Rheology and pipeline transportation of dense fly ash-water slurry

Usui, Hiromoto,Li, Lei,Suzuki, Hiroshi The Korean Society of Rheology 2001 Korea-Australia rheology journal Vol.13 No.1

Prediction of the maximum packing volume fraction with non-spherical particles has been one of the important problems in powder technology. The sphericity of fly ash particles depending on the particle diameter was measured by means of a CCD image processing instrument. An algorithm to predict the maximum packing volume fraction with non-spherical particles is proposed. The maximum packing volume fraction is used to predict the slurry viscosity under well dispersed conditions. For this purpose, Simha's cell model is applied for concentrated slurry with wide particle size distribution. Also, Usui's model developed for aggregative slurries is applied to predict the non-Newtonian viscosity of dense fly ash - water slurry. It is certified that the maximum packing volume fraction for non-spherical particles can be successfully used to predict slurry viscosity. The pressure drop in a pipe flow is predicted by using the non-Newtonian viscosity of dense fly ash-water slurry obtained by the present model. The predicted relationship between pressure drop and flow rate results in a good agreement with the experimented data obtained for a test rig with 50 mm inner diameter tube. Base on the design procedure proposed in this study, a feasibility study of fly ash hydraulic transportation system from a coal-fired power station to a controlled deposit site is carried out to give a future prospect of inexpensive fly ash transportation technology.

Rheological characteristics of non-spherical graphite suspensions

Mustafa, Hiromoto Usui,Ishizuki, Masanari,Shinge, Ibuki,Suzuki, Hiroshi The Korean Society of Rheology 2003 Korea-Australia rheology journal Vol.15 No.1

Since the microstructure of functional thin films depends on the dispersion characteristics of dense slurry, it is important to control the agglomerative nature of slurries under processing. The present authors have been discussing the model prediction of agglomerative nature and local rate of agglomeration in dense suspensions. The experiments have been peformed under shear flow using the nearly spherical and oblate type graphite particles. In this study, the experiment has been conducted using water and glycerol as dispersion media. Stress control type rheometer was used to measure the slurry rheology. Local agglomeration of graphite particles has been predicted by using Usui's model. The experimental results show that both the shape and slurry processing method affect on the local dispersion condition. The agglomeration formed by oblate type graphite particles seems to be more difficult to break up than that of spherical particles.

WOMEN, INSTITUTIONS, AND LEADERSHIP IN JAPAN

Usui, Chikako,Rose, Suzanna,Kageyama, Reiko 경남대학교 극동문제연구소 2003 ASIAN PERSPECTIVE Vol.27 No.3

This article presents an overview of women's representation in leadership Positions in major institutional spheres in Japan. It explores the literature on recent changes and institutional and psychological barriers to women's mobility. Although women have acted as agents of change who challenge the relationship between family and workplace, women's representation in leadership positions remains low. Their tight embeddedness in the institutions of family and community that is built upon the traditional gender division of labor inhibits their aspirations in pursuing non-family careers and has the effect of limiting women's access to channels of leadership. In response to changing family needs and growing international pressures, the governmen t has initiated policies for gender equality and women leadership. However, barriers to gender equality will persist unless certain organizational conditions and resources are promoted.

유전자 독성을 나타내지 않는 화학물질의 발암성 평가

Usui Toshimi DVM 한국실험동물학회 1992 한국실험동물학회 학술발표대회 논문집 Vol.1992 No.-

CB6F1-Tg rasH2 Mouse Carrying Human Prototype c-Ha-ras Gene As an Alternative Model For Carcinogenicity Testing For Pharmaceuticals

Usui, T.,Urano, K.,Suzuki, S.,Hioki, K.,Maruyama, Ch.,Tomisawa, M.,Ohnishi, Y.,Suemizu, H.,Yamamoto, S. Korean Society of ToxicologyKorea Environmental Mu 2001 Toxicological Research Vol.17 No.-

The international pharmaceutical and regulatory communities had been recognizing the limited utility of conventional rodent carcinogenicity study particularly on the second species, mouse, after intense investigation of carcinogenicity data base worldwide, and a new scheme for carcinogenicity testing for pharmaceuticals was proposed at the Expert Working Group on Safety in the International Conference on Harmonization (ICH) in 1996. CB6F 1-Tg rasH2 mouse carrying human prototype c-Ha-ras gene with its own promoter/enhancer is one oj the new carcinogenicity assay model for human cancer risk assessment. Studies have been conducted since 1992 to validate the transgenic (Tg) mice for rapid carcinogenicity test-ing, short term (26 weeks) studies with genotoxic (by Salmonella), non-genotoxic carcinogens, genotoxic non-carcinogens, non-genotoxic non-carcinogens revealed relatively high concordance oj the response of the Tg mouse with classical bioassay across classes of carcinogenic agents. Mechanistic basis for carcinogensis in the model are being elucidated in terms of the role of overexpression and/or point mutation of the transgene. This report review the initial studies of validation of the model and preliminary results of on-going ILSI HESI ACT project will be presented.

A PANORAMIC VIEW OF THE ASTEROIDS IN THE INNER SOLAR SYSTEM WITH AKARI

Usui, F.,Kuroda, D.,Muller, T.G.,Hasegawa, S.,Ishiguro, M.,Ootsubo, T.,Ueno, M.,AKARI SOSOS team, AKARI SOSOS team The Korean Astronomical Society 2012 天文學論叢 Vol.27 No.4

We constructed an unbiased asteroid catalog from the mid-infrared part of the All-Sky Survey with the Infrared Camera (IRC) on board AKARI. About 20% of the point source events recorded in the IRC All-Sky Survey observations were not used for the IRC Point Source Catalog in its production process because of a lack of multiple detection by position. Asteroids, which are moving objects on the celestial sphere, are included in these "residual events" We identified asteroids out of the residual events by matching them with the positions of known asteroids. For the identified asteroids, we calculated the size and albedo based on the Standard Thermal Model. Finally we had a new brand of asteroid catalog, which contains 5,120 objects, about twice as many as the IRAS asteroid catalog.

A comparative study of infrared asteroid surveys: IRAS, AKARI, and WISE

Usui, F.,Hasegawa, S.,Ishiguro, M.,Muller, T. G.,Ootsubo, T. Oxford University Press 2014 Publications of the Astronomical Society of Japan Vol.66 No.3

Two-stage Complete Deroofing Fistulotomy Approach for Horseshoe Fistula: Successful Surgery Leaving Continence Intact

Asami Usui,Gentaro Ishiyama,Akihiko Nishio,Maiko Kawamura,Yukiko Kono,Yuji Ishiyama 대한대장항문학회 2021 Annals of Coloproctolgy Vol.37 No.3

Purpose: Surgery of the horseshoe fistula is challenging due to its complex configuration and sphincter muscle involve- ment. Complete deroofing fistulotomy for horseshoe fistula is highly curative with the eradication of all fistulous lesions but has been discredited for its high incontinence rate. It was replaced with the more conservative Hanley’s procedure leaving the lateral tracts intact, despite its issue of recurrence. Our study aimed to report the outcomes of a procedure di- viding complete deroofing fistulotomy for horseshoe fistula into 2 stages to avoid impairment of sphincter function. Methods: We retrospectively reviewed 139 patients who underwent surgery for horseshoe fistula using the 2-stage com- plete deroofing fistulotomy method between 2014 and 2017. The first surgery deroofed the lateral tracts with an arch-like incision severing the anococcygeal ligament. The primary lesion was also drained and curetted. A seton was placed in the primary tract which was laid open in the second surgery after the lateral wound had partially healed. Results: Recurrence was observed in 12 patients. All were superficial recurrences except for 1, in which recurrence was confirmed in the primary lesion. Those with blind intersphincteric upward extensions had a significantly higher recurrence rate. Furthermore, patients who resided far from the hospital and could not make visits for frequent wound inspections also had a significantly higher recurrence rate. No patient had any continence issues at the end of the follow-up period. Conclusion: Managing horseshoe fistula with the 2-stage deroofing fistulotomy approach allows for eradication of the fis- tula tract without compromising anal sphincter function.

Silicon TFTs at the Dawn of FPD Technology

Setsuo Usui 한국물리학회 2009 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.54 No.1

This article reviews the research and development of crystalline Si films of early days (1980s∼) conducted in laboratories. Thin film transistors (TFTs) for large-area devices, such as contact-type image sensors and flat panel displays, were extensively investigated using ZMR (zone melting recrystallization) or Ar-ion laser annealing. In search of SOI (silicon on insulator) on glass substrates, the excimer laser annealing method was introduced to manufacture LTPS (low temperature poly-Si) TFTs on low-cost glass substrates and TFTs with good characteristics emerged as a result of using LTPS. This technology still has many problems and issues, but is pushed forward aiming at the realization of LTSS (low temperature single-crystalline silicon) films.

DATA REDUCTION OF AKARI/IRC SPECTROSCOPIC OBSERVATIONS

Fumihiko Usui,TAKASHI ONAKA 한국천문학회 2017 天文學論叢 Vol.32 No.1

AKARI performed about 10,000 spectroscopic observations with the Infrared Camera (IRC) during its mission phase. These IRC observations provide unique spectroscopic data at near- and mid-infrared wavelengthsfor studies of the next few decades because of its high sensitivity and unique wavelength coverage. In this paper, we present the current status of the activity for improving the IRC spectroscopicdata reduction process, including the toolkit and related data packages, and also discussthe goal of this project.