omniomni/omni-engineering huggingface dataset:
PZL M26 Iskierka. PZL M26 Iskierka () or M26 Airwolf is a Polish trainer and aerobatic aircraft, designed at WSK PZL-Mielec (later PZL Mielec).

Design and development
The M26 Iskierka was conceived as an economical plane for civilian pilot training and primary selection of military pilots. It offers training in both VFR and IFR flying as well as aerobatics. Its construction is partly based upon the twin-engine PZL M-20 Mewa utility plane (Piper PA-34 Seneca II, built under licence in WSK-Mielec). It shares the vertical stabilizer, rudder and main landing gear with the Mewa, while the wings and tail part of fuselage are unified to some degree. The plane is constructed according to FAR-23 rules. The main designer was Krzysztof Piwek.

The first prototype M26-00, powered by a PZL-Franklin 6A-350C1 air-cooled flat-six engine rated at , flew first on July 15, 1986. The second prototype was the more powerful M26-01 variant, powered by a  Lycoming AEIO-540-L1B5D engine, and first flew on June 24, 1987. It was tested in a military aviation school in Dęblin in 1992.

Only a short series of 9 aircraft were manufactured, of which one remains in Poland. The plane is still offered by the PZL Mielec and is certified in the US, Australia and Europe (EASA). In the USA it is offered under the name Airwolf or Air Wolf, and eight  were exported there, beginning from 1996. In 1998 two were delivered to the Venezuelan National Guard. There were plans to fit a Walter M601 turboprop engine, for eventual customers' demand, however it was determined that the changes to the airframe would be significant and the project was abandoned.

Description
The M26 Iskierka is a low-wing monoplane, conventional in layout, metal covered with a semi-monocoque fuselage. Rectangular single-spar wings. Crew of two, sitting in tandem, under a common canopy, with double controls (student in front, instructor in rear). The rear seat is raised by 15 cm. The canopy is dropped in emergency. Retractable tricycle landing gear. Three-blade propeller (1.9 m diameter). Fuel tanks in wings (377 L). The plane may be fitted with a camera gun and racks for two small bombs.

Operators

Specifications (M26 01)

See also

References

Krzysztof Piwek, Wiesław Tomecki: Samolot M26 Iskierka in: Polska Technika Lotnicza - Materiały Historyczne 10(3/2005) - a lecture given on 19-2-2005 in Muzeum Techniki, Warsaw 
 Lambert, Mark (ed.) Jane's All The World's Aircraft 1993–94. Coulsdon, UK:Jane's Data Division, 1993. .
 "Poland's Novel Tuitional Trio". Air International, Volume 32, No. 5, May 1987. pp. 227–231. .

External links

PZL Mielec page

1980s Polish civil trainer aircraft
1980s Polish military trainer aircraft
M26
Single-engined tractor aircraft
Low-wing aircraft
Aircraft first flown in 1986
Thermally conductive pad. In computing and electronics, thermal pads (also called thermally conductive pad or thermal interface pad) are pre-formed rectangles of solid material (often paraffin wax or silicone based) commonly found on the underside of heatsinks to aid the conduction of heat away from the component being cooled (such as a CPU or another chip) and into the heatsink (usually made from aluminium or copper). Thermal pads and thermal compound are used to fill air gaps caused by imperfectly flat or smooth surfaces which should be in thermal contact; they would not be needed between perfectly flat and smooth surfaces. Thermal pads are relatively firm at room temperature, but become soft and are able to fill gaps at higher temperatures. Some, but not all, types of chip carriers include thermal pads in their design.

It is an alternative to thermal paste to be used as thermal interface material. AMD and Intel have included thermal pads on the bottom of heatsinks shipped with some of their processors, as they are cleaner and generally easier to install. However, thermal pads conduct heat less effectively than a minimal amount of thermal paste.

See also
 Computer cooling
 Hot-melt adhesive
 Phase-change material
 Thermal adhesive
 Thermal paste
 List of thermal conductivities

References 

Computer hardware cooling
Cooling technology
Heat conduction
Thermally conductive pad
MPEG program stream. Program stream (PS or MPEG-PS) is a container format for multiplexing digital audio, video and more. The PS format is specified in MPEG-1 Part 1 (ISO/IEC 11172-1) and MPEG-2 Part 1, Systems (ISO/IEC standard 13818-1/ITU-T H.222.0). The MPEG-2 Program Stream is analogous and similar to ISO/IEC 11172 Systems layer and it is forward compatible.

Program streams are used on DVD-Video discs and HD DVD video discs, but with some restrictions and extensions. The filename extensions are VOB and EVO respectively.

Coding structure
Program streams are created by combining one or more Packetized Elementary Streams (PES), which have a common time base, into a single stream. It is designed for reasonably reliable media such as disks, in contrast to MPEG transport stream which is for data transmission in which loss of data is likely. Program streams have variable size records and minimal use of start codes which would make over the air reception difficult, but has less overhead. Program stream coding layer allows only one program of one or more elementary streams to be packaged into a single stream, in contrast to transport stream, which allows multiple programs.

MPEG-2 Program stream can contain MPEG-1 Part 2 video, MPEG-2 Part 2 video, MPEG-1 Part 3 audio (MP3, MP2, MP1) or MPEG-2 Part 3 audio. It can also contain MPEG-4 Part 2 video, MPEG-2 Part 7 audio (AAC) or MPEG-4 Part 3 (AAC) audio, but they are rarely used. The MPEG-2 Program stream has provisions for non-standard data (e.g. AC-3 audio or subtitles) in the form of so-called private streams. International Organization for Standardization authorized SMPTE Registration Authority, LLC as the registration authority for MPEG-2 format identifiers. It publishes a list of compression formats which can be encapsulated in MPEG-2 transport stream and program stream.

Coding details

See also
Elementary stream
MPEG transport stream

References

External links
 MPEG-2
 Official MPEG web site
 BBC On MPEG
 RFC 3555 - MIME Type Registration of RTP Payload Formats (video/MP2P, video/MP1S)

Digital container formats
MPEG
MPEG-2
ITU-T recommendations
Roger R. Schell. Roger R. Schell is president of ÆSec, a company focused on appliances for e-business on the Internet. For several years, he managed the development and delivery of security for several Novell releases of network software products including an integral PKI, an international crypto API, and an authentication service with exposed SSL capability. Schell was co-founder and vice president for Engineering of Gemini Computers, Inc., where he directed development of Gemini's Class A1 network processor commercial product. He was also the founding deputy director of the (now) National Computer Security Center. Previously he was an associate professor of computer science at the Naval Postgraduate School.

Biography
Schell was born in Richey, Montana. His family moved to Belgrade, Montana when he was in high school. Schell attended Montana State University (MSU), where he graduated from the ROTC program with a degree in electrical engineering. The U.S. Air Force sponsored his graduate studies at Washington State University (WSU). He earned a master's degree in electrical engineering in 1963.

The Air Force then assigned him to the Electronics Systems Division at Hanscom Air Force Base in Bedford, Massachusetts, where he worked on the Ballistic Missile Early Warning System and later on the Semi-Automatic Ground Environment (SAGE) system. During this work on SAGE, he became more involved in computer programming.

As a skilled engineer working for the Air Force, Schell was constantly pressured during these years to return to graduate school. He persuaded his officers to send him to MIT. In 1971, Schell graduated from MIT with a PhD in computer science.  He wrote one of the earliest Multics security dissertations, "Dynamic Reconfiguration in a Modular Computer System."

Schell originated several security design and evaluation techniques and holds patents in cryptography and authentication. He has been referred to as the "father" of the Trusted Computer System Evaluation Criteria (the "Orange Book"). The NIST and NSA have recognized Dr. Schell with the National Computer System Security Award.

Publications
 
 
 Karger, Paul A. and Roger R. Schell (2002). “Thirty Years Later: Lessons from the Multics Security Evaluation”, ACSAC '02 Proceedings of the 18th Annual Computer Security Applications Conference
 
 Schell, Roger R. (January–February 1979). “Computer Security: The Achilles' Heel of the Electronic Air Force?” Air University Review 30(2)

Notes

References
 Roger R. Schell, oral history interview by Jeffrey R. Yost (May 1, 2012). Charles Babbage Institute, University of Minnesota.

Further reading

External links
 Past NCSSA Winners 

Living people
MIT School of Engineering alumni
Naval Postgraduate School faculty
Computer security academics
People from Dawson County, Montana
People from Belgrade, Montana
Montana State University alumni
Washington State University alumni
Year of birth missing (living people)
Copper pour. In electronics, the term copper pour refers to an area on a printed circuit board filled with copper (the metal used to make connections in printed circuit boards). Copper pour is commonly used to create a ground plane. Another reason for using copper pour is to reduce the amount of etching fluid used during manufacturing.

Features
A distinctive feature of copper pour is the backoff (or stand-off) - a certain distance between the copper pour and any tracks or pads not belonging to the same electrical net. A copper pour therefore looks like it flows around other components, with the exception of pads which are connected to the copper pour using thermal connections.

Many early PCBs have a "hatched copper pour", sometimes called a "cherry pie lattice". PCB designers today almost always use completely solid areas of copper pour that completely cover the remaining area outside those tracks, pads, and stand-off regions.

While solid copper pour provides better resistive characteristics, hatched copper pour is used to balance the heat and dilatation on both sides of the board in order to avoid warping of certain substrate. Heating might cause gas bubbles between solid copper pour and certain substrates. Furthermore, it might be possible to adjust the impedance of high frequency traces by using hatched copper pour in order to reach better signal quality.

See also

References

External links
Integrated Circuit Components
Printed Circuit Board Assembly

Printed circuit board manufacturing
Armored Combat Engineer Robot. The Armored Combat Engineer Robot (ACER) is a military robot created by Mesa Robotics. Roughly the size of a small bulldozer and weighing 2.25 tons, ACER is among the larger military robots. ACER is able to reach speeds of 6.3 mph, using treads for movement. Uses for this robot include clearing obstacles, removing explosives, hauling cargo and disabled vehicles, and serving as a platform for various other tasks, such as clearing buildings and disarming landmines and lasermines.

See also 
PackBot
Gladiator tactical unmanned ground vehicle

References
How stuff works

External links
 

Unmanned ground combat vehicles
Robots of the United States
Tracked robots
2003 robots
Lotus 91. The Lotus 91 was a car used by the English team Lotus in the 1982 Formula One season, designed by Colin Chapman, Martin Ogilvie and Tony Rudd.

Design 
After several uncompetitive seasons with experimental or uncompetitive cars, Colin Chapman went back to basics and designed the Lotus 91, based in part on the Williams FW07 and Lotus' own 88 design. Powered by the Ford Cosworth DFV and using a standard Hewland gearbox, the 91 was uncomplicated and easy to maintain. Following Brabham's lead, the new car was the first Lotus chassis to use carbon brakes, improving braking performance considerably.

After a design study by Chapman into new composite materials, the decision was taken to build the car in carbon fibre and Kevlar, making it, after the McLaren MP4/1 and Lotus 87, the third F1 car to race to be built from the material - the Lotus 88 not having raced before it was banned.

Under the direction of Peter Warr, the team worked hard to make the car as competitive as possible. The lightweight chassis gave the 91 a fighting chance against the far more powerful turbo engined cars and Cosworth worked on a short stroke version of the DFV purely for Lotus' use. The sidepods were full length units, extending to the very back of the car to take full advantage of the ground effect aerodynamics. However the 91 was quite pitch sensitive, making it tricky to drive. The Lotus 91 was the basis for the Lotus 92 - which pioneered active suspension in Formula 1. This suspension was revolutionary, using an on-board system to control the ride height and behaviour of the suspension, thus the Lotus 92 was the first car to be fitted with active suspension. The system was partially controlled by computers but at this early stage was mostly operated by hydro-pneumatic valves.

Racing history 
Elio de Angelis used the car well but found the 91 was mostly competitive on ultra fast tracks like Hockenheim, Monza and the Österreichring. The latter track provided a thrilling final lap win for de Angelis against Keke Rosberg in the Williams. That win, as well as several other consistent results by de Angelis and a podium place by Mansell, helped the team to fifth in the final standings in 1982, before ground effects were banned for the 1983 Formula One season and the 91 was replaced by the first Lotus turbo car.

The 91 was the last Lotus F1 car to win a race under Colin Chapman's rule before he died of a heart attack on 16 December 1982.

Complete Formula One results
(key)

References

91
ESW. ESW can mean:
 Engineers for a Sustainable World, a national not-for-profit based in Pittsburgh, Pennsylvania
 Empire State Wrestling, an independent wrestling promotion that has operated in Western New York State since 2002
 Embedded software, computer software that plays an integral role in the electronics it is supplied with
 Electroslag welding, a single pass welding process.
 esw, formerly EShopWorld, a software company owned by Asendia.
 Every Single Word, a YouTube channel and Tumblr blog dealing with POC representation in media
 Eswatini (FIFA and IOC code: ESW), southern African country formerly known as Swaziland
Great deluge algorithm. The Great deluge algorithm (GD) is a generic algorithm applied to optimization problems. It is similar in many ways to the hill-climbing and simulated annealing algorithms.

The name comes from the analogy that in a great deluge a person climbing a hill will try to move in any direction that does not get his/her feet wet in the hope of finding a way up as the water level rises.

In a typical implementation of the GD, the algorithm starts with a poor approximation, S, of the optimum solution. A numerical value called the badness is computed based on S and it measures how undesirable the initial approximation is. The higher the value of badness the more undesirable is the approximate solution. Another numerical value called the tolerance is calculated based on a number of factors, often including the initial badness.

A new approximate solution  S' , called a neighbour of S, is calculated based on S. The badness of  S' ,  b' , is computed and compared with the tolerance. If  b'  is better than tolerance, then the algorithm is recursively  restarted with S : =  S' , and tolerance := decay(tolerance) where decay is a function that lowers the tolerance (representing a rise in water levels). If  b'  is worse than tolerance, a different neighbour  S*  of S is chosen and the process repeated. If all the neighbours of S produce approximate solutions beyond tolerance, then the algorithm is terminated and S is put forward as the best approximate solution obtained.

See also
 de:Gunter Dueck

References
 Gunter Dueck: "New Optimization Heuristics: The Great Deluge Algorithm and the Record-to-Record Travel", Technical report, IBM Germany, Heidelberg Scientific Center, 1990.
 Gunter Dueck: "New Optimization Heuristics The Great Deluge Algorithm and the Record-to-Record Travel", Journal of Computational Physics, Volume 104, Issue 1, p. 86-92, 1993

Optimization algorithms and methods
Sydney Model Railway Exhibition. The Sydney Model Railway Exhibition is an annual railway modelling exhibition, which is held on the Labour Day long weekend in October in Sydney. It is organised by the New South Wales Branch of the Australian Model Railway Association (AMRA). 
 
The Exhibition was first held in 1962 in Burwood, and since then, the Exhibition has been held annually: first at Burwood at the Police-Citizens Boys Club, and then at the Lower Sydney Town Hall. In 1977 the Exhibition moved to the Ford and Mazda pavilions at the Sydney Showground (Moore Park), before moving to the Whitlam Centre in Liverpool in 1984. The Exhibition was held at the Hurstville Leisure and Aquatic Centre in 2005, when the Whitlam Centre at Liverpool was being renovated. The 2019 Exhibition is to be held, for the first time, at the Southee Pavilion at Sydney Olympic Park.

It includes various layouts and commercial stands of the following gauges:
 G scale
 O scale
 On30 scale
 00 scale
 HO Scale
 HOn3 1/2 scale
 HOn 2 1/2 scaleAustr
 N scale
 Z scale

The programme sponsors a vote of favourite layout, for which the winner receives a prize (usually, but not always, a train set). In the past, "The Train Shed" has operated a ride-on Thomas the Tank Engine for children at the show. Ride-on train rides are now operated by the North-West Model Engineers. There is also a "U-Drive" display that allows visitors to operate working scale models of Thomas the Tank Engine and Australian prototype trains.

In 2005, the Association moved the exhibition to the Hurstville leisure centre for 2005 and 2006 before returning to the Whitlam Centre from 2007 onwards. This model railway exhibition is one of the oldest and largest model railway exhibitions in Australia. In 2012 the Australian Model Railway Association celebrated the 50th anniversary of the Sydney Model Railway Exhibition.

In September 2023, the AMRA NSW Branch announced on Facebook that the 2019 exhibition ran at a loss, and COVID had prevented exhibitions in 2020 - 2022. AMRA NSW stated that it "is not currently in the position to host the Sydney Model Railway Exhibition, not in 2023, not in 2024, and not for the foreseeable future."

References

Exhibitions in Australia
Model railway shows and exhibitions
Recurring events established in 1962
1962 establishments in Australia
WACO Classic Aircraft. The WACO Classic Aircraft Corporation is an American aircraft manufacturer, located in Battle Creek, Michigan. It was founded in 1983 as the Classic Aircraft Corporation and is now called the WACO Aircraft Corporation.

WACO Classic Aircraft builds, in relatively small numbers, a three-seat biplane, the WACO Classic YMF, based upon the original manufacturing plans which were filed by the Waco Aircraft Company with the Library of Congress and thus available. The aircraft are constructed at the W. K. Kellogg Airport in Battle Creek, Michigan. The company also repairs original "classic" WACOs and vintage aircraft.

While the aircraft it builds is a longstanding design, WACO Classic Aircraft has upgraded many systems, such as the brakes, to newer and safer technology. They are built with much of the original hand construction methods and are sought after as a classical open-cockpit aircraft, but with modern digital electronics. To date, Waco Classic only offers one of several models of Wacos that were built. Over 100 new YMF-5C aircraft had been completed by 2007.

In June 2009, the company announced the improved YMF-5D version, powered by a Jacobs R-755-A2  engine. The type was to be type certified in October 2009 and features a new MT-Propeller, a deluxe leather interior, new lightweight carbon fiber wheel pants and fairings, an upgraded avionics package and a cup holder.

In January 2011, the company announced that it would put the Great Lakes Model 2T-1A-1/2 biplane back into production. The aircraft had not been available since 1980. The aircraft incorporates several changes including a larger cockpit and advanced avionics. It is equipped with the Lycoming AEIO-360-B1F6 engine. In May 2012, the company announced that the first production Great Lakes was being constructed and it was completed in June 2013.

In November 2018, the company was acquired by the Florida-based Dimor Group Inc.

Aircraft
Great Lakes Sport Trainer
WACO Classic YMF

References

External links

Aircraft manufacturers of the United States
Companies based in Battle Creek, Michigan
Privately held companies based in Michigan
Yekaterinburg bridge collapse. In the Yekaterinburg bridge collapse in Russia, on September 6, 2006 (according to Itar-Tass) railway traffic was paralyzed by the collapse of an automobile bridge near the center of city.

Overview 

The head of the Sverdlovsk Railway, Shevket Shaidullin, said damage caused by the incident was “quite significant.”

“A total of 111 freight trains and 104 passenger trains were delayed. Changes to the train schedule incurred big costs,” he said.

He said, however, that the railway tracks had not been damaged.

Three of 10 reinforced-concrete beams of the bridge span above the railway fell onto the rail tracks.  Work to dismantle the other six remaining beams was conducted through the joint efforts of railwaymen and builders. The bridge beams were first separated from one another by slits and then lowered to the ground by means of emergency train jibs.

The automobile bridge that was under construction in the center of Yekaterinburg collapsed at the crossing of Shevchenko and Vostochnaya Streets on Monday afternoon.  Traffic along Vostochnaya Street that is one of the main highways of the city was blocked.  According to Sverdlovsk Railways, east- and west-bound train traffic through the Sverdlovsk junction station was also stopped.

City Mayor Arkady Mikhailovich Chernetsky said a gross design mistake might have caused the collapse of the bridge.

Causes 

“Possible causes may also include a mistake made by builders, but this is unlikely because the contractor is a very reliable company.  It is too early to make concrete conclusions. They will be made by a special commission,” Chernetsky said.

Federal court of the Kirovsky residential area of Yekaterinburg judged that Viktor Menshikov, director of a municipality "Blagoustroistvo" is responsible for bridge collapse. Bridge collapsed because construction works were conducted with a violation of a city-building codex. Also, director didn't send a bridge design documents for public examination and didn't receive an approval for construction of the bridge.

Casualties 

There were no casualties in the Yekaterinburg highway bridge collapse, but the incident halted west- and east-bound railroad traffic through the city, the information department of Russia's Emergencies Ministry told Itar-Tass.

Chernetsky said the bridge was supposed to become operational in November. He said the bridge would be built anyway because “this is an important element of transport infrastructure.”

See also 
 List of bridge disasters

References

Bridge disasters in Russia
Bridge disasters caused by construction error
Road incidents in Russia
Railway accidents and incidents in Russia
History of Yekaterinburg
2006 disasters in Russia
2006 road incidents
September 2006 events in Russia
2000s road incidents in Asia
Building and structure collapses in 2006