INTRODUCTION In these days people are trying to find new energy sources. Because present energy sources are running down. So‚ alternative energy is so popular in these days. Because it has no danger to human life like nuclear powerplants‚ it is free to use and it has no waste. There are three types of alternative energy sources: Solar‚ wind and water. This report will be about solar energy. Its purpose is giving some information about solar energy to mechanical engineering students and
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grown through a process known as Czochralski (CZ) method. CZ ingot growth requires chunks of virgin polycrystalline silicon which are placed in a quartz crucible along with small quantities of elements called dopants - the most common of which are boron‚ phosphorus‚ arsenic and antimony. The materials are heated to a temperature above the melting point of silicon‚ 1420 degrees Celsius. Once the polycrystalline and dopant combination has been liquefied‚ a single silicon crystal‚ the seed‚ is positioned
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Introduction Our world today is infested and becoming way more dangerous with all these chemicals. In an effort to increase productivity and confine bigger market shares‚ the use of fertilizers‚ pesticides‚ food additives such as dyes and additives has become so common that artificial ingredients are now outnumbering natural ingredients on many food content labels‚ and it is the opinion of many experts that this forever increasing use of artificial fertilizers‚ pesticides‚ and chemical additives
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2010 HIGHER SCHOOL CERTIFIC ATE EXAMINATION Physics Centre Number Section I (continued) Part B – 55 marks Attempt Questions 21–32 Allow about 1 hour and 40 minutes for this part Student Number Answer the questions in the spaces provided. These spaces provide guidance for the expected length of response. Show all relevant working in questions involving calculations. Question 21 (2 marks) The optimum angle for safe re-entry of a space vehicle into Earth’s atmosphere is angle B. Outline
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HISTORY OF CUTTING TOOL MATERIALS • Cutting tool used during the industrial revolution in 1800 A.D • First cutting tool was cast using crucible method (1740) and slight hardened by H.T. • 1868: R. Mushet found by adding Tungsten we can increase hardness and tool life ( Air Quenching) • F.W.Taylor in Pennsylvania did the most basic research in metal cutting between 1880-1905 • Invented high speed steel (better H.T. process) • Better alloy
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Description Did you know that diatomic molecules make up majority of the Earth’s atmosphere? The prefix “di” means ‘’two’’ in Greek‚ so these diatomic molecules are made up of two atoms. In this lesson‚ we will discuss diatomic molecules and go over some examples. !!!What is a Diatomic Molecule? Diatomic molecules are all around us. The Earth’s atmosphere is mainly composed of about 78% oxygen and 21% nitrogen. The oxygen and nitrogen present in the atmosphere are both in the form of ‘’diatomic
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plastics‚ lead‚ tin‚ copper‚ silicon‚ beryllium‚ carbon‚ iron and aluminum. • Laments found in small amounts include cadmium‚ mercury‚ and thallium. • Elements found in trace amounts include americium‚ antimony‚ arsenic‚ barium‚ bismuth‚ boron‚ cobalt‚ europium‚ gallium‚ germanium‚ gold‚ indium‚ lithium‚ manganese‚ nickel‚ niobium‚ palladium‚ platinum‚ rhodium‚ ruthenium‚ selenium‚ silver‚ tantalum‚ terbium‚ thorium‚ titanium‚ vanadium‚ and yttrium. • Mercury: found in fluorescent tubes (numerous
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Introduction Many schools of thought and individual researchers have reached the conclusion that state-centric approaches fail to examine and analyze international elations as they have changed in the past century. The different leakages of the state-centric theories like the fact that states nowadays are multinational and are not constituted by only one nation (Baylis et al‚ 2008) in combination with the existence of other entities in the international arena apart from states has created the
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itself. This variable varies depending on the ph tendency‚ in particular‚ nutrients like phosphorous‚ potassium ‚sulphur‚ calcium and magnesium tend to drastically decrease in more acidic ph conditions (<6.0)‚ on the other hand iron‚ manganese‚ boron‚ copper and zinc tend to lack in alkaline enviroments (>7.5) [figure 1]. The importance of these types of nutrients varies depending on the species of plant‚ in this case radish tends to show higher concentrations of Potassium‚ Calcium‚ Magnesium
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discovered that the composition of the atmosphere does not change with decreasing pressure (increasing altitude). They also discovered that water is formed by two parts of hydrogen and one part of oxygen (by volume). ▪ 1808 - He was the co-discoverer of boron. ▪ 1810 - In collaboration with Louis Thenard‚ he developed a method for quantitative elemental analysis by measuring the CO2 and O2 evolved by reaction with potassium chlorate. ▪ 1811 - Gay-Lussac recognized iodine as a new element‚ described
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