omniomni/omni-engineering huggingface dataset:
Marks' Standard Handbook for Mechanical Engineers. Marks' Standard Handbook for Mechanical Engineers is a comprehensive handbook for the field of mechanical engineering. Originally based on the even older German , it was first published in 1916 by Lionel Simeon Marks. In 2017, its 12th edition, published by McGraw-Hill, marked the 100th anniversary of the work. The handbook was translated into several languages.

Lionel S. Marks was a professor of mechanical engineering at Harvard University and Massachusetts Institute of Technology in the early 1900s.

Topics
The 11th edition consists of 20 sections:

 Mathematical Tables and Measuring Units
 Mathematics
 Mechanics of Solids and Fluids
 Heat
 Strength of Materials
 Materials of Engineering 
 Fuels and Furnaces
 Machine Elements
 Power Generation
 Materials Handling 
 Transportation
 Building Construction and Equipment
 Manufacturing Processes
 Fans, Pumps, and Compressors 
 Electrical and Electronics Engineering 
 Instruments and Controls 
 Industrial Engineering
 The Regulatory Environment
 Refrigeration, Cryogenics, and Optics
 Emerging Technologies

Editions

 English editions:
 1st edition, 1916, edited by Lionel Simeon Marks, based on the German 
 2nd edition, 1924, edited by Lionel Simeon Marks
 3rd edition, 1930, Editor-in-Chief Lionel S. Marks, total issue 103,500, McGraw-Hill Book Co. Inc.
 1941, edited by Lionel Peabody Marks
 1951, edited by Lionel Peabody Marks and Alison Peabody Marks
 1967, edited by Theodore Baumeister III
 6th edition, 1958, edited by Eugene A. Avallone, Theodore Baumeister III
 7th edition, golden (50th) anniversary, 1976?, edited by Theodore Baumeister III
 8th edition, edited by Theodore Baumeister III, Eugene A. Avallone
 9th edition
 10th edition, 80th anniversary, 1997, edited by Eugene A. Avallone, Theodore Baumeister III,
 11th edition, 90th anniversary, 2007, edited by Eugene A. Avallone, Theodore Baumeister III, Ali M. Sadegh
 12th edition, 100th anniversary, 2017, edited by Ali M. Sadegh, William M. Worek, Eugene A. Avallone

See also

References

External links
 Publisher's description

Mechanical engineering
Handbooks and manuals
1916 non-fiction books
Internal drive propulsion. Internal drive propulsion or water-jet propulsion is a form of marine propulsion used in recreational boating.  Like other forms of motorized boating, internal drive propulsion employs a motor that turns a propeller to move the boat forward. The primary difference between internal drive boats and external drive boats is that the propeller is enclosed inside the hull of an internal drive boat whereas the propeller is exposed outside the hull of a stern drive, V-drive or straight shaft drive boat.

A conventional screw propeller accelerates a large volume of water by a small amount, similar to the way an airplane propeller accelerates a large volume of air by a small amount. An aircraft's jet engine, by contrast, accelerates a smaller volume of air by a large amount. Both methods yield thrust due to Newton's third law — every force gives rise to an equal and opposite force.

In an internal drive boat, pumping a small volume of water and accelerating it by a large amount delivers the thrust. The acceleration of the water is achieved by using multiple impeller stages. Steering is accomplished by nozzles or small vanes that direct the water jet. Efficiency of the drive is related to the difference in speed of the vessel and the accelerated water producing the thrust. Jet drives are inefficient in low speed vessels, but may have other advantages that make them suitable for a given application.

Internal drive propulsion was originally designed by Sir William Hamilton (who invented the waterjet in 1954) for operation in the fast-flowing and shallow rivers of New Zealand, specifically to overcome the problem of propellers striking rocks in such waters.

Primary benefits:

  Water skiers, wakeboarders, swimmers, divers, etc. are not exposed to external propellers.
  Less potential for damage to internal drive boats from floating debris.
  Less potential for major drive damage from running aground as with exposed propellers.
  Better maneuverability and acceleration compared to stern-drive counterparts.

Disadvantages are usually low efficiency and high cost.

See also

External links
Yamaha Boats 

Marine propulsion
Lincoln Walsh. Lincoln Walsh (November 3, 1903 – November 17, 1971) was an engineer and inventor.

Early life and education 
Walsh received his B.S. in electrical engineering from Stevens Institute of Technology in 1926. He later studied at Columbia University and at Brooklyn Polytechnic Institute."LINCOLN WALSH, 68, OF ELECTRONIC FIRM", New York Times, Nov. 19, 1971.

Career 
After World War II, he founded Brooks Electronics Inc.  During the war, he worked with Rudy Bozak at the Dinion Coil Company in Caledonia, New York, developing high voltage power supplies for radar use.  Walsh worked as a member of the War Planning Board.

Walsh may have been involved in the development of the Kettledrum Baffle that one associates with the first Bozak speaker systems.  He redesigned the "Mark II" (Colossus computer) power supply to prolong the unit's life. Later, he was a consultant on very large transformer designs for power distribution.  He also developed a high-quality AM radio receiver and an aircraft collision avoidance system.

Walsh´s interests extended to loudspeaker design. With the help of Bozak, he developed a direct-radiator design using a single speaker with an aluminum foil cone, operating out of a vertical column, and offering a wide frequency response.  A Simple Quality Rating System for Loudspeakers and Audio Systems appeared in the Journal of the Audio Engineering Society for July, 1963.  He went on to invent the wide-range coherent transmission-line loudspeaker, which was granted U.S. Patent 3,424,873 in 1969 (filed in 1964). Walsh realized that if you took an inverted cone and drove it from the apex, you could have a speaker with a perfect 360-degree horizontal radiation pattern available to reproduce all the audible frequency range. The vertical dispersion was controllable with the choice of materials. This offered a wide variety of designs, based on his patent.

Personal life 
As a member of the War Planning Board, he met and later married Harriet Walsh.  They were residents of Millington, New Jersey for many years. They had no children.

Legacy 
In 1971, Martin Gersten founded Ohm Acoustics. Gersten raised the capital needed to buy back the Walsh patent rights from a metal-casting company which had invested with Walsh.  Walsh's new speaker design was developed and marketed by Ohm (the Ohm 'A'), after Gersten invented an edge-wound anodized aluminum voice coil, U.S. Patent 3,935,402 (1974), which was needed to make the unit viable.  Unfortunately, Walsh died before his speaker was released to the public. Ohm Chief Engineer, John Strohbeen, further developed Walsh's concepts.

References

External links 
 http://www.aes.org/aeshc/docs/jaes.obit/JAES_V20_1_PG080.pdf
 http://www.ohmspeakers.com/
 https://web.archive.org/web/20180506020339/http://www.german-physiks.com/technology/the-ddd-driver.html
 https://www.theaudiocritic.com/back_issues/The_Audio_Critic_29_r.pdf

1903 births
1971 deaths
American consultants
Place of birth missing
20th-century American inventors
Brooklyn College alumni
Stevens Institute of Technology alumni
Columbia University alumni
Barbados Light and Power Company. The Barbados Light & Power Company Limited (BL&P Co.) is a wholly owned subsidiary of Emera Caribbean and currently the sole electricity utility provider in the country of Barbados. It started operations on 17 June 1911.  The company claims it has over 100,000 customers. The fuel provided is natural gas and fuel oil.

Generation 
The company operates three power generating plants:
 Two are located in the Parish of St. Michael: One situated north of the Deep Water Harbor, along the Mighty Grynner Highway, and a second on Bay Street, at The Garrison. 
 A third is located in Seawell, Christ Church, at the Grantley Adams International Airport.

Other power generated substations were:
the Belmont Road Substation in Belmont Road, St. Michael;
the Central Substation in Haggatt Hall, St. Michael;
the Kendall Hill Substation in Kendall Hill, Christ Church;
the Maynards Substation in Maynards, St. Peter;
the Whitepark Road Substation in Whitepark Road, St. Michael;
the Carrington Substation in Carrington, near Hampton, St. Philip,
the Carmichael Substation in Carmichael, St. George;
the Arch Hall Substation in Arch Hall, St. Thomas;
the Carlton Substation in Carlton Road, St. James;
the Sion Hill Mini-substation in Springhead Road, Sion Hill, St James;
the Regency Park Mini-substation in Regency Park, Bartletts, Christ Church;
the Trents Substation in Trents, St. Lucy; and
the Warrens Substation in Warrens, St. Michael.

Current 
Power is transmitted at 24 kV, which is then distributed at 11 kV and consumed at 115/200 volts or 115/230 volts (residential), 230/400 volts (commercial), or 11,000–24,900 volts for industry at a frequency of 50 hertz.

Electricity rates in Barbados are claimed to be some of the highest in the Caribbean. However, the company is currently in the process of negotiating a direct undersea pipeline for natural gas from Trinidad and Tobago through the Eastern Caribbean Gas Pipeline.

BL&P is also engaged in a long-term study of the feasibility of creating a wind farm off the north coast of Saint Lucy.

The Barbados Light & Power Company is a member of the Saint Lucia based Caribbean Electric Utility Services Corporation (CARILEC), and the Solar Electric Power Association (SEPA) based in Washington, DC, USA.

The Barbados Light & Power Company celebrated its 100th anniversary on 17 June 2011, with the slogan "Electricity: powering our nation since 1911."

See also

Reddy Kilowatt
Mains electricity by country
NEMA connector
U.S. National Electrical Code
List of companies listed on the Barbados Stock Exchange

References

External links
The Barbados Light & Power Company Limited Official website
History of The BL&P Co.

Electric power companies of Barbados
Energy companies established in 1911
Non-renewable resource companies established in 1911
Public utilities established in 1911
1911 establishments in Barbados
Emera
Barbados Water Authority. Barbados Water Authority Limited (BWA), a government statutory corporation, is the sole provider of water services. Water supplied by the BWA in Barbados is pumped from wells within natural coral aquifers.  The geology of Barbados is mostly composed of karst limestone which acts as a filter medium within the aquifers.  The water service in Barbados is reliable and the water supply is safe and refreshing to drink; although the water source naturally of high quality, the BWA treats the potable water supply with chlorine to comply with World Health Organization (WHO) standards.

Desalination plant
Due to high demand, a desalination plant was built to augment the existing groundwater.  Currently supplying for up to 20 per cent of the population, the joint General Electric and Williams Industries-owned facility at Brighton, St. Michael; it currently produces about 23,000 cubic metres of potable water per day, (with maximum capacity for 30,000 cubic metres.)
The plant takes brackish water from ten 80-foot wells located near its St. Michael operation and the water is pretreated and then desalted to produce potable water.

Distribution network
Typically, water is conveyed by pumps at the individual sources to elevated reservoirs for storage before distribution to consumers by gravity. The headquarters of the BWA are at The Pine in St Michael.

Prior to the introduction of indoor plumbing to all of the houses on the island, it was a common practice for most areas in Barbados to have a communal-based standpipe.  Neighbourhood standpipes have since been turned off at many points across the island due to several instances where persons were found using the standpipe to conduct things like washing their cars in order to avoid paying for the high water usage at their residence.

References

Further reading
St. Michael BWRO Desalination Plant, Barbados
About Ionics Freshwater Limited, Williams Industries
Water and the Consumer - Barbados Ministry of Commerce, Consumer Affairs and Business Development
Caves and landslips in Barbados - September 16, 2007: Barbados Advocate

External links
Barbados Water Authority - BWA - Official website
Ionics Freshwater Limited

Government agencies of Barbados
Service companies of Barbados
NSB El 12. NSB El 12 was an electric locomotive used by the Norwegian State Railways (NSB) to haul iron ore trains on Ofoten Line between 1957 and 1990. The locomotives were based on the Swedish Dm that was used with success on the connecting Iron Ore Line. The eight units were always operated in pairs or in triples and were numbered 12 2113 - 12 2120. Four double sets remain as heritage locomotives.

History

After World War II the production resumed at the mines operated by LKAB at Kiruna and Malmberget with estimates of a 50% production increase within few years. To solve the problems with increased traffic, the railway companies had the choice of either building double track or hauling longer trains. The latter solution was chosen, and on the Norwegian side the ten El 3 locomotives were converted from five double sets to three triple sets with one reserve and the two El 4 converted to a double set. But this solution would require more locomotives.

The Swedish State Railways (SJ), who operated the trains from the mines to Riksgränsen, chose to buy 12 Dm units in 1952, based on the Da units from 1950. NSB chose to buy six more or less identical units from Motala Verkstad in 1954 and an additional two in 1957 from NOHAB. But the ore production continued to increase, and in 1960 SJ ordered a middle section for their Dm units, creating the Dm+Dm3+Dm unit configuration. NSB chose to rebuild three of their locomotive pairs to triple units, but in 1967 NSB ordered six new technically far more advanced El 15 locomotives. The El 12 units were taken out of service between 1989 and 1992.

15 kV AC locomotives
El 12
NOHAB locomotives
Ofoten Line
Electric locomotives of Norway
Railway locomotives introduced in 1954
Standard gauge locomotives of Norway
1′D+D1′ locomotives
Depolymerization. Depolymerization (or depolymerisation) is the process of converting a polymer into a monomer or a mixture of monomers. This process is driven by an increase in entropy.

Ceiling temperature
The tendency of polymers to depolymerize is indicated by their ceiling temperature.  At this temperature, the enthalpy of polymerization matches the entropy gained by converting a large molecule into monomers.  Above the ceiling temperature, the rate of depolymerization is greater than the rate of polymerization, which inhibits the formation of the given polymer.

Applications
Depolymerization is a very common process.  Digestion of food involves depolymerization of macromolecules, such as proteins.  It is relevant to polymer recycling. Sometimes the depolymerization is well behaved, and clean monomers can be reclaimed and reused for making new plastic.  In other cases, such as polyethylene, depolymerization gives a mixture of products. These products are, for polyethylene, ethylene, propylene, isobutylene, 1-hexene and heptane. Out of these, only ethylene can be used for polyethylene production, so other gases must be turned into ethylene, sold, or otherwise be destroyed or be disposed of by turning them into other products.

Depolymerization is also related to production of chemicals and fuels from biomass.  In this case, reagents are typically required.  A simple case is the hydrolysis of celluloses to glucose by the action of water.  Generally this process requires an acid catalyst:
H(C6H10O5)nOH  +  (n - 1) H2O   →    n  C6H12O6

See also
 Thermal depolymerization
 Polymer degradation
 Polymerisation
 Ceiling temperature
 Chain scission

References

External links

Polymers
Plastic recycling
ASJA L2. 

The ASJA L2 was a Swedish biplane trainer aircraft built for the Swedish Air Force in the early 1930s. It was designated Ö 9 in that service. The fuselage was of fabric-covered, welded steel tube construction and accommodated the pilot and instructor in tandem open cockpits. The wings were fabric-covered wood and were of staggered, single bay layout.

Only two examples were built, one with wheels and the other with floats. The landplane served until written off in a crash in 1937 and the floatplane until made obsolete in 1940.

Operators

Swedish Air Force

Units using this aircraft
 Wing F 1 at Västerås
 Wing F 2 at Hägernäs

Specifications

References
 
 Military Aviation in Sweden (website)

1930s Swedish military trainer aircraft
Single-engined tractor aircraft
L2
Biplanes
Aircraft first flown in 1932
NSB El 3. NSB El 3 was an electric locomotive used by the Norwegian State Railways (NSB) to transport iron ore on the Ofoten Line. Five twin-locomotive sets were in service from 1925 to 1967.

History 

The Swedish part of the ore line, the Iron Ore Line, was electrified in 1915 but Norway kept using steam locomotives until the Norwegian electrification in 1923. As Norwegian traction the El 3 was chosen along with five triple-engine El 4 units. Eight El 3 were built with delivery on August 9, 1925, two more on October 19, 1929. The El 3 and El 4 had about the same characteristics and used for the same purpose and ordered simultaneously; choosing two models like this is atypical for railway companies because of higher maintenance costs.

By 1922 SJ had placed an order on the new Of-locomotives, yet NSB chose to base the El 3 on the older Oe. Build by ASEA, they were equipped with quill drive and regenerative braking; the latter only caused problems though, excessively increasing the current that caused damage. They only served on the Norwegian lines until 1949, after which they were where put into through trains to Kiruna. In 1950 LKAB decided to increase the mine output, requiring trains now to haul . In 1953-54 the locomotives were rebuilt to three triple-engine sets and supplemented with eight El 12. When LKAB chose to increase train weights more in the late 1960s, NSB responded with the order of the El 15. All El 3 and El 4 units were taken out of service with the delivery in 1967, none being preserved.

External links 
 Jernbane.net page on El 3 with pictures 

15 kV AC locomotives
El 03
Siemens locomotives
AEG locomotives
Ofoten Line
Electric locomotives of Norway
Railway locomotives introduced in 1925
(1′C)+(C1′) locomotives
Para-Mail. Para Mail was a proprietary, electronic mail client that was developed and maintained by Kris Land and his team. It was originally released in 1985 for MS-DOS, but was subsequently ported to Microsoft Windows. A version for Apple Macintosh also used to be available.

On January 3, 1990, it was announced that Paradox Development of Para-Mail was acquired by Office Automation Systems later known as OCTuS, Inc.

Features 
Para-Mail was suitable for single or multiple users on stand-alone computers or on local area networks. A key feature of Para-Mail was that it supported image scanners, faxes, optical character recognition and voice mail all through one common user interface.

The original version worked with Novell NetWare networks and its Novell's Message Handling System (MHS) mail system; a cut-down MHS-only version called PM-Remote was bundled with NetWare. Early versions used an idiosyncratic format for mail folders; later versions offer the standard Unix mailbox format as an alternative to the historical Para-Mail format.

Para-Mail supported the x.400, x.500 protocols as well as Novell's MHS. 

From being the de facto standard email client on Novell NetWare networks, Para-Mail, along with Eudora and others suffered a similar fate to Netscape Navigator when Internet Explorer version 3.0 bundled Microsoft Internet Mail and News version 1.0 free-of-charge within Windows 95.

References

Email clients
Liming (leather processing). Liming is a process used for parchment or leather processing, in which hides are soaked in an alkali solution. It is performed using a drum and paddle or a pit. Its objectives are:
 Removal of interfibrillary proteins.
 Removal of keratin proteins.
 Collagen swelling due to the alkaline pH.
 Collagen fibre bundle splitting.
 Removal of natural grease and fats

Liming operations of cattle hides usually last 18 hours and are generally associated with the alkaline phase of beamhouse operations.

Removal of interfibrillary proteins
The interfibrillary proteins are denatured by the presence of alkali (particularly sodium sulfide), rendered soluble, facilitating their removal from the leather. Removal is done by the mechanical action of liming or reliming, but more prominently when the pelt is deswelled (during deliming). Failure to remove these proteins results in a hard, tinny leather (due to fibre glueing upon drying) that is brittle and inflexible.

Keratin removal
Keratin that is present in the hair, scales and in the epidermis of the skin is hydrolyzed in the presence of alkali (at pH values greater than 11.5). The disulfide bridges found in keratin protein are cleaved but can be reformed. Long periods of liming will result in hair removal. The main removal of keratin is performed during the unhairing operation. In traditional processing, liming and unhairing were indivisible and took place at the same time. During modern liming methods, and in particular the processing of sheepskins, the hair is removed first and then limed in a liming drum. In hair-save technology, the hides are unhaired first and then limed for a further 12–18 hours.

Alkaline collagen swelling
The presence of calcium hydroxide results in the alkaline swelling of skin. The result is an influx of water into the hide/skin, and a marked increase in fibre diameter and fibre shortening. The thickness of the skin increases, but the surface area of the pelt decreases. The weight increase, owing to the uptake of water, results in a doubling of the hide/skin weight. However, this weight also needs to take into consideration that proteins (especially the hair) have been removed, and the fleshing operation is often performed after liming.

Collagen fibre bundle splitting
The action of liming, in particular the swelling of the skin, results in the splitting of the fibre bundle sheath. Owing to the fibre diameter increasing, the bundle sheath cannot contain the thicker fibres, and it bursts open. This allows increased access to the fibres, which allows better tanning, retanning, dyeing and fatliquoring.

References

Leathermaking