• 한국정밀공학회지
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• 제22권1호
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• pp.137-142
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• 2005

Gas-Assisted Injection Molding(GAIM) is an innovative technology for producing plastic parts and has been received extensive attention in the plastic manufacturing industries. But, due to gas-polymer interacting during the gas injection phase, the process has significantly different characteristics from conventional injection molding and, therefore, the control of the process requires much technical knowledge in processing and materials. The experiment was performed about variations of gas-penetration length that is affected by filling imbalance resulting from the structure of runner. The Taguchi method was used for the design of experiment. The most effective factors for the gas-penetration length were the shot size and mold temperature. The most effective factors for the difference of the gas-penetration length were the melt temperature and shot size. This study also discussed the filling imbalance phenomenon in a unary branch runner type mold that has geometrically balanced runner.

• 생물환경조절학회지
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• 제29권3호
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• pp.231-238
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• 2020

딸기는 다년생 초본성 식물로 그 과실은 영양 가치가 높고 인기있는 고부가가치 채소작물이다. 본 연구는 딸기 품종 '설향'과 '매향'의 런너유인각도(RTA)가 절간장과 런너 발생수에 미치는 영향을 조사하여 자묘의 생산성을 높이고 번식효율을 증가시키기 위한 기초 자료를 얻고자 수행되었다. 러너를 0°(상향), 45°, 90°(수평), 135°, 또는 180°(하향)의 각도로 한 달 간 유인하였다. 이 실험은 유리온실에서 주간/야간 온도 29/20℃, 평균 광도 450 μmol m^-2·s^-1 PPFD의 자연광 환경에서 수행하였으며, 1일 광주기는 12시간이었다. '설향'과 '매향'에 있어서 RTA는 런너 수와 절간장에 영향을 주었으며, 자묘 수, 생체중과 건물중에 영향을 미쳤다. RTA 135° 또는 180°에서 두 품종 모두 자묘의 평균 생체중과 건물중이 가장 작았으며, '설향' 품종에서는 런너 길이와 절간장이 짧아졌다. RTA가 두 품종 모두에서 런너의 직경에는 영향을 미치지 않았지만 런너의 형태에는 영향을 미쳤다. RTA중 135°와 비교해서 180°가 가장 많은 자묘를 생산하여 가장 번식효율이 좋았다.

• 한국자동차공학회논문집
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• 제18권5호
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• pp.62-67
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• 2010

Exhausting fossil fuel and increasing concern of air pollution have brought on the change of the focus of developing new vehicles from performance to fuel economy and emission. The gasoline engines adopting the naturally aspirated way use the throttle-body for engine load control. Therefore, its pumping loss increases more than that of the diesel engine, and also mostly operating in a partial load condition has bad influence on fuel economy and emission. In these days, the continuous variable valve timing system and variable induction system are adopted in order to improve fuel consumption and emission. In this study, we optimize the runner length and operate region of variable induction system to simulataneously improve the performance, fuel economy, and emission of gasoline engine with employing GT-Power as a CAE tool for engine analysis and PIAnO as PIDO tool for process integration and design optimization.

• 한국정밀공학회지
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• 제30권3호
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• pp.317-323
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• 2013

In-mold coating is a reactive fluid designed to improve the surface quality of injection molded thermoplastic substrate in functional and cosmetic properties. In this study, a mixing head for in-mold coating was designed, and mixing characteristics of two-component polyurethane flowing through runner were investigated based on flow simulations. In order to achieve uniform mixing of two components injected through straight mixing head, an impingement aftermixer was used in runner design. Semi-circular cross-section was better than circular one for runners for uniform mixing. With increasing runner length and flow rate, mixing became more uniform. In addition, the degree of mixing was more improved with decreasing viscosity of isocyanate.

• 한국생산제조학회지
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• 제8권6호
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• pp.64-70
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• 1999

Family injection molding of plastic is widely used to enhance productivity. Runners for molded products in fami-ly injection molding have to be balanced so that each of the producs is filled completely at the same time,. In this study computer simulations were performed to determine balanced circular section runners in family injection molding with two cavities where each of he cavity shapes is like a case. It was found from the computer simula-tions that runner balance could be fulfilled only by modifying runner diameters. But in order to get more quality molded products other process factors such as flow length flow resistance shapes of products and etc, should be taken in to consideration for the design of a family injection molding process.

• International Journal of Advanced Culture Technology
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• 제3권1호
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• pp.1-12
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• 2015

The current scenario of the transportation sector reflects the urgent need to address issues such as depletion of traditional fuel reserves and ever growing pollution levels. Researchers around the world are focussing on alternatives as well as optimisation of currently employed devices to reduce the pollution levels generated by the commonly used fuels. One such optimisation involves the study of air flow within the intake manifolds of SI engines. It is a well-known fact that alterations in the air manifolds of engines have a significant impact on the engine performance parameters, fuel consumption and emission levels. Previous works have demonstrated the impacts of runner lengths, diameter, plenum volume, taper angle of distribution manifolds and other factors on in-cylinder fluid motion and engine performance. However, a static setup provides an optimal configuration only at a specific engine speed. This paper aims to investigate the variations in the same parameters on a four stroke, naturally aspirated single cylinder SI engine through varying the cross section design over the intake runner with the aid of Computational Fluid Dynamics. The system consists of segments that form the intake runner with projections on the inside that allow various permutations of the intake runner segments. The various configurations provide the optimised fluid flow characteristics within the intake manifold at specific engine speed intervals. The variations such as turbulence, air fuel mixing are analysed using the three dimensional CFD software FLUENT. The results can be used further for developing an automated or manually adjustable intake manifold.

• 한국정밀공학회지
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• 제24권2호
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• pp.41-46
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• 2007

Recently, the study for filling imbalance in thermoplastic polymer has gradually been increased. However, it is hard to find the researches for filling imbalance of thermoplastic elastomer(TPE). The experiment of filling imbalance was conducted for the three kinds of thermoplastic vulcanizes(TPVs) in the mold with geometrically balanced runner system. In this experiment, the effects of the melt temperature and injection speed on the filling imbalance were investigated. To solve the filling imbalance, Runner Core pin(RC pin) in the experimental mold was adopted and it's effects was tested. In this paper, we present that the insert length of RC pin is dependent to each polymers for optimal filling balance.

• 한국환경과학회지
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• 제25권1호
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• pp.147-153
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• 2016

To investigate the impact of the number of runners developed from daughter plants during seedling on sapling growth and development during phase of first cluster, we examined four treatment groups that had 3-4, 5-6, 7-8, and 9-10 runners. As of June $5^{th}$, the group with 9-10 runners showed the highest number of saplings with more than 2 leaves, followed by groups with 7-8, 5-6, and 3-4 runners. Although observation on June $25^{th}$ and July $15^{th}$ showed a similar tendency for sapling numbers, no significant difference was detected between groups with 7-8 and 9-10 runners. The length of runners in the treated groups was similar to that in groups with 3-4 and 5-6 runners, with lengths of 49.4 mm and 48.0 mm, respectively, but runner length was significantly shorter in the group with 7-8 runners. Both the thickness and the weight of runners were highest in the group with 3-4 runners. The growth and development of daughter plants and root weight were similar between the groups with 3-4 and 5-6 runners, whereas both values were lower in groups with 7-8 and 9-10 runners. While stem crown thickness values were 8-7 mm and 8.5 mm in groups with 3-4 and 5-6 runners, respectively, groups with 7-8 and 9-10 runners had thinner stems of 7.1 mm and 6.2 mm, respectively. The fresh weight of saplings decreased as the number of runners increased. From the phase first cluster, leaf area and fresh weight were remarkably low in groups with 7-8 and 9-10 runners. Taken together, these results can be used to increase the production of high-quality saplings by providing a foundation for studies to investigate the impact of the number of runners developed from daughter plants on growth and development during the seedling period and the phase first cluster.

• 한국작물학회지
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• 제18권
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• pp.124-155
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• 1975

땅콩 품종육성의 기초자료와 환경에 대한 변이를 추구하고저 1968년 국내외에서 수집한 489품종을 작물시험장 시험포장에 파종하여 품종군분류를 시도하였으며 1969년에 이들 주요품종군별로 파종기를 4월 16일부터 7월 7일까지 5회 20일간격으로 5회 파종하여 품종군별 파종기에 따른 주요형질의 변이를 조사한바 그 결과를 요약하면 다음과 같다. 1. 땅콩의 분류는 초형을 주로 하고, 종실의 대소, 개화의 조만, 맥당종실수등을 기준으로 Spanish, Virginia Erect, Virginia Runner, Southeast Runner, Valencia, Semirunnerdm 6개군으로 구분하였다. 2. 품종군별 특징은 다음과 같다. (1) Spanish; 직립, 대립, 만생. (2) Virginia Erect; 직립, 대립, 만생. (3) Virginia Runner; 포복, 대립, 만생. (4) Southeast Runner; 포복, 소립, 조생. (5) Valencia; 직립, 소립, 조생, 맥당 3∼4위. (6) Semirunner; 반립, 대립, 만생. 3. 품종군별 개화일수는 파종기가 지연됨에 따라 전반적으로 단축되었으며 단축정도는 만생군에서 컸다. 4. 분기수는 각파종군 모두 만파일수록 감소하는 경향이나 Spanish와 Virginia Runner는 제1파종기에서 오히려 제2파종기보다 적었으며 각 파종기 모두 Spanish가 가장 적고 Virginia Erect가 가장 많았다. 5. 맥실비율은 각품종군 모두 5월 이후의 파종에서 현저히 감소되었으며 어느 파종기에서나 Spanish와 Southeast Runner가 높았다. 6. 맥당종실수는 어느 품종군에서나 파종기가 늦어짐에 따라 현저히 감소되었으며 소립종군보다는 대립종군에서 맥당종실수가 적었다. 7. 개체당맥실중은 각파종기 모두 제2파종기가 가장 무거웠고 제1파종기도 이보다 가벼웠으며 제2파종기이후의 파종에서는 급격히 감소하였고 각파종기 모두 Southeast Runner가 가장 무겁고 Virginia Runner가 가장 가벼웠다. 8. 개체당종실수는 개체당맥실중과 같은 경향이나 각파종기 모두 대립중에서 적고 소립종에서 많았다. 9. 100립중도 제2파종기이후의 감소는 현저하였으며 제1파종기에서도 제2파종기보다 떨어지는 경향이었다. 10. 10a당 수량에 있어서는 각품종군별 파종기에 따른 변이가 현저하였으며 제2파종기인 5월 7일에서 가장 높고, 기타 파종기에서는 감소정도가 현저하였다. 11. 주경장 분지장에 있어서 Spanish는 제1파종기에서 제2파종기보다 작았으며 기타군은 양파종기간에 비슷하였으나 그 이후 파종기에서는 급격히 감소하였다. 12. 수량과 주요형질의 상관에서 개체당맥수, 100립중, 개체당종실수등이 Virginia Runner이외의 품종군에서 수량과 높은 정의 상관이 있었으며 기타형질의 상관은거의 인정할 수 없었으며 파종기에 따른 상관의 차이가 인정되었다.13. 경로계수 분석에 의한 수량에 대한 직접효과는 모든 품종군별 파종기에서 개체당종실수, 개체당맥중 및 100립중에서 컸으며 기타는 미미하였다. 14. 품종군별 유전력은 전체적으로 개체당맥수, 맥실비율, 100립중, 개체당종실수에서 높았으며 기타가 낮았다.

• 한국운동역학회지
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• 제29권3호
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• pp.173-183
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• 2019

Objective: The aim of this study was to investigate the correlation coefficients between anthropometric parameters of the foot and kinetic variables during running. Method: This study was conducted on 21 healthy young adults (age: $24.8{\pm}2.1yes$, height: $177.2{\pm}5.8cm$, body mass: $73.3{\pm}7.3kg$, foot length: $256.5{\pm}12.3mm$) with normal foot type and heel strike running. To measure the anthropometric parameters, radiographs were taken on the frontal and sagittal planes, and determined the length and width of each segment and the navicular height. Barefoot running was performed at a preferred velocity ($3.0{\pm}0.2m/s$) and a fixed velocity (4.0 m/s) on treadmill (Bertec, USA) in order to measure the kinetic variables. The vertical impact peak force, the vertical active peak force, the braking peak force, the propulsion peak force, the vertical force at mid-stance (vertical ground reaction when the foot is fully landed in mid-stance or at the point where the weight was uniformly distributed on the foot) and the impact loading rate were calculated. Pearson's correlation coefficient was used to investigate the relationship between anthropometric variables and kinetical variables. The significance level was set to ${\alpha}=.05$. Results: At the preferred velocity running, the runner with longer forefoot had lower active force (r=-.448, p=.041) than the runner with short forefoot. At the fixed velocity, as the navicular height increases, the vertical force at full landing moment increases (r= .671, p= .001) and as the rearfoot length increases, the impact loading rate decreases (r=- .469, p= .032). Conclusion: There was a statistically significant difference in the length of fore-foot and rearfoot, and navicular height. Therefore it was conclude that anthropometric properties need to be considered in the foot study. It was expected that the relationship between anthropometric parameters and kinetical variables of foot during running can be used as scientific criteria and data in various fields including performance, injury and equipment development.