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How Do Photovoltaic Cells Work?

Wednesday, March 10, 2010 at 05:02PM

By Jed C Jones, Ph. D.

Photovoltaic cells are the energy sources behind solar panels. Photovoltaic cells work by converting light energy, or photons, into electricity that humans can use. Single photovoltaic cells do not produce much power, but strung together in arrays they can produce significant amounts of electricity.

These cells work by the act of photons (light energy) knocking electrons into a higher energetic state and producing electricity. Solar cells can be used to produce direct current (DC), which can power a direct current lights or charge batteries. However, they can also be connected to inverters that convert the DC to AC energy. AC energy is used by power grids to power cities and towns.

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* GREEN SPECIAL FEATURE,

* SPECIAL TECHNOLOGY,

Alternative Energy,

Photovoltaic Cell |

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Monday

08Mar2010

A Warning to Families - Does Reverse Osmosis Remove Pharmaceuticals From Water?

Monday, March 8, 2010 at 12:51PM

By Daniel Steven Acker

Does reverse osmosis remove pharmaceuticals from water? That is one of the questions that you need to consider if you are thinking of purchasing an RO system for your home. It has been recently discovered that there are trace amounts of pharmaceuticals in water supply systems across both the U.S. and Canada, and these drugs provide a potential threat to our health and well being.

We have to first consider what an RO water filtration system is designed to accomplish, before we can answer the question does reverse osmosis remove pharmaceuticals from water. It is a system that completes the task of cleaning our water reasonably well, but that also has many shortcomings.

RO works by pushing highly pressurized water through a membrane filter, effectively removing all minerals and seeable particles. Anything with a molecular weight less than or equal to the weight of the water, is also allowed to slip through. Many of the pharmaceuticals in water supply reservoirs are diluted to the point where they would easily pass through.

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* SPECIAL PHARMACEUTICAL |

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Thursday

04Mar2010

Aircraft Rivets and Aerospace Fasteners

Thursday, March 4, 2010 at 10:20AM

By John Routledge

Aircraft rivets

The two major types of rivets used in aircraft are the common solid shank rivets, which must be driven using an air-driven gun and bucking bar; and special (blind) rivets, which are installed with special installation tools. Solid shank rivets are used widely during assembly and repair work. They are identified by the material of which they are made, the head type, size of shank, and temper condition.

The material used for the majority of solid shank rivets is aluminum alloy. The strength and temper conditions of aluminum alloy rivets are identified by digits and letters similar to those used to identify sheet stock. The 1100, 2017-T, 2024-T, 2117-T, and 5056 rivets are the six grades usually available. AN-type aircraft solid rivets can be identified by code markings on the rivet heads. A rivet made of 1100 material is designated as an "A" rivet, and has no head marking. The 2017-T alloy rivet is designated as a "D" rivet and has a raised teat on the head. Two dashes on a head indicate a 2024-T alloy designated as a "DD" rivet. The 2117-T rivet is designated as an "AD" rivet, and has a dimple on the head.

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* SPECIAL AEROSPACE,

Engineering,

Fasteners |

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Monday

01Mar2010

How Shaft Seals Are Used in Different Industries

Monday, March 1, 2010 at 02:26PM

By Andrew K Long

Shaft seals are made for just about every piece of machinery imaginable that has a spinning part of any kind. This seal is necessary to seal fluids, grease, oil mist or some other type of lubrication.

There are many applications for the seal. Agitators for moving water around in recycling plants all the way to the household washing machines use this type of seal in several of the machine parts. It can be made to fit any size shaft. This makes fuel handling safer, and fuel pumps possible.

Plain and simple, if it spins, there is a sure bet that somewhere in the mechanics of the design there this type of seal. The shaft seal is part of what makes a spinning shaft run smoothly and be held on the true as it spins.

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* SPECIAL MANUFACTURING,

Shaft Seals |

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Friday

26Feb2010

Sealed Right, Sealed Tight

Friday, February 26, 2010 at 04:22PM

Proper installation can reduce or even eliminate seal failures

As straightforward as seal installation procedures might appear to be, the smallest errors can lead to premature failures. This is particularly true in the field. The good news is that these failures can be dramatically reduced or even eliminated by following a few key steps.

The entire installation process should always begin with a careful inspection of a new seal’s lip to identify the signs of damage or irregularities that will lead to leaks. The lip needs to be free of any nicks or tears and should not be folded back on itself. If a garter spring exists, it will need to be located in the related groove to ensure consistent contact with the shaft.

The next step is to inspect the housing bore and shaft that will interface with the seal. The bore and shaft should be free from burrs and the grooves or scoring that may have been caused during operation when the old seal was in place. And the installation process will be further supported by the use of lead-in chamfers, the specific dimensions of which can be obtained from the supplier of the seal.

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* SPECIAL DESIGN,

Seals |

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Tuesday

23Feb2010

Stainless Steel Maintenance Tools - Reducing Industrial Or Laboratory Process Contamination Risks

Tuesday, February 23, 2010 at 01:02PM

By Alan Stamm

Executives in industries such as electronics, biotechnology, pharmaceuticals, food processing and other fields should recognize that general industrial carbon steel tools introduce unacceptable risk of contamination from iron oxide (rust) and chrome particles.

An ordinary screwdriver or wrench is likely to undermine elaborate steps ensuring sterility and environmental integrity for sensitive production operations. Using appropriate hand tools to install and maintain sterile processing line machinery is an essential element of current good manufacturing practice in critical areas. Mechanics using standard shop floor pliers to repair stainless steel production apparatus subvert standard operating procedures to assure quality control and regulatory compliance.

This report summarizes risks from introducing general-purpose tools into aseptic or clean room settings, and shows why professional-grade stainless steel maintenance tools are the accepted standard for industries that also include health care, semiconductors, chemicals, a

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* SPECIAL MANUFACTURING,

Maintenance, Repair & Operations,

Stainless Steel Tools |

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Tuesday

23Feb2010

Vendor-Client Relations - Winning Strategies

Tuesday, February 23, 2010 at 11:56AM

By Michael McCarty

It's not our fault; it's the vendor's fault! Sound familiar? After over 25 years in the Financial Services industry as a vendor and a contractor of vendor services, I have seen the best and worst of vendor relations. From this experience, I offer you a brief outline of practical strategies to create a win/win scenario with your vendors.

The best place to start on building a solid vendor relationship foundation is to know what you want to accomplish with your vendors and your vendor relationships. Define your approach to vendor relations clearly within your business organization through your strategic plan development. I cannot emphasize enough the importance of a thorough iterative strategic plan for your business organization that includes initiatives necessary to promote good vendor relations. Don't stop there! Cascade your strategic initiatives into ethical policies, procedures and practices throughout the organization so that you build a culture around good vendor relations. Make sure everyone knows, understands, and is committed to adopting and practicing the strategic concepts supporting good vendor relations. Consider using a documented positioning statement requiring attestation such as a Vendor Code, Vendor Affirmation, or Vendor Ethics publication.

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* SPECIAL OPINION,

Business,

Vendors |

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Monday

22Feb2010

Why O-Rings Fail

Monday, February 22, 2010 at 01:54PM

Perhaps the most famous, most catastrophic instance of o-ring failure in all of history was the failure at the launch of the space shuttle Challenger on January 28, 1986, which resulted in the destruction of the shuttle and the loss of the lives of the seven astronauts aboard. The cause of the disaster was determined to be the failure of an o-ring seal in the right solid rocket booster which caused a breach in the sealed joint, allowing pressurized hot gas from within the rocket motor to escape and impinge upon the external fuel tank. This led to the structural failure of the external fuel tank and caused the space craft to succumb to uncontrollable aerodynamic forces and disintegrate. Unusually cold pre-launch temperatures were to blame for the o-ring's loss of flexibility and contributed to the disaster.

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* SPECIAL DESIGN,

* SPECIAL TECHNOLOGY,

Components,

Engineering,

O-Rings |

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Monday

22Feb2010

Comparison of O-Ring Materials

Monday, February 22, 2010 at 01:03PM

By Ron Bargman

While selecting an O-ring for your application, a lot of importance should be placed on the material of the seal being used. Since a proper sealing action is highly dependent on the condition of your O-ring, it is important that an O-ring material be chosen to best suit the operating environment of your application. Some of the common materials used to make O-rings are nitrile rubber or Buna-N, Viton(r), silicone rubber, neoprene, and PTFE or Teflon(r).

Choosing an O-ring material is dependent on a number of different factors, but two of the most critical factors are the operating temperature range that O-rings are subjected to and the different chemicals they may be exposed to. Some additional factors that play a role in the selection of an O-ring material include resistance to tearing and abrasion, and sunlight or aging. Since most O-ring materials react differently to diverse environments as well as chemicals, each material has its own advantages and disadvantages.

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Monday

22Feb2010

Bombardier opens new aircraft maintenance facilities in the US, Europe

Monday, February 22, 2010 at 12:25PM

Bombardier Aerospace has added a third commercial aircraft service centre in the United States, in Macon, Georgia. The nearly 100,000 square foot facility will serve Atlantic Southeast Airlines (ASA) exclusively and will be capable of handling up to six aircraft at a time. ASA has a fleet of 150 Bombardier CRJ aircraft including CRJ100/200/700/900 models. The new facility will be equipped to perform C checks on the aircraft, the second heaviest maintenance check that aircraft undergo, performed every twelve to eighteen months or after a manufacturer-specified number of flying hours.

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* SPECIAL AEROSPACE,

Aircraft,

Bombardier,

Maintenance, Repair & Operations |

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