View Factor Orientation (or View factor or shape factor) plays an important role in radiation heat transfer. View factor is defined as, "fraction of radiation leaving surface 'i' and strike 'j' ". Summation Rule (View Factor) If there is are similar surfaces 'i' and 'j' , then: Blackbody Radiation Exchange Radiation Exchange between Opaque, Diffuse, Gray surfaces in an Enclosure 1. Opaque 2. Surfaces 3. Two surface enclosure Radiation Shield It is used to protect surfaces from radiation act like a reflective surface. References: Material from Class Lectures + Book named Fundamentals of Heat and Mass Transfer by Theodore L. Bergman + My knowledge. Photoshoped pics are developed. Some pics and GIF from Google. Videos from YouTube ( Engineering Sights ).
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Introduction to Statics
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Statics:
It is the branch of physics which deals with the analysis of load on physical systems which they are at rest.
Some topics related to Statics:
》 Space:
Space is a boundless, 3 dimensional extent in which objects and events occur and havery relative position and direction.
》 Time:
Time is a part of the measuring system used to sequence events, to compare the durations of events and the intervals between them, and to quantify rates of change such as the motions of object.
》 Mass:
It refers to the properties of matter which is equivalent to inertial mass, active gravitational mass and passive gravitational mass.
》 Force:
It is an influence which can change the state of rest or motion of an object.
》 Particle:
A particle is a small localized object having mass and volume.
》 Rigid Bodies:
Bodies which don't deform under load are called Rigid Bodies. It is the only supposition in Statics.
Types of Forces:
There are three types of forces, namely;
1. External Force.
2. Internal Force.
3. Constraint Force.
And, they are further divided as:
Causes of Force:
There are many causes of force which are as follows:
1. Constact Force
2. Friction
3. Gravitation
4. Electrostatics or magnetism, etc
Force Measuring Instruments:
Force can be measured by using :
1. Spring Balance
2. Load Cells ( high accuracy, measure weight with electric signals ), etc.
System of Forces:
There are three systems of forces, which are as follows:
1. Coplanar force system:
It is defined as;
Forces which are acting in same plane.
2. Collinear force system:
It is defined as;
Forces which are acting on the same line of action (axis).
3. Concurrent force system:
It is defined as;
Forces acting on the same point.
Principle of Transmissibility:
A force may be applied at any point in its given line of action without altering the resultant effects of the force external to the rigid body on which it acts.
TAPING CORRECTIONS There are two types of corrections depending upon the type of errors in tape due to the different conditions. 1. Systematic Errors : Slope Erroneous tape length Temperature Tension Sag 2. Random Errors : Slope Alignment Marking & Plumbing Temperature Tension & Sag 1. Temperature Correction It is necessary to apply this correction, since the length of a tape is increased as its temperature is raised, and consequently, the measured distance is too small. It is given by the formula, C t = 𝛼 (T m – T o )L Where, C t = the correction for temperature, in m. 𝛼 = the coefficient of thermal expansion. T m = the mean temperature during measurement. T o = the tempe...
Projection: The term Projection is defined as: Presentation of an image or an object on a surface. The principles used to graphically represent 3-D objects and structures on 2-D media and it based on two variables: Line of Sight. Plane of Projection. Line of Sight & Plane of Projection: Line of sight is divided into 2 types: Parallel Projection Converging Projection & A plane of projection is an imaginary flat plane upon which the image created by the lines of sight is projected. Orthographic Projection: When the projectors are parallel to each other and perpendicular to the plane of projection. The lines pf sight of the observer create a view on the screen. The screen is referred to as the Plane of Projection (POP). The lines of sight are called Projection lines or projectors. Rules of Orthographic Projection: Edges that are parallel to a plane of projection appear as lines. Edges that are incl...
Diffusion It is defined as, " The transportation of one atom from one state into other state " . Used for hardening of surfaces like die parts, gear, bolt, machine element. Hardening can be done using Temperature-Heat treatment ( diffusion couple ). There are two types of diffusion: Inter-diffusion ↔ in which atoms tend to migrate from region of high concentration to low concentration . Self-diffusion ↔ in which atoms migrate within a solid. Diffusion Mechanism There can be two conditions of moving atoms Empty spaces between adjacent sites. Atoms have sufficient energy to break bond with neighbors atoms which cause lattice distortion during displacement. If we rise temperature, small fractions of atoms is capable of diffusive motion (which cause lattice distortion). Types of Diffusion 1. Vacancy Diffusion It is defined as, " interchange of an atom from a normal lattice position to the adjacent vacant lattice site " . Extent of vacancy diffusion is a function...
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