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The Caterpillar 797 is an off-highway, ultra class, two axle, mechanical powertrain haul truck developed and manufactured in the United States by Caterpillar Inc. specifically for high production mining and heavy-duty construction applications world-wide. The 797 is Caterpillar’s largest, highest capacity haul truck. The latest version, the 797F, offers one of the largest haul truck payload capacities in the world, up to 400 short tons (363 t). The Caterpillar 797 series trucks employ mechanical drive powertrains in contrast to the diesel-electric powertrains of similar haul trucks offered by competitors. During initial development in 1997, a diesel-electric powertrain was considered for the 797, but this powertrain configuration was not developed because Caterpillar considered a mechanical drive powertrain more appropriate for market conditions at that time. A gross 4,000 hp (2,983 kW) Cat C175-20 ACERT single block, 20-cylinder, electronic common rail injection, quad turbocharged, air-to-air aftercooled, four-stroke diesel engine powers the 797F. The 797 series haul trucks are equipped with a rear axle mounted, computer controlled, seven speed planetary transmission with an integral lock-up torque converter. The Caterpillar 797 series haul trucks run on the largest tire in the world, the 13.2 ft tall, 11,680 lb Michelin 59/80R63 XDR. This radial tire was developed by Michelin in conjunction with Caterpillar specifically for the 797. Six tires are required per truck at a cost of approximately $42,500 per tire. Large components are manufactured at various Caterpillar and supplier facilities, then shipped to the customer site for final assembly by Caterpillar field engineers. The 3524B engine is made in Lafayette, Indiana and the largest frame component is cast in Amite City, Louisiana. These components are shipped to the Decatur, Illinois assembly plant where they are joined with the rear differential. These items alone require six to seven semi-trailer truck loads. The cab is made in Joliet, Illinois. The dump body requires four semi-trailer truck loads, while the six tires require two semi-trailer truck loads. In total, one 797 requires 12 to 13 semi-trailer truck loads that originate at various manufacturing facilities and deliver to the customer site. If a 797 must be moved from one job site to another for any reason, it can not be driven on public roads due to its exceptional size and weight. Moving a 797 requires dis-assembly, loading onto semi-trailer trucks, transport and re-assembly at the new location. [READ THE REST OF THIS ARTICLE]



LED-backlit LCD television (called LED TV by Samsung Electronics, Panasonic,Toshiba, Philips, LG Electronics, ProScan and Vizio and not to be confused with true LED displays) is an LCD TV that uses LED backlighting rather than fluorescent lights used in traditional LCD televisions. The LEDs can come in two forms, Dynamic RGB LEDs which are positioned behind the panel, or white Edge-LEDs positioned around the rim of the screen which use a special diffusion panel to spread the light evenly behind the screen. RGB Dynamic LEDs allow dimming to occur locally creating specific areas of darkness on the screen. This can show truer blacks, whites and PRs at much higher dynamic contrast ratios, at the cost of less detail in small bright objects on a dark background, such as star fields. Edge-LEDs allow for LED-backlit TVs to become extremely thin. The light is diffused across the screen by a special panel which produces a uniform color range across the screen. Sharp also has LED backlighting technology that aligns the LEDs on back of the TV like the RGB Dynamic LED backlight, but it lacks the local dimming of other sets. LED-backlit LCD TVs are considered a more sustainable choice, with a longer life and better energy efficiency than plasmas and conventional LCD TVs. Unlike CCFL backlights, LEDs also use no mercury in their manufacture. However, other elements such as gallium and arsenic are used in the manufacture of the LED emitters themselves, meaning there is some debate over whether they are a significantly better long term solution to the problem of TV disposal. Because LEDs are able to be switched on and off more quickly than CCFL displays and can offer a higher light output, it is theoretically possible to offer very high contrast ratios. They can produce deep blacks (LEDs off) and a high brightness (LEDs on), however care should be taken with measurements made from pure black and pure white outputs, as technologies like Edge-LED lighting do not allow these outputs to be reproduced simultaneously on-screen. [READ THE REST OF THIS ARTICLE]



A car battery is a type of rechargeable battery that supplies electric energy to an automobile. This also may describe a traction battery used for the main power source of an electric vehicle. Automotive starter batteries provide a nominal 12-volt potential difference by connecting six galvanic cells in series. Each cell provides 2.1 volts for a total of 12.6 volt at full charge. Lead-acid batteries are made up of plates of lead and separate plates of lead dioxide, which are submerged into an electrolyte solution of about 35% sulfuric acid and 65% water. This causes a chemical reaction that releases electrons, allowing them to flow through conductors to produce electricity. As the battery discharges, the acid of the electrolyte reacts with the materials of the plates, changing their surface to lead sulphate. When the battery is recharged, the chemical reaction is reversed: the lead sulfate reforms into lead oxide and lead. With the plates restored to their original condition, the process may now be repeated. In normal automotive service the vehicle's charge system, also referred to as charging system, consisting of the engine-driven alternator and the voltage regulator powers the vehicle's electrical systems and restores charge used from the battery during engine cranking. When installing a new battery or recharging a battery that has been accidentally discharged completely, one of several different methods can be used to charge it. The most gentle of these is called trickle charging. Other methods include slow-charging and quick-charging, the latter being the harshest. In the United States, about 97% of lead from used batteries is reclaimed for recycling.[6] Many cities offer battery recycling services for lead-acid batteries. In several U.S. states and Canadian provinces, purchasers of new lead-acid batteries are charged a small deposit fee, refunded when the replaced battery is returned. Car batteries should always be handled with proper protective equipment (goggles, overalls, gloves), and make certain there are no sparks or smoking close by. [READ THE REST OF THIS ARTICLE]



Skunks are mammals best known for their ability to secrete a liquid with a strong, foul-smelling odor. General appearance ranges from species to species, from black-and-white to brown or cream colored. There are 10 species of skunks, which are divided into four genera: Mephitis (hooded and striped skunks, two species), Spilogale (spotted skunks, two species), Mydaus (stink badgers, two species), and Conepatus (hog-nosed skunks, four species). The two skunk species in the Mydaus genus inhabit Indonesia and the Philippines; all other skunks inhabit the Americas from Canada to central South America. Skunk species vary in size from about 15.6 to 37 inches (40 to 94 cm) and in weight from about 1.1 pounds (0.50 kg) (the spotted skunks) to 18 pounds (8.2 kg) (the hog-nosed skunks). They have a moderately elongated body with relatively short, well-muscled legs, and long front claws for digging. Skunks are omnivorous, eating both plant and animal material and changing their diet as the seasons change. They eat insects and larvae, earthworms, small rodents, lizards, salamanders, frogs, snakes, birds, moles, and eggs. They also commonly eat berries, roots, leaves, grasses, fungi, and nuts. The most notorious feature of skunks is their anal scent glands, which they can use as a defensive weapon. They are similar to, though much more developed than, the glands found in species of the Mustelidae family. Skunks have two glands, one on each side of the anus. These glands produce a mixture of sulfur-containing chemicals (methyl and butyl thiols), which have a highly offensive smell that can be described as a combination of the odors of rotten eggs, garlic and burnt rubber. The odor of the fluid is strong enough to ward off bears and other potential attackers and can be difficult to remove from clothing. Muscles located next to the scent glands allow them to spray with a high degree of accuracy, as far as 2 to 5 metres (6.6 to 16 ft). The smell aside, the spray can cause irritation and even temporary blindness and is sufficiently powerful to be detected by a human nose anywhere up to a mile downwind. Most predatory animals of the Americas, such as wolves, foxes and badgers, seldom attack skunks, presumably out of fear of being sprayed. The exception is the great horned owl, the animal's only serious predator, which, like most birds, has a poor-to-nonexistent sense of smell. Skunks are common in suburban areas, and frequent encounters with dogs and other domestic animals, and the release of the odor when a skunk is run over, lead to many myths about the removal of the skunk odor. Due to the chemical composition of the skunk spray, most of these household remedies are ineffective, with the exception of a peroxide formula or other remedies that break down the thiols. [READ THE REST OF THIS ARTICLE]



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