Gerard Corben was the lead guitarist in the Australian rock band, The Lime Spiders. After the band split in 1990, Gerard spent a few years simply playing guitar at home or with friends, occasionally playing gigs. In 2002, Gerard joined a folk band called Wheelers and Dealers where he plays guitar.
At the moment he teaches guitar lessons . He recently played with The Lime Spiders at a hotel .
A V4 engine is a V form engine with four cylinders.
Lancia produced several narrow-angle V4 engines from the 1920s through 1960s for cars like the Lambda, Augusta, Artena, Aprilia, Ardea, Appia, and Fulvia. These were a spiritual predecessor for Volkswagen’s VR6 family.
The Ford of Europe produced two totally different V4 engines with a balance shaft, one in the UK and one in Germany:
Saab featured a 1.5L OHV V4 engine in their 95, 96 and Sonett models, producing and of torque.
The Ukrainian manufacturer ZAZ also used air cooled V4s with a balance shaft, produced by MeMZ and used in Zaporozhets cars.
V4 engines are also sometimes found in motorcycles, for instance the
One other large use of the V4 engine is in outboard motors. They are two stroke cycle and generally carbureted. Some manufacturers are Johnson, Evinrude and Yamaha. This type of engines is popular because of their small size, while still allowing 140+ horsepower.
A common mistake is to refer to the much more common inline 4 as a V4.
Stéphane Peterhansel (b 6 August, 1965) is a rally racing driver from France. He won the Paris Dakar Rally riding Yamaha motorcycles in 1991, 1992, 1993, 1995, 1997, and 1998 and then again driving Mitsubishi Pajero SUVs in 2004, 2005 and 2007, making him one of the most successful drivers in the history of that race. He competed in the Race of Champions in 2005 and 2006 and is also a two-time World Enduro Champion.
1991: 1º in Paris Dakar Rally (motorcycle)
1992: 1º in Paris Dakar Rally (motorcycle)
1993: 1º in Paris Dakar Rally (motorcycle)
1995: 1º in Paris Dakar Rally (motorcycle)
1996: 1º in UAE Desert Challenge (motorcycle)
1997: 1º in Paris Dakar Rally (motorcycle)
4º in UAE Desert Challenge (motorcycle)
1998: 1º in Paris Dakar Rally (motorcycle);
1º in 24 Hours of Chamonix
1999: 7º in Paris Dakar Rally, with a Nissan car
2000: 2º in Paris Dakar Rally, with a Mega car
2001: 1º T1, Paris Dakar Rally, with a Nissan
2002: 1º in Tunisia Rally;
1º in UAE Desert Challenge
2003: 3º in Paris Dakar Rally(cars)
2º in Italia Baja;
1º in UAE Desert Challenge
2004: 1º in Paris Dakar Rally;
1º in Tunisia Rally;
1º Morocco Rally;
8º in UAE Desert Challenge
2005: 1º in Paris Dakar Rally
5 in dakar 2006
2007: 1º in Lisbon Dakar Rally
A silver-oxide battery (IEC code: S), also known as a silver-zinc battery, is a primary cell (although it may be used as a secondary cell with an open circuit potential of 1.86 volts). Silver-oxide batteries have a long life and very high energy/weight ratio, but a prohibitive cost for most applications due to the high price of silver. They are available in either very small sizes as button cells where the amount of silver used is small and not a significant contributor to the overall product costs, or in large custom design batteries where the superior performance characteristics of the silver-oxide chemistry outweigh cost considerations. The large cells found some applications with the military. For example in Mark 37 torpedoes or on Alfa class submarines.
A silver oxide battery is a small-sized primary battery using zinc as the negative electrode (anode), silver oxide as the positive electrode (cathode) plus an alkaline electrolyte, usually sodium hydroxide (NaOH) or potassium hydroxide (KOH). The chemical reaction that takes place inside the battery is the following:
Zinc is the activator in the negative electrode and corrodes in alkaline solution. When this happens, it becomes difficult to maintain the capacity of the unused battery. The zinc corrosion causes electrolysis in the electrolyte, resulting in the production of hydrogen gas, a rise of inner pressure and expansion of the cell. Mercury has been used in the past to suppress the corrosion, despite its harmful effects on the environment.
Compared to other batteries, a silver-oxide battery has a higher open circuit potential than a mercury battery, and a flatter discharge curve than a standard alkaline battery.
The Small Tight Aspect Ratio Tokamak, or START was a nuclear fusion experiment that used magnetic confinement to hold plasma. The experiment began at the Culham Science Centre in the United Kingdom in 1991 and was retired in 1998. It was built as a low cost design, largely using parts already available to the START team. The START experiment developed the tokamak by changing the previous toroidal shape into a tighter, almost spherical, doughnut shape. The new shape increased efficiency by reducing the cost over the conventional design, whilst the field required to maintain a stable plasma was a factor of 10 less.
The START team holds the current highest record plasma pressure, which they achieved by using a neutral beam injector to heat the plasma. In March 1998, the START experiment finished and has since been disassembled and transferred to the ENEA research laboratory at Frascati, Italy. The START team began the Mega Ampere Spherical Tokamak Experiment or MAST in 1999 which still operates in the Culham Science Centre, UK.
Motorcycle (artist) can refer to:
Lever-action is a type of firearm action which uses a lever located around the trigger guard area (often including the trigger guard itself) to load fresh cartridges into the chamber of the barrel when the lever is worked. One of the most famous lever-action firearm is undoubtedly the Winchester rifle, but many manufacturers- notably Marlin and Savage- also produce lever-action rifles. While the term lever-action generally implies a repeating firearm, it is also sometimes applied to a variety of single-shot or falling-block actions that use a lever for cycling, such as the Martini-Henry or the Ruger No. 1.
Contents |
The first significant lever-action design was the Spencer repeating rifle, a magazine-fed lever-operated breech-loading rifle designed by Christopher Spencer in 1860. It was fed from a removable seven-round tube magazine, enabling the rounds to be fired one after another, and which, when emptied, could be exchanged for another. Over 20,000 were made, and it was adopted by the United States and used during the American Civil War, marking the first adoption of a removable-magazine-fed infantry-and-cavalry rifle by any country.
Unlike later designs, the early Spencer’s lever only served to unlock the falling-block action and load a new cartridge from the magazine; it did not cock the hammer, and thus the hammer had to be cocked after the lever was operated to prepare the rifle to fire. The Henry rifle, produced by Oliver Winchester in 1860, used a centrally-located hammer rather than the offset hammer typical of muzzleloading rifles, and this hammer was cocked by the rearward movement of the Henry’s bolt. The Henry also placed the magazine under the barrel, rather than in the buttstock, a trend followed by most tubular magazines since.
Lever action rifles were used extensively by irregular forces during the Spanish Civil War in the 1930s. Typically, these were Winchester or Winchester copies of Spanish manufacture.
John Marlin, founder of Marlin Firearms Company, New Haven, Connecticut, introduced Marlin’s first lever-action repeating rifle as the Model 1881. Its successor was the Marlin Model 1894, which is still in production today.
By the 1890s, lever-actions had evolved into a form that would last for over a century. Both Marlin and Winchester released new model lever-action rifles in 1894. The Marlin rifle is still in production, whereas production of the Winchester 94 ceased in 2006. While externally similar, the Marlin and Winchester rifles are quite different internally; the Marlin has a single-stage lever action, while the Winchester has a double-stage lever. The double-stage action is easily seen when the Winchester’s lever is operated, as first the entire trigger group drops down, unlocking the bolt, and then the bolt is moved rearward to eject the fired cartridge.
The fledgling Savage Arms Company became well-known after the development of its popular hammerless Savage Model 99 lever action sporting rifle, also of .30 caliber. The former two models, and various copies of them, make up the bulk of the lever-action rifles made by the company, while the somewhat odd .303 Savage cartridge (not interchangeable with the military .303 British cartridge in any way) gradually eroded the Model 99’s popularity and production was eventually abandoned.
More recently, Sturm Ruger and Company introduced a number of new lever-action designs in the 1990s, unusual because most lever action designs date from before World War II, in the period before reliable semi-automatic rifles became widely available.
Early attempts at repeating shotguns invariably centered around either bolt-action or lever-action designs, drawing obvious inspiration from the repeating rifles of the time.
The earliest successful repeating shotgun was the lever-action Winchester M1887, designed by John Browning in 1885 at the behest of the Winchester Repeating Arms Company, who wanted to market a repeating shotgun. The lever-action design was chosen for reasons of brand recognition, Winchester being best known for manufacturing lever-action firearms at the time, despite the protestations of Browning, who pointed out that a pump-action design would be much better for a shotgun. Initially chambered for black powder shotgun shells (as was standard at the time), the Winchester Model 1901 was a later model chambered for 10ga smokeless powder shotgun shells. Their popularity waned after the introduction of pump-action shotguns such as the Winchester Model 1897, and production was discontinued in 1920. Modern reproductions are (or have been), however, manufactured by Norinco in China and ADI Ltd. in Australia, while Winchester continued to manufacture the .410 gauge Model 9410, effectively a Winchester Model 94 chambered for .410 gauge shotgun shells, until 2006.
While lever-action rifles were (and are) popular with hunters and sporting shooters, they were not widely accepted by the military. One significant reason for this was that it is harder to fire a lever-action from the prone position (compared to a straight-pull or bolt-action rifle), and while nominally possessing a greater rate of fire (Contemporary Winchester advertisements claimed their rifles could fire 2 shots a second) than bolt-action rifles, lever-action firearms are also generally fed from a tubular magazine, which limits the ammunition that can be used in them. Pointed centerfire Spitzer bullets, for example, can cause explosions in a tubular magazine, as the point of each cartridge’s projectile rests on the primer of the next cartridge in the magazine. The tubular magazine may also negatively impact the harmonics of the barrel, which limits the theoretical accuracy of the rifle; a tubular magazine under the barrel pushes the center of gravity forward, it may alter the balance of the rifle in ways undesirable to some shooters. It should be noted however, that many of the newer lever action rifles by Marlin are capable of shooting groups smaller than 1 minute of angle, comparable to most modern bolt-action rifles.
Due to the higher rate of fire and shorter overall length than most bolt-action rifles, lever-actions have remained popular to this day for sporting use, especially short- and medium-range hunting in forests, scrub, or bushland. Lever-action firearms are also used in some quantity by prison guards in the United States, as well as by wildlife authorities/game wardens in many parts of the world.
Most lever-action designs are not as strong as bolt-action or semi-automatic designs, and as a result lever-action rifles tend to be generally found in low- and medium-pressure cartridges such as .30-30 Winchester or .44 Magnum, although the Marlin Model 1894 is available in three high-pressure magnum calibers. The most common caliber is by far the .30-30, which was introduced by Winchester with the Model, 1894. Other common calibers for Lever-action firearms include .38 Special/.357 Magnum, .44 Special/.44 Magnum, .41 Magnum, .45-70, .32-20 Winchester, and .22 caliber rimfire. It should be noted that lever-action designs using stronger, rotary locking bolts (such as the Browning BLR) are usually fed from box magazines and are not limited to round nose bullet designs, as well as being able to handle a greater range of calibers than a traditional lever-action design.
Lever-action shotguns such as the Winchester Model 1887 were chambered in 10 or 12-gauge black powder shotgun shells, whereas the Model 1901 was chambered for 10 gauge smokeless shotshells. Modern reproductions are chambered for 12 gauge smokeless shells, while the Winchester Model 9410 shotgun is available in .410 bore.
In mathematics, specifically in category theory, an exponential object or power object is the categorical equivalent of a function space in set theory. Categories with all finite products and exponential objects are called cartesian closed categories.
Contents |
Let C be a category with binary products and let Y and Z be objects of C. The exponential object ZY can be defined as a universal morphism from the functor –×Y to Z. (The functor –×Y from C to C maps objects X to X×Y and morphisms φ to φ×idY).
Explicitly, the definition is as follows. An object ZY, together with a morphism
is an exponential object if for any object X and morphism g : (X×Y) → Z there is a unique morphism
such that the following diagram commutes:
If the exponential object ZY exists for all objects Z in C, then the functor which sends Z to ZY is a right adjoint to the functor –×Y. In this case we have a natural bijection between the hom-sets
In the category of sets, the exponential object <math>Z^Y</math> is the set of all functions from <math>Y</math> to <math>Z</math>. The map <math>\mathrm{eval}\colon (Z^Y \times Y) \to Z</math> is just the evaluation map which sends the pair (f, y) to f(y). For any map <math>g\colon (X \times Y) \rightarrow Z</math> the map <math>\lambda g\colon X\to Z^Y</math> is the curried form of <math>g</math>:
In the category of topological spaces, the exponential object ZY exists provided that Y is a locally compact Hausdorff space. In that case, the space ZY is the set of all continuous functions from Y to Z together with the compact-open topology. The evaluation map is the same as in the category of sets. If Y is not locally compact Hausdorff, the exponential object may not exist (the space ZY exists, but fails to be an exponential object because the adjunction with the product only holds when Y is locally compact Hausdorff). For this reason the category of topological spaces fails to be cartesian closed.
Franklin Electric is a leading manufacturer of submersible pumps, fueling systems and other applications such as submersible electric motors & center pivot irrigation systems.
Until 2004, Franklin Electric was primarily a supplier to OEMs such as ITT/Goulds and Pentair. With the acquisition of Little Giant Pump, JBD (formerly the pump line of Jacuzzi), and Pioneer Pump; the company has changed its focus to pump manufacturing. ITT/Goulds and Pentair in turn have formed a joint venture called Faradyne Motors to manufacture their own motors.
Franklin Electric has manufacturing facilities in the United States, Germany, Czech Republic, Italy, Mexico, Australia, South Africa, China, and Japan.
In predicate logic, universal quantification is an attempt to formalize the notion that something (a logical predicate) is true for everything, or every relevant thing.
The resulting statement is a universally quantified statement, and we have universally quantified over the predicate.
In symbolic logic, the universal quantifier (typically <math> \forall </math> ) is the symbol used to denote universal quantification, and is often informally read as “given any” or “for all”.
Quantification in general is covered in the article on quantification, while this article discusses universal quantification specifically.
Compare this with existential quantification, which says that something is true for at least one thing.
Contents |
Suppose you wish to say
This would seem to be a logical conjunction because of the repeated use of “and.”
But the “etc” can’t be interpreted as a conjunction in formal logic.
Instead, rephrase the statement as
This is a single statement using universal quantification.
Notice that this statement is really more precise than the original one.
It may seem obvious that the phrase “etc” is meant to include all natural numbers, and nothing more, but this wasn’t explicitly stated, which is essentially the reason that the phrase couldn’t be interpreted formally.
In the universal quantification, on the other hand, the natural numbers are mentioned explicitly.
This particular example is true, because you could put any natural number in for n and the statement “2·n = n + n” would be true.
In contrast, “For all natural numbers n, 2·n > 2 + n” is false, because if you replace n with, say, 1 you get the false statement “2·1 > 2 + 1″.
It doesn’t matter that “2·n > 2 + n” is true for most natural numbers n: even the existence of a single counterexample is enough to prove the universal quantification false.
On the other hand, “For all composite numbers n, 2·n > 2 + n” is true, because none of the counterexamples are composite numbers.
This indicates the importance of the domain of discourse, which specifies which values n is allowed to take.
Further information on using domains of discourse with quantified statements can be found in the Quantification article.
But in particular, note that if you wish to restrict the domain of discourse to consist only of those objects that satisfy a certain predicate, then for universal quantification, you do this with a logical conditional.
For example, “For all composite numbers n, 2·n > 2 + n” is logically equivalent to “For all natural numbers n, if n is composite, then 2·n > 2 + n“.
Here the “if … then” construction indicates the logical conditional.
In symbolic logic, we use the universal quantifier symbol <math> \forall </math> (an upside-down letter “A” in a sans-serif font) to indicate universal quantification.
Thus if P(n) is the predicate “2·n > 2 + n” and N is the set of natural numbers, then
is the (false) statement
Similarly, if Q(n) is the predicate “n is composite”, then
is the (true) statement
Several variations in the notation for quantification (which apply to all forms) can be found in the quantification article.
But there is a special notation used only for universal quantification, which we also give here:
The parentheses indicate universal quantification by default.
Note that a quantified propositional function is a statement; thus, like statements, quantified functions can be negated. The notation mathematicians and logicians utilize to denote negation is: <math>\lnot\ </math>.
For example, let P(x) be the propositional function “x is married”; then, for a Universe of Discourse X of all living human beings, consider the universal quantification “Given any living person x, that person is married”:
A few second’s thought demonstrates this as irrevocably false; then, truthfully, we may say, “It is not the case that, given any living person x, that person is married”, or, symbolically:
Take a moment and consider what, exactly, negating the universal quantifier means: if the statement is not true for every element of the Universe of Discourse, then there must be at least one element for which the statement is false. That is, the negation of <math>\forall{x}{\in}\mathbf{X}\, P(x)</math> is logically equivalent to “There exists a living person x such that he is not married”, or:
Generally, then, the negation of a propositional function’s universal quantification is an existential quantification of that propositional function’s negation; symbolically,
A common error is writing “all persons are not married” (i.e. “there exists no person who is married”) when one means “not all persons are married” (i.e. “there exists a person who is not married”):
A rule of inference is a rule justifying a logical step from hypothesis to conclusion. There are several rules of inference which utilize the universal quantifier.
Universal instantiation concludes that, if the propositional function is known to be universally true, then it must be true for any arbitrary element of the Universe of Discourse. Symbolically, this is represented as
where c is a completely arbitrary element of the Universe of Discourse.
Universal generalization concludes the propositional function must be universally true if it is true for any arbitrary element of the Universe of Discourse. Symbolically, for an arbitrary c,
It is especially important to note c must be completely arbitrary; else, the logic does not follow: if c is not arbitrary, and is instead a specific element of the Universe of Discourse, then P(c) only implies an existential quantification of the propositional function.