omniomni/omni-engineering huggingface dataset:
Powerhead (pump). An aquarium powerhead is a water pump completely submerged into an aquarium to circulate water.

Description 

An aquarium powerhead is typically used to create flow throughout the tank. For example, a single powerhead could be used at one end of a freshwater aquarium to simulate a laminar river current, or multiple powerheads can be positioned throughout the aquarium to create more turbulent flow. 

A switching or variable-voltage system (also known as a "wavemaker") is commonly used in reef aquaria to more closely simulate the movement of ocean water. 

Water circulation is vital to proper biological filtration of most saltwater aquaria (particularly those using the Berlin Method), and is useful in freshwater aquaria for allowing free-swimming fish adequate exercise.

References

Fishkeeping
Inertial number. The Inertial number  is a dimensionless quantity which quantifies the significance of dynamic effects on the flow of a granular material. It measures the ratio of inertial forces of grains to imposed forces: a small value corresponds to the quasi-static state, while a high value corresponds to the inertial state or even the "dynamic" state. It is given by:

where  is the shear rate,  the average particle diameter,  is the pressure and  is the density.

Generally three regimes are distinguished:
 : quasi static flow
 : dense flow
 : collisional flow

One model of dense granular flows, the μ(I) rheology, asserts that the coefficient of friction μ of a granular material is a function of the inertial number only.

References

Granularity of materials
Dethatcher. A dethatcher or lawn scarifier is a device that removes thatch from lawns. Types of dethatchers include motorized dethatchers or those that can be pulled behind a garden tractor.

Thatch removal (dethatching) 

Scarification or de-thatching of lawns or turf is a mechanical process whereby the surface and subsurface of the lawn, green or sports pitch is rigorously abraded by penetrating metal blades, tines or prongs. 

The process is usually carried out by machines of a professional standard which are normally powered by gasoline engines. Smaller, less rigorous electric machines are also available for the domestic market. The process of scarifying is designed to remove thatch from lawns.

Thatch is a build-up of organic matter which can include dead grass, leaves, stems, stolons, rhizomes and overcrowded grass roots and lateral weed growth. Thatch can stifle the growth and health of grass or turf. Removing the thatch helps the grass by encouraging it to thicken up and also makes it stronger and less susceptible to disease. Reducing thatch levels increases the levels of water, air and nutrients that can get through to the root zone of the grass plants. Significant thatch problems in lawns can cause diseases and can encourage moss to grow in the areas where grass has died. A by-product of scarifying or de-thatching is that moss is also removed, and depending on how deep the scarifying blades are set, root cutting can also occur, and this in turn helps grass to thicken up over time. Scarifying is normally carried out in autumn or spring. When scarifying or de-thatching, not all thatch should be removed as a small amount of thatch is beneficial to the lawn. A lawn that has excessive thatch may feel spongy when trodden upon. After removing thatch, it can be swept or raked up using a lawn sweeper.

References

External links

Gardening tools
Horticultural techniques
Lawn care
Renwu incident. The Renwu incident was a soil pollution event at the Formosa Plastics Corporation's Renwu Plant in Kaohsiung, Taiwan.

In 2009, the Taiwanese Environmental Protection Administration (EPA) found that the soil and the groundwater in the area close to Formosa Plastics' Renwu Plant has been polluted by benzene, chloroform, dichloromethane, 1,1,2-Trichloroethane, 1,1-dichloroethylene, tetrachloroethylene, trichloroethylene, and vinylchloride. The pollutants were all present at levels over 20 times the government standard; and most frighteningly, the levels of 1,2-dichloroethane were 30,000 times higher than the standard.

The Formosa Plastics' Renwu Plant had already discovered the soil pollution in 2006, and they had tried to reinforce the structure of their wastewater pit, but the reinforcement work was never completed.

Since the pollution was severe, the residents of the nearby area and an Elected Representative lodged protests, hoping that the Renwu plant could shut down. In April 2010, the EPA proposed a fine on Formosa Plastic' Renwu Plant to NT$150 million (US$4.7 million) for causing soil and groundwater pollution.

References 

Soil contamination
Environment of Taiwan
2009 in Taiwan
Formosa Plastics Group
SNCF Class BB 10003. The locomotive SNCF BB 10003 was an experimental prototype locomotive converted from a SNCF BB 15000 electric locomotive and used to develop the use of asynchronous induction traction motors.

History
The locomotive BB 10003 was created from an earlier experimental machine BB 7003 in 1982. It was used to test the use of asynchronous induction motors in locomotives.

From 1986 to 1987 the locomotive was used in experiments testing the viability of a diesel electric locomotive with asynchronous traction motors; the locomotive was coupled to a remotorised SNCF CC 72000 locomotive which acted as an electrical generator.

In 1990/1 the locomotive was used as a test machine for operations of the TGV-TMST on 750 V and 3000 V. In 1998 the locomotive was converted back to a non-experimental class - as SNCF BB 15007. (SNCF Class BB 15000)

Legacy
The results were not as good as synchronous motor technology; it was not until the introduction of GTO transistor technology that series production of an asynchronous induction motored locomotive began in France, as the Eurostar TGV (1992), and later the BB 36000 Astride (1996).

Notes

References

External links

Alstom locomotives
10003
Standard gauge electric locomotives of France
Experimental locomotives
Railway locomotives introduced in 1982
Rosickýite. Rosickyite is a rare native element mineral that is a polymorph of sulfur. It crystallizes in the monoclinic crystal system and is a high temperature, high density polymorph. It occurs as soft, colorless to pale yellow crystals and efflorescences.

It was first described in 1930 for an occurrence in Havirna, near Letovice, Moravia, Czech Republic.  It was named for Vojtĕch Rosický (1880–1942), of Masaryk University, Brno.

Rosickyite occurs as in Death Valley within an evaporite layer produced by a microbial community. The otherwise unstable polymorph was produced and stabilized within a cyanobacteria dominated layer.

References

Native element minerals
Monoclinic minerals
Minerals in space group 13
Sulfur
Polymorphism (materials science)
CrucialTec. CrucialTec is the world's largest manufacturer of Optical Track Pad (OTP) mobile input devices. Headquartered in Seongnam, South Korea, the company manufactures and supplies OTP devices to handset manufacturers such as Research In Motion, Samsung, LG, HTC, Sony, Motorola, Pantech and ZTE. CrucialTec is also a supplier of devices for smart TVs and digital cameras to companies like HP, Sharp, Kyocera, and Acer. The company developed and commercialized the world's first nano-optic based input device and holds over 200 patents worldwide.
 
In 2010, CrucialTec had sales of $208 million and is targeting $1 billion in revenues by 2013. In July 2011, CrucialTec opened its Vietnam manufacturing plant in Hanoi with an expected manufacturing capacity of 100 million units per year.

In March 2012, CrucialTec signed a JDA with Swedish biometrics manufacturer Fingerprint Cards AB (FPC) to integrate their swipe sensor into CrucialTec's upcoming Biometric Track Pad (BTP).  This led to a three-year supply agreement amendment in November of the same year to produce the BTP which will be assembled in CrucialTec's Korea plants.

References

External links 

Bloomberg Businessweek CrucialTec profile

Manufacturing companies of South Korea
Technology companies of South Korea
Manufacturing companies established in 2001
South Korean brands
South Korean companies established in 2001
MicroDigital Omega. The MicroDigital Omega was a home computer developed and sold in the early 2000s by MicroDigital. It runs the RISC OS operating system.

The Omega suffered a protracted development, announced in 2000, it was released in 2003.

References

External links
Foundation - Alpha Omega
Steffen Huber - Benchmarks - MicroDigital Omega vs. Castle IYONIX pc
RiscWorld - MicroDigital Omega Press Day
MicroDigital - The NewsDesk - Saturday 12 July 2003
The Qube RiscOS Server - Acorn and Related Systems - MicroDigital Omega
RISC OS User Group Of London - OMEGeddon!
RiscWorld - The MicroDigital Omega
Drobe - MicroDigital's Omega priorities
Drobe - MicroDigital's domain expires
Drobe - MicroDigital sought by bailiffs
Drobe - MicroDigital incommunicado

RISC OS
ARM-based home computers
Microcomputers
Computer-related introductions in 2003
Skike. A skike is a sports device consisting of two wheels attached to a frame that can be strapped onto the rider's shoe. Similarly to roller skis, the skike has a wheel in front and at the tail of an aluminium frame that can be attached to the foot. However, unlike roller skis and roller skates the tires are pneumatic. In addition to asphalt, the skikes can therefore be used on rougher terrain such as dirt roads, plaster and gravel. The skike straps onto the rider's shoe, and does not require any special type of boot. It has a brake on the heel that allows the rider to stop or brake gradually by pushing back the lower legs.

The name skike is a combination of skate and bike. The skike rider moves forward in a skating motion, usually with poles, similarly to normal cross country skate skiing. Certain models such as the V9 200 series with ratcheted front wheels also allow skiing in the "classic" XC style. 

The skike was invented by Otto Eder in 1997.

Supporters of the skike claim it gives great all-round exercise similar to cross-country roller skiing, but with the benefits of being able to brake easily and utilize more varied type of terrain.

References

External links 
 skike.com
 skike.me in the US and Canada

Inline skating
VirtualAcorn. VirtualAcorn is the brand name of several commercial emulators of Acorn Computers computer hardware platforms.

Development

VirtualAcorn is developed by Graeme Barnes and Aaron Timbrell. It is a commercial version of the freeware emulator Red Squirrel, developed by Barnes. In 2004, supply of the software was moved to Timbrell's company 3QD Developments.

Virtual A5000

Virtual A5000 is an emulator of Acorn Computers A5000 computer. It included a copy of RISC OS 3.11. Virtual A5000 was released at BETT 2002 and stopped shipping in 2004.

It is now commercially available again from riscos.com with the latest version dated 2014.

VirtualRPC

VirtualRPC is an emulator of Acorn Computers' Risc PC computer.

Initially VirtualRPC was only available bundled with the MicroDigital Alpha range of PC laptops, but was later made available as a standalone product for sale. In 2003, the developers reached an agreement with RISCOS Ltd to license its OS.

VirtualRPC comes in four versions, with support for emulating ARM7 or ARM7 and StrongARM each coming with either RISC OS 4.02 or RISC OS Adjust 4.39.

Hardware bundles
Initially VirtualRPC was included on the MicroDigital Alpha range of PC laptops, and it has also been shipped by Advantage Six on the A5 series and by R-Comp in their RISCube/SpaceCube/RiscBook range.

References

External links
 http://www.drobe.co.uk/riscos/article.php?id=1600&nc=17
 http://www.drobe.co.uk/article.php?id=799 Drobe - Virtual License

Windows emulation software
MacOS emulation software
Cross-platform software
RISC OS emulators
Proprietary software
Transport in South Sudan. 

Railways 

total: 
narrow gauge:   gauge.

South Sudan has a total of  of narrow-gauge, single-track railroad line in the country. The only line in the country is partially used and it connects to Babonosa (north Sudan) with Wau. Most of the line was mined and badly destroyed during the Second Sudanese Civil War. Around January 27, 2008; the line was fully rehabilitated with United Nations funds.

Railway links with adjacent countries 
  Sudan – yes – Babanusa to Wau line - (1959-1962, 2010–present)

Highways 
Under Sudanese rule a number of main gravel roads radiating from Juba were improved. These included roads to the towns southwest of Juba and a road to the Ugandan border. In addition, the government built a gravel all-weather road east of Juba that reaches the Kenyan border. There it joined an all-weather Kenyan road to Lodwar connecting it to the Kenyan road system. However, all of these improvements radiating from Juba have been vitiated by the civil war, as the roads have been extensively mined by the SPLA and the bridges destroyed. Because roads have not been maintained, they have seriously deteriorated.

Highways in South Sudan are almost entirely unpaved. Rehabilitation work is underway and the first paved highway between the country's capital Juba and Nimule in the Uganda border has opened.

Inventory
The total road network in 2017, according to the UNJLC, consisted of:

Total: 
Paved: 
Unpaved:  (2017)

Roadways

Juba-Nimule Road
Gulu–Nimule Road

Regional highways

North-South

East-West

Waterways 
The Nile river is navigable only on some stretches.

The White Nile is a navigable waterway from the Lake Albert (Africa) to Khartoum through Jebel Aulia Dam, only between Juba and Uganda requires the river upgrade or channel to make it navigable.

During part of the year the rivers are navigable up to Gambela, Ethiopia, and Wau, South Sudan.

Pipelines 
A single pipeline leads from South Sudan's oil fields to (north) Sudan's only seaport, Port Sudan.

Air

The busiest and most developed airport in South Sudan is Juba International Airport, which has regular international connections to Entebbe, Nairobi, Cairo, Addis Ababa, and Khartoum. Juba Airport is also the home base of Feeder Airlines Company. Other international airports include Malakal, with international flights to Addis Ababa and Khartoum; Wau, with weekly service to Khartoum; and Rumbek, also with weekly flights to Khartoum.

Southern Sudan Airlines also serves Nimule and Akobo, the airstrips of which are unpaved. There are several smaller airports throughout South Sudan, the majority of which consist of little more than dirt airstrips.

Airports - with paved runways 
total:  
over : 0
: 0
:  (2017 est.)

Airports - with unpaved runways 
total: 0
: 0
: 0
under : 0 (2017 est.)

See also

 Ministry of Transport and Roads (South Sudan)
 Lamu Port and Lamu-Southern Sudan-Ethiopia Transport Corridor

References

External links
 Nile inland Waterways
 South Sudan Waterway Assessment
 Feasibility study river barge system (Cranes on trucks/loader cranes and pallets can increase efficiency)
International Symposium on Power Semiconductor Devices and ICs. ISPSD (International Symposium on Power Semiconductor Devices and ICs) is an annual conference established in 1988 by the Institute of Electrical and Electronics Engineers (IEEE) on a wide range of power technologies.  Host to over 500 experts from across the world, ISPSD is the premier forum for technical discussions in all areas of power semiconductor devices and power integrated circuits, recently focusing on gallium nitride and silicon carbide devices.

The conferences are held in Asia, North America, and Europe on a rotating basis. ISPSD celebrated its 30th anniversary in Chicago, United States from May 13 to 17, 2018. The previous year's conference was held in Sapporo, Japan from May 28 to June 1, 2017. ISPSD 2016 was held in Prague, Czech Republic in June 2016. ISPSD 2019 was held in May 2019 in Shanghai, China.

References

Technology conferences
IEEE conferences
Semiconductor devices
List of additives used for fracking. The differences between additives for fracking in different countries are the type of chemicals used (hazardous, non-hazardous), the disclosure of chemicals and the composition of fracturing fluid. In 2010, Halliburton announced the creation of food additive based hydraulic fracturing fluid in response to calls for transparency and demand for a "more environmentally friendly" unconventional hydrocarbon production.

Europe

In Europe, Poland, Norway and Germany have the largest reserves of shale gas, and drillings are underway.

United Kingdom
In the United Kingdom, the environmental regulator permits only chemical additives which are classed as non hazardous to groundwater for fracturing fluids. Operators are required to disclose the content of hydraulic fracturing fluids to the relevant environment agency while the composition must be disclosed if the regulator demands it. The permitted additives for hydraulic fracturing fluid include polycrylamide, hydrochloric acid and a biocide.

United States
In the US, about 750 compounds have been listed as additives for hydraulic fracturing, also known as ingredients of pressurized fracking fluid, in an industry report to the US Congress in 2011 The following is a partial list of the chemical constituents in additives that are used or may have been used in fracturing operations.

See also
 Hydraulic fracturing
 Hydraulic fracturing in the United Kingdom
 Hydraulic fracturing in the United States
 Hydraulic fracturing proppants
 Uses of radioactivity in oil and gas wells

References

Hydraulic fracturing
Water and the environment
Chemistry-related lists
Roger Van Overstraeten. Roger Joseph, Baron Van Overstraeten (7 December 1937, Vlezenbeek – 29 April 1999, Leuven) was a professor at the Catholic University of Leuven and later the Katholieke Universiteit te Leuven, an IEEE Fellow and the founder of the micro- and nanoelectronics research center IMEC.

Van Overstraeten earned a PhD from Stanford University in 1963.

Honors and awards
In 1989 he was awarded the first Becquerel Prize by the European Commission.

In 1990 Van Overstraeten was elevated to Baron and he received the IEEE Frederik Philips Award (1999).

References

1937 births
1999 deaths
Fellows of the IEEE
Stanford University alumni
Academic staff of KU Leuven
People from Sint-Pieters-Leeuw
Information display systems. "Information display systems" (IDS) is the general designation for the control panels and displays of Russian (and previous Soviet) spacecraft. For example, the original Soyuz 7K-OK spacecraft used the "Sirius-7k" IDS.

See also
Voskhod Spacecraft Globus IMP navigation instrument

References
Information Display Systems for Russian Spacecraft: An Overview

Soviet computer systems
Science and technology in Russia
Space program of Russia
Space program of the Soviet Union
Hütter Hü 17. The Hütter Hü 17, is a German high-wing, strut-braced, single-seat, utility training glider that was designed by brothers Ulrich Hütter and Wolfgang Hütter in the 1930s.

The aircraft's correct designation is unclear and various sources refer to is as the Hütter Hü 17, Hütter-17, Hütter H-17, Hutter H-17, Hütter Hü-17, Göppingen Gö 5 and Goppingen 5.

Design and development
The Hütter brothers designed the Hü 17 in Salzburg, Austria, the designation indicating the aircraft's glide ratio. The design was made available as plans for amateur construction and several hundred were completed. The brothers then joined the Schempp-Hirth company which constructed about five of the aircraft under the designation Göppingen Gö 5.

The aircraft is of wooden construction, using a D-tube wing with a single strut and doped aircraft fabric covering. The wing employs a Göppingen 535 airfoil at the wing root and a NACA M-6 at the wing tip. The fuselage is plywood covered.

Operational history
In the 1980s a number of aircraft were still flying in Australia, West Germany, the United Kingdom and the United States. In July 2011 one example was registered with the American Federal Aviation Administration in the Experimental - Exhibition category, having been constructed in 1990.

Variants

Hü 17
Initial model with a  wing span
Hü 17B
Improved model, introduced after the Second World War with increased wing span and higher empty and gross weights
Göppingen Gö 5
Model built by Schempp-Hirth
TG-24
USAAF designation for one impressed Gö 5 (serial number 42-57185)
CAT 20
Italian licence build, 1938. Over 20 produced.

Aircraft on display
National Soaring Museum
Technisches Museum Wien

Specifications (Hü 17b)

See also

References

External links

1930s German sailplanes
Hütter aircraft
High-wing aircraft
Glider aircraft
Aircraft with skid landing gear
Alec Gambling. William Alexander Gambling (11 October 1926–9 January 2021) was a British electrical engineer.

Life
From 1950 to 1955, he was lecturer in electric power engineering at the University of Liverpool.
He taught at the University of Southampton and was dean of Engineering and Applied Sciences from 1972 to 1975.

He was president of Institution of Electronic and Radio Engineers in 1978. In 1979, he was elected a Fellow of the Royal Academy of Engineering

He was BT professor of optical communications from 1980 to 1995 and founder and director of the Optoelectronics Research Centre from 1989 to 1995.

He was Royal Society Kan Tong Po visiting professor at the University of Hong Kong from 1996 to 2001.  He was director of Research and Development at Optoelectronics LTK Industries Ltd from 2002 to 2007.

He was awarded the James Alfred Ewing Medal in 2002. He died in Spain on 9 January 2021.

Works
Electronics in transition, University of Southampton, 1968
Photons and fibres: the new world of communications, Royal Academy of Engineering, 1992
S. T. Lee, P. S. Chung, William Alexander Gambling, C. S. Lee, Papers presented at the Asia-Pacific Symposium on Organic Electrolumuniscent Materials and Devices, City University of Hong Kong, 2000

References

External links
http://www.patentbuddy.com/Inventor/Gambling-William-Alexander/3683321

1926 births
2021 deaths
British electrical engineers
Fellows of the Royal Society