Metabolism
Metabolism is the total set of chemical reactions that occur in living cells. These processes are the source of life, allowing cells to grow and reproduce, maintain their structures, and react to their environments. Metabolism is frequently divided into two categories. Catabolic reactions yield energy, an example being the stop working of food in cellular respiration. Anabolic reactions, on the other hand, use this energy to construct mechanism of cells such as proteins and nucleic acids.
The chemical reactions of metabolism are organized into metabolic pathways, in which one chemical is distorted into another by a series of enzymes. Enzymes are vital to metabolism because they allow cells to drive desirable but thermodynamically unfavorable reactions by combination them to favorable ones. Enzymes also agree to the regulation of metabolic pathways in response to changes in the cell's environment or signals from other cells.
Tuesday, July 24, 2007
Monday, July 16, 2007
Robotics
It is the science and technology of robots, their plan, manufacture, and application.Robotics requires functioning information of electronics, mechanics, and software. A person functioning in the field is a roboticist. The word robotics was first used in issue by Isaac Asimov, in his science fiction short story "Runaround" (1941).
Although the outside and capabilities of robots vary extremely, all robots share the features of a mechanical, movable structure under some form of control. The chain is misshapen of links, actuators and joints which can allow one or more degrees of freedom. Most modern robots use open sequential chains in which each link connects the one before to the one after it. These robots are called serial robots and often look like the human arm. A few robots, such as the Stewart platform, use closed parallel kinematic chains. Other structures, such as those that imitate the mechanical structure of humans, diverse animals and insects, are relatively rare. However, the development and use of such structures in robots is a dynamic area of research. Robots used as manipulators have a finish effector mount on the last link. This end effector can be something from a welding mechanism to a mechanical provide used to manipulate the environment.
It is the science and technology of robots, their plan, manufacture, and application.Robotics requires functioning information of electronics, mechanics, and software. A person functioning in the field is a roboticist. The word robotics was first used in issue by Isaac Asimov, in his science fiction short story "Runaround" (1941).
Although the outside and capabilities of robots vary extremely, all robots share the features of a mechanical, movable structure under some form of control. The chain is misshapen of links, actuators and joints which can allow one or more degrees of freedom. Most modern robots use open sequential chains in which each link connects the one before to the one after it. These robots are called serial robots and often look like the human arm. A few robots, such as the Stewart platform, use closed parallel kinematic chains. Other structures, such as those that imitate the mechanical structure of humans, diverse animals and insects, are relatively rare. However, the development and use of such structures in robots is a dynamic area of research. Robots used as manipulators have a finish effector mount on the last link. This end effector can be something from a welding mechanism to a mechanical provide used to manipulate the environment.
Wednesday, July 11, 2007
Hardware and software design
Supercomputers using custom CPUs traditionally gained their speed over conventional computers through the use of innovative designs that allow them to carry out many tasks in parallel, as well as complex feature engineering. They tend to be expert for certain types of computation, usually numerical calculations, and perform poorly at more general computing tasks. Their memory hierarchy is very cautiously designed to ensure the processor is kept fed with data and commands at all times—in fact, much of the performance difference between slower computers and supercomputers is due to the memory hierarchy. Their I/O systems tend to be planned to support high bandwidth, with latency less of an issue, because supercomputers are not used for transaction processing.
As with all highly parallel systems, Amdahl's law applies, and supercomputer designs devote great effort to eliminate software serialization, and using hardware to speed up the remaining bottlenecks.
Supercomputers using custom CPUs traditionally gained their speed over conventional computers through the use of innovative designs that allow them to carry out many tasks in parallel, as well as complex feature engineering. They tend to be expert for certain types of computation, usually numerical calculations, and perform poorly at more general computing tasks. Their memory hierarchy is very cautiously designed to ensure the processor is kept fed with data and commands at all times—in fact, much of the performance difference between slower computers and supercomputers is due to the memory hierarchy. Their I/O systems tend to be planned to support high bandwidth, with latency less of an issue, because supercomputers are not used for transaction processing.
As with all highly parallel systems, Amdahl's law applies, and supercomputer designs devote great effort to eliminate software serialization, and using hardware to speed up the remaining bottlenecks.
Wednesday, June 06, 2007
Wherry
The Norfolk wherry is a black-sailed trader, kind of boat on The Broads in Norfolk. It is double-ended with the pole steeped well forward, tinted black with a single gaff sail. Mostly clinker-built, it would carry about 25 tons of goods.
Wherries were able to arrive at better boats just off coast and take their cargoes off to be transported inland through the broads and the rivers.
Before wherries, there was the Norfolk Keel, a quadrangle rigged, transom sterned clinker-built boat, 54 feet by 14 feet, and able to carry 30 tons of goods. The keel had been built since the middle Ages and the plan probably went back to the Viking invasion. After 1800, the Norfolk Keel (or 'keel wherry') disappeared, partly since a wherry could be sailed with fewer crew, and it had limited maneuverability and lacked speed.
A special wherry wheelbarrow was used to unpack cargo, e.g. stone, from the wherries. It was made from wood and strengthens with iron bands. It had no legs; therefore it could be rested on the 11 inches wide plank on the surface of the wherry.
The Norfolk wherry is a black-sailed trader, kind of boat on The Broads in Norfolk. It is double-ended with the pole steeped well forward, tinted black with a single gaff sail. Mostly clinker-built, it would carry about 25 tons of goods.
Wherries were able to arrive at better boats just off coast and take their cargoes off to be transported inland through the broads and the rivers.
Before wherries, there was the Norfolk Keel, a quadrangle rigged, transom sterned clinker-built boat, 54 feet by 14 feet, and able to carry 30 tons of goods. The keel had been built since the middle Ages and the plan probably went back to the Viking invasion. After 1800, the Norfolk Keel (or 'keel wherry') disappeared, partly since a wherry could be sailed with fewer crew, and it had limited maneuverability and lacked speed.
A special wherry wheelbarrow was used to unpack cargo, e.g. stone, from the wherries. It was made from wood and strengthens with iron bands. It had no legs; therefore it could be rested on the 11 inches wide plank on the surface of the wherry.
Monday, May 28, 2007
Kayak
A kayak is a little human-powered boat. It classically has a covered deck, and a cockpit covered by a spray deck. It is propelled by a double-bladed paddle by sitting paddlers. The kayak was used by the inhabitant Ainu, Aleut and Eskimo hunters in sub-arctic regions of northeastern Asia, North America and Greenland. Modern kayaks come in a wide diversity of designs and materials for particular purposes. Kayaks are frequently referred to as canoes in Great Britain and Ireland.
Traditional kayaks typically accommodate one, two or infrequently three paddlers who sit facing ahead in one or more cockpits below the deck of the boat. If used the spray deck or comparable waterproof garment attach securely to the edges of the cockpit, prevent the entry of water from waves or spray, and making it possible in some styles of boat, to roll the kayak upright again without it filling with water or eject the paddler.
Kayaks differ definitely in design and history from canoes, which are more flat-bottomed boats propel by single-bladed paddles by a kneeling paddler, even though some modern canoes may be difficult for a non-expert to distinguish from a kayak. One benefit to a kayak is that with a canoe's high bow, it is harder to paddle against the wind. As Kayaks do not have such high sides, it is easier to paddle on a breezy day.
A kayak is a little human-powered boat. It classically has a covered deck, and a cockpit covered by a spray deck. It is propelled by a double-bladed paddle by sitting paddlers. The kayak was used by the inhabitant Ainu, Aleut and Eskimo hunters in sub-arctic regions of northeastern Asia, North America and Greenland. Modern kayaks come in a wide diversity of designs and materials for particular purposes. Kayaks are frequently referred to as canoes in Great Britain and Ireland.
Traditional kayaks typically accommodate one, two or infrequently three paddlers who sit facing ahead in one or more cockpits below the deck of the boat. If used the spray deck or comparable waterproof garment attach securely to the edges of the cockpit, prevent the entry of water from waves or spray, and making it possible in some styles of boat, to roll the kayak upright again without it filling with water or eject the paddler.
Kayaks differ definitely in design and history from canoes, which are more flat-bottomed boats propel by single-bladed paddles by a kneeling paddler, even though some modern canoes may be difficult for a non-expert to distinguish from a kayak. One benefit to a kayak is that with a canoe's high bow, it is harder to paddle against the wind. As Kayaks do not have such high sides, it is easier to paddle on a breezy day.
Sunday, May 20, 2007
Hovercraft
A hovercraft, or air-cushion vehicle (ACV), is a vehicle or craft that can be hold up by a cushion of air dispossessed downwards against a surface close below it, and can in principle travel over any relatively smooth surface, such as gently sloping land, water, or marshland, while having no substantial contact with it.
Hovercraft has one or more parts of engines (some craft, such as the SR-N6, have one engine with a drive split through a gearbox). One engine drives the fan (the impeller) which is in charge for exciting the vehicle by forcing air under the craft. The air therefore must exit throughout the "skirt", lifting the craft above the area which the craft resides. One or more additional engines are used to offer thrust in order to propel the craft in the favorite direction. Some hovercraft utilized ducting to allow one engine to perform both tasks by directing some of the air to the skirt, the rest of the air passing out of the back to push the craft forward.
A hovercraft, or air-cushion vehicle (ACV), is a vehicle or craft that can be hold up by a cushion of air dispossessed downwards against a surface close below it, and can in principle travel over any relatively smooth surface, such as gently sloping land, water, or marshland, while having no substantial contact with it.
Hovercraft has one or more parts of engines (some craft, such as the SR-N6, have one engine with a drive split through a gearbox). One engine drives the fan (the impeller) which is in charge for exciting the vehicle by forcing air under the craft. The air therefore must exit throughout the "skirt", lifting the craft above the area which the craft resides. One or more additional engines are used to offer thrust in order to propel the craft in the favorite direction. Some hovercraft utilized ducting to allow one engine to perform both tasks by directing some of the air to the skirt, the rest of the air passing out of the back to push the craft forward.
Sunday, May 13, 2007
Folding boat
A Folding boat is frequently a smaller boat, typically ranging between 8 to 12 feet. This style of boat must also allow for easy lifting which require a glow weight. Folding boats are made from light weight resources such as marine plywood, aluminum or more exotic man-made materials lighter and tougher than aluminum. Folding boats fill a need for people who do not have storage gap for a full-size boat or cannot transport a full-size boat.
There are more than a few folding boat makers and folding kayak makers in the world from the USA, England and Australia with several variations and models. The handyman can also produce their own unit at home with plans or buy designing their own version.
Although there is much to be thought by the advantages of a folding boat, they are not common place in boating and aluminum and inflatable alternatives are far more common despite some folding boats having been sold for several decades.
A Folding boat is frequently a smaller boat, typically ranging between 8 to 12 feet. This style of boat must also allow for easy lifting which require a glow weight. Folding boats are made from light weight resources such as marine plywood, aluminum or more exotic man-made materials lighter and tougher than aluminum. Folding boats fill a need for people who do not have storage gap for a full-size boat or cannot transport a full-size boat.
There are more than a few folding boat makers and folding kayak makers in the world from the USA, England and Australia with several variations and models. The handyman can also produce their own unit at home with plans or buy designing their own version.
Although there is much to be thought by the advantages of a folding boat, they are not common place in boating and aluminum and inflatable alternatives are far more common despite some folding boats having been sold for several decades.
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