Cooling deflection temperature

Most of the deflection shown for the 0.010-inch thick sample can be attributed to either electrical drift in the instrumentation or a slight cooling water temperature change. A detectable change in deflection reading does not occur until after the first minute of irradiation, and the drift is approximately linear with time. Such drift in this low deflection range (1 to 2 X 10"5 inches) was not uncommon. 

The best molds are made of aluminum with water-cooling channels cut into them. Tooling costs are low, and heat transfer is high. The formed plastic sheet must be held against the mold surface until it is cooled to the solid state. This is often judged by the heat deflection temperature at 455 kPa (66 psi). 

After the thickness of the sample was measured, each sample was heated to 200°C and held at that temperature for ten minutes. Next, the deflection of the beam was measured at ten degree Intervals as the sample was cooled to -30°C at l°C/min. The sample was also held at -30°C for ten minutes. The deflection was again measured at ten degree intervals as the sample was heated to 200°C at l°C/min. 

To determine the effect of humidity on the stress, one sample (0% excess MDA) was placed in the oven with desiccant at 200°C for 6 hours, and the deflection was measured during that time span. The sample was next cooled to room temperature, weighed, and returned to the oven at 200°C the dish of desiccant was now replaced by a dish of water. The deflection as a function of time was again measured over a time span of 6 hours. The sample was cooled to room temperature and weighed again to determine percent weight gain. 

In interpreting cooling ages across a landscape, the most relevant isotherm is that of the thermochronometer s closure temperature. Figure 2 shows that the 60 °C isotherm, a typical Tc for the apatite (U-Th)/He system in a slowly eroding landscape, will be deflected to about 45%... 

Frequently, both kinds of adiabats must be employed to follow the behavior of a parcel of air. A parcel of dry air may rise by its own buoyancy, or may be pushed up by orographic lifting, which occurs when winds meet mountains and are deflected upward. The temperature of the air parcel follows the dry adiabat until water vapor condensation is incipient with further cooling, condensation can occur. If it is assumed that supercooling (a nonequilibrium situation in which air cools below the dew point without condensation) does not occur, the parcel of air then moves upward following the corresponding wet adiabat. Conditional stability refers to conditions under which dry,... 

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