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Fused deposition modeling (FDM) is the most versatile additive manufacturing technology owing to the low-cost materials that handle. However, FDM produce very rough parts which limit its use in molds and other industrial applications owing to staircase effect. To obtain smoother surfaces, a post-processing phase may be introduced. In this research, a non-contact finishing process to FDM parts using hot air was developed. The hot air is directed locally at the staircase in the surface till melting it which results after cooling to a smoother surface. An experimental setup was constructed to study the effects of different process parameters including air temperature, air flow rate and the moving velocity of air nozzle over parts surface. An improvement in the Roughness Average of a surfaces measured microscopic peaks and valleys (Ra) down to values of sub-micron was recorded from specimens with average surface roughness from7 to 8 μm.

In this paper we introduce the effect of initial stress on a magneto-thermoelastic functionally graded material (FGM) with Green Naghdi theory with energy dissipation. A system of PDE was obtained. The normal mode analysis method is used to convert these equations into ODE and get the analytical solution to write expressions for displacements, temperatures, stresses. Some comparisons carried out to view the initial stress influence on the field variables. Numerical results are graphed to view the influence of initial stress. Some particular cases are deduced in this study.

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A major component in PEM cell stack design and performance is the bipolar plates connecting the cells. Although many lightweight bipolar plates have been suggested yet cost and performance remain unresolved. Chemically treated Al was used. The Al substrate is pretreated in Zinc solution before dipping in different concentrations of nickel alloy solutions, mainly Ni-W-P, Ni-Co-P, and Ni-Co-W-P. A series of the coated samples was electroplated using Ni-P solution after electroless coating. The coated samples, where characterized and tested using, SEM, EDAX, Electrical Conductivity, and Electrochemical Corrosion techniques. The effect of changing alloy composition and deposition time on the electrical conductivity and corrosion resistance are reported. The most promising sample was that coated with Ni-Co-P before electroplating, this sample was machined for cross flow gas design and used as a bipolar plate in a PEM cell configuration. I-V performance test was conducted at room temperature and 23.7mA and 640mV with varying resistance. A duration test carried out for a period of 100 hours, showed constant voltage and current throughout the duration period of the test. The interrelations between properties, microstructure, composition, and performance are discussed.