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While there are numerous variations, stockless anchors consist of a set of heavy flukes connected by a pivot or ball and socket joint to a shank. Cast into the crown of the anchor is a set of tripping palms, projections that drag on the bottom, forcing the main flukes to dig in.
Small boat anchors
Until the mid-20th ... | Anchor | Wikipedia | 498 | 1358 | https://en.wikipedia.org/wiki/Anchor | Technology | Naval transport | null |
Many manufacturers produce a plough-type anchor, so-named after its resemblance to an agricultural plough. All such anchors are copied from the original CQR (Coastal Quick Release, or Clyde Quick Release, later rebranded as 'secure' by Lewmar), a 1933 design patented in the UK by mathematician Geoffrey Ingram Taylor.
... | Anchor | Wikipedia | 457 | 1358 | https://en.wikipedia.org/wiki/Anchor | Technology | Naval transport | null |
American Richard Danforth invented the Danforth Anchor in the 1940s for use aboard landing craft. It uses a stock at the crown to which two large flat triangular flukes are attached. The stock is hinged so the flukes can orient toward the bottom (and on some designs may be adjusted for an optimal angle depending on the... | Anchor | Wikipedia | 488 | 1358 | https://en.wikipedia.org/wiki/Anchor | Technology | Naval transport | null |
Bruce anchors can have difficulty penetrating weedy bottoms and grass. They offer a fairly low holding-power-to-weight ratio and generally have to be oversized to compete with newer types.
Scoop type anchors
Three time circumnavigator German Rolf Kaczirek invented the Bügel Anker in the 1980s. Kaczirek wanted an anch... | Anchor | Wikipedia | 442 | 1358 | https://en.wikipedia.org/wiki/Anchor | Technology | Naval transport | null |
Mantus: This is claimed to be a fast setting anchor with high holding power. It is designed as an all round anchor capable of setting even in challenging bottoms such as hard sand/clay bottoms and grass. The shank is made out of a high tensile steel capable of withstanding high loads. It is similar in design to the Roc... | Anchor | Wikipedia | 459 | 1358 | https://en.wikipedia.org/wiki/Anchor | Technology | Naval transport | null |
Permanent anchors
These are used where the vessel is permanently or semi-permanently sited, for example in the case of lightvessels or channel marker buoys. The anchor needs to hold the vessel in all weathers, including the most severe storm, but needs to be lifted only occasionally, at most – for example, only if the... | Anchor | Wikipedia | 501 | 1358 | https://en.wikipedia.org/wiki/Anchor | Technology | Naval transport | null |
A deadweight is an anchor that relies solely on being a heavy weight. It is usually just a large block of concrete or stone at the end of the chain. Its holding power is defined by its weight underwater (i.e., taking its buoyancy into account) regardless of the type of seabed, although suction can increase this if it b... | Anchor | Wikipedia | 409 | 1358 | https://en.wikipedia.org/wiki/Anchor | Technology | Naval transport | null |
Vessels may carry a number of anchors: bower anchors are the main anchors used by a vessel and normally carried at the bow of the vessel. A kedge anchor is a light anchor used for warping an anchor, also known as kedging, or more commonly on yachts for mooring quickly or in benign conditions. A stream anchor, which ... | Anchor | Wikipedia | 487 | 1358 | https://en.wikipedia.org/wiki/Anchor | Technology | Naval transport | null |
Being strong and elastic, nylon rope is the most suitable as an anchor rode. Polyester (terylene) is stronger but less elastic than nylon. Both materials sink, so they avoid fouling other craft in crowded anchorages and do not absorb much water. Neither breaks down quickly in sunlight. Elasticity helps absorb shock loa... | Anchor | Wikipedia | 511 | 1358 | https://en.wikipedia.org/wiki/Anchor | Technology | Naval transport | null |
In moderate conditions, the ratio of rode to water depth should be 4:1 – where there is sufficient swing-room, a greater scope is always better. In rougher conditions it should be up to twice this with the extra length giving more stretch and a smaller angle to the bottom to resist the anchor breaking out. For example... | Anchor | Wikipedia | 420 | 1358 | https://en.wikipedia.org/wiki/Anchor | Technology | Naval transport | null |
A major disadvantage of the concept of scope is that it does not take into account the fact that a chain is forming a catenary when hanging between two points (i.e., bow roller and the point where the chain hits the seabed), and thus is a non-linear curve (in fact, a cosh() function), whereas scope is a linear function... | Anchor | Wikipedia | 346 | 1358 | https://en.wikipedia.org/wiki/Anchor | Technology | Naval transport | null |
Ammonia is an inorganic chemical compound of nitrogen and hydrogen with the formula . A stable binary hydride and the simplest pnictogen hydride, ammonia is a colourless gas with a distinctive pungent smell. Biologically, it is a common nitrogenous waste, and it contributes significantly to the nutritional needs of ter... | Ammonia | Wikipedia | 471 | 1365 | https://en.wikipedia.org/wiki/Ammonia | Physical sciences | Inorganic compounds | null |
Ammonia is found throughout the Solar System on Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto, among other places: on smaller, icy bodies such as Pluto, ammonia can act as a geologically important antifreeze, as a mixture of water and ammonia can have a melting point as low as if the ammonia concentration is high ... | Ammonia | Wikipedia | 430 | 1365 | https://en.wikipedia.org/wiki/Ammonia | Physical sciences | Inorganic compounds | null |
Liquid ammonia is a widely studied nonaqueous ionising solvent. Its most conspicuous property is its ability to dissolve alkali metals to form highly coloured, electrically conductive solutions containing solvated electrons. Apart from these remarkable solutions, much of the chemistry in liquid ammonia can be classifie... | Ammonia | Wikipedia | 422 | 1365 | https://en.wikipedia.org/wiki/Ammonia | Physical sciences | Inorganic compounds | null |
The range of thermodynamic stability of liquid ammonia solutions is very narrow, as the potential for oxidation to dinitrogen, E° (), is only +0.04 V. In practice, both oxidation to dinitrogen and reduction to dihydrogen are slow. This is particularly true of reducing solutions: the solutions of the alkali metals menti... | Ammonia | Wikipedia | 502 | 1365 | https://en.wikipedia.org/wiki/Ammonia | Physical sciences | Inorganic compounds | null |
Amphotericity
One of the most characteristic properties of ammonia is its basicity. Ammonia is considered to be a weak base. It combines with acids to form ammonium salts; thus, with hydrochloric acid it forms ammonium chloride (sal ammoniac); with nitric acid, ammonium nitrate, etc. Perfectly dry ammonia gas will not... | Ammonia | Wikipedia | 461 | 1365 | https://en.wikipedia.org/wiki/Ammonia | Physical sciences | Inorganic compounds | null |
The standard enthalpy change of combustion, ΔH°c, expressed per mole of ammonia and with condensation of the water formed, is −382.81 kJ/mol. Dinitrogen is the thermodynamic product of combustion: all nitrogen oxides are unstable with respect to and , which is the principle behind the catalytic converter. Nitrogen oxi... | Ammonia | Wikipedia | 505 | 1365 | https://en.wikipedia.org/wiki/Ammonia | Physical sciences | Inorganic compounds | null |
Amino acids, using Strecker amino-acid synthesis
Acrylonitrile, in the Sohio process
Other organonitrogen compounds include alprazolam, ethanolamine, ethyl carbamate and hexamethylenetetramine.
Precursor to inorganic nitrogenous compounds
Nitric acid is generated via the Ostwald process by oxidation of ammonia with ... | Ammonia | Wikipedia | 507 | 1365 | https://en.wikipedia.org/wiki/Ammonia | Physical sciences | Inorganic compounds | null |
Ammonia and ammonium salts can be readily detected, in very minute traces, by the addition of Nessler's solution, which gives a distinct yellow colouration in the presence of the slightest trace of ammonia or ammonium salts. The amount of ammonia in ammonium salts can be estimated quantitatively by distillation of the ... | Ammonia | Wikipedia | 436 | 1365 | https://en.wikipedia.org/wiki/Ammonia | Physical sciences | Inorganic compounds | null |
The ancient Greek historian Herodotus mentioned that there were outcrops of salt in an area of Libya that was inhabited by a people called the 'Ammonians' (now the Siwa oasis in northwestern Egypt, where salt lakes still exist). The Greek geographer Strabo also mentioned the salt from this region. However, the ancient ... | Ammonia | Wikipedia | 485 | 1365 | https://en.wikipedia.org/wiki/Ammonia | Physical sciences | Inorganic compounds | null |
The production of ammonia from nitrogen in the air (and hydrogen) was invented by Fritz Haber and Robert LeRossignol. The patent was sent in 1909 (USPTO Nr 1,202,995) and awarded in 1916. Later, Carl Bosch developed the industrial method for ammonia production (Haber–Bosch process). It was first used on an industrial s... | Ammonia | Wikipedia | 472 | 1365 | https://en.wikipedia.org/wiki/Ammonia | Physical sciences | Inorganic compounds | null |
Ammonia coolant is also used in the radiators aboard the International Space Station in loops that are used to regulate the internal temperature and enable temperature-dependent experiments. The ammonia is under sufficient pressure to remain liquid throughout the process. Single-phase ammonia cooling systems also serve... | Ammonia | Wikipedia | 446 | 1365 | https://en.wikipedia.org/wiki/Ammonia | Physical sciences | Inorganic compounds | null |
Ammonia can be converted back to hydrogen to be used to power hydrogen fuel cells, or it may be used directly within high-temperature solid oxide direct ammonia fuel cells to provide efficient power sources that do not emit greenhouse gases. Ammonia to hydrogen conversion can be achieved through the sodium amide proces... | Ammonia | Wikipedia | 419 | 1365 | https://en.wikipedia.org/wiki/Ammonia | Physical sciences | Inorganic compounds | null |
In 2020, Saudi Arabia shipped 40 metric tons of liquid 'blue ammonia' to Japan for use as a fuel. It was produced as a by-product by petrochemical industries, and can be burned without giving off greenhouse gases. Its energy density by volume is nearly double that of liquid hydrogen. If the process of creating it can b... | Ammonia | Wikipedia | 453 | 1365 | https://en.wikipedia.org/wiki/Ammonia | Physical sciences | Inorganic compounds | null |
Remediation of gaseous emissions
Ammonia is used to scrub from the burning of fossil fuels, and the resulting product is converted to ammonium sulfate for use as fertiliser. Ammonia neutralises the nitrogen oxide () pollutants emitted by diesel engines. This technology, called SCR (selective catalytic reduction), rel... | Ammonia | Wikipedia | 353 | 1365 | https://en.wikipedia.org/wiki/Ammonia | Physical sciences | Inorganic compounds | null |
The US Occupational Safety and Health Administration (OSHA) has set a 15-minute exposure limit for gaseous ammonia of 35 ppm by volume in the environmental air and an 8-hour exposure limit of 25 ppm by volume. The National Institute for Occupational Safety and Health (NIOSH) recently reduced the IDLH (Immediately Dange... | Ammonia | Wikipedia | 455 | 1365 | https://en.wikipedia.org/wiki/Ammonia | Physical sciences | Inorganic compounds | null |
Coking wastewater
Ammonia is present in coking wastewater streams, as a liquid by-product of the production of coke from coal. In some cases, the ammonia is discharged to the marine environment where it acts as a pollutant. The Whyalla Steelworks in South Australia is one example of a coke-producing facility that disc... | Ammonia | Wikipedia | 482 | 1365 | https://en.wikipedia.org/wiki/Ammonia | Physical sciences | Inorganic compounds | null |
The hazards of ammonia solutions depend on the concentration: 'dilute' ammonia solutions are usually 5–10% by weight (< 5.62 mol/L); 'concentrated' solutions are usually prepared at >25% by weight. A 25% (by weight) solution has a density of 0.907 g/cm3, and a solution that has a lower density will be more concentrated... | Ammonia | Wikipedia | 461 | 1365 | https://en.wikipedia.org/wiki/Ammonia | Physical sciences | Inorganic compounds | null |
Ammonia reacts violently with the halogens. Nitrogen triiodide, a primary high explosive, is formed when ammonia comes in contact with iodine. Ammonia causes the explosive polymerisation of ethylene oxide. It also forms explosive fulminating compounds with compounds of gold, silver, mercury, germanium or tellurium, and... | Ammonia | Wikipedia | 473 | 1365 | https://en.wikipedia.org/wiki/Ammonia | Physical sciences | Inorganic compounds | null |
In 2020, a solvent-agnostic gas diffusion electrode was shown to improve nitrogen transport to the reactive lithium. production rates of up to and Faradaic efficiencies of up to 47.5 ± 4% at ambient temperature and 1 bar pressure were achieved.
In 2021, it was demonstrated that ethanol could be replaced with a tetra... | Ammonia | Wikipedia | 459 | 1365 | https://en.wikipedia.org/wiki/Ammonia | Physical sciences | Inorganic compounds | null |
Biosynthesis
In certain organisms, ammonia is produced from atmospheric nitrogen by enzymes called nitrogenases. The overall process is called nitrogen fixation. Intense effort has been directed toward understanding the mechanism of biological nitrogen fixation. The scientific interest in this problem is motivated by ... | Ammonia | Wikipedia | 418 | 1365 | https://en.wikipedia.org/wiki/Ammonia | Physical sciences | Inorganic compounds | null |
Ammonium ions are a toxic waste product of metabolism in animals. In fish and aquatic invertebrates, it is excreted directly into the water. In mammals, sharks, and amphibians, it is converted in the urea cycle to urea, which is less toxic and can be stored more efficiently. In birds, reptiles, and terrestrial snails, ... | Ammonia | Wikipedia | 447 | 1365 | https://en.wikipedia.org/wiki/Ammonia | Physical sciences | Inorganic compounds | null |
Interstellar formation mechanisms
The interstellar abundance for ammonia has been measured for a variety of environments. The []/[] ratio has been estimated to range from 10−7 in small dark clouds up to 10−5 in the dense core of the Orion molecular cloud complex. Although a total of 18 total production routes have bee... | Ammonia | Wikipedia | 469 | 1365 | https://en.wikipedia.org/wiki/Ammonia | Physical sciences | Inorganic compounds | null |
Single antenna detections
Radio observations of from the Effelsberg 100-m Radio Telescope reveal that the ammonia line is separated into two components–a background ridge and an unresolved core. The background corresponds well with the locations previously detected CO. The 25 m Chilbolton telescope in England detecte... | Ammonia | Wikipedia | 475 | 1365 | https://en.wikipedia.org/wiki/Ammonia | Physical sciences | Inorganic compounds | null |
A spectrum of the disk of Jupiter was obtained from the Kuiper Airborne Observatory, covering the 100 to 300 cm−1 spectral range. Analysis of the spectrum provides information on global mean properties of ammonia gas and an ammonia ice haze.
A total of 149 dark cloud positions were surveyed for evidence of 'dense core... | Ammonia | Wikipedia | 392 | 1365 | https://en.wikipedia.org/wiki/Ammonia | Physical sciences | Inorganic compounds | null |
UC HII regions
Ultra-compact HII regions are among the best tracers of high-mass star formation. The dense material surrounding UCHII regions is likely primarily molecular. Since a complete study of massive star formation necessarily involves the cloud from which the star formed, ammonia is an invaluable tool in under... | Ammonia | Wikipedia | 239 | 1365 | https://en.wikipedia.org/wiki/Ammonia | Physical sciences | Inorganic compounds | null |
Amethyst is a violet variety of quartz. The name comes from the Koine Greek from - , "not" and (Ancient Greek) / (Modern Greek), "intoxicate", a reference to the belief that the stone protected its owner from drunkenness. Ancient Greeks wore amethyst and carved drinking vessels from it in the belief that it would... | Amethyst | Wikipedia | 433 | 1366 | https://en.wikipedia.org/wiki/Amethyst | Physical sciences | Silicate minerals | Earth science |
Amethyst frequently shows color zoning, with the most intense color typically found at the crystal terminations. One of gem cutters' tasks is to make a finished product with even color. Sometimes, only a thin layer of a natural, uncut amethyst is violet colored, or the color is very uneven. The uncut gem may have only ... | Amethyst | Wikipedia | 500 | 1366 | https://en.wikipedia.org/wiki/Amethyst | Physical sciences | Silicate minerals | Earth science |
Amethyst is also found and mined in South Korea. The large opencast amethyst vein at Maissau, Lower Austria, was historically important, but is no longer included among significant producers. Much fine amethyst comes from Russia, especially near Mursinka in the Ekaterinburg district, where it occurs in drusy cavities i... | Amethyst | Wikipedia | 485 | 1366 | https://en.wikipedia.org/wiki/Amethyst | Physical sciences | Silicate minerals | Earth science |
Synthetic amethyst is made to imitate the best quality amethyst. Its chemical and physical properties are the same as those of natural amethyst, and it cannot be differentiated with absolute certainty without advanced gemmological testing (which is often cost-prohibitive). One test based on "Brazil law twinning" (a for... | Amethyst | Wikipedia | 421 | 1366 | https://en.wikipedia.org/wiki/Amethyst | Physical sciences | Silicate minerals | Earth science |
Variations of the story include that Dionysus had been insulted by a mortal and swore to slay the next mortal who crossed his path, creating fierce tigers to carry out his wrath. The mortal turned out to be a beautiful young woman, Amethystos, who was on her way to pay tribute to Artemis. Her life was spared by Artemis... | Amethyst | Wikipedia | 483 | 1366 | https://en.wikipedia.org/wiki/Amethyst | Physical sciences | Silicate minerals | Earth science |
Amethyst has a good hardness, and handling it with proper care will prevent any damage to the stone. Amethyst is sensitive to strong heat and may lose or change its colour when exposed to prolonged heat or light. Polishing the stone or cleaning it by ultrasonic or steamer must be done with caution. | Amethyst | Wikipedia | 63 | 1366 | https://en.wikipedia.org/wiki/Amethyst | Physical sciences | Silicate minerals | Earth science |
In computer programming, assembly language (alternatively assembler language or symbolic machine code), often referred to simply as assembly and commonly abbreviated as ASM or asm, is any low-level programming language with a very strong correspondence between the instructions in the language and the architecture's ma... | Assembly language | Wikipedia | 389 | 1368 | https://en.wikipedia.org/wiki/Assembly%20language | Technology | Programming | null |
In the first decades of computing, it was commonplace for both systems programming and application programming to take place entirely in assembly language. While still irreplaceable for some purposes, the majority of programming is now conducted in higher-level interpreted and compiled languages. In "No Silver Bullet... | Assembly language | Wikipedia | 488 | 1368 | https://en.wikipedia.org/wiki/Assembly%20language | Technology | Programming | null |
Terminology
A macro assembler is an assembler that includes a macroinstruction facility so that (parameterized) assembly language text can be represented by a name, and that name can be used to insert the expanded text into other code.
Open code refers to any assembler input outside of a macro definition.
A cross as... | Assembly language | Wikipedia | 475 | 1368 | https://en.wikipedia.org/wiki/Assembly%20language | Technology | Programming | null |
Assembler
An assembler program creates object code by translating combinations of mnemonics and syntax for operations and addressing modes into their numerical equivalents. This representation typically includes an operation code ("opcode") as well as other control bits and data. The assembler also calculates constant ... | Assembly language | Wikipedia | 481 | 1368 | https://en.wikipedia.org/wiki/Assembly%20language | Technology | Programming | null |
Number of passes
There are two types of assemblers based on how many passes through the source are needed (how many times the assembler reads the source) to produce the object file.
One-pass assemblers process the source code once. For symbols used before they are defined, the assembler will emit "errata" after the e... | Assembly language | Wikipedia | 506 | 1368 | https://en.wikipedia.org/wiki/Assembly%20language | Technology | Programming | null |
High-level assemblers
More sophisticated high-level assemblers provide language abstractions such as:
High-level procedure/function declarations and invocations
Advanced control structures (IF/THEN/ELSE, SWITCH)
High-level abstract data types, including structures/records, unions, classes, and sets
Sophisticated ma... | Assembly language | Wikipedia | 276 | 1368 | https://en.wikipedia.org/wiki/Assembly%20language | Technology | Programming | null |
For example, the instruction below tells an x86/IA-32 processor to move an immediate 8-bit value into a register. The binary code for this instruction is 10110 followed by a 3-bit identifier for which register to use. The identifier for the AL register is 000, so the following machine code loads the AL register with th... | Assembly language | Wikipedia | 363 | 1368 | https://en.wikipedia.org/wiki/Assembly%20language | Technology | Programming | null |
If the same mnemonic is used for different instructions, that means that the mnemonic corresponds to several different binary instruction codes, excluding data (e.g. the 61h in this example), depending on the operands that follow the mnemonic. For example, for the x86/IA-32 CPUs, the Intel assembly language syntax MOV... | Assembly language | Wikipedia | 435 | 1368 | https://en.wikipedia.org/wiki/Assembly%20language | Technology | Programming | null |
Returning to the original example, while the x86 opcode 10110000 (B0) copies an 8-bit value into the AL register, 10110001 (B1) moves it into CL and 10110010 (B2) does so into DL. Assembly language examples for these follow.
MOV AL, 1h ; Load AL with immediate value 1
MOV CL, 2h ; Load CL with immediate v... | Assembly language | Wikipedia | 248 | 1368 | https://en.wikipedia.org/wiki/Assembly%20language | Technology | Programming | null |
Transforming assembly language into machine code is the job of an assembler, and the reverse can at least partially be achieved by a disassembler. Unlike high-level languages, there is a one-to-one correspondence between many simple assembly statements and machine language instructions. However, in some cases, an assem... | Assembly language | Wikipedia | 409 | 1368 | https://en.wikipedia.org/wiki/Assembly%20language | Technology | Programming | null |
Two examples of CPUs that have two different sets of mnemonics are the Intel 8080 family and the Intel 8086/8088. Because Intel claimed copyright on its assembly language mnemonics (on each page of their documentation published in the 1970s and early 1980s, at least), some companies that independently produced CPUs co... | Assembly language | Wikipedia | 380 | 1368 | https://en.wikipedia.org/wiki/Assembly%20language | Technology | Programming | null |
"Hello, world!" on x86 Linux
In 32-bit assembly language for Linux on an x86 processor, "Hello, world!" can be printed like this.
section .text
global _start
_start:
mov edx,len ; length of string, third argument to write()
mov ecx,msg ; address of string, second argument to write()
mov ... | Assembly language | Wikipedia | 494 | 1368 | https://en.wikipedia.org/wiki/Assembly%20language | Technology | Programming | null |
Extended mnemonics are often used to support specialized uses of instructions, often for purposes not obvious from the instruction name. For example, many CPU's do not have an explicit NOP instruction, but do have instructions that can be used for the purpose. In 8086 CPUs the instruction is used for , with being a p... | Assembly language | Wikipedia | 495 | 1368 | https://en.wikipedia.org/wiki/Assembly%20language | Technology | Programming | null |
Symbolic assemblers let programmers associate arbitrary names (labels or symbols) with memory locations and various constants. Usually, every constant and variable is given a name so instructions can reference those locations by name, thus promoting self-documenting code. In executable code, the name of each subroutine... | Assembly language | Wikipedia | 464 | 1368 | https://en.wikipedia.org/wiki/Assembly%20language | Technology | Programming | null |
Macro assemblers typically have directives to, e.g., define macros, define variables, set variables to the result of an arithmetic, logical or string expression, iterate, conditionally generate code. Some of those directives may be restricted to use within a macro definition, e.g., MEXIT in HLASM, while others may be p... | Assembly language | Wikipedia | 263 | 1368 | https://en.wikipedia.org/wiki/Assembly%20language | Technology | Programming | null |
Macro assemblers often allow macros to take parameters. Some assemblers include quite sophisticated macro languages, incorporating such high-level language elements as optional parameters, symbolic variables, conditionals, string manipulation, and arithmetic operations, all usable during the execution of a given macro,... | Assembly language | Wikipedia | 408 | 1368 | https://en.wikipedia.org/wiki/Assembly%20language | Technology | Programming | null |
It is also possible to use solely the macro processing abilities of an assembler to generate code written in completely different languages, for example, to generate a version of a program in COBOL using a pure macro assembler program containing lines of COBOL code inside assembly time operators instructing the assembl... | Assembly language | Wikipedia | 438 | 1368 | https://en.wikipedia.org/wiki/Assembly%20language | Technology | Programming | null |
Packages of macros have been written providing structured programming elements to encode execution flow. The earliest example of this approach was in the Concept-14 macro set, originally proposed by Harlan Mills (March 1970), and implemented by Marvin Kessler at IBM's Federal Systems Division, which provided IF/ELSE/EN... | Assembly language | Wikipedia | 402 | 1368 | https://en.wikipedia.org/wiki/Assembly%20language | Technology | Programming | null |
.code
demomain:
REPEAT 20
switch rv(nrandom, 9) ; generate a number between 0 and 8
mov ecx, 7
case 0
print "case 0"
case ecx ; in contrast to most other programming languages,
print "case 7" ; the Masm32 switch allows "variable cases"
case 1 .. 3
.if eax==1
print "case 1"
.elseif eax==2
print ... | Assembly language | Wikipedia | 389 | 1368 | https://en.wikipedia.org/wiki/Assembly%20language | Technology | Programming | null |
Assembly languages eliminated much of the error-prone, tedious, and time-consuming first-generation programming needed with the earliest computers, freeing programmers from tedium such as remembering numeric codes and calculating addresses. They were once widely used for all sorts of programming. By the late 1950s thei... | Assembly language | Wikipedia | 478 | 1368 | https://en.wikipedia.org/wiki/Assembly%20language | Technology | Programming | null |
, the TIOBE index of programming language popularity ranks assembly language at 11, ahead of Visual Basic, for example. Assembler can be used to optimize for speed or optimize for size. In the case of speed optimization, modern optimizing compilers are claimed to render high-level languages into code that can run as fa... | Assembly language | Wikipedia | 172 | 1368 | https://en.wikipedia.org/wiki/Assembly%20language | Technology | Programming | null |
Writing code for systems with that have limited high-level language options such as the Atari 2600, Commodore 64, and graphing calculators. Programs for these computers of the 1970s and 1980s are often written in the context of demoscene or retrogaming subcultures.
Code that must interact directly with the hardware, ... | Assembly language | Wikipedia | 511 | 1368 | https://en.wikipedia.org/wiki/Assembly%20language | Technology | Programming | null |
Situations where complete control over the environment is required, in extremely high-security situations where nothing can be taken for granted.
Computer viruses, bootloaders, certain device drivers, or other items very close to the hardware or low-level operating system.
Instruction set simulators for monitoring, t... | Assembly language | Wikipedia | 181 | 1368 | https://en.wikipedia.org/wiki/Assembly%20language | Technology | Programming | null |
Assembly language is still taught in most computer science and electronic engineering programs. Although few programmers today regularly work with assembly language as a tool, the underlying concepts remain important. Such fundamental topics as binary arithmetic, memory allocation, stack processing, character set encod... | Assembly language | Wikipedia | 157 | 1368 | https://en.wikipedia.org/wiki/Assembly%20language | Technology | Programming | null |
Typical applications
Assembly language is typically used in a system's boot code, the low-level code that initializes and tests the system hardware prior to booting the operating system and is often stored in ROM. (BIOS on IBM-compatible PC systems and CP/M is an example.)
Assembly language is often used for low-leve... | Assembly language | Wikipedia | 367 | 1368 | https://en.wikipedia.org/wiki/Assembly%20language | Technology | Programming | null |
Amber is fossilized tree resin. Examples of it have been appreciated for its color and natural beauty since the Neolithic times, and worked as a gemstone since antiquity. Amber is used in jewelry and as a healing agent in folk medicine.
There are five classes of amber, defined on the basis of their chemical constituen... | Amber | Wikipedia | 471 | 1372 | https://en.wikipedia.org/wiki/Amber | Physical sciences | Organic gemstones | null |
Varietal names
A number of regional and varietal names have been applied to ambers over the centuries, including Allingite, Beckerite, Gedanite, Kochenite, Krantzite, and Stantienite.
History
Theophrastus discussed amber in the 4th century BCE, as did Pytheas (), whose work "On the Ocean" is lost, but was referenced ... | Amber | Wikipedia | 512 | 1372 | https://en.wikipedia.org/wiki/Amber | Physical sciences | Organic gemstones | null |
The Romans traded for amber from the shores of the southern Baltic at least as far back as the time of Nero.
Amber has a long history of use in China, with the first written record from 200 BCE. Early in the 19th century, the first reports of amber found in North America came from discoveries in New Jersey along Cross... | Amber | Wikipedia | 347 | 1372 | https://en.wikipedia.org/wiki/Amber | Physical sciences | Organic gemstones | null |
Molecular polymerization, resulting from high pressures and temperatures produced by overlying sediment, transforms the resin first into copal. Sustained heat and pressure drives off terpenes and results in the formation of amber. For this to happen, the resin must be resistant to decay. Many trees produce resin, but i... | Amber | Wikipedia | 467 | 1372 | https://en.wikipedia.org/wiki/Amber | Physical sciences | Organic gemstones | null |
Pieces of amber torn from the seafloor are cast up by the waves and collected by hand, dredging, or diving. Elsewhere, amber is mined, both in open works and underground galleries. Then nodules of blue earth have to be removed and an opaque crust must be cleaned off, which can be done in revolving barrels containing sa... | Amber | Wikipedia | 468 | 1372 | https://en.wikipedia.org/wiki/Amber | Physical sciences | Organic gemstones | null |
Amber occurs in a range of different colors. As well as the usual yellow-orange-brown that is associated with the color "amber", amber can range from a whitish color through a pale lemon yellow, to brown and almost black. Other uncommon colors include red amber (sometimes known as "cherry amber"), green amber, and even... | Amber | Wikipedia | 470 | 1372 | https://en.wikipedia.org/wiki/Amber | Physical sciences | Organic gemstones | null |
Classification
Amber can be classified into several forms. Most fundamentally, there are two types of plant resin with the potential for fossilization. Terpenoids, produced by conifers and angiosperms, consist of ring structures formed of isoprene (C5H8) units. Phenolic resins are today only produced by angiosperms, an... | Amber | Wikipedia | 499 | 1372 | https://en.wikipedia.org/wiki/Amber | Physical sciences | Organic gemstones | null |
Class Ic is mainly based on enantio-labdatrienonic acids, such as ozic and zanzibaric acids. Its most familiar representative is Dominican amber,. which is mostly transparent and often contains a higher number of fossil inclusions. This has enabled the detailed reconstruction of the ecosystem of a long-vanished tropica... | Amber | Wikipedia | 469 | 1372 | https://en.wikipedia.org/wiki/Amber | Physical sciences | Organic gemstones | null |
In Lebanon, more than 450 outcrops of Lower Cretaceous amber were discovered by Dany Azar, a Lebanese paleontologist and entomologist. Among these outcrops, 20 have yielded biological inclusions comprising the oldest representatives of several recent families of terrestrial arthropods. Even older Jurassic amber has bee... | Amber | Wikipedia | 371 | 1372 | https://en.wikipedia.org/wiki/Amber | Physical sciences | Organic gemstones | null |
Amber is a unique preservational mode, preserving otherwise unfossilizable parts of organisms; as such it is helpful in the reconstruction of ecosystems as well as organisms; the chemical composition of the resin, however, is of limited utility in reconstructing the phylogenetic affinity of the resin producer. Amber so... | Amber | Wikipedia | 491 | 1372 | https://en.wikipedia.org/wiki/Amber | Physical sciences | Organic gemstones | null |
Historical medicinal uses
Amber has long been used in folk medicine for its purported healing properties. Amber and extracts were used from the time of Hippocrates in ancient Greece for a wide variety of treatments through the Middle Ages and up until the early twentieth century. Traditional Chinese medicine uses amber... | Amber | Wikipedia | 435 | 1372 | https://en.wikipedia.org/wiki/Amber | Physical sciences | Organic gemstones | null |
Young resins used as imitations:
Kauri resin from Agathis australis trees in New Zealand.
The copals (subfossil resins). The African and American (Colombia) copals from Leguminosae trees family (genus Hymenaea). Amber of the Dominican or Mexican type (Class I of fossil resins). Copals from Manilia (Indonesia) and fro... | Amber | Wikipedia | 140 | 1372 | https://en.wikipedia.org/wiki/Amber | Physical sciences | Organic gemstones | null |
Plastics used as imitations:
Stained glass (inorganic material) and other ceramic materials
Celluloid
Cellulose nitrate (first obtained in 1833) — a product of treatment of cellulose with nitration mixture.
Acetylcellulose (not in the use at present)
Galalith or "artificial horn" (condensation product of casein an... | Amber | Wikipedia | 416 | 1372 | https://en.wikipedia.org/wiki/Amber | Physical sciences | Organic gemstones | null |
Alders are trees of the genus Alnus in the birch family Betulaceae. The genus includes about 35 species of monoecious trees and shrubs, a few reaching a large size, distributed throughout the north temperate zone with a few species extending into Central America, as well as the northern and southern Andes.
Description... | Alder | Wikipedia | 485 | 1383 | https://en.wikipedia.org/wiki/Alder | Biology and health sciences | Fagales | null |
Subgenus Clethropsis
Trees or shrubs with stalked shoot buds, male and female catkins produced in autumn (fall) and expanding and pollinating then, three species:
Alnus formosana
Alnus maritima
Alnus nitida
Subgenus Alnobetula
Shrubs with shoot buds not stalked, male and female catkins produced in late spring... | Alder | Wikipedia | 497 | 1383 | https://en.wikipedia.org/wiki/Alder | Biology and health sciences | Fagales | null |
Alnus × aschersoniana
Alnus × koehnei
Alnus × ljungeri
Alnus × purpusii
Alnus × silesiaca
Alnus × spaethii (A. japonica × A. subcordata)
Fossil record
The oldest fossil pollen that can be identified as Alnus is from northern Bohemia, dating to the late Paleocene, around 58 million years ago.
†Alnus fairi ... | Alder | Wikipedia | 387 | 1383 | https://en.wikipedia.org/wiki/Alder | Biology and health sciences | Fagales | null |
Alder is particularly noted for its important symbiotic relationship with Frankia alni, an actinomycete, filamentous, nitrogen-fixing bacterium. This bacterium is found in root nodules, which may be as large as a human fist, with many small lobes, and light brown in colour. The bacterium absorbs nitrogen from the air a... | Alder | Wikipedia | 508 | 1383 | https://en.wikipedia.org/wiki/Alder | Biology and health sciences | Fagales | null |
The catkins of some alder species have a degree of edibility, and may be rich in protein. Reported to have a bitter and unpleasant taste, they are more useful for survival purposes. The wood of certain alder species is often used to smoke various food items such as coffee, salmon, and other seafood.
Alder is notably s... | Alder | Wikipedia | 494 | 1383 | https://en.wikipedia.org/wiki/Alder | Biology and health sciences | Fagales | null |
Culture
Ermanno Olmi's movie The Tree of Wooden Clogs (L' Albero Degli Zoccoli, 1978) refers in its title to alder, typically used to make clogs as in this movie's plot. | Alder | Wikipedia | 54 | 1383 | https://en.wikipedia.org/wiki/Alder | Biology and health sciences | Fagales | null |
Algol , designated Beta Persei (β Persei, abbreviated Beta Per, β Per), known colloquially as the Demon Star, is a bright multiple star in the constellation of Perseus and one of the first non-nova variable stars to be discovered.
Algol is a three-star system, consisting of Beta Persei Aa1, Aa2, and Ab – in which the ... | Algol | Wikipedia | 433 | 1394 | https://en.wikipedia.org/wiki/Algol | Physical sciences | Notable stars | Astronomy |
In 1881, the Harvard astronomer Edward Charles Pickering presented evidence that Algol was actually an eclipsing binary. This was confirmed a few years later, in 1889, when the Potsdam astronomer Hermann Carl Vogel found periodic doppler shifts in the spectrum of Algol, inferring variations in the radial velocity of th... | Algol | Wikipedia | 485 | 1394 | https://en.wikipedia.org/wiki/Algol | Physical sciences | Notable stars | Astronomy |
Studies of Algol led to the Algol paradox in the theory of stellar evolution: although components of a binary star form at the same time, and massive stars evolve much faster than the less massive stars, the more massive component Algol Aa1 is still in the main sequence, but the less massive Algol Aa2 is a subgiant sta... | Algol | Wikipedia | 510 | 1394 | https://en.wikipedia.org/wiki/Algol | Physical sciences | Notable stars | Astronomy |
The official name Algol
The name Algol derives from Arabic raʾs al-ghūl : head (raʾs) of the ogre (al-ghūl) (see "ghoul"). The English name Demon Star was taken from the Arabic name. In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN) to catalog and standardize proper names for... | Algol | Wikipedia | 509 | 1394 | https://en.wikipedia.org/wiki/Algol | Physical sciences | Notable stars | Astronomy |
Listed are the first eclipse dates and times of each month, with all times in UT. β Persei Aa2 eclipses β Persei Aa1 every 2.867321 days (2 days 20 hours 49 min). To determine subsequent eclipses, add this interval to each listed date and time. For example, the Jan 2 eclipse at 8h will result in consecutive eclipse tim... | Algol | Wikipedia | 237 | 1394 | https://en.wikipedia.org/wiki/Algol | Physical sciences | Notable stars | Astronomy |
In chemistry, amines (, ) are compounds and functional groups that contain a basic nitrogen atom with a lone pair. Formally, amines are derivatives of ammonia ((in which the bond angle between the nitrogen and hydrogen is 170°), wherein one or more hydrogen atoms have been replaced by a substituent such as an alkyl or... | Amine | Wikipedia | 354 | 1412 | https://en.wikipedia.org/wiki/Amine | Physical sciences | Carbon–nitrogen bond | null |
Primary (1°) amines—Primary amines arise when one of three hydrogen atoms in ammonia is replaced by an alkyl or aromatic group. Important primary alkyl amines include methylamine, most amino acids, and the buffering agent tris, while primary aromatic amines include aniline.
Secondary (2°) amines—Secondary amines have t... | Amine | Wikipedia | 489 | 1412 | https://en.wikipedia.org/wiki/Amine | Physical sciences | Carbon–nitrogen bond | null |
The nitrogen atom features a lone electron pair that can bind H+ to form an ammonium ion R3NH+. The lone electron pair is represented in this article by two dots above or next to the N. The water solubility of simple amines is enhanced by hydrogen bonding involving these lone electron pairs. Typically salts of ammoniu... | Amine | Wikipedia | 462 | 1412 | https://en.wikipedia.org/wiki/Amine | Physical sciences | Carbon–nitrogen bond | null |
Amines of the type NHRR' and NRR′R″ are chiral: the nitrogen center bears four substituents counting the lone pair. Because of the low barrier to inversion, amines of the type NHRR' cannot be obtained in optical purity. For chiral tertiary amines, NRR′R″ can only be resolved when the R, R', and R″ groups are constrain... | Amine | Wikipedia | 391 | 1412 | https://en.wikipedia.org/wiki/Amine | Physical sciences | Carbon–nitrogen bond | null |
Solvation effects
Solvation significantly affects the basicity of amines. N-H groups strongly interact with water, especially in ammonium ions. Consequently, the basicity of ammonia is enhanced by 1011 by solvation. The intrinsic basicity of amines, i.e. the situation where solvation is unimportant, has been evaluated... | Amine | Wikipedia | 487 | 1412 | https://en.wikipedia.org/wiki/Amine | Physical sciences | Carbon–nitrogen bond | null |
From alkenes
Disubstituted alkenes react with HCN in the presence of strong acids to give formamides, which can be decarbonylated. This method, the Ritter reaction, is used industrially to produce tertiary amines such as tert-octylamine.
Hydroamination of alkenes is also widely practiced. The reaction is catalyzed b... | Amine | Wikipedia | 509 | 1412 | https://en.wikipedia.org/wiki/Amine | Physical sciences | Carbon–nitrogen bond | null |
Diazotization
Amines reacts with nitrous acid to give diazonium salts. The alkyl diazonium salts are of little importance because they are too unstable. The most important members are derivatives of aromatic amines such as aniline ("phenylamine") (A = aryl or naphthyl):
ANH2 + HNO2 + HX -> AN2+ + X- + 2 H2O
Anilines a... | Amine | Wikipedia | 428 | 1412 | https://en.wikipedia.org/wiki/Amine | Physical sciences | Carbon–nitrogen bond | null |
Biological activity
Amines are ubiquitous in biology. The breakdown of amino acids releases amines, famously in the case of decaying fish which smell of trimethylamine. Many neurotransmitters are amines, including epinephrine, norepinephrine, dopamine, serotonin, and histamine. Protonated amino groups () are the most c... | Amine | Wikipedia | 318 | 1412 | https://en.wikipedia.org/wiki/Amine | Physical sciences | Carbon–nitrogen bond | null |
Drugs
Most drugs and drug candidates contain amine functional groups:
Chlorpheniramine is an antihistamine that helps to relieve allergic disorders due to cold, hay fever, itchy skin, insect bites and stings.
Chlorpromazine is a tranquilizer that sedates without inducing sleep. It is used to relieve anxiety, exciteme... | Amine | Wikipedia | 426 | 1412 | https://en.wikipedia.org/wiki/Amine | Physical sciences | Carbon–nitrogen bond | null |
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