On the investigation of heat transfer in the presence of chemical conversions

The simplest boundary problem of unstationary heat-conduction equation, with the source depending on temperature as exp (—E*/T) is investigated in this paper.

The uniform convergence of successive approximations is proved for the corresponding integral equation; the solutions have been calculated in the first approximation at various limit cases. It has been also shown here that in the absence of “sexplosion” the temperature at each point will not exceed at any moment of time the corresponding stationary temperature.     

Mass transfer through laminar boundary layers—. Similar solutions of the b-Equation

As a preliminary to the presentation of general methods of mass transfer rate prediction, to follow in later papers, a study is made of the “similar” solutions of the differential equations governing the distribution of an arbitrary conserved property. The solutions available in the literature are collected. New solutions are presented valid for a two-parameter family of velocity distributions. It is shown that these suffice for the approximate prediction of the dimensionless conductance for a wide range of the variables: Prandtl/Schmidt number, Euler number, and driving force.     

The compression of rigid-perfectly-plastic material between rough parallel dies of unequal width

The results are given of calculations of the pressure to compress plastically, ideal material between perfectly rough parallel plates of variously unequal widths which do not overhang the material and in which the die width exceeds the material thickness. The rate of approach of the dies is also stated for certain die parameters. A particular solution is also given for the case when there is less than shearing friction between the material and the plates.     

Optical characteristics of silicon solar cells and of coatings for temperature control

Silicon photovoltaic cells, which are widely used in space vehicles for the direct conversion of solar radiation into electric power, exhibit an undesirable decrease in power output with increase in cell temperature. This article discusses the control of cell temperature in terms of the absorptance and the emittance of solar radiation by the cell surface. Using measured values of spectral reflectance to 25 microns, these parameters are determined for uncovered cells and for cells provided with glass filters and with silicon oxide films.     

Research on the stability of nearly zero flattened dispersion of photonic crystal fibers

To analyze the stability of nearly zero flattened dispersion, the dispersion deviations for three kinds of PCFs are calculated when the hole diameters deviate from their designed values. Numerical results show that around the wavelength of 1.55 μm, the dispersion deviations of both the PCF with three-fold symmetry core and the PCF with hexagonal lattice are much less than that of the PCF with different hole diameters in different rings. Therefore, the stabilities of nearly zero flattened dispersion of the first two kinds of PCFs are much better than that of the last one. Considering the confinement loss, the PCF with three-fold symmetry core is preferable to practical use.