omniomni/omni-engineering huggingface dataset:
Martin XB-68. The Martin XB-68 was a supersonic medium tactical bomber with a crew of two that was proposed in 1954 to the United States Air Force. The project, however, was canceled before any aircraft were built.

Design and development
The Glenn L. Martin Company submitted design studies in response to the Weapon System 302A requirement in 1952 in competition with proposals from Douglas Aircraft Company and North American Aviation, Inc. Revised designs were presented again in 1954. The Boeing Airplane Company also submitted a design after the competition date had passed and was automatically rejected. The Martin 316 was declared the winner in 1956 and received the designation XB-68. Deployment was projected for the 1962-1965 period.

With a conventional layout that somewhat resembled a scaled-up Lockheed F-104, the XB-68 was to have been primarily of steel construction, with the crew of a pilot-radio operator and navigator-bombardier defense systems operator in a pressurized compartment, to be cooled by filtered bleed-air from the engines, and a refrigeration unit for evaporative cooling at high Mach numbers. The B-68 would have had stubby diamond-shaped wings and a raked T-tail empennage. It was intended to be operated at supersonic speeds at medium and high altitudes.

The design immediately ran into serious difficulties over the inertial guidance bombing and navigation system, which, had the bomber been approved for production, would have pushed deployment back to at least 1963. The problems were rendered moot when Air Force headquarters cancelled the project in 1957, citing stringent budget limitations and higher priorities for other weapon systems. Recognizing that the medium tactical bomber design was still years away, plans were carried forward instead to continue using an Air Force version of the Navy's Douglas A3D, which was designated B-66 Destroyer. Two planned XB-68 prototypes and one static test model were cancelled, and none were built.

The chosen power plant was two Pratt & Whitney J75 (JT4B-21) axial-flow turbojets of  static sea level thrust each with afterburner, providing a maximum speed of  at  altitude at maximum power and a combat speed of  at  altitude at maximum power. Combat range was planned for  with  payload at  average speed in 4.15 hours.

Specifications (as designed)

See also

References

External links

 Aerospace Review: Martin XB-68
 Defense Talk: XB-68
 The Unwanted Blog: Martin XB-68, Martin Model 316, Model 302 drawings

Martin aircraft
Twinjets
Cancelled military aircraft projects of the United States
1950s United States bomber aircraft
Mid-wing aircraft
T-tail aircraft
Aircraft with retractable bicycle landing gear
Gelcoat. Gelcoat or gel coat is a material used to provide a high-quality finish on the visible surface of a fibre-reinforced composite. The most common gelcoats are thermosetting polymers based on epoxy or unsaturated polyester resin chemistry. Gelcoats are modified resins which are applied to moulds in the liquid state. They are cured to form crosslinked polymers and are subsequently backed with thermoset polymer matrix composites which are often mixtures of polyester resin and fiberglass, or epoxy resin which is most commonly used with carbon fibre for higher specific strength. 

The manufactured component, when sufficiently cured and removed from the mould, presents the gelcoated surface. This is usually pigmented to provide a coloured, glossy surface which improves the aesthetic appearance of the article, such as the surface of a boat hull. 

Many marine craft and some aircraft are manufactured using composite materials with an outer layer of gelcoat, typically 0.5 mm to 0.8 mm (0.02 in to 0.03 in) thick. Gelcoats are designed to be durable, providing resistance to ultraviolet degradation and hydrolysis. 

Specialized gelcoats can be used to manufacture the moulds which in turn are used to manufacture components. These require very high levels of durability to overcome the mechanical and thermal stresses encountered during the curing and demoulding processes. Most fiberglass molds have non-conductive tooling gelcoats that accumulate static electricity, resulting in safety risks and difficulties in handling. Advancements in conductive tooling gelcoates with single wall carbon nanotubes (SWCNTs) make molds safer and easier to use by reducing dust attraction, combating electric shocks to workers, and eliminating issues with de-molding.   

Suitable resin chemistries for the manufacture of gelcoats vary, but the most commonly encountered are unsaturated polyesters or epoxies. Within each of these categories, the resin chemistries are further subdivided.

In addition to any pigment, if necessary a gelcoat will contain a thixotropic additive to assist its tenacity to vertical portions of the mould whilst it cures.

Sources

 
 

Composite materials
Non-Linear Systems. Non-Linear Systems is an electronics manufacturing company based in San Diego, California. Non-Linear Systems was founded in 1952, by Andrew Kay, the inventor of the digital voltmeter in 1954.

NLS developed a reputation for providing rugged durability in critical applications for everything from submarines to spacecraft.

Later the company developed miniature digital voltmeters and frequency counters. During the early 1980s the company started Kaypro, which developed an early personal computer.

References

 Patents assigned to NLS

External links

Electronics companies established in 1952
Electronics companies of the United States
Manufacturing companies based in California
1952 establishments in California
Long-Term Mine Reconnaissance System. The AN/BLQ-11 autonomous unmanned undersea vehicle (formerly the Long-Term Mine Reconnaissance System (LMRS)) is a torpedo tube-launched and tube-recovered underwater search and survey unmanned undersea vehicle (UUV) capable of performing autonomous minefield reconnaissance as much as  in advance of a host -, -, or -class submarine.

LMRS is equipped with both forward-looking sonar and side-scan synthetic aperture sonar.

Boeing concluded the detailed design phase of the development project on 31 August 1999.
In January 2006,  successfully demonstrated homing and docking of an LMRS UUV system during at-sea testing.

History 
The USS Oklahoma City successfully launched the 8 m (20 ft) long vehicle for covert mine countermeasures in September 2005. The USS Scranton conducted 24 test runs in January 2006. In October 2007, USS Hartford conducted further tests.

The U.S. Navy's Mission Reconfigurable UUV System (MRUUVS) program, of which AN/BLQ-11 was a part, ended in December 2008 due to technical and engineering limitations.

Citations

Sources

Equipment of the United States Navy
Autonomous underwater vehicles
Consolidated XB-41 Liberator. The Consolidated XB-41 Liberator was a single Consolidated B-24D Liberator bomber, serial 41-11822, which was modified for the long-range escort role for U.S. Eighth Air Force bombing missions over Europe during World War II.

Design and development
When the USAAF started strategic bombing in Europe there were no fighters available to escort the bombers all the way to distant targets. The bombers carried several defensive guns and formed up in boxes so that they could provide mutually covering fire but there was interest in providing more firepower for the formation.
The XB-41 Liberator was outfitted with 14 .50 caliber (12.7 mm) machine guns. This was achieved by adding a second dorsal turret and a remotely operated Bendix turret (of the same type as fitted to the YB-40) under the chin to the standard twin gun tail turret and twin gun retractable ventral ball turret, plus twin mount guns at each waist window. The port waist mount was originally covered by a Plexiglas bubble; testing showed this caused severe optical distortion and it was removed.

The XB-41 carried 12,420 rounds of ammunition, 4,000 rounds of which were stored in the bomb bay as a reserve. It was powered by four  Pratt & Whitney R-1830-43 radial engines.

Operational history
On 29 January 1943, the sole XB-41 was delivered to Eglin Field, Florida. Tests were carried out for two months at Eglin during February 1943. These indicated significant problems with the aircraft; on 21 March 1943, the Army declared the XB-41 as unsuitable for operational use; the conversion of thirteen Liberators to YB-41 service test aircraft was cancelled. Despite this, Consolidated continued to work on the XB-41 prototype; wide-blade propellers were fitted, and some of the armor was removed to reduce the aircraft's weight. Tests resumed at Eglin on 28 July 1943; however, the basic flaws of the "gunship" concept remained, and the XB-41 program was abandoned. The prototype XB-41 was redesignated TB-24D; it served as an instructional airframe for training mechanics on the B-24. It was scrapped at Maxwell Field, Alabama on 2 February 1945.

Specifications (XB-41)

See also

References
Notes

Bibliography

 Andrade, John M. U.S. Military Aircraft Designations and Serials since 1909. Earl Shilton, Leicester: Midland Counties Publications, 1979. . 
 Birdsall, Steve. Log Of The Liberators. Garden City, New York: Doubleday and Company, 1973. .
 Davis, Larry. B-24 Liberator in action. Aircraft in Action No. 80. Carrollton, Texas: Squadron/Signal Publications, 1987. .

B-41
Consolidated B-41 Liberator
1940s United States fighter aircraft
Four-engined tractor aircraft
High-wing aircraft
Four-engined piston aircraft
Aircraft with retractable tricycle landing gear
Twin-tail aircraft
Dimethylethanolamine. Dimethylethanolamine (DMAE or DMEA) is an organic compound with the formula . It is bifunctional, containing both a tertiary amine and primary alcohol functional groups. It is a colorless viscous liquid. It is used in skin care products for improving skin tone and 
also taken orally as a nootropic.  It is prepared by the ethoxylation of dimethylamine.

Industrial uses

Dimethylaminoethanol is used as a curing agent for polyurethanes and epoxy resins. It is a precursor to other chemicals, such as the nitrogen mustard 2-dimethylaminoethyl chloride. The acrylate ester, dimethylaminoethyl acrylate is used as a flocculating agent.

Related compounds are used in gas purification, e.g. removal of hydrogen sulfide from sour gas streams.

Human uses
The bitartrate salt of DMAE, i.e. N,N-dimethylethanolamine bitartrate, is sold as a dietary supplement. It is a white powder providing 37% DMAE.

Animal tests show possible benefit for improving spatial memory and working memory.

See also
 Choline
 Diphenhydramine
 Doxylamine
 Ethanolamine
 Meclofenoxate (Centrophenoxine)
 Orphenadrine

References

Dimethylamino compounds
Primary alcohols
Cholinergics
Nootropics
Corrosion inhibitors
Ethanolamines
Arbitrated loop. The arbitrated loop, also known as FC-AL, is a Fibre Channel topology in which devices are connected in a one-way loop fashion in a ring topology. Historically it was a lower-cost alternative to a  fabric topology. It allowed connection of many servers and computer storage devices without using then very costly Fibre Channel switches.  The cost of the switches dropped considerably, so by 2007, FC-AL had become rare in server-to-storage communication. It is however still common within storage systems.

 It is a serial architecture that can be used as the transport layer in a SCSI network, with up to 127 devices.  The loop may connect into a fibre channel fabric via one of its ports.
 The bandwidth on the loop is shared among all ports.
 Only two ports may communicate at a time on the loop.  One port wins arbitration and may open one other port in either half or full duplex mode.
 A loop with two ports is valid and has the same physical topology as point-to-point, but still acts as a loop protocol-wise.
 Fibre Channel ports capable of arbitrated loop communication are NL_port (node loop port) and FL_port (fabric loop port), collectively referred to as the L_ports.  The ports may attach to each other via a hub, with cables running from the hub to the ports.  The physical connectors on the hub are not ports in terms of the protocol.  A hub does not contain ports.
 An arbitrated loop with no fabric port (with only NL_ports) is a private loop.
 An arbitrated loop connected to a fabric (through an FL_port) is a public loop.
 An NL_Port must provide fabric logon (FLOGI) and name registration facilities to initiate communication with other node through the fabric (to be an initiator).

Arbitrated loop can be physically cabled in a ring fashion or using a hub. The physical ring ceases to work if one of the devices in the chain fails. The hub on the other hand, while maintaining a logical ring, allows a star topology on the cable level. Each receive port on the hub is simply passed to next active transmit port, bypassing any inactive or failed ports.

Fibre Channel hubs therefore have another function: They provide bypass circuits that
prevent the loop from breaking if one device fails or is removed. If a device is removed
from a loop (for example, by pulling its interconnect plug), the hub’s bypass circuit
detects the absence of signal and immediately begins to route incoming data directly
to the loop’s next port, bypassing the missing device entirely. This gives loops at least
a measure of resiliency—failure of one device in a loop doesn’t cause the entire loop
to become inoperable.

See also
Storage area network
Fibre Channel
Switched fabric
List of Fibre Channel standards

References 

Fibre Channel
Network topology
Switched fabric. Switched fabric or switching fabric is a network topology in which network nodes interconnect via one or more network switches (particularly crossbar switches). Because a switched fabric network spreads network traffic across multiple physical links, it yields higher total throughput than broadcast networks, such as the early 10BASE5 version of Ethernet and most wireless networks such as Wi-Fi.

The generation of high-speed serial data interconnects that appeared in 2001–2004 which provided point-to-point connectivity between processor and peripheral devices are sometimes referred to as fabrics; however, they lack features such as a message-passing protocol. For example, HyperTransport, the computer processor interconnect technology, continues to maintain a processor bus focus even after adopting a higher speed physical layer. Similarly, PCI Express is just a serial version of PCI; it adheres to PCI's host/peripheral load/store direct memory access (DMA)-based architecture on top of a serial physical and link layer.

Fibre Channel 

In the Fibre Channel Switched Fabric (FC-SW-6) topology, devices are connected to each other through one or more Fibre Channel switches. While this topology has the best scalability of the three FC topologies (the other two are Arbitrated Loop and point-to-point), it is the only one requiring switches, which are costly hardware devices.

Visibility among devices (called nodes) in a fabric is typically controlled with Fibre Channel zoning.

Multiple switches in a fabric usually form a mesh network, with devices being on the "edges" ("leaves") of the mesh. Most Fibre Channel network designs employ two separate fabrics for redundancy. The two fabrics share the edge nodes (devices), but are otherwise unconnected. One of the advantages of such setup is capability of failover, meaning that in case one link breaks or a fabric goes out of order, datagrams can be sent via the second fabric.

The fabric topology allows the connection of up to the theoretical maximum of  about 16 million devices, limited only by the available address space (224).

239 domains * 256 areas * 256 ports = 15,663,104

See also 
 Clos network
 Fabric Application Interface Standard
 InfiniBand
 Network traffic control
 RapidIO
 VPX

References

External links 
 What is a Switch Fabric

Fibre Channel
Network topology
Adsorption Method for Sampling of Dioxins and Furans. Adsorption Method for Sampling of Dioxins and Furans (AMESA) is an automatic system for continuous monitoring of emissions of dioxins and furans from industrial processes which require official approval in compliance with environmental regulations. Applications include refuse incinerators and hazardous material incinerators.

Method
A sample is continuously extracted from the gas stream being monitored using a titanium probe, which is water-cooled to below 70 °C (why?). The sample flow rate is automatically adjusted to ensure isokinetic sampling (the velocity of gas entering the sampling system is equal to the velocity of the gas in the system under test). The sample gas is drawn through a quartz wool pre-filter and then across a cartridge filled with resin, such as XAD 2. The sample gas is also cooled to below 5 °C to condense and remove water vapour. All system parameters are recorded digitally during sampling. The resin cartridge and the condensate are removed at the end of a monitoring period, and the contents are analysed to determine levels of dioxins and furans.

References

Chemical tests
Analytical chemistry
Structure of Management Information. In computing, the Structure of Management Information (SMI), an adapted subset of ASN.1, is a technical language used in definitions of Simple Network Management Protocol (SNMP) and its extensions to define sets ("modules") of related managed objects in a Management Information Base (MIB).

SMI subdivides into three parts:  module definitions, object definitions, and notification definitions.

 Module definitions are used when describing information modules. An ASN .1 macro, MODULE-IDENTITY, is used to concisely convey the semantics of an information module.
  Object definitions describe managed objects.  An ASN.1 macro, OBJECT-TYPE, is used to concisely convey the syntax and semantics of a managed object.
  Notification definitions (aka "traps") are used when describing unsolicited transmissions of management information.  An ASN.1 macro, NOTIFICATION-TYPE, concisely conveys the syntax and semantics of a notification.

Implementations 

 libsmi, a C library for accessing MIB information

References

External links 
 , Standard 58, Conformance Statements for SMIv2
 , Standard 58, Textual Conventions for SMIv2
 , Standard 58, Structure of Management Information Version 2 (SMIv2)

Network management
Data modeling
ASN.1
ENAP. ENAP may refer to:

 École nationale d'administration publique, school of public administration in Quebec, Canada
 Empresa Nacional del Petróleo, Chilean oil company
 Escuela Nacional de Artes Plásticas, art school of the National Autonomous University of Mexico
 Escuela Nacional de Artes Plásticas "Rafael Rodríguez Padilla", art school in Guatemala City, Guatemala
 Ethylnaphthylaminopropane, a partial monoamine releasing agent
DEKA (company). DEKA Research & Development Corporation is a technology company based in New Hampshire, U.S., founded in 1982 by Dean Kamen, consisting of over 1000 engineers, technicians, and support staff. DEKA is an acronym derived from Dean Kamen. The company is located in a series of old Amoskeag Falls Millyard buildings in Manchester, New Hampshire; Kamen has real estate investments in the neighborhood beyond DEKA offices, contributing to revitalization of the neighborhood along with other major investors.

Products
IBOT wheelchair, licensed to Johnson & Johnson
The HomeChoice, Amia, and Kaguya families of portable dialysis machine, licensed to Baxter Healthcare
Stirling engine technologies
Stent
Segway, a personal transporter
Therakos
Slingshot, portable water purification system
Luke Arm, a DARPA project
Silicone Ankle Foot Orthosis (SAFO) and FLO-TECH APOPPS, adjustable postoperative protective and preparatory systems to protect injuries during early rehabilitation, both spun off to Next Step Orthotics & Prosthetics, Inc.
 Microdispensing contractor for the development of Coca Cola Freestyle.

Electric vehicles
Dean Kamen has developed a series plug-in hybrid car using a Ford Think and a Stirling engine. DEKA has shown off its new electric car, the DEKA Revolt, a two-seat hatchback that can achieve a range of about  on a single charge of its lithium battery. The Stirling engine is used for cabin heat, windshield defrosting and battery recharging.

Stirling engines can use any fuel and are affordable for the average consumer.

Kamen's team has also folded it into a hybridized Th!nk City as the on-board generator for the electric drive system.

In 2009, development of the two-wheeled Personal Urban Mobility and Accessibility (PUMA) vehicle was announced in cooperation with General Motors.

Awards and philanthropy
Dean Kamen was awarded the National Medal of Technology in 2000 by then President Clinton for inventions that have advanced medical care worldwide.

In 2003, his "Project Slingshot", a cheap portable water purification system, was named a runner-up for coolest invention of 2003 by Time magazine. Dean Kamen appeared on The Colbert Report showing off his water purifier by dumping Doritos into a red liquid, and having it purify the red liquid into a clear colorless pure water.

DEKA is a major sponsor and strategic partner of FIRST, also founded by Dean Kamen.

See also
Cryocooler

References

External links
 DEKA Research and Development Corp.

Companies based in Manchester, New Hampshire
Plug-in hybrid vehicle manufacturers
Contraflexure. In solid mechanics, a point along a beam under a lateral load is known as a point of contraflexure if the bending moment about the point equals zero. In a bending moment diagram, it is the point at which the bending moment curve intersects with the zero line (i.e. where the bending moment reverses direction along the beam). Knowing the place of the contraflexure is especially useful when designing reinforced concrete or structural steel beams and also for designing bridges.

Flexural reinforcement may be reduced at this point. However, to omit reinforcement at the point of contraflexure entirely is inadvisable as the actual location is unlikely to realistically be defined with confidence. Additionally, an adequate quantity of reinforcement should extend beyond the point of contraflexure to develop bond strength and to facilitate shear force transfer.

See also
 Deformation
 Engineering mechanics
 Flexural rigidity
 Flexural stress
 Fluid mechanics
 Inflection point
 Strength of materials

References

Solid mechanics