Why is the mechanical strength of the HAZ next to the fusion line of a non-heat treatable

       aluminum alloy much lower than that of the base metal?

Why does the mechanical strength of the HAZ of a non-heat treatable aluminum alloy

       increase with distance from the fusion line?

A vapor-compression refrigeration cycle operates at steady state with Refrigerant 134a as the working fluid. Saturated vapor enters the compressor at 2 bar, and saturated liquid exits the condenser at 10 bar. The isentropic compressor efficiency is 80%. The mass flow rate of refrigerant is 7 kg/min.


Determine:

(a) the compressor power, in kW.

(b) the refrigeration capacity, in tons.

(c) the coefficient of performance.

According to the valve adjustment diagram in gasoline engines, explain the following by stating on the figure. Intake valve opening, before 15° (top dead spot), Intake valve closing after 47° (bottom death spot), Exhaust valve opening before 41° (bottom death spot), Exhaust valve closing after 10° (top dead spot), Ignition advance before 15° (top dead spot)

Identify and discuss specific policy tools (taxes, carbon credits, tax credits, etc.) that would support building retrofitting.

a) What are the differences between S-beam and W-beam? Describe in no more than 250 words.

b) What are the applications of I beams and H beams? Write down two real-life applications for each.

c) What are the characteristics of the beam with a plane of symmetry in pure bending?

1) In your own words define “discretisation” and “degrees of freedom” in terms of the finite element method.

a) Give the governing equation for a thermal analysis and briefly explain each term. Using this equation, describe the three basic modes of heat transfer and how they are included into an FE analysis.

[Word limit: 200]

b) What do the terms sensitivity, verification, and validation mean in regards to the accuracy of a finite element analysis and how are they utilised?

1.  A type of section wherein the section view is probably located out of projection with the other regular or auxiliary views is a(n) ____ section.

a) removed

b) outline

c) revolved

d) aligned

2.  If there is a large area that needs to receive section lines, the ____ section allows for the section lines to only be applied around the perimeter.

a) area

b) conventional

c) special

d) outline

3. If an inclined surface is perpendicular to the frontal plane, how does it appear in the front view?

a) distorted shape

b) true size and shape

c) foreshortened shape

d) as an edge view (line)

4. The dihedral angle between two planes is shown true only in a view that features the ____ view of the edge of intersection between the two surfaces

a) front

b) point

c) side

d) normal

5. Which of the following statements concerning computer-generated auxiliary views is true?

a)Only full primary auxiliaries are possible

b)Auxiliary views are created as easily as principal views

c)Views will have extra tangency lines and projection lines

d)Auxiliary views must be adjacent to the front view

6. What geometric term applies to the path the ridge of a screw thread follows as it traverses the surface of a cylinder

a) spiral

b) ogee

c) helix

d) involute

7. Which of the following statements is the true rule of thumb drafters use when selecting the method of representing threads on a print

a) If the thread is drawn with a CAD system, then show a simplified representation

b) If the major diameter is more than 1 in real life, then show a schematic representation

c) If the major diameter is more than 1 in real life, then show a detailed representation

d) If the major diameter is more than 1 on the print, regardless of scale, then show a detailed representation

8. Which of the following Unified screw thread forms is a special series?

a) Fine

b) Coarse

c) Extra fine

d) Constant pitch

9. Which of the following classes of threads is fictitious?

a) Class 2B

b) Class 4B

c) Class 1A

d) Class 3

10. Which of the following statements concerning computer-generated screw thread representations is false?

a) Thread notes can be generated automatically

b) True projection is a common method of representing threads in orthographic views

c) Simplified representations are more common than schematic representations

d) Shaded images can be applied to the surface of a 3D model to give the appearance of screw threads

Derive the equation of motion for the mass-spring damper system of the seismic instrument as shown in the Figure. If the mass is 2 kg the spring stiffness 2.35 kN/m. damping coefficient 10 N.sm and 1-40 cm, determine (a) the undamped natural frequency (b) the undamped natural period o Rundup (a) (d) the damped natural froquency (e) the damped natural period

Question: The velocity components for a fluid flow are given as follow: z(x-2)2 u = ty w = xy (t is time) t+1 a.) Is the flow incompressible or not? b.) How many dimensions does the flow have? c.) Is the flow irrotational or rotational? d.) Find the local acceleration of the flow along x-direction at the points A(x,y,z,t)=A(0,1,1,4); B(x,y,z,t)=B{2,2,1,0)? e.) Find the convective acceleration of the flow along y-direction at the points A(x.y,z,t)=A(0,1,1,4); B(x,y,z,t)=B(2,2,1,0)?

Q1
a) With the aid of a sketch of the hydraulic system explain the following
i) A Reservoir ii) A pump and a prime mover iii) A pressure control and check valve iv) A power circuit which is made of actuators, motors or cylinders. v) Filter
b) List three functions that are performed by a reservoir and the purpose of baffles in it.
Q2
a) Define the term ‘Filtration’ in a hydraulic system.
b) Explain the difference between a depth and surface type filter and list three kinds of filters with different applications in a hydraulic system.
c) Name the three ratings used to classify hydraulic filters.
d) Explain what is meant by the terms;
i) Viscosity index
ii) Viscosity
iii) Demulsification
Q3
a) What is the procedure for isolating hydraulic machine before removing a component for servicing?
b) State a recommended procedure to use when you are testing a hydraulic line for leaks.
c) List two things you must take into consideration when you are using a cleaning solvent on hydraulic components.
d) State five contaminants that may be found in hydraulic systems.
Doc. No.: EXM/F/03 Page No.: 1/1 Issue No.: 1 Last Update: 15/04/08 Revision No.: 1 Date: 12/04/06 Author: EC Approved: DAA


Q4
a) Explain the term ‘Accumulator’ in a hydraulic system and its operation.
b) List the three different types of Accumulators used in a hydraulic system and explain the purpose of the nitrogen contained in it.
c) Draw the symbols of the following in a hydraulic circuit.
i) Accumulator
ii) Hydraulic pump
iii) Hydraulic motor
vi) Cylinder double acting
v) Ball check valve
Q5
a. State four different types of positive displacement pumps used in modern hydraulic systems and state the criteria on which a pump is selected for a system.
b. With a simple sketch describe the principle of operation of a gear pump.

If you leave in Northern Florida that the annual average temperature outside changes on the minimum to 40 F and Summer to 80 F, to save energy, is it better to turn off your water heater and turn it on 1 hour before shower or use, or let it to be on all the time. The water set temperature is normally around 110 F. Show with detail calculations if there is any energy saving.