• 유기물자원화
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• 제19권1호
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• pp.86-92
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• 2011

화석에너지 의존도를 줄이면서 $CO_2$ 배출량을 낮추기 위하여 정부에서는 녹색마을을 선정하고 에너지 자급률을 40% 수준으로 높이려는 계획을 추진 중이다. 본 연구는 각 농업 분야 중에서 농기계의 사용과 재배 시설에 있어서의 에너지 사용량을 파악하고 이를 바이오디젤로 대체하였을 때의 $CO_2$ 저감수준을 분석하고자 하였다. 이를 위하여, 농업 각 분야별 에너지 소비수준의 분석, 그리고 실천 가능한 신재생 에너지원의 선정이 요구된다. 경종재배의 전체 연간온실가스 배출량은 $5,667,258\;t-CO_2$이고, 그 중 시설 부문은 $4,932,607\;t-CO_2$인 것으로 분석되었으며, 농업시설 부문 중 에너지원별로 보면 경유가 $3,105,707\;t-CO_2$, 중유가 $1,370,578\;t-CO_2$를 배출하는 것으로 분석되었다. 우리나라 시설작물의 단위 면적당 온실가스 평균배출량은 $29,418\;t-CO_2/ha$인 것으로 나타났다. 농기계별 2007년 총에너지소비량을 살펴보면 트랙터가 284,763 kL로 가장 높게 나타났으며, 동력 경운기 221,314 kL, 곡물건조기 145,524 kL, 콤바인 72,537 kL 등의 순이었다. 전라북도 G시를 대상으로 이용 중인 시설재배와 농업기계의 이산화탄소 배출량을 비교분석한 결과, 바이오디젤로 전환하면 약 7% 정도의 $CO_2$ 감소효과가 있는 것으로 분석되었다.

• 한국자동차공학회논문집
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• 제22권3호
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• pp.81-89
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• 2014

This study researched on the effect of HP/LP-EGR system to improve fuel consumption of Low Temperature Combustion Engine. Firstly, low temperature combustion engine with HP/LP-EGR system was established using 6.0L wastegate turbocharger HDDI engine. And suppliable EGR rate of the engine was proven to be enough to realize stable low temperature combustion. Then, optimum operating strategy was founded to develop fuel consumption of the engine. Control parameters were HP/LP-EGR valve and IPCV(Intake Pressure Control Valve) duty. Experiments method was that characteristics of the engine were measured and analyzed according to HP/LP-EGR strategies while EGR rate was fixed. Operating range for the strategy were divided into three parts, low load for low temperature combustion, high load for conventional diesel combustion, and transient condition. Finally, with the above strategy of this study, BSFC of the engine was improved about 2% compared to the base engine, and emission level, NOx and PM, met Tier4Final emission regulation.

• Journal of the Korean Wood Science and Technology
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• 제10권3호
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• pp.194-195
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• 1982

Recommendaton: These are the highlights of the findings of the Timber Consumption Survey carried out by the Project in 1966, and covering consumption for the period from 1961 to 1965. The survey was oriented towards consumption for structural, commercial and industrial purposes and existing estimates for local (village-level) consumption as fuel and the like were adopted. A full report on the survey was submitted to the Bureau of Forestry in 1966. Long-term Trends: After allowance for anticipated population increase, this ten year's increase in industrial wood consumption represents a gain of about 30% in per capita consumption (from 0.0913 cu.m. per capita to 0.118 cu.m. per capita). This is only about half the expected general economic growth of about 75% (7% per annum). It is therefore likely (a) that the 1975 estimate is conservative, (b) that the consumption demand beyond 1975 may be expected to build up at a greatly increased rate. Estimated income elasticity coefficients are high, and with expected ir,creases in prosperity and population, the consumption is expected to rise to 10 million cu. meters by the year 2,000. Consumption Pattern: The breakdown of industrial consumption (1965) is given in Table 4-2, showing sawnwood consumption as the most important in 1965. The upward trend in all sectors over the 1961-65 period is expected to continue. The general consumption pattern is expected to change through 1975 with a sharp increase in the relative importance of pulp products (to 30% of total consumption) offset by declining relative importance of sawlogs. The following recommendations follow from the study: (i) Industrial forests. - A programme of establishment of consolidated industrial forests should be initiated as a matter of urgency. (ii) Fuelwood forests - Properly sited, protected and managed fuelwood forest, worked on a 20-year rotation, should be established as a nation wide basis. (iii) Hardwood utilization - Detailed investigations are required into the use of indigenous hardwoods for the pulp, particle board and hardboard industries. (iv) Mining timber - Preservation treatment of all mining timber should be enforced by law. (v) Sawmills - Licencing restrictions should be enforced to reduce the number of small, inefficient sawmills. b. Extension work should be undertaken bv government to improve sawmilling practices.

• Tribology and Lubricants
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• 제25권5호
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• pp.311-317
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• 2009

To satisfy the more severe emission regulation and the demand of higher fuel economy in near future, the combustion pressure and power output of engines is going to be higher. In order to get the reduction of engine emission and the higher power, it is needed the reduction of the tension and width of ring pack. The lower tension ring and the thinner width ring can bring not only the friction reduction between the ring and liner during engine running, but also the adjustment of the blow-by gas and oil consumption by changing in the pressure in the crevice volume and the axial motion of rings togethe with the adjustment of the inter-ring crevice volumes. In this study, by using a developed basic computer proglram that predicts the blow-by gas and oil consumption of engines, it is to be examined how satisfying the level of the blow-by gas and oil consumption as being installed the piston ring pack with thinner width ring and lower tension ring.

• 대한가정학회지
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• 제8권1호
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• pp.181-197
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• 1970

Farm households consumption pattern from 1960 to 1968 was analized as follows. First, the influence of the price on the consumption pattern was observed by year for 9 years. Second, the influence of farm households and by size of the consmption pattern was analized by year for whole household and by size of the arable land. Third, the present status and problems of farm families consumption pattern was attempted to be found out compared with the pattern of all families of Seoul. Forth, the pattern of food expenditure which has the largest proportion in the living expenditure was analized. Following results and conclusions are obtained from the above analysis.1. The average nominal increase rate of all farm households has been increased gradually for 9 years, mostly due to the rise in household goods prices paid by farmers. 2. The living expenditure varies with the price and the disposal income, The influence of the latter is greater than that of the former. 3. The Engel's Coefficient of farmers. the average of which was 54.9%, recently tends to decrease gradually. The larger is the size of arable land, the lower is the Coefficient of farm households. But the Coefficient of farm households is higher than that of city families. 4. In general the proportion of food expenditure has a great influence on the consumption pattern, The average percentage of miscellaneous expenditure is 23.9% and it is next to food expenditure. The relationship between them is going reversely. Housing expenditure has usually the constant proportion. But the difference of the proportion between farm households (4.0%) and city families (17.1%) is considerable. Clothing expenditure and fuel and light expenditure have small variations. The former tends to increase with the income, and the latter tends to decrease with it or is constant. 5. Considering the food expenditure pattern, the average percentage (78.4%)of staple food of farm household is remarkably high compared with Seoul (48.3%) and other cities (54.0%). The decrease of the percentage of staple food expenditure in farm households is not so much as cities. 6. The propertion of the staple food expenditure of Farm families don't have so much differences by the size of arable land. But the rice proportion of staple foods has the tendency to increase with the income level. Subsidery food expenditure doesn't increase by year and by size of the land, while the consumption of meat and manufactured foods tends to increase with size of the land. But even big farm households don't reach to the level of cities in consumption of them. 7. Food consumption pattern may be influenced by the factors such as the knowledge of wife about nutrition, customs, consumption habits, and so on. The difference between farm households and city families in food consumption pattern is inferred from the above factors. Presently, the increasing income of the people promote the consumption of all items of living expenditure both in cities and farm households. But the Engel's Coeffcient and the proportion of the staple food expenditure is expected to decrease in farm households more than in cities.

• Journal of Advanced Marine Engineering and Technology
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• 제41권4호
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• pp.323-329
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• 2017

최근 전 세계 기온상승, 해양에서 오염물질 배출 규제 강화 등을 고려할 때 운항선도 연료 절감을 의무적으로 이행해야 한다. 항내에서 오염물질 배출에 대한 IMO 국제기준 및 EU 각국의 제한기준이 강화되고 있다. 따라서 선사와 조선업계에서는 $CO_2$, SOx, 및 NOx 배출을 저감하는 방안에 대하여 모색하고 있다. 지속적인 무역 증가와는 반비례하여 해상운송에 사용되는 연료량은 줄어드는 경향이 있다. 하지만 국제해운 회의소는 2050년까지 해운으로부터 배출되는 이산화탄소를 50% 감축한다는 목표를 설정하였다. 또한 2015년 신기후변화협약이라 불리는 파리 기후협약과 관련하여 IMO는 운항 선박으로부터 온실가스 배출 감축 목표를 설정하기로 제안하였다. 국제 해운수송에서 배출되는 온실가스 배출 감축 목표를 설정하기 위해 연료 데이터수집시스템이 도입될 예정이다. 운항선 연료절감 강제화 추세에 따라 선박으로부터 효과적인 연료 사용 감축을 유도하기 위해, 이 논문에서는 연간 운항 결과를 EEOI로 검증한 후 탄소배출권 거래제 및 탄소세에 기반 한 격려금과 벌과금 부여 제도의 운영과 이에 적용할 기초 식을 제안하였다.

• 대한기계학회논문집B
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• 제28권12호
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• pp.1467-1474
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• 2004

Recently, with respect to an increase of energy consumption, many countries have tried to develop alternative fuels. In the United States, less than 10 percent of motor fuels will be displaced by alternative fuels by year 2010, with about 25 percent of the replacement fuels from renewable resources. But the level of exhaust gas is not decreased to the result of an increase of diesel vehicles. Moreover, emission regulations are being intensified by advanced countries such as America and Europe. Because Biodiesel is similar to diesel fuel, it is essential to judge the environmental and health effects deriving from the use of Biodiesel in diesel engine. Therefore, this research could be conformed whether both Biodiesel 20% and Biodiesel 100% are influenced on emission according to sulfur contents by applying DOC. As a result of using the Biodiesel, this research could be conformed though Nox was increased, CO, HC and PM were decreased, and also estimated to compare diesel fuel with the Biodiesel in accordance with engine performance and emission characteristics.

• International Journal of Aeronautical and Space Sciences
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• 제5권1호
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• pp.46-56
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• 2004

The verification and improvement of the measurement uncertainty have beenperformed in the altitude test facility for small gas turbine engines, which was built atthe Korea Aerospace Research Institute (KARI) in October 1999. This test is performedwith a single spool turbojet engine at several flight conditions. This paper discussesthe evaluation and validation process for the measurement uncertainty improvements usedin the altitude test facility. The evaluation process, defined as tests before the facilitymodification, shows that the major contnbutors to the measurement uncertainty are theflow meter discharge coefficient, the inlet static and total pressures, the cell pressureand the fuel flow rate. The measurement uncertainty is focused on the primary parametersof the engine performance such as airflow rate, thrust and specific fuel consumption (SFC).The validation process, defined as tests after the facility modification, shows that themeasurement uncertainty, in seal level condition, is tmproved to the acceptable level throughthe facility modification. In altitude test conditions, the measurement uncertainties arenot improved as much as the uncertainty in sea level condition.

• 한국자동차공학회논문집
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• 제8권5호
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• pp.1-11
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• 2000

This study is aimed to develop a proto-type LPG engine for medium-duty commercial vehicles in order to substitute for conventional diesel engine. Recently, it is recognized that diesel engines are main cause for smoke pollution in urban site. So, it is expected to reduce this environmental emission by developing and substituting LPG engine which has the advantage of practical use in a short development period in aspects of infrastructures. For that, after analysing the specifications and performance characteristics of a base diesel engine, parts of combustion chamber, intake system, fuel supply and ignition systems suitable for LPG combustion were re-designed and manufactured. And and engine controller for fuel supply and ignition distributions was matched by feedback mapping based on the speed-load conditions. The torque and power of LPG engine were increased by 6∼12% on the overall driving conditions compared to the base diesel engine, and fuel consumption rate marked the similar level based on the fuel price. Exhaust emissions such as THC, CO, NOx recorded the same order with conventional LPG engine for passenger car.

• 동력기계공학회지
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• 제20권5호
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• pp.60-65
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• 2016

Dynamic performance of transmission has a substantial effect on dynamic performance and fuel efficiency of a vehicles. Dynamic performance of transmission and mass moments of inertia of transmission gears are related directly each other. Then a smaller amount of kinetic energy from vehicles that repeat acceleration and deceleration requires lighter rotating part in transmission. It is going to increases fuel efficiency as a result. In this study, equivalent inertia moments of inertia at different speeds were calculated by simplifying the transmission system. To find out lightening effect at low speed level gear on fuel efficiency, the powerflow of transmission was analyzed. And the lightning effect of the rotating parts in transmission is compared with the mass reduction of sprung parts in vehicle.