Featured articles are displayed here, which represent some of the best content on English Wikipedia.
A Halkett boat is a type of lightweight inflatable boat designed by Lt Peter Halkett (1820–1885) during the 1840s. Halkett had long been interested in the difficulties of travelling in the Canadian Arctic, and the problems involved in designing boats light enough to be carried over arduous terrain, but robust enough to be used in extreme weather conditions.
Halkett's first design was a collapsible and inflatable boat made of rubber-impregnated cloth. When deflated, the hull of the boat could be worn as a cloak, the oar used as a walking stick, and the sail as an umbrella. This was followed by a two-man craft that was small enough to fit into a knapsack, and when deflated served as a waterproof blanket.
Although widely praised by Canadian explorers, Halkett's designs had a limited market, and he was unable to persuade the Royal Navy that they would serve any useful purpose in general naval service. Efforts to market them as platforms for fishing and duck shooting failed, and they were commercially unsuccessful. Only two Halkett boats, that of Orcadian explorer John Rae, and one held in the Hudson's Bay Company Museum Collection at the Manitoba Museum are known to survive today. (Full article...)
Grinding is an abrasive machining process that uses a grinding wheel as the cutting tool.
Grinding practice is a large and diverse area of manufacturing and toolmaking. It can produce very fine finishes and very accurate dimensions; yet in mass production contexts it can also rough out large volumes of metal quite rapidly. It is usually better suited to the machining of very hard materials than is "regular" machining (that is, cutting larger chips with cutting tools such as tool bits or milling cutters), and until recent decades it was the only practical way to machine such materials as hardened steels. Compared to "regular" machining, it is usually better suited to taking very shallow cuts, such as reducing a shaft’s diameter by half a thousandth of an inch or 12.7 μm.
These are Good articles, which meet a core set of high editorial standards.
Three Musketeers - Chrysler Engineers Carl Breer (right), Fred Zeder (center), and Owen Skelton (left) in 1933.
A voltage doubler is an electronic circuit which charges capacitors from the input voltage and switches these charges in such a way that, in the ideal case, exactly twice the voltage is produced at the output as at its input.
The simplest of these circuits are a form of rectifier which take an AC voltage as input and outputs a doubled DC voltage. The switching elements are simple diodes and they are driven to switch state merely by the alternating voltage of the input. DC-to-DC voltage doublers cannot switch in this way and require a driving circuit to control the switching. They frequently also require a switching element that can be controlled directly, such as a transistor, rather than relying on the voltage across the switch as in the simple AC-to-DC case. (Full article...)
She returned to Bristol in 1925, after being appointed a researcher in the Physics Department at the University of Bristol, with her salary being paid by the Department of Scientific and Industrial Research. In 1927, John Lennard-Jones was appointed Professor of Theoretical physics, a chair being created for him, with Dent becoming his research assistant in theoretical physics. Lennard‑Jones pioneered the theory of interatomic and intermolecular forces at Bristol and she became one of his first collaborators. They published six papers together from 1926 to 1928, dealing with the forces between atoms and ions, that were to become the foundation of her master's thesis. Later work has shown that the results they obtained had direct application to atomic force microscopy by predicting that non-contact imaging is possible only at small tip-sample separations. (Full article...)
The tubes were constructed using the shield method and are each 6,550 feet (2,000 m) long and 15.5 feet (4.7 m) wide. The interiors are lined with cast-iron "rings" formed with concrete. The tubes descend 91 to 95 feet (28 to 29 m) below the mean high water level of the East River, with a maximum gradient of 3.1 percent. During the tunnel's construction, a house at 58 Joralemon Street in Brooklyn was converted into a ventilation building and emergency exit. (Full article...)
In 1834, Charles Wheatstone developed a method of using a rapidly rotating mirror to study transient phenomena, and applied this method to measure the velocity of electricity in a wire and the duration of an electric spark. He communicated to François Arago the idea that his method could be adapted to a study of the speed of light. Arago expanded upon Wheatstone's concept in an 1838 publication, emphasizing the possibility that a test of the relative speed of light in air versus water could be used to distinguish between the particle and wave theories of light. (Full article...)
Raymix during a 2018 interview
Edmundo Gómez Moreno (born 17 February 1991), better known by his stage name Raymix, is a Mexican musician and aerospace engineer. Nicknamed El Rey de la Electrocumbia ("The King of Electrocumbia"), Raymix started his music career in the early 2010s, when he joined a trance project called Light & Wave with two other Mexican musicians. Their song "Feeling the City" was featured on the Armin van Buuren radio show A State of Trance. In 2013, Raymix was invited to work in a NASA educative internship, where he helped to develop a satellite.
HDMI implements the EIA/CEA-861 standards, which define video formats and waveforms, transport of compressed and uncompressed LPCM audio, auxiliary data, and implementations of the VESA EDID. CEA-861 signals carried by HDMI are electrically compatible with the CEA-861 signals used by the Digital Visual Interface (DVI). No signal conversion is necessary, nor is there a loss of video quality when a DVI-to-HDMI adapter is used. The Consumer Electronics Control (CEC) capability allows HDMI devices to control each other when necessary and allows the user to operate multiple devices with one handheld remote control device. (Full article...)
Joyner analyzing the operation of a wind tunnel turbine at NACA Langley in 1952
Schematic representation of the Dirac delta by a line surmounted by an arrow. The height of the arrow is usually meant to specify the value of any multiplicative constant, which will give the area under the function. The other convention is to write the area next to the arrowhead.
Genetic engineering, also called genetic modification or genetic manipulation, is the modification and manipulation of an organism's genes using technology. It is a set of technologies used to change the genetic makeup of cells, including the transfer of genes within and across species boundaries to produce improved or novel organisms. New DNA is obtained by either isolating and copying the genetic material of interest using recombinant DNA methods or by artificially synthesising the DNA. A construct is usually created and used to insert this DNA into the host organism. The first recombinant DNA molecule was made by Paul Berg in 1972 by combining DNA from the monkey virus SV40 with the lambda virus. As well as inserting genes, the process can be used to remove, or "knock out", genes. The new DNA can be inserted randomly, or targeted to a specific part of the genome.
An organism that is generated through genetic engineering is considered to be genetically modified (GM) and the resulting entity is a genetically modified organism (GMO). The first GMO was a bacterium generated by Herbert Boyer and Stanley Cohen in 1973. Rudolf Jaenisch created the first GM animal when he inserted foreign DNA into a mouse in 1974. The first company to focus on genetic engineering, Genentech, was founded in 1976 and started the production of human proteins. Genetically engineered human insulin was produced in 1978 and insulin-producing bacteria were commercialised in 1982. Genetically modified food has been sold since 1994, with the release of the Flavr Savr tomato. The Flavr Savr was engineered to have a longer shelf life, but most current GM crops are modified to increase resistance to insects and herbicides. GloFish, the first GMO designed as a pet, was sold in the United States in December 2003. In 2016 salmon modified with a growth hormone were sold. (Full article...)
Image 2Design of a turbine requires collaboration of engineers from many fields, as the system involves mechanical, electro-magnetic and chemical processes. The blades, rotor and stator as well as the steam cycle all need to be carefully designed and optimized. (from Engineering)
Image 3The application of the steam engine allowed coke to be substituted for charcoal in iron making, lowering the cost of iron, which provided engineers with a new material for building bridges. This bridge was made of cast iron, which was soon displaced by less brittle wrought iron as a structural material (from Engineering)
This list was generated from these rules. Questions and feedback are always welcome! The search is being run daily with the most recent ~14 days of results. Note: Some articles may not be relevant to this project.