• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2003.06a
• /
• pp.1483-1486
• /
• 2003

Injection mold is a manufacturing process used to produce the various parts of complicated shape at a low cost. Many factors such as, section shape, resin and mold temperature, filling time, etc, affect on the quality of injection part during injection molding process. The precent study, was carried out the shrinkage analysis of shoes injection mold to optimize runner shape based on filling and packing pressure with MoldFlow. Taguchi design and analysis of variance are used to optimize injection mold design.

• Journal of Advanced Marine Engineering and Technology
• /
• v.30 no.2
• /
• pp.296-303
• /
• 2006

Recently, micro hydropower attracts attention because of its clean. renewable and abundant energy resources to develop. However, suitable turbine type is not normalized yet in the range of micro hydropower and it is necessary to study for the effective turbine type. Moreover, relatively high manufacturing cost by the complex structure of the turbine is the highest barrier for developing the micro hydropower turbine. Therefore a cross-flow turbine is proposed for micro-hydropower in this study because of its simple structure and high possibility of applying to low head. The purpose of this study Is to further optimize the turbine structure and improve the performance. A guide vane is removed and the runner chamber is made compact using a new air supply method. The results show that the efficiency of the turbine is improved in a wide operating range and the size of the turbine is remarkably reduced.

• Journal of Advanced Marine Engineering and Technology
• /
• v.22 no.1
• /
• pp.85-91
• /
• 1998

In this paper, an influence of inlet pressure on the running characteristics of tilting pad thrust bearing is studied by a numerical analysis. The inlet pressure is obtained from the extended Bernoulli equation including the loss coefficient which is varied with the operating conditions. The running characteristic parameters such as the minimum film thickness, the film pressure and the film thickness ratios are calculated for various runner speeds with constant load in particular two pivot positions. The results are shown that the inlet pressure has a large influence on the minimum film thickness and other running characteristic parameters.

• Design & Manufacturing
• /
• v.1 no.1
• /
• pp.17-21
• /
• 2007

In the manufacture and processing of large plastic materials, product quality is tested and verified through several techniques such as injection processing, residual stress through injection molding and shrinkage. With regards to the injection molding process, common problems such as inconsistent density is seen when different points of the product are discovered to have varying thickness levels. Sink marks in product are then evident. This occurs when there is poor molding conditions caused about by poor runner and packaging systems incorporated into the process. We designed the runner system which is possible balanced filling to cavities using CAE program $Moldflow^{TM}$ and then obtained optimal processing conditions by Taguchi's Robust Design technique.

• Journal of Power System Engineering
• /
• v.12 no.6
• /
• pp.78-82
• /
• 2008

Plastic gears are more and more widely used in many industrial machine elements. Plastic gear has higher properties such as light weight, wear resistance, and vibration absorbing ability than metallic gears. But, in case of using an inaccurate plastic gear, its tooth breakage happen and fatigue life is shortened due to increase of applying load and temperature rising on the tooth flank. Inaccuracy of plastic gears such as pitch circle roundness and tooth profile generates vibration and noise. In this study, an internal plastic gears which is molded by a new injection mold structure are developed. The new mold structure is called the HR3P(hot runner type 3plate mold) that has an improved runner system in order to have good filling balance. As a result from this study, an internal gear with very accurate roundness was developed by using design of experiment.

• 유체기계공업학회:학술대회논문집
• /
• 2005.12a
• /
• pp.819-824
• /
• 2005

Recently, micro hydropower attracts attention because of its clean, renewable and abundant energy resources to develop. However, suitable turbine type is not normalized yet in the range of micro hydropower and it is necessary to study for the effective turbine type. Moreover, relatively high manufacturing cost by the complex structure of the turbine is the highest barrier for developing the micro hydropower turbine. Therefore, a cross-flow turbine is proposed for micro-hydropower in this study because of its simple structure and high possibility of applying to low head. The purpose of this study is to further simplify the turbine structure and improve the performance, A guide vane is removed and the runner chamber is made compact using a new air supply method. The results show that the efficiency of the turbine is improved in a wide operating range and the size of the turbine is remarkably reduced.

• International Journal of Fuzzy Logic and Intelligent Systems
• /
• v.10 no.1
• /
• pp.37-42
• /
• 2010

Final year students are normally encountering high pressing in their study. In view of this fact, this research focuses on determining mental states condition of college student in final year based on the psycho-physiological information. The experiments were conducted in two times, i.e., prior- and post- graduation seminar examination. The early results indicated that the student profile of mood states (POMS) in prior final graduation seminar showed higher scores than students in post final graduation seminar. Thus, in this research, relation between biosignal representing by heart rate variability (HRV) and questionnaire responses were evaluated by hidden Markov model (HMM) and neural networks (NN).

• Asian Journal of Turfgrass Science
• /
• v.2 no.1
• /
• pp.31-40
• /
• 1988

4가지 관수 처리 회수가 한국 잔디와 Zoysia-82에 미치는 영향을 조사한 결과는 다음과 같다. 1. 한국 잔디가 각 관수처리마다 Zoysia-82보다 엽장은 길고 엽복은 넓은 편이었다. 2. Runner의 생장은 Zoysia-82가 왕성했으며, 두 품종 공히 매일 1회 관수, 대비구(자연상태), 5일, 10일마다 1회 관수구순으로 runner의 길이가 길고 1일 생장량도 많았다. 3. 이식시 단위 spring당 각 부위별 건물량은 한국잔디가 더 무거웠으나 생육을 거듭할수록 Zoysia-82가 더 무거웠고, 1일 건물량 증가량도 Zoysia-82가 더 많았다. 4.지표면 피복율은 각 관수처리별 Zoysia-82가 한국 잔디보다 빨랐다. 두 품종 공히 매일 관수구 가장 빨랐고, 대비구, 5일, 10일마다 1회 관수구 순으로 빨랐다.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.13 no.4
• /
• pp.534-541
• /
• 2010

With the financial sponsorship of FKI and six other companies, the design and construction of the human powered aircraft Sky Runner has been begun to design in December of 2008. And it flew in late December of 2009. The original design configuration was continuously modified in response to test results as a 30.36m span, $35.25m^2$ wing area, 26.0 aspect ratio and 39.8kg of empty weight. Although, we have made only 150m flight flying a few seconds so far however, it will contribute to the research of ultra-light and long duration flying planes. A brief review of some design features, wing layout, prop design, fabrication and flight test results are presented.

• Journal of Power System Engineering
• /
• v.9 no.3
• /
• pp.39-43
• /
• 2005

Among many other alternative energy resources, small scale hydropower has been brought into attention as a reliable source of energy today, which had been relatively neglected since 1960s. Present low head of Francis turbines and small scale hydroturbines, however, have limitations in the minimum required head and flow rate for efficient operation. This study attempts to develope the Francis turbine which is expected to run efficiently even in very low head and small flow rate, so that the limitations on the conventional small scale hydropower could alleviated and competition with other alternative energy sources in the changable design conditions could attained. The Francis turbine of a new concept was designed based on changable design conditions, hydrodynamics and theory of power transmission. The result of the study shows that two stages runner is more efficient, cheaper in construction, faster responding, and easier maintaining than single stage runner of Francis turbine