ZE-ENGINEER

Transducer

2012-02-02T18:53:00.001+02:00

A transducer is an electronic device that converts energy from one form to another. Common examples include microphones, loudspeakers, thermometers, position and pressure sensors, and antenna. Although not generally thought of as transducers, photocells, LEDs (light-emitting diodes), and even common light bulbs are transducers.

Transducers can be classified to two categories :

1- Input Transducers
Input Transducers convert a quantity to an electrical signal (voltage) or to resistance (which can be converted to voltage). Input transducers are also called sensors. Examples:

LDR converts brightness (of light) to resistance.
Thermistor converts temperature to resistance.
Microphone converts sound to voltage.
Variable resistor converts position (angle) to resistance.

2- Output Transducers
Output Transducers convert an electrical signal to another quantity.
Examples:

Lamp converts electricity to light.
LED converts electricity to light.
Loudspeaker converts electricity to sound.
Motor converts electricity to motion.
Heater converts electricity to heat.

DC Motors

2011-12-09T14:10:00.001+02:00

Recently I was working in a Solar Car design .

I had a problem in the designing of this solar car As my study is mechanical Engineering .

The problem was that the solar cells produce ( Direct current ) while all the motors i deal with work with ( Alternating current ) .This is related to ( Electrical Engineering Field )

After long day of search I found this file talking about motors work with Direct Current ( DC Motors )

I hope that i can help somebody faced the same problem . ^_^

HERE YOU ARE THE LINK AGAIN http://www.4shared.com/get/c7Q1RV20/Lecture_09_DC_Motor.html

future with robots

2011-09-24T21:12:00.001+02:00

Till now designers are unable to make a robot that can simulate the smooth movement of human ,but robot also has some features .Robot can work long time without rest or mistakes, can carry heavy things and can work in narrow space such as in nanotechnology. Now we are going to discuss the latest Developments of robots in some important fields in our everyday life .

Using Robots to Build Beautiful Structures

We will let the photos talk about how we can use robots to build fantastic structures :

Home-robots :

t's been a long time coming, but Intuitive Automata's Autom robotic weight loss coach is now up for pre-order on a dedicated "MyAutom" website. If you haven't been following the saga of Autom, it was first an MIT Media Lab robot with a significantly different look. Autom's developer at MIT, Cory Kidd, co-founded Intuitive Automata to help commercialize Autom based on the original MIT project, and it's starting to look like everything will be coming together within the next year. Not to get off topic or anything, but it's fantastic to see a research robot like this make the difficult jump into the consumer market. Congrats to Dr. Kidd!

Anyhow, back to the robot. We know that Autom is designed to be exceptionally interactive, crunching data on your health, diet, and exercise regimen and giving back friendly and constructive criticism. Studies have shown that people who use Autom stick with their diet and exercise routines for twice as long as people using more traditional weight loss methods. Don't ask me how, maybe it's something about those big blue eyes?

If this sounds good to you, you can be one of the very first people to have this friendly little robot helping you out every day with a deposit of $195. This is not the final price, however, it's just the pre-order deposit. The final price is the $195 deposit plus a balance of $670 when the robot ships, for a total of $865. This does seem a bit steep, although I'll admit to not being familiar with how much a typical weight loss program costs.

military-robots:

Textron's T-Ram is the Suicidal Mini-UAV You've Always Wanted

The U.S. Air Force has been looking for what they're calling a "Lethal Miniature Aerial Munition System" to be fielded with special ops units next year. If the name of the program doesn't explain it, the above pic should: they essentially want a mortar round with wings, a camera, and a little engine. In other words, a surveillance UAV that can suicidally attack targets on command.

There are several systems with this capability currently in the works, but the operational requirements and principles are all the same. LMAMS needs to weigh three kilos or less, including the vehicle and the launching system. It needs to be able to deploy and fire in under 30 seconds, reach an altitude of 100 meters, and acquire and track a human-sized target in a further 20 seconds. At that point, the drone can either dive at its target, landing within a one meter radius and exploding its small (but still quite lethal) warhead, or it can loiter for up to 30 minutes, sending back live video.

Now, this seems like a fairly dangerous little robot to have around, but before you get all worked up about killer robots and stuff, remember that these special ops units already have tools to deal with situations that the LMAMS is designed for: namely, blindly chucking dumb mortars and grenades at things, calling in air support, or putting themselves in harms way to get a better view of their target. All the LMAMS does is to reduce risk and collateral damage. Or at least, that's the idea, but whether it'll work in practice remains to be seen.

humanoids :

Dr. James Law, a researcher at the Department of Computer Science at Aberystwyth University, has had an absolutely fantastic idea: he's nominated the iCub robot to carry the Olympic Torch as part of the 2012 Olympic Games, which will be held in London (that's in England, folks) starting next summer.

Dr. Law is proposing that iCub be included in the torch-carrying relay in honor of the 100th anniversary of the birth of Alan Turing, one of the guys who arguably invented the computer and whose test for artificial intelligence robots are continually striving to pass. This is a great idea, but I think that iCub should be part of the torch relay on its own merits: it'll be a first for robots and great publicity for engineering education and all that. Or at least, it'll be great as long as iCub doesn't faceplant in a puddle and snuff the torch out.

The only problem with this idea is that the short-sighted and obviously outdated nomination rules specify that all nominees have to be at least 12 years of age, which would mean that iCub wouldn't technically qualify. On the upside, nowhere does it say that nominess have to be human, so maybe iCub has a shot at this after all.

Smallest electric motor ever

2011-09-24T15:49:00.001+02:00

For the first time, an electric motor has been made from a single molecule. At 1 nanometre long, that makes the organic compound the smallest electric motor ever.
Its creators plan to submit their design to Guinness World Records, but the teeny motor could also have practical applications, such as pushing fluid through narrow pipes in "lab-on-a-chip" devices.
Molecules have previously converted energy from light and chemical reactions into directed motion like rolling or flapping. Electricity has also set an oxygen molecule spinning randomly. But controlled, electrically-driven motion – necessary for a device to be classed as a motor – had not yet been observed in a single molecule.
To address this, E. Charles Sykes at Tufts University in Boston and colleagues turned to asymmetric butyl methyl sulphide, a sulphur atom with a chain of four carbons on one side and a lone carbon atom on the other. They anchored the molecule to a copper surface via the sulphur atom, producing a lopsided, horizontal "propeller" that is free to rotate about the vertical copper-sulphur bond

Record smashed

Above the molecule they placed a metal needle a few atoms wide at its tip. When they flowed a current from this tip, through the molecule, to the conductive copper below, the molecule converted the electrical energy into rotational energy. It bounced around in jittery hops about 50 times a second.

Because the propeller is asymmetrical, there are two ways it can be oriented with respect to the copper. In one orientation – but not the other – the molecule's hops were not random but slightly biased towards rotating clockwise, allowing the researchers to classify it as a motor.

It is not clear why the bias occurs but Sykes suspects that an inherent asymmetry in the tip of the metal needle could explain why it only occurs in one molecular orientation.

Friction fighter

If accepted by Guinness, the motor will be a record smasher. The current world-record holder for the smallest electric motor is a giant by comparison, composed of two 200-nanometre-long carbon nanotubes. Current running through these nanotubes pushes drops of molten metal from the outside of one tube to the other.

Sykes hopes to harness his tiny motor to fight the friction that slows fluid flow in nanosized tubes.

Kevin Kelly of Rice University in Houston, Texas, who was not involved in the work, points out that if electrical energy transfer behaves differently depending on the shape of the molecules, this could have implications for the design of molecule-scale electrical circuits, which could be used in tiny sensors or computer chips.

Journal reference: Nature Nanotechnology, DOI:

Fuel Cells ( Energy Source of the Future )

2011-09-23T21:09:00.001+02:00

According to many experts, we may soon find ourselves using fuel cells to generate electrical power for all sorts of devices we use every day. A fuel cell is a device that uses a source of fuel, such as hydrogen, and an oxidant to create electricity from an electrochemical process.

Much like the batteries that are found under the hoods of automobiles or in flashlights, a fuel cell converts chemical energy to electrical energy.

All fuel cells have the same basic configuration; an electrolyte and two electrodes. But there are different types of fuel cells, based mainly on what kind of electrolyte they use.

Many combinations of fuel and oxidant are also possible. The fuel could be diesel or methanol, while air, chlorine, or chlorine dioxide may serve as oxidants. Most fuel cells in use today, however, use hydrogen and oxygen as the chemicals.

Fuel cells have three main applications: transportation, portable uses, and stationary installations.

In the future, fuel cells could power our cars, with hydrogen replacing the petroleum fuel that is used in most vehicles today. Many vehicle manufacturers are actively researching and developing transportation fuel cell technologies.

Stationary fuel cells are the largest, most powerful fuel cells. They are designed to provide a clean, reliable source of on-site power to hospitals, banks, airports, military bases, schools, and homes.

Fuel cells can power almost any portable device or machine that uses batteries. Unlike a typical battery, which eventually goes dead, a fuel cell continues to produce energy as long as fuel and oxidant are supplied. Laptop computers, cellular phones, video recorders, and hearing aids could be powered by portable fuel cells.

Fuel cells have strong benefits over conventional combustion-based technologies currently used in many power plants and cars. They produce much smaller quantities of greenhouse gases and none of the air pollutants that create smog and cause health problems. If pure hydrogen is used as a fuel, fuel cells emit only heat and water as a byproduct. Hydrogen-powered fuel cells are also far more energy efficient than traditional combustion technologies.

The biggest hurdle for fuel cells today is cost. Fuel cells cannot yet compete economically with more traditional energy technologies, though rapid technical advances are being made. Although hydrogen is the most abundant element in the universe, it is difficult to store and distribute. Canisters of pure hydrogen are readily available from hydrogen producers, but as of now, you can't just fill up with hydrogen at a local gas station.

Many people do have access to natural gas or propane tanks at their houses, however, so it is likely that these fuels will be used to power future home fuel cells. Methanol, a liquid fuel, is easily transportable, like gasoline, and could be used in automobile fuel cells. However, also like gasoline, methanol produces polluting carbon dioxide.

Get more information here .. http://ze-engineer.blogspot.com/2011/02/dont-know-about-fuel-cell-technology.html

The 15 most significant cars of the 2011 Frankfurt motor show

2011-09-17T15:02:00.001+02:00

Over 100 new cars were unveiled at the 2011 Frankfurt motor show, but which are the most important? From production cars to concepts that will never be built, CAR's road test editor Ben Pulman, decides on the 15 most significant models premiered at the IAA...

1 – Land Rover DC100 concept

Chunky and funky, it’s Land Rover’s Evoque, the Defender urbanised, modernised and stylised for the 21st century. Range Rovers have become too ‘bling’, but the DC100 has the restrained elegance of the Disco 3 – we’ll ignore its bright yellow sister, the speedster-style DC100 Sport. It’s not a conventional, utilitarian take on the Defender for the traditional Landie customer, but bar the Army just how much of a market is there out there? The most profitable sales are to be found in market segments where you can charge premium prices, so don’t expect a wash-with-a-hose £15k rival for the Panda 4x4. Most importantly, the DC100 – and its Sport sister – confirm that Land Rover will replace the Defender (it’s about time really), and public reaction to these two will shape the new car due in 2015.

2 – Mercedes F125 concept

Not the best-looking Merc concept car of recent years, but ignore it at your peril. Mercedes’ F-branded concepts always offer a glimpse of the future before any other manufacturer, and the F125 (built to celebrate the company’s 125th anniversary) is more forward gazing than most – think two generations hence. The F125 boasts a hydrogen fuel cell, cutting edge lithium-sulphur batteries, a gargantuan 620-mile range, an eMatic all-wheel drive system, and a lightweight body built from the ground up to accommodate the specific requirements of a hydrogen-fuelled powertrain. It’s Mercedes going all-in on an H2 future.

3 – Volkswagen Up

It’s not an innovative rear-engined and rear-wheel drive supermini like the original concepts promised; in fact, looking at its conventional layout you’d be forgiven for just thinking it’s VW’s replacement for the Fox. Which it is. But the VW Group has put a lot of thought (and thus money) into this car, there’ll be Skoda and Seat versions too, and a gaggle of Up concepts at Frankfurt previewed potential GTI, EV and faux-4x4 versions. Hundreds of thousands of these things will be built, and with that badge to boot, Ford’s Ka and every other little city car out there should be worried. Simple, straightforward, and destined to be a success.

4 – Skoda MissionL concept

Understated and so easy to overlook – it’s just a Skoda, after all. But the MissionL – anyone else read it as Missoni? – will reach production (almost unchanged) in 2012, and it heralds Skoda’s entry into the hotly contested hatchback class, thus far ruled by the Focus and Golf. With VW parts bin backing, Skoda’s propensity to offer more space for less money, and a badge that those in the know now respect, it’s going to shake things up. And help double Skoda’s annual sales to 1.5m units by 2018.

5 – Porsche 911

No, not the new 911. We’ll admit the new 991 is significant (it’s cleaner, faster and better looking than its 997 predecessor, and will become a hybrid at some point in its life) but instead the now-defunct GT3 RS 4.0 is on my list thanks to a technicality – it made its motor show debut at Frankfurt. It marks the end of a 911 that first ushered in water-cooled engines as the 996 in 1997, and secured Porsche’s future thanks to sharing parts with the Boxster. In final 4.0-litre guise it’s quite possibly the greatest road-legal 911 ever built, and unless Porsche’s engineers can work miracles, it’s also the end of the line for the amazing, motorsport-derived ‘Mezger’ flat six. Goodbye to a great.

6 – Jaguar C-X16 concept

Not actually as good looking in the metal as you might expect but there the disappointment ends (and it’s not exactly ugly). An aluminium chassis means it’s light, a supercharged 375bhp V6 for the R version means it’s fast, and prices from around £55k mean it’ll take on top-end Boxsters and bottom-rung 911s. It'll probably halve the number of deposits Porsche takes for the new 911 during the Frankfurt show.

7 – Citroen DS5

Utterly, utterly gorgeous. Citroen had a fleet of these, all in white with black wheels, shuttling tired hacks between the vast halls of the IAA, and they looked sleek, and low, and lovely. And no, I didn’t get a lift in one so I can’t be accused of giving PSA any preferential treatment. We get behind the wheel next month, and while I’d hate to assume the steering will be light and lifeless and ultimately the drive will disappoint, I reckon the DS5 was the best-looking new car at the IAA this year. Seriously.

8 - Maserati Kubang concept

Terrible. I know Porsche has the Cayenne and will soon have the Cajun, I know both Bentley and Lamborghini are working on SUVs, I know that this is the future as expanding, emerging markets demand these profitable cars which niche luxury manufacturers would only ignore at their peril. If you were the CEO, could you forgo a 4x4 knowing it dooms your company to build just a few thousand sports car each year? Or would you give the green light, secure Maser’s future, and set about improving the GT cars everyone loves? Exactly. That was from the head, so now from the heart. It’s ugly (every Maserati should be beautiful) and looks too much like a Mazda CX-7, and because it’s really a Grand Cherokee, a Porsche Cayenne is going to run rings around it.

9 & 10 – BMW i3 and i8

Couldn’t decide between these two carbon BMWs so they’re both in. Come 2013 the i3 will be launched in both range-extender and full EV forms, a £30k-plus supermini that’ll see just how much we’re prepared to pay for a car that’s shorter than a Fiesta. A genuinely innovative idea.

And in 2014 the £125k i8 supercar arrives. Audi has the R8 and Merc the SLS, and BMW missed the boat, yet while both rivals prepare limited-run, limited-range EV versions, the i8 will sail merrily past thanks to its three-cylinder hybrid drivetrain. It really is the supercar of the future.

11 – Ford Evos concept

Ignore the butterfly doors, don’t bother trying to find out what the powertrain is – instead, just look at the Evos. It’s not a jaw-dropper, but it heralds the start of a design language to replace the Blue Oval’s exisiting Kinetic Design. Which means the Mondeo, the Mk4 Focus, the next Fiesta, and every other Ford product over at least the next decade will be stylistically influenced by this car.

12 – Lancia Flavia Cabrio

Only Ferrari and Alfa seem to be surviving unmolested within the Fiat Group. Maserati has the Grand Cherokee-based Kubang, Fiat is flogging a Dodge Journey (thankfully not in the UK) and what’s going on between Lancia and Chrysler is utterly horrible. Us Brits get the American brand, which sells the 300C and Voyager alongside the Ypsilon and Delta, but it’s a name we don’t really care about. Pity the Italians then (and the rest of mainland Europe), as Lancia is being forced to sell the Voyager, the 300C (as the new Thema), and worst of the lot, the Flavia Cabrio. It’s just a 200 Convertible. There’ll be a business case behind it, but how low can you go? Worst car of the show. Look away if you don't want to be depressed.

13 – Alfa Romeo 4C concept

Another car that’s snuck in on a technicality: the 4C actually first appeared at the 2011 Geneva motor, but it’s been to the paintshop prior to its trip to Frankfurt, which gives us an excuse to feature it again. It’s gorgeous, stunning enough to distract you from the Flavia sitting opposite, and it’ll look like this when production starts in 2012. And it’s got the underpinnings to back up the good looks: carbonfibre platform engineered by Dallara, turbocharged 200bhp-plus 1.7, six-speed dual-clutch gearbox, rear-wheel drive, adaptive dampers. Just a few thousand will be built each year but it’s a brilliant halo car for Alfa to have as it returns to the USA.

14 – Toyota FT-86 II

Another car that we’ve seen before, but for Frankfurt it got a big rear wing and some new orange paint. Hardly significant, but this is the car that the CAR office is most excited about for 2012. Rear-wheel drive chassis, manual gearbox, 2.0-litre flat-four engine (with a turbo for the fast version). An excellent set of ingredients for a cheap sports car. Engineering partners Subaru meanwhile, are pissing around showing off boring transparent-paneled concepts and missing out on all the publicity.

15 – Vauxhall Rake concept

The VW Nils or Audi’s duo of Urban concepts could have featured here, as the automotive world readies a flurry a tiny, sub-500kg commuter vehicles. But Vauxhall’s effort, the Rake, is designed to be as cheap as possible (the suits mentioned a €12k starting price) with no carbon and just a simple steel chassis. And they say this could quite easily be in production by 2015. It also offers more weather protection than Renault’s open-air Twizy. An intriguing glimpse into our motoring tomorrows.

SOURCE : carmagazine.co.uk

Amazon.com Widgets

Happy Engineer’s Day India

2011-09-15T19:21:00.000+02:00

In India, Engineer's day is celebrated on September 15. This day is celebrated in the honor of Sir M. Visvesvaraya (1861-1962), who was a notable Indian engineer, scholar, statesman and the Diwan of Mysore during 1912 to 1919. Internationally recognised for his genius in harnessing water resources, he was responsible for successful design and construction of several river dams, bridges and implementing irrigation and drinking water schemes all over India.

He served as the dewan of Mysore State and was considered to be the architect of the all-round development of Karnataka.

Among his most successful projects are the design and construction of the K.R. Sagar dam and its adjoining Brindavan Gardens, turn-around of the Bhadravati Iron and Steel Works, setting up of the Mysore Sandalwood Oil Factory and the founding of the Bank of Mysore.

K.R. Sagar dam :

Other countries :

Engineer's Day in Argentina is celebrated on June 15

Engineer's Day in Colombia is celebrated on August 17

Engineer's Day in Iran refers to 24 February every year

Engineer's Day in Mexico is celebrated on July 1

I’ve no Idea about if other countries have an engineer’s day .. Do you have ??

YAK 42 CRASH ( Full Report )

2011-09-12T16:29:00.001+02:00

The Yakovlev Yak-42 (NATO reporting name: Clobber) is a 100/120-seat three-engined mid-range passenger jet. It was designed as a replacement for several obsolete Aeroflot jets as a mid-range passenger jet. It was also the first airliner produced in the Soviet Union to be powered by modern high-bypass turbofan engines.

ABOUT ACCIDENT :

The Yak-42 that crashed near Yaroslavl taking 44 lives last week was in proper mechanical condition and the latest repairs were done to all requirements, the transport prosecution has ruled. Pilot error is the most likely cause of the tragic crash.

The last scheduled service of the plane was in August, during which the right engine was replaced and all other defects were reportedly eliminated. All these repairs were certified and correspond to requirements informed the transport prosecution.

The company that provided technical maintenance of the Yakovlev Yak-42 aircraft was inspected by experts from the Russian transport prosecution.

An investigation by the Interstate Aviation Committee also failed to find any irregularities in the aircraft’s condition and operation prior to the crash, a spokesperson for the regulator said on Monday.

“The preliminary analysis showed that the lifting weight was within the norm; the pre-start check of control channels by the crew revealed no errors…Flight recorders so far revealed no signs of commands which would indicate sudden failures,” the committee said.

As earlier investigation ruled out the possibility that low-quality fuel could have been a cause of the tragedy. Technical problems and pilot error were the likely reasons behind the Yakovlev Yak-42 plane crash.

While the technical problem theory appears less possible on Monday, the most likely cause of the tragedy remains pilot error.

“Pilots may not have accelerated enough and forced the engines too late. When the plane hit the homing beacon mast, there was no chance to bring the machine under control,” a source in law enforcement told Interfax new agency on Monday. “This version is seen as the most likely,” he added. Though no official comments have been released so far concerning this scenario.

The examination of the flight recorders is expected in the coming days after the tape has dried. The “black boxes” contain the recording of the tragic flight, confirmed in the Interstate Aviation Committee.

After one of the two survivors of the last Wednesday crash died in hospital from severe injuries on Monday, flight crew member Aleksandr Sizov remains the only witness. His condition is listed as serious but stable. He has been moved to the main ward.

The investigation will have a chance to obtain evidence from Sizov only after he recovers sufficiently to be able to talk. This may become crucial information for the experts investigating the plane crash.

Workers of Russia's Ministry of Emergency Situations inspecting the wreckage of the Yak-42 aircraft that crashed during take-off near the Tunoshna Airport, Yaroslavl Region. The plane was heading to Minsk with the Yaroslavl's ice hockey team Lokomotiv on board. (RIA Novosti/Grigory Sysoev)

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All you need to know before buying portable generator

2011-09-03T18:05:00.000+02:00

What is the portable generator ?

A portable generator is a gas or diesel-powered device which provides temporary electrical power. The engine turns a small turbine, which in turn creates usable electricity up to a certain level of wattage. Users can plug electrical appliance or tools directly into the generator's sockets, or the portable generator can be professionally wired into the sub-panel of a home.

Many construction teams use a portable generator to power tools and lights at a remote site. Sports officials may also bring in a portable generator to aid in night play or to run an electronic timer/scoreboard. Most commonly, residents and businesses left without power after a weather event will use a portable generator to keep vital appliances operating. A portable generator usually has enough power to keep a freezer, refrigerator, television and some lights working.

How Many Watts Do you NeedUse the charts below to determine your wattage requirements for a portable generator.

Generator Manufacturers

Caterpillar is one of the largest industrial equipment and generator manufacturing companies in the world.

Cummins is a international leader in diesel engine and power generateration equipment.

Detroit Diesel is a manufacturer of heavy-duty diesel engines for commercial trucks and diesel generators.

Generac produces industrial, commercial, and residential power generator sets, as well as automatic transfer switches, fuel tanks, and enclosures.

Honda develops a top selling line of portable home, recreational, and construction generator products.

John Deere produces industrial diesel engines that are used by generator manufacturing companies worldwide.

Kohler is worldwide manufacturer of on-site power systems, residential backup, mobile, and marine generators.

Briggs and Stratton provides portable and home generators.

Onan manufactures RV, marine, commercial, home standby, and portable power gensets.

SDMO is an international manufacturer of industrial diesel powered gensets.

Safety Precautions while using the generator
There are a few safety requirements that should be adhered to while using a portable generator:

To avoid carbon monoxide poisoning when using generators one should never run generators indoors, including garages, basements and sheds. Get some fresh air immediately if you start to feel dizzy or weak.
Generators pose a risk of shock and electrocution, if they are operated in wet conditions. It is advisable to operate the generator under an open, canopy-like structure on a dry surface where water cannot reach it or puddle or drain under it. One should operate with their dry hands.
For connecting appliances to the generator, use of heavy-duty extension cords that are specifically designed for outdoor use is recommended. The wattage rating for each cord should exceed the total wattage of all appliances connected to it. Extension cords that are long enough to allow the generator to be placed outdoors and far away from windows, doors and vents should be used. The entire length of each cord should be free of cuts or tears.
One should never store fuel for the generator inside the house. Flammable liquids should not be stored inside living areas rather it should be kept in properly labeled, non-glass safety containers. One should also not store the fuels near a fuel-burning appliance, such as a natural gas water heater in a garage. Gasoline spilled on hot engine parts can cause fire.

Ford Introduces Three New Light-Duty Engines for 2011 F-150 Pickup Trucks

2011-07-11T16:48:00.001+02:00

The best-selling half-ton truck in the country is getting an all-new engine lineup for 2011. Ford is replacing its legacy two-valve and three-valve 4.6-liter V-8 twins and the venerable three-valve 5.4-liter V-8 in the F-150 with technically advanced six- and eight-cylinder engines that Ford says will be the most fuel-efficient in the industry. The truck maker is also shifting exclusively to six-speed automatic transmissions for every powertrain.

Six-cylinder engines are the unloved stepchildren of the half-ton segment. These entry-level mills have significantly less power and are only marginally more fuel efficient than most available eight-cylinder engines, making them an unpopular choice to power a full-size truck.

Ford dropped its old 4.2-liter V-6 from the F-150 lineup after 2008 – offering only V-8 engines – because even its two-valve 4.6-liter V-8 with a four-speed automatic was less thirsty yet delivered more power.

But for 2011, V-6 is no longer a dirty word when it comes to full-size pickups.

Ford’s all-new Duratec 3.7-liter V-6 is the new base engine for the F-150. It’s rated at 300 horsepower and 275 pounds-feet of torque on regular unleaded fuel, though it will also burn E85 ethanol. It debuted earlier this year in the 2011 Ford Mustang, where it’s rated at 305 hp and 280 pounds-feet of torque. It’s also shared with the Ford Edge crossover.

Fleet owners are most likely to be its customers, looking for a low-cost capable pickup. Ford Ranger buyers are another potential target for the 3.7-liter V-6, when production of Ford’s compact pickup ends in 2011. Ford also says it will be the most fuel-efficient engine in the segment.

The dual-overhead-cam, all-aluminum, 60-degree V-6 is stuffed with technology. Starting with composite upper and lower intake manifolds to feed air to the engine, the engine’s heads have four valves per cylinder (two intake, two exhaust) that are combined with twin independent variable camshaft timing, or Ti-VCT in Ford speak. Ti-VCT varies valve actuation throughout the power band so there’s improved torque at the low end, cleaner emissions and better fuel economy throughout the rpm range. Bucket tappets that actuate the valves are low-friction and designed to boost mileage further.

The 3.7-liter V-6 also features a die-cast aluminum deep-sump oil pan that helps the engine go up to 10,000 miles between oil changes. The high use of aluminum throughout the engine saves weight and further improves fuel economy.

With all of this power, maximum trailer towing with the 3.7-liter V-6 is up to 6,100 pounds. That’s more than the maximum 5,760 pounds for today’s Ranger.

The 3.7-liter V-6 will be available for all cab configurations, up to a two-wheel-drive SuperCrew – the only V-6 full-size pickup with a crew cab.

Which F-150 Models Get It? XL, STX, XLT

Availability? Fourth quarter of 2010

3.5-liter EcoBoost V-6

Ford isn’t bringing back just one V-6 for 2011. It’s offering two. However, the second six-cylinder engine has about as much in common with the first as Jaws does with Flipper. And this is one six-cylinder with lots of teeth.

As originally announced in 2009, the 3.5-liter EcoBoost V-6 will be the first application of Ford’s gasoline direct-injection twin-turbo technology in a half-ton pickup. It’s Ford’s effort to shrink engine displacement for improved fuel economy while delivering tons of low-end power.

How much power? Ford is still coy, but we estimate the 3.5 will be about 400 hp and 400 pounds-feet of torque, enough to give it best-in-class towing and highway fuel economy. Ford says it will be able to pull up to 11,300 pounds, which is today’s maximum towing rating for the F-150. That’s amazing when you imagine its displacement is smaller than a pair of 2-liter bottles of Coke.

EcoBoost V-6 performance is said to be diesel-like, with peak torque coming on early in the power band and staying flat throughout the rev range.

The twin-turbo setup should also prove ideal for towing at altitude, where a naturally aspirated engine can have difficulty feeding air to its cylinders.

In the engine lineup, the 3.5-liter EcoBoost and 6.2-liter V-8 will occupy the top two slots. Ford hasn’t said how much it will cost. It may carry a premium over the 6.2.

Official fuel economy and power figures will be revealed during the State Fair of Texas in September. We’ll be there to bring you initial driving impressions, too.

Which F-150 Models Get It? All except for Harley-Davidson and SVT Raptor

Availability? First quarter of 2011

5.0-liter V-8

The 3.7-liter V-6 isn’t the only engine that the F-150 will share with the Mustang. It’s also getting the all-new 5.0-liter “Coyote” V-8.

The engine, which makes 360 hp (at 5,500 rpm) and 380 pounds-feet of torque (at 4,250 rpm), is positioned as the midrange engine choice for the F-150, below the 3.5-liter V-6 and conventional large-displacement 6.2-liter V-8.

Although the 5.0 produces more power than the outgoing 5.4-liter V-8, it won’t carry as high a tow rating. Its maximum will be only 9,800 pounds trailering, instead of 11,300 pounds. Peak torque has also moved up the rpm band, from a low 3,500 rpm in the 5.4-liter V-8.

“It’s positioned as an entry-level V-8,” said Mike Harrison, Ford V-8 engine programs manager. “It’s one step up from the 3.7-liter V-6. It’s really replacing the [discontinued 2010] three-valve 4.6-liter V-8.”

The F-150’s 5.0 benefits from some of the work done on the Mustang’s 5.0, which was engineered with the goal of being able to add a supercharger at a later date to boost performance, Harrison said.

“We put a forged crank and good rods in [the Mustang’s 412 hp, 390 pounds-feet 5.0 V-8],” Harrison said. “The head bolts are upsized. The main bearing bolts are upsized. That then lends itself for a very robust truck application.”

The 5.0 also uses Ti-VCT to continually optimize power and fuel economy during two cam timing schedules – one for performance and one for mileage. It’s also E85 ethanol capable, which gives it increased power figures (and lower fuel economy), though Ford won’t say by how much.

There are some physical changes, too. The exhaust headers for both engines are different from each other for extra durability in the F-150. Instead of the Mustang’s unique tubular stainless-steel exhaust headers, the F-150 uses thermally tougher conventional cast-iron exhaust manifolds that give it a small loss in low-speed torque and performance, which has to recovered to improve the driving experience and meet long-duration high temperature work demands – such as during cross-country towing. To do that, Harrison’s team shrank the duration of the intake cam duration from 260 degrees to 240 degrees, dropped the compression ratio from 11:1 to 10.5:1 and advanced spark timing for extra low-speed torque. The changes also help F-150 owners run their 5.0 V-8 with regular unleaded instead of super unleaded for optimal performance in the Mustang.

The F-150 5.0 also gets a heavy-duty oil cooler that's not shared with the Mustang.

Which F-150 Models Get It? All except Harley-Davidson and SVT Raptor

Availability? Fourth quarter of 2010

6.2-liter V-8

The single-overhead cam 6.2-liter V-8 that debuted in the 2010 Ford F-150 SVT Raptor is rated at a brawny 411 horsepower and 434 pounds-feet of torque. But compared to the other engines for 2011, it’s a bit of a throwback. It has two valves and two spark plugs per cylinder, a cast-iron engine block and aluminum cylinder heads. It also features a cast-iron crankshaft, forged steel connecting rods and cast-aluminum pistons. "Powered by Ford" is proudly embossed on the valve covers.

Since it only has a single cam per cylinder bank, instead of Ti-VCT, the 6.2 uses dual-equal variable cam timing, where the intake and exhaust valve opening and closings are phased at the same time.

We expect that in the next two to three years Ford will revise the 6.2 with new heads, four-valves per cylinder, direct injection and Ti-VCT for improved mileage and power.

For now, this engine is a brute force power lifter that’s rated to tow up to 11,300 pounds (depending on model), the same as the EcoBoost 3.5-liter V-6.

Which F-150 Models Get It? Harley-Davidson, SVT Raptor and Platinum and Lariat with Max Trailering Packages

Availability? Now

Six-Speed Automatic Transmission

Every engine for 2011 will be paired with the F-150’s existing 6R80 six-speed automatic transmission, but Ford has improved the gearbox as well, with features inherited from the 2011 F-Series Super Duty HD pickups.

Progressive Range Select allows a driver to reduce the number of available gears so it’s easier to tow up a grade and hold a specific top gear without worrying about the truck upshifting and getting bogged down in a higher gear.

There’s also a manual shift function, which lets a driver operate the truck like it had a manual transmission. The driver can shift whenever needed, as long as it doesn’t over-rev the engine.

The transmission also receives new ratios so it can operate with a lower final drive ratio for improved highway mileage – we’re waiting for the final ratios from Ford and word about rear axle changes – tow/haul mode has been re-calibrated for improved grade-shifting during descents and there’s also a new one-way clutch for smoother 1-2 and 2-1 shifts between the first two cogs.

source : www.pickuptrucks.com

Wind Tunnel Basic Types

2011-06-28T18:54:00.003+02:00

Open Circuit

The open circuit wind tunnel is the simplest and most affordable to build. In these tunnels air is expelled directly into the laboratory and typically reingested after circulating through the lab, though some tunnels utilize instead a compressed gas source. In addition to their low costs, open circuit tunnels are also advantageous because they have are relatively immune to temperature fluctuations and large disturbances in return flow, provided that the volume of the laboratory is much greater than that of the tunnel.

There are two basic types of open circuit tunnels, “suckdown” and “blower,” and the two are most easily differentiated by the location of the fan. Blower tunnels are the most flexible because the fan is at the inlet of the tunnel, so the test section can be easily interchanged or modified with seriously disrupting flow. These tunnels are so forgiving that exit diffusers can often be completely omitted to allow easier access to test samples and instruments, though the omission often results in a noticeable power loss. Suckdown tunnels are typically more susceptible to low frequency unsteadiness in the return flow than blowers, though some claims have been made that intake swirl is less problematic in these tunnels because it does not pass through the fan before entering the test section.

Closed Circuit

As the name implies, closed circuit tunnels (also called closed return) form a enclosed loop in which exhaust flow is directly returned to the tunnel inlet. These tunnels are usually larger and more difficult to build. They must be carefully designed in order to maximize uniformity in the return flow. These tunnels are powered by axial fan(s) upstream of the test section and sometime include multistage compressors, which are often necessary to create trans- and supersonic air speeds.

Closed circuit wind tunnel.

Fluid Dynamics

2011-06-28T18:23:00.003+02:00

Ideal/Real Fluid

An ideal fluid is a fluid that that experiences no viscous forces. This property of inviscid fluids allow them to flow along walls without an velocity decay due to skin friction, and also eliminates drag on adjacent lamina due to velocity gradients. This in turn means that ideal fluids do not form turbulent vortices as these flow past obstructions. Ideal fluids can be thought of as body of tiny frictionless particles, capable of supporting pressures at normal incidence but unaffected by shearing stresses. Ideal fluids are strictly a theoretical conception, but are sometime useful in modeling real-world situations where viscous forces can be neglected to a reasonable approximation.
Viscous fluids more commonly found in practical situation are called real fluids, and though their analysis is a great deal more complex due to the addition of viscous forces, they are use in a far broader range of applications.

Laminar/Turbulent Flow

Laminar flow is the movement of fluid in thin parallel layers who slide one over the other much like sheets of paper. Each layer experiences strong viscous forces from adjacent layers and these forces have a damping effect on disruptions in the flow so that flow downstream of an obstacle quickly returns to its undisturbed state. Turbulent flow is the highly random and chaotic flow that occurs at high Reynolds numbers characterized by the formation of eddies and vortices of various sizes. Unlike laminar flow, in which fluid behavior is determined primarily by viscous forces, flow behavior in turbulent flow is determined by inertial forces. Calculating fluid behavior in turbulent flow is often very difficult, as the Navier-Stokes equations that must be used are very complex. These equations relate the pressure, density, temperature and velocity of a fluid through the use of rate of stress and strain tensors, and the result is a set of five coupled differential equations (an additional equation of state is also needed in order to find a solution). In all but the simplest of cases, these equations are extremely difficult to solve analytically, and most solutions must be found through approximations and the use of high speed computers.

Fluid Viscosity

Viscosity is often defined as a measure of how resistive a fluid is to flow or deformation. Viscosity can be likened somewhat to friction experienced by solid objects, but unlike the frictional forces between solids, viscous forces are independent of pressure. Viscosity is ultimately caused by cohesive intermolecular forces, and can be expressed mathematically as the ratio of shearing stress on a fluid to its velocity gradient. Viscosity can be observed in a number of common liquids. For example, maple syrup has a higher viscosity than water and so flows more slowly. Gases also experience viscous forces and these forces increase as the temperature of the gas increases. This is due to the fact that as temperature increases, so does the kinetic energy of the molecules and so there is an increase in rate of intermolecular collisions. To a good approximation, the viscosity of a gas goes as the square root of its temperature.

Skin Friction Drag

Skin friction drag is the component of the total drag, also called parasitic or profile drag, experienced by a body in a fluid flow due directly to frictional forces between the fluid and the surface of the body. Assuming no boundary layer separation occurs, skin friction is the sole source of friction.

Reynolds Number

Osborne Reynolds first introduced the dimensionless constant that bears his name in his 1883, in a paper he published in the Philosophical Transactions of the Royal Society. The paper, “An Experimental Investigation Of The Circumstances Which Determine Whether Motion Of Water Shall Be Direct Or Sinuous And Of The Law Of Resistance In Parallel Channels”, detailed the findings of his experimental work. Using an apparatus that allowed his to inject a small stream of dye into fluid flowing through a glass tube and using a manometer to determine flow velocities, Reynolds noticed that at lower flow velocities, the stream of dye remained intact but at higher velocities the coherent stream began to diffuse. He also noted that the diffused dye could be reformed into a stream if the velocity was decreased. Reynolds found that there was a critical velocity, which he termed the upper critical velocity, at which the turbulent flow developed and a lower critical velocity at which turbulent flow became laminar. Velocities located between these two points were classified as lying in the transition region.

The Reynolds number itself is a dimensionless constant used to distinguish laminar from turbulent flow in a pipe or channel or sometime around an immersed object, with lower values corresponding to laminar flow and higher ones to turbulent flow. The Reynolds number is calculated using mean velocity, pipe diameter, density, and viscosity, and is valid for any fluid. The Reynolds number is also dependent upon the geometry of the pipe, as well as the roughness of the walls. Analysis of the Reynolds number using the dimensionless forms of the Navier Stokes equations reveals that the Reynolds number is really a ratio of inertial forces to vicious forces. As of yet, no successful analytic methods for determining Reynolds numbers have been developed due largely to the difficulty associated with predicting turbulent flow, and so Reynolds numbers for flow through pipes or around immersed objects must be determined experimentally.

Boundary Layers

Boundary layers are regions of fluid located immediately adjacent to an immersed object or wall in which flow velocities are governed by viscous forces. Drag forces and most of the heat exchange experienced by the object are due to fluid in this region. Boundary layers typically begin as a very thin region of laminar flow that thickens with increasing Reynolds numbers and then gradually transitions to a turbulent layer flowing over a viscous sublayer. Flow outside of the boundary layer is independent of Reynolds number criteria.

Aerospace Hydraulic System Description.

2011-03-15T19:21:00.006+02:00

The Axial Piston, Electrically Depressurized, Pressure Controlled, Variable

Displacement Hydraulic Pump Assemblies, Models PV3--240--10, PV3--240--10A,

PV3--240--10C, and PV3--240--10D are engine--driven, inline, pressure--compensated

type units. When employed in an hydraulic system, the pumps provide a low--pulsating

flow of fluid in varying volume and within a predetermined pressure range. The pumps

are capable of operating in either a normal operating pressure range or in a depressurized

range, depending on system demands (see Fig. 1).

The pumps consist of several major components which are enclosed within a mounting

flange, housing adapter block, and valve block and control subassembly.

Mounting flange (1, Fig. 2), located at the coupling shaft end of the pump, is an aluminum

alloy machined casting. Its function is to provide attachment of the pump to the aircraft

engine accessory drive pad. A portion of the hydraulic seal between pump and aircraft

engine is provided by a seal mating ring (2) and retainer (3) which are located in the

mounting flange. Machined recesses in the mounting flange are provided to accept drive

shaft bearing (4) and control spring (5).

Housing (6) contains the pumping mechanism components. These components are

cylinder block (7), nine piston and shoe subassemblies (8), yoke (9), and drive shaft (10).

The drive shaft is supported in the mounting flange by drive shaft bearing (4) and in the

adapter block (11) by roller bearing (12). The cylinder block (7) is coupled with the drive

shaft by internal and external splines. The pumping action is generated by the piston and

shoe subassemblies within the cylinder block and is dependent upon the displacement

angle of the yoke.

Yoke (9) is supported in the mounting flange and swivels through an arc of 0 to 1730’ on

two yoke pintle bearings (15). The angle of the yoke is controlled by controlled fluid

pressure acting on actuator piston (16). Control spring (5) moves the yoke to the

maximum angle (1730’)when outlet fluid pressure is less than previously adjusted value.

Shoe bearing plate (17) supports the piston and shoe subassemblies which are retained

in the yoke by hold--down plate (18), retainer (19), and screws (20).

Wafer plate (13), located between cylinder block (7) and adapter block (11), provides the

valving action to direct fluid flow to and away from the cylinder block.

Case relief valve (21) in the adapter block, permits case fluid to pass directly into the

pump inlet in the event of case pressure surge. In this manner, the housing is protected

from possible rupture.

Impeller (22) is coupled to the drive shaft by impeller key (23). Incorporation of the

impeller permits pump full flow operation with an inlet pressure as low as 5 psig (35 kPa,

absolute).

The valve block and inserts subassembly (24) includes the solenoid--operated

depressurizing valve (26), and outlet blocking valve (27). The inlet, outlet and case drain

ports are an integral part of the valve block and controls subassembly. The inlet and outlet

ports provide the connection between the hydraulic system and the pump. The case

drain port provides connection between the hydraulic system reservoir and the pump.

Four seepage drain ports are provided, three of which are normally plugged. Seepage

drain from the fourth shall not be returned to the hydraulic reservoir.

Adapter block (11) contains the pressure compensator valve (25), case relief valve (21),

and case fill and bleed valve (32). The pressure compensator valve (25) consists

principally of a spring--loaded pilot valve operating within a bushing and an adjusting

screw which controls the preload on the spring--loaded pilot valve. The preload

adjustment determines the system pressure at which the pump begins to reduce its

yoke angle of displacement. Auxiliary piston (28) and control valve (29) activate the pilot

valve when the solenoid--operated depressurizing valve (26) is energized. The case

fill and bleed valve (32) minimizes trapped air pockets in the pump casewhich could contribute

to dry starts.

1. Mounting Flange 2. Mating Ring

3. Retainer 4. Drive Shaft Bearing

5. Control Spring 6. Housing

7. Cylinder Block 8. Piston and Shoe Subassembly

9. Yoke 10. Drive Shaft

11. Adapter Block Subassembly

12. Roller Bearing 13. Wafer Plate

14. Spring 15. Pintle Bearings

16. Actuator Piston 17. Shoe Bearing Plate

18. Hold Down Plate 19. Retainer

20. Screws 21. Case Relief Valve

22. Impeller 23. Impeller Key

24. Valve Block and Inserts Subassembly

25. Pressure Compensator Valve

26. Depressurizing Valve

27. Outlet Blocking Valve

28. Auxiliary Piston 29. Control Valve

30. Shaft Seal 31. Coupling Shaft

32. Case Fill and Bleed Valve

_________________________________________

The solenoid--operated depressurizing valve (26) enables the pump to operate in the

normal pressure range or in the depressurized pressure range. The normal pressure

range is 3025 psi (20 857 kPa) and the depressurized pressure range is approximately

1200 psi (8 274 kPa). When the pump is operating as a depressurized unit, a fluid flow of

about 1.5 gpm (5.7 liters/min) is generated by the unit. This flow provides lubrication and

cooling for the pump components. This fluid returns to the reservoir via the case drain

port.

Outlet blocking valve (27) is used in conjunction with the solenoid--operated

depressurizing valve (26) to isolate the pump from the rest of the system during periods

of depressurization, or in event of system failure. The outlet blocking valve will close

when the solenoid--operated depressurizing valve is energized and pump internal

pressure is directed to the back side of the blocking valve piston. The blocking valve will

reopen only after the solenoid--operated depressurizing valve (26) is de--energized.

Shaft seal (30) and other packings prevent external leakage. Shaft seal (30) is located in

mounting flange (1). Coupling shaft (31) connects the pump drive shaft to the engine accessory

drive. The coupling shaft incorporates a shear section to protect the pump

against sudden overload and to protect the engine accessory drive in the event of pump

failure.

The pump identification plate, located on the housing, contains areas for the following

items: model, part numbers, serial number, pump displacement (cu.in/rev), maximum

drive speed (rpm), maximum operating pressure (psi) and an inspection stamp.

Adjacent to the identification plate is a fluid plate which identifies the pump hydraulic fluid

as BMS--3--11 (Alkyl Phosphate Ester Base). The instruction plate, also located on the

housing, alerts personnel that the unit shall be filled with hydraulic fluid before starting.

The rotation plate, located on the mounting flange, indicates that the pump shall be

driven in a clockwise direction, as viewed from the coupling shaft end of the pump.

Raise your hands, Mr / Robot You're under arrest !!!!!

2011-03-14T18:55:00.001+02:00

Humans have long dreamed about creating mechanical slaves that effortlessly carry out our daily tasks. Imagine being able to tell a robot to mow the lawn, or paint the fence, or entertain you, or drive you somewhere, or even teach you about something. Will this be a reality?

Now the question is . what is the definition of Robot ?

According to Savage (1999, p. 127) a robot is a device that is re-programmable and multi-functional.
To be a robot a device must also have some degree of autonomy (the ability to carry on tasks self-sufficiently).
Therefore, a dishwasher which carries out a single task cannot be classified as a robot. Similarly, a remote controlled vehicle has no autonomy so it also cannot be classed as a robot.
Scientists must overcome some persistent barriers if they are to create competent humanoid robots.
1- Speech synthesis: the ability to get a robotic device to communicate using language.
2- Voice recognition: the ability to get a robot to understand us. Two seconds of speech may contain as much as 100 000 bits of data so it is extremely challenging to create computers powerful enough to process this amount of data.
3- Vision: the ability to get a robot to react as humans do to the physical environment using sophisticated vision systems.
4- Movement: the ability to get a robot to move around in the physical environment as humans can.
In your opinion will our society need to create special laws governing robotic technologies?

Asimov's Laws of Robotics Laws 1-3 were published in I, Robot, 1950 Law 0 was added by Asimov later.

1. A robot may not injure a human being or, through inaction, allow a human being to come to harm.

2. A robot must obey the orders given to it by human beings, except where such orders would conflict with the First Law.

3. A robot must protect its own existence as long as such protection does not conflict with the First or Second Laws.

0. A robot may not injure humanity or, through inaction, allow humanity to come to harm.

watch Videos about the latest Robots released HERE

God of speed Shayton 2012

2011-03-12T20:56:00.002+02:00

"Shayton is a new God, the God of speed and performance. Faster than wind, more powerful than storm and as beautiful as if it was shaped by supernatural forces themselves."

Shayton actually means "falcon" in Sioux Indian, so we’re guessing that their first supercar - the Equilibrium - is set to take on the prey that is the other more successful supercars of Europe.

The Shayton Equilibrium looks the part of a predator with its aggressive lines and muscular stance. Its power is also something to be reckoned with as the Equilibrium is ready to attack with a V12 engine that shoots out 1084 hp. This isn’t your typical walk in the park; this is a 0-60mph sprint time of 2.9 seconds and a top speed of 250mph.

Yeah, it looks to be that good.

Exterior and Interior

View Full Album

The lead designer for the Shayton Equilibirum was Andrej Stanta who says that the function added to this particular piece of art is what makes it a masterpiece. The Equilibrium has a carbon titanium chassis which is then dressed up with muscular and aggressive lines that are cut by large side intakes. The shape of the body provides an elegantly macho look to the supercar while allowing for low air resistance. Carbon titanium wheels complete the look of the Shayton Equilibrium.

Inside this new animal is a sporty and elegant interior consisting of leather, alcantara, carbon fiber, brushed aluminum, Recaro seats, and Bosch electronics. The interior is dominated by a driver focused cockpit architecture which means that everything is set up to ensure a driver/owner ultimate driving experience when the Shayton Equilibrium is pushed to its limits.

Engine

Under the hood of the Equilibrium, we will find a V12 engine that can battle with the best at 1084 bhp and a peak torque of 930 Nm at 5000 rpm. With a total weight of 1200 kilos, the Shayton will deliver a power-to-weight ratio of 1.42 kg/hp. This allows the super car to sprint from 0 to 60 mph in 3.1 seconds and hit a top speed of 250 mph.

Prices

Pricing and availability is where things get a bit rocky for this predator as there will only be 20 units made available with a double-take type price of 1,000,000 euro, or $1,400,000 at the current exchange rates. That may be a little steep - scratch, unbelievably steep - for our wallets, but the supercar hasn’t even made it to production as of right now so we all have time to save up the cash if need be. The company is already accepting preorders for the Shayton Equlibrium so if you have the money and an optimistic view for production, then you better give Shayton a call fast.

Source :topspeed.com

2016 Land Rover Defender

2011-03-08T18:17:00.003+02:00

What do the Land Rover Defender and the Mercedes-Benz Geländewagen have in common? Answer: They date back to an era when passive safety and exhaust emissions were only vague terms instead of strict norms. Although various exemptions have helped to extend the life for these and other golden oldies, the grace period granted by the European Union ends for certain in 2015. Mercedes has no replacement in the pipeline for the G-class, but Land Rover is exploring ways to replace or overhaul the Defender in time for the 2016 model year -- and is even considering a departure from the traditional body-on-frame construction.

The good news for American Land Rover enthusiasts is that an updated Defender would likely return to our shores for the first time since 1996, when emissions regulations and low sales led to its discontinuation here. However, reengineering such a low volume vehicle -- annual production volume has dropped to 20,000 units, globally -- will be no easy task. With this constraint in mind, Land Rover is considering several options for the next Defender, which has the fitting internal designation "Project Icon."

The simplest route would be to update the Defender's current "T5" platform, which also underpins the Range Rover Sport. However, this body-on-frame platform weighs too much and is not sufficiently flexible in terms of track and wheelbase. In addition, it suffers from a strong off-road bias and doesn't support alternative powertrains.

The other extreme would be to tag the Defender on to the LR2 components set, which has been derived from such humble passenger cars as Ford Focus, Mondeo, and Kuga. The question is: can this DNA be stretched far enough to cover the extreme requirements a new Defender needs to meet?

Another option for Land Rover would be to find a strong partner could share development costs and production volumes, but at this point all the big names seem to be tied up elsewhere.

That leaves a forth option, which is simply for Land Rover to develop its own new architecture with partner Jaguar. This would likely include a premium, aluminum-intensive space frame for the next Jaguars as well as the next Range Rover and Range Rover Sport, as well as a more affordable steel architecture, which should spawn in a first step the all-new Defender. Such a Defender would appear in two versions: an indestructible, no-frills Land Rover for Costa Rican coffee farmers and a chic and trick Road Rover for the Malibu in-crowd. Eventually, this same architecture could find its way under the next LR2, along with other new models. Expect four-cylinder gas and diesel engines play an increasing role, in combination with electric motors.

Source : automobilemag.com

Lift and Drag

2011-03-07T17:16:00.002+02:00

Lift and drag are two of the four forces that act on an airplane in flight. The remaining forces include gravity and
thrust. Under normal operating conditions, lift is opposed by gravity (the total weight of the aircraft including
occupants, fuel, baggage, etc.). Drag is a force generated during the production of lift and when an object passes
through the atmosphere. The force of thrust is opposed by drag. There are various kinds of drag. Some of the
more well known forms of drag include induced drag, parasite drag, profile drag, and interference drag.1
The production of lift involves the dynamic reaction of air passing over specially-shaped surfaces known as
airfoils or wings. The shape of an airfoil is designed to generate the requisite amount of lift to support the weight of
the aircraft throughout a variety of flight parameters. Most airfoils have a pronounced camber or curved surface that
causes the mass of air flowing over the surface to accelerate in terms of velocity. As a consequence, the pressure
along the cambered surface is reduced. With a reduction of pressure on one side of the airfoil and near-ambient
pressure on the other, a pressure differential is established that acts on the surface area of the airfoil. The

magnitude of this force equals the amount of induced lift.
Another element in the production of lift is the downward deflection of air as it passes away from the airfoil. This
movement of air provides a Newton action/reaction component to the production of lift. The downward action of the
air provides an upward reaction to the wing. This lift is known as dynamic lift. The total lift of the airfoil is the
combination of induced and dynamic lift.
Several factors affect the quantities of lift and drag produced as the airfoil experiences relative wind. The shape
of the wing, the total surface area of the airfoil, the velocity of the flowing air mass (airspeed), and the angle at which
the air strikes the airfoil (angle of attack) are key factors in the generation of lift and drag. In this unit, several
examples demonstrating the shape of the airfoil, speed of flowing air mass, and angle of attack are presented.

Whirling Arm

Introduction of Areodynamics ( Bernoulli’s Principle )

Airplane control surfaces

HOW Airplane Fly ?

Whirling Arm

2011-03-07T16:49:00.002+02:00

The whirling arm first came into existence around 1746. It was used by Robins to study ballistic characteristics of
cannonballs and other projectiles. He perhaps was trying to understand why artillery shells would reach a maximum
distance in which no additional amount of gunpowder added meaningful length to the flight of the projectile. During
this investigation, Robins used a whirling arm device to gather data concerning the resistance encountered by
projectiles passing through the air. This force, known as drag, opposes the movement of articles through the
atmosphere. The relationship between the speed of an object and the quantity of drag is basically exponential,
when speed is doubled drag is squared.

Aviation pioneer, Sir George Cayley (1773-1857), was
perhaps the first person to use a whirling arm device for the
study of aeronautics. His work influenced the investigations
of other aviation researchers, including the Wright Brothers.
As illustrated in Figure 6, the whirling arm is mounted on a
vertical axis. Sample airfoils are attached to the extremity
of the whirling arm. A cord is wrapped around the vertical
axle and attached to a weight. As the weight is allowed to
fall, the unwinding action of the cord around the axle
imparts a rotating motion to the arm. Consequently, the
airfoil is subjected to a certain airspeed, or relative wind, as it sweeps through the air in a circular path.

Through the use of this instrument, Cayley collected
data relevant to the response of airfoils at varying angles of attack. His research with the whirling arm began in
1804. He discovered that an area of low pressure developed over the upper surface, or camber, of the wing as it

travels through the air. Cayley also determined that the center of pressure moved as the angle of attack changed.
The center of pressure is the location where the aerodynamic forces of a wing are concentrated. The angle of attack
is determined by the relationship of the direction of the relative wind and an imaginary line, known as the chord line.
The latter runs from the leading edge of an airfoil to the trailing edge. Leading and trailing edges refer to the front
and rear portions of an airfoil in terms of air flow. Cayley used the information gathered during his study to produce
successful gliders. His contributions to the science of aeronautics have earned him the title, Father of Aerial
Navigation.

Whirling Arm Activities

Whirling arm activities are informative and loads of fun. The author first encountered this demonstrator at
Minneapolis, MN under the instruction of Dr. Norm Poff. The author somewhat modified the wing-on-a-string device
by adding a frame to increase airspeed and simplify operation. The frame also assists in terms of maintaining

and changing angle of attack. A more elaborate version of the whirling arm includes an angle meter and airspeed
indicator.

changing angle of attack. A more elaborate version of the whirling arm includes an angle meter and airspeed
indicator.

Materials needed for this exercise include a sheet of paper, 2 segments of straw 2" (5 cm) in length (use a milk
shake size drinking straw), cellophane tape, a hole punch, 2 lengths of fishing line, and a frame. See the illustration
of “A Simple Whirling Arm” for information concerning the construction of the frame from PVC pipes. Fold the paper
in half along its longest axis. Locate and make holes in the folded sheet about ¾” to f” (1.9 cm to 2.22 cm) from
the creased-edge using the hole punch. Be certain to align the holes to correspond with the grooves cut into the
horizontal PVC members. If you are using a standard hand-held hole punch, make the holes as far in from the
folded edge as allowed by the punch so that the holes are near the wing’s center of pressure. Carefully pre-fit the
straws in their holes. This measure will be helpful during
final assembly. If you have trouble working the straw
segments through the paper, cut a slight angle or bevel at
one end of the straw and insert this end. Do not tear the
holes during this operation. Remove the straw segments.
Next, form the airfoil by sliding the upper half of the folded
sheet so that its free edge is shoved towards the folded
edge about ½". Vary the amount of camber (how much
curve the upper surface has) by trying different
measurements (e.g., ¼”, d”, ½”, ¾”, 1", etc.) to see the
relationship of camber on lift. Apply a couple pieces of
cellophane tape to the free edge of the upper surface so

that the paper retains its airfoil shape. Reinsert the straw segments through their holes in the upper and lower
surfaces of the wing. They should have a firm fit. If needed, wrap a little tape around the portions of the straw
segments that protrude from the wing to secure them in place. Thread the lengths of fishing line through the straws.
Assemble the frame by attaching a 90/ PVC elbow to each end of the vertical member (refer to Figure 7). You may
elect to use ½” PVC pipes for the frame when constructing it for use with small children. For older children and
adults, ¾” PVC is appropriate. When using the Whirling Arm with lower grade levels, it may be advantageous to limit
the height of the unit to two feet. Frames for older children and adults should be three feet tall.
Assemble the Whirling Arm by firmly pushing and twisting the elbows onto the vertical frame member to produce
a tight, friction fit between the parts. A friction fit is all that is required to hold the pieces together. Insert a 1-foot
segment of PVC in the remaining hole in each elbow. Ensure that the machined grooves are away from the elbow.

The grooves may be made on a table saw using a shallow cutting
depth to about ½ the wall thickness of the pipe. To make a clean cut
in PVC, install the saw blade backwards (so it rotates in the opposite
direction of rotation). As before, push and twist the segments into
the elbows to ascertain an adequate friction fit. Adjust the elbows by
twisting so that the 1-foot PVC segments are parallel along the same
plane. For right-handed units, place the frame of the whirling arm in
your right hand and extend the device away from your body. Install
the wing so that the leading edge (the folded edge) is facing forward.
The same technique should be used to construct left-handed
models, only hold the frame in your left hand and point the leading
edge so that it points forward. Attach the lines to the frame. The
fishing lines must be tightly stretched across the frame. If the lines
are loose, the wing will be hindered in its ability to freely travel up
and down the frame assembly. To obtain the slight amount of
tension needed to keep the fishing lines taut, adjust the length of the
lines or position the knots so that the vertical frame member is
gently bowed. Ensure that the lines run parallel to each other.
A more advanced whirling arm may be constructed to include
an angle meter and airspeed indicator. The design is similar to the
Simple Whirling Arm with the following differences. Instead of
making the frame in the shape of the letter “C,” the frame is

rectangular. To keep the fishing lines taut, rubber bands are used. The fishing line is attached to the lower
horizontal member at one end and a rubber band at the other end. The rubber bands are engaged in the grooves of
the upper horizontal member. It is important to ensure that the lines run parallel to each other to prevent binding. A
couple of screws are added to each vertical member to provide a method for attaching the angle meter using rubber
bands. By having attachment points on each vertical member, the angle meter may be quickly moved from one side
to the other to switch from a right-handed model to a left-handed model and vice-versa. See the associated
illustration. The angle meter may be used to more accurately measure the performance of wings based on angle of
attack.
The airspeed indicator is situated in the center of the upper horizontal member. A pitot-type arrangement is
used to power the indicator. The airspeed indicator may be pivoted between its two upper elbows to allow straight
passage of the inlet air at varying angles of attack. The transparent tube is equally incremented with different
colored rings. Inside the tube is the indicator. As the air enters the pitot opening, the indicator is lifted in proportion
to the airspeed. See the illustration entitled, “Airspeed Indicator.” The velocity of the wind is just below the white
ring.
To operate the whirling arm, hold the frame vertical in
the appropriate hand. Extend your arm fully from your body
to obtain the maximum airspeed. The wing should be free
to move up and down along its guidelines. Noting which
end constitutes the leading edge of your wing and holding
the frame straight out, rotate your body in the direction of
the leading edge (counter-clockwise for right-handed people
and clockwise for lefties). An alternative method for
generating the necessary relative wind for flight is to walk
briskly or run with the device. Observe that the wing travels
up the string as it produces sufficient lift. With a little
practice, the operator will be able to carefully control the
quantity of lift so that the wing maintains a certain height
during flight. To eliminate the effects of centrifugal force
during flight, walk briskly, or run, in a straight line with the
whirling arm.
To demonstrate the relationship between lift production
and airspeed, spin (pirouette) or run at faster and slower speeds. Try different angles of attack (angle made

between the airfoil and relative wind) by tilting the frame. Invert the wing and see how it responds in regard to
airspeed and angle of attack. If it is windy, try to make the wing fly by pointing its leading edge into the wind. The
airfoil responds like the wing of an airplane or rotor of a helicopter.
Lift Generated by the Whirling Arm
As operators become familiar with the flight characteristics of their airfoils and the operation of the whirling arm, they
may fly the wing and maintain a certain altitude (the wing rises a certain distance and remains in place). At this
point, the forces of lift and gravity are in balance. Stated another way, lift equals gravity when the altitude is
constant. Therefore, to determine the amount of lift, one needs to know the weight of the flying machine. As the
weight of the wing used in this demonstration varies with the type of paper used, the length of the straw segments,
and the quantity of tape attached to the wing, the weight of the unit should be measured and recorded before final
assembly, if such information is appropriate for the particular grade level. The author measured a sample wing and
found that it weighed 5 grams. Converting grams to pounds (multiply by 0.0022), the wing weighed 0.011 pounds.
Disregarding the relatively negligible amount of friction produced between the fishing line and the interior of the
straws, the amount of lift needed to suspend the airfoil at a constant altitude is basically equal to its weight.
Therefore, when the sample airfoil maintains its altitude, 0.011 pounds (5 grams) of lift are produced.

Introduction of Areodynamics ( Bernoulli’s Principle )

2011-03-02T21:04:00.004+02:00

Daniel Bernoulli (1700-1782) was a Swiss scientist who studied fluid flows. From his work emerged “Bernoulli’s
Principle.” This law states that for a steady flow of a fluid, the total energy (combination of kinetic energy from the
velocity of the flow, the potential energy from elevation and gravity, and the pressure energy exerted by the fluid)
remains constant along its flow route. Therefore, when velocity increases, the pressure energy of the fluid must
decrease to maintain a constant level of total energy. In simpler terms, as velocity increases, pressure decreases.
Bernoulli’s Principle is used throughout the aviation industry. From the production of lift to the workings of a
carburetor, the relationship between velocity and changes in pressure is paramount to the operation of aircraft.

Bernoulli on a Straw
Bernoulli’s Principle may be illustrated using a simple device
manufactured from common materials. To construct a Bernoulli on a
Straw demonstrator, a straw, segment of cellophane tape, and strip of
newspaper are needed. A milkshake straw works well. Milkshake
straws may be distinguished from common soda straws by their inside
diameters. The former use a larger inside diameter than the latter.

Place a strip of newspaper that approximately measures 1¼” (3.17 cm)
by 6" (15.24 cm) on a flat surface. Cut the tip of one end of the straw at a
45/ angle to provide a bevel. Center the beveled tip of the straw so that
the bevel is downward and around 1" (2.5 cm) from one end of the
newspaper. The remaining 5" (12.7 cm) of newspaper should be free of
the straw. Carefully attach the tip of the straw to the newspaper using
cellophane tape. Ensure that the tape runs perpendicular to the straw

and even with the tip of the straw without blocking the orifice. Lift the unit from the surface. The newspaper should
droop away from the tip of the straw.
To fly the newspaper, raise the device to your lips (be certain
that the newspaper is hanging beneath the straw) and blow through
the free end of the straw. Depending on relative positions of the
straw and the newspaper, the strip of paper should lift and become
parallel with the length of the straw. Blowing excessively hard may
produce a fluttering action. If necessary, begin the flight by blowing
hard and lessen the airflow to achieve a steady flight.
Another, and more telling, demonstration of Bernoulli’s Principle
is shown when raising the straw to a vertical position and blowing.
In this example, the strip of newspaper is shaped like an inverted letter “J.” By vigorously blowing through the straw,
a low pressure of significant magnitude is produced. Such a pressure causes the newspaper to lift until it is parallel
with the straw. At this point, the newspaper is vertical.

Place the unit in your mouth, walk forward, and blow through the straw until the paper rises. Try it again at a
faster speed. For a real challenge, run forward while trying to lift the paper. Two forces are working against the
lifting of the newspaper. First, drag is acting on the paper as it dangles from the end of the straw. The lifting force
must overcome this measure of drag. Also, as you move forward, some of the velocity of the accelerated air flow is
negated by the forward motion of the unit. This lessens the effect of the exhaled airflow

The force producing the action associated with this demonstrator is Bernoulli’s Principle and the pressure
differential created. The air that passes over the newspaper is traveling at an accelerated rate. This generates a
low pressure on that side of the newspaper. Because the other side of the paper has higher pressure, stationary air,
a pressure differential is produced. When the force acting across the surface of the newspaper is sufficient to lift the
paper, the newspaper moves in the direction of the low pressure.

Hot Wings

Another demonstration of Bernoulli’s Principle may be performed using simple wings, Mattel Hot Wheels, and a segment of track.
Construct the wings from a manila folder. After trimming off the folder’s tab, cut it in half so that
the cut is perpendicular to the folded end. Shove one side of the folder towards the folded end to give the wing its
shape. Staple the trailing edge of the wing so that it retains its airfoil shape. Glue the wing to the top of one of the cars.

Hot glue or epoxy work well for this purpose. Ensure that the cambered (curved) surface points towards the
front of the car.

Construct the second wing and attach it to the second
car ensuring that the cambered surface is towards the front of the car.
Place both cars on the track so that they are facing each other. Refer to
the figure showing the top view of the Hot Wings.

Space the cars apart to allow for forward movement of each car.
Generate a low pressure between the wings by blowing in between
them. You may either vigorously blow in between the two wings or use a
blow dryer. As the air is accelerated, an area of low pressure is
produced between the airfoils. A pressure differential is created between
the outboard surfaces of the wings where the air is stationary and the
inboard surfaces where the air is rapidly moving. When this pressure
differential is distributed across the area of the wing, enough force is
generated to propel the vehicles towards each other.

Where these cars
move in a horizontal direction, the force generated is similar to the lift
developed by a wing in flight or a rotor of a helicopter as it revolves in its
circular path. Examine the illustration depicting the action of the blow
dryer.

NASA's Discovery's Final mission - Launch 24 February 2011

2011-02-27T01:20:00.003+02:00

Discovery's final mission into Space, carrying the Leonardo Permanent Multipurpose Module, or PMM, to the International Space Station. The PMM has been loaded with supplies, experiments, equipment and a humanoid robot assistant for the station. The Humanoid Robotic Astronaut is called Robonaut 2 and is the first robot of its kind to fly into and work in space.

Discovery on its 39th mission has had more space flights than any other shuttle

NASA's Discovery's Final mission 24 February 2011 with a crew of six astronauts plus one humanoid named Robonaut 2

Nearly 200 people from 15 countries have visited the ISS - International Space Station but so far the orbiting station has only ever had human crew members – that is until now. Like something out of Star Trek - The Next Generation in which the humanoid and much loved 'Data' assisted Captian Picard in so many ways. NASA have now developed a real life 'Data' this one is named Robonaut 2. It is the frst humanoid robot ever to be deployed in space, and although its primary job for now is teaching engineers how dexterous robots behave in space, the hope is that through upgrades and advancements, it could one day venture outside the station to help spacewalkers make repairs or additions to the station or perform scientific work.

The humanoid Robonaut 2, going by the nicknamed R2 is currently packed inside the Leonardo Permanent Multipurpose Module, which is packed with other supplies and equipment for the station. It is likely to be several months before Robonaut 2 or R2 is unpacked, but once it is - it will initially be operated inside the Destiny laboratory for operational testing, but over time both its territory and its applications could expand. There are no plans to return R2 to Earth and is to become a permanent memeber of the Space Station crew.

Robonaut 2 was developed jointly by NASA and General Motors under a cooperative agreement to develop a robotic assistant that can work alongside humans, whether they are astronauts in space or workers at GM manufacturing plants on Earth, R2 has been designed to assist humans. It has been designed to be strong yet safe enough to work alongside humans combined with dexterous qualiteis. It far surpasses previous humanoid designs.

Space shuttle Discovery STS133 successfully launched Thursday afternoon '24 February 2011' and soared with a blazing trail of power and smoke as it headed skywards towards the International Space Station 'ISS' on its important mission. The launch came after a last-minute technical glitch with the Air Force's Eastern Range that left only four seconds in the launch window and a practical limit of two seconds because of draining requirements with the external fuel tank. "It was one more second than Mike Leinbach (shuttle launch director) needed to get the job done, so there was plenty of margin," said Mike Moses, chairman of the Mission Management Team. Still, he joked, "I could use a little less heart palpitations in the final seconds of the countdown." Leinbach said launch simulations have conditioned the team of controllers to handle the pressures of last-second "go" decisions without jeopardizing a mission. "This was one for the record books," Leinbach said. "It may have seemed a little rushed to people on the outside. It's a testament to the team that we have practiced for this."
It was a busy day in Space because the launch of the shuttle was not the only thing to happen during the day. Just as Discovery's tank finished being fueled, a cargo-carrying Automated Transfer Vehicle from the Eurpoean Space Agency docked to the station. The spacecraft, which carried no people, launched from South America last week on an Ariane V. Bll Gerstenmaier, NASA's associate administrator for Space Operations, said, "This is a pretty tremendous day in spaceflight for us. For us to be sitting here today with both of these events occurring as they did is pretty amazing."

On its Way - its final mission - shuttle Discovery STS133 - 24 February 2011

Discovery has flown to space more than any other shuttle craft and has carried more crew members to orbit. It was the first spacecraft to retrieve a satellite and bring it back to Earth, has visited two space stations and launched a telescope that has seen deeper in space and in time than ever before.

Discovery has spent 352 days in orbit, nearly a full year and has circled Earth 5,628 times. Travelling at 17,400 miles per hour, it has covered a distance of almost 143 million miles which equals 288 round trips to the moon or about one and a half trips to the sun. Discovery has carried more crew members -- 246 -- than any other space vehicle. Those have included the first female to ever pilot a spacecraft, the oldest person to fly in space, the first African-American to perform a spacewalk, the first cosmonaut to fly on an American spacecraft and the first sitting member of Congress to fly in space.

Discovery's final visit to the ISS - International Space Station will coincide with the 10-year anniversary of a permanent human presence aboard the outpost.

SOURCE

Don’t know about ( FUEL CELL ) technology until now??? Do it today.

2011-02-20T20:50:00.002+02:00

Around the world huge investments are being made in new energy technologies to meet growing demands for secure, low carbon energy supplies. Fuel cells powered by renewable biogas are beginning to provide electricity, heat and cooling around the clock. The US Government has launched their draft plan for the implementation of hydrogen and fuel cell technologies, which they envisage can address critical challenges in all energy sectors - commercial, residential, industrial and transportation.

In this topic we can not tell you everything about Fuel cell because it’s a huge field although it’s too simple and useful .

In this topic you can know the following:

1- Introduction to Fuel cell and how does it work .

2- Some videos about it ( cause it’s more active and easy to understand).

3- Some special sites of Fuel cell to be up to date with this field cause it grows up very quickly .

4- hmmmmm I’ll tell you about it at the end of the topic ^_^.

_______________________________________________________________

A fuel cell is a device that generates electricity by a chemical reaction. Every fuel cell has two electrodes, one positive and one negative, called, respectively, the anode and cathode. The reactions that produce electricity take place at the electrodes. Every fuel cell also has an electrolyte, which carries electrically charged particles from one electrode to the other, and a catalyst, which speeds the reactions at the electrodes. Hydrogen is the basic fuel, but fuel cells also require oxygen. One great appeal of fuel cells is that they generate electricity with very little pollution—much of the hydrogen and oxygen used in generating electricity ultimately combine to form a harmless byproduct, namely water.

One detail of terminology: a single fuel cell generates a tiny amount of direct current (DC) electricity. In practice, many fuel cells are usually assembled into a stack. Cell or stack, the principles are the same.

Polymer Electrolyte Membrane (PEM) fuel cells used in automobiles—also called Proton Exchange Membrane fuel cells—use hydrogen fuel and oxygen from the air to produce electricity. The diagram to the right shows how a PEM fuel cell works.

Most fuel cells designed for use in vehicles produce less than 1.16 volts of electricity—far from enough to power a vehicle. Therefore, multiple cells must be assembled into a fuel cell stack. The potential power generated by a fuel cell stack depends on the number and size of the individual fuel cells that comprise the stack and the surface area of the PEM.

______________________________________________________________

http://www.fuelcelltoday.com/
http://www.fueleconomy.gov/
http://fdfc2011.lepmi.grenoble-inp.fr/
http://www.fuelcellmarkets.com/
http://www.fuelcellenergy.com/

_____________________________________________________________

Don’t forget to search for technology called ( Bloom Box Energy )

it’s too simple and active .The following video can help ..>>>

Full Information about Centrifugal Compressor

2010-12-12T19:01:00.004+02:00

Most cooling systems, from residential air conditioners to large commercial and industrial chillers, employ the refrigeration process known as the vapor compression cycle. At the heart of the vapor compression cycle is the mechanical compressor. A compressor has two main functions: 1) to pump refrigerant through the cooling system and 2) to compress gaseous refrigerant in the system so that it can be condensed to liquid and absorb heat from the air or water that is being cooled or chilled .

There are many ways to compress a gas. As such, many different types of compressors have been invented over the years. Each type utilizes a specific and sometimes downright ingenious method to pressurize refrigerant vapor. The five types of compressors used in vapor compression systems are Reciprocating, Rotary, Centrifugal, Screw and Scroll.

We can classify compression process into to types :

(a) Compression by decreasing volume:-

Required pressure is developed by trapping a gas in a chamber, reducing the volume of the chamber and increasing the pressure of the gas by the ratio of initial chamber to the final volume.

(b) Compression by accelerating fluid :-

The second method of compressing gases is based on the conversion of kinetic energy into the potential energy. Accelerating fluid to a higher velocity and then decelerating it by changing its direction of flow transforms the accumulated energy into potential energy

We are going to talk about Centrifugal Compressor

Centrifugal Compressors
Centrifugal compressors use the rotating action of an impeller wheel to exert centrifugal force on refrigerant inside a round chamber (volute). Refrigerant is sucked into the impeller wheel through a large circular intake and flows between the impellers. The impellers force the refrigerant outward, exerting centrifugal force on the refrigerant. The refrigerant is pressurized as it is forced against the sides of the volute. Centrifugal compressors are well suited to compressing large volumes of refrigerant to relatively low pressures. The compressive force generated by an impeller wheel is small, so chillers that use centrifugal compressors usually employ more than one impeller wheel, arranged in series. Centrifugal compressors are desirable for their simple design and few moving parts.

Centrifugal compressor works on the principle of accelerating a gas to a high velocity and converting its KINETIC ENERGY (velocity) into POTENTIAL ENERGY (pressure) by decelerating the gas. The gas enters the eye of the impeller and is accelerated to the outward edge of the impeller as it rotates. It then enters a diffuser where its direction is changed, causing deceleration. This deceleration converts the KE into the PE, pressure. If the gas is to be further compressed, then a return chamber directs it from the diffuser to the eye of the next impeller in series. The gas enters a collector or volute when it is to leave the compression stage. It is discharged to the process through a discharge nozzle.

§ The centrifugal compressor has no connecting rods, pistons and valves; so the shaft bearings are the only points subject to wear. The compressor discharge pressure is a function of gas density, impeller diameter and design, and impeller speed. Centrifugal compressor impellers rotate very rapidly:

Low speed 3,600 RPM

Medium speed 9,000 RPM

High speed above 9,000 RPM

Power is supplied by an electric motor or steam turbine. Vapor enters the on the center of impeller around the shaft and is directed through the impeller blades. As the impeller accelerate the gas, by the kinetic energy of the impeller is converted to the kinetic of fast moving gas. As the gas enter the volute, it is compressed, and the kinetic energy is converted to the potential energy of compressed gas. The velocity of the gas leaving the impeller is extremely high.

In order to pass from the low pressure in impeller to the higher pressure of the diffuser, the refrigerant necessarily needs high velocity In absence of sufficient velocity, the refrigerant will stuck in the impeller and the compressor will stall (surge) .

Therefore one of the fundamental parameter of centrifugal compressor design is the “tip speed ‘

Which must be in the range of 240 to 231 m/sec. This parameter determines the speed and the dimension of the impeller:

RPM=[TipSpeed(m/s)*1910]/ Diameter(cm.)

A centrifugal compressor must be specifically designed for the right pressure difference we want to achieve.

Part load conditions are the most critical for centrifugal compressors

Gas speed is even more critical in unloaded condition, when the gas flow decreases and therefore could not be able to overpass differential pressure to the diffuser. If this happens, the flow can go back into the impeller bringing compressor to stall .

One of the most innovative technologies which allows to keep sufficient gas speed also in strongly unloaded conditions and extends unit working range, is the movable impeller discharge technology.

Based on the type of casing design,centrifugal compressors are classified into two types:

1) Horizontally split casing design(MCL/MCH type):- This design is used for low working pressure below 40ata.These casings are in two halves with horizontal parting plane.DMCL Compressor have two stages of compression in parallel in a single casing.The solution is most balanced.The other aspects of construction are the same as for the MCL Compressor.

2) Verically Split Casing design (BCL/BCH type):-This design is made of barrel construction closed on the sides by end covers with help of studs.This type of construction is suitable for high pressure operations up to 750kg/cm2. Another type of compressor is the PCL(Pipeline compressor),which has casing in the form of a cup with a single closing flange in the vertical plane instead of two as with the BCL.

Example of Designation of BCL Compressor:

Example : 2 BCL 40 7 / b

2 BCL 40 7 / b

Compressor Components

§ Casing

§ Counter Casing (If Applicable)

§ Diaphragm

§ End Cover (If Applicable)

§ Shaft

§ Impellers

§ Shaft Seals

§ Journal Bearing

§ Thrust Bearing

§ Coupling

COMPONENETS OF BCL COMPRESSOR

Construction of centrifugal compressor:

§ Every centrifugal compressor consist of two parts:- An impeller which forces the gas into the rotary motion by the action of blades, and the casing which directs the gas to the eye of the impeller and then leads it away from the impeller perimeter at a higher pressure. For most multistage compressors, shaft end seals are located inboard of the bearings. The internal passages are formed by a set of diaphragms.

BARREL PULLING ARRANGEMENT

Rotor Assembly

Assembly of Diaphragms in Counter Casing

Assembly of Journal Bearing

BALANCING DRUM

There exists some amount of thrust generated at each impeller because of the differential pressure prevailing across it. The cumulative thrust generated across all the impellers is huge and it needs to be supported by the thrust bearing. The thrust bearing size becomes huge if all the gas thrust has to act on the bearing. For this purpose a rotating element called “Balancing Drum” is incorporated on the rotor. The drum is acted upon by a pressure differential which pushes the rotor in a direction opposite to that of the gas thrust. The thrust so generated balances the thrust produced by the impellers. Amount of balancing depends upon the size of the drum and pressure differential created across it. The pressure differentiated is maintained by an efficient seal placed over the balancing drum.

Cross-section of a BCL Compressor

Amazon.com Widgets

Casification of the compressors

2010-12-10T07:02:00.002+02:00

We can classify compression process into to types :

(a) Compression by decreasing volume:-

Required pressure is developed by trapping a gas in a chamber, reducing the volume of the chamber and increasing the pressure of the gas by the ratio of initial chamber to the final volume.

(b) Compression by accelerating fluid :-

The second method of compressing gases is based on the conversion of kinetic energy into the potential energy. Accelerating fluid to a higher velocity and then decelerating it by changing its direction of flow transforms the accumulated energy into potential energy

Refrigeration and Air Conditioning

2010-10-27T19:02:00.002+02:00

This topic isn't like any other one on this blog .Cause what we want to say this time can't be written on one or two internet pages.

We will put Modern Refrigeration and Air Conditioning referance on your hands

We hope that this book can help you if your work or study is related to Refrigeration and Air Conditioning

this book is a ( pdf ) file it's size is about 457 MB

ً We have devided the file into 5 parts

Every part is about 95 MB

Here you are the download links

1st part

2nd part

3rd part

4th part

5th part

And here you are some related vedios

Rotary Screw Compressors - Air System Fundamentals

The Compressor

The Refrigerant Circuit

Sand casting

2010-08-17T09:49:00.005+02:00

Expendable mold casting is a generic classification that includes sand, plastic, shell, plaster, and investment (lost-wax technique) moldings. This method of mold casting involves the use of temporary, non-reusable molds.

Sand casting

Sand casting is one of the most popular and simplest types of casting that has been used for centuries. Sand casting allows for smaller batches to be made compared to permanent mold casting and at a very reasonable cost. Not only does this method allow manufacturers to create products at a low cost, but there are other benefits to sand casting, such as very small size operations. From castings that fit in the palm of your hand to train beds (one casting can create the entire bed for one rail car), it can all be done with sand casting. Sand casting also allows most metals to be cast depending on the type of sand used for the molds.[28] Sand casting requires a lead time of days for production at high output rates (1–20 pieces/hr-mold) and is unsurpassed for large-part production. Green (moist) sand has almost no part weight limit, whereas dry sand has a practical part mass limit of 2,300–2,700 kg (5,100–6,000 lb). Minimum part weight ranges from 0.075–0.1 kg (0.17–0.22 lb). The sand is bonded together using clays, chemical binders, or polymerized oils (such as motor oil). Sand can be recycled many times in most operations and requires little maintenance.

Typical Cross-Section of a Two-Part Sand Casting Mold

The above diagram represents the most basic casting process used today. This process is used worldwide regardless of metal, alloy or molten liquid material being cast. Man used this concept at the beginning before Biblical times to
manufacture objects for decoration, weapons, utensils and hardware. This process is commonly known as sand casting
since sand, which is held together with a binder, is the medium to form the mold cavity.
Definitions
Core: A sand shaped insert placed in the mold cavity to produce internal features on the part.
Cope: The upper half of the sand mold.
Drag: The lower half of the sand mold.
Flask: A box made of wood or metal to contain the sand.
Gates: Multiple openings in the mold to allow the molten brass to flow into the mold cavity.
Gating System:
A passage where the molten brass flows into the mold. The gating system is made up of the pouring
cup, sprue, runner and gates.
Mold: A cavity or matrix by which molten brass is shaped into a desired product.
Parting Line: The line where the top and bottom halves of the sand mold meet.
Pattern: A representation of the final product used to imprint the shape into the sand.
Risers:
Reservoirs called risers inside the mold, which is filled with the molten brass to compensate for shrinkage or
"feed" the mold cavity during the solidification process.
Runner: The horizontal part of the gating system, which supplies molten brass to the gates.
Sprue:
The vertical part of the gating system, which is connected to the pouring cup at the top and feeds the runner with molten brass at the bottom.
Vent: An opening in the mold to allow the escape of hot gases.
Simple Casting Process Description
The flask is comprised of a bottom and a top half and together, they form the flask assembly. The upper section of the flask assembly is known as the cope and the lower section is termed the drag. The first step in the casting process is the mold must first be made. The drag or bottom half of the flask is filled with sand, which is pre-mixed with a binding agent to keep it intact. Inside the drag, there is a pattern, which will create the impression that will form the mold cavity (the patterns for the
top and bottom may be different depending on the object that is to be cast). The sand is compacted around the pattern by manual and mechanical means to ensure all the air is removed and that a smooth mold cavity is formed around the pattern. This procedure is repeated with the cope or upper half of the flask. Depending on the complexity and size of the part and the number of castings being made at one time, the pouring cup, sprue, runners, risers and gates will also be imprinted onto the sand or an expendable core will be used that will burn away. Once the sand has set, the cope and drag are flipped to remove the pattern thus leaving a void in the sand. Cores may be added, if necessary to create hollow and internal features on the final product. The next step is to close the mold and lock it in place using weights or clamps to keep the mold from splitting open at the parting line during the pouring process.
Now that the mold is complete, the molten brass is poured into the mold cavity via the pouring cup or hole. Once filled, the entire assembly is allowed to cool and solidify. Depending on the size of the casting, cooling time can take several hours
(in industry, some castings take over a week to solidify!). Once the molten brass has solidified, the flask assembly is taken apart. The sand mold is then broken apart to expose the product by hand tools, vibration, rotary drums or a combination of these techniques. At this point, the gating system is also removed, and the cores are disposed of.
Once the product is cool to the touch, they go through a rigorous cleaning and finishing process. The parting line on the casting is blended and any spikes or splinters are removed by mechanical means. Once the rough finishing is complete,
the parts are polished to a smooth finish in various grinding and buffing stages. Depending on the colour (natural brass, verdigris or black) the products go through a final finishing process to give it the desired colour. Once complete, the final products are ready for shipment around the globe.