omniomni/omni-engineering huggingface dataset:
Gibbs–Helmholtz equation. The Gibbs–Helmholtz equation is a thermodynamic equation used to calculate changes in the Gibbs free energy of a system as a function of temperature. It was originally presented in an 1882 paper entitled "Die Thermodynamik chemischer Vorgänge" by Hermann von Helmholtz. It describes how the Gibbs free energy, which was presented originally by Josiah Willard Gibbs, varies with temperature. It was derived by Helmholtz first, and Gibbs derived it only 6 years later. The attribution to Gibbs goes back to Wilhelm Ostwald, who first translated Gibbs' monograph into German and promoted it in Europe.

The equation is:

where H is the enthalpy, T the absolute temperature and G the Gibbs free energy of the system, all at constant pressure p. The equation states that the change in the G/T ratio at constant pressure as a result of an infinitesimally small change in temperature is a factor H/T2.

Similar equations include

Chemical reactions and work

The typical applications of this equation are to chemical reactions. The equation reads:

with ΔG as the change in Gibbs energy due to reaction, and ΔH as the enthalpy of reaction (often, but not necessarily, assumed to be independent of temperature). The o denotes the use of standard states, and particularly the choice of a particular standard pressure (1 bar), to calculate ΔG and ΔH.

Integrating with respect to T (again p is constant) yields:

This equation quickly enables the calculation of the Gibbs free energy change for a chemical reaction at any temperature T2 with knowledge of just the standard Gibbs free energy change of formation and the standard enthalpy change of formation for the individual components.

Also, using the reaction isotherm equation, that is

which relates the Gibbs energy to a chemical equilibrium constant, the van 't Hoff equation can be derived.

Since the change in a system's Gibbs energy is equal to the maximum amount of non-expansion work that the system can do in a process, the Gibbs-Helmholtz equation may be used to estimate how much non-expansion work can be done by a chemical process as a function of temperature. For example, the capacity of rechargeable electric batteries can be estimated as a function of temperature using the Gibbs-Helmholtz equation.

Derivation

Background

The definition of the Gibbs function is  where  is the enthalpy defined by: 

Taking differentials of each definition to find  and , then using the fundamental thermodynamic relation (always true for reversible or irreversible processes):

where  is the entropy,  is volume, (minus sign due to reversibility, in which : work other than pressure-volume may be done and is equal to ) leads to the "reversed" form of the initial fundamental relation into a new master equation:

This is the Gibbs free energy for a closed system. The Gibbs–Helmholtz equation can be derived by this second master equation, and the chain rule for partial derivatives.

Sources

External links
 Gibbs–Helmholtz equation, by W. R. Salzman (2004).
 Gibbs-Helmholtz Equation, by P. Mander (2013)

Thermodynamic equations
Hermann von Helmholtz
Niels Ferguson. Niels T. Ferguson (born 10 December 1965, Eindhoven) is a Dutch cryptographer and consultant who currently works for Microsoft. He has worked with others, including Bruce Schneier, designing cryptographic algorithms, testing algorithms and protocols, and writing papers and books. Among the designs Ferguson has contributed to is the AES finalist block cipher algorithm Twofish as well as the stream cipher Helix and the Skein hash function.

In 1999, Niels Ferguson, together with Bruce Schneier and John Kelsey, developed the Yarrow algorithm, a Cryptographically-Secure Pseudorandom Number Generator (CSPRNG). Yarrow was later further developed by Niels Ferguson and Bruce Schneier into the Fortuna CSPRNG.

In 2001, he claimed to have broken the HDCP system that is incorporated into HD DVD and Blu-ray Discs players, similar to the DVDs Content Scramble System, but has not published his research, citing the Digital Millennium Copyright Act of 1998, which would make such publication illegal.

In 2006 he published a paper covering some of his work around Bitlocker full disk encryption at Microsoft.

At the CRYPTO 2007 conference rump session, Dan Shumow and Niels Ferguson  presented an informal paper describing a potential kleptographic backdoor in the NIST specified Dual_EC_DRBG cryptographically secure pseudorandom number generator. The kleptographic backdoor was confirmed to be real in 2013 as part of the Edward Snowden leaks.

References

External links
  Short bio at the ORD-GROUP site.
 Ferguson chooses not to publish his results because he fears being prosecuted under the Digital Millennium Copyright Act
 On the Possibility of a Back Door in the NIST SP800-90 Dual Ec Prng

Dutch cryptographers
Modern cryptographers
Microsoft employees
People from Eindhoven
1965 births
Living people
HSL. HSL may refer to:

Science, technology and computing 
 HSL (Fortran library), a numerical software library
 HSL and HSV color space
 Health and Safety Laboratory, UK
 Hormone-sensitive lipase, a protein
 Hybrid solar lighting

Transport 
 Bell HSL, a 1950s U.S. Navy antisubmarine helicopter
 Haslemere railway station in England
 Helsinki Regional Transport Authority (Helsingin seudun liikenne), Finland
 Hindustan Shipyard, in Visakhapatnam, Andhra Pradesh, India
 Hispania Líneas Aéreas, a defunct Spanish airline
 HSL Logistik, a German train operator
 Huslia Airport, in Alaska, US
 High-speed rail lines in Benelux HSL 1, HSL 2 HSL 3 HSL 4, and HSL-Zuid
 HSL-34 to HSL-94: Former US Navy helicopter Anti-submarine (Light) squadrons

Other uses 
 Hausa Sign Language, Kano, Nigeria
 Hawaiʻi Sign Language, Hawaii, United States
 Hamburg School of Logistics, now Kühne Logistics University, Germany
Staff Selection Commission Combined Higher Secondary Level Exam or CHSL/HSL, civil service examination by the Staff Selection Commission for governmental posts in India
American Rocket Society. The American Rocket Society (ARS) began its existence on 4 April 1930, under the name of the American Interplanetary Society. It was founded by science fiction writers G. Edward Pendray, David Lasser, Laurence Manning, Nathan Schachner, and others. Pendray corresponded with Willy Ley of the German rocket society, Verein für Raumschiffahrt, and visited him in 1931. The members originally conducted their own rocket experiments in New York and New Jersey. The society printed its own journal. The AIS did pioneering work in testing the design requirements of liquid-fueled rockets, with a number of successful test launches of ARS rockets occurring in this period and pointing the way to the United States space program. Its name was changed to American Rocket Society on 6 April 1934. In 1936, the American Rocket Society and its member Alfred Africano were awarded the Prix d'Astronautique by the Société astronomique de France (French Astronomical Society) in recognition of their pioneering tests with liquid fueled rockets.

The Journal of the American Rocket Society was published from 194553.

Membership increased rapidly in the 1950s as the government funded "upper air research", and by the end of the decade it had reached 21,000. In early 1963, the ARS merged with the Institute of the Aerospace Sciences to become the American Institute of Aeronautics and Astronautics (AIAA).

References and notes

Rocketry
1930 establishments in the United States
American Institute of Aeronautics and Astronautics
Scientific organizations established in 1930
Organizations disestablished in 1963
Hot-tube ignitor. A hot-tube ignitor was an early device that fit onto the cylinder head of an internal-combustion engine, used to ignite the compressed fuel/air mixture by means of a flame heating part of the tube red-hot. A hot-tube ignitor consisted of a metal or porcelain tube, closed at one end and attached to the cylinder head at the other and an adjustable burner that could be moved to position its flame at any point along the length of the tube.

Operation
The hot tube usually enters the combustion chamber at the valve block, to the side of the main cylinder bore in a side-valve, and after an ignition event remains full of a small residue of spent gasses as the piston pushes the majority of such out of the exhaust valve.  On the induction stroke, fresh charge cannot ignite arbitrarily as the hot part of the tube is shielded by these spent gasses.  On the compression stroke, fresh (unburned) fuel/air mixture is compressed in the main cylinder, which also raises the pressure in the tube and means that the spent gasses therein are forced towards its end. When compression reaches a point that the fresh fuel reaches the red-hot area of the tube, ignition occurs. On early designs, ignition timing was adjusted by adjusting the position of the red-hot spot on the tube - the burner is moved towards the far end to retard ignition, and towards the base to advance.  Most later styles used a fixed burner and varied tube lengths to change ignition timing.

Disadvantages
Hot-tube ignitors had many problems, most caused by the sudden pressure changes in the tube because of the operation of the engine and the high temperature of the tube. It was extremely difficult to find materials that were both durable enough for these conditions and inexpensive. 

Also important was never setting the burner flame where it would heat the tube white hot, which would rapidly damage the tube and could cause it to burst explosively. This mistake was made often.

The tubes used were typically 6 to 12 inches long, which tended to make them impractical for use on anything but large engines (e.g., stationary motors in factories). Tubes rarely lasted longer than a year before needing replacement, especially when the engines were fueled with high sulfur gases like unpurified producer gas or natural gas.

See also
 Hot-bulb engine
 Hot tube engine

References

Ignition systems
Operating environment. In computer software, an operating environment or integrated applications environment is the environment in which users run application software. The environment consists of a user interface provided by an applications manager and usually an application programming interface (API) to the applications manager.

An operating environment is not a full operating system, but is a form of middleware that rests between the OS and the application. For example, the first version of Microsoft Windows,  Windows 1.0, was not a full operating system, but a GUI laid over DOS albeit with an API of its own. Similarly, the IBM U2 system operates on both Unix/Linux and Windows NT. Usually the user interface is text-based or graphical, rather than a command-line interface (e.g., DOS or the Unix shell), which is often the interface of the underlying operating system.

In the mid 1980s, text-based and graphical user interface operating environments  surrounded DOS operating systems with a shell that turned the user's display into a menu-oriented "desktop" for selecting and running PC applications. These operating environment systems allow users much of the convenience of integrated software without locking them into a single package.

History

DOS operating environments 
In the mid 1980s, text-based and graphical user interface operating environments such as IBM TopView, Microsoft Windows, Digital Research's GEM Desktop, GEOS and Quarterdeck Office Systems's DESQview surrounded DOS operating systems with a shell that turned the user's display into a menu-oriented "desktop" for selecting and running PC applications. These programs were more than simple menu systems—as alternate operating environments they were substitutes for integrated programs such as Framework and Symphony, that allowed switching, windowing, and cut-and-paste operations among dedicated applications. These operating environment systems gave users much of the convenience of integrated software without locking them into a single package. Alternative operating environments made terminate-and-stay-resident pop-up utilities such as Borland Sidekick redundant. Windows provided its own version of these utilities, and placing them under central control could eliminate memory conflicts that RAM-resident utilities create.  In later versions, Windows evolved from an operating environment into a complete operating system with DOS as a bootloader (Windows 9x) and a complete operating system, Windows NT, was developed at the same time. All versions after Windows ME have been based on the Windows NT kernel.

See also 
 Desktop environment, the graphical user interface to the computer
 File manager
 Integrated environment
 Integrated development environment, a type of computer software that assists computer programmers in developing software
 Runtime environment, a virtual machine state which provides software services for processes or programs while a computer is running
 X Window System

References 

Computing terminology
Middleware
Operating system APIs
User interfaces
Observer. An observer is one who engages in observation or in watching an experiment.

Observer may also refer to:

Computer science and information theory
 In information theory, any system which receives information from an object
 State observer in control theory, a system that models a real system in order to provide an estimate of its internal state
 Observer pattern, a design pattern used in computer programming

Fiction
 Observer (novel), a 2023 science fiction novel by Robert Lanza and Nancy Kress
 Observer (video game), a cyberpunk horror video game
 Observer (Mystery Science Theater 3000), a fictional television character
 Observers, beings in the television show Fringe

Military
 Air observer, an aircrew member
 Artillery observer, a front line personnel who directs fire discipline for artillery strikes
 Observer, a non-participating officer, or umpire, tasked with observing the actions of soldiers during a field training or military exercise

Music
 "Observer", a song by Gary Numan on his album The Pleasure Principle
 "The Observer", a track from The Flaming Lips' 1999 album The Soft Bulletin
 The Observers, an alternative name for reggae session band Soul Syndicate

Publications
 Observer.com, an online-only version of the weekly newspaper The New York Observer
 Observer (APS), a member magazine of Association for Psychological Science
 The Observer (disambiguation), multiple items

Science
 Observer (general relativity)
 Observer (meteorological)
 Observer (quantum physics)
 Observer (special relativity)

Other uses
 Observer status, granted by an organization to allow a non-member limited participation
 An election observer, one who assists in election monitoring
 A game official sometimes used in the sport Ultimate
 The Observer type in the Enneagram of Personality model
Donald Alaster Macdonald (1859–1932), Australian journalist who wrote under the pseudonym 'Observer'

See also
 Observer effect (disambiguation)
 National Observer (disambiguation), a variety of publications
 The Observer (disambiguation)
 United Nations Military Observer
Hacking Matter. Hacking Matter is a 2003 book by Wil McCarthy. It deals with "programmable matter" (like colloidal films, bulk crystals, and quantum dots) that, he predicts, will someday be able mimic the properties of any natural atom, and ultimately also non-natural atoms. McCarthy predicts that programmable matter will someday change human life profoundly, and that its users will have the ability to program matter itself - to change it, from a computer, from hard to soft, from paper to stone, from fluorescent to super-reflective to invisible. In his science fiction, he calls this technology "Wellstone".

The book includes interviews with researchers who are developing the technology, describes how they are learning to control its electronic, optical, thermal, magnetic, and mechanical properties, and speculates on its future development.

References

External links
 Book home page, includes free PDF version.
 Ultimate Alchemy. This article in Wired 9.10 was expanded into this book. 
 "Beyond the Periodic Table: Artificial Atoms and Programmable Matter", Analog Science Fiction, Jan 2002

2003 non-fiction books
Futurology books
Books by Wil McCarthy
PowerOpen Environment. The PowerOpen Environment (POE), created in 1991 from the AIM alliance, is an open standard for running a Unix-based operating system on the PowerPC computer architecture.

History
The AIM alliance was announced on October 2, 1991, yielding the historic first technology partnership between Apple and IBM. One of its many lofty goals was to somehow eventually merge Apple's user-friendly graphical interface and desktop applications market with IBM's highly scalable Unix server market, allowing the two companies to enter what Apple believed to be an emerging "general desktop open systems market". This was touched upon by Apple's November 1991 announcement of A/UX 3.0. The upcoming A/UX 4.0 (never actually released) would target the PowerOpen Environment ABI, merge features of IBM's AIX variant of Unix into A/UX, and use the OSF/1 kernel from the Open Software Foundation. A/UX 3.0 would serve as an "important migration path" to this new system, making Unix and System 7 applications compliant with PowerOpen. A/UX 4.0 and AIX were intended to run on a variety of IBM's POWER and PowerPC hardware, and on Apple's PowerPC based hardware.

The need for the POE reduced due to the increasing availability of Unix-like operating systems on PowerPC, such as Linux distributions and AIX. The PowerOpen Association was formed to promote the POE and test for conformance, and disbanded in 1995. That year, other AIM elements disbanded.

Overview
The POE contains API and ABI specifications. The presence of the ABI specification in the POE distinguishes it from other open systems such as POSIX and XPG4, since it allows platform-independent binary compatibility, which is otherwise typically limited to particular hardware. Derived from AIX, the POE conforms to industry open standards including POSIX, XPG4, and Motif.

The POE is hardware bus independent. System implementations can range from laptop computers to supercomputers. It requires a multi-user, multitasking operating system. It provides networking support, an X Window System extension, a Macintosh Application Services extension, and Motif.

Macintosh Application Services (MAS) was an Apple software product intended to run existing Mac applications alongside other applications in the X environment, including those written for the 680x0 architecture. Also supporting Mac applications that had been ported to PowerPC, MAS was described as "Apple's key contribution to the PowerOpen alliance" and was demonstrated running Mac applications including a QuickTime movie on three different workstation platforms. It was an optional component in the PowerOpen architecture.

See also
 PowerPC Reference Platform

References 

 PowerOpen ABI specification
 This article was originally based on material from the Free On-line Dictionary of Computing and is used under the GFDL.

IBM software
Powdered sugar. Powdered sugar, also called confectioners' sugar and icing sugar is a finely ground sugar produced by milling granulated sugar into a powdered state. It usually contains between 2% and 5% of an anti-caking agent—such as corn starch, potato starch or tricalcium phosphate—to  absorb moisture, prevent clumping, and improve flow. Although most often produced in a factory, a proxy for powdered sugar can be made by processing ordinary granulated sugar in a coffee grinder, or by crushing it by hand in a mortar and pestle.

Use
Powdered sugar is used in industrial food production when a quick-dissolving sugar is required. Home cooks use it principally to make icing or frosting and other cake decorations. It is often dusted onto baked goods to add a subtle sweetness and delicate decoration.

Powdered sugar is available in varying degrees of fineness, most commonly XXX, XXXX, and 10X: the greater the number of Xs, the finer the particles. Finer particles absorb more moisture, which results in caking. Because of anticaking agents, it cannot always be used as a substitute for granulated sugar.  Canadian regulations limit powdered sugar to 5% starch or an anticaking agent.

Other varieties

Caster sugar
Caster sugar (also referred to as superfine, bar, or baker's sugar) has a larger particle size than powdered sugar, approximately half that of granulated sugar, and has no added starch. It is commonly used in baking and cold mixed drinks because it dissolves faster than granulated white sugar. Caster sugar can be easily prepared at home by grinding white sugar in a food processor to make it finer. The most common food caster sugar is used in is meringue.

Snow powder

Snow powder (or snow sugar) is a non-melting form of icing sugar used for visual appeal on cakes or pastries that require refrigeration. It usually contains glucose, starch, and anti-binding agents (such as titanium dioxide, which gives it a vibrant white color), and retains its structure and look even when dusted onto baked goods that are slightly wet, such as fruit bars and tarts. It will not melt even if it is sprinkled on whipped cream or ice cream. It is mostly used for decorative purposes.

Snow sugar is less sweet than regular powdered sugar because glucose is around 20% less sweet than table sugar, which also contains fructose. Fructose tastes more than twice as sweet as glucose.

History
Factory-made powdered sugar became available during the 19th century.  Before that, sugar came in the form of a sugar loaf, and bakers ground and sieved the lumps of sugar to get fine icing sugar.

References

Bibliography

 
 

Types of sugar
Food powders
Diacetylene. Diacetylene (also known as butadiyne) is the organic compound with the formula C4H2.  It is the simplest compound containing two triple bonds. It is first in the series of polyynes, which are of theoretical but not of practical interest.

Occurrence
Diacetylene has been identified in the atmosphere of Titan and in the protoplanetary nebula CRL 618 by its characteristic vibrational spectrum. It is proposed to arise by a reaction between acetylene and the ethynyl radical (C2H), which is produced when acetylene undergoes photolysis. This radical can in turn attack the triple bond in acetylene and react efficiently even at low temperatures.  Diacetylene has also been detected on the Moon.

Preparation
This compound may be made by the dehydrohalogenation of 1,4-dichloro-2-butyne by potassium hydroxide (in alcoholic medium) at ~70°C:

The bis(trimethylsilyl)-protected derivative may be prepared by the Hay coupling of (trimethylsilyl)acetylene:

See also
 Acetylene
 Diiodobutadiyne
 Butenyne
 Hydrocarbon

References

Further reading
 

Conjugated diynes
Auto-configuration. Auto-configuration is the automatic configuration of devices without manual intervention, without any need for software configuration programs or jumpers. Ideally, auto-configuring devices should just "plug and play".  Auto-configuration has been made common because of the low cost of microprocessors and other embedded controller devices. 

Configurations may be stored in NVRAM, loaded by a host processor, or negotiated at system initialization time. In some cases, hot pluggable devices may be able to renegotiate their configuration. 

Example of auto-configuring devices:
 USB

Example of auto-configuring devices and protocols:
 DHCP
 Zeroconf

See also
 Autoconfig, Amiga system for automatically setting up hardware peripherals
 FPGA
 Universal Plug and Play

Computer peripherals
Computer configuration