1179 Slices
Medium 9788170088530

11_Chapter

Dr. B.C. Punmia ; Ashok Kr. Jain, Arun Kr. Jain Laxmi Publications PDF

11

PLANE TABLE

SURVEYING

CHAPTER

11.1

GENERAL: ACCESSORIES

Plane tabling is a graphical method of survey in which the field observations and plotting proceed simultaneously. It is means of making a manuscript map in the field while the ground can be seen by the topographer and without intermediate steps of recording and transcribing field notes. It can be used to tie topography by existing control and to carry its own control systems by triangulation or traverse and by lines of levels.

Instruments used

The following instuments are used in plane table survey:

1. The plane table with levelling head having arrangements for (a) levelling, (b) rotation about vertical axis, and (c) clamping in any required position.

2. Alidade for sighting

3. Plumbing fork and plumb bob.

4. Spirit level.

5. Compass.

6. Drawing paper with a rainproof cover.

1. The Plane Table (Fig. 11.1): Three distinct types of tables (board and tripod) having devices for levelling the plane table and controlling its orientation are in common use:

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Medium 9788131807385

Ch_7

Saradindu Panda Laxmi Publications PDF

168

Microelectronics and Optoelectronics Technology

Now,

The axial strain

\

= ea ea =

FG DL IJ

HL K

... (7.1)

0

Stress = s s=

F

=

Area

F

F DI pG J

H 2K

2

... (7.2)

Strain is a dimensionless quantity, and is usually expressed in units of 10–6 or microstrains, because for most materials strain values are quite small.

The units of stress s are commonly N/m2 or Pa.

The standard sign convention for stress is for tensile stresses to be negative and compressive stresses to be negative and compressive stresses to be positive.

Here the force F, in figure is acting perpendicularly to the end of the rod. This type of force is termed an axial force, and results in an axial strain ea and axial stress ¶a.

Shear forces, which act parallel to the surface of a body, generate shear stress and strain. From the Hooke’s law we get, where

¶ = eE

E = slope of the stress-strain curve.

... (7.3)

Another important mechanical effect is the change in lateral dimensions due to an axial force.

The rod in Fig. 1 is shown as decreasing in diameter as a result of the axial tensile force F. This change in width is characterised by a lateral strain ec, which is related to the axial strain ea by Poisson’s ratio v by, v =–

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Medium 9788131805220

ALLC5-3

Manish Goyal Laxmi Publications PDF

353

NUMERICAL INTEGRATION AND DIFFERENTIATION

Example 3. Evaluate

z

6

dx

0

1 + x2

by using

(i) Simpson’s one-third rule

(ii) Simpson’s three-eighth rule

(iii) Trapezoidal rule

(iv) Weddle’s rule.

Sol. Divide the interval (0, 6) into six parts each of width h = 1.

The values of f(x) =

1

1 + x2

are given below :

x :

0

1

2

3

f(x) :

1

0.5

0.2

0.1

y0

y1

y2

y3

4

5

6

1

17 y4

1

26 y5

1

37 y6

(i) By Simpson’s one-third rule,

z

dx

6

1+ x

0

2

=

h

[(y0 + y6) + 4(y1 + y3 + y5) + 2(y2 + y4)]

3

=

1

3

LMFG 1 + 1 IJ + 4 FG0.5 + 0.1 + 1 IJ + 2 FG0.2 + 1 IJ OP = 1.366173413.

H 17 K Q

26 K

NH 37 K H

(ii) By Simpson’s three-eighth rule,

z

6

0

dx

1+ x

2

=

3h

[(y0 + y6) + 3(y1 + y2 + y4 + y5) + 2y3]

8

=

3

8

LMFG 1 + 1 IJ + 3 FG.5 + .2 + 1 + 1 IJ + 2(.1)OP = 1.357080836.

17 26 K

NH 37 K H

Q

(iii) By Trapezoidal rule,

z

6

0

dx

1+ x

2

=

h

[(y0 + y6) + 2(y1 + y2 + y3 + y4 + y5)]

2

=

1

2

(iv) By Weddle’s rule,

z

6

0

dx

1+ x

2

LMFG 1 + 1 IJ + 2 FG.5 + .2 + .1 + 1 + 1 IJ OP = 1.410798581.

17 26 K Q

NH 37 K H

=

3h

[y + 5y1 + y2 + 6y3 + y4 + 5y5 + y6]

10 0

=

1

3

1

1

+

1 + 5(.5) + .2 + 6(.1) +

+5

= 1.373447475.

17

10

26

37

LM

N

FG IJ

H K

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Medium 9788131803660

Ch_2f

Dipak Chandra Ghosh, Nripesh Chandra Ghosh, and Prabir Kumar Haldar Laxmi Publications PDF

��

Jean Louis Marie

Poiseuille

2C

Chapter

Viscosity

2C.1

INTRODUCTION

Liquids and gases together are termed as fluids as there are some analogus in behaviour between them. Fluid cannot permanent by withstand any shearing stress. However, gases are compressible but liquids are not the same way. When a liquid is at rest, do not show any kind of rigidity. But when ever a liquid flows, there is a relative motion between the adjacent layers of the liquid, internal tangential forces act between two adjacent layers opposing this relative motion arise.

If we consider any particular layer of the liquid we find that the layer immediately above it is moving faster than the layer immediately below it.

The property of a liquid owing to which it opposes the relative motion between its different layers is called viscosity.

Their magnitude differing from one liquid to another.

2C.2

v + 3dv v + 2dv v + dv v v – dv v – 2dv

Figure 2C.1

FLOW OF LIQUIDS

The liquids flow by two different ways:

(a) Streamlined flow

When a liquid flows such that each particle passing a certain point follows exactly the same path as the preceding particles which passed the same point, the flow is said to be streamlined and the path is called a streamline. v2

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Medium 9789381159064

Ch_7_F

Arijit Saha; Nilotpal Manna Laxmi Publications PDF

7

O PTOELEC TRONIC

DISPLAY DEVICES

7.1

INTRODUCTION

Visual display is one of the basic requirements of the recent systems. As the technology advances and most of the systems are based on the electronic devices, development of display systems is not lagging behind. Depending on the applications, various display devices have been developed to meet the requirements. Display devices can be divided into two broad categories: (a) those that emit radiation their own (active devices) and (b) those that in some way modulate incident radiation to provide display information (passive devices). However all the display devices are characterized by the general term as Luminescence, which is used to describe the emission of radiation from a solid when it is supplied with some form of energy. The type of luminescence may be distinguished by its method of excitation, as described below:

· Photoluminescence: Excitation arises from the absorption of photons.

· Cathodoluminescence: Excitation by the bombardment with a beam of electrons.

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