omniomni/omni-engineering huggingface dataset:
Fleming's right-hand rule. In electromagnetism, Fleming's right-hand rule  (for generators) shows the direction of induced current when a conductor attached to a circuit moves in a magnetic field.  It can be used to determine the direction of current in a generator's windings.

When a conductor such as a wire attached to a circuit moves through a magnetic field, an electric current is induced in the wire due to Faraday's law of induction. The current in the wire can have two possible directions. Fleming's right-hand rule gives which direction the current flows.

The right hand is held with the thumb, index finger and middle finger mutually perpendicular to each other (at right angles), as shown in the diagram.

 The thumb is pointed in the direction of the motion of the conductor relative to the magnetic field.
 The first finger is pointed in the direction of the magnetic field. By convention, it's the direction from North to South magnetic pole.
 Then the second finger represents the direction of the induced or generated current within the conductor (from + to −, the terminal with lower electric potential to the terminal with higher electric potential, as in a voltage source)

The bolded letters in the directions above give a mnemonic way to remember the order. Another mnemonic for remembering the rule is the initialism "FBI", standing for Force (or otherwise motion), B the symbol for the magnetic field, and I the symbol for current. The subsequent letters correspond to subsequent fingers, counting from the top: thumb → F; first finger → B; second finger → I.

There is also a Fleming's left-hand rule (for electric motors). The appropriately handed rule can be recalled from the letter "g", which is in "right" and "generator".

These mnemonics are named after British engineer John Ambrose Fleming, who invented them.

An equivalent version of Fleming's right-hand rule is the left-hand palm rule.

Distinction between the right-hand and left-hand rule

See also
Right-hand rule
Fleming's left-hand rule for motors

References

External links
 Diagrams at magnet.fsu.edu
 Diagrams and exercises

Science mnemonics
Electromagnetism

zh:佛來明右手定則
Auster Agricola. The Auster B8 Agricola was a commercially unsuccessful British agricultural aircraft designed for the aerial topdressing market which opened up in New Zealand in the early 1950s.

Design
Constructed of fabric over a corrosion-proofed steel frame, the design featured a large high-lift low-set monoplane wing, external control cables, fixed tailwheel undercarriage and a somewhat angular fuselage. It had an aft cabin that could seat two passengers, a hopper over the centre of the wing which could hold 750 kg of superphosphate in the topdressing role, or 654 litres of spray as a crop duster. The pilot sat forward of the hopper over the wing leading edge, a position which gave a good field of view compared with the American practice of placing the pilot behind the hopper, though this view was somewhat restricted by the extensive canopy joinery and bulky rear decking. 

The Agricola's handling was generally described favourably, particularly its slow speed performance and controls, while its rugged and simple construction allowed for easy maintenance and repair.  The aircraft was utilitarian rather than attractive; one website has short-listed the Agricola in a competition for the ugliest aircraft of all time. The type was first flown in 1955.  

It was out-competed in its target market by the PAC Fletcher and attempts to sell the type for aerial application work in Britain, Australia and Europe met with little success.  Only nine were made before production ceased.  Of these ZK-BXO, is the sole survivor.  Restored by John Stephenson of Whitianga, it was operated for many years by him as both a historic aircraft and personal transport.  BXO was sold to the UK in 2005 and re-registered as G-CBOA. In March 2016, the aircraft was once again sold to New Zealand.

Specifications (Auster Agricola)

See also

References
Notes

Bibliography

External links

New Zealand forum discussion
G-INFO database entry for G-CBOA

Low-wing aircraft
Single-engined tractor aircraft
1950s British agricultural aircraft
Auster aircraft
Aircraft first flown in 1955
Aircraft with fixed conventional landing gear
Single-engined piston aircraft
Hoist controller. A hoist controller is the controller for a hoist.  The term is used primarily in the context of electrically operated hoists, but it is apparent that the control systems of many 20th century steam hoists also incorporated controllers of significant complexity.  Consider the control system of the Quincy Mine No. 2 Hoist. This control system included interlocks to close the throttle valve at the end of trip and to prevent opening the throttle again until the winding engine was reversed.  The control system also incorporated a governor to control the speed of the hoist and indicator wheels to show the hoist operator the positions of the skips in the mine shaft.

The hoist controllers for modern electric mining hoists have long included such features as automatic starting of the hoist when the weight of coal or ore in the skip reaches a set point, automatic acceleration of the hoist to full speed and automatic deceleration at the end of travel.
Hoist controllers need both velocity and absolute position references taken, typically taken from the winding drum of the hoist.  Modern hoist controllers replace many of the mechanical analog mechanisms of earlier controllers with digital control systems.

See also 
 Hydraulic hooklift hoist

References 

Mining equipment
Application domain. An application domain is a mechanism (similar to a process in an operating system) used within the Common Language Infrastructure (CLI) to isolate executed software applications from one another so that they do not affect each other. Each application domain has its own virtual address space which scopes the resources for the application domain using that address space.

Creating multiple application domains in the same process is not possible in .NET Core and .NET 5+.

Properties
A CLI application domain is contained within an operating system process. A process may contain many application domains. Application domains have isolation properties similar to that of operating system processes:
 Multiple threads can exist within a single application domain.
 An application within a domain can be stopped without affecting the state of another domain in the same process.
 A fault or exception in one domain does not affect an application in another domain or crash the entire process that hosts the domains.
 Configuration information is part of a domain's scope, not the scope of the process.
 Each domain can be assigned different security access levels.
 Code in one domain cannot directly access code in another.

In this sense, a CLI is like a mini-operating system. It runs a single process that contains a number of sub-processes, or application domains.

The advantage of application domains is that running multiple application domains may require fewer resources, such as memory, than running multiple operating system processes. Communication between domains still requires marshalling, so the overheads can be closer to using multiple processes than to communicating within a single domain.

Inter-domain communications
Direct communication cannot be achieved across application domains. However, application domains can still talk to each other by passing objects via marshalling by value (unbound objects), marshalling by reference through a proxy (application-domain-bound objects). There is a third type of object called a context-bound object which can be marshalled by reference across domains and also within the context of its own application domain. Because of the verifiable type-safety of managed code, a CLI can provide fault isolation between domains at a much lower cost than an operating system process can. The static type verification used for isolation does not require the same process switches or hardware ring transitions that an operating system process requires.

Managed code
Application domains are a purely managed code concept. Any included native/unmanaged code (e.g., C++) is largely unaware of them. Static variables seem to be shared across domains, callbacks can be problematic, and any memory corruption bugs in one domain is likely to corrupt other domains.

References

Microsoft Developer Network page on application domains
Unmanaged callbacks across AppDomains 

Software architecture
.NET terminology
Sodium selenite. Sodium selenite is the inorganic compound with the formula Na2SeO3. This salt is a colourless solid.  The pink coloured  pentahydrate Na2SeO3(H2O)5 is the most common water-soluble selenium compound.

Synthesis and fundamental reactions
Sodium selenite usually is prepared by the reaction of selenium dioxide with sodium hydroxide:
SeO2  +  2 NaOH   →   Na2SeO3  +  H2O

The hydrate converts to the anhydrous salt upon heating to 40 °C.

According to X-ray crystallography, both anhydrous Na2SeO3 and its pentahydrate feature pyramidal SeO32−.  The Se-O distances range from 1.67 to 1.72 Å. Oxidation of this anion gives sodium selenate, Na2SeO4.

Applications
Together with the related barium and zinc selenites, sodium selenite is mainly used in the manufacture of colorless glass. The pink color imparted by these selenites cancels out the green color imparted by iron impurities.

Because selenium is an essential element, sodium selenite is an ingredient in dietary supplements such as multi-vitamin/mineral products, but supplements that provide only selenium use L-selenomethionine or a selenium-enriched yeast.

The US Food and Drug Administration approved a selenium supplement to animal diets; the most common form is sodium selenite for pet foods. According to one article, "not much was known about which selenium compounds to approve for use in animal feeds when the decisions were made back in the 1970s .. At the time the regulatory action was taken, only the inorganic selenium salts (sodium selenite and sodium selenate) were available at a cost permitting their use in animal feed.”

Sodium selenite has been proposed as an effective suicide agent.

Safety
Selenium is toxic in high concentrations. As sodium selenite, the chronic toxic dose for human beings was described as about 2.4 to 3 milligrams of selenium per day. In 2000, the US Institute of Medicine set the adult Tolerable upper intake levels (UL) for selenium from all sources - food, drinking water and dietary supplements - at 400 μg/day. The European Food Safety Authority reviewed the same safety question and set its UL at 300 μg/day.

See also
Selenite (ion)
Selenous acid

References

External links
 Linus Pauling Institute page on selenium

Hazardous air pollutants
Selenites
Sodium compounds
Dietary minerals
Dietary supplements
Sodium tellurite. Sodium tellurite is an inorganic tellurium compound with formula Na2TeO3. It is a water-soluble white solid and a weak reducing agent. Sodium tellurite is an intermediate in the extraction of the element, tellurium; it is a product obtained from anode slimes and is a precursor to tellurium.

Preparation
The main source of tellurium is from copper anode slimes, which contain precious metals as well as various tellurides. These slimes are roasted with sodium carbonate and oxygen to produce sodium tellurite.

Ag2Te + Na2CO3 + O2 → 2Ag + Na2TeO3 + CO2 (400–500 °C)

This is a reaction with silver telluride. The telluride is oxidized to tellurite and the silver(I) is reduced to silver.

Purification
The electrolysis of a tellurite solution yields purified tellurium.

Anode: 4OH− → 2H2O + O2 + 4e−
Cathode: TeO32− + 3H2O + 4e− → Te + 6OH−

Structure and properties
Tellurium has properties similar to sulfur and selenium. In the anhydrous form Na2TeO3 the tellurium atoms are 6 coordinate, three Te-O at 1.87 Å and three at 2.9 Å, with distorted octahedra sharing edges. In the pentahydrate, Na2TeO3.5H2O there are discrete tellurite anions, TeO32− which are pyramidal. The Te-O distance is 1.85 - 1.86 Å and the O-Te-O angle is close to 99.5°. The tellurite anion is a weak base. Sodium tellurite would be similar to sodium selenite and sodium sulfite. Sodium tellurite is both a weak oxidizing agent and a weak reducing agent.

Tellurite-related reactions
H2TeO3 → H+ + HTeO3− pK 2.48

Telluric acid loses a proton at this pKa.

HTeO3− → H+ + TeO32− pK 7.7

Hydrogen tellurite loses a proton at this pKa to become the tellurite ion. This would happen in the reaction of tellurous acid with sodium hydroxide to make sodium tellurite.

TeO2 + 2OH− → TeO32− + H2O

This is the reaction of tellurium dioxide with a base to make a tellurite salt.

Applications
Sodium tellurite improves the corrosion resistance of electroplated nickel layers. Solutions of sodium tellurite are used for black or blue-black coatings on iron, steel, aluminum, and copper. In microbiology, sodium tellurite can be added to the growth medium to isolate bacteria with an inherent physiological resistance to its toxicity.

References

Cameo Chemicals. Sodium Tellurite. Retrieved March 8, 2009. Website: http://cameochemical.noaa.gov/chemical/5185.

Tellurites
Sodium compounds
Triethyl phosphate. Triethyl phosphate is an organic chemical compound with the formula (C2H5)3PO4 or OP(OEt)3.  It is a colorless liquid.  It is the triester of ethanol and phosphoric acid and can be called "phosphoric acid, triethyl ester".

Its primary uses are as an industrial catalyst (in acetic anhydride synthesis), a polymer resin modifier, and a plasticizer (e.g. for unsaturated polyesters). In smaller scale it is used as a solvent for e.g. cellulose acetate, flame retardant, an intermediate for pesticides and other chemicals, stabilizer for peroxides,  a strength agent for rubber and plastic including vinyl polymers and unsaturated polyesters, etc.

History
It was studied for the first time by French chemist Jean Louis Lassaigne in the early 19th century.

See also
Franz Anton Voegeli

References

Organophosphates
Plasticizers
Solvents
Ethyl esters
Phosphate esters
Flame retardants
CheetahTemplate. Cheetah (or CheetahTemplate) is a template engine that uses the Python programming language.  It can be used standalone or combined with other tools and frameworks.  It is often used for server-side scripting and dynamic web content by generating HTML, but can also be used to generate source code.  Cheetah is free open-source software licensed under the MIT License.

Templating engines encourage clean separation of content, graphic design, and program code. This leads to more modular, flexible, and reusable site architectures, shorter development time, and code that is easier to understand and maintain. Cheetah compiles templates into optimized, yet readable, Python code. It gives template authors full access to any Python data, and functionality, while providing a way for administrators to selectively restrict access to Python when needed.

Cheetah is included in the FreeBSD Ports collection and several Linux distributions: Gentoo, Fedora, Debian, and Ubuntu among others.

Example of Cheetah code 
#from Cheetah.Template import Template
#extends Template

#set $people = [{'name' : 'Tom', 'mood' : 'Happy'}, {'name' : 'Dick',
                        'mood' : 'Sad'}, {'name' : 'Harry', 'mood' : 'Hairy'}]

<strong>How are you feeling?</strong>
<ul>
    #for $person in $people
        <li>
            $person['name'] is $person['mood']
        </li>
    #end for
</ul>

References

External links 
 
 ONLamp.com tutorial 
 Dev Shed tutorial

Free system software
Free software programmed in Python
Python (programming language) software
Python (programming language) libraries
Scripting languages
Template engines
Potassium bisulfate. Potassium bisulfate (potassium bisulphate) is an inorganic compound with the chemical formula KHSO4 and is the potassium acid salt of sulfuric acid. It is a white, water-soluble solid.

Preparation
More than 1 million tons were produced in 1985 as the initial stage in the Mannheim process for producing potassium sulfate. The relevant conversion is the exothermic reaction of potassium chloride and sulfuric acid:

Potassium bisulfate is a by-product in the production of nitric acid from potassium nitrate and sulfuric acid:

Chemical properties
Thermal decomposition of potassium bisulfate forms potassium pyrosulfate:

Above 600 °C potassium pyrosulfate converts to potassium sulfate and sulfur trioxide:

Uses
Potassium bisulfate is commonly used to prepare potassium bitartrate for winemaking. Potassium bisulfate is also used as a disintegrating agent in analytical chemistry or as a precursor to prepare potassium persulfate, a powerful oxidizing agent.

Occurrence
Mercallite, the mineralogical form of potassium bisulfate, occurs very rarely. Misenite is another more complex form of potassium bisulfate with the formula K8H6(SO4)7.

References 

Sulfates
Potassium compounds
Acid salts
Uranium metallurgy. In materials science and materials engineering, uranium metallurgy is the study of the physical and chemical behavior of uranium and its alloys.

Commercial-grade uranium can be produced through the reduction of uranium halides with alkali or alkaline earth metals. Uranium metal can also be made through electrolysis of KUF5 or UF4, dissolved in a molten CaCl2 and NaCl. Very pure uranium can be produced through the thermal decomposition of uranium halides on a hot filament.

The uranium isotope 235U is used as the fuel for nuclear reactors and nuclear weapons.  It is the only isotope existing in nature to any appreciable extent that is fissile, that is, fissionable by thermal neutrons. The isotope 238U is also important because it absorbs neutrons to produce a radioactive isotope that subsequently decays to the isotope 239Pu (plutonium), which also is fissile.  Uranium in its natural state comprises just 0.71% 235U and 99.3% 238U, and the main focus of uranium metallurgy is the enrichment of uranium through isotope separation.

See also
Nuclear weapon design#Enriched materials
Uranium tile

References

Sources
Uranium
Enriched uranium
Nuclear weapon design
The technology of mining and metallurgy , retrieved 7 October 2005.

External links
The technology of mining and metallurgy
Building nuclear warheads: The process
List of Uranium Alloys

Uranium
Metallurgy
Fire hardening. Fire hardening is the process of removing moisture from wood, changing its structure and material properties, by charring it over or directly in a fire or a bed of coals. This has been thought to make a point, like that of a spear or arrow, or an edge, like that of a knife or axe, more durable and efficient for its use as a tool or weapon. An initial study suggests that the process might make the wood brittle but would substantially reduce the time needed to make a spear point.

Fire hardening may be done before, after, or during the manufacturing of the wooden tip. Longer procedures involving greasing and polishing with stones to impregnate the wood with fats and oils and silica may improve the effects of the process. Fire hardening was first developed by primitive humans at least 400,000 years ago, which was long before either flint or stone points were being made.

See also
 Wood working
 Flame polishing

References 

Timber preparation
Gripe (tool). A gripe is a simple form of clamp used in building a clinker boat, for temporarily holding the strake which is being fitted onto the one to which it is to be attached. The strake is relatively thin and wide, so the tool must have a long reach and requires only a small movement. This is achieved by taking two pieces of dense timber, typically oak, each of a length a little more than twice the widest width of the strake. A coach bolt is fitted through the middle and adjusted so that the gripe will fit onto the land (the joint between the adjacent strakes) while admitting the point of a wedge between the free ends of the two parts of the gripe. The wedge is then tapped in so that the gripe grips the land, using the bolt as a fulcrum.

Some definitions describe the gripe as being another name for the forefoot of a boat.

The name is pronounced with the "i" as a long diphthong and is a form of the word grip.

The word "gripe" has also been used to describe a pitchfork used to handle manure.

References 

Woodworking hand tools
Shipbuilding
Antonia Terzi. Antonia Terzi (29 April 1971 – 26 October 2021) was an Italian aerodynamicist who worked for the Ferrari and Williams Formula One teams.

Education
Terzi held a Master's degree in Materials Engineering from University of Modena and Reggio Emilia in Italy and a PhD in engineering, focused on aerodynamics, from University of Exeter in the United Kingdom.

Career

Born in Mirandola, Terzi worked in the design department at Ferrari under Rory Byrne until 2001 when she was recruited by Williams to become the team's chief aerodynamicist. 

The 2004 Williams FW26 featured a controversial 'Walrus nose' which did not work, it was replaced mid-season by a conventional design. Terzi left Williams in November 2004.

She was later employed as an assistant professor by The Delft University of Technology, working together with Professor Wubbo Ockels at the Faculty of Aerospace Engineering. She was the chief vehicle designer of the TU Delft Superbus.

From 2014 until 2019, she was the head of the aerodynamics team at Bentley Motors Ltd.

In 2020, she was appointed Full Professor at the Australian National University in Canberra, Australia.

Death
Terzi died in a car accident in the UK on 26 October 2021. The exact location and the details of the crash have not been disclosed.

References

1971 births
2021 deaths
Aerodynamicists
Academic staff of the Delft University of Technology
Formula One designers
Ferrari people
People from Mirandola
Women automotive engineers
Italian motorsport people
21st-century women engineers
Road incident deaths in England
Williams Grand Prix Engineering