Abstract:Crankshafts are among the most important parts in internal combustion engines, of which stirling engine is a useful example. Manufacturing process of a crankshaft, is considered as a three-step forging process using preform, due to the complexity in geometry. The most challenging step of the multistage forging process is to avoid stress concentration and to create uniformity of strain by controlling metal flow. In the present study, the final part was achieved under three manufacturing processes namely: upsett… Show more
“…A detailed analysis of scientific and technical information on Stirling engines (SE) from a number of foreign countries [1][2][3][4][5] showed that the most important elements in the development of this promising engine are the main heat exchangers of the internal circuit [6][7][8][9][10] and efficient heat supply in the external circuit [11,12].…”
This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).
“…A detailed analysis of scientific and technical information on Stirling engines (SE) from a number of foreign countries [1][2][3][4][5] showed that the most important elements in the development of this promising engine are the main heat exchangers of the internal circuit [6][7][8][9][10] and efficient heat supply in the external circuit [11,12].…”
This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).
“…time, energy and materials) while maintaining a high accuracy of optimization and/or screening results [28]. Among different techniques of DOE, the Taguchi method, and Response Surface Methodology (RSM) are of the most interest [29,30]. Developing a robust design in which the results are minimally affected by the external noises, is a vital element in DOE for any chemical composition.…”
In this study, the effect of nanosilica (SiO2) reinforcement on the gas separation properties of polyurethane/polyethylene glycol (PU-PEG) nanocomposite membrane was investigated. Formulation optimization of PU-PEG-SiO2 triple nanocomposite membrane was performed using experimental design and the Taguchi method. The effects of different formulation variables including nanosilica content, PEG content and molecular weight on the permeability and selectivity of CO2, N2, O2 and CH4 gases were investigated. The morphological and structural properties of the membranes were investigated by SEM, XRD, and FTIR analysis. Finally, the selectivity of optimal nanosilica-reinforced membrane was evaluated by Robeson's upper bound diagram. The obtained results showed that increasing the PEG content improves the gas permeability of the membrane due to its plasticizing effect. However, PEG plasticizing effect decreased at higher molecular weights and resulted in permeability reduction. By increasing the nanosilica content, the permeability of all the gasses reduced but the selectivity of the membrane for CO2 over CH4 and N2 improved. Finally, PU-20% PEG6000-5% SiO2 formulation which had the best selectivity for CO2/CH4 gases and was closer to Robeson's upper bound line was chosen as the optimal composition. In conclusion, PEG/nanosilica-reinforced Polyurethane nanocomposite membrane could serve as a promising candidate for efficient gas separation applications.
“…On the one hand, conducting numerical analysis requires statistical analysis [11][12][13][14][15] and experimental design, susceptible to errors and barriers such as uncertainty [16]. On the other hand, every experimental work needs a good calibration and inspection [17][18][19][20].…”
The X-ray diffractometer in the laboratory is a crucial instrument for analyzing materials in science. It can be used on almost any crystal material, and if the machine parameters are appropriately controlled, it can offer a lot of information about the sample’s characteristics. Nevertheless, the data obtained from these machines are complicated by an aberration function that can be resolved through calibration. In this study, a powder comprising of Barium Sulfate (BaSO4), Zinc Oxide (ZnO) and Aluminum (Al) was used as the first sample and a single crystal sample comprised of Gallium Nitride (GaN) and Aluminum Oxide (Al2O3). The required calibration parameters of the X-ray diffractometer namely: Straight Beam Alignment, Beam Cut Alignment and Sample Tilt Alignment for two samples were analyzed and carried out. Using the results of the X-ray spectrum, important parameters such as corresponding planes for peak positions, d-spacing of planes, intensities, smallest crystallite sizes and lattice parameters, and a comparison with the reference data were all carried out. As another result, the out-of-plane alignment and Full-Width- at Half-Maximum (FWHM) value for GaN could be determined using the rocking curve.
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