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  1. Problem: a huge percentage of airplane emissions come from long-haul travel. Are electric planes the solution? Companies around the world are working to develop electric airplanes. The hope is that advances in battery technology will enable efficient, emissions-free aircraft to replace kerosene-burning Jets. Considering air transportation accounts for around 4 percent of the global climate change impact, electric airplanes are seen as a key technology for cleaning up the transportation sector. The London-based non-profit Fellow Travelers assessed the potential carbon emissions mitigation could be accomplished by switching British aviation from Jets to electric propulsion. The results were not encouraging. The first planes to go electric - short-range, low-capacity aircraft - are also the ones that contribute the least amount of carbon pollution. Even If electric planes take over all flights of less than 1,500 km - about 900 miles - they will only make a small dent in carbon emissions. According to the data from Fellow Travelers, 87 percent of aviation-related carbon emissions are due to flights longer than 1,500 km, and the vast majority can be attributed to long-haul aircraft. The report focused on the United Kingdom, but the results are generally applicable. Electric jets won't solve the aviation emissions problem. Jeffrey Winters
  2. just take mouse on image,,,,, it will show you image tools
  3. First job one does is as GET - Graduate engineer trainee.... where he is sure to get practical training.... however we have seen even do not study theory properly..... do we understand why calculations are done.....why and whats assumptions are we making ?
  4. Dear Mechanical Engineers We invite you for the following discussion Application of Artificial Intelligence & Machine Learning in Mechanical Engineering How can we apply AI in filed of Machine learning ? You can consider your workspace, your industry.....let all of us have come together with ideas...
  5. Dear Members, we will share quiz links, questions, and discussion topics directly with whatsapp group. Please join only 1 group as - all groups will receive same posts Only for Mechanical Engineers They will be admin only groups ... you will not be allowed to post - Marketing people should not join these groups. All interaction will take place via websites Mechanical Engineering Group 101 https://chat.whatsapp.com/GUCrHpf4igeJxRXjthnzXw Mechanical Engineering Group 102 https://chat.whatsapp.com/E7yNk8JUQEt1WMx0X4wMa5 Mechanical Engineering Group 103 https://chat.whatsapp.com/FpW53FD87QDBeHKrAiHjpf Mechanical Engineering Group 104 https://chat.whatsapp.com/IX6YNa5DKLjEsscStmsqrz Mechanical Engineering Group 105 https://chat.whatsapp.com/GSmS6JPOovk74FOS7pZBh9 Mechanical Engineering Group 106 https://chat.whatsapp.com/JqZRrIkVNVH7NV04DVKvCJ Mechanical Engineering Group 107 https://chat.whatsapp.com/DCDneEo5lEz0zGpc4HSYSG Mechanical Engineering Group 108 https://chat.whatsapp.com/JqwB5O64VMc4EhQMQ2f27E Mechanical Engineering Group 109 https://chat.whatsapp.com/G4ULDyFGZkj94ssuzJtcvx Mechanical Engineering Group 110 https://chat.whatsapp.com/HOblns1YWHzB3QtocA7v8d Mechanical Engineering Group 111 https://chat.whatsapp.com/GxGCo8asPVM2CNWgFFCfLM Mechanical Engineering Group 112 https://chat.whatsapp.com/KixunbNehYy5942lRbtaHQ Mechanical Engineering Group 113 https://chat.whatsapp.com/IZ7TYGtHjp4Ff2I7zYtmBF Mechanical Engineering Group 114 https://chat.whatsapp.com/LLRZqvgbwDP4S25BaHRJj5 Mechanical Engineering Group 115 https://chat.whatsapp.com/Exb4vVx9eGj7nxCFhw4jyr Mechanical Engineering Group 116 https://chat.whatsapp.com/HiwBwLkNhWkA2Z8ZsAZn8U Mechanical Engineering Group 117 https://chat.whatsapp.com/IZ0YqCnLlHW3lcjoICrVUM Mechanical Engineering Group 118 https://chat.whatsapp.com/FCKZps8PBxlHbqd7k9zuo2 Mechanical Engineering Group 119 https://chat.whatsapp.com/JRa1UtaXjmv6qPLFEMlPj4 Mechanical Engineering Group 120 https://chat.whatsapp.com/JLCN7NeoWOEEIVPGCW4VkO Mechanical Engineering Group 121 https://chat.whatsapp.com/FTu61h8VYUALQc0uibTAsx Mechanical Engineering Group 122 https://chat.whatsapp.com/J5fZ0tuUllI0sDLx9xIoqB Mechanical Engineering Group 123 https://chat.whatsapp.com/Ct4DGT9GGVx6QJRy3ZSQ25 Mechanical Engineering Group 124 https://chat.whatsapp.com/FNNOGrnEho9311b90EwHqq Mechanical Engineering Group 125 https://chat.whatsapp.com/LYHENL4YTu75I0IbmHXoZm Mechanical Engineering Group 126 https://chat.whatsapp.com/HFdnyhFZVvZ4qgeR31qudu Mechanical Engineering Group 127 https://chat.whatsapp.com/JyyuxSxDea2LMUtnAUAECK Mechanical Engineering Group 128 https://chat.whatsapp.com/DfHWnONH2wUBBXXfeoG3U3 Mechanical Engineering Group 129 https://chat.whatsapp.com/KCxgmcuZHhL7B35uLSdyYu Mechanical Engineering Group 130 https://chat.whatsapp.com/BV50dI8BWpC6dB4S9fhTPC Mechanical Engineering Group 131 https://chat.whatsapp.com/IFUzcriJWfn5jrKRh6DtIo
  6. 1. The characteristics of a material that are displayed when a force is applied to the material 2. The stress at which a material exhibits a specified deviation from proportionality of stress and strain. 3. The stress developed at the outer fibre when a material is loaded as a simply supported beam and deflected to a certain value of strain. 4. The serviceability factor related with the mechanical properties like impact strength, notch sensitivity. 5. The mechanical properties like bend radius, percentage elongation and percentage reduction in area are related with ...... 6. When one is interested in attribute of durability of a material, he must look for properties like hardness, wear resistance and . 7. Modulus of elasticity and flexural modulus refer to ...... of the material. 8. The material characteristics that relate to the structure of a material and its formation from other elements. 9. The structure of a polished and etched metal as revealed by microscope. 10. The ordered, repeating arrangement of atoms or molecules in a material. 11. The ability of a material to resist deterioration by chemical or electrochemical reaction with its environment. 12. The properties like thermal conductivity, refractive index, specific heat, dielectric strength fall under the category of ..... 13. The temperature at which ferromagnetic materials can no longer be magnetised by outside forces. 14. The ratio of the velocity of light in vacuum to its velocity in another material. 15. The temperature at which a polymer under a specified load shows a specified amount of deflection 16. The highest voltage an insulating material of a specified thickness can withstand for a specified time without occurrence of electrical breakdown through its bulk. 17. A hard and brittle alloy of iron, carbon (between 1.8 to 3%), and silicon. 18. Material used for machine housings and frames due to its high compression strength and good vibration absorption properties. 19. Cast iron which contains carbon as free carbon in the form of graphite. 20. Cast iron in which the carbon is present in the combined form as iron carbide. 21. Cast iron which contains graphite in the form of small spheres/nodules. 22. The free carbon in grey cast iron acts as an excellent ...... during machining and offers little frictional resistance. 23. Black heart, white heart, and pearlitic cast irons fall under the category of ...... 24. Which cast iron has good ductility as cast ? 25. Spheroidal graphite iron having tensile strength of 900 N/mm' and elongation of 2% is designated as ...... 26. A mechanical mixture of pig iron and distributed silicate slag. 27. The material used for chains, crane hooks, bolts subjected to shock loads etc. because it is malleable, ductile and tough. 28. Which alloying element in cast iron improves machinability, hardness, strength and corrosion resistance ? 29. Which alloying element in cast iron checks the formation of graphite and promotes the formation of carbides? 30. Which alloying element in cast iron improves strength and wear resistance ? 31. The resistance to corrosion of steel is increased by adding ...... 32. In order to eliminate blow holes in castings, ...... is added to steel. 33. Addition of boron to steel improves ...... 34. Red hardness is imparted to steel by adding ...... 35. Which alloying element in steel removes oxygen in steel making and facilitates rolling and forging? 36. Which alloying element in steel promotes tenacious oxide film to aid atmospheric corrosion resistance ? 37. Machinability of steel is improved by adding ...... 38. Simple alloys of iron and carbon with no other alloying element. 39. A group of steels with carbon content varying upto about 1% and total alloy content below 5%. 40. A solid formed by the combination of metallic and non-metallic elements. Ans. 1. Mechanical property 2. Yield strength 3. Flexural strength 4. Toughness 5. Formability 6. Fatigue strength 7. Rigidity 8. Chemical properties 9. Microstructure 10. Crystal structure 11. Corrosion resistance 12. Physical properties 13. Curie point 14. Refractive index 15. Heat distortion temperature 16. Dielectric strength 17. Cast iron 18. Cast iron 19. Grey cast iron 20. White cast iron 21. Spheroidal or nodular graphite iron 22. Lubricant 23. Malleable cast iron 24. Spheroidal graphite 25. SG 900/2 26. Wrought iron 27. Wrought iron 28. Nickel 29. Chromium 30. Molybdenum 31. Chromium 32. Phosphorus 33. Rolling qualities 34. Tungsten 35. Silicon 36. Copper 37. Lead 38. Carbon steels 39. Alloy steels 40. Ceramic.
  7. (a) Describe the steps usually considered in the process of material selection. (b) How material selection is done using decision theory. Ans. (a) Like any other aspect of engineering design, material selection is also equally important aspect. Material of part depends on the requirements of the part, number of parts needed, and manufacturing process to be adopted to make the part. The material selection primarily depends upon its properties and several other factors like availability, economic aspects, etc. As regards properties of materials, all the following properties need to be considered, (i) chemical (characteristics that relate to the structure of a material and its formation from other elements), (ii) physical (characteristics that are determined by nature, like electrical, magnetic, thermal, etc.), (iii) mechanical (strength, ductility, toughness, rigidity and behaviour under application of force). (iv) dimensional (relating to available size, shape, microtopography and tolerances), (v) technological (machinability, weldability, castability, forgability, bendability, malleability, ductility, hardenability, etc. all relating to manufacturing process). It is essential to establish the performance requirements that the material must meet; then select the appropriate materials for evaluation, and finally select the material that best meets the performance requirements and economic constraints. It is best to consider the alternatives from a wide gambut of materials, viz. ferrous materials (cast iron, cast steel, mild steel, alloy steel, carbon steel, tool steel etc.), non-ferrous materials and their alloys, plastics, ceramics, elastomers, composite materials, etc. Having selected the material from consideration of properties, next step is to check availability, i.e. whether material is readily available, lead time for procurement, quantity required, nature of supplies, whether any special method required to manufacture. The final step is to examine economics, i.e. the cost should be minimum. Cost of a material consists of the initial cost, processing cost and maintenance cost
  8. Ans. 1. (i), 2. (e), 3. (a), 4.(j), 5. (b), 6. (h), 7. (c), 8. (f), 9. (g), 10. (d).
  9. Ans. 1. (j) 2. (f) 3. (i) 4. (a) 5. (l) 6. (d) 7. (b) 8. (k) 9. (g) 10. (c) 11. (h) 12. (e)
  10. Ans. 1. (f) 2. (i) 3. (a) 4. (g) 5. (b) 6. (h) 7. (d) 8. (c) 9. (e).
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