• Title, Summary, Keyword: Individual formulas

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Molecular Dynamics Simulation Study of the Transport Properties of Liquid Argon: The Green-Kubo Formula Revisited

  • Lee, Song-Hi
    • Bulletin of the Korean Chemical Society
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    • v.28 no.8
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    • pp.1371-1374
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    • 2007
  • The velocity auto-correlation (VAC) function of liquid argon in the Green-Kubo formula decays quickly within 5 ps to give a well-defined diffusion coefficient because the velocity is the property of each individual particle, whereas the stress (SAC) and heat-flux auto-correlation (HFAC) functions for shear viscosity and thermal conductivity have non-decaying, long-time tails because the stress and heat-flux appear as system properties. This problem can be overcome through N (number of particles)-fold improvement in the statistical accuracy, by considering the stress and the heat-flux of the system as properties of each particle and by deriving new Green-Kubo formulas for shear viscosity and thermal conductivity. The results obtained for the transport coefficients of liquid argon obtained are discussed.

Lipid Metabolism of Korean Breast-Fed Formula-Fed Infants (모유영양아와 인공영양아의 지질 대사)

  • 임현숙
    • Journal of Nutrition and Health
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    • v.27 no.5
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    • pp.429-441
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    • 1994
  • The difference in lipid metabolism between breast-fed(BF) and formula-fed(FF) infants were studied in 31 Korean infants at 1, 2 and 3 months postpartum. The formulas had more total lipids(TL), triglycerides(TG) and phospholipids and less cholesterol(CHOL) and free fatty acids(FFA) than the breast milk. The milk consumption of the FF infants was significantly greater than that of the BF infants with a wide individual variation. As a result, the FF infants appeared to consume more TL, TG and PL and less CHOL and FFA than the BF infants during 3 months. The lipid contents of the breast milk tended to decrease in due course of lactation, therefore the intake of lipids of BF infants was reduced during the first three month of lactation. The plasma TG and CHOL levels of infants at 3 month were not significantly different between the BF and FF infants, but the PL level of the BF infants was higher then that of the FF infants. The plasma levels of TG and CHOL were not significantly correlated with the intakes of TL, TG, CHOL, PL and FFA, respectively. The PL level, however, was positively correlated with the intakes of CHOL and FFA, respectively and negatively correlated with PL intake as well as 18 : 2w6 fatty acid content of the breast milk or the formulas. The fecal weight and fecal loss of TL of the FF infants were greater than those of the BF infants during 3 months, however, apparent lipids digestibility was not significantly different between the BF and FF infants. The fecal excretions of CHOL and bile acids of FF infants were substantially higher than those of BF infants during 3 months. New sterol balance showed a particularly large difference between the BF and FF infants. The value of the net sterol balance of the BF infants was negative, but that of the FF infants was positive. This study shows that the consumption pattern of various lipid components of BF and FF infants were different as a result of different lipid compositions between breast milk and formula. The significantly lower sterol balance of the BF infants than the FF infants may have been derived from the unique dietary characteristic of breast milk.

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A Study of Flood Runoff Variation by Travel Times Estimation Methods (도달시간 산정방법에 따른 홍수유출특성 변화에 관한 연구)

  • Park, Ki-Bum;Ko, Jin-Seuk;Jee, Hong-Gee
    • Journal of the Korean Association of Geographic Information Studies
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    • v.9 no.1
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    • pp.34-45
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    • 2006
  • In this study comparison estimates travel times with observed travel time. In generally, peak flood discharges decrease become travel times longer. It is closely related to storage constant for the watershed routing of a flood. There are so many empirical formulas available for the estimation of travel time, storage coefficients and lag time but results computed generally show great different depending on individual formulas. When calculated flood discharge depend on the travel times varying the discharge. In this study the Wichun travel time shorter optimization travel time than observed travel time for the rusa and memi. There are showed good results for flood discharges, water level and velocity of the memi at the Younggok.

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Estimating the urinary sodium excretion in patients with chronic kidney disease is not useful in monitoring the effects of a low-salt diet

  • Kim, Se-Yun;Lee, Yu Ho;Kim, Yang-Gyun;Moon, Ju-Young;Chin, Ho Jun;Kim, Sejoong;Kim, Dong Ki;Kim, Suhnggwon;Park, Jung Hwan;Shin, Sung Joon;Choi, Bum Soon;Lim, Chun Soo;Lee, Minjung;Lee, Sang-ho
    • Kidney Research and Clinical Practice
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    • v.37 no.4
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    • pp.373-383
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    • 2018
  • Background: Several epidemiologic studies have suggested that the urine sodium excretion (USE) can be estimated in lieu of performing 24-hour urine collection. However, this method has not been verified in patients with chronic kidney disease (CKD) or in an interventional study. The purpose of this study was to evaluate the usefulness of estimating USE in a prospective low-salt diet education cohort (ESPECIAL). Methods: A new formula was developed on the basis of morning fasting urine samples from 228 CKD patients in the ESPECIAL cohort. This formula was compared to the previous four formulas in the prediction of 24-hour USE after treatment with olmesartan and low-salt diet education. Results: Most previously reported formulas had low predictability of the measured USE based on the ESPECIAL cohort. Only the Tanaka formula showed a small but significant bias (9.8 mEq/day, P < 0.05) with a low correlation (r = 0.34). In contrast, a new formula showed improved bias (-0.1 mEq/day) and correlation (r = 0.569) at baseline. This formula demonstrated no significant bias (-1.2 mEq/day) with the same correlation (r = 0.571) after 8 weeks of treatment with olmesartan. Intensive low-salt diet education elicited a significant decrease in the measured USE. However, none of the formulas predicted this change in the measured urine sodium after diet adjustment. Conclusion: We developed a more reliable formula for estimating the USE in CKD patients. Although estimating USE is applicable in an interventional study, it may be unsuitable for estimating the change of individual sodium intake in a low-salt intervention study.

Bridge Pier Scour Protection by Sack Gabions (돌망태에 의한 교각세굴 방지)

  • Yun, Tae-Hun;Kim, Dae-Hong;Lee, Ji-Song
    • Journal of Korea Water Resources Association
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    • v.33 no.6
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    • pp.725-731
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    • 2000
  • Experimental studies were conducted in a clear water condition to investigate the functioning of a sack gabion as a scour countermeasure at bridge piers. For different sizes of fill materials of sack gabions no difference was observed in the initial movement of sack gabions. Significant factors on the dislodging of sack gabions are approaching flow depth and velocity, pier width, and thickness and length of sack gabions. It was observed that the stability of the sack gabions is increased in a collective body of riprap stones than the placement of individual riprap stone. The length of a sack gabion has significant effect on its initial movement and the stability of a sack gabion was found to be increased by lengthening the length of gabions. The experimental results were used to derive formulas sizing gabions for scour protection at bridge piers. piers.

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Design formulas for vibration control of taut cables using passive MR dampers

  • Duan, Yuanfeng;Ni, Yi-Qing;Zhang, Hongmei;Spencer, Billie.F. Jr.;Ko, Jan-Ming;Fang, Yi
    • Smart Structures and Systems
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    • v.23 no.6
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    • pp.521-536
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    • 2019
  • Using magnetorheological (MR) dampers in multiswitch open-loop control mode has been shown to be cost-effective for cable vibration mitigation. In this paper, a method for analyzing the damping performance of taut cables incorporating MR dampers in open-loop control mode is developed considering the effects of damping coefficient, damper stiffness, damper mass, and stiffness of the damper support. Making use of a three-element model of MR dampers and complex modal analysis, both numerical and asymptotic solutions are obtained. An analytical expression is obtained from the asymptotic solution to evaluate the equivalent damping ratio of the cable-damper system in the open-loop control mode. The individual and combined effects of the damping coefficient, damper stiffness, damper mass and stiffness of damper support on vibration control effectiveness are investigated in detail. The main thrust of the present study is to derive a general formula explicitly relating the normalized system damping ratio and the normalized damper parameters in consideration of all concerned effects, which can be easily used for the design of MR dampers to achieve optimal open-loop vibration control of taut cables.

Development of an Estimation Method for Travel Time (도달시간 산정 방법의 개발)

  • Jeong, Jong-Ho;Keum, Jong-Ho;Yoon, Yong-Nam
    • Journal of Korea Water Resources Association
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    • v.35 no.6
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    • pp.715-727
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    • 2002
  • The travel time of a flood through a river reach can be estimated by dividing the river length by the mean velocity with which the flood passes downstream. It is closely related to storage constant for the watershed routing of a flood. There are so many empirical formulas available for the estimation of travel time but the results computed generally show great different depending on individual formulas. In the present study, the mean velocity data computed in the process of water surface profile computation for a probability flood through more than 100 different river reaches were collected along with the mean river bed slope of each river reach. And then, a regression analysis is made between the mean river bed slope and the mean velocity, which showed a wide scatter along the mean regression curve, which appears to be due to the different in the magnitude of probability rainfall and size of watershed area. Therefore, methods have been developed to remove the effect of these factors and generalized empirical equation is proposed to relate the mean velocity to mean river bed slope of a reach. Hence, if the mean river bed slope of a river reach is estimated from the longitudinal river profile, the mean velocity can be computed by the generalized equation along with the probability rainfall and watershed area of the river reach under consideration, which leads to the estimation of travel time through a river reach.

Intakes of Energy, Protein, Lipid and Lactose in Korean Breast-Fed and Formula-Fed Infants (모유 영양아와 인공 영양아의 에너지, 단백질, 지방 및 유당 섭취)

  • 임현숙
    • Journal of Nutrition and Health
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    • v.26 no.3
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    • pp.325-337
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    • 1993
  • Korean breast-fed(BF) and formula-fed (FF) infants(n=31) were studied at their age of 1, 2 and 3 months to compare their intakes of energy, protein, lipid and lactose. Formulas had more energy, protein and lipid than breast milk, but the former had less lactose than the latter. The milk consumption of the FF infants was, however, greater than that of the BF infants with wide individual variation. As a result, the FF infants took in more energy, protein and lipid than the BF infants except lactose. The total daily caloric intakes(kcal/day) of the BF infants were 521.418 and 425 at their age of 1, 2 and 3 months respectively, and those of the FF infants were 676.752 and 723(at their age of 1, 2 and 3 months respectively). Daily protein intakes(g/days) of the BF infants were 9.5, 8.0 and 7.6 at their age of 1, 2 and 3 months respectively, and those of the FF infants were 13.9, 15.5 and 14.8(at their age of 1, 2 and 3 months respectively). The energy and protein of both the BF and the FF infants were deficient compared to the present Recommended Nutrient Allowances, and the deficiency of the BF infants was greater than that of the FF infants. But the energy intakes per kg of body weight of the FF infants at their age of 1 and 2 months were more than the present recommended energy allowances. And the protein intake per kg of body weight of the FF infant at the age of 1 month was the same as the present recommended protein allowances.

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Configuration and Performance Analyses for Conceptual Design of Small and Mid-Unmanned Aerial Vehicles (중소형 무인항공기 개념설계를 위한 형상 및 성능 분석)

  • Jeon, Byung-Il;Lee, Narae;Chang, Young-Keun
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.42 no.6
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    • pp.478-487
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    • 2014
  • The simplified performance analysis and initial configuration design are required for the successful development of UAV during the conceptual design, in which empirical formulas and trend equations are utilized for the UAV performance analysis. In the conceptual design phase various UAV configurations may be considered, however, it is very inefficient and unnecessary to consider all configurations for the conceptual design. In this study, the database for the fixed wing UAVs whose MTOW is between 50kg and 1,500kg was also constructed for the selection of configuration frequently used. The parametric analyses were performed for major performance parameters, and trend equations were developed through regression analyses for these individual performance parameters.

A Proposal of New Policies for Raising Effectiveness and Efficiency of Government Sponsored Loan for ICT SMEs (ICT 중소기업 정책융자사업 효과성·효율성 제고를 위한 정책적 제언)

  • Khoe, Kyung-Il
    • Journal of Digital Convergence
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    • v.14 no.11
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    • pp.107-113
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    • 2016
  • This paper proposes various policies for maximizing the performances of Government loan. In order to do so, this paper offers new 10 policies with results from analyzing a survey for the requirements of SMEs that were supported with Government loan program. Also this paper drives methods for finding new value indices and reforming formulas for quantifying some indices. On the other hand, this paper introduces financing methods using K-OTC and KONEX markets and presents three portal sites to provide information about Government sponsored loan matched to needs of an individual company. Also this paper improves the supplement points resulted from operating Government loan. In conclusion, these new policies will raise effectiveness and efficiency of Government loan programs and will contribute to achieving the goals which are establishing the foundation for growth in IT industry as well as IT SMEs, improving the quality of the national livelihood and promoting the growth of national economy.