• 제목/요약/키워드: rate effects

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질소희석과 압력이 석탄가스 비예혼합 화염구조와 소염 스칼라 소산율에 미치는 영향 해석 (Effects of Fuel-Side dilution and Pressure on Structure and Extinction Scalar Dissipation Rate of Syngas Nonpremixed Flames)

  • 박상운;신영준;김용모
    • 한국연소학회:학술대회논문집
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    • 한국연소학회 2012년도 제45회 KOSCO SYMPOSIUM 초록집
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    • pp.61-62
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    • 2012
  • The present study has numerically investigated the effects of fuel-side dilution and pressure on flame structure and extinction scalar dissipation rate of turbulent syngas nonpremixedd flames. Numerical results indicate that for highly diluted case, peak temperature is decreased and stoichiometric mixture fraction is increased. By decreasing the pressure and the nitrgen dilution levelcreased, the extinction scalar dissipation rate is increased.

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정압기지에 대한 산불화재 영향평가 (Effect Evaluation of Forest Fire on Governor Station)

  • 장서일;차순철;강경식
    • 대한안전경영과학회지
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    • 제9권2호
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    • pp.49-57
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    • 2007
  • This Study is to suggest a method of effect evaluation of forest fire on governor station in shrub land. Theoretically, to evaluate effects of forest fire, it is combined that Spread Rate of Forest Fire, Flame Model, and Thermal Radiation Effects Model; i.e. a travel time of forest fire is calculated by Spread Rate of Forest Fire, fire-line intensity is calculated by Flame Model, and effects of fire-line intensity is affected by Thermal Radiation Effects Model. With the aforementioned method, we could carry out the effect evaluation of forest fire on governor station in shrub land and could distinguish scenarios to need protection plan from all scenarios.

Effects of a Non-absorbable Gas on the Absorption Process in a Vertical Tube Absorber

  • Hur, ki-Joon;Jeong, Eun-Soo;Jeong, Si-Young
    • International Journal of Air-Conditioning and Refrigeration
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    • 제7권
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    • pp.69-78
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    • 1999
  • Effects of a non-absorbable gas on the absorption process in a vertical tube absorber has been investigated numerically. The water vapor mixed with air is absorbed into LiBr/water solution film. The flow is assumed to be laminar and fully developed in both liquid and gas phases. The diffusion and energy equations were solved in both phases to give the temperature and concentrations, from which heat and mass fluxes were determined. The local absorption rate has been shown to decrease as the mass fraction of air in the water vapor increases. The vapor pressure of water at the liquid-vapor is interface reduced significantly since the non-absorbable gas accumulates near the interface. The effects of non-absorbable gases on absorption rate become larger as the mass flow rate of the vapor decreases. For a small amount of non-absorbable gases, the total absorption rate of water vapor increases as the mass flow rate of the vapor decreases. The total absorption rate increases as the mass flow rate of the vapor increases for large concentrations of non-absorbable gases at the inlet of an absorber.

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동태적 패널모형을 통한 무역보험의 거시경제효과 연구 (A Study on the Macroeconomic Effects of Trade Insurance Using Dynamic Panel Models)

  • 남상욱
    • 무역상무연구
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    • 제61권
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    • pp.165-190
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    • 2014
  • The purpose of this study is to measure the trade insurance's macroeconomic effects by analyzing the causality between major economic variables(GDP per capita, market interest rate, inflation, unemployment rate, exchange rate) and trade insurance variable. I conducted empirical analyses using First-difference GMM(Generalized Method of Moments), System GMM and Panel-VAR Model, with panel data from 11 countries(Korea, United States, Japan, BRICs, Indonesia, Singapore, Hong Kong, Vietnam) between 1992 and 2011. There are several important findings. Above all, Trade insurance is positively and significantly related to GDP. This results show that trade insurance serves to increase economic growth. In other words, trade insurance leads to economic growth by helping increase GDP per capita. Especially, trade insurance negatively related to unemployment rate, it is for sure that trade insurance contribute to decrease unemployment rate. And trade insurance helps control of inflation. It is also confirmed that trade insurance contributes to price stability, which in turn serves to stabilize the overall economy. And this research finds as uncertainty in the market increases, seen it as increase of exchange rate, increasing trade insurance supply is stabilize the exchange rate.

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Symmetric and Asymmetric Effects of Financial Innovation and FDI on Exchange Rate Volatility: Evidence from South Asian Countries

  • QAMRUZZAMAN, Md.;MEHTA, Ahmed Muneeb;KHALID, Rimsha;SERFRAZ, Ayesha;SALEEM, Hina
    • The Journal of Asian Finance, Economics and Business
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    • 제8권1호
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    • pp.23-36
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    • 2021
  • The study explores the nexus between foreign direct investment (FDI), financial innovation, and exchange rate volatility in selected South Asian countries for 1980 to 2017. The study applies the unit root test, Autoregressive Distributed Lagged, nonlinear ARDL, and causality test following Toda-Yamamoto. Unit root tests ascertain that variables are integrated in a mixed order; few variables are stationary at a level and few after the first difference. Empirical model estimation with ARDL, Long-run cointegration revealed with the tests of FPSS, WPSS, and tBDM by rejecting the null hypothesis of "no cointegration." This finding suggests that, in the long-run financial innovation, FDI inflows, and exchange rate volatility move together. Moreover, study findings established adverse effects running from FDI inflows and financial innovation to exchange rate volatility in the long run. These findings suggest that continual FDI inflows and innovativeness in the financial system assist in lessening the volatility in the foreign exchange market. Furthermore, nonlinear ARDL confirms the presence of asymmetric cointegration in the model. The standard Wald test established asymmetric effects running from FDI inflows and financial innovation to exchange rate volatility, both in the long and short run. Directional causality unveils feedback hypothesis holds for explaining causality between FDI, financial innovation, and exchange rate volatility.

HCCI 수소기관에서 운전영역확장을 위한 EGR 효과 분석 (An Analysis on the Effects of EGR to Extend Operation Region for a HCCI Hydrogen Engine)

  • 이건식;김진구;변창희;이종태
    • 한국수소및신에너지학회논문집
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    • 제26권6호
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    • pp.560-566
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    • 2015
  • HCCI (Homogeneous Charge Compression Ignition) hydrogen engine has relatively narrower operation range caused by knock occurrence due to the rapid pressure rising by using higher compression ratio. In this study, EGR as one of the countermeasure methods is considered to extend operation range of HCCI hydrogen engine. Also, the effects of hydrogen EGR are compared with the effects of EGR using hydrocarbon fuel. Hydrocarbon EGR is carried out by adding carbon dioxide to exhaust gas of HCCI hydrogen engine. As the results, EGR has positive effects on a HCCI hydrogen engine in reducing rate of pressure rise as same as the other engines used hydrocarbon fuels. However, the effects of hydrogen EGR are better than those of hydrocarbon EGR in decreasing minimum compression ratio and rate of pressure rise. When applying EGR to HCCI hydrogen engine by 20% rate, the rate of pressure rise decreases by 58% and it results in about 48% increase of the operation range in terms of supply energy.

소 초기배의 단순배양액에서의 체외발생 및 개선효과 (In Vitro Development and the Improving Effects of Bovine Embryos in Simple Media)

  • 이홍준;서승운;이상호;송해범
    • 한국수정란이식학회지
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    • 제10권3호
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    • pp.251-256
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    • 1995
  • This study was experimented that developmental effects of bovine in vitro fertilized embryos by coculture system and supplementation of energy materials into simple media. With the ovaries from slaughter house in vitro maturation by 24h, in vitro fertilization was performed with sperms collected by Percoll gradient method. Fertilized embryos were cocultured in 15% FCS+CZB medium with BOEC(bovine oviductal epithelial cell), GCM (granulosa cell monolayer) and MEFC(mouse embryonic fihrohlast cell). And also in this study, there was trying to improve the early developmental rate of embryos by addition of concentration-controlled Na-pyruvate, D-glucose which were used as energy sources into CZB medium. In vitro developmental rate was confirmed by the cleavage rate of 48h post-IVF and the embryo development rate at 240h culture. In the coculture system BOEC had 20.0% of blastocysts rate, which was higher than that of other coculture systems. To determine the optimum concentration for early embryo developmental rate rapidly, through the gradient of concentrations of Na-pyruvate and D-glucose, we focused on the cleavage rate at 48h and blastocysts rate at 240h. In case of Na-pyruvate, cleavage rate and developmental rate over 3-cell were lower at the concentration of 1.OOrnM than the other treatment concentrations, otherwise the blastocysts rate was higher as 23.2% than the others. That result showed that as like reported group which had higher develop-mental rate over 3-cell was also higher to the blastocysts rate. In case of D-glucose, there was no effects through the concentration changes. It was the result of this study for which the use of BOEC coculture system and 1.OOmM Na-pyruvate as an energy source had an effect upon embryo development.

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근로자의 건강영향인지와 사망만인율을 통한 직무스트레스 해소계수 산정 - 제조업 현장근로자를 중심으로 - (Estimation of Job Stress Relieve Coefficient through Recognizing Health Effects of Workers and Death Rate per 10,000 workers - A manufacturing worker -)

  • 한만형;천영우;이익모;황용우
    • 한국산업보건학회지
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    • 제29권1호
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    • pp.69-81
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    • 2019
  • Objective: The purpose of this study was to find out what kind of change in death rate when job stress is solved by calculating job stress relieve coefficient. Methods: This study used the data of the fourth working condition survey. Regression analysis was used to determine the relationship between health effects recognition and Death rate per 10,000 workers. After that the recognizing and non - recognizing groups were categorized by health effects recognition, and the differences between the two groups were confirmed by cross tabulation analysis. Results: Regress analysis P-value is 0.011 and $R^2$ is 0.979. Death rate per 10,000 worker increased with the increase in the number of non - health impact recognizing group. The relieve factors were (1) work culture(2.859) (2) physical environment(2.184), (3) improper reward (1,839), (4) relationship conflict(1.646), (5) job requirement(1.613), (6) job autonomy(1.354), (7) job instability(1.334), And (8) organizational system(1.201). The higher the relieve coefficient is, the higher the probability of belonging to the non - health impact recognizing group when there is no job stress factor. Conclusions: When job stress is resolved, there is a high probability that the health impact recognition is reduced, which can lead to an increase in death rate. but according to previous studies, Job stress can cause accidents by reducing the safety behavior of accidents. The job stress management plan should simultaneously consider reducing job stress and increasing health impact recognition.

Ketamine으로 마취된 견에 있어서 Doxapram의 회복효과 (Effects of Doxapram on Ketamine Anesthesia in Dogs)

  • 김명철
    • 한국임상수의학회지
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    • 제8권2호
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    • pp.171-175
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    • 1991
  • This study was carried out to evaluate the effects of doxapram after ketamine treatment. Twelve healthy dogs were anesthetized with ketamine(15mg/kg IM) and then twenty minutes after the injection of ketamine six dogs received doxapram(2mg/kg IV)and six dogs received saline(5$m\ell$ IV)as a control group. Recovery time, respiratory rate, heart rate and electrocardiogram findings(ECG)were recorded. Recovery time was significantly decreased(p<0.05)by doxapram. Respiratory rate showed a maximal increase immediately after the administration of doxapram. Thereafter respiratory rate gradually decreased and revealed normal levels 10 minutes after the injection of doxapram. Ketamine increased significantly (p<0.05) heart rate. Heart rate showed slight increase immediately after the administration of doxapram. Thereafter heart rate gradually decreased, and revealed normal levels 20 minutes after the injection of doxapram.

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횡충돌 하중을 받는 비보강 강판의 구조거동에 대한 크기 효과 (Scale Effects on the Structural Behavior of Steel Unstiffened Plates Subjected to Lateral Collisions)

  • 조상래;박정열;송승욱;박상현
    • 대한조선학회논문집
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    • 제55권2호
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    • pp.178-186
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    • 2018
  • The scale effects on the permanent deformations and fractures of structures subjected to impact loadings have been aware by structural engineers for a long time. Experimental investigations have been performed with various structures to demonstrate the effects, but very few are directly related with marine structural elements. Furthermore, the causes of the scale effects have not clearly been answered yet. In this study, to quantify the scale effects on the permanent deflections, lateral collision tests were performed on steel unstiffened plates and the numerical analyses of the tested models were also conducted using a commercial package, Abaqus. After the substantiation of the numerical tool using the test results, a parametric study was carried out considering and neglecting the strain-rate hardening. Based upon the parametric study results, it may be concluded that the main cause of the scale effects on the permanent deflections of steel unstiffened plates subjected to lateral collision loads is the strain-rate effects.