Job Interview Questions

1. A hollow shaft of same cross-section area as solid shaft transmits

A. Same torque

B. Less torque

C. More torque

D. Unpredictable

Answer:

B. Less torque

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2. In a cantilever beam, maximum deflection occurs at where

A. Bending moment is zero

B. Bending moment is maximum

C. Shear force is zero

D. Slope is zero

Answer:

A. Bending moment is zero

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3. In a rectangular beam, when width, depth and length are doubled, the bending stress will be

A. Shall remain unchanged

B. Shall be doubled

C. Shall become ¼ th

D. Shall be halved

Answer:

C. Shall become ¼ th

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4. In an I –section beam, the bending moment is resisted mainly by

A. Flanges only

B. Web only

C. Both by flanges and web

D. None of the above

Answer:

B. Web only

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5. In internal combustion (I.C.) engines, combustion of fuel takes place in

A. Outside the cylinder

B. Inside the cylinder

C. Not in the cylinder

D. None of the above

Answer:

B. Inside the cylinder

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6. Power available at the shaft of an I.C engine is known is

A. Brake horse power

B. Indicated horse power

C. Net indicated horse power

D. Pumping power

Answer:

A. Brake horse power

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7. In internal combustion engine piston the maximum temperature occurs at

A. Ring section

B. Gungeon pin

C. Bottom centre

D. Top centre

Answer:

A. Ring section

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8. A two-stroke engine is generally preferred to a four-stroke engine because

A. It offers low fuel consumption

B. It gives lesser shocks and vibrations

C. It can be easily started

D. It has smaller size for the same output.

Answer:

D. It has smaller size for the same output.

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9. During idling process, a petrol engine requires

A. Lean mixture

B. Rich mixture

C. Variable mixture

D. None of above

Answer:

A. Lean mixture

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10. Cavitation in a pipe will begin when

A. Pressure at any location reaches pressure equal to the saturated vapour pressure of liquid

B. Pressure becomes more than critical pressure

C. Flow is increased

D. Pressure is increased

Answer:

A. Pressure at any location reaches pressure equal to the saturated vapour pressure of liquid

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11. Capillary action of liquid is due to the

A. Viscosity of liquid

B. Cohesion of liquid particles

C. Surface tension

D. Adhesion of liquid particles on the surface

Answer:

B. Cohesion of liquid particles

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12. In one ton refrigeration machine, the term “one ton” implies

A. One ton refrigerant is used

B. One ton water can be converted into ice

C. One ton ice when melts from and at 0^oC in 24 hours, the refrigerating effects is equivalent to 3000 kcal/hour

D. None of the above

Answer:

C. One ton ice when melts from and at 0^oC in 24 hours, the refrigerating effects is equivalent to 3000 kcal/hour

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13. In a refrigeration cycle, the moisture content is to be removed before it enters into which system

A. Cold side of system

B. Evaporator

C. compressor

D. condenser

Answer:

B. Evaporator

(1) Pitot tube is used for measurement of
(a) Pressure
(b) Temperature
(c) Discharge
(d) Velocity
Ans.: (d) Velocity

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(2) Slow plastic deformation of material under constant stress is
(a) Creep
(b) Fatigue
(c) Endurance
(d) Elastic deformation
Ans.: (a) Creep

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(3) Mass balancing is done to
(a) Avoid flutter
(b) Increase bending stress
(c) Reduce drag
(d) Distributing mass on control surface
Ans.: (a) Avoid flutter

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(4) Short columns are preferred over long columns from
(a) Strength consideration
(b) Buckling consideration
(c) Weight consideration
(d) None of the above
Ans.: (b) Buckling consideration

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(5) Centre of pressure of an aerofoil with an increase of angle of attack will
(a) Move forward
(b) Move backward
(c) Not move
(d) None of the above
Ans.: (a) Move forward

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(6) Thermal efficiency of a gas turbine plant as compared to diesel engine plant
(a) Higher
(b) Lower
(c) Same
(d) May be higher or lower
Ans.: (a) Higher

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(7) A closed cycle gas turbine works on
(a) Carnot cycle
(b) Rankine cycle
(c) Joule cycle
(d) Atkinson cycle
Ans.: (c) Joule cycle

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(8) A bolt of uniform strength can be developed by
(a) Keeping the core dia of threads equal to the dia of unthreaded portion of bolt
(b) Keeping the core dia of threads smaller than the dia of unthreaded portion of bolt
(c) Keeping the nominal dia of threads equal to the dia of unthreaded portion of bolt
(d) None of the above
Ans.: (a) Keeping the core dia of threads equal to the dia of unthreaded portion of bolt

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(9) Stress concentration factor is defined as ratio of
(a) Max stress to endurance limit
(b) Nominal stress to endurance limit
(c) Max stress to nominal stress
(d) Nominal stress to max stress
Ans.: (c) Max stress to nominal stress

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(10) Principle effect of humidity is
(a) Corrosion
(b) Leaking from sealed enclosures
(c) Permanent set of packing and gaskets
(d) Differential contraction of metal parts
Ans.: (a) Corrosion

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(11) Backlash is
(a) Sum of the clearance of two gears
(b) Mutual play between two gears
(c) Amount by which the width of a tooth space exceeds the thickness of the engaging tooth on pitch circle
(d) Any of the above
Ans.: (c) Amount by which the width of a tooth space exceeds the thickness of the engaging tooth on pitch circle

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(12) Teflon is used for bearings because of
(a) Low co-efficient of friction
(b) Better heat dissipation
(c) Smaller space constraint
(d) All of the above
Ans.: (a) Low co-efficient of friction

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(13) When two elastic bodies collide with each other
(a) Two bodies will momentarily come to rest after collision
(b) The two bodies tend to compress & deform at the surface of contact
(c) Two bodies begins to retain their original shape
(d) All of the above
Ans.: (d) All of the above

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(14) Antifriction bearings are
(a) Thick lubricated bearing
(b) Thin lubricated bearing
(c) Ball & roller bearing
(d) Plastic bearing
Ans.: (c) Ball & roller bearing

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(15) What is Hertzian stress?
(a) Tensile stress on inner surface of cylinder
(b) Bending stress on two contact surface
(c) Contact stress on two contact surfaces
(d) Shear stress on two contact surfaces
Ans.: (c) Contact stress on two contact surfaces

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(16) Mohr’s circle can be used to determine following stress on inclined surface
(a) Principal stresses
(b) Normal stresses
(c) Maximum shear stresses
(d) All of the above
Ans.: (a) Principal stresses

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(17) What size of material required for making rolled threads?
(a) Pitch diameter
(b) Root diameter
(c) Major diameter
(d) None
Ans.: (a) Pitch diameter
1. Normalizing operation is carried out in
a) Water
b) Oil
c) Air
d) Furnace

Ans.: c) Air

2. The main purpose of heat treatment of steels is to change the
a) Chemical composition
b) Mechanical properties
c) Surface finish
d) Physical properties

Ans.: b) Mechanical properties

3. Which of the following is a non-destructive test
a) Impact test
b) Charpy test
c) Cupping test
d) Radiography test

Ans.: d) Radiography test

4. Polymerization is associated with
a) Stainless steel
b) Cast iron
c) Thermoplastic
d) Duralumin

Ans.: c) Thermoplastic

5. The material of pattern in the investment casting is
a) Resin
b) Sand
c) Wax
d) Wood

Ans.: c) Wax

6. Shell moulding process requires
a) Wooden pattern
b) Plastic pattern
c) Sand pattern
d) Metal pattern

Ans.: d) Metal pattern

7. Liquid nitrogen containers can be made from
a) Ferritic stainless steel
b) HSLA steel
c) Titanium
d) Austenitic stainless steel

Ans.: d) Austenitic stainless steel


8. Stretching of rolled rings is done to
a) To meet dimensional requirement
b) To relieve stresses
c) To introduce stresses
d) To improve finish

Ans.: b) To relieve stresses

9. During manufacturing of spring, the coiling pitch is assumed to be larger than specified pitch by
a) 5-8%
b) 10-12%
c) 2-5%
d) none

Ans.: a) 5-8%

10. Metric thread have included angle:
a) 60°
b) 55°
c) 30°
d) None

Ans.: a) 60°

11. Which part of the cutting tool is prone to crater wear
a) Flank
b) Face
c) Shank
d) Base

Ans.: b) Face

12. The crater wear of a cutting tool is due to
a) Chemical action of the coolant
b) Excessive heat generated during cutting operation
c) Rubbing of tool against the work piece
d) Abrasive action of the chip

Ans.: d) Abrasive action of the chip

13. Crater wear is predominant in
a) Carbon tool steels
b) Tungsten carbide tools
c) High speed steel tools
d) Ceramic tools

Ans.: b) Tungsten carbide tools

14. Identify the single point cutting tool
a) Milling cutter
b) Hacksaw blade
c) Grinding wheel
d) Cutting tool used in a slotting machine

Ans.: d) Cutting tool used in a slotting machine

15. The angle between the tool face and the plane parallel to the base of the cutting tool is called
a) Lip angle
b) Cutting angle
c) Rack angle
d) Shear angle

Ans.: c) Rack angle

16. In metal cutting operation, the cutting angle is defined as the angle
a) between the flank and the horizontal machined surface
b) between the shear plane and the direction of tool travel
c) between the face of tool and the line tangent to the machined surface at the cutting point
d) between the tool face and the ground end surface of flank

Ans.: c) between the face of tool and the line tangent to the machined surface at the cutting point

17. The angle between the face and the flank of the single point cutting tool is known as
a) Rack angle
b) Clearance angle
c) Lip angle
d) Point angle

Ans.: b) Clearance angle

18. Cutting tool may be provided with large positive rack angle to
a) Have a better heat dissipation
b) Avoid rubbing with the finished surface
c) Increase the strength of cutting edge
d) Reduce the magnitude of cutting forces

Ans.: d) Reduce the magnitude of cutting forces

19. Single point thread cutting tool should ideally have
a) Zero rack angle
b) Positive rack
c) Negative rack
d) Normal rack

Ans.: a) Zero rack angle

20. With an increase in nose radius of single point cutting tools
a) Tool life increases
b) Excessive heat is generated
c) Surface finish deteriorates
d) Cutting speeds have to be kept small

Ans.: a) Tool life increases

21. Tool signature
a) Is a pictorial view of the tool
b) Outlines the orthographic projection of the tool
c) Represents complete specification of the tool
d) Is a numerical method of tool identification
e) Indicate life of tool

Ans.: d) Is a numerical method of tool identification

22. The cutting speed of a tool refers to
a) Revolution made by the tool in a specified time
b) Revolutions turned by the job in a specified time
c) Distance travelled by the tool in one revolution of the job
d) Rate at which cutting edge of the tool passes over the surface of work piece

Ans.: d) Rate at which cutting edge of the tool passes over the surface of work piece


23. Which is not the primary function of coolant in a metal cutting operation
a) To cool the tool and work piece and conduct the heat generated
b) To improve the cutting action
c) To help in giving bright shining surface to the job
d) To reduce the friction at the cutting point

Ans.: a) To cool the tool and work piece and conduct the heat generated


24. Choose the coolant that would be most appropriate for light cuts on aluminum alloys
a) Kerosene
b) Mineral oil
c) Soluble oil or emulsions
d) Straight fatty oil

Ans.: a) Kerosene


25. Tool life may be measured by the
a) Total time the tool has been in contact with the job
b) Quantity of material removed between the total sharpening
c) Number of work pieces machined between tool sharpening
d) Time for the flank wear to reach a certain dimension
e) Any one of the above

Ans.: e) Any one of the above

26. The tool life is influenced maximum by
a) Cutting speed
b) Tool material and geometry
c) Cutting fluid
d) Surface conditions of the workpiece
e) Skill of the operator

Ans.: a) Cutting speed

1. Draft on pattern means
b) Allowance for machining
c) Locating pad
d) Compensate for stripping
e) Compensation for shrinkage



Ans.: d) Compensate for stripping


2. Slag inclusion in the casting is a
a) Surface defects
b) Internal defect
c) Crack
d) Notch



Ans.: a) Surface defects

3. Fettling is an operation performed
a) Before casting
b) After casting
c) During casting
d) After heat treatment



Ans.: b) After casting
 
4. Sprue in casting refers to
a) Gate
b) Runner
c) Riser
d) Vertical passage



Ans.: d) Vertical passage

5. Severe quenching can cause
a) Blow holes
b) Warping
c) Inclusions
d) Non of them

Ans.: b) Warping

6. Casting defects caused by the molten metal is
a) Blow holes
b) Swell
c) Scab
d) All of the above

Ans.: d) All of the above

7. Forming operation which does not involve rotation of work piece is
a) Spinning
b) Thread rolling
c) Ring rolling
d) Upsetting

Ans.: d) Upsetting

8. In hot working process
a) Poor surface finish is produced
b) Scale formed
c) Close tolerance is difficult to maintain
d) All of the above

Ans.: d) All of the above

9. Swaging is an operation of
a) Extrusion
b) Forging
c) Casting
d) Rolling

Ans.: b) Forging

10. Age hardening is related with
a) Stainless steel
b) Duralumin
c) Gun metal
d) Cast iron

Ans.: b) Duralumin

11. Foundry crucible is made of
a) Stainless steel
b) Mild steel
c) Lead
d) Graphite

Ans.: d) Graphite


12. A 1000 tonne press implies that
a) The weight of press is 1000 tonne
b) The press can handle works weighing up to 1000 tonne
c) It can exert pressure up to 1000 tonne
d) Its turn over in a day is 1000 tonne

Ans.: c) It can exert pressure up to 1000 tonne

13. The transistor is made of
a) Silver
b) Germanium
c) Copper
d) Cast iron

Ans.: b) Germanium

14. Pre heating is essential in welding of
a) High speed steel
b) German steel
c) Stainless steel
d) Cast iron

Ans.: a) High speed steel

15. Spring back phenomenon occurs in
a) Forging
b) Hot penning
c) Spinning
d) Bending

Ans.: d) Bending

16. Wire is made by
a) Drawing
b) Forging
c) Rolling
d) Casting

Ans.: a) Drawing

17. Greater forging capacity is achieved with
a) Mechanical press
b) Power hammer
c) Hydraulic press
d) Non of them

Ans.: c) Hydraulic press

18. Turbine rotor is made by
a) Rolling
b) Sand casting
c) Forging
d) Extrusion

Ans.: b) Sand casting

19. Which of the following welding process uses consumable electrodes
a) TIG
b) MIG
c) Thermit
d) Laser

Ans.: b) MIG

20. The phenomenon of weld decay occurs in
a) Cast iron
b) Brass
c) Bronze
d) Stainless steel

Ans.: d) Stainless steel

21. The crystal structure of alpha iron
a) BCC
b) FCC
c) HCP
d) Cubic

Ans.: a) BCC

22. The hardest known material is
a) Ceramic
b) High speed steel
c) Cemented carbide
d) Diamond

Ans.: d) Diamond

23. Which of the following is the most ductile material
a) Lead
b) Copper
c) Mild steel
d) Vanadium

Ans.: a) Lead

24. Brinell hardness tester uses a hardened steel ball of size
a) 1 mm
b) 5 mm
c) 10 mm
d) 15 mm

Ans.: c) 10 mm

25. Trimming process is associated with
a) Polishing of metals
b) Machining
c) Electroplating
d) Forging

Ans.: d) Forging

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Filed Under: Interview Questions, Mechanical Engineering on Thursday, January 30, 2014 No Comments

Throttling Process

Throttling is a process in which the flow of fluid is restricted by closing the valve partially. Now imagine their are students in a class room and as the bell rungs they started moving out. Now if the door is opened partially then their will be clusters form by the students. Similarly in flow of fluid their is restriction to flow. now as students form clusters they pushing other students and in the same way fluid particles start rubbing with other molecules and as a result friction is their and as we all know friction is one of the biggest reason for any process to make it irreversible.

Hence it is clear that Throttling is irreversible.

EXAMPLES OF THROTTLING PROCESS
1. Flow through a partially opened valve as in IC engines
2. Flow through a very small opening e.g orifice.
3. Flow through a porous plug.

Characteristics of Throttling
1. No Work Transfer
Explanation:
As we know their is work transfer in turbines due to very large pressure difference. but in the case of throttling their is very low pressure differences so the work we get is very small and this work is lost in overcoming friction. so here we generally neglect the work transfer.

2. No Heat Transfer
Explanation:
Lets see it with a example... imagine you open the freeze and took out your water bottle and just within the fraction of seconds you put back that bottle, now what is the temperature difference between the two states of the water bottle, it is approx. zero. It means heat transfer needs some time , now what happened in throttling is that device length is very small and the fluid is always pushed ahead due to the bulk coming and due this their is not much time for the heat transfer. As we are considering the steady flow and bulk is not accumulated in the device so heat transfer is also neglected.

3. Irreversible Process

4. Isenthalpic Process
Explanation:
The word ISENTHALPIC means same Enthalpy.
look we apply steady flow energy equation:

now neglecting potential energy changes and
heat transfer(q) and work transfer (w) are zero as the characteristics of throttling..

equation becomes:

now what we generally seen that practically velocities values (c1 and c2 ) are very very small as compared to enthalpies values so c1 and c2 can be neglected and finally

hence the process is Isenthalpic.

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CNC MACHINES

The abbreviation CNC stands for computer numerical control, and refers specifically to a computer "controller" that reads G-code instructions and drives a machine tool, a powered mechanical device typically used to fabricate components by the selective removal of material. CNC does numerically directed interpolation of a cutting tool in the work envelope of a machine. The operating parameters of the CNC can be altered via a software load program.



Historical overview

CNC was preceded by NC (Numerically Controlled) machines, which were hard wired and their operating parameters could not be changed. NC was developed in the late 1940s and early 1950s by John T. Parsons in collaboration with the MIT Servomechanisms Laboratory. The first CNC systems used NC style hardware, and the computer was used for the tool compensation calculations and sometimes for editing.

Punched tape continued to be used as a medium for transferring G-codes into the controller for many decades after 1950, until it was eventually superseded by RS232 cables, floppy disks, and now is commonly tied directly into plant networks. The files containing the G-codes to be interpreted by the controller are usually saved under the .NC extension. Most shops have their own saving format that matches their ISO certification requirements.



The introduction of CNC machines radically changed the manufacturing industry. Curves are as easy to cut as straight lines, complex 3-D structures are relatively easy to produce, and the number of machining steps that required human action have been dramatically reduced.

With the increased automation of manufacturing processes with CNC machining, considerable improvements in consistency and quality have been achieved with no strain on the operator. CNC automation reduced the frequency of errors and provided CNC operators with time to perform additional tasks. CNC automation also allows for more flexibility in the way parts are held in the manufacturing process and the time required to change the machine to produce different components.One new emerging technology currently being used in the metal industry is the CNC machine CNC stands for computer numerical control



Production environment

A series of CNC machines may be combined into one station, commonly called a "cell", to progressively machine a part requiring several operations. CNC machines today are controlled directly from files created by CAM software packages, so that a part or assembly can go directly from design to manufacturing without the need of producing a drafted paper drawing of the manufactured component. In a sense, the CNC machines represent a special segment of industrial robot systems, as they are programmable to perform many kinds of machining operations (within their designed physical limits, like other robotic systems). CNC machines can run over night and over weekends without operator intervention. Error detection features have been developed, giving CNC machines the ability to call the operator's mobile phone if it detects that a tool has broken. While the machine is awaiting replacement on the tool, it would run other parts it is already loaded with up to that tool and wait for the operator. The ever changing intelligence of CNC controllers has dramatically increased job shop cell production. Some machines might even make 1000 parts on a weekend with no operator, checking each part with lasers and sensors.

Types of instruction

Main article: G-code

A line in a G-code file can instruct the machine tool to do one of several things.

Movements

Lately, some controllers have implemented the ability to follow an arbitrary curve (NURBS), but these efforts have been met with skepticism since, unlike circular arcs, their definitions are not natural and are too complicated to set up by hand, and CAM software can already generate any motion using many short linear segments.

Drilling

A tool can be used to drill holes by pecking to let the swarf out. Using an internal thread cutting tool and the ability to control the exact rotational position of the tool with the depth of cut, it can be used to cut screw threads.

A drilling cycle is used to repeat drilling or tapping operations on a workpiece. The drilling cycle accepts a list of parameters about the operation, such as depth and feed rate. To begin drilling any number of holes to the specifications configured in the cycle, the only input required is a set of coordinates for hole location. The cycle takes care of depth, feed rate, retraction, and other parameters that appear in more complex cycles. After the holes are completed, the machine is given another command to cancel the cycle, and resumes operation.

Parametric programming

A more recent advancement in CNC interpreters is support of logical commands, known as parametric programming. Parametric programs incorporate both G-code and these logical constructs to create a programming language and syntax similar to BASIC. Various manufacturers refer to parametric programming in brand-specific ways. For instance, Haas Automation refers to parametric programs as macros. GE Fanuc refers to it as Custom Macro A & B, while Okuma refers to it as User Task 2. The programmer can make if/then/else statements, loops, subprogram calls, perform various arithmetic, and manipulate variables to create a large degree of freedom within one program. An entire product line of different sizes can be programmed using logic and simple math to create and scale an entire range of parts, or create a stock part that can be scaled to any size a customer demands.

Parametric programming also enables custom machining cycles, such as fixture creation and bolt circles. If a user wishes to create additional fixture locations on a work holding device, the machine can be manually guided to the new location and the fixture subroutine called. The machine will then drill and form the patterns required to mount additional vises or clamps at that location. Parametric programs are also used to shorten long programs with incremental or stepped passes. A loop can be created with variables for step values and other parameters, and in doing so remove a large amount of repetition in the program body.

Because of these features, a parametric program is more efficient than using CAD/CAM software for large part runs. The brevity of the program allows the CNC programmer to rapidly make performance adjustments to looped commands, and tailor the program to the machine it is running on. Tool wear, breakage, and other system parameters can be accessed and changed directly in the program, allowing extensions and modifications to the functionality of a machine beyond what a manufacturer envisioned.

There are three types of variables used in CNC systems: local variable, common variable, and system variable. Local variable is used to hold data after machine off preset value. Common variable is used to hold data if machine switch off does not erase form data. The System variable this variable used system parameter this cannot use direct to convert the common variable for example tool radius, tool length, and tool height to be measured in millimeters or inches.

Typical logic to a parameter program is as follows;

First define variables to start your program.
-bolt circle radius
-how many holes
-centerpoint of bolt circle
Next build a subprogram that crunches the math.
When you are ready to drill or tap your holes, run the drill cycle
off of your math in subprogram.


Tool call,
spindle speed,and offset pickup,etc
G43 in some cases (tool length pickup)
G81(drill cycle)
call sub program
N50
G80
M30

Subprogram
N100 (this line here is used as a marker)
#100=15 (this line is your radius)
#105=((COS#104)*#100) (x location)
#106=((SIN#104)*#100) (y location)
x#105 y#106 (remember your G81 code is modal)
If #104 GT 360 goto N50
#104=(#104+(360/#101))
Goto 100

This is just a model to show the logic of programming.
As all languages have some differences, the logic is all similar.

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How to get Government PSU engineering jobs through GATE 2014

Are you looking for engineering jobs in Government of India public service undertakings? This article provides information on how GATE 2014 provides a great opportunity to get an engineering job with BPCL, IOCL, HPCL, Power Grid, etc and secure your future. You will get details about the online application process for applying for the recruitment to these companies.

Introduction GATE is the Graduate Aptitude Test in Engineering. This test is mandatory for all the graduate engineering students who wish to pursue higher studies at any of the Indian Institutes of Technology (IIT) or at the Indian Institute of Science (IISc). Even better, you have the opportunity of getting a job in one of the top Govt. of India public sector undertakings. Your scores can help you to start as a management trainee or even apply directly to be an assistant engineer or engineer. At the time of writing this article, Hindustan Petroleum Corporation Ltd., Indian Oil, Bharat Petroleum Corporation Limited and Power Grid have released their recruitment notifications for graduate engineers to join their respective companies through GATE 2014. You can also apply for 2014 GAIL executive trainee engineer posts For details on GATE 2014 and online submission of your application form, visit any of the IIT websites or visit http://gate.iitkp.ac.in/gate2014/ between 2nd September 2013 and 1st October 2013. HPCL recruitment through GATE 2014 Hindustan Petroleum Corporation Ltd (HPCL) is a Govt. of India enterprise. HPCL is a refining and marketing company and operates the largest Lube refinery in India. HPCL invites applications from dynamic engineering graduates to join its team of professionals. Interested candidates must appear for GATE 2014 for their respective disciplines. The specified disciplines & prescribed full time degrees are: Mechanical: Engineering degree in Mechanical, Mechanical & Production Civil: Engineering degree in Civil Electrical: Engineering degree in Electrical, Electrical & Electronics Electronics & Telecomm: Engineering degree in Electronics, Electronics & Communication, Electronics & Telecommunication Instrumentation: Instrumentation, Instrumentation & Control, Electronics & Instrumentation, Instrumentation & Electronics Note: You are not eligible to apply if you havy any other degree or combination degree, such as Production Engineering, Automobile Enineering, Mechatronics, etc. Eligibility criteria You must have a Bachelor's degree (through full time course) in engineering/technology in the disciplines mentioned above from any AICTE approved / UGC recognized University/Deemed University. You should have scored minimum 60% marks (aggregate marks of all semesters) in the degree exam (50% for SC/ST/PWD candidates). Age: You should be maximum 25yrs. of age as on 30th June 2014 ( i.e.born on or after 30/06/1989). There is age relaxation for OBC (Non Creamy Layer)/SC/ST/PWD candidates. You will need to be medically fit as per the company's pre-employment medical standards. It is advisable to check the company's website to know these medical standards before applying for the recruitment How to apply You should check full details of the recruitment advertisement at the official website: www.hindustanpetroleum.com/ or www.hpclcareers.com You have to submit your application online only at the official website up to 7th January 2014. The online application system will be open from 1200 hrs. on 5th November 2013 to 2400 hrs. on 7th January 2014. The payment of application fees will be accepted till 1700 hours on 11th Jan 2014. The online application for applying will be disabled after 2400 hours on 07.01.2014. Important Dates Commencement of online application for GATE 2014: 2nd September 2014 Last date of online application for GATE 2014: 3rd October 2014 Commencement of online Registration of application by candidates for HPCL: 5th November 2013 Last date for online registration of application by candidates for HPCL: 7th January 2014 GATE 2014 Online Examination: check official GATE website. IOCL recruitment through GATE 2014 Indian Oil Corporation Ltd (IOCL) is a globally reputed energy major. It operates one of Asia's largest networks of refineries & pipelines and markets petroleum products. IOCL is inviting dedicated graduate engineers for recruitment as Officers / Engineers in the following disciplines: Chemical Engineering Civil Engineering Computer Science & IT Electrical Engineering Instrumentation Engineering Mechanical Engineering Metallurgy The recruitment will be through GATE 2014 for both the positions: Officers / Engineers and Assistant Officers / Assistant Engineers. GATE scores from GATE 2013 or any previous exam is not valid and will not be considered. Basic Pay Officers/Engineers: Rs.24,900/- - Rs.50,500/- per month Assistant Officers/Assistant Engineers: Rs.20,600/- - Rs.46,500/- per month Important Notes: You may apply for Officers/Engineers or Assistant Officers/Assistant Engineers or both. The final merit will be based on the GATE 2014 score. Further selection process will include: (1) a Group Discussion (GD), (2) a Group Task (GT) and (3) Personal Interview (PI). If you are higher on merit, you will be offered the position of Officers/Engineer and if you have a lower merit you will be offered the position of Assistant Officer/Assistant Engineer. You need to check out the details for educational qualification, age, eligibility criteria, application procedure, etc at the official website: www.iocl.com How to apply You will need to apply online separately for GATE 2014 and for the Indian Oil recruitment. You can apply for the Indian Oil recruitment only after getting your GATE 2014 registration number. The online application module for Indian Oil's recruitment will be open from 18th December 2013 to 2nd March 2014. BPCL recruitment through GATE 2014 Bharat Petroleum Coroporation Limited (BPCL) is a Govt. of India undertaking. It is a globally reputed company in the Oil & Gas industry. BPCL is inviting applications from young mechanical and chemical engineers to join as Management Trainees. Qualification criteria You will be selected on the basis of your GATE 2014 score. For detailed advertisement and information on the selection process, eligibility criteria, etc, you should visit the official website: www.bpclcareers.in How to apply You should apply separately for the BPCL recruitment online from 20th December 2013 to 31st January 2014 at the BPCL website along with your GATE 2014 registration number. Power Grid recruitment through GATE 2014 Power Grid Corporation of India Ltd. Is a Navaratna Public Sector Undertaking under the Ministry of Power, Govt. of India. The company is one of the world's largest power transmission utilities. Power Grid invites smart engineering graduates in the Electrical discipline to join the company as executive trainees. Batch: 2014 ET-19th Batch Eligibility criteria You should have completed B.E./ B.Tech/ B.Sc (Engg) from recognized University/Institute with Minimum 65% or equivalent CGPA in the following disciplines: Electrical Electrical (Power) Electrical and Electronics Power Systems Engineering OR Have completed AMIE course in Electrical discipline with Minimum 65% with both Sections A & B cleared by 31st March 2014 You should have a valid GATE 2014 score Age: upper age limit is 28 years as on 31st December 2013 Additional Information The notification with details regarding the job vacancies, instructions on how to submit the online application, date of interview etc. will be hosted on the official website, from 7th January 2014 Group Discussion and Personal Interview will likely be conducted in the month of April/May 2014 For details about the eligibility criteria and selection procedure, visit the career section at the official website: www.powergridindia.com For any queries regarding this recruitment please send email to et19@powergridindia.com with "ET 19-____________" in the subject line. Important Dates Commencement of Online Submission of Application to Power Grid(tentative): first week of January 2014 Last date for Online submission of Application to Power Grid(tentative): second week of February 2014 All the best!

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GATE Preparation tips for upcoming exam: GATE 2014

This article gives you some tips and help regarding the next/upcoming GATE examination i.e. GATE 2014. This will help to any young aspirant engineering student to get good score in any GATE exam. Read the article to get more about GATE exam preparation tips.

Introduction and Importance of GATE examination

GATE stands for Graduate Aptitude Test in Engineering. GATE an entrance exam which is mandatory in IIT (Indian Institute of Technology) and NIT(National Institute of Technology) and it is sometimes preferable by other state engineering colleges for entry to master level programs like Master of Technology (M. Tech.) and Master of Engineering (M. E.). Some industries also look for GATE qualified candidate for interview or job hiring because GATE consists of most of the syllabus covered during graduation. So, a candidate with good GATE score is considered to be most eligible for higher education as well as job. Recently Navratna companies or some PSU (Public Sector Units) like Bharat Petroleum Corporation Limited (BPCL), NTPC Limited ( National Thermal Power Corporation), Hindustan Petroleum Corporation Limited (HPCL), Bharat Electronics Limited (BEL), Gas Authority of India Limited (GAIL), Indian Oil Corporation Limited (IOCL), Heavy Engineering Corporation Ltd (HECL), have made GATE qualification mandatory for first stage of interview exam for hiring. So, now it is almost mandatory for every engineering graduate.

Details about GATE 2014

Graduate Aptitude Test in Engineering (GATE)-2014 will be conducted all over India by IIT on behalf of MHRD ( Ministry of Human Resource Development). The GATE 2014 exam date is 9th February, 2014. Always remember, GATE is conducted every year on second Sunday of February.

GATE exam pattern:

GATE exam consists of 100 marks paper which will consists of two sections according to the nature of questions asked. One section involve engineering questions and other will involve General Aptitude. The engineering questions will be of short numerical type or theoretical type. The short numerical is having either two or one marks and theoretical question will have one marks. Also GATE consider 'negative marking'. You will lose 1/3 mark for each wrong answer for 1 mark questions. And 2/3 marks for each wrong answer for 2 marks questions. So, think 'thrice' before writing any answer in GATE!

How to prepare for the GATE?

Below I have given some GATE preparation tips which might help every candidate of GATE who are going to appear for next GATE exam. These GATE preparation tips are my experience during GATE 2006 when I gave GATE in my final year. If you are apply for the first time, it is very necessary to follow each and every tips mentioned below. Chanakya said that 'It is better to learn from other's experience rather than first experience it with ourselves'. So, these tips will be helpful while appearing for the first time in GATE exam or for will improve your score or aptitude in GATE compared to previous years.

1. Technical tips for GATE exam

Study the syllabus

The first step to start preparation for GATE is to study the complete syllbus of your specialization. If you are in Mechanical Engineering, you should download the syllabus for GATE - Mechanical Engineering (ME) and try to study the syllabus. Here study means which are the subjects you need to study well, Which subject's syllabus involves 'numerical' and which involve only 'theoretical stuffs'? If you are in still graduate student and want to give GATE exam in future, you should first compare the subject's GATE syllabus with syllabus of your curriculum of your university. You should pay more attention to those topics which are common. Thus, you can start preparing for the GATE in well advance and you will get plenty of time for nice GATE preparation.

Solve previous year GATE papers

You should first check which type of questions are asked in GATE exam and this can only possible if you study or solve the previous year GATE papers. Download the previous year GATE papers and check all the papers w.r.t. each subject in GATE syllabus and determine which subject are most important for GATE. Thus, you can do smart preparation of GATE otherwise 20-30 subjects are hard to study for GATE. You should do smart preparation instead of hard preparation! Normally GATE exam asks those question which are most related to master's program. So, you can understand which subject are important. For Mechanical Engineering, Thermal subject, Design subjects and Manufacturing subjects are most important.

Concentrate more on basic concepts

The main objective behind GATE exam is to check basic knowledge. To study master or research program, it is mandatory to have sound basics in those field so, GATE exam mostly deal with checking of basic concepts. They will never ask definition but they will push you to think for an answer. You will never get straight forward answer to any question. You will find two or more options right for a question. You need to decide which is correct out of many similar answers.

Prepare subject notes

If you have skipped some content during your graduation, try to read it first from class notes rather than wasting time in reading same what you already know. If you are still in under graduate study, cultivate habit of preparing class note or subject note keeping GATE in mind. The note taking will help you to do revision very easily in last few days before GATE.

2. Non technical tips for GATE exam

One should always remember following these tips for every exam.

• First and foremost requirement to clear GATE with good score is determination and perseverance to do well in GATE. Because you will get only one chance to improve your score every year. You need to wait for another year to apply again and improve the score. So, have determination to do well and try to do serious preparation. Do not give GATE exam just for passing. You will stand no where if you are having just a GATE score instead of 'Good GATE Score'.


• You cannot wait for right time for GATE exam preparation. Just do it now. If you wait for right time, that time will never come and you will waste your time just by procrastination.


• When you decide to give GATE, from that moment onward you should think of GATE only. Just think how you will get good or high GATE score? Try to visualize the moment that you got high GATE score. The law of Attraction (LOA) will help you to do so.


• Yoga and Exercise will keep you charged with positive energy. You can feel the difference once you start doing it. This will keep you positive and improve you self confidence.


• Always start from the question for which you are confident enough. Do not waste time in thinking more on strange questions.


• Never try to attempt all the questions. If you just attempt few but very correct, you will get high score compared to those who attempt maximum but reach to bottom due to negative marking. I have attempted only 23 questions in GATE 2006 and I got 90.26 (Means I was in top 9.74% student for that year)percentile during that year. Just do best compared to others.


• Always make preparation time table for each subject and manage the time accordingly. Do not make so tight schedule tat you cannot adhere to it. Just make it flexible.


• Solve practice papers available online and try to improve the score each time.


• Take advice and help of your teachers because they already passed the GATE! You can meet your seniors and parents to get guidance about preparing mind for the exam.


• Do not compare your preparation with others, otherwise you will lose self confident and result performance too. Every body has their own way and we cannot judge them by any means.


• Do preparation on quality level not on quantity level. Some student say he/she usually read more than 15 hours during exam time. What is the meaning of these 15 hours without any quality reading?

 

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Comparison between MacPherson & Double Wishbone Suspension System

Two of the most popular suspensions systems for passenger cars today are the double wishbone suspension system and the MacPherson’s strut suspension system. While it is more usual to see the double wishbone system at the rear end of the car,  MacPherson’s solution normally finds its place at the front end of the car. Both types of suspensions have their own sets of benefits and limitations, thus let us look at both the advantages and disadvantages of both systems, starting with the simpler of the two, the MacPherson struts.

MacPherson Struts- The struts are designed with more simplicity, and thus takes up less space horizontally. As a result, passengers get more compartment place in the car. They also display low un-sprung weight, an advantage that reduces the overall weight of the vehicle as well as increases the car’s acceleration. Lower un-sprung weight also makes your ride more comfortable. Another major advantage of this system is its ease of manufacturing as well as low cost of manufacture compared to other stand-alone suspension systems. Without an upper arm, the suspension system designers can directly block vibration from reaching the passenger compartment.

Nevertheless, the MacPherson struts come with their own drawbacks. Being a long, vertical assembly, you would encounter difficulties if you lower your car as they may be collision with the structure of your car. Thus they do not work well with racing cars that are normally lowered. The MacPherson struts also have problems working with wider wheels that have increased scrub radius, where you would need extra effort to navigate your car in this situation. There is also the problem with the small camber change with vertical movement of the suspension, which could mean the tires have less contact with the road during cornering. This could reduce handling abilities of your vehicle.

 

Double Wishbone Suspension System- One of its primary benefits is the increase of negative chamber as a result of the vertical suspension movement of the upper and lower arms. This translates to better stability properties for the car as the tires on the outside maintain more contact with the road surface. Handling performance also increases. The double suspension system is much more rigid and stable than other suspension systems, thus you would realize that your steering and wheel alignments are constant even when undergoing high amounts of stress.

Moving on to the drawbacks of the double wishbone suspension system, it is normally bugged by cost issues as it is a more complicated design to produce. There are many parts to the system, and thus every time any of these malfunction of fail, your whole system fails. Repair, modification and maintenance costs and complexities for double wishbone suspension systems are normally higher due to these reasons. This suspension system also proves to be flexible for design engineers, as the arms of the system can be fixed at different angles to the surface, parameters such as camber gain, roll center height and swing arm length can be determined and designed flexibly to suit and road surface in condition.

As we have seen, both suspension systems have their own plus points and limitations. To conclude, double wishbones may perform better, but the MacPherson struts would prove to be more affordable in the long run.

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Types Of Gear

1. Spur Gear
2. Helical Gear
3. Herringbone Gear
4. Bevel Gear
5. Worm Gear
6. Rack and Pinion
7. Internal and External Gear
8. Face Gear
9. Sprcokets

    1) Spur Gear-Parallel and co-planer shafts connected by gears are called spur gears. The arrangement is called spur gearing.

Spur gears have straight teeth and are parallel to the axis of the wheel. Spur gears are the most common type of gears. The advantages of spur gears are their simplicity in design, economy of manufacture and maintenance, and absence of end thrust. They impose only radial loads on the bearings.

Spur gears are known as slow speed gears. If noise is not a serious design problem, spur gears can be used at almost any speed.

2)     Helical Gear-Helical gears have their teeth inclined to the axis of the shafts in the form of a helix, hence the name helical gears.

These gears are usually thought of as high speed gears. Helical gears can take higher loads than similarly sized spur gears. The motion of helical gears is smoother and quieter than the motion of spur gears.

Single helical gears impose both radial loads and thrust loads on their bearings and so require the use of thrust bearings. The angle of the helix on both the gear and the must be same in magnitude but opposite in direction, i.e., a right hand pinion meshes with a left hand gear.

3)   Herringbone Gear - Herringbone gears resemble two helical gears that have been placed side by side. They are often referred to as "double helicals". In the double helical gears arrangement, the thrusts are counter-balanced. In such double helical gears there is no thrust loading on the bearings.

4)  Bevel/Miter Gear-Intersecting but coplanar shafts connected by gears are called bevel gears. This arrangement is known as bevel gearing. Straight bevel gears can be used on shafts at any angle, but right angle is the most common. Bevel Gears have conical blanks. The teeth of straight bevel gears are tapered in both thickness and tooth height. 

Spiral Bevel gears: In these Spiral Bevel gears, the teeth are oblique. Spiral Bevel gears are quieter and can take up more load as compared to straight bevel gears.

Zero Bevel gear: Zero Bevel gears are similar to straight bevel gears, but their teeth are curved lengthwise. These curved teeth of zero bevel gears are arranged in a manner that the effective spiral angle is zero.

5)      Worm Gear- Worm gears are used to transmit power at 90° and where high reductions are required. The axes of worm gears shafts cross in space. The shafts of worm gears lie in parallel planes and may be skewed at any angle between zero and a right angle.In worm gears, one gear has screw threads. Due to this, worm gears are quiet, vibration free and give a smooth output.Worm gears and worm gear shafts are almost invariably at right angles.

6)      Rack and Pinion- A rack is a toothed bar or rod that can be thought of as a sector gear with an infinitely large radius of curvature. Torque can be converted to linear force by meshing a rack with a pinion: the pinion turns; the rack moves in a straight line. Such a mechanism is used in automobiles to convert the rotation of the steering wheel into the left-to-right motion of the tie rod(s). Racks also feature in the theory of gear geometry, where, for instance, the tooth shape of an interchangeable set of gears may be specified for the rack (infinite radius), and the tooth shapes for gears of particular actual radii then derived from that. The rack and pinion gear type is employed in a rack railway.

7)      Internal & External Gear- An external gear is one with the teeth formed on the outer surface of a cylinder or cone. Conversely, an internal gear is one with the teeth formed on the inner surface of a cylinder or cone. For bevel gears, an internal gear is one with the pitch angle exceeding 90 degrees. Internal gears do not cause direction reversal.

8)      Face Gears- Face gears transmit power at (usually) right angles in a circular motion. Face gears are not very common in industrial application.

9)      Sprockets-Sprockets are used to run chains or belts. They are typically used in conveyor systems.

Gears may also be classified according to the position of axis of shaft:

a.Parallel

  1.Spur Gear

  2.Helical Gear

  3.Rack and Pinion

b. Intersecting

  Bevel Gear

c. Non-intersecting and Non-parallel

  worm and worm gears

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Failure Analysis

• Why ?

As the standards of our industry rise due to increasing globalization and competition, there is an ever growing need for consistency and reliability. Breakdown of any unit, system or equipment is an avoidable and costly occurrence and must be prevented or minimized. Analysis of such failures becomes a resourceful and affordable tool in addressing such unwanted occurrences.

To establish whether the cause of component failure lay on:

a) Service conditions
b) Design considerations
c) Material and its specification
d) Improper processing and assembly procedures or
e)  Combinations of these.

Only the real “Root cause” can ensure the effectiveness of corrective and preventive actions and avoid recurrence of failure..

• Stages Of Failure Analysis

1. Understanding and assimilation of background data and selection of samples.
2. Examination and documentation of the failed part by the following

1. Visual examination of parts, location (if necessary) and relevant photographs as well.

2.  Non destructive testing by means of Radiography, Dye      penetrant, Magnetic particle testing etc. 

3. Mechanical Testing for various physical properties.

3. Vital specimens are selected, classified, and subjected to:

1. Macroscopic examination and analysis. This involves examining the fracture surfaces, secondary cracks, deposits and other such elements
2. Microscopic examination and analysis of fracture surface (by Scanning Electron Microscopy, if required).

4. Chemical analysis of material for conformation to specifications.

5. Chemical analysis of corrosion products, deposits, contaminants etc. 

6. The actual state of the failed part and the failure mode are established.

7.  Fracture mechanics study if found necessary.

8. A simulation of the identical working environment to determine if any external      factors have contributed to the failure

9. Conclusions are determined after compiling all evidences and analysis and       then the report is generated.
10. Follow-up recommendations are also provided.

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Mechanical Engineering-What is It? / What Mechanical Engineers do?

Mechanical engineers design and develop everything you think of as a machine – from supersonic fighter jets to bicycles to toasters. And they influence the design of other products as well – shoes, light bulbs and even doors. Many mechanical engineers specialize in areas such as manufacturing, robotics, automotive/transportation and air conditioning. Others cross over into other disciplines, working on everything from artificial organs to the expanding field of nanotechnology. And some use their mechanical engineering degree as preparation for the practice of medicine and law. The mechanical engineer may design a component, a machine, a system or a process. Mechanical engineers will analyze their design using the principles of motion, energy, and force to insure the product functions safely, efficiently, reliably, and can be manufactured at a competitive cost.

Mechanical engineers  work in the automotive, aerospace, chemical, computer, communication, paper, and power generation  industries. Mechanical engineers will be found in virtually any manufacturing industry. Increasingly, mechanical engineers are needed in the environmental and bio-medical fields. Indeed virtually every product or service in modern life has probably been touched in some way by a mechanical engineer.

 

Design and Dynamic Systems Area

 

This area emphasizes modeling and control of dynamic processes in engineering systems. Current research activity is in engineering acoustics and noise control, NVH, vibrations and modal analysis, system modeling and identification, control systems, system dynamics, computer simulation of material-forming processes, off-line programming of robots, automobile crashworthiness, computer-aided strain analysis, software sensor development, optimal control of automated manufacturing, application of artificial intelligence in interactive design software, environmentally conscious design, and design of orthotic devices for gait rehabilitation. 

Energy Thermo-Fluids Area

Emphasizes thermodynamics, heat transfer, and fluid mechanics. Current research activity is in combustion processes, internal combustion engines, transmissions, heat and mass transfer, fluid mechanics, computational fluid dynamics, and emissions and air quality control. 

Manufacturing/Industrial Area

Current research activity is in metal cutting, metal forming (with specific thrusts in sheet metal deformation), grinding, tribological aspects of forming and machining, computer-aided design of dies for forming metals and polymers, robotics and automation, metrology, data-dependent system analysis, industrial engineering, and environmentally conscious manufacturing. The manufacturing systems engineering program emphasizes the integration of design, materials, computers, and manufacturing with an exposure to business and engineering administration, and is particularly suitable for those who have a bachelor’s degree in mechanical, electrical, metallurgical, or chemical engineering.

Solid Mechanics Area

Emphasizes topics in mechanics and materials science. Current research activity is in mechanics of materials with microstructure, experimental mechanics, plasticity, wave propagation and dynamic fracture, biomechanics, micromechanics, ceramics, crashworthiness, polymer matrix composites, and computational mechanics.

Mechanical Engineers study:

• Statics: How are forces transmitted to and throughout a structure?
• Dynamics: What are the velocities,accelerations and resulting forces for a system in motion?
• Kinematics: How does a mechanism behave as it moves through its range of motion?
• Strength of Materials: Is the component strong enough to support the loads? Is it stiff enough?
• Materials Science: Which material has the optimum properties?
• Thermodynamics : How does energy get converted to useful power? What are the losses?
• Fluid Mechanics: What is the pressure drop due to the fluid flow? What are the aerodynamic drag forces?
• Heat Transfer: How do you calculate heat transfer rates from temperature data?  How do you predict the temperature distributions?
• Manufacturing: What manufacturing processes do you select?
• Machine Design: How do you synthesize all of the above?
• Electrical Circuits: How do you integrate electronic controls into your design?
• Laboratory Methods: How do you make and interpret both thermal and mechanical measurements?
• Vibrations: How do you predict and control vibrations?
• Engineering Economics: How do you estimate manufacturing costs?

Mechanical Engineers can take the following career paths:

• Industry (the most common)
• Graduate School
• Entrepreneur/Business Owner
• Research Labs
• Military
• Government
• Preparation for other Professions (law, medicine, teaching, etc.)

Mechanical Engineers are engaged in the following activities:

• Conceptual design
• Analysis
• Presentations and report writing
• Multidisciplinary teamwork
• Concurrent engineering
• Benchmarking the competition
• Project management
• Prototyping
• Testing
• Measurements
• Data Interpretation
• Developmental design
• Research
• Work with suppliers
• Sales
• Consulting
• Customer service

Skills that help Mechanical Engineers to be successful in their careers:

• Problem solving (The essence of engineering!)
• Creativity
• Hands-on understanding
• Networking
• Leadership/conflict resolution
• Knowledge management

Mechanical Engineering careers can have the following stages:

• Early years – technical work most important
• Middle years – project management and product expert knowledge (still technical) become more important.
• Senior years – corporate, market, and global understanding become important.
• Communication and team skills remain important throughout.

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