omniomni/omni-engineering huggingface dataset:
Reactive intermediate. In chemistry, a reactive intermediate or an intermediate is a short-lived, high-energy, highly reactive molecule. When generated in a chemical reaction, it will quickly convert into a more stable molecule. Only in exceptional cases can these compounds be isolated and stored, e.g. low temperatures, matrix isolation. When their existence is indicated, reactive intermediates can help explain how a chemical reaction takes place.

Most chemical reactions take more than one elementary step to complete, and a reactive intermediate is a high-energy, hence unstable, product that exists only in one of the intermediate steps. The series of steps together make a reaction mechanism.  A reactive intermediate differs from a reactant or product or a simple reaction intermediate only in that it cannot usually be isolated but is sometimes observable only through fast spectroscopic methods. It is stable in the sense that an elementary reaction forms the reactive intermediate and the elementary reaction in the next step is needed to destroy it.

When a reactive intermediate is not observable, its existence must be inferred through experimentation. This usually involves changing reaction conditions such as temperature or concentration and applying the techniques of chemical kinetics, chemical thermodynamics, or spectroscopy. Reactive intermediates based on carbon are radicals, carbenes, carbocations, carbanions, arynes, and carbynes.

Common features
Reactive intermediates have several features in common:
 low concentration with respect to reaction substrate and final reaction product
 with the exception of carbanions, these intermediates do not obey the lewis octet rule, hence the high reactivity
 often generated on chemical decomposition of a chemical compound
 it is often possible to prove the existence of this species  by spectroscopic means
 cage effects have to be taken into account
 often stabilisation by conjugation or resonance
 often difficult to distinguish from a transition state
 prove existence by means of chemical trapping

Carbon

Other reactive intermediates
Carbenoid
Ion-neutral complex
Keto anions
Nitrenes
Oxocarbenium ions
Phosphinidenes
Phosphoryl nitride
Tetrahedral intermediates in carbonyl addition reactions

See also 
 Activated complex
 Transition state

References

Extranol  links

 
Reaction mechanisms
Cage effect. In chemistry, the cage effect (also known as geminate recombination) describes how the properties of a molecule are affected by its surroundings. First introduced by James Franck and Eugene Rabinowitch in 1934, the cage effect suggests that instead of acting as an individual particle, molecules in solvent are more accurately described as an encapsulated particle. The encapsulated molecules or radicals are called cage pairs or geminate pairs. In order to interact with other molecules, the caged particle must diffuse from its solvent cage. The typical lifetime of a solvent cage is 10 seconds. Many manifestations of the cage effect exist.

In free radical polymerization, radicals formed from the decomposition of an initiator molecule are surrounded by a cage consisting of solvent and/or monomer molecules.  Within the cage, the free radicals undergo  many collisions leading to their recombination or mutual deactivation. This can be described by the following reaction:

After recombination, free radicals can either react with monomer molecules within the cage walls or diffuse out of the cage. In polymers, the probability of a free radical pair to escape recombination in the cage is 0.1 – 0.01 and 0.3-0.8 in liquids. In unimolecular chemistry, geminate recombination has first been studied in the solution phase using iodine molecules and heme proteins. In the solid state, geminate recombination has been demonstrated with small molecules trapped in noble gas solid matrices and in triiodide crystalline compounds.

Cage recombination efficiency 

The cage effect can be quantitatively described as the cage recombination efficiency  Fc where:

Here Fc is defined as the ratio of the rate constant for cage recombination (kc) to the sum of the rate constants for all cage processes. According to mathematical models, Fc is dependent on changes on several parameters including radical size, shape, and solvent viscosity. It is reported that the cage effect will increase with an increase in radical size and a decrease in radical mass.

Initiator efficiency 

In free radical polymerization, the rate of initiation is dependent on how effective the initiator is.  Low initiator efficiency, ƒ, is largely attributed to the cage effect. The rate of initiation is described as:

 

where Ri is the rate of initiation, kd is the rate constant for initiator dissociation,  [I] is the initial concentration of initiator. Initiator efficiency represents the fraction of primary radicals R·, that actually contribute to chain initiation. Due to the cage effect, free radicals can undergo mutual deactivation which produces stable products instead of initiating propagation – reducing the value of ƒ.

See also 
 Solvent effects
 Carrier generation and recombination
 Rate-determining step

References 

Chemistry theories
Theoretical chemistry
Reaction mechanisms
Spin transistor. The magnetically sensitive transistor, also known as the spin transistor, spin field-effect transistor (spinFET), Datta–Das spin transistor or spintronic transistor (named for spintronics, the technology which this development spawned), originally proposed in 1990 by Supriyo Datta and Biswajit Das, is an alternative design on the common transistor invented in the 1940s. This device was considered one of the Nature milestones in spin in 2008.

Description 

The spin transistor comes about as a result of research on the ability of electrons (and other fermions) to naturally exhibit one of two (and only two) states of spin: known as "spin up" and "spin down". Thus, spin transistors operate on electron spin as embodying a two-state quantum system. Unlike its namesake predecessor, which operates on an electric current, spin transistors operate on electrons on a more fundamental level; it is essentially the application of electrons set in particular states of spin to store information.

One advantage over regular transistors is that these spin states can be detected and altered without necessarily requiring the application of an electric current. This allows for detection hardware (such as hard drive heads) that are much smaller but even more sensitive than today's devices, which rely on noisy amplifiers to detect the minute charges used on today's data storage devices. The potential result is devices that can store more data in less space and consume less power, using less costly materials. The increased sensitivity of spin transistors is also being researched in creating more sensitive automotive sensors, a move being encouraged by a push for environmentally friendlier vehicles.

A second advantage of a spin transistor is that the spin of an electron is semi-permanent and can be used as means of creating cost-effective non-volatile solid state storage that does not require the constant application of current to sustain. It is one of the technologies being explored for magnetic random access memory (MRAM).

Because of its high potential for practical use in the computer world, spin transistors are currently being researched in various firms throughout the world, such as in England and in Sweden. Recent breakthroughs have allowed the production of spin transistors, using readily available substances, that can operate at room temperature: a precursor to commercial viability.

References

Transistor types
Spintronics
Jurmo-class landing craft. The Jurmo-class landing craft is a type of military transport in use by the Finnish Navy. The manufacturer Marine Alutech designates it as Watercat M12.

History
The Jurmo was the result of modernisation in the Finnish Navy in the late 1990s. It was designed to replace the existing Uisko class landing craft. Its main purpose is landing and transportation operations for the Finnish Coastal Jaegers in all weather conditions. It has good maneuverability and can come to a full stop in only one ship length from top speed. Low draft makes it suitable for amphibious assault even in shallow waters.

The Jurmo can transport 3 tons of cargo or 22 men.

The Jurmo is currently being evaluated by the German and Greek navies. Ten of the slightly larger and more powerful M14 version were delivered to the Royal Malaysian Police.

Operators 
 Finnish Navy: U601-U638. An additional 17 units were ordered on 2023-06-29

Royal Malaysian Police: 10 vessels of the Watercat M14 version.

Related development
G class landing craft
Uisko class landing craft
Watercat M14 class landing craft

References

External links

Finnish Defence Forces Website of The Finnish Defence Forces
Marine Alutech Website of Marine Alutech
 Watercat M12

Ships of the Finnish Navy
Ships built in Finland
Landing craft
Military boats
USS Katahdin (1893). USS Katahdin, a harbor-defense ram of innovative design, was the second ship of the United States Navy to be named for Mount Katahdin, a mountain peak in Maine.

Design and construction
The inspiration behind Katahdin was Rear Admiral Daniel Ammen, an advocate of a coastal defense navy. Ammen was impressed by the British torpedo ram HMS Polyphemus. Unlike Polyphemus, which was primarily a torpedo boat, with ramming a secondary function, the American design was for a pure ram, with no torpedoes carried.

Katahdins design was a new departure in naval architecture, built to ride extremely low in the water with her bow awash while under way. Her hull embodied several new features later used in early submarines. A similar design was the whaleback freighters of the Great Lakes which went into production in 1887.

An order was placed for construction of a prototype armored ram in 1889. Her keel was laid down by the Bath Iron Works of Bath, Maine in July 1891.  She was launched on 4 February, 1893, sponsored by Miss Una Soley, daughter of James R. Soley, the Assistant Secretary of the Navy, and commissioned at the New York Navy Yard on 20 February 1897.

Service history
Although Katahdins engines were more powerful than specified, Katahdin failed to reach the contracted speed of , requiring the passing of special legislation to allow her to be accepted by the Navy. Conditions aboard the ship were extremely uncomfortable, as it was cramped and had very poor ventilation, leading to almost intolerable temperatures being recorded.

Katahdin departed New York Harbor 4 March 1897, the day of President William McKinley's first inauguration, and sailed to Norfolk, Virginia, before decommissioning at Philadelphia Naval Yard on 17 April. A year later, with the Navy preparing for an impending war with Spain, she recommissioned there 10 March 1898. She was attached to the North Atlantic Squadron and operated along the Atlantic Coast from New England to Norfolk protecting the nation's seaboard cities from possible attack. After decisive American naval victories at Manila Bay and Santiago Harbor eliminated this threat, the ram decommissioned for the last time at Philadelphia Navy Yard on 8 October.

Katahdin was stricken from the Naval Vessel Register on 9 July 1909 and designated "Ballistic Experimental Target 'A'. Katahdin was sunk by gunfire at Rappahannock Spit, Virginia, that September.

See also
"Contract and Screw Trials of the U.S.S. Kathadin", Journal of the American Society of Naval Engineers, v.8, February, 1896, pages 1–20 (Full technical engineering details including drawings, description of contract issues)
USS Vesuvius

Citations

References

External links 
 

1893 ships
Rams of the United States Navy
Ships built in Bath, Maine
Ships sunk as targets
Shipwrecks of the Virginia coast
Shipwrecks in the Atlantic Ocean
Spanish–American War naval ships of the United States
Ships built by Bath Iron Works
Piaggio PD.808. The Piaggio PD.808 was an Italian business jet built by Piaggio. It was designed as a joint venture between Piaggio and Douglas Aircraft Company of Long Beach, California, United States.

Design and development
Originally named the PD.808 Vespa Jet the business jet was designed in a joint venture between Piaggio and the Douglas Aircraft Company. The basic design work was carried out by Douglas and the prototype was built at the Piaggio factory at Finale Ligure.

The PD.808 was a low-wing cantilever cabin-monoplane with tip-tanks and powered by two rear-mounted Bristol Siddeley Viper 525 turbojets. It has retractable tricycle landing gear and was originally designed with a cabin for a pilot and six-passengers.

The first Viper 525-powered prototype (with Italian Serial Number MM577) first flew on 29 August 1965, this was followed by a second Viper 525 powered prototype and two civil demonstrators.

The company tried to interest commercial operators (including offering a General Electric CJ610 variant) but the only interest was from the Italian Air Force as a liaison, training and radar calibration aircraft with an order for 25. The Italian Air Force aircraft were powered by Viper 526 turbojets.

Variants

PD-808VIP: VIP transport.
PD-808TA: navigation trainer.
PD-808RM (radiomisure): radio calibration, four-built
PD-808GE (guerra elettronica): aircraft modified for Electronic warfare, PD-808GE1 entered service in 1972, the PD-808GE2 in 1977.
PD-808TF: Proposed turbofan-powered version. Not built.

Operators

 Italian Air Force operated 22 Piaggio PD.808 from 1970 until 2003

Accidents and incidents
On 18 June 1968 one of the demonstration aircraft I-PIAI crashed in bad-weather when it flew into the side of Mount Jaizkibel, near San Sebastian, Spain, all six on-board including the Italian businessman Lino Zanussi and the Piaggio chief test pilot Davide Albertazzi were killed.

Aircraft on display

Italy
 MM62015 – PD-808GE on static display in Lucca, Tuscany. It was previously operated by the Italian Air Force.
 MM61961 - PD-808GE on static display outside the Museo Storico dell'Aeronautica Militare di Vigna di Valle (Italian Air Force Museum in Vigna di Valle), with "Ultimo Volo 17.5.03 (Final Flight 17-5-'03)" titles.

Specifications (PD.808)

References

Bibliography

PD.808
Douglas aircraft
1960s Italian business aircraft
1960s Italian military utility aircraft
Twinjets
Low-wing aircraft
Aircraft first flown in 1964
Cruciform tail aircraft
Aircraft with retractable tricycle landing gear
SGI Origin 350. The SGI Origin 350 is a mid-range server computer developed and manufactured by SGI introduced in 2003. Their discontinuation in December 2006 brought to a close almost two decades of MIPS and IRIX computing.

Hardware 

The Origin 350 is based on the NUMAflex architecture, where a system is constructed from a varying number of modules connected together using the NUMAlink3 interconnect via cables. A system can consist of 2 to 32 processors, 1 to 64 GB of memory and 4 to 62 PCI-X slots. For systems with more than 8 processors, a 2U NUMAlink module is required for routing. Modules for disk storage and further PCI slots were also available. Multiple modules are coordinated at power up by an L2 controller which communicated to the modules via USB ports. The L2 controller was an external PowerPC computer running Linux with console, USB, modem and Ethernet ports.

Compute module 

The 2U compute module contained the processors, memory and four PCI-X slots on two buses. Each compute module features an IP53 node board, which contains two or four MIPS R16000 microprocessors clocked at 600 or 700 MHz with 4 MB of ECC L2 cache, eight DIMM slots for 1 to 8 GB of ECC memory, a Bedrock ASIC serving as the crossbar for enabling communication between the processors, memory and PCI-X slots.

Two variants of the compute module exist, the base compute module and the system expansion compute modules. The difference between these two models is that the inclusion of a SCSI disk drive and an IO9 input/output card is mandatory in the base compute module, but optional in the system expansion compute module. The IO9 input/output card connects to a PCI-X slot and provides SCSI interfaces for two internal disks, an external SCSI port, audio I/O and a 10/100/1000BASE-T Ethernet connection.

References

 SGI Origin 350 Server System User's Guide, 007-4566-001, June 16, 2003, Silicon Graphics

External links 
 SGI: SGI Origin 350
 nekochan wiki: SGI Origin 350

Origin 350
GIS (disambiguation). GIS (Geographic information system)  is a computer-based system to analyse and present spatial data.

GIS or Gis may also refer to:

Business 
 General Mills, an American food manufacturer, NYSE symbol
 Madhya Pradesh Global Investors' Summit, Indore, India
 Green investment scheme
 Grey Island Systems International, a Canadian company
 Gunawan Iron and Steel, Indonesia

Government 
 Georgian Intelligence Service
 General Intelligence Directorate (Egypt)
 General Intelligence Service (Sudan)
 Ghana Immigration Service
 , Italian Carabinieri unit
 Government Information Services, Hong Kong 
 Guaranteed Income Supplement, to Canadian pension
 Integrated Security Unit (French: ), in Canada
 Special Intervention Group (French: ), of Algeria

Language 
 Giš, a cuneiform sign
 GIŠ (wood Sumerogram), a cuneiform determinative prefix for wooden items 
 North Giziga language

Places 
 Gis, Iran
 Greenland ice sheet

Schools 
 Garden International School, in Kuala Lumpur, Malaysia
 German International School Doha, in Qatar
 Gippsland Independent Schools, in Victoria, Australia
 Goshen Intermediate School, in New York, US
 Grace International School, in Chiang Mai, Thailand
 Granada Islamic School, in Santa Clara, California, US
 Greenoak International School, in Port Harcourt, Rivers State, Nigeria
 Global Indian School, in Ajman, United Arab Emirates

Science and technology 
 Gas imaging spectrometer, on Japan's Advanced Satellite for Cosmology and Astrophysics
 Gas-insulated switchgear
 Generalized iterative scaling
 Global information system

Other uses 
 Cemetery GIS, Giza Plateau, Egypt
 G♯ (musical note), German notation Gis
 Gadigal Information Service, which runs Koori Radio in Sydney, Australia
 Gateshead International Stadium, in Tyne and Wear, England
 Gisborne Airport, in New Zealand
 Gis Gelati, an Italian cycling team
 Partenope Napoli Basket, an Italian basketball team sponsored as Gis Napoli 1977–1978
 Guide International Service, of the UK Girl Guides Association

See also
 GI (disambiguation)
 Jizz (disambiguation)
Military Message Handling System. Military Message Handling System (MMHS) is a profile and set of extensions to X.400 for messaging in military environments. It is NATO standard STANAG 4406 and CCEB standard ACP 123. It adds to standard X.400 email support for military requirements such as mandatory access control (i.e. Classified/Secret/Top Secret messages and users, etc.).  In particular it defines a new message format, P772 that is used in place of X.400's interpersonal message formats P2 (1984 standard) and P22 (1988 standard). 

MMHS specifications are implemented by several X.400 vendors, particularly those located in Europe, such as Raytheon UK, Boldon James, Deep-Secure, Thales Group, Nexor, Cassidian and Isode.

Several RFC are supported:

Implementations

See also 
 Defense Message System
 Automated Message Handling System

References

Email
Connection-Oriented Network Service. Connection-Oriented Network Service (CONS) is one of the two Open Systems Interconnection (OSI) network-layer protocols, the other being Connectionless-mode Network Service (CLNS). It is basically X.25, with a few adjustments.

Protocols providing CONS
Some protocols that provide the CONS service:

 X.25, as specified in ITU-T Recommendation X.223 is a Public Data Network protocol that provides the Connection Oriented Network Service as described in ITU-T Recommendation X.213.
 Signalling Connection Control Part (SCCP), as specified in ITU-T Recommendation Q.711 is a Signaling System 7 protocol that provides the Connection Oriented Network Service as described in ITU-T Recommendation X.213.
 Service Specific Connection Oriented Protocol (SSCOP), as specified in ITU-T Recommendation Q.2110 is an Asynchronous Transfer Mode protocol that provides the Connection Oriented Network Service as described in ITU-T Recommendation X.213.

OSI protocols
Network layer protocols
Business object. A business object is an entity within a multi-tiered software application that works in conjunction with the data access and business logic layers to transport data.

Business objects separate state from behaviour because they are communicated across the tiers in a multi-tiered system, while the real work of the application is done in the business tier and does not move across the tiers.

Function
Whereas a program may implement classes, which typically end in objects managing or executing behaviours, a business object usually does nothing itself but holds a set of instance variables or properties, also known as attributes, and associations with other business objects, weaving a map of objects representing the business relationships.

A domain model where business objects do not have behaviour is called an anemic domain model.

Examples 
For example, a "Manager" would be a business object where its attributes can be "Name", "Second name", "Age", "Area", "Country" and it could hold a 1-n association with its employees (a collection of "Employee" instances).

Another example would be a concept like "Process" having "Identifier", "Name", "Start date", "End date" and "Kind" attributes and holding an association with the "Employee" (the responsible) that started it.

See also
Active record pattern, design pattern that stores object data in memory in relational databases, with functions to insert, update, and delete records
Business intelligence, a field within information technology that provides decision support and business-critical information based on data
Data access object, design pattern that provides an interface to a type of database or other persistent mechanism, and offers data operations to application calls without exposing database details
Data transfer object, design pattern where an object carries aggregated data between processes to reduce the number of calls

References

Rockford Lhotka, Visual Basic 6.0 Business Objects, 
Rockford Lhotka, Expert C# Business Objects, 
Rockford Lhotka, Expert One-on-One Visual Basic .NET Business Objects,

External links
A definition of domain model by Martin Fowler
Anemic Domain Model by Martin Fowler

Programming constructs