(a) Determine the principal stresses. (b) Determine the unit vectors defining the principal directions. (c) Determine whether yielding is predicted according to the Tresca criterion. (d) Determine whether yielding is predicted according to the von Mises criterion.

For materials with a specific heat capacity of less than 700 J/kg.C, plot agraph of refractive index against density. If you wanted a high value of density and a low value of refractive index,which would be the best material?

(a) Sketch the (220) plane; (b) Sketch the (321) direction; (c) Determine the distance between the nearest parallel (111) planes.

A two-stage ammonia food-freezing plant with a desired capacity of 528,000 kJ/h at -40°C evaporating temperature and 35°C condensing temperature has a flash intercooling system with a liquid sub cooler. The vapour leaving the evaporator is at -30°C and entering the first-stage compressor is at -15°C. The vapour leaving the flash chamber is superheated by 10°C in the suction line to the second-stage compressor. Water intercooling is done to cool the vapour to 45°C. Adiabatic efficiencies of both compressors are 0.75. The volumetric efficiencies of first- and second-stage compressors are 0.65 and 0.77 respectively. a) Sketch a fully labelled schematic diagram of the system identifying all the state points and then illustrate the cycle on a (p-h) chart. b) Find the piston displacements, discharge temperatures and power requirements of the two compressors

In practical machining process, the chip formation shows shear zone rather than shear plane, and a secondary shear zone resulting from tool-chip friction.

Q1. Calculate the activation energy for vacancy formation in aluminum, given that the23-3equilibrium number of vacancies at 500°C (773 K) is 7.57 × 10 m .The atomic weight and3density (at 500°C) for aluminum are, respectively, 26.98 g/mol and 2.62 g/cm . (7 marks)

Q#2. A metal wire of 50 cm length and 1 mm radius's exposed to a sequence of loading and unloading steps as described below. The stress-strain data for the metal is given in Figure 1. (5 points) Step 1: wire is loaded with a force of 628 N Step 2: the load in Step 1 is tripled (3 times) Step 3: the wire is unloaded a) What is the total length of the wire in Step 1. b) What is the total length in Step 2? c) What is the total length in Step 3? d) What is the final yield strength?

1A) Based on the accompanying electronegativity data, calculate the percent ionic character in indium phosphide (InP), and determine whether the bonding in InP is ionic, covalent, metallic, hydrogen, or van der Waals.

It is generally agreed among researchers that the primary driving force for sintering is the reduction of surface energy.

A covalent bond is one where a. Electrons are shared between atoms b. Electrons are transferred between atoms C. Intermolecular forces are formed between molecules d. None of these