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        검색결과 210

        81.
        2013.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        For a die casting mold, generally, the casting layout design should be considered based on the relation among injection system, casting condition, gate system, and cooling system. Also, the extent or the location of product defects was differentiated according to the various relations of the above conditions. In this research, in order to optimize the casting layout design of an automotive Oil Pan_DX2E, Computer Aided Engineering (CAE) simulation was performed with two layout designs by using the simulation software (AnyCasting). The simulation results were analyzed and compared carefully in order to apply them into the production die-casting mold. During the filling process with two models, internal porosities caused by air entrapments were predicted and also compared with the modification of the gate system and overflow. With the solidification analysis, internal porosities occurring during the solidification process were predicted and also compared with the modified gate system.
        4,000원
        82.
        2013.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This review highlights the current status of Tunisian olive production, challenges facing the sector and opportunities available. Olive, a fruit tree native to Mediterranean countries, is the subject of increased international interest for olive oil production for the global food market. Olive and olive oil production in Tunisia are of great socio-economic importance, with more than 70 millions olive trees including a wide range of cultivars and represents the third important leg in fruit production. Tunisia is the 4th largest producer of olive oil in the world and oil exports represent 40% of the overall value of agronomic exports and 5.5 % of aggregate exports, making it the fifth largest source of foreign currency earnings for the country. However, the actual production of olive oil could be increased by the entire contributors in the sector and by the monitoring by government extension services. Almost 2 out of 3 farmers grow olives in the country. The crop is spread over areas from the northern to the southern regions, where a wide range of edaphon-climatic conditions prevail, from lower semi-arid to arid conditions and receiving annually less than 250 mm of rain-fall (IOOC, 2003). So far, most of the production has been done using traditional techniques and under rainfed conditions. This translates into extremely erratic production levels depending on the year. The major challenges for olive production and for Tunisian producers are to improve fruit and oil quality in order to maintain their competitiveness on the international oil market and to meet consumer demands. The major opportunity available to develop Tunisian olive sector is primarily the improvement of yields, the raising of productivity and oil quality and meet the recent boom in demand for olive oil and table olive around the world.
        4,000원
        84.
        2013.10 구독 인증기관 무료, 개인회원 유료
        When manufacturing die casting mold, generally, the casting layout design should be considered based on the relation among injection system, casting condition, gate system, and cooling system. Also, the extent or the location of product defects was differentiated according to the various relations of the above conditions. In this research, in order to optimizing casting layout design of an automobile part (Oil Pan_DX2E) Computer Aided Engineering (CAE) simulation was performed with two layout designs by using the simulation software (AnyCasting). The simulation results were analyzed and compared carefully in order to apply them into the production die-casting mold. During the mold filling with two models, internal porosities caused by air entrap were predicted and also compared by the modification of the gate system and the configuration of overflow. With the solidification analysis, internal porosities caused by the solidification shrinkage were predicted and also compared by the modification of the gate system.
        3,000원
        85.
        2013.09 구독 인증기관·개인회원 무료
        The oil sands are loose sand or partially consolidated sandstone containing naturally occurring mixtures of sand, clay, and water, saturated with a dense and viscous from of bitumen. Natural bitumen deposits are found in large quantities in Alberta and Utah area. Nevertheless of its environmental issues, a large-scale commercial oil sands industry is expected to increase in coming decades.(1) The present paper focuses on physico-chemical analysis of two different types of bitumens. These bitumen samples were chosen based on: the original source (oil sand and crude petroleum), and mode of process. The aim of this study is to determine both the manufacturing effect on chemical species and the chemical organization as a function of the type of bitumen sample. In order to obtain information on bitumen chemistry, elemental analysis (C, H, N, S, and O), heavy metal (Ni, V) concentrations, IATROSCAN chromatography (thin layer chromatography-flame ionization detection), FTIR spectroscopy, and NMR spectroscopy (1H NMR,13C NMR)haveallbeenused.The characterization includes information about the major compound types (saturates, aromatics, resins and asphaltenes) which can be compared with similar data for other bitumens, more importantly, can be correlated with data from petroleum samples for which refining characteristics are known. Examination of oil sand asphalt showed that it differed significantly from representative petroleum residues, principally in their nonhydrocarbon content and aromatic compounds. When possible, properties and composition were related to recovery and refining processes. This information is important because of the effects that composition has on recovery and processing reactions.
        86.
        2013.09 구독 인증기관·개인회원 무료
        전 세계적으로 산업의 고도화로 인하여 환경오염이 급속도로 진행되고 있으며, CO2 발생의 증가로 지 구 온난화 현상이 급속도로 진행되고 있다. 기존의 일반 아스팔트포장은 약 160℃의 고온에서 생산 및 시공되기 때문에 CO2가 크게 발생되며, 시멘트포장 또한 시멘트 생산 시 CO2가 발생되고 있다. 최근 강상판 장대교량(케이블교)의 건설이 증가하고 있으며, 사하중을 절감하기 위한 박층 폴리머 콘크리트가 개발되고 있다. 그러나 폴리머 수지도 석유계 재료로 생산되기 때문에 CO2가 발생되며 석유자원 의 고갈로 인한 폴리머 수지의 가격 상승 등이 문제점으로 부각되고 있다. 이러한 문제점의 대안으로 식물성 수지를 사용한 바이오 폴리머 수지를 개발하는 연구가 지속적으로 수행되고 있다. 그러나 식물성 재 료를 사용하게 되면 기존 석유계 수지에 비하여 강도 및 환경 영향에 대한 물리적 특성이 감소하는 문제 가 발생하여 차량하중의 영향이 작은 주차장, 보도, 자전거 도로 등에 적용되고 있는 실정이다. 본 연구에서는 기존 석유계수지의 약 30~50%를 식물성 재료로 대체한 도로포장용 바이오 폴리머 수지를 개발하고자 한다. 식물성 재료는 콩유(Soybean Oil), 피마자유(Castor Oil), 야자수유(Palm Oil) 등 그 종류가 다양하지만 폴리올(Polyol)공정을 거치지 않고 생산이 가능한 피마자유를 이용하여 생산비용을 절감하였으며, 환경 영향 저항성과 관련된 시험을 수행하여 도로포장에 대한 적용성을 평가하였다. 식물 성 재료가 약 30% 첨가된 수지(906-3)와 50% 첨가된 수지(2I)를 대상으로 무처리 상태의 강도와 처리 후(동결융해, 자외선)의 강도를 측정하여 비교·평가하고 염화물에 대한 저항성을 시험하였다. 그 결과 기 존 석유계 폴리머 수지에 식물성 재료를 50% 대체하여도 강도변화가 미미한 결과를 도출하여 바이오 폴리머 수지를 도로포장에 적용하여도 문제가 없음을 확인하였다.
        87.
        2013.05 구독 인증기관·개인회원 무료
        When manufacturing die casting mold, generally, the casting layout design should be considered based on the relation among injection system, casting condition, gate system, and cooling system. Also, the extent or the location of product defects was differentiated according to the various relations of the above conditions. In this research, in order to optimizing casting layout design of an automobile part (Oil Pan_DX2E) Computer Aided Engineering (CAE) simulation was performed with two layout designs by using the simulation software (AnyCasting). The simulation results were analyzed and compared carefully in order to apply them into the production die-casting mold. During the mold filling with two models, internal porosities caused by air entrap were predicted and also compared by the modification of the gate system and the configuration of overflow. With the solidification analysis, internal porosities caused by the solidification shrinkage were predicted and also compared by the modification of the gate system.
        88.
        2013.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Numerical analysis has been carried out to investigate thermal characteristics for hydraulic system. Overall performance of hydraulic system is largely influenced by oil flow field with heat transfer. Especially thermal characteristics for operating conditions with high oil temperature caused by heavy load and continuous operation are dominant. Oil temperature variation with time in the system is predicted for various flow conditions. Local fluid flow fields at the pipelines, valves, and oil pump in the hydraulic system are considered with thermodynamic and transport properties such as density and viscosity. These results in the study can be applied to the optimal design of hydraulic system.
        4,000원
        89.
        2012.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        When gasoline car using gasoline additives and lubricant additives was running, we were able to find the characteristics which is related to noise and vibration, and also affection of emission by chassis dynamometer. The results are followed. 1) change of HC was not related to lubricant additives, it turned out that change of HC will be low, when ratio of gasoline additives is high. 2) NOx was detected to high, when ratio of lubricant additives is high. And when ratio of gasoline additives was 8.29, the data for NOx was lowest. 3) CO2 was 13.5~14% constantly, this result is not related to ratio of lubricant additives and gasoline additives. 4) Noise was not related to both of them ratio of lubricant additives and gasoline additives. But vibration was downed to 120Hz at 40km/h due to lubricant additives.
        4,000원
        90.
        2012.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        홍삼에서 사포닌 추출과정 중 부산물로 얻어지는 홍삼오일의 화학적 특성 및 화장품소재로서의 응용가능성을 알아보고자 하였다. Tween 80으로 희석한 1% 홍삼오일의 산가는 0.265, 과산화물가는 0.387, 요오드가는 0.64이었다. DPPH free radical scavenging assay 결과, 1% 홍삼오일은 대조군인 동일 농도의 α-tocopherol에 비해 70% 정도의 항산화능을 나타내었다. 홍삼오일의 total polyphenol 함량은 243 mg/100 g이었다. Tyrosinase저해 활성을 측정한 결과, 홍삼오일은 대조군인 L-ascorbic acid에 비해 14% 정도의 활성억제 효과를 나타내었다. 홍삼오일에 의한 elastase 활성억제 효과는 거의 없었으며 홍삼오일의 Staphylococcus aureus와 Escherichia coli 에 대한 생육억제 효과도 없었다.
        4,000원
        92.
        2012.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        다양한 화장품에 응용을 위하여 제주산 유채오일 추출물을 대상으로 PIT유화시스템을 이용한 나노에멀젼을 제조하였다. 천연 유채오일 추출물은 n-헥산을 용매로 사용하여 추출하였다. 천연유채오일 추출물은 엷은 노란색의 점성을 가진 액체이었고, 수율은 43±2.5%이었다. 산가는 2.76±0.5이었고, 비중은 0.89±0.05 이었다. 20wt%의 유채오일을 사용한 PIT-Yuche-NE의 입자크기는 50-120nm (평균입자크기: 82±5.8nm)이었고, 제타 포텐셜은 -29.5mV 이었다. 이것은 (PEG)5-30 지방산 에테르를 사용하기 때문에 열역학적으로 안정하였다. 특징적인 결과로부터 얻은 몇 개의 결론을 다음과 같이 나열하였다. 첫째, DPPH (1,1-diphenyl-2-picrylhydrazyl radical)방법을 이용한 자유 라디칼 소거력을 측정하였다. PIT-Yuche-NE의 항산화력은 37.2±6.7%이었고, 비교군인 10 mg/mL의 PIT-Toco-NE(토코페롤 20wt% 나노에멀젼)은 28.8±6.5%, 10 mg/mL의 PIT-Nokcha-NE (녹차추출물 20wt% 나노에멀젼)은 29.6±7.2%이었다. 둘째, PIT-Yuche-NE의 콜라겐합성율은 148±15.2% 이었고, 동일 농도에서 비교군인 PIT-Toco-NE은 121±13.5%, PIT-Nokcha-NE은 95±12.7%이었다. 셋째, 6시간 후, Aramo-TS를 사용한 Yuche-CRM의 피부보습효과는 47±3.9% (*p-value£0.05, n=7)이었다. 반면, Toco-CRM은 30±5.2%(*p-value£0.05, n=7)이었고, Nokcha-CRM은 35±4.5%이었다. 따라서 Yuche-CRM은 다른 두 크림보다 높은 보습효과를 보였다. 최종적으로 본 연구는 화장품 산업 및 제약산업에서도 폭넓게 응용될 것으로 기대한다.
        4,000원
        94.
        2012.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        오미자 씨 오일의 화장품 소재로서 가능성을 평가하기 위해 GC와 GC/MSD를 사용하여 안정성 평가 및 성분 분석을 실시하였다. 그 결과 주요성분은 팔미틱산과 올레익산으로 나타났다. 오미자 씨 오일은 열에 의한 성분변화가 없고, 소재 자체의 안정성이 뛰어난 것으로 나타났다. 또한, DPPH(1,1-Diphenyl-2-picrylhydrazyl) 라디칼 소거능 실험을 통하여 항산화 효능을 측정한 결과 오미자 씨 오일이 마카다미아 오일과 올리브 오일에 비하여 높은 항산화 효능을 나타내었다. 콜라겐 합성능 또한 뛰어난 것으로 평가되었다. 따라서, 오미자 씨 오일은 화장품 소재용으로 유용하게 활용될 수 있는 가능성을 가진 것으로 평가되었다.
        4,000원
        95.
        2012.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This research aims to develop parts for Advanced Fuel/Oil Filtering Re- circulation applicable to this kind of regulation proof engines. These parts can play a role of converting traditional air emission type crankcase into recovery type crankcase so that the engine can deal with environmental regulations, which do not allow minimal amount of toxic gas discharge. For the experiment, test method and specially made testing equipment are prepared. The results showed that Oil separation efficiency of the Cyclone type crank case oil separator was higher than one of the partition wall type in bench test and that Emission gas of the cyclone type oil separator was higher than one of the partition wall type in vehicle test.
        4,000원
        96.
        2012.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        High power and high efficiency has been required in internal combustion engine. Accordingly, the thermal load deformation, thermal stress and temperature on piston become higher at newly developed engines. To investigate the cooling effect of piston, a few types of piston design is presented and finite element method is carried out to analysis the heat transfer and the thermal stress. The piston which has upwards shifted cooling gallery is also analyzed to investigate the thermal load effect of oil jet cooling.
        4,000원
        97.
        2012.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Experimental analysis has been carried out to investigate oil temperature control characteristics of the hydraulic system in a special vehicle. Hydraulic system performance is largely affected by oil temperature, and there are considerable malfunctions in the system for high temperature conditions caused by heavy load and continuous operation. Oil pressure in the hydraulic system decreases with oil temperature, and its variation rate becomes less steep as oil temperature increases. There is severe time delay for oil temperature control due to the operation of heat exchanger system, and it depends on the oil flow rate and pressure in the system. These results in this study can be applied to the design of automatic thermal control system in the special vehicle hydraulic system.
        4,000원
        98.
        2011.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Transparent liquid crystal gels with high oil content by fatty acid soap were investigated. The solubilization efficiency of the mineral oil was dependent on the process. The process of dropping water part into the solution of oil and surfactant was more efficient than the process of dropping water part into the surfactant solution and after that dropping oil. The fatty acid soap could not solubilize the high oil content, but under the certain range, addition of CDE (Coconut Diethanolamide), Arlacel 165 (Glyceryl Stearate/PEG-100 Stearate) and cetostearyl alcohol helped solubilize the high content oil. Also, the glycerin and water content had influence on the solubilization. Especially, higher oil content gel showed elastic feature.
        4,000원
        99.
        2011.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Hydrophobic nanodiamond (ND) were dispersed in engine oil (Helix Oil, Shell co.) as an additives to improve tribology properties. In this study, nanodiamond prepared by an explosive method was used. Tribology properties of both pure Helix oil and engine oil containing ND additive were evaluated. The rotating disks were made of Gray Cast Iron (240 Hv) and SKD11 (710 Hv). Surface topographies of the disks' wear tracks and friction coefficient were compared. The results show that nanodiamond-dispersed lubricants are capable of reducing these metals' wear loss. The friction coefficient is strongly affected to the hardness of wear track.
        4,000원
        100.
        2011.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In general, a valve body of the automatic transmission(AT) is controlled by the clutch, the brake and lubricating oil flow in a hydraulic system and lubricant flow for each valve can be adjusted independently. To increase the lifetime of AT, the lubrication flow rate in a valve body for a 6 speed AT based parallel hybrid electric vehicle must be provided with proper oil distribution and control. In this study, we carried out several experiments without the inner parts of AT and with a AT assembly. The variation of the flow rate on oil temperature and pressure between an oil supply port and the outlets of the lubrication port was evaluated and analyzed. In the case of AT without the inner parts, it was evident that as the oil required for an operation of the clutch and brake was discharged from the outlet port, the flow rate from each lubrication port is decreased. However, the flow rate of the AT assembly was slightly increased. In addition, the lubrication flow rate was increased with increasing the oil temperature, and also it was reduced with increasing the oil pressure. Details of the resulting data are discussed.
        4,000원
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