omniomni/omni-engineering huggingface dataset:
Perrhenic acid. Perrhenic acid is the chemical compound with the formula . It is obtained by evaporating aqueous solutions of . Conventionally, perrhenic acid is considered to have the formula , and a species of this formula forms when rhenium(VII) oxide sublimes in the presence of water or steam. When a solution of  is kept for a period of months, it breaks down and crystals of  are formed, which contain tetrahedral . For most purposes, perrhenic acid and rhenium(VII) oxide are used interchangeably. Rhenium can be dissolved in nitric or concentrated sulfuric acid to produce perrhenic acid.

Properties
The structure of solid perrhenic acid is . This species is a rare example of a metal oxide coordinated to water; most often metal–oxo–aquo species are unstable with respect to their corresponding hydroxides:

The two rhenium atoms have different bonding geometries, with one being tetrahedral and the other octahedral, and with the water ligands coordinated to the latter.

Gaseous perrhenic acid is tetrahedral, as suggested by its formula .

Reactions
Perrhenic acid or the related anhydrous oxide  converts to dirhenium heptasulfide upon treatment with hydrogen sulfide:

The heptasulfide catalyzes various reductions.

Perrhenic acid in the presence of hydrochloric acid undergoes reduction in the presence of thioethers and tertiary phosphines to give rhenium(V) complexes with the formula .

Perrhenic acid combined with platinum on a support gives rise to a useful hydrogenation and hydrocracking catalyst for the petroleum industry. For example, silica impregnated with a solution of perrhenic acid is reduced with hydrogen at 500 °C. This catalyst is used in the dehydrogenation of alcohols and also promotes the decomposition of ammonia.

Catalysis
Perrhenic acid is a precursor to a variety of homogeneous catalysts, some of which are promising in niche applications that can justify the high cost of rhenium. In combination with tertiary arsines, perrhenic acid gives a catalyst for the epoxidation of alkenes with hydrogen peroxide. Perrhenic acid catalyses the dehydration of oximes to nitriles.

Other uses
Perrhenic acid is also used in the manufacture of x-ray targets.

See also
Perrhenate
Rhenium(VII) oxide

References

Mineral acids
Perrhenates
Transition metal oxoacids
Möve 101. The Möve 101 was a microcar with egg-shaped coupé bodywork based on a Felber Autoroller chassis. Ten cars were built in Vienna by a specialist coachbuilding company Hofmann & Moldrich in 1953. Though the fully enclosed bodywork made from 0.8 mm aluminium plate was more sophisticated than that of the Felber, the car proved more expensive to produce and the heavier bodywork reduced performance and made the car less stable. Möve translates into English as Gull. The only known survivor is in the Automobilmuseum Aspang/Wechsel in Austria.

See also 
List of microcars by country of origin

References

Microcars
Cars of Austria
Cars introduced in 1953
Homilite. Homilite is a borosilicate mineral belonging to the gadolinite group of minerals with formula .

It occurs as brown monoclinic crystals (space group P21/a) within feldspar masses in pegmatite and was discovered in 1876 in Stoko island, Langesundfiord, Norway. The name is from the Greek for to occur together, in allusion to its association with meliphanite and
allanite.

References

Calcium minerals
Iron(II) minerals
Magnesium minerals
Borate minerals
Nesosilicates
Monoclinic minerals
Minerals in space group 14
Borosilicates
Hopeite. Hopeite is a hydrated zinc phosphate with formula: Zn3(PO4)2·4H2O. It is a rare mineral used mainly as a collectors specimen.

Hopeite crystallizes in the orthorhombic system with prismatic, vitreous white to yellow crystals. It also forms druzy encrustations and reniform (kidney-shaped) masses. The related mineral parahopeite, which has the same composition but different crystal structure, is triclinic. The minerals are formed through oxidation of sphalerite by the presence of phosphate-rich solutions.

It was first described in 1822 from Moresnet, Liège Province, Belgium and is named after Scottish chemist, Thomas Charles Hope (1766–1844) of the University of Edinburgh.

It has been found in Zambia associated with lazulite.

Hopeite is one of the two conversion minerals arising from the application of the rust converter 'Fertan'.

References

 Mindat with location data
 Mineral galleries
 Webmineral data

Phosphate minerals
Zinc minerals
Tetrahydrate minerals
Orthorhombic minerals
Minerals in space group 62
Minerals described in 1822
LNER Class J94. The London and North Eastern Railway (LNER) J94 Class is a class of steam locomotive that was formed when 75 former "Austerity" 0-6-0STs were purchased by the LNER in 1946 from the War Department.


Overview 
The LNER had trials with one in November 1945 and bought 75 of them in 1946, numbering them 8006-80.  All entered British Railways (BR) service in 1948.  BR added 60000 to their numbers so they became 68006-80, and classified them 4F.

They were used for shunting in docks, and other similar work where their short wheelbase meant they could negotiate sharp curves.  They were used on the Cromford and High Peak Railway in Derbyshire, where they displaced the ex-North London Railway Class 75 class 2F s.

They were withdrawn between 1959 and 1967.  A few were sold into industrial use with the National Coal Board (who had several other Austerities) and others.

Stock list

Preservation 

Two, BR Nos 68077 and 68078 and have been preserved. In addition a large number of Austerities that were used in industry and have survived to preservation.  Several of these have been disguised as BR locomotives. . Enthusiasts often refer to them by the nickname of "Buckets".

LNER/BR J94s

Locomotives disguised as J94s

Models 
The erstwhile Rosebud Kitmaster company produced an unpowered polystyrene injection moulded model kit for 00 gauge, which went on sale in Spring 1961. In early 1963, the Kitmaster brand was sold by its parent company (Rosebud Dolls) to Airfix, who transferred the moulding tools to their own factory; they re-introduced some of the former Kitmaster range, including this locomotive. The tool (for this model) was destroyed in a fire at the premises of Dapol Model Railways Ltd in Winsford, Cheshire so that Dapol were unable to produce further kits after their first two production runs totalling 4000 kits after acquisition of the former Airfix moulds.

References 

 
  (Introduction by Don Townsley)

External links 

 The Riddles J94 (WD Austerity) 0-6-0ST Locomotives LNER Encyclopedia
 Class J94 Details at Rail UK

J94
0-6-0ST locomotives
Railway locomotives introduced in 1946
Standard gauge steam locomotives of Great Britain
Shunting locomotives
Attribute-oriented programming. Attribute-oriented programming (@OP) is a technique for embedding metadata, namely attributes, within program code.

Attribute-oriented programming in various languages

Java 
With the inclusion of Metadata Facility for Java (JSR-175) into the J2SE 5.0 release it is possible to utilize attribute-oriented programming right out of the box.
XDoclet library makes it possible to use attribute-oriented programming approach in earlier versions of Java.

C# 
The C# language has supported attributes from its very first release. These attributes was used to give run-time information and are not used by a preprocessor. Currently with source generators, you can use attributes to drive generation of additional code at compile-time.

UML 
The Unified Modeling Language (UML) supports a kind of attribute called stereotypes.

Hack 
The Hack programming language supports attributes. Attributes can be attached to various program entities, and information about those attributes can be retrieved at run-time via reflection.

Tools 
 Annotation Processing Tool (apt)
 Spoon, an Annotation-Driven Java Program Transformer
 XDoclet, a Javadoc-Driven Program Generator

References

External links
 Don Schwarz. Peeking Inside the Box: Attribute-Oriented Programming with Java5
 Sun JSR 175
 Attributes and Reflection - sample chapter from Programming C# book
 Modeling Turnpike Project
 Fraclet : An annotation-based programming model for the Fractal component model
 Attribute Enabled Software Development book

Programming paradigms
Transport corridor. A transport corridor is a generally linear area that is defined by one or more modes of transportation crossing the limits of more than one city or county like highways, railroads or public transit which share a common destination. Development often occurs around transportation corridors because they carry so many people, creating linear agglomerations like the Las Vegas Strip or the linear form of many neighborhood retail areas.

A 2019 review and meta-analysis of research into transport corridors found that they improved economic welfare, but had adverse environmental impacts.

Examples
 TEN-T Core Network Corridors – planned infrastructure network in the European Union
 Transportation Corridor Agencies – administrative body for toll roads in Orange County, California.
 Pan-European corridors – planned intercity rail network in Central and Eastern Europe
 Western Railway Corridor – proposed rail network in western Ireland
 Southeast High Speed Rail Corridor – proposed high-speed rail network in the Mid-Atlantic and Southeastern United States
 Northeast Corridor – Amtrak high-speed rail network in the Northeast megalopolis of the United States
 Panama Canal – artificial waterway linking the Atlantic Ocean and the Pacific Ocean

SE Asia
Sourced from 
 North–South Economic Corridor
 East–West Economic Corridor
 Southern Economic Corridor

See also
 Ribbon development
 Linear settlement
 Right-of-way (transportation)
 economic corridor

References

Rail infrastructure
Road infrastructure
 
Urban studies and planning terminology
System of record. A system of record (SOR) or source system of record (SSoR) is a data management term for an information storage system (commonly implemented on a computer system running a database management system) that is the authoritative data source for a given data element or piece of information, like for example a row (or record) in a table. In data vault it is referred to as the record source.

Background 
The need to identify systems of record can become acute in organizations where management information systems have been built by taking output data from multiple source systems, re-processing this data, and then re-presenting the result for a new business use.

In these cases, multiple information systems may disagree about the same piece of information. These disagreements may stem from semantic differences, differences in opinion, use of different sources, differences in the timing of the extract, transform, load processes that create the data they report against, or may simply be the result of bugs.

Use 
The integrity and validity of any data set is open to question when there is no traceable connection to a good source, and listing a source system of record is a solution to this. Where the integrity of the data is vital, if there is an agreed system of record, the data element must either be linked to, or extracted directly from it. In other cases, the provenance and estimated data quality should be documented. 

The "system of record" approach is a good fit for environments where both:
 there is a single authority over all data consumers, and 
 all consumers have similar needs

Trade-offs  
In diverse environments, one instead needs to support the presence of multiple opinions. Consumers may accept different authorities or may differ on what constitutes an authoritative source -- researchers may prefer carefully vetted data, while tactical military systems may require the most recent credible report.

See also
 Golden record (informatics), the master version or valid version of a data element in a single source of truth system
 Master data management, defining the handling of master data
 Privacy Act of 1974, U.S. law including requirement for agencies to publish System Of Records Notices (SORN) in the Federal Register to identify the system and describe the use of individuals' data.
 Single source of truth, practice of using one source for a particular data element

References

Nwaneri, Chineye (2019-02-12).  "System of Record, System of Reference, Golden Records, and other confusing terms in Master Data Management".  Retrieved 2020-06-06.

Information systems
Data management
LAND. A LAND (local area network denial) is a denial-of-service attack that consists of sending a special poison spoofed packet to a computer, causing it to lock up. The security flaw was first discovered in 1997 by someone using the alias and has resurfaced many years later in operating systems such as Windows Server 2003 and Windows XP SP2.

Mechanism 
The attack involves sending a spoofed TCP SYN packet (connection initiation) with the target host's IP address to an open port as both source and destination. This causes the machine to reply to itself continuously. It is, however, distinct from the TCP SYN Flood vulnerability.

Other LAND attacks have since been found in services like SNMP and Windows 88/tcp (kerberos/global services). Such systems had design flaws that would allow the device to accept request on the wire appearing to be from themselves, causing repeated replies.

Vulnerable systems
Below is a list of vulnerable operating systems:
 AIX 3.0
 AmigaOS AmiTCP 4.2 (Kickstart 3.0)
 BeOS  Preview release 2 PowerMac
 BSDi 2.0 and 2.1
 Digital VMS
 FreeBSD 2.2.5-RELEASE and 3.0 (Fixed after required updates)
 HP External JetDirect Print Servers
 IBM AS/400 OS7400 3.7
 Irix 5.2 and 5.3
 Mac OS MacTCP, 7.6.1 OpenTransport 1.1.2  and 8.0
 NetApp NFS server 4.1d and 4.3
 NetBSD 1.1 to 1.3 (Fixed after required updates)
 NeXTSTEP 3.0 and 3.1
 Novell 4.11
 OpenVMS 7.1 with UCX 4.1-7
 QNX 4.24
 Rhapsody Developer Release
 SCO OpenServer 5.0.2 SMP, 5.0.4
 SCO Unixware 2.1.1 and 2.1.2
 SunOS 4.1.3 and 4.1.4
 Windows 95, NT and XP SP2

Prevention
Most firewalls should intercept and discard the poison packet thus protecting the host from this attack. Some operating systems released updates fixing this security hole.

See also
 Slowloris (computer security)
 High Orbit Ion Cannon
 Low Orbit Ion Cannon
 ReDoS
 Denial-of-service attack

References

External links
Insecure.Org's original post about the attack
Article about XP's vulnerability

Denial-of-service attacks
Types of cyberattacks
Peter Hirsch (metallurgist). Sir Peter Bernhard Hirsch HonFRMS FRS (born 16 January 1925) is a British metallurgist who has made fundamental contributions to the application of transmission electron microscopy to metals.

Biography
Born in 1925, Hirsch lived in Germany until 1939; he was one of hundreds of Jewish children that escaped Germany via the various Kindertransport missions that saved many such children from the impending dangers of World War II and the Holocaust.

Hirsch attended Sloane Grammar School, Chelsea, and St Catharine's College, Cambridge. In 1946 he joined the Crystallography Department of the Cavendish to work for a PhD on work hardening in metals under W. H. Taylor and Lawrence Bragg. He subsequently carried out work, which is still cited, on the structure of coal.

In the mid-1950s, he pioneered the application of transmission electron microscopy (TEM) to metals and developed in detail the theory needed to interpret such images. He was a Fellow of Christ's College, Cambridge from 1960 to 1966 and was elected an Honorary Fellow of Christ's in 1978. In 1965, with Howie, Whelan, Pashley and Nicholson, he published the text Electron microscopy of thin crystals. The following year he moved to Oxford to take up the Isaac Wolfson Chair in Metallurgy, succeeding William Hume-Rothery. He held this post until his retirement in 1992, building up the Department of Metallurgy (now the Department of Materials) into a world-renowned centre. Among many other honours, he was awarded the 1983 Wolf Foundation Prize in physics. He was elected to the Royal Society in 1963 and knighted in 1975.

Hirsch was elected a member of the National Academy of Engineering in 2001 for experimentally establishing the role of dislocations in plastic flow and of electron microscopy as a tool for materials research. He is also a fellow of St Edmund Hall, Oxford.

His great-niece is the writer and broadcaster Afua Hirsch.

References

1925 births
Living people
Alumni of Christ's College, Cambridge
Alumni of St Catharine's College, Cambridge
British metallurgists
English people of German-Jewish descent
Fellows of St Edmund Hall, Oxford
Fellows of the Royal Microscopical Society
Fellows of the Royal Society
Foreign members of the Russian Academy of Sciences
Isaac Wolfson Professors of Metallurgy
Jewish British scientists
Knights Bachelor
Microscopists
Recipients of the Lomonosov Gold Medal
Royal Medal winners
Wolf Prize in Physics laureates
Directory System Agent. A Directory System Agent (DSA) is the element of an X.500 directory service that provides User Agents with access to a portion of the directory (usually the portion associated with a single Organizational Unit). X.500 is an international standard developed by the International Organization for Standardization (ISO), and the International Telecommunication Union (ITU-T). The model and function of a directory system agent are specified in ITU-T Recommendation X.501.

Active Directory 
In Microsoft's Active Directory the DSA is a collection of servers and daemon processes that run on Windows Server systems that provide various means for clients to access the Active Directory data store.

Clients connect to an Active Directory DSA using various communications protocols:
LDAP version 3.0—used by Windows 2000 and Windows XP clients
LDAP version 2.0
Security Account Manager (SAM) interface—used by Windows NT clients
MAPI RPC interface—used by Microsoft Exchange Server and other MAPI clients
A proprietary RPC interface—used by Active Directory DSAs to communicate with one another and replicate data amongst themselves

References

RFCs 
 RFC 2148 — Deployment of the Internet White Pages Service

Computer networking
Identity management
Curtiss XP-62. The Curtiss XP-62 was a prototype single-engine interceptor aircraft, that was built for the United States Army Air Forces, by the Curtiss-Wright Corporation. It first flew in 1943.

The design sought to have an improved high-altitude performance and higher speeds, at all altitudes, which was to be assisted by the 18-cylinder Wright R-3350 Duplex-Cyclone engine. It was to be armed with four  autocannons, a heavier armament than contemporary USAAF fighter aircraft, and was fitted with a pressurized cockpit.

Design and development
The terms of the contract proposal of 29 April 1941 called for the first flight within fifteen months of the award and meet the following objectives.
Maximum level flight speed at  had to exceed .
It was to feature an air-conditioned pressurized cockpit.
Armament to be either eight  cannons or twelve  machine guns, mounted in the wings.

Two prototypes were ordered; the first designated XP-62 and the second designated XP-62A.

On 2 August 1941, the specifications were amended for the XP-62, reducing the maximum speed to  with eight  cannons, and increasing the loaded weight by .

During a project review of 1 January 1942, the specification was again revised, with the loaded weight reduced by eliminating four cannons and removing the propeller de-icing equipment.

On 25 May 1942 a contract for 100 P-62 fighters was awarded. However, on 27 July 1942, before production could begin, the contract for the P-62 was terminated by the USAAF because of the effect on deliveries of Curtiss-built Republic P-47G-CU Thunderbolts.

While work on the XP-62A continued, it progressed slowly, owing to its low priority. Delays in delivery of the pressure-cabin supercharger and engine modifications delayed the first flight until 21 July 1943. Only a limited amount of flight testing was carried out before the XP-62A was canceled on 21 September 1943 and full performance characteristics were not obtained. The prototype was scrapped in early 1944.

Variants 
XP-62
Prototype, 8 x 20 mm cannons
P-62A
Planned initial production version, 100-aircraft contract cancelled

Specifications (XP-62)

See also

References

 Green, William. War Planes of the Second World War – Fighters, Volume 4. London: Macdonald. 1961.

External links

Curtis XP-62 – National Museum of the USAF
Wind-Tunnel Tests Of The 1/9-Scale Model Of The Curtiss XP-62 Airplane With Various Vertical Tail Arrangements – DTIC

Curtiss P-62
Single-engined tractor aircraft
P-62
Aircraft with contra-rotating propellers
Aircraft first flown in 1943
Low-wing aircraft
Aircraft with retractable conventional landing gear
Single-engined piston aircraft
ETR. ETR may refer to:

Transportation
 ElettroTreno, a series of Italian high-speed trains
 Echigo Tokimeki Railway, a railway operating company in Japan
 Santa Rosa International Airport, serving Machala, Ecuador
 Essex Terminal Railway, a short line railroad in Canada

Other
 Second East Turkestan Republic
 Edolo language; ISO language code
 Entergy Corporation; NYSE stock symbol
 Etravirine, a drug used to suppress HIV replication
 Existential theory of the reals, formal language in computer science
 Express Toll Route, in Canada; Ontario Highway 407

See also
 Xetra (trading system); XETR
 Eastern Test Range, a rocket testing area off of Cape Canaveral; ER or AFETR
Gumstix. Gumstix is an American multinational corporation headquartered in Redwood City, California. It develops and manufactures small system boards comparable in size to a stick of gum. In 2003, when it was first fully functional, it used ARM architecture system on a chip (SoC) and an operating system based on Linux 2.6 kernel. It has an online tool called Geppetto that allows users to design their own boards. In August 2013 it started a crowd-funding service to allow a group of users that want to get a custom design manufactured to share the setup costs.

See also
 Arduino
 Embedded system
 Raspberry Pi
 Stick PC

References

External links

 
 Gumstix users wiki
 Gumstix mailing list archives on nabble

Embedded Linux
Linux-based devices
Computer companies of the United States
Computer hardware companies
Companies based in Redwood City, California
Network computer (brand)
Motherboard form factors
Motherboard companies
Privately held companies based in California
Single-board computers