Applied Mechanics Division

The Applied Mechanics Division (AMD) is a division in the American Society of Mechanical Engineers (ASME). The AMD was founded in 1927, with Stephen Timoshenko being the first chair. The current AMD membership is over 5000, out of about 90,000 members of the ASME. AMD is the largest of the six divisions in the ASME Basic Engineering Technical Group.
Mission.
The mission of the Applied Mechanics Division is to foster fundamental research in, and intelligent application of, applied mechanics.
Summer Meeting.
The Division participates annually in a Summer Meeting by programming Symposia and committee meetings. The principal organisers of the Summer Meetings rotate among several organizations, with a period of four years, as described below.
Awards.
These awards are conferred every year at the Applied Mechanics Division Banquet held during the annual ASME (IMECE) conference. Awards other than those mentioned above are also celebrated during this banquet, such as the Haythornthwaite Research Initiation Grant Award and the Eshelby Mechanics Award for Young Faculty.
Executive committee.
The responsibility for guiding the Division, within the framework of the ASME, is vested in an Executive Committee of five members. The Executive Committee meets twice a year at the Summer Meeting and Winter Annual Meeting. Members correspond throughout the year by emails and conference calls. Three members shall constitute a quorum, and all action items must be approved by a majority of the Committee.
Each member serves a term of five years, beginning and ending at the conclusion of the Summer Meeting, spending one year in each of the following positions:
New members of the Executive Committee are sought from the entire membership of the Division. Due considerations are given to leadership, technical accomplishment, as well as diversity in geographic locations, sub-disciplines, and genders. At the Winter Annual Meeting each year, the Executive Committee nominates one new member, who is subsequently appointed by the ASME Council.
The executive committee has an additional non-rotating position, the Recording Secretary. The responsibility of the Recording Secretary is to attend and record minutes for the Executive Committee Meeting at the Summer and Winter Annual Meeting and the General Committee Meeting at the Winter Annual Meeting. The Recording Secretary serves a term of two years and is selected from the junior members (i.e. young investigators) of the AMD.
Current members of the Executive Committee
Technical Committees.
The mission of a Technical Committee is to promote a field in Applied Mechanics. The principal approach for a Technical Committee to accomplish this mission is to organize symposia at the Summer and Winter Meetings. Technical Committees generally meet at the Winter Annual Meeting and the Summer Meeting; they may also schedule special meetings.
There are 17 Technical Committees in the Applied Mechanics Division.
Technical Committees are established and dissolved by the Executive Committee.
History.
See Naghdi's "A Brief History of the Applied Mechanics Division of ASME" for details of the history from 1927-77.
Past chairs of the Applied Mechanics Division.
Balakumar Balachandran (2019),
Pradeep Sharma (2018),
Arun Shukla (2017),
Peter Wriggers (2016),
Huajian Gao (2015),
Lawrence A. Bergman (2014),
Ken Liechti (2013),
Ares Rosakis (2012),
Tayfun Tezduyar (2011),
Zhigang Suo (2010),
Dan Inman (2009),
K. Ravi-Chandar (2008),
Thomas N. Farris (2007),
Wing Kam Liu (2006),
Mary C. Boyce (2005),
Pol Spanos (2004),
Stelios Kyriakides (2003),
Dusan Krajcinovic (2002),
Thomas J.R. Hughes (2001),
Alan Needleman (2000),
Lallit Anand (1999),
Stanley A. Berger (1998),
Carl T. Herakovich (1997),
Thomas A. Cruse (1996),
John W. Hutchinson (1995),
L.B. Freund (1994),
David B. Bogy (1993),
William S. Saric (1992),
Ted Belytschko (1991),
Michael J. Forrestal (1990),
Sidney Leibovich (1989),
Thomas L. Geers (1988),
James R. Rice (1987),
Michael M. Carroll (1986),
Jan D. Achenbach (1985),
Charles R. Steele (1984),
William G. Gottenberg (1983),
R.C. DiPrima (1982),
R.M. Christensen (1981),
R.S. Rivlin (1980),
Richard Skalak (1979),
F. Essenburg (1978),
Yuan-Cheng Fung (1977),
J. Miklowitz (1976),
B.A. Boley (1975),
George Herrmann (1974),
J. Kestin (1973),
Paul M. Naghdi (1972),
S. Levy (1971),
H.N. Abramson (1970),
Stephen H. Crandall (1969),
P.G. Hodge Jr. (1968),
R. Plunkett (1967),
M.V. Barton (1966),
George F. Carrier (1965),
Daniel C. Drucker (1964),
E. Reissner (1963),
A.M. Wahl (1961, 1962),
S.B. Batdorf (1960),
William Prager (1959),
W. Ramberg (1958),
M. Hetenyl (1957),
Raymond D. Mindlin (1956),
Nicholas J. Hoff (1955),
N.M. Newmark (1954),
D. Young (1953),
R.E. Peterson (1952),
L.H. Donnell (1951),
R.P. Kroon (1950),
M. Golan (1949),
W.M. Murray (1948),
H.W. Emmons (1947),
H. Poritsky (1946),
J.N. Goodier (1945),
J.H. Keenan (1943, 1944),
H.L. Dryden (1942),
J.P. Den Hartog (1940, 1941),
C.R. Soderberg (1937,1938),
E.O. Waters (1936),
J.A. Goff (1935),
F.M. Lewis (1934),
J.M. Lessells (1933),
G.B. Pegram (1932),
A.L. Kimball (1931),
G.M. Eaton (1928, 1929),
Stephen P. Timoshenko (1927, 1930)


V-mount

V-mount may refer to:


Oval electric ray

The oval electric ray ("Typhlonarke aysoni") is a little-known species of sleeper ray in the family Narkidae. It is endemic to New Zealand, where it is generally found on the sea floor at a depth of . Seldom exceeding in length, this species has a thick, oval pectoral fin disc and a short, stout tail with a single dorsal fin. It is blind, as its tiny eyes are covered by skin. Its pelvic fins are divided in two, with the anterior portion forming a limb-like appendage. These appendages likely allow the ray, which may not be able to swim at all, to "walk" along the bottom. The claspers of adult males extend beyond the disc. Polychaete worms are known to be part of its diet, and its reproduction is aplacental viviparous. It can produce an electric shock for defense. The International Union for Conservation of Nature presently lacks the data to assess its conservation status.
Taxonomy.
The oval electric ray was described by William John Phillipps of the Dominion Museum, in a 1929 volume of the "New Zealand Journal of Science and Technology". The type specimen was collected off Island Bay, Wellington. A specimen of this ray had been illustrated earlier by Augustus Hamilton, in his 1909 description of the related "T. aysoni". Hamilton obtained the specimen at the fish market at Dunedin and made note of its different shape, but did not recognize it as a distinct species. Along with "T. aysoni", this species may also be called the blind electric ray.
Distribution and habitat.
Confusion between the two "Typhlonarke" species has led to uncertainty regarding the extent of the oval electric ray's distribution. Both species are found off the eastern coast of New Zealand, between the East Cape of North Island and the Snares Shelf south of South Island, including the Cook and Foveaux Straits and the Stewart and Chatham Islands. Bottom-dwelling in nature, this species is generally found at a depth of but has been recorded from as shallow as and as deep as .
Description.
The pectoral fin disc of the oval electric ray is ovoid in shape, tapering smoothly towards the rear, and has a very thick margin. The eyes are minute and located beneath the surface of the skin; though not visible externally, their positions are marked by small white patches. The spiracles follow the eyes and are oval with smooth rims. The nostrils are closely together, with their outer rims curled to nearly form tubes and their inner rims expanded and fused together into a fleshy skirt-shaped curtain, that nearly conceals the small, deeply recessed mouth. The teeth number 11 rows in either jaw and are arranged with a quincunx pattern to form narrow plates restricted to the front of the jaws. The teeth in the back have a single sharp cusp, while those at the front are worn down and blunt. There are five pairs of short, curved gill slits, with the first and fifth pairs smaller than the others.
Each pelvic fin is divided: the anterior portion is formed into a long appendage resembling a finger, while the posterior portion is merged smoothly with the pectoral fin to form part of the disc. The trailing margins of the pelvic fins join the body evenly, without a notch. Adult males have cylindrical claspers that extend past the disc margin. The single dorsal fin has a rounded margin and originates just ahead of where the disc margin meets the body. The tail is short and thick, with faint lateral skin folds running along the sides, and ends in a nearly circular caudal fin. The skin is completely smooth. The oval electric ray is dark brown above, lightening towards the disc margins and on the underside. The area around the mouth and nostrils, and the underside of the pelvic appendages, are white. This species can grow to long, but most do not exceed .
Biology and ecology.
Thick and flabby with a rudimentary tail, the oval electric ray seems virtually incapable of swimming. Instead, it likely relies on its mobile pelvic fin appendages, which are better developed than those of "T. aysoni", to push it along the bottom. Like other electric rays, it can produce a defensive electric shock from a pair of kidney-shaped electric organs placed on either side of its head. Each organ consists of 180–200 relatively large, fluid-filled hexagonal columns, which essentially act as batteries connected in parallel. The oval electric ray is sightless and captures prey via suction; it is known to feed on polychaete worms. It is aplacental viviparous, with females bearing litters of up to 11 pups. The newborns measure long.
Human interactions.
The oval electric ray is susceptible to capture in bottom trawls, and the presence of major commercial fishing activity within its range may merit concern. However, given insufficient data the International Union for Conservation of Nature (IUCN) has listed it under Data Deficient. In June 2018 the New Zealand Department of Conservation classified the oval electric ray as "Not Threatened" with the qualifier "Data Poor" under the New Zealand Threat Classification System.


2872d Test Squadron


Abdul Majid (physicist)

"For other people with the same or similar name, see Abdul Majid"
Abdul Majid (Urdu):(عبد الماجد) is a Pakistani astrophysicist and scientist in the field of space technology. He is a former chairman of Space and Upper Atmosphere Research Commission from 1997 to 2001. He had made significant contributions to Pakistan's space program. During his tenure as SUPARCO Administrator, Pakistan launched its two Low Earth orbit (LEO) satellites, which were masterminded and developed by him. He also initiated a satellite launch vehicle (SLV) project at SUPARCO. He retired from SUPARCO in 2001 as a chief scientist. Since his retirement, he has been inactive from Pakistan's space program and currently resides in Karachi where he lives a very quiet life there.
Education.
Abdul Majid was born in Narowal, Pakistan from where he received his elementary and high school education. He received BSc (hons) and MSc in Nuclear Physics from Government College, Punjab University in 1962 and was awarded the Roll of Honours. His thesis on 'Radiative Capture of Neutrons' was rated as one of the best ever submitted for a master's degree by Rafi M. Chaudhary.
Under NASA fellowship program he studied Astrogeophysics at Colorado University, Boulder, Colorado. For his PhD he worked on Radio interferometric detection of Gravity Waves under Sir Granville Jones/PJSWilliams at the University of Wales, Aberystwyth UK. The project involved fabrication of phase switched receivers as an integral constituent of widely spaced radio interferometers. The system detected gravity waves as travelling ionospheric disturbances.
SUPARCO career.
After his PhD, he came back to Pakistan and joined Pakistan's Space Program as a researcher in astrophysics and aeronautical labs. Majid worked under the supervision of noted Pakistani-Polish military scientist and aeronautical engineer, Air Commodore W. J. M. Turowicz, in the field of Rocket Technology and published numerous research papers. He is credited for the design and developed the Hypersonic Rocket Launch Vehicle or Hatf Missiles Series during his stay at SUPARCO.
In 1983, Majid was put in-charge of Satellite Development Program of Pakistan. He is widely credited for the indigenous development and launching of BADR-1 and development of Badr-B Earth Observation Satellites. He was keen to develop Pakistan's Space Launch capabilities and met with both former Prime Minister of Pakistan, Nawaz Sharif and Benazir Bhutto to gain their approval for the project. The project however was not sanctioned due to economic constrains.
In 1992, Abdul Majid travelled to Russia, where he was able to sign a deal in 1995 with Russian Federal Space Agency to launch the Pakistani Satellite with a given deadline. According to him, Russians agreed to launch Pakistan's domestically built satellite from their soil. The satellite was completed in 1999 and was transported to Russia in early 2000.
After an initial success in satellite development, Abdul Qadeer Khan met with Majid where they discussed Majid's indigenously designed Low Earth orbit satellite project. In 1999, Majid, as then-Chairman of Pakistan's Space and Upper Atmosphere Research Commission (SUPARCO) announced that Pakistan would develop its own satellite launching vehicle within a period of about three years. He also met then-Chief executive of Pakistan, Gen. (r). Pervez Musharraf in the army house. He, along with Abdul Qadeer Khan, briefed General Musharraf about the project where Majid received his green signal. However, the SLV Project's status remains unclear.


Magnetic tension force

The magnetic tension force is a restoring force (SI unit: Pa·m−1) that acts to straighten bent magnetic field lines. It equals:
It is analogous to rubber bands and their restoring force. The force is directed antiradially. Although magnetic tension is referred to as a force, it is actually a pressure gradient (Pa⋅m−1) which is also a force density (N⋅m−3).
The magnetic pressure is the energy density of the magnetic field which can be visualized as increasing as magnetic field lines converge in a given volume of space. In contrast, magnetic tension force is determined by how much the magnetic pressure changes with distance. Magnetic tension forces also rely on vector current densities formula_2 and their interaction with the magnetic field formula_3. Plotting magnetic tension along adjacent field lines can give a picture as to their divergence and convergence with respect to each other as well as current densities formula_2.
Use in plasma physics.
Magnetic tension is particularly important in plasma physics and magnetohydrodynamics, where it controls dynamics of some systems and the shape of magnetized structures.
In magnetohydrodynamics, the magnetic tension force can be derived from the momentum equation of plasma physics:
The first term on the right hand side of the above equation represents electromagnetic forces and the second term represents pressure gradient forces. Using the relation formula_6 and the vector identity
we obtain the following equation:
The first and last gradient terms are associated with the total pressure which is the sum of the magnetic and thermal pressures; formula_9. The second term represents the magnetic tension.
We can separate the force due to changes in the magnitude of formula_3 and its direction by writing formula_11 with formula_12 and formula_13 a unit vector. Some vector identities give
The first term is the "magnetic pressure" due solely to changes in formula_15 in directions perpendicular to formula_3, while the second term is the "tension" due solely to changes in the direction of formula_3 (or curvature of magnetic field lines).
A more rigorous way to look at this is through Maxwell stress tensor. The Lorentz force law
gives the force per unit volume:
This, after some algebra and using Maxwell's equations to replace the current, leads to
This result can be re-written more compactly by introducing the Maxwell stress tensor,
All but the last term of the above expression for the force density, formula_22, can be written as the divergence of the Maxwell tensor:
which gives the electromagnetic force density in terms of Maxwell stress tensor, formula_24, and the Poynting vector, formula_25. Now, the magnetic tension is implicitly included inside formula_24. The implication of the above relation is the conservation of momentum. Here, formula_27 is the momentum flux density and plays a role similar to formula_28 in Poynting's theorem.


QBU-88

The QBU-88 sniper rifle is a Chinese bullpup designated marksman rifle developed by Norinco for the People's Liberation Army.
History.
During the 1979 Sino-Vietnamese War, China captured samples of the Soviet-designed Dragunov sniper rifle, which it copied as the Type 79. Due to immature gunsmithing techniques its firing pin could break from metallurgy issues and problems copying the PSO-1 4x scope made it unable to handle the recoil of firing its rounds. These issues were addressed in the upgraded Type 85, but the PLA still used standard ball ammunition rather than specialized sniping cartridges, resulting in lower accuracy. These shortfalls led to development of a new sniper rifle when China started development of a new cartridge for machine guns in the early 1990s.
The QBU-88 rifle (also sometimes referred to as Type 88 rifle) was the first weapon of the newest generation of Chinese small arms, chambered for proprietary 5.8×42mm DBP87 ammunition. Adopted in 1997, the QBU-88 is, by the modern sense, not a true sniper rifle – it is more a designated marksman rifle, intended for aimed semi-automatic fire at ranges beyond the capabilities of standard infantry assault rifles. The rifle is intended for rough military use, so it is fitted with adjustable iron sights by default, and is generally equipped with telescopic sights or with night sights.
QBU-88 rifle is optimized for a special heavy loading of 5.8×42mm cartridge with a longer streamlined bullet with steel core. It can also fire standard ammunition intended for the QBZ-95 assault rifles. At the present time the QBU-88 rifle is in service with PLA and Chinese police forces.
Design details.
The QBU-88 rifle is a gas-operated semi-automatic rifle. It utilizes a short-stroke gas piston, located above the barrel, and three-lug rotating bolt. The action is mounted in the compact steel receiver, and enclosed into a polymer bullpup-type housing. To increase accuracy, the action is mated to a 640 mm (25.1 in) long, hammer-forged match-grade barrel. The safety switch is located at the bottom of the receiver, just behind the magazine opening. The QBU-88 rifle is equipped with open, diopter-type adjustable sights, mounted on folding posts. It also has a short proprietary dovetail rail on the receiver which can accept telescope or night sight scope mount.
The rifle is intended to be utilized primarily with optics. The standard day optic used on the QBU-88 for military use is a Chinese 3-9×40 scope with an integral quick-release mount. In 2008 a new Chinese 6-24×44 tactical scope became available for counter-terrorism and other law enforcement use.
The riflings for the QBU-88 differs from the standard QBZ-95 assault rifle. While the QBZ-95 has a twist to stabilize the standard 64-grain DBP-87 ball round, the QBU-88 has a faster twist to stabilize the 70-grain Heavy Ball round and dedicated Sniper load, similar to the QJY-88 general-purpose machine gun, which has progressive rifling with a final twist rate of 206 mm. A long birdcage flash suppressor is fitted to reduce the muzzle signature. A quick-detachable bipod is clamped to the barrel when required.
Variants.
An export version called the KBU-97a is also produced and marketed for security forces of other foreign countries. This derivative utilizes 5.56×45mm NATO ammunition although, instead of STANAG magazine, a modified version of QBU-88 magazine is used to feed the rounds – and STANAG magazines will not work unless modified. The KBU-97A has recently been sighted under the designation NQU03, though it is unknown if the two differentiate in any way aside from name.


German Jubilate Harmonium Reeds

German Jubilate Harmonium Reeds are brass reeds used in Indian harmoniums that were manufactured in Germany between 1911 and the early 1960s. The reeds were originally manufactured for American style suction reed organs being manufactured in Germany on machinery that was bought second hand in Chicago in the United States and imported to Germany by Karl Mannborg son of Theodor Mannborg. Mannborg owned the factory in Pegau, Germany supplying organ parts for American style suction reed organs. Germany (and later in England) was the only country in Europe that was manufacturing American style suction reed organs while the rest of the reed organ industry in Europe was making pressure reed Harmoniums.
Indian harmoniums.
In the 1930s and 1940s the demand in Europe for reed organs and harmoniums significantly declined and the factory started exporting the reeds to India where Indian style hand-pumped harmoniums had become very popular creating the demand and a market for the German harmonium reeds. Although these organ reeds were originally designed and manufactured for American style suction organs they became the favored reeds for their tone quality and tuning stability in Indian hand pumped harmoniums which work on an air pressure system. In order for them to be attached to the Indian harmonium reed board (as opposed to sliding into the reed chambers as they did on the reed organs) holes were drilled at the top tongue end of the reed casing and a notch was drilled at the base end. This enabled the German reeds to be screwed directly and tightly onto the reed board with the reed tongue over the air holes connected to the playing keys. Subsequently, the factory began selling the reed sets labeled as Jubilate/Harmola/Monarch and several other branded names as Harmonium Brass Reeds Made in Germany with the screw holes already drilled in the outer reed casing to suit the Indian harmonium market. The distinguishing visual features of the German Jubilate reeds are the words Jubilate, Harmola or Monarch (and other branding names) and Made in Germany which are stamped on each individual reed in addition to the pitch of the reed and the distinct rounded bottom edge of the casing at the tongue end of the reed. There were also German reeds that were stamped with only "Made in Germany" and some were stamped only with the note/pitch of the reed. The latter version with the note/pitch stamp only can be identified by the distinct rivet structure securing the reed tongue on the German reeds which is the mostly the same on all versions of these reeds made on the same machinery in Germany. There is debate that the reeds branded 'Harmola' were made on a different machine elsewhere TBD. Most of the German reeds used in the Indian style harmoniums do not have the typical reed tongue shaping for the voicing of the reeds found in American or German style suction organs. There are also German Jubilate branded reeds that are the typical square casing design of harmonium reeds and very rare to find and prized. There have been considerable attempts to find out when this design was made in relation to the typical German rounded casing at the tongue end.
End of German Jubilate reed production.
In the early 1960s the factory making the German organ reeds used in the Indian sub-continent for harmoniums, having changed hands several times and now situated in post World War II East Germany (GDR), was taken over by the communist government and the reed making machinery was scrapped. This marked the end of German reed production. In the late 1970s India had also issued a ban on the importing of any German harmonium reeds to boost sales and promote the production of harmonium reeds being made in India. As a result, the demand and the value of the German reeds increased as did the scarcity of availability although they were still exported to Pakistan which was not using Indian harmonium reeds because or trade restrictions between the two countries. Today German reeds are highly prized and sought after by players of Indian harmoniums in India, Pakistan and Bangladesh as well as around the globe.
Notable recordings.
Some of the most notable recordings of the classic, clear and distinct tone of German harmonium reeds can be heard on the harmonium playing of the late Farukkh Fateh Ali Khan, brother and lead harmonium accompanist of the late Qawwali legend Nusrat Fateh Ali Khan from Pakistan. It is common practice in Pakistani Sufi Qawwali circles that a serious Qawwali harmonium player must have German reeds in their harmoniums.
Reed configuration.
The typical German Jubilate reed configuration in Pakistani Qawwali harmoniums is one bank of Bass (8') reeds starting on C and a bank of Male (4') reeds (octaves apart) starting on C that sound together on one note being played with an engaged (most often permanently) right action octave coupler (a mechanism located under the keyboard that simultaneously couples and plays the same note/key an octave higher with the lower note or notes being played on the harmonium to create a strong and full sound). Often the lowest octave of German Bass (8') reeds is not easily available and is therefore substituted with Indian Delhi style brass reeds for the first bass 12 reeds. One detail to note is that very often German reeds taken from old harmoniums in Kolkata show clear signs of cross filing which is apparently part of voicing the reeds for the tongues to respond faster and require less air to sound. The tone of these voiced reeds is distinctly different from the standard German reeds and closer resembles the tonal quality of Indian reeds yet still being unique in the actual tone.


2009 USS Port Royal grounding

The 2009 USS "Port Royal" grounding was a ship grounding by the United States Navy guided missile cruiser "Port Royal" off Oahu, Hawaii on 5 February 2009. The ship ran aground on a coral reef, damaging both the ship and the reef. The incident received wide press coverage in Hawaii, in part because of the damage caused to a sensitive coral environment, and also because the stranded ship was within sight of Honolulu off the airport.
Navy investigation found that the grounding was caused by a combination of a misread navigation system, a sleep-deprived commanding officer, broken equipment, and an inexperienced and dysfunctional bridge team. Commanding officer Captain John Carroll was relieved of duty and disciplined. Three other officers and one enlisted sailor were also disciplined. The Navy reattached 5,400 coral colonies in an attempt to repair damage to the reef.
Grounding.
"Port Royal" spent time in the Pearl Harbor shipyard for $18 million in scheduled repairs, then departed for the open ocean off Oahu for sea trials at 08:15 on 5 February 2009. The ship's fathometer was broken. At 12:01, the automated navigation system's primary input was shifted from a forward Global Positioning System to forward Ring Laser Gyro Navigation, an inertial navigator. Three times the Voyage Management System dead-reckoned the ship's location, mistakenly reporting the ship's location as from its actual position. The error was not noticed by watch-standers. The ship was undergoing her first sea trials following the repairs, including full power, steering, and helicopter flight operation checks.
The grounding occurred at 8 p.m. about south of the Honolulu International Airport's Reef Runway. No one was injured and no fuel spilled. The grounding was in full view of commercial aircraft landing and departing from the nearby airport, causing embarrassment to the Navy.
The cruiser has a draft of and ran hard aground on a sand and rock ledge in an estimated 14 to 22 feet (5–7 m) of water. The salvage ship made three unsuccessful efforts to pull "Port Royal" off the sandbar on Friday, Saturday, and Sunday (6–8 February), despite and offloading of fuel and water, of raw sewage, and of crew members.
According to the U.S. Pacific Fleet, the ship ran aground while moving very slowly as she transferred shore-based aviation assessment officials to a smaller boat to take them to shore. The oil recovery ship "Clean Islands" was behind the ship to clean up oil spills. Rear Admiral Dixon R. Smith, the commander of Navy Region Hawaii and the Naval Surface Group Middle Pacific, served as the on-scene commander.
Recovery.
On 9 February 2009, "Port Royal" was pulled off the rock and sand shoal at around 2 a.m. after crews removed another 500 tons of water and 100 tons of anchors and other equipment to lighten the vessel. The removal by a salvage ship and seven tug boats took about 40 minutes. No one was injured during the recovery effort, according to Rear Admiral Joe Walsh, the U.S. Pacific Fleet deputy commander. Smith relieved commanding officer Captain John Carroll of his duties pending investigation. Carroll had been commanding officer of "Port Royal" since October 2008. Captain John Lauer, an official in Smith's Naval Surface Group Middle Pacific, temporarily assumed command.
The ship had suffered heavy damage to the underwater bow sonar dome and to its propellers and propeller shafts in the incident, and it was drydocked for repairs. Captain Neil Parrott presided over the investigation into the grounding.
Damage assessment and repair.
Once the raw sewage dumped by the ship had dissipated, divers from the Hawai'i Department of Land and Natural Resources examined the site and discovered that the grounding had damaged the coral reef. The Hawaiian divers, with help from Navy divers, began mapping the damage to ascertain the extent of work required to repair the coral. As of 12 February 2009, several of the cruiser's propeller blade tips had yet to be recovered from the ocean floor. Laura Thielen, chairwoman of the Hawaii state Board of Land and Natural Resources, told the United States Navy in a letter in April 2009 that the grounding had damaged between six and of the reef and that the "main injury scar" covered about . She added that the grounding may have damaged the habitat of green turtles.
On 18 February 2009, the ship entered Dry Dock Number 4 at Pearl Harbor for repair to the ship's shafting, running gear, propellers, painting of the underwater hull, replacement of the bow sonar dome and its internal elements, and repairs to damaged tanks and superstructure cracks. The Navy estimated that repairs would cost between $25 and $40 million and would be completed by September 2009. The "Honolulu Advertiser" reported that a shipyard worker had said that no work had been done to repair the warship as of 12 April 2009. The newspaper reported that its attempts to obtain information on the status of the warship had received short shrift or had not been answered by the Navy.
As of the end of July 2009, most of the repairs to the ship had been completed. Structural problems occurred in rebuilding the sonar dome, the area of the ship most heavily damaged in the grounding. Also, the struts that support the propulsion shafts were found to be out of alignment by a small but critical amount. The repairs were expected to be completed in September and the ship was expected to return to operation in October. The ship deployed for the first time since the grounding in June 2011. The cruiser departed on an eight-month deployment to the Western Pacific and Middle-East.
Acting on a request from the state of Hawaii to repair the damage to the coral habitat, the Navy hired divers from AECOM, Sea Engineering and CSA International, Inc. Work to repair the damaged reef began the last week of April 2009. At a cost of $7 million, by 27 June 2009 the divers had collected 5,400 loose coral colonies and reattached them to the reef using cement and plaster of Paris. The divers also removed of rubble. The Navy planned to conduct further repair work on the reef between October and December 2009 but this work was later suspended. The Navy reports that environmental experts have advised them that reattaching further coral to the reef would do more harm than good.
Disciplinary actions and investigation findings.
On 2 June 2009, the Navy disciplined four "Port Royal" officers for the grounding. In a hearing presided over by Vice Admiral Samuel J. Locklear, commander of the United States Third Fleet, Captain John Carroll was given non-judicial punishment for "dereliction of duty and improper hazarding of a vessel." "Port Royal" Executive Officer Commander Steve Okun was also given non-judicial punishment for dereliction of duty at the same hearing. In a separate hearing, Rear Admiral Dixon Smith, commander of Navy Region Hawaii and Naval Surface Group Middle Pacific, imposed non-judicial punishment on two other, unnamed "Port Royal" officers and an enlisted seaman for dereliction of duty and improper hazarding of a vessel. The Navy refused to provide further details of the punishments the sailors received.
The U.S. Navy safety investigation into the accident, not intended for public release but which was obtained by the "Honolulu Advertiser" in July 2009, listed several contributing factors for the grounding. The factors included a misinterpreted navigation system, a sleep-deprived commanding officer, faulty equipment and an inexperienced and dysfunctional bridge team.
The report stated that Carroll had only 4½ hours of sleep in the 24 hours prior to the grounding, and only 15 hours of sleep during the previous three days. Also, he was at sea after a five-year break in sea command duty. Carroll had directed that the aviation assessment personnel aboard the cruiser be returned to shore in a small boat just before the grounding occurred.
The report found that the ship's fathometer, which measures water depth, was broken, as well as both radar repeaters on the cruiser's bridge. Some time before the grounding, the ship switched navigation systems from a Global Positioning System, called the Voyage Management System, to a gyroscope. The switch caused a discrepancy in the ship's reported position. Audible alarm bells triggered by the discrepancy were disregarded by the ship's crew. During the small-boat transfer, the cruiser's operations officer took a binocular bearing to the harbor landing from the boat deck and noted the position discrepancy, but was unable to correct the ship's course in time. Shortly thereafter, the ship ran soft aground, but then quickly was forced hard aground by the force of the waves.
The report concluded that in spite of the equipment and navigation systems failures, there were enough working sensors and visual clues to prevent the grounding. The report found that the ship's navigation evaluator lost situational awareness and that the "Bridge watch team, navigation, and (Combat Information Center) team did not work together to assess situation and keep the ship from standing into danger." Qualified lookouts were on board for watch duty the night of the grounding, but they were working in the mess as food service attendants and were not allowed to assume the watch. Furthermore, set and drift were not calculated.
The report stated that the cruiser had been rushed out of dry dock, with some work scaffolding removed from the ship only 30 minutes before the cruiser departed for the ocean trials. Also, the quartermaster of the watch was inexperienced and lacked training, having stood three months of watch on a deployment a year earlier, but could not plot fixes in near-shore waters. The report recommended a supervisory-level navigation course, as well as an "operational pause" of at least 96 hours between shipyard availabilities and sea trials to ensure crews were adequately rested and prepared for underway operations. Captain W. Scott Gureck, a spokesman for U.S. Pacific Fleet, declined to comment on the investigation's findings.
The report was created by the Naval Safety Investigation Board but has been classified by the Navy Judge Advocate General as a "Dual Purpose Investigation". The Navy will therefore not release the report under the Freedom of Information Act. Reportedly, the Navy does not want to publicly discuss what caused the grounding because of threatened legal action by the state of Hawaii.
Aftermath.
"Port Royal" left dry dock at Pearl Harbor on 24 September 2009 for final repairs and assessment before being returned to duty. While in dry dock, technicians from BAE Systems and the Navy replaced the cruiser's sonar dome, reinstalled rudders, and made structural repairs to the ship's tanks, superstructure, and underwater hull. In addition, four sections of shafting were replaced, struts that support the propulsion shafts were realigned, and the underwater hull was repainted with blue antifouling paint.
In February 2011, the Navy and the state of Hawaii announced that they had reached a settlement on the damage caused by the grounding. The Navy agreed to pay Hawaii $8.5 million. The amount was in addition to the $6.5 million already spent by the Navy in efforts to repair the reef. "This settlement agreement recognizes the State of Hawaii's loss of a natural resource and takes into account the U.S. Navy's unprecedented efforts to restore the reef where USS "Port Royal" ran aground," said Rear Admiral Timothy Giardina, U.S. Pacific Fleet deputy commander. In response, William J. Aila, State of Hawaii Department of Land and Natural Resources interim chairperson, stated, "We believe the Navy has done the right thing by acknowledging its responsibility, working cooperatively with the state to restore the reef, and completing a settlement that will provide funding for protection of the state's marine resources."
After $40 million in repairs, the cruiser deployed for the first time since the grounding in June 2011. The cruiser departed Pearl Harbor on a seven-month deployment to the Western Pacific and Middle East. Said Smith, commander of Navy Region Hawaii and Naval Surface Group Middle Pacific, of the grounding incident upon the departure of the ship, "I've put it behind me. We've moved forward. The ship has moved forward. It was an unfortunate incident that we all learned from."
Navy command was said to have lost confidence that the vessel had been restored to seaworthiness, and, because of that, the ship was included on a list of seven cruisers slated for early retirement. Decommissioning in anticipation of eventual dismantlement was set for 31 March 2013. However, in answer to queries by Congress, the Naval Sea Systems Command (NAVSEA), in a report sent to Congress in May 2013, reported that the condition of the ship was comparable to certain other cruisers in the same class and that the effects of the grounding might not have been as severe as had been previously thought.


General time- and transfer constant analysis

The general time- and transfer-constants (TTC) analysis is the generalized version of the Cochran-Grabel (CG) method, which itself is the generalized version of zero-value time-constants (ZVT), which in turn is the generalization of the open-circuit time constant method (OCT). While the other methods mentioned provide varying terms of only the denominator of an arbitrary transfer function, TTC can be used to determine every term both in the numerator and the denominator. Its demoninator terms are the same as that of Cochran-Grabel method, when stated in terms of time-constants (when expressed in Rosenstark notation). however, the numerator terms are determined using a combination of transfer constants and time constants, where the time constants are the same as those in CG method. Transfer constants are low frequency ratios of the output variable to input variable under different open- and short-circuited active elements.
In general, a transfer function (which can characterize gain, admittance, impedance, trans-impedance, etc. based on the choice of the input and output variables) can be written as:
The denominator terms.
The first denominator term formula_2 can be expressed as the sum of zero value time constants (ZVTs):
where formula_4 is the time constant associated with the reactive element formula_5 when all the other sources are zero valued (hence the superscript '0'). Setting a capacitor value to zero corresponds to an open circuit, while a zero-valued inductor is a short circuit. So for calculation of the formula_4, all other capacitors are open circuited and all other inductors are short-circuited. This is the essence of ZVT method, which reduces to OCT when only capacitors are involved. All independent sources are also zero valued during the time constant calculations (voltage sources short circuited and current source open circuited). In this case, if the element in question (element formula_5) is a capacitor, the time constant is given by
and when element formula_5 is an inductor is it given by:
where in both cases, the resistance formula_11, is the resistance seen by elements formula_5 (denoted by subscript), when all the other elements are zero valued (denoted by the zero superscript).
The second order denominator term is equal to:
where the second form is the often used shorthand notation for a sum that does not repeat permutations (e.g., only one of the permutations formula_14 and formula_15 are counted).
The second order time constant, formula_16, is simply the time constant associated with the reactive element formula_5 (where subscript always denotes the index of element in question), when element formula_18 is infinite valued. In this notation the superscript always denotes the index of the element (or elements) being infinite valued, with superscript zero implying all elements are zero valued. Infinite valued capacitors are short-circuits, while infinite value inductor are open circuits.
In general, any denominator terms can be expressed as:
where formula_20 is the time constant of associated with element formula_5, when all the elements with an index in the superscript (i.e., formula_22) are infinite valued (shorted capacitors and opened inductors). Usually the higher order time constants involve simpler calculation, as there are more infinite valued elements involved during their calculations.
The numerator terms.
The major addition in the TTC over the Cochran-Grabel method is its ability to calculate all the numerator terms in a similar fashion using the same time-constants used for the denominator calculation in conjunction with transfer constants, denoted as formula_23. Transfer constants are low frequency gains (or in general ratios of the output to input variables) under different combinations of reactive elements being zero and infinite valued. The notation uses the same convention, with all the elements whose indexes appear in the superscript of formula_24, being infinite valued (shorted capacitors and opened inductors) and all unlisted elements zero valued. The zeroth order transfer constant formula_25 denotes the ratio of the output to input when all elements are zero-valued (hence the superscript of 0).
Using the time constants and transfer constants all terms of the numerator can be calculated. In particular:
which is the transfer constant when all elements are zero valued (e.g., dc gain).
The first order numerator term can be expressed as the sum of the products of first order transfer constants formula_27 and their associated zero value time constants, formula_4,
where transfer constant, formula_27, is the ratio of the output to input when element formula_5 is infinite valued and all others are zero valued. Similarly, the second order numerator term is given by
where, again, transfer constant, formula_33, is the transfer constant when both element formula_5 and formula_18 are infinite valued (all else zero valued).
In general, the formula_36th numerator term is given by:
This allows for full calculation of any transfer function to any degree of accuracy by generating sufficient number of numerator and denominator terms using the above expressions.


Olympic Arms OA-93

The OA-93 is an AR-15 derivative pistol manufactured by Olympic Arms. Lacking a buttstock or buffer tube, the OA-93 disperses recoil through a specially designed flat top upper receiver similar to the Armalite AR-18. However, the passage of the 1994 Crime Bill required Olympic Arms to perform modifications to the basic design to continue selling them:
The first revision to the OA-93 was the OA-96 in which a 30-round ammunition well is pinned and welded in place so that it cannot be detached. In addition, the OA-96 has a button in the rear which opens the upper receiver and can then be loaded via stripper clips.
The second revision followed two years later. OA-98 used a detachable magazine but the body was skeletonized to reduce the weight below the 50 ounce restriction to allow the OA-98 to have one more feature to be compliant with the 1994 Crime Bill.
A piston driven carbine based on the pistol was made in 1993 and after the expiration of the Federal Assault Weapons Ban from 2004 to 2007.


Pickup (music technology)

A pickup is a transducer that captures or senses mechanical vibrations produced by musical instruments, particularly stringed instruments such as the electric guitar, and converts these to an electrical signal that is amplified using an instrument amplifier to produce musical sounds through a loudspeaker in a speaker enclosure. The signal from a pickup can also be recorded directly.
Most electric guitars and electric basses use magnetic pickups. Acoustic guitars, upright basses and fiddles often use a piezoelectric pickup.
Magnetic pickups.
A typical magnetic pickup is a transducer (specifically a variable reluctance sensor) that consists of one or more permanent magnets (usually alnico or ferrite) wrapped with a coil of several thousand turns of fine enameled copper wire. The magnet creates a magnetic field which is focused by the pickup's pole piece or pieces. The permanent magnet in the pickup magnetises the guitar string above it. So the string is, in essence, a magnet itself and its magnetic field is in alignment with that of the permanent magnet that magnetized it. When the string is plucked, the magnetic field around it moves up and down with the string. This moving magnetic field induces a current in the coil of the pickup as described by Faraday's law of induction. Typical output might be 100–300 millivolts.
The pickup is connected with a patch cable to an amplifier, which amplifies the signal to a sufficient magnitude of power to drive a loudspeaker (which might require tens of volts). A pickup can also be connected to recording equipment via a patch cable.
The pickup is most often mounted on the body of the instrument, but can be attached to the bridge, neck or pickguard. The pickups vary in power, and they vary in style. Some pickups can be single coil, while other pickups can be double coil humbuckers. The pickup is one of the most important aspect to distinguishing a guitar's sound. Most guitar models have a distinction in pickups, which act as a new selling point for guitar companies.
Construction.
Pickups have magnetic polepieces (one or two for each string, with the notable exceptions of rail and lipstick tube pickups), approximately centered on each string. (The standard pickups on the Fender Jazz Bass and Precision Bass have two polepieces per string, to either side of each string.)
On most guitars, the strings are not fully parallel: they converge at the nut and diverge at the bridge. Thus, bridge, neck and middle pickups usually have different polepiece spacings on the same guitar.
There are several standards on pickup sizes and string spacing between the poles. Spacing is measured either as a distance between 1st to 6th polepieces' centers (this is also called "E-to-E" spacing), or as a distance between adjacent polepieces' centers.
Output.
Some high-output pickups employ very strong magnets, thus creating more flux and thereby more output. This can be detrimental to the final sound because the magnet's pull on the strings (called string capture) can cause problems with intonation as well as damp the strings and reduce sustain.
Other high-output pickups have more turns of wire to increase the voltage generated by the string's movement. However, this also increases the pickup's output resistance/impedance, which can affect high frequencies if the pickup is not isolated by a buffer amplifier or a DI unit.
Pickup sound.
The turns of wire in proximity to each other have an equivalent self-capacitance that, when added to any cable capacitance present, resonates with the inductance of the winding. This resonance can accentuate certain frequencies, giving the pickup a characteristic tonal quality. The more turns of wire in the winding, the higher the output voltage but the lower this resonance frequency.
The arrangement of parasitic resistances and capacitances in the guitar, cable, and amplifier input, combined with the inductive source impedance inherent in this type of transducer forms a resistively-damped second-order low-pass filter, producing a non-linearity effect not found in piezeoelectric or optical transducers. Pickups are usually designed to feed a high input impedance, typically a megohm or more, and a low-impedance load increases attenuation of higher frequencies. Typical maximum frequency of a single-coil pickup is around 5 kHz, with the highest note on a typical guitar fretboard having a fundamental frequency of 1.17 kHz.
Humbuckers.
Single-coil pickups act like a directional antenna and are prone to pick up mains hum—nuisance alternating current electromagnetic interference from electrical power cables, power transformers, fluorescent light ballasts, video monitors or televisions—along with the musical signal. Mains hum consists of a fundamental signal at a nominal 50 or 60 Hz, depending on local current frequency, and usually some harmonic content.
To overcome this, the humbucking pickup was invented by Joseph Raymond "Ray" Butts (for Gretsch), while Seth Lover also worked on one for Gibson. Who developed it first is a matter of some debate, but Butts was awarded the first patent () and Lover came next ().
A humbucking pickup is composed of two coils, with each coil wound reverse to the other. Each set of six magnetic poles is also opposite in polarity. Since ambient hum from electrical devices reaches the coils as common-mode noise, it induces an equal voltage in each coil, but 180 degrees out of phase between the two voltages. These effectively cancel each other, while the signal from the guitar string is doubled.
When wired in series, as is most common, the overall inductance of the pickup is increased, which lowers its resonance frequency and attenuates the higher frequencies, giving a less trebly tone (i.e., "fatter") than either of the two component single-coil pickups would give alone.
An alternative wiring places the coils in "buck" parallel, which has a more neutral effect on resonant frequency. This pickup wiring is rare, as guitarists have come to expect that humbucking pickups 'have a sound', and are not so neutral. On fine jazz guitars, the parallel wiring produces significantly cleaner sound, as the lowered source impedance drives capacitive cable with lower high frequency attenuation.
A "side-by-side" humbucking pickup senses a wider section of each string than a single-coil pickup. By picking up a larger portion of the vibrating string, more lower harmonics are present in the signal produced by the pickup in relation to high harmonics, resulting in a "fatter" tone. Humbucking pickups in the narrow form factor of a single coil, designed to replace single-coil pickups, have the narrower aperture resembling that of a single coil pickup. Some models of these single-coil-replacement humbuckers produce more authentic resemblances to classic single-coil tones than full-size humbucking pickups of a similar inductance.
Notation.
Most electric guitars have two or three magnetic pickups. A combination of pickups is called a "pickup configuration", usually notated by writing out the pickup types in order from bridge pickup through mid pickup(s) to neck pickup, using “S” for single-coil and “H” for humbucker. Typically the bridge pickup is known as the lead pickup, and the neck pickup is known as the rhythm pickup.
Common pickup configurations include:
Less frequently found configurations are:
Examples of rare configurations that only a few particular models use include:
Piezoelectric pickups.
Sensors.
The piezoelectric pickup contains a piezo crystal, which converts the vibrations directly to a changing voltage.
Many semi-acoustic and acoustic guitars, and some electric guitars and basses, have been fitted with piezoelectric pickups instead of, or in addition to, magnetic pickups. These have a very different sound, and also have the advantage of not picking up any other magnetic fields, such as mains hum and feedback from monitoring loops. In hybrid guitars, this system allows switching between magnetic pickup and piezo sounds, or simultaneously blending the output. Solid bodied guitars with only a piezo pickup are known as silent guitars, which are usually used for practicing by acoustic guitarists. Piezo pickups can also be built into electric guitar bridges for conversion of existing instruments.
Most pickups for bowed string instruments, such as cello, violin, and double bass, are piezoelectric. These may be inlaid into the bridge, laid between the bridge feet and the top of the instrument, or, less frequently, wedged under a wing of the bridge. Some pickups are fastened to the top of the instrument with removable putty.
Preamps.
Piezoelectric pickups have a very high output impedance and appear as a capacitance in series with a voltage source. They therefore often have an instrument-mounted buffer amplifier fitted to maximize frequency response.
The piezo pickup gives a very wide frequency range output compared to the magnetic types and can give large amplitude signals from the strings. For this reason, the buffer amplifier is often powered from relatively high voltage rails (about ±9 V) to avoid distortion due to clipping. A less linear preamp (like a single-FET amplifier) might be preferable due to softer clipping characteristics. Such an amplifier starts to distort sooner, which makes the distortion less "buzzy" and less audible than a more linear, but less forgiving op-amp. However, at least one study indicates that most people cannot tell the difference between FET and op-amp circuits in blind listening comparisons of electric instrument preamps, which correlates with results of formal studies of other types of audio devices. Sometimes, piezoelectric pickups are used in conjunction with magnetic types to give a wider range of available sounds.
For early pickup devices using the piezoelectric effect, see phonograph.
Other transducers.
Some pickup products are installed and used similarly to piezoelectric pickups, but use different underlying technology, for instance electret or condenser microphone technology.
Double systems pickups.
There are basically four principles used to convert sound into an alternating current, each with their pros and cons:
An amplification system with two transducers combines the qualities of both. A combination of a microphone and a piezoelectric pickup typically produces better sound quality and less sensitivity to feedback, as compared to single transducers. However, this is not always the case. A less frequently used combination is a piezoelectric and a magnetic pickup. This combination can work well for a solid sound with dynamics and expression. Examples of a double system amplifier are the Highlander iP-2, the Verweij VAMP or the LR Baggs dual source and the D-TAR Multisource.
Multi-transducer pickups.
Hexaphonic pickups (also called "divided pickups" and "polyphonic pickups") have a separate output for each string ("Hexaphonic" assumes six strings, as on a guitar). This allows for separate processing and amplification for each string. It also allows a converter to sense the pitch coming from individual string signals for producing note commands, typically according to the MIDI (musical instrument digital interface) protocol. A hexaphonic pickup and a converter are usually components of a guitar/synthesizer.
Such pickups are uncommon (compared to normal ones), and only a few notable models exist, like the piezoelectric pickups on the Moog Guitar. Hexaphonic pickups can be either magnetic or piezoelectric or based on the condensor principle like electronicpickups
Optical.
Optical pickups are a fairly recent development that work by sensing the interruption of a light beam by a vibrating string. The light source is usually an LED, and the detector is a photodiode or phototransistor. These pickups are completely resistant to magnetic or electric interference and also have a very broad and flat frequency response, unlike magnetic pickups.
Optical pickup guitars were first shown at the 1969 NAMM in Chicago, by Ron Hoag.
In 2000, Christopher Willcox, founder of LightWave Systems, unveiled a new beta technology for an optical pickup system using infrared light. In May 2001, LightWave Systems released their second generation pickup, dubbed the "S2."
Active and passive pickups.
Pickups can be either active or passive. Pickups, apart from optical types, are inherently passive transducers. "Passive" pickups are usually wire-wound around a magnet, and are the most common type used. They can generate electric potential without need for external power, though their output is relatively low, and the harmonic content of output depends greatly on the winding.
"Active" pickups incorporate electronic circuitry to modify the signal. Active circuits are able to filter, attenuate or boost the signal from the pickup. The main disadvantage of an active system is requirement of a battery power source to operate the preamp circuitry. Batteries limit circuit design and functionality, in addition to being inconvenient to the musician. The circuitry may be as simple as a single transistor, or up to several operational amplifiers configured as active filters, active EQ and other sound-shaping features. The op amps used must be of a low-power design to optimize battery life, a design restriction that limits the dynamic range of the circuit. The active circuitry may contain audio filters, which reduce the dynamic range and mildly distort certain ranges. High-output active pickup systems also have an effect on an amplifier's input circuit.
Stereo and multiple pickups with individual outputs.
Rickenbacker was the first manufacturer to market stereo instruments (guitars and basses). Their proprietary "Ric-O-Sound" circuitry has two separate output jacks, allowing the musician to send each pickup to its own audio chain (effects device, amplifier, mix console input).
Teisco produced a guitar with a stereo option. Teisco divided the two sections in the upper three strings and the lower three strings for each individual output.
The Gittler guitar was an experimental guitar with six pickups, one for each string.
Gibson created the HD.6X Pro guitar that captures a separate signal for each individual string and sends them to an onboard analog/digital converter, then out of the guitar via Ethernet cable.


Michel Bernard (administrator)

Michel Bernard, born the 1st of March 1943 at Bourges, graduate of École Polytechnique (promotion 1964) and École nationale de l'aviation civile (promotion 1967), was the head of the "Agence nationale pour l'emploi" from 1995 to 2005.
Biography.
Michel Bernard has performed a career in French administration and national companies.
He starts his career in 1969 at the "service technique de la navigation aérienne" (air navigation technical department) then becomes head of the "centre en route de la navigation aérienne Nord" (North en route air navigation center) in 1978.
He is promoted Directeur général de l'aviation civile in 1993.
During this period, he was director of human resources at Snecma, Air France director and Air Inter President from November 1993 until March 1995, when he resigned, denouncing the "backward-looking categorical protection" which are attached the unions.
He is head of the "ANPE" from 1995 till 2005 (his predecessor was Michel Bon and his successor Christian Charpy).
Since October 1995, Michel Bernard is head of the board of directors of the "Fonds d'aide et de soutien pour l'intégration et la lutte contre les discriminations" (Aid funds and support for integration and the fight against discrimination).
Michel Bernard is the current President of the "cultures du coeur" ("hearth culture") association which works to fight against social exclusion by promoting access to cultural and sporting events.


Parson magneton


Dix (steamboat)

The steamboat Dix operated from 1904 to 1906 as part of the Puget Sound Mosquito Fleet. She was sunk in a collision which remains one of the most serious transportation accidents in the state of Washington to this day.
In May 2011, it was reported that wreckage likely to be that of the "Dix" had been confirmed off Seattle's Alki Point.
Construction.
"Dix" was built in 1904 at the Tacoma yard of Crawford and Reid.. "Dix" was long, on the beam, depth of hold, and rated at 130 tons. Later, given her tragic end, it was recalled, perhaps superstitiously, that the launching of "Dix" was a failure. The vessel had simply refused to move down the ways at Crawford and Reid, and had to be hauled into the water the next day by Captain Sutter in command of Tacoma Tug and Barge’s "Fairfield".
"Dix" was purpose-built for one route only, the run across Elliott Bay from Seattle to Alki Point, then the main recreation area for Seattle. Her owners were A.B.C. Dennison and W.L. Dudley, doing business as the Seattle and Alki Point Transportation Company. She was lightly built, and apparently top-heavy, as the steamboat inspectors twice refused to issue her a seaworthiness certificate, only relenting when her builders installed 7 tons of gravel ballast in her hull and 5 tons of iron weights bolted to her keel. Even so, she was said to be difficult to handle.
Operations.
Dennison and Dudley put "Dix" on the intended Seattle-Alki route. In summer service with their other steamer "Manette" the two boats made nineteen trips daily. During the legislative session in early 1905, "Dix" was placed on the Olympia-Tacoma route. The fast sternwheeler "Greyhound" was already on that run and there wasn’t much business left over, so in January 1905 "Dix" was returned to the Alki run.
Sinking of "Dix".
On November 18, 1906, "Dix" was not on her customary Alki route, but was acting as a relief boat for "Monticello" on the Seattle-Port Blakeley run. She left Seattle with about 77 passengers. Her captain, Percy Lermond, tasked with collecting fares, was absent from the pilot house, leaving the mate Charles Dennison in charge. Theoretically fare collection was a job for the purser, but on the smaller vessels, it was customary for the master to perform this function.
The evening was calm and somewhat clear, and as the vessel steamed west past Alki Point into the open Sound, Captain Lermond went to his quarters behind the pilot house to tally the fares. Off Duwamish Head, "Dix" approached near the Alaska Coast Company steamer "Jeanie" and then mate Dennison (who it turns out was unlicensed) inexplicably turned the vessel directly into "Jeanie"s path. "Jeanie "was ten times the size of "Dix" and loaded with iron ore. Even though "Jeanie" had already reversed her engines, and was barely under steerage way, the impact was sufficient, given the much greater weight of "Jeanie", to cause "Dix" to heel sharply over on her port side. She quickly filled with water, rolled over, and sank in . Captain Lermond described the terrifying scene:
Impact of sinking.
The first vessel on the scene was , whose master, Capt. Cyprian T. Wyatt (1877-1952) and chief engineer, E.L. Franks, picked up the first survivors and took them to Port Blakeley. The shock of the survivors was great, as a newspaper account of the time showed:
Reports of the number of passengers lost vary; "The New York Times", having received a dispatch from Portland, Oregon about the sinking, reported the number lost as 40; Years later, in a 1913 story about "Jeanie"s loss off Calvert Island, the "Times" reported the number of passengers lost by the sinking of "Dix" as 54. A 2011 "Seattle Times" article said the number was "as many as 45", when another source has it as over 45 people, including Charles Dennison. Mrs. Byler’s sons, Charles and Christian, and their sister, Lillian, were all trapped below deck and taken down when the ship sank.
The chief engineer, George F. Parks also drowned. The wreck was sunk so deep that salvage operations were impossible. No bodies were ever recovered; the people were trapped inside and went down with her. Most of the "Dix" victims were from Port Blakeley, and the place was hit hard, that night in the little town being described as "running of a gauntlet of shrieks and moans of grief-stricken wives and mothers ..." Work stopped briefly at the huge Port Blakely Lumber Mill for the first time in the mill’s history.
Captain Lermond was one of the survivors, indeed he died only in 1959, at the age of 90 years. Following the "Dix" sinking, his master’s and pilot licenses were revoked. The Steamboat Inspection Service found "Dix" totally at fault for failure to keep an efficient lookout and that the captain, who had been acting as both master and fare collector at the time of the accident, was found to have negligently relinquished his control of the steamer to an unqualified person. Captain Lermond had apparently failed to protest the requirement he collect fares for fear of his job.
Although his license was reinstated a year later, Captain Lermond served in command of tugs only for the rest of his career until 1933, never again commanding a passenger vessel.
Though the fault was placed with "Dix" and captain Lermond it was found during the investigation that "Jeanie" was navigating in violation of law with only one engineer, the first assistant, on the engine; without the knowledge of the ship's master. Up until then, with the significant exception of , the steamboats had enjoyed a good reputation for safety, at least by the standards of the time. The circumstances of the loss of "Dix" were all the more shocking to the people on the Sound, who depended on the steamboats for their basic transportation.
In 1973, a memorial to "Dix" was dedicated in a small park at Duwamish Head.


Helicopter dynamics

Helicopter dynamics is a field within aerospace engineering concerned with theoretical and practical aspects of helicopter flight. Its purpose is the knowledge of forces and torques which appear in helicopter flight.
History.
The development of helicopter dynamics arose from the necessity to improve the first helicopters.
Measuring dynamics of helicopter rotors is very challenging due to wiring and data transmission problems. Researchers have recently used stereophotogrammetry to measure dynamics of a helicopter rotor during hover


Canon RF lens mount

The Canon RF lens mount is an interchangeable-lens mount developed by Canon for its full-frame mirrorless interchangeable-lens cameras, and featured first by the EOS R, followed by the EOS RP. The RF mount was announced in September 2018.
The RF mount allows for the use of Canon EF and EF-S mount lenses using one of three Canon-made lens adapters.
Details.
Canon full-frame cameras have used the EF lens mount since 1987. In comparison with that mount, the RF mount's inner diameter is the same at 54 mm. The RF mount's flange focal distance at 20 mm is much shorter than that of the Canon EF and EF-S mounts at 44 mm. The EF-M mount has a flange focal distance of 18 mm.
An EF-EOS R lens adapter enables Canon EF, EF-S, TS-E and MP-E lenses to be used on cameras that have the RF mount. The three adapters have differing features:
The EOS R is a 30 megapixel (6720 × 4480) full-frame camera. If an EF-EOS R Mount Adapter is used with it to mount an EF-S lens, the camera will function as an 11.6 megapixel (4176 × 2784) crop camera.
Lenses.
At the time Canon announced its first R-series body, it announced four new RF-mount lenses:
In conjunction with the February 2019 announcement of the entry-level full-frame EOS RP, Canon announced that six additional lenses would be released by the end of that year, although it did not indicate release dates for any of them:
In 2020, Canon has introduced 7 new RF mount lenses:
In 2021, Canon has introduced 3 new RF mount lenses:
RF-mount lenses are not compatible with EF, EF-S or EF-M mount camera bodies.
Compatibility.
The cameras that can use the RF mount are:


Drying

Drying is a mass transfer process consisting of the removal of water or another solvent by evaporation from a solid, semi-solid or liquid. This process is often used as a final production step before selling or packaging products. To be considered "dried", the final product must be solid, in the form of a continuous sheet (e.g., paper), long pieces (e.g., wood), particles (e.g., cereal grains or corn flakes) or powder (e.g., sand, salt, washing powder, milk powder). A source of heat and an agent to remove the vapor produced by the process are often involved. In bioproducts like food, grains, and pharmaceuticals like vaccines, the solvent to be removed is almost invariably water. Desiccation may be synonymous with drying or considered an extreme form of drying.
In the most common case, a gas stream, e.g., air, applies the heat by convection and carries away the vapor as humidity. Other possibilities are vacuum drying, where heat is supplied by conduction or radiation (or microwaves), while the vapor thus produced is removed by the vacuum system. Another indirect technique is drum drying (used, for instance, for manufacturing potato flakes), where a heated surface is used to provide the energy, and aspirators draw the vapor outside the room. In contrast, the mechanical extraction of the solvent, e.g., water, by filtration or centrifugation, is not considered "drying" but rather "draining".
Drying mechanism.
In some products having a relatively high initial moisture content, an initial linear reduction of the average product moisture content as a function of time may be observed for a limited time, often known as a "constant drying rate period". Usually, in this period, it is surface moisture outside individual particles that is being removed. The drying rate during this period is mostly dependent on the rate of heat transfer to the material being dried. Therefore, the maximum achievable drying rate is considered to be heat-transfer limited. If drying is continued, the slope of the curve, the drying rate, becomes less steep (falling rate period) and eventually tends to become nearly horizontal at very long times. The product moisture content is then constant at the "equilibrium moisture content", where it is, in practice, in equilibrium with the dehydrating medium. In the falling-rate period, water migration from the product interior to the surface is mostly by molecular diffusion, i,e. the water flux is proportional to the moisture content gradient. This means that water moves from zones with higher moisture content to zones with lower values, a phenomenon explained by the second law of thermodynamics. If water removal is considerable, the products usually undergo shrinkage and deformation, except in a well-designed freeze-drying process. The drying rate in the falling-rate period is controlled by the rate of removal of moisture or solvent from the interior of the solid being dried and is referred to as being "mass-transfer limited". This is widely noticed in hygroscopic products such as fruits and vegetables, where drying occurs in the falling rate period with the constant drying rate period said to be negligible.
Methods of drying.
The following are some general methods of drying:
Applications of drying.
Food.
Foods are dried to inhibit microbial development and quality decay. However, the extent of drying depends on product end-use. Cereals and oilseeds are dried after harvest to the moisture content that allows microbial stability during storage. Vegetables are blanched before drying to avoid rapid darkening, and drying is not only carried out to inhibit microbial growth, but also to avoid browning during storage. Concerning dried fruits, the reduction of moisture acts in combination with its acid and sugar contents to provide protection against microbial growth. Products such as milk powder must be dried to very low moisture contents in order to ensure flowability and avoid caking. This moisture is lower than that required to ensure inhibition to microbial development. Other products as crackers are dried beyond the microbial growth threshold to confer a crispy texture, which is liked by consumers.
Non-food products.
Among non-food products, some of those that require considerable drying are wood (as part of timber processing), paper, flax, and washing powder. The first two, owing to their organic origins, may develop mold if insufficiently dried. Another benefit of drying is a reduction in volume and weight.
Sludges and fecal materials from sanitation processes.
In the area of sanitation, drying of sewage sludge from sewage treatment plants, fecal sludge or feces collected in urine-diverting dry toilets (UDDT) is a common method to achieve pathogen kill, as pathogens can only tolerate a certain dryness level. In addition, drying is required as a process step if the excreta based materials are meant to be incinerated.


Water Park station

Water Park station () is a station of the Incheon Airport Maglev in Unseo-dong, Jung District, Incheon, South Korea.


Sizzix

Sizzix is the brand name of a product range of home die-cutting machines and embossing machines manufactured by Ellison. The machines are used for cutting materials such as paper, fabric, vellum, metal and other materials that scissors can cut. The products are most commonly used by crafters, quilters and sewers for scrapbooking, cardmaking, home décor, jewelry making, and other arts and crafts activities.
Sizzix has also seen success in its partnership with about 20 artists who have opened the company up to new markets and categories.
Machines.
The Sizzix product range launched in 2001 as an evolution of the first patented die-cutting machine, the "Ellison LetterMachine", created in 1977. Along with the die-cutting machines, the Sizzix product range also includes steel-rule dies, chemically-etched dies, embossing folders and storage folders.
Awards.
The Golden Press Kit Award was awarded to Sizzix at the Craft and Hobby Association (CHA) Summer 2012 trade show.
The "BIGkick" was awarded the 2008 Reader's Choice Winner in the February 2009 issue of Creating Keepsakes magazine in the Die Cut Equipment category.


Delta and Dawn

Delta and Dawn, also known as the Delta whales, were two humpback whales, a mother and her calf, which entered San Francisco Bay in early May 2007. They swam up the Sacramento River approximately upstream from the Golden Gate, about further inland than Humphrey the Whale had gone two decades earlier. Under the Endangered Species Act, California state officials were required to rescue the animals. Their journey was thought to be the longest freshwater incursion by humpback whales.
Efforts to save the whales.
Staff from the Marine Mammal Center, researchers, Coast Guard personnel, and volunteers tried several methods to coax Delta and Dawn back downriver. The Marine Mammal Center was appointed by the California Office of Emergency Services as the lead rescue agency. Officials played recordings of the sounds of other humpback whales feeding and socializing to lure them, and banged on submerged metal pipes and sprayed high-powered blasts of water to repel them, but it is not clear whether any of these were particularly effective. There was heightened concern for the whales' well-being this time, because both of them had sizable gash wounds, most likely made from boat keel or propeller strikes. Veterinarians from the Marine Mammal Center and WHOI administered antibiotics to the whales to help heal these deep open wounds, and they took samples of skin lesions incurred during the whales' extended time away from seawater to analyze them for possible freshwater bacterial infection. This was the first time antibiotics had been administered to free swimming whales in the wild.
Return to the sea.
On May 20, after languishing for six days in the Sacramento Deep Water Ship Channel, the whales finally started moving. They were spotted the next day about downstream, just upriver from Rio Vista, where they lingered for several days, seemingly hesitant to pass under the Rio Vista Bridge. On May 27 they were on the move again and were spotted the next day another downstream in the saltier waters of Suisun Bay, just or so from the ocean, but again their circling movements seemed to indicate a reluctance to pass beneath a bridge, actually a trio of bridges this time at Benicia. On May 29, however, they again moved quickly, passing under the Benicia Bridge in the morning and swimming through the Carquinez Strait and past yet another pair of bridges. By late afternoon they had continued through San Pablo Bay and were circling just beyond the Richmond-San Rafael Bridge near Tiburon. They were last spotted at sunset that night, within of the Golden Gate Bridge and the open ocean beyond.
Naming convention.
A small controversy arose over what to call the whales as soon as they were spotted far enough upriver to warrant significant attention. Besides being called "the Wayward Whales," they were also dubbed "Momma" and "Baby", "Rio" and "Vista", and "Delta" and "Dawn" (for the Sacramento-San Joaquin River Delta and the 1970s song "Delta Dawn"). California's Lieutenant Governor, John Garamendi, was the one to bestow the last pair of names upon the whales. Their names were inspired by local media contests throughout the region.
Legacy.
The story of the wayward whales inspired Stefanie Cruz, a news anchor for Sacramento-based television station KOVR, to write a children's book based on the tale, 'Delta & Dawn: Mother and Baby Whales' Journey', which was released November 2007. The whales were also lampooned by a cartoon.


Hi-hat

A hi-hat (hihat, high-hat, etc.) is a combination of two cymbals and a pedal, all mounted on a metal stand. It is a part of the standard drum kit used by drummers in many styles of music including rock, pop, jazz, and blues. Hi-hats consist of a matching pair of small to medium-sized cymbals mounted on a stand, with the two cymbals facing each other. The bottom cymbal is fixed and the top is mounted on a rod which moves the top cymbal towards the bottom one when the pedal is depressed (a hi-hat that is in this position is said to be "closed" or "closed hi-hats").
The hi-hat evolved from a "sock cymbal", a pair of similar cymbals mounted at ground level on a hinged, spring-loaded foot apparatus. Drummers invented the first sock cymbals to enable one drummer to play multiple percussion instruments at the same time. Over time these became mounted on short stands - also known as "low-boys" - and activated by pedals similar to those used in modern hi-hats. When extended upwards roughly 3' (76 cm) they were originally known as "high sock" cymbals, which evolved over time to the familiar "high-hat" term.
The cymbals may be played by closing them together with the pedal, which creates a "chck" sound or striking them with a stick, which may be done with them open, closed, open and then closed after striking to dampen the ring, or closed and then opened to create a shimmering effect at the end of the note. Depending on how hard a hi-hat is struck and whether it is "open" (i.e., pedal not pressed, so the two cymbals are not closed together), a hi-hat can produce a range of dynamics, from very quiet "chck" (or "chick") sounds, done with merely gently pressing the pedal; this is suitable for soft accompaniment during a ballad or the start of a guitar solo, to very loud (e.g. striking fully open hats hard with sticks, a technique used in loud heavy metal music songs).
While the term hi-hat normally refers to the entire setup (two cymbals, stand, pedal, rod mechanism), in some cases, drummers use it to refer exclusively to the two cymbals themselves.
History.
Initial versions of the hi-hat were called clangers, which were small cymbals mounted onto a bass drum rim and struck with an arm on the bass drum pedal. Then came shoes, which were two hinged boards with cymbals on the ends that were clashed together. Next was the low-sock, low-boy or low-hat, pedal-activated cymbals employing an ankle-high apparatus similar to a modern hi-hat stand. A standard size was , some with heavy bells up to wide.
Hi-hats that were raised and could be played by hand as well as foot may have been developed around 1926 by Barney Walberg of the drum accessory company Walberg and Auge. The first recognized master of the new instrument was "Papa" Jo Jones, whose playing of timekeeping "ride" rhythms while striking the hi-hat as it opened and closed inspired the innovation of the ride cymbal. Another claim, published in Jazz Profiles Blogspot on August 8, 2008, to the invention of the hi-hat is attributed to drummer William "O'Neil" Spencer (b.1909-d.1944). Legendary Jazz drummer, "Philly Joe Jones" (born as Joseph Rudolph Jones, b.1923-d.1985), was quoted describing his understanding about the hi-hat history. Jones said, "I really dug O'Neil. He came to club in Philadelphia where I was working in 1943, I think it was, and talked to me about the hi-hat. I was using a foot cymbal, the low-hat. O'Neil was the one who invented the hi-hat. I believe that, man. He suggested I close the hat on '2' and '4' when playing 4/4 time. The idea seemed so right hadn't heard anyone do that before." The editor of the 2008 Jazz Profiles article made specific mention to others who are thought to invent the hi-hat, including Jo Jones, but also Kaiser Marshall. Not to take away from Papa Jones accomplishments in drumming style and technique, a 2013 Modern Drummer article credits Papa Jones with being the first to use brushes on drums and shifting time keeping from the bass drum to the hi-hat (providing a "swing-pulse focus").
Until the late 1960s, standard hi-hats were , with available as a less-common alternative in professional cymbal ranges, and smaller sizes down to restricted to children's kits. In the early 1970s, hard rock drummers (including Led Zeppelin's John Bonham) began to use hi-hats, such as the Paiste Giant Beat. In the late 1980s, Zildjian released its revolutionary Special Recording hats, which were small, heavy hi-hat cymbals intended for close miking either live or recording, and other manufacturers quickly followed suit, Sabian for example with their mini hats. In the early to mid-1990s, Paiste offered mini hi-hats as part of its Visions series, which were among the world's smallest hi-hats. Starting in the 1980s, a number of manufacturers also experimented with rivets in the lower cymbal. But by the end of the 1990s, the standard size was again , with a less-common alternative, and smaller hats mainly used for special sounds. Rivets in hi-hats failed to catch on.
Modern hi-hat cymbals are much heavier than modern crash cymbals, reflecting the trend to lighter and thinner crash cymbals as well as to heavier hi-hats. Another evolution is that a pair of hi-hat cymbals may not be identical, with the bottom often heavier than the top, and possibly vented. Some examples are Sabian's Fusion Hats with holes in the bottom cymbal, and the Sabian X-cellerator, Zildjian Master Sound and Zildjian Quick Beats, Paiste Sound Edge, and Meinl Soundwave. Some drummers even use completely mismatched hi-hats from different cymbal ranges (Zildjian's K/Z hats), of different manufacturers, and even of different sizes (similar to the K Custom Session Hats where the top hat is a smaller than the bottom). Max Roach was particularly known for using a top with a bottom.
Other recent developments include the X-hat (fixed, closed, or half-open hi-hats) and cable-controlled or remote hi-hats. Sabian introduced the Triple Hi-Hat, designed by Peter Kuppers. In this variation of the hi-hat, the top cymbal moves down and the bottom cymbal moves up simultaneously while the middle cymbal remains stationary.
Drop-clutches are also used to lock and release hi-hats while both feet are in use playing double bass drums. Drop clutches are commercially available from DW Drums, Gibraltar Hardware and Tama.
Modern stands.
The standard hi-hat features two cymbals mounted on a stand consisting of a mating metal tube and rod supported by a tripod and linked to a pedal. The stationary bottom cymbal sits atop the tube, typically perpendicular to the ground, but is but often fitted with an adjustment screw allowing it to be set slightly tilted. The top cymbal is mounted bell up on the rod and closed against the bottom by foot pressure on the pedal.
An integrated clutch assembly includes a spring which may be adjusted to set resistance, which also varies rate and tension of return, as well as an adjustment for the gap between cymbals when open.
Standard terminology has evolved. Open and closed hi-hat refer to notes struck while the two cymbals are apart or together (open or closed), while pedal hi-hat refers to parts or notes played solely with the pedal used to strike the two cymbals. Most cymbal patterns consist of both open and closed notes.
Some hi-hats allow the tripod to be tilted or rotated. Another configuration omits the tripod and attaches the stand to the side of the bass drum, particular suitable for kits with very large or double bass drums.
Clutch.
The standard clutch uses a knurled collar partially threaded below the cymbal and a pair of knurled rings above it. The collar is tightened against the end of the thread, while the rings are tightened against each other.
Drop clutch.
A drop clutch allows a pair of hats mounted on a conventional hi-hat stand to be closed without use of the pedal.
The drop clutch is provided with a lever that can be operated by hand or struck with a drumstick. This action releases the upper hi-hat cymbal, which falls onto the bottom cymbal and remains there, with gravity then holding the hats loosely closed, and allowing them to be played by the sticks in this position. Operation of the pedal re-engages the clutch and allows the player to resume normal playing.
Drop clutches were developed to allow players using double bass drum pedals to play closed hi-hats without needing to operate the hi-hat pedal, and this remains their primary application.
As it relies on gravity to close the cymbals, the drop clutch gives the player no control over the tension holding them together, and supplies only minimal tension. On the other hand, if the player manually lowers the top cymbal of a standard hi-hat stand before playing, this allows any desired tension to be set, and the pedal can still be used to increase the tension while playing, but not to open the hats or to reduce the tension. Some drummers prefer this technique and reject the drop clutch as too limiting to the sounds available.
In 2020, Tama introduced the Sizzle Touch Drop Clutch. This clutch when dropped, allows the distance between the top and bottom cymbals to be adjusted via an adjustment bolt on top of the clutch. To return the clutch to functioning as a standard one, the drummer simply depresses the hi-hat stand's pedal. The innovative design of the sizzle touch gives drummers more control over the sound of their hi-hats when dropped.
A less common alternative is the locking hi-hat pedal, such as the Tama "Cobra Clutch". This and similar high-end locking pedals do allow for control over the tension. It is engaged by pressing a lock pedal separate from the main pedal.
Cable hats.
A cable hat or remote hat uses a cable to allow hi-hat cymbals to be positioned independently of the pedal. Operation is otherwise normal.
X-hats.
An X-hat is an adapter to allow a pair of hi-hat cymbals to be mounted in a closed position on a cymbal stand. There is no pedal, the hats are simply kept closed at a constant tension, similar to a cymbal stack. They are associated with heavy metal music, particularly styles that use double bass drumming, a two-foot technique. By using an X-hat, a drummer who is already using both feet on the bass drum
pedals can still play hi-hat.
Non-cymbal hi-hats.
In addition to the many types of hi-hat cymbals on the market, there are also non-cymbal hi-hat pedals like the Latin Percussion Shekere hi-hat, the Remo Spoxe hi-hats created by Terry Bozzio in the late 80's, the Factory Metal Hat Crasherz or the Baldman Percussion Junk Hats. These kinds of percussion offer different textures in addition to the main hi-hat pedal on the drum kit and also options to expand the kit's pedal row.
Use.
When struck closed or played with the pedal, the hi-hat gives a short, crisp, muted percussive sound, referred to as a "chick". Adjusting the gap between the cymbals can alter the sound of the open hi-hat from a shimmering, sustained tone to something similar to a ride cymbal. When struck with a drumstick, the cymbals make either a short, snappy sound or a longer sustaining sandy sound depending on the position of the pedal.
It can also be played just by lifting and lowering the foot to clash the cymbals together, a style commonly used to accent beats 2 and 4 in jazz music. In rock music, the hi-hats are commonly struck every beat, or on beats 1 and 3, while the cymbals are held together. The drummer can control the sound by foot pressure. Less pressure allows the cymbals to rub together more freely, giving both greater sustain and greater volume for accent or crescendo. In shuffle time, a rhythm known as "cooking" is often employed. To produce this the cymbals are struck twice in rapid succession, being held closed on the first stroke and allowed to open just before the second, then allowed to ring before being closed with a chick to complete the pattern (the cymbals may or may not be struck on the chick).
A right-handed drummer will normally play the hi-hat pedal with his left foot, and may use one or both drumsticks. The traditional hi-hat rhythms of rock and jazz were produced by crossing the hands over, so the right stick would play the hi-hat while the left played the snare drum below it, but this is not universal. Some top modern drummers like Billy Cobham, Carter Beauford, Shawn Drover and Simon Phillips, play open handed, striking with their left. Some, such as Kenny Aronoff, and Jason Finn of The Presidents of the United States of America, use both techniques. Some drum kits may also include an extra hi-hat on the right for right-handed players. This is shown when drums or cymbals in the middle of the set are played with the hi-hat rhythm. The technique is common with metal genres, such as Lars Ulrich of Metallica and Mike Portnoy formerly of Dream Theater. In both rock and jazz, the drummer will often move the same stick pattern between the hi-hat cymbal and the ride cymbal, for example using the hi-hat in the verses and the ride in the chorus of a song, or using the ride to accompany a lead break or other instrumental solo.
Roger Taylor, drummer for the band Queen, plays with many unique hi-hat techniques, including opening of the hi-hat on every backbeat for a rhythm emphasis and leaving the hi-hat slightly open when hitting the snare. His trademark hi-hat beat is opening the hi-hat on first and third before hitting the snare.
Phil Rudd of AC/DC also uses distinct hi-hat techniques, which include very heavily accentuating the hi-hat hit on each beat and softer in between.
Charlie Watts of The Rolling Stones uses a technique in which he does not play the hi-hat in unison with the snare drum at all. If playing a standard 8th note pattern, he will play the hi-hat on 1 and 3 and not playing it on 2 and 4 where the snare drum is played.
In much hip-hop, the hi-hat is hit with drumsticks in a simple eighth-note pattern, although this playing is usually done by a drum machine or from an old recording from which the sound of a hi-hat is recorded and loaded into a sampler or similar recording-enabled equipment from which it is triggered.


Proceedings of the Institution of Mechanical Engineers, Part K

The Proceedings of the Institution of Mechanical Engineers, Part K: Journal of Multi-body Dynamics is a quarterly peer-reviewed scientific journal that covers mechanical design and dynamic analysis of multi-body systems. The journal was established in 1999 and is published by Sage Publications on behalf of the Institution of Mechanical Engineers.
Abstracting and indexing.
The journal is abstracted and indexed in Scopus and the Science Citation Index Expanded. According to the "Journal Citation Reports", its 2013 impact factor is 0.415.


Numbray

The numbray or spottail sleeper ray ("Narke dipterygia") is a species of electric ray in the family Narkidae. It may be found in shallow muddy estuaries or offshore depths. It is a weak swimmer that lies on the bottom, commonly buried. It eats small marine invertebrates and fish. It pounces on its prey and wraps its body around its prey, killing or stunning it with electrical shocks.
It has been observed that Numbrays are not as common as other types of rays in the area around the Indian Ocean. This can be attributed to the relatively large doubling time for a population, reaching up to 18 years.
References.
Momeninejad, Ali & Keivany, Yazdan & Sultan-Mohammadi, Vahid. (2014). First record of the numbray, Narke dipterygia (Bloch & Schneider, 1801) from Iran (Elasmobranchii: Narkidae). Iranian Journal of Ichthyology. 1. 298-301


List of Rodenstock Retina DKL-mount lenses


Nagant wz. 30

Rewolwer Nagant wz. 30 and wz. 32 were two Polish derivatives of the Nagant M1895 revolver. They were almost identical to the Soviet variants with only minor differences in weight, length and sights design.
The Nagant M1895 was mass-produced in Imperial Russia and the Soviet Union as a standard side-arm of officers and NCOs. After Poland regained independence in 1918, the Polish Army inherited some captured revolvers and pressed them into Polish service as the rewolwer wz. 1895 Nagant - Mark 1895 revolver. After the Polish-Bolshevik War the army decided to focus on the 7.92 mm calibre and the Nagant revolvers were withdrawn from active service.
The Nagant revolver remained in service with the State Police, along with a large variety of sidearms of all types and calibres. The Police used also Modèle 1892 revolver and Rast & Gasser M1898 revolvers as well as a number of pistol designs: Mauser M1910, Mauser C96, Beretta M1923, various Browning pistols (wz. 1900, wz. 1910 and wz. 1922), Ortgies Semi-Automatic Pistol, Cebra wz. 1916, Frommer wz. 1910, Steyr M1912, Roth–Steyr M1907 and Parabellum P08.
In September 1927 the Police Headquarters started a poll among police officers to determine which firearm should be used as a standard sidearm throughout the police force, and the Nagant system was chosen for its durability and simplicity. As the number of Russian ex-military weapons was limited, in 1930 the state-owned "Fabryka Broni" works in Radom developed a slightly modified variant, designated "Nagant wz. 30". Comparing to the Russian or Belgian models, the new Polish model was slightly lighter, and the barrel was slightly shorter. In 1932 the design was further modified by the relocation of the sight (and giving a new "Rewolwer wz. 32" designation). Between 1929 and 1935 the Radom works produced 7,166 revolvers of both variants.
Both the original M1895 Nagant and its later clones remained the standard police weapon used by the State Police and Postal Guards throughout the 1930s, though with time they were often replaced with more modern designs like the Beretta M1934 and Walther PPK. They were also widely used by mobilised policemen during the German and Soviet invasion of Poland of 1939.


Soken tester

Soken tester - is a portable single yoke instrument for assessing the power loss in electrical steel laminations.
It has been developed for quick assessment of power loss in electrical steel sheet without the need for cutting and annealing, as it is the case for standardised methods like Epstein frame.
The power loss can be estimated at 1.0 T, 1.5 T and 1.7 T and two frequencies 50 Hz and 60 Hz. Lamination thickness can be set within a range from 0.01 mm to 0.99 mm and there is no option for selecting the material density.
The power loss is measured as a product of magnetic field and flux density. Both these signals are detected from the magnetising yoke, which is contained in an aluminium head (55 mm in diameter as shown in the photo). The flux density is measured from a secondary winding wound on the yoke. For that reason there is a great influence on the measured values, hence great care should be taken that the measuring head is placed on a clean and even sample. The measurement is based on similar principle as employed in the standardised single sheet tester.
The manufacturers of the instrument claim that its measurement uncertainty is lower than 5% (as referred to results from Epstein frame).
The Soken tester has been developed in the second half of 20th century initially as a relatively cheap and easy to use analogue device, but recently also digital devices are available.