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Ah!! Theres not much like the thrill of seeing the latest Hollywood blockbuster on the big screen! Excitement fills the air as the house lights dim. The low murmur from the speakers begins to rise and surround you as the sounds permeate the theater from back to front, left to right- adding a bit of vibrating excitement from the tips of your toes up to top of your head. Every hair on your body stands up on end. This experience can be recreated in your very own home, as long as you have the right home theater equipment.

A DVD player is mandatory, as the output of such a device is over 500 horizontal lines of resolution compared to just 200 lines on a VHS tape for a VCR. Prices for these players can run from $30 to $250 or more depending on the amount of extra doodads you want to have. DVD players can also play the majority of music CDs, therefore alleviating the need for a separate system.

The television in most home theaters is one of the widescreen models, as the majority of DVDs are created in this particular format to imitate the theaters, but you can play DVDs on any type of screen. Most new televisions larger than 27 diagonally are made only as widescreen sets, including those in the three main types of sets sold for home theaters: flat-panel, rear-projection and front-projection in plasma, LCD (Liquid Crystal Display) and HDTV (High Definition Television).

Some useful information for picking out the perfect television: Flat-panel TVs come in nearly every size and run between $700 and $10,000; rear-projections are typically 42 and up to about 70, and will cost between $1,000 and $5,000. Front-projections with High Definition start at $1,500 and head upward, but require a very dark room for a decent picture. LCD is best for a light room, while Plasma TVs have darker darks and richer tones to create a better overall experience.

There are ideally 5 speakers in a home theater- a large one to place above or on top of the television, one smaller one to each side of the TV, and one at each rear corner of the room. Basically, the four smaller speakers should be in the corners of a square or rectangle that creates your home theater room. If you have high, slanted or cathedral ceilings, or arent thrilled with the idea of drilling holes to suspend the speakers from the ceiling, speaker stands will work just fine. If the stands are chosen properly, as well as the speakers, they can either stand out or blend nicely into your rooms d?cor. And dont forget the subwoofer to create the rumbling bass-sound for the echoes of explosions and/or the oncoming entourage of airplanes, as what would a home theater be without those./pbr
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Author: John Griesebr
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1.0 Introduction

The practice of anodizing, or controlled oxidation, of aluminum and aluminum alloys is more than seven decades old. The primary intent of anodizing aluminum and aluminum alloy parts is to protect the highly reactive surface against corrosion in aqueous environments, such as humid air and sea water. Because the anodic coating can be produced in a variety of colors, painted anodized parts are used in architectural applications. Furthermore, because the anodization process produces a hard ceramic coating, many times harder than that of the substrate from which it is formed, anodic coatings are also used to protect aluminum parts from abrasion, especially sand abrasion.

2.0 Traditional Anodizing

Traditional anodizing is an electrochemical oxidation process. The part to be anodized is connected to the positive terminal of a Direct Current (DC) power source and a nonreactive metal, such as stainless steel, is connected to the negative terminal. The aluminum part, or the anode, and the stainless steel cathode are immersed in an electrolytic bath and a DC voltage is applied across them. The potential difference is of the order of 20 -100 V and the current densities are 1-10 A/dm2.

The electrolytic baths comprise aqueous solutions of chromic acid, orthophosphoric acid, sulfuric acid, oxalic acid, or combinations thereof. Because the electrolytic baths have appreciable resistivity and because the anodization process itself is exothermic the temperature of the electrolytic bath increases greatly during anodizing.

Since the anodizing process is quite sensitive to temperature, the bath temperature is controlled rather closely by heat exchanger or refrigeration equipment. Todays advanced anodizing technologies include several proprietary hard anodizing processes that employ a wide range of electrolyte compositions, operating conditions and a limited aluminum alloy compositions.

The type and thickness of coating obtained greatly depends on the composition of the electrolytic bath, operating conditions and alloy compositions. The military specification MIL-A-8625F, for example, lists at least six types and two classes of electrolytically formed anodic coatings on aluminum and aluminum alloys for non architectural applications.

Despite the many decades of experience and the expensive equipment employed by the traditional anodizing plants, the acid bath based DC anodizing process has severe limitations.

? By the very nature of the low voltage DC power employed, the anodic coating is quite porous. Often the volume percent of pores is as much as 50%.
? Because of the low current densities employed, it takes many hours to produce a coating of a few tens of micrometers thick.
? The electrolytic baths comprise extremely low pH acidic electrolytes and thus the process does not meet many of todays environmental regulations. The expensive equipment, such as the electric power supplies and heat exchanger, makes the process capital intensive.
? The traditional process, for reasons not quite apparent, cannot be used for anodizing aluminum alloys containing high concentrations of Cu and Si.
? Thus, many aerospace and automotive parts cannot be satisfactorily anodized, if at all.
? The present process, while appropriate for a limited range of the wrought aluminum alloys, cannot be used for anodizing other reactive metals, such as Ti, Zr, Mg, etc., and intermetallic compounds and metal matrix composites. Thus, most of the promising aluminum based advanced alloys and composites cannot be protected by the traditional anodizing process.
? Above all, the hardness of even the so called hard anodic coatings is far below the hardness of alpha alumina, the principal component of the anodic coating. Accordingly, the full strength potential of the anodic layer cannot be realized by the traditional process.
? Indeed, the other potentially beneficial properties of aluminum oxide, such as the high thermal and electrical resistivities and the high dielectric breakdown strength are not even addressed.

This state of affairs is primarily due to the porosity of the coating produced by the traditional acid based electrolytic processes at low power levels, and to certain extent the poor bonding between the aluminum alloy substrate and the anodic layer.

3.0 The Microplasmic Process

In recent years, the Microplasmic Corporation, a start up RD company of Peabody, MA, U.S.A. has developed a unique anodizing technology, called the Microplasmic Process for all types of aluminum alloys. It is an electrochemical micro arc oxidation process for which a US patent is pending. A controlled high voltage AC power is applied to the aluminum part submerged in an electrolytic bath of proprietary composition. Due to the high voltage and high current, intense plasma is created by micro arcing at the specimen surface and this plasma in turn oxidizes the surface of the aluminum specimen. Thus the process is called Microplasmic Process. The oxide film is produced by subsurface oxidation and considerably thicker coatings can be produced.

Much as the traditional process, the Microplasmic process is an electrochemical process, but there ends the similarity. The Microplasmic process is radically different from the traditional anodizing processes in many respects. The distinguishing features of the process may be summarized as follows.

? The process employs alkaline electrolytes whose composition is extremely critical to the coating rate and the properties of the anodic film that is formed. The pH of the electrolyte is in the range 8 -12 and is thus environmentally sound.
? The process employs Alternating Currents at high voltage and high current. Because of the high voltage, a microplasma surrounds the electrodes and the oxygen ions produced in the plasma diffuse through the anodic film into the aluminum substrate to react and form more anodic film.
? The high voltage and high current allow the production of anodic films of the same thickness as that of the traditional process in a fraction of the time.
? Because the voltages are higher than the breakdown voltage of the film formed, open channels are not necessary for sustaining the process and hence dense thick layers of nonporous film can be readily formed.
? Because the process employs AC power, the productivity is increased.
? The power from an electrical utility supply can be used with proper controls to the electrochemical tank thus making the process less capital intensive. There is no need for power rectification and waveform smoothing.
? The temperature of the electrolytic bath need not be precisely maintained. Indeed, successful coatings can be obtained even if the temperature excursions are as much as 10-20 oC, further simplifying the process.
? The electrolytic composition itself is quite variable for different types of coatings.
? Because of the high density of the coating, practically there is no change in the dimension of the anodized part, and a completely finished part can be coated without major post processing finishing operations. The Microplasmic Process, however, produces an outer soft coating of about 15% that may be buffed off; the remaining inner layer, is an extremely hard ceramic layer.
? Above all, unlike with the traditional anodization process, aluminum alloy parts of any composition can be successfully anodized by the Microplasmic Process. Even more importantly, a variety of ceramic alloy coatings, such as Al2O3.SiO2, Al2O3.MgO, Al2O3..CaO etc. can only be produced by the Microplasmic Process.
? The Microplasmic Process is also suited for a hard coating inside surface of a part i.e. cylindrical, conical or spherical hollow parts. Many coating processes in the market, like CVD, PVD, IVD, PEPVD, Sputtering, Thermal Spraying etc. are unable to coat inside surface of a long part.

4.0 Applications

Because the microplasmic process produces a thick, well bonded ceramic coating on a variety of reactive light metal alloys, it can be used for a broad range of applications. The primary application could be the replacement of heavier metallic alloys or the more expensive composite materials required by the aerospace and automotive industries by light metals (e.g., Al, Ti, Mg, and their alloys) coated by the Microplasmic Process. Other applications can be divided into the following categories: Chemical, Mechanical, Thermal, Electrical and Electronics, and combinations of these.

? Chemical: The ceramic coating can resist both aqueous and moderately high temperature and is resistant to strong acids and bases. Thus it can be used in chemical, and food processing industries.
? Mechanical: The hardness of the film is over 1300 kg/mm2 and thus the film can be used to resist sliding, abrasive and erosive wear. In addition the friction coefficient is low and thus can be used in marginally lubricated systems.
? Thermal: The thermal conductivity of the anodic film is much less than of metals. Thus anodized parts can be used to maintain uniform distribution of temperature and resist thermal shock.
? Electrical and Electronic: The dielectric breakdown strength of the Microplasmic film is comparable to that of alpha Al2O3 and hence can be used as an insulating film on electrical and electronic components.

Additionally, the Microplasmic Process is also well suited for hard coating interior surfaces (such as those of hollow cylindrical and conical parts), recesses, blind holes, threaded sections, and so on.

Many coating processes in the market, such as Chemical Vapor Deposition (CVD), Physical Vapor Deposition (PVD), Plasma Enhanced Physical Vapor Deposition (PEPVD), Sputtering, Thermal Spraying, etc. are unable to coat the inside surface of a long part. Thus, where appropriate these expensive coating processes can be readily replaced by the Microplasmic Process.

Microplasmic Corporation

Contact Information:
Microplasmic Corporation
17 Esquire Drive
Peabody, MA, USA
Tel (978) 531-9145
Fax (978) 531-3671
Email: info@microplasmic.com
Company Website http://www.microplasmic.com/
Public Relations Website http://www.microarcanodizing.com/

ABOUT THE AUTHOR

Jerry Patel:
BS degree Mechanical Engineering – Fairleigh Dickinson University
MS degree Engineering Management – Northeastern University
Nannaji Saka, Ph.D:
BS – Mechanical Engineering – Andhra University in India
MS – Metallurgical Engineering – Indian Institute of Technology
PH.D – Materials Engineering from – Department of Materials Science and Engineering at
MIT.br
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Author: Jerry L. Patel and Nannaji Saka, Ph.D.br
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Televisions of the past worked because of a cathode ray picture tube. Plasma technology replaces those tubes with individual pixels that respond digitally. Each pixel contains three glass encased globes that contain the colors blue, green and red. Those individual pixels are what make the picture so beautifully clear. The reason they are called plasma TVs is because of the plasma gas that is also encased within those glass globes. Once the TV is turned on, then the electrical charge heats up the gas and continues to spark with the colors needed to intensify the brightness level desired. The image is presented as a bunch of dots that become invisible to the eye at a reasonable distance, thus creating the picture we see.

One of the biggest advantages of a plasma TV is its versatility. They can be mounted on virtually any wall in the house, including the ceiling. They are thin, not bulky, and can be hidden easily inside walls or entertainment centers when not being watched. Electronic companies produce plasma TVs in a wide range of styles and sizes as well. Sony televisions and Panasonic televisions can be as large as sixty inches which makes for a stunning movie watching experience. The larger plasma television sets are true 16X9 HDTV-capable and show the picture the way it was originally filmed.

Plasma TVs have some disadvantages that need to be considered when deciding on a new unit. They are very fragile and have to be handled with extreme care. Although thin, these TVs are very heavy and require special wall mounts that have to be placed correctly to avoid breakage. The plasma technology will degrade with time due to phosphor wear, and will show up in picture quality. Some plasma televisions come with video processors which can up-convert lower quality recorded shows into a higher resolution and better picture, but not all plasmas are equipped with this feature.

Samsung televisions regularly offer fifty-eight inch screens, video processing and HD grade quality. Sony televisions offer more of the same with different models, prices and quality. Panasonic televisions come to the table with exceptional customer service as well as many of the same features offered by Sony and Samsung.

So how do you decide which plasma television would suit you? Search online or go to a local electronics store and find the one that tickles your fancy. Searching online affords an easier way to do the research needed to choose the best model with the most functions that your wallet allows. Once you have decided, then test drive that model in a nearby store. You will be delighted.

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Author: Phil Martinsbr
Source: ezinearticles.com

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July 8, 2004 — Five Misconceptions About Plasma TVs

Despite a seemingly endless stream of consumer enthusiasm for those sleek, super-model-thin plasma television displays, some rumors stubbornly persist.

Since plasma technology is celebrating its 40th Anniversary this year, I figure its high time someone took a moment to set the record straight. Hopefully, by giving you the hard facts about plasma displays and dispelling some of the more pernicious half-truths and flat-out untruths about them, I will be doing my part to help keep the plasma rumor mill in check. At the very least, this will force the rumor mill to get a lot more creative.

Misconception #1: Plasma TVs need to have their plasma gases changed out every couple years.

Perhaps the only compelling thing about this idea is that it resonates with good auto maintenance know how. To many people, plasma displays are like cars: You know how to use them, but you dont know a whole lot about how they work. Which is surely how this Urban Legend gained its foothold in the popular imagination in the first place. It has certainly been utilized by any number of unscrupulous TV salespeople to push extended warranties on otherwise unknowing marks — people who have already spent $5000 on a new TV and would have no compunction about shelling out another $250 more, provided it will help safeguard their investment. While purchasing some additional insurance against mechanical defects might be worthwhile, especially when you are buying something this expensive, using scare tactics to ring up extended-warranty sales is unethical.

Not to mention bogus: The idea that the ionized gases inside plasma displays either (a) need to be replenished periodically or (b) can be refilled is patently untrue. You simply cannot change out these phosphors every 3,000 (viewing) miles. Nor would you want to, because this would require you to change its entire glass display element out. And most manufacturers will tell you that its cheaper to replace an entire plasma unit that it is to replace its screen alone.

Misconception #2: A high-definition (HD) plasma TV beats an enhanced-definition (ED) plasma TV any day.

Not true. I suspect this misconception has been perpetrated by manufacturers, who want to move more expensive (i.e., higher-resolution) product, and by retailers, who are repeating whatever the manufacturer tells them. True, HD plasma displays are more expensive than their ED counterparts. The reason is that increasing the resolution on a plasma screen means fitting more pixels on that screen, which common sense should tell you is a more expensive proposition. A simple eyeball test will tell you, though, that this is not necessarily money well spent. Just because a plasma monitor is labeled HD does not necessarily mean that it handles things like internal conversion, contrast ratios, and interpolation well — which are the very of things that ultimately make or break a picture in terms of its displayed quality. In most cases, the quality of the picture you get from a given plasma display (whether its ED or HD) actually depends on the quality of its make. A good ED plasma TV from a quality manufacturer will always outperform an HD plasma TV from a mediocre manufacturer.

The quality of your incoming video signal will also determine the quality of the picture you see. A standard video signal will look no better (and sometimes can actually look worse) on a HD plasma monitor versus an ED one. So, before you rush out and buy a high-definition plasma display, consider a few things:

What percentage of your total television viewing involves HD video signals?

Will you be using your plasma monitor to display computer graphics signals? If so, high definition plasma monitors will do much to enhance the detail of things like Excel spreadsheets.

Do you mostly watch video content that originates from DVD, cable, or satellite cable, i.e., content that ED plasma displays handle best?

Misconception #3: Plasma TVs only last 4 or 5 years. They are like shooting stars, brilliant but short-lived.

It is difficult to say for sure how long a given plasma TV will last, but one thing is certain: Plasmas can (and generally do) last a decade, sometimes longer. The useful lifetime of a plasma display is calculated according to the amount of time it takes for the monitor to appear half as bright as it did the day you bought it. Half-life denotes the point at which manufacturers consider the picture on a given set to have dimmed enough to make a noticeable difference in picture quality and possibly merit replacement. The stated half-life of most plasma displays is around 30,000 hours — thats 10 years worth of 8-hour viewing days!

Misconception #4: Owning a good plasma TV is cost-prohibitive — for now anyway.

This is really two misconceptions rolled into one. The first has to do with the pricing structure of plasma displays. We all remember, some of us too well, the days in the mid-90s when plasma TVs started at $10,000 and had virtually no price ceiling. Well, things have changed. The growing demand for plasma displays, coupled with advancements in production efficiency (yield rates), have conspired to bring plasma TV prices back down to earth. You can get larger, better performing plasma TVs for a fraction of the price you might have just a couple years ago. (Nowadays, you can buy a 42 EDTV Plasma for $2700.) This is partly because fully 9 sets in 10 come off the production line ready for sale, compared to just 5 in 10 in 1999 and fewer than 2 in 10 in the early 90s. Further suppressing prices is the fact that the defect rate of Japanese-made plasma TVs in the U.S. has fallen to less than 1% of the total product import.

Just because plasma TV prices have come down over the past few years, though, does not necessarily mean that this pricing freefall will continue well into the future. I forecast very moderate price decreases (as a percentage of total price and as total dollar savings amounts) going forward. Sure prices will continue to drop somewhat, but is it worth it to wait for 6 months or a year for the next $200 price roll back?

As of Spring 2004, plasma production levels were high, defect rates low less than 1 percent, and price reductions were still decreasing as a total percentage of product cost. Consumers can always expect to pay a premium for cutting-edge technology, just not such a steep one as before. I suspect 42 EDTV plasma TVs will bottom out at around $1500 – $2000 by 2006 or so.

In short, plasma display technology has never been more affordable — not to mention reliable — for the average consumer.

Misconception #5: Plasma TVs are plagued by problems with burn-in.

Burn-in, or image retention, is the result of a damaged pixel, whose phosphors have been prematurely aged and therefore glow less intensely than those of surrounding pixels. The reason is that the damaged pixel has developed a memory of the color information that was repeatedly fed to it, causing it to glow in a static manner for a sustained period of time. This phosphor color information can actually become seared into the plasma-screen glass, and, in the case of permanent image retention, it does. Once these phosphors are damaged, they cannot produce the same levels of light output as the other phosphors around them do. But pixels do not suffer burn-in singly. Burn-in occurs in the shape of a static image that linger on TV screens — things like network logos, computer icons, Internet browser frames, etc.

In the end, plasma TV burn-in is not an issue that should cause undue concern in the average user. With a modicum of caution, most plasma TVs will probably never have a problem with image retention. A viewer may experience temporary ghosting, but this is certainly not cause for alarm. In truth, carelessness — i.e., not paying attention to what your TV is displaying and for how long — is really the leading cause of permanent burn-in.

For more information, visit our website at http://www.plasmatvbuyingguide.com

or contact: corporate@plasmatvbuyingguide.com [corporate@plasmatvbuyingguide.combr
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Author: Anonymousbr
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Millions of television sets are sold each year. Consumers make the choice between plasma, CRT, LCD and other types of television technologies. They select the size to suit their needs as well; from a few inches to the theater like 103 inch screens. Selecting a television set involves thousands of choices. But what if consumers could select the size and type of screen that they wish and end up saving thousands of dollars over the life of the television in energy costs? Or what if that same consumer could also significantly reduce air pollution and greenhouse gas emissions while getting the television of their dreams? Consumers do have the option of adding one more choice during their television shopping experience that could end up saving them 1/3 on their energy costs and significantly improve the quality of air through the Energy Star program.
Energy Star has been around since the early 1990s. It is a joint program of the US Environmental Protection Agency and the US Department of Energy. The goal of the program is to assist consumers in saving money and to protect the environment through energy efficient products and practices. The program requires products with the Energy Star label to meet strict energy efficiency guidelines. The program covers computers, monitors, office equipment, heating cooling, major appliances, home electronics, lighting, new homes, and more. In 2005 alone, it is estimated that the program saved Americans at least $12 billion on their utility bills and eliminated potential greenhouse emissions equivalent to that created by 23 million cars.
As consumers go out shopping for their next television, they might want to consider a few facts. The EPA and Department of Energy estimate that if half of all US households replaced their current television with an Energy Star model, the change would be equivalent to shutting down one entire power plant. In fact, an Energy Star qualified television uses about 30% less energy than standard units. In addition, if every television sold this year was Energy Star qualified, it would mean 9 billion pounds less air pollution. Energy Star models can be found in the plasma, LCD, or CRT types of screens so the choice to select the energy efficient model should not restrict consumers at all.
Most major television manufacturers do offer Energy Star models; Samsung, Sony, Zenith, Philips, Sylvania, Panasonic, and Sharp are just a few of the major brands. For consumers who want to include energy efficiency in their decision making process, they can visit the following site to assist them in identifying television models that meet the Energy Star qualifications.

http://www.energystar.gov/index.cfm?fuseaction=find_a_product.showProductGrouppgw_code=TV

Christine Peppler shares information on home entertainment and home electronics products, including televisions, on her website at: http://www.homemedias.info.br
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Author: Christine Pepplerbr
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