Machine Drawing next Important questions[mech. engg.]

Important Definitions

31. Roughness width cut off :  The distance used to find the arithmetical average deviation is called the roughness width cut off.

32.Waviness :  It may be defined as the surface irregularities in the form of waves having larger wavelength.

33. Waviness height : It is the distance from the peak of the wave to its valley. It is measured in millimeters.

34. Waviness width : It is the spacing between the successive waves. It is measured in millimeters.

35.  Lay : Lay is the primary direction of the surface pattern prepared by machine tool marks.

36.  Flaws : They occur at random places on a machine component. These are cracks & scratches.

 37.  Ideal surface : It is a hypothetical perfect surface without any micro irregularity.

38.  Actual surface : It is defined as surface of a part which actually is received after machining surface.

39.  Nominal surface : A nominal surface is theoretical, geometrically perfect surface which is not to exist in the general practice.

40. Actual Profile :  It is the actual surface obtained by a manufacturing process.

41. Datum Profile : The profiles which passes through the lowest points of actual profile is called Datum profile.

42. Mean Profile : The profiles which passes  through the actual profile in such a way that the filled up areas between mean profile & actual profile is equal to the areas of voids between mean profile & actual  profile within sampling length.

43. What is reference profile?

Ans 43: The profile which passes through the highest points of actual profile is called reference profile.

44. What do you mean by peak to valley height?

Ans 44: It is the distance between reference profile & datum profile.

45. Define mean roughness index.

Ans45: It is the arithmetic mean of absolute values of heights of peaks or depth of valleys.

46. Define surface roughness number.

Ans 46: It is the average departure of machined surface over a sampling length which is generally taken as 800 microns.

47. Draw the basic symbols of surface roughness.

48. Define coupling.

Ans 48: It may be defined as the joining of two or more pieces of shafts in – order to obtain large length.

49. Where is Oldham’s Coupling best suited?

Ans 49: It is best suited to connect the shafts whose axes are parallel, but not in alignment.

50. Which  material is used for Oldham’s Coupling?

Ans 50: Shafts – Mild Steel

              Flanges & Disc – Cast Iron

              Keys – Mild Steel

51. Draw roughness symbols with values & grade numbers.

VFD (Variable Frequency Drive) [power electronics]

Variable-Frequency Drive (VFD)            [Power Electronics]

#  Variable Frequency Drive (VFD):-

                                                                           A variable- frequency  (VFD) is a system for controlling the rational speed of an A.C motor by controlling The frequency   of electric power supplied to the motor. 

It is also known as Adjustable- frequency drives (AFD) variable – speed drives (VSD), AC drives ,inverter drives.

Operating  Principle:

                                        The synchronous speed of  an AC motor is determined by the frequency of AC supply and number of poles in the stator winding. Thus the Synchronous motor operates at the synchronous speed determined by this equation.

                     Speed in RPM  =  120  X   f

                                                           P

Where, f  be the frequency of AC supply.

                      P = Number of poles in stator winding.

Hence , speed of motor can be controlled by varying frequency of power supplied to motor.

VFD S ystem Description:

                                                 A VFD system consists of an AC motor, a controller and an operator interface as shown in figure:-

VFD Motor:  VFD system consists of 3-Φ induction motor. Mostly, Induction motors are preferred than synchronous motor. Because induction motor are suitable for controlling and is cheap.

VFD Controller :-  It is a solid state  electronic power conversion  device which first convert  AC power in to DC intermediate by using bridge rectifier. This DC power  is then converted in to quasi- sinusoidal AC power using an inverter circuit.

 VFD Operator Interface:-    An operator interface is used to start and stop the motor and to adjust the operating speed.

                              This VFD operating interface  consists of an keypad, display, indication lights and meters to provide information about the operation of the drive. Motor can be  controlled and monitored on computer by using an serial communication part on VFD operator interface .

 VFD Operation :-  When VFD starts ,the applied frequency  and voltage are increased at a controlled rate or ramped up to accelerate the load without drawing excessive current.

               This starting method allows a motor to develop 150% of its rated torque while drawing only 50% of its rated current.

        When a motor is switched ON at full voltage, initially it have at least 300% of its rated current.  While it produce less then 50% of its rated torque.

        As load accelerates, the  available torque usually decrease very little and then increases to a peak while the current remains very high until the motor get full speed.

              By using VFD system, the frequency & voltage applied to the motor  are ramped down at a controlled rate.

              When frequency becomes zero, the motor is shut-off. A small amount of breaking torque is available to help decelerate the load.

                Thus the speed of AC motor can be controlled by varying  frequency of power applied to the motor.

Machine Drawing Notes (Mechanical Engineering)

Machine Drawing               (Mechanical Engineering)

Very-Very important questions to get sure success which covered complete syllabus

Q1: Define basic size?

Ans1: Basic size is that size of a components on which great or less size of a component can be measured.

Q2: Define Limit?

Ans2: It is the higest  and lower limit of a size of a component . The higest size is called high limit of the lowest size is known as low limit.

Q3:

Ans3:  Basic size +20mm

          Maximum  limit of size =20+0.005 +20.005mm(Max. limit)

          Minimum Limit of size =20-0.004=19.996mm(Mini. Limit)

Q4: Define Tolerance?

Ans4: It is the difference between maximum & minimum size of a machine part .Tolerance is the difference between high limit & low limit of a size of a component.

Q5: Calculate the tolerance of the following?

                   Basic size  =  80+0.002

Ans5:  Tolerance= High limit - Low limit

                             = 80.002-79.998 = 0.004 mm

Q6: What are the types of tolerance?

Ans6: Tolerances are of two types:-

i)                    Unilateral Tolerance:- This tolerance is given on one side of the basic size.

 For example-

i)                    Bilateral Tolerance:- In this system the tolerance is given on both the sides of the basic size.

For example-

Q7: Define allowance?

Ans7:  The difference between the dimension of two mating ports is called allowance. It is of two types

i)                    Maximum Allowance:- It is the difference between the  maximum size of the hole & minimum size of the shaft.

ii)                  Minimum Allowance:-  It is the difference between the  maximum size of the shaft & minimum size of the hole.

Q8: Given, i) The maximum hole size =  30.099 mm and minimum shaft size = 30.050 mm. calculate the maximum allowance?

(ii). The maximum hole size =  30.075 mm and minimum shaft size = 30.060 mm. calculate the minimum allowance?

Ans8:  i)  Maximum allowance = 30.099 – 30.050 = 0.049 mm

ii). Minimum Allowance = 30.075 – 30.060 = 0.015 mm

Q9: Define FIT.

Ans9: The assembly of two mating parts is called Fit.

Q10: Write different type of Fits?

Ans10: 1) Clearance Fit:- In clearance fit , shaft is smaller than hole. This type of fits gives loose fitting. There must be some degree of freedom between a shaft & a hole.

2) Interference Fit:- In interference Fit, there is always a negative allowance between the largest hole size & the smallest shaft size. In this fit, the shaft is always larger than the hole.

3) Transition Fit:- In this type of Fits, the fit may be either clearance fit or interference fit. Any pair of parts mating with transition fit may fit with interference while on other pair with the same fit have a clearance fit.

Q11: Define Deviation.

Ans11: It is defined as the difference between actual size or Limit sizes, either maximum or minimum, and the corresponding basic size.

Q12:Define actual deviation?

Ans12: It is the algebraic difference between the actual measured size & corresponding basic size.

Q13: Define upper deviation?

Ans13:  The algebraic difference between the maximum limit of a size & the corresponding basic size.

Q14: Define lower deviation?

Ans14:  The algebraic difference between the minimum limit of a size & the corresponding basic size.

figure:deviation

Q15: Define zero line.

Ans15: Zero line is the line of zero deviation and represents the basic size.

Q16: Define tolerance Zone.

Ans16: Tolerance Zone is the algebraic difference between maximum limit of size & minimum limit of size.In other words, tolerance zone is the algebraic difference between upper deviation & lower deviation.

Q17: Define functional Deviation.

Ans17: Functional deviation is the upper or lower deviation which is closest to basic size.

Q18: Define hole basis system.

Ans18: It is the standard system of  limits & fits. The size of the hole is kept constant & the size of the shaft is kept variable to get the different types of fits is known as hole basis system. The symbol ‘H’ is a fundamental deviation is selected for the holes, when the hole basis system is follows.

Q19: Define shaft basis system.

Ans 19: When the sizes of the shaft is kept sonstant in a standard system of limits & fits, and variations given to the hole for obtaining different types of fits, is known as shaft basis system. The fundamental deviation symbol ‘H’ is selected for shaft basis.

Q20: Define fundamental tolerance .

Ans20: This is also known as grade of Tolerance in Indian Standard System, there are 18 grade of tolerances represented by number symbols both for hole and shaft such as ITOI, ITO, IT1 to IT16. A high number gives a large tolerance zone . fundamental tolerance are indicated for sizes ranging upto 525 mm.

Q21: Define Limit System?

Ans21: The system in which deviations are accepted are called limit system.

Q22: Define standardization.

Ans22:  Standardisation means the size of a machine element accepted nationally or internationally.

Q23: What do you mean by H7/g6?

Ans23: It is sliding fit. Its application are in clutches & shafts.

Q24: What do you mean by φ25 H8 u7?

Ans24:  Basic size = 25 mm

H8 means an h hole to tolerance grade 8.

 u7 means a u shaft to tolerance grade 7.

Q25: Define clearance.

Ans25: It is defined as the difference between the dimensions of  the hole & the shaft assigned intentionally to obtain a particular type of fit. It may be positive or negative when the shaft size is smaller than the hole size, it will be positive & when the shaft size is bigger than the hole , it will be negative.

 Maximum Clearance:- It is the difference between maximum hole & minimum shaft.

Minimum clearance:- In clearance fit, the minimum clearance is the difference between the minimum hole & the maximum shaft.

figure: Clearance

Q  26:Define Interferance.

Ans26: The  negative difference between the size of the hole & shaft before its assembly in made.

Q27: If the size of the hole is 40.02,  40.00 and the size of shaft is 39.96,  39.94 . Find (i) Hole tolerance   (ii) shaft tolerance   (iii) allowance?

Ans27:  (i) Hole tolerance = Maximum limit – Minimum limit

                                            = 40.02 - 40.00 = 0.02 mm

(ii) shaft tolerance =  max. limit – min.limit= 39.96 – 39.94 = 0.02 mm

(iii) Allowance = min. size of hole – max size of shaft = 40.00 – 39.96 = 0.04 mm

Q28: Define surface roughness.

Ans28:  Surface roughness may be defined as the fine irregularities in the surface texture.

Q29: Define Roughness height?

Ans29: It is also known as roughness average (Ra) is an arithmetical average of the roughness deviation.

Q30: Define roughness width.

Ans30: It is the distance parallel to the nominal surface between the two successive peaks, which constitute the predominant pattern of the roughness. It is measured in millimeter.

Major Project Report of Multistory Building( civil engineering)

Multistory Building project :-
                                                    This project is very helpfull for final year students of Civil Engineering which contains all the specifications as wll as cost of material.
This is a Complete Project in word format.

Project Report contains:
-Parts of Building
-Components of Building
-Material Used in Construction
-General specification
- EATH WORK IN EXCAVATION OF FOUNDATION:
-Brick Work
- SNOWCEM WASHING
-STRUCTURAL DESIGN & ITS EQUATIONS
-Summary of Design
-BARBENDING SCHEDULE
-Abstract of QUANTITY
-Abstracr of COST
-Detailed DRAWING


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Water Logging and Drainage and Ground Water Re-charge

Unit 12 ( Irrigation Engineering)

Water Logging and Drainage and Ground Water Re-charge

Definition of water logging:-

The natural process of making saturation of soil and unproductive due to excessive in its pore is known as the water logging.

 That area where it occurred is called water logging area.

Equation:-

 I = O+S

Where,

I= inflow of water

O = outflow of water

S= storage of water

Cause of water logging:-

Topographic condition: - when the surface of soil is not uniform, then the rain water collects and make small pound. So due to permeability of soil, this water increases the water table, hence water logging occurred.

Inadequate drainage:-

If the drainage facility is not adequate then, it will increase the chance of water logging by increasing the water table.

Canal seepage:-

Seepage of water from the earthen canal also raises the water table and hence water logging occurred.

Over irrigation:-

Irrigation water if used in excess over the field’s .then it will raises the water table and hence water logging occurred.

Rainfall and flood:-

Excess rainfall or flood will also cause the increasing in water table. By which water logging occurred.

Effects of water logging:-

Anchorage problems of plants and trees:-

If the soil becomes saturated then, the plant roots become very shallow and are easily uprooted when wind blows.

Growth of water loving wild plants:-

When the soil is water- logged water loving plant grow up which are harmful to the crop growth.

Increase in harmful salts:-

When the water table rise, then the upward moment of water brings harmful salts in the crop root zone. After evaporation, the water leaves behind salt, which reduce the production of crops.

Lowering of soil temperature:-

If moisture is present in the soil pores, the temperature of soil lowers down. Then bacteria activity retarded, which affects growth of crops badly.

Reduction of time for maturity:-

When the underwater is logged, then the crop period shortens which reduces the crop’s maturity time.

Detection of water logged area:-

1.      The water logged area can be easily detected by knowing the intensity of rainfall and the amount of runoff.  So to calculate the quantity of rain water which infiltrate into the sub soil and help in raising the level of water table.

2.      If the above information is no available then, a hole is made to be drilled to determine the level of underwater below the surface. If the water is available nearer to the root zone of the crops, then the area is called waterlogged area.

Preventive measures:-

1.      Controlling seepage from the canals: -

By following measures should be adopted to reduce seepage from the canals.

a)      By lowering the F.S.L of the canal:-

When the full supply level of canal is lowered then the loss of water’s seepage loss is reduced, and hence water logging is also reduced.

b)      By lining of canal :-

The bed and sides of the canal should be lined by protective materials so that seepage loss is reduced and hence water logging is also reduced.

Disposal of rain water:-

Rain water as soon as, it falls on the earth’s surface should be disposed of as soon as possible otherwise it will increase water logging.

Reducing the intensity of irrigation:-

The intensity should be reduced in this area where water logging occurred. Irrigation should be done rotation wise in different seasons.

REMEDIAL MEASURES:-

 The followings methods are adopted to reclaim the water logged areas.

 Installation of lift irrigation system:-

 When a tube well systems are introduce, then the level of underground water goes down and hence water logging is reduced.

Implementation of drainage scheme:-

Area is reclaimed by introducing overland and subsurface drainage schemes. Surface drainage may be of:-

1)      Providing seepage drain

2)      By providing storm water or surface drain.

3)      By providing lining of canal.

4)      Implementation of tube well in fields or water logging area.

Surface drain: -

Surface drains are that construction may be natural of artificial which remove surplus water from any area and placed over the surface of the soil. While aligning surface drains followings points which are given below, should be considered.

1)      Drain should follow lowest contour in a natural drainage line.

2)      The total alignment of drain should be straight, so that length of the drain is reduced and all this reduces the cost of construction of that drain. 

3)      The drain should not pass through any ponds and it also should not cross irrigation canals

Sub surface drains:-

When the depth of the surface drain increases, then the drain scheme becomes uneconomical. In this situation subsurface drain is used. Subsurface drain is pipe drain laid in permeable stratum below a ground water table. These drains are circular pipes made of vitrified clay. The trench is excavated in the ground up to the required depth and tile line is laid on 15 cm sand bed.

Ground water recharge:-

It is a process where water moves downward from surface water to ground water. This process usually below plant root. The water table recharge occurs naturally of artificially.

Natural Ground water is recharge by rain water, by melting of snow, by river and lake through permeability of soil

 Artificial ground water is recharge by making a pond, reservoirs and by storing rain watered.

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Tubewell Irrigation

Unit 6

Tube Well Irrigation

Occurrence of ground water:-During the rain or if water is collected on the surface of soil, then this water is goes downward till the hard strata is came. The moisture/water is then becomes static and collected in zones of soil which may be saturated or unsaturated zone .this water collected is then called occurrence of ground water in that zone.

Water table:-The upper most surface level of the zone of saturation is called a water table. When the rain water is collected in pound, then the water will goes downward due to seepage from unsaturated soil to saturated soil. This water is stopped by hard strata or rocks. So the seepage water is collected in saturated zone of soil layer. This water table is thus called underground water table.

Radius of influence:-  The radial distance from the centre of a wellbore hole to the point where there is no lowering of the water table is known as the radius of influence.

Depression head:- When the water is pumped out from the wall, then the level of the well is reduced, then the difference in levels between original water level in the well is called depression head.

Cone of depression:-A cone of depression are occurs in aquifers when ground water is pumped out from a well. In the unconfined aquifers the cone of depression is a reduction in pressure head surrounding the pumped well.

Aquifers:-It is a wet underground layer of water bearing permeable rocks (gravels, silts or sand).these are saturated regions of the subsurface that produce economical quantity of water to lift irrigation by tube well or well.

Unconfined aquifers:- Those aquifers which contains water table in their upper boundaries. This area contains almost all the ground water table. These aquifers cannot contain by any impervious layer.

Confined aquifers:- It is the aquifer which is confined by an impervious stratum at the top. That the water is contained between the hard strata around it just like as water is flowing through pipe.

Yield of well:- When the water is lifted from the well contineously. Then the  water level goes decreasing and there will be contribution of water from the surroundings layer into the well. If the lifting / water taken is increasing then the drawdown of water will be increasing and the fine silt /sand also entered into the well will started from the previous strata of the soil. At this stage water structure become unstable . due to this drawdown is always kept

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Irrigation Engineering

TOPICS COVERED
Intriduction to Irrigation
Types of Irrigation

UNIT-1      (IRRIGATION)  [CIVIL ENGINEERING]

INTRODUCTION

IRRIGATION:- The art, science and practice of supplying water artificially to land for producing crops is called Irrigation.

NECESSITY OF IRRIGATION:-

                                                        

1)      Non uniformity of rainfall:- 

                                                 Rainfall varies place to place as Punjab, Rajasthan, etc. rainfall is not same. Therefore in order to meet the water requirements of crop, it is very essential to provide facilities for irrigation.

2)      Crop requirement:-

                                    The requirement also depends upon the type of crop, its depends upon the time of sowing & the period of maturity.

3)      Economical use of water:-

                                               The crop production can be increased by supplying of proper quantity of water at proper time.

TYPES OF IRRIGATION:-

Artificial Irrigation:-
                             The process of supplying water artificially for the purpose of irrigation the field.

              The irrigation done by construction headwork sand canal is also referred as direct irrigation or river canal irrigation.

Types of Artificial Irrigation

1)      Lift Irrigation :-

                            The process of supplying water to the field for crop production by lifting it from its sources is called Lift Irrigation.

                                                             e.g. by wells, tube wells

2)      Flow Irrigation :-

                             The process of supplying water to the by flowing water by gravity is called flow Irrigation also called canal Irrigation.

3)      Sprinkler Irrigation :-

                                     The process of irrigation in which water is applied to the land through a system of pipe network connected to fine spray nozzles is called Sprinkler Irrigation.

METHODS OF IRRIGATION

1)      Free Flooding :-

                               In this method, water is supplied through ditches. It flows across the field. This method is mostly used in India, U.S.A., Egypt etc.                                               

2)       Border Flooding:-

                               In this farm id divided into no. of strips. The width & length of each strip should not exceed 9-18 m & 100 – 400 m respectively.

3)      Check Flooding :-

                                 In this case, farm is divided into small check areas. These are surrounded on all sides by low, flat ridges.

4)      Basin Flooding :-

                               It is same as check except that it is applied to orchard.

5)      Furrow Method :-

                             In this case crops are grown by supplying water b/w crops rows. This method consists in Appling water to the field by furrow supplying 8 – 24 cm per 100 m.

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