omniomni/omni-engineering huggingface dataset:
Pyrene. Pyrene is a polycyclic aromatic hydrocarbon (PAH) consisting of four fused benzene rings, resulting in a flat aromatic system.  The chemical formula is .  This yellow-green solid is the smallest peri-fused PAH (one where the rings are fused through more than one face).  Pyrene forms during incomplete combustion of organic compounds.

Occurrence and properties
Pyrene was first isolated from coal tar, where it occurs up to 2% by weight.  As a peri-fused PAH, pyrene is much more resonance-stabilized than its five-member-ring containing isomer fluoranthene.  Therefore, it is produced in a wide range of combustion conditions.  For example, automobiles produce about 1 μg/km.

Reactions
Oxidation with chromate affords perinaphthenone and then naphthalene-1,4,5,8-tetracarboxylic acid. Pyrene undergoes a series of hydrogenation reactions and is susceptible to halogenation, Diels-Alder additions, and nitration, all with varying degrees of selectivity.  Bromination occurs at one of the 3-positions.

Reduction with sodium affords the radical anion. From this anion, a variety of pi-arene complexes can be prepared.

Photophysics

Pyrene and its derivatives are used commercially to make dyes and dye precursors, for example pyranine and naphthalene-1,4,5,8-tetracarboxylic acid. It has strong absorbance in UV-Vis  in three sharp bands at 330 nm in DCM. The emission is close to the absorption, but moving at 375 nm.  The morphology of the signals change with the solvent. Its derivatives are also valuable molecular probes via fluorescence spectroscopy, having a high quantum yield and lifetime (0.65 and 410 nanoseconds, respectively, in ethanol at 293 K).  Pyrene was the first molecule for which excimer behavior was discovered. Such excimer appears around 450 nm.  Theodor Förster reported this in 1954.

Applications

Pyrene's fluorescence emission spectrum is very sensitive to solvent polarity, so pyrene has been used as a probe to determine solvent environments. This is due to its excited state having a different, non-planar structure than the ground state. Certain emission bands are unaffected, but others vary in intensity due to the strength of interaction with a solvent.

Pyrenes are strong electron donor materials and can be combined with several materials in order to make electron donor-acceptor systems which can be used in energy conversion and light harvesting applications.

Safety and environmental factors
Although it is not as problematic as benzopyrene, animal studies have shown pyrene is toxic to the kidneys and liver. It is now known that pyrene affects several living functions in fish and algae.

Its biodegradation has been heavily examined.  The process commences with dihydroxylation at each of two kinds of CH=CH linkages. Experiments in pigs show that urinary 1-hydroxypyrene is a metabolite of pyrene, when given orally.

See also
 List of interstellar and circumstellar molecules
 Perhydropyrene

References

Cited sources

Further reading
 
 
 
 

Pyrenes
Polycyclic aromatic hydrocarbons
PBT substances
ALCO Century 630. The ALCO Century 630 is a model of six-axle,  diesel-electric locomotive built by the American Locomotive Company (ALCO) between 1965 and 1967.  It used the ALCO 251 prime mover.  77 were built: 3 for Atlantic Coast Line Railroad, 4 for Chesapeake and Ohio Railway, 8 for Louisville and Nashville Railroad, 10 (with high noses) for Norfolk and Western Railway, 15 for Pennsylvania Railroad, 12 for the Reading Company, 15 for Southern Pacific Railroad and 10 for Union Pacific Railroad.

Montreal Locomotive Works produced a C630M variant of the C630, with 4 for British Columbia Railway, 8 for Canadian Pacific Railway and 44 for Canadian National. MLW M-630s were built by Montreal Locomotive Works from 1969 to 1973: 29 for CPR, 26 for BCR, and 20 for Ferrocarriles Nacional de Mexico (N de M). Eight of the BCR locomotives were designated M630(W) and were built with a wide-nosed cab, known as the "Canadian" or "safety" cab.  The latter two models, along with the nearly identical MLW M-636, had more in common with the ALCO C636 than the C630, and all MLW versions rode on high-adhesion trucks cast by Dofasco.

In January 1975, four Chesapeake and Ohio Railway locomotives were sold to Robe River Iron Associates in the Pilbara region of Western Australia. One was destroyed in an accident in February 1979, with the remaining three rebuilt by A Goninan & Co, Perth as CM40-8s in the early 1990s.

C630s are still in service with the Western New York & Pennsylvania Railroad, Delaware-Lackawanna Railroad and other short line railroads.

Preservation 
Norfolk and Western #1135 is preserved at the Virginia Museum of Transportation in Roanoke, Virginia.
Reading #5308 is preserved at the Reading Railroad Heritage Museum in Hamburg, Pennsylvania
Union Pacific #2907 is preserved at the Arkansas Railroad Museum in Pine Bluff, Arkansas. 
Canadian Pacific #4563 is preserved at the Canadian Railway Museum (Exporail) in Quebec, Canada.

See also
List of ALCO diesel locomotives
List of MLW diesel locomotives

References

External links
Sarberenyi, Robert. Alco C630 Original Owners.
American-Rails.com profile of the Alco C630.

Century 630
C-C locomotives
Diesel–electric locomotives of the United States
Diesel locomotives of Western Australia
Century 630
Railway locomotives introduced in 1965
Standard gauge locomotives of Canada
Standard gauge locomotives of the United States
Standard gauge locomotives of Mexico
Diesel–electric locomotives of Australia
Diesel–electric locomotives of Canada
Diesel–electric locomotives of Mexico
ALCO Century 628. The ALCO Century 628 was a six-axle,  diesel-electric locomotive. A total of 186 C628s were built between December 1963 and December 1968. There were 135 C628s built for US railroads, 46 C628s built for Mexican railroads, and five C628s for Australia.

The C628 replaced the C624 (DL600C/RSD-41) as a part of ALCO's 'Century' line of locomotives. The C624 was intended to replace the earlier RSD-15 model, but was never built. The C628 was offered instead in August 1963.

Hamersley Iron purchased five to haul iron ore services in the Pilbara region of Western Australia. Two were built in Schenectady and three by AE Goodwin in Sydney. All had been retired by 1982, with one preserved on a plinth in Dampier.

The Southern Pacific purchased the four demonstrators in 1964, and an additional 25 C628s were delivered in 1965.

Preserved

Australia
 No. 2000 preserved by the Pilbara Railways Historical Society

North America
 Nacionales de Mexico 610, formerly Delaware and Hudson 610, preserved at the Yucatán Railway Museum in Mexico
 Ferrocarriles Nacionales de Mexico 606, formerly Ferrocarril de Pacifico 606, preserved at the Yucatán Railway museum in Mexico

References

Alco Century 628 Study by Win Cuisnier (Preston Cook) Extra 2200 South Issue #54 Oct-Dec 1975 p. 21.   
Alco Century (and predecessors) Spec-Profile by Don Dover Extra 2200 South Issue #54 Oct-Dec 1975 p. 22

External links

Sarberenyi, Robert. Alco C628 Original Owners.

Century 628
C-C locomotives
Diesel–electric locomotives of the United States
Diesel locomotives of Western Australia
Railway locomotives introduced in 1963
Standard gauge locomotives of Australia
Standard gauge locomotives of Mexico
Standard gauge locomotives of the United States
Diesel–electric locomotives of Australia
Diesel–electric locomotives of Mexico
Sackur–Tetrode equation. The Sackur–Tetrode equation is an expression for the entropy of a monatomic ideal gas.

It is named for Hugo Martin Tetrode (1895–1931) and Otto Sackur (1880–1914), who developed it independently as a solution of Boltzmann's gas statistics and entropy equations, at about the same time in 1912.

Formula
The Sackur–Tetrode equation expresses the entropy  of a monatomic ideal gas in terms of its thermodynamic state—specifically, its volume , internal energy , and the number of particles :

where  is the Boltzmann constant,  is the mass of a gas particle and  is the Planck constant.

The equation can also be expressed in terms of the thermal wavelength :

For a derivation of the Sackur–Tetrode equation, see the Gibbs paradox. For the constraints placed upon the entropy of an ideal gas by thermodynamics alone, see the ideal gas article.

The above expressions assume that the gas is in the classical regime and is described by Maxwell–Boltzmann statistics (with "correct Boltzmann counting"). From the definition of the thermal wavelength, this means the Sackur–Tetrode equation is valid only when

The entropy predicted by the Sackur–Tetrode equation approaches negative infinity as the temperature approaches zero.

Sackur–Tetrode constant
The Sackur–Tetrode constant, written S0/R, is equal to S/kBN evaluated at a temperature of T = 1 kelvin, at standard pressure (100 kPa or 101.325 kPa, to be specified), for one mole of an ideal gas composed of particles of mass equal to the atomic mass constant ().  Its 2018 CODATA recommended value is:
S0/R =  for po = 100 kPa
S0/R =  for po = 101.325 kPa.

Information-theoretic interpretation 

In addition to the thermodynamic perspective of entropy, the tools of information theory can be used to provide an information perspective of entropy. In particular, it is possible to derive the Sackur–Tetrode equation in information-theoretic terms. The overall entropy is represented as the sum of four individual entropies, i.e., four distinct sources of missing information. These are positional uncertainty, momenta uncertainty, the quantum mechanical uncertainty principle, and the indistinguishability of the particles. Summing the four pieces, the Sackur–Tetrode equation is then given as

The derivation uses Stirling's approximation, . Strictly speaking, the use of dimensioned arguments to the logarithms is incorrect, however their use is a "shortcut" made for simplicity. If each logarithmic argument were divided by an unspecified standard value expressed in terms of an unspecified standard mass, length and time, these standard values would cancel in the final result, yielding the same conclusion. The individual entropy terms will not be absolute, but will rather depend upon the standards chosen, and will differ with different standards by an additive constant.

References

Further reading
 .
 . (This derives a Sackur–Tetrode equation in a different way, also based on information.)
 .
 .

Equations of state
Ideal gas
Thermodynamic entropy
Logical clock. A logical clock is a mechanism for capturing chronological and causal relationships in a distributed system. Often, distributed systems may have no physically synchronous global clock. In many applications (such as distributed GNU make), if two processes never interact, the lack of synchronization is unobservable and in these applications it is enough for the processes to agree on the event ordering (i.e., logical clock) rather than the wall-clock time. The first logical clock implementation, the Lamport timestamps, was proposed by Leslie Lamport in 1978 (Turing Award in 2013).

Local vs global time
In logical clock systems each process has two data structures: logical local time and logical global time. Logical local time is used by the process to mark its own events, and logical global time is the local information about global time. A special protocol is used to update logical local time after each local event, and logical global time when processes exchange data.

Applications
Logical clocks are useful in computation analysis, distributed algorithm design, individual event tracking, and exploring computational progress.

Algorithms
Some noteworthy logical clock algorithms are:

 Lamport timestamps, which are monotonically increasing software counters.
 Vector clocks, that allow for partial ordering of events in a distributed system.
 Version vectors, order replicas, according to updates, in an optimistic replicated system.
 Matrix clocks, an extension of vector clocks that also contains information about other processes' views of the system.

References

External links
 Distributed System Logical Time // Roberto Baldoni, Silvia Bonomi. MIDLAB, Sapienza University of Rome
 Chapter 3: Logical Time // Ajay Kshemkalyani and Mukesh Singhal, Distributed Computing: Principles, Algorithms, and Systems, Cambridge University Press, 2008
 Distributed Systems 06. Logical Clocks // Paul Krzyzanowski, Rutgers University, Fall 2014

Causality
Distributed algorithms
Multi-Vendor Integration Protocol. The Multi-Vendor Integration Protocol (MVIP) is a hardware bus for computer telephony integration (Audiotex) equipment, a PCM data highway for interconnecting expansion boards inside a PC. It was invented and brought to market by Natural Microsystems Inc (now BPQ Communicationser).

The MVIP (Multi-Vendor Integration Protocol) is a technology used in the construction of call center equipment utilizing standard PCs. It provides a secondary communications bus within the computer, capable of multiplexing up to 256 full-duplex voice channels, which enables the transfer of voice data between different voice cards. Digital voice, fax, and video data are transmitted over a ribbon cable connected at the top of each ISA or PCI card. MVIP technology allows a PC to function similarly to a small-scale private branch exchange (PBX) system. The protocol accommodated for a variety of expansion boards, including trunk interfaces (usually T1 or ISDN), voice processing boards equipment  speech recognition or fax processing. Each board could optionally provide a switch that could interconnect voice channels on the bus, allowing for a flexible routing of calls within the MVIP bus.

The MVIP bus was promoted as an alternative to the then-dominant PEB bus by Dialogic Corporation which had much less capacity and was not an open standard.

References

External links
http://www.mvip.org/ 
http://www.mvip.org/Overview.htm 

Computer buses
Computer telephony integration
MSE. MSE may refer to:

Education
 Master of Science in Engineering, a university degree
 Master of Science in Software Engineering, a college degree in software engineering
 Master of Software Engineering, a university degree; for example at the Information and Communications University

Science, technology and engineering
 Manned Spaceflight Engineer, an astronaut in the United States Air Force's Manned Spaceflight Engineer Program
 Mars Surface Exploration
 Materials Science and Engineering
 Maunakea Spectroscopic Explorer, a planned renovation of the Canada–France–Hawaii Telescope
 Maximum spacing estimation, in statistics
 Mean squared error, in statistics
 Mechanically stabilized earth
 Mental status examination, used by clinicians to assess aspects of a patient's mental state
 Mercury Surface Element, the lander portion of BepiColombo space mission
 MSE (centrifuges), Measuring and Scientific Equipment, manufacturer of laboratory centrifuges
 Selenomethionine, a naturally occurring amino acid

Computing
 Message Stream Encryption, a BitTorrent protocol encryption
 Media Source Extensions, a W3C standard for Javascript media streaming
 Metasearch engine, a search engine that consolidates results from other search engines
 Microsoft Security Essentials, a free antivirus software
 Mobile Subscriber Equipment, a tactical communications system formerly used by units such as the 17th Signal Battalion (United States)

Stock exchanges
 Macedonian Stock Exchange
 Madras Stock Exchange
 Madrid Stock Exchange
 Malawi Stock Exchange
 Malta Stock Exchange
 Mongolian Stock Exchange
 Montenegro Stock Exchange
 Montreal Stock Exchange

Other
 Kent International Airport, by IATA airport code
 Mississippi Export Railroad, common freight carrier in Mississippi, by reporting mark
 Martha Stewart Everyday, a mass-market brand of Martha Stewart Living Omnimedia sold through Kmart
 Medical Science Educator, academic journal
 Melbourne String Ensemble
 Micro and Small Enterprises
 Ministry of Sustainability and the Environment, in Singapore
 MoneySavingExpert.com, a British consumer finance information website
 Monumental Sports & Entertainment, American sports and venue management company
Vacuum oven. In chemistry, a vacuum oven is an oven that can also apply a vacuum to its contents.  Such devices are useful for removing solvent or dehydrating samples.  They are equivalent to Abderhalden's drying pistol in some ways, but vacuum ovens typically can accommodate large samples.  A characteristic operation for a vacuum oven is the activation or regeneration of molecular sieves.  Vacuum furnaces are related devices that operate at much higher temperatures and much lower pressures.

The acetylacetonate complex Mn(acac)2 is obtained by vacuum drying the yellow dihydrate Mn(acac)2(H2O)2.

References

Laboratory equipment
Ovens
International Psychopharmacology Algorithm Project. The International Psychopharmacology Algorithm Project (IPAP) is a non-profit corporation whose purpose is to "enable, enhance, and propagate" use of algorithms for the treatment of some Axis I psychiatric disorders.

Kenneth O Jobson founded the Project. The Dean Foundation provides funding.

IPAP has organized and supported several international conferences on psychopharmacology algorithms. It has also supported the creation of several algorithms based on expert opinion. It is now in the process of creating "evidence-based algorithms," that is algorithms created by experts and annotated with the evidence that leads to these algorithms. A schizophrenia algorithm has been created and one on Post Traumatic Stress Disorder (PTSD) was released in July 2005. A general anxiety disorder (GAD) algorithm was released in 2006. Periodic updates of the algorithms are released as the basis of evidence changes. In addition, the algorithms are being translated into various non-English languages (Chinese, Japanese, Spanish, and Thai) as the availability of translators permits.

References

External links
 

Psychiatry organizations
Biostatistics
USCGC Sundew. USCGC Sundew (WLB-404) was a  sea going buoy tender (WLB). An Iris, or C-class tender, it was built by Marine Iron and Shipbuilding Corporation in Duluth, Minnesota, United States.  Sundews preliminary design was completed by the United States Lighthouse Service and the final design was produced by Marine Iron and Shipbuilding Corporation in Duluth for the U.S. Coast Guard. On 29 November 1943 the keel was laid. It was launched on 8 February 1944 and commissioned on 24 August 1944. The original cost for the hull and machinery was $861,589.

Sundew is one of 39 original  seagoing buoy tenders built between 1942-1944. All but one of the original tenders, , were built in Duluth. Like all of these tenders, Sundew was named after a plant, in this case the sundew, a carnivorous plant from the genus Drosera.

In 1958, Sundew was assigned to Charlevoix, Michigan, and the following November helped in the rescue of two survivors from the Carl D. Bradley when it sank in a storm on Lake Michigan  west-northwest of Charlevoix. Sundew remained at Charlevoix until 1981, when she was replaced by .  Sundew was then moved to Duluth, Minnesota, where it served until it was retired in 2004.

Sundew served 60 years for the Coast Guard and was decommissioned and retired on 27 May 2004. As part of the decommissioning, the vessel was given to the city of Duluth, its last home port, to be used as a museum ship. The services provided by the Sundew were taken up by .

Due to a drop in tourism revenue, in 2009 the city of Duluth sold Sundew to local residents, Jeff and Toni Foster, David Johnson and Mary Phillipp. The Sundew moved from its museum location in Duluth in the spring of 2010, and currently (2024) occupies a private slip near Duluth's Great Lakes Aquarium.

External links 
Sundew - U.S. Coast Guard Cutter, WLB 404
National Park Service Report on the  buoy tenders
Photo history of USCG buoy tenders by the Coast Guard Historian's Office
Article Winter 2004 Article from North Star Port Magazine

Iris-class seagoing buoy tenders
1944 ships
Historic American Engineering Record in Minnesota
Museum ships in Minnesota
Ships built in Duluth, Minnesota
Cache coloring. In computer science, cache coloring (also known as page coloring) is the process of attempting to allocate free pages that are contiguous from the CPU cache's point of view, in order to maximize the total number of pages cached by the processor. Cache coloring is typically employed by low-level dynamic memory allocation code in the operating system, when mapping virtual memory to physical memory. A virtual memory subsystem that lacks cache coloring is less deterministic with regards to cache performance, as differences in page allocation from one program run to the next can lead to large differences in program performance.

Details of operations

A physically indexed CPU cache is designed such that addresses in adjacent physical memory blocks take different positions ("cache lines") in the cache, but this is not the case when it comes to virtual memory; when virtually adjacent but not physically adjacent memory blocks are allocated, they could potentially both take the same position in the cache. Coloring is a technique implemented in memory management software, which solves this problem by selecting pages that do not contend with neighbor pages.

Physical memory pages are "colored" so that pages with different "colors" have different positions in CPU cache memory. When allocating sequential pages in virtual memory for processes, the kernel collects pages with different "colors" and maps them to the virtual memory. In this way, sequential pages in virtual memory do not contend for the same cache line.

Implementations
This code adds a significant amount of complexity to the virtual memory allocation subsystem, but the result is well worth the effort. Page coloring makes virtual memory as deterministic as physical memory with regard to cache performance. Page coloring is employed in operating systems such as Solaris, FreeBSD, NetBSD, and Windows NT.

References

External links 

"Page Placement Algorithms for Large Real-Indexed Caches," by  R. E. Kessler, Mark D. Hill, University of Wisconsin, 1992.
"Colorable Memory," by Jochen Liedtke, IBM T. J. Watson Center, Nov. 1996.
"缓存着色技术," by  Maray, CSDN Technological Blog, 2008.

Cache (computing)
GWR Banking Class. The Banking Class were five  Brunel gauge steam locomotives for assisting ("banking") trains up inclines on the Great Western Railway. Designed by Daniel Gooch, they were tank engine versions of his Standard Goods class, and mainly built at Swindon Works.

The last one was withdrawn in 1889.

Locomotives
Avalanche (1846–1865)
Built in February 1846 and ceasing work in August 1865, Avalanche was not part of the Swindon-built Standard Goods locomotive build, but instead it was built by the Stothert and Slaughter and was similar to the Caesar class tender goods engines.
Bithon (1854–1871)
Iago (1852–1881)
Juno (1852–1889)
Juno was sold to the South Devon Railway in June 1872, where it was renamed Stromboli. It returned to the GWR upon absorption of the SDR in 1876, when it was given the number 2138 but retained its Stromboli name. It was the last survivor, being withdrawn in June 1889.
Plato (1854–1883)

References

Banking
0-6-0ST locomotives
Broad gauge (7 feet) railway locomotives
Avonside locomotives
Railway locomotives introduced in 1846
Railway locomotives introduced in 1852
South Devon Railway locomotives
Scrapped locomotives