• Title/Summary/Keyword: Stratification effect

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A Study of College Students' Consumption Behavior from the Midwest(Yunnam) in China(Part I): The Effects of Materialism on the Consumers's Attitudes and Clothing Purchase Behaviors (중국 중서부 지역(운남성) 대학생들의 소비행동 연구(제1보): 물질주의성향에 따른 소비자태도와 의복구매행동분석)

  • Lee, Okhee;Kang, Youngeui
    • Journal of Fashion Business
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    • v.18 no.1
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    • pp.50-65
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    • 2014
  • This study investigates the effect of demographics and materialism on the consumers's attitudes and clothing purchase behaviors. The subjects compose of 302 college students living in Yunnam, China. The mean, ANOVA, factor analysis, Duncan test were used for statistics analysis. According to our results, the factors of materialism, symbolic consumptions, and attitude toward fashion luxury products are identified: three factors of materialism (success symbols, practical living, and happiness pursuing), three factors of symbolic consumption (conspicuous, hedonic, communication), and five factors of attitudes toward fashion luxury products (quality, involvement, ostentation, luxurious aspect, pleasure). Among the demographics, gender, income, social stratification, father's education and job influenced the symbolic consumption, and desire's fashion luxury products. In addition, gender, income, social stratification, father's education and job influence the clothing selection standards and the extent of using fashion informations. Lastly, symbolic consumption, attitudes toward fashion luxury products, and apparel purchasing behaviors all proven to be significantly different among the 3 groups of materialism.

Study on the Characteristics of Cylinder Wake Placed in Thermally Stratified Flow(III) - Turbulent Dispersion from a Line Heat Source- (열성층유동장에 놓인 원주후류의 특성에 대한 연구 (3) -선형열원으로부터의 난류확산-)

  • 김경천;정양범
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.19 no.5
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    • pp.1300-1307
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    • 1995
  • The effect of thermal stratification on the turbulent dispersion from a fine cylindrical heat source was experimentally examined in a wind tunnel with and without a strong temperature gradient. A 0.5 mm dia. nichrome wire was used as a line heat source. Turbulent intensities, r.m.s. value of temperature and convective heat fluxes were measured by using a hot-wire and cold-wire combination probe. The results show that the peack value and the spread of the vertical turbulent intensity for the stratified case are far lower than those in the neutral case, which indicates that the stable temperature gradient suppresses the vertical velocity component. All of the third order moments including heat fluxes measured in the stable condition have very small values than those of the neutral case. This nature suggests that the decrease of scalar fluctuations in the stably stratified flow is mainly due to the suppression ofthe turbulent diffusion processes by the stable stratification. A simple gradient model with a composite timescale which has a simple weighted algebraic mean between dynamic and thermal time scale yields reasonably good numerical values in comparison with the experimental data.

Potential of Fuel Stratification for Reducing Pressure Rise Rate in HCCI Engines (HCCI 기관에 있어서의 층상 흡기를 통한 압력 상승률 저감에 대한 연구)

  • Lim, Ock-Taeck
    • Journal of the Korean Institute of Gas
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    • v.14 no.6
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    • pp.7-14
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    • 2010
  • This study investigated the effect on reducing the pressure rise rate(PRR) in HCCI Engine by the variation of mixing ratio in the pre-mixture of DME and n-Butane that has different auto-ignition characteristics. In addition to measure of gas pressure in the engine cylinder, chemiluminescence image using the optical accessible engine and numerical analysis with multi-zones model were used to assess the combustion at each local area in the combustion chamber. The maximum PRR changes depending on mixing condition of DME and n-Butane. When DME is stratified and n-Butane is distributed uniformly, maximum PRR becomes lowest which is about 0.25MPa/ms and it corresponds to 5deg. retarding of CA50.

Study on germination rate enhancement and seedling raising-method development on Sorbus commixta Hedl. (마가목 종자(種子)의 발아율(發芽率) 향상(向上) 및 육묘기술(育苗技術))

  • Lee, Seong-Yeal;Cho, Su-Hyun;Noh, Joon-Hyen;Youn, Jong-Tack;Yu, Chang-Yeon;Lee, Jin-Ha;Kim, Jong-Dai
    • Korean Journal of Medicinal Crop Science
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    • v.11 no.2
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    • pp.135-142
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    • 2003
  • This study was conducted to clarify on germination rate enhancement effect and to develope the growing seedling method on Sorbus commixta Hedl. The results were follows; The optimum temperature of stratification and germination of mountain ash was $5^{\circ}C$ the seed germination rate in wet stratification with sand at $5^{\circ}C$ for 90 days was 22.6% and the highest germination of 78.9% was observed when seed was soaked in BA 200ppm for 20 minute after stratification for 90 days at $5^{\circ}C$. The highest germination of large chinese hawthorn was 11.1% when seed was soaked BA 50ppm for 20 minute after stratification 90 days at $5^{\circ}C$. Emergence ratio in box raising seedling and pot seedling showed high, 93 and 95%. Root length and dry root weight in pot seedling for 50 days showed higher than that of direct seedling and box raising seedling, Plant height and dry leaf weight in box raising seedling showed higher than that of pot seedling and direct seedling. The growth increment of seedling was high between 40 days and 50 days after seedling. The excellent seedling of mountain ash was produced in pot seedling for 50 days.

Effect of Stabilizing Thermal Gradients on Natural Convection in a Completely Confined Rectangular Enclosure (안정온도구배가 밀폐용기내의 자연대류에 미치는 영향)

  • 김무현;이진호;장은구
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.13 no.6
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    • pp.1330-1338
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    • 1989
  • 본 연구에서는 직각밀폐용기의 수평경계면이 단열인 경우뿐만 아니라 등온 조건을 갖는 경우에 대해 실험적으로 연구하여 경계조건의 변화가 직각밀폐용기내 흐름 및 열전달에 미치는 영향, 특히 등온조건을 갖는 경우 수직 온도차에 따르는 안정온도 구배효과로 예상되는 흐름의 억제, 지연효과를 작종 물리적 변수들의 영향과 함께 세밀히 조사하였다.

Effect of supply air temperature and airflow rate on ventilation effectiveness in an underfloor air conditioning space (바닥취출 공조공간에서 급기온도 및 급기풍속이 환기효율에 미치는 영향)

  • 정광섭;한화택;홍승재
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.10 no.5
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    • pp.640-648
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    • 1998
  • A numerical study has been conducted to investigate the effect of inflow supply air temperature and velocity on ventilation effectiveness in an underfloor air conditioning space. A low Reynolds number k-$\varepsilon$ model is implemented to calculate steady state turbulent velocity distributions. A step-down injection method is used to calculate local and room mean ages from transient concentrations based on the concept of the age of air. Results show that there is a significant effect of Archimedes number on ventilation effectiveness especially for cooling conditions. Reynolds number shows relatively minor effect on velocity distribution and ventilation effectiveness especially for isothermal and heating conditions. It can be concluded that underfloor air conditioning system provides good ventilation characteristics for cooling conditions because of temperature stratification in the space.

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A Study on Buoyancy Effects in Double-Diffusive Convecting System(II) - Theoretical Study - (이중확산 대류계에서의 부력효과에 관한 연구(II) - 이론적 연구 -)

  • Hong, Nam-Ho;Kim, Min-Chan;Hyun, Myung-Taek
    • Journal of Ocean Engineering and Technology
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    • v.13 no.2 s.32
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    • pp.129-137
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    • 1999
  • The time of the onset of double-diffusive convection in time-dependent, nonlinear concentration fields is investigated theoretically. The initially quiescent horizontal fluid layer with a uniform temperature gradient experiences a sudden concentration change from below, but its stable thermal stratification affects concentration effects in such way to invoke convective motion. The related stability analysis, including Soret effect, is conducted on the basis of the propagation theory. Under the linear stability theory the concentration penetration depth is used as a length scaling factor, and the similarity transform for the linearized perturbation equations. The newlly obtained stability equations are solved numerically. The resulting critical time to mark the onset of regular cells are obtained as a function of the thermal Rayleigh number, the solute Rayleigh number, and the Soret effect coefficient. For a certain value of the Soret effect coefficient, the stable thermal gradient promote double-diffusive convective motion.

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Sample Design in Korea Housing Survey (주거 실태 및 수요조사 표본설계)

  • Byun, Jong-Seok;Choi, Jae-Hyuk
    • Survey Research
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    • v.11 no.1
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    • pp.123-144
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    • 2010
  • In new sample design for Korea Housing Survey to research about housing policy, total strata are forty five because individual results of sixteen regions are estimated. The sample size is determined by sample errors of several variables which are the living area, family income, householder income, and living expenses. The sample size of each region is determined by relative standard error of existing result, and the strata sample size is to use the square root proportion allocation. Enumeration districts are sampled by the probability proportion to size systematic sampling in proportion to the enumeration district size, and the systemic sampling to use assortment characteristics. We considered a new apartment complex because of variation reflections which are rebuilder and redevelopment of houses. To get estimators of mean and variance, we used the design weighting, non-response adjusting, and post-stratification. In order to consider estimation efficiency, we calculate the design effect using estimators of variance.

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Studies on the Physiological Chemistry of Dormancy and Germination in Panax. ginseng Seeds 2. Changes in Abscisic acid content during Stratification of Seeds. (인삼종자의 휴비 및 발아에 대한 생리화학적 연구)

  • 최선영;이강수
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.32 no.3
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    • pp.277-286
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    • 1987
  • Abscisic acid (ABA) content of the seed and endocarp during stratification were analyzed and then examined in relation to the embryo growth and germination. In mature red fruitlet, the ABA content was remarkably higher in sarcocarp than those in both seed ans endocarp. During the stratification before dehiscence, ABA content was gradually decreased in both seed and endocarp. After 90 days(dehiscent percentage; 96%) it came to 90 pmol/ g DW(69% decrease) and to 41 pmol/ g DW (80% decrease) in seed and in endocarp, respectively. The ratio of free from to total ABA content showed constant decrease in seed, but remained at higher level in endocap than in seed. Correlation between the decrease of ABA content and embryo growth showed higher significance in seed than in endocarp. During the stratification after dehiscence, ABA content in seed was gradually decreased at 4$^{\circ}C$ and 15$^{\circ}C$, After 90 days it came to 28 pmol/ g DW (69% decrease) and to 46 pmol/ g DW (49% decrease) at 4$^{\circ}C$ and at 15$^{\circ}C$, respectively. The ratio of free form to total ABA content was gradually increased at 4$^{\circ}C$, but remained almost constant at 15$^{\circ}C$. Correlation between the decrease of ABA content and days to first germination showed positive singificance only at 4$^{\circ}C$, whereas the correlation between the decrease and mean germination percentage per day showed negative significance at 4$^{\circ}C$, but positive significance at 15$^{\circ}C$. The above results indicate the ABA of the seed end endocarp during the stratification before dehiscence seems to be concerned with the immature embryo growth, but that of the seed during the stratification after dehiscence seems to show little effect on the germination capability(degree of breaking physiological dormancy).

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An Experimental Study on the Effect of Mixture Distribution in the Constant Volume Combustion Chamber on the Combustion Characteristics (정적 연소실내 혼합기 분포가 연소특성에 미치는 영향에 관한 실험적 연구)

  • 이기형;이창희;안용흠
    • Transactions of the Korean Society of Automotive Engineers
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    • v.12 no.3
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    • pp.10-18
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    • 2004
  • It is well known that the stratified charge combustion has many kind of advantages to combustion characteristics, such as higher thermal efficiency and less CO, NOx levels than conventional homogeneous mixture combustion. Although this combustion can be caused low fuel consumption, it is produced the high unburned hydrocarbon and soot levels because of different equivalence ratio in the combustion chamber. Moreover it has a lot of possibility of low output and misfire if the mixture gas would not be in existence around the spark plug. In this paper, fundamental studies for stratified combustion were carried out using a constant volume combustion chamber. The effect of locally mixture gas distribution according to control the direct injection and premixed injection in the chamber were examined experimentally. In addition, the effects of turbulence on stratified charge combustion process were observed by schlieren photography.