In today’s world, one can hardly escape the subject of fuel prices and fuel supply. For a number of different reasons people have turned from standard petroleum based fuel sources and looked for a reliable alternative-fuel. Biodiesel is one such fuel that experts and enthusiasts have embraced as not only their idea of a fuel of the future, but is also their choice for a fuel for today. But, what is Biodiesel?

Biodiesel is a fuel containing some of the same traits as conventional diesel fuel. Biodiesel is made from high quality vegetable oils through a manufacturing process that can be done on a large scale – such as a refinery, or on a small scale – such as a home Biodiesel kit. The primary use for Biodiesel right now is as a substitute for petroleum based diesel fuel.

In different parts of the world, different plants are used as the source for the vegetable oil that is made into Biodiesel. Theoretically, any vegetable grown can be broken down and turned into Biodiesel, but right now most Biodiesel producers use one primary crop as their source. In America, the primary crop grown for Biodiesel production is corn. Corn, being one of the more common crops grown in American, provides a readily available supply of vegetable matter for Biodiesel manufacturers. In much of Europe, rapeseed is used in the production of Biodiesel. And, in Southeast Asia the primary plant grown for the manufacture of Biodiesel is Soybeans. After going through the manufacturing process, there is little difference in the properties of Biodiesel made from one plant over another.

The process used to manufacture Biodiesel from pure vegetable oil is called ester interchange. In the process the vegetable oil is combined with a much smaller amount of Methanol. Methanol can be manufactured by the fermentation of starch or sugar and it can also be produced from natural gas. The vegetable oil and methanol are placed in a small quantity of an alkaline catalyst and it is in this process that the chemical makeup of the vegetable oil is altered. The result is a clean burning fuel with a viscosity (flow properties) approximating that of standard diesel fuel. During this process, approximately 90% of what is manufactured is Biodiesel fuel, while the remaining 10% is in the form of the glycerine that was broken down from the vegetable matter. This glycerine can also be used in other applications in the chemical industry, making the manufacture of Biodiesel practically waste-free.

The current uses for Biodiesel are mainly limited to that of being a cleaner burning replacement for petroleum based diesel fuel. Biodiesel can be both economically viable and highly efficient for most mobile applications. There will be some performance and usage differences between diesel and Biodiesel and they will vary from vehicle to vehicle as expected. It is possible for most modern diesel engines to burn standard Biodiesel. Currently, Biodiesel is also marketed as a Biodiese/Ethanol mix or a Biodiesel/Diesel mix.

Still a young industry by any measure, Biodiesel is on it’s way to becoming one of the brightest lights in the search for a viable alternative-fuel.

Author Bio
Mark Allen is a supporter of finding a viable alternative fuel source. Learn more at BiodieselPlans.info!

This is similar to what happens inside older refrigerators. Instead of water, though, the refrigerator uses chemicals to do the cooling.

There are two things that need to be known for refrigeration.

2. When you have two things that are different temperatures that touch or are near each other, the hotter surface cools and the colder surface warms up. This is a law of physics called the Second Law of Thermodynamics.

Old Refrigerators

If you look at the back or bottom of an older refrigerator, you’ll see a long thin tube that loops back and forth. This tube is connected to a pump, which is powered by an electric motor.

Inside the tube is Freon, a type of gas. Freon is the brand name of the gas. This gas, chemically is called Chloro-Flouro-Carbon or CFC. This gas was found to hurt the environment if it leaks from refrigerators. So now, other chemicals are used in a slightly different process (see next section below).

CFC starts out as a liquid. The pump pushes the CFC through a lot of coils in the freezer area. There the chemical turns to a vapor. When it does, it soaks up some of the heat that may be in the freezer compartment. As it does this, the coils get colder and the freezer begins to get colder.

In the regular part of your refrigerator, there are fewer coils and a larger space. So, less heat is soaked up by the coils and the CFC vapor.

The pump then sucks the CFC as a vapor and forces it through thinner pipes which are on the outside of the refrigerator. By compressing it, the CFC turns back into a liquid and heat is given off and is absorbed by the air around it. That’s why it might be a little warmer behind or under your refrigerator.

Once the CFC passes through the outside coils, the liquid is ready to go back through the freezer and refrigerator over and over.

Today’s Refrigerators

Modern refrigerators don’t use CFC. Instead they use ammonia gas. Ammonia gas turns into a liquid when it is cooled to -27 degrees Fahrenheit (-6.5 degrees Celsius).
A motor and compressor squeezes the ammonia gas. When it is compressed, a gas heats up as it is pressurized. When you pass the compressed gas through the coils on the back or bottom of a modern refrigerator, the hot ammonia gas can lose its heat to the air in the room.

Remember the law of thermodynamics.

As it cools, the ammonia gas can change into ammonia liquid because it is under a high pressure.

The ammonia liquid flows through what’s called an expansion valve, a tiny small hole that the liquid has to squeeze through. Between the valve and the compressor, there is a low-pressure area because the compressor is pulling the ammonia gas out of that side.
When the liquid ammonia hits a low pressure area it boils and changes into a gas. This is called vaporizing.

The coils then go through the freezer and regular part of the refrigerator where the colder ammonia in the coil pulls the heat out of the compartments. This makes the inside of the freezer and entire refrigerator cold.
The compressor sucks up the cold ammonia gas, and the gas goes back through the same process over and over.

How Does the Temperature Stay the Same Inside?

A device called a thermocouple (it’s basically a thermometer) can sense when the temperature in the refrigerator is as cold as you want it to be. When it reaches that temperature, the device shuts off the electricity to the compressor.

But the refrigerator is not completely sealed. There are places, like around the doors and where the pipes go through, that can leak a little bit.

So when the cold from inside the refrigerator starts to leak out and the heat leaks in, the thermocouple turns the compressor back on to cool the refrigerator off again.
That’s why you’ll hear your refrigerator compressor motor coming on, running for a little while and then turning itself off.

Today’s refrigerators, however, are very energy efficient. Ones sold today use about one-tenth the amount of electricity of ones that were built 20 years ago. So, if you have an old, old refrigerator, it’s better to buy a new one because you’ll save money (and energy) over a long period of time.

For more information go to:

• Argone National Laboratory – Ask A Scientist (http://newton.dep.anl.gov/newton/askasci/1993/eng/ENG30.HTM)

• Mr. Hand’s 8th Grade Science Site (www.mansfieldct.org/schools/mms/staff/hand/heatrefrig.htm)

• How Stuff Works – Refrigerator (www.howstuffworks.com/refrigerator.htm)
• Science Treasure Trove – refrigerator page (www.education.eth.net/acads/treasure_trove/refrigerator.htm)

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Many tv viewers are finding that cable service companies are lacking quite a bit, not only is the area covered unevenly but many cable companies do not supply an extensive array of programming. This is resulting in more viewers looking for other options, which gives more satisfying services as the cable tv service suppliers have only limited high definition scheduling to offer. This is because cable providers generally do not have the engineering necessary to deliver the HD tv (HDTV) programming in the higher quantities and variety that satellite tv providers are able to provide. Both Direct TV and Dish Network offer a variety of high definition programming that is quite appealing to tv fans.

In this regard the Dish Network has gained a lot of popularity with viewers since they are able to provide more than 30 channels of HD scheduling. The Direct TV has an HD package, which provides a huge number of channels, which is even more than what the cable television provides or any other provider. More numbers of high definition scheduling could be added by the viewer to the already present program packages offered by the satellite service providers. This can fit the budget of any television viewer as he can add high definition programming to any basic package, which is supplied to him at a very reasonable price. A large number of viewing options as well as umteen music channels are included in the standard package.

You also have access to a high definition audio engineering, which is part of the feature of HDTV programming provided by both the satellite suppliers. The digitalized surround sound is music to the ears since it uses the Dolby noise reduction facility and seems as if it is from a CD where every note is clear and sharp. Most viewers will find that the quality of sound provided by high definition scheduling is quite superior to the sound they are accustomed to hearing from their tv. To add more zing to their audio experience a lot of viewers hook up their tv to stereo speakers.

Additionally viewers can access a far greater picture quality when they take subscription packages from Dish Network or Direct TV HD. Many consumers do not realize that while the advantages of HDTV are frequently touted, it is difficult to take advantage of those benefits without programming in hd. The unique technology of HDTV allows viewers to see a picture that is far more defined and precise with hd scheduling. It is feasible for satellite TV to provide more channels than the cable companies since their hardware utilization has not yet hit its full capacity.

The recent sharp drop in the costs of HD televisions has made the sets more accessible to a larger customer base. Today customers are finding that you land up spending not very much more than a standard TV when you decide to buy a HDTV. Since there is an increase in the number of hd programs provided by satellite suppliers, we can expect a simultaneous rise in the customer base also who would enjoy this kind of superior quality programming.

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Michael Hehn is a specialist in HD TV. If you want more information about HD TV, visit HD TV info.