omniomni/omni-engineering huggingface dataset:
RA-4 process. RA-4 is Kodak's proprietary name for the chemical process most commonly used to make color photographic prints. It is used for both minilab wet silver halide digital printers of the types most common today in photo labs and drug stores, and for prints made with older-type optical enlargers and manual processing.

More specifically, common color photographic paper is carefully exposed to form a latent image of the picture, and then the paper is run through the series of chemicals that together comprise the RA-4 process to convert the latent image into the final print.  RA-4 uses Color Developing Agent 3, in combination with color couplers in the emulsion to generate color dyes.

RA-4 is a standardized chromogenic process used worldwide to make prints with a variety of equipment, photographic paper, and chemicals. Kodak created the RA-4 process for its color negative photographic papers. Fuji, Agfa, and other present and past photographic supply companies also make or have made both papers that are compatible with the Kodak chemicals, and chemicals that are compatible with the Kodak papers. These other companies typically call their equivalent processes by other names, but to most photographers, RA-4 is used as a generic term.

The actual chemical process occurs at 100 degrees F. The steps:
1. The paper (glossy or matte) is taken through color developer;
2. Bleach/fixer bath;
3. Stabilizer bath which both stabilizes the paper and washes out the chemicals;
4. Drying. Since the paper is Resin Coated, it dries flat and even. 

This processing can be done in a machine, e.g. in a minilab, where rotary tubes transport the film through the baths, or by the photo hobbyist in a darkroom setting, using trays for each bath.

Current manufacturers of RA-4 Chemistry include Kodak, Freestyle, Rollei, Unicolor and Tetenal as of 2017.

The result of RA-4 processing is a Type C, or chromogenic print.

References

External links 
 Process RA-4 Publication: Z-130 - Official Kodak lab manual

Photographic film processes
Kodak
Japanese gunboat Katata. was a river gunboat of the Imperial Japanese Navy, part of the 11th Gunboat Sentai, that operated on the Yangtze River in China during the 1920s, and during the Second Sino-Japanese War and World War II.

Background
Katata was the second of the  river gunboats built under the 1920 Fleet Building Program of the Imperial Japanese Navy for operations on the inland waterways of China.

Design
The basic design of Katata was modeled after that of the gunboat , with the same general dimensions and layout. Katata had a hull with an overall length of  and width of , with a normal displacement of 338 tons and draft of . She was propelled by two reciprocating engines with two Kampon boilers driving three shafts, producing  and had a top speed of 16 knots.

The ship was initially armed with two /28 cal. guns and six 7.7mm machine guns.

Service record
 Katata  was laid down on 29 April 1922 and launched 16 July 1922 at the Harima Shipyards at Aioi, Hyogo, Japan. As the design was incapable of open ocean sailing, she was then broken down into sections and shipped to the Tunghwa Shipyard in Shanghai, where she was reassembled and completed on 20 October 1923.  She was assigned to patrols of the Yangtze River from Shanghai to the Three Gorges, for commerce protection and as a show of force in protection of Japanese nationals and economic interests through the rest of the 1920s and early 1930s. Katata was commanded by Lieutenant Commander Masatomi Kimura from January to September 1932.

With the start of the Second Sino-Japanese War, Katata was based in Shanghai, and was used to evacuate Japanese residents from the interior of China. During the Battle of Shanghai, Katata  bombarded Chinese positions at Shanghai on 13 August 1937. She also helped assist in the evacuation of 20,000 of Shanghai’s 30,000 Japanese civilian residents, and covered the landings of the Imperial Japanese Army’s 3rd Division, 8th Division and 11th Divisions north of Shanghai.

Around 1940, Katata was refitted with two 3.1-in/40 cal anti-aircraft guns and five 13.2 mm Hotchkiss machine guns. She was assigned to the First China Expeditionary Fleet in December 1941. On 22 June 1942, she participated in “Operation SE” and was assigned to the Tung Ting Lake task force with gunboats  and . Around the end of 1943, her anti-aircraft weaponry was further upgraded with the replacement of the five Hotchkiss machine guns with six Type 96 AA guns.

On 12 December 1944 USAAF aircraft bombed and damaged Katata near Jiujiang, Jiangxi Province at  (she was possibly sunk and salvaged). She was towed to Shanghai and stripped of her armament in early 1945 to help bolster the land-based defenses. The hulk was bombed by USAAF P-51 Mustang fighters on 2 April 1945 and remained wrecked to the surrender of Japan.

The wreck was given to the Republic of China as war reparations in 1946 and scrapped some time later. She was officially removed from the navy list on 3 May 1947.

Notes

References

External links
 
 Japanese gunboats (with photos) 
 Monograph 144 Chapter II

Seta-class gunboats
Second Sino-Japanese War naval ships of Japan
Ships built by IHI Corporation
1922 ships
Japanese gunboat Futami. was a river gunboat of the Imperial Japanese Navy, part of the 11th Gunboat Sentai, that operated on the Yangtze River in China during the 1930s, and during the Second Sino-Japanese War and World War II.

Background
Futami was the second of two vessels in the  river gunboats built under the 1927 Fleet Building Program of the Imperial Japanese Navy for operations on the inland waterways of China.

Design
The Atami-class river gunboats were an improved version of the previous  design. Futami had a hull with an overall length of  and beam of , with a normal displacement of 338 tons and draft of . She was propelled by two reciprocating engines with two Kampon boilers driving two shafts, producing  and had a top speed of .

The ship was initially armed with one /28 caliber guns and five  machine guns.

Service record
 Futami was laid down on 25 June 1929 and launched on 20 November 1929 at the Fujinagata Shipyards in Osaka, Japan. Although most Japanese river gunboats were incapable of open ocean sailing, and had to be broken down into sections and shipped for reassembly in Shanghai,  Futami was successfully sailed to China in 1930.  She was assigned to patrols of the Yangtze River from Shanghai to the Three Gorges, for commerce protection and as a show of force in protection of Japanese nationals and economic interests from 1 June 1931. On 14 June 1933, she ran aground on uncharted rocks in the Yangtze River and could not be refloated and repaired until August.

With the start of the Second Sino-Japanese War, Futami was based in Hankou, together with the minelayer ,  and gunboats   and  and a detachment of 292 marines of the Special Naval Landing Force (SNLF) to protect Japanese residents in the interior of China.

From February to May 1939, Futami was part of the Japanese attempt to seize Battle of Nanchang under the command of the China Area Fleet's 1st China Expeditionary Fleet. She remained based out of Hankou throughout World War II and was removed from the navy list on 30 September 1945.

In 1946, she was ceded to the Republic of China as a prize of war, and commissioned into the Republic of China Navy as the Yung An (). After the Chinese Civil War and commissioned into the People's Liberation Army Navy on 30 November 1949 as the gunboat Zhu Jiang (). She was finally scrapped in the 1960s.

Notes

References

External links
 
 Japanese gunboats (with photos) 
 Monograph 144 Chapter II

Atami-class gunboats
Second Sino-Japanese War naval ships of Japan
1929 ships
Ships built by Fujinagata Shipyards
Ships of the Republic of China Navy
Ships of the People's Liberation Army Navy
Perfluorodecalin. Perfluorodecalin () is a fluorocarbon, a derivative of decalin in which all of the hydrogen atoms are replaced by fluorine atoms. It is chemically and biologically inert and stable up to 400 °C. Several applications make use of its ability to dissolve gases.

Manufacture
It is manufactured by the fluorination of tetralin or decalin with cobalt(III) fluoride in the Fowler process.  For most applications, several steps of purification are required after reaction.

Isomers
Perfluorodecalin exhibits cis-trans isomerism, as the tertiary fluorines atoms on the bridge carbon atoms can be either on the same side as each other (cis-isomer) or on opposite sides (trans-isomer). Both isomers are chemically and biologically inert and are very similar in their physical properties. The most notable difference is in the melting point, which is −3.6 °C for the cis-isomer, +18 °C for the trans-isomer, and −6.7 °C for a 50/50 mixture.

Medical applications
Of all the perfluorocarbons, perfluorodecalin has probably seen the most interest in medical applications. Most applications utilize its ability to dissolve large amounts of oxygen (100 mL of perfluorodecalin at 25 °C can dissolve 49 mL of oxygen at STP).

Perfluorodecalin was an ingredient in Fluosol, an artificial blood product developed by Green Cross Corporation in the 1980s. It is also being studied for use in liquid breathing. Perfluorodecalin can be applied topically, to provide extra oxygen to a specific location, to accelerate wound healing. Organs and tissues can be stored for longer in oxygenated perfluorodecalin; the "two-layer method" uses perfluorodecalin and UW solution to preserve tissue for pancreas transplants.

It is an ingredient of Perftoran, a blood substitute that also contains perfluoro-N-(4-methylcyclohexyl)-piperidine along with a surfactant, proxanol-268.  It was developed in Russia and as of 2005 was marketed there.

Other applications
Due to its gas-carrying capacity, perfluorodecalin has been used to enhance oxygen delivery during cell culture. Perfluorodecalin has also been shown to dramatically enhance  in vivo  microscopy resolution of airspace-containing tissues such as mesophyll. Mounting leaves in perfluorodecalin significantly improves the optical qualities of the leaf, thereby enabling high-resolution imaging over twofold deeper into the mesophyll, compared with using water.  The physiological impact of mounting the specimen in perfluorodecalin is also minimal compared to water. 

Perfluorodecalin is partially miscible with hydrocarbons which makes it an attractive inert anti-solvent for some specialized applications, such as self-organization of perovskite nanocrystals into supercrystals (also known as superlattices).

This compound is sometimes used to dissolve Teflon AF (not to be confused with other Teflons, as PTFE, PFA and FEP).

References

External links
 Safety Data Sheet 

Fluorocarbons
Halogenated solvents
Coolants
Sittwe Airport. Sittwe Airport  is an airport in Sittwe, Rakhine State, Myanmar. In Burmese it is known as စစ်တွေ လေဆိပ်.

It started as Royal Air Force station RAF Akyab, a military airfield in World War II.  It was handed over to Department of Civil Aviation by International Aero Limited Company on 24 July 1947.  It was upgraded to  long and  wide gravel mixed asphalt runway in 1960.  The airport building was extended to  from  and it was opened on 22 March 2002. 4 feet thick asphalt concrete layer was placed on the  runway, the  taxiway and the  apron and opened on 20 May 2009 for use of F-28 jets.

It is equipped with HF, VHF, NDB, Night Landing Facilities such as airfield lighting, approach light and remote control air ground machines.  It admits over 90,000 passengers in 2010-11 and it is expected to accommodate 150,000 passengers for arrival and departure yearly.

In early 2024 it was reported that conscription-age passengers arriving at this airport were interrogated by members of the Tatmadaw, with some being taken to a nearby military base to begin their period of conscripted service in the forces of the military junta due to the country's civil war.

Airlines and destinations

Accidents and incidents
On 24 August 1972, Vickers Viscount XY-ADF of Union of Burma Airways was damaged beyond economic repair when it departed the runway on landing and the undercarriage collapsed.

References

Sittwe
Airports in Myanmar
Buildings and structures in Rakhine State
Nissonite. Nissonite is a very rare copper phosphate mineral with the formula: Cu2Mg2(PO4)2(OH)2·5H2O. It crystallizes in the monoclinic crystal system typically as crusts, tabular crystals, and diamond-shaped crystals. The color is blue-green.  It has a light green streak, a Mohs hardness of 2.5 and a specific gravity of 2.73. Cleavage is {100} distinct.

Nissonite was discovered in 1966 and was named after William H. Nisson (1912–1965). It is from Llanada copper mine, near Llanada, San Benito Co., California.

References

Webmineral data
Handbook of Mineralogy
Mindat with location data

Copper minerals
Magnesium minerals
Phosphate minerals
Pentahydrate minerals
Monoclinic minerals
Minerals in space group 15
Minerals described in 1966
Geometric programming. A geometric program (GP) is an optimization problem of the form

where  are posynomials and  are monomials. In the context of geometric programming (unlike standard mathematics), a monomial is a function from  to  defined as

where  and . A posynomial is any sum of monomials.

Geometric programming is
closely related to convex optimization: any GP can be made convex by means of a change of variables. GPs have numerous applications, including component sizing in IC design, aircraft design, maximum likelihood estimation for logistic regression in statistics, and parameter tuning of positive linear systems in control theory.

Convex form
Geometric programs are not in general convex optimization problems, but they can be transformed to convex problems by a change of variables and a transformation of the objective and constraint functions.  In particular, after performing the change of variables  and taking the log of the objective and constraint functions, the functions , i.e., the posynomials, are transformed  into  log-sum-exp functions, which are convex, and the functions , i.e., the monomials, become  affine. Hence, this transformation transforms every GP into an equivalent convex program. In fact, this log-log transformation can be used to convert a larger class of problems, known as log-log convex programming (LLCP), into an equivalent convex form.

Software
Several software packages exist to assist with formulating and solving geometric programs.
 MOSEK is a commercial solver capable of solving geometric programs as well as other non-linear optimization problems.
 CVXOPT is an open-source solver for convex optimization problems.
 GPkit is a Python package for cleanly defining and manipulating geometric programming models. There are a number of example GP models written with this package here.
GGPLAB is a MATLAB toolbox for specifying and solving geometric programs (GPs) and generalized geometric programs (GGPs).
 CVXPY is a Python-embedded modeling language for specifying and solving convex optimization problems, including GPs, GGPs, and LLCPs.

See also
Signomial
Clarence Zener

References

Convex optimization
Air & Space/Smithsonian. Air & Space/Smithsonian is a quarterly magazine published by the National Air and Space Museum in Washington, D.C., United States. Its first publication was in April 1986. Articles in the magazine involve topics related to historical and present aviation and space travel. It also covers military aviation and aeronautical technology.

References

External links
 

1986 establishments in Washington, D.C.
Aviation magazines published in the United States
Bimonthly magazines published in the United States
History magazines published in the United States
Magazines established in 1986
Magazines published in Washington, D.C.
Smithsonian Institution publications
Strip algebra. Strip Algebra is a set of elements and operators for the description of carbon nanotube structures, considered as a subgroup of polyhedra, and more precisely, of polyhedra with vertices formed by three edges. This restriction is imposed on the polyhedra because carbon nanotubes are formed of sp2 carbon atoms. Strip Algebra was developed initially

for the determination of the structure connecting two arbitrary nanotubes, but has also been extended to the connection of three identical nanotubes

Background
Graphitic systems are molecules and crystals formed of carbon atoms in sp2 hybridization. Thus, the atoms are arranged on a hexagonal grid. Graphite, nanotubes, and fullerenes are examples of graphitic systems. All of them share the property that each atom is bonded to three others (3-valent).

The relation between the number of vertices, edges and faces of any finite polyhedron is given by Euler's polyhedron formula:

where e, f and v are the number of edges, faces and vertices, respectively, and g is the genus of the polyhedron, i.e., the number of "holes" in the surface. For example, a sphere is a surface of genus 0, while a torus is of genus 1.

Nomenclature
A substrip is identified by a pair of natural numbers measuring the position of the last ring in parentheses, together with the turns induced by the defect ring. The number of edges of the defect can be  extracted from these.

Elements
A Strip is defined as a set of consecutive rings, that is able to be joined with others, by sharing a side of the first or last ring.

Numerous complex structures can be formed with strips. As said before, strips have both at the beginning and at the end two connections. With strips only, can be formed two of them.

Operators
Given the definition of a strip, a set of operations may be defined. These are necessary to find out the combined result of a set of contiguous strips.

 Addition of two strips: (upcoming)
 Turn Operators: (upcoming)
 Inversion of a strip: (upcoming)

Applications
 Strip Algebra has been applied to the construction of  nanotube heterojunctions, and was first implemented in the CoNTub v1.0 software, which makes it possible to find the precise position of all the carbon rings needed to produce a heterojunction with arbitrary indices and chirality from two nanotubes.

References 

Carbon nanotubes
Newlincs EfW facility. The Newlincs EfW facility is an energy from waste facility which is located in Grimsby, North East Lincolnshire, England. The plant is operated by Cyclerval UK & TIRU Group under a PFI contract. The engineering of the facility is unusual as it consists of an oscillating kiln handling 56,000 tonnes of waste per year/7 tonnes per hour of waste. The facility is capable of generating 3.2 MW electricity.

See also
List of incinerators in the UK

References

External links

Newlincs
Photo of facility

Buildings and structures in Grimsby
Brush HMA. Brush HMA is a manufacturer of large generators for gas turbine and steam turbine drive applications, based at Ridderkerk in the Netherlands.

History
The business began back in November 1882 when two young Dutch entrepreneurs, Adriaan Pot and Willem Smit established a company called Elektrisch Licht-Machinen Fabriek Willem Smit & Co.. Later, the name changed to Smit Slikkerveer. In the early days, the company manufactured various electrical products including dynamos and lighting equipment. This was followed by direct current (DC) and alternating current (AC) electric motors, generators, drives and transformers.

In 1962, following a merger between Smit Slikkerveer and the dominant Heemaf Hengelo along with several other companies, the new name of Samenwerkende Elektrotechische Fabrieken Holec N.V. was created. During the 1980s, the company, which was simply known as Holec Machines and Apparaten (HOLEC), was suffering from failing business due to downturns and changes in old industries, such as the shipbuilding industry. The resulting economics required more restructuring to meet the uncertainty. 

In 1989, the Holec Machines and Appararten business along with associated sister companies were taken over by the Royal Begemann Group, which provided considerable capital investment for the new plants, and equipment required to keep the divisions viable and competitive in a global marketplace. It also allowed Holec to move further into traction electrical machines. 

In March 1998, the division of what had been the old Smit Slikkerveer was split into two smaller but focussed business units, HMA Power Systems and Traxis BV. Traxis BV focussed on traction control equipment whereas the larger HMA Power Systems concentrated on its core business of medium to large AC generators, DC traction motors, associated control equipment, and service and repair work.

Early in 2000, HMA Power Systems was purchased outright by FKI plc which was in turn purchased by private equity company Melrose plc in 2008. It is now part of the larger group Brush Turbo Generators, the Brush HMA element of which currently employs approximately three hundred fifty staff across its range of manufacturing shops, design and development offices.

Facilities
The Brush HMA manufacturing plant is located adjacent to the river, north of Ridderkerk, near Rotterdam in the Netherlands.

The Brush HMA plant at Ridderkerk, not to be confused with the other Holec Ridderkerk enterprise that became part of France's Alstom, has manufactured many different types of electrical machines and associated equipment over the last one hundred twenty years. Today its core business is centred on the manufacture of medium-sized four pole turbo-generators (Brush Turbogenerator Division centre of excellence), AC traction motors and service and repair of electrical machines. In the four pole turbogenerator range, the principal product is the DG range, which is sold globally to all major oil and gas companies.

References

External links
Aftermarket website NL
Brush website

Companies based in South Holland
Organisations based in Ridderkerk
Mosquito (missile). The Mosquito was an Italian wire-guided anti-tank missile developed by the Swiss firm Contraves AG in close cooperation with the German firm of Bölkow, and produced by its Italian subsidiary Contraves Italiana SpA. It entered service with the Italian Army in 1961 and Indonesian armed forces. It was broadly similar to anti-tank missiles of the era, having a fibreglass body with four large wings, cruciform in cross-section and a relatively short body.

The missile is transported in a cuboid container that also acts as a launcher. The launcher is attached to a control box that is equipped with a binocular sight and control joystick. When the missile is launched the operator steers the missile using the joystick. He first "gathers" the missile to his line of sight to the target.

It is steered in flight by vibrating spoilers in the wings, and spins for additional stabilization, with a pyrotechnically spun gyroscope providing stabilization. Some Mosquito missiles are on display at the Schweizerisches Militärmuseum Full.

Operators

Specifications

 Length: 1.11 m 
 Diameter: 0.12 m
 Wingspan: 0.6 m
 Weight: 14.1 kg
 Range 350 m to 2400 m
 Peak speed: 90 m/s
 Warhead: Either 4 kg hollow charge (660 mm versus RHA) or fragmentation
 Propulsion: Two-stage solid rocket motor.

References

 
 Schweizerische Militärmuseum Full

Anti-tank guided missiles of the Cold War
Guided missiles of Italy
Military equipment introduced in the 1960s