omniomni/omni-engineering huggingface dataset:
Chebyshev linkage. In kinematics, Chebyshev's linkage is a four-bar linkage that converts rotational motion to approximate linear motion.

It was invented by the 19th-century mathematician Pafnuty Chebyshev, who studied theoretical problems in kinematic mechanisms. One of the problems was the construction of a linkage that converts a rotary motion into an approximate straight-line motion (a straight line mechanism). This was also studied by James Watt in his improvements to the steam engine, which resulted in Watt's linkage.

Equations of motion 
The motion of the linkage can be constrained to an input angle that may be changed through velocities, forces, etc. The input angles can be either link L2 with the horizontal or link L4 with the horizontal. Regardless of the input angle, it is possible to compute the motion of two end-points for link L3 that we will name A and B, and the middle point.

 
 

while the motion of point B will be computed with the other angle,

 
 

And ultimately, we will write the output angle in terms of the input angle,

 

Consequently, we can write the motion of point P, using the two points defined above and the definition of the middle point.

Input angles 
The limits to the input angles, in both cases, are:

Usage 
Chebyshev linkages did not receive widespread usage in steam engines, but are commonly used as the 'Horse head' design of level luffing crane. In this application the approximate straight movement is translated away from the line's midpoint, but it is still essentially the same mechanism.

See also 

Chebyshev lambda linkage, the cognate of the Chebyshev linkage.
Four-bar linkage
Straight line mechanism

References

External links 

Cornell university, "How to draw a straight line, by A.B. Kempe, B.A."
A simulation  using the Molecular Workbench software
A Geogebra simulation of the linkage
A 3D video of the linkage

Linkages (mechanical)
Linear motion
Straight line mechanisms
Hoc (programming language). hoc, an acronym for High Order Calculator, is an interpreted programming language that was used in the 1984 book The Unix Programming Environment to demonstrate how to build interpreters using Yacc.

hoc was developed by Brian Kernighan and Rob Pike as a glorified interactive calculator. Its basic functionality is to evaluate floating-point numerical expressions, e.g., . Then, variables were added, conditionals, loops, user-defined functions, simple IO, and more, using a syntax resembling C.

An improved hoc interpreter was included in Eighth Edition Research Unix in 1985, but it has not been generally adopted by commercial Unix systems or by Linux distributions. Instead, the earlier calculator languages dc and bc have become widespread on those systems. hoc survived and continued to evolve as part of the Plan 9 operating system. Several improved versions of hoc were released as free software by Bell Labs and other individuals (see list below). hoc is used, alongside python, as a scripting language for the Neuron simulator.

Examples
The following is a simple example of an interactive calculator session in hoc;  text represents hoc's output:
 1+2*3
     7
 angle=PI/3
 r=sin(angle)
 r
     0.866025
 r*2
     1.73205
And a simple example of functions and flow control:
 func atan2(){
         if ($1>0){
                 return atan($2/$1)
         } else if ($1<0){
                 return atan($2/$1)+PI
         } else if ($2>0){
                 return PI/2
         } else if ($2<0){
                 return -PI/2
         } else {
                 print "atan2 domain error"
                 return 0
         }
 }
 
 atan2(2,3)
     0.982794
 atan2(0,0)
 atan2 domain error
     0.0

References

External links

hoc implementations and versions
 AT&T versions:
 The original code from the Unix Programming Environment book, including hoc.
 Source code of hoc from Bell Labs, released as free software. This is the Research Unix version, slightly improved over the one in the book.
 Plan9 version of hoc released under the MIT License. This version is slightly different from the Research Unix version, with the most notable difference being that numbered function arguments ($1, $2, etc., as in the Unix shell) were replaced by named arguments (as in C). See also Plan 9's hoc manual.
 Other versions:
 an extended version of hoc by Nelson H. F. Beebe.
 an extended version of hoc by Nadav Y. Har'El.
 an extended version of hoc by Jack Dennon.
 an extended version of hoc by Michael Hines, John W. Moore, and Ted Carnevale.

Software calculators
Free mathematics software
Numerical programming languages
Unix programming tools
Plan 9 commands
Stadtbahnwagen B. The Stadtbahnwagen Typ B (translation Type "B" Light Rail Vehicle, short form B-Wagen) is a light rail vehicle used by several Stadtbahn networks in the German state of North Rhine-Westphalia as well as by the Bursaray network in Bursa, Turkey. It was mainly developed by Düsseldorf-based Duewag, who also built the majority of vehicles in a consortium with Siemens and Kiepe. A small series of ten units was built by Waggon Union in Berlin.

As the type evolved over two decades of production, some vehicles have little more in common than their outer dimensions and the basic configuration of a two-part multiple unit on three bogies with both outer ones powered. For the Dortmund Stadtbahn, some cars were modified with a central section and a fourth bogie. These vehicles are referred to as B8 or  B80C/8 (eight axles). These vehicles have a length of  and a weight of .

History 
When the Rhine-Ruhr Stadtbahn network was planned in the early 1970s, standardised rolling stock was planned as well. At the same time, a second Stadtbahn network was planned for Cologne and Bonn. Because the future Cologne Stadtbahn already had one finished tunnel, that was built with the city's own money with streetcars in mind, the Stadtbahnwagen designed for the Rhine-Ruhr network was not suitable. So, another vehicle was designed for the Cologne/Bonn network, that was capable of driving though tighter curves.

This vehicle, now referred to as Stadtbahnwagen Typ B was immediately ordered by transport authorities in Cologne and Bonn, while Rhine-Ruhr authorities remained hesitant about "their" vehicle, now renamed Stadtbahnwagen Typ A. Eventually it was decided that the type "A" LRV was too unwieldy and type "B" LRVs were ordered by Essen, Mülheim, Düsseldorf, Duisburg, Dortmund and Bochum. The type "A" concept, which consists of close coupled two-car sets, was shelved and later revived for the Stuttgart Stadtbahn.

The Typ B formed the basis for the British-built Metrocars on the Tyne and Wear Metro, which opened in 1980. It was adapted for the Americas and sold under de Siemens brand as the SD SD-400/460 from 1985 onwards. The Typ B also formed the basis for the vehicles used on the Docklands Light Railway (DLR), which opened in 1987.

Subtypes 
Different variants are usually referred to by a combination of their top speed and a letter denoting the engine type.

References

Light rail vehicles
Duewag tram vehicles
Tram vehicles of Germany
Electric multiple units of Germany
750 V DC multiple units
Butterworth Westland Whirlwind. 

The Butterworth Westland Whirlwind was a 2/3 scale flying replica of the British Westland Whirlwind fighter aircraft of World War II that was built in the United States in the 1970s. The aircraft was based on the wings and horizontal tail of a Grumman American AA-1A modified and mated to an all-new fuselage. Power was provided by two Volkswagen air-cooled horizontally opposed four-cylinder engines with the result bearing only a passing resemblance to the real Whirlwind. Butterworth marketed plans in the late 1970s and early '80s, with at least 15 sets selling and at least three aircraft reportedly under construction by 1985.

Specifications

References
 
 
 

1970s United States sport aircraft
Homebuilt aircraft
Replica aircraft
Low-wing aircraft
Aircraft first flown in 1977
Twin piston-engined tractor aircraft
MeshBox. MeshBox is an item of computer hardware which is used to provide large scale wireless broadband networks. Manufactured by LocustWorld, the devices are designed to co-operate with other MeshBoxes within range, passing the internet service from one box to the next, over the air, until it reaches the final destination. The coverage area of a mesh is typically measured in square miles or square kilometres.

Originally released as a bootable CD-ROM called MeshAP based on the OpenAP open source software, the system is now implemented as system image which can fit within a small 32MB CompactFlash card. The system functions have expanded beyond creating wireless networks to provide set-top box services, MP3 audio and video streaming, connection to remote windows terminal servers, other PCs, web browsing, connection to peer-to-peer networks, instant messaging and file exchange.

See also
 Wireless mesh network
 Wireless LAN
 Wireless access point
 Wireless community network
 IEEE 802.11

External links
 CommunityWireless.org
 Wireless Internet Assigned Numbers Authority

Hardware routers
Linux-based devices
IEEE 802.11
Mesh networking
Mustang Aeronautics Midget Mustang. The Mustang Aeronautics Midget Mustang MM-1 is a single-seat aerobatic sports airplane developed and marketed in the United States for homebuilding. It is also known as the Long Midget. It was the predecessor to the Mustang II which is also known as the Bushby Mustang. Rights to both the Midget Mustang and the Mustang II were sold to Mustang Aeronautics in 1992.

Development
It is a low-wing cantilever monoplane of metal construction, primarily of 2024-T3 aluminum and most are fitted with fixed tailwheel undercarriage.  Developed by Piper engineer David Long in 1948, plans for production by Schweizer were underway at the time of Long's death two years later.  All rights and tooling were purchased by Robert Bushby in 1959, who built a 90 hp Continental powered example and sold plans and kits until 1992  when the rights were sold to Mustang Aeronautics. The Midget Mustang design being marketed in 2016 is similar to the original, with the option of building it with a bubble canopy in place of the straight line of the upper tailcone and hinged canopy of Long's original design, making it an M-IA.

Construction requires about 1000 hours of builder time.

Operational history
The Midget Mustang was intended for air racing. David Long designed an aircraft for a friend to be used in the Cleveland Air Race in 1948.  That aircraft was built by Long and was named "Pea Shooter".  The Midget Mustang was only moderately successful as a race plane.  However, its appearance and desirable flight characteristics made it an ideal sport plane. At the Cleveland Race, racers competed in aircraft with names like, "Mammy","Miss Fort Worth", and "Slo Poke". Over time, air racers modified the aircraft to reach 181 mph (291 km/h) speeds in competition. Nowadays, the Midget Mustang can cruise at 240 mph.

Variants
Midget Mustang
"GG"
A tricycle gear modification
Graham Super Midget
Features a manually retracted landing gear.

Specifications (MM-1-125)

See also

References

External links

 Manufacturer's website

1940s United States sport aircraft
Homebuilt aircraft
Midget Mustang
Low-wing aircraft
Single-engined tractor aircraft
Aerobatic aircraft
Aircraft first flown in 1948
Single-engined piston aircraft
Aircraft with fixed conventional landing gear
Programmable sound generator. A programmable sound generator (PSG) is a sound chip that generates (or synthesizes) audio wave signals built from one or more basic waveforms, and often some kind of noise. PSGs use a relatively simple method of creating sound compared to other methods such as frequency modulation synthesis or pulse-code modulation.

Technical details 
PSGs are controlled by writing data to dedicated registers on the chip via an external CPU; hence the name programmable sound generator. One or more basic waveforms are generated (typically a square, triangle or saw-tooth wave) and often a noise signal. The waveforms' frequency and volume (and noise's tone and volume) are typically shaped using an envelope and/or mixed before being sent to the audio output stage.

Many PSGs feature three tone channels and one noise channel including the AY-3-8910, SN76489 and MOS Technology 6581.

History 
In the late 1970s, more electronic consumer devices began to be designed with audio features. PSGs were partly developed as a way of incorporating relatively complex sounds at a low cost. PSGs were in many arcade games, game consoles, and home computers of the 1980s and 90s.

In 1978, General Instrument released the AY-3-8910, the design of which was later licensed by Yamaha Corporation for their YM2149. These chips were used as the standard for the MSX computer standards 1 and 2, respectively. The features of this chip were also incorporated into other Yamaha sound chips including the YM2203 and YM2608 chips, these were also capable of FM synthesis. In the same year Atari designed the POKEY chip for its home computers and game systems. It incorporated a PSG.

In 1979, Texas Instruments SN76489 was produced for the TI-99/4 computer. This was also used in the Tandy 1000 and IBM PCjr.

In 1982, MOS Technology 6581 was produced for the Commodore 64. The main chip in the Nintendo Entertainment System, the Ricoh 2A03, included a PSG.

List of PSGs

See also 
List of sound card standards
List of Yamaha sound chips

References

Sound chips
Brazilian Telecommunications Society. The Brazilian Telecommunications Society () is a scientific academy of Brazil. Created in 1983 with no competing financial interest, it is devoted to promoting the diffusion, the development and the interchange of ideas and results in the field of Telecommunications. The SBrT is co-sister society of the IEEE Communications Society. The meetings and conferences sponsored by SBrT are now a forum for scientific, technological debate.

The SBrT holds an annual scientific congress, the Brazilian Telecommunication Symposium (Simpósio Brasileiro de Telecomunicações), and each four years, the International Telecommunication Symposium – ITS (joint with IEEE).

It publishes the scientific journal – The Journal of Communication and Information Systems (JCIS), co-sponsored by the IEEE Communications Society. The SBrT also publishes the  «Série Brasport», a series of textbooks on Telecommunications and correlated fields.

External links
 http://www.sbrt.org.br/  Society homepage (Portuguese)
 https://web.archive.org/web/20150623063854/http://www6.fee.unicamp.br/ojs/index.php/JCIS Journal of Communication and Information Systems
 https://web.archive.org/web/20070809081358/http://iecom.dee.ufcg.edu.br/~jcis/  Journal of Communication and Information Systems (old issues)

See also
 Brazilian science and technology

Scientific societies based in Brazil
Telecommunications in Brazil
Microsoft Network Monitor. Microsoft Network Monitor (Netmon) is a deprecated packet analyzer. It enables capturing, viewing, and analyzing network data and deciphering network protocols. It can be used to troubleshoot network problems and applications on the network. Microsoft Network Monitor 1.0 (codenamed Bloodhound) was originally designed and developed by Raymond Patch, a transport protocol and network adapter device driver engineer on the Microsoft LAN Manager development team.

Network Monitor was replaced by Microsoft Message Analyzer (MMA was discontinued in 2019).

History 
The LAN Manager development team had one shared hardware-based analyzer at the time. Netmon was conceived when the hardware analyzer was taken during a test to reproduce a networking bug, and the first Windows prototype was coded over the Christmas holiday. The first 4 bytes of the Netmon capture file format were used to validate the file. The values were 'RTSS' for Ray, Tom, Steve, and Steve - the first four members of the team. The code was originally written for OS/2 and had no user interface; a symbol was placed in the device driver where the packet buffers were kept so received data could be dumped in hex from within the kernel debugger.

Netmon caused a bit of a stir for Microsoft IT since networks and e-mail were not encrypted at the time. Only a few software engineers had access to hardware analyzers due to their cost, but with Netmon many engineers around the company had access to network traffic for free. At the request of Microsoft IT, two simple identification features were added - a non-cryptographic password and an identification protocol named the Bloodhound-Oriented Network Entity (BONE) (created and named by Raymond Patch as a play on the codename Bloodhound).

Network Monitor 3 is a complete overhaul of the earlier Network Monitor 2.x version.  Originally, versions of Network Monitor were only available through other Microsoft products, such as Systems Management Server (SMS).  But now the fully featured product with public parsers is available as a free download.

Microsoft Network Monitor was superseded by Microsoft Message Analyzer (discontinued in 2019).

Features 
Some key features of Network Monitor 3.4 include the following:
Process tracking
Grouping by network conversation
Support for over 300 public and Microsoft proprietary protocols
Simultaneous capture sessions   
Wireless Monitor Mode with supported wireless NICs
Real-time capture and display of frames 
Reassembly of fragmented data
Sniffing of promiscuous mode traffic
Can read libpcap capture files
API to access capture and parsing engine

References

External links 
 Microsoft Network Monitor:
 Download 3.4 (archive)
 (Download) Windows and SQL Server Network Monitor Parsers
 Blog
 Forum Support for 3
 
 Experts at CodePlex
 Open Source Parsers at CodePlex
 

 Microsoft Message Analyzer:
 Download 1.1
 
 
 Forum Support for 1.1
 Message Analyzer (Network Monitor's successor) on Microsoft Connect

 Windows Protocol Test Suites 1.0 on GitHub

Network Monitor
Network analyzers
Windows network-related software
Edward E. Hammer. Edward E. Hammer (December 27, 1931 – July 16, 2012) was an engineer who was at the forefront of fluorescent lighting research. His technological contributions in incandescent, fluorescent and HID light sources earned him over 35 patents.

He received his bachelor's degree from Manhattan College in 1954.

During the energy crisis of the 1970s, he led the development of General Electric’s pioneering energy-efficient lamp.  He led the development of the Watt Miser (marketed as the F-40 Watt Miser), which was released in 1973. In 1976, he invented the first compact fluorescent lightbulb, but due to the difficulty of the manufacturing process for coating the interior of the spiral glass tube, GE did not manufacture or sell the device. Other companies began manufacturing and selling the device in 1995.  The Smithsonian Institution houses Hammer's original CFL prototype.

Hammer is an IEEE Fellow and the 2002 IEEE Edison Medal winner.

References

External links
 Edward E. Hammer - Inventor of the Compact Helical Fluorescent Lamp.

1931 births
2012 deaths
Engineers from Brooklyn
Manhattan College alumni
American electrical engineers
IEEE Edison Medal recipients
Wright Gemini. Wright Gemini, a generic name for a style of low-floor double-deck bus bodywork built by Wright may refer to:

 Wright Eclipse Gemini, on Volvo-based chassis
 Wright Gemini 2 DL, an integral double-decker with VDL chassis modules
 Wright Gemini 2 HEV, an integral hybrid double-decker
 Wright Pulsar Gemini, on VDL DB250 chassis
Nanochondrion. Nanochondria are hypothetical nanomachines that are meant to live inside or with biological cells. They are named after mitochondria, due to their similarities in working inside the cell, and their reproduction.

Abilities
Nanochondria would be able to replicate themselves within the body, even to the point where a mother would pass them on to her children, reducing the need for them to be implanted after the first generation. Even a single nanochondrion inside of an egg cell would be able to replicate to the point where the person that was born from the egg would have nanochondria in every cell in their body.  They would interact with and modify cells in the body,  potentially allowing people to modify or even make copies of themselves. Due to this, they have been criticized for their ability to make synthetic humans, or even "natural robots", as well as their potential to damage DNA. Nanochondria would even allow a person to exhale a utility fog, allowing them to in effect "breathe" a needed tool.

Nanochondria would have to be incredibly small, which would limit their computational power. To remedy this, they would be likely be able to communicate with each other, as well as other devices inside and outside the body, in an internalnet, in a distributed computing network. This would be likely to be accomplished by acoustic wave communication, or using wires composed of single electrons. Anders Sandberg has commented saying that "mitochondria ... just react on local conditions and indirectly cooperate". and that "It might be hard to make those pipes reliable", although he conceded that  "linked nanochondria will be much more versatile". Nanochondria could be used to perform a diagnostic test on a person's own body, and then used to fix or even modify cells.

See also
 Cyborg 
 Implications of nanotechnology
 Nanomedicine

References

Nanotechnology
Nanomachines
Conductive textile. A conductive textile is a fabric which can conduct electricity. Conductive textiles  known as lamé are made with guipé thread or yarn that is conductive because it is composed of  metallic fibers wrapped around a non-metallic core or has a metallic coating.  A different way of achieving conductivity is to weave metallic strands into the textile.

Some historic fabrics use yarns of solid metals, most commonly gold. Alternatively, novel materials such as nanomaterials (including graphene, and carbon nanotubes) or conducting polymers may also be used as the conducting materials. There is also an interest in semiconducting textiles, made by impregnating normal textiles with carbon- or metal-based powders.

Conductive fibers consist of a non-conductive or less conductive substrate, which is then either coated or embedded with electrically conductive elements, often carbon, nickel, copper, gold, silver, titanium or PEDOT. Metals may be deposited chemically with autocatalytic chemistry, printed with conductive nanoparticle inks, or applied with physical vapor deposition methods. Substrates typically include cotton, polyester, nylon, and stainless steel to high performance fibers such as aramids and PBO.  Straddling the worlds of textiles and wires, conductive fibers are sold either by weight or length, and measured in denier or AWG.

Because of the rapid growth in the kinds of conductive fibers and the uses of these fibers, a trade association—the Conductive Fiber Manufacturers Council—was formed to increase awareness, utilization, and possibly standardize terminology.

Applications

Uses for conductive fibers and textiles may include static dissipation, EMI shielding, signal and power transfer in low resistance versions, and as a heating element in higher resistance versions.  Their benefits over solid or stranded metal wires come from conductive fibers' flexibility and ability to use them in existing textile and wire machinery (weaving, knitting, braiding, etc.).

The sport of fencing employs lamés, jackets made of conductive textiles, to detect hits in competitions.

One major use is by Micro Coax's ARACON fiber built on a KEVLAR base, and used for shielding cabling in air- and spacecraft and other speciality purposes where light weight, high strength, and high-frequency shielding is imperative. Another more recent use is in the production of 'stun gun' or Taser-proof clothing, where the conductive textile forms a flexible Faraday cage in a layer of the garment. Conductive fabric can also be used to make electrodes for  EEG and other medical applications; such electrodes were used in a commercially available sleep-monitoring device made by former company Zeo, Inc. Highly conductive stainless steel fiber is available.

See also
 Faraday cage
 E-textiles
 Cloth of Gold

References

Technical fabrics
Electrostatics