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  • Osama Khayal
    In its triennial report, the International Ergonomics Association (IEA, 2000) defined ergonomics as the scientific discipline that deals with understanding the interaction between humans and other elements of a socio-technical system. In this definition, ergonomics is the profession that applies theory, principles, data and design methods to optimize human well-being and the overall performance of a system. It is in particular responsible for the design and evaluation of tasks, jobs, products, environments and systems to make them compatible with the abilities, needs and limitations of people.
    The word "Ergonomics" comes from the Greek "Ergon" meaning work and "Nomos" which means law. Therefore, etymologically, this is the science of work. The term has been used historically in the European tradition. In the American tradition one finds the term "Human Factor Engineering" to refer to the same issues, so both terms can be now considered as synonyms and are used interchangeably. The latter is evidenced by the fact that the "Human Factor Society”, founded in Tulsa (Oklahoma) in 1957, is now called the "Human Factor and Ergonomics Society” (HFES). Another term which is often used in the same context is “Engineering psychology” (Wickens & Hollands, 2000).
    The early precursors of the new discipline could be set around the time of the World War I. They had their background in the pioneering studies of Frederic Bartlett (1886-1969), Hugo Munsterberg (1863-1916) and Frederick Winslow Taylor (1856- 1915) on applied psychology and industrial management. The design of new machines (for example, the first cars or tanks) revealed the importance of taking into account the characteristics of people who should operate them. It was found that many people had difficulties to operate with more complex machines, especially with warplanes. This led the army to recruited psychologists who were assigned the task of developing and administering tests to select soldiers and to assign them to different tasks. These applied psychologists first human factors laboratories that continued their work after the war ended. But it was the World War II which provided the final impetus for the establishment of ergonomics as a discipline with industrial and academic recognition. Moreover, this war involved an enormous amount of people and artefacts, many of them newly created, such as radar, which made the idea of selecting a few special individuals to use previously designed artefacts unworkable. The idea that emerged and has had an enormous impact on the development of the discipline was that the devices should be designed by taking into account characteristics of human beings who will use them, and not adapted to people once they are designed.
    In Europe, the focus of ergonomics is to be found in industry and it has been linked to an interest in improving worker performance and satisfaction. The discipline began with an emphasis on the design of equipment and workplaces although in principle themes were related to biological, rather than to the psychological aspects. In this way, studies began on anthropometry, work medicine, architecture, lighting, etc. Back in the 1980s, the Europeans ergonomists began to worry largely about advanced psychological aspects and the "European Association of Cognitive Ergonomics" (EACE) emerged leading to a confluence of interests with human factors and cognitive science professionals in the other side of the Atlantic.
    The definition of ergonomics is extended today to all human activities in which artefacts are implemented. Ergonomists (with many applied psychologists among them) are in a permanent search for comprehensive approaches in which physical, cognitive, social and environmental aspects of human activities can be considered. Although ergonomists often work on different economic sectors or particular tasks, these application domains are constantly evolving, creating new ones and changing the perspective of the old ones. Accordingly, one can recognize today four main domains of expertise crucial for investigating interaction between humans and socio-technical systems.
    Human Factors and Ergonomics.pdf

    Osama Khayal
    The various methods described below have been developed to reduce the resin content of the final product. As a rule of thumb, hand lay-up results in a product containing 60% resin and 40% fiber, whereas vacuum infusion gives a final product with 40% resin and 60% fiber content. The strength of the product is greatly dependent on this ratio.
    Polymer Matrix Composites (PMCs) are very popular due to their low cost and simple fabrication methods. Use of non-reinforced polymers as structure materials is limited by low level of their mechanical properties, namely strength, modulus, and impact resistance. Reinforcement of polymers by strong fibrous network permits fabrication of PMCs, which is characterized: high specific strength, high specific stiffness, high fracture resistance, good abrasion resistance, good impact resistance, good corrosion resistance, good fatigue resistance and Low cost.
    ADVANCEMENTS IN POLYMER COMPOSITE STRUCTURES.pdf

    Osama Khayal
    One of the clearest ways to delineate a discipline is by its unique technology. At its recent workshop, the HFES Strategic Planning Task Force noted, as have others internationally, that the technology of human factors/ergonomics is human-system interface technology. Thus, the discipline of human factors can be defined as the development and application of human-system interface technology.
    Human-system interface technology deals with the interfaces between humans and the other system components, including hardware, software, environments, jobs, and organizational structures and processes. Like the technology of other design-related disciplines, it includes specifications, guidelines, methods, and tools. As noted by the Strategic Planning Task Force, we use our discipline’s technology for improving the quality of life, including health, safety, comfort, usability, and productivity. As a science we study human capabilities, limitations, and other characteristics for the purpose of developing human-system interface technology. As a practice, we apply human-system interface technology to the analysis, design, evaluation, standardization, and control of systems. It is this technology that clearly defines us as a unique, stand-alone discipline, that identifies who we are, what we do, and what we offer for the betterment of society.
    Although they may come from a variety of professional backgrounds, such as psychology, engineering, safety, the rehabilitation professions, or medicine, it is their professional education and training in human-system interface technology that qualifies persons as human factors/ergonomics professionals. Indeed, the discipline needs both the breadth and richness of these professional backgrounds as well as the education and training in the unique technology of human factors/ergonomics.
    Human factors/ergonomics professionals have long recognized the tremendous potential of our discipline for improving people’s health, safety, and comfort and both human and system productivity. Indeed, through the application of our unique human-system interface technology, we have the potential to truly make a difference in the quality of life for virtually all peoples on this globe. In fact, I know of no profession where so small a group of professionals has such tremendous potential for truly making a difference.
    In light of our potential, why is it, then, that more organizations, with their strong need to obtain employee commitment, reduce expenses, and increase productivity, are not banging down our doors for help, or creating human factors/ergonomics positions far beyond our capacity to fill them? Why is it that federal and state agencies are not pushing for legislation to ensure that human factors/ ergonomics factors are systematically considered in the design of products for human use and work environments for employees? Why is it that both industry associations and members of Congress sometimes view us as simply adding an additional expense burden and, thus, increasing the costs of production and thereby decreasing competitiveness? In response to these questions, from my experience, at least four contributing reasons immediately come to mind.
    First, some of these individuals and organizations have been exposed to bad ergonomics – or what, in a recent article on this topic, Ian Chong (1996) labels “voodoo ergonomics” – either in the form of products or work environments that are professed to be ergonomically designed but are not, or in which the so-called ergonomics was done by incompetent persons. This, indeed, is a concern, particularly when persons lacking professional training pass themselves off as ergonomists or human factors professionals or tout their services as a panacea for almost anything. It is one of the major reasons that both establishing educational standards for professional education in human factors/ergonomics and professional certification have become top priority issues for the International Ergonomics Association and, indeed, for many national human factors/ergonomics societies and governmental groups, such as the European Union.
    Another reason, well known to us, is that “everyone is an operator” (Mallett, 1995). Everyone “operates” systems on a daily basis, such as an automobile, computer, television, and telephone; thus, it is very easy to naively assume from our operator experience that human factors is nothing more than “common sense.” Most experienced ergonomists have their own personal list of “common sense” engineering design decisions that have resulted in serious accidents, fatalities, or just plain poor usability. Buy me a beer and I’ll be glad to tell you some of my personal ergonomics “war stories.” I also would refer you to Steve Casey’s book, Set Phasers on Stun (Santa Barbara, CA: Aegean; ISBN 0-9636178-7-7 hc).
    Third, I believe we sometimes expect organizational decision makers to proactively support human factors/ergonomics simply because it is the right thing to do. Like God, mother, and apple pie, it is hard to argue against doing anything that may better the human condition, and so that alone should be a compelling argument for actively supporting the use of our discipline. In reality, managers have to be able to justify any investment in terms of its concrete benefits to the organization – to the organization’s ability to be competitive and survive. That something “is the right thing to do” is, by itself, an excellent but decidedly insufficient reason for managers actually doing it.
    Finally, and perhaps most important, as a group, we have done a poor job of documenting and advertising the cost-benefits of good ergonomics – of getting the word out that most often, good ergonomics is good economics. In fact, that the ergonomics of economics is the economics of ergonomics.
    As one attempt to rectify this situation, I want to share with you a broad spectrum of ergonomics applications that my predecessor as HFES president, Tom Eggemeier, and I have collected from within the United States and elsewhere, in which the costs and economic benefits were documented.
    CORRELATION BETWEEN ERGONOMICS AND ECONOMICS.pdf

    Osama Khayal
    Hydrodynamic machines may be classified according to the direction of energy transfer (energy added or extracted) or the type of action (rotodynamic or positive displacement machines). Rotodynamic machines (momentum transfer machines) have a rotating part (runner, impeller or rotor) that is able to rotate continuously and freely in the fluid. This motion allows an uninterrupted flow of fluid which promotes a steadier discharge than positive displacement machines. Positive displacement machines have a moving boundary (such as a piston or a diaphragm) whereby fluid is drawn or forced into a finite space. This motion causes an intermittent or fluctuating flow and the flow rate is governed by the magnitude of the finite space of the machine and the frequency with which it is filled and emptied. The term "pump" is used when the fluid is a liquid, however, when the fluid is a gas, terms such as compressors, or fans (or blowers) are used. A compressor is a machine whose primary objective is to increase the pressure of the gas, which is accompanied by an increase in the density of the gas. A fan or blower is a machine whose primary objective is to move the gas. Static pressures remain almost unchanged, and therefore the density of the gas is also not changed.
    MECHANICS OF FLUIDS.pdf

    Krunal Dave
    Classification of Automobiles.
    (A) According to Use
    1.Auto cycle.
    2.Motor cycle.
    3.Car and Jeep.
    4.Buses and Trucks.
    (B) According to capacity
    1.Heavy transport vehicle e.g. Trucks and buses.
    2.Light transport vehicle e.g. Car,Jeep
    (C) According to fuel used
    1.Petrol vehicle e.g. scooter,BIke
    2.Diesel vehicle e.g. Car,Truck,Buses
    3.Gas vehicle e.g. Auto rikshaw 
    4.Solar vehicle e.g. Car.
    (D) According to Wheels
    1.Two wheelers e.g Bike,Scotty
    2.Three Wheelers e.g. Auto Rikshaw
    3.Four Wheelers e.g. Car,Jeep
    4.Six and More Wheel e.g. buses and Heavy Truck
    (E) According to drive
    (i) According to sitting
    1.Left hand drive e.g American vehicle
    2.Right hand drive e.g Indian vehicle
    (ii) Accoring to power
    1.Front wheel drive
    2.Rear wheel drive
    3.All wheel drive
    (F) According to transmission
    1.Conventional type e.g. Gear box
    2.Semi automatic
    3.Fully automatic
    (G) According to suspension system
    1.Conventional : Leaf spring
    2.Independent : Hydraulic shock absorber
    (H) According to engine fitting
    1.Front engine.
    2.Rear engine
    3.Transverse under floor engine e.g Bus engine
    (I) According to body construction
    1.Closed car. e.g Alto 800,Swift
    2.Open car e.g Racing car
    3.Special Car e.g Lemborgini

    Jitendra Sahu
    1.The condition that causes vapour locking in a brake system is
    A. overheating of the fluid due to frequent brake application
    B. overcooling of the brakes during high speed driving
    C. keeping the vehicle without use for an extended period
    D. an excessively high engine speed on a downhill road



    2. The portion of a crankshaft which rests on cylinder block is called main journal.
    A. Yes
    B. No

    3. A baffle plate is fitted inside the oil pan to prevent the oil from splashing when it is subjected to vibration and other movement during vehicle operation.
    A. True
    B. False

    4. The motion of the cam is transferred to the valves through
    A. pistons
    B. rocker arms
    C. camshaft pulley
    D. valve stems

    5. Which of the following symptom is caused as a result of brake disc run out ?
    A. Ineffectiveness of the brakes
    B. Judder during braking
    C. Localized wearing of the brake pads
    D. Rapid wearing of the brake pads

    6. If the engine coolant leaks into the engine oil, then engine oil
    A. appears milky
    B. becomes foamy
    C. turns black
    D. none of these

    7. The function of an alternator in an automobile is to
    A. supply electric power
    B. convert mechanical energy into electrical energy
    C. continually recharge the battery
    D. partly convert engine power into electric power

    8. A clutch is usually designed to transmit maximum torque which is
    A. equal to the maximum engine torque
    B. 80 per cent of the maximum engine torque
    C. 150 per cent of the maximum engine torque
    D. none of these

    9. What type of bearing is used for main bearings and connecting rod bearings ?
    A. Ballbearings
    B. Plain bearings
    C. Needle roller bearing
    D. Taper roller bearing

    10. It is necessary to maintain the valve clearances as they
    A. reduce the resistance to sliding that occurs between the cam and the tappet
    B. allow for lengthening of the valves owing to the heat of combustion
    C. increase the speed at which the valves move up and down
    D. make the crankshaft turn smoothly
     
    Ans- 1 (b) 2 (a) 3 (b) 4 (d) 5(a) 6(b) 7(d) 8 (b) 9(a) 10 (b)

    11. Incorrect steering axis inclination (S.A.I.) causes
    A. tendency to assume toe-out orientation
    B. generation of a braking effect at tight corners
    C. poor recovery of the steering wheel after making a turn
    D. the vehicle to pull to the side of lesser inclination

    12. In a unit type body (frameless body) design, the sheet metal parts are welded together, forming a frame work to which outer skin is attached.
    A. True
    B. False

    13. The torque available at the contact between driving wheels and road is known as
    A. brake effort
    B. tractive effort
    C. clutch effort
    D. none of these

    14. A traction control system (TCS) in automobiles controls the
    A. vibrations on the steering wheel
    B. engine power during acceleration
    C. torque that is transmitted by the tyres to the road surface
    D. stopping distance in case of emergency

    15. In radial tyres
    A. one ply layer runs diagonally one way and another layer runs diagonally the other way
    B. all plies run parallel to one another and vertical to tyre bead
    C. inner tubes are always used
    D. none of these

    16. The oil pump is driven by the
    A. camshaft
    B. alternator shaft
    C. crankshaft via drive belt
    D. crankshaft directly

    17. In a spark plug, when the temperature of the central electrode exceeds a certain temperature, any carbon that has adhered will be burnt off, and the temperature at which this burning off carbon starts is referred to as the self cleaning temperature.
    A. Correct
    B. Incorrect

    18. The flywheel and the pressure plate bind the clutch disc between them so that the engine and the transmission can be engaged.
    A. Yes
    B. No

    19. The vehicle ride will be comfortable if
    A. unsprung mass is kept minimum
    B. sprang mass is kept minimum
    C. vehicle mass is kept minimum
    D. all of these

    20. The main function of intake manifold is that it
    A. promotes the mixture of air and fuel
    B. reduces intake noise
    C. cools the intake air to a suitable temperature
    D. distributes intake air equally to the cylinders

    21. Positive camber is used to compensate for wheels tilting inward due to the weight of the vehicle.
    A. Yes
    B. No

    22. In automobiles G.V.W. refers to
    A. gross vehicle width
    B. gross vehicle weight
    C. gross vehicle wheel base
    D. gross vehicle wheel track

    23. The firing order for an in-line four cylinder I.C. engine is
    A. 1-2-3-4 B. 1-3-4-2
    C. 1-2-4-3 D. 1-3-2-4

    24. In a ventilated disc brake,
    A. a duct directs air towards the caliper for cooling while the vehicle is moving
    B. caliper is covered with cooling fins
    C. disc contains many small holes for optimum cooling performance
    D. disc contains radial vanes between its rubbing surfaces for optimum cooling performance

    25. The effect of having excess camber is
    A. excessive steering alignment torque
    B. hard steering
    C. too much traction
    D. uneven tyre wear
    The answers for the above questions is available in the link given below and you will get even more interesting technical questions related to automobile engg...
    https://www.indiabix.com/mechanical-engineering/automobile-engineering/096008



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