A train is moving in the forward direction at 0.65c. The tracks are 1.5m apart and the light is at the center point between the tracks. An observer is 3m from the train when the beam is no longer visible (observer not in the beam). What half angular spread of the headlight beam does the train’s engineer see? Express in degrees.
In: Mechanical Engineering
What is the condition for self-locking block brake?
In: Mechanical Engineering
Air enters a food dehydration system at condition 1 and exits at condition 2. What is the change in enthalpy (kJ/kg dry air) of the air as it passes through the system: Condition 1: Tdb = 30C; Twb = 15C. Condition 2: Tdb = 100C; Twb = 40C. Select the closest answer.
In: Mechanical Engineering
Which statement correctly describes mirror symmetry boundary conditions in thermal analysis?
A. Symmetry boundary conditions require definition of convection coefficient on the faces in the plane of symmetry
B. Symmetry boundary conditions can’t be used if conduction is modeled
C. Symmetry boundary conditions do not apply to thermal analysis
D. No thermal condition must be defined on faces in the plane of symmetry
In: Mechanical Engineering
What are mechanical property parameters and what are physical property parameters? What are their differences?
In: Mechanical Engineering
The figure 3 represents the construction hoist used to handle material handling in construction sites Figure 3: Construction Hoist
a) Explain the working principle of construction hoist and its application.
b) Identify the mechanism used for construction hoist.
c) Identify the driving link and generate the kinematic diagram.
d) How the vibration on the machine is managed during operation?
In: Mechanical Engineering
Use the graph below to sketch curves that demonstrate anticipated stress-strain behavior for two materials. One curve should represent a typical metal, the other a typical ceramic. Label the curves and use them to describe anticipated differences in material properties.
In: Mechanical Engineering
1. Point defects- such as vacancies and interstitials
– are examples of crystalline defects. Why are
they called “crystalline”? Are there no vacancies and interstitials
in non- crystalline solids? Justify
your answer.
2. How do grain boundaries influence the chemical; and
mechanical properties of a metal?
(must mention about the corrosion properties)
3. How would you expect the diffusion process to
change if the slide was changed from amorphous
to crystalline glass?
In: Mechanical Engineering
1.Why plastic beams are not used to construct buildings and bridges?List THREE properties that make
plastics unsuitable for this application?
2.How a temperature drop of 50 C below 0 C would affect polythene bottle? Explain.
3.What type of bonding explains function of adhesives?
4.Can ceramic materials be used as material for the beams? If not, explain why? List properties that make
them unsuitable for this application?
In: Mechanical Engineering
Aluminium alloys are commonly used in aviation industry. Discuss the applicability of aluminium alloys to be used in wings of a typical passenger airplane considering the aspects given below:
(a) Performance (altering loads, thermal, chemical, corrosive, etc. effects)
(b) Properties (mechanical, corrosive, erosive and thermal properties)
(c) Structure (crystal structure, microstructure, alloying)
(d) Processing
In: Mechanical Engineering
Give an example for each physical, mechanical, electrical and thermal properties of material, identify practical application if it were to be used in an engineering context.
In: Mechanical Engineering
One aspect of material science and engineering is the investigation of relationships that exist between the structures and properties of materials. By structure, we mean how some internal component(s) of the material is arranged.
Ceramics possess certain unique properties that are not present
in other types of materials due to its microstructure. Critically
evaluate and express your opinion on what you think are the
desirable characteristics of ceramics compared to other types of
materials. Justify your arguments by giving examples of the
applications of ceramics.
In: Mechanical Engineering
subject name Materials and processes in manufacturing
1) The properties of a material are related to the __________ of the material
2) How do we describe the structure of a material?
3) Are the properties of a material always the same in all directions? What term is used to describe this ?
4) What is the term used to describe the possibility of some elements (like carbon) to form different structures where the only difference is the arrangement of the atoms?
5) Stress can occur is several modes. List 2: _____, _____
6) Polymer materials have a molecular structure, rather than the lattice structure found in most metals. What kinds of bonds between atoms are found in most polymer materials ?
7) Polymers are formed in nature ( woods, leather, shellac, silk, ) and are engineered. Examples? ________________________
In: Mechanical Engineering
1. Explain how an understanding of the 4 classes of materials and their general properties aid in the initial selection or elimination of materials suitable for a specific application. I.E. First outline some of the main general properties of each class, DO NOT GIVE EXAMPLES OF COMPONENTS AFTER EACH CLASS SECTION! Then describe how you would apply that knowledge to choose a suitable material for ONE specific component. ONLY ONE COMPONENT SHOULD BE PRESENTED AFTER YOU HAVE OUTLINED THE GENERAL PROPERTIES. I.E, SAY WHY ONE CLASS COULD NOT BE USED AND WHY ANOTHER CLASS CAN BE USED.
In: Mechanical Engineering
What is the Atomic/chemical bonding of the following materials:
1- Uranium (alpha phase)
2- Bombyx Mori Silk
3- Calicium Aluminate Cement - 1 (CAC-1)
And how this affects their properties ?
In: Mechanical Engineering