What is Dew point

Dew Point:

It is the temperature at which the partial pressure of the water vapour in the mixture is equal to the vapour pressure of water. It can also be defines as, the temperature  where condensate formation will start upon constant cooling of  vapour mixture .

Dew point is a saturation temperature

Dew point is always lower than or equal to the dry bulb temperature.

Dew point is always lower than or equal to the wet-bulb temperature.

At 100% saturation :

Dry bulb temperature = wet bulb temperature = Dew point.

Emission spectroscopy, Absorption spectroscopy, Energy level trasitions

Emission spectroscopy

In emission spectroscopy, sample is subjected to thermal, electrical, or other excitation, and the excited atoms or molecules emit energy as they drop to lower energy levels. The emitted radiation is collected at the detector and its intensity is measure as a function of wavelength.

Absorption spectroscopy

In Absorption spectroscopy, a sample of material to be studied is subjected to radiation in desired part of the spectrum, and the molecules absorb energy, under going transitions to higher energy levels. This results in a series of spectral lines . This radiation is collected at the detector and its intensity is measured.

See Also:

What is a Spectrum ?

What is spectrometer ? what are components of spectrometer ?

What is spectrometer ? what are components of spectrometer ?

Spectrometers are used to observe the spectrum of the energy transition in a sample of interest. Experimental spectrometer contains the following components,

1. Sample: The sample to be detected for spectrum is kept in the sample holder. This sample holder should be transparent to the radiation that we are going to use for the test. For example if we are using UV below 2000 angstroms air becomes opaque in that case we must use a vacuum chamber for the observation.
2. Radiation source: Radiation source is chosen according to sample we are testing. For absorption spectra in the visible and ultraviolet regions older sources were the standard types of continuous light sources: tungsten filament lamps, electric discharges and arcs, spectrum tunable lasers are also available. In emission spectroscopy, the sample is the radiation source. In this the sample is heated, by electric discharge, by radiation or by chemical reaction.
3. Optical system: The optical system is usually used to select or disperse the radiation of different wavelengths and collect it at detectors. Usually, prisms and lenses can be used as optical system. Other systems like, diffraction gratings, dispersing elements can also used.
4. Detector: This is to detect the radiation coming from the sample for intensity measurement. This is designed in such a way that it will record and display the relation between wavelength and intensity. Normally a photographic emulsion is used as a detector. In visible and ultraviolet regions, photosensitive semiconductors are used. In infrared region thermocouples and bolometers are used. In microwave region, crystal diodes are used.

What is a spectrum, spectral lines, Fluorescence spectroscopy

Spectrum:

spectrum is representation of the amount of absorption as a function of wavelength  or frequency. Fluorescence spectroscopy is a process of exciting emission spectra, usually by excitation with radiation. In this process one may measure the distribution of wavelengths of  emitted radiation, as in any other kind of emission spectroscopy.

What is pseudopotential, core electrons, solid structure, method

Pseudopotential:

The property of the solids depend upon the electrons in valence-conduction bands and these electrons which move in the solid are found outside the atomic core. Thus we should concerned about the description of the wave function outside the atomic core. Hence, the pseudo-potential is  one which gives rise to essentially the same wave function outside the atomic core as the original atomic potential.

Pseudo-potential concept is to replace the atomic potentials by a weak potential which gives rise to the same scattering amplitude for the conduction electrons.

What are differences between pipe and tube,Birmingham wire gauge,schedule number

Pipes and tubes are specified in terms of their diameter and wall thickness.

Pipes:

• Heavy walled
• Relatively large in diameter
• comes in moderate lengths (20 to 40 ft)
• Threading is possible
• Pipe walls are rough
• Lengths of pipes are joined by screwed, flanged and welded fittings
• Made by welding , casting, or piercing a billet in a piercing mill
• The wall thickness of the pipe is indicated using schedule number
• Size of the pipe is indicated as nominal diameter

Tubes:

• Thin walled
• Less diameter
• available in the form of coils also, several hundred meters
• Can not be threaded
• Tube walls are smooth
• These are joined by compression fittings, flare fittings, or soldered fittings
• These can be cold drawn
• Tube thickness is indicated using BWG (Birmingham wire gauge) 
• Size of the tube is indicated as outside diameter

What is Differential Distillation, Simple Distillation, Rayleigh distillation,Rayleigh equation, material Balance equation

Differential Distillation:

Simple distillation, also known as Rayleigh distillation or differential distillation, is the most elementary example of batch distillation. In this distillation system, the vapor is removed from the

still during a particular time interval and is condensed in the condenser. The more volatile component is richer in the vapor than in the liquid remaining in the still. Over time, the liquid remaining in the still begins to experience a decline in the concentration of the more volatile component, while the distillate collected in the condenser becomes progressively more enriched in the more volatile component.

Schematic representation of differential distillation is as shown in in fig.1

Fig:1 Differential distillation

No reflux is returned to the still, and no stages or packing materials are provided inside the column; therefore, the various operating approaches are not applicable to this distillation system. The early analysis of this process for a binary system, proposed by Rayleigh is given below. Let F be the initial binary feed to the still (mol) and x_F be the mole fraction of the more volatile component (A) in the feed. Let B be the amount of compound remaining in the still, x_B be the mole fraction of component A in the still, and x_D be the mole fraction of component A in the vapor phase. The differential material balance for component A can then be written as:

x_D dB = d ( B x_B ) = B dx_B + x_B dB

Upon integration:

or

In this simple distillation process, it is assumed that the vapor formed within a short period is in thermodynamic equilibrium with the liquid; hence, the vapor composition (x_D) is related to the liquid composition (x_B) by an equilibrium relation of the form x_D = F(x_B). The exact relationship for a particular mixture may be obtained from a thermodynamic analysis depending on temperature and pressure. For a system following the ideal behavior given by Raoult’s law, the equilibrium relationship between the vapor composition y (or x_D) and liquid composition X (or x_B) of the more volatile component in a binary mixture can be approximated using the concept of constant relative volatility (α), which is given by:

Substitution of the above equation in Equation (2)

Although the analysis of simple distillation historically represents the theoretical start of batch distillation research, a complete separation using this process is impossible unless the relative volatility of the mixture is infinite. Therefore, the application of simple distillation is restricted to laboratory-scale distillation, where high purities are not required, or when the mixture is easily separable.

ISRO question paper, ISRO sample paper, Indian Space Research Organisation, question papers,technical, aptitude, interview pattern, 2009,chemical engineering

1) Special software to create a job queue is called
a) driver
b) spooler
c) interpreter
d) linkage editor
2)When a process is rolled back as a result of deadlock the difficulty arises is
a) Starvation
b) System throughput
c) low device utilisation
d) cycle stealing
3)On receiving an interrupt from an I/O device the CPU
a) Halts for a predefined time.
b) Branches off the interrupt service routine after completion off the current instruction.
c) Branches off to the interrupt service routine immediately.
d) hands over the control of address bus and data bus to the interrupting service.
4) Which of the following is true of the auto increment addressing mode?
1. It is useful in creating sef relocating code.
2)If it is induced in an instruction set architecture , than an additional ALU is required for effective
address calculation.
3) The amount of increment depends on the size of the data item accessed.
a) 1 only.
b)2 only
c) 3 only
d) 2 and 3 only
5) The primary purpose of an operating system is
a) To make the most efficient use of the computer hardware.
b) to allow people to use the computer.
c) To make the system programmers employed.
d) to make computers easy to use.
6)consider the cpu intensive processes which require 10,20,30 time units and arrive at time 0,2,6
respectively.how many context switches are needed if the operating system implements a shortest
remaining time first scheduling algorithm?Do not count the context switches at the time 0 and end.
a) 1
b) 2
c) 3
d) 4
7) consider a system having n resources of the same type.These resources are shared by 3 processes
A,B,C .These have peak demands of 3,4,6 respectively.For what value of n deadlock won't occour.
a) 15
b) 9
c) 10
d) 13
8) In which addressing mode the effective address of the operand is computed by adding a constant
value to the content of the register?
a) absolute mode.
b) indirect mode
c) immediate mode
d) index mode
9)the process of organising the memory into two banks to allow 16 bit and 8 bit data operation is called
a) bank switching
b) indexed mapping
c) two way memory interleaving
d) memory segmentation
10)a one dimensional array A has indices 1-75.Each element is a string and takes up three memory
words. The array is stored in location 1120 decimal. The starting address of A[49] is
a) 1267
b) 1164
c) 1264
d) 1169
11) The micro systems stored in the control memory of a processor have a width of 26 bits. Each
microinstruction is divided into three fields : a microoperation field of 13 bits, a next address field(X),
and a MUX select field(Y). There are 8 status bits in the inputs of the MUX.How many bits are there in
the X and Y fields and what is the size of the control memory in number of words?
a) 10,3,1024
b) 8,5,256
c) 5,8,2048
d) 10,3,512
12)The use of multiple register windows with overlap causes a reduction in the number of memory
accesses for
1.function locals and parameters
2. register saves and restores.
3. instruction fetches.
a) 1 only
b) 2 only
c) 3 only
d) 1,2,and 3
13)Which of the following about relative addressing mode is false?
a) it enables reduced instruction size.
b) it allows indexing of array element with same instruction.
c) it enables easy relocation of data.
d) it enables faster address calculation than absolute addressing.
14)Substitution of values for names (whose values are constants) is done in '
a) local optimisation
b) loop optimisation
c) constant folding
d) strength reduction
15)A root a of eq f(x)=0 can be computed to any degree of accuracy if a good initial approximation x0
is chosen for which
a) f(x0)>0
b) f(x0)f''(x0)>0
c) f(x0)f''(x0)<0
d) f''(x0)>0
16) consider the polynomial p(x)=a0+a1x+a2x*x+a3x*x*x. The mininum number of multiplications needed to evaluate p on an input x is
a) 3
b) 4
c) 6
d) 9
17)Activities which ensure that the software that has been built , is tracable to customer is covered as
part of
a) verification
b) validation
c) maintenance
d) modelling
18) A testing method which is normally used as the acceptance test for a software system is
a) regression testing
b) integration testing
c) unit testing
d) system testing
19)A locked database file cab be
a) accessed by only one user
b) modified by the users with the correct password.
c) used to hide the sensitive information.
d) updated by more than one user

ISRO sample paper, Indian Space Research Organisation, question papers,technical, aptitude, interview pattern, chemical engineering

1 The concept of ---------------------------------- derived from the “ZEROTH LAW OF THERMODYNAMICS”.
TEMPERATURE

2 The concept of ------------------------------------- derived from the “SECOND LAW OF THERMODYNAMICS”.
ENTROPY

3 The expression for isentropic index [?] in terms of number of degrees of freedom

( n ) ------------------------
1+ [ 2 / n]

4 The critical Reynolds no upto which the viscous flow exists in pipe -------------------
2000

5 Two forces of equal magnitude P acts at right angles to each other and having same directions. Find out the expression for their resultant [R ]--------------------
[2]½ P

6 The angular frequency of handclock------------------
?/30 rad/s

7 The equation for free torsional vibration----------------------------
[1/2?] [q/I]½


8 A thin cylinder is subjected to longitudinal stress s0 and internal pressure P , findout the maximum shearstress developed in it [ q max] ------------------------
0.5 s0

9 Rate of moment of momentum is equal to the -------------------------
Torque applied by the body

10 The expression for loss of energy [he ] due to sudden enlargement of the pipe--------
he =[v1-v2]²/2g

11 A spring of stiffness K is divided into “n” number of springs. Each spring having stiffness ---------------------------
nK

12 The non-dimensional number corresponds to
[inertia force\compressibility force]½------------------------------ Euler number

13 Equation for forced vortex flow-----------------------------
v/r = constant

14 The causes of cavitation
Metallic surfaces are damaged
Noise & vibrations

15 How to increase the thermal efficiency in Carnot cycle by-------------------------------
Decreasing low temperature

16 The slenderness ratio in columns can be obtained from the ---------------
Least radius of gyration

17 50:1 gear reduction ratio possible in-----------------
worm gear

18 Wire drawing property named as -------------------------
ductility

19 One man is standing in the elevator and the elevator is moving in the upward direction. What type of reading regarding the weight of man will we get from gauge---------------
The weight of man shown by the gauge will more the actual weight of the man.

20 LMTD for counterflow heat exchanger is compared to parallel to heat exchanger-----
More

21 The free damping equation 2yºº + 3yº +8y =0. Calculate damping factor (D.F )--------
3/8



22 The discharges for the two parallel pipes of same lengths are Q1 & Q2 respectively and their diameters are 200 mm & 800 mm respectively. Calculate the ratio of discharge of smaller pipe to larger pipe.
1/32

23 A compressor is used to compress the air from 5 bar to 10 bar .Calculate its critical pressure [ P?]----------------------
2.64 bar

24 Equivalent twisting moment------------------------------
Te = [T² + M²]½

25 The shear stress distribution in pipe flow -----------------------------
Centre is zero and linearly varying from the center to the wall

26 The irrational component in x-y is--------------
dv/dx = du/dy

27 The ratio kinetic viscosity/thermal diffusivity is -------------
Nusselt Number

28 The cylinder is subjected to insulations K & 2K at the outside surface to avoid heat transfer. In order to arrest heat transfer effectively , which insulation should be provided first at the outer surface?
2K & K respectively

29 The wall having conductivities
K1 K2

Findout the equivalent conductivity of the material--------------------?

29 The maximum amplitude in this vibration equation y = 6 sin?t --------
6

30 The thermal boundary layer in an ideal fluid flow is --------------
0

31 What does tend to stagnation point -----------------------
The velocity is 0 at the stagnation point due to the increase in pressure energy from the conversion of K.E into P.E.
32 Match the following:
i. subsonic nozzle : figure
ii. Supersonic nozzle : figure
iii. Subsonic diffuser : figure
iv. Centrifugal compressor : figure

40 Cold working of metal increases ----------------------
Tensile strength

41 The power absorbed in belt drive depends on-----------------------
Tension in tight side, Tension in slack side, coefficient of friction & Radius of pulley.

42 The temperature loss related -------------- hysteresis loss

43 The convergent pipe having entry and exit diameters are 100 and 50 mm respectively, find out their velocity ratio from entry to exit…………..
1/4

44 They had given one composite circular pipe having 4 varying cross sections . They are 2D, 1.5D, 4D & D respectively. The water is entering at velocity V at section 1 and leaving at section 4. Find out the pressure decreasing order……………
P4>P2>P1>P3

45 The bulb having weight 150N supported by two ropes and attached to the walls having angles 45º & 60º. Findout the reaction forces in the ropes ?
This is related to Lamis theorem
46 A hollow sphere of radius r . A particle is moving with coefficient of friction 1/[3]½ inside the sphere from wall . which height will it become rest?

47 The disc is resting on the rough wall by a rope tied at the center . The rope makes angle with the wall around 30º. The tension in the string is ----------than the weight of the disc. more

48 A railway wagon containing partially full of water. Which angle----------------

49 Findout the graph between discharge [Q] in the x-axis and head [H] in the y-axis----------

50 In welding pitch dimension is limited to----------------------

51 The composition of inconel alloy-------------------

52 There is a heat transfer between two walls having thickness and conductivities k1 & K2 respectively. The linear temperature profile of first wall is more steeper than the second wall . Findout the ratio K1/K2 ---------------------
a) >0 b) <0 c)=0 d) the given data is insufficient

53 The max shear stress developed in solid circular shaet is 100 MPa . Calculate the max normal stress developed in it? ??????



54 This question related to welding -------------

55 Bearing liner-------------------------
a) Babbit metal b) Gun metal

56 Electrical resistance material --------------Nichrome

57 This question related to radiation

58 A sun emits 1150K at 0.5µ. A furnace emits 300k from small door --------------

59 In the simple pendulum , the maximum amplitude depends on ------------------- increase in length

60 The fuel flow increases if-------------------------
a) exhaust valve burnt b) filter choke c) silencer choke

61 The jet propulsion depends on-------------
a) jet velocity b) weight ratio

62 What is the condition for perfect frame-------------------------------------

63 Depth of cut can be increased by-----------------------



64 The workpiece can be held in-----------------

65 This is related toNucleate boiling

66 What is the expression for Reynolds number in terms of diameter of the pipe…………..Re =?VD/µ

67 Air conditioning means---------------
a) cooling & heating b)dehumidifying c) removing impurities from air d)all

68 Fibrous fracture occurs in ------------------------
a)brittle fracture b) ductile fracture c)shear fracture d)none

69 In laser beam machining , the workpiece should be--------------
a)absorbed by all the rays b) reflected by all the rays

70 Foam and coke are good insulators. Why?-----------------------
a)less density b)

71 Gold property------------------
a)good conductor b)good insulator


72 In lathe , the workpiece can be held in --------------------------------------
a) live center b)steady rest c)3-way chuck d)4-way chuck


INTERVIEW PATTERN:I. Project ExplanationII. Fluid Mechanics:i. Define laminar flow & Turbulent flow
ii. What is the value of Reynolds no in pipe flow
iii. What is the significance of Reynolds no
iv. Head losses in pipe
v. Define boundary layer in pipe flow & thickness of boundary layer
vi. What is the variation of d in laminar & turbulent flow
III. Strength of materialsi. Draw the figure for spring damper system
ii. Differential equation for spring damper system
iii. Find out the deflection of spring damper system
iv. Define stiffness and unit of stiffness
IV. Material Sciencei. Ferrous materials
ii. Non-ferrous materials
iii. Define fatigue
iv. Define fatigue resistance?
v. Curve for fatigue
vi. Fatigue limit

IFS Chemical Engineering question paper, 2005, Indian Forest Service, test papers

SECTION A

1. Answer any four of the following:(a) Find the first-order rate constant for the disappearance of A in the gaseous reaction 2A → R, holding the pressure constant, the volume of the reaction mixture starting with 80 per cent A decreases by 20 per cent in 3 mm. (10)

(b) A solution contains 50 per cent benzene, 30 per cent toluene and 20% xylene by weight at 100° C. The vapours are in contact with the solutions. Calculate total pressure and mole per cent composition of liquid and vapour: (10)

(c) Show that the internal energy of an ideal gas is a function of temperature only. (10)
(d) For adiabatic batch reactor, derive an expression to determine the time required to achieve a desired conversion. (10)
(e) Define Bubble point and Dew point. Explain in detail how to calculate bubble point or dew point of given binary mixture. (10)
2. The elementary reaction. A + B → R + S is effected in a set up consisting of a mixed reactor into which two reactant solutions are introduced followed by a PFR. A large enough of excess of B is used so that the reaction is first order w.r.t. A. It is proposed to reverse the order of two units. How does this change affect the conversion? (40)
3. A high purity limestone is burnt in a lime kiln which is fired externally with a coal containing 75.5 per cent C, 5.5 per cent H, 1.6 per cent N, 1.1 per cent S, 7.6 per cent and rest ash. The stack gas analysis is 20.2% CO2, 7.1% O2 and rest N2, Calculate-
(a) kg limestone burnt/kg of coal;
(b) excess air used for combustion. (40)
4. One mole of an ideal gas initially at P1 and T1 is compressed reversibly and adiabatically till the pressure is P2 and then it is cooled at constant volume to the initial pressure, finally the gas is restored to the initial state through an isobaric process. Calculate the work done by the process. (40)

SECTION – B

5. Answer any four of the following:(a) Define depreciation. What are the different methods for determining depriciation? Explain the method, sum of the years digit method. (10)
(b) Explain briefly the factors to be considered for the location of a chemical plant. (10)
(c) Describe the manufacture of caustic soda by either diaphragm or mercury cell process. Discuss the pollution aspects of this industry. (10)
(d) Explain briefly the pollutants emitted from a tanning industry. (10)
(e) Explain the cracking and polymerisation of petroleum fractions. (10)
6. (a) Explain the break-even analysis and its equation. (10)
(b) A Project can produce 12000 units per year at 100 per cent capacity. The variable cost per unit is Rs. 3 at 100 per cent capacity. Fixed costs are Rs. 10,000 per year. Find the break-even point if the selling price is Rs. 5/ unit. Now the manufacturer finds that he can sell only 80% at Rs 5/ unit. How much should he charge for additional units if he brings production upto 100 per cent capacity and increases profits after taxes by an additional amount of Rs. 1,000? Use tax rate for the above problem 52 per cent. . (30)
7. (a) Describe the process with neat flow sheet of the manufacture of ethyl alcohol. (30)(b) Discuss the applications of following products: (10)
(i) Enamel paint (ii) Rancidity.
8. (a) Discuss the methods possible for preventing various industrial hazards. (20)(b) Explain primary treatment method of waste-water treatment. (20)

IFS Chemical Engineering question paper, 2007, Indian Forest Service, test papers

SECTION A

1. Answer any four of the following (Maximum 150 words):
(a) Discuss reversible thermodynamic processes.
(10)
(b) Write short note on fugacity.
(10)
(c) Write short note on reactors in series.
(10)
(d) A solution of naphthalene, C10H8, in benzene, C6 H6, contains 25 mole per cent of
naphthalene. Express the composition of the solution in weight percent.
(10)
(e) A solution of Sodium Chloride in water contains 230 grams of NaCl per liter at 20°C. The
density of solution at this temperature is 1.148 grams per cubic centimeter, calculate :
(i) Volumetric percent of water
(ii) Composition in mole percent
(iii) Modality.
Note : density of water at 20° C = 0.998 g/cc.
2. (a) The liquid phase reaction,
(where K1=8 liter/mol.min
K2=3 liter/mol.min)
is carried out in 150 litre stirred tank reactor under steady state conditions. Reactants A and B
are fed to the reactor at equal volumetric flow rates. The concentrations of A and B streams
are 2.8 mole A/ litre and 1.6 mole B/litre. What should be the flow rate of each stream to get
75% conversion of the limiting reactant?
(25)
(b) Prove that the heat transferred equals the enthalpy change of the system for a mechanically
reversible, constant-volume, constant-pressure, non- flow processes.
(15)
3 (a) A steel casting [Cp = 0.5 kJ kg-1 K-1] weighing 40 kg and at a temperature of 450°C is
quenched in 150 kg of oil [Cp = 2.5 kJ kg-1 K-l at 25°C. If there are no heat losses, what is the
change in entropy of :
(i) the casting,
(ii) the oil and
(iii) both considered together? (25)
(b) Derive the expression for the design equation of tubular reactor. (15)
4. (a) One litre/mm of liquid containing A and B [CA0 = 0.10 mol/litre, CBO =0.01 mol/litre] flow
into a mixed reactor of volume of one litre. The materials react in a complex manner for
which the stoichiometry is unknown. The outlet streak from the reactor contains A, B and
C(CAf = 0.02 mol/litre, Cbt= 0.03 mol/litre, Ccf = 0.04 mol/litre). Find the rate of reaction of
A, B and C for the conditions within the reactor. (20)
(b) Chlorobenzene is nitrated using a mixture of nitric acid and sulphuric acid. During the pilot
plant studies, a charge consisted of 100 kg chlorobenzene (CB), 106.5 kg 65.5% (by weight)
nitric acid and 108 kg 93.6% (by weight) sulphuric acid. After two hours of operation, the
final mixture was analysed. It was found that the final product contained 2% unreacted
chlorobenzene. Also the product distribution was found to be 66% p-nitrochlorobenzene and
34% o-nitrochloro benzene, calculate:
(i) The analysis of charge
(ii) The percentage conversion of chlorobenzene.
(20)

SECTION B

5. Answer any four of the following in brief (Maximum 150 words):
(a) PERT
(10)
(b) Break-even analysis
(10)
(c) Biogas
(10)
(d) Essential oils
(10)
(e) Norms for air emission.
(10)
6. Describe manufacture of ammonia giving neat flow diagram and discuss its major pollution
problems.
(40)
7. (a) Suggest and justi1’ a location for a soda ash plant.
(20)
(b) Discuss greenhouse effect.
(20)
8. (a) Discuss cracking in brief.
(20)
(b) The original value of a piece of equipment is Rs. 22,000. Its salvage value is Rs. 2,000 at the
end of service life of 10 years. Determine the book value of the equipment at the end of 5
years using:
(i) Straight-line method
(ii) Textbook declining-balance method
(iii) Double declining-balance method.

IFS Chemical Engineering question paper, 2004, Indian Forest Service, test papers

SECTION A

1. Answer any four of the following (10 x 4 = 40)
(a) (i) What is time dependent flow ? With the help of this phenomenon, explain the meaning of Thixotropic liquid and Rheopeptic substances.
(ii) Write the power law equation for dilatant and pseudo plastic fluids, and explain the terms ‘flow consistency index’ and ‘flow behaviour index’.
(b) Derive an equation for steady conduction in the radial direction of a hollow cylinder. From the equation, explain the term log-mean radius. Under what condition, can the log-mean radius be replaced by arithmetic mean radius?

(c) In a double pipe heat exchanger, a hot fluid is cooled from 150 to 100°C by using cold water, which is heated from 30 to 50°C. Derive a suitable expression to prove that there is a distinct advantage of using the exchanger in counter-current flow over that of using it in parallel flow.

(d) Explain how thermal condition of feed influences the liquid or vapour flow rate around the feed plate of a rectification column. What common factor can be used for characterizing five different feed conditions? From the value of this common factor, explain the meaning of horizontal and vertical feed lines.

(e) Explain the phenomenon of primary nucleation in the process of crystallization, and illustrate the difference between homogeneous and heterogeneous nucleation.

2. (a) For an incompressible fluid, write the Bernoulli equation for fractionizes flow. What correction would you apply for incorporating fluid friction? Explain the difference between skin friction and form friction. (10)

(b) What is terminal velocity? Write the equation for terminal velocity for the flow of a single particle through a fluid under the action of (i) gravity and (ii) centrifugal force. How is the equation for terminal velocity under free settling condition modified for hindered settling conditions? (10)

(c) What is a ball mill? Derive an equation for the critical speed of a ball mill. (10)(d) What is a venture meter? Describe the principle of working of a venture meter and write an expression for the venture coefficient. (10)

3. (a) An air water system has a dry bulb temperature of 65.5°C and a wet bulb temperature of 54.5°C.
(i) If the air is cooled to 37.8°C, what per cent of the moisture will condense?
(ii) If the air is again heated to 65.5°C, how much heat will be required per kg of dry air? Specific heat of air = 0.23 kcal/ (kg 0C). (10)
(b) A spherical particle of ethanol of 10 mm diameter is evaporating in an air stream at 26°C. The thickness of the stagnant air surrounding the particle is 1.5 mm. Vapour pressure of ethanol at 26°C is 60 mm Hg and the mole fraction of ethanol in the main stream of the air is 0.005. The diffusion coefficient of ethanol in air is 1.04 × 10-5 m2/sec and the value of R is 82.06 × 10-3 m3 atm/kg mole. Determine,
(i) The mole fraction of ethanol at different positions across the stagnant layer.
(ii) Rate of evaporation of the particle per second. (10)
(c) What are different types of packing that are used in an absorption tower? Explain a simple procedure for calculating the height of a packed tower for absorption of a single component from a gas mixture. (10)
(d) What is critical moisture content? Describe the method for drying of a wet solid before it reaches the critical moisture content. (10)
4. (a) Develop a relation between heat transfer and fluid friction by using the Reynolds’s Analogy. (10)
(b) (i) What is a radiation shield? How does it help in reducing radiant heat loss?
(ii) A double walled spherical container is used for storing liquid oxygen. The diameter of the inner and outer walls of the container is 30 cm and 36 cm, respectively. The surfaces of both the spheres are plated, so that their emissivity is 0.05. Determine the rate at which oxygen will evaporate at -183°C, when the outer wall of the sphere ismaintained at 20°C. Latent heat of evaporation of oxygen is 57.2 kcal/kg. (5 + 5)

(c) What are drop wise and film wise condensation? Mention the conditions that favour drop wise condensation. Describe how the heat transfer coefficient in a vertical condenser is influenced by the height of the condenser. (10)

(d) What is effectiveness of a heat exchanger? Derive a relation between the effectiveness and number of transfer units for a countercurrent heat exchanger. (10)

SECTION B

5. Answer any four of the following (10 × 4 = 40)(a) What are the relative advantages and disadvantages of the proportional, integral and derivative control actions? What are their characteristic effects on the closed loop response for a process?

(b) Explain briefly the essential elements of a computer controlled process system.
(c) What is reverse osmosis? How can it be used for the separation of a solute from an aqueous solution?
(d) What is molecular distillation? With a neat sketch describe the working of a molecular distillation unit.
(e) Discuss how wind load is taken care of in the design of a tall vertical vessel.
6. (a) Illustrate the principle of separation of gases by using non-porous membrane. (10) (b) Discuss about electrolytic regeneration of mixed bed ion exchange resins. (10)
(c) Explain the process of diffusion dialysis and mention its applications. (10)
(d) What are absorption and extraction type separation processes? Illustrate them with examples. (10)
7. (a) Discuss how to find the frequency response of a proportional + integral controller, (10)(b) Explain how a strain gauge is used for pressure measurement. (10)(c) Illustrate the process of feed forward control. (10)(d) Write a relationship that will give the molar or specific enthalpy of a multi-component liquid at temperature T, with known composition for N components. What are the principal control considerations that affect the scope of mathematical modeling of a chemical process? (10)

8. (a) Illustrate the method for the design of a conical head of a cylindrical pressure vessel. (10)
(b) Discuss about major loads and subsidiary loads that must be considered for the design of a pressure vessel. (10)
(c) What are skirt supports? Discuss the method for calculating the thickness of a skirt support. (10)
(d) Discuss the method for calculating the thickness of the shell of a thin wall pressure vessel. (10)

IFS Chemical Engineering question paper, 2006, Indian Forest Service, test papers

SECTION A

1. Answer any four of the following (in 150 words, maximum)(a) Discuss about proximate analysis of coal. (10)
(b) Discuss about Mollier diagrams. (10)
(c) An aqueous solution contains 40% Na2CO3 by weight. Express the composition in mole per cent. (10)
(d) A natural gas has the following composition, in volumetric per cent: Calculate:-
(i) Composition in mole per cent.
(ii) Composition in weight per cent. (10)
(e) Discuss the mathematical statement of second law of thermodynamics. (10)
2. (a) Mono-chloroacetic acid (MCA) is manufactured in a semi batch reactor by the action of glacial acetic acid with chlorine gas at 373 K in the presence of PC13 catalyst. MCA thus formed will further react with chlorine to form dichloroacetic acid (DCA). To prevent the formation of DCA, excess acetic acid is used. A small-scale unit, producing 5000 kg/d MCA, requires 4536 kg/d of chlorine gas. Also, 263 kg/d of DCA is separated in the crystallizer to get almost pure MCA product. Find the % conversion, % yield of MCA and selectivity. (25)

(b) Discuss about the heat of reaction. (15)

3. (a) For the reaction A → R, K = 0.02 min. It is desired to produce 4752 g moles of R per 10 hours a day and 99% of A entering the reactor is to be converted in a batch reactor. To charge the reactor and heat it to reaction temperature requires 0.26 hours. To discharge the reactor and to prepare it for the next run takes 0.9 hours. Calculate the volume of the reactor required. Pure A with molar density of 8 g mole per liter is charged to the reactor. (25)

(b) Discuss about phase rule. (15)

4. (a) Discuss ideal solution and its properties. (20)(b) Derive an expression for design equation for an ideal batch reactor. (20)

SECTION B

5. Write short notes on any four of the following (in 150 words, maximum)(a) PVC (10)
(b) Principles of piping layout (10)
(c) Coal chemicals (10)
(d) Alternative investments (10)
(e) Effects of air pollution (10)
6. (a) Describe the manufacture of penicillin using fermentation route. (20)(b) List the mathematical methods for profitability evaluation and describe any one. (20)
7. List various environmental protection laws and give the main features/provisions of any four in brief. (40)
8. (a) Discuss the estimation of capital investment. (20)(b) Discuss petroleum refining briefly. (20)

IFS Chemical Engineering question paper, 2005, Indian Forest Service, test papers

SECTION A

1. Answer any four of the following (4 x 10 = 40)
(a) What is Bernoulli equation? Determine it for the flow of a compressible fluid in a pipeline.(b) Discuss, with the help of a sketch, the principle of steam jet ejector for creating vacuum.(c) Explain the mechanism of heat transfer in nucleate pool boiling of liquids.(d) Discuss penetration theory of mass transfer. How does it differ from surface renewal theory?(e) Describe the construction and working of a Swenson-Walker crystallizer.
2. (a) Discuss differential and cumulative methods of screen analysis. (10)(b) Explain the construction and operation of a plate and frame filter press. (10)(c) What is area meter? Explain its operation. (10)(d) Determine an expression for terminal velocity of solid particles settling freely in a fluid stream. Modify the above expression for the case of hindered settling. (10)

3. (a) Differentiate between free and forced convection. Describe the procedure to calculate heat transfer coefficient under free convection. (10)(b) Explain effectiveness of a heat exchanger. Obtain its expression for a parallel flow heat exchanger in terms of NTU and capacity ratio. (10)(c) Discuss the effect of boiling point elevation on the capacity of an evaporator. (10)(d) Define emissivity of a body. How is it related to absorptivity? (10)
4. (a) Derive Rayleigh equation for differential distillation of a binary system. (10)(b) Discuss pressure drop characteristics of packed columns and explain the significance of flooding point. (10)(c) Explain the mechanism of moisture movement during drying of a solid. (10)(d) Briefly explain the construction and operation of a packed extraction tower. (10)

SECTION B

5. Answer any four of the following (4 x 10 = 40)(a) Explain the concept of cross flow micro filtration along with its advantages over conventional filtration.
(b) Name various types of heads commonly used in cylindrical vessels. Draw their sketches and list areas of applications.
(c) Mention stepwise procedure for the design of a torispherical head for a cylindrical vessel.
(d) What is final value theorem? How is it used to determine response of a system? Explain it with suitable examples.
(e) Discuss cascade control and its application in process industries.

6. (a) Describe procedure of immersion precipitation process for the production of membranes. (10)
(b) Explain, with the aid of a sketch, the working of an electro dialysis. (10)(c) What is pervaporation? Explain it with the help of a neat sketch and also indicate areas of its application. (10)(d) Discuss ion-exchange separation process for the demineralization of water. (10)
7. An autoclave of 7.9 m3 volume capacity has ellipsoidal heads (major to minor axis ratio = 2:1) at its top and bottom ends. The autoclave is subjected to a maximum pressure of 8 MN/m2. The allowable stress of the material (carbon steel) is 1040 MN/m2. Weld joint efficiency is 85 per cent. Determine optimum dimensions of the autoclave if the following cost ratios are applicable:
(a) The cost of fabricated shell is estimated to vary inversely with D”4 where D is the inside diameter of the autoclave.
(b) The fabricated cost of top and bottom heads per unit weight is 1.5 times the fabricated cost of shell per unit weight. A 12 mm plate is available in store. Check if it can be used for the fabrication of shell of the autoclave. Alternatively, suggest the suitable thickness of plate required for the fabrication of shell of the autoclave. (40)

8. (a) What are phase margin and gain margin? Discuss their utility in control tunnings. (10)(b) Discuss procedure for plotting of open loop transfer function by root locus method. (10)(c) How do you measure liquid level if the liquid contains suspended solid particles? Suggest measuring instrument along with the principle of working. (10)(d) Explain elements of a computer control system. (10)

IFS Chemical Engineering question paper, 2007, Indian Forest Service, test papers

SECTION A

1. Answer any four of the following (10 × 4 = 40)(a) (i) How is friction factor defined and what are the parameters on which it is dependent? (5)
(ii) What are the different types of conveyers available for bulk solid transportation? (5)
(b) Distinguish between ‘Adiabatic Saturation Temperature’ and ‘Wet Bulb temperature’. Explain why both these are same for air-water system. (10)
(c) Discuss caking of crystals and its prevention. (10)
(d) Distinguish between resistances in series and resistances in parallel through which heat is being conducted under steady-state condition. Explain using electrical analogy. (10)
(e) Differentiate among nucleate boiling, pool boiling and subcooled boiling. (10)
2. (a) How do you use stress-strain relationship to explain the rheological classification of fluids? Explain with examples. (10)(b) Derive the continuity equation. State the assumptions. (10)
(c) (i) List the advantages and disadvantages of plate and frame filter press. (5)
(ii) State the two laws of crushing and write suitable mathematical relationships for the two laws. (5)
(d) (i) Explain the basis for the selection of mixing impellers. (5)
(ii) Briefly explain the mechanism of fluidization. (5)
3. (a) (i) Bring out clearly the concept of film transfer coefficient and overall transfer coefficient in mass transfer. (5)
(ii) Explain briefly the diffusivity of gases and liquids. (5)
(b) (i) Discuss the mass transfer resistances in a wetted column. (5)
(ii) Write briefly on Shank system of leaching. (5)
(c) With a neat drying rate curve, explain different zones of drying. (10)(d) What a1e the limitations of McCa1e-Thiele method? How are these overcome in Ponchon- Savarit method? (10)
4. (a) (i) What is LMTD, and why and where is it used? (5)
(ii) Obtain the relationship between individual and overall heat transfer coefficients. (5)
(b) (i) State and explain the Stefan-Boltzmann law of radiation.  (5)
(ii) Write a note on absorption of radiation by opaque solids. (5)
(c) (i) What is the influence of boiling point elevation on evaporator performance? (5)
(ii) Briefly describe a vapour compression evaporator. (5)
(d) Write the design procedure for a double pipe heat exchanger. (10)

SECTION B

5. Answer any four of the following (10 × 4 = 40)(a) Explain the principle, of reverse osmosis. What are its limitations and applications? (10)
(b) List out the factors to be considered in the design of vessels. (10)
(c) Name the different supports used for process vessels mentioning their advantages and disadvantages. (10)
(d) Explain with sketches the working principles, installation and applications of thermocouples for temperature measurement. (10)
(e) Explain the working of a PID control system. Draw a pneumatic control circuit for this system and explain the characteristics. (10)
6. (a) Explain the principle of ultra filtration and list out its industrial applications. (10)(b) Discuss the industrial applications of ion exchange process. (10)(c) Explain any two methods for separating a binary liquid mixture stating the underlying principles. (10)(d) Explain the working of an instrument based on electro dialysis. (10)
7. (a) Explain the design equations for calculating the thickness of cylindrical and spherical shells. How will you select a standard plate for fabricating a shell? (10)(b) Write down the stepwise procedure for the design of an elliptical head. (10)(c) Name the different stresses acting on a tall vessel which is to be installed in a seismic zone. (10)(d) Mention any five industrially important alloys of Nickel and Copper. Give their approximate composition and application. (10)
8. (a) With a neat diagram, describe the radioactive vacuum gauge method for measuring pressrue in a process industry. (10)(b) Sketch the following function and obtain the Laplace transform. (10)
(c) (i) Explain in practical terms, how one tunes a feedback controller for an existing process in a chemical plant. (5)
(ii) Define phase margin and gain margin, and show how you can compute them from Bode Plot. (5)
(d) Develop a transfer function between the pressure drop and the manometer reading h for a mercury manometer. List the assumptions made. (10)

IFS Chemical Engineering question paper, 2007, Indian Forest Service, test papers

SECTION A

1. Answer any four of the following :
(10 × 4 = 40)
(a) Prove that the velocity profile in a laminar flow of a Newtonian fluid through a circular pipe
is a parabola.
(b) (i) Differentiate between differential and cumulative analysis to find the average size of
the sample.
(ii) Derive the expression for the critical speed of a ball mill. Mention the meanings of
symbols and their units clearly.
(c) Define humidification and dehumidification, Explain the working of a water cooling tower
with a neat diagram.
(d) Derive the relation between rate of heat transfer and resistances in series in a composite wall.
2. (a) Starting from the first principles, obtain Bernoulli’s equation from momentum balance in
potential flow and extend the equation for practical applications.
(10)
(b) Define capacity and effectiveness of a screen. Derive an expression for the overall
effectiveness of a screen.
(10)
(c) Explain different types of fluidisation and their applications.
(10)
(d) Give a critical account of Rittinger’s and Bond’s laws.
(10)
3. (a) Explain the mechanism of drying during the constant rate and failing rate periods. Discuss the
effects of humidity and velocity of the gas on drying rate.
(10)
(b) Mention the various types of crystallisation equipment used in the process industry. Explain
the working of any one of the crystallisers with a neat diagram.
(10)
(c) Write the suitable conditions for liquid- liquid extraction. Discuss the importance of
equilibrium distribution coefficient and selectivity in the choice of a solvent.
(10)
(d) Write the procedure in detail for the design of a distillation column by Mc Cabe-Thiele
method.
(10)

4. (a) Discuss briefly the various regimes in boiling heat transfer.
(10)
(b) Describe the construction of shell and tube heat exchanger with a neat sketch.
(10)
(c) Define the capacity and steam economy of an evaporator. Discuss the effect of boiling point
elevation on evaporator performance.
(10)
(d) Air is heated in air heather from 30° C to 110°C and the hot gases are cooled from 210° C to
145°C. calculate the LMTD in parallel and counter glows. Give critical comments of the
values obtained.
(10)
SECTION B

5. Answer any four of the following:
(10 × 4 = 40)
(a) Discuss various types of membranes.
(b) Write the design procedure of either torispherical head or elliptical head.
(c) Mention the principal stresses induced in a vessel. How they act over the vessel.
(d) Differentiate between pneumatic and electronic controllers.
(e) List the various liquid level measuring instruments. Give their range and applications.
6. (a) Compare and contrast the terms— osmosis” and “reverge osmosis”.
(10)
(b) Discuss the principles of ultrafiltration. Mention its applications.
(10)
(c) Describe the processes of dialysis and also of electrodialysis. Write their applications.
(10)
(d) Briefly discuss about “Super critical fluid extraction”.
(10)
7. (a) Discuss the selection of material of construction for pressure vessels.
(10)
(b) Explain the design procedure for vertical type storage vessels.
(c) Mention various types of heads commonly used in cylindrical vessels and list their
applications.
(10)
(d) Define joint efficiency. Mention the factors influencing the choice of supports.
(10)
8. (a) Explain the working principles involved in various pressure measuring instruments.
(10)
(b) (i) Explain the negative and positive feedback control system.
(5)
(ii) Explain the servo and regulatory control problems.
(5)
(c) What are the elements of computer based process control? Explain their functions.
(10)
(d) What are phase and gain margins? Discuss the bode stability criterion.

What is aliquid and its properties

Liquid is defined as a material which will take the shape of the container. It is one of the three classical states of matter.

Examples: water, ethanol, most of the organic solvents.

Liquids tend to have better thermal conductivity than gases, and the ability to flow makes a liquid suitable for removing excess heat from mechanical components. The heat can be removed by channelling the liquid through a heat exchanger, such as a radiator, or the heat can be removed with the liquid during evaporation

Liquid is the primary component of hydraulic systems, which take advantage of Pascal's law to provide fluid power. Devices such as pumps and waterwheels have been used to change liquid motion into mechanical work since ancient times. Oils are forced through hydraulic pumps, which transmit this force to hydraulic cylinders. Hydraulics can be found in many applications, such as automotive brakes and transmissions, heavy equipment, and air-plane control systems. Various hydraulic presses are used extensively in repair and manufacturing, for lifting, pressing, clamping and forming

Mechanical properties:

Volume:  Commonly liquids are measured in the units of volume. SI units for volume are m³.

Pressure:
Hydrostatic head is the main property of the liquid. This hydrostatic head is calculated as P= h*rho*g. h = height of the liquid column, rho = density of the liquid, g = acceleration due to gravity.

EIL Aptitude paper 2, Engineers India Limited, question paper, Electrical, Electronics technical paper, with aptitude

Technical section:



1) Bucholz relay is..................
a. Gas actuated relay
b. Current sensing device
c. Voltage sensing device
Ans: a



2)Shunt is made up of .........
a. Copper
b. Tungsten
c. Maganin
Ans: c



3)In a 4kva ,400/200 v m/c the value of impedance & reactance are given as 0.002 & 0.006 .what will
be the new values of them when referred to the h.v side.
a. 0.2,0.6
b. 0.08,0.036
c. 0.4,0.12



4)Metallic sheath is used to .........
a. prevent the cable from moisture
b. provide mechanical strength
Ans: b



5) Of the following bridges the one which can be used for the measurement of dielectric loss of a
capacitor is –
a. Schering bridge ..........
b.Heaviside campbell equal ratio voltage
c. Owen bridge
d. Anderson bridge
Ans. a. Schering bridge



6)Diac is a...............
a. 3-layer ,2-junction
b. 2-layer,3-junction
c. 4-layer,3-junction



7)Load voltage equation of step up chopper.........
a. v(1-a)
b. v/(1-a)
Ans: b



8)Which is not realated to ckt breaker.........
a. conservator
b. explosion pot
c. operating mechanism
Ans: a



9) Coefficient of reflection of short transmission line is........
a. 1
b. -1
c. 0
d. infinite
Ans: b



10)1st nuclear power plant located at .......
a. trombay
b. kalpakkam
c. tarapur
Ans: tarapur



11)If a current setting is given as 25%, ct ratio is 400/5 then find pick up value......
a. 6.25
b. 0.25
c. 4
Ans: a



12. d.c chopper converts .......
a. ac to ac
b. ac to dc
c. dc to dc
d. dc to ac
Ans:c



13)In a controlled rectifier , the nature of load current i.e, whether load current is continous or
discontinous is
a. does not depend on type of load & firing angle delay
b. depends on load & firing angle delay
c. depends only on type of load
d. depends only on firing angle delay
Ans:b



14)For thyrister pulse triggering is preferred on dc trigerring because..........
a. gate dissipation is low
b. pulse system is simpler
c. triggering system is required for very short duration
d. all of these
Ans:d



15)Thyristers are basically ..........
a. scr’s
b. triac’s
c. both scr’s and triac’s
d. all pnpn devices
Ans : d



Non tech section
The nontech section comprises of only g.k questions
1)Vijay singh, who is golf player belongs to .................
a. maritus
b. Maldives
c. Kenya



2)LTTE associated with...........
a. Bangladesh
b. Bhutan
c. shrilanka
d. Nepal
Ans:a



3)S.Sainath related to.........
a. journalism
b. t.v hosting



4)OPEC ‘s headquarter is located at ...............
a. Vienna
b. gienna
c. maxico
Ans:a



5)Jawaharlal Nehru award given to which country...........
a. mexico
b. u.s.a



6)Which contry first started carbon tax...........
7)Nobel prize is equivalent to
a. raman magsasse
b. abel prize



8)The book “the elephant ,tiger and the cell phone is written by
a. Amartya Sen



9)First women leader of INC was
a. Anne becent
b.Sarojini naidu
Ans:a



10)The book Anand math is written by.............
a.B.C Chatterji
b. Rabindranath tagorre



11)APJ abdul kalam associated with..........
a. gslv
b. pslv
c. slv
12)Nilgiri hills is famous for ..........
a. tea
b. coffee
c. rubber
d. spices



13)Olympic 2012 are going to be held at
a. London
b. Bejieng
Ans: London



14)The sentence ‘the way the wind flows ‘means........
a. how the things are
b. how the things are made
c. how we make the things



15)I hope that u _______ come for a cup of tea tomarrow
a. shall be
b. would be
c. will be



16)Pongal is a festival of
a. Karnatka
b. Andra Pradesh
c. West Bengal
d. Tamil nadu



17)Tajmahal was to be built originally at.........
a. M.P
b. Orissa
c. West Bengal
c. Rajasthan



18)Pravasi bhartiya divas was celebrated on........
a. 9 jan
b. 16 april
Ans:a
19)Kajiranga national park is famous for........
a. ryhno
b. lion
c. deer
Ans: a