Scrape wikipedia-science: 10859 new, 3607 updated, 14832 total (kb-cron)

data/en.wikipedia.org/wiki/IEEE_Robert_N._Noyce_Medal-0.md

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+---
+title: "IEEE Robert N. Noyce Medal"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/IEEE_Robert_N._Noyce_Medal"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:53:10.928167+00:00"
+instance: "kb-cron"
+---
+
+The IEEE Robert N. Noyce Medal is a science award presented by the IEEE for outstanding contributions to the microelectronics industry. It is given to individuals who have demonstrated contributions in multiple areas including technology development, business development, industry leadership, development of technology policy, and standards development. The medal is named in honour of Robert N. Noyce, the co-founder of Intel Corporation. He was also renowned for his 1959 invention of the integrated circuit. The medal is funded by Intel Corporation and was first awarded in 2000.
+
+
+== Recipients ==
+Source:
+
+
+== References ==
+
+
+== External links ==
+IEEE Robert N. Noyce Medal, Institute of Electrical and Electronics Engineers
+Recipients of the Robert N. Noyce Medal,  Institute of Electrical and Electronics Engineers

data/en.wikipedia.org/wiki/Orders_of_magnitude_(torque)-0.md

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+---
+title: "Orders of magnitude (torque)"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Orders_of_magnitude_(torque)"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:52:07.196535+00:00"
+instance: "kb-cron"
+---
+
+The following are examples of orders of magnitude for torque.
+
+
+== Examples ==
+
+
+== References ==

data/en.wikipedia.org/wiki/Oswald_efficiency_number-0.md

@@ -0,0 +1,329 @@
+---
+title: "Oswald efficiency number"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Oswald_efficiency_number"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:52:08.344773+00:00"
+instance: "kb-cron"
+---
+
+The Oswald efficiency, similar to the span efficiency, is a correction factor that represents the change in drag with lift of a three-dimensional wing or airplane, as compared with an ideal wing having the same aspect ratio and an elliptical lift distribution.
+
+
+== Definition ==
+The Oswald efficiency is defined for the cases where the overall coefficient of drag of the wing or airplane has a constant+quadratic dependence on the aircraft lift coefficient
+
+  
+    
+      
+        
+          C
+          
+            D
+          
+        
+        =
+        
+          C
+          
+            
+              D
+              
+                0
+              
+            
+          
+        
+        +
+        
+          
+            
+              (
+              
+                C
+                
+                  L
+                
+              
+              
+                )
+                
+                  2
+                
+              
+            
+            
+              π
+              
+                e
+                
+                  0
+                
+              
+              A
+              R
+            
+          
+        
+      
+    
+    {\displaystyle C_{D}=C_{D_{0}}+{\frac {(C_{L})^{2}}{\pi e_{0}AR}}}
+  
+
+where
+
+For conventional fixed-wing aircraft with moderate aspect ratio and sweep, Oswald efficiency number with wing flaps retracted is typically between 0.7 and 0.85.  At supersonic speeds, Oswald efficiency number decreases substantially.  For example, at Mach 1.2 Oswald efficiency number is likely to be between 0.3 and 0.5.
+
+
+== Comparison with span efficiency factor ==
+It is frequently assumed that Oswald efficiency number is the same as the span efficiency factor which appears in lifting-line theory, and in fact the same symbol e is typically used for both. But this assumes that the profile drag coefficient is independent of 
+  
+    
+      
+        
+          C
+          
+            L
+          
+        
+      
+    
+    {\displaystyle C_{L}}
+  
+, which is certainly not true in general. Assuming that the profile drag itself has a constant+quadratic dependence on 
+  
+    
+      
+        
+          C
+          
+            L
+          
+        
+      
+    
+    {\displaystyle C_{L}}
+  
+,
+an alternative drag coefficient breakdown can be given by
+
+  
+    
+      
+        
+          C
+          
+            D
+          
+        
+        =
+        
+          c
+          
+            
+              d
+              
+                0
+              
+            
+          
+        
+        +
+        
+          c
+          
+            
+              d
+              
+                2
+              
+            
+          
+        
+        (
+        
+          C
+          
+            L
+          
+        
+        
+          )
+          
+            2
+          
+        
+        +
+        
+          
+            
+              (
+              
+                C
+                
+                  L
+                
+              
+              
+                )
+                
+                  2
+                
+              
+            
+            
+              π
+              e
+              A
+              R
+            
+          
+        
+      
+    
+    {\displaystyle C_{D}=c_{d_{0}}+c_{d_{2}}(C_{L})^{2}+{\frac {(C_{L})^{2}}{\pi eAR}}}
+  
+
+where
+
+Equating the two 
+  
+    
+      
+        
+          C
+          
+            D
+          
+        
+      
+    
+    {\displaystyle C_{D}}
+  
+ expressions gives the relation between the Oswald efficiency number e0 and the lifting-line span efficiency e.
+
+  
+    
+      
+        
+          C
+          
+            
+              D
+              
+                0
+              
+            
+          
+        
+        =
+        
+          c
+          
+            
+              d
+              
+                0
+              
+            
+          
+        
+      
+    
+    {\displaystyle C_{D_{0}}=c_{d_{0}}}
+  
+
+  
+    
+      
+        
+          
+            1
+            
+              e
+              
+                0
+              
+            
+          
+        
+        =
+        
+          
+            1
+            e
+          
+        
+        +
+        π
+        A
+        R
+        
+          c
+          
+            
+              d
+              
+                2
+              
+            
+          
+        
+      
+    
+    {\displaystyle {\frac {1}{e_{0}}}={\frac {1}{e}}+\pi ARc_{d_{2}}}
+  
+
+For the typical situation 
+  
+    
+      
+        
+          c
+          
+            
+              d
+              
+                2
+              
+            
+          
+        
+        >
+        0
+      
+    
+    {\displaystyle c_{d_{2}}>0}
+  
+, we have 
+  
+    
+      
+        
+          e
+          
+            0
+          
+        
+        <
+        e
+      
+    
+    {\displaystyle e_{0}<e}
+  
+.
+
+
+== See also ==
+Lift-induced drag
+Lifting-line theory
+
+
+== Notes ==
+
+
+== References ==
+Raymer, Daniel P. (2006).  Aircraft Design: A Conceptual Approach, Fourth edition. AIAA Education Series.  ISBN 1-56347-829-3
+Anderson, John D. (2008). Introduction to Flight, Sixth edition. McGraw Hill. ISBN 0-07-126318-7
+PhD. William Bailey Oswald, https://calteches.library.caltech.edu/3961/1/Obituaries.pdf

data/en.wikipedia.org/wiki/Output_signal_switching_device-0.md

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+---
+title: "Output signal switching device"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Output_signal_switching_device"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:52:09.556328+00:00"
+instance: "kb-cron"
+---
+
+An output signal switching device (OSSD) is an electronic device used as part of the safety system of a machine. When monitored safety conditions (e.g. optically scanned opening) transition from safe to unsafe condition state (are tripped) - OSSD immediately signals the machine to shut down via hardwired safety output channel signals. As a further layer of redundancy protection, it provides a current-sourcing PNP safety output signals with built-in test pulses (or other method of detecting faults) on two parallel channels to detect any combination of shorting or miswiring. This is accomplished  by converting the standard direct current supply, usually 24 volts, into two pulsed and out-of-phase safety output signals. The benefit of this is to avoid the possibility of a stray signal keeping the machine operating while actually in an unsafe condition.
+
+
+== Typical Application ==
+The typical application is a machine guard or light curtain that is protecting an automated manufacturing cell containing a robot, press or some other type of dangerous machinery.  If the machine guard is open, it is possible that someone is attempting to access the machinery.  In this case, the sensor is "tripped", and power is removed from the robot.  The tripped state is the 0 VDC state.
+If the guard is closed, then the machine is allowed to operate.  This is the "active" state or "non-tripped" condition, normally 24 VDC.
+OSSD resolves a specific problem.  If the wires connecting to the sensor become shorted, then an open guard could read closed.  This is hazardous if someone is present.  OSSD prevents a short circuit from detecting as a guard closed.  
+In many applications OSSD sensors are used in a dual-channel configuration.  The likelihood of an accidental short circuit can be very low.  However, electronics can fail shorted.  In some applications, the possibility of a deliberate short circuit exists.  Correctly utilized, OSSD prevents the guard from reading as closed due to any electrical short circuit in the sensor wiring or electronic circuit.
+
+
+== Technical description ==
+The device usually acts as the interface of a sensor (such as a light curtain), designed to signal a safety-related event, typically when the light curtain beam's being "broken". OSSD signals are the outputs from the protective device (light curtain or scanner) to a safety relay. OSSD outputs are typically semiconductor or transistor outputs, as opposed to relay or contact type outputs. There are usually two independent channels, so-called OSSD1 and OSSD2.
+The non-tripped state is typically 24 VDC, and the tripped state (when the safety barrier has been violated) 0 VDC. If a wire were to break between the light curtain and the safety relay, the safety relay would trip to the safe state.
+The OSSD outputs are self-checked. In the non-tripped state, the outputs periodically pulse low. The protective device checks the output, to make sure it does indeed go low when commanded. If not, the output may have failed or has shorted to 24V somewhere else. Between OSSD1 and OSSD2 the pulse intervals are staggered to check for crisscrossed wiring between the two.
+The technology relies on two independent channels carrying the same information output by the device:
+The OSSD technology and a classification of timing and other properties are described in the "Position Paper CB24I" issued by ZVEI - German Electrical and Electronic Manufacturer's Association. 
+OSSD signals are typically of Interface type C as described in CB24I.
+
+Idle signal is 24 V, periodically shortly pulsed to 0 V (pulses are not synchronous) in order for the receiver to ensure no shortcut to either 0 V or 24 V.
+Active signal is issued when both lines present 0 V; a single line presenting 0 V for a duration longer than the test pulses is sufficient to signal an event.
+Some related terms:
+
+Electrosensitive protective equipment (ESPE) - a device such as a light curtain, safety scanner, or gate position sensor. The ESPE has OSSD outputs.
+External Device Monitor (EDM). The device issuing the OSSD signals may have an EDM input. The EDM is used to verify that the controlled device (safety relay) did indeed open when the OSSD signals were dropped. The safety relay has normally closed contacts, which close when the relay is de-energized, thereby turning on the EDM input.
+
+
+== See also ==
+Automation
+Safety engineering
+
+
+== References ==
+
+European patent EP 2 362 408 B1 accorded to Rockwell Automation Germany GmbH & Co. KG, with chronograms and examples.
+Article from the review Instrumentation and Control (South Africa) explaining use cases.

data/en.wikipedia.org/wiki/Overflow_downdraw_method-0.md

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+---
+title: "Overflow downdraw method"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Overflow_downdraw_method"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:52:10.739037+00:00"
+instance: "kb-cron"
+---
+
+The overflow downdraw method or fusion method is a technique for producing flat glass. A sheet of glass is formed when molten glass overflows from a supply trough, flows down both sides, and rejoins (fuses) at the tapered bottom, where it is drawn away in sheet form.
+The key advantage of this technique as compared to the float glass process is that the pristine surfaces are not touched by molten tin. The technique is used for the production of very thin flat panel display glass by the companies Asahi Glass Co., Corning,  Nippon Electric Glass,
+Samsung Corning Precision Materials, 
+and various other companies operating in the field of display glass and other types of thin glass.
+The fusion method was originally conceived by Corning in the 1960s as a method for manufacturing automotive windshields. Shelved for years, the technology was reintroduced to supply the flat screen display market.
+
+
+== References ==
+
+
+== External links ==
+US Patent 851627, June 15, 2004
+US Patent 6990834, January 31, 2006
+Huey-Jiuan Lin, Wei-Kuo Chang: Design of a sheet forming apparatus for overflow fusion process by numerical simulation; Journal of Non-Crystalline Solids, Volume 353, Issues 30-31, 1 October 2007, Pages 2817-2825 Full text article
+description of the fusion overflow process at the Corning website

data/en.wikipedia.org/wiki/Overhaul_ball-0.md

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+---
+title: "Overhaul ball"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Overhaul_ball"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:52:11.899290+00:00"
+instance: "kb-cron"
+---
+
+An overhaul ball, also known as an overhaul hook ball or headache ball, is a heavy weight that is attached to the end of a crane's cable, above the lifting hook. It is used to keep the cable under sufficient tension even when no load is attached. Although commonly spherical as the name suggests, overhaul balls may also be ellipsoidal or cylindrical.
+Overhaul balls should be distinguished from wrecking balls, which although superficially similar looking, are different and serve a different purpose.
+
+
+== References ==

data/en.wikipedia.org/wiki/Overhead_(engineering)-0.md

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+---
+title: "Overhead (engineering)"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Overhead_(engineering)"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:52:13.100221+00:00"
+instance: "kb-cron"
+---
+
+In engineering, some methods or components make special demands on the system.  The extra design features necessary to meet these demands are called overhead. For instance, in electrical engineering, a particular integrated circuit might draw large current, requiring a robust power delivery circuit and a heat-dissipation mechanism.
+
+
+== See also ==
+Overhead (business)
+Overhead (computing)
+
+
+== References ==

data/en.wikipedia.org/wiki/PD_5500-0.md

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+---
+title: "PD 5500"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/PD_5500"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:52:17.791263+00:00"
+instance: "kb-cron"
+---
+
+PD 5500 is a specification for unfired pressure vessels. It specifies requirements for the design, manufacture, inspection and testing of unfired pressure vessels made from carbon, ferritic alloy, and austenitic steels. It also includes material supplements containing requirements for vessels made from aluminium, copper, nickel, titanium and duplex.
+PD 5500 is the UK’s national pressure vessels code, although the code is used outside the UK. A new edition of PD5500 is published every three years. An amendment is usually published every year in September.
+BS5500 was declassified as a full British Standard and reclassified as a 'Publicly Available Specification', which lead to it being renamed to PD5500. PD5500 was withdrawn from the list of British Standards because it was not harmonized with the European Pressure Equipment Directive (2014/68/EU formerly 97/23/EC) . EN 13445 was introduced as the harmonized standard. Harmonized standards carry presumed conformity with the requirements of the Pressure Equipment Directive, whereas other pressure vessel design codes such as PD5500 or ASME must demonstrate conformity against each of the Essential Safety Requirements of the Pressure Equipment Directive before conformity can be declared. PD5500 is currently published as a "Published Document" (PD) by the British Standards Institution.
+
+
+== Brexit ==
+In the UK the Pressure Equipment Safety Regulations 2016 enacted the PED into UK law. Since the UK exited the European Union, the PED no longer applies and the Pressure Equipment Safety Regulations 2016 have been amended by the enactment of the UK Product Safety and Metrology Regulations, which update a number of pieces of legislation which required amendments to operate outside of the EU.
+Under this new legislation Harmonised Standards are now referred to as Designated Standards, but the practice of demonstrating compliance remains largely the same. EN 13445 is recognised as a Designated Standard, while other codes such as PD5500 must still demonstrate conformity against each Essential Safety Requirement.
+
+
+== See also ==
+Pressure Equipment Directive
+Pressure Equipment Safety Regulations
+The Product Safety and Metrology etc. (Amendment etc.) (EU Exit) Regulations 2019
+PD5500 - British Standard Institute
+
+
+== References ==

data/en.wikipedia.org/wiki/Pacific_Coast_Electric_Transmission_Association-0.md

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+---
+title: "Pacific Coast Electric Transmission Association"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Pacific_Coast_Electric_Transmission_Association"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:52:14.287401+00:00"
+instance: "kb-cron"
+---
+
+The Pacific Coast Electric Transmission Association was an American engineering institute founded in 1884 in response to the East coast establishment of the American Institute of Electrical Engineers.  It published its proceedings in the journalist George P. Low's journal The Electrical Journal, later titled The Journal of Electricity and then The Journal of Electricity, Power, and Gas, and began annual meetings in 1898.  The annual meeting acted as both an electrical industry conference and an academic conference in electrical engineering.  It disbanded with the continuation of the AIEE to the West coast in or shortly after 1905.
+
+
+== References ==

data/en.wikipedia.org/wiki/Packaged_terminal_air_conditioner-0.md

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+---
+title: "Packaged terminal air conditioner"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Packaged_terminal_air_conditioner"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:52:15.421442+00:00"
+instance: "kb-cron"
+---
+
+A packaged terminal air conditioner (PTAC) is a type of self-contained heating and air conditioning system intended to be mounted through a wall. The first practical semi-portable air conditioning unit was invented by engineers at Chrysler Motors. It entered the market in 1935, and was designed to fit under a window like many modern PTACs.
+PTACs are commonly found in commercial settings (hotels, motels, hospitals), or multifamily facilities (senior housing, condominiums, apartment buildings). PTACs are mostly used to cool individual living spaces, there are units which offer resistance heating and/or heat pumps. (The latter are more properly described as packaged terminal heat pumps or PTHP). PTACs with support for external heating through a hydronic heating coil or natural gas heating also exist. Typical PTAC heating and cooling capacity values range from 7,000–19,000 BTU/h (2 to 5.5 kilowatts) nominal.
+PTACs are commonly installed in window walls and masonry walls, with multiple standard dimensions available including 42×16 inches (1067x406 mm), 36x15 inches, and 40x15 inches. Their installation typically requires the following:
+
+Louvers
+Metal sleeve
+Heating coil
+The PTAC itself
+Room enclosure
+
+Some models have the ability, if the control board is so equipped, to add a remote thermostat. This functionality relies on a RF link.
+
+
+== References ==

data/en.wikipedia.org/wiki/Passivhaus-Institut-0.md

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+---
+title: "Passivhaus-Institut"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Passivhaus-Institut"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:52:16.577926+00:00"
+instance: "kb-cron"
+---
+
+The Passivhaus-Institut (PHI) is responsible for promoting and maintaining the Passivhaus building program.  The "Passivhaus Institute" was founded in 1996, and is based and active in Darmstadt, Germany.
+The English spelling was used for the Passive House Institute US (PHIUS) when it formed in 2007   originally under the umbrella of the Passivhaus Institute. The two separated in 2012.
+Though PHI and PHIUS sustainable design standards are different, they both share common goals for drastic energy conservation and carbon reduction through sustainable architecture design techniques and specifications to create low-energy houses and other structures with low energy building practices for the public benefit worldwide.
+
+
+== See also ==
+
+List of low-energy building techniques
+History of passive solar building design
+Energy-efficient landscaping
+
+
+== References ==

data/en.wikipedia.org/wiki/Per_cent_mille-0.md

@@ -0,0 +1,94 @@
+---
+title: "Per cent mille"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Per_cent_mille"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:52:18.992940+00:00"
+instance: "kb-cron"
+---
+
+A per cent mille, or pcm, is a hundred-thousandth, or a thousandth of a percent. It can be thought of as a "milli-percent". It is commonly used in epidemiology, and in nuclear reactor engineering as a unit of reactivity.
+
+
+== Epidemiology ==
+Statistics of crime rates, mortality and disease prevalence in a population are often given in "per 100 000".
+
+
+== Nuclear reactivity ==
+In nuclear reactor engineering, a per cent mille is equal to one-thousandth of a percent of the reactivity, denoted by Greek lowercase letter rho. Reactivity is a dimensionless unit representing a departure from criticality, calculated by:
+
+  
+    
+      
+        ρ
+        =
+        (
+        
+          k
+          
+            eff
+          
+        
+        −
+        1
+        )
+        
+          /
+        
+        
+          k
+          
+            eff
+          
+        
+      
+    
+    {\displaystyle \rho =(k_{\text{eff}}-1)/k_{\text{eff}}}
+  
+
+where keff denotes the effective multiplication factor for the reaction. Therefore, one pcm is equal to:
+
+  
+    
+      
+        1
+         
+        
+          pcm
+        
+        =
+        ρ
+        ⋅
+        
+          10
+          
+            5
+          
+        
+      
+    
+    {\displaystyle 1~{\text{pcm}}=\rho \cdot 10^{5}}
+  
+
+This unit is commonly used in the operation of light-water reactor sites because reactivity values tend to be small, so measuring in pcm allows reactivity to be expressed using whole numbers.
+
+
+== Related units ==
+Percentage point difference of 1 part in 100
+Percentage (%) 1 part in 100
+Per mille (‰) 1 part in 1,000
+Basis point (bp) difference of 1 part in 10,000
+Permyriad (‱) 1 part in 10,000
+Parts-per notation including parts-per million, parts-per billion etc
+
+
+== See also ==
+InHour (another unit of reactivity)
+Dollar (reactivity)
+Parts-per notation
+Per-unit system
+Percent point function
+
+
+== Notes ==

data/en.wikipedia.org/wiki/Permissible_stress_design-0.md

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+---
+title: "Permissible stress design"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Permissible_stress_design"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:52:20.165956+00:00"
+instance: "kb-cron"
+---
+
+Permissible stress design is a design philosophy used by mechanical engineers and civil engineers.
+The civil designer ensures that the stresses developed in a structure due to service loads do not exceed the elastic limit. This limit is usually determined by ensuring that stresses remain within the limits through the use of factors of safety.
+In structural engineering, the permissible stress design approach has generally been replaced internationally by limit state design (also known as ultimate stress design, or in USA, Load and Resistance Factor Design, LRFD) as far as structural engineering is considered, except for some isolated cases.
+In USA structural engineering construction, allowable stress design (ASD) has not yet been completely superseded by limit state design except in the case of Suspension bridges, which changed from allowable stress design to limit state design in the 1960s. Wood, steel, and other materials are still frequently designed using allowable stress design, although LRFD is probably more commonly taught in the USA university system.
+In mechanical engineering design such as design of pressure equipment, the method uses the actual loads predicted to be experienced in practice to calculate stress and deflection. Such loads may include pressure thrusts and the weight of materials. The predicted stresses and deflections are compared with allowable values that have a "factor" against various failure mechanisms such as leakage, yield, ultimate load prior to plastic failure, buckling, brittle fracture, fatigue, and vibration/harmonic effects. However, the predicted stresses almost always assumes the material is linear elastic. The "factor" is sometimes called a factor of safety, although this is technically incorrect because the factor includes allowance for matters such as local stresses and manufacturing imperfections that are not specifically calculated; exceeding the allowable values is not considered to be good practice (i.e. is not "safe").
+The permissible stress method is also known in some national standards as the working stress method because the predicted stresses are the unfactored stresses expected during operation of the equipment (e.g. AS1210, AS3990).
+This mechanical engineering approach differs from an ultimate design approach which factors up the predicted loads for comparison with an ultimate failure limit. One method factors up the predicted load, the other method factors down the failure stress.
+
+
+== See also ==
+Allowable Strength Design
+Building code
+
+
+== References ==

data/en.wikipedia.org/wiki/Perry–Robertson_formula-0.md

@@ -0,0 +1,257 @@
+---
+title: "Perry–Robertson formula"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Perry–Robertson_formula"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:52:21.371187+00:00"
+instance: "kb-cron"
+---
+
+The Perry–Robertson formula is a mathematical formula which is able to produce a good approximation of buckling loads in long slender columns or struts, and is the basis for the buckling formulation adopted in EN 1993.  
+The formula in question can be expressed in the following form:
+
+  
+    
+      
+        
+          σ
+          
+            m
+          
+        
+        =
+        
+          
+            1
+            2
+          
+        
+        
+          (
+          
+            
+              f
+              
+                y
+              
+            
+            +
+            
+              σ
+              
+                e
+              
+            
+            
+              (
+              
+                1
+                +
+                θ
+              
+              )
+            
+            −
+            
+              
+                
+                  
+                    (
+                    
+                      
+                        f
+                        
+                          y
+                        
+                      
+                      +
+                      
+                        σ
+                        
+                          e
+                        
+                      
+                      
+                        (
+                        
+                          1
+                          +
+                          θ
+                        
+                        )
+                      
+                    
+                    )
+                  
+                  
+                    2
+                  
+                
+                −
+                4
+                
+                  f
+                  
+                    y
+                  
+                
+                
+                  σ
+                  
+                    e
+                  
+                
+              
+            
+          
+          )
+        
+      
+    
+    {\displaystyle \sigma _{m}={\frac {1}{2}}\left(f_{y}+\sigma _{e}\left(1+\theta \right)-{\sqrt {\left(f_{y}+\sigma _{e}\left(1+\theta \right)\right)^{2}-4f_{y}\sigma _{e}}}\right)}
+  
+
+with 
+
+  
+    
+      
+        θ
+        =
+        
+          
+            
+              
+                w
+                
+                  o
+                  ,
+                  1
+                
+              
+              c
+            
+            
+              i
+              
+                2
+              
+            
+          
+        
+      
+    
+    {\displaystyle \theta ={\frac {w_{o,1}c}{i^{2}}}}
+  
+
+where:
+
+  
+    
+      
+        
+          σ
+          
+            m
+          
+        
+      
+    
+    {\displaystyle \sigma _{m}}
+  
+ is the average longitudinal stress in the beam's cross section
+
+  
+    
+      
+        
+          f
+          
+            y
+          
+        
+      
+    
+    {\displaystyle f_{y}}
+  
+ is the material's elastic limit
+
+  
+    
+      
+        
+          σ
+          
+            e
+          
+        
+      
+    
+    {\displaystyle \sigma _{e}}
+  
+ is the average tension measured in the cross section which correspond to the beam's Euler load
+
+  
+    
+      
+        
+          w
+          
+            o
+            ,
+            1
+          
+        
+      
+    
+    {\displaystyle w_{o,1}}
+  
+ the amplitude of the initial geometrical imperfection
+
+  
+    
+      
+        c
+      
+    
+    {\displaystyle c}
+  
+ distance from the cross section's centroid to the section's most stressed fiber
+
+  
+    
+      
+        i
+      
+    
+    {\displaystyle i}
+  
+ the section's radius of gyration
+Robertson then proposed that 
+  
+    
+      
+        θ
+        =
+        0.003
+        λ
+      
+    
+    {\displaystyle \theta =0.003\lambda }
+  
+, where 
+  
+    
+      
+        λ
+      
+    
+    {\displaystyle \lambda }
+  
+ represents the beam's slenderness.
+
+
+== References ==
+"Perry Robertson formula (BS 449-2 )". Archived from the original on 2011-01-08. Retrieved 2010-11-22.
+Ryall, M. J.; Hewson, Nigel; Parke, G. A. R.; Harding, J. E. (2000). The manual of bridge engineering. ISBN 9780727727749. Retrieved 2010-11-22.

data/en.wikipedia.org/wiki/Phu_Phong_Glass_Joint_Stock_Company-0.md

@@ -0,0 +1,25 @@
+---
+title: "Phu Phong Glass Joint Stock Company"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Phu_Phong_Glass_Joint_Stock_Company"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:52:22.598227+00:00"
+instance: "kb-cron"
+---
+
+Phu Phong Glass Joint Stock Company (CTCP Sản xuất Thương mại Dịch vụ Phú Phong) is a company based in the outskirts of Ho Chi Minh City that makes architectural glass and float glass for use in furniture and construction materials.  Phu Phong's main offices are in Ho Chi Minh City.  Its stock is listed at the Hanoi Securities Trading Center, symbol is PPG.
+
+
+== See also ==
+List of companies of Vietnam
+
+
+== References ==
+
+
+== External links ==
+Phu Phong Glass official page
+Phu Phong Glass' page at Importgenius
+Phu Phong Glass' page at Alacrastore
+Phu Phong Glass' page at Hanoi Securities Trading Center

data/en.wikipedia.org/wiki/Pile_cap-0.md

@@ -0,0 +1,26 @@
+---
+title: "Pile cap"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Pile_cap"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:52:23.731113+00:00"
+instance: "kb-cron"
+---
+
+A pile cap is a thick concrete mat that rests on concrete or timber piles that have been driven into soft or unstable ground to provide a suitable stable foundation. It usually forms part of the deep foundation of a building, typically a multi-story building, structure or support base for heavy equipment, or of a bridge. The cast concrete pile cap distributes the load of the building into the piles. A similar structure to a pile cap is a "raft", which is a concrete foundation floor resting directly onto soft soil which may be liable to subsidence.
+
+
+== Design ==
+
+
+== Construction ==
+The mat is made of concrete which is an aggregate of small rocks and cement. This mixture has to be supported by a framework to avoid sagging and fracture while setting. This process is known as shuttering and reinforcing. The materials used are long steel bars with longitudinal protrusions between the piles held in shape by thinner tie wires. Once this steel mat is laid, timber is attached around the perimeter to contain the wet concrete mixture. Once poured, (usually as a series of small loads), the concrete is stirred to remove any air pockets that might weaken the structure when set. The concrete undergoes a chemical change as it hardens and this produces a lot of heat. Sometimes, if the mass of concrete is very large, pipes carrying refrigerant coolant are used in the mass to assist the setting process to prevent the concrete from cracking.
+
+
+== See also ==
+Foundation (engineering)
+Underpinning
+
+
+== References ==

data/en.wikipedia.org/wiki/Ping_test_(engineering)-0.md

@@ -0,0 +1,19 @@
+---
+title: "Ping test (engineering)"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Ping_test_(engineering)"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:52:24.879312+00:00"
+instance: "kb-cron"
+---
+
+A ping test is a physical test to determine the natural frequency of an object or assembly. The test consists of instrumenting the object or assembly with measuring devices and then tapping it with another metallic object (usually a hammer.) The undamped system will then vibrate at its natural frequency.  The ping test is used on assemblies and objects where vibration can be an issue.
+
+
+== See also ==
+Ping
+Ping test
+
+
+== References ==

data/en.wikipedia.org/wiki/Pinion-0.md

@@ -0,0 +1,35 @@
+---
+title: "Pinion"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Pinion"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:52:26.082961+00:00"
+instance: "kb-cron"
+---
+
+A pinion is a round gear—usually the smaller of two meshed gears—used in several applications, including drivetrain and rack and pinion systems.
+
+
+== Applications ==
+
+
+=== Drivetrain ===
+Drivetrains usually feature a gear known as the pinion, which may vary in different systems, including
+
+the typically smaller gear in a gear drive train (although in the first commercially successful steam locomotive—the Salamanca—the pinion was rather large). In many cases, such as remote controlled toys, the pinion is also the drive gear for a reduction in speed, since electric motors operate at higher speed and lower torque than desirable at the wheels. However the reverse is true in watches, where gear trains commence with a high-torque, low-speed spring and terminate in the fast-and-weak escapement.
+the smaller gear that drives in a 90-degree angle towards a crown gear in a differential drive.
+the small front sprocket on a chain driven motorcycle.
+the clutch bell gear when paired with a centrifugal clutch, in radio-controlled cars with an engine (e.g., nitro).
+
+
+=== Rack and pinion ===
+
+In rack and pinion systems, the pinion is the round gear that engages and moves along the linear rack.
+
+
+== See also ==
+List of gear nomenclature
+
+
+== References ==

data/en.wikipedia.org/wiki/Plumbing_drawing-0.md

@@ -0,0 +1,34 @@
+---
+title: "Plumbing drawing"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Plumbing_drawing"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:52:27.236408+00:00"
+instance: "kb-cron"
+---
+
+A plumbing drawing, a type of technical drawing, shows the system of piping for fresh water going into the building and waste going out, both solid and liquid.
+It also includes fuel gas drawings. Mainly plumbing drawing consist of water supply system drawings, drainage system drawings, irrigation system drawings, storm water system drawings. 
+In water supply system drawing there will be hot water piping and cold water piping and hot water return piping also. 
+In drainage system drawings there will be waste piping, Soil piping and vent piping. 
+The set of drawing of each system like water supply, drainage etc is consist of Plans, Riser diagram, Installation details, Legends, Notes. 
+Every pipes should me marked with pipe sizes. 
+If the drawing is detailed, fixture units also should be marked along with the pipe. 
+In the realm of shop drawings, additional clarity is achieved by incorporating sections that reveal the intersection points of various pipes. These sections serve as visual guides, ensuring that the intricate network of pipes is comprehensively depicted. 
+In shop drawings pipe sizes should be marked with the text and size should be shown with double line.
+Each pipes with different purposes will be displayed with different colors for ease of understanding. Drainage pipes should be shown with slope. 
+For water supply, pump capacity and number of pumps will be attached as drawing file. 
+For drainage, manhole schedule which consist of each manhole name, Invert level, Cover level, Depth are also attached as drawing file.
+
+
+== See also ==
+Architectural drawing
+Electrical drawing
+Engineering drawing
+Mechanical systems drawing
+Structural drawing
+Working drawing
+
+
+== References ==

data/en.wikipedia.org/wiki/Polished_plate_glass-0.md

@@ -0,0 +1,18 @@
+---
+title: "Polished plate glass"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Polished_plate_glass"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:52:28.378741+00:00"
+instance: "kb-cron"
+---
+
+Polished plate is a type of hand-made glass. It is produced by casting glass onto a table and subsequently grinding and polishing the glass. This was originally done by hand, and then later by machine. It was an expensive process requiring a large capital investment.
+Other methods of producing hand-blown window glass included: broad sheet, blown plate, crown glass and cylinder blown sheet. These methods of manufacture lasted at least until the end of the 19th century.  The early 20th century marks the move away from hand-blown to machine manufactured glass such as rolled plate, machine drawn cylinder sheet, flat drawn sheet, polished plate glass, and float glass.
+In 1688, the Frenchman Louis Lucas de Nehou, in conjunction with Abraham Thevart, succeeded in perfecting the process of casting plate-glass. Mirror plates prior to the invention had been made from blown "sheet" glass, and were consequently very limited in size. De Nehou's process of rolling molten glass poured on an iron table rendered the manufacture of very large plates possible.
+In 1773 English polished plate (by the French process) was produced at Ravenhead.
+By 1800 a steam engine was used to carry out the grinding and polishing of the cast glass.
+
+
+== References ==

data/en.wikipedia.org/wiki/Position_tolerance-0.md

@@ -0,0 +1,20 @@
+---
+title: "Position tolerance"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Position_tolerance"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:52:29.538832+00:00"
+instance: "kb-cron"
+---
+
+Position tolerance (symbol: ⌖) is a geometric dimensioning and tolerancing (GD&T) location control used on engineering drawings to specify desired location, as well as allowed deviation to the position of a feature on a part. 
+Position tolerance must only be applied to features of size, which requires that the feature have at least two opposable points.
+
+
+== See also ==
+Circle
+Miscellaneous Technical, a Unicode block containing various common technical and academic symbols
+
+
+== References ==

data/en.wikipedia.org/wiki/Power_density-0.md

@@ -0,0 +1,69 @@
+---
+title: "Power density"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Power_density"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:52:30.742208+00:00"
+instance: "kb-cron"
+---
+
+Power density is the amount of power (time rate of energy transfer) per unit volume. It is typically measured in watts per cubic meter (W/m³) and represents how much power is distributed within a given space. In various fields such as physics, engineering, and electronics, power density is used to evaluate the efficiency and performance of devices, systems, or materials by considering how much power they can handle or generate relative to their size or volume.
+In energy transformers including batteries, fuel cells, motors, power supply units, etc., power density refers to a volume, where it is often called volume power density, expressed as W/m3.
+In reciprocating internal combustion engines, power density (power per swept volume or brake horsepower per cubic centimetre) is an important metric, solely based on the internal capacity of the engine, not its external size.
+
+
+== Definition ==
+Power density is commonly defined as the converter’s rated (nominal) output power divided by the physical volume it occupies:
+
+  
+    
+      
+        
+          
+            
+              
+                V
+                
+                  0
+                
+              
+              
+                I
+                
+                  0
+                
+              
+            
+            
+              x
+              y
+              z
+            
+          
+        
+      
+    
+    {\displaystyle {\frac {V_{0}I_{0}}{xyz}}}
+  
+
+For comparative purposes, the output power typically denotes the continuous power that can be delivered under specified worst-case environmental conditions. Typical determinants include ambient temperature, maximum permissible case temperature, unit orientation and airflow, operating altitude, and reliability or lifetime targets that may require derating.
+The converter’s volume may be defined in several ways depending on the application and construction. Reported values may include or exclude components such as electromagnetic interference (EMI) filters, thermal management hardware (e.g., fans or heatsinks), protective housings or enclosures, connectors, and input or output energy-storage capacitors. These components are often required in end products but may be omitted when measuring modular power supplies.
+
+
+== History ==
+The relevance of power density has gradually increased from the advent of switched-mode power conversion, with efficiency being the primary drive. Switching converters enables performance beyond the deterministic limits of linear power supplies, whose efficiencies were largely constrained by input-output voltage ratios and a small set of available topologies. 
+Beginning in the early 1990s, efficiency improvements accelerated, driven by the expansion of personal computing and consumer electronics, growth in telecommunications, and rapid progress in semiconductor technology. As conversion efficiency increased, attainable power density rose in parallel, reflecting the close coupling between these metrics.
+Successive energy crises and the resulting regulatory frameworks elevated efficiency from a desirable attribute to a practical requirement, with emphasis on energy conservation and total cost of ownership across the life cycle of power systems. This eventually caused high power density to become regarded as a leading benchmark of power-system engineering, being the convergence of efficiency, compactness, and performance in modern power-delivery design.
+
+
+== Examples ==
+
+
+== See also ==
+Energy density, energy per unit volume
+Specific energy, energy per unit mass
+Specific absorption rate (SAR)
+
+
+== References ==

data/en.wikipedia.org/wiki/Powerpack_(drivetrain)-0.md

@@ -0,0 +1,31 @@
+---
+title: "Powerpack (drivetrain)"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Powerpack_(drivetrain)"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:52:31.925418+00:00"
+instance: "kb-cron"
+---
+
+A powerpack or power pack is a part of a modular powertrain that contains some type of engine (most frequently an internal combustion engine, ⁣⁣ but other types, including electric motors, are possible) and may also contain a transmission and various supporting components.
+
+
+== Applications ==
+Power packs are used with certain types of industrial equipment designs, including vehicle designs such as self-propelled modular transporter, hydraulic modular trailer, forklifts and cherry picker lifts, but also stationary equipment such as paint sprayers. Virtually all modern military tanks use them, an early example being the M26 Pershing and Chieftain, and many other military vehicles as well.
+
+
+== Advantages ==
+
+The modularity is what makes a powerpack powertrain different from other types; using the term powerpack implies that the whole unit can be easily removed or separated from the rest of the machine, allowing it to be rapidly replaced by another powerpack while the original is repaired or disposed of, and minimizing the amount of time that the entire machine is out of use. Even in cases where the powerpack is not being replaced, being able to remove it can make repairs easier and faster.
+
+
+== See also ==
+Prime mover
+Power-egg
+Power module
+Hydraulic modular trailer
+Self-propelled modular transporter
+
+
+== References ==

data/en.wikipedia.org/wiki/Pressure_Vessel_for_Human_Occupancy-0.md

@@ -0,0 +1,41 @@
+---
+title: "Pressure Vessel for Human Occupancy"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Pressure_Vessel_for_Human_Occupancy"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:52:33.141130+00:00"
+instance: "kb-cron"
+---
+
+The American Society of Mechanical Engineers defines a Pressure Vessel for Human Occupancy (PVHO) as a container that is intended to be occupied by one or more persons at a pressure which differs from ambient by at least 2 pounds per square inch (0.14 bar). Since 1977, the ASME's PVHO committee has published standards governing the construction of a number of PVHO applications. The current design standard is PVHO-1-2023. The current code for maintenance and operation guidances is ASME PVHO-2-2019. Similar standards are published by a range of national and international standards organisations.
+
+
+== List of PVHO types ==
+Types of pressure vessels for human occupancy include:
+
+diving chambers
+decompression chambers
+closed diving bells, also known as dry bells or personnel transfer capsules
+high altitude chambers
+hyperbaric chambers
+hyperbaric stretchers
+medical hyperbaric oxygenation facilities
+recompression chambers
+submarines
+crewed submersibles
+atmospheric diving suits
+pressurized tunnel boring machines
+A typical pressure vessel is not defined until there is at least one atmosphere (14.7 psig) of contained gas pressure. Less than that is typically a storage tank, even if there is some overpressure added by design. The rules for PVHO are invoked at 2 psig (13.8 kPa), per Section 1-2.1 "Application" of the ASME PVHO-1 code.  This lower threshold is due to the potential for serious injury if a person under pressure as low as 2 psig is rapidly decompressed. 
+Section 1-3 "Exclusions" specify nuclear reactor containments, aerospace cabins, caissons are not considered under the ASME PVHO-1 code.  This is because each of those types of occupied pressurized chambers  are under other jursidictions and therefore under other design codes. It is noted while "caissons" are under other applicable rules depending on the specific application, the Occupational Safety and Health Administration specifies the chambers in pressurized tunnel boring machines are under ASME PVHO-1 and any chamber used to decompress tunnel workers must meet ASME PVHO-1.
+
+
+== Titan submersible implosion ==
+In 2018, prior to the 2023 Titan submersible implosion, William Kohnen, the chair of the Marine Technology Society Submarine Committee, drafted a letter with 38 signatures to respond to OceanGate's public stance on not using existing codes and standards. The cause of the implosion is still under investigation, but it was noted the other nine submarines that could reach the depth of the wreck of the Titanic were all designed using recognised engineering codes.
+
+
+== References ==
+
+
+== External links ==
+ASME PVHO Committee homepage

data/en.wikipedia.org/wiki/Proactive_maintenance-0.md

@@ -0,0 +1,23 @@
+---
+title: "Proactive maintenance"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Proactive_maintenance"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:52:34.360234+00:00"
+instance: "kb-cron"
+---
+
+Proactive maintenance is the maintenance philosophy that supplants “failure reactive” with “failure proactive” by activities that avoid the underlying conditions that lead to machine faults and degradation.  Unlike predictive or preventive maintenance, proactive maintenance commissions corrective actions aimed at failure root causes, not failure symptoms.  Its central theme is to extend the life of machinery as opposed to
+
+making repairs when often nothing is wrong,
+accommodating failure as routine or normal, or
+detecting impending failure conditions followed by remediation.
+Proactive maintenance depends on rigorous machine inspection and condition monitoring.  In mechanical machinery it seeks to detect and eradicate failure root causes such as wrong lubricant, degraded lubricant, contaminated lubricant, botched repair, misalignment, unbalance and operator error.
+
+
+== See also ==
+Predictive maintenance
+
+
+== References ==

data/en.wikipedia.org/wiki/Proceedings_of_the_Institution_of_Mechanical_Engineers,_Part_B-0.md

@@ -0,0 +1,22 @@
+---
+title: "Proceedings of the Institution of Mechanical Engineers, Part B"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Proceedings_of_the_Institution_of_Mechanical_Engineers,_Part_B"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:52:35.571416+00:00"
+instance: "kb-cron"
+---
+
+The Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture is a peer-reviewed scientific journal that covers research on manufacturing engineering. The journal was established in 1989 and is published by SAGE Publications on behalf of the Institution of Mechanical Engineers.
+
+
+== Abstracting and indexing ==
+The journal is abstracted and indexed in Scopus and the Science Citation Index. According to the Journal Citation Reports, its 2013 impact factor is 0.661, ranking it 32nd out of 39 journals in the category "Engineering, Manufacturing" and 80th out of 126 journals in the category "Engineering, Mechanical".
+
+
+== References ==
+
+
+== External links ==
+Official website

data/en.wikipedia.org/wiki/Proceedings_of_the_Institution_of_Mechanical_Engineers,_Part_C-0.md

@@ -0,0 +1,22 @@
+---
+title: "Proceedings of the Institution of Mechanical Engineers, Part C"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Proceedings_of_the_Institution_of_Mechanical_Engineers,_Part_C"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:52:36.683587+00:00"
+instance: "kb-cron"
+---
+
+The Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science is a peer-reviewed scientific journal that covers the fundamentals of engineering science and its application to the solution of challenges and problems in engineering. The journal obtained its current name in 1989 when it was split off from the Proceedings of the Institution of Mechanical Engineers. It is published by SAGE Publications on behalf of the Institution of Mechanical Engineers. The editor-in-chief is J.W. Chew (University of Surrey).
+
+
+== Abstracting and indexing ==
+The 'journal is abstracted and indexed in Scopus and the Science Citation Index Expanded. According to the Journal Citation Reports, its 2020 impact factor is 1.762.
+
+
+== References ==
+
+
+== External links ==
+Official website

data/en.wikipedia.org/wiki/Proceedings_of_the_Institution_of_Mechanical_Engineers,_Part_E-0.md

@@ -0,0 +1,22 @@
+---
+title: "Proceedings of the Institution of Mechanical Engineers, Part E"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Proceedings_of_the_Institution_of_Mechanical_Engineers,_Part_E"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:52:37.875898+00:00"
+instance: "kb-cron"
+---
+
+The Proceedings of the Institution of Mechanical Engineers, Part E: Journal of Process Mechanical Engineering is a peer-reviewed scientific journal that covers research on the design and operation of process equipment. The journal was established in 1989 and is published by SAGE Publications on behalf of the Institution of Mechanical Engineers.
+
+
+== Abstracting and indexing ==
+The Journal of Process Mechanical Engineering is abstracted and indexed in Scopus and the Science Citation Index. According to the Journal Citation Reports, the journal has a 2021 impact factor of 1.606, ranking it 92nd out of 126 journals in the category "Engineering, Mechanical".
+
+
+== References ==
+
+
+== External links ==
+Official website

data/en.wikipedia.org/wiki/Proceedings_of_the_Institution_of_Mechanical_Engineers,_Part_G-0.md

@@ -0,0 +1,22 @@
+---
+title: "Proceedings of the Institution of Mechanical Engineers, Part G"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Proceedings_of_the_Institution_of_Mechanical_Engineers,_Part_G"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:52:39.045038+00:00"
+instance: "kb-cron"
+---
+
+The Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering is a peer-reviewed scientific journal that covers research in applied sciences and technology dealing with aircraft and spacecraft, as well as their support systems. The journal was established in 1989 and is published by SAGE Publications on behalf of the Institution of Mechanical Engineers.
+
+
+== Abstracting and indexing ==
+The journal is abstracted and indexed in Scopus and the Science Citation Index. According to the Journal Citation Reports, its 2013 impact factor is 0.454, ranking it 20th out of 27 journals in the category "Engineering, Aerospace" and 102nd out of 126 journals in the category "Engineering, Mechanical".
+
+
+== References ==
+
+
+== External links ==
+Official website

data/en.wikipedia.org/wiki/Proceedings_of_the_Institution_of_Mechanical_Engineers,_Part_I-0.md

@@ -0,0 +1,22 @@
+---
+title: "Proceedings of the Institution of Mechanical Engineers, Part I"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Proceedings_of_the_Institution_of_Mechanical_Engineers,_Part_I"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:52:40.244003+00:00"
+instance: "kb-cron"
+---
+
+The Proceedings of the Institution of Mechanical Engineers, Part I: Journal of Systems and Control Engineering is a peer-reviewed scientific journal established 1991 which covers systems and control studies. It is published by SAGE Publications on behalf of the Institution of Mechanical Engineers.
+
+
+== Abstracting and indexing ==
+The journal is abstracted and indexed in Scopus and the Science Citation Index Expanded. According to the Journal Citation Reports, its 2018 impact factor is 1.166.
+
+
+== References ==
+
+
+== External links ==
+Official website

data/en.wikipedia.org/wiki/Proceedings_of_the_Institution_of_Mechanical_Engineers,_Part_J-0.md

@@ -0,0 +1,22 @@
+---
+title: "Proceedings of the Institution of Mechanical Engineers, Part J"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Proceedings_of_the_Institution_of_Mechanical_Engineers,_Part_J"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:52:41.420392+00:00"
+instance: "kb-cron"
+---
+
+The Journal of Engineering Tribology, Part J of the Proceedings of the Institution of Mechanical Engineers (IMechE), is a peer-reviewed academic journal that publishes research on engineering science associated with tribology and its applications. The journal was first published in 1994 and is published by SAGE Publications on behalf of IMechE.
+
+
+== Abstracting and indexing ==
+The Journal of Engineering Tribology is abstracted and indexed in Scopus and the Science Citation Index. According to the Journal Citation Reports, its 2013 impact factor is 0.631, ranking it 81st out of 126 journals in the category "Engineering, Mechanical".
+
+
+== References ==
+
+
+== External links ==
+Official website

data/en.wikipedia.org/wiki/Proceedings_of_the_Institution_of_Mechanical_Engineers,_Part_K-0.md

@@ -0,0 +1,22 @@
+---
+title: "Proceedings of the Institution of Mechanical Engineers, Part K"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Proceedings_of_the_Institution_of_Mechanical_Engineers,_Part_K"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:52:42.616026+00:00"
+instance: "kb-cron"
+---
+
+The Proceedings of the Institution of Mechanical Engineers, Part K: Journal of Multi-body Dynamics is a quarterly peer-reviewed scientific journal that covers mechanical design and dynamic analysis of multi-body systems. The journal was established in 1999 and is published by SAGE Publications on behalf of the Institution of Mechanical Engineers.
+
+
+== Abstracting and indexing ==
+The journal is abstracted and indexed in Scopus and the Science Citation Index Expanded. According to the Journal Citation Reports, its 2013 impact factor is 0.415.
+
+
+== References ==
+
+
+== External links ==
+Official website

data/en.wikipedia.org/wiki/Proceedings_of_the_Institution_of_Mechanical_Engineers,_Part_L-0.md

@@ -0,0 +1,22 @@
+---
+title: "Proceedings of the Institution of Mechanical Engineers, Part L"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Proceedings_of_the_Institution_of_Mechanical_Engineers,_Part_L"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:52:43.824931+00:00"
+instance: "kb-cron"
+---
+
+The Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications is a peer-reviewed scientific journal that covers the usage and design of materials for application in engineering. The journal was established in 1999 and is published by SAGE Publications on behalf of the Institution of Mechanical Engineers.
+
+
+== Abstracting and indexing ==
+The journal is abstracted and indexed in Scopus and the Science Citation Index Expanded. According to the Journal Citation Reports, its 2013 impact factor is 0.746, ranking it 183rd out of 251 journals in the category "Materials Science, Multidisciplinary".
+
+
+== References ==
+
+
+== External links ==
+Official website

data/en.wikipedia.org/wiki/Proceedings_of_the_Institution_of_Mechanical_Engineers,_Part_M-0.md

@@ -0,0 +1,22 @@
+---
+title: "Proceedings of the Institution of Mechanical Engineers, Part M"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Proceedings_of_the_Institution_of_Mechanical_Engineers,_Part_M"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:52:44.982278+00:00"
+instance: "kb-cron"
+---
+
+The Proceedings of the Institution of Mechanical Engineers, Part M: Journal of Engineering for the Maritime Environment is a quarterly peer-reviewed scientific journal covering research on the design, production, and operation of engineering artefacts for the maritime environment. The journal covers subjects including naval architecture, marine engineering, offshore/ocean engineering, coastal engineering and port engineering. It was established in 2002 and is published by SAGE Publications on behalf of the Institution of Mechanical Engineers.
+
+
+== Abstracting and indexing ==
+The journal is abstracted and indexed in Scopus and the Science Citation Index Expanded. According to the Journal Citation Reports, the journal has a 2013 impact factor of 0.458.
+
+
+== References ==
+
+
+== External links ==
+Official website

data/en.wikipedia.org/wiki/Proceedings_of_the_Institution_of_Mechanical_Engineers,_Part_P-0.md

@@ -0,0 +1,22 @@
+---
+title: "Proceedings of the Institution of Mechanical Engineers, Part P"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Proceedings_of_the_Institution_of_Mechanical_Engineers,_Part_P"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:52:46.170858+00:00"
+instance: "kb-cron"
+---
+
+The Proceedings of the Institution of Mechanical Engineers, Part P: Journal of Sports Engineering and Technology is a peer-reviewed scientific journal that covers the development of novel sports apparel, footwear, and equipment; and the materials, instrumentation, and processes that make advances in sports possible. The journal was established in 2008 and is published by SAGE Publications on behalf of the Institution of Mechanical Engineers.
+
+
+== Abstracting and indexing ==
+The journal is abstracted and indexed in Scopus and the Science Citation Index Expanded. According to the Journal Citation Reports, its 2013 impact factor is 0.615.
+
+
+== References ==
+
+
+== External links ==
+Official website

data/en.wikipedia.org/wiki/Process_hazard_analysis-0.md

@@ -0,0 +1,24 @@
+---
+title: "Process hazard analysis"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Process_hazard_analysis"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:52:47.381102+00:00"
+instance: "kb-cron"
+---
+
+A process hazard analysis (PHA) (or process hazard evaluation) is an exercise for the identification of hazards of a process facility and the qualitative or semi-quantitative assessment of the associated risk. A PHA provides information intended to assist managers and employees in making decisions for improving safety and reducing the consequences of unwanted or unplanned releases of hazardous materials. A PHA is directed toward analyzing potential causes and consequences of fires, explosions, releases of toxic or flammable chemicals and major spills of hazardous chemicals, and it focuses on equipment, instrumentation, utilities, human actions, and external factors that might impact the process. It is one of the elements of OSHA's program for Process Safety Management.
+There are several methodologies that can be used to conduct a PHA, including checklists, hazard identification (HAZID) reviews, what-if reviews and SWIFT, hazard and operability studies (HAZOP), failure mode and effect analysis (FMEA), etc. PHA methods are qualitative or, at best, semi-quantitative in nature. A simple element of risk quantification is often introduced in the form of a risk matrix, as in preliminary hazard analysis (PreHA). The selection of the methodology to be used depends on a number of factors, including the complexity of the process, the length of time a process has been in operation and if a PHA has been conducted on the process before, and if the process is unique, or industrially common. Quantitative methods for risk assessment, such as layer-of-protection analysis (LOPA) or fault tree analysis (FTA) may be used after a PHA, if the PHA team could not reach a risk decision for a given scenario.
+In the United States, the use of PHAs is mandated as one of the elements of the Occupational Safety and Health Administration (OSHA)' process safety management regulation for the identification of risks involved in the design, operation, and modification of processes that handle highly hazardous chemicals.
+
+
+== See also ==
+Cyber PHA
+
+
+== References ==
+
+
+== Further reading ==
+Primatech (2017). Comparison of PHA Methods. Primatech. Retrieved 2023-06-24.

data/en.wikipedia.org/wiki/Projected_area-0.md

@@ -0,0 +1,60 @@
+---
+title: "Projected area"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Projected_area"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:52:48.569787+00:00"
+instance: "kb-cron"
+---
+
+Projected area is the area measurement of a three-dimensional object by projecting its silhouette on to an arbitrary plane. This is often used in mechanical engineering and architectural engineering related fields, especially for hardness testing, axial stress, wind pressures, and terminal velocity.
+The geometrical definition of a projected area is the rectilinear parallel projection of a surface of any shape onto a plane:
+
+  
+    
+      
+        
+          A
+          
+            projected
+          
+        
+        =
+        
+          ∫
+          
+            A
+          
+        
+        cos
+        ⁡
+        
+          β
+        
+        
+        d
+        A
+      
+    
+    {\displaystyle A_{\text{projected}}=\int _{A}\cos {\beta }\,dA}
+  
+
+where A is the original area, and 
+  
+    
+      
+        β
+      
+    
+    {\displaystyle \beta }
+  
+ is the angle between the normal to the local plane and the line of sight to the surface A. For basic shapes the results are listed in the table below.
+
+
+== See also ==
+Cross-sectional area
+Surface area
+
+
+== References ==

data/en.wikipedia.org/wiki/Projected_tolerance_zone-0.md

@@ -0,0 +1,15 @@
+---
+title: "Projected tolerance zone"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Projected_tolerance_zone"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:52:49.708567+00:00"
+instance: "kb-cron"
+---
+
+In geometric dimensioning and tolerancing, a projected tolerance zone is defined to predict the final dimensions and locations of features on a component or assembly subject to tolerance stack-up.
+
+
+== References ==
+ASME Y14.5M-1994 Dimensioning and Tolerancing

data/en.wikipedia.org/wiki/Pulse-swallowing_counter-0.md

@@ -0,0 +1,14 @@
+---
+title: "Pulse-swallowing counter"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Pulse-swallowing_counter"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:52:50.902968+00:00"
+instance: "kb-cron"
+---
+
+A pulse-swallowing counter is a component in an all-digital feedback system. The divider produces one output pulse for every N counts (N  is usually a power of 2) when not swallowing, and per N+1 pulses when the 'swallow' signal is active.  The overall pulse-swallowing system is used as part of a fractional-N frequency divider. The overall pulse-swallowing system cancels beatnotes created when switching between N, N+1, or N−1 in a fractional-N synthesizer.
+
+
+== References ==

data/en.wikipedia.org/wiki/Radial_stress-0.md

@@ -0,0 +1,273 @@
+---
+title: "Radial stress"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Radial_stress"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:52:52.097276+00:00"
+instance: "kb-cron"
+---
+
+Radial stress is stress toward or away from the central axis of a component.
+
+
+== Pressure vessels ==
+The walls of pressure vessels generally undergo triaxial loading. For cylindrical pressure vessels, the normal loads on a wall element are longitudinal stress, circumferential (hoop) stress and radial stress.
+The radial stress for a thick-walled cylinder is equal and opposite to the gauge pressure on the inside surface, and zero on the outside surface. The circumferential stress and longitudinal stresses are usually much larger for pressure vessels, and so for thin-walled instances, radial stress is usually neglected.
+
+
+== Formula ==
+The radial stress for a thick walled pipe at a point 
+  
+    
+      
+        r
+      
+    
+    {\displaystyle r}
+  
+ from the central axis is given by
+
+  
+    
+      
+        
+          σ
+          
+            r
+          
+        
+        (
+        r
+        )
+        =
+        
+          
+            
+              
+                p
+                
+                  i
+                
+              
+              
+                r
+                
+                  i
+                
+                
+                  2
+                
+              
+              −
+              
+                p
+                
+                  o
+                
+              
+              
+                r
+                
+                  o
+                
+                
+                  2
+                
+              
+            
+            
+              
+                r
+                
+                  o
+                
+                
+                  2
+                
+              
+              −
+              
+                r
+                
+                  i
+                
+                
+                  2
+                
+              
+            
+          
+        
+        +
+        
+          
+            
+              
+                r
+                
+                  i
+                
+                
+                  2
+                
+              
+              
+                r
+                
+                  o
+                
+                
+                  2
+                
+              
+              (
+              
+                p
+                
+                  o
+                
+              
+              −
+              
+                p
+                
+                  i
+                
+              
+              )
+            
+            
+              
+                r
+                
+                  2
+                
+              
+              (
+              
+                r
+                
+                  o
+                
+                
+                  2
+                
+              
+              −
+              
+                r
+                
+                  i
+                
+                
+                  2
+                
+              
+              )
+            
+          
+        
+         
+      
+    
+    {\displaystyle \sigma _{r}(r)={\frac {p_{i}r_{i}^{2}-p_{o}r_{o}^{2}}{r_{o}^{2}-r_{i}^{2}}}+{\frac {r_{i}^{2}r_{o}^{2}(p_{o}-p_{i})}{r^{2}(r_{o}^{2}-r_{i}^{2})}}\ }
+  
+
+where 
+  
+    
+      
+        
+          r
+          
+            i
+          
+        
+      
+    
+    {\displaystyle r_{i}}
+  
+ is the inner radius, 
+  
+    
+      
+        
+          r
+          
+            o
+          
+        
+      
+    
+    {\displaystyle r_{o}}
+  
+ is the outer radius, 
+  
+    
+      
+        
+          p
+          
+            i
+          
+        
+      
+    
+    {\displaystyle p_{i}}
+  
+ is the inner absolute pressure and 
+  
+    
+      
+        
+          p
+          
+            o
+          
+        
+      
+    
+    {\displaystyle p_{o}}
+  
+ is the outer absolute pressure.  Maximum radial stress occurs when 
+  
+    
+      
+        r
+        =
+        
+          r
+          
+            i
+          
+        
+      
+    
+    {\displaystyle r=r_{i}}
+  
+ (at the inside surface) and is equal to gauge pressure, or 
+  
+    
+      
+        
+          p
+          
+            i
+          
+        
+        −
+        
+          p
+          
+            o
+          
+        
+      
+    
+    {\displaystyle p_{i}-p_{o}}
+  
+.
+
+
+== References ==

data/en.wikipedia.org/wiki/Rahab_Institute-0.md

@@ -0,0 +1,14 @@
+---
+title: "Rahab Institute"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Rahab_Institute"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:52:53.267861+00:00"
+instance: "kb-cron"
+---
+
+The Rahab Institute is a subsidiary of Khatam al-Anbiya Construction Headquarters in Iran. It is blacklisted by the United States Department of the Treasury, the United Nations, and the European Union.
+
+
+== References ==

data/en.wikipedia.org/wiki/Railway_engineering-0.md

@@ -0,0 +1,70 @@
+---
+title: "Railway engineering"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Railway_engineering"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:52:54.459725+00:00"
+instance: "kb-cron"
+---
+
+Railway engineering is the discipline of engineering which concerns the design, construction, operation, and maintenance of railways and rail transportation systems. It includes a wide range of engineering disciplines, including (but not limited to) civil engineering, computer engineering, electrical engineering, mechanical engineering, industrial engineering and production engineering.
+
+
+== History ==
+In the seventeenth and eighteenth century, the first railways were built for the horse-drawn trains of wagons in collieries and quarries, with the first materials consisting of stone slabs and timber baulks. However, the rails were weary with carrying heavier loads.
+During the Industrial Revolution, cast iron were added to the railway tracks to reduce the wear on the wooden baulks, which evolved further into iron edge rails, which enabled to flanged wheels' utility.
+In the early nineteenth century, as the locomotives came into the picture, wrought iron rails and steel rails developed to support heavy axle loads without longitudinal timbers. With the advent of the railway, a need arose for specialized engineers capable of dealing with the unique problems associated with railway engineering. As the railways expanded and became a major part in logistics, more engineers became involved in the field, probably the most notable in Britain being Richard Trevithick, George Stephenson and Isambard Kingdom Brunel.
+
+
+== Subfields ==
+Mechanical engineering
+Electrical engineering
+Command, control & railway signalling
+SCADA
+Network design
+Civil engineering
+Permanent way engineering
+Railway systems engineering
+Railway signalling
+Fare collection
+CCTV
+Public address
+Intrusion detection
+Access control
+Computer engineering
+Systems integration
+
+
+== Professional organisations ==
+In Australia and New Zealand: the Railway Technical Society of Australasia (RTSA)
+In the UK: the Railway Division of the Institution of Mechanical Engineers (IMechE)
+In the US: the American Railway Engineering and Maintenance-of-Way Association (AREMA)
+In the Philippines: the Philippine Railway Engineers' Association, (PREA) Inc.
+Worldwide: the Institute of Railway Signal Engineers (IRSE)
+
+
+== See also ==
+
+
+=== Glossary ===
+Light rail systems
+On-track plant
+Train control systems
+Cab signalling
+Rolling resistance
+Curve resistance
+Wheel–rail interface
+Hunting oscillation
+Energy electrification
+Third rail
+Fourth rail
+Overhead contact system
+
+
+== External links ==
+Institution of Mechanical Engineers - Railway Division
+AAR
+
+
+== References ==

data/en.wikipedia.org/wiki/Rayleigh_Still-0.md

@@ -0,0 +1,14 @@
+---
+title: "Rayleigh Still"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Rayleigh_Still"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:52:55.638005+00:00"
+instance: "kb-cron"
+---
+
+In distillation, a Rayleigh Still is a separation process where a feed stream is charged and withdrawn batch-wise with a separate stream fed and removed continuously.  It is also known as a Rayleigh Distillation.  It consists of a single stage distillation where the batch-charged phase is well mixed during operation.  This was developed originally by Lord Rayleigh in 1902.
+
+
+== References ==

data/en.wikipedia.org/wiki/Reach-in_oven-0.md

@@ -0,0 +1,16 @@
+---
+title: "Reach-in oven"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Reach-in_oven"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:52:56.817921+00:00"
+instance: "kb-cron"
+---
+
+Reach-in ovens are meant for different industrial applications that may need uniform temperature throughout. The ovens normally use horizontal re-circulating air to ensure the uniform temperature, and can use fans that circulate air, creating the airflow. Reach-in ovens can be used in numerous production and laboratory applications, including curing, drying, sterilizing, aging, and other process-critical applications.
+Reach-in ovens are considered a type of industrial batch oven. Other types of batch ovens are bench/laboratory, burn in, laboratory, walk in/truck in, and clean process.
+
+
+== External links ==
+National Fire Protection Association

data/en.wikipedia.org/wiki/Rebar_detailing-0.md

@@ -0,0 +1,19 @@
+---
+title: "Rebar detailing"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Rebar_detailing"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:52:57.980422+00:00"
+instance: "kb-cron"
+---
+
+Rebar detailing is the discipline of preparing 'shop/placing' or 'fabrication' drawings or shop drawings of steel reinforcement for construction.
+Engineers prepare 'design drawings' that develop required strengths by applying rebar size, spacing, location, anchoring details and lap and/or splicing of steel. The depth of concrete cover is also standard part of rebar detail drawing.
+By contrast, 'shop/placing drawings' or 'fabrication drawings' apply the intent of the 'design drawings' for the ironworker. These designs specify the quantity, description, placement, bending shapes with dimensions and laps of the reinforcing steel. Various applications are used to produce bar bending schedules which can be directly fed into CNC machines that cut and bend the rebar to the desired shapes.
+The fabrication of the bars is scheduled and the placing/fixing sequence indicated, adding the elements required to support those bars during construction.
+'Shop/placing drawings' are submitted to the engineer for review of compliance with design drawings before construction can proceed. These drawings must be detailed using the ACI & CRSI Specifications (United States), ACI & RSIC Specifications (Canada), or BS Specifications (United Kingdom).
+Rebar detailing is usually assigned to in-house rebar fabricators or rebar detailing companies. The great majority of rebar detailing companies are stationed in The Middle East and India. The salary of a rebar detailer in the United States ranges from $45,000 to $75,000, but outsourcing is common due to substantially lower wages overseas.
+
+
+== References ==

data/en.wikipedia.org/wiki/Reciprocating_motion-0.md

@@ -0,0 +1,36 @@
+---
+title: "Reciprocating motion"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Reciprocating_motion"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:52:59.161790+00:00"
+instance: "kb-cron"
+---
+
+Reciprocating motion, also called reciprocation, is a repetitive up-and-down or back-and-forth linear motion. It is found in a wide range of mechanisms, including reciprocating engines and pumps. The two opposite motions that comprise a single reciprocation cycle are called strokes.
+A crank can be used to convert into reciprocating motion, or conversely turn reciprocating motion into circular motion.
+For example, inside an internal combustion engine (a type of reciprocating engine),  the expansion of burning fuel in the cylinders periodically pushes the piston down, which, through the connecting rod, turns the crankshaft. The continuing rotation of the crankshaft drives the piston back up, ready for the next cycle. The piston moves in a reciprocating motion, which is converted into the 
+circular motion of the crankshaft, which ultimately propels the vehicle or does other useful work. 
+The reciprocating motion of a pump piston is close to but different from, sinusoidal simple harmonic motion. Assuming the wheel is driven at a perfect constant rotational velocity, the point on the crankshaft which connects to the connecting rod rotates smoothly at a constant velocity in a circle. Thus, the displacement of that point is indeed exactly sinusoidal by definition.  However, during the cycle, the angle of the connecting rod changes continuously, so the horizontal displacement of the "far" end of the connecting rod (i.e., connected to the piston) differs slightly from sinusoidal. Additionally, if the wheel is not spinning with perfect constant rotational velocity, such as in a steam locomotive starting up from a stop, the motion will be even less sinusoidal. 
+
+
+== See also ==
+Oscillation – Repetitive variation of some measure about a central value
+Stroboscope – Instrument used to study object movement
+Reciprocating saw – Type of machine powered saw
+Reciprocating engine – Engine utilising one or more reciprocating pistons
+Rotary reciprocating saw – Type of mechanical saw
+Agitation – Device or mechanism which shakes or stirs something
+Scotch yoke – Mechanism to convert between rotational and reciprocating motion
+Crank – Arm attached to a rotating shaft for circular motion
+Crankshaft – Mechanism for converting reciprocating motion to rotation
+Swashplate – Mechanism to convert between reciprocating and rotary motion
+Trip hammer – Type of blacksmithing tool
+Slider-crank linkage – Mechanism for converting rotary motion into linear motion
+Straight line mechanism – Mechanisms generating real or approximate straight line motionPages displaying short descriptions of redirect targets
+Reciprocating compressor – Device used to pump gases at high pressure
+Sun and planet gear – Type of gear used in early beam engines
+
+
+== References ==

data/en.wikipedia.org/wiki/Regulator_(automatic_control)-0.md

@@ -0,0 +1,30 @@
+---
+title: "Regulator (automatic control)"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Regulator_(automatic_control)"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:53:00.338824+00:00"
+instance: "kb-cron"
+---
+
+In automatic control, a regulator is a device which has the function of maintaining a designated characteristic. It performs the activity of managing or maintaining a range of values in a machine. The measurable property of a device is managed closely by specified conditions or an advance set value; or it can be a variable according to a predetermined arrangement scheme. It can be used generally to connote any set of various controls or devices for regulating or controlling items or objects.
+Examples are a voltage regulator (which can be a transformer whose voltage ratio of transformation can be adjusted, or an electronic circuit that produces a defined voltage), a pressure regulator, such as a diving regulator, which maintains its output at a fixed pressure lower than its input, and a fuel regulator (which controls the supply of fuel).
+Regulators can be designed to control anything from gases or fluids, to light or electricity. Speed can be regulated by electronic, mechanical, or electro-mechanical means. Such instances include; 
+
+Electronic regulators as used in modern railway sets where the voltage is raised or lowered to control the speed of the engine
+Mechanical systems such as valves as used in fluid control systems. Purely mechanical pre-automotive systems included such designs as the Watt centrifugal governor whereas modern systems may have electronic fluid speed sensing components directing solenoids to set the valve to the desired rate.
+Complex electro-mechanical speed control systems used to maintain speeds in modern cars (cruise control) - often including hydraulic components,
+An aircraft engine's constant speed unit changes the propeller pitch to maintain engine speed.
+
+
+== Bibliography ==
+Smith, Ed Sinclair (1944). Automatic Control Engineering. McGraw-Hill.
+Popov, E. P. (2014). The Dynamics of Automatic Control Systems. Pergamon. ISBN 9781483184623.
+Wang, Wego, ed. (2013). Mechatronics and Automatic Control Systems: Proceedings of the 2013 International Conference on Mechatronics and Automatic Control Systems (ICMS2013). Springer International Publishing. ISBN 9783319012735.
+
+
+== See also ==
+Controller (control theory)
+Governor (device)
+Process control

data/en.wikipedia.org/wiki/Rejlers-0.md

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+---
+title: "Rejlers"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Rejlers"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:53:01.517372+00:00"
+instance: "kb-cron"
+---
+
+Rejlers is one of the largest engineering consultancy firms in the Nordic region. Rejlers has 2400 employees in technology areas such as energy, industry, infrastructure, real estate and telecom. Rejlers have representation in Sweden, Finland, Norway and the United Arab Emirates. In 2019, the company had a turnover of 2.6 billion SEK and its class B share is listed on Nasdaq Stockholm.
+
+
+== External links ==
+Company's website

data/en.wikipedia.org/wiki/Reliability,_availability,_maintainability_and_safety-0.md

@@ -0,0 +1,22 @@
+---
+title: "Reliability, availability, maintainability and safety"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Reliability,_availability,_maintainability_and_safety"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:53:03.867307+00:00"
+instance: "kb-cron"
+---
+
+In engineering, reliability, availability, maintainability and safety (RAMS) is used to characterize a product or system:
+
+Reliability: Ability to perform a specific function and may be given as design reliability or operational reliability
+Availability: Ability to keep a functioning state in the given environment
+Maintainability: Ability to be timely and easily maintained (including servicing, inspection and check, repair and/or modification)
+Safety: Ability not to harm people, the environment, or any assets during a whole life cycle.
+
+
+== See also ==
+
+
+== References ==

data/en.wikipedia.org/wiki/Reliability_Engineering_and_Risk_Analysis-0.md

@@ -0,0 +1,14 @@
+---
+title: "Reliability Engineering and Risk Analysis"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Reliability_Engineering_and_Risk_Analysis"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:53:02.671863+00:00"
+instance: "kb-cron"
+---
+
+Reliability Engineering and Risk Analysis: A Practical Guide (ISBN 9781498745871) is a textbook on techniques for analysis of reliability and risk, written by Mohammad Modarres, Mark Kaminskiy, and Vasiliy Krivtsov.
+
+
+== References ==

data/en.wikipedia.org/wiki/Repairable_component-0.md

@@ -0,0 +1,29 @@
+---
+title: "Repairable component"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Repairable_component"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:53:05.085638+00:00"
+instance: "kb-cron"
+---
+
+A repairable component is a component of a finished good that can be designated for repair.
+
+
+== Overview ==
+Repairable components tend to be more expensive than non-repairable components (consumables). This is because for items that are inexpensive to procure, it is often more cost-effective not to maintain (repair) them. Repair costs can be expensive, including costs for the labor for the removal the broken or worn out part (described as unserviceable), cost of replacement with a working (serviceable) from inventory, and also the cost of the actual repair, including possible shipping costs to a repair vendor.
+At maintenance facilities, such as might be found at main operating bases, inventory is controlled by site personnel. Maintenance personnel will formally "turn-in" unserviceable items for repair, receiving a funding credit in the process. These "turn-ins" will be fixed, reconditioned, or replaced. Maintenance personnel can also be issued repaired or new items back from inventory. These processes are assisted by automated logistics management systems.
+In the Navy/Marine Corps supply system repairable items are identified with certain two character cognizance symbols (COGs) and one character Material Control Codes (MCCs).
+In United States Marine Corps Aviation, repairables are managed by the Repairables Management Division of the Aviation Supply Department.
+In the United States Air Force, repairables can be identified by their ERRC designation or SMR code.
+
+
+== See also ==
+
+Level of repair analysis
+Repairability
+Right to repair
+
+
+== References ==

data/en.wikipedia.org/wiki/Resonant_converter-0.md

@@ -0,0 +1,29 @@
+---
+title: "Resonant converter"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Resonant_converter"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:53:06.253796+00:00"
+instance: "kb-cron"
+---
+
+A resonant converter is a type of electric power converter that contains a network of inductors and capacitors called a resonant tank, tuned to resonate at a specific frequency. They find applications in electronics, in integrated circuits.
+There are multiple types of resonant converter:
+
+Series resonant converter
+Parallel resonant converter
+Class E resonant converter
+Class E resonant rectifier
+Zero-voltage switching resonant converter
+Zero-current switching resonant converter
+Two-quadrant ZVS resonant converter
+Resonant DC-link inverter
+
+
+== See also ==
+Inverter
+Switched-mode power supply
+
+
+== References ==

data/en.wikipedia.org/wiki/Retrogression_heat_treatment-0.md

@@ -0,0 +1,15 @@
+---
+title: "Retrogression heat treatment"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Retrogression_heat_treatment"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:53:07.455128+00:00"
+instance: "kb-cron"
+---
+
+Retrogression heat treatment (RHT) is a heat treatment process that rapidly heat treats age-hardenable aluminum alloys. Mainly induction heating is used for RHT. In the past, it was mainly used for 6061 and 6063 aluminum alloys. Therefore, forming of complex shapes is possible, without creating damages like cracks. Even hard tempers (for example -T6) can be formed easily after subjecting these alloys to RHT.
+
+
+== References ==
+M Koç (25 April 2008). Hydroforming for Advanced Manufacturing. Elsevier. p. 253. ISBN 978-1-84569-441-8.

data/en.wikipedia.org/wiki/Reverse_curve-0.md

@@ -0,0 +1,22 @@
+---
+title: "Reverse curve"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Reverse_curve"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:53:08.633704+00:00"
+instance: "kb-cron"
+---
+
+In civil engineering, a reverse curve (or "S" curve) is a section of the horizontal alignment of a highway or rail route in which a curve to the left or right is followed immediately by a curve in the opposite direction.
+On highways in the United States reverse curves are often announced by the posting of a W1-4L sign (left–right reverse curve) or a W1-4R sign (right–left reverse curve), as called for in the Manual on Uniform Traffic Control Devices.
+On rail routes, reverse curves can cause buffer-locking. On the Northeast Corridor in the United States, these also hinder the development of  high-speed rail.
+
+
+== See also ==
+S bridge
+Road curve
+Track geometry
+
+
+== References ==

data/en.wikipedia.org/wiki/Rigid_frame-0.md

@@ -0,0 +1,27 @@
+---
+title: "Rigid frame"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Rigid_frame"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:53:09.793298+00:00"
+instance: "kb-cron"
+---
+
+In structural engineering, a rigid frame is the load-resisting skeleton constructed with straight or curved members interconnected by predominantly rigid connections, which resist movements induced at the joints of members. Its members can resist bending moment, shear, and axial loads.
+The two common assumptions as to the behavior of a building frame are (1) that its beams are free to rotate at their connections or (2) that its members are so connected that the angles they make with each other do not change under load.  Frameworks with connections of intermediate stiffness will be intermediate between these two extremes. They are commonly called semirigid frames. The AISC specifications recognize three basic frame types: rigid frame, simple frame, and partially restrained frame.
+
+
+== AISC standard ==
+The AISC Steel Specification Commentary on Section B3 provides guidance for the classification of a connection in terms of its rigidity. The secant stiffness of the connection Ks is taken as an index property of connection stiffness. Specifically,
+
+The secant stiffness of the connection is compared to the rotational stiffness of the connected member as follows, in which L and EI are the length and bending rigidity, respectively, of the beam.
+
+If KsL/EI ≥ 20, it is acceptable to consider the connection to be fully restrained (in other words, able to maintain the angles between members).  If KsL/EI ≤ 2, it is acceptable to consider the connection to be simple (in other words, it rotates without developing moment).  Connections with stiffnesses between these two limits are partially restrained and the stiffness, strength and ductility of the connection must be considered in the design.
+
+
+== Notes ==
+
+
+== References ==
+Specification for Structural Steel Buildings (ANSI/AISC 360-16) (PDF). American Institute of Steel Construction (AISC). July 7, 2016. Retrieved 2018-01-27.

data/en.wikipedia.org/wiki/Rock_shed-0.md

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+---
+title: "Rock shed"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Rock_shed"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:53:12.128380+00:00"
+instance: "kb-cron"
+---
+
+A rock shed is a civil engineering structure used in mountainous areas where rock slides and land slides create highway closure problems. A rock shed is built over a roadway that is in the path of the slide.  They are equally used to protect railroads.  They are usually designed as a heavy reinforced concrete covering over the road, protecting the surface and vehicles from damage due to the falling rocks with a sloping surface to deflect slip material beyond the road, however an alternative is to include an impact-absorbing layer above the ceiling. A further use of this type of structure may be seen protecting the A4 road; although constructed primarily to alleviate risk from falling rocks from a limestone seam it also serves to protect against objects or persons falling from the Clifton Suspension Bridge where the height differential of approximately 70 metres from the bridge to the bottom of the Avon Gorge would give sufficient kinetic energy to even a relatively small item to cause injury on impact.
+
+
+== Examples of rock sheds ==
+
+A4 road where it passes under the Clifton Suspension Bridge, Bristol, England, constructed in 1980
+California State Route 1 at Pitkins Curve, just north of Limekiln State Park, constructed in 2014
+Ferguson Rock Shed, to rectify a closure of California State Route 140 by a landslide in 2006, completion expected in the early-2030s
+Second East–West Highway, near the Perak-Pahang border, currently under construction.
+
+
+== External links ==
+ Media related to Rock sheds at Wikimedia Commons
+
+
+== See also ==
+Avalanche dam
+Rock shelter
+Snow shed
+
+
+== References ==

data/en.wikipedia.org/wiki/Rockware_Glass-0.md

@@ -0,0 +1,18 @@
+---
+title: "Rockware Glass"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Rockware_Glass"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:53:13.314888+00:00"
+instance: "kb-cron"
+---
+
+Rockware Glass is a UK company manufacturing glass containers.
+The company has a works at Doncaster, South Yorkshire, Worksop, Nottinghamshire, Knottingley West Yorkshire and Irvine, Scotland. Rockware became part of Ardagh Glass Group in 2006.
+Rockware's former works by the Grand Union Canal in Greenford, London, were developed from W.A.Bailey's glassworks, founded in 1900, and Purex lead works. By 1959 Rockware employed 1,220 people on a 14 hectare (35 acre) site.
+In 1968, Rockware acquired the former Forster's Glass Company of St Helens, Lancashire.
+The Greenford works closed in 1973 and is commemorated by Rockware Avenue.
+
+
+== References ==

data/en.wikipedia.org/wiki/Roll-to-roll_processing-0.md

@@ -0,0 +1,50 @@
+---
+title: "Roll-to-roll processing"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Roll-to-roll_processing"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:53:14.499658+00:00"
+instance: "kb-cron"
+---
+
+In the field of electronic devices, roll-to-roll processing, also known as web processing, reel-to-reel processing or R2R, is the process of creating electronic devices on a roll of flexible plastic, metal foil, or flexible glass. In other fields predating this use, it can refer to any process of applying coating, printing, or performing other processes starting with a roll of a flexible material and re-reeling after the process to create an output roll. These processes, and others such as sheeting, can be grouped together under the general term converting. When the rolls of material have been coated, laminated or printed they can be subsequently slit to their finished size on a slitter rewinder.
+
+
+== In electronic devices ==
+Large circuits made with thin-film transistors and other devices can be patterned onto these large substrates, which can be up to a few metres wide and 50 km (31 mi) long.  Some of the devices can be patterned directly, much like an inkjet printer deposits ink.  For most semiconductors, however, the devices must be patterned using photolithography techniques.
+
+Roll-to-roll processing of large-area electronic devices reduces manufacturing cost.  Most notable would be solar cells, which are still prohibitively expensive for most markets due to the high cost per unit area of traditional bulk (mono- or polycrystalline) silicon manufacturing.  Other applications could arise which take advantage of the flexible nature of the substrates, such as electronics embedded into clothing, large-area flexible displays, and roll-up portable displays.
+
+
+=== LED (Light-Emitting Diode) ===
+Inorganic LED – Flexible LED is commonly made into 25, 50, 100 m, or even longer strips using a roll-to-roll process. A long neon LED tube is using such a long flexible strip and encapsulated with PVC or silicone diffusing encapsulation.
+Organic LED (OLED) – OLED for foldable phone screen is adopting roll-to-roll processing technology.
+
+
+=== Thin-film cells ===
+A crucial issue for a roll-to-roll thin-film cell production system is the deposition rate of the microcrystalline layer, and this can be tackled using four approaches:
+
+very high frequency plasma-enhanced chemical vapour deposition (VHF-PECVD)
+microwave (MW)-PECVD
+hot-wire chemical vapour deposition (hot-wire CVD)
+the use of ultrasonic nozzles in an in-line process
+
+
+== In electrochemical devices ==
+Roll-to-roll processing has been used in the manufacture of electrochemical devices such as batteries, supercapacitors, fuel cells, and water electrolyzers. Here, the roll-to-roll processing is utilized for electrode manufacturing and is the key to reducing manufacturing cost through stable production of electrodes on various film substrates such as metal foils, membranes, diffusion media, and separators.
+
+
+== See also ==
+
+Amorphous silicon
+Low-cost solar cell
+Printed electronics
+Roll slitting
+Rolling (metalworking)
+Thin-film solar cell
+Web manufacturing
+Tape automated bonding, TAB
+
+
+== References ==

data/en.wikipedia.org/wiki/Rolled_plate_glass-0.md

@@ -0,0 +1,14 @@
+---
+title: "Rolled plate glass"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Rolled_plate_glass"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:53:15.687065+00:00"
+instance: "kb-cron"
+---
+
+Rolled plate is a type of industrially produced glass. It was invented and patented by James Hartley circa 1847. Rolled-plate glass is used architecturally; in the mid-19th century, uses included roofing railway stations and greenhouses.
+
+
+== References ==

data/en.wikipedia.org/wiki/Rotary_transfer_machine-0.md

@@ -0,0 +1,23 @@
+---
+title: "Rotary transfer machine"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Rotary_transfer_machine"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:53:16.898077+00:00"
+instance: "kb-cron"
+---
+
+A rotary transfer machine is a machine tool, typically for metal working by machining, comprising a large indexing table with machining stations surrounding the table. Such rotary transfer machines are used for producing a large number of parts in fairly short cycle times.
+
+
+== Operation ==
+In rotary transfer machines, the workpieces are located and clamped in pallet type fixtures that are indexed in a circular path. During one cycle, sequential machining operations are performed simultaneously on the workpieces. The indexed table turns vertically or horizontally, and its movement could be continuous or intermittent. As the indexing table turns, the subsequent machining operation is repeated on the workpiece which was just machined by the previous station. This design combines automated part feed with simultaneous operations, enabling rapid completion of parts.
+
+
+== Applications ==
+Rotary transfer machines are commonly used for the mass-production of metal parts in the automotive industry and for pneumatic and hydraulic fittings. The parts can range from simple to complex, depending on the layout of the machining tool, which is often custom-designed for the manufacturing of a single part or family of parts. Rotary arrangement presents a compact arrangement that saves floor space. The annual production capacity of one rotary transfer machine can range from 100'000 units to tens of millions of units.
+Rotary transfer machines can generally cope with all standard machining operations like turning, milling, drilling, reaming, threading, recessing, marking, deburring, etc... for sizes ranging more or less from a fingernail up to a backpack. 
+
+
+== References ==

data/en.wikipedia.org/wiki/Rubb_hall-0.md

@@ -0,0 +1,21 @@
+---
+title: "Rubb hall"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Rubb_hall"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:53:18.091679+00:00"
+instance: "kb-cron"
+---
+
+A Rubb Hall is a commercial name for particularly large, relocatable tent-like structure often used in situations of emergency (e.g. humanitarian) and temporary industry (e.g. construction projects).  The name derives from Rubb Building Systems, and Hall Engineering of Bergen Norway, manufacturers of this kind of structure. Other types of similar structure include HAGUHALL.
+Rubb Halls are usually made of aluminium frames, with steel tension wires and polyester skins. They typically come in sections so the length can be determined by the number of sections employed. A common standard size is an area of 200 square metres. Doors at either end are made from the same material as the walls, and are drawn back like curtains. More secure and longer lasting structures include Flospan - frameless steel structures.
+Various specialised modifications are possible, including the fitting of artificial ceilings inside, together with doors in end walls, to facilitate heating. It is also not unheard of to have a frame erected inside to provide a second floor.
+In humanitarian aid situations, Rubb Halls are often used as warehouses for items such as food and medicine. They are also used for temporary emergency shelter for large numbers of people, and as spaces for activities such as person registration to take place under shelter.
+
+
+== See also ==
+Nissen hut
+
+
+== References ==

data/en.wikipedia.org/wiki/Rushton_turbine-0.md

@@ -0,0 +1,15 @@
+---
+title: "Rushton turbine"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Rushton_turbine"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:53:19.254175+00:00"
+instance: "kb-cron"
+---
+
+The Rushton turbine or Rushton disc turbine is a radial flow impeller used for many mixing applications (commonly for gas dispersion applications) in process engineering and was invented by John Henry Rushton. The design is based on a flat horizontal disk, with flat, vertically mounted blades that are usually six or eight in number. Recent innovations include the use of concave or semi-circular blades.
+It is preferred in the fermentation and bioprocessing industries, because it can very efficiently facilitate gas dispersion, and it can create independent large-scale circulation loops for better homogenisation. This is because it can effectively handle non-Newtonian fluids, such as solid suspensions. In these cases, the diameter of the turbine is usually between a third to half of that of the cylindrical tank. 
+
+
+== References ==

data/en.wikipedia.org/wiki/SAE_J306-0.md

@@ -0,0 +1,14 @@
+---
+title: "SAE J306"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/SAE_J306"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:53:20.444839+00:00"
+instance: "kb-cron"
+---
+
+SAE J306 is a standard that defines the viscometric properties of automotive gear oils. It is maintained by SAE International. Key parameters for this standard are the kinematic viscosity of the gear oil, the maximum temperature at which the oil has a viscosity of 150,000 cP, and a measure of its shear stability through the KRL test.
+
+
+== References ==

data/en.wikipedia.org/wiki/SAFE_Building_System-0.md

@@ -0,0 +1,22 @@
+---
+title: "SAFE Building System"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/SAFE_Building_System"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:53:21.644545+00:00"
+instance: "kb-cron"
+---
+
+The SAFE Building System, also known as the SAFE Foundation System, is a way to build in flood zones and coastal areas, developed by architect and inventor Greg Henderson and his team at Arx Pax Labs, Inc. It is designed to float buildings, roadways, and utilities in a few feet of water.  The self-adjusting floating environment draws from existing technologies used to float concrete bridges and runways such as Washington's SR 520 and Japan's Mega-Float. It also absorbs the shock of earthquakes, allowing buildings and their related communities to remain stable. Arx Pax is working with Republic of Kiribati and Pacific Rising to solve for sustainable development challenges associated with rising sea levels.
+Arx Pax, the company involved in this technology has proposed building a “floating village” project in north San Jose's Alviso hamlet, deploying a group of pontoons beneath the buildings to protect the development from floods and earthquakes.
+Originally developed for earthquakes as an alternative to Base Isolation the floating foundation decouples the structure from the earth with a simple patented method consisting of three parts. According to the patent, "Three part foundation systems can include a containment vessel, which constrains a buffer medium to an area above the containment vessel, and a construction platform. A building can be built on the construction platform. In a particular embodiment, during operation, the construction platform and structures built on the construction platform can float on the buffer medium. In an earthquake, a construction platform floating on a buffer medium may experience greatly reduced shear forces. In a flood, a construction platform floating on a buffer medium can be configured to rise as water levels rise to limit flood damage."
+
+
+== See also ==
+Sustainable development
+Evergreen Point Floating Bridge
+Very large floating structure
+
+
+== References ==

data/en.wikipedia.org/wiki/SDEF-0.md

@@ -0,0 +1,14 @@
+---
+title: "SDEF"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/SDEF"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:53:26.301274+00:00"
+instance: "kb-cron"
+---
+
+The Standard Data Exchange Format (SDEF) provides a proprietary protocol to exchange project planning and progress data between scheduling systems and project management software. It is used by the United States Army Corps of Engineers USACE (or Corps Of Engineers, COE) in their project management and network analysis systems (NAS). The USACE publications library includes the exact SDEF specification in PDF format.
+
+
+== References ==

data/en.wikipedia.org/wiki/SPE_John_Franklin_Carll_Award-0.md

@@ -0,0 +1,15 @@
+---
+title: "SPE John Franklin Carll Award"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/SPE_John_Franklin_Carll_Award"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:53:45.781720+00:00"
+instance: "kb-cron"
+---
+
+SPE John Franklin Carll Award is one of the Society of Petroleum Engineers' (SPE) highest prizes, established in 1956. It recognizes contributions of applications of engineering practices in petroleum development and recovery. The prize is named in honor of John Franklin Carll, a geologist of the 19th century, who was involved with writing reports on oil and gas surveys. 
+
+
+== External links ==
+http://www.spe.org/about/honors/intl_awards/tech_awards/carll_award.php

data/en.wikipedia.org/wiki/SQEP-0.md

@@ -0,0 +1,24 @@
+---
+title: "SQEP"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/SQEP"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:53:49.392447+00:00"
+instance: "kb-cron"
+---
+
+SQEP is an acronym for suitably qualified and experienced person.
+The term is notably used in the Defense, Aerospace, and Intelligence sectors. 
+UK nuclear power industry, see for example this safety management audit report from the Health and Safety Executive.
+In the UK nuclear context, it is a standard requirement for licensed sites that "The licensee shall make and implement adequate arrangements to ensure that only suitably qualified and experienced persons 
+perform any duties which may affect the safety of operations on the site or any other duties assigned by or under these conditions or any arrangements required under these conditions.".  
+
+In this context the term is not restricted to professionally qualified personnel or to duties requiring significant technical expertise: any means any It is essential that all personnel whose activities have the potential to impact on nuclear safety are suitably qualified and experienced (SQEP) to carry out their jobs.  This includes both those who directly carry out operations and others such as directors, managers, designers, safety case authors etc whose roles, if inadequately conceived or executed, may affect safety in less visible ways – for example, through introducing latent technical or organisational weaknesses. and conversely suitably means suitably, not particularly well: the Office of Nuclear Regulation takes SQEPness to be broadly equivalent to the International Atomic Energy Agency concept of 'competence' IAEA has defined competence as "the ability to put skills and knowledge into practice in order to perform a job in an effective and efficient manner to an established standard" ONR concurs with this definition, which is widely accepted within the international nuclear community.  Other factors contributing to a person's competence include the person's prior experience, aptitudes, attitudes, behaviours, skills and qualifications.
+In the context of UK nuclear licensing, the term "duly authorised person" (DAP) was extensively used for trained and experience operational staff, on plant or in control rooms.  This may have come from UK power-station practice originating with the CEGB and nuclear operations.
+SQEP was introduced for those staff who may not have direct responsibility on plant, but whose actions or input could be safety related.
+SQEP is also in wider usage in engineering, defence, human factors, training and safety-related contexts.
+In spoken usage, a person can describe themselves as SQEP'd, as in "I'm not SQEP'd for that."
+
+
+== References ==

data/en.wikipedia.org/wiki/Safety_Equipment_Institute-0.md

@@ -0,0 +1,24 @@
+---
+title: "Safety Equipment Institute"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Safety_Equipment_Institute"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:53:22.788432+00:00"
+instance: "kb-cron"
+---
+
+The Safety Equipment Institute (SEI) is a private, non-profit organization established to administer non-governmental, third-party certification programs to test and certify a broad range of safety and protective products.  As of April 2016, it became an affiliate of ASTM International, a global standards development organization.  It is accredited to ISO/IEC 17065, Conformity Assessment - Requirements for bodies certifying products, processes and services, by the ANSI National Accreditation Board (ANAB).  It works with assorted standards organizations to verify that various products meet the safety standards set for them.  Products certified by SEI may bear the SEI Certification Mark.
+
+
+== See also ==
+American National Standards Institute (ANSI)
+International Organization for Standardization (ISO)
+ASTM International
+
+
+== References ==
+
+
+== External links ==
+Safety Equipment Institute

data/en.wikipedia.org/wiki/Saturation_(traffic)-0.md

@@ -0,0 +1,30 @@
+---
+title: "Saturation (traffic)"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Saturation_(traffic)"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:53:23.934139+00:00"
+instance: "kb-cron"
+---
+
+In traffic engineering, saturation describes the maximum traffic flow which can be handled by a junction. The saturation flow is the rate at which a continuous flow of vehicles can pass through a constant green signal, typically expressed in vehicles per hour or PCUs per hour. 
+A formula to calculate saturation flows based on lane geometry is given in Transport and Road Research Laboratory RR67. However, the formula can over-estimate saturation flows at congested locations.
+
+
+== Degree of Saturation ==
+The degree of saturation (DoS) of an intersection (typically under traffic signal control) or a link measures the demand relative to the total capacity. A DoS value of 100% meaning that demand and capacity are equal and no further traffic is able to progress through the junction. The formula to calculate DoS is:
+
+Degree of saturation = (demand x cycle time) / (saturation flow x effective green time)
+Values over 85%-90% typically indicate traffic congestion, with queues of vehicles beginning to form. The  practical reserve capacity (PRC) refers to the available spare capacity at a junction.
+
+
+== Ratio of Flow to Capacity ==
+For priority junctions including roundabouts, the equivalent measure to DoS is the ratio of flow to capacity (RFC).
+
+
+== References ==
+
+
+== External links ==
+Transport for London - Modelling Guidelines

data/en.wikipedia.org/wiki/School_of_Engineering_of_Juiz_de_Fora-0.md

@@ -0,0 +1,21 @@
+---
+title: "School of Engineering of Juiz de Fora"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/School_of_Engineering_of_Juiz_de_Fora"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:53:25.102647+00:00"
+instance: "kb-cron"
+---
+
+The School of Engineering of Juiz de Fora (Portuguese: Escola de Engenharia de Juiz de Fora) was an engineering college in Juiz de Fora, Brazil. Since 1960, it has formed the Faculty of Engineering the Federal University of Juiz de Fora (UFJF). Brazil’s former president, Itamar Franco, was an alumnus. 
+
+It was established in 1914 in Juiz de Fora, Minas Gerais, and offered a five-year program in civil and electrotechnic engineering. In 1960, the school merged with the city’s schools of Medicine, Pharmacy, and Law to form the Federal University of Juiz de Fora (UFJF).
+The Faculty of Engineering offers programs in civil, production, electrical (telecommunications; energy and power systems; electronics; robotics and automation), mechanical, computer, sanitary and environmental engineering, as well as architecture.
+
+
+== References ==
+
+
+== External links ==
+UFJF web site

data/en.wikipedia.org/wiki/Self-discharger-0.md

@@ -0,0 +1,20 @@
+---
+title: "Self-discharger"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Self-discharger"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:53:27.481342+00:00"
+instance: "kb-cron"
+---
+
+A self-discharger (or self-unloader) is a ship that is able to discharge its cargo using its own gear. The most common discharge method for bulk cargo is to use an excavator that is fitted on a traverse running over the vessel's entire hatch, and that is able to move sideways as well. Lake freighters on the Great Lakes use conveyor-based unloading gear to empty funnel-shaped holds from the bottom, lifting the bulk cargo onto a boom. 
+
+
+== See also ==
+Adam E. Cornelius
+Auxiliary crane ship
+Boland and Cornelius Company
+
+
+== References ==

data/en.wikipedia.org/wiki/Sending_loudness_rating-0.md

@@ -0,0 +1,17 @@
+---
+title: "Sending loudness rating"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Sending_loudness_rating"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:53:28.664698+00:00"
+instance: "kb-cron"
+---
+
+The sending loudness rating (SLR) is a measure of the loudness of the transmit audio sent through the microphone of a communication device (for example, a mobile phone) It compares the Sound intensity of the sound waves into the microphone to the resulting audio signal. It is measured in dBV/Pa.
+For telephony, the reference sound pressure level is 20 micro-Pascals, with values in dB referenced to that value. 
+20 micro-Pascals is called the Threshold of human hearing, and is equal to 0 dB Sound pressure level (SPL).
+ITU-T recommendation P.79 has the frequency weighted sensitivity calculations in it for sending loudness rating (SLR) and receive loudness rating (RLR) for telephony.
+
+
+== References ==

data/en.wikipedia.org/wiki/Serviceability_failure-0.md

@@ -0,0 +1,15 @@
+---
+title: "Serviceability failure"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Serviceability_failure"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:53:29.840165+00:00"
+instance: "kb-cron"
+---
+
+In engineering, a serviceability failure occurs when a structure does not collapse, but rather fails to meet the required specifications. For example, severe wind may cause an excess of vibration at a pedestrian bridge making it impossible to cross it safely or comfortably. Similar excessive vibrations can be caused by pedestrians due to their walking, running, or jumping. Similarly, storm conditions may cause water to spill over a coastal structure, so that boats are not safe behind the structure.
+Examples of serviceability failures include deformations, vibration, cracking, and leakages.
+
+
+== References ==

data/en.wikipedia.org/wiki/Shelf_support-0.md

@@ -0,0 +1,21 @@
+---
+title: "Shelf support"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Shelf_support"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:53:31.002350+00:00"
+instance: "kb-cron"
+---
+
+A shelf support is a fastener used to hang a shelf from a wall. It can be an alternative to built-in shelving or adjustable shelving.
+There are several different types of shelf supports. A very common variant is an L-shaped shelf support, which is also called shelf bracket, and can be seen as a subset of angle brackets. There are also other forms of plug-in shelf supports commonly used in a wardrobes or cabinets (cabinet shelf support, wardrobe shelf support, shelf pin, shelf support peg, shelf support push).
+
+
+== See also ==
+Bracket (architecture)
+French cleats
+The 32 mm system on frameless cabinets using 5 mm diameter studs spaced 32 mm apart
+
+
+== References ==

data/en.wikipedia.org/wiki/Shift-invariant_system-0.md

@@ -0,0 +1,78 @@
+---
+title: "Shift-invariant system"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Shift-invariant_system"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:53:32.164944+00:00"
+instance: "kb-cron"
+---
+
+In signal processing, a shift invariant system is the discrete equivalent of a time-invariant system, defined such that if 
+  
+    
+      
+        y
+        (
+        n
+        )
+      
+    
+    {\displaystyle y(n)}
+  
+ is the response of the system to 
+  
+    
+      
+        x
+        (
+        n
+        )
+      
+    
+    {\displaystyle x(n)}
+  
+, then 
+  
+    
+      
+        y
+        (
+        n
+        −
+        k
+        )
+      
+    
+    {\displaystyle y(n-k)}
+  
+ is the response of the system to 
+  
+    
+      
+        x
+        (
+        n
+        −
+        k
+        )
+      
+    
+    {\displaystyle x(n-k)}
+  
+. That is, in a shift-invariant system, the contemporaneous  response of the output variable to a given value of the input variable does not depend on when the input occurs; time shifts are irrelevant in this regard.
+
+
+== Applications ==
+Because digital systems need not be causal, some operations can be implemented in the digital domain that cannot be implemented using discrete analog components. Digital filters that require finite numbers of future values can be implemented while the analog counterparts cannot.
+
+
+== Notes ==
+
+
+== References ==
+Oppenheim, Schafer, Digital Signal Processing, Prentice Hall, 1975, ISBN 0-13-214635-5
+
+
+== See also ==
+LTI system theory

data/en.wikipedia.org/wiki/Shunt_generator-0.md

@@ -0,0 +1,36 @@
+---
+title: "Shunt generator"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Shunt_generator"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:53:33.559711+00:00"
+instance: "kb-cron"
+---
+
+A shunt generator is a type of electric generator in which field winding and armature winding are connected in parallel, and in which the armature supplies both the load current and the field current for the excitation (generator is therefore self excited).
+
+
+== Generator field connections ==
+A shunt field (and any series resistor used for adjustment) may be directly connected across the armature terminals in parallel with the load. Where the machine has a series compounding winding, the field may be connected at the armature side (short shunt) or load side (long shunt).  The different connections give different voltage regulation characteristics on load. So as it is connected in shunt it has constant characteristics.
+
+
+== Characteristic ==
+Current in the field windings of a shunt-wound generator is (approximately) independent of the load current, because currents in parallel branches are independent of each other. Since field current, and therefore field strength, is little affected by load current, the output voltage remains more nearly constant than does the output voltage of a series-wound generator. 
+There will be a small armature voltage drop on the load, which will be reflected in the voltage applied to the shunt field. The output voltage in a DC shunt-wound generator drops slightly as load current increases because of the voltage drop across the armature resistance.
+
+
+== Usage ==
+Self-energizing shunt generators were widely used on automobiles after the decline in usage of third-brush generators c. 1940 but before the proliferation of alternators in the 1960's. Shunt generators are always used with regulators that regulate overvoltage and overcurrent, and disconnect the generator at undervoltage.
+
+
+== Compound winding ==
+In a shunt-wound generator, output voltage varies inversely with load current. In a series-wound generator, output voltage varies directly with load current. A combination of the two types can overcome the disadvantages of both. This combination of windings is called a compound-wound dc generator.
+
+
+== See also ==
+DC motor
+Excitation (magnetic)
+
+
+== References ==

data/en.wikipedia.org/wiki/Signal-to-noise_ratio_(imaging)-0.md

@@ -0,0 +1,111 @@
+---
+title: "Signal-to-noise ratio (imaging)"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Signal-to-noise_ratio_(imaging)"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:53:36.013980+00:00"
+instance: "kb-cron"
+---
+
+Signal-to-noise ratio (SNR) is used in imaging to characterize image quality.  The sensitivity of a (digital or film) imaging system is typically described in the terms of the signal level that yields a threshold level of SNR.
+Industry standards define sensitivity in terms of the ISO film speed equivalent, using SNR thresholds (at average scene luminance) of 40:1 for "excellent" image quality and 10:1 for "acceptable" image quality.
+SNR is sometimes quantified in decibels (dB) of signal power relative to noise power, though in the imaging field the concept of "power" is sometimes taken to be the power of a voltage signal proportional to optical power; so a 20 dB SNR may mean either 10:1 or 100:1 optical power, depending on which definition is in use.
+
+
+== Definition of SNR ==
+Traditionally, SNR is defined to be the ratio of the average signal value 
+  
+    
+      
+        
+          μ
+          
+            
+              s
+              i
+              g
+            
+          
+        
+      
+    
+    {\displaystyle \mu _{\mathrm {sig} }}
+  
+ to the standard deviation  of the signal 
+  
+    
+      
+        
+          σ
+          
+            
+              s
+              i
+              g
+            
+          
+        
+      
+    
+    {\displaystyle \sigma _{\mathrm {sig} }}
+  
+:
+
+  
+    
+      
+        
+          S
+          N
+          R
+        
+        =
+        
+          
+            
+              μ
+              
+                
+                  s
+                  i
+                  g
+                
+              
+            
+            
+              σ
+              
+                
+                  s
+                  i
+                  g
+                
+              
+            
+          
+        
+      
+    
+    {\displaystyle \mathrm {SNR} ={\frac {\mu _{\mathrm {sig} }}{\sigma _{\mathrm {sig} }}}}
+  
+
+when the signal is an optical intensity, or as the square of this value if the signal and noise are viewed as amplitudes (field quantities).
+
+
+== See also ==
+Coefficient of variation
+Contrast-to-noise ratio
+Minimum resolvable contrast
+Minimum resolvable temperature difference
+Optical transfer function
+Signal-to-noise ratio
+Signal transfer function
+
+
+== References ==
+
+
+== Further reading ==
+ISO 15739:2003, Photography – Electronic still-picture imaging – Noise measurements: specifies methods for measuring and reporting the noise versus signal level and dynamic range of electronic still-picture cameras. It applies to both monochrome and colour electronic still-picture cameras.
+ISO 12232:2006, Photography – Digital still cameras – Determination of exposure index, ISO speed ratings, standard output sensitivity, and recommended exposure index: specifies the method for assigning and reporting ISO speed ratings, ISO speed latitude ratings, standard output sensitivity values, and recommended exposure index values for digital still cameras. ISO 12232:2006 is applicable to both monochrome and colour digital still cameras. It revises ISO 12232:1998.

data/en.wikipedia.org/wiki/Signal_overspill-0.md

@@ -0,0 +1,23 @@
+---
+title: "Signal overspill"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Signal_overspill"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:53:34.785359+00:00"
+instance: "kb-cron"
+---
+
+Signal overspill is the receiving of a broadcast signal outside of its geographical target area. Radio frequencies have no way of obeying geographical borders and licensing arrangements, and the extent of overspill depends on where broadcast transmitters are sited and their power. In addition to traditional transmitters, overspill occurs when the footprint of a satellite is greater than that needed to serve its target audience.
+Transmitters located near to international borders may overspill into a large part of a neighbouring country, for example the signal from Republic of Ireland broadcaster 2RN's Clermont Carn site can be picked up in a large swathe of Northern Ireland, and vice versa BBC broadcasts can be picked up in the Republic. Another example is signal overspill within the Indonesia–Malaysia–Singapore growth triangle.
+Overspill is usually welcomed by listeners and viewers as it gives them additional choices. For example, when the Republic of Ireland began to migrate its television broadcasts to a digital platform, measures were put in place so that viewers in Northern Ireland could continue to receive the channels they had become used to. However, legally and often politically overspill can be  unwelcome. Broadcast rights are sold on a per territory basis, and overspill can be seen as harmful to  the commercial and intellectual property rights of creators. 
+Politically some governments may be wary of their own populace becoming too familiar with the culture of a neighbouring country or territory and feel threatened by it. For example, in China prior to its reforms, television dramas from Hong Kong could be easily picked up in neighbouring Guangdong, and helped spread the desire for greater liberty and material goods in Guangdong. Cross border radio and television reception was an important influence on political developments in Germany during the Cold War.  North Korea, on the other hand, completely outlaws reception of signals from outside the country.
+Overspill may have an accidental soft power effect, for example for many years listeners in the Netherlands were able to pick up BBC radio signals, listeners wanting to learn English would tune into the BBC leading to a British cultural influence on the Netherlands. Some nations will purposefully site transmitters and broadcast at a higher power than strictly necessary as a purposeful exercise in soft power. With regards to television, countries wishing to prevent this will choose a television encoding system incompatible to that of its neighbours.
+Overspill is used as a cover by stations, such as those known as border blaster and those of the radio périphérique, where the audience supposedly accidentally receiving a broadcast is actually the intended audience. The transmitters used are positioned and are very much more powerful than that needed to serve their licensed audience.
+
+
+== See also ==
+Rimshot (broadcasting)
+
+
+== References ==

data/en.wikipedia.org/wiki/Signal_tone-0.md

@@ -0,0 +1,23 @@
+---
+title: "Signal tone"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Signal_tone"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:53:37.284385+00:00"
+instance: "kb-cron"
+---
+
+A signal tone or signalling tone is a steady or pulsating periodic signal typically in the frequency range of sound for indicating a condition, communication protocol state, or serve as an audible warning.  It may be composed of multiple frequency components, or could be a pure tone.
+In telephone systems, signaling tones are used as call progress tones for in-band indications to subscribers or operators. Certain telephone switching systems used tones, in-band or out-of-band, for signaling on trunks.
+Typical well-known call progress tones are dial tone, ringing tone, busy tone, and the reorder tone. A loud stutter tone is used to alert subscribers of a handset left off-hook, effectively disabling the circuit for receiving calls.
+Telephone service subscribers may subscribe to services, such as call forwarding, which may indicate function by a stutter dial tone.
+
+
+== See also ==
+Musical tone
+Dual-tone multi-frequency signaling (DTMF)
+Signaling (telecommunications)
+
+
+== References ==

data/en.wikipedia.org/wiki/Silicone_impregnated_refractory_ceramic_ablator-0.md

@@ -0,0 +1,24 @@
+---
+title: "Silicone impregnated refractory ceramic ablator"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Silicone_impregnated_refractory_ceramic_ablator"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:53:38.485243+00:00"
+instance: "kb-cron"
+---
+
+Silicone Impregnated Refractory Ceramic Ablator, or SIRCA, is a lightweight ceramic ablative material, often used in thermal protection systems to protect parts of launch vehicles and spacecraft from very high temperature heat sources.
+SIRCA was used for ceramic substrates on both the Viking spacecraft and the Space Shuttle, and was also used on the aeroshells for Mars Pathfinder and the Mars Exploration Rovers.  It was developed at NASA Ames Research Center in the 1980s and 1990s.
+
+
+== Types ==
+According to NASA's TPSX database, there are three types of SIRCA in use: SIRCA-25L, SIRCA-15F and SIRCA-14A, each based on a different ceramic insulation substrate. Each type of SIRCA has a different acceptable heating rate, maximum heating load and mechanical strength.
+
+
+== Description ==
+SIRCA typically has a density between 0.20–0.40 grams per cubic centimetre (12–25 lb/cu ft) and can handle a heat flux of up to 300 watts per square centimetre (2.6 hp/sq in)
+and is easily machined to custom shapes.
+
+
+== References ==

data/en.wikipedia.org/wiki/Single-input_single-output_system-0.md

@@ -0,0 +1,24 @@
+---
+title: "Single-input single-output system"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Single-input_single-output_system"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:53:39.682898+00:00"
+instance: "kb-cron"
+---
+
+In control engineering, a single-input and single-output (SISO) system is a simple single-variable control system with one input and one output. In radio, it is the use of only one antenna both in the transmitter and receiver.
+
+
+== Details ==
+SISO systems are typically less complex than multiple-input multiple-output (MIMO) systems. Usually, it is also easier to make an order of magnitude or trending predictions "on the fly" or "back of the envelope". MIMO systems have too many interactions for most of us to trace through them quickly, thoroughly, and effectively in our heads.
+Frequency domain techniques for analysis and controller design dominate SISO control system theory. Bode plot, Nyquist stability criterion, Nichols plot, and root locus are the usual tools for SISO system analysis. Controllers can be designed through the polynomial design, root locus design methods to name just two of the more popular. Often SISO controllers will be PI, PID, or lead-lag.
+
+
+== See also ==
+Control theory
+
+
+== References ==
+Partington, Jonathan R. (2004). Linear Operators and Linear Systems: An Analytical Approach to Control Theory. Cambridge University Press. p. 75. ISBN 0-521-54619-2.

data/en.wikipedia.org/wiki/Small_Missions_for_Advanced_Research_in_Technology-0.md

@@ -0,0 +1,20 @@
+---
+title: "Small Missions for Advanced Research in Technology"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Small_Missions_for_Advanced_Research_in_Technology"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:53:40.901807+00:00"
+instance: "kb-cron"
+---
+
+Small Missions for Advanced Research in Technology (SMART) was a European Space Agency programme for building technology demonstrator space probes and testing them in outer space as space missions.
+SMART missions include:
+
+SMART-1, a mission to test electric propulsion rockets, by using Hall-effect thrusters; and also used as an outer space probe, and lunar probe.
+SMART-2 LISA Pathfinder, a mission to test the feasibility of formation flying multiple satellites for precision laser measurement, for use as a gravity wave detector.
+SMART-3, an unfulfilled 2006 design deadline.
+SMART-4, an unfulfilled 2009 design deadline.
+
+
+== References ==

data/en.wikipedia.org/wiki/Space_Data_Integrator-0.md

@@ -0,0 +1,24 @@
+---
+title: "Space Data Integrator"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Space_Data_Integrator"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:53:42.087139+00:00"
+instance: "kb-cron"
+---
+
+Space Data Integrator is a process/service platform or tool being developed by the US FAA to integrate space launch and reentry into the US National Airspace System. It intends to oversee and manage airspace safety during space operations, ensuring the safety of vehicles more efficiently than manual processes.
+
+
+== History ==
+The project was initiated in 2015.
+No funds for SDI were included in the FAA 2018 budget request.
+In March 2018 the FAA initiated a Market Survey on the requirements for SDI.
+
+
+== References ==
+
+
+== Further reading ==
+Improving the Integration of Launch and Reentry Operations into the National Airspace System Mazzotta and Murray. 2015?

data/en.wikipedia.org/wiki/Space_fountain-0.md

@@ -0,0 +1,29 @@
+---
+title: "Space fountain"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Space_fountain"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:53:43.328659+00:00"
+instance: "kb-cron"
+---
+
+A space fountain is a proposed form of an extremely tall tower extending into space. As known materials cannot support a static tower with this height, a space fountain has to be an active structure: A stream of pellets is accelerated upwards from a ground station. At the top it is deflected downwards. The necessary force for this deflection supports the station at the top and payloads going up the structure. A spacecraft could launch from the top without having to deal with the atmosphere. This could reduce the cost of placing payloads into orbit. Its largest downside is that the tower will re-enter the atmosphere if the accelerator fails and the stream stops. This risk could be reduced by several redundant streams.
+The lower part of a pellet stream has to be in a vacuum tube to avoid excessive drag in the atmosphere. Similar to the top station, this tube can be supported by its own system of transferring momentum from a space-bound stream to a surface-bound stream. If the tube itself also accelerates the station-supporting stream, it would have to transfer additional momentum to an earth-bound stream in order to keep itself supported. The tube-supporting streams could also be designed to integrate with the station-supporting streams.
+Unlike a space elevator, this concept does not need extremely strong materials anywhere, and unlike space elevators and orbital rings, it does not need a 40,000-kilometre (25,000 mi) long structure.
+
+
+== See also ==
+Launch loop
+Mass driver
+Megascale engineering
+Non-rocket spacelaunch
+Orbital ring
+Space elevator
+Space gun
+
+
+== References ==
+
+
+== Further reading ==

data/en.wikipedia.org/wiki/Span_(engineering)-0.md

@@ -0,0 +1,197 @@
+---
+title: "Span (engineering)"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Span_(engineering)"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:53:44.570217+00:00"
+instance: "kb-cron"
+---
+
+In engineering, span is the distance between two adjacent structural supports (e.g., two piers) of a structural member (e.g., a beam). Span is measured in the horizontal direction either between the faces of the supports (clear span) or between the centers of the bearing surfaces (effective span). For a bridge, the total span is the distance between the faces of the abutments:
+
+A span can be closed by a solid beam or by a rope. The first kind is used for bridges, the second one for power lines, overhead telecommunication lines, some type of antennas or for aerial tramways.
+
+Span is a significant factor in finding the strength and size of a beam as it determines the maximum bending moment and deflection. The maximum bending moment 
+  
+    
+      
+        
+          M
+          
+            m
+            a
+            x
+          
+        
+      
+    
+    {\displaystyle M_{max}}
+  
+ and deflection 
+  
+    
+      
+        
+          δ
+          
+            m
+            a
+            x
+          
+        
+      
+    
+    {\displaystyle \delta _{max}}
+  
+in the pictured beam is found using:
+
+  
+    
+      
+        
+          M
+          
+            m
+            a
+            x
+          
+        
+        =
+        
+          
+            
+              q
+              
+                L
+                
+                  2
+                
+              
+            
+            8
+          
+        
+      
+    
+    {\displaystyle M_{max}={\frac {qL^{2}}{8}}}
+  
+
+  
+    
+      
+        
+          δ
+          
+            m
+            a
+            x
+          
+        
+        =
+        
+          
+            
+              5
+              
+                M
+                
+                  m
+                  a
+                  x
+                
+              
+              
+                L
+                
+                  2
+                
+              
+            
+            
+              48
+              E
+              I
+            
+          
+        
+        =
+        
+          
+            
+              5
+              q
+              
+                L
+                
+                  4
+                
+              
+            
+            
+              384
+              E
+              I
+            
+          
+        
+      
+    
+    {\displaystyle \delta _{max}={\frac {5M_{max}L^{2}}{48EI}}={\frac {5qL^{4}}{384EI}}}
+  
+
+where 
+
+  
+    
+      
+        q
+      
+    
+    {\displaystyle q}
+  
+ = Uniformly distributed load
+
+  
+    
+      
+        L
+      
+    
+    {\displaystyle L}
+  
+ = Length of the beam between two supports (span)
+
+  
+    
+      
+        E
+      
+    
+    {\displaystyle E}
+  
+ = Modulus of elasticity
+
+  
+    
+      
+        I
+      
+    
+    {\displaystyle I}
+  
+ = Area moment of inertia
+The maximum bending moment and deflection occur midway between the two supports. From this it follows that if the span is doubled, the maximum moment (and with it the stress) will quadruple, and deflection will increase by a factor of sixteen.
+
+
+== See also ==
+List of spans — longest spans of ropes used as power lines, antennas or aerial tramways.
+List of longest suspension bridge spans
+List of longest cantilever bridge spans
+
+
+== References ==
+
+
+== Sources ==
+Brett, P. (2012). Illustrated Dictionary of Building. CRC Press. ISBN 978-1-135-13857-8. Retrieved 2023-12-16.

data/en.wikipedia.org/wiki/Splash_zone-0.md

@@ -0,0 +1,13 @@
+---
+title: "Splash zone"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Splash_zone"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:53:46.979191+00:00"
+instance: "kb-cron"
+---
+
+In offshore construction, the splash zone is the transition from air to water when lowering heavy burdens into the sea. The overall efforts applied on the crane change dramatically when the load starts touching water, up to the point where it is completely submerged. Its buoyancy reduces the static mass that the crane has to support, but contact with the waves creates widely fluctuating dynamic forces.
+Simulation of these changing efforts are necessary to correctly dimension cranes and lifting equipment. See for example DNV-RP-H103 (Det Norske Veritas recommended practices) for a mention of the piston effect created in the splash zone between two walls.
+Special made Access Tools are often made for doing inspections or maintenance in the splash zone, typical down to 15 m depth. This zone is very difficult to access for divers or remotely operated vehicles (ROV's) due to waves and current. Rigging of equipment in this zone also needs special precautions due to the same. By using Remotely Operated Equipment (Robots) that holds on to the structures, work and inspections can be done. Earlier this Zone was looked at as unaccessible.

data/en.wikipedia.org/wiki/Springhead_Pumping_Station-0.md

@@ -0,0 +1,14 @@
+---
+title: "Springhead Pumping Station"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Springhead_Pumping_Station"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:53:48.187983+00:00"
+instance: "kb-cron"
+---
+
+Springhead Pumping Station was a pumping station in Hull in England. It later became a waterworks museum.
+
+
+== References ==

data/en.wikipedia.org/wiki/Squeeze_job-0.md

@@ -0,0 +1,32 @@
+---
+title: "Squeeze job"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Squeeze_job"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:53:50.588593+00:00"
+instance: "kb-cron"
+---
+
+Squeeze job (or squeeze cementing) is a oilfield process of injecting cement slurry into a zone, generally for pressure-isolation purposes.
+
+
+== Description ==
+Squeeze job or squeeze cementing are terms often used in the oilfield to describe the process of injecting cement slurry into a zone, generally for pressure-isolation purposes.
+Usually the zone to be squeezed is isolated from above with a packer (and possibly from below with a bridge plug), but sometimes the squeezing pressure is applied to the entire casing string in what is known as a bradenhead squeeze (named for an old manufacturer of casing heads).
+
+
+== Etymology ==
+The term squeeze job probably originated from the concept that enough water is squeezed out of the slurry to render it unflowable, so the portion that has actually entered the zone will stay in place when the squeeze pressure is released.  After surface indications (e.g., pressure reaching a predetermined maximum) that a squeeze has been attained, any still-pumpable cement slurry remaining in the drill pipe or tubing ideally can be reverse circulated out before it sets.
+The generic term squeeze also can apply to injection of generally small volumes of other liquids (e.g., treating fluids) into a zone under pressure. Bullhead squeeze (or just plain bullheading) refers to pumping kill-weight mud down the casing beneath closed blowout preventers in a kick-control situation when it isn't feasible to circulate in such from bottom.
+
+
+== Background ==
+Even if a drilling rig is on location, pumping operations usually are done by a service company's cementing unit that can easily mix small batches of cement slurry, measure displacement volume accurately to spot the slurry on bottom, then pump at very low rates and high pressures during the squeeze itself, and finally measure volumes accurately again when reversing out any excess slurry.  A squeeze manifold is a compact arrangement of valves and pressure gauges that allows monitoring of the drill pipe and casing pressures throughout the job, and facilitates quick switching of the pumping pressure to either side while the fluid returning from the other side of well is directed to the mud pit or a disposal pit or tank.
+
+
+== See also ==
+Drilling rig (petroleum) — for a diagram of a drilling rig.
+
+
+== References ==

data/en.wikipedia.org/wiki/Squegging-0.md

@@ -0,0 +1,47 @@
+---
+title: "Squegging"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Squegging"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:53:51.789676+00:00"
+instance: "kb-cron"
+---
+
+Squegging is a radio engineering term. It is a contraction of self-quenching. A squegging or self-blocking oscillator produces an intermittent or changing output signal. Squegging is an oscillation that builds up and dies down with a much longer time constant than the fundamental frequency of the oscillation. For instance, in a radio system where the carrier frequency might be in the millions of cycles per second, squegging might occur at a frequency of hundreds or thousands of times a second.
+The effect was initially seen in early radio receivers, where it would cause the output to periodically drop to zero, or alternately, create a peak that would produce a periodic "pop" sound in the headphones or loudspeaker. In the later case, it was often known as "motorboating". It was generally caused by the use of an oscillator between the amplifier stages, which had some non-linear response which would cause the amplification to rise and fall over a time period much longer than the radio frequency signal. This could generally be corrected by changing some of the components to ones with slightly different values.
+The effect was later used deliberately to produce certain types of output. Armstrong's super-regenerative radio receiver is constructed such that the receiver sensitivity rises while the oscillation builds up and then stops when the operation point no longer fulfills the Barkhausen stability criterion. The oscillator recovers to the initial state and the cycle starts again, producing an output at a lower power. The result is that the steady input of radio signal turns into a series of shorter outputs at much lower frequency, producing an audible signal.
+The system was also used in some early radar systems to produce the short periodic pulses of electricity that powered the transmitters. Low-power versions of this same concept was used in metal detectors and wildlife tags for many years.
+
+
+== Unwanted squegging ==
+In order to produce a useful output signal from the tiny received radio signal, enough signal to drive headphones for instance, early radio receivers of the past generally used some form of feedback to amplify the signal. Among the most common techniques was the regenerative receiver, which fed the amplified output of a vacuum tube back into its input, which amplified the amplification. For short, steady tones, like Morse code, this led to tremendous amplification from a single tube, which at the time were very expensive.
+In order for this feedback system to be useful, the output had to be fed into an oscillator, often an LC tank. If the components in the oscillator were not carefully matched, it was possible that a non-linear effect would appear that would cause the amplification to grow so high as to overload the circuit when the signal strength increased, or alternately drop to zero when it decreased. This would cause the receiver to stop working until the signal in the oscillator naturally reset, which it would do at a rate normally defined by the capacitors in the circuit. It would then start working again, often only to have the process repeat, causing the receiver to drop out at regular intervals.
+Poor layout or poor shielding leads to high-frequency oscillations where the output has been coupled back to the input, especially if the input and output cables are run together for a distance.   The high-frequency oscillations cause heavy currents in the output stages and, with poor power supply decoupling, these upset the input stage biasing and disrupt the high frequency oscillations. Squegging then arises. A series resistor or a ferrite bead close to the gate or base connector of the active element reduces high frequency oscillations.
+As the art of receiver design improved, squegging became less common as designers had a better idea of the sorts of oscillator setups that would avoid this effect. Moreover, the introduction of the superheterodyne receiver and the emergence of voice transmissions on AM radio lessened its effect as these systems did not use as much feedback in any single stage, and later introductions of active control like automatic gain control generally eliminated it. Armstrong's own receiver used this effect as a control system.
+Squegging in audio amplifiers is commonly called motorboating because it sounds in the loudspeaker like an outboard boat motor at low speed.
+
+
+== Deliberate squegging ==
+The effect was well known from the 1920s through the 1950s, and became a way to deliberately produce periodic output. This was especially useful in early radar systems.
+Radar (normally) works by sending out short pulses of radio signal of very high power, which required power supplies that could generate such pulses of electricity, and tubes capable of working with such pulses. This was often expensive, requiring several triodes. For systems that required less power, like the smaller radars mounted in aircraft, deliberate squegging of the carrier frequency was used to generate these pulses from a much simpler circuit. In this case one sometimes sees the term "to squegg" describing this process.
+Later in the war the pulse width modulation concept was introduced, originally using cavity magnetrons, but later adapted to conventional very high frequency radios as well. These systems also generate short pulses of signal, and like radar, some of these were accomplished using squegging. It remained in use for low-cost transmitters in devices like metal detectors and animal trackers where a periodic output is needed at fairly low power levels.
+
+
+== Patents ==
+US 3782730, Horchler, Stephen A., "Golf Ball", published Dec. 2, 1971, issued Jan. 1, 1974 
+US 1424065, Armstrong, E. H., "Signalling system", published June 27, 1921, issued July 25, 1922 
+
+
+== See also ==
+AI Mk. IV radar
+
+
+== References ==
+
+
+=== Citations ===
+
+
+=== Sources ===
+Smith, R.A.; Hanbury-Brown, R.; Mould, A.J.; Ward, A.G.; Walker, B.A. (October 1985). "ASV: the detection of surface vessels by airborne radar". IEE Proceedings. 132 (6): 359–384.

data/en.wikipedia.org/wiki/Standard_work-0.md

@@ -0,0 +1,16 @@
+---
+title: "Standard work"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Standard_work"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:53:52.964729+00:00"
+instance: "kb-cron"
+---
+
+Standard work or standardized work is a lean manufacturing concept that aims for optimizing for best practices through the documentation of each work task, takt time, sequence of tasks, and resources to complete the task. The purpose is to create a consistent, efficient, and repeatable process that can be utilized by anyone enabling workers to reduce waste, improve quality, and increase productivity.
+Employees may be resistant to the deployment of standard work due resistance to change.
+Creating standardized work involves the development of a process capacity sheet, standardized work combination table, standardized work chart, and job instruction sheet.
+
+
+== References ==

data/en.wikipedia.org/wiki/Stovepipe_system-0.md

@@ -0,0 +1,25 @@
+---
+title: "Stovepipe system"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Stovepipe_system"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:53:54.165888+00:00"
+instance: "kb-cron"
+---
+
+In engineering and computing, "stovepipe system" is a pejorative term for a system that has the potential to share data or functionality with other systems but which does not do so. The term evokes the image of stovepipes rising above buildings, each functioning individually. A simple example of a stovepipe system is one that implements its own user IDs and passwords, instead of relying on a common user ID and password shared with other systems.
+Stovepipes are
+
+systems procured and developed to solve a specific problem, characterized by a limited focus and functionality, and containing data that cannot be easily shared with other systems.
+A stovepipe system is generally considered an example of an anti-pattern, particularly found in legacy systems. This is due to the lack of code reuse, and resulting software brittleness due to potentially general functions only being used on limited input.
+However, in certain cases stovepipe systems are considered appropriate, due to benefits from vertical integration and avoiding dependency hell. For example, the Microsoft Excel team has avoided dependencies and even maintained its own C compiler, which helped it to ship on time, have high-quality code, and generate small, cross-platform code.
+
+
+== See also ==
+Not invented here
+Reinventing the wheel
+Stovepipe (organisation)
+
+
+== References ==

data/en.wikipedia.org/wiki/Straight_line_engine_turning-0.md

@@ -0,0 +1,15 @@
+---
+title: "Straight line engine turning"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Straight_line_engine_turning"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:53:55.347161+00:00"
+instance: "kb-cron"
+---
+
+A straight line engine turning machine is a machine used for engraving decorative patterns on a surface. The engraving may be referred to as Guilloché, which also encompasses patterns created with the rose engine lathe. Where the rose engine is based on a lathe, the straight line engine has more in common with a metal planer machine.
+The straight line engine turning machine commonly consisted of an upright slide, a cross slide, a slide rest which holds the cutting tool, and a pattern bar holder
+
+
+== References ==

data/en.wikipedia.org/wiki/Strain_hardening_exponent-0.md

@@ -0,0 +1,87 @@
+---
+title: "Strain hardening exponent"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Strain_hardening_exponent"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:53:56.505314+00:00"
+instance: "kb-cron"
+---
+
+The strain hardening exponent (also called the strain hardening index), usually denoted 
+  
+    
+      
+        n
+      
+    
+    {\displaystyle n}
+  
+, is a measured parameter that quantifies the ability of a material to become stronger due to strain hardening. Strain hardening (work hardening) is the process by which a material's load-bearing capacity increases during plastic (permanent) strain, or deformation. This characteristic is what sets ductile materials apart from brittle materials. The uniaxial tension test is the primary experimental method used to directly measure a material's stress–strain behavior, providing valuable insights into its strain-hardening behavior.  
+The strain hardening exponent is sometimes regarded as a constant and occurs in forging and forming calculations, as well as the formula known as the Hollomon equation (after John Herbert Hollomon Jr.), originally posited as: 
+
+  
+    
+      
+        σ
+        =
+        K
+        
+          ϵ
+          
+            n
+          
+        
+      
+    
+    {\displaystyle \sigma =K\epsilon ^{n}}
+  
+
+where 
+  
+    
+      
+        σ
+      
+    
+    {\displaystyle \sigma }
+  
+ represents the applied true stress on the material, 
+  
+    
+      
+        ϵ
+      
+    
+    {\displaystyle \epsilon }
+  
+ is the true strain, and 
+  
+    
+      
+        K
+      
+    
+    {\displaystyle K}
+  
+ is the strength coefficient.
+The value of the strain hardening exponent lies between 0 and 1, with a value of 0 implying a perfectly plastic solid and a value of 1 representing a perfectly elastic solid. Most metals have an 
+  
+    
+      
+        n
+      
+    
+    {\displaystyle n}
+  
+-value between 0.10 and 0.50. In one study, strain hardening exponent values extracted from tensile data from 58 steel pipes from natural gas pipelines were found to range from 0.08 to 0.25, with the lower end of the range dominated by high-strength low alloy steels and the upper end of the range mostly normalized steels.
+
+
+== Tabulation ==
+
+
+== References ==
+
+
+== External links ==
+More complete picture about the strain hardening exponent in the stress–strain curve on www.key-to-steel.com

data/en.wikipedia.org/wiki/Structural_Engineering_exam-0.md

@@ -0,0 +1,14 @@
+---
+title: "Structural Engineering exam"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Structural_Engineering_exam"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:53:57.692116+00:00"
+instance: "kb-cron"
+---
+
+The Structural Engineering exam is a written examination given by state licensing boards in the United States as part of the testing for licensing structural engineers.  This exam is written by the National Council of Examiners for Engineering and Surveying. It consists of 4 separate exams covering vertical and lateral forces, which are split into "breadth" and "depth" exams. The "depth" exams are offered twice per year while the "breadth" exams are offered year round. All four exams are fully digital. 
+
+
+== References ==

data/en.wikipedia.org/wiki/Structural_testing-0.md

@@ -0,0 +1,21 @@
+---
+title: "Structural testing"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Structural_testing"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:53:58.899462+00:00"
+instance: "kb-cron"
+---
+
+Structural testing is the evaluation of an object (which might be an assembly of objects) to ascertain its characteristics of physical strength.  Testing includes evaluating compressive strength, shear strength, tensile strength, all of which may be conducted to failure or to some satisfactory margin of safety.  Evaluations may also be indirect, using techniques such as x-ray  ultrasound, and ground-penetrating radar, among others, to assess the quality of the object.
+Structural engineers conduct structural testing to evaluate material suitability for a particular application and to evaluate the capacity of existing structures to withstand foreseeable loads.
+Items may include buildings (or components), bridges, airplane wings or other types of structures.
+
+
+== See also ==
+Structural analysis
+Structural load
+
+
+== References ==

data/en.wikipedia.org/wiki/Structured_what-if_technique-0.md

@@ -0,0 +1,15 @@
+---
+title: "Structured what-if technique"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Structured_what-if_technique"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:54:00.111901+00:00"
+instance: "kb-cron"
+---
+
+The structured what-if technique (SWIFT) is a prospective hazards analysis method that uses structured brainstorming with guidewords and prompts to identify risks, with the aim of being quicker than more intensive methods like failure mode and effects analysis (FMEA). It is used in various settings, including healthcare.
+As with other methods, SWIFT may not be comprehensive and the approach has some limitations. In a healthcare context, SWIFT was found to reveal significant risks, but like similar methods (including healthcare failure mode and effects analysis) it may have limited validity when used in isolation.
+
+
+== References ==

data/en.wikipedia.org/wiki/Stub-girder_system-0.md

@@ -0,0 +1,53 @@
+---
+title: "Stub-girder system"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Stub-girder_system"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:54:01.293263+00:00"
+instance: "kb-cron"
+---
+
+A stub-girder system (or stub girder system) is a model of steel frame structures consisting of beams and decking, originally developed in the early 1970s in part by Joseph Colaco of Ellisor Engineers Inc.
+
+
+== Introduction ==
+Stub girder systems are a relatively common system in steel modern steel buildings, although they are rarely used anymore, they were very prevalent for a long span of time from the early 70s to the 80s. Though they are not really used anymore due to being uneconomical they are still very common and a lot of times when renovating the flooring in a tall steel building they will have to tear down stud girder systems.
+
+
+== Design and Components ==
+There are four main parts of a stub girder system, being the stubs, steel beams, concrete slab and the shear connectors.
+
+
+=== Stub ===
+This is the namesake of the stub girder system, and it is a short and thick metal beam that sits between the concrete slab and the metal beams. It is welded to the metal beams and connected to the concrete slab with shear connectors. This mostly helps create the strong connection between the steel beams that support the floor and the concrete slab which helps with shock resistance.
+
+
+=== Steel Beams ===
+There are two types of steel beams that are used in the stub girder system, there are the main steel beams that connect to the stubs, and they run parallel to the stubs. This is the beam that connects to the stub to help keep that structurally supported. There are also secondary beams that help to keep the concrete slab and floor from drooping and these beams sit on top of the main beams, which causes them to sit on the same level as the stubs but run perpendicular to the stubs. This also helps the floor have as few weak points as possible to keep the structure sound.
+
+
+=== Concrete Slab ===
+This is the part of the system that lies right on top of the stubs and the secondary steel beams. These are not always concrete with a lot of them being made from a composite that has a similar structure to that of concrete. Usually this will not be the final layer with possibly some metal on top of it or a more decorative material like tile or carpet on top of it to make the room more hospitable. These slabs also help to be a barrier between the steps and weight of the room and objects in the room from warping the metal beams over time because they can absorb some of the force and impact.
+
+
+=== Shear Connectors ===
+These are what connect the stub and secondary beams to the concrete slab because these connectors do not weaken the structure of the concrete slabs like bolts might. These are very important because if they are not used properly or connected properly then the floor might shift which could cause some serious problems in time.
+
+
+== Advantages and Disadvantages ==
+
+
+=== Advantages ===
+Stud girder systems are strong and structurally sound, with there being many beams to ensure that it does not collapse and different checks for structure like the use of both concrete and metal to give the structure a lot of load capacity but also helps to reduce impact with the concrete. The stud girder system also is light compared to alternate floor systems which allows the building to be a lot lighter compared to others that use different systems. One last advantage is that there is a lot of room for mechanical and electrical systems in the building like air conditioning or heating and things like electrical. This makes installing these systems much simpler and thus less expensive in the long run.
+
+
+=== Disadvantages ===
+Stud girder systems are expensive to use because of the amount of metal required to build them, especially if you are using steel for the beams and the girders. The stud girder systems are also complicated to set up which causes it to take much longer compared to other systems. This causes construction to cost more in the long term not even counting the expensive material cost.
+
+
+== Applications ==
+The main application for this system is in tall buildings with many stories or in buildings with large floors because the concrete slabs are cheap to install in large areas. The large load also allows the floor to carry a lot of different items or appliances.
+
+
+== References ==

data/en.wikipedia.org/wiki/Substrate_(building)-0.md

@@ -0,0 +1,22 @@
+---
+title: "Substrate (building)"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Substrate_(building)"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:54:02.492154+00:00"
+instance: "kb-cron"
+---
+
+The word substrate comes from the Latin  sub - stratum  meaning 'the level below' and refers to any material existing or extracted from beneath the topsoil, including sand, chalk and clay.
+ The term is also used for materials used in building foundations or else incorporated into plaster, brick, ceramic and concrete components, which are sometimes called 'filler' products.
+
+
+== See also ==
+Firestop
+Sealant
+Caulking
+Paint
+
+
+== References ==

data/en.wikipedia.org/wiki/Substructure_(engineering)-0.md

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+---
+title: "Substructure (engineering)"
+chunk: 1/1
+source: "https://en.wikipedia.org/wiki/Substructure_(engineering)"
+category: "reference"
+tags: "science, encyclopedia"
+date_saved: "2026-05-05T11:54:03.673997+00:00"
+instance: "kb-cron"
+---
+
+The substructure of a building transfers the load of the building, bridge, or other structure to the ground and isolates it horizontally from the ground. This includes foundations and basement retaining walls. It is differentiated from the superstructure.
+It safeguards the building against the forces of wind, uplift, soil pressure etc. It provides a level and firm surface for the construction of superstructure. It also prevents unequal or differential settlement and ensures stability of the building against sliding, overturning, undermine due to floodwater or burrowing animals.
+
+
+== References ==