• 제목/요약/키워드: intake process

검색결과 401건 처리시간 0.03초

가시화 엔진을 이용한 직분식 예혼합 압축착화 디젤엔진의 화염 및 연소특성 (Flame and Combustion Characteristics of D.I. HCCI Diesel Engine using a Visualization Engine)

  • 권오영;류재덕;이기형;이창식
    • 한국자동차공학회논문집
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    • 제10권6호
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    • pp.100-107
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    • 2002
  • Combustion characteristics of diesel engine depends on mixture formation process during Ignition delay and premixed flame region. Fuel and air mixture formation has a great influence on the exhaust emission. Therefore, the present study focused on the combustion mechanism of Homogeneous Charge Compression Ignition (HCCI) engine. This study was carried out to investigate the combustion characteristics of direct injection type HCCI engine using a visualization engine. To investigate the combustion characteristics, we measured cylinder pressure and calculated heat release rate. In addition, we investigated the flame development process by using visualization engine system. From the experimental result of HCCI engine, we observed that cool flame was always appeared in HCCI combustion and magnitude of cool flame was proportional to magnitude of hot flame. And we also found that fuel injection timing is more effective to increase lean homogeneous combustion performance than intake air temperature. Since increasing the intake air temperature improved fuel vaporization before the fuel atomizes, we concluded that increasing the temperature has disadvantage fur homogeneous premixed combustion.

Which CDM methodology is the best option? A case study of CDM business on S-Water treatment plant

  • Kyung, Daeseung;Lee, Woojin
    • Advances in environmental research
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    • 제1권2호
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    • pp.125-142
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    • 2012
  • Clean development mechanism (CDM) validity study was conducted to suggest better and more adaptable CDM scenario on water treatment plant (WTP). Potential four scenarios for CDM project; improvement of intake pumping efficiency, hydro power plant construction, solar panel construction and system optimization of mechanical mixing process were evaluated on S-WTP in Korea. Net present value (NPV) of each scenario was estimated based on sensitivity analysis with the variable factors to investigate the CDM validity percentile. Hydro power plant construction was the best option for CDM business with 97.76% validity and $1,127,069 mean profit by 9,813 $tonsCO_2e$/yr reduction. CDM validity on improvement of intake pumping efficiency was 90.2% with $124,305 mean profit by huge amount of $CO_2$ mitigation (10,347 $tonsCO_2e$/yr). System optimization of mechanical mixing process reduced 15% of energy consumption (3,184 $tonsCO_2e$/yr) and its CDM validity and mean profit was 77.25% and $23,942, respectively. Solar panel construction could make the effect of 14,094 $tonsCO_2$ mitigation annually and its CDM validity and mean profit was 64.68% and $228,487, respectively.

금속분말사출성형공법을 이용한 가솔린 터보차저의 웨이스트 게이트 밸브 어셈블리 열 충격 내구 시험 (Thermal Shock Durability Test of a Gasoline Turbocharger Waste Gate Valve Assembly Manufactured by a Metal Injection Molding)

  • 남충우;한만배;천봉수;신재식;김종하;민두식
    • 한국기계가공학회지
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    • 제13권4호
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    • pp.69-74
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    • 2014
  • A waste gate valve (WGV) assembly for a gasoline turbocharger is typically manufactured by means of precision casting. In this study, however, it was newly manufactured in a more innovative way, metal injection molding (MIM) using Inconel 713C alloy, and its performance was tested in a 1.6L direct injection gasoline engine by a thermal shock durability test that lasted 300 hours, after which the results were compared to those of a precision-cast WGV assembly with regard to the engine intake boost pressure, turbine wheel speed, and transient intake pressure. It was found that the two WGV assemblies showed similar performance levels throughout the durability test.

음용수의 섭취량 및 다경로 노출평가를 위한 노출변수 조사연구 (Daily Water Intake and Exposure Parameters Related to the Multi-route Exposure in Drinking Water)

  • 정용;신동천;박성은;최시내;박선미
    • Environmental Analysis Health and Toxicology
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    • 제11권1_2호
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    • pp.19-29
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    • 1996
  • Human exposure to volatile compounds in tap water can occur from inhalation and dermal absorption as well as direct ingestion. The relative contribution to total human exposure from these pathways has been considered to be important especially for VOC's (volatile organic compounds). In an attempt to reduce the uncertainty of the risk assessment, it has been suggested that the exposure assessment process could be significantly improved by adopting Monte-Carlo simulation. However, there is no actual data in Korea for each exposure parameter to determine the level of exposure, and the distributional pattern. Therefore, we surveyed water use patterns and behavior related to multi-route exposure to VOC's in household tap water in Korea, and compared these values to the those in western countries. In the first survey, we calculated daily water intake using data from a sample of 1322 persons of several cities in Korea. In the second survey, we obtained questionnaire data on exposure time for showering, bathing and household activities, and tap water intake from 851households in Korea. In the last survey, we measured the exposure parameters (exposure time, water use rate etc.) related to showers, baths, toilets, dish washing, washing and cooking, and tap water intake was surveyed. Also, the subjects were measured their body weight, height and tidal volume, etc. A diary, a flow meter and a measuring cup were used to measure these values as precisely as possible. Average daily water intake was ranged 0.79-1.71 L/day for adults in three surveys. Tap water intake measured by log-sheet during one week in third survey was 1.26 (average), 1.98 L/day (90 percentlie), respectively. These results were comparable with results from EPA (1.4, 2L/day). The average amount of water used by housewives in the third survey was 515.0 $\pm$ 564.6L/day. In usual activity, the amount of water used in the bathroom, the laundry and the kitchen was 140.0 $\pm$ 538.9, 148.0 $\pm$ 174.5, 229.3 $\pm$ 205.4 L/day, respectively. Exposure parameters such as water intake rate, exposure duration, body weight, inhalation rates in surveyed data of Korean people differed from those published from western countries. This could be attributed to variations in lifestyle, dietary habits and physiological characteristics.

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멀티도어코트하우스제도: 기원, 확장과 사례분석 (The Multi-door Courthouse: Origin, Extension, and Case Studies)

  • 정용균
    • 한국중재학회지:중재연구
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    • 제28권2호
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    • pp.3-43
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    • 2018
  • The emergence of a multi-door courthouse is related with a couple of reasons as follows: First, a multi-door courthouse was originally initiated by the United States government that increasingly became impatient with the pace and cost of protracted litigation clogging the courts. Second, dockets of courts are overcrowded with legal suits, making it difficult for judges to handle those legal suits in time and causing delays in responding to citizens' complaints. Third, litigation is not suitable for the disputant that has an ongoing relationship with the other party. In this case, even if winning is achieved in the short run, it may not be all that was hoped for in the long run. Fourth, international organizations such as the World Bank, UNDP, and Asia Development Bank urge to provide an increased access to women, residents, and the poor in local communities. The generic model of a multi-door courthouse consists of three stages: The first stage includes a center offering intake services, along with an array of dispute resolution services under one roof. At the second stage, the screening unit at the center would diagnose citizen disputes, then refer the disputants to the appropriate door for handling the case. At the third stage, the multi-door courthouse provides diverse kinds of dispute resolution programs such as mediation, arbitration, mediation-arbitration (med-arb), litigation, and early neutral evaluation. This study suggests the extended model of multi-door courthouse comprised of five layers: intake process, diagnosis and door-selection process, neutral-selection process, implementation process of dispute resolution, and process of training and education. One of the major characteristics of extended multi-door courthouse model is the detailed specification of individual department corresponding to each process within a multi-door courthouse. The intake department takes care of the intake process. The screening department plays the role of screening disputes, diagnosing the nature of disputes, and determining a suitable door to handle disputes. The human resources department manages experts through the construction and management of the data base of mediators, arbitrators, and judges. The administration bureau manages the implementation of each process of dispute resolution. The education and training department builds long-term planning to procure neutrals and experts dealing with various kinds of disputes within a multi-door courthouse. For this purpose, it is necessary to establish networks among courts, law schools, and associations of scholars in order to facilitate the supply of manpower in ADR neutrals, as well as judges in the long run. This study also provides six case studies of multi-door courthouses across continents in order to grasp the worldwide picture and wide spread phenomena of multi-door courthouse. For this purpose, the United States and Latin American countries including Argentina and Brazil, Middle Eastern countries, and Southeast Asian countries (such as Malaysia and Myanmar), Australia, and Nigeria were chosen. It was found that three kinds of patterns are discernible during the evolution of a multi-door courthouse model. First, the federal courts of the United States, land and environment court in Australia, and Lagos multi-door courthouse in Nigeria may maintain the prototype of a multi-door courthouse model. Second, the judicial systems in Latin American countries tend to show heterogenous patterns in terms of the adaptation of a multi-door courthouse model to their own environments. Some court systems of Latin American countries including those of Argentina and Brazil resemble the generic model of a multi-door courthouse, while other countries show their distinctive pattern of judicial system and ADR systems. Third, it was found that legal pluralism is prevalent in Middle Eastern countries and Southeast Asian countries. For example, Middle Eastern countries such as Saudi Arabia have developed various kinds of dispute resolution methods, such as sulh (mediation), tahkim (arbitration), and med-arb for many centuries, since they have been situated at the state of tribe or clan instead of nation. Accordingly, they have no unified code within the territory. In case of Southeast Asian countries such as Myanmar and Malaysia, they have preserved a strong tradition of customary laws such as Dhammthat in Burma, and Shriah and the Islamic law in Malaysia for a long time. On the other hand, they incorporated a common law system into a secular judicial system in Myanmar and Malaysia during the colonial period. Finally, this article proposes a couple of factors to strengthen or weaken a multi-door courthouse model. The first factor to strengthen a multi-door courthouse model is the maintenance of flexibility and core value of alternative dispute resolution. We also find that fund raising is important to build and maintain the multi-door courthouse model, reflecting the fact that there has been a competition surrounding the allocation of funds within the judicial system.

농산부산물(農産副産物)의 사료화(飼料化) (Improving Feed Value of Agricultural By-Products)

  • 강태홍
    • Applied Biological Chemistry
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    • 제27권
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    • pp.18-28
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    • 1984
  • In order to improve feed values of Korean agricultural by-products, various treatments including physical, chemical, physicochemical and fermentation were suggested in th is review article. Physical treatments such as chopping, grinding and pelleting reduce partiole size of agricultural by-products, and increase passage rate from the rumen, thus may increase voluntary feed intake and weight gain. Digestibility and voluntary feed intake of straw, rice hull and sawdust, also, may be increased by chemical treatment using sodium hydroxide or ammonia. Especially, because nitrogen content of by-products increase and toxic problem is not posed by ammonia treatment, it's practical usage is recommended in Korea. Silage or fermentation treatment using principles of microbial fermentation may improve palatability of low quality by-products. As mentioned above, it is concluded that various treatments suggested are desirable and improve feed value but may raise several problems. Unfortunately, because cost for installation and products is great and processing work is complicate, farmers are not using well these processing methods until now. Therefore, in order to increase the practical usage at farm level, it is thought that many research works be achieved for efficient process which have simple operation and low installation cost.

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흡입밸브 형상이 흡입유동에 미치는 영향(I) -모델에 의한 축방향속도분포- (The Effects of the Intake Value Type on the Intake Flow(I) -The Axial Velocity Distribution by the Model-)

  • 하대진;박경석
    • 오토저널
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    • 제11권6호
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    • pp.57-67
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    • 1989
  • This paper deals with the experimental study of the turbulent flow fields by the hot-wire anemometer and the density fields by the Schlieren photography. In this study, the air mixed with CO$_{2}$ was used to visualize and to study this process and experimental parameters used were valve lift and valve shape. The results obtained are as follows: 1) The axial velocity of mixture flow passing a valve is changed greatly by valve seat angle and valve lift. Especially, it is changed more when the valve seat angles is 30.deg. and 45.deg. than when these are 60.deg. and 90.deg. 2) Experimental results by hot wire anemometer and Schlieren apparatus are very close together. The most satisfactory results are shown when the valve seat angle is 45.deg.

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경승용차용 가솔린 기관의 성능향상에 관한 이론 및 실험적 연구(제2보) - 이론 해석을 중심으로 (An Analytical and Experimental Study on the Improvement of Performances of a Gasoline Engine of the Light Passenger Car (Second Paper))

  • 윤건식;서문진
    • 한국자동차공학회논문집
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    • 제9권5호
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    • pp.62-74
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    • 2001
  • In this study, the prediction of performances and emissions of the gasoline engine of a light passenger car has been accomplished. The method of characteristics including friction, heat transfer, area change and entropy gradients was used to analyze the flow in the intake and exhaust systems. For in-cylinder calculation, the single-zone model was adopted for the periods of the intake, exhaust, compression and the expansion of the burnt gas and the 2-zone expansion model was applied to the period of combustion process. The simulation program was verified by comparison with the experimental values both for the naturally aspirated engine and the turbocharged engine showing good agreements. Using the simulation program, multi-valve system and turbocharging were examined as a means of increasing engine Performances.

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Effect of Water Induction on the Performance and Exhaust Emissions in a Diesel Engine (II)

  • Ryu, Kyunghyun;Oh, Youngtaig
    • Journal of Mechanical Science and Technology
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    • 제18권9호
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    • pp.1640-1647
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    • 2004
  • This study was to investigate the effects of water induction through the air intake system on the characteristics of combustion and exhaust emissions in an IDI diesel engine. The fuel injection timing was also controlled to investigate a method for the simultaneous reduction of smoke and NOx when water was injected into the combustion chamber. The formation of NOx was significantly suppressed by decreasing the gas peak temperature during the initial combustion process because the water played a role as a heat sink during evaporating in the combustion chamber, while the smoke was slightly increased with increased water amount. Also, NOx emission was significantly decreased with increase in water amount. A simultaneous reduction in smoke and NOx emissions was obtained when water was injected into the combustion chamber by retarding more 2$^{\circ}C$A of the fuel injection timing than without water injection.

『상한론(傷寒論)』 변병진단체계(辨病診斷體系)에 근거하여 회역탕(回逆湯)을 투여하여 호전된 전신 건선 증례 보고 (A Case Report of Psoriasis Treated by Hoeyeok-tang based on Shanghanlun Provisions)

  • 이욱제;이숭인
    • 대한상한금궤의학회지
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    • 제11권1호
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    • pp.83-94
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    • 2019
  • Objective : There was an improvement in a patient with psoriasis following the intake of Hoeyeok-tang for 317 days. By analyzing these cases, we reviewed the use of Hoeyeok-tang in skin diseases and attempted to interpret the related Shanghanlun articles. Methods : The diagnostic process was analyzed according to the disease pattern identification diagnostic system based on the Shanghanlun provisions. The progression of psoriasis, which was addressed, was assessed using the PASI score. Results : The patient was diagnosed with Soeum-byung 324, and the PASI score decreased from 13.6 to 0.4 after the intake of Hoeyeok-tang for 317 days. The patient's compliance and expectation from treatment were good, and no specific adverse effect was identified. Conclusions : This study suggests the clinical use of Hoeyeok-tang in psoriasis based on Shanghanlun.