Sunday, 16 August 2015

List of basic terms for Mechanical Engineering

1. Torque or Turning Force
2. Couple
3. Moment
4. Stress
5. Strain
6. Spring
7. Specific Weight
8. Specific Volume
9. Specific Gravity
10. Specific Heat
11. Viscosity
12. Buoyancy
13. Discharge of Fluid
14. Bernoulli's Equation
15. Device for Fluid
16. Mach Number
17. Hydraulic Machine
18. Draft Tube
19. Thermodynamics Law-
  • zeroth law
  • First law
  • second law
20. Entropy
21. calorific value of fuel
22. Boiler/Steam Generator
23. Superheater
24. Air Preheater
25. Boiler Draught
26. Nozzle
27. Scavenging
28. Supercharging
29. Turbocharging
30. Governor
31. Flywheel
32. Rating of fuel-
S.I. engine
C.I. engine
33. Stoichiometric Mixture/ Stoichiometric Ratio
34. Heat Transfer
35. Thermal Conductivity
36. Heat Exchanger
37. Refrigeration
38. 1 tonne Refrigeration
39. Humidification
40. De humidification
41. Gear Train
42. Gyroscopic Couple
43. Heat Treatment
44. Ferrous-Metal
45. Non-ferrous metal
46. Allowance
47. Tolerance
48. Clearance
49. Stiffness
50. Toughness
51. Fatigue
52. Nuclear Fission
53. Nuclear Fusion
54. Welding
55. Machine Tool
56. Cutting Tool
57. Indexing
58. Jig
59. Fixture
Details
Torque or Turning Force: It is the total amount of force which is required to create acceleration on moving substance.
Couple: Two forces those acts on equally,parallely & oppositely on two separate points of same material.
Moment: It is the amount of moving effect which is gained for action of turning force.
Stress: It is the force that can prevent equal & opposite force. That means, it is the preventing force.  If one force acts on outside of a material, then a reactive force automatically acts to protest that force. The amount of reactive force per unit area is called stress. e.g. Tensile Stress, Compressive Stress, Thermal Stress.
Strain: If a force acts on a substance, then in that case if the substance would deform. Then the amount of deformation per unit length of that substance is called strain.
Spring: It is one type of device which is being distorted under certain amount of load & also can also go to its original face after the removal of that load. Its function:
  • To store energy.
  • To absorb energy.
  • To control motion of two elements.
Stiffness: Load per unit deflection. The amount of load required to resist the deflection.
Specific Weight: Weight per unit volume of the fluid.
Specific Volume: Volume per unit mass of the fluid.
Specific Gravity: It is the ratio of specific weight of required substance to specific weight of pure water at 4 degree centigrade temperature.
Specific heat: The amount of heat required to increase 1 unit temperature of 1 unit mass.
Viscosity:
  • Dynamic Viscosity: The amount of resistance of one layer of fluid over other layer of fluid.
  • Kinematic Viscosity: It is the ratio of dynamic viscosity to density.
Buoyancy: When a body is immersed in a liquid, it is lifted up by a force equal to weight of liquid displaced by the body. The tendency of liquid to lift up an immersed body is buoyancy. The upward thrust of liquid to lift up the body is called buoyancy force.
Bernoulli's Equation:
P/γ +V²/2g +Z = Constant
Where, P = pressure,V = velocity,Z = Datumn Head
Devices for fluid:
  • Venturimeter: It measures discharge of fluid.
  • Notches : It measures discharge of fluid.
  • Orifice meter: It measures discharge of fluid.
  • Pitot tube : It measures velocity of fluid.
Mach Number: It is the ratio of the velocity of fluid to the velocity of
sound.
M=1 ----------------- Sonic flow
M> (1-6) ----------- Super-Sonic flow
M>6 ---------------- Hyper-Sonic flow
Fluid discharge/Fluid flow: Quantity of fluid flowing per second. (through a section of pipe/ through a section of channel)
Q=AV
where, V= velocity of fluid,A= cross-sectional area of pipe/channel
Note: 1m³ = 1000 L1 cusec = 1 ft³/sec1 ft = 0.3048 m.
Hydraulic Machine:
Turbine,Pump,Compressor etc.
Draft tube:
It attaches with reaction turbine . Its function is to reduce energy loss from reaction turbine & it also reduce pressure at outlet which is must blow the atmospheric pressure.
Themodynamics Law:
  • Zeroth Law
  • First Law of Thermodynamic
  • Second Law of thermodynamic
Zeroth Law: If two body are in thermal equilibrium with a third body then these two body are also in thermal equilibrium with each other.
First Law of Thermodynamics: In a closed system, work deliver to the surrounding is directly proportonal to the heat taken from the surrounding.And also, In a closed system, work done on a system is directly proportonal to the heat deliver to the surrounding.
Second Law of Thermodynamics: It is impossible to make a system or an engine which can change 100 percent input energy to 100 percent output.
Entropy: It is a thermodynamic property.
ds = dq/T
where, ds = change of entropy, dq = change of heat,
T = Temperature.
In adiabatic process, entropy can not change. Actually,lacking or mal-adroitness of tranfering energy of a system is entropy.
Calorific Value of fuel:
It us the total amount of heat obtained from burning 1 kg solid or liquid fuel.
Boiler/Steam
  • Generator: It is a clossed vessel which is made of steel. Its function is to transfer heat to water to generate steam.
  • Economiser: It is a part of boiler. Its function is to heat feed water which is supplied to boiler.
  • Superheater: It is a part of boiler. Its function is to increase temperature of steam into boiler.
  • Air-Preheater: It is a part of boiler. Its funtion is to preheats the air to be supplied to furnace and it recover heat from exhaust gas.
  • Boler Draught: It is an important term for boiler. It is the difference of pressure above and below the fire grate. This  pressure difference have to maintain very carefully inside the bolier. It actually maintaind the rate of steam generation. This depends on rate of fuel burning. Inside the boiler rate of fuel burning is maintained with rate of entry fresh air. If proper amount of  fresh air never entered into the boiler, then proper amount of fuel inside the boiler never be  burnt. So, proper fresh air enters into the boiler only by maintaining boiler draught.
Nozzle: Nozzle is a duct of varying cros-sectional area. Actually, it is a passage of varying cross-sectional area. It converts steam's heat energy into mechanical energy. It is one type of pipe or tube that carrying liquid or gas. Scavenging: It is the process of removing burnt gas from combustion chamber of engine cylinder.
Supercharging: Actually, power output of engine depends on what amount of air enter into the engine through intake manifold. Amount of entry aiy if increased, then must be engine speed will increased. Amount of air  will be increased by increasing inlet air density. The process of increasing inlet air density is supercharging. The device which is used for supercharging is called supercharger.Superchargeris driven by a belt from engine crakshaft. It is installed in intake system. Turbocharging: Turbocharging is similar to the supercharging. But in that case tubocharger is installed in exhaust system whereas supercharger is installed in intake system. Turbocharger is driven by force of exhaust gas. Generally, turbocharger is used for 2-stroke engine by utilizing exhaust energy of the engine, it recovers energy otherwise which would go waste..
Governeor: Its function id to regulate mean speed of engine when there are variation in the load. If load incrases on the engine, then engine's speed must decrease. In that case supply of working fluid have to increase. In the otherway, if load decrease on the engine, then engine' speed must increase. In that case supply of working fluid have to decrease.Governor automatcally, controls the supply of working fluid to the engine with varying load condition.
Flywheel: It is the one of the main parts of the I.C. engine. Its main function id to store energy in the time of working stroke or expansion stroke. And, it releasesenergy to the crankshaft in the time of suction stroke, compression stroke & exhaust stroke. Because, engine has only one power producing stroke.
Rating of fuel:
S.I. Engine:
Octane number. Octane number indicates ability of fuel to resist knock.
C.I. Engine:
Cetane Number. Cetane number indicates ability of ignition of diesel fuel. That means, how much fast ignites diesel fuel.
Stoichiometric ratio: It is the chemically correct air-fuel ratio by volume. By which theoratically sufficient oxygen will be gotten to burn all combustible elements in fuel completely.
Heat Transfer:  It is a science which deals with energy transfer between material bodies as a result of temperature difference.There are three way to heat transfer such as-Conduction Convection  Radiation.
Thermal Conductivity: It is the quantity of heat flows between two parts of solid material by conduction. In this case following consideration will be important fact-
Time------ 1 sec
Area of that solid material-------- 1 m²
Thickness of that solid material------ 1m
Temperature difference between two parts of that material------ 1k
Heat Exchanger: It is one type of device which can transfer heat from one fluid to another fluid. Example- Radiator, intercooler, preheater, condenser, boiler etc.
Refrigeration: It is the process of removing heat from a substance. Actually, extraction of heat from a body whose temperature is already below the temperature of its surroundings.
1 tonne of refrigeration: It is amount of refrigeration effect or cooling effect which is produced by uniform melting of 1 tonne ice in 24 hours from or at 0 degree centigrade or freezing 1 tonne water in 24 hours from or at 0 degree centigrade.
Humidification: It is the addition of moisture to the air without change dry bulb temperatur.
Dehumidification: It is the removal of moisture from the air without change dry bulb temperature.
Gear Train: Meshing of two or more gear. It can transmit power from one shaft to another shaft.
Heat Treatment: Operation involving heating and cooling of a metal in solid state for obtaining desirable condition without being changed chemical composition.Its object- increase hardness of metal.increase quality of metal ( heat, corrosion,wear resistance quality ) improve machinability.
Ferrous Metal:
1. Cast Iron - (2-6.67)%C, Si, Mn, P, S
2. Steel - (0-2)%C
3. Wrought Iron - 99.5% Fe
Non-Ferrous Metal:
1. Brass - (Cu+Zn)
2. Bronze -
(Sn+Cu) ------ Tin Bronze
(Si+Cu) ------- Silicon Bronze
(Al+Cu) ------- Aluminum Bronze
Allowance:
It is the difference between basic dimension of mating parts. That means, minimum clearance between mating parts that can be allowed.
Tolerance: It is the difference between upper limit of dimension. It is also the permissible variation above and below the basic size. That means maximum permissible variation in dimensions.
Clearance: It is the difference in size between mating parts. That means, in that case the outside dimension of the shaft is less than internal dimension of the hole.
Stiffness: It is the ability to resist deformation.
Toughness: It is the property to resist fracture.
Fatigue: When a material is subjected to repeated stress below yield point stress, such type of failure is fatigue failure.
Nuclear Fission: It is a nuclear reaction by which one big nucleous divided into two or more nucleous.
Nuclear Fussion: It is also a nuclear reaction by which one big nucleous will produced by adding two small nucleous.
Welding: It is the process of joining two similar or dissimilar metal by fusion.
Arc Welding -* need D.C current
* produced (6000-7000) Degree Centegrade Temperature
Gas Welding -
* Oxy - acetylene flame join metals
* Oxygen & acetylene gas works
* produced 3200 Degree Centegrade Temperature
Machine Tool: It is the power driven tool. It cut & form all kinds of metal parts.
Example - 1. Lathe2. Drill Press3. Shaper4. Planer5.Grinding6. Miling7. Broaching8. Boring
Cutting Tool: Tool Materials for Cutting Tool:
1. High Carbon Steel
2. High Speed Steel (W+Cr+V)
3. Carbide (W Carbide+Ti Carbide+Co Carbide)
Indexing: It is the method of dividing periphery of job into equal number of division. Actually, it is the process of dividing circular or other shape of workpiece into equal space, division or angle.
Jig: It is one type of device which hold & locate workpiece and also guide & control cutting tool. It
uses in drilling, reaming and tapping.
Fixture: It is one type of device which hold and locate workpiece. It uses in miling, grinding, planning & turning.

Friday, 14 August 2015

How to put the bottle full of drink inside the refrigerator to cool so that it cools

Mechanical engineers know How to put the bottle full of drink inside the refrigerator to cool so that it cools faster : horizontally or vertically...
I am always fascinated by the subject Heat Transfer. There are so many cool facts about heat.
HEAT this is something which give me ecstatic feeling. Read on to know the mind-boggling science
behind answer. Treating the bottle full of drink as a thermodynamic closed system.One can readily see, if the bottle needs to be cooled, it needs to release its energy out to the environment so that it cools And the objective is to do this as quickly as possible Natural convective heat transfer plays substantial role in this phenomenon.Rate of natural convection is different for horizontal cylinder and vertical cylinder because of its dependence on effective height or length. If bottle is kept vertical, the effective length is more and if bottle is kept horizontally then the effective height is less. Hence in later case, heat transfer rate from surrounding to bottle is less.

Ultimately we don’t have to release extra energy and it takes less time to cool otherwise as we cool bottle, it gets heated up at faster rate in case of vertically position so time for cooling increases. Actually time required to cool in the vertical position for the drink bottle (if dimensions of axial length is assumed about 5 times that of the diameter) is 50 % longer than that required when the bottle is kept in horizontal position inside the refrigerator. Chill that drink quickly by placing it horizontally inside the fridge. It is just awesome fact which only MechiezZ know, isn't it ?

Successful roadmap a fellow student follow to achieve AIR 22 in GATE-ME 2014

This was the successful road map he followed to achieve AIR 22 in GATE-ME 2014:
(1) ENGINEERING MATHEMATICS
This constitutes 15% of the total marks of the paper. Problems on finding rank of matrix, type of solution (unique, infinitely many etc.), simple integration (using Trapezoidal, Simpson’s 1/3rd rule etc.), Simple formula based Laplace Transforms, simple probability distributions (normal, poisons, binomial distribution , uniform distribution ), directional derivatives, divergence, curl, simple dice problems, limits, simple PDE are all common.
(2) MECHANICS, SOM
This constitutes 10-15 marks of your paper. You can find simple FBD problems (just 1) for finding force, conservation of momentum, block and slope type (average stress and maximum stress for different sections like rectangle ,triangle etc.), Macaulay’s theorem (slope & deflection), one question on thin pressure vessels, problems on various theories of failure , torques, and bending moment calculation, truss.
(3) DESIGN OF M/C ELEMENTS, TOM
This chapter makes up a huge chunk of your marks – 15 to 20! Expect one problem on (Goodman or Soderberg or Gerber Criteria), bearings (life) calculation , torsion of a bar, loading on a plate with bolts, strain energy, S-N curve, degrees of freedom,  output velocity calculation of mechanism, relative velocity approach, Instantaneous Centre Method, clutch power, brake power, belt drive, conceptual questions on D.O.F. of mechanisms, simple gearing ratio problems on spur gears, type of mechanism (based on link lengths), simple spur gear main, quick return mechanism, mobility.
(4) VIBRATIONS
Questions on vibration account for 2-4 marks. You will find questions on simple single D.O.F , finding natural frequencies (underdamped, critically damped, overdamped)
(5) FLUID MECHANICS
This chapter accounts for 5-10 marks. Expect questions on simple & differential piezometer, pressure column height calculation, Reynold’s no. calculation, hydraulic power ,nozzle velocity etc. of turbines, continuity equation, Bernoulli’s law (simple problems), tapered sections, pump parameters (speed, power, discharge), gates(of dams) force calculation, venturimeter , laminar flow.

(6) THERMAL SCIENCE
This is another chapter that accounts for 5-10 marks. Problems asked are usually based on Rankine Cycle, Brayton Cycle, Regeneration in steam cycles, and other cycles, T-S diagrams, P-V diagrams, enthalpy calculations, C.O.P., ŋ, parameters of I.C. engine (power, volume capacity, stroke, ŋ, brake power), DBT(Dry Bulb Temp.), WBT (Wet Bulb Temp.), ŋ relations (otto ,diesel cycles), work done, exit temperature in various stages of cycles , pressure of nozzle, compressor work calculations.
(7) HEAT TRANSFER
5-10 marks are generally allotted to this chapter. Make sure to study convection, conduction, radiation, Efficiency calculation, heat exchanger (parallel & counter flow) outlet temp. calculation, biot number, Prandtl number, LMTD, Heat transfer through slabs, shells,cylinders, condenser, view factor, unsteady cooling.
(8) MANUFACTURING SCIENCE
This is a monster chapter. It accounts for 10-15 marks. Expect formula based problems on machining (milling, drilling, EDM, ECM) machining time, current, tool geometry, punching, blanking, force; conceptual & theoretical questions; orthogonal machining , heat & power required in welding, transformations (rotations, scaling etc.), solidification time, CNC machine G codes and M Codes , sheet metal, various types of fits, clearance calculation, arc welding, cutting time ( ).

(9) INDUSTRIAL ENGINEERING
10-15 of the total marks are usually from this  chapter. Be prepared with forecasting model, CPM, PERT, depreciation, cost (labour, tool grinding cost, waiting cost etc.), P-chart, C-chart, R-chart, X- chart, Time study, EOQ, standard time, demand, Poisson’s arrivals & departures , LPP problems (graphical), simplex method, GO, NO-GO gauges, Machine allocation problems, Sequencing problems , EDD, SPT rule (scheduling) etc.

All the best!

Tips and Strategy for GATE ME

GATE PATTERN
GATE exam is of 100 marks and in mechanical average cut off is between 25 to 30, but may depend on the exam of particular year. there is 70 marks for the all technical part of mechanical side which consist of core mechanical subjects and other part consist of 15 marks engineering mathematics plus 15 marks for aptitude and English.
Heat transfer, Thermodynamics, Fluid Mechanics and Machines, Strength of materials, Theory of Machines, Production Technology, Power plant, RAC and Machine Design, IC engines Engineering mathematics English and Reasoning and Aptitude for me preparing time is less so i left machine design and RAC, but i suggest you to not to leave any of these subjects.i explain how to make this simple.
Strategy
Firstly cover Thermodynamics completely with last 10 years gate papers and after that when you are through with the subject then its time for heat transfer and IC engine cycles i.e. Otto, and diesel cycles.With Thermodynamics it is easy for you to cover heat transfer and understand it easily.
Now when you are done with these subjects then its time for Fluid and power plant subjects, comparatively fluid syllabus is more than power plant, power plant only includes vapour power cycle and steam power cycle. So these are the very important subjects
Now the most important subject according to me is Production. Technology, all last year exam gives you an idea how important is this. In GATE 2013 it consist of 16 marks out of 70. so it makes you feel that how important is this subject, so give sufficient time to this subject to justify its importance. In production technology metal cutting, casting, forming is very very important.
Now subjects Theory of Machines and Strength of Materials have equal importance. Always 7 to 8 marks is expected from these subjects.
Machine design and RAC consist of less marks but never underestimate these subjects as of their importance.
According to me at least 20 to 25 days are requires for the practise after your preparation of all subjects.other subject i.e. maths, Eng. and aptitude also require time for the practise.

HOW TO MAKE PREPARATION SIMPLE Now you are thinking all these subjects done at a time is very difficult to remember. so here the some ways to how to do this:
1. firstly you prepare thermal subjects i.e. Thermodynamics, heat transfer, IC engines.
2. then start fluid along with practise of previous subjects.
3. at the middle of fluid start production and
4. when fluid ends along with of production start some 1 or 2 hour practise of maths, and aptitude.
5. when you all are done then try to give some tests so that to increase your speed.
6. doing all your practise set a time alarm near to you so that every time you can increase your speed.
7. now for machine design and rac if more time is there then go completely through these subjects
8. but if time is not there then try to see last year papers what is they are asking in these subjects and make Strong that topics.
9. 20 to 25 days of complete practise is must.
10. try to maintain daily 8 to 10 hours, is you are able to give more that is up to you soon

I have already posted information regarding gate exam [check on Gate Tab] and list of important gate topics. you can ask for any of your doubt.
keep preparing....

Monday, 10 August 2015

11 Habits for effective Teaching

By Carrie Lam , Academic Director, Teacher & Workshop Leader, Canada
I really appreciate teachers who are truly passionate about teaching. The teacher who wants to be an  inspiration to others. The teacher who is happy with his/her job at all times. The teacher that every other child in the school would love to have. The teacher that kids remember for the rest of their lives. Are you that teacher? Read on and learn 11 effective habits of an effective teacher.
1. ENJOYS TEACHING.
Teaching is meant to be a very enjoyable and rewarding career field (although demanding and exhausting at times!). You should only become a teacher if you love children and intend on caring for them with your heart. You cannot expect the kids to have fun if you are not having fun with them! If  you only read the instructions out of a textbook, it's ineffective. Instead, make your lessons come alive by making it as interactive and engaging as possible. Let your passion for teaching shine through each and everyday. Enjoy every teaching moment to the fullest.
2. MAKES A DIFFERENCE.
There is a saying, "With great power, comes great responsibility". As a teacher, you need to be aware and remember the great responsibility that comes with your profession. One of your goals ought to be: Make a difference in their lives. How? Make them feel special, safe and secure when they are in your classroom. Be the positive influence in their lives. Why? You never know what your students went through before entering your classroom on a particular day or what conditions they are going home to after your class. So, just in case they are not getting enough support from home, at least you
will make a difference and provide that to them.
3. SPREADS POSITIVITY.
Bring positive energy into the classroom every single day. You have a beautiful smile so don't forget to flash it as much as possible throughout the day. I know that you face battles of your own in your personal life but once you enter that classroom, you should leave all of it behind before you step foot in the door. Your students deserve more than for you to take your frustration out on them. No matter how you are feeling, how much sleep you've gotten or how frustrated you are, never let that show. Even if you are having a bad day, learn to put on a mask in front of the students and let them think of you as a superhero (it will make your day too)! Be someone who is always positive, happy and smiling. Always remember that positive energy is contagious and it is up to you to spread it. Don't let other people's negativity bring you down with them.
4. GETS PERSONAL.
This is the fun part and absolutely important for being an effective teacher! Get to know your students and their interests so that you can find ways to connect with them. Don't forget to also tell them about yours! Also, it is important to get to know their learning styles so that you can cater to each of them as an individual. In addition, make an effort to get to know their parents as well. Speaking to the parents should not be looked at as an obligation but rather, an honor. In the beginning of the school year, make it known that they can come to you about anything at anytime of the year. In addition, try to get to know your colleagues on a personal level as well. You will be much happier if you can find a strong support network in and outside of school.
5. GIVES 100%.
Whether you are delivering a lesson, writing report cards or offering support to a colleague - give  100%. Do your job for the love of teaching and not because you feel obligated to do it. Do it for self-growth. Do it to inspire others. Do it so that your students will get the most out of what you are teaching them. Give 100% for yourself, students, parents, school and everyone who believes in you. Never give up and try your best - that's all that you can do. (That's what I tell the kids anyway!)
6. STAYS ORGANIZED.
Never fall behind on the marking or filing of students' work. Try your best to be on top of it and not let the pile grow past your head! It will save you a lot of time in the long run. It is also important to keep an organized planner and plan ahead! The likelihood of last minute lesson plans being effective are slim. Lastly, keep a journal handy and jot down your ideas as soon as an inspired idea forms in your mind. Then, make a plan to put those ideas in action.
7. IS OPEN-MINDED.
As a teacher, there are going to be times where you will be observed formally or informally (that's also why you should give 100% at all times). You are constantly being evaluated and criticized by  our boss, teachers, parents and even children. Instead of feeling bitter when somebody has something to say about your teaching, be open-minded when receiving constructive criticism and form a plan of
action. Prove that you are the effective teacher that you want to be. Nobody is perfect and there is always room for improvement. Sometimes, others see what you fail to see.
8. HAS STANDARDS.
Create standards for your students and for yourself. From the beginning, make sure that they know what is acceptable versus what isn't. For example, remind the students how you would like work to be completed. Are you the teacher who wants your students to try their best and hand in their best and
neatest work? Or are you the teacher who couldn't care less? Now remember, you can only expect a lot if you give a lot. As the saying goes, "Practice what you preach".
9. FINDS INSPIRATION.
An effective teacher is one who is creative but that doesn't mean that you have to create everything from scratch! Find inspiration from as many sources as you can. Whether it comes from books, education, Pinterest, YouTube, Facebook, blogs, TpT or what have you, keep finding it!
10. EMBRACES CHANGE.
In life, things don't always go according to plan. This is particularly true when it comes to teaching. Be flexible and go with the flow when change occurs. An effective teacher does not complain about changes when a new principal arrives. They do not feel the need to mention how good they had it at their last school or with their last group of students  compared to their current circumstances. Instead of stressing about change, embrace it with both hands and show that you are capable of hitting every
curve ball that comes your way!
11. CREATES REFLECTIONS.
An effective teacher reflects on their teaching to evolve as a teacher. Think about what went well and what you would do differently next time. You need to remember that we all have "failed" lessons from time to time. Instead of looking at it as a failure, think about it as a lesson and learn from it. As teachers, your education and learning is ongoing. There is always more to learn and know about in order to strengthen your teaching skills. Keep reflecting on your work and educating yourself on what you find are your "weaknesses" as we all have them! The most important part is recognizing them and being able to work on them to improve your teaching skills. There are, indeed, several other habits that make an effective teacher but these are the ones that I find most important. Many other character traits can be tied into these ones as well.

LAST WORD: There is always something positive to be found in every situation but it is up to you to find it. Keep your head up and teach happily for the love of education!

Thursday, 6 August 2015

Most study engineering due to parental push:Survey

CHENNAI: Around 65% of students enroll in engineering courses out of parental compulsion and many had got admission despite low scores in physics and maths which are key subjects for engineering to determine aptitude. These are the findings of a study conducted by M-tutor, a private company that develops supplementing tools for educational learning.
The study conducted across nearly 100 colleges in various states found that such students who had enrolled in engineering courses due to parental  compulsion displayed a lack of interest in the field and did not have any long-term career goals. Such students experienced high peer pressure right from day one, it found.
K V Nandita, a telecom engineering student, said that she had initially failed in Maths in her plus-two exam and had to re-appear for the exam before applying for an engineering seat. "My marks were not great but since nearly everyone in my class was taking up engineering, I wanted to get into engineering too," she said. "We observed that in such cases, the parents also put pressure on institutions for placements. This in turn pressurizes the institutions to focus on a quantitative rather than a qualitative approach in their academic processes," said V Sundaramoorthy, managing director of M-tutor.
The study also discerned a change in patterns of learning among students over the last decade. This included their focus being affected due to high levels of distortion because of exposure to digital mediums. The study also found that their ability to grasp concepts during a a classroom session and to take down notes had weakened. Most of them were hesitant to even express this shortcoming to their own classmates, it said.
"Learning dynamics have changed from subjective approach to examination approach. There is a lack of scientific tools to monitor the outcome of the learning imbibed by students and their interest in the concepts," said Sundaramoorthy.

Wednesday, 5 August 2015

CAD/CAM COURSES

In general, there are three program options for mechanical CAD students, including certificate, diploma and 2-year degree programs. Certificate programs are frequently two semesters in length and designed to train entry-level mechanical CAD operators. There are also certificate programs that require fewer credits to complete, which are designed for students with engineering backgrounds.

Mechanical CAD diploma programs include a few general education courses along with CAD and engineering design courses.  Associate's degrees in mechanical CAD require an average of 70 credits and include general education, mechanical CAD and other technology courses. An Associate in Applied Science in Mechanical CAD is for students who want to become professional mechanical drafters.
List of Courses
The following courses are commonly offered in mechanical CAD educational programs. Beginning CAD Course This foundation course teaches students to operate CAD software and hardware. Traditional technical drafting skills, including freehand sketching, are reviewed. Basic CAD skills are introduced and used to create 2-dimensional representations. Various software packages, including AutoCAD, are also taught.
Mechanical CAD Course
In this course, instructors introduce CAD techniques for mechanical drafting, building on the skills learned in the beginning CAD course. Mechanical CAD students create detailed engineering drawings using CAD software such as ProE. Industry standards for engineering design, including geometric dimensions and tolerance standards, are incorporated in class work. Computer Graphics for Engineering Course Topics covered in this course include creating 3- dimensional graphical representations of mechanisms. Students use applications such as animation software to view engineering graphics. This is an introductory course completed in the first semester of study in a 2-year program. Manufacturing Materials and Processes Course Properties of various manufacturing materials are surveyed in this course. Processes used to engineer products, such as forming and molding, are also covered. Specific materials studied include metals, plastics and ceramics. This course is a prerequisite for a course in machine design.

Machine Design Course
Students study the function of individual machine components and then design each component using
CAD software. Coursework concentrates on material choice, precision calculations and cost estimates. A portion of the course is focused on the inter connectivity of mechanical elements such as
belts, bearings, cams and shafts, in machine design.

Physics and Materials for Mechanical CAD
Operators Course
In this course, students study the physical properties of materials and material performance under certain stressors. General physics topics such as inertia, stress and torque are reviewed. This course is normally completed near the end of a 2-year program. As at the first step I have try to list all the CAD software. If I am missing some software to mention, than surely you can help me by informing me about that CAD, thermal software.
CAD software list
CAD SOFTWARES CO#1
CAD SOFTWARES CO#2
Autodesk
Alibre Design
Autocad electrical
Autodesk Revit
Autodesk Inventor
Auto CAD
Autodesk 3ds Max
Brics cad
CATIA
Creo Parametric / ProEngineer
DraftSight
Femap
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Ansys
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SIMUFACT
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SIMULIA*
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27. vDECC – project management software designed to operate from FEED (Front End Engineering Design).
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34. Free CAD Viewer – view AutoCAD drawings with free DWG/DXF/DWF viewer.
35. SST Systems, Inc. offers software for piping stress, fluid flow and nozzle flexibility analyses.
36. FMEA-Pro is Failure Modes and Effects Analysis software for manufacturers of Automotive, Electronic, Aerospace, Defense and Manufacturing products.
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*Simulia contain multi-physics and Abaqus as its module or you can purchase them separately.

Monday, 3 August 2015

123 TOP D.C. Motors - Electrical Engineering Multiple Choice Questions and Answers

Latest D.C. Motors Interview Questions and Answers List

1. No-load speed of which of the following motor will
be highest ?
(a) Shunt motor
(b) Series motor
(c) Cumulative compound motor
(d) Differentiate compound motor
Ans: b
2. The direction of rotation of a D.C. series motor
can be changed by
(a) interchanging supply terminals
(b) interchanging field terminals
(c) either of (a) and (b) above
(d) None of the above
Ans: b
3. Which of the following application requires high
starting torque ?
(a) Lathe machine
(b) Centrifugal pump
(c) Locomotive
(d) Air blower
Ans: c
4. If a D.C. motor is to be selected for conveyors,
which rriotor would be preferred ?
(a) Series motor
(b) Shunt motor
(c) Differentially compound motor
(d) Cumulative compound motor
Ans: a
5. Which D.C. motor will be preferred for machine
tools ?
(a) Series motor
(b) Shunt motor
(c) Cumulative compound motor
(d) Differential compound motor
Ans: b
6. Differentially compound D.C. motors can find
applications requiring
(a) high starting torque
(b) low starting torque
(c) variable speed
(d) frequent on-off cycles
Ans: b
7. Which D.C. motor is preferred for elevators ?
(a) Shunt motor
(b) Series motor
(c) Differential compound motor
(d) Cumulative compound motor
Ans: d
8. According to Fleming's left-hand rule, when the
forefinger points in the direction of the field or flux,
the middle finger will point in the direction of
(a) current in the conductor aovtaat of conductor
(c) resultant force on conductor
(d) none of the above
Ans: a
9. If the field of a D.C. shunt motor gets opened
while motor is running
(a) the speed of motor will be reduced %
(b) the armature current will reduce
(c)  the motor will attain dangerously high speed 1
(d) the motor will continue to nuvat constant speed
Ans: c
10. Starters are used with D.C. motors because
(a) these motors have high starting torque
(b) these motors are not self-starting
(c) back e.m.f. of these motors is zero initially
(d) to restrict armature current as there is no back
e.m.f. while starting
Ans: d
11. In D.C.  shunt motors as load is reduced
(a) the speed will increase abruptly
(b) the speed will increase in proportion to reduction
in load
(c) the speed will remain almost/constant
(d) the speed will reduce
Ans: c
12. A D.C. series motor is that which
(a) has its field winding consisting of thick wire and
less turns
(b) has a poor torque
(c) can be started easily without load
(d) has almost constant speed
Ans: a
13. For starting a D.C. motor a starter is required
because
(a) it limits the speed of the motor
(b) it limits the starting current to a safe value
(c) it starts the motor
(d) none of the above
Ans: b
14. The type of D.C. motor used for shears and
punches is
(a) shunt motor
(b) series motor
(c) differential compoutid D.C. motor
(d) cumulative compound D.C. motor
Ans: d
15. If a D.C. motor is connected across the A.C.
supply it will
(a) run at normal speed
(b) not run
(c) run at lower speed
(d) burn due to heat produced in the field winding by
.eddy currents
Ans: d
16. To get the speed of D.C, motor below the normal
without wastage of electrical energy is used.
(a) Ward Leonard control
(b) rheostatic control
(c) any of the above method
(d) none of the above method
Ans: a
17. When two D.C. series motors are connected in
parallel, the resultant speed is
(a) more than the normal speed
(b) loss than the normal speed
(c) normal speed
(d) zero
Ans: c
18. The speed of a D.C. shunt motor more than its
full-load speed can be obtained by
(a) decreasing the field current
(b) increasing the field current
(c) decreasing the armature current
(d) increasing the armature current
Ans: a
19. In a D.C. shunt motor, speed is
(a) independent of armature current
(b) directly proportional to  the armature current
(c) proportional to the square of the current
(d) inversely proportional to the armature current
Ans: a
20. A direct on line starter is used: for starting
motors
(a) up to 5 H.P.
(b) up to 10 H.P.
(c) up to 15 H.P.
(d) up to 20 H.P.
Ans: a
21. What will happen if the back e.m.f. of a D.C.
motor vanishes suddenly?
(a) The motor will stop
(b) The motor will continue to run
(c) The armature may burn
(d) The motor will run noisy
Ans: c
22. In case of D.C. shunt motors the speed is
dependent on back e.m.f. only because
(a) back e.m.f. is equal to armature drop
(b) armature drop is negligible
(c) flux is proportional to armature current
(d) flux is practically constant in D:C. shunt motors
Ans: d
23. In a D.C. shunt motor, under the conditions of
maximum power, the current in the armature will be
(a) almost negligible
(b) rated full-load current
(c) less than full-load current
(d) more than full-load current
Ans: d
24. These days D.C. motors are widely used in
(a) pumping sets
(b) air compressors
(c) electric traction
(d) machine shops
Ans: c
25. By looking at which part of the motor, it can be
easily confirmed that a particular motor is D.C.
motor?
(a) Frame
(b) Shaft
(c) Commutator
(d) Stator
Ans: c
26. In which of the following applications D.C. series
motor is invariably tried?
(a) Starter for a car
(b) Drive for a water pump
(c) Fan motor
(d) Motor operation in A.C. or D.C.
Ans: a
27. In D.C. machines fractional pitch winding is used
(a) to improve cooling
(b) to reduce copper losses
(c) to increase the generated e.m.f.
(d) to reduce the sparking
Ans: d
28. A three point starter is considered suitable for
(a) shunt motors
(b) shunt as well as compound motors
(c) shunt, compound and series motors
(d) all D.C. motors
Ans: b
29. In case-the conditions for maximum power for a
D.C. motor are established, the efficiency of the
motor will be
(a) 100%
(b) around 90%
(c) anywhere between 75% and 90%
(d) less than 50%
Ans: d
30. The ratio of starting torque to full-load torque is
least in case of
(a) series motors
(b) shunt motors
(c) compound motors
(d) none of the above
Ans: b
32. In D.C. motor which of the following can sustain
the maximum temperature rise?
(a) Slip rings
(b) Commutator
(c) Field winding
(d) Armature winding
Ans: c
33. Which of the following law/rule can he used to
determine the direction of rotation of D.C. motor ?
(a) Lenz's law
(b) Faraday's law
(c) Coloumb's law
(d) Fleming's left-hand rule
Ans: d
34. Which of the following load normally needs
starting torque more than the rated torque?
(a) Blowers
(b) Conveyors
(c) Air compressors
(d) Centrifugal pumps
Ans: b
35. The starting resistance of a D.C. motor is
generally
(a) low
(b) around 500 Q
(c) 1000 Q
(d) infinitely large
Ans: a
36. The speed of a D.C. series motor is
(a) proportional to the armature current
(b) proportional to the square of the armature
current
(c) proportional to field current
(d) inversely proportional to the armature current
Ans: d
37. In a D.C. series motor, if the armature current is
reduced by 50%, the torque of the motor will be
equal
to
(a) 100% of the previous value
(b) 50% of the previous value
(c) 25% of the previous value
(d) 10% of the previous value
(e) none of the above
Ans: c
38. The current drawn by the armature of D.C.
motor is directly proportional to
(a) the torque required
(b) the speed of the motor
(c) the voltage across the terminals
(d) none of the above
Ans: a
39. The power mentioned on the name plate of an
electric motor indicates
(a) the power drawn in kW
(b) the power drawn in kVA
(c) the gross power
(d) the output power available at the shaft
Ans: d
40. Which D.C. motor has got maximum self loading
property?
(a) Series motor
(b) Shunt motor
(c) Cumulatively compounded 'motor
(d) Differentially compounded motor
Ans: d
41. Which D.C. motor will be suitable along with
flywheel for intermittent light and heavy loads?
(a) Series motor
(b) Shunt motor
(c) Cumulatively compounded motor
(d) Differentially compounded motor
Ans: c
42. If a D.C. shunt motor is working at no load and if
shunt field circuit suddenly opens
(a) nothing will happen to the motor
(b) this will make armature to take heavy current,
possibly burning it
(c) this will result in excessive speed, possibly
destroying armature due to excessive centrifugal
stresses (d) motor will run at very slow speed
Ans: c
43. D.C. series motors are used
(a) where load is constant
(b) where load changes frequently
(c) where constant operating speed is needed
(d) in none of the above situations.
Ans: d
44. For the same H.P. rating and full load speed,
following motor has poor starting torque
(a) shunt
(b) series
(c) differentially compounded
(d) cumulativelyc'ompounded
Ans: c
45. In case of conductively compensated D.C.
series motors, the compensating winding is
provided
(a) as separately wound unit
(6) in parallel with armature winding
(c) in series with armature winding
(d) in parallel with field winding
Ans: c
46. Sparking at the commutator of a D.C. motor may
result in
(a) damage to commutator segments
(b) damage to commutator insulation
(c) increased power consumption
(d) all of the above
Ans: d
47. Which of the following motor is preferred for
operation in highly explosive atmosphere ?
(a) Series motor
(b) Shunt motor
(c) Air motor
(d) Battery operated motor
Ans: c
48. If the supply voltage for a D.C. motor is
increased, which of the following will decrease ?
(a) Starting torque
(b) Operating speed
(c) Full-load current
(d) All of the above
Ans: c
49. Which one of the following is not the function of
pole shoes in a D.C. machine ?
(a) To reduce eddy current loss
(b) To support the field coils
(c) To spread out flux for better uniformity
(d) To reduce the reluctance of the magnetic path
Ans: a
50. The mechanical power developed by a shunt
motor will be maximum when the ratio of back
e.m.f. to applied voltage is
(a) 4.0
(b) 2.0
(c) 1.0
(d) 0.5
Ans: d
51. The condition for maximum power in case of
D.C. motor is
(a) back e.m.f. = 2 x supply voltage
(b) back e.m.f. = | x supply voltage
(c) supply voltage = | x back e.m.f.
(d) supply voltage = back e.m.f.
Ans: b
52. For which of the following applications a D.C.
motor is preferred over an A.C. motor ?
(a) Low speed operation
(b) High speed operation
(c) Variable speed operation
(d) Fixed speed operation
Ans: c
53. In D.C. machines the residual magnetism is of
the order of
(a) 2 to 3 per cent
(6) 10 to 15 per cent
(c) 20 to 25 per cent
(d) 50 to 75 per cent
Ans: a
54. Which D.C. motor is generally preferred for
cranes and hoists ?
(a) Series motor
(b) Shunt motor
(c) Cumulatively compounded motor
(d) Differentially compounded motor
Ans: a
55. Three point starter can be used for
(a) series motor only
(b) shunt motor only
(c) compound motor only
(d) both shunt and compound motor
Ans: d
56. Sparking, is discouraged in a D.C. motor
because
(a) it increases the input power con-sumption
(b) commutator gets damaged
(c) both (a) and (b)
(d) none of the above
Ans: b
57. Speed control by Ward Leonard method gives
uniform speed variation
(a) in one direction
(b) in both directions
(c) below normal speed only
(d) above normal speed only.
Ans: b
58. Flywheel is used with D.C. compound motor to
reduce the peak demand by the motor, compound
motor will have
to be
(a) level compounded
(b) under compounded
(c) cumulatively compounded
(d) differentially compounded
Ans: c
59. Following motor is used where high starting
torque and wide speed range control is required.
(a) Single phase capacitor start
(b) Induction motor
(c) Synchronous motor
(d) D.C. motor
(e) None of the above
Ans: d
60. In a differentially compounded D.C. motor, if
shunt field suddenly opens
(a) the motor will first stop and then run in opposite
direction as series motor
(b) the motor will work as series motor and run at
slow speed in the same direction
(c) the motor will work as series motor and run at
high speed in the same direction
(d) the motor will not work and come to stop
Ans: a
61. Which of the following motor has the poorest
speed regulation ?
(a) Shunt motor
(b) Series motor
(c) Differential compound motor
(d) Cumulative compound motor
Ans: b
62. Buses, trains, trolleys, hoists, cranes require
high starting torque and therefore make use of
(a) D.C. series motor
(b) D.C. shunt motor
(c) induction motor
(d) all of above motors
Ans: a
63. As -the load is increased the speed of D.C.
shunt motor will
(a) reduce slightly
(b) increase slightly
(c) increase proportionately
(d) remains unchanged
Ans: a
64. The armature torque of the D.C. shunt motor is
proportional to
(a) field flux only
(b) armature current only
(c) both (a) and (b)
(d) none of the above
Ans: b
65. Which of the following method of speed control
of D.C. machine will offer minimum efficiency ?
(a) Voltage control method
(b) Field control method
(c) Armature control method
(d) All above methods
Ans: c
66. Usually wide and sensitive speed control is
desired in case of
(a) centrifugal pumps
(b) elevators
(c) steel rolling mills
(d) colliery winders
Ans: d
67. The speed of a motor falls from 1100 r.p.m. at
no-load to 1050 r.p.m. at rated load. The speed
regulation of the motor is
(a) 2.36%
(6) 4.76%
(c) 6.77%
(d) 8.84%
Ans: b
68. The armature voltage control of D.C. motor
provides
(a) constant torque drive
(b) constant voltage drive
(c) constant current drive
(d) none of the above
Ans: a
69. As there is no back e.m.f. at the instant of
starting a D.C. motor, in order to prevent a heavy
current from flowing though the armature circuit
(a) a resistance is connected in series with
armature
(b) a resistance is connected parallel to the
armature
(c) armature is temporarily open circuited
(d) a high value resistor is connected across the
field winding
Ans: a
70. The speed of a D.C. shunt motor can be
increased by
(a) increasing the resistance in armature circuit
(b) increasing the resistance in field circuit
(c) reducing the resistance in the field circuit
(d) reducing the resistance in the armature circuit
Ans: b
71. If I2 be the armature current, then speed of a
D.C. shunt motor is
(a) independent of Ia
(b) proportional to la
(c) varies as (Ia)
(d) varies as la
Ans: a
72. In case the back e.m.f. and the speed of a D.C.
motor are doubled, the torque developed by the
motor will
(a) remain unchanged
(6) reduce to one-fourth value
(c) increase four folds
(d) be doubled
Ans: a
73. At the instant of starting when a D.C. motor is
put on supply, it behaves like
(a) a highly resistive circuit
(6) a low resistance circuit
(c) a capacitive circuit
(d) none of the above
Ans: b
74. The speed of a D.C. motor can be varied by
varying
(a) field current
(b) applied voltage
(c) resistance in series with armature
(d) any of the above
Ans: d
75. Which one of the following is not necessarily the
advantage of D.C. motors over A.C. motors ?
(a) Low cost
(b) Wide speed range
(c) Stability
(d) High starting torque.
Ans: a
76. For a D.C. shunt motor if the excitation is
changed
(a) torque will remain constant
(b) torque will change but power will remain
constant
(c) torque and power both will change
(d) torque, power and speed, all will change
Ans: b
77. Which motor has the poorest speed control?
(a) Differentially compounded motor
(b) Cumulatively compounded motor
(c) Shunt motor
(d) Series motor
Ans: d
78. The plugging gives the
(a) zero torque braking
(b) smallest torque braking
(c) highest torque braking
(d) none of the above
Ans: c
79. The armature voltage control of D.C. motor
provides
(a) constant voltage drive
(b) constant current drive
(c) constant torque drive
(d) none of the above
Ans: c
80. If a D.C. motor designed for 40°C ambient
temperature is to be used for 50°C ambient
temperature, then the motor
(a) of lower H.P. should be selected
(6) of higher H.P. should be selected
(c) can be used for 50°C ambient temperature also
(d) is to be derated by a factor recommended by
manufacturer and select the next higher H.P. motor
Ans: d
81. If the terminals of armature of D.C. motor are
interchanged, this action will offer following kind of
braking
(o) regenerative
(b) plugging
(c) dynamic braking
(d) none of the above
(e) any of the above
Ans: b
82. Which of the following motors one will choose to
drive the rotary compressor ?
(a) D.C. shunt motor
(b) D.C. series motor
(c) Universal motor
(d) Synchronous motor
Ans: d
83. If the speed of a D.C. shunt motor is increased,
the back e.m.f. of the motor will
(a) increase
(b) decrease
(c) remain same
(d) become zero
Ans: a
84. Why are the D.C. motors preferred for traction
applications ?
(a) Torque and speed are inversely proportional to
armature current
(b) Torque is proportional to armature current
(c) Torque is proportional to square root of
armature current
(d) The speed is inversely proportional to the torque
and the torque is proportional to square of armature
current
Ans: d
85. Which of the following motors is usually used in
house-hold refrigerators ?
(a) D.C. shunt motor
(b) D.C. series motor
(c) Single phase induction motor (split phase start or
induction run motor)
(d) Reluctance motor
(e) Synchronous motor
Ans: c
86. Which of the following motors is most suitable
for signalling devices and many kinds of timers ?
(a) D.C. shunt motor
(b) D.C. series motor
(c) Induction motor
(d) Reluctance motor
Ans: d
87. Which motor should not be started on no-load ?
(a) Series motor
(b) Shunt motor
(c) Cumulatively compounded motor
(d) Differentially compounded motor.
Ans: a
88. Ward-Leonard control is basically a
(a) voltage control method
(b) field divertor method
(c) field control method
(d) armature resistance control method
Ans: a
89. For constant torque drive which speed control
method is preferred ?
(a) Field control
(b) Armature voltage control
(c) Shunt armature control
(d) Mechanical loading system
Ans: b
90. In Ward-Leonard control the lower limit of
speed is imposed by
(a) residual magnetism of the generator
(b) core losses of motor
(c) mechanical losses of motor and generator
together
(d) all of the above
Ans: a
91. The main disadvantage of the Ward-Leonard
control method is
(a) high initial cost
(b) high maintenance cost
(c) low efficiency at Hght loads
(d) all of the above
Ans: d
92. Regenerative method of braking is based on
that
(a) back e.m.f. is less than the applied voltage
(b) back e.m.f. is equal to the applied voltage
(c) back e.m.f. of rotor is more than the applied
voltage
(d) none of the above
Ans: b
93. The hysteresis loss in a D.C. machine least
depends on
(a) Frequency of magnetic reversals
(b) Maximum value of flux density
(c) Volume and grade of iron
(d) Rate of flow of ventilating air
Ans: d
94. In a D.C. generator all of the following could be
the effects of iron losses except
(a) Loss of efficiency
(b) Excessive heating of core
(c) Increase in terminal voltage
(d) Rise in temperature of ventilating air
Ans: c
95. The losses occurring in a D.C. generator are
given below. Which loss is likely to have highest
proportion at rated load of the generator ?
(a) hysteresis loss
(b) field copper loss
(c) armature copper loss
(d) eddy current loss
Ans: c
96. Which of the following loss in a D.C. generator
varies significantly with the load current ?
(a) Field copper loss
(b) Windage loss
(c) Armature copper loss
(d) None of the above
Ans: c
97. Torque developed by a D.C. motor depends
upon
(a) magnetic field
(b) active length of the conductor
(c) current flow through the conductors
(d) number of conductors
(e) radius of armature
(f) all above factors
Ans: f
98. D.C. shunt motors are used for driving
(a) trains
(b) cranes
(c) hoists
(d) machine tools
Ans: d
99. In a manual shunt motor starter
(a) over load relay is connected in series and no
volt relay in parallel with the load
(6) over load relay is connected in parallel and no
volt relay in series with the load
(c) over load relay and no volt relay are both
connected in series with the load
(d) over load relay and no volt relay are both
connected in parallel with the load
Ans: a
100. Which of the following steps is likely to result
in reduction of hysteresis loss in a D.C. generator ?
(a) Providing laminations in armature core
(b) Providing laminations in stator
(c) Using non-magnetic material for frame
(d) Using material of low hysteresis co-efficient for
armature core material
Ans: d
101. Which of the following loss in a D.C. generator
is dissipated in the form of heat?
(a) Mechanical loss
(b) Core loss
(c) Copper loss
(d) All of the above
Ans: d
102. Which of the following losses are significantly
reduced by laminating the core of a D.C. generator ?
(a) Hysteresis losses
(b) Eddy current losses
(c) Copper losses
(d) Windage losses
Ans: b
103. The total losses in a well designed D.C.
generator of 10 kW will be nearly
(a) 100 W
(b) 500 W
(c) 1000 W
(d) 1500 W
Ans: b
104. The condition for maximum efficiency for a
D.C. generator is
(a) eddy current losses = stray losses
(b) hysteresis losses = eddy current losses
(c) copper losses = 0
(d) variable losses = constant losses
Ans: d
105. D.C. generators are normally designed for
maximum efficiency around
(a) full-load
(b) rated r.p.m.
(c) rated voltage
(d) all of the above
Ans: a
106. In a D.C. generator, the iron losses mainly take
place in
(a) yoke
(b) commutator
(c) armature conductors
(d) armature rotor
Ans: d
107. D.C. generators are installed near the load
centres to reduce
(a) iron losses
(b) line losses
(c) sparking
(d) corona losses
Ans: b
108. The purpose of retardation test on D.C. shunt
machines is to find out
(a) stray losses
(b) eddy current losses
(c) field copper losses
(d) windage losses
Ans: a
109. Which of the following tests will be suitable for
testing two similar D.C. series motors of large
capacity ?
(a) Swinburne's test
(b) Hopkinson's test
(c) Field test
(d) Brake test
Ans: c
110. Hopkinson's test on D.C. machines is
conducted at
(a) no-load
(b) part load
(c) full-load
(d) overload
Ans: c
111. During rheostat braking of D.C. series motors
(a) motor is run as a generator
(b) motor is reversed in direction
(c) motor is run at reduced speed
Ans: a
112. For which types of D.C. motor, dynamic
braking is generally used ?
(a) Shunt motors
(b) Series motors
(c) Compound motors
(d) All of the above
Ans: d
113. Which method of braking is generally used in
elevators ?
(a) Plugging
(b) Regenerative braking
(c) Rheostatic braking
(d) None of the above
Ans: a
114. In variable speed motor
(a) a stronger commutating field is needed at low
speed than at high speed
(b) a weaker commutating field is needed at low
speed than at high speed
(c) same commutating field is needed at low speed
than at high speed
(d) none of the above is correct
Ans: b
115. When the armature of a D.C. motor rotates,
e.m.f. induced is
(a) self-induced e.m.f.
(b) mutually induced e.m.f.
(c) back e.m.f.
(d) none of the above
Ans: c
116. Where D.C. motor of H.P. 12 or more requires
frequent starting, stopping, reversing and speed
control
(a) drum type controller is used
(b) three point starter is used
(c) four point starter is used
(d) all above can be used
Ans: a
117. If a D.C. shunt motor is working at full load and
if shunt field circuit suddenly opens
(a) this will make armature to take heavy current,
possibly burning it
(6) this will result in excessive speed, possibly
destroying armature due to excessive centrifugal
stresses
(c) nothing will happen to motor
(d) motor will come to stop
Ans: a
118. D.C. motor is to drive a load which has certain
minimum value for most of the time and some peak
value for short
duration. We will select the
(a) series motor
(b) shunt motor
(c) compound motor
(d) any of the above
Ans: a
119. D.C. motor is to a drive a load which is almost
nil for certain part of the load cycle and peak value
for short duration. We will select this
(a) series motor
(b) shunt motor
(c) compound motor
(d) any of the above
Ans: c
120. Which D.C. motor has got maximum self
relieving property ?
(a) Series motor
(6) Shunt motor
(c) Cumulatively compounded motor
(d) Differentially compounded motor
Ans: a
121. In the D.C. motor the iron losses occur in
(a) the field
(b) the armature
(c) the brushes
(d) the commutator
Ans: b
122. The speed of a D.C. shunt motor is required to
be more than full load speed. This is possible by
(a) reducing the field current
(b) decreasing the armature current
(c) increasing the armature current
(d) increasing the excitation current
(e) none of the above methods
Ans: a
123. One D.C. motor drives another D.C. motor. The
second D.C. motor when excited and driven
(a) runs as a generator
(b) does not run as a generator
(c) also runs as a motor comes to stop after
sometime
Ans: a

What should a first year graduate student do in Mechanical Engineering School?

This was the answer posted by a person which I find very useful this may not fit our Indian curriculum but try to fall in line and learn So I have written this like the advice I would give myself if I could travel back in time or what I really hope to see in the undergrads. I hope you don't get discouraged/put off.
First thing:
Solid works/ProE/Auto CAD/Rhino/ Blender/CATIA and GD&T are not skills for degree'd engineers. You don't do a BS/ME for draftsmanship. It's like putting MS Office on your resume. You can pick that skill up on your own time. Second thing: I am talking about becoming an engineer here. You know, the kind that build rockets and microengines (Sandia MEMS Home Page ). I have nothing against grades, but I don't care very much for them. So I am not talking about getting the best grades.
Now. Here's what you need to acquire proficiency in through your 4-year BS.
1. Programming -
Start with Mat lab/Python. Then graduate to C++. An example of a programming goal would be to use this to create your own computational graphics engines. Why? Because this teaches you about visualizing vectors, arrays, transforms and leads you to higher-dimensional algebra. Make sure you can understand and implement Runge-Kutta family of algorithms before you think you are done. A recommendation would be to ditch Windows and move to some flavor of Linux or Mac. You need to understand concepts behind batch/shell scripting and importing open source scripts to embed inside your own. If you don't do anything else in your freshman or sophomore years, that's fine. But make sure you master this.
2. Linear algebra and differential equations -
Now, most ME syllabi force the courses on you early on. But very few MEs truly understand these topics. This is the source of all ME theory. I CANNOT STRESS THIS ENOUGH! Most ME professors DO NOT understand linear algebra or its importance   they will fuck it up for you so you will be confused/ avoid derivative topics forever. Don't take these courses offered inside your department - take them from CS or EE or Math professors. Or learn it from Gilbert Strang on Youtube. Tie this together with your programming to create numerical simulations. Do NOT take these courses until you are done with your programming.
3. Statistics -
Take this twice. Audit it as a freshman. Then take the course again as a senior. This will be the single most important course you ever take as a professional in any field.
4. Engineering mathematics -
The rest of your life depends on this. Pay attention to spatial transforms, Fourier analysis, Complex analysis, Potential theory, PDEs, Interpolation/curve fitting, optimization theory. Look for ways to implement these concepts using your programming skills. If you ever wonder about the usefulness of any of this, or you get the choice to skip a few topics - you are doing it wrong. Good engineers use these concepts EVERYDAY.
5. Dynamics/Advanced dynamics -
Take this in the Physics department. ME profs screw it up here again, they focus on the mechanics of algebraic manipulation and don't explain concepts very well. Your objective would be to be able to independently construct FBDs of complex interacting mechanisms, and generate classical non/autonomous, non/linear differential equations that describe the time-history of the system. Develop a familiarity with index notation and tensors and operator spaces. Your indicial programming experience will really help you here.
6. Statics/Solid mechanics -
Master Timoshenko Goodier/Theory of elasticity. Even if it takes you the rest of your life. If you got through point 2, you should be able to point out the inefficiency of the SFDs and BMDs and Mohr's circle concepts. Try  visualizing the simple cases while cognizant that life is not simple. Use your programming finesse to program numerical solutions to your ODEs and equations.
7. Vibration theory -
If you actually got through point 2, you will find this a breeze. All they do here is study a second order, non/homogenous, non/ autonomous non/dimensionalized ordinary differential equation and the effects of parametric variations (mkc, forcing frequency). If you got through 5, you should be able to figure out all the base excitation, seismic perturbation, isolation, rotating machinery concepts. If you got through 6, then plates/beam vibration problems. If you got through 2 & 4, you will be able to work through MDOF systems and all the modal analysis techniques. This is where you segue to coupled SHO/QHO concepts.
8. Thermodynamics/Fluidics -
I am not the right person to advise on these topics. But they are pretty straightforward at the undergraduate level and mostly applications of differential equations and continuum mechanics.


If you followed instructions so far, everything else is a straightforward application of what you  should have learned by now. That's all you really need to be a degree'd mechanical engineer - math and physics. Everything else is a specialization and extension of domains from the presented fields into specific tasks. This is also where you start encountering professional jargon. And don't let terms/eponymous scare you off.

Also mechanical engineers don’t generally design machines from scratch – hobbyists and mathematicians do. We follow standards for our industry, mix and match components, or use well defined algorithms to create a new one. There are concepts in kinematic chains, algebraic linkage synthesis and design that are used here. So sure you can read about gears and machinery and 4-bar linkages and cams and geneva wheels, but it is highly improbable that you, as an ME, will create one. It is more likely that a technician or a sheet metal worker will create something utterly brilliant. So if that’s what you want to do, figure on grad school. You can however use your solid mechanics skills to design the components to withstand pyrotechnic impacts.

I skip over manufacturing and 'product engineering' classes because they are shit, when taught in school. You can't master manufacturing sitting in a class, and you certainly are never going to learn enough in school about how to design a full product.

Those axiomatic design principles and synthetics and product life cycle management and idealization and Gantt charts and brainstorming processes are bullshit. Nobody in real life does that. Those who do, are not engineers. If you really want to understand manufacturing, skim through Manufacturing Processes for Design Professionals by Rob Thompson, then go talk with people on shop floors, or watch how it's made on Youtube. If you really want to understand the product design process, follow Kickstarter h/w startup stories.

Do not ever waste your time on survey or presentation courses. Avoid attending school seminars if you are not interested in the topic. You should attend all seminars that promise to show you math or process or cool videos. You want to keep an ear out for examples and case studies that show explicit details of how systems get modeled/ implemented using math or experiments. Avoid 'design' seminars (usually a peddler from Wharton or Sloan or Kellog) - they are pretty, but pointless.
Take all lab classes you can. ALL of them. All you can afford. Pottery too, if you have that option. Just drop in to watch other people work if you got the free time. Pottery as well. Use the equipment there till you break it - You are paying for it anyway. Make all the mistakes you can ever imagine there. AND DON'T FUCK AROUND IN THE MACHINE SHOP BRO!!!
Amongst other advice, find a PhD student about to graduate every year and get them to mentor you. Don’t believe in that ‘I am busy’ crap – they all are usually on Quora or editing Wikipedia anyway. I
speak from experience. Pick people from diverse fields – machine learning, operations optimization, public policy, neurobiology, kernel development … You want to understand what they do, how they do it, what they use to do it and create a possible job network. You don’t want seniors to mentor you because, unless they go to grad school, they will never be in any position to introduce you to great opportunities on time scales relevant to your interests.

Now, let's talk about being a professional mechanical engineer

9. Read ISO/ASME/ASTM/ASTC/ASMI (standards organizations) standard practices. That's the only
place where they really tell you how theory meets practice. If you believe your university doesn't provide you access to those - Sue them! Beg/ borrow/steal. Whatever. But if you really want to know how things are done; Read the standards. Not the website and their discussion forums. Read the standards.

10. Take/Audit courses on electromagnetism, digital electronics, electrical theory, VLSI/Silicon based
designs, electrical machinery.
You should be able to design your own motor driver/filter/power regulator/multivibrator circuits and implement them on PCBs. Start dipping into embedded microcontrollers here. This is where you C++ experience should start paying off.

11. Signal processing - Audio/image/Power signals
- Master the topic of discrete Fourier transforms/ spectral densities and how they are used and calculated. Figure out how digital sampling and digital filters work and how filters and masks get designed. Move on to z-transforms and recursive filters. Your statistics background starts to become useful here. At least figure out how to manipulate images using pixel-array math.

12. Control systems -
THIS ties up everything. And THIS was the topic that really got you into ME. You didn't join ME to make bridges or prepare CAD layouts for GE ovens or tractor engines or boiler
chambers for plants or be a grease monkey. You joined ME to make structures that move, intelligently. If you have done things right so far, this is where you will get to have fun. It ties together your dynamics and linear algebra first,  then programming, signal processing and statistics
next, finally you implement it all using your electronics/embedded skills.

13. Instrumentation – People have equipment that costs between a thousand dollars to over several million. You need to learn how to use them, AND how to construct them. You will find that making equipment is always cheaper than buying a turnkey system from a manufacturer. So companies prefer to design/assemble their own systems. This should segue into design of experiments/statistical validation. Your goal should be to know how to hook up the hydraulic pressure gauge in an EMD  F51PHI locomotive cab suspended 10 ft up in a shed to an office in Minnesota.
Along with instrumentation, you will frequently need to develop software to control the instruments. Some people use labview, but with your mastery of C/matlab you will do better. If you want to get into finite elements, you can’t do that in undergrad. All you will learn is to push buttons. Most engineers only think they understand FEA – they actually don’t. It takes practice, study  and experience. The pretty pictures don’t mean much by themselves. So I will say go to grad school or intern with a practicing consultant.
That should about cover your basics and get you a good job. But if you want to get a great job, you will  need professional degrees or exhibit skills in some of the following. So, on to specialization:

1. Fracture/fatigue/materials on the nanoscale .
2. MEMS – Look up Sandia National Labs/MEMS.
Biggest opportunity for MEs since all companies are moving from R n D to ramping up production right about now. Micro machining and processing technologies research is active as well. MOEMS was hot, sensors are sizzling, actuators not so much, lab-on-chip was meandering about, last I checked. Significant effort underway on determining lifetime/reliability as well. People were excited about energy harvesting, but that seems to be toned down now. Lot’s of material science opportunities.

3. Microfluidis – These guys blow bubbles through micro channels! Look up lab-on-a-chip.

4. Bioengineering – Tissue printing/engineering! There’s also research on mechanical characterization of bio-materials (bones/ligaments/ RBCs)

5. Medical devices/robotics – da Vinci/intuitive. Also swallowable robots and cameras. Lots of health monitoring devices and OR assistants. 6. Robotics/control systems – Typically, you need to be core CS/EE for this. They are the ones doing most of this research. But you can create opportunities for yourself by choosing to focus on dynamic structure design or kinematics or something on that order. Look up Hod Lipson/ Cornell or Red Whittaker/CMU or Marc Raibert/ex  CMU/MIT leg labs or Rob Wood/Harvard forinspiration. Google and Amazon have raised this field’s profile over the last couple of years.
Look up compliant mechanisms/robots, autonomous vehicles, haptics, telepresence, Raytheon XOS II,... Lot’s of bullshit in the name of ‘assistive robotics’ (that no one can or will want to afford or
use, and medicare won’t support).

7. Control systems/avionics –
I worked on optimizing damage-resilient, real-time coolant distribution through nuclear subs, my ex-boss worked on guidance systems for the Pershing/Hera systems. This is a mature engineering field at the moment (not much RnD) but scope for new applications.
8. Thermo research – They do crazy things with combustion, not my domain.

9. Nonlinear dynamics – Applied theory, predicting weather(?!), galloping (hopf) systems, .. this field
goes on till quantum cryptography and then some.

10. Aerospace vehicles – SpaceX. Etc. Vibrations theory, dynamical systems and controls. Your
vibrations theory needs to be strongly coupled.

11. Infrastructure – Given Keystone or fracking, infrastructure is going to undergo another massive
boom.

12. Petroleum -

13. FEA – Meshing and geometry algorithms, data compression, rendering are being researched

14. Energy – fuel cell research, the cryptozoology equivalent in ME They’ve been at it for a while, but it seems to be a funding generation ploy.

15. Marine systems - …
16. Theoretical systems –
Lots of work on rule based machine learning based design synthesis, structural optimization (back in early 2000’s it was all about simulated annealing and genetic algos, now they call it machine learning), dynamic self modeling, multi-agent systems,

17. MAV/Flight dynamics – Concentrated around rotor craft/flapping wing architectures. Mostly experimental, some theoretical research going on.

18. ICE research – Very avoid!

19. Tribology - Nonlinear dynamics of rate state dependent friction generate P/S/Love/Rayleigh wave phenomena used to predict earthquakes. Studying hydrodynamic lubrication of journal bearings is a trifle boring compared to that.

I have written this like the "Survival guide for mechanical engineers on the journey to create astonishing engineering". This is written with Indian undergrads in mind. So I tend to be didactic, and, in the spirit of times, use hyperbole to signify importance (no selfies, however. Much disappoint.). I also abuse education professionals profusely - But that's only my personal experience – all the additional work I had to put in because courses were not designed right, or because a newly hired asst professor was in charge of a particular course that they had no experience in or because the lecturer, had this distracting accent and circuitous description that just beat about the bush more than I could keep track of or maybe because most of the freshman courses, specially non-core ME courses, are generally fanned out to temp  staff/lecturers that generally don't know jackshit about how things are done or don’t care. So you see, personal failing on my part. That's my excuse for the abuse. And there's catharsis involved as well. So I apologize in advance.

Monday, 27 July 2015

Tips for teaching first class!

As you take on what is likely to be a new experience of having full responsibility for teaching courses in your field, you will also be learning to balance the time you spend on teac​hing, research, and service to your department and the University. Even if you have already had full course responsibility as a Teaching Assistant, you will be taking on a new role of authority in the eyes of the students.

The following tips are meant to help you strengthen your effectiveness as you make the transition into
this new phase of your teaching career:
Take Advantage of the Resources Available to You
Before the Semester Starts: Course Planning
Before Each Class Session or Office Hour
During Each Class Session
After Each Class Session
Working with Students
Recommended Reading
Take Advantage of the Resources Available to You
Do your research.
Ask your colleagues about what you can expect of Washington University students. Ask them what they wish they would have known about teaching before they taught their own courses for the first time. Your colleagues can provide helpful insights about teaching specific courses and about teaching
in general (what works and what doesn’t).
Learn about and participate in Teaching Center programs.
The Teaching Center’s professional-development programs for faculty include workshops (such as a lunch-time series for junior faculty), Teaching Strategies handouts, and scholarship on teaching and learning. Gina Frey, Executive Director of The Teaching Center, is available to observe your teaching and to consult with you on teaching matters, such as course planning, improving student learning, and grading.
Before the Semester Starts: Course Planning
Start by defining course goals.
Rather than beginning by defining the content your course will cover, start by defining your goals for
student learning. Establishing what you want your students to learn (including both knowledge and skills) will help you determine the appropriate content, teaching methods, assignments, and exams. Consider your expected enrollment.
Keep in mind that the methods and approaches you use will be shaped not only by your course goals,
but also by the size of the class and the types of students who will be taking the course (majors or non-majors; first-years, seniors, or a mix; etc.). 
Begin the process early, at least six months in advance if possible.
Give yourself plenty of time to plan the course as well as to order or otherwise make available to students all necessary materials. If you plan to set up a course Web site, seek out any needed technical assistance well ahead of time.
Blackboard , the University’s learning-management system, offers a convenient means of creating a Web-based community for each of your courses. The Campus Bookstore asks for book orders in April for the following fall semester and in October for the following spring semester. The University
Libraries can place materials on "reserve" (electronically or in hard copy) for your students. For information, go to Library. You can also post electronic documents on Blackboard . If you are planning to put together a photocopied packet of readings for students, be advised that it can take several months to obtain copyright clearance from publishers.
Set high, but realistic, expectations for student learning and achievement.
Your students will rise to the occasion and meet your expectations, but only if you plan and approach the course in a way that will provide them with the tools they need to succeed.
Develop assignments and exams that will help your students advance their thinking.
For example, begin with assignments that require them to recall information and define terms, then work up to lengthier assignments and exams that ask them to apply, analyze, synthesize, and evaluate. Establish the course policies.
Establishing all course policies, including those pertaining to academic integrity, grading, and attendance, before the class begins will go a long way toward preventing problems. Keep in mind that
it is always easier to set clear, even rigid policies at the outset and then be flexible later on, when the occasion warrants, than to try to enforce more rigid policies later in the semester. When applying course policies and discussing them with students, make it clear that fairness to all students is your goal. All policies should be included in the course syllabus.
If you are supervising Teaching Assistants (TAs), communicate with them before the semester begins. Determine and explain all TA roles and responsibilities. Ensure that TAs understand, and have opportunities to ask questions about, the course content and policies. Check out your classroom and any available multimedia.
You can see details (including photos) of your classroom by using the Classroom Directory on the Teaching Center Web site. However, it is always best to visit the classroom yourself, so that you can familiarize yourself with the layout and any available multimedia.
Take time to prepare for the first day.
Prepare to teach , rather than just to introduce the course and its requirements, the first time you meet with students so that you can give them a sense of what to expect in the course. You should also be prepared to explain all course requirements and policies, and to give students a clear idea of what you will expect in terms of their participation
Practice your first class session, preferably in the classroom where you will teach. Rehearse how you
will use the chalkboard, how you will manage the time, when you will pause to ask questions, how you will present yourself, etc.
Before Each Class Session or Office Hour Prepare.
Preparation is the best cure for nervousness or uncertainty. Ensure that you have a grasp on the course content as well as access to all necessary materials, including textbooks, lab equipment, and other resources.
As you prepare for each class, help session, or office hour, do not merely go over the same content that the students are learning. Take a broader view, considering the ideas and assumptions behind the content and anticipating questions that students, who may be seeing this material for the first time,
will ask you. Having a “Plan B” ready to go if your “Plan A” does not go as anticipated will help you maintain confidence and control. For example, sometimes a discussion that you expected to last 15 minutes is over in 5, but still achieves the goals you had in mind. Rather than letting the class go early because you have run out of ideas, you can devote the remaining time to another activity that will help the students learn the material (e.g., summarizing the key ideas of the day, asking the students to list what they see as the key ideas, or presenting a problem or mystery that you will solve during the next class).
Plan to use a variety of teaching methods
Expect that your students will bring into the course different learning preferences. While some may be active learners who prefer to solve problems in order to learn concepts, others are reflective learners who prefer to master concepts through uninterrupted reflection. Recognize your own learning preferences and make efforts to extend your approach beyond those preferences. In other words, do not assume that you can teach  something in the same way that you learned it and get the same results with all of your students . You can be most effective if you combine teaching methods to reach as many students as possible: for example, combine verbal and visual explanations, explain concepts using both a “big-picture” and a detail-oriented approach, and give students opportunities for active learning and reflection.
Get organized.
No matter what teaching methods you are using, you can enhance your students’ learning and gain their appreciation if your classes are well organized. Each class period should have a clear beginning,
middle, and end.
Try not to “cover” too much material in a single class period; include time to summarize important points and make connections to material that you covered during the last session.
You can present more information and ideas in a lecture, for example, if you do not summarize and make connections; however, you will reduce the likelihood that the students will learn and retain all
of the material.
Get emotionally ready for each class.
Set aside time right before you teach to focus your mind on your goals for that day and to look forward to teaching—to interacting with students, helping them learn the day’s material, and responding to the questions and ideas that they bring to class.
During Each Class Session
Arrive early, start on time, and end on time.
Showing your respect for everyone’s time will encourage your students to do the same. Arriving at the classroom early will allow you not only to set up for class but also to talk with students  informally.
This informal interaction will help you establish a rapport with your students, which will in turn help
them feel confident to participate in class and to ask for help when they need it. Interact with students; include opportunities for active learning.
Demonstrate from the first class that you are interested in what students are thinking. Include plenty of opportunities for students to ask and answer questions. While a lecture course will provide fewer opportunities for interaction than a discussion course, you will find that students will be able to learn and retain more material if you pause every 15-20 minutes to ask questions or to ask students to apply a theory, solve a problem, or discuss a debated point.
Show passion for the subject and for your students’  learning.
One of the most effective ways to inspire your students to learn is to show that you are truly interested in, and excited about, the course content and their learning.
When responding to your students’ questions and comments, use both verbal and non-verbal cues to show them that you are listening and engaged.
Do not use this time to look down at your notes or remind yourself of the next topic. Students can perceive these actions as indications that you are not truly listening to what they are saying.
Be flexible.
Be prepared to have good days and bad days in the classroom. If you are not getting good results teaching in a particular way, try something new. For example, if the students in your discussion or recitation section are extremely quiet, break them up into smaller groups to solve a problem or answer a set of questions.
If students appear bored, include more opportunities for active learning.
Pause in the middle of class to have students ask and answer questions, provide examples, or solve problems. Do not assume that students look bored because they know the material and then decide to speed up your pace; it may be instead that they are having trouble understanding what you are presenting to them. It may also be that they are sleep-deprived, as college students often are.
If you do not know the answer to a question, say so. Tell the students that you will find an answer, and then get back to them. Present the answer to the entire group during the next class; do not let the
matter drop. You do not need to be all-knowing to maintain your credibility. One way to lose it, in  act, is to bluff by giving an answer of which you are unsure and that students may later find out to be
untrue. Model intellectual curiosity and honesty. Your enthusiasm to learn something new will inspire
your students to follow your example.
When asking questions, do not be afraid of silence. Often, silence means that students are thinking. Do  not give in to the temptation to end the silence by answering your own questions, which will only convince students that if they wait long enough, they will not have to think because you will supply the answers for them. Wait 5-10 seconds for an answer. If, at that point, you are getting blank stares and quizzical expressions, rephrase your question.
After Each Class Session
Jot down brief notes on how it went.
Take five minutes to note what worked and what didn’t, as well as any new ideas that occurred to you while teaching. Include these notes in your lecture notes or lesson plan, so that they will be readily accessible when you are preparing for the next session or teaching the same course again. If you wait until the end of the semester to reflect on how the entire course went, you will have forgotten the specific details that will be helpful to you later.
Make any necessary adjustments to your plan for the next class session.
For example, will you need to clarify or review any material from the session that just ended? Will you need to start at a different point than that which you had anticipated? Do you need to make changes in the way that you present material? Is there anything you can do to improve student participation? Anticipate questions that students may ask in office hours, review sessions, or subsequent classes.
Prepare answers, as well. Do not stick to the material itself. Take a step back to consider why this material is important, what difficulties a novice learner might have with it, and how you might explain it in ways that appeal to different learning preferences (e.g. visual vs. verbal methods).
Working with Students
Learn about your students.
As with anything that you are communicating, you  can be most effective when you shape what you are teaching for your specific audience. In general, be cognizant of your students’ level of familiarity with the course material, as well as their relative intellectual capabilities: for example, undergraduate students will not be prepared to discuss ideas at the same level of complexity and ambiguity that you became accustomed to as a graduate student.  Therefore, you may need to adjust your own language and approach when teaching undergraduates.
The more you know about your students’ academic backgrounds and abilities, the better able you will
be to help them learn what you would like them to learn. You can learn about your students by asking your colleagues about their teaching experiences, by paying attention to the kinds of questions that students ask, or by administering diagnostic exams or informal first-day questionnaires.
Be proactive when dealing with student concerns and complaints.
Some students will feel comfortable coming to you throughout the semester to ask questions. Others
will struggle on their own and need encouragement to seek help in office hours or help sessions. First- year college students, some of whom may be accustomed to excelling academically with less effort than is now required, may have a particularly tough time asking for help. Presenting yourself as
approachable and interested in their questions and concerns will go a long way toward encouraging students to ask for assistance when they need it.
When students come to you with a complaint, take the time to listen to what they have to say before responding. Keep the discussion calm and focused. When you do respond, keep in mind the importance of sticking to your course policies (e.g., on grading and attendance) and University policies (e.g., on academic integrity violations). To ensure fairness for all students, you should make exceptions only when circumstances warrant, and not in order to end a conflict with an individual student. If a student is complaining about a grade, explain the justification behind the grade, but eventually turn the conversation to strategies the student can use to improve her or his performance on the next assignment or exam, or in future courses.
Seek out assistance when you need it.
Often, a student’s academic performance is affected by non-academic issues such as medical concerns or personal problems. If you suspect this may be the case, or if you have simply noticed that a student’s academic performance has declined suddenly, you may find it helpful to consult with the student’s academic advisor or Student Health Services.
Recommend Reading
In last always recommend your students some good reading, so that  they learn themselves how to face problems or create queries, because what student learn from a teacher is just a recommendations of a subject and after that he had to use his knowledge and grab the subject, so its always better to recommend them some good stuff for reading related to latest research, good books, magazines or papers...