• 제목/요약/키워드: warm up period

검색결과 73건 처리시간 0.026초

Analysis of Effects on SWAT Estimation of Warm-Up Period

  • Lee, Ji-Won;Moon, Jong-Pil;Woo, Won-Hee;Kum, Dong-Hyuk;Kim, Ki-Sung;Lim, Kyoung-Jae
    • 한국수자원학회:학술대회논문집
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    • 한국수자원학회 2011년도 학술발표회
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    • pp.260-260
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    • 2011
  • SWAT is semi-distributed and continuous-time distributed simulation watershed model, which can simulate point and nonpoint source pollutants as well as hydrology and water quality. It was developed to predict the effects of alternative management decisions on water, sediment, and chemical yields with reasonable accuracy. It is able to predict and manage hydrology, sediments, nutrients, and pesticides with Best Management Practices (BMPs) in a watershed. SWAT model also has potential for use in ungauged basins to predict streamflow and baseflow from saturated source area in watersheds. According to various cultivation practices and climate change, SWAT model is available to analyze relative change in hydrology and water quality. In order to establish optimum management of water quality, both monitering and modeling have been conducted actively using SWAT model. As SWAT model is computer program to simulate a lot of natural phenomena, it has limitation to predict and reflect them with on hundred percent accuracy. Thus, it is possible to analyze the effect of BMPs in the watershed where users want to simulate hydrology and water quality only if model accuracy and applicability are assessed first of all and the result of it is well for the study watershed. For assessment of SWAT applicability, most researchers have used $R^2$ and Nash and Sutcliffe Efficiency (NSE). $R^2$ and NSE are likely to show different results according to a warm up period and sometimes its results are very different. There have been hardly any studies of whether warm up period can affect simulation results in SWAT model. In this study, how warm up period has a effect on SWAT results was analyzed and a appropriate warm up period was suggested. Lots of SWAT results were compared after using measured data of Soyanggang-dam watershed and applying various warm up period (0 ~ 10 year(s)). As a result of this study, when there was no warm up period, $R^2$ and NSE were 0.645, 0.602 respectively, when warm up period was 2 years, $R^2$ and NSE were 0.648, 0.632, and when warm up period was 4 years, $R^2$ and NSE were 0.663, 0.652 separately. Through this study, sensitive analysis of warm up period in SWAT model was conducted, and this study could give a guideline able to simulate hydrology and water quality for more accuracy than before as users change a lot of warm up periods as well as any simulation parameters.

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흡기밸브에서의 연료증발이 혼합기 형성에 미치는 영향 (The effect of fuel evaporation in the intake valve back on mixture preparation)

  • 박승현;이종화;유재석;신영기;박경석
    • 한국자동차공학회논문집
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    • 제7권8호
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    • pp.107-115
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    • 1999
  • Hydrocarbon emission from spark ignition engines deeply relates with fuel evaporation mechanism. Therefore, fuel evaporation on the back of the intake valve is very important to understand fuel evaporation mechanism during engine warm up period. Intake valve heat transfer model was build up to estimate the amount of fuel evaporation on the intake valve back . Intake valve temperature was measured intake valve temperature is increased rapidly during few seconds right after engine start up and it takes an important role on fuel evaporation. The liquid fuel evaporation rate on the intake valve back proportionally increases as valve temperature increases, however its contribution slightly decreases as intake port wall temperature increases. The fuel evaporation rate on the valve back is about 40∼60% during engine warm-up period and it becomes about 20∼30% as intake port wall temperature increases. The estimation model also makes possible model also makes possible to review the effect of valve design parameters such as the valve mass and seat area on fuel evaporation rate through intake valve heat transfer.

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"온열경위(溫熱經緯)" 중(中) 섭향암(葉香巖)의 삼시복기외감(三時伏氣外感)에 관한 연구(硏究) (A Study on Latent-gi by Yexiangyan "Wenrejingwei")

  • 안준모;송지청;정현종;금경수
    • 대한한의정보학회지
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    • 제16권2호
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    • pp.163-187
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    • 2010
  • The concept of latent-gi(伏氣) was first mentioned in Yellow Emperor's Canon of Internal Medicine. For example, Elementary Questions states, "Damage by cold in winter necessarily engenders warm disease in the spring." Zhang Zhong-Jing of Han Dynasty in On Cold Damage and Miscellaneous Diseases mentions warm disease, stating, for example, "Greater yang disease with heat effusion and cough and without aversion to cold is warm disease. If sweating is applied, and there is generalized heat, this is wind warmth." However, the concept of warm disease was not central to his systematic presentation of externally contracted disease which placed the emphasis on wind and cold as the major causes of these diseases. Zhang Zhong-Jing's theories centuries after in the Sung Dynasty were to become the focus of the cold damage school, whereas the concept of warm disease was to become the focus of a rival school, the warm disease school. In the Sui-Tang Period, The Origin and Indications of Disease mentions warm diseases, their causes, patterns, and major principles of treatment. Successive generations of doctors wrote about warm disease, and in the Ming Dynasty writings on the subject become more prolific. This development is attributable on the one hand to the opening up of the south of China where febrile diseases tended to be of a different nature than in the north, and on the other to pestilences arising as a result of wars. In this period, Wu You-Xing in On Warm Epidemics explained in detail the laws governing the origin, development and pattern identification of warm epidemics. Notably, he posed the etiological notion of a contagious perverse gi.

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전기밥솥에서 보온중인 밥의 조직감 변화 (Textural Changes of Cooked-Rice during Warm Keeping in Electrical Rice Cooker)

  • 이영진;황선옥;김상권;박윤서;전재근
    • Applied Biological Chemistry
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    • 제38권5호
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    • pp.422-424
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    • 1995
  • 밥의 보온저장중 조직감변화를 조사하기 위하여 밥솥의 보온 온도를 $73^{\circ}C$ 로하여 42시간동안 저장하였다. 보온 기간중 경시적으로 밥을 채취하여 원통형 블록으로 시료를 만든 후 경도와 점착성을 측정하였다. 보온 초기에는 밥의 경도는 1.61kg이었으며 12시간 후에는 1.95kg까지 증가하였다. 그 이후 3시간 이내에 1.57kg으로 감소한 후 서서히 감소하여 42시간에는 1.44kg에 이르렀다. 밥의 점착성은 0.51kg에서 0.32kg로 서서히 감소하였으며 탄력성과 씹힘성은 경도의 양상과 유사하게 변화하였다. 한편 응집성은 뚜렷한 변화를 보이지 않았다.

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A Pilot Study on the Heart Rates of Jeju Horses during Race Trials

  • Seung-Ho Ryu;HeeEun Song;Eliot Forbes;Byung-Sun Kim;Joon-Gyu Kim;Ki-Jeong Na
    • 한국임상수의학회지
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    • 제40권6호
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    • pp.464-467
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    • 2023
  • The autonomic regulation of heart rate (HR) is an indicator of the body's ability to adapt to an exercise stimulus. However, there are no reports on this topic in relation to Jeju horses used for racing. The aim of this study was to analyze the HR responses of Jeju horses during race trials and to investigate the correlation between HR and performance in these horses. HR data were collected from 17 healthy 2- to 7-year-old Jeju horses wearing HR monitors during race trials. Pearson correlation coefficients was used to determine the significance of the association between the race trial time and HR. A significant inverse correlation was observed between the race trial time (performance) and both the maximal HR (HRmax, r = -0.69, p < 0.01) and HR reserve (HRR) (HRmax - average HR during the warm-up period, r = -0.63, p < 0.01) and between the HRR and HRmax (r = 0.73, p < 0.01). Horses with a lower average HR during the warm-up period and higher heart rates during the trial achieved faster race trial times. This study reports the first HR measurements in Jeju horses during race trials, providing new insights into the HR response of this breed to exercise. The use of a noninvasive remote HR monitor system allowed assessment of exercise responses in the field, and the results suggest that both the HRR during warm-up period and HRmax may be useful performance indicators in Jeju horses.

농업용수의 수온 상승에 관한 연구

  • 황은;김철규;이상범
    • 물과 미래
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    • 제5권2호
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    • pp.17-29
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    • 1972
  • The persent study aims at finding out a means of prevention cool spell damages on the hilly areas. The irrigation plots of 24 hour stored water warm water way and warm water plots, cool water way are respectively established to find out water temperature and influnce on the growing rice plants. The results obtained are summed up as follows. 1. Warm water areas consisted of $5 m^2 Q=0.93 1{\ell}/sec$, V=31 cm/sec, S=1/1, 000, L=81.6m, B=5cm, h=6cm, t=4min 33sec, drops=9 areas, are constructed to help the water temperature of $14.5^{\circ}C$ rise to that of $21.6^{\circ}C$. This indicates lower temperature than $23^{\circ}C$ of critical water temperature in irrigation facilities by $1.45^{\circ}C$ and than $26.2^{\circ}C$ of balanced water temperature of Seoul arears by $4.6^{\circ}C$. But this does not give much influance on rice plant cultivation. 2. The rising of water temperature is influened according to the temperature, solar radiation but the water temperature changes according to the heat absorption of organized materials, weather and terraces. The difference of water temperature could be found in the first growing stage. 3. Through the warm water way of water rises to the temperature of $21.6^{\circ}C$ which also rises to the temperature of around $30^{\circ}C$ in the paddy field of submerged irrigation. The rice plants are comparatively free from prolonged cool damage, reproduction abstructive damage. 4. The water temperature in rice field in proportion to temperature influence of weather condition but the water temperature approaches to that of weather in the days of later growing stage and water temperature become lower than the air temperature in the fruit stage. 5. The water in the submreged field is $10^{\circ}C$ warmer than in the warm water way during the first growing stage period but the water temperature in the warm water way is warmer in the later growing stage period. The cool water of $14.5^{\circ}C$ is warmed to $30.1^{\circ}C$ and rice plants cultivation is free from other damages. 6. The 12% increased production or 570.98kg/10a is made cool water plot by rising the temperature of water from $14.5^{\circ}C$ to $21.6^{\circ}C$ making the water run through warm water way. 7. The damage inflicted by the cool water irrigation during the first growing stage period is the obstruction of peak tillering stage and the obstruction of heading the later growing stage period and the obstruction of fruiting and number of panides per fill.

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가솔린엔진의 연료 미립화 향상을 위한 공급연료 가열에 대한 실험적 연구 (An Experimental Study on the Fuel Heating for Enhancing Fuel Atomization)

  • 윤팔주;박승범;선우명호;천동필
    • 한국자동차공학회논문집
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    • 제9권4호
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    • pp.112-120
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    • 2001
  • Poor fuel vaporization in gasoline engines causes the problem of HC emission during the cold start and warm-up period. This paper presents a strategy to improve fuel atomization during the warm-up phase. In this experiment, the heated fuel-rail system is constructed to investigate the effects of fuel heating on the average size of fuel droplets. The fuel atomization effects are examined by measuring Sauter Mean Diameter (SMD) of the fuel droplets from the three different types (two-hole, pintle, and six-hole) of injectors based upon a returnless heated fuel-rail system. The results show that the six-hole type injector is the most sensitive to fuel heating in terms of SMD among three different types of injectors.

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이중관 배기메니폴드의 HC저감효과 및 열특성에 관한 연구 (A Study on the Reduction of HC and Heat Characteristics of the Dual Pipe Exhaust Manifold)

  • 박경석;허형석
    • 한국자동차공학회논문집
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    • 제9권6호
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    • pp.103-111
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    • 2001
  • During cold-start period, the reduction of exhaust emissions is a challenging task. To decrease harmful gaseous substances such as HC, it is necessary to realize a fast catalyst warm-up. In this study, the performance of dual pipe exhaust system have been carried out through different test mode. From measurement of gas temperature and HC concentration, the following conclusions were derived ; 1) Compared with single pipe, dual pipe exhaust system remarkably increase temperature of exhaust gas going through M.C.C(Main Catalytic Converter). 2) W.C.C.(Warm-up Catalytic Converter) also decreases HC emission. To reduce HC emission, it is helpful to use W.C.C. as well as dual pipe exhaust system. 3) Using finite element method, it is shown that inner parts have much higher distribution of temperature than outer parts.

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CHANGE OF CATALYST TEMPERATURE WITH UEGI TECHNOLOGY DURING COLD START

  • CHO Y.-S.;KIM D.-S.
    • International Journal of Automotive Technology
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    • 제6권5호
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    • pp.445-451
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    • 2005
  • Most of the pollutants from passenger cars are emitted during the cold-transient phase of the FTP-75 test. In order to reduce the exhaust emissions during the cold-transient period, it is essential to warm up the catalyst as fast as possible after the engine starts, and the Unburned Exhaust Gas Ignition (UEGI) technology was developed through our previous studies to help close-coupled catalytic converters (CCC) reach the light-off temperature within a few seconds after cold-start. The UEGI system operates by igniting the unburned exhaust mixture by glow plugs installed upstream of the catalyst. The flame generates a high amount of heat, and if the heat is concentrated on a specific area of monolith surface, then thermal crack or failure of the monolith could occur. Therefore, it is very important to monitor the temperature distribution in the CCC during the UEGI operation, so the local temperatures in the monolith were measured using thermocouples. Experimental results showed that the temperature of CCC rises faster with the UEGI technology, and the CCC reaches the light-off temperature earlier than the baseline case. Under the conditions tested, the light-off time of the baseline case was 62 seconds, compared with 33 seconds for the UEGI case. The peak temperature is well under the thermal melting condition, and temperature distribution is not so severe as to consider thermal stress. It is noted that the UEGI technology is an effective method to warm up the catalyst with a small amount of thermal stress during the cold start period.

신량해표(辛凉解表)의 역사와 의미에 대한 고찰 (A Study on the History and Meaning of Exterior Relief Methods using Pungent-cool Properties)

  • 윤기령;백유상;장우창;정창현
    • 대한한의학원전학회지
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    • 제33권1호
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    • pp.149-158
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    • 2020
  • Objectives : This study aims to examine the exterior relief method through pungent-cool properties in comparison to pungent-warm properties historically, to understand the meaning of 'exterior relief through pungent-cool' more thoroughly. Methods : Contents mentioning the treatment method directly were examined historically, then analyzed. Results & Conclusions : The method to relieve the exterior through pungent-cool properties has developed by overcoming the limitations of the method to relieve the exterior through pungent-warm properties since it was first established in 『Shanghanzabinglun』(『傷寒雜病論』). The term 'relief of the exterior through pungent-coolness'(辛凉解表) was first mentioned in the Ming period, referring to weak level of perspiration. Yetianshi(葉天士) explained it as communicating Weiqi(衛氣) using pungent-cool medicinals for heat to discharge through the exterior, resulting in mild sweating. In 『Wenbingtiaobian』(『溫病條辨』) the term 'to relieve the flesh'(解肌) refers to both mild sweating through pungent-warm medicinals and the opening of the exterior through pungent-cool medicinals for pathogenic qi to exit, resulting in sweating. If the exterior relief of the pungent-warm medicinals happens through the warm Yang qi(陽氣) stimulated the inner Yin fluids(陰液) to discharge as sweat, that through pungent-cool medicinals relieves stagnation in the exterior, opening up a way for the pathogenic heat to exit. From the perspective of the main therapeutic mechanism for pungent-cool medicinals to be its coolness relieving heat, the term 'exterior relief through pungent-coolness' becomes erroneous. For the 'exterior relief through pungent-coolness' category to be valid, the meaning of 'exterior relief' needs to be expanded to include not only stimulated sweating but the treatment process that could result in sweating.