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Applying mechanical pressure on a solid boundary contact using a thin porous layer has been found to reduce the pore size and porosity near the wall region, limiting the flow and mass transport properties. This reduction may affect the overall performance of devices such as the electroosmotic pump that generally uses a porous media with constant porosity in an electric field. Therefore, to improve the performance of such devices, a composite porous layer that uses a combination of different porosity value based on the location in the porous domain, is employed with a higher porosity near the wall region than that in the central region. In this study, a numerical simulation is conducted to investigate the fluid dynamic and mass transport characteristics using a composite porous layer with electroosmotic flow. A comparison of the results with the pressure-driven flow shows the effectiveness of the composite porous layer in compensating for the loss of porosity and in improving device performance. The proposed methodology may also enhance the performance of green energy devices such as fuel cells.

The manufacture of helical pinion gears has involved machining processes such as hobbing and shaving to achieve the required dimensional accuracy. However, these conventional processes have some disadvantages such as excessive material loss, low productivity, high-energy consumption, and high carbon emissions. To overcome these problems, a cold extrusion process is applied to the manufacture of helical gears. In this study, we analyze the environmental effects of the cold extrusion process, designed for the sustainable production of helical gears. We quantitatively analyze the environmental effects of the conventional machining and cold extrusion processes, using the Life Cycle Assessment technique in accordance with ISO 14000. This analysis includes the energy consumption and carbon emissions for a helical gear manufactured using the conventional machining processes and those of single- and double-type gears manufactured using the cold extrusion process. Moreover, the material properties of the extruded helical gears are compared with the conventionally machined gears. In conclusion, the extruded gears exhibited a higher strength while consuming less energy during their manufacture than the gears manufactured using the conventional machining processes. Further, this alternative process is more cost effective as it generates less waste and exhibits high productivity compared to the conventional machining processes.

The original version of this article unfortunately contains a mistake. The acknowledgement section of the above article is incorrect. The correct acknowledgements are as follows