omniomni/omni-engineering huggingface dataset:
Hexafluorophosphoric acid. Hexafluorophosphoric acid refers to a family of salts produced by combining phosphorus pentafluoride and hydrofluoric acid. The idealized chemical formula for hexafluorophosphoric acid
is , which also is written . Hexafluorophosphoric acid is only stable in solution, decomposing to HF and PF5 when dry. It exothermically reacts with water to  produce oxonium hexafluorophosphate () and hydrofluoric acid.  Additionally, such solutions often contain products derived from hydrolysis of the P-F bonds, including , , and , and their conjugate bases. Hexafluorophosphoric acid attacks glass. Upon heating, it decomposes to generate HF. Crystalline  has been obtained as the hexahydrate, wherein  is enclosed in truncated octahedral cages defined by the water and protons. NMR spectroscopy indicates that solutions derived from this hexahydrate contain significant amounts of HF.

Whereas a species with the formula HPF6 remains unknown, the analogous molecular hexafluoroarsenic acid (HAsF6) has been crystallized.

See also
 Fluoroantimonic acid

References

Hexafluorophosphates
Mineral acids
DNA separation by silica adsorption. DNA separation by silica adsorption is a method of DNA separation that is based on DNA molecules binding to silica surfaces in the presence of certain salts and under certain pH conditions.

Operations
In order to separate DNA through silica adsorption, a sample is first lysed, releasing proteins, DNA, phospholipids, etc. from the cells. The remaining tissue is discarded. The supernatant containing the DNA is then exposed to silica in a solution with high ionic strength. The highest DNA adsorption efficiencies occur in the presence of buffer solution with a pH at or below the pKa of the surface silanol groups.

The mechanism behind DNA adsorption onto silica is not fully understood; one possible explanation involves reduction of the silica surface's negative charge due to the high ionic strength of the buffer. This decrease in surface charge leads to a decrease in the electrostatic repulsion between the negatively charged DNA and the negatively charged silica. Meanwhile, the buffer also reduces the activity of water by formatting hydrated ions. This leads to the silica surface and DNA becoming dehydrated. These conditions lead to an energetically favorable situation for DNA to adsorb to the silica surface.

A further explanation of how DNA binds to silica is based on the action of guanidinium chloride (GuHCl), which acts as a chaotrope. A chaotrope denatures biomolecules by disrupting the shell of hydration around them. This allows positively charged ions to form a salt bridge between the negatively charged silica and the negatively charged DNA backbone in high salt concentration. The DNA can then be washed with high salt and ethanol, and ultimately eluted with low salt.

After the DNA is bound to the silica it is then washed to remove contaminants and finally eluted using an elution buffer or distilled water.

See also 
Spin column-based nucleic acid purification

References

Biotechnology
Molecular biology
Molecular genetics
Comfort cab. A comfort cab is a design found on most modern North American diesel locomotives, and some export models. The broad nose occupies the entire width of the locomotive, and typically has an access door on the front of the nose.

The design may also be called a Canadian comfort cab, a North American safety cab, wide-nose, or a wide cab (although the term wide cab is somewhat of a misnomer because it is the nose, not the cab, that is widened).

History 

The basic shape of the comfort cab design first appeared on a hood unit, the EMD DDA40X, in 1969. It was the same design as the F45 and FP45 cowl units being built by EMD at the time. The cab used on the DDA40X was not a true "Safety cab" because it consisted mainly of restyled sheet metal and lacked the structural reinforcements of the Canadian design.

The first true "Safety cabs" were designed and built for the Canadian National Railway by input from railway employees. The locomotives were GP38-2s, GP40-2s and GP40-2Ls, and SD40-2s. To denote the comfort cab locomotives, a "W" was often applied at the end of the model name (i.e. GP38-2W, GP40-2W, SD40-2W), although this was not an official designation. The Montreal Locomotive Works also offered a competitive cab design on their M-420 and M-630(W) models. EMD began offering the comfort cab as a standard option instead of a custom build option in 1988.

Features 
The comfort cab design has a number of features to improve crew safety and comfort.

Safety 
The modern comfort cab design is usually built with a specially reinforced nose. Instead of sheet metal,  steel is employed with additional reinforcement behind the armor. As a moving locomotive frequently cannot stop in time to prevent collisions, these enhancements protect the crew in collisions with objects smaller than the train itself, such as downed trees or stopped automobiles. In addition, the windows of the cab meet Federal Railroad Administration Regulations Part 223,
which states that windows must withstand the impact of a .22 caliber bullet or a cinder block at .

Comfort 
The comfort cab design provides more space for the crew. It has significantly more open space than standard cabs, allowing crew members space to move about. In later years, the cab doors had improved weatherstripping and electrically heated windows installed. Many new EMD locomotives include the feature of the "Whisper Cab", a cab that is acoustically isolated from the rest of the locomotive.

References 

Locomotive parts
Railway safety
Esagu. 'eSagu' is a web-based personalized agro-advisory system which uses Information Technology to solve unscientific agricultural practices. Sagu means cultivation in the Telugu-local language of Telangana Andhra Pradesh, the region in which the project started.
E-Sagu means electronic cultivation.
It exploits the advances in Information Technology to build a cost-effective agricultural information dissemination system to disseminate expert agriculture knowledge to the farming community to improve crop productivity.

It is a joint research project of Media lab asia and IIIT Hyderabad

Recognition
 eSagu was declared the best e-governance project at the Computer Society of India (CSI) and Nihilent e-Governance Awards for 2005-06 ([Nihilent e-Governance Awards http://www.csinihilent-egovernanceawards.org])
 eSagu  features as a  select entry among  worldwide latest novel Internet applications in the book "Innovative Application Case study 2006" published by the Institute for Information Industry, a not-for-profit Think Tank for Taiwanese  Ministry of Economic Affairs in Taipei.
 eSagu was listed as one of the top three e-Governance projects (the other two are BHOOMI and SAMPARK) of India in the video film on “Next e Governance Plan”, November 2005.

References

External links
 eSagu Home Page
 Media lab asia
 Chief Coordinator
 Nihilent Technologies 

Research projects
Lithium tantalate (data page). This page provides supplementary chemical data on lithium tantalate.

Material Safety Data Sheet  

The handling of this chemical may incur notable safety precautions. It is highly recommend that you seek the Material Safety Datasheet (MSDS) for this chemical from a reliable source  such as SIRI, and follow its directions.

Structure and properties

Thermodynamic properties

Spectral data

References

 
 

Chemical data pages
Chemical data pages cleanup
Putnam model. The Putnam model is an empirical software effort estimation model created by Lawrence H. Putnam in 1978.  Measurements of a software project is collected (e.g., effort in man-years, elapsed time, and lines of code) and an equation fitted to the data using regression analysis.  Future effort estimates are made by providing size and calculating the associated effort using the equation which fit the original data (usually with some error).

SLIM (Software LIfecycle Management) is the name given by Putnam to the proprietary suite of tools his 
company QSM, Inc. developed, based on his model.  It is one of the earliest 
of these types of models developed.  Closely related software parametric models are Constructive Cost Model (COCOMO), Parametric Review of Information for Costing and Evaluation – Software (PRICE-S), and Software Evaluation and Estimation of Resources – Software Estimating Model (SEER-SEM).

A claimed advantage to this model is the simplicity of calibration.

The software equation

While managing R&D projects for the Army and later at GE, Putnam noticed software staffing profiles followed
the Rayleigh distribution.

Putnam used his observations about productivity levels to derive the software equation:

where:
 Size is the product size (whatever size estimate is used by your organization is appropriate).  Putnam uses ESLOC (Effective Source Lines of Code) throughout his books.
 B is a scaling factor and is a function of the project size.
 Productivity is the Process Productivity, the ability of a particular software organization to produce software of a given size at a particular defect rate. 
 Effort is the total effort applied to the project in person-years.
 Time is the total schedule of the project in years.

In practical use, when making an estimate for a software task the software equation is solved for effort:

An estimated software size at project completion and organizational process productivity is used.  Plotting effort as a function of time yields the Time-Effort Curve.  The points along the curve represent the estimated total effort to complete the project at some time.  One of the distinguishing features of the Putnam model is that total effort decreases as the time to complete the project is extended.  This is normally represented in other parametric models with a schedule relaxation parameter.

This estimating method is fairly sensitive to uncertainty in both size and process productivity.  
Putnam advocates obtaining process productivity by calibration:

Putnam makes a sharp distinction between 'conventional productivity' : size / effort 
and process productivity.

See also 
Software estimation

References

External links

QSM, Inc.

Software engineering costs
Ernesto Martens. Ernesto Martens Rebolledo (28 January 1933 – 13 January 2024) was a Mexican chemical engineer, who occupied several high-profile business positions and was Secretary of Energy during Vicente Fox's government.

Life and career
Ernesto Martens was born in a small town close to the Los Tuxtlas Biosphere Reserve in Veracruz. He received his bachelor's degree in chemical engineering from Tec de Monterrey, Campus Monterrey, in 1956, where he met the founder of the school Eugenio Garza Sada. He did postgraduate studies in the Karlsruhe Institute of Technology in Germany and at Harvard Business School in the United States.

His first position was with Union Carbide Headquarters where he remained for eighteen years, becoming its CEO.

In 1977, he began with a Monterrey glass company called Vitro, becoming its first non-family CEO in 1985. During his tenure, he expanded the company’s business from glass bottles into plastic containers, suitcases and washing machines with joint ventures with Ford, Corning, Samsonite and Whirlpool. He led Vitro into the U.S. glass market in the early 1980s, when Mexican demand for its products slowed and led to the only hostile takeover of a U.S. company by a Mexican company when Vitro took over Anchor Glass Container Corporation in 1989. However, he made some controversial decisions including a 1992 decision to lay off 3,000 workers, where before the company used to claim that it gave workers "a way of life".

In 1994, he became president of the board of Cintra (Corporación Internacional de Transporte Aereo), the entity which ran Mexico’s two state airlines, Aeromexico and Mexicana.  He restructured the finances and operations of the two airlines and was credited with saving them.

In 2000, Martens was named  Secretary of Energy by President Vicente Fox, a position which he held until 2003. His nomination by Fox was something of a surprise and Martens had not considered a career in government before. His appointment as energy chief was thought to be last-minute and that Fox might keep his predecessor, Luis Téllez, in the position. When he became energy secretary, PEMEX faced problems with the inability to refine oil and gas taken from Mexico's deposits, selling mostly crude.

Martens was a member of the faculty of the Tec de Monterrey and the Thunderbird School of Global Management. He died in January 2024, at the age of 90.

References

See also
List of Monterrey Institute of Technology and Higher Education faculty

1933 births
2024 deaths
Harvard University alumni
Secretaries of energy of Mexico
People from Veracruz
National Action Party (Mexico) politicians
Monterrey Institute of Technology and Higher Education alumni
Mexican chemical engineers
Academic staff of the Monterrey Institute of Technology and Higher Education
21st-century Mexican politicians
SMU Guildhall. SMU Guildhall is a graduate video game development program located at the Southern Methodist University (SMU). It was one of the first graduate video game development programs in the United States. In 2020, it was ranked #4 among the Top 25 Graduate Schools for Game Design by the Princeton Review.

History 

Originally located at the University's Plano, Texas facilities, Guildhall relocated to SMU's main campus in central Dallas at the Gerald J. Ford Hall for Research and Innovation in 2020.

Events 
 Exhibition: Students present their work at a pre-graduation exhibition. Graduation is accompanied by keynotes from established game developers. Speakers have included: Warren Spector, Gabe Newell, Jennell Jaquays, Richard Garriott, Randy Pitchford, JJ Richards, Mark Randel, Tom Hall, Ken Levine, Michael Gallagher, Ted Price, Adam Sessler, Richard Hilleman, Paul Barnett, Sr., Tim Sweeney, Greg Zeschuk, Rob Pardo, Dan Connors, Drew Murray, and Steve Nix.
 Career Fair: Semi-annual Career Fair, where studios and companies visit campus for interviews and networking.
 Open House: Semi-annual on-site event introducing the program and faculty to potential students.
 Guildhall Advanced Gaming Academy: Takes place in the summer, for middle school and high school students. Attendees learn how to make video games using Unity.
 Guest Speakers: Industry professionals speak to students and the community on various gaming topics.

External links 
 Official SMU Guildhall website

References 

Southern Methodist University
Video game universities
2003 establishments in Texas
GESMES/TS. GESMES/TS (generic statistical message for time series) is a data model and message format
appropriate for performing standardised exchange of statistical data and related metadata.
It is based on the GESMES message (a UN/CEFACT standard using the EDIFACT syntax).
Its most common use is in the exchange of official statistics.

The data model is optimised to represent multi-dimensional arrays of floating point numerical data where one dimension is time.
The essential design pattern resembles a star schema.
GESMES/TS promotes automation by its ability to explicitly declare the dimensions and allowable metadata fields in a standardised way.
Software can then translate these declarations into a database schema suitable to hold the multi-dimensional data.
This mechanism makes GESMES/TS versatile enough for efficient use in many domains.

The initial name of GESMES/TS was GESMES/CB (generic statistical message for central banks),
but has been changed in order to reflect its wider application.
The model and format are maintained under the auspices of the SDMX initiative.
In this context, GESMES/TS is known as SDMX-EDI.

References

SDMX initiative.
SDMX-EDI
A UML Model
GESMES (developed by the EBES EG6 WG1 Group)
GESMES/TS and SDMX on the web site of the European Central Bank
The OECD statistical glossary (entry: “GESMES”)

Information technology management
Group technology. Group technology or TZ is a manufacturing technique in which parts having similarities in geometry, manufacturing process and/or functions are manufactured in one location using a small number of machines or processes. Group technology is based on a general principle that many problems are similar and by grouping similar problems, a single solution can be found to a set of problems, thus saving time and effort.

The group of similar parts is known as part family and the group of machineries used to process an individual part family is known as machine cell. It is not necessary for each part of a part family to be processed by every machine of corresponding machine cell. This type of manufacturing in which a part family is produced by a machine cell is known as cellular manufacturing. 
The manufacturing efficiencies are generally increased by employing GT because the required operations may be confined to only a small cell and thus avoiding the need for transportation of in-process parts.

Group technology is an approach in which similar parts are identified and grouped together in order to take advantage of the similarities in design and production. Similarities among parts permit them to be classified into part families.

The advantage of GT can be divided into three groups:
 Engineering
 Manufacturing
 Process Planning

Disadvantages of GT Manufacturing :

Involves less manufacturing flexibility
Increases the machine down time as machines are grouped as cells which may not be functional throughout the production process.

References 

Secondary sector of the economy
Private wire. Private wire systems are localised electricity grids connected to the local distribution networks but linked to privately-owned central plant which produces electricity. This enables them to operate a stand-alone supply in the event of the national grid failing, providing localised energy security. The business case for private wire supply is driven by the fact that off-grid generation generally avoids network charges and statutory costs. Ofgem's "Significant Code Review" in the UK, launched in August 2017, includes private wire supplies within its scope.

References 

Electric power distribution
William E. Newell. Dr. William E. Newell (died 1976) was an author and "noted authority on power electronics". He worked at the Westinghouse Research and Development Center in Pittsburgh.

Influence
The William E. Newell Power Electronics Award was created in 1977 by the Power Electronics Society, and in 2005, the IEEE established another award in his name, this one called the IEEE William E. Newell Power Electronics Award.

Works
Motto, Jr., John William, (editor), Introduction to Solid State Power Electronics, Westinghouse Electric Corporation, Semiconductor Division, Youngwood, PA 15697, 1977. 143 p. edited from the posthumous notes of William E. Newell

Footnotes

References
IEEE William E. Newell Power Electronics Award
Past Recipients of the PELS Newell Award

1976 deaths
American electronics engineers
Year of birth missing
YJ-7. The YJ-7 () is a Chinese subsonic anti-ship missile. It is manufactured by the Third Academy of the China Aerospace Science and Industry Corporation (CASIC). The export version of the YJ-7 is the C-701.

History
The radar-guided C-701 was displayed by the China Precision Machinery Import-Export Corporation (CPMIEC) at the 2004 China International Aviation & Aerospace Exhibition. Although the missile was developed by the China Aerospace Science and Industry Corporation, Iran's Aerospace Industries Organisation (AIO) claimed presented the missile as a national program.

In April 2006, it was reported that radar-guided C-701s were fired during Iranian military exercises.

Variants
YJ-7
C-701 AR: Export version with active radar seeker
C-701T:  Export version with electro-optical seeker
FL-10: "Cheaper version" of the C-701
Kowsar: Iranian version of C-701

Operators

Current operators

Armed Forces of the Islamic Republic of Iran: C-701, Kowsar (patrol boats, shore batteries.)

People's Liberation Army Navy: YJ-7 (Harbin Z-8 and Z-9C helicopters)

See also
Kh-25
Sea Skua
AGM-119

References

Bibliography

Guided missiles of the People's Republic of China
Anti-ship cruise missiles of the People's Republic of China
Air-to-surface missiles
Military equipment introduced in the 2000s
Garrett TFE731. The Garrett TFE731 (now  Honeywell TFE731) is a family of geared turbofan engines commonly used on business jet aircraft. Garrett AiResearch originally designed and built the engine, which due to mergers was later produced by AlliedSignal and now Honeywell Aerospace.

Since the engine was introduced in 1972, over 11,000 engines have been built, flying over 100 million flight-hours.

Development

The TFE731 was based on the core of the TSCP700, which was specifically developed for use as the auxiliary power unit (APU) on the McDonnell Douglas DC-10. The design featured two important factors: low fuel consumption, and low noise profiles that met the newly established U.S. noise abatement regulations.

The first test run of the TFE731 occurred in 1970 at Garrett's plant in Torrance, California.  The first production model, the TFE731-2, began rolling off the assembly line in August, 1972, and was used on the Learjet 35/36 and Dassault Falcon 10, both of which entered production in 1973.

The TFE731-3 was developed for use in the Lockheed JetStar re-engining program, and subsequent versions of it have been used on a number of aircraft, including the Learjet 55.

In 1975, the TFE731 was named Aviation Product of the Year by Ziff-Davis Publishing Company.

The -5 model was certified in 1982, and a decade later, an engine utilizing the TFE731-5 power section and a TFE731-3 fan was built and designated the TFE731-4, intended to power the Cessna Citation VII aircraft.

The most recent version is the TFE731-50, based on the -60 used on the Falcon 900DX, which underwent its flight test program in 2005. Honeywell has developed this engine complete with nacelle as a candidate to retrofit a number of aircraft equipped with older engines.

Design

The TFE731-60 has an inlet diameter of 0.787 m.  The fan consists of 22 fan blades, 52 exit-guide vanes, and ten struts, and is driven by a gearbox. The five-stage compressor has four axial (LP) stages and one radial or centrifugal (HP) stage.

Variants
TFE731-2
TFE731-3
TFE731-4
TFE731-5
TFE731-20
TFE731-40
TFE731-50
TFE731-60
TFE731-1100

Applications
Jet trainers

Business jets

Specifications

See also

Notes

References

External links

 Honeywell TFE731 official website 

Centrifugal-flow turbojet engines
Geared turbofan engines
Honeywell
Medium-bypass turbofan engines
Mixed-compressor gas turbines
1970s turbofan engines