• 한국자동차공학회논문집
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• 제6권6호
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• pp.113-131
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• 1998

The objective of the present study is to investigate the characteristics of the dividing flow in the laminar flow region. Using glycerine water solution(wt43%) for Newtonian fluid and the polymer of viscoelastic fluid(500wppm) for non-Newtonian fluid, this research investigates the flow state of the dividing tube in steady laminar flow region of the two dimensional dividing tube by measuring the effect of Reynolds number, dividing angle, and the flow rate ratio on the loss coefficient. In T- and Y-type tubes, the loss coefficients of the Newtonian fluid decreases in constant rate when the Reynolds number is below 100. The effect of the flow rate ratio on the loss coefficients is negligible. But when the Reynolds number is over 100, the loss coefficient with various flow rate ratios approach an asymptotic value. The loss coefficient of the non-Newtonian fluid for different the Reynolds number shows the similar tendency of the Newtonian fluid. And when the Reynolds number is over 300, the loss coefficient is approximately 1.03 regardless of flow rate ratio or the dividing angle. The aspect ratio does hardly influence the reattachment length and the loss coefficient of both Newtonian and non Newtonian fluid. The loss coefficient decreases as the Reynolds number increases. The loss coefficient of Newtonian fluid is larger than that of non-Newtonian fluid.

• 대한기계학회논문집B
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• 제32권1호
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• pp.39-46
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• 2008

The loss coefficient of the butterfly valve which allows partial opening of the valve at closed position and is applicable to the small-sized pipe system with the diameter of 1 inch was measured for the variation of the valve disk blockage ratio. Two different types of the valve disk configuration to adjust the blockage ratio were considered. One was the solid type valve disk of which the diameter was changed into the smaller size rather than the pipe diameter, and the other was the perforate type valve disk on which some holes were perforated. The results from two types of valve disk were compared to identify their characteristics in the loss coefficient distributions. The loss coefficient and the controllable angle of the valve disk were decreased exponentially with the decrease of the blockage ratio. In addition, the perforate valve disk had the effect on the higher loss coefficient rather than the solid type valve disk.

• 한국염색가공학회지
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• 제26권4호
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• pp.331-338
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• 2014

In this research, split-type complex yarn of 20:80, 40:60, 50:50 nylon6/polyester composition ratio was used in order to impose unique sense on split-type complex woven. After treating both split-type complex yarn of each ratio and its produced woven in alkali solution, we got the following results by checking physical properties based on alkali proportion and treatment time. Under the condition of NaOH 20% in this experiment, it took approximately double time 20% loss of weight. The loss of weight became high when polyester proportion of N/P(nylon6/polyester) composition ratio was low, in the same fineness yarn. Even though polyester proportion was low, the loss of weight was low when the fineness was high. N/P division was well processed at about 25% loss of weight under the condition of NaOH 20%, treatment temperature $50^{\circ}C$, and treatment time 60 minutes. The research provides that the loss of weight should be processed around treatment time 24 hours in the case of NaOH concentration 15%, and treatment time 15 hours in the case of NaOH concentration 18%, respectively, in order to achieve N/P woven division ratio of about 70%-80% in industrial fields.

• 한국터널지하공간학회 논문집
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• 제15권1호
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• pp.25-31
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• 2013

본 논문은 지하철 터널 유지관리 계측센서의 총 손망실율을 산정하기 위해 국내와 국외의 지하철 터널구조물에 설치되어 운영 중에 있는 유지관리 계측센서의 손망실 현황을 조사하고 분석을 실시하였다. 지하철 터널 유지관리 계측센서 설치 후 5~6년 경과된 시점을 기준하여 총 손망실율은 서울지하철5,6,7호선에서 14.2%, 서울지하철9호선1단계구간에서 14.8%, 영국의 Channel tunnel에서 13.9%로 모두 15%에 근접하게 나타났다. 따라서 지하철 터널 유지관리 계측센서의 총 손망실율은 잠정적으로 15%로 설정하여 설계에 반영하는 것이 타당한 것으로 판단되며, 향후 장기간의 경과년수에 따른 계측항목별 손망실율 연구가 필요할 것으로 판단된다.

• International Journal of Industrial Entomology and Biomaterials
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• 제8권1호
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• pp.101-106
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• 2004

The process of removal of gummy proteinous material sericin from silk is commonly called as degumming loss or boil-off loss ratio. In the present study, the boil-off loss ratio in the cocoon shells of twelve multivoltine${\times}$bivoltine hybrids and their parents were analysed. Inheritance pattern of boil-off loss ratio was analysed in crosses involving high and low boil-off loss parents, F$_1$s, F$_2$s and back-crosses by parent off spring regression analysis. Heterosis and heterobeltiosis was also analysed for this character, Highly significant (P＞0.01) variations were observed in eight out of ten multivoltine and two out of five bivoltine parents indicating the presence of genetic variation in the expression of boil-off loss ratio. Among F$_1$ hybrids, ten hybrids expressed significant (P＞0.01) variations when compared with control hybrid PM${\times}$NB$_4$D$_2$. Significant negative heterosis was expressed in three multi ${\times}$ bi hybrids viz., BL67${\times}$CSR$_{101}$, 96A${\times}$CSR$_{19}$ and 96C${\times}$CSR$_{19}$, which is desirable for this character, whereas expression of heterobeltiosis was significant only with one hybrid, 96C${\times}$CSR$_{18}$ in desired direction. Studies on inheritance pattern showed that the character is heritable and contribution percentage of female and male in the ratio of 50.9: 49.1 and it appears that both the parents are influencing in the expression of boil-on loss ratio in silkworm. Based on the overall performance and evaluation by multiple trait evaluation index and also considering the expression of the boil-off loss ratio three hybrids vix., BL67 ${\times}$ CSR$_{101}$, 96A${\times}$CSR$_{19}$ and 96C${\times}$CSR$_{18}$ were found superior and recommended for commercial exploitation.n.ion.n.

• 한국자동차공학회논문집
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• 제9권1호
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• pp.112-121
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• 2001

In this paper, an engine-CVT integrated control algorithm is suggested by considering the powertrain loss, inertia torque and the CVT ratio response lag. The integrated control algorithm consists of (1) the optimal engine power calculation and (2) determining of the optimal throttle valve opening and the optimal CVT ratio. The optimal engine power is obtained by compensating the inertia torque due to the CVT ratio change and the powertrain loss that is calculated iteration procedure. In addition, an algorithm to compensate the effect of the CVT ratio response lag on the drive torque is suggested by the engine speed compensation causing the increased optimal CVT ratio. Simulation results show that the engine-CVT integrated control algorithm developed in this study makes it possible to obtain better engine operation on the optimal operating line, which results in the improved fuel economy while satisfying the driver's demand.

• 대한기계학회논문집B
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• 제32권11호
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• pp.817-823
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• 2008

A pin fin with variable fin base thickness is optimized based on the ratio of heat loss to the maximum heat loss using a two-dimensional analytic method. The temperature profile along the normalized radius position in the fin is presented. For fixed fin outer radius, the optimum heat loss, fin length and efficiency as a function of fin base thickness, outer radius, convection characteristic numbers ratio and ambient convection characteristic number are presented. One of the results shows that the effect of fin outer radius and ambient convection characteristic number on the optimum fin length is remarkable.

• 한국병원경영학회지
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• 제6권2호
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• pp.156-172
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• 2001

Financial ratio indicators of the 73 sample hospitals provided by the Korea Hospital Association in 1998-1999, together with the data by the Korea Health Industry Development Institute in 1007, were analysed to identify the financial structure and managerial performance of the profit/loss-making hospitals under the IMF. The major findings of this study were as belows. 1. Among the general characteristics, there was a statistical significance in the hospital location and the number of operating beds between profit-making hospitals and loss-making hospitals. 2. Financial ratio indicators of the profit-making hospitals were better than those of the loss-making hospitals. 3. Financial ratio indicators, including Liquidity, Performance Indicators and Growth Rate Indicators of profit-making hospitals, were better than those of loss-making hospitals except for Turnover Ratios under the IMF economic impasse.

• 한국병원경영학회지
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• 제8권3호
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• pp.118-142
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• 2003

This study is aimed at evaluating the financial structure of hospitals before and after the separation of prescription and drug dispensing policy started to be implemented in July 2000 and at making a suitable hospital managerial strategy through the verification of the factors which have effect on their profitability. This study investigated the hospitals which have passed the accredition review to be designated as a accredited training hospital each year for three years from 1999 to 2001. Those hospitals were selected from members of the Korea Hospital Association. 106 hospitals were targeted for analysis except for the hospitals whose financial statements and managerial performance were not reported faithfully. The financial indicators used in this study were stability indicators(liability to total assets, ratio of debt to fund balance, fixed ratio), liquidity indicators(current ratio, quick ratio), activity indicators(total assets turnover, fixed assets turnover), profitability indicators(net profit to total assets, net profit to net worth, operating margin), and operating expenses to patient revenues indicators(drug and supplies costs/payroll/overhead expenses). The result of this study are as follows: First, the analysis of the increase of loss-making hospitals before and after. The separation of prescription and drug dispensing policy shows that the number of loss-making hospitals increase after the separation(22.6% before the separation; 31.1% after the separation). However, there was no significant statistical difference. Second, the analysis of operating expenses to patient revenues indicators showed that the ratio of drug and supplies cost became lower in all hospitals but the ratio of payroll/overhead expenses became higher. Additionally, the factor which have the greatest effect on profitability was operating expenses to patient revenues indicators (drug and supplies costs/payroll/overhead expenses). Third, the analysis of managerial performance by four types of loss-loss, loss-profit, profit-loss and profit-profit compared the results before the separation with those after the separation revealed as follows : Reliance on liability to total assets became higher in the profit-loss type($56.2%{\rightarrow}66.4%$), lower in the loss-profit type($82.7%{\rightarrow}74.5%$). Total assets turnover became higher in the profit-profit type($1.3{\rightarrow}1.5$), but lower in the loss-profit type($0.8{\rightarrow}0.7$). Operating margin decreased to minus 5.9% from 4.3% in the profit-loss type, but increased to 7.2% from minus 7.8% in the loss-profit type. Forth, operating expenses to revenues indicators showed that the increase of payroll was the biggest in the profit-loss type($39.2%{\rightarrow}49.9%$) and that overhead cost decreased in the loss-profit type but that rather increased in other types.

• Journal of Biosystems Engineering
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• 제43권4호
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• pp.320-330
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• 2018

Purpose: The aim of this study was to investigate the harvesting performance of a prototype small combine for buckwheat and adlay. Methods: The prototype small combine was designed and constructed. Its ratio of grain loss, ratio of output components in the grain outlet, and field capacity for harvesting buckwheat and adlay were analyzed through field tests. Results: The prototype small combine required a working width of about 0.6 to 0.7 m to harvest buckwheat. The maximum travel speed was about 0.36 m/. The total ratio of grain loss was about 21.6%, which consisted of 8.8% at the header and 12.8% at the dust outlet. The grain and the material other than grain (MOG) ratios at the grain outlet were 94.1% and 5.9% respectively. In the case of adlay harvest, the maximum working width was about 1.2 m, that is, two rows. The range of maximum travel speed was about 0.45 to 0.46 m/s. When adlay was harvested in one row, the total ratio of grain loss ranged from 36.3 to 42.8% according to the cutting height. The cutting height of 30 cm resulted in a higher total ratio of grain loss than 60 cm and 90 cm. When the cutting height was 60 cm, there was no significant change in the total ratio of grain loss according to the number of working rows and the stage of the primary transmission shift. The total ratio of grain loss ranged from 35.2 to 37.7%. The grain and the MOG ratios at the grain outlet ranged from 93.1 to 95.8% and from 4.2 to 6.9%, respectively. No significant difference was observed in relation to cutting height, number of working rows, and the stage of the primary transmission shift. Conclusions: The prototype small combine for harvesting miscellaneous cereal crops showed good potential for the efficient harvesting of buckwheat and adlay. However, to improve the harvesting performance, there seems to be a need to develop new crop varieties suitable for machine-based harvesting and improve the transmissions, reels, separation/cleaning systems.