Mechanical Engineering

Carbon is an element. It is made up of itself. Its atomic number is 6. This means that it has 6 protons and 6 electrons.

No. Gate valves are designed to be either completely open or completely closed. Regulating flow is best done with a globe or plug valve, or certain kinds of ball valves. A gate valve left partially open will eventually wear down so that it can never be completely closed.

About 1300-1200 BC, There is some indication of rare occurrences of iron before that, but it was so scarce as to be considered a precious metal. That time period marked the end of the Bronze Age, and the start of the Iron Age.

The main danger is the pent up power of compressed air. If the tie rods on an air cylinder fail the end would fly off at some terrific speed whereas with an hydraulic cylinder as soon as the end came off the pressure would be gone even though it was much higher to start with.

Because in any real-world process, there is always uncertainty, and if you measure with enough precision you will always find variation in dimensions. Tolerances are specified so the machinist knows what is 'tolerable' and what is not acceptable. Assuming you are working in inches... A drawing dimension might be 1.50 +/- .03 . That would usually be a pretty easy tolerance to hit on a machined part. The machinist knows he doesn't need to be obsessive about this operation, and it will fit into where it is going as long as it is between 1.47 and 1.53 . He can measure it with a scale. Now, if it is 1.5000 +/.0001, it is much more difficult. The machinist needs to be very carefull here. He's going to need a good setup on good machinery, and something very precise to check the part with, in order to make a part that works. It is crucial that engineers and designers think about the tolerances they put on part drawings, because overly tight tolerances cost money, and overly loose tolerances might result in assemblies that don't work. Most of the time, the machinist does not know the context the part will be used in, so he/she shouldn't be left to make those decisions himself. When making parts on NC equipment right off CAD models, it is necessary to provide tolerance guidance to the machine shop to make sure the final part meets the need. Critical dimensions need to be identified at a minimum.

If you get more force out of a machine than what was put into it, that is mechanical advantage. Levers and gears use this principal to amplify their output.

We call material that acts in that way a thermal insulator. Sometimes we shorten it to just insulation, but we need to be clear that we're talking about thermal energy and not, say, electrical energy.

Oxygen react with carbon, carbon dioxide is formed and this compound is released as a gas.

The startup sequence of a gas turbine engine, provided that all environmental systems are working (fuel supply, battery power/pneumatic pressure etc.) are available, is basically as follows:

- energize starter

- observe RPM is increasing

- once lightup RPM is reached, energize ignition system

- open start fuel valve or (if no dedicated start fuel system present on particular machine) main fuel valve at minimum flow

- observe increase of exhaust gas temperature (EGT) or whatever combustion-related temperature is displayed on particular machine (TIT, ITT)

- once combustion is established, increase main fuel flow, carefully observing that temperature limits aren't exceeded

- monitor RPM and EGT and modulate fuel flow for smooth acceleration without excessive temperatures

- once self-sustain speed is reached, de-energize ignition system and starter

- continue to monitor RPM and temperature until idle speed is reached

- make sure that at specified RPM, the required minimum oil pressure is present

On modern engines, this procedure is programmed into a sequencer that will take care of everything until idle speed is reached. Any malfunction will cause the startup cycle to be terminated. Usually, engines equipped like this are just started by pushing a switch and observing the instruments.

A pulley system creates mechanical advantage by dividing force over a length of rope or its equivalent, that is greater in length than the maximum distance the load can travel by using the pulley system. Through the use of movable pulleys or their equivalent, a system creates a mechanical advantage through the even division of force over multiple rope strands of a continuous rope. As rope, or its equivalent, is removed from the system, pulleys, or their equivalent, allow the side of the rope to apply force to the load. As the the system contracts, the load is lifted or moved (depending on the direction of the pull). The more strands created by the configuration, the greater the mechanical advantage. This is because every strand of rope or its equivalent created by the configuration of the system will take an equal amount of length of rope removed as the system contracts. Thus if there are three strands of rope created by the system, and three units of rope are removed from the system, each strand will contract by one unit. As the strands are parallel, or function in as parallel the overall contraction of the system is one unit, moving the load only one unit for every three units of rope removed. By distributing the force needed to move the load one unit over three units of the rope, this decreases the force needed on the pulling end by 1/3. This would be a mechanical advantage of 3:1. One of the most common systems of mechanical advantage is a shoe lace system. The grommets of the system are the equivalent of movable pulleys. As lace is removed from the system, force is applied to grommet, contracting the system. The laces are much longer than the space that they are contracting, and to fully contract the space nearly all the lace must be removed, so we can clearly see that many more units of lace must be removed for every one unit of contraction in the system, thus mechanical advantage is created. Of course in a lace system friction quickly overcomes and limits the advantage created. But on the other hand the friction helps to hold the force exerted allowing you to cinch up you shoes more easily. Now with this example in mind, let's look at a more traditional pulley system. The easiest way to understand how mechanical advantage is achieved may be to focus on the geometry of the system. Specifically by focusing on how force is applied to the load and why the configuration of movable pulleys distributes force and creates mechanical advantage. Imagine a weight to which a rope is directly attached. The rope is fed though a pulley mounted on the ceiling (fixed pulley). If you were to pull the rope the weight would move up a distance equal to the length of rope pulled. This is because the rope is directly attached to the load. There is no mechanical advantage. If we want to create a mechanical advantage we must attach a pulley to the load/weight so that force is applied via the rope's contact with the movable pulley . So in the next scenario imagine the rope is directly attached to the ceiling, and is fed through a pulley attached to the load (movable pulley as the load can move). The distance from the movable pulley to the ceiling is 10 feet. Now imagine you were to grab the rope exiting the pulley (imagine the system has no slack), and raise it to the ceiling. Now you have 10 foot section of rope with both ends on the ceiling. Where does that leave the load? Since the load is connected to the system by a wheel that can travel over the rope it has not followed the end of the rope the 10 feet to the ceiling, instead it has stayed in the center of the rope, constantly dividing the distance of the remaining section of rope. The load will now be 5 feet from the ceiling (10 feet / 2 section of rope). It has move only 1 unit of distance for every 2 units the rope has moved. Therefore only 1/2 the force is needed to move the rope 1 unit. This movable pulley system therefore has a 2:1 mechanical advantage. Now we will add another pulley to the ceiling. This is a fixed pulley and will not add any mechanical advantage, but will only redirect the force applied to the system. If we add another pulley to the load we will then have added mechanical advantage. When calculating the advantage added, you must observe the movable pulleys and their relationship to the load. Imagine a system with a rope directly connected to a load. The rope travels through a fixed pulley on the ceiling to another pulley on the load and back up to a fixed pulley on the ceiling. Drawn on paper this system will have four rope strands. For calculating mechanical advantage you must not count the strand exiting the final fixed pulley as the fixed pulley does not add mechanical advantage. (if the system was to end with a pulley attached to the load you would want to count the final strand). In this scenario we have three strands of rope contributing to the mechanical advantage of the system so the advantage should be 3:1. But how can you prove this. Imagine each section is ten feet long. Thus we have 30 total feel in the system. We pull out 10 feet of rope, how far has the load traveled? Well, we know we now have 20 feet of rope in the system distributed over 3 equal strands of rope. That would make each strand approximately 6.66 feet long. The load would therefore be approximately 6.66 feet from the ceiling or 3.33 feet from the ground (10 - 6.66). By traveling only 3.33 feet for 10 feet of rope removed from the system we have 3:1 mechanical advantage ratio (10:3.33). A final thought exercise to intuitively understand what can be a very unintuitive process. Imagine a 10 ft tall pulley system. Now focus on the amount of rope in the system. If you have three strands going back and forth you will have 20 to 30 feet of rope in the system (depending on if the final pulley is attached to the load or a fixed point). If you have four strand you'll have 30 to 40 feet. The particular amount is not important. What is important is to see that the only way the load can travel the 10 feet to the top of the pulley system is for nearly all the rope in the system to be removed be it 20, 30, 40, 50... ect. The more rope that must be remove/the more strands that divide the amount removed, the greater the division of the force over the rope and the less force is required on the pulling end of the system. Of course this is a basic pulley system. If you attach pulley systems to pulley systems (piggy back systems) you can begin doubling forces quickly, and strands need not be equal in length for their dividing power to function. Z rigs, trucker's hitches, and others create mechanical force through attaching or creating a movable pulley to/on the rope. The overall geometry of the systems and the relationships of elements stay the same as does the reason for the mechanical advantage. It is also important to note that there are configurations where a pulley or its equivalent may not be "movable", but mechanical advantage is created. Imagine multiple pulleys fixed to a ceiling and floor of a room. If one end of a cable was fixed to either the floor, ceiling or one of the pulleys and the system was threaded, it certainly would be creating a mechanical advantage. Though all pulleys are technically "fixed" the opposition force is magnified just as in any other system, and depending on the strength of the cable, ceiling, or anchors, one element may eventually fail because of the tension in the system. The amount of tension in the system is created though the mechanical advantage of the configuration, and though nothing may move but the cable, magnified force is applied to the elements of the system. In summary, it may be helpful to focus on the geometric relationships in pulley systems to better and more intuitively understand the way in which they create mechanical advantage.

• It involves a configuration the combines strength and productivity. The designing uses SAE steel grades (essentially an amalgamation of carbon and alloy steels) which renders the framework strong yet complex. It ensures that any beam, strut or tie ends only undergo tensional or compressional forces.
  

Elasticity is the capability of an object to return to its former shape once a load inducing strain is removed. If you were to drop a steel ball on a very hard surface, it would probably bounce higher than that of rubber. If you drop it on a softer surface, because it would deform less, then the surface it is to bounce off will be the one deforming, so the bounce would be a function of the elasticity of the floor, not of the ball.

A strand of silk is indeed stronger than a steel wire of the same diameter. The reason is that metal uses metallic bounds which is not as strong as the covalent bounds in a macro-molecule like the ones in silk. This also explains why Kevlar, carbon fiber, and carbon nanotubes are also stronger than steel.

Youngs Modulus of steel is more than youngs modulus of rubber

$211,600 - primary care. For a specialist, the average was $281,000.

if you dont know what bhp is, its brake horse power, it is worked out by multiplying the torque by the numberb of cylinders (i think)

ps. 1 horse has 0.7bhp, the bloke who worked this out assumed a horse has x2 strength as a pony which drew his carriage and this stuck, thhat is why there are many variations of horsepower/brakehorsepower now

Diesel engines run much higher compression than petrol engines. The higher compression makes the air in the cylinder so hot that the fuel self ignites. A petrol engine doesn't get warm enough for self ignition, so you have to add a spark from the spark plug to ignite the fuel.

Gate Valve is

* Well sealed * Causes a low pressure drop * Don`t Cause hammering

* serve Wide size Range * Wide range of temperature

* Wide range of temperature Ball Valve is

* Limited in usage for Temperature cautions * Needs a big Operating Torque for big Sizes

Yes, the mild steel under the plating is magnetic. The coating only prevents corrosion.

Can you tell that sameone is agreing with you

There is a tremendous importance of welding in engineering, there are even such things as welding engineers ( I am one). Welding is what holds the majority of structures together--bridges, cars, tractors, cranes, buildings, etc...If any engineer does not have a good understand of this very popular joining process major problems can exist, such as failures from designing a joint that is un-weldable. Most companies these days are trying to hire welding engineers to help with these problems. Welding can get very specialized with more technical metals and applications.

this is the mechanism in which every part returns quickly to its original position without any exhausation and after comong back it chills.................

just chill dhondo

no need to answers such ????????????????s

hahaha

limit, unilateral, and bilateral

I think it is IS-2062 E410/Fe 540. You can also check IS-2062 E350/Fe490.

Brushes transfer electricity to the commutator which is connected to the winding on the armature. The brushes and commutator form a electrical connection that is good when the brushes are stationary and the commutator is spinning. The commutator on a DC motor is sectioned to power different windings at different times, creating moving field necessairy to pull the armature off a direct current.

the formula of B.H.N is give less accurate value when the indentation is more.

It has only one scale And applied only to some materials.