how do typhoons form?
Windmill Farms answers:
A typhoon is the same thing as a hurricane or Tropical Cylone.
A tropical cyclone is a warm-core, low pressure system without any “front” attached, that develops over the tropical or subtropical waters, and has an organized circulation. Depending upon location, tropical cyclones have different names around the world. In the:
Atlantic/Eastern Pacific Oceans – hurricanes
Western Pacific – typhoons
Indian Ocean – cyclones
Regardless of what they are called, there are several favorable environmental conditions that must be in place before a tropical cyclone can form. They are:
Warm ocean waters (at least 80°F / 27°C) throughout a depth of about 150 ft. (46 m).
An atmosphere which cools fast enough with height such that it is potentially unstable to moist convection.
Relatively moist air near the mid-level of the troposphere (16,000 ft. / 4,900 m).
Generally a minimum distance of at least 300 miles (480 km) from the equator.
A pre-existing near-surface disturbance.
Low values (less than about 23 mph / 37 kph) of vertical wind shear between the surface and the upper troposphere. Vertical wind shear is the change in wind speed with height.
Given that sea surface temperatures need to be at least 80°F (27°C) for tropical cyclones form, it is natural that they form near the equator. However, with only the rarest of occasions, these storms do not form within 5° latitude of the equator. This is due to the lack of sufficient Coriolis Force, the force that causes the cyclone to spin.
The seedlings of tropical cyclones, called “disturbances”, can come from:
Easterly Waves: Also called tropical waves, this is an inverted trough of low pressure moving generally westward in the tropical easterlies. A trough is defined as a region of relative low pressure. The majority of tropical cyclones form from easterly waves.
West African Disturbance Line (WADL): This is a line of convection (similar to a squall line) which forms over West Africa and moves into the Atlantic Ocean. WADL’s usually move faster than tropical waves.
TUTT: A TUTT (Tropical Upper Tropospheric Trough) is a trough, or cold core low in the upper atmosphere, which produces convection. On occasion, one of these develops into a warm-core tropical cyclone.
Old Frontal Boundary: Remnants of a polar front can become lines of convection and occasionally generate a tropical cyclone. In the Atlantic Ocean storms, this will occur early or late in the hurricane season in the Gulf of Mexico or Caribbean Sea.
Once a disturbance forms and sustained convection develops, it can become more organized under certain conditions. If the disturbance moves or stays over warm water (at least 80°F), and upper level winds remain weak, the disturbance can become more organized, forming a depression.
The warm water is one of the most important keys as it is water that powers the tropical cyclone (see image above right). As water vapor (water in the gaseous state) rises, it cools. This cooling causes the water vapor to condense into a liquid we see as clouds. In the process of condensation, heat is released. This heat warms the atmosphere making the air lighter still which then continues to rise into the atmosphere. As it does, more air moves in near the surface to take its place which is the strong wind we feel from these storms.
Therefore, once the eye of the storm moves over land will begin to weaken rapidly, not because of friction, but because the storm lacks the moisture and heat sources that the ocean provided. This depletion of moisture and heat hurts the tropical cyclone’s ability to produce thunderstorms near the storm center. Without this convection, the storm rapidly diminishes.
in what decade did elevators become automated, ( self-leveling), without the need of an operator?
Windmill Farms answers:
The history of power elevators in the U.S. Began in 1850, when a crude freight hoist operating between two adjacent floors was installed in a New York City building. In 1853, at the New York Crystal Palace exposition, the American inventor and manufacturer Elisha Otis exhibited an elevator equipped with a device called a safety to stop the fall of the car if the hoisting rope broke. In this event a spring would operate two pawls on the car, forcing them into engagement with racks at the sides of the shafts so as to support the car. This invention gave impetus to elevator construction. Three years later the first passenger elevator in the U.S., designed by Otis, was installed in a New York City store. In these early elevators, a steam engine was connected by belt and gears to a revolving drum on which the hoisting rope was wound. In 1859 an elevator raised and lowered by a vertical screw was installed in the Fifth Avenue Hotel in York City. In the 1870s the rope-geared hydraulic elevator was introduced. The plunger was replaced in this type by a relatively short piston moving in a cylinder that was mounted, either vertically or horizontally, within the building; the effective length of the stroke of the piston was multiplied by a system of ropes and sheaves. Because of its smoother operation and greater efficiency, the hydraulic elevator generally replaced the type with a rope wound on a revolving drum.
The electric motor was introduced in elevator construction in 1880 by the German inventor Werner von Siemens. His car, carrying the motor below, climbed its shaft by means of revolving pinion gears that engaged racks at the sides of the shaft. An electric elevator was constructed in Baltimore, Maryland, in 1887, operated by an electric motor turning a revolving drum on which the hoisting rope was wound. Within the next 12 years, electric elevators with worm gearing connecting the motor and drum came into general use except in tall buildings. In the drum elevator the length of the hoisting rope, and therefore the height to which the car can rise, are limited by the size of the drum; space limitations and manufacturing difficulties prevented the use of the drum mechanism in skyscrapers. The advantages of the electric elevator, however, including efficiency, relatively low installation costs, and virtually constant speed regardless of the load, spurred inventors to search for a way of using electric motive power in skyscrapers. Counterweights creating traction on electrically driven sheaves solved the problem. Since the introduction of electric motive power for elevators, various improvements have been made in motors and methods of control. At first, single-speed motors only were used. Because a second, lower speed was desirable to facilitate leveling the car with landings, low-speed auxiliary motors were introduced, but later several systems were devised for varying speed by varying the voltage supplied to the hoisting motor. In recent years devices for automatic leveling of cars at landings are commonly used. Originally the motor switch and the brakes were operated mechanically from the car by means of hand ropes. Soon electromagnets, controlled by operating switches in the car, were introduced to throw the motor switch and to release a spring brake. Push-button control was an early development, later supplemented by elaborate signal systems.
If you know alot about tidal energy then you should should look at this ………………please?
Please tell me everything about tidal energy including
1.how does it work
3.how many are in the world
4.how much energy does it produce
5.history of development
7.uses of electricity produced
8.what is the natural source of energy
If you can help me I will be so great full………i will defently give the person 5 stars and i will help them aswell with their questions
Windmill Farms answers:
It’s a big piece, but I hope you get all the info u need =)
1. The process of harnessing energy from the ocean’s tide is very similar to that of harnessing water through a hydroelectric dam. However, the dam needed for this process is much larger. Installed within the dam are turbines. The movement and flow of the tide in and out from the shore is then used to turn those turbines and create the power needed.
(2,3,4 question) There are two ways at present of using tidal power:
Barrage systems: This system, built like a dam across a river, holds back the water till the tide has gone out, then uses the potential energy of the water to turn turbines in the barrage. This is an expensive system with many disadvantages.
Tidal Stream systems. This consists of using turbines, rather like wind turbines, to use the kinetic power of the moving water to generate electricity. This is easier and cheaper to install.
There are three Barrage systems operating throughout the world.
One large 240 MW plant on the Rance River in France, and two small plants,
one in the Bay of Fundy in Canada, and
another in Kislaya Guba in Russia.
There is only one Tidal Stream system working commercially:
A fullsize turbine prototype, SeaGen, was installed in Strangford Lough in Northern Ireland in 2008, with a capacity of 1.2 MW.
A large number of smaller tidal stream pilot schemes are being trialled.
-In Hammerfest, Norway a turbine, generating 300 kW, started in 2003.
-A 300 kW Periodflow marine current propeller type turbine was tested in Devon, England in 2003.
-Since April 2007 a prototype project in the East River in New York City has been running.
-An Open-Centre Turbine, has a prototype being tested at the European Marine Energy Centre (EMEC), in Orkney, Scotland.
-A Gorlov turbine, an improved helical design, is being prototyped on a large scale in S. Korea.
-Neptune Renewable Energy has developed Proteus which uses a barrage of vertical axis crossflow turbines for use mainly in estuaries.
-During 2003 a 150kW oscillating hydroplane device, the Stingray, was tested off the Scottish coast.
-Successful commercial trials of highly efficient shrouded tidal turbines on the Gold Coast, Queensland, Australia in 2002.
-Shrouded turbines are being installed for a remote Australian community in northern Australia, two small turbines will provide 3.5 MW.
-Another larger 5 meter diameter turbine, capable of 800 kW in 4 m/s of flow, is planned as a tidal powered desalination showcase near Brisbane Australia in October 2008.
-The Hydro Venturi, is being tested in San Francisco Bay.
-In April 2008, a turbine-generator unit (TGU) prototype was successfully tested at Cobscook Bay and Western Passage tidal sites near Eastport, Maine.
-Trials in the Strait of Messina, Italy, started in 2001 of the Kobold concept.
(4,6,7) Tidal energy use harnesses the water flow created primarily by the moon orbiting the Earth. As water is pulled toward the gravity of the moon, currents are created that can turn generator turbines.
Volumes have been written about tides and their effects on our planet. This Wikipedia Tides article is a good primer on the subject. It is noteworthy that all tidal energy does not come from the moon. About a third of it comes from the gravitational influence of our sun.
The interplay of gravitational fields of the moon and the sun combined with the rotation of Earth, creates a twice a day ebb and flow of the tides of our world that varies in height and strength.
Those variations in height and strength are completely predictable. As we’ll see later, that predictability is an important aspect of tidal energy use.
Though renewable, practical tidal energy use will be limited. Tidal flows are global, but the key to using them economically is finding either natural high tidal flow areas, or large tidal basins that can be easily dammed to channel water through turbines. _________________________________________________________________
ENVIRONMENTAL FRIENDLINESS –
Tidal energy use involving dams creates many of the same environmental concerns as damming rivers. Tidal dams restrict fish migration and cause silt build up which affects tidal basin ecosystems in negative ways.
Systems that take advantage of natural narrow channels with high tidal flow rates have less negative environmental impact than dammed systems. But they are not without environmental problems.
Both systems use turbines that can cause fish kills. But these are being replaced by new, more fish friendly turbines. The art and science of environmentally friendly hydro engineering is well advanced and will certainly be applied to any tidal energy project.
But even with dams, the environmental impact of tidal energy projects may prove to be smaller than our use of any other energy resource. Economics will severely limit the number of tidal energy projects. ______________
“How should we select different gears for different applications”?
Windmill Farms answers:
these gears are used mainly for slow speeds to avoid excessive noise and vibration.
+ hand or powered winches
+ wind up clocks
+ washing machine
The most commonly used spiral beveled gear set is the ring and pinion gears used in heavy truck differentials. Bevel-type gears are also used for slow-speed applications that are not subject to high impact forces. Handwheel controls that must operate some remote device at an angle use straight bevel gears. A good example of bevel gears is seen as the main mechanism for a hand drill. As the handle of the drill is turned in a vertical direction, the bevel gears change the rotation of the chuck to a horizontal rotation. The bevel gears in a hand drill have the added advantage of increasing the speed of rotation of the chuck and this makes it possible to drill a range of materials.
The bevel gears find its application in locomotives, marine applications, automobiles, printing presses, cooling towers, power plants, steel plants, defence and also in railway track inspection machine. They are important components on all current rotorcraft drive system.
Spiral bevel gears are important components on all current rotorcraft drive systems. These components are required to operate at high speeds, high loads, and for an extremely large number of load cycles. In this application, spiral bevel gears are used to redirect the shaft from the horizontal gas turbine engine to the vertical rotor.
The most common use for the worm gear is in applications where the power source operates at high speed and the output is at slow speed with high torque. Many steering mechanisms use a worm gear connected to the steering shaft and wheel and a partial (sector) gear connected to the steering linkage. Small power hand tools frequently use a high-speed motor with a worm gear drive.
Helical spur gears are widely used in transmissions today because they are quieter at high speeds and are durable.
Rack And Pinion:
These gear sets can provide control of arbor presses and other devices where slow speed is involved. Rack and pinion gears also are commonly used in automotive steering boxes.
Planetary gears are widely used because each set is capable of more than one speed change. The gear load is spread over several gears, reducing stress and wear on any one gear.
The most common use for hypoid gears is in modern differentials. Here, they allow for lower body styles by lowering the transmission drive shaft.
Herringbone gears are best suited for quiet, high-speed, low-thrust applications where heavy loads are applied. Large turbines and generators frequently use herringbone gears because of their durability.
Crown wheels are used in motorcycle automotive gearboxes. It is also used in mechanical clocks. The clock consists of a crown wheel, rotated by a falling weight, whose teeth drive the pallets of a verge backward and forward. This verge is connected to an arm with a hammer on the end that struck the bell.
How to build a drawbridge?
I need to build a drawbridge for a school project (modern ones, not the one used in the Middle Ages) that is powered by a hydraulics system and consists of at least one simple machine using only syringes and pieces of wood and popsicle sticks. Could someone please give me a few ideas?
Windmill Farms answers:
Here are a couple of sketches showing 2 different types of drawbridge.
I assume the syringes are the hydraulic cylinders, and that you’ll work the plunger on the master syringe manually.
The bascule type normally has a giant gear centered on the main pivot, and the motor has a smaller gear to drive it, but I’ve shown a lever arrangement (that’s your simple machine). You could use the rack and pinion arrangement, too.
The lift span might be easier to build, since you don’t have to get all the lever geometry right, but if you can only use popsicle sticks, you might have a hard time with the gears. You might also use a string wound around a drum instead of a rack and pinion. If you can’t use string, though, you can’t do the lift span at all.
A third type is the swing span, where there’s a center support with a span balanced on it (like a T), and the span rotates 90 degrees on a vertical axis. This could also be done with a lever, but the center support would have to be large in diameter to house the slave syringe, so it probably wouldn’t be practical.
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