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A new simple, effective and inexpensive method for lightning protection of medium voltage overhead distribution line is using long flashover arresters (LFA).www.viewzoft.com. A new long flashover arrester model has been developed. It is designated as LFA-M. It offers great number of technical and economical advantages.
The important feature of this modular long flashover arrester (LFA-M) is that it can be applied for lightning protection of overhead distribution line against both induced overvoltages and direct lightning strokes. The induced over voltages can be counteracted by installing a single arrester on an overhead line support (pole). For the protection of lines against direct lightning strokes, the arresters are connected between the poles and all of the phase conductors in parallel with the insulators.
Lightning is an electrical discharge between cloud and the earth, between clouds or between the charge centers of the same cloud. Lightning is a huge spark and that take place when clouds are charged to at a high potential with respect to earth object (e.g. overhead lines) or neighboring cloud that the dielectric strength of the neighboring medium(air) is destroyed.
TYPES OF LIGHTNING STROKES
There are two main ways in which the lightning may strike the power system . They are
1. Direct stroke
2. Indirect stroke
Direct Stroke
In direct stroke, the lightning discharge is directly from the cloud to the an overhead line. From the line, current path may be over the insulators down to the pole to the ground. The over voltage set up due to the stroke may be large enough to flashover this path directly to the ground. The direct stroke can be of two types
1. stroke A
2. stroke B
In stroke A, the lightning discharge is from the cloud to the subject equipment(e.g. overhead lines). The cloud will induce a charge of opposite sign on the tall object. When the potential between the cloud and line exceed the breakdown value of air, the lightning discharge occurs between the cloud and the line.
In stroke B the lightning discharge occurs on the overhead line as the result of stroke A between the clouds. There are three clouds P,Q and R having positive, negative and positive charge respectively. Charge on the cloud Q is bound by cloud R.If the cloud P shift too nearer to cloud Q,Then lightning discharge will occur between them and charges on both these cloud disappear quickly. The result is that charge on cloud R suddenly become free and it then discharges rapidly to earth, ignoring tall object.
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Rapid advances in bioinformatics are providing new hopes to patients of life threatening diseases. Gene chips will be able to screen heart attack and diabetics years before patients develop symptoms.www.viewzoft.com. In near future, patients will go to a doctor's clinic with lab- on- a- chip devices. The device will inform the doctor in real time if the patient's ailment will respond to a drug based on his DNA.
These will help doctors diagnose life-threatening illness faster, eliminating expensive, time-consuming ordeals like biopsies and sigmoidoscopies. Gene chips reclassify diseases based on their underlying molecular signals, rather than misleading surface symptoms. The chip would also confirm the patient's identity and even establish paternity.
Bioinformatics is an inter disciplinary research area. It is a fusion of computing, biotechnology and biological sciences. Bioinformatics is poised to one of the most prodigious growth areas in the next to decades. Being the interface between the most rapidly advancing fields of biological and computational sciences, it is immense in scope and vast in applications.
Bioinformatics is the study of biological information as it passes from its storage site in the genome to the various gene products in the cell. Bioinformatics involves the creation and computational technologies for problems in molecular biology. As such ,it deals with methods for storing, retrieving and analyzing biological data, such as nuclei acid (DNA/RNA)and protein sequence, structures, functions, path ways and interactions. The science of Bioinformatics, which is the melding of molecular biology with computer science is essential to the use of genomic information in understanding human diseases and in the identification of new molecular targets of drug discovery.
New discoveries are being made in the field of genomics, an area of study which looks at the DNA sequence of an organism in order to determine which genes code for beneficial traits and which genes are involved in inherited diseases.If you are not tall enough, the stature could be altered accordingly. If you are weak and not strong enough, your physique could be improved. If you think this is the script for a science fiction movie, you are mistaken. It is the future reality.
Evolution Of Bioinformatics
DNA is the genetic material of organism. It contains all the information needed for the development and existence of an organism. The DNA molecule is formed of two long polynucleotide chains which are spirally coiled on each other forming a double helix. Thus it has the form of spirally twisted ladder. DNA is a molecule made from sugar, phosphate and bases.
The bases are guanine (G), cytosine(C)adenine(A) and thiamine(T).Adenine pairs only with Thiamine and Guanine pairs only with Cytosine. The various combinations of these bases make up with DNA. That is; AAGCT, CCAGT, TACGGT etc. An infinite number of combinations of these bases is possible. And then the gene is a sequence of DNA that represents a fundamental unit of heredity. Human genome consists of approximately 30,000 genes, containing approximately 3 billion base pairs.
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The first use of Audio-Animatronics was for Walt Disney's Enchanted Tiki Room in Disneyland, which opened in June, 1963. The Tiki birds were operated using digital controls; that is, something that is either on or off. Tones were recorded onto tape, which on playback would cause a metal reed to vibrate.www.viewzoft.com. The vibrating reed would close a circuit and thus operate a relay. The relay sent a pulse of energy (electricity) to the figure's mechanism which would cause a pneumatic valve to operate, which resulted in the action, like the opening of a bird's beak. Each action (e.g., opening of the mouth) had a neutral position, otherwise known as the "natural resting position" (e.g., in the case of the Tiki bird it would be for the mouth to be closed). When there was no pulse of energy forthcoming, the action would be in, or return to, the natural resting position.
This digital/tone-reed system used pneumatic valves exclusively--that is, everything was operated by air pressure. Audio-Animatronics' movements that were operated with this system had two limitations. First, the movement had to be simple--on or off. (e.g., The open and shut beak of a Tiki bird or the blink of an eye, as compared to the many different positions of raising and lowering an arm.) Second, the movements couldn't require much force or power. (e.g., The energy needed to open a Tiki Bird's beak could easily be obtained by using air pressure, but in the case of lifting an arm, the pneumatic system didn't provide enough power to accomplish the lift.) Walt and WED knew that this this pneumatic system could not sufficiently handle the more complicated shows of the World's Fair. A new system was devised.
In addition to the digital programming of the Tiki show, the Fair shows required analog programming. This new "analog system" involved the use of voltage regulation. The tone would be on constantly throughout the show, and the voltage would be varied to create the movement of the figure. This "varied voltage" signal was sent to what was referred to as the "black box." The black boxes had the electronic equipment that would receive the signal and then activate the pneumatic and hydraulic valves that moved the performing figures. The use of hydraulics allowed for a substantial increase in power, which was needed for the more unwieldy and demanding movements. (Hydraulics were used exclusively with the analog system, and pneumatics were used only with the tone-reed/digital system.)
There were two basic ways of programming a figure. The first used two different methods of controlling the voltage regulation. One was a joystick-like device called a transducer, and the other device was a potentiometer (an instrument for measuring an unknown voltage or potential difference by comparison to a standard voltage--like the volume control knob on a radio or television receiver). If this method was used, when a figure was ready to be programmed, each individual action--one at a time-- would be refined, rehearsed, and then recorded. For instance, the programmer, through the use of the potentiometer or transducer, would repeatedly rehearse the gesture of lifting the arm, until it was ready for a "take."
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