• Title/Summary/Keyword: Pressure Medium

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Performance Evaluation and Improvement of Medium and Small Scale Rice Polishers(II) - medium scale rice polisher - (중.소형 연미기의 성능평가 및 성능개선에 관한 연구(II) - 중형 연미기에 대하여 -)

  • 정종훈;권홍관
    • Journal of Biosystems Engineering
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    • v.23 no.5
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    • pp.445-456
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    • 1998
  • This study was carried out to evaluate the performance of a medium scale rice polisher of 2.5 t/h and to improve its performance for producing the clean rice with high quality. The maximum internal pressure, broken rice ratio. whiteness in the rice polisher were investigated, and the effects of outlet resistance, water spraying rate, shaft revolution speed and rice moisture content on the polishing performance were analyzed to find out proper operating conditions. The conclusions of this study were as follows: 1. In the performance evaluation of the polisher, the broken rice ratio increment of 0.1%, the max. internal pressure of about 11 N/${cm}^2$, and whiteness increment of 2.2~3.7 resulted at the conditions of 20 PS driving power, 950 rpm, 150 cc/min water spraying rate, 44.1 Nㆍcm outlet resistance and about 15% rice moisture content. 2. Though max. internal pressure and whiteness at the 17% rice moisture content were higher than those at the 15% moisture content under the same operating conditions of the polisher, but the broken rice rate at the 17% moisture content was absolutely low compared with that at 15% moisture content. The water spraying effect to reduce broken rice and to increase whiteness was much significant at the 15% moisture content not significant at 17% moisture content. 3. The main parameter of the performance was outlet resistance, and low resistance of about 44.1 Nㆍcm was recommended at the polisher. 4. The proper water spraying rate in the polisher was about 150 cc/min. 5. As the shaft revolution speed decreased from 950 rpm and 800 rpm to 650 rpm, the broken rice ratio increased and whiteness decreased. 6. As the driving power of the polisher increased from 20 PS to 30 PS, the max. internal pressure decreased by about 1~2.5 N/${cm}^2$ and whiteness increased by about 1~2, but the broken rice rate was not changed. 7. The proper operating conditions of the polisher seemed to be the revolution speed of 800-950 rpm, the water spraying rate of about 150 cc/min, the oulet resistance of about 44.1 N.cm and 30 PS driving power.

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Effect of High Carbohydrate Intakes on the Obesity Index, Blood Pressure, and Blood Lipid Levels in Patients with Cardiovascular Disease

  • Lee, Seung-Min;Ahn, Hyang-Sook;Lee, Lil-Ha
    • Journal of Nutrition and Health
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    • v.30 no.4
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    • pp.451-457
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    • 1997
  • This study was designed to investigate the effect of the ratio of energy from carbohydrate to total calories on dietary intake, obesity index, blood pressure, and blood lipid content in cardiovascular disease patients over 35 years old. A total of 552(227 male, 325 female) subjects were divided into three groups according to carbohydrate/total energy ratio : carbohydrate ratios below 25 percent were in the low carbohydrate group( <61.1%), between 25 and 75 percent carbohydrate were medium($\geq$61.1-<74.7%), and higher than 75 percent were in the high carbohydrate group($\geq$74.7%). The anthropometric data, nutrient intake, serum lipid levels, and blood pressure of each group were compared with one another. For men and women with high carbohydrate intakes, Inadequate nutritional intake was observed. Abdominal fat accumulation and blood TC level for men in the high carbohydrate group were higher than in medium or low carbohydrate groups. Therefore, it seems that high carbohydrate intake may produce adverse effects on abdominal fat accumulation and blood lipid patterns. Blood pressure, however, was significantly higher for women in low and high carbohydrate groups than in medium carbohydrate group. These results suggest that extremely high and low carbohydrate intake may raise the risk of cardiovascular disease and that it is necessary to consume nutritionally balanced meals. This can be done by controlling the ratio of dietary carbohydrate at a medium level in order to prevent and/or to reduce the risk.

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Numerical Study on Flow Characteristics of Hollow Fiber Membrane Module for Water Recovery Cooling Tower (수분회수 냉각탑에 적용되는 중공사막 모듈의 유동특성에 관한 수치해석적 연구)

  • Park, Sang Cheol;Park, Hyun Seol;Lee, Hyung Keun;Shin, Weon Gyu
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.41 no.8
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    • pp.537-544
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    • 2017
  • The purpose of this study is to analyze the flow characteristics when a staggered hollow fiber membrane module is modeled as a porous medium. The pressure-velocity equation was used for modeling the porous medium, using pressure drop data. In terms of flow characteristics, we compared the case of the "porous medium" when the membrane module was modeled as a porous medium with the case of the "membrane module" when considering the original shape of the membrane module. The difference in pressure drop between the "porous medium" and "membrane module" was less than 0.6%. However, the maximum flow velocity and mean turbulent kinetic energy of the "porous medium" were 2.5 and 95 times larger than those of the "membrane module," respectively. Our results indicate that modeling the hollow fiber module as a porous medium is useful for predicting pressure drop, but not sufficient for predicting the maximum flow velocity and mean turbulent kinetic energy.

Characterization of depth filter media for gas turbine intake air cleaning

  • Park, Young Ok;Hasolli, Naim;Choi, Ho Kyung;Rhee, Young Woo
    • Particle and aerosol research
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    • v.5 no.4
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    • pp.159-170
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    • 2009
  • A depth filter medium was newly designed in order to achieve high collection of dust and low pressure drop in this work. Multilayer depth filter media consist of an upstream layer of highly porous structure which allows particles to pass through and to follow by one or more downstream layers to hold the particles inside the media. For each filter media, flat sheet and pleated module were made of newly developed depth filter media and filter media of commercial products. Commercial depth filter cartridge for gas turbine air intake cleaning were used as reference for filtration area and pleat geometry of pleated modules. This work attempts to evaluate and compare the newly developed depth filter medium and two commercial filter media in terms of filtration parameters such as air permeability, initial pressure drop, particle retention and pressure drop variation with dust loading. According to the close examination the newly developed depth filter showed better performance compared to the commercial depth filter media.

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The effects of topography on local wind-induced pressures of a medium-rise building

  • Hitchcock, P.A.;Kwok, K.C.S.;Wong, K.S.;Shum, K.M.
    • Wind and Structures
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    • v.13 no.5
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    • pp.433-449
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    • 2010
  • Wind tunnel model tests were conducted for a residential apartment block located within the complex terrain of The Hong Kong University of Science and Technology (HKUST). The test building is typical of medium-rise residential buildings in Hong Kong. The model study was conducted using modelling techniques and assumptions that are commonly used to predict design wind loads and pressures for buildings sited in regions of significant topography. Results for the building model with and without the surrounding topography were compared to investigate the effects of far-field and near-field topography on wind characteristics at the test building site and wind-induced external pressure coefficients at key locations on the building facade. The study also compared the wind tunnel test results to topographic multipliers and external pressure coefficients determined from nine international design standards. Differences between the external pressure coefficients stipulated in the various standards will be exacerbated when they are combined with the respective topographic multipliers.

Effect of postulated crack location on the pressure-temperature limit curve of reactor pressure vessel

  • Choi, Shinbeom;Surh, Han-Bum;Kim, Jong-Wook
    • Nuclear Engineering and Technology
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    • v.51 no.6
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    • pp.1681-1688
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    • 2019
  • In accordance with ASME Boiler and Pressure Vessel (B&PV) Code Sec.XI Appendix. G, a postulated crack is located at the beltline of a reactor pressure vessel because the neutron flux at the beltline is higher than elsewhere. This means that the distance between the core and the semi-spherical bottom head is longer than the distance between the core and the cylindrical beltline. However, several Small and Medium sized Reactors have bottom heads with diverse shapes, including dished or semi-elliptical shapes, to satisfy the requirement and performance. So, the aim of this paper is to evaluate the effect of crack location on Pressure-Temperature limit curve. To do this, two types of postulated crack location, such as beltline and semi-elliptical bottom head, were adopted to derive the Pressure-Temperature limit curve. Also, parametric studies for neutron flux, crack shape and so on were performed. As a result, core critical temperature of semi-elliptical bottom head is found to higher than that of beltline even when they have same values of thickness and neutron flux. This result will be useful to enhance the understanding of Pressure-Temperature limit curve.

Factors Affecting the Application of Managerial Accounting in Small and Medium-Sized Enterprises in Vietnam

  • NGUYEN, Co Trong
    • The Journal of Asian Finance, Economics and Business
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    • v.8 no.9
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    • pp.313-319
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    • 2021
  • The article analyzes the impact of factors affecting the use of management accounting in small and medium-sized firms in Vietnam, which adds to the empirical evidence on these factorsThe survey results collected 328 questionnaires using a questionnaire survey of managers at all levels, chief accountants, and accountants of 89 small and medium firms in Vietnam. Some questionnaires were invalid due to many blank cells, hence the author chose to use 315 questionnaires. Quantitative research was carried out with SPSS 25 software. Research results show that five factors have a positive influence on the application of management accounting including Competitive pressure, Decentralization of responsibility, Application of information technology, the level of interest of managers, and the quality of human resources, in which the application of information technology and competitive pressure are the factors that have the strongest influence on the application of management accounting in small and medium enterprises in Vietnam. Based on the findings of the study, the author has proposed recommendations to help small and medium-sized businesses improve their ability to successfully apply management accounting techniques, thereby improving their competitiveness and efficiency performance and contributing to the long-term sustainability of their businesses.

Optimum Design of a Compact Heat Exchanger with Foam Metal Insertion (발포금속을 삽입한 밀집형 열교환기 최적 설계)

  • 이대영;진재식;강병하
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.13 no.7
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    • pp.612-620
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    • 2001
  • The optimum design of a heat exchanger with porous media insertion is studied in this paper. It is considered that the aluminum foam metal is inserted in a flat plate channel and air flows through it. The influence of the microstructure of the foam metal on the pressure drop and heat transfer is investigated utilizing previous analytical results and existing correlation equations. Design parameters are identified as the unit-cell size and the ligament thickness of the porous medium, and their effects are examined. The results show that there exists optimum microstructure of the porous media maximizing heat transfer with a constant pressure drop. When the increase in the pressure drop is within a practically acceptable range, the increase in the heat transfer is dominated by the increase in the heat transfer area due to the porous medium insertion. Consequently, among the porous media with a constant pressure drop, the heat transfer is maximized with a microstructure with maximum specific surface area.

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MOLECULAR GAS PROPERTIES UNDER ICM PRESSURE IN THE CLUSTER ENVIRONMENT

  • LEE, BUMHYUN;CHUNG, AEREE
    • Publications of The Korean Astronomical Society
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    • v.30 no.2
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    • pp.491-494
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    • 2015
  • We present 12CO (2-1) data for four spiral galaxies (NGC 4330, NGC 4402, NGC 4522, NGC 4569) in the Virgo cluster that are undergoing different ram pressure stages. The goal is to probe the detailed molecular gas properties under strong intra-cluster medium (ICM) pressure using high-resolution millimeter data taken with the Submillimeter Array (SMA). Combining this with Institut de RadioAstronomie $Millim{\acute{e}}trique$ (IRAM) data, we also study spatially resolved temperature and density distributions of the molecular gas. Comparing with multi-wavelength data (optical, $H\small{I}$, UV, $H{\alpha}$), we discuss how molecular gas properties and star formation activity change when a galaxy experiences $H\small{I}$ stripping. This study suggests that ICM pressure can modify the physical and chemical properties of the molecular gas significantly even if stripping does not take place. We discuss how this affects the star formation rate and galaxy evolution in the cluster environment.

Competitive Pressure and Business Performance in East Java Batik Industry

  • SOEWARNO, Noorlailie;TJAHJADI, Bambang;PERMATANADIA, Devitania
    • The Journal of Asian Finance, Economics and Business
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    • v.7 no.12
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    • pp.329-336
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    • 2020
  • This study aims to assess the impact of competitive pressure and innovation capability on business performance in small- and medium-sized enterprises (SMEs) in the batik industry in East Java, Indonesia. Furthermore, this study explores the impact of competitive pressure on business performance through innovation capability as a mediating variable. This research was quantitative using primary data with questionnaire as a method of sampling collection. The measurement of the variables was captured using Likert scale. The respondents were small- and medium-sized enterprises (SMEs) in the batik industry in East Java Province, Indonesia. The sample totaled 254 subjects. The data analysis was done using SEM-PLS. The results of the study show that: 1) there was a positive direct impact of competitive pressure on business performance; 2) competition pressure positively influences innovation capability; 3) innovation capability positively influences business performance; and 4) innovation capability has a partial mediating role in the effect of competitive pressures on business performance. The findings of this study suggest that managers in SME's batik industry should increase their effort to cope with the high competitive pressure to increase the innovation capability, so that they can have an advantage to face successfully competitors, leading to higher business performance.