• 소성∙가공
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• 제10권1호
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• pp.15-22
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• 2001

The sensitivity method has been utilized to find initial blank shapes which transform into desired shapes after forming. From the information of die shapes, target shape and material properties, the corresponding initial blank which gives final shape after deformation has been found. Drawings of a trapezoidal cup, a cross-shaped cup and an oil pan have been chosen as the examples. At every case the optimal blank shape has been obtained only a few times of modification without any predetermined deformation path. With the predicted optimal blank, both computer simulation and experiment are performed. Excellent agreements are recognized between simulation and experiment at every cases Through the investigation, the sensitivity method is found to be effective in obtaining optimal blank shapes in drawing of complex shapes.

• 산업경영시스템학회지
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• 제40권1호
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• pp.35-40
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• 2017

A most important progress in civilization was the introduction of mass production. One of main methods for mass production is die-casting molds. Due to the high velocity of the liquid metal, aluminum die-casting is so complex where flow momentum is critical matter in the mold filling process. Actually in complex parts, it is almost impossible to calculate the exact mold filling performance with using experimental knowledge. To manufacture the lightweight automobile bodies, aluminum die-castings play a definitive role in the automotive part industry. Due to this condition in the design procedure, the simulation is becoming more important. Simulation can make a casting system optimal and also elevate the casting quality with less experiment. The most advantage of using simulation programs is the time and cost saving of the casting layout design. 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_BR2E, Computer Aided Engineering (CAE) simulation was performed with three 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 three models, internal porosities caused by air entrapments were predicted and also compared with the modification of the gate system and overflows. With the solidification analysis, internal porosities occurring during the solidification process were predicted and also compared with the modified gate system.

• 산업경영시스템학회지
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• 제42권1호
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• pp.1-7
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• 2019

In the modern industrial period, the introduction of mass production was most important progress in civilization. Die-casting process is one of main methods for mass production in the modern industry. The aluminum die-casting in the mold filling process is very complicated where flow momentum is the high velocity of the liquid metal. Actually, it is almost impossible in complex parts exactly to figure the mold filling performance out with the experimental knowledge. The aluminum die-castings are important processes in the automotive industry to produce the lightweight automobile bodies. Due to this condition, the simulation is going to be more critical role in the design procedure. Simulation can give the best solution of a casting system and also enhance the casting quality. The cost and time savings of the casting layout design are the most advantage of Computer Aided Engineering (CAE). Generally, the relations of casting conditions such as injection system, gate system, and cooling system should be considered when designing the casting layout. Due to the various relative matters of the above conditions, product defects such as defect extent and location are significantly difference. In this research by using the simulation software (AnyCasting), CAE simulation was conducted with three layout designs to find out the best alternative for the casting layout design of an automotive Oil Pan_BJ3E. In order to apply the simulation results into the production die-casting mold, they were analyzed and compared carefully. Internal porosities which are caused by air entrapments during the filling process were predicted and also the results of three models were compared with the modifications of the gate system and overflows. Internal porosities which are occurred during the solidification process are predicted with the solidification analysis. And also the results of the modified gate system are compared.

• 한국식품영양과학회지
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• 제41권12호
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• pp.1813-1822
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• 2012

본 연구에서는 기능성이 뛰어난 자맥가루와 올리브유를 첨가한 제빵개발을 위해 중심합성계획법에 따라 자맥가루와 올리브유의 양을 독립변수로 하여 빵을 제조한 후, 품질특성을 조사하고 반응표면분석법을 이용하여 최적배합비를 구하였다. 실험 결과 이화학적 특성과 물성 중 무게, 부피, 비용적, 명도, 황색도, 경도, 탄력성, 응집성, 검성, 씹힘성이 linear 모델이 채택되었으며, 적색도는 quadratic 모델이 채택되었다. 관능적 특성 중에서는 색, 외관, 조직감, 맛, 전체적 기호도가 linear 모델이 채택되었고, 향은 이차 회귀분석의 설명력이 부족한 것으로 나타났다. 이화학적 특성과 물성 중 자맥가루 첨가량이 증가할수록 무게, 황색도, 경도, 검성, 씹힘성이 증가하였고 부피, 비용적, 명도, 탄력성은 감소하였다. 올리브 첨가량이 증가하면 경도, 응집성, 검성, 씹힘성은 증가하고, 황색도, 탄력성은 감소하였다. 이화학적 특성과 물성 특성에 자맥가루 첨가량에 대한 영향이 올리브유 첨가량에 대한 영향보다 컸다. 관능특성 검사 결과, 자맥가루 첨가량이 증가할수록 향을 제외한 모든 기호도가 감소하였으며, 올리브유에 의한 영향은 거의 없었다. 관능특성 중 유의성이 있었던 항목의 최대값을 충족시키는 최적의 배합비율은 자맥가루 10.00%, 올리브유 1.45%로 이 경우에 기호도는 색 6.45, 외관 6.60, 조직감 6.13, 맛 5.96, 전체적 기호도 6.37로 산출되었다. 또한 다소 관능평가 점수가 낮아지더라도 자맥가루를 첨가량을 최대로 늘릴 수 있는 방안을 모색한 결과, 자맥가루가 15.85~22.10%에서는 올리브유 첨가량에 관계없이 5.0의 전체적 기호도를 보였고, 자맥가루가 14.62% 이하일 때 올리브유 첨가량에 관계없이 6.0 이상의 전체적 기호도를 보였다. 본 연구 결과는 자맥가루와 올리브유를 이용한 식빵을 비롯한 기능성식품의 개발에 있어 기초자료로 이용될 것으로 기대된다.

• Toxicological Research
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• 제31권3호
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• pp.307-312
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• 2015

Trans fat is a unsaturated fatty acid with trans configuration and separated double bonds. Analytical methods have been introduced to analyze trans fat content in foods including infrared (IR) spectroscopy, gas chromatography (GC), Fourier transform-infrared (FT-IR) spectroscopy, reverses-phase silver ion high performance liquid chromatography, and silver nitrate thin layer chromatography. Currently, FT-IR spectroscopy and GC are mostly used methods. Trans fat content in 6 vegetable oils were analyzed and processing effects including baking, stir-frying, pan-frying, and frying on the formation of trans fat in corn oil was evaluated by GC. Among tested vegetable oils, corn oil has 0.25 g trans fat/100 g, whereas other oils including rapeseed, soybean, olive, perilla, and sesame oils did not have detectable amount of trans fat content. Among cooking methods, stir-frying increased trans fat in corn oil whereas baking, pan-frying, and frying procedures did not make changes in trans fat content compared to untreated corn oils. However, the trans fat content was so low and food label can be declared as '0' trans based on the regulation of Ministry of Food ad Drug Safety (MFDS) (< 2 g/100 g edible oil).

• 한국식품과학회지
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• 제44권5호
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• pp.526-531
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• 2012

Olive oil is widely consumed in Korea, and is a representative fat source in the Mediterranean diet, known to be effective in the prevention of coronary artery disease. In addition, diverse functionalities have been reported, such as anti-cancer, anti-oxidation, and anti-inflammation effects. In this review, the status of production and variety were investigated with respect to the functionalities of olive oil. The main functional constituents of olive oil are oleic acid, known to improve blood cholesterol, and the minor constituents are polyphenol, tocopherol, squalene, and phospholipid, the concentrations of which can be used to distinguish pressed from refined olive oil. A number of studies of the functionality of olive oil have dealt with the minor constituents, and the beneficial functionalities, such as anti-oxidation, anti-inflammation, and improving blood circulation have been reported. This review intensively investigates the functionalities and the responsible components, and suggests that continual studies on olive oil are necessary for the prevention of various metabolic diseases.

• Tribology and Lubricants
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• 제24권6호
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• pp.285-290
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• 2008

The purpose of this paper is to present the case study of tribological failure analysis on the gear damages, oil leakage, and sealant sealing in a manual transmission of front engine and front wheel drive vehicle. The manual transmission is to change the speed range and direction of the engines depending on the driving conditions by friction driving forces with input and output gear system. The material property and surface roughness of the gears are strongly related to the gear noise and micro-vibration, oil leakage and wear, which may decrease the real contact area of the gear and the strength of the oil film thickness between the driving gear and driven one. The O-ring damage of speedometer driven gear and bad sealant sealing of oil pan may produce oil leakage through the contact surfaces, which cause the oil shortage and seizure on the sliding surfaces of the transaxle gears. In the failure case study, the proper repair working and good lubrication are very important for the long life of the transaxle without any tribological failures and oil leakage.

• 한국식품과학회지
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• 제45권2호
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• pp.180-190
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• 2013

흑맥가루와 올리브유를 첨가하여 식빵의 영양성과 기호성을 개선하기 위해, 밀가루 대체 흑맥가루 첨가량은 6-34%로, 쇼트닝 대체 올리브유 첨가량은 0.6-3.4%로 첨가량을 달리 하여 식빵을 제조한 후 반응표면분석법으로 최적화하여 최적조건을 구하고자 하였다. 실험결과 이화학적 특성과 물성 중 무게, 부피, 비용적, 명도, 적색도, 황색도, 경도, 탄력성, 응집성, 씹힘성이 linear 모델이 채택되었으며, 검성은 quadratic 모델이 채택되었다. 관능적 특성 중에서는 색, 외관, 조직감, 맛, 전체적 기호도가 quadratic 모델이 채택되었고, 향은 이차 회귀분석에 대한 설명력이 부족한 것으로 나타났다. 이화학적 특성과 물성 중 흑맥가루와 올리브유 첨가량이 증가할수록 무게, 적색도, 경도, 응집성, 검성, 씹힘성이 증가하였고 부피, 비용적, 명도, 황색도, 탄력성은 감소하였다. 이화학적 특성과 물성 특성에 흑맥가루 첨가량에 대한 영향이 올리브유 첨가량에 대한 영향 보다 컸다. 관능특성 검사 결과 향을 제외한 모든 관능검사 항목에서 흑맥가루와 올리브유 첨가량에 의해 증가하다가 감소하는 경향을 볼 수 있었으며, 올리브유에 대한 영향은 흑맥가루 첨가량에 대한 영향보다 적었다. 관능특성 검사 결과 중 유의성이 있었던 모든 항목의 최대값을 목표범위를 충족시키는 최적의 배합비율은 흑맥가루 18.00%, 올리브유 1.80%로 산출되었다. 본 연구 결과는 흑맥가루와 올리브유를 이용한 식빵을 비롯한 기능성 식품의 개발에 있어 기초자료로 이용될 것으로 기대된다.

• Tribology and Lubricants
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• 제24권3호
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• pp.147-153
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• 2008

The effect of oil supply pressure on the performance of vapor cavitated short squeeze film dampers is examined. Vapor cavitation is characterized by film rupture occurring as a result of evaporating oils. The pressure of vapor cavity in the film is almost zero in absolute pressure and nearly constant. Pan's model about the shape of vapor cavity is utilized for studying the effect of vapor cavitation on the damping capability of a short squeeze film damper. As the level of oil supply pressure is increasing, vapor cavitation is suppressed so that the direct damping coefficient increases and the cross coupled damping coefficient decreases. Futhermore, the analysis of the unbalance responses of a rigid rotor supported on cavitated squeeze film dampers shows that a significant reduction in rotor amplitude and force transmissibility is possible by controlling the oil supply pressure into short squeeze film dampers.

• 소성∙가공
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• 제12권8호
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• pp.702-709
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• 2003

In the automotive industry hydroforming of sheet metal pairs have received special attention because materials for various sheet metal components of vehicles have changed into the high strength steel, aluminum, and titanium blank having low formability. Uniform deformation over the whole region is a main advantage in the sheet hydroforming process. Because upper and lower parts could be produced simultaneously with one tool, hydroforming of sheet metal pairs is competitive in reducing the lead-time and development cost. In this paper, the multi-stage hydroforming process of sheet pair is proposed in order to increase the formability of a structural part like the oil pan shape. The upper die for forming oil pan shape is divided into two parts which can move separately. By the finite element simulation, the design parameters such as geometry of the tool and detailed specification of hydraulic pump were calculated and verified. For the strict comparison of the proposed process, the blank holding force is kept to a constant value during deformation by hydraulic valve. The deformed shape and strain distribution of the manufactured parts with the proposed process are compared with the results of simulation. In the multi-stage hydroforming process, maximum thickness strain was improved by more than 30 percent.