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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Ceramics
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Ceramics
It is defined as, "when two metal react with each other to form a compound not solid solution".
Inorganic material (between metallic & non-metallic materials)
Firing or Burnt Stuff ⇉ Desired properties of ceramics are achieved at very high temperature heat treatment process.
Ceramic structure ⇉ more complex structure than metals and has at least 2 elements.
Characteristics of Ceramic Structure
Exhibit combinations of ionic and covalent bond.
Degree of ionic character depend on electronegativity.
Influence on Ceramic Structure
Magnitude of charge on each component (crystal should be neutral).
Relative sizes of cation and anions (cation radii < anion radii i.e. rC/rA < 1).
Coordination Configuration
It is defined as, "Maximum number of neighboring touching center atoms".
Stable Ceramic structure ⇉ form when anions surrounding a cation are in contact.
For a specific coordination number ⇉ critical or min. rC/rA has a constant value.
Computation of Cation-Anion Ratio
Consider Hard-Sphere model.
Size of an ion depend upon coordination number.
Charge on ion will influence its radius.
Types of Ceramic Structure
1. AX Type Crystal Structure
It is defined as, "materials in which there are equal number of cations and anions". Eg: NaCl (FCC), CsCl (BCC).
2. AmXp Type Ceramic Structure
It is defined as, "materials having different number of cations and anions (different charges on atoms)". Eg: CaF2 (FCC).
Defects in Ceramic Structure
Frankel Defect ⇉ Defect involve cation-vacancy or cation-interstitial pair.
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...
Solid Mechanics OR Mechanics of Materials OR Strength of Materials: It is the study of mechanics of body i.e. forces and their effects on deformable solids under different loading conditions. Deformable Body Mechanics: It is the study of non-rigid solid structures which deform under load. Deformation/Distortion ⇾ change of shape and size OR have some relative displacement or rotation of particles. It happens when we apply combined load. Rigid Body Motion ⇾ Translation or rotation of particles but having constant distance between particles. Since deformation occur at particular load. Below this load, every body is considered as rigid body . Types of Load: Point Load ⇾ Load apply on a single point i.e. concentrated load. Uniformly Distributed Load (UDL) ⇾ Load remains uniform throughout an area of element like beam. Varying Distributed Load (VDL) ⇾ Load varies with length with constant rate. Moment ⇾ It measures the tend...
Strain Transformation Principal Strain and stresses can occur in the same directions. Material Properties Relation (Young, bulk Rigidity Modulus) ⇼ Hooke's Law General State of Strain ⇼ Є X , Є Y , Є Z and ૪ X , ૪ Y , ૪ Z . Stress (normal or shear)/ Strain (normal or shear) ⇼ vary with element orientation. Transformation equations for Plane strain derived from: Interpretation of Experimental measurements Represent in graphical form for plane strain (Mohr's Circle). Geometry and independent of material properties. Mohr's Circle It is defined as., " A graphical method for determining normal and shear Shear stresses without using the stress transformation equations " . While considering the circle CCW ⇼ Shear strain positive upward & Normal strain positive towards right. The construction of Mohr's circle (with normal and shear stresses are known) is quite easy which include following steps: Draw a set o...
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