Answer:
Responsibility
Explanation:
By stamping the drawings that he was looking over, Jack Gillum conveys the fact that he is accepting responsibility for this work. The purpose of Gillum's stamp is to explain that such work has been under engineering review, and that it has fulfilled all the requirements that he watches our for. By putting his stamp in this work, Gillum accepts responsibility in case an error or a discrepancy is found in the drawings.
Answer:
See explaination
Explanation:
Rolling resistance which in some occassions can be called rolling friction or rolling drag, is the force resisting the motion when a body rolls on a surface.
In order to calculate our rolling resistance, there should be a force.
Please kindly check attachment for the step by step solution of the given problem.
Answer: I don't agree with the colleague. Because the lab technician may be conducting the shear strength experiment properly.
The difference between the shear strength of the sample in the lab and the field may be due to all or any of the following:
1) Sample size.
2) Sample shape.
3) Sample proportion.
4) Multiple test run on the same sample.
Explanation:
1) The sample size is very important in determining the shear strength of a sample, because the cohesion of a sample will vary with respect to the size of the sample, if the proportion remains the same. Therefore the sample size used in the lab and the field may not be equal.
2) The sample shape tells the arrangements of the particle lattice in the sample, which determines how cohesive a sample can be. Therefore if the shape of the samples are different, the stress properties won't be the same.
3) The cohesion of the sample will increase as the proportion of the sample increases. Therefore if the sample proportion are not the same, then the stress properties of the Mohr circle won't be the same.
4) If at all exactly the same sample used in the lab was the one used in the field, this will reduce the shear strength of the sample, because a repeative experiment on shear strength of a sample will reduce the cohesion of the sample. Therefore the cohesion of the sample during the lab experiment will be more than the cohesion of the sample during the field experiment.
Explanation:
Strengthening by grain size reduction
- It is based on the fact that dislocations will experience hindrances while trying to move from a grain into the next because of abrupt change in orientation of planes.
- Hindrances can be two types: forcible change of slip direction, and discontinuous slip plane.
- Smaller the grain size, often a dislocation encounters a hindrance. Yield strength of material will be increased.
- Yield strength is related to grain size (diameter, d ) as Hall Petch relation:
Strengthening by Grain size reduction (contd..)
- Grain size reduction improves not only strength, but also the toughness of many alloys.
- If d is average grain diameter, is grain boundary area per unit volume, is mean number of intercepts of grain boundaries per unit length of test line, is number of grains per unit area on a polished surface:
- Grain size can also be measured by comparing the grains at a fixed magnification with standard grain size charts.
- Other method: Use of ASTM grain size number (Z). It is related to grain diameter, (in mm) as follows:
Solid solution strengthening
- Impure foreign atoms in a single phase material produces lattice strains which can anchor the dislocations.
- Effectiveness of this strengthening depends on two factors size difference and volume fraction of solute. Solute atoms interact with dislocations in many ways:
- elastic interaction
- modulus interaction
- stacking-fault interaction
- electrical interaction
- short-range order interaction
- long-range order interaction