Pressure Transmission in the Compaction Process for Nickel Powder using Finite Element Methods

The compression process is one of the more widely used industrial manufacturing methods for fabricating desired shape of specimens with various materials such as metals and ceramics. In the compaction process, the upper punch moves into the powder, and force is transmitted between particles, then achieving densification. In this process, the powder can be considered to be in a particulate state, which means that while the powder consists of solids, it has characteristics quite similar to the fluid. Therefore, particles in the process can be seen as responding to hydrostatic pressure, and it can be assumed that the pressure is constant. However, the forces acted on the inter-particle continue to change during the process. Many parameters affect the force change, including compaction speed and the contact angle between particles. However, it is very difficult to verify these effects through experiments because it is impossible to arrange the inter-particle angle. Therefore, in this study, the force transmission mechanism was simulated in the compaction process using FEM simulation. To examine the contact angle and force transmission between the particles, a green compact was modeled as individual particles rather than as a continuum green compact. Finally, it was confirmed through analysis that the pressure transmission between the particles remained constant during the compression process.11Ysciescopu

Ion-exchange membranes for blue energy generation: A short overview focused on nanocomposite

Blue energy can be harvested from salinity gradients between saline water and freshwater by reverse electrodialysis (RED). RED as a conversion technique to generate blue energy has received increasing attention in recent decades. As part of the RED system, ion exchange membranes (IEMs) are key elements to the success of future blue energy generation. However, its suboptimal performance often limits the applications and stagnates the deve­lopment of the technology. The key properties of IEMs include ion exchange capacity, perm­selectivity, and electrical resistance. The enhancement of such physical and electrochemical properties is crucial for studying energy production with acceptable output efficiency on a commercial scale. Recently, many studies have tried blending nanotechnology into the membrane fabrication process. Hybridizing inorganic nanomaterials with an organic polymeric material showed the great potential of improving electrical conductivity and perm­selectivity, as well as other membrane characteristics for power performance. In this short review, recent developments on the IEM synthesis in association with potential nanomaterials are reviewed and raising issues regarding the application and commercialization of RED-based energy production are discussed

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Department of Materials Science and EngineeringThe BIPV system has recently been actively studied as a new energy source with the development of solar cells. However, the third generation solar cells mainly used in BIPV systems are difficult to apply to full-scale BIPV systems due to problems such as selective solar light absorption, small active area, inherent color of organic materials, and low stability that are not yet commercialized have. In order to solve these problems, studies are being conducted to apply currently commercialized silicon solar cells to BIPV system. There is no problem in applying the silicon solar cell to the outer wall of the building, but there is a limitation in applying it to the glass window due to the weight problem of the silicon solar cell panel and the appearance of the unsuitable silicon solar cell. Therefore, the thickness reduction and transparency of the silicon should be studied. In this experiment, I reduced the thickness of the silicon wafer and drilled a fine hole in the solar cell to make a transparent silicon solar cell. Transparent silicon solar cells have not suffered a significant loss in efficiency compared to flat silicon solar cells, and the introduction of additional processes has the potential to increase the efficiency of transparent silicon solar cells beyond current levels.clos

DNA microarrays on nanoscale-controlled surface

We have developed new surface to ensure a proper spacing between immobilized biomolecules. While DNA microarray on this surface provided each probe DNA with ample space for hybridization with incoming target DNAs, the microarray showed enhanced discrimination efficiency for various types of single nucleotide polymorphism. The high discrimination efficiency holds for all tested cases (100:<1 for internal mismatched cases; 100:<28 for terminal mismatched ones). In addition, by investigating influence of hybridization temperature and washing condition on the fluorescence intensity and the discrimination efficiency with and without controlled mesospacing, it was observed that the nanoscale-controlled surface showed good discrimination efficiency in a wide range of temperature (37–50°C), and hybridization behavior on the surface was in agreement with the solution one. Intriguingly, it was found that washing process after the hybridization was critical for the high discrimination efficiency. For the particular case, washing process was so efficient that only 30 s washing was sufficient to reach the optimal discrimination ratio

Spinoffs versus non-spinoff entrepreneurs: Exploring post-bubble Japan’s entrepreneurial ecosystem

Purpose - The purpose of this study is to explore the role of spinoff entrepreneurs in the post-bubble Japan and ultimately to facilitate policy reforms that benefit entrepreneurs most in need of support. Design/methodology/approach - This study adopts a survey of Japanese entrepreneurs from 2003 to 2013. Exploiting the survey questions, the authors separate spinoff startups from the non-spinoff startups. Using this data set, this study first performs a logistic regression, followed by a chi-squared independence test between spinoff startups and firm performance. Findings - This study finds that while both human and social capital predict the probability of a firm’s positive performance, industry experience was the strongest predictor for the probability of performance. Originality/value - As Garvin (1983) stated, most research on spinoffs are limited to both industry type and location. The theoretical contribution of this study is to broaden the applicability of current entrepreneurship theories by considering industries beyond technological startups. The practical value of this study is to begin evaluating policies and their interaction effect with cultural context