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TODAY IN HISTORY

    URANIUM FISSION
    January 22, 1939 - Columbia University in New York City, U.S.A.

    The uranium atom was split for the first time using the cyclotron at Columbia University in New York City. Thus began the Manhattan Project, leading to the construction of the atom bomb. The project was subsequently moved inland to the University of Chicago to protect the research from any possible German bombing of New York. (Also the weight of the apparatus was so great that the floor was in danger of collapsing!) The cyclotron that performed the first-ever fission experiment was designed and built (1935-36) by John R. Dunning, who became Dean of the Engineering School, 1950-69). In 1965, the cyclotron was taken to the Smithsonian Institute. The original invention of the first cyclotron was by physicist Ernest Lawrence.

    SPACE DEBRIS HITS PERSON ON EARTH
    January 22, 1997 - Tulsa, Oklahoma, U.S.A.

    American Lottie Williams was reportedly the first human to be struck by a remnant of a space vehicle after re-entering the earth's atmosphere. At 3 a.m., while walking in a park in Tulsa, Oklahoma, she saw a light pass over her head. “It looked like a meteor,” she said. Minutes later, she was hit on the shoulder by a six-inch piece of blackened metallic material. The debris that struck Ms. Williams has not been examined to confirm its origin, but a used Delta II rocket, launched nine months earlier, had crashed into the Earth's atmosphere half an hour earlier. NASA scientists believe that Williams was hit by a part of it, making her the only person in the world known to have been hit by man-made space debris.

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  • No Man is Above the Law
    by Theodore Roosevelt

    "..."No man is above the law and no man is below it; nor do we ask any man's permission when we require him to obey it. Obedience to the law is demanded as a right; not asked as a favor."..."
  • All of us have a God in us
    by Earth Day, Kenya

    "...All of us have a God in us, and that God is the spirit that unites all life, everything that is on this planet. It must be this voice that is telling me to do something, and I am sure it'as the same voice that is speaking to everybody on this planet at least everybody who seems to be concerned about the fate of the world, the fate of this planet. Wangari Maathai-Noble Peace prize winner, Deputy Minister of Environment, founder Green Belt movement in Kenya...."

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  • Cancer Facts & Figures
    about Besides Lung Cancer

    Besides lung cancer, tobacco use also increases the risk for cancers of the mouth, lips, nasal cavity (nose) and sinuses, larynx (voice box), pharynx (throat), esophagus (swallowing tube), stomach, pancreas, kidney, bladder, uterus, cervix, colon/rectum, ovary (mucinous), and acute myeloid leukemia. Harvard Medical School
    about Eyesight Myth and Fact

    Myth: Staring at a computer screen all day is harmful to the eyes. Fact: Spending the day staring at a screen can tire or strain your eyes, but it will not hurt them. Make sure lighting doesn't create a glare on your screen. When spending long periods at your keyboard, take a break now and then to rest your eyes to reduce fatigue. Also, don't forget to blink. Your eyes need to stay lubricated to feel comfortable.

Circuit Breakers :

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ARTICLE INFORMATION :

Most non-electricians know little about circuit breakers. Are you planning to redo the wiring in your home? Using the wrong breaker can cause you a lot of power failures. Quiz your electrician to know more about breakers.

ARTICLE CONTENT :

A circuit breaker is an electrical device used to automatically break open an electrical circuit when it becomes overloaded. This is a safety precaution that can save a home or building from having a major fire or electrical disaster.

To determine the ideal breaker, you have to consider the type of voltage you are using, the trip point, and the overload protection. These are important factors for the safety of your home and family.

There are different types of voltage breakers; the low voltage circuit breaker is the most common type, which is used in homes. Low voltage breakers are the easiest way to install, since you only have to install them on breaker panels.

Miniature circuit breakers or MCBs use the lowest low voltage. It is known to carry electricity of not more than 100 amps; MCBs are also capable of holding electric charges of not more than 1,000 amps. Next to MCBs, are the Molded Case Circuit Breakers or MCCBs.

MCCBs are ideal for 1,000 amps and can safely disconnect from electricity that goes beyond ten times its capacity. They are also called a magnetic circuit breaker, because they use an electromagnetic power solenoid to break the circuit when there is too much electricity flowing through it.

Medium Voltage Circuit Breakers are the next type. Its capacity is to hold amps that can reach between 1,000 and 72,000 before they break. Their performance is relative to the model and brand. Westinghouse breakers are known for its quality of performance.

Medium Breakers are found in large buildings and businesses, and are enclosed in switchboxes or indoor cabinets. Under this type of breaker are three sub-types, vacuum, air, and SF6 breakers.

The vacuum breakers can maintain a power arc in a vacuum by letting air back into the breaker when it is tripped. An air Circuit breaker is equipped with two spring loaded contacts close together in an air-enclosed environment, when the breaker is tripped; the spring snaps open and pushes the contacts away from one another.

SF6 breakers have an arc produced in a chamber of sulfur hexafluoride gas, which reacts to the presence of higher than a regular voltage. It increases in density to stop the arc.

The high voltage breakers are the ones that are capable of holding more than 72,500 volts of electricity. They are found outdoors in a chain-link enclosure together with high voltage power lines. They are operated by solenoid switch which activates the fill the arc-chamber, when too much power flows through them.

The trip point is the second consideration in choosing the ideal circuit breaker. The point at which the breaker will trip can be set at low, medium or high sensitivity to prevent your wiring from heating.

Breaker overload protection is critical. Westinghouse breakers have overload protection that are similar to hydraulic and earth leakage breakers, providing custom protection. This type of circuit breaker senses ground faults and excessive flow of electricity.

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  • Relectric
    At relectric you will find the circuit breakers you want. We have many brands of circuit breakers you can choose from.

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  • November 30, 2014Date Added :
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