Temperature vs. heat

Fig. 15. Temperature vs heat generation or removal in estabHshing stationary states. The heavy line (—) shows the effect of reaction temperature on heat-generation rates for an exothermic first-order reaction. Curve A represents a high rate of heat removal resulting in the reactor operating at a low temperature with low conversion, ie, stationary state at a B represents a low rate of heat removal and consequently both a high temperature and high conversion at its stationary state, b and at intermediate heat removal rates, ie, C, multiple stationary states are attainable, c and The stationary state at c ...

Figure 5. Nitridation at different heating rates Figure 6. Peak temperature vs heating rate...

Temperature vs. heat flow rate in countercurrent flow. 

Caloric curve (temperature vs. heat) derived from peripheral collisions in reactions. 

DSC measurements of the energy during melting of aqueous polymer solutions and gels yield heats of mixing, and sorption [89] has been used to study the heat changes occurring in a polymer as it is cooled (plots of temperatures vs. heat flow (measured in mW)). 

Peak Temperature vs. Heat Generation Rates (Reactor Power)... 

The temperature difference may not remain constant throughout the flow path. Plots of temperature vs. pipe length for a system of two concentric pipes in which the annular fluid is cooled and the pipe fluid heated are shown in Figures 2-2 and 2-3. When the two fluids travel in opposite directions, as in Figure 2-2, they are in countercurrent flow. When the fluids travel in the same direction, as in Figure 2-3, they are in co-current flow. 

To evaluate the true temperature difference (driving force) in a mixed vapour condenser a condensation curve (temperature vs. enthalpy diagram) must be calculated showing the change in vapour temperature versus heat transferred throughout the condenser, Figure 12.48. The temperature profile will depend on the liquid-flow pattern in the condenser. There are two limiting conditions of condensate-vapour flow ... 

Figure 82. Variation of COP vs. heat pump supply temperature...

In principle two similar crucibles containing respectively a sample of the alloy under investigation and an inert reference specimen are cooled (or heated) together in a furnace. By means of conveniently inserted thermocouples it is possible to follow (1) the continuous reference temperature trend of the reference specimen, (2) the temperature trend of the specimen under examination and (3) the temperature difference (A 7 ) between the two. If, at a certain temperature, there is a change in the structure of the sample (that is, if a boundary line in the corresponding phase diagram is crossed), a variation in the slope of the temperature vs. time curve is recorded. As a consequence the A7 vs. time curve (or vs. temperature) shows a deviation from the baseline. The temperatures at which such deviations are observed are used to build the phase diagram. 

The points along a Rayleigh-Mikhel son Line are characterized by constancy of impulse function (P+mq)A as well as of mass velocity but not, in general, of temperature (Ref 2, p 101). Movement along such a line can represent flow without losses in a constant-area duct, with heat addition or removal and consequent changes rn temperature and hence in entropy. The Rayleigh-Mikhel son line is curved when plotted in the s,T (temperature vs entropy), the s,h (enthalpy vs entropy), and the dimensionless temperature vs density planes (Ref 2, p 173)... 

Figure 17. Maximum temperature vs. time for rods of circular and rectangular cross section with uniform heat generation, zero initial and surface temperature, and negligible axial heat conduction. Dotted curve gives value of r0 to use in dimensionless temperature and time scale for rectangular cross sections (3)...

Comparison of Release Data with Proposed Model. A summary of the cesium release data obtained with helium as carrier gas is shown in Figure 5, where the percentage of cesium remaining is plotted vs, heating time on semilogarithmic coordinates. In all of the experiments the flow rate was maintained at 300 cc./min. and the temperature at 730° = = 5°K. The geometric parameters are indicated on each curve. Since only about 5% of the sodium was vaporized in each experiment, the assumption of a stationary liquid-phase boundary is justified. 

Sect. 5.4), the heat transfer process can be modeled using classical unsteady state heat conduction theory [142-144]. From the mathematical solutions to heat conduction problems, a thermal diffusivity can be extracted from measurements of temperatures vs. time at a position inside a gel sample of well-defined geometry. 

G, Q) on Na-HiSil(650) and (0) on HiSil(700) vs. water coverage, v . The temperatures of heat treatments of these silicas are given in parentheses in degrees Celsius ( 5). 

Depending on the shape of temperature vs conversion trajectories, vitrification may take place at particular locations in the part. If this happens, the constitutive equations describing the kinetics must include the diffusional resistance that characterizes the sharp decrease in the polymerization rate when entering the vitrification region. In particular, vitrification can occur at the wall if Tw < TgltCl. In the examples that illustrate this section, it will be assumed that vitrification does not take place, but in the following section the influence of vitrification on the cure in a heated mold will be discussed. 

Important concepts in any analysis of the cure of thermosetting polymers are the possibility of reaching vitrification at particular locations in the part and the need to provide heat from an external source to devitrify the material and continue the cure. The analysis of vitrification cannot be avoided when the cure is performed at room temperature using different types of radiation (e.g., UV, EB, microwave) to initiate the polymerization. A temperature vs conversion transformation diagram (Chapter 5) may be useful in the design of cure cycles. 

Fig. 10. Electronic contribution to the heat capacity divided by temperature vs. log Q T for a series of La doped alloys of CeR Sb]. The data has been corrected for a phonon contribution, using heat capacity data from LaRr Sb] and a nuclear quadrupo-lar contribution from 121 Sb and 123 Sb (Takeda and Ishikawa, 2001).

---