• Title/Summary/Keyword: Temperature controlling effect

Search Result 277, Processing Time 0.03 seconds

A Study on the Temperature Variation Rate and Temperature Controlling Effect of Parks and Rivers in a City (도시 내 공원과 하천의 기온변화율과 기온완화효과에 관한 연구)

  • Lee, Kang-Guk;Kim, Tae-Woo;Seo, Won-Duck;Hong, Won-Hwa
    • KIEAE Journal
    • /
    • v.11 no.3
    • /
    • pp.3-9
    • /
    • 2011
  • For urban development, natural covering area such as urban green or river is more rapidly reducing than artificial surface covering area like concrete or asphalt, so thermal environment in a city is being drastically deteriorated. Recently, since people recognize the importance of parks or rivers in a city which play roles as an environmental buffer in it, many studies and policies consider how to improve the life quality of citizens and urban environment. This study aims to examine the status of thermal environment variation in the parks and rivers of the city which is the subject of this research and provide foundational data for urban environment plans through research on temperature variation rate and temperature controlling effect.

The experimental study of post injection effect on exhaust gas temperature and composition in a common rail DI diesel engine (커먼레일 디젤엔진에서 후분사 변화가 배출가스 성분 및 온도 변화에 미치는 영향에 대한 실험적 연구)

  • Chung, Jae-Wook;Chang, Dong-Hoon;Park, Jung-Kyu;Chun, Kwang-Min
    • Journal of ILASS-Korea
    • /
    • v.9 no.1
    • /
    • pp.15-20
    • /
    • 2004
  • The post injection effect to enhance aftertreatment devices' performance is essential to meet future stringent emission standards by controlling exhaust gas temperature and emission pollutants. The test has been made with commercial common rail diesel engine by post injection manipulation, to optimize exhaust gas temperature while guarantee low fuel penalty. The optimization was done at 1500, 2000 and 2500[rpm] for 2, 4[bar] condition which show low exhaust gas temperature. The main purpose of this test is dedicated to understand mechanism of exhaust gas temperature rise while optimizing

  • PDF

Changes in the Attributable Burden of High Temperatures on Deaths (하절기 기온상승으로 인한 사망의 기여부담 변화)

  • Ha, Jongsik
    • Journal of Environmental Health Sciences
    • /
    • v.38 no.6
    • /
    • pp.460-471
    • /
    • 2012
  • Objectives: Due to global warming resulting from climate change, there has been increasing interest in the relationship between temperature and mortality. These temperature-related deaths depend on diverse conditions related to a given place and person, as well as on time. This study examined changes in the impact of high temperatures on death in summer, using the effect and burden of elevated temperatures on deaths in Seoul and Daegu. Methods: A Poisson regression model was used to estimate short-term temperature effects on mortality. Temperature-related risks were divided into three time periods of equal length (1996-2000, 2001-2005, and 2006-2010). In addition, in order to compare the impact of high temperatures on deaths, this study calculated the proportion of attributable deaths to population, which simultaneously considers the threshold and the slope above the threshold. Results: The effect and burden of high temperatures on deaths is high in Daegu. However, the impact (i.e. the effect and burden) of elevated summer temperatures on deaths has declined over the past 15 years. Sensitivity analyses using alternative thresholds show the robustness of these findings. Conclusion: This study suggests that the attributable burden of high temperatures on deaths to be more plausible than relative risk or threshold for comparing the health impact of high temperatures across populations. Moreover, these results contain important implications for the development or the adjustment of present and future strategies and policies for controlling the temperature-related health burden on populations.

Additional Effect of Zeolite Based on Bactericidal Activated Carbon Spheres with Enhanced Adsorption Effect and Higher Ignition Temperature

  • Zhu, Lei;Ye, Shu;Asghar, Ali;Bang, Seong-Ho;Oh, Won-Chun
    • Journal of the Korean Ceramic Society
    • /
    • v.53 no.1
    • /
    • pp.68-74
    • /
    • 2016
  • In this study, the fabrication of zeolite combined activated carbon spherical samples was carried out as follows. Briefly, ZSM-5 zeolite and activated carbon were composed as main absorbent materials; by controlling the weight percentage of zeolite and binder materials, a series of spherical samples (AZP 4, 6, 8) were prepared. These spherical samples were characterized by BET, XRD, SEM, EDX, and pressure drop; benzene and iodine adsorption tests, bactericidal effect test, and ignition temperature test were also performed. The adsorption capability was found to depend on the BET surface area; the spherical samples AZP6 with high BET surface area of $1011m^2/g$ not only exhibited excellent removal effects for benzene (24.9%) and iodine (920mg/g) but also a good bactericidal effect. The enhanced ignition temperature may be attributed to the homogeneous dispersion conditions and the proper weight percentage ratio between zeolite and activated carbon.

Study on the Characteristics of Piston Friction Losses for Fuel Injected Mass and Oil Temperature in a Gasoline Engine (가솔린 엔진에서 연료 분사량 및 오일 온도에 따른 피스톤 마찰손실 특성 연구)

  • Kang, Jongdae;Cho, Jinwoo;Park, Sungwook
    • Journal of ILASS-Korea
    • /
    • v.27 no.3
    • /
    • pp.161-166
    • /
    • 2022
  • To measure the change in friction loss due to the control of fuel mass and oil temperature in a gasoline engine, the floating liner method was used to measure the friction generated by the piston of a single-cylinder engine. First, to check the effect of combustion pressure on friction, the friction loss was measured by adjusting the fuel mass. It was confirmed that the friction loss increased as the fuel mass increased under the same lubrication conditions. In addition, it was confirmed that the mechanical efficiency decreased as the fuel mass increased. Next, to check the effect of lubrication conditions on friction, the friction loss was measured by controlling the oil temperature. It was confirmed that friction loss increased as the oil temperature decreased at the same fuel mass. As the oil temperature decreases, the viscosity increases, resulting in decreased mechanical efficiency and increased friction loss.

Effect of Temperature Gradient on the Defects of Nd;YAG Single Crystal Grown by Czochralski Method (융액인상법에 의한 Nd;YAG 단결정 성장시 온도구배의 변화에 따른 결함거동)

  • 김한태;배소익;이상호;정수진
    • Journal of the Korean Ceramic Society
    • /
    • v.34 no.10
    • /
    • pp.1015-1020
    • /
    • 1997
  • In the Nd;YAG crystal growth by Czochralski method, the relationship between the core formation and the solid-liquid interface was observed by controlling the temperature gradient in the furnace. When the crystal was grown along<111> direction, defects and core area were reduced as the temperature gradient increased. The optimum temperature gradient was found to be higher than 4$0^{\circ}C$/cm. The Nd3+ concentration analysis by ICP-Mass showed that the segregation coefficient was about 20% higher in the core region than core-free region, where the segregation coefficients of core region and core-free region were 0.22 and 0.18, respectively.

  • PDF

An Experimental Study on the Characteristics of Metal Temperature and Heat Rejection to Coolant of Gasoline Engine (가솔린엔진의 금속면온도 및 냉각수로의 전열 특성에 관한 실험적 연구)

  • 오창석;유택용;신승용;최재권
    • Transactions of the Korean Society of Automotive Engineers
    • /
    • v.9 no.3
    • /
    • pp.35-41
    • /
    • 2001
  • In recent applications, map controlled thermostat has been adapted to optimize engine cooling system and vehicle cooling system. First of all, this strategy is focused on improving fuel consumption rate and reducing emissions, especially unburned hydrocarbon. The object can be obtained through controlling engine metal temperature by varying engine coolant temperature with engine load and speed. To achieve this goal, it is necessary to understand the characteristics of engine metal temperature and heat rejection rate to coolant. From the results of tested engines, it is obvious that fuel consumption rate has more dominant effect on engine metal temperatures than the corresponding engine power does. Also, Re-Nu relation which shows heat rejection rate to coolant in function of air-fuel mixture and engine specifications has been studied. Also, the empirical Re-Nu relation at full loaded engine was developed.

  • PDF

Effect of Various Partial Replacements of Cement with Blast Furnace Slag and Different Placing Times on Thermal Properties of Mass Concrete and Modeling Work (타설시간차에 의한 고로슬래그 미분말의 치환율별 매스콘크리트의 온도특성)

  • Kim, Jong
    • Journal of the Architectural Institute of Korea Structure & Construction
    • /
    • v.35 no.10
    • /
    • pp.207-215
    • /
    • 2019
  • The aim of the research is analyzing the simple adiabatic temperature rising properties and the heat of hydration based on different placing timing of the mass concrete depending on various replacing ratios of blast furnace slag to comparative analyze the thermal cracking index and cracking possibility. As a result from the experiment, a suggested adiabatic temperature rising equation based on various blast furnace slag replacing ratios can be provide favorable correlation with over 0.99 of $R^2$ value by applying the initial induction period. With this relationship, more accurate prediction of the amount of the hydration heat rising and heating timing, and it is known that there is an approximately $13.1^{\circ}C$ of gap between plain concrete without blast furnace slag and concrete with 80 % of replacing blast furnace slag. To control the setting time and heat rising gap, the mix designs between top and bottom concrete casts were changed 15 cases, and D, E, H, I, and L models of controlling the heat of hydration showed 41.23 to $46.88^{\circ}C$ of core temperature and 0.98 to 1.27 of thermal cracking index. Therefore the cracking possibility was 15 to 52 % of favorable results of possibly controlling both the cracking due to the internal and external retainment and concrete temperature at early age.

A Study on Output Monitoring of Green Roof Integrated PV System through Surface Temperature Algorithm (표면온도 알고리즘을 통한 옥상녹화통합형 태양광시스템의 출력 모니터링 연구)

  • Kim, Tae-Han;Park, Sang-Yeon
    • KIEAE Journal
    • /
    • v.15 no.1
    • /
    • pp.89-95
    • /
    • 2015
  • The centralized power supply system and rainwater treatment system, which are major infrastructure in modern cities, are showing their limitations in accommodating environment load due to climate changes that has aggravated recently. As a result, complex issues such as shortage of reserve power and urban flooding have emerged. As a single solution, decentralized systems such as a model integrating photovoltaic system and rooftop greening system are suggested. When these two systems are integrated and applied together, the synergy effect is expected as the rooftop greening has an effect of preventing urban flooding by controlling peak outflow and also reduces ambient temperature and thus the surface temperature of solar cells is lowered and power generation efficiency is improved. This study aims to compare and analyze the monitoring results of four algorithms that define correlations between micro-climate variables around rooftop greening and the surface temperature of solar cells and generate their significance. By doing so, this study seeks to present an effective algorithm that can estimate the surface temperature of solar cell that has direct impact on the efficiency of photovoltaic power generation by observing climate variables.