- Category: Engineering
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The engine's cooling system works with the combination of several components that work together to cool the engine. Read on to find out more on how en engine's cooling system works.
Why Cooling System is Necessary
The air fuel mixture burning in the engine cylinders may reach temperatures of 4000 Degrees F, due to which engine parts become very hot. However, walls of engine cylinders should not become hotter than approximately 500 degrees F, since higher temperatures can cause failure of lubricating oil, and loose its lubricating ability. The cooling system is used to prevent overheating of parts, by removal of heat from the engine.
Functions of Cooling System
Major function of the cooling system, is to keep the engine at its most efficient temperature, at all speeds and operating conditions. Heat is produced in the engine by burning of fuel, which must be removed, before it damages the parts of engine. It also assists in normalizing the engine temperature as soon as possible.
Major Parts of the Cooling System
Water Jackets: The cylinder block and cylinder head have internal passages or water jackets that surround the cylinder and combustion chamber. Water mixed with antifreeze, flows through the water jackets, taking away heat, due to which the metal parts are cooled.
Water Pump: Water pump is driven by the engine, which pushes the hot coolant out of the water jackets and through the radiator. It is attached to the front of the engine, and driven by a belt from the crankshaft pulley. As the impeller rotates, the curved blades draw coolant from the bottom of the radiator, and force the coolant through the pump outlet to the water jackets.
Thermostat: A thermostat valve known as thermostat controls the flow of the coolant. When the engine is cold, the thermostat closes to prevent the flow of coolant to the radiator. This keeps all heat in the engine, due to which it warms up quickly. As the engine warms, the thermostat opens to allow the coolant flow through the radiator.
Radiator: The radiator is a heat exchanger, with two sets of passages. One set is for the coolant, and the other set is for outside air. It consists of a radiator core, inlet tank and outlet tank. The coolant looses heat to the passing air in the radiator. Then the coolant flows back through the water jackets to again pick up heat. The coolant continuously circulates between the water jackets and the radiator.
Fan: A fan pulls or pushes outside air through the radiator. This improves the engine cooling, especially at idle and low speed. The fan can be either a mechanical fan or an electric fan.
Functioning of the engine cooling system is indicated by an indicator on the instrument panel, which the driver should observe frequently, so as to prevent damage to the engine in case of failure of cooling system parts.
- Category: Engineering
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How does an airplane stop? An airplane stops when a combination of a number of things take place in sequence and/or together. Generally, commercial planes have 3 systems to stop the aircraft, described below.
The first system that helps in stopping the airplane is called flaps. Look at the image at bottom and see how flaps are extended. These are extended before 5-10 minutes of descending. The flaps help the airplane to decelerate, thus reducing the speed before touchdown. Pilots can extend the flaps to any configuration to meet the demand of deceleration. The lower percentage of the flaps helps to give the plane a lift but as a certain percentage is crossed (normally 35 %), the drag starts to prevail over lift, causing the airplane to slow.
Spoilers, also called air brakes, aileron or speed brakes is another system to slow down an airplane before the touchdown and just after landing. Spoilers apply a backward force on the airplane's wings, with the help of air to slow the airplane. If you've ever looked out at a wing just before landing, you have probably seen them but only certain spoilers are opened in the air while others are locked out. See how spoilers are pointing up on the wings, in the right picture.
The second system of slowing down an airplane is called reverse thrusters, which comes in action right after the airplane wheels touch the ground. The purpose of reverse thrusters is to redirect engine thrust to help stop the airplane. Reverse thruster, as the word says, redirects the airflow to some other direction. See in the image at right how the frame that surrounds the engine looks if it's fallen apart. This forces the air that's coming out of the engine to be pushed up and down, altering the engine thrust. This in turn slows the airplane significantly.
You can see when the reverse thrusters are in action. They normally operate until the airplane is slowed down to a manageable speed. The noise at that time is somewhat intense for a few seconds. You can also see the water or dust droplets kicking out of the engine. The power of the engines is clearly heard and seen. This is an amazing experience. Because airplanes are getting bigger and heavier and just need more advanced braking technology, all of the newer airplanes have them.
The third system in the process of slowing and stopping an airplane is wheel brakes. Wheel brakes are applied gradually once both the rear and front wheels have touched on the runway. Commercial airplanes have at the minimum, wheel brakes for stopping. If the wheel brakes were just used to stop the airplane, it would take a very long runway length and the stopping interval would be greater. Some airplanes have auto brakes and the pilot can set their intensity to low, medium or high. Auto brakes are also used during take off and applies braking automatically in the event the take off is aborted for some reason.
Hope this answered well the question "how do airplanes stop", "how does an airplane stop"
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- Category: Engineering
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The characteristics of a product manufactured are largely determined by the engineering properties of the material used. Therefore, the engineering properties should be thoroughly analyzed before the finalization of the material selection
Importance of Engineering Materials
Different engineering materials can be used for the manufacture of various products, and the selection of the engineering material depends upon their mechanical properties, the type of product, functions desired, quantities to be manufactured and numerous other engineering factors. Therefore, all these factors must be considered in the design of a product, since the quality and characteristics of the final product manufactured will be affected by these factors.
What Are Mechanical Properties
Mechanical properties forecast the behavior of particular materials when subjected to specific loads, under certain conditions. The mechanical properties are determined by the performance of test and procedures, utilizing test equipment in a laboratory. The important mechanical properties that should be considered in the manufacture of engineering products are mentioned below:
The yield strength of a body is the stress at which plastic deformation of the material starts. Before reaching the yield point, elastic deformation will occur, and the material will be restored to its earlier shape on the removal of the stress. After crossing the yield point, certain deformation will be perpetual and cannot be reversed. The information concerning the yield point is essential in the design of a component because it signifies the maximum load limit, and any further increase may cause failure of the component. The property of yield strength is essentially used in the manufacture processes, such as forging and rolling.
The tensile strength of a material indicates the likely behavior of the material when subjected to tensile loads, and is utilized in the determination of other important engineering properties such as elongation, yield strength, and elasticity. The tensile strength of a material is determined by the loading of a specimen, and measurements of the load and the elongation of the specimen.
Ultimate Tensile Strength
The ultimate tensile strength of a substance is the greatest stress that it can withstand, and it indicates the amount of stress at the breaking point of a material, after which the material may fail, or the structural strength of the material may not be maintained.
Other engineering properties that should be considered in the selection of a material are ductility, resilience, hardness, and plastic deformation.
- Category: Engineering
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Geneva Auto Show History
Geneva Auto Show commenced in year 1905, and it is a popular spot for the significant world debuts. Jaguar has brought out some of its most famous models at Geneva auto shows. In 1951, it presented the XK120 coupe, and 10 years later E-Type was introduced. In 1971, Lamborghini Countach drew the concentration of the participants of the show. After 10 years, in 1980 Audi quattro made its world debut, followed a year later in 1981 by the Volkswagen's Scirocco coupe.
Geneva Auto Show is organized every year in Geneva. The limelight of the show is expected to be the greener technology, for which a complete exhibition area has been devoted to green autos, including those with lower fuel consumption and new technologies. It will include more than 100 world debut appearances.
Major automakers of the world are participating in the show, with their most modern products being displayed. The aim will be to attract the customers, who have reduced in number considerably due to global recession. The show is expected to attract more than 700,000 visitors.
Around 30 thrilling world presentations are expected to be in the show, including the Cabriolet by Fiat, wonderful Mercedes-Benz E-class car, Audi's TT RS, with a turbocharged engine of capacity 2.5-liter, 300-hp, and the BMW 5-series GT.
Volvo is displaying seven extra clean diesel automotive, while the Swiss design firm Protoscar is introducing an environment friendly sports car called Lampo. Porsche will display their new 911 GT3 and Cayenne diesel SUV. Volkswagen have claimed a growth of 15 percent in year 2008, and a net profit of 4.75 billion, but the year 2009 is not predictable. They have started sub Compact Polo, which has a weight which is 7.5 per cent less than previous model.
Increase in Curiosity
The Geneva Motor Show has the show floor, which is easy to navigate. In one big hall, there are two levels of displays. Almost everything can be seen on the show floor. Most of the major manufacturers have large displays, and the and small volume specialty builders and designers, have arranged smaller stands, which may not be seen in other auto shows. The most debuts, or the biggest attendance, is not seen in the Geneva Motor Show, but each year, the interest increases from every major auto manufacturer. Both production and concept vehicles, can be seen from every corner of the world.
- Category: Engineering
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We read a lot in papers that fully constructed buildings and towers fall, resulting in innumerable deaths. There are various reasons for construction failures, which include the following:
Employment of Unprofessional Workers
Usually the workers who are involved in a construction project are hired on contractual basis. Since they are not permanent employees they are not granted enough time to work well and to screen their work.Sometimes people who have never been involved in a construction project are enrolled in the work. There is not much guidance given to them in areas of mixing and cement application and doing other construction work. It is assumed that workers are quite aware of their job requirements. As it is not a white collar job thus there is nothing like interview sessions.
Inadequate Material Standards
As mentioned earlier, construction projects are on contractual basis so low cost materials are bought to save in financial terms. It is obvious that cement is the most important component in the construction process. Low quality cement is cheap but it causes a huge decline in the standard of the constructed building. The time for wear and tear is reduced and the building texture becomes more vulnerable to factors like dust and train. As a result the outside texture of constructed building stats to erode at a very quick rate and with the passage of time, the overall structure becomes weaker and weaker. Hence ultimately the building falls resulting in irrecoverable human loss.
Some construction companies stress on the quantity factor in stead of the quality. They have multiple projects at a time. Their goal is to finish the maximum number of projects to maximize their monetary belongings. As a result they are careless in areas like product quality and process monitoring. A construction project deals with the lives of various people who reside in these buildings for years and years. Hence a construction company should work sincerely and with a dedicated approach to serve these people.
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