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Drying reduces the moisture content of harvested crops thus slowing decay processes to enable longerterm storage. Solar dryers contain the crop being dried, to enhance solar energy collection incurring lower crop losses than are associated with open-sun drying and recurrent costs than are inherent to uses of fossil-fuels for drying. The influences of key environmental, operational and design parameters for solar dryers are discussed including: (i) psychrometry of drying processes and ambient conditions, (ii) how initial crop properties are converted to final desired product attributes, (iii) feasibility of using powered components such as fans and (iv) air-heating solar collector selection.

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By using a nonlinear model of surface morphological evolution, linear stability analysis, and self-consistent dynamical simulations, we analyze the effects of surface crystallographic orientation of a metallic thin film on its surface morphological response to the simultaneous action of an electric field and mechanical stress. The analysis reveals improved surface morphological stability over a range of misorientation angles between the electric-field direction and “easy surface diffusion” directions; for ⟨111⟩-oriented surfaces in fcc metals, the surface morphological response is superior to that of ⟨110⟩- and ⟨100⟩-oriented surfaces. This finding provides an interpretation for the longer electromigration lifetime of {111}-textured metallic interconnects.

We report a systematic investigation of complex asymptotic states reached in the electromigration-driven morphological evolution of void surfaces in thin films of face-centered cubic metals with ͗110͘-and ͗100͘-oriented film planes under the simultaneous action of biaxial tension. The analysis is based on selfconsistent dynamical simulations according to a realistic, well-validated, and fully nonlinear model. For ͗110͘-oriented film planes, we show that upon increasing the applied mechanical stress level, morphologically stable steady states transition to time-periodic states through a subcritical Hopf bifurcation. Further increase in the stress level triggers a sequence of period-doubling bifurcations that sets the driven nonlinear system on a route to chaos. For ͗100͘-oriented film planes, a transition from steady to time-periodic states also is found to occur at a critical stress level; in this case, the corresponding Hopf bifurcation is supercritical and the nonlinear system is not set on a route to chaos.