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  1. Mechanics Corner A Journal of Applied Mechanics and Mathematics by DrD © Machinery Dynamics Research, 2017 Last Post Time to Hang It Up This will be the final post of Mechanics Corner here on Mechanical Engineering Forums. It has run almost exactly two years, and there have been ups and downs along the way. In this final post, I want to reflect a bit on my original goals for the blog, and also on what has actually happened. When our host first proposed to me that I might write a blog for ME Forums, I was excited about it. About half of my career had been spent in engineering education, and I always loved working with students. It seemed like a way to get back to something that I had long enjoyed, and so I accepted his suggestion. A long time ago, back when I was about 14 or 15 years old, in Junior High School, my shop teacher mentioned, in an off-hand way in class, that various curves could be described mathematically. I’d never heard that before, but I thought immediately, “This has interesting possibilities.” Moving ahead a few years, I discovered that I wanted to study and build my career around was the area known as Applied Mechanics, although it was a time before I first heard that term. In my freshman physics class, I discovered the laws of motion, and thought to myself, “This is great stuff! I can use math to describe how things move!” All of that happened back in the 1950s, and I’m still doing the same thing today (some might say I am in a rut!). As a teacher, I taught mostly undergraduate engineering courses, although I taught my share of graduate courses as well. It was the undergraduate courses that I liked most, because I firmly believe that the economy of a nation is strongly dependent on the quality of the baccalaureate level engineers produced in that nation. Engineers with graduate degrees are valuable as well, but the vast majority of the national engineering workload falls to BS level engineers. Thus, I envisioned Mechanics Corner as a sort of continuation of the several undergraduate courses I most enjoyed teaching — kinematics, dynamics of machines, vibrations, and mechanics of materials. For the most part, I have stuck to the plan, so that most of the technical posts I have made have dealt with problems that I considered suitable for undergraduate engineering students, say perhaps, junior level. I have posted a few topics from my industrial experience, but those have been situations that baccalaureate level engineers would be expected to handle. Now I knew it would not be exactly like continuing to teach my classes. In particular, you would not have any homework or tests, and I would not have any grading to do – a win-win, or so I thought. I did hope, that even with no assigned homework, readers would take an interest in the problems discussed, even to the point of working through the details for themselves (I was terribly naive, apparently!). I knew from my own experience that the only way I ever really learned a new idea was to get in and work with it, work some problems, make some numbers, plot some curves, until I really understood what it was all about. I’ll venture to say that nobody ever learned any technical material simply by reading only. In actual fact, in the early days, I had one or two folks say that they would in fact work through the problems, so I was encouraged. What I was not prepared for, however, was the fact that the vast majority never seemed to even read very carefully, much less work through the problems! The questions that have come, and there have been a few, have largely been about matters totally unrelated to the posts. The most common question has been, “Suggest a topic for my final project,” which relates to not a single post. Needless to say, that aspect of my vision was totally unfulfilled. But there is another side. I ventured to write a few “philosophical” articles, items dealing with academic integrity and cheating, with how to ask for help, with how to write a report or a paper, and various other matters. I really thought all of this would be considered obvious and trivial, so I was completely unprepared for the excitement that some of these articles generated. There were, in some cases, many, many comments, and people seemed to really be interested. I’m left to wonder: why? Are these ideas foreign to the culture of India and SE Asia? Are these things not all taught at home and in the public schools? I don’t know, but there was a lot of interest in these matters. But Mechanics Corner was intended to be primarily a technical blog, and there, it just did not excite the interest of the readership. As time passed, there was less and less interest. First, the comments dropped off to just about zero, and later, there were fewer and fewer who even bothered to “like” the articles. Finally, the number of reads has dropped to almost nothing (there may be no one left to read this final note). Well, there could hardly be any more clear indication that it is time to stop. I asked for opinions about this from some of the administrators, and was told that the blog was just over the heads of the readership. That makes me sad; that was never the intent. If it is true, I do not see how engineering has a very bright future among this readership. Even so, I wish all of you the best for your careers. I hope that you are able to find rewarding and beneficial work in which you will be happy and make a real contribution to your societies. To use an old cowboy metaphor perhaps familiar to many of you from Bollywood, “It is time to hang up the bridle and saddle, and say, ‘Adios’ (Adios is literally, “to God”).
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  2. There has always been a debate and discussion among all engineering students about which engineering course is the best? Students always love discussing about the best branch of engineering. Though this is a proven fact and it needs no discussion that mechanical engineering is the best still I will be providing 10 reasons over here which make mechanical engineering The Best among all other branches of engineering. #1 Evergreen Field: Mechanical engineering is an evergreen field. Applications of mechanical engineering have spread over such a wide spectrum that it has penetrated into almost every industry. Mechanical engineering got its application started right from the birth of this universe and it will continue till the end of this universe. #2 Mother Of All Engineering Disciplines: Yeah it’s mother of all engineering disciplines and you know it! Mechanical engineering links all engineering disciplines together and provides a base for all engineering education. #3 Everything Is Mechanical: Mechanical engineering has its application in all fields of life. May it be medicine, construction, automobile or even software and IT industry. Everything you see around you involves mechanical engineering to some extent. #4 Everlasting Scope: Scope of mechanical engineering is everlasting. Mechanical engineering graduates can find career placements in almost every sector, right from construction sector to steel industry and from automobile to software. #5 Best Job Offers: Mechanical engineers get best job offers after graduation. It’s one of the highest paid jobs all over the world. #6 Social Status: Mechanical engineers are respected in every society. They possess a respectful social status among masses. They are like global ambassadors. Wherever they go, they are treated with respect. #7 Most Interesting: Mechanical engineering involves study of some of the most interesting phenomena of science and engineering. The basic focus during study is on subjects such as thermal engineering, fluid sciences, machine design, industrial engineering and production engineering. #8 Even GOD Loves ME: Ever thought GOD also implemented mechanical engineering in nature? Motion of your body, arms, hands and feet involves mechanical engineering. Your heart pumps blood and it runs through all your veins. This is again application of mechanical engineering. The more you look into nature with the eye of a mechanical engineer, you will find more application of it. #9 Best Lifestyle: Do you need a best lifestyle to live in? Mechanical engineering offers you one of the best lifestyles. It’s like a dream come true. #10 Vast Industry: Mechanical engineering industry is vast. Every industry needs mechanical engineers to run its business smoothly. Do you have more reasons to say? Don’t forget to comment. Let us see how many reasons we can gather here in comments. I hope you enjoyed reading 10 reasons why mechanical engineering is the best course. No doubt It's best engineering course and best engineering branch!
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  3. 1. What are the differences between true stress, engineering stress, proof stress. 2. What do you men by factor of safety and what is its significance 3. What do you mean by Young’s modulus, modulus of rigidity and bulk modulus. 4. What do you mean by resilience. 5. What is pure torsion and what do you mean by flexural igidity. 6. What is the difference between endurance limit stree and endurance strength. 7. What do you understand by efficiency of riveted joint. 8. What is caulking and fullering in riveted joint. 9. What do you mean by stress conc. Factor and what are the methods to reduce stress conc. 10. Why stress conc. Is more serious in brittle materials. 11. What do you mean by fatigue . 12. Springs are subjected to which type of streses. 13. What are the difference between through bolt, tap bolt and stud. 14. What is check nut and what is the function of washer. 15. Cotter and knuckle joints take which type of load and where they are used. 16. What are the difference types of couplings and what is their function. 17. What is the function of key and which type of stress they are subjected to? 18. Generally shafts are subjected to which type of stress. 19. What are the difference types of mechanical drives and which is the best for different situations. 20. What is the function of a bush why it is phosphor bronze. 21. What are difference types of threads and which threads are used for power transmission and why. 22. Why the pulley arms are elliptical in cross section and it is made up of cast iron. 23. Why it is required to change the all V belt if one of them is broken. 24. Why V belts transmit more power than flat belts. 25. What is the meaning of 6*37 or 6*7 in a rope drive. 26. What do you mean by pinion sprocket and wheel sprocket and which one is used for driving shaft. 27. What is the function of flywheel and why its material is cast iron. 28. Why the leaf springs are laminated as reducing length. 29. What is the function of clutch and is the difference between uniform wear and uniform pressure. 30. Now a days which type of clutches are used in automobiles. 31. Why disc brake is more efficient than mechanical brake. 32. What is the function of bearings and what are the different types. 33. What is bearing characteristics number and bearing modulus. 34. What is the significance of the digits of a rolling contact bearing number 6304? 35. Which type of gear drive is used for perpendicular transmission of power? 36. Why helical gears transmit more power than spur gears. 37. What do you mean by different terms like back lash, pressure angle, circular pitch in a gear drive. 38. Why involute tooth profile is better than cycloid tooth profile? 39. What is interference in gear drive and how to avoid it? 40. What do you mean by law of gearing
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  4. Explain Design for Assembly. How it is different from Design for manufacturing You can answer this question. You can like the best answer. You can share the question You can get updates of new questions on Facebook linkedin twitter & google plus
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  5. What is the function of Governor and how is it different from flywheel 1. You can answer this question 2. You can like the best answer 3. You can share the question...
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  6. What is 'CC' of a bike? How does it matter? 1. You can answer this question. 2. You can like the best answer. 3. You can share the question
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  7. Mechanical Engineering Interview Questions and answers for freshers on design, safety and maintenance. 1) What is an accident ? An accident is a unexpected and unforeseen event which may or may not injury to a person or a machine tool. 2) What are the standard sizes of drawing board as per Indian Standards? As per Indian Standards :1250×900,900×650,650×500,500×350,350×250 sizes are available. 3) What are the functions of a scale ? (a) To measure distance accurately. (b) For making drawing to scale either in full size, reduced size or enlarged size. 4) What is a sketching ? This is freehand expression of the graphic language. 5) What do you mean by First Aid ? First Aid is immediate and temporary care given to a person who affected accidental injury or a sudden illness before the arrival of doctor. 6) What is a Drawing ? It is a graphical representation of a real thing to define and specify the shape and size of a particular object by means of lines. 7) What is Engineering Drawing ? A drawing which is worked out an engineer for the engineering purpose is known as Engineering Drawing. 8) What are the methods of extinguishing fire ? 1) Starvation. Separating or removing the burning material from the neighbour hood of the fire. 2) Blanketing. Preventing the air flow to the fire. 3) Cooling. Lowering the heat created by burning materials. 9) What are the precautions to be taken to avoid fire ? 1) The buckets along with sand should be placed inside the workshop. 2) Switches and other electrical parts must be made of fireproof material. 3) Carbon dioxide gas should be place at required points in special containers. 4) Fire extinguishers of suitable type should be placed at accessible places.\ 10) What safety precautions should be observed while working in the workshop ? 1) Keep shop floor clean, free from oil and other slippery materials. 2) Wear proper dress and avoid loose clothing and loose hair. 3) Wear shoes and avoid chapels. 4) Avoid playing, loose talk and funning inside the shop floor. 5) Keep good housekeeping and put all unnecessary items and rejected items in scrap box. 6) Learn everything about the machine before starting and clear all the doubts. 7) Keep a safe distance from rotating and sliding parts. 8) Never store inflammable materials inside or around the shop. 9) Never play with electricity, fire, parts with sharp edge etc. 10) Keep fire buckets and extinguishers ready for use.
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  8. The efficiency of diesel engine cycle increases with.. 1. You can answer this question 2. You can like the best answer 3. You can share the question...
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  9. What is the difference between Finite Element Analysis (FEA) and Computational Fluid Dynamics (CFD) based on their computing methods ?
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  10. What is CRDI technology in Diesel engine and how it's work? 1. You can answer this question. 2. You can like the best answer. 3. You can share the question
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  11. Why diesel Engine don't have spark plug? 1. You can answer this question. 2. You can like the best answer. 3. You can share the question
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  12. What is the difference between design and drafting ? Explain with example..
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  13. What type of joint is used to connect two rods subjected to a) tensile loads only and tensile or compressive loads? 1. You can answer this question 2. You can like the best answer 3. You can share the question.
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  14. State difference between AnitiFriction Bearing and Journal Bearing? 1. You can answer this question 2. You can like the best answer 3. You can share the question...
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  15. Twenty One Rules for Tech Writing Introduction One of the things that has surprised me about the readers of ME Forum is the number of folk who want to publish technical papers. When I was an undergraduate (a very, very long time ago), publishing papers was the farthest thing from my mind. I knew that publishing was a concern for some of the faculty, but it was certainly no concern of mine! To my even greater amazement, most of those desiring to write want to write in English, even though this is not their mother-tongue. I presume that this is a natural consequence of the fact that English has come to dominate the technical literature world-wide. That is a good thing for me (I only speak one language), but I would think it must be a daunting prospect for many of you. I have great respect for anyone who would undertake to write a technical paper in a foreign language; it is quite enough of a challenge in a language that I know pretty well. But perhaps it is not so much “foreign” as it is simply a “second language,” for those of you that know multiple languages. Either way, I am impressed that you would tackle this difficult undertaking at this point in your lives. The purpose of this article is an attempt to help those of you who wish to publish, particularly technical publications. Most of what I have to say can be applied to anything you write, comments about such matters as organization, for example. Other parts of this article apply specifically to publication in technical journals, so you must use my suggestions with understand as to where they apply and where they do not. I am organizing this article in two main parts. The first part I have labeled as Philosophy, meaning that it provides some guiding principles to be kept in mind about the way you construct your paper. The second part is labeled Mechanics and refers to details about actual construction of the paper. You will find that both of these are important. I have been reviewing papers for many years now for ASME, SAE, Journal of Mechanism and Machine Theory, and others, and I can tell you with certainty, that many papers fail on some of the most mundane items discussed here. These things matter, and if you want your paper to be accepted, you will need to pay attention to them all. Philosophy 1. Have something interesting to say. There is simply no point to attempting to write a paper on an uninteresting topic, one that does not interest you, the writer, nor the reader. There are times when it is necessary to report information that is less than fascinating, but as the writer, you should seek to find what there is about this information that is interesting and/or important to the reader and point that out. You should never choose to write on a topic where you really do not know what you are talking about; it just will not work! 2. Identify your reader. In most cases, you will not know exactly who the reader is going to be, but you should have some pretty clear ideas about him nevertheless. You will be making definite assumptions about the reader (it may be helpful to go so far as to write these out), about his background and preparation for what you are going to present. Are you writing for a broad, general audience with a limited technical background, or are you writing for someone who is a specialist in the field and perhaps has even more background than you do? The assumptions you make about the reader will have a major impact on what you say and how you say it, so it is necessary to be rather definite about the capabilities of the reader. 3. Identify your publisher. When you write, you need to keep in mind who will be publishing your work. Most established publishers have very definite requirements regarding style, page layouts, footnote/endnote requirements, and a host of other matters. Many journals will publish in each issue a short section with a title like “Information for Authors,” and today this will usually lead a link for a URL where you will find pages and pages of detailed requirements. It is better by far to be aware of these requirements before you begin writing rather than having to do major re-writing simply to meet the publisher’s requirements. 4. Organize your story in a logical form. This is often not the way things came first to you, but it is necessary to make things easy for the reader. Think about the easiest possible way to explain your subject to a reader, the sequencing of information that will enable him to most easily understand the whole topic. This will help you to keep your paper concise and focused. 5. Provide any necessary background. This is often done in an Introduction where you survey related previous work so that someone not intimately acquainted with the field can still follow your work. Depending upon the nature of the publication (journal article, technical report, lab report, etc.), a bit of basic review may be appropriate in some situations. 6. Use correct terminology. Terms such as axial, radial, height, width, length, vertical, horizontal, cylindrical, conical, spherical, etc. have rather specific universal meanings. Be sure to describe carefully the orientation of dimension, and other similar matters that are often essential for a clear understanding. Consider the four words: depth, height, width, length. What directions are associated with each? Height is usually vertical, that is aligned with the local gravity vector. The length of something is usually the longest dimension, assuming that this dimension is horizontal, but what happens if it is not horizontal? The word depth is sometimes associated with a vertical distance, such as the water depth, but it is also associated with a horizontal distance measured away from the observer. The ambiguity of these words means that they must be used with great care. Often it is necessary to say something like, “The depth of the hole, measured in the horizontal plane, is ...” or “The width is 42 mm, as shown on the drawing.” 7. Use consistent terminology throughout. If you call something a brick at the beginning, then it must be called a brick throughout. If you start off talking about the engine, do not switch to talking about the motor. The exception to this occurs when you use a common place term to introduce an idea before giving the technically correct term. Consider for example, “The longest edge of a right triangle is called the hypotenuse.” The common term in this example is “longest edge,” but the technically correct term is “hypotenuse.” 8. Use figures, but use them sparingly. Figures can add a lot of interest to your publication, as well as conveying much information in a simple, easy to understand form. But remember that they are there to inform, to carry information from you to the reader, not simply to look pretty. They take up a lot of space, so they must convey a lot of information. On the other hand, they must not be too cluttered, with text too small to read. Labels with leader lines can help in many cases. 9. Always write a conclusion. The conclusion is important to solidify in the mind of the reader what it is that he has just read. When you write your final conclusion, be sure that your text supports everything that you are concluding and that you have told the whole story. 10. Don’t make you paper too long. Most journals impose a limit of 8 pages, including figures and references, so be concise. There are exceptions, journals that allow longer papers, but the best ones generally have a firm limit. If a paper becomes too long, the reader is very likely to loose interest before finishing, in which case, you have not reached the reader with your information and he has wasted his time. Mechanics 11. Be precise in the use of words. Don’t describe everything as “efficient,” when you really mean “more effective,” “faster” “less expensive,” “more aesthetic,” etc. The bigger your vocabulary is, the easier this will be. Avoid “engineer–speak,” that is, the sort of slang that engineers often use on the job, such terms as “down-force,” “up-draft,” “bhp,” “mip,” “CG,” “cross-over,” etc. (Does everyone know that the CM and the CG are usually the same location, although not always? Giving the whole term makes clear which you mean.) If you think they are necessary, then you must define them in the text. In this same vein, for technical publications it is never acceptable to use the abbreviated form that have become popular with instant messaging, texting, Twitter, etc. I am speaking about such things as “u r” for “you are,” “b4” for “before,” and similar extreme contractions of words. 12. Number all figures, and provide a title. In so far as possible, all figures should be uniform in style. Think twice about the use of color. It looks pretty when well reproduced, but will it always do so? Multi-color figures on a black and white copier lose most of their information. For most purposes, black lines on a white background are the best idea. 13. Number all pages. This seems obvious, but evidently it is not so to everyone. This helps put the pages in order if they get shuffled, it helps a reviewer refer to specific items, and it helps a reader to locate information given in a citation. 14. Number all equations. Again, this seems obvious, but not so to everyone. Use conventional symbols wherever possible (Greek rho for mass density, W for weight, m for mass, v for velocity, etc.) For journal publication, do not show substitutions of numeric values into an equation. Instead, solve the equation in symbols and then show the final numeric result. There may be an exception when for a professional report (such as a stress analysis for a client), you may need to show the substitution. 15. Provide section and subsection heads. This helps to give structure to your paper, conveying the logic of your presentation. Also, it suggests to the reader where to look for particular information. 16. Start a new paragraph with each new idea. The basic purpose of a paragraph is to present one, and only one, idea. This is true even for summary paragraphs where the new idea is the interrelatedness of several ideas presented previously. Single sentence paragraphs are to be avoided. 17. Use spell-check. With all the word processing capability available today, almost all of it including a spell checking feature, there is absolutely no excuse for misspelled words. Now spell-check will not check the logic of your sentences, so the simple fact that spell-check did not flag anything does not mean that everything is correct. But if spell-check does flag a word, you must correct it. 18. Punctuate and capitalize correctly. Be sure to single space after a period at the end of every sentence. When using a hyphen to break a word, do not include a space. Punctuate consistently throughout, with the publisher’s rules as your main guide. Above all, be consistent. It looks terrible to see a space on one side of a hyphen and not on the other 19. Use consistent units throughout, usually SI. This would seem to be obvious, but it is not so to everyone. Most of your work should be formulated in such a way that it is units-free, that is, so that it may be used with any consistent system of units. But when you are reporting numerical results, you will have to use units (unless you use dimension-less ratios which are not entirely satisfactory). 20. Use abbreviations correctly. If you want to use an abbreviation, such as BWR for Boiling Water Reactor, the whole thing must be spelled out the first time, with the abbreviation immediately following in parentheses. Thus, we might say, “Westinghouse provided the Boiling Water Reactor (BWR) for the installation.” Thereafter, use BWR consistently, except at the beginning of a sentence (do not start with an abbreviation). 21. Proof-read, proof-read, proof-read! Putting the words into the computer is only the beginning of writing a paper, definitely not the end. It is necessary to proof read, looking for many different potential problems. Does every sentence make sense and say what you intended for it to say? Is your explanation complete, or are there gaps in it? Is the punctuation and capitalization all correct? Have you followed the publisher’s guidelines for format, style, equation numbering, etc.? When you have read it and re-read it many times, to the point that you think it is perfect, then get someone else to proof-read it also for you. The failure to adequately proof-read is one of the most common of failings, and it reflects very badly on the author. It says that the author did not think that this article was worth making perfect, which makes the reader wonder why he should bother with it at all? Conclusion Following these rules does not assure that your paper will be accepted by one of the leading journals of the world, but failure to follow them virtually assures that your paper will fail. The whole idea of writing a paper is to communicate something to a reader, and these rules are largely about steps that you, the author, can take to facilitate that communication. If what you say is not interesting or is unclear, then there will be no communication. These rules are all about clarity and ease of communication.
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