Chapter 2 Mirror Design For Optical Telescopes The reflector mirror is the most important component of an astronomical optical telescope. This chapter provides discussions on the requirements for astronomical optical mirrors; the ways to reduce mirror weight‚ mirror cost‚ and mirror materials; the methods of mirror figuring‚ polishing‚ and surface coating; the design of mirror support mechanism; the concept of mirror seeing; and the stray light control. Emphasis is placed on various mirror
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another section. Which are evaporation‚ radiation‚ convection and radiation ( Jeng‚ 1998 ). Evaporation is when liquid changes into a vapor at a temperature below the boiling point. Evaporation takes place at the surface of a liquid‚ where molecules with the highest kinetic energy are able to escape. When this happens the average kinetic energy of the liquids is lowered and its temperature decreases ( The American Heritage‚ 2015 ). Convection is the transfer of heat by the circulation of movement
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figure. Given: Ls = 2 mm = 0.002 m Lc = 3 mm = 0.003 m ks = 17 W/m-K kc = 372 W/m-K Q.3 A 4 mm diameter spherical ball at 50oC is covered by a 1 mm thick plastic insulation (k = 0.13 W/m-K). The ball is exposed to a medium at 15oC‚ with a combined convection and radiation heat transfer coefficient of 20 W/m2-K. Determine if the plastic insulation on the ball will help or hurt heat transfer from the ball. Q.4 Prove that if k varies linearly with T in a slab‚ and if heat transfer is one-dimensional and
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The History of plate tectonics Before the plate tectonics revolution of the 1960’s geographers had a very basic understanding of global geological phenomena’s. while there had been many theory’s put fort that were used to try and explain these phenomena’s none had been completely successful till finally In the 1960’s The theory of plate tectonics was put forth. It was truly a unifying concept as it helps us to explain and finally understand many different aspects of geography such as the geography
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Part 1 of 1 - 100.0/ 100.0 Points Question 1 of 22 4.0/ 4.0 Points Who proposed that all of the present continents were once joined together in a single supercontinent called Pangaea? A.Alfred Wegener B.Charles Darwin C.Arthur Holmes D. Harry Hess Answer Key: A Question 2 of 22 4.0/ 4.0 Points The scientific community rejected the theory of plate tectonics because Alfred Wegener could NOT A.identify a mechanism to move the continents. B.disprove competing theories
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Science meets Real Life Cheryl Hankins SC300: Big Ideas in Science: From Methods to Mutation There are two different ways to use the scientific method. The five step method involves observing/research‚ hypothesis‚ prediction‚ experiment‚ and conclusion (Understanding and Using the Scientific Method‚ 2011). The seven step method involves observation‚ question‚ research‚ guess‚ experiment‚ analyze data‚ and conclusion (Trefil & Hazen‚ 2010). Whether using the five step method or the seven step
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UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS International General Certificate of Secondary Education * 2 7 2 0 7 8 6 3 0 4 * 0648/01 FOOD AND NUTRITION May/June 2013 Paper 1 Theory 2 hours Candidates answer on the Question Paper. No Additional Materials are required. READ THESE INSTRUCTIONS FIRST Write your Centre number‚ candidate number and name on all the work you hand in. Write in dark blue or black ink. You may use a soft pencil for any diagrams or graphs. Do
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computer generates less heat and is made of recyclable materials. A dishwasher has a booster heater that raises water temperature to the required temperaturefor dish washing‚ it also uses about a half the water required for manual washing. A convection oven can cut energy use by 20% because the heat comes from the bottom and it blows the heat around to cook the food. A typical new refrigerator uses one quarter the energy of a 1974 model. In conclusion‚ the article “An Efficient
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holding the cup. Coffee cup holder prevents burned fingers The holder is corrugated‚ such that are there air gaps and only the ridges touch the cup. Coffee cup holder has ridges inside The air gaps mean the heat transfer must be done by convection‚ which is less effective than conduction. With only the ridges of the holder touching the hot cup‚ much less heat transfer by conduction occurs. ii)Wear full lab equipment such as lab coat‚googles‚and gloves to reduce exposure of skin. G)
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‘Evaluate how plate tectonics theory helps our understanding of the distribution of seismic and volcanic events’ In 1912‚ Alfred Wegener published his theory that a single super continent named Pangaea once existed about 300 million years ago. He proposed that Pangaea then later split into two continents of Laurasia in the north and Gondwanaland in the south and that today’s continents were the result of further splitting of these two land masses. Where the plates split are known as plate boundaries
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