• 품질경영학회지
• /
• 제46권3호
• /
• pp.425-440
• /
• 2018

Purpose: This study is aimed at developing of the flex resistance testing process at low temperature with the waterproof fabric to suit the military environment, and is designed to fit for the purpose of the waterproof materials in order to optimize the test method by finding out matters to improve from existing the test method and through previous studies. Methods: The test method, which has been applied to flex resistance of existing water-repellent materials, was improved and consequently, differentiated test results could be obtained according to the test temperature, sample size, and flexing method. Results: The testing of the total of 8 samples revealed that performance of the military requirement could hardly be met just by presenting the materials or 2~3 layers when the quality criteria for high functional water repellent fabrics were applied. PTFE(Polytetrafluoroethylene) is preferred to PU(Polyurethane) to be used in the extremely low-temperature environment, but durability under the low-temperature environment may be varied depending on film thickness or laminating technique even if the materials of waterproof films are identical. Therefore, in addition to the material or texture, the test method capable of reflecting durability under the low-temperature environment shall be suggested, and the newly designed test method proposed in this study was shown to suggest differentiated quality criteria by the material. Conclusion: The water resistance measurement and the test method following flex resistance with expanded range of flex will enable the differentiable test of the samples according to the number of repetition. This study is meaningful in that it suggests a differentiable test method capable of establishing a basis of deciding suitable material when selecting military goods made of water repellent material by properly improving the test method.

• 대한기계학회논문집A
• /
• 제39권12호
• /
• pp.1275-1280
• /
• 2015

카운터웨이트를 수명시험 하기 위해서는 실제 현장과 유사하게 2 톤의 무게를 가진시켜 주는 대형 가진기가 필수적이다. 그렇지만 이러한 장비를 일반업체에서 보유하여 시험하기는 어려우므로, 이러한 애로점을 해소하기 위해 본 연구에서는 첫번째로 2 톤의 중량물일지라도 건설기계의 신뢰성을 평가하는 전기터들로 구성되는 회전식 가진기를 사하여 실제 현장조건을 재현하는 시험장비를 개발하였고, 주요 구성품에 대해 카운터웨이트의 고장해석을 수행하였다. 두번째로 현장으로부터 필드데이터를 측정하여 수명시험에 활할 수 있도록 하였다. 마지막으로 성능과 수명을 확인하기 위해 가속수명시험법을 개발하였고, 제품의 고장발생 없이 $B_5$ 10,000 시간을 만족하는 가속수명시험을 완료하였다.

• International Journal of Fluid Machinery and Systems
• /
• 제10권1호
• /
• pp.40-46
• /
• 2017

Small valves including ball valves, gate valves and butterfly valves have been adopted in the fields of steam power generation, petrochemical industry, carriers, and oil tankers. Butterfly valves have normally been applied to fields where in narrow places installing the existing valves such as gate valves and ball valves have proven difficult due to the surrounding area and the heavier of these valves. Butterfly valves are used to control the mass flow of the piping system under low pressure by rotating the circular disk installed inside. The butterfly valve is benefitted by having simpler structure in which the flow is controlled by rotating the disc circular plate along the center axis, whereas the weight of the valve is light compared to the gate valve and ball valve above-mentioned, as there is no additional bracket supporting the valve body. The manufacturing company needs to acquire the performance and life test equipment, in the case of adopting the improving factors to detect leakage and damage on the seat of the valve disc. However, small companies, which are manufacturing the industrial valves, normally sell their products without the life test, which is the reliability test and environment test, because of financial and manpower problems. Furthermore, the failure mode analysis of the products failed in the field is likewise problematic as there is no system collecting the failure data on sites for analyzing the failures of valves. The analyzing and researching process is not arranged systematically because of the financial problem. Therefore this study firstly tried to obtain information about the failure data from the sites, analyzed the failure mode based on the field data collected from the customers, and then obtained field data using measuring equipment. Secondly, we designed and manufactured the performance and life test equipment which also have the real time monitoring system with the naked eye for the butterfly valves. The concept of this equipment can also be adopted by other valves, such as the ball valve, gate valve, and various others. It can be applied to variously sized valves, ranging from 25 mm to large sized valves exceeding 3000 mm. Finally, this study carries out the life test with square wave pressure, using performance and life test equipment. The performance found out that the failures from the real time monitoring system were good. The results of this study can be expanded to the other valves like ball valves, gate valves, and control valves to find out the failure mode using the real time monitoring system for durability and performance tests.

• 한국항행학회논문지
• /
• 제22권6호
• /
• pp.530-536
• /
• 2018

최근 무인항공기 드론의 활용범위와 수요가 지속적으로 증가함에 따라 무인항공기와 유인항공기 간 공역을 통합하여 운용하는 연구가 전 세계적으로 활발하게 진행되고 있다. 공역 통합을 위해서는 유인항공기에 준한 기술기준 및 인증 제도 수립이 필수적이며, 이에 따른 시험평가 방안이 제시되어야 한다. 본 논문에서는 향후 무인항공기 항법 시스템에 대한 기술기준이 수립되었을 경우, 기술기준 적합성 검증을 위한 시험방법을 제시하였다. 연구를 위해 무인항공기 임무 프로파일 및 운용환경 분석, 시험항목 도출, 시험방법 수립, 시뮬레이션 및 무인항공기를 통한 실증을 수행하였다. 시험방법으로 정적시험, 트랙이동시험, 경로비행시험이 도출되었으며, 각 시험수행 결과 시험대상 무인항공기의 항법시스템 오차는 전체 비행단계에서 95% 신뢰수준에서 약 1.4m의 위치정확도를 보임을 확인하였다.

• 한국산업융합학회 논문집
• /
• 제23권5호
• /
• pp.835-842
• /
• 2020

This paper considers a method of reproducing abnormal and fault operation for smart monitoring of thrust bearing used in wave power generation system. In order to develop smart monitoring technology, abnormal and failure data of actual equipment are required. However, it is impossible to artificially break down the actual equipment in operation due to safety and cost. To tackle this problem, a test bed that can secure data through reproduction of a faulty operating environment should be developed. Therefore, in this study, test bed that can reproduce each situation was developed and the operation result was analysis after identifying the situation to be reproduced through the failure factor analysis of the thrust bearing.

• 대한의용생체공학회:학술대회논문집
• /
• 대한의용생체공학회 1996년도 추계학술대회
• /
• pp.111-113
• /
• 1996

The impaired person and the elderly who has hearing loss have been continuously increased and these people's desire for participating society as a producer has been increased also. So they strongly request the aid device which can compensate their handicap. The healing aid telephone is one of the basic aid devices that helps the hearing impaired to communicate with other people and to acquire useful information. We design the new model of the hearing aid telephone and test it's efficiency in three fields - electrical, speech perception, user test. From the result of the test we certify that the new model is better for the hearing impaired to understand the meaning of telephone speech than the old general models. We expect that the advanced healing aid telephone can be developed by the research about speech perception characteristics of the hearing impaired in engineering and clinical side.

• Biomolecules & Therapeutics
• /
• 제30권4호
• /
• pp.334-339
• /
• 2022

Peroxiredoxin 6 (PRDX6) is a bifunctional protein with both glutathione peroxidase and calcium-independent phospholipase activity. Recently, we reported that PRDX6 plays an important role in dopaminergic neurodegeneration in Parkinson's disease. However, the relationship between PRDX6 function and emotional behavior remains elusive. In the present study, we examined depression- and anxiety-like behaviors in PRDX6-overexpressing transgenic (PRDX6-Tg) mice using the forced swim test, tail suspension test, open field paradigm, and elevated plus-maze. PRDX6-Tg mice exhibited depression-like behaviors and low anxiety. In particular, female PRDX6-Tg mice exhibited anxiolytic behavior in the open field test. Furthermore, the serotonin content in the cortex and 5-hydroxytryptophan-induced head twitch response were both reduced in PRDX6-Tg mice. Interestingly, levels of dopa decarboxylase expression in the cortex were decreased in male PRDX6-Tg mice but not in female mice. Our findings provide novel insights into the role of PRDX6 in 5-HT synthesis and suggest that PRDX6 overexpression can induce depression-like behaviors via downregulation of the serotonergic neuronal system.

• 한국자동차공학회논문집
• /
• 제24권1호
• /
• pp.90-98
• /
• 2016

Currently government certified test method for an automobile remanufactured products is insufficient. Thus many automotive parts in the remanufacturing market are lacking proper evaluation criteria and production of defective products are causing customer dissatisfaction. In this paper a power steering oil pump, which requires stringent manufacturing standards, is studied by the failure mode and effect analysis approach. The research suggested that the test criteria such as discharge flow characteristic test, tightness test, pulley run-out test, pressure switch operation test, low temperature test and rotation pressure durability test should be performed to evaluate the reliability of remanufactured power steering oil pumps. As a result of tests, the performance of remanufactured power steering oil pump satisfied the evaluation criteria of pressure switch operation test and low temperature test. However, the remanufactured power steering oil pump failed to satisfy the evaluation criteria on discharge performance test, tightness test and pulley run-out test. These performance evaluation tests proved the necessity of standard process for the remanufactured power steering oil pump.

• 한국자동차공학회논문집
• /
• 제14권6호
• /
• pp.184-189
• /
• 2006

Tumble flow test rig has been used as the useful tool in the developing intake system because major flow pattern induced by intake port of DOHC engine is tumble. Angular momentum of in-cylinder tumble flow can not be directly measured by impulse torque meter in the test rig like that of in-cylinder swirl flow due to rotational axis of the flow. Therefore the adaptor to transform tumble to swirl flow must be adapted in the test rig. In this study, using the commercial CFD code STAR-CD, we studied the effects on measured results due to the variation of the major design variables in the adaptor, tube length(L), tube diameter(D) and cylinder height(H). The effect of the attached angle($\theta$) of the test head to the adaptor also was simulated.

• 대한금속재료학회지
• /
• 제46권2호
• /
• pp.80-87
• /
• 2008

Many researches related to the reliability of Pb-free solder joints with PCB (printed circuit board) surface finish under thermal or vibration stresses are in progress, because the electronics is operating in hash environment. Therefore, it is necessary to assess Pb-free solder joints life with PCB surface finish under thermal and mechanical stresses. We have investigated 4-points bending fatigue lifetime of Pb-free solder joints with OSP (organic solderability preservative) and ENIG (electroless nickel and immersion gold) surface finish. To predict the bending fatigue life of Sn-3.0Ag-0.5Cu solder joints, we use the test coupons mounted 192 BGA (ball grid array) package to be added the thermal stress by conducting thermal shock test, 500, 1,000, 1,500 and 2,000 cycles, respectively. An 4-point bending test is performed in force controlling mode. It is considered that as a failure when the resistance of daisy-chain circuit of test coupons reaches more than $1,000{\Omega}$. Finally, we obtained the solder joints fatigue life with OSP and ENIG surface finish using by Weibull probability distribution.