Strength-temperature, profiles

Fig. 105. Strength-temperature profiles of Araldite (Ciba-Geigy) epoxy adhesives on aluminium (Wake, 1982).

Fig. 106. Strength-temperature profile of an epoxy-phenolic adhesive on stainless steel (Hidux 1197A, Ciba-Geigy) (Wake, 1982).

Strength. Presumably, the stabilization is not quite accomplished under these conditions. A somewhat higher end temperature (profiles D and E, see Table 19) corrects for this defect, and carbon fibers with excellent tensile properties can be obtained with 30, 20 and 15 min stabilization time. An even shorter residence time (11 min) still results in interesting properties, though distinctly inferior to those of the 15-20 min samples. 

Thereafter total oxidation proceeds via gas phase radical chemistry. The conversion-temperature profile for a given substrate depends upon the activity of the catalyst and the inherent destructibility of the substrate. Here we propose that the lower the bond dissociation enthalpy of the weakest bond the more readily the substrate can be activated by the catalyst. At the basis of this hypothesis is the suggestion that active dtes in total oxidation catalysts distinguish between C-H bonds on a bond strength basis only. 

With respect to the W-type radiant tube used in the above noted comparative test, stress analysis was carried out in order to investigate the mechanical strength of the radiant tube. The method adopted is a Three Dimensional Elastic Stress Analysis using FEM ANSYS version 9, where the self-weight, measured temperature profile and assumed tube inside pressure at extraordinary combustion are considered. In the thermal stress analysis the measured tube surface temperature at 20 points, which seems to be timely, steady state was used as a smooth temperature curve over the measuring... 

Extruders the approach usually is to (i) adjust the temperature profile, (ii) check the hardware such as the thermocouples, controllers, speed, (iii) alter the processing conditions or (iv) change the resin or the screw and band design. The symptom-cause information is presented as issues related to production, off-spec thickness or shape, off-spec-strength, off-spec surface features, and usual symptoms. 

Despite the limitations of the Pennes bioheat equation, reasonable agreement between theory and experiment has been obtained for the measured temperature profiles in perfused tissue subject to various heating protocols. This equation is relatively easy to use, and it allows the manipulation of two blood-related parameters, the volumetric perfusion rate and the local arterial temperature, to modify the results. Pennes performed a series of experimental studies to validate his model. Over the years, the validity of the Pennes bioheat equation has been largely based on macroscopic thermal clearance measurements in which the adjustable free parameter in the theory, the blood perfusion rate [Xu and Anderson, 1999] was chosen to provide reasonable agreement with experiments for the temperature decay in the vicinity of the thermistor bead probe. Indeed, if the limitation of Pennes bioheat equation is an inaccurate estimation of the strength of the perfusion source term, an adjustable blood perfusion rate will overcome its limitations and provide reasonable agreement between experiment and theory. 

Previous studies (1-3) have shown that manganese redox chemistry in the oxygen evolving center (OEC) can be probed by flash-induced enhancements of the nmr relaxation rate of solvent protons (nmr-PRE). We report here an analysis of temperature profiles of the 1 and 2 flash nmr-PRE amplitudes at two field strengths, 0.48 and 1.08 Tesla. Results on model Mn complexes are also reported. 

It is of interest to predict the developed strength in the concrete liner that is unprotected and exposed to the freezing condition. This paper presents a technique to relate a concrete maturity curve to the temperature profile and age of the concrete in order to predict concrete liner strength development. By using this technique, a structural designer will have a more accurate value for the concrete liner to be used for optimized liner design. 

In order to obtain an accurate prediction of the temperature profile across the lining thickness and of the strength developed in the concrete, the following items need to be taken into consideration ... 

---