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Engineering
Engineering is an art and profession devoted to designing, constructing, and operating the structures, machines, and other devices of industry and everyday life.
5,839 Questions
What technologies were developed in China during the Zhou dynasty?
For many centuries, Chinese farmers had to depend on rain to water their crops. Under Zhou kings, the Chinese developed new systems to irrigate the land. With a better water supply, farmers were able to grow more crops than ever before.
China's trade also expanded. Archaeologists have found pieces of Chinese silk in central Asia and as far away as Greece.
What is the difference between Dbi and Dbm?
There are a few terms that need to be understood. [dBm,dBd,dBi and dB] For antennas, a common reference unit is the dBi, which states the gain of an antenna as referenced to an ISOTROPIC source. An Isotropic source is the perfect omnidirectional radiator, a true "Point Source", and does not exist in nature. Consider it a source which is the center of the sphere and the energy is coming equally out of it as a sphere. Now in reality nothing like that exists. It's also 2.41 dB BIGGER than the next common unit of antenna gain, the dBd, When you convert that to a real antenna.
So a simple dipole antenna has a gain of 2.41dBi, and a gain of 0dBd, since we're comparing it to itself.
Now lets talk about dBm, dBm is not is reference to anything else but the used as an actual gain ( say amplifiers ) , P(dBm)=10*LOG(1000*Power in milliwatts,10), an amp with an output of 30dBm puts out 1 Watt. It is not in refernce to two power level but directly correlating the gain of a device.
Now when you talk about a dB it is a relative measure of two different power levels. 10log (p1/p2, 10).
How do you convert 12.3 grams per horsepower hour to pounds per hour for a 67 horsepower engine?
The number 12.3 grams per horsepower hour is very low. For a diesel engine, the fuel consumption is about 181 grams (of diesel fuel) per horsepower hour. If the 12.3 gram number were right, you just multiply by 67 and get 824.1 grams per hour, or 0.8241 kilograms, multiply by 2.204 pounds per kilogram and and get about 1.8 pounds per hour. This number is too low, it is about 1/3 of a gallon.
So, where does the 12.3 number come from?
I am fully qualified to answer this question.
Stephen G. Margolis, PhD in Engineering Science
silogram@alum.mit.edu
Judging by the way the question is asked, I am assuming you are looking to find the emission factor and emission rate on a diesel engine to obtain a permit, rather than determine consumption. If this is the case, convert 12.3 grams(guessing that is the nitrogen oxides output) to .02712 pounds, and that gives your emission factor. Now multiply that by 67hp to get 1.817 pounds per horsepower hour, and that would be your emission rate.
Ian,
Facility Manager who occassion has to apply for permits
There are a number of components in any circuit and their job is to restrict the flow of electrons and reduce the current or voltage flowing by converting electrical energy to heat. In other terms, electronics control the electrical circuit. Electric charge is nothing but the flow of electrons from one object to another. The working of the microwave is the example of how electronics work. In a microwave, electricity provides the power that generates high-energy waves that cook your food and electronics controls the electrical circuit that does the cooking.
How do you make internal and external threads on a metal bar or rod?
Google the following: "tap and die"
It matters less what you made and more what tools (ex. software tools) you have experience with, and whether they apply to the new product.
Of course you would have to show that you know something about guitars, so that they know you would make a good product.
There are technically two types of "turbo coolers".
1. A radiator device to reduce the temperature of the compressed intake air after it's left the Turbo housing and before it reaches the engine. This is an Intercooler. Air heats up when compressed (look up the Ideal Gas Law) but cool air is denser thus carries more oxygen per unit volume. Since the fuel air mixture for combustion is tied to oxygen availability more oxygen per unit volume is desired. The Intercooler reduces the intake air temperature thus boosting combustion efficiency and reducing side effects like pre-ignition.
2. An automatic device to shut the turbocharged engine off after it has idled for several minutes. This allows the turbo housing to slowly drop in temperature from an active state to the lowest running state prior to shutdown. These devices are simply called a "turbo timer". Allowing the turbo to cool slowly extends the life of the turbo by reducing thermal stress. With some turbocharged engines such as in light aircraft this idle cooldown is mandatory.
What is the formula of calculating boiler capacity through heating surface?
hi i am kashif iqbal, u asekd that how can we calculate the capacity of biler through heating surface its a very simple for example a boiler having heating surface of = 1425 sq ft applying thumb rule = 1425/260=5.48 tons
Wiring sound and light define the following polarity of the screw colors brass bronze silver green?
Brass (or bronze) is the "hot" wire, (Black, red, or blue) silver is for the neutral (the white wire) and green is for, well, the green or bare wire
Blaniers Test is used in electronics to establish and locate short circuits and/or open circuits in cabling systems. It is a simple continuity test.
How long dies it take a boat traveling 40 km an hour to cross a lake that is 2.0 km wide?
Assuming that the boat accelerates from 0 to 40kph instantly and travels in a straight line across, 3 minutes.
Welding rods are fillers that add to the molten pool of metal. They are usually stronger than the metals being fused. In arc welding, they have a coating that burns and creates a shield around the puddle.
welding rods are used for weld two pieces of metal together, or to cut metal if you have big enough rods and enough amps.
Purpose of a guillotine foot model?
A guillotine was used during the french revolution to chop heads off the rich and royal.
A foot model could have the purpose of chopping feets off. (Makes me ponder if this has actually been made for this particular purpose)
If it is infact a smaller model only, then its purpose is probably more for display and "education" rather than actual use.
The guillotine is by most people considered to be a gruesome and inhumane tool.
Facts is that it provided a quick death, although the waiting time before execution must have been devastating thoughtwise.
Not that I condone such methods of killing or disabeling people as the outcome is most permanently even if you infact might be innocent of the crime charged with.
Some tiny models have been made to cut off the tips of cigars before you light them.
What does DWELL mean when talking about cams?
Well the dwell angle is the number of degrees of rotation from the cam (during which the points are closed) During each rotation of the cam, the points must open and close once for each cylinder.
Hope this helps x
What is an engineering job that starts with the letter s?
A software engineer is a person who applies the principles of software engineering to the design, development, maintenance, testing, and evaluation of the software that make computers or other devices containing software work.
What are some engineering jobs that start with the letter z?
Some engineering careers that start with Z:
- Zoning engineer
- Zoo operations engineer
- Zinc plating machine engineer
- Zos systems engineer
- Zainet developer engineer
Who invented the railroads you use today?
George Stephenson, around 1825. The 4' 8 1/2" gauge was used by horse drawn wagons in mines for years before and was adopted as standard across the USA, UK and most of Europe. Other gauges were tried and dropped, in favour of standardisation.
* Added - Although George was responsible for standardizing the railroad tracks and advancing railroads, he was not the inventor of the locomotive or of the railroads. The recognized locomotive inventor is Richard Trevithick in 1803, but his invention relied on inventions of many people before him as well. The first railroads date to the 1500's and many people were responsible to advance them to what they are today.
PN is a short term for "pressure rating of a pipe" PN depends on wall thickness, diameter and material type.
A PN 16 pipe is one that can withstand 16 bar (1.6 megapascals or about 232 psi) at 20 degrees c.
If you want it interms of height of equivalent water column, 1 bar =10.2 m of height water column at 20 deg C, this a PN 16 pipe can withstand 16*10.2=163.2 m of water head (static+dynamic).
Is there any steam locomotives left at Barry scrapyard?
No. The last 10 (The Barry Ten) were removed into the care of Vale of Glamorgan Council. Two have subsequently been restored and the last 8 are stored in "scrapyard condition" at the Barry Island Railway.
Was Alexander neckham the inventor of the mirror?
Alexander Neckham was born in 1157 and died in 1217; he received an excellent Church education and became a clerk in minor orders and a school teacher. Later he joined a community of Augustinian canons and was elected abbot in 1213.
He wrote several important manuscripts, mostly around 1180; these include "De Nominibus Utensilium" (regarding the names of tools), which is much more than the title implies. It covers clothing, furniture, tools, the contents of a church, how to build a castle, what to grow in a garden, the component parts of a plough, ship, loom and cart and much more. Other works are "De Naturis Rerum" (on the nature of things) and "Corrogationes Promethei". He was an observer and a recorder of the world around him.
As far as I can discover, Neckham did not invent anything - he simply recorded lists of things, how things were put together and so on. In "De nominibus utensilium" he describes lead-backed glass mirrors for the first time in history, but he was simply recording what others had devised, not what he himself had produced.
Mirrors have existed since Ancient Egyptian times; the earliest were made of highly polished bronze. They were certainly known long before Neckham's time.
Laser light is used whenever it is important that all of the light rays are in phase with each other (when the beam is coherent)
Coherence in a light beam helps it travel large distances without spreading significantly. Thus, it is used for laser pointers, so you can point across the room and still make a 3mm dot on the wall.
Coherence in the beam also allows information to be retrieved by interferometry. Splitting the laser beam, sending one half to a target and letting the other go straight, then recombining the two can give extremely accurate measurements of distance from the receiver to the target.
A variation of this procedure is used to produce holograms.
Answer:Lasers are often used in communications since it is possible to send a signal through many miles of glass fiber (over 180 miles) without having signal amplifiers or repeaters. Lasers can also send signals through the air or through space but this is not generally used since laser beams travel in straight lines and cannot follow the curvature of the earth without using a glass fiber. It is also difficult to aim a communications laser accurately at a distant moving target while radio waves illuminate a much larger area.Lasers are also used for cutting, drilling etching and otherwise processing a wide variety of materials including metals and plastics. Lasers can be focused to very fine points allowing small holes or cuts to be made in nearly any material. Lasers are also used in medicine to remove tissue (laser eye surgery) and destroy tattoos or skin blemishes.
As mentioned above lasers can be used to precisely measure long distances by splitting the beam and bouncing one portion off a reflector on a distant target then comparing the phase of the returning beam to the reference beam. Interferometry is so successful that the definition of the fundamental distance unit, the meter, is given as wavelengths of light instead of he distance between scratches on a metal bar.
Lasers are used by the military to designate spots where a missile can home in to destroy a target or to help aim small arms using laser dot sights. Laser range finding is used to target tank fire as well. Several laser systems are being developed to shoot down missiles, mortar and artillery rounds and working prototypes of some systems exist. However as of 2010 there are no fielded laser weapons that use the laser beam itself to destroy a target.
Lasers are also key to information storage in the form of CD, DVD and Bluray technology. The ability to sharply focus the laser is used to read and write small dots on a spinning disc of plastic with metal foil layers.
Lasers are also used for performance and entertainment (laser pointers and laser light shows)
To summarize lasers are commonly used for communications, data storage, measurement, weapons targeting, machining operations, medical applications and entertainment.
How does hydraulic steering work?
Firstly you need reservoir for hydraulic oil from there goes one line to inlet port of hydraulic pump (which is driven by a engine or electric motor) then the high pressure port from hydraulic pump goes to hydraulic steering orbitrol, which is connected by a shaft to a steering wheel and has usually 4 ports. One port is connected to a pressure port from hydraulic pump (high pressure). Second port is return line to a reservoir (lower pressure). The other two ports are lines that goes to a hydraulic steering cylinder (which delivers the turning force to steering wheels).
Operation:
When the hydraulic pump is running and has pressure on outlet port the hydraulic oil flows through hydraulic steering orbitrol and back to reservoir. And when you apply turns to a steering wheel the hydraulic steering orbitrol redirects specific amount of hydraulic pressure to a hydraulic steering cylinder and there you have a turning force.
-_- max
