The Labrador Sea is an arm of the North Atlantic Ocean between the Labrador Peninsula and Greenland. The sea is flanked by continental shelves to the southwest and northeast, it connects to the north with Baffin Bay through the Davis Strait. It has been described as a marginal sea of the Atlantic; the sea formed upon separation of the North American Plate and Greenland Plate that started about 60 million years ago and stopped about 40 million years ago. It contains one of the world's largest turbidity current channel systems, the Northwest Atlantic Mid-Ocean Channel, that runs for thousands of kilometers along the sea bottom toward the Atlantic Ocean; the Labrador Sea is a major source of the North Atlantic Deep Water, a cold water mass that flows at great depth along the western edge of the North Atlantic, spreading out to form the largest identifiable water mass in the World Ocean. The Labrador Sea formed upon separation of the North American Plate and Greenland Plate that started about 60 million years ago and stopped about 40 million years ago.
A sedimentary basin, now buried under the continental shelves, formed during the Cretaceous. Onset of magmatic sea-floor spreading was accompanied by volcanic eruptions of picrites and basalts in the Paleocene at the Davis Strait and Baffin Bay. Between about 500 BC and 1300 AD, the southern coast of the sea contained Dorset and Inuit settlements; the International Hydrographic Organization defines the limits of the Labrador Sea as follows: On the North: the South limit of Davis Strait. On the East: a line from Cape St. Francis 47°45′N 52°27′W to Cape Farewell. On the West: the East Coast of Labrador and Newfoundland and the Northeast limit of the Gulf of St. Lawrence – a line running from Cape Bauld to the East extreme of Belle Isle and on to the Northeast Ledge. Thence a line joining this ledge with the East extreme of Cape St. Charles in Labrador; the Labrador Sea is 1,000 km wide where it joins the Atlantic Ocean. It becomes shallower, to less than 700 m towards Baffin Bay and passes into the 300 km wide Davis Strait.
A 100–200 m deep turbidity current channel system, about 2–5 km wide and 3,800 km long, runs on the bottom of the sea, near its center from the Hudson Strait into the Atlantic. It is called the Northwest Atlantic Mid-Ocean Channel and is one of the world's longest drainage systems of Pleistocene age, it appears as a submarine river bed with numerous tributaries and is maintained by high-density turbidity currents flowing within the levees. The water temperature varies between − 1 °C in 5 -- 6 °C in summer; the salinity is low, at 31–34.9 parts per thousand. Two-thirds of the sea is covered in ice in winter. Tides are semi-diurnal. There is an anticlockwise water circulation in the sea, it is initiated by the East Greenland Current and continued by the West Greenland Current, which brings warmer, more saline waters northwards, along the Greenland coasts up to the Baffin Bay. The Baffin Island Current and Labrador Current transport cold and less saline water southward along the Canadian coast; these currents carry numerous icebergs and therefore hinder navigation and exploration of the gas fields beneath the sea bed.
The speed of the Labrador current is 0.3–0.5 m/s, but can reach 1 m/s in some areas, whereas the Baffin Current is somewhat slower at about 0.2 m/s. The Labrador Current maintains the water temperature at 0 °C and salinity between 30 and 34 parts per thousand; the sea provides a significant part of the North Atlantic Deep Water – a cold water mass that flows at great depth along the western edge of the North Atlantic, spreading out to form the largest identifiable water mass in the World Ocean. The NADW consists of three parts of different origin and salinity, the top one, the Labrador Sea Water, is formed in the Labrador Sea; this part occurs at a medium depth and has a low salinity, low temperature and high oxygen content compared to the layers above and below it. LSW has a low vorticity, i.e. the tendency to form vortices, than any other water in North Atlantic that reflects its high homogeneity. It has a potential density of 27.76–27.78 mg/cm3 to the surface layers, meaning it is denser, thus sinks under the surface and remains homogeneous and unaffected by the surface fluctuations.
The northern and western parts of the Labrador Sea are covered in ice between June. The drift ice serves as a breeding ground for seals in early spring; the sea is a feeding ground for Atlantic salmon and several marine mammal species. Shrimp fisheries intensified toward 2000, as well as cod fishing. However, the cod fishing depleted the fish population in the 1990s near the Labrador and West Greenland banks and was therefore halted in 1992. Other fishery targets include haddock, Atlantic herring and several species of flatfish and pelagic fish such as sand lance and capelin, they are most abundant in the southern parts of the sea. Beluga whales, while abundant to the north, in the Baffin Bay, where their population reaches 20,000, are rare in the Labrador Sea s
Eric Cheney was an English motorcycle racer and independent constructor. He was known as one of the best motorcycle frame designers of his era, concentrating in the off-road competition aftermarket. Cheney attended a school in Winchester based on Lancasterian principles before joining the Royal Navy at the age of 18, where he served on wartime Arctic convoys and in motor torpedo boats and gained experience of engineering and working on high performance engines. Cheney worked on the development of remote controlled submarines for the Royal Navy. After World War II, Cheney joined the motorcycle dealers Archers of Aldershot as a mechanic. Cheney began racing motocross and became one Britain's best riders, along with his travelling companion Les Archer, who went on to become European champion, he had ten successful years on the Continental circuit but a prolonged illness due to an infection contracted while racing in Algeria ended his riding career. He moved into bike preparation and designs for motorcycle suspension systems.
Cheney had no formal training as a motorcycle designer yet was able to create original and high-performance motorcycle chassis designs working in a simple workshop, a domestic garage. His approach has been described as "like a medieval engineer" as in an age of computer-aided design and significant resources for research and development teams, he worked by intuition. Eric relied on his long personal experience of international off-road competition riding and would prepare his initial designs for a new motorcycle frame in chalk on the wall of his workshop. Experimenting with different lines until he was satisfied, Cheney would form the steel tubing using his chalk drawings as a guide. Only when he had built a working prototype motorcycle would he start work on a final jig for mass production, he was once quoted as saying "I know when it's right and it screams at me when it's wrong."In the late 1960s, the British motorcycle industry was unable to support a national team to compete in the International Six Days Trial so, Cheney hand built a limited number of ISDT Cheney-Triumphs using his own design of twin down-tube frame with a specially tuned Triumph 5TA engine.
Fitted with tapered conical hubs, special motocross forks and large alloy fuel tanks, a Cheney Triumph was first used in the 1968 British Trophy Team. In 1970 and 1971 three 504cc Cheney Triumphs were used by the British team in the ISDT, in which Cheney won a manufacturer's prize. Replicas were built. Cheney's most noted successes were in the Grand Prix road racing championships, with Phil Read using his chassis in tandem with a Yamaha engine to win the 1971 250cc world championship, his designs were the last British ones to win a Grand Prix. He never worked for any of the major manufacturers but maintained a productive relationship with BSA in its heyday. After the demise of BSA in 1972, Cheney joined with former BSA factory rider John Banks to develop and campaign a successful BSA powered motocross bike; some of Cheney's motorcycle designs are now famous in their own right, such as the competition BSA Gold Stars of Jerry Scott and Keith Hickman and the John Banks replica which used a BSA B50 engine specially tuned by Cheney.
He built some racing frames for Suzuki Grand Prix motorcycles in 1968 and, it has been suggested that Suzuki engineers incorporated features of Cheney's designs, such as magnesium hubs and lower fork legs into production road going motorcycles. Cheney's company was known as Eric Cheney Designs changed to Inter-Moto, now known as Cheney Racing. American actor Steve McQueen, an experienced off-road rider who represented the United States in the ISDT bought a number of Cheney's motorcycles at full price because he considered them better than other makes. Cheney Racing web site
Trimethylenemethane is a chemical compound with formula C4H6. It is a neutral free molecule with two unsatisfied valence bonds, is therefore a reactive free radical. Formally, it can be viewed as an isobutylene molecule C4H8 with two hydrogen atoms removed from the terminal methyl groups; the electronic structure of trimethylenemethane was discussed in 1948. It is a neutral four-carbon molecule containing four pi molecular orbitals; when trapped in a solid matrix at about 90 K, the six hydrogen atoms of the molecule are equivalent. Thus, it can be described either as zwitterion, or as the simplest conjugated hydrocarbon that cannot be given a Kekulé structure, it can be described as the superposition of three states: It has a triplet ground state, is therefore a diradical in the stricter sense of the term. Calculations predict a planar molecule with three-fold rotational symmetry, with approximate bond lengths 1.40 Å and 1.08 Å. The H–C–H angle in each methylene is about 121 degrees. Of the three singlet excited states, the first one, 11A1, is a closed shell diradical with flat geometry and degenerate threefold symmetry.
The second one, 11B2, is an open-shell radical with a D3h-symmetric equilibrium between three equal geometries. The third singlet state, 21A1/1A1', is a D3h-symmetric equilibrium of three geometries; the next higher energy states are degenerate 13A1 and 23B2, with one excited electron. Trimethylenemethane was first obtained from photolysis of the diazo compound 4-methylene-Δ1-pyrazoline with expulsion of nitrogen, in a frozen dilute glassy solution at −196 C, it was obtained from photolysis of 3-methylenecyclobutanone, both in cold solution and in the form of a single crystal, with expulsion of carbon monoxide. In both cases, trimethylenemethane was detected by electron spin resonance spectroscopy. Trimethylenemethane has been obtained by treating potassium with 2-iodomethyl-3-iodopropene|isobutylene diiodide 2C=CH2 in the gas phase; however the product dimerizes to yield 1,4-dimethylenecyclohexane, 2-methylpropene by abstracting two hydrogen atoms from other molecules. A number of organometallic complexes have been prepared, starting with Fe3, obtained by the ring-opening of methylenecyclopropane with diiron nonacarbonyl.
The same complex was prepared by the salt metathesis reaction of disodium tetracarbonylferrate with 1,1-bisethylene. Related reactions give M4; the reaction leading to Mo4 gives Mo3 containing a dimerized TMM ligand. TMM complexes have been examine for their potential in organic synthesis in the trimethylenemethane cycloaddition reaction with only modest success. One example is a palladium-catalyzed cycloaddition of trimethylenemethane