• 제목/요약/키워드: scale effects

검색결과 6,744건 처리시간 0.039초

Turbulence effects on surface pressures of rectangular cylinders

  • Li, Q.S.;Melbourne, W.H.
    • Wind and Structures
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    • 제2권4호
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    • pp.253-266
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    • 1999
  • This paper presents the effects of free-stream turbulence on streamwise surface pressure fluctuations on two-dimensional rectangular cylinders. Particular attention is given to possible effects of turbulence integral scale on fluctuation and peak pressures. The mean, standard deviation, peak pressure coefficients, spectra and cross-correlation of fluctuating pressures were measured to investigate the nature of the separation and reattachment phenomenon in turbulent flows over a wide range of turbulence intensity and integral scale.

대형 유통업체 영업 규제가 농수산업에 미치는 영향 분석 (An Analysis of the Effects of Large-scale Retailer Operation Regulations on Agriculture and Fisheries)

  • 김동환;류상모
    • 유통과학연구
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    • 제12권2호
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    • pp.73-79
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    • 2014
  • Purpose - The Korean government has revised the distribution industry development law to regulate large-scale retailer operations to protecting medium- and small-scale retailers and traditional markets. According to the revised law, large-scale retailers must follow regulations on operating hours and compulsory store closures two days per month. Based on the revised distribution industry development law, most local governments regulate operation hours and they have adopted compulsory closure programs for large-scale retail stores. However, it is argued that fresh food producers suffer from a decrease in sales based on the compulsory closure of stores operated by large-scale retailers. Large-scale retailers reduce their fresh food orders from agricultural and fishery producers because of the compulsory store closures. Fresh food producers also suffer from a decrease in prices because reduced orders lead to a decrease in auction prices based on the availability of excess goods in wholesale markets. This paper investigates the effects of operation regulations for large-scale retailers on agricultural producers by surveying agricultural and fishery producer organizations. Research design, data, methodology - A survey was conducted on 117 producer organizations of fruits and vegetables, cereals, fisheries, and livestock products from September 10 to October 4, 2012. Survey items are annual sales, shares of sales accounted for by large-scale retailers, reduction of orders and prices from large-scale retailers, methods to deal with the sales reduction, unfair trade practices of large-scale retailers, opinion of the large-scale retailer regulations, and so on. The average sales of the sampled producer organizations are 13.7 billion won and the average share of sales accounted for by large-scale retailers is 35.4%. Results - Survey results show that the sample producer organizations' sales decreased 10.1% because of the compulsory closures of stores operated by large-scale retailers. It is estimated that the total sales of producer organizations decreased 371.2 billion won because of the regulations on the operation of large-scale retailers. In addition to the direct effect of a sales decrease due to order reduction, agricultural and fishery producer organizations suffered from the secondary effect of price reduction in wholesale markets. When orders from large-scale retailers decreased, most agricultural and fishery producer organizations shipped redundant products to wholesale markets, decreasing auction prices. It was estimated that the price received decreased 21.9% when sold in other marketing channels. As producer organization sales decreased, it was reported that the labor force employed by producer organizations also decreased by 15.1%. Therefore, we can conclude that the regulations for large-scale retailer operations resulted in negative impacts on agricultural producers. Conclusions - Although the sales reduction due to the regulations for large-scale retailer operations are not great, the cumulative effects due to the continued compulsory closure of stores operated by large-scale retailers could be great. This paper suggests governmental programs that could help agricultural producer organizations to find new and effective marketing channels such as direct marketing, farmers' markets, exports, Internet shopping, and so on.

중풍경직에 전침, TENS 및 신경근 자극기의 효과에 대한 연구 (Antispastic Effects of Electroacupuncture, TENS and NMEs in Stroke Patient)

  • 김용석
    • Journal of Acupuncture Research
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    • 제17권2호
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    • pp.209-220
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    • 2000
  • Spasticity, an abnormal increase in resting muscle tone, is one of the most common symptoms of stroke, and its management is becoming a major issue in rehabilitation. The aims of this study are to determine the effects of electroacupuncture(EA), TENS and neuromuscular electric stimulation(NMES) on spasticity, as well as the possibility of tissue comliance method as a spasticity scale. 45 stroke patients participated in a study of the effects on hemiplegic spasticity of EA, TENS and NMES. Spasticity was measured by modified Ashworth scale on the upper extremity and tissue compliance measurement, penetration mm/kg, on Susamni(LI10) area at just before and after stimulation, and 30 minutes, 1 hour, 2 hours and 24 hours after stimulation. The acupuncture points were applied to Kokchi(LI11), Susamni(LI10), Hapkok(LI4) and Oegwan(TE5) of the affected limb. The electrodes were placed unilaterally on LI11 to LI10 and TE5 to LI4. EA with biphasic wave, 60Hz, 0.4 msec pulse duration and low intensity was applied continuously for 20 minutes. TENS with high frequency, low intensity was applied. NMES was applied with spasticity program for 20 minutes. Each electric stimulation was done on extensor muscles group of forearm for 20 minutes. EA and NMES groups were found to produce a statistically significant decrease(p〈0.05) of spasticity and these effects lasted up to 30 minutes after stimulation. There was no definite correlation between the modified Ashworth scale and tissue compliance measurement. But tissure compliance method was found to be possible as a quantitative measurement on spasticity. There was no significant correlation between the effects of EA and NMES and the characteristics of patient, but significant correlation between the effects of EA and NMES and the modified Ashworth scale.

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Investigation of surface pressures on CAARC tall building concerning effects of turbulence

  • Li, Yonggui;Yan, Jiahui;Chen, Xinzhong;Li, Qiusheng;Li, Yi
    • Wind and Structures
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    • 제31권4호
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    • pp.287-298
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    • 2020
  • This paper presents an experimental investigation on the surface pressures on the CAARC standard tall building model concerning the effects of freestream turbulence. Two groups of incidence turbulence are generated in the wind tunnel experiment. The first group has an approximately constant turbulence intensity of 10.3% but different turbulence integral scale varying from 0.141 m to 0.599 m or from 0.93 to 5.88 in terms of scale ratio (turbulence integral scale to building dimension). The second group presents similar turbulence integral scale but different turbulence intensity ranging from 7.2% to 13.5%. The experimental results show that the mean pressure coefficients on about half of the axial length of the side faces near the leading edge slightly decrease as the turbulence integral scale ratio that is larger than 4.25 increases, but respond markedly to the changes in turbulence intensity. The root-mean-square (RMS) and peak pressure coefficients depend on both turbulence integral scale and intensity. The RMS pressure coefficients increase with turbulence integral scale and intensity. As the turbulence integral scale increases from 0.141 m to 0.599 m, the mean peak pressure coefficient increases by 7%, 20% and 32% at most on the windward, side faces and leeward of the building model, respectively. As the turbulence intensity increases from 7.2% to 13.5%, the mean value of peak pressure coefficient increases by 47%, 69% and 23% at most on windward, side faces and leeward, respectively. The values of cross-correlations of fluctuating pressures increase as the turbulence integral scale increases, but decrease as turbulence intensity increases in most cases.

축소모델과 실모델 면진베어링의 성능실험에 관한 연구 (A Study on Testing of 1/4-scale and Full-size Seismic Isolation Bearings)

  • 정민기;정지만;김두훈
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 1996년도 춘계학술대회논문집; 부산수산대학교, 10 May 1996
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    • pp.194-202
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    • 1996
  • An approach to increase the seismic resistance of large structures is to reduce the seismic forces, to which structures are subjected by base isolation systems. The anti-seismic performance of base-isolated beatings has been verified experimentally by shaking table tests. However, it may be difficult to perform the tests for the full-scale beatings of base-isolated structures. Therefore, the test program was designed to evaluate the reliability and properties of the beatings under a range of loading conditions including axial stress, loading frequency and direction, and temperature. The effects of scale were also evaluated by comparing the results of the 1/4-scale beatings with those from the full-scale bearings, and the ultimate behavior of both types of bearings with evaluated through a series of roll-out tests. This report draws comparisons among the different tests and bearings to determine the importance of various factors including load history, axial stress, and frequency. Comparisons between the 1/4-scale bearings were difficult because of the scaling effects in manufacturing and thermal radiation, but qualitative results from the 1/4-scale bearings can certainly be extrapolated the full-scale bearings.

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Meso-Scale Approach for Prediction of Mechanical Property and Degradation of Concrete

  • Ueda, Tamon
    • Corrosion Science and Technology
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    • 제3권3호
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    • pp.87-97
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    • 2004
  • This paper presents a new approach with meso scale structure models to express mechanical property, such as stress - strain relationships, of concrete. This approach is successful to represent both uniaxial tension and uniaxial compression stress - strain relationship, which is in macro scale. The meso scale approach is also applied to predict degraded mechanical properties of frost-damaged concrete. The degradation of mechanical properties with frost-damaged concrete was carefully observed. Strength and stiffness in both tension and compression decrease with freezing and thawing cycles (FTC), while stress-free crack opening in tension softening increases. First attempt shows that the numerical simulation can express the experimentally observed degradation by introducing changes in the meso scale structure in concrete, which are assumed based on observed damages in the concrete subjected to FTC. At the end applicability of the meso scale approach to prediction of the degradation by combined effects of salt attack and FTC is discussed. It is shown that clarification of effects of frost damage in concrete on corrosion progress and on crack development in the damaged cover concrete due to corrosion is one of the issues for which the meso scale approach is useful.

암환자의 치료 부작용, 가족지지, 삶의 질과의 관계 연구 (The Relationships of Treatment Side Effects, Family Support, and Quality of Life in Patient with Cancer)

  • 허혜경;김대란;김대화
    • 대한간호학회지
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    • 제33권1호
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    • pp.71-78
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    • 2003
  • Purpose: The study was done to identify the relationship of treatment side effects, family support, and quality of life in patients with cancer, and factors influencing quality of life. Method: A convenience sample of 106 patients who were receiving cancer treatment at W hospital were interviewed using the Side Effects scale by Hur, Family Support scale by Kang, and QOL scale by Ro. Result: Results indicate that women experienced more severe side effects than men. There was a negative relationship between side effects and quality of life, and a positive relationship between family support and quality of life. The most bothersome side effects were changes in taste and appetite, followed by general weakness and fatigue. Side effects such as loss of hair, nausea, dizziness, numbness, pins and needles in fingers and toes, and dry mouth were also experienced. General weakness and family support were analysed as to whether they were factors influencing quality of life. Conclusion: The results revealed that relieving general weakness should be given high priority in nursing interventions for patients undergoing cancer treatment. In addition, nursing programs should be developed that can reinforce family support.

아동후기 초등학교 학생의 부정적 생활사건, 자아 존중감, 사회적 지원과 부적응에 관한 종단연구 (A Longitudinal Study of Negative Life Events, Self-Esteem, Social Support, and Maladjustment among Late Elementary School Children)

  • 심희옥
    • 아동학회지
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    • 제19권2호
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    • pp.35-47
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    • 1998
  • Negative life events, self-esteem, perceived social support, and maladjustment were studied longitudinally among late elementary children. Subjects were 241 boys and girls for depression and 258 for antisocial behavior. The instruments were the Adolescent Perceived Events Scale, the Rosenberg Self-Esteem Scale, the Social Support Scale for Children, the Revised Korean Version of the Center for Epidemiologic Studies' Depression Scale, and the Antisocial Behavior Scale. The results showed that the way variables were reciprocally related to one another in patterns over a period of one year differed by internal and external adjustment. For depression, depression at Time 1 had effects on self-esteem, social support, and depression at Time 2. For antisocial behavior, negative life events at Time 1 influenced negative life events, self-esteem, social support, and antisocial behavior at Time 2. The findings were discussed in relation to the effects of negative life events, self-esteem, and perceived social support on maladjustment.

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강우상태에 의한 소수력발전소 설계인자의 영향 (The Effects of Design Parameters for Small Scale Hydro Power Plant with Rainfall Condation)

  • 박완순;이철형
    • 한국태양에너지학회 논문집
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    • 제28권1호
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    • pp.43-49
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    • 2008
  • The effects of design parameters for small scale hydro power(SSHP) plants due to rainfall condition have been studied. The model to predict hydrologic performance for SSHP plants is used in this study. The results from analysis for rainfall conditions based on Weibull distribution show that the capacity and load factor of SSHP site had large difference between the variation of shape and scale parameter. Especially, the hydrologic performance of SSHP site due to variation of shape parameter varied more sensitive than the case of variation of scale parameter. And also, the methodology represented in this study can be used to decide the primary design specifications of SSHP sites.

Investigation of the effects of free-stream turbulence on wind-induced responses of tall building by Large Eddy Simulation

  • Li, Q.S.;Hu, G.;Yan, Bo-Wen
    • Wind and Structures
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    • 제18권6호
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    • pp.599-618
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    • 2014
  • In this study, a square rectangular tall building is considered to investigate the effects of turbulence integral length scale and turbulence intensity on the along-wind responses, across-wind responses and torsional responses of the tall building by Large Eddy Simulation (LES). A recently proposed inflow turbulence generator called the discretizing and synthesizing random flow generation (DSRFG) approach is applied to simulate turbulent flow fields. It has been proved that the approach is able to generate a fluctuating turbulent flow field satisfying any given spectrum, desired turbulence intensity and wind speed profiles. Five profiles of turbulence integral length scale and turbulence intensity are respectively generated for the inflow fields by the DSRFG approach for investigating the effects of turbulence integral length scale and turbulence intensity on the wind-induced responses of the tall building. The computational results indicate that turbulence integral length scale does not have significant effect on the along-wind (displacement, velocity and acceleration) responses, across-wind displacement and velocity responses, while the across-wind acceleration and torsional responses vary without a clear rule with the parameter. On the other hand, the along-wind, across-wind and torsional responses increase with the growth of turbulence intensity.