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Fixation of Carbon Dioxide via Direct Mineral Carbonation Using Concrete Sludge
Get PDFConcrete sludge is a waste fresh concrete returned from construction sites. Due to its high alkalinity, the waste treatment of concrete sludge is costly and power consuming process; neutralization by using acids is necessary before disposal as solid waste. We have developed a new type of fixation process of carbon dioxide using concrete sludge. By a simple bubbling of carbon dioxide gas into model concrete sludge, a mixture of cement and water, resulted in the formation of calcium carbonate, where calcium concentration and pH decreased with time. The effects of operation conditions including cement/water ratio, bubbling time, CO_2 flow rate, CO_2 partial pressure on the CO_2 fixation performance were examined. The highest fixation ratio was 0.085 mmol/(min∙g-cement), and the highest degree of CO_2 fixation was 91.5%.departmental bulletin pape
A Quantitative Investigation into Student Outcomes from Learning Assistant Engagement in Economics Class Hours
Get PDFThis paper employs an econometric method in estimating student outcomes from learning assistant (LA) engagement in economics class hours. Many US universities have already introduced an LA system into undergraduate courses, primarily in science, technology, engineering, and mathematics (STEM) disciplines. The author and his colleagues applied the LA model to an economics course at a Japanese university. We expected that LAs would also help economics students learn more readily and energize their in-class learning. Thus this paper investigates the effect of learning assistant support on the students in an introductory macroeconomics course. While circumventing collinearity problems between explanatory variables, the ordinary least squares estimation reveals that the LA model in economics fosters students’ exam performance. Hence this paper provides one piece of evidence supporting the use of LAs not only in STEM education but also in economics.departmental bulletin pape
The Effects of Human Resource Management Practices and Motivation on Individual Knowledge Sharing Behavior : An Empirical Study for R&D Professionals in Japanese Multinational Enterprises
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Optimal time of tert-Butyl hydroperoxide to induce ferroptosis in cancerous cell lines
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Image Encryption and Encoding based on Optical Systems
Get PDFOptical encryption and encoding techniques are attractive to researchers, because they can optically encrypt an image at high speed. Especially, double random phase encoding (DRPE) is known as a typical optical encryption and encoding method. DRPE encrypts images by random phase modulations in the spatial and Fourier plane. Many researchers have reported the security analysis of DRPE. It is important to investigate the security strength against some attacks, such as known-plaintext attack (KPA). In this paper, we introduce the known-plaintext attack-based analysis of DRPE. DRPE is easy to expand because the optical system of DRPE is simple. Therefore, there are various types of DRPE, such as DRPE based on fractional Fourier transform and Fresnel transform. However, the optical systems are based on coherent light. Therefore, we introduce the proposed incoherent optical system of DRPE. In the future, we expect new applications based on DRPE algorithm for a camera and sensor.departmental bulletin pape
School Experience of Zainichi Korean and Attitudes toward Hate Speech : The Collective Identity against Racism Formed in Joseon-School
Get PDFHate speech, a new type of racism against Zainichi Korean, has become a social issue in Japan since the 2000s. The purpose of this paper is to explain attitudes that Zainichi Koreans forms toward this new racism in association with their life courses and identities. The qualitative survey, which combines life course interview and reaction survey conducted with the hate speech card, revealed that the attitudes toward hate speech can be divided into passive and assertive and those who have attended Korean ethnic school (Joseon-School) tend to actively “object to” the racist. I argue that this anti-racist disposition is formed through participating in "the special class" and the social movements held in the school. The findings obtained in this article contribute not only to migration and ethnic studies but also to the anti-racism movement in Japan.departmental bulletin pape