...Introduction to lightning and lightning arresters What are Long Flashover Arresters? Why do we need them? How do they work? What are their types? 2 What is a lightning stroke? It is an electric discharge between ◦ Cloud and earth ◦ Cloud and cloud ◦ Charge centers of the same cloud 3 Lightning stroke waveform 4 Types of lightning strokes Direct Stroke Indirect Stroke 5 What does lightning do? Strikes live power line jumps across insulator to reach grounded tower. Lightning channel across insulator acts as conductor causing a short circuit. Man-made power from live wire flowing through section of old lightning channel in an intensely bright arc. 6 Lightning arresters A device used on power systems above 1000 V to protect other equipment from lightning and switching surges Under normal operation the lightning arrester is off the line On the occurrence of over voltage air insulation across gap breaks down and arc is formed providing a low resistance path for the surge to the ground 7 Metal Oxide Lightning Arrester The metal oxide varistor (MOV) contains a material, typically granular zinc oxide, that conducts current (shorts) when presented with a voltage above its rated voltage They exhibit an extremely high resistance during normal operation and a very low resistance during overvoltages 8 What are LFAs? A new simple, effective and inexpensive system for lightning protection...
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...Turner 23 July 2014 Lightning Rod Attraction: Blunt Tip vs. Pointed Tip Abstract: This paper explores the effects that lightning rod tip geometry has on lightning. To determine the most effective tip geometry various types of rods including pointed, concave, blunt, flat, and conical were tested with electric pulses in a lab and in real lightning situations. It was observed that the blunt shaped rod was the most efficient shape for creating a path for lightning to the ground. In real lightning situations a smaller surface area generates far more corona emissions than a larger area. The increased corona emission almost prevents lightning from traveling the directed path. In the case of the blunt rod, the lesser emissions provided a desired path for the lightning to travel down. A lot of research was put in to find the ideal tip shape for lightning rods, and it was determined that the increased surface area directly correlates to how strong the electric field is at the tip of the lightning air terminal (LAT). Introduction: It is a beautiful and deadly natural occurrences. With a shock of several million volts per strike, and the capability to reach temperatures between fifteen-thousand and sixty-thousand degrees, lighting is one of the most powerful forces known to man. With all of that power lightning can cause a lot of damage. In North America lightning damage to equipment results in losses exceeding twenty-six billion dollars annually. Lightning strikes the ground around...
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...occurrences and detailed special checks for these µAbnormal Occurrences¶. 1.1 T YPES OF ABNORMAL OCCURRENCES The aircraft maintenance manual will normally list the types of abnormal occurrences needing special inspection. The list may vary, depending on the aircraft. The following items are a selection from a typical aircraft: y y y y y y y y y y y Lightning strikes High-intensity radiated fields penetration Heavy or overweight landing Flight through severe turbulence Burst tyre Flap or slat over-speed Flight through volcanic ash Tail strike Mercury spillage Dragged engine or e ngine seizure High-energy stop. 1.2 T YPES OF DAMAGE It is not intended to describe the types of damage applicable to every type of occurrence. It is more important to understand that, often, the damage may be remote from the source of the occurrence. In many cases the inspection would be made in two stages. If no damage is found in the first stage then the second stage may not be necessary. If damage is found, then the second stage inspection is done. This is likely to be a more detailed examination. 1.3 L IGHTNING STRIKES Both lightning strikes and...
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...types.He created the Franklin Stove, lightning rod, bifocals, and the reaching hand. He was a quotist and made many inspiring quotes about leadership and advice. He made many inventions. He made the bifocals for people to see because he wanted to cure the people that were losing their eyesight. He made the Franklin stove to stop the smoke coming out of the chimney but still have a nice warm fire. All of his inventions helped society in a couple ways. It made life way easier for us today. All of his...
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...location below the earth’s surface where the earthquake starts is called the hypocenter, and the location directly above it on the surface of the earth is called the epicenter. Sometimes an earthquake has foreshocks. These are smaller earthquakes that happen in the same place as the larger earthquake that follows. Scientists can’t tell that an earthquake is a foreshock until the larger earthquake happens. The largest, main earthquake is called the mainshock. Mainshocks always have aftershocks that follow. These are smaller earthquakes that occur afterwards in the same place as the mainshock. Depending on the size of the mainshock, aftershocks can continue for weeks, months, and even years after the mainshock! Causes of earthquakes and How earthquakes happen The earth has four major layers: the inner core, outer core, mantle and crust. (figure 2) The crust and the top of the mantle make up a thin skin on the surface of our planet. But this skin is not all in one piece – it is made up of many pieces like a puzzle covering the surface of the earth. Not only that, but these puzzle pieces keep slowly moving around, sliding past one another and bumping into each other. We call these puzzle pieces tectonic plates, and the edges of the plates are called the plate boundaries. The plate boundaries are made up of many faults, and most of the earthquakes around the world occur on these faults. Since the edges of the plates are rough, they get stuck while the rest of the plate keeps...
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...- "Lightning in Your Hand" Materials • Two Styrofoam plates • Clear tape (scotch tape) • Aluminum pie pan (8”-9” diameter) • A small piece of wool fabric Attach a Styrofoam strip (1” wide) to the center of the aluminum pie plate on the inside surface of the aluminum plate. This strip will work as a handle. You could also tape an inverted Styrofoam cup on the side to act as a handle. This works best on a cool dry day. If it is too hot and humid it will not work well. Humidity is the enemy of static electricity! Procedure Tape one Styrofoam plate in an upside down position on a table or desktop. Use two small pieces of clear tape at opposite edges. I) Rub the top of the Styrofoam plate with wool or rub across the back of the Styrofoam plate using the sleeve of your sweater. The Styrofoam plate is now charged because electrons from the wool have traveled to the Styrofoam plate. Lift up the aluminum plate with its Styrofoam handle and set it on the taped Styrofoam plate. • What do you feel when you touch the aluminum plate? II) Now lift up the aluminum plate by the handle and touch it with your other hand. • What happens? • What causes this to happen? • What happens if you set the aluminum plate back on the Styrofoam plate? • Why do you think this happens? III) Next take the second Styrofoam plate and rub the bottom with your sweater sleeve or wool. Try setting this second plate on top of the upside down taped Styrofoam plate that has been charged by rubbing. •...
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...Giant Waves/Tsunami A tsunami is a series of ocean waves that sends surges of water, sometimes reaching heights of over 100 feet (30.5 meters), onto land. These walls of water can cause widespread destruction when they crash ashore.The tidal wave starts at the back of the forest and works its way toward the beach, meaning that if you are unable to run to another sector, you’re definitely going to drown. The wave is just too wide and too powerful to survive. Even if you happen to outrun it, you wind up running into more water. 58:53 Costume with Fire The costumes do not use real fires. According to the 'The Hunger Games' novel the flame effect was so startling and so unexpected that one would assume it was not produced with flapping, lit silk. This would not be feasible in a costume anyway. To make realistic fire one needs moving flames and light. Silk or tissue paper can certainly fill the role of flames, but for a fiery effect they need to be in constant motion. This would mean installing fans of some sort in the costume. 1:04:20 Archery "When an arrow is released, it produces a great kinetic energy that causes the arrow to bend right, then left, then right, then left again etc. until it hits the target. First, when the arrow is released, the string moves to the left causing the arrow...
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...Abbey Ford AP Language and Composition 13 October 2014 Poem Analysis In his poem “First Storm and Thereafter,” Scott Cairns depicts a memory of a woman through cogent vocabulary and phrases. Cairns uses a slow shift in tone and contrasting words to describe the effect this haunting memory has on his mind and how it engulfs his future. In the first section of the poem, Cairns focuses on certain parts of a storm: lightning, thunder, and rain. Creatively, each component is compared to a sensory detail; lightning is to sight, as thunder is to sound, as rain is to touch. He is reminiscing on the ravishing and captivating memories with his love. The author claims that “fixed in memory is the rare quality of its lightning, as if those bolts were clipped from a comic book” (First Storm and Thereafter, 2-5). At first this generates the idea that everything is perfect, unblemished. As if it could be formed into a comic book and sell millions of copies. Whereas directly after, he describes the lightning as “fashioned with cardboard, daubed with gilt then hung overhead on wire and fine hooks” (First Storm and Thereafter, 7-10). This implies that the seemingly appealing memories offered are actually rotten on the inside. He uses the phrase “daubed with gilt” like an ornament. The gold makes the cardboard look pretty, but in reality it doesn’t withhold the charming effect it is fabricated to have. When describing the thunder Cairns says now he hears “…its grief–a moan, a long...
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...villanelles II. Subject Matter: A Poem: “Do Not Go Gentle Into That Good Night” III. Unlocking of Difficulty A. Vocabulary: Context Clues 1. Old age should burn and rave at close of day; a. Poor b. glow c. admire 2. Rage, rage against the dying of the light. a. Be angry b. calm c. exile 3. Because their words had forked no lightning a. Left b. restored c. split 4. Their frail deeds might have danced in a green bay a. Weak b. robust c. strong 5. Blind eyes could blaze like meteors and be gay a. Dim b. glare c. fly B. Background information (through pictures and illustrations) 1. Picture of a family. Explain the relationship of the parents to their children and vice versa in dealing with death. 2. Show video clips that portrays people’s survival against death. IV. Motivation Questions: Have you ever given your best when you knew it was useless? Do you know someone who has? Do you know someone who has been disturbed and frustrated by the way that death comes to everyone? Motive Questions: How did the speaker urge his father to fight against death? How did the speaker use the four different types of men to express his frustration towards his father’s acceptance of death? V. Reading of the Selection First, the teacher will provide copies of the poem/worksheet (See Appendix A). Next the teacher will let the students listen to an audio file that reads the poem. After listening, the teacher will play...
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...4 July 2012 The Formation of Storms and Tornadoes What are tornadoes and what role do thunderstorms play in the formation of tornadoes? The National Oceanic and Atmospheric Association (NOAA) defines a tornado as “a violently rotating column of air extending from a cumuliform cloud, such as a thunderstorm, to the ground (National Oceanic and Atmospheric Administration).” Not all thunderstorms will produce a tornado. Several factors and circumstances must be in place for the formation of a tornado to take place. Thunderstorms take place when moisture, unstable air masses, and lift are in the right place at the right time. A common misconception about tornadoes is that a tornado will form when "warm moist Gulf air meets cold Canadian air and dry air from the Rockies (Edwards)." Most thunderstorms will form under these conditions, but these conditions alone do not guarantee that a tornado will form. Even with the advanced technology available to meteorologists, much is still unknown about tornadoes, including why they form and what causes one storm to produce a tornado while another does not. All thunderstorms have air called an outflow that surrounds the entire storm system. While some tornadoes die when they become wrapped in this outflow air, the opposite may also occur in which a tornado is spawned as a result of outflow air conditions (Edwards). This unpredictability of tornadoes makes them very difficult for meteorologists to accurately forecast. A thunderstorm requires...
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...Chpt. 1 “There is a window in my attic, where I have gone so many times,” sang young Rose, listening to her favorite song that was on her ipod. Now Rose was not a regular little girl. Her hair had a black/blue tinge to it and she had rose-colored eyes. She had a cat named Lightning, since he had a white underbelly and white paws, the rest of him was a stormy black with spots of white which made him look gray. “Rose!” her father called. “Just a minute!” Rose replied, ripping her earphones out of her ears and stashing them in their safe spot. Just as she was going out her room door, she remembered that she needed to get her notebook. This notebook was the first one she had ever owned. She had to always put new pages in it so that she could keep...
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...Wes Flaa 10/26/15 Hubbard English A Work of Artifice The poem, “A Work of Artifice” written by Marge Piercy uses many different ways to describe her writings. It begins with a Bonsai tree in an ”attractive pot.” Figurative language is used to show how this Bonsai tree has the potential to grow to great hight and claims it,”could have grown eighty feet tall,” but is instead held back by the gardener- “But a gardener carefully pruned it”. The gardener is used to show the potential of humans and women in particular, can be “pruned” by the way they are raised or by the way others around them have effected them. The author employs the use of satire is in the title. By using the word “Artifice” she begins to imply something deceptive and cunning....
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...graph paper and label them with the voltage readings of your voltmeter. In step 10 you are asked “How far does this path go? Sketch this pattern on your graph paper and label the line with the voltage you chose” In step 12 you are asked to predict the path it would take by drawing a line with your colored pen or pencil. Questions: A. What generalizations can you make from this exploration? B. Where would a positive test charge have the least potential energy? A positive test charge would have the least potential energy next to the conductor at 0 volts. C. How much energy must you add to the system to move 1 electron 1 m in a direction along one of the equal potential lines? No work is needed to move 1 electron 1m in a direction along one of the equal potential lines D. If lightning strikes a tree 20 m away would it be better to stand facing the tree, your back to the tree, or your side to the tree? Assume your feet are a comfortable shoulder width apart. Explain your answer. If the person stood with the side facing the tree, the feet would be at different potentials and a dangerous shock could occur. If the field around the tree is uniform, facng back against the tree would place both feet I equal potential and no shock would occur. Facing away from the tree may be the best option, because the face would be protecting from debris and lightning Note: Your results will look different from the sample above since you will use...
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...The Hero’s Journey about The Lightning Thief. The world has changed ever since invaders from another life form has been threatening the safety of civilians. Percy Jackson is new to the life of being a half blood, he is the son of Poseidon. Poseidon is a god, ruler of the sea and water. Percy jackson is just now learning how to use his powers, but he decides to take on a huge battle to save his mom, and the world. Percy Jackson will follow the Hero’s Journey which was introduced by Joseph Campbell. The Hero’s Journey is based on a character whose life changes as he or she has to take on a difficult task in order to save or reach his or her task. In The lightning Thief Percy just found out he was a half blood which is when a god has a kid with a normal human. When you are a half blood, you need to be trained at...
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...Electricity Test Study Sheet NAME: _____________________________________________________ 1. Explain the Law of Electric Charges (pg. 462) ________________________________________ ________________________________________________________________________________ 2. What happens when a charged object is brought near a neutral object? (Explain what happens to the electrons within the object). ________________________________________________________________________________ 3. What is the Electrostatic Series ________________________________________________________________________________ Answer questions 1-4 based on the electrostatic series: Charging By Contact 1. An ebonite rod was rubbed with silk. (rod has more attraction for electrons) a) ADD THE CHARGES THAT WILL EXIST BEFORE FRICTION HAS OCCURRED Silk Rod Charge: ___________________ Charge: ___________________ b) ADD THE CHARGES THAT WILL EXIST AFTER FRICTION HAS OCCURRED FRICTION HAS OCCURRED Silk Rod Charge: ___________________ Charge: ___________________ c) ADD THE CHARGES THAT WILL EXIST WHEN THE ROD TOUCHES NEUTRAL PAPER (rod has more attraction for electrons than paper) Paper Rod Charge: ___________________ Charge: ___________________ ...
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