Describe both factors that influence the durability of asphalt materials and the effect each factor has on the materials.
What will be an ideal response?
The durability of an asphaltic material is dependent on its ability to resist
weathering. Some of the factors that influence weathering are oxidation,
volatilization, temperature, exposed surface area, and age hardening.
Oxidation is a chemical reaction that causes gradual and permanent hardening and
eventually considerable loss of the plastic characteristics of the asphalt material.
Volatilization is the evaporation of the lighter hydrocarbons from the asphaltic
materials which causes loss of the plastic characteristics of the material.
As temperatures increase, so do the rates of oxidation and volatilization.
The rate of hardening is directly proportional to the ratio of the surface area to the
volume.
Age hardening occurs when an asphaltic material is heated and allowed to cool.
A gel-like structure is formed that hardens over time, significantly within the first
few hours after cooling and decreasing to an almost negligible amount in a year.
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The maximum lateral tire runout is:
A. 0.015 inch B. 0.035 inch C. 0.075 inch D. 0.100 inch
Describe a chick embryo at the end of each week of incubation.
What will be an ideal response?
Devices using single-ended interfaces have better noise immunity than those using differential signaling
Indicate whether the statement is true or false
A separately excited DC motor has the following parameters:
Ra = 0.1 ? R f = 100 ? La = 0.2 H L f = 0.02 H Ka = 0.8 K f = 0.9 An inertial load has J = 0.5 kg-m2 and b = 2 N-m-s/rad. No external load torque is applied. a. Sketch a diagram of the system and derive the (three) differential equations. b. Sketch a simulation block diagram of the system (you should have three integrators). c. Code the diagram, using Simulink. d. Run the following simulations: Armature control. Assume a constant field with Vf = 100 V; now simulate the response of the system when the armature voltage changes in step fashion from 50 to 75 V. Save and plot the current and angular speed responses. Field control. Assume a constant armature voltage with Va = 100 V; now simulate the response of the system when the field voltage changes in step fashion from 75 to 50 V. This procedure is called field weakening. Save and plot the current and angular speed responses.