• Journal of the Korean Society of Clothing and Textiles
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• v.41 no.5
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• pp.950-965
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• 2017

This present study proposed a newly developed test method to evaluate the dexterity and mobility of a firefighter's protective gloves. The first step evaluated the mobility and dexterity of the current type of fire protective gloves and three new types of protective gloves using Don-doff test, ASTM dexterity, Minnesota dexterity, Bennett hand tool test, and ASTM torque test. Three firefighters ($47.3{\pm}5.0yr$ in age, $178.6{\pm}2.9cm$ in height) participated in a series of experiments. The second step was to design and suggest an integrated test method based on the results of the first experiment. As a result of the first experiment, we concluded that 1) the mobility and dexterity tests for firefighting gloves should include both wet and dry tests, 2) The three kinds of dexterity tests could be integrated into one test, and 3) The don-doff test and the torque test should be independent from the newly developed integrated test. In summary, we suggested a simplified test method that combined ASTM dexterity, Minnesota dexterity, and Bennett hand tool test. The integrated system can reduce total time spent on dexterity tests and improve the validity of the test in terms of firefighters' manual work.

• Journal of Energy Engineering
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• v.24 no.4
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• pp.63-70
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• 2015

Crevices between window and window frame cause not only heat losses but also serve path to sound transmission and infiltration of fine dusts that are harmful to humans. There were many efforts in the past to eliminate these crevices but because of the windows' indispensable function of opening and closing, it was an unsolvable problem. In this study, a new type sliding window is developed by applying horizontally rolling wheels to implement a surface sealing which is excellent for enhancing air tightness. To evaluate the feasibility of the newly developed window, forces for opening and closing, durability and air tightness were testet according to Korean Testing Standards. Force for opening a 2000 N window is 30 N. It endured 100,000 cycles of opening and closing. Infiltration was $0.00m^3/(m^2h)$ for a pressure difference of 10 Pa. Since this window has few moving parts, it has favorable features of low cost and few breakdown.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.2
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• pp.121-127
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• 2017

From the perspective of commercializing rotating machines equipped with magnetic bearings, maintaining the error between the mechanical center and the magnetic center within an acceptable level is crucial. The existing method of measuring the center error is to adjust the position references that minimize the current imbalance present in levitation control outputs. However, this method can be applied only after all the components of the system are operational. In this paper, we present a new method of estimating the center error by using only the position sensors and a current source. A force model that relates the position of the rotor with the coil currents is set up. Using this model, the center error is estimated by minimizing the difference between the force angles and the contact angles measured in a pull test. The feasibility of the method is numerically and experimentally validated.

• Proceedings of the KIEE Conference
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• 2000.07a
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• pp.175-181
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• 2000

월성원자력4호기가 '99.06.09일 11:53분 경 전출력 소외전원상실시험시 주발전기 병입차단기 및 기동용변압기 차단기의 트립과 동시에 예상 밖의 13.8Kv 원자로 냉각재펌프모터#3(9.000HP)이 순시과전류 보호계전기(50Y) 동작으로 트립되어 이로 인한 냉각재 저유량으로 원자로 제1정지계통이 동작되고 원자로가 비상정지 되어 동 시험이 실패되었음. 이 비정상적인 고장은 예비디젤발전기의 수동 기동 병입과 터빈 수동 정지 및 주발전기 트립후 적절한 조치로 소내전원은 정상적으로 복구되었음. 이에 대해 냉각재펌프모터#3의 순시과전류 동작 원인을 유도전동기의 전원상실 후 발생되는 잔류전압(Residual Voltage)과 공급 모선전압(Bus Voltage) 측면에서 분석하며, 모터의 회전속도, 위상각, 잔류전압크기 변화 및 신속개방 절체시 냉각재펌프모터의 돌입 기동전류를 계산하고, PSS/E 프로그램을 사용한 간략한 모의 사례로 검증하였으며 이에 대한 재발방지를 위한 대책을 제시함.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.6
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• pp.266-274
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• 2020

This paper reports a means of improving the abnormal noise of light tactical vehicles (LTVs) by applying a vehicle fitting type generator (hereinafter called generator). LTVs are classified as having generators, and there are no differences in the noise level. On the other hand, quality improvement was performed in response to unpleasant noise felt by the user (hereinafter called abnormal noise) during vehicle operation. To improve the quality, the generator mounting structure and the phenomenon of the vehicle in the problem were identified. Through this, it was confirmed that the noise caused by the generator installation was the rattle noise. Rattle noise at the engine driving system is normally caused by the transfer of irregular torque generated by the engine power stroke and the backlash by the spline-serration fitting structure between the engine coupler and rotor assembly in a generator. Therefore, this study established an improvement plan to apply a damper coupler to solve the cause of the abnormal noise. Regarding the improved establishment method, the improvement effect was confirmed from the influence of the irregular torque of the engine, noise level, dynamic characteristics analysis, and the endurance test of the parts.

• Journal of the Korean Society of Propulsion Engineers
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• v.20 no.1
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• pp.76-81
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• 2016

At negative-g condition, a float-type valve can open the passage of fuel in order to it flows continuously through a pressurized fuel tank system. Since specialized test conditions and high-cost supports are required, it is truly difficult to test the valve in a real high-speed test. Therefore, this paper contains performance analysis of a float-type fuel supply valve through flight tests conducting roll and negative-g maneuvers.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.16 no.3
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• pp.63-68
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• 2017

In order to process more complicated and higher-precision parts, generally, an additional axis for a machine tool is needed which was an approach to minimize the cost of tool modification. A table with a rotary reducer that can rotate through the axis of the gear system was employed to a machine tool to achieve the purpose of adding an extra motion axis. In general, the motion of the rotary reducer is driven by a worm/wheel or helical gear system, which is different from the hypoid helical gear structure that used in this research. Reliability of guarantee of high accurancy throughout the whole life cycle is on of the critical factors to evaluate a rotary reducer in this field. In this paper, in order to evaluate life-time of rotary reducer, a low-cost accelerated life test was developed to satisfy the demands of clients.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.215-215
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• 2011

본 논문은 상용차용 전동 쿨링팬 모듈의 개발을 위한 5kW급 브러시리스 DC 전동기에 관하여 기술한다. 개발 대상전동기는 정격 3,000rpm의 회전속도를 목표로, 기존 팬 쉬라우드에 장착 가능한 박형으로 설계되며, 코깅토크 저감을 위한 회전자와 고정자 형상 최적화를 수행하여, 구동시 소음과 진동을 감소시키고자 하였다. 전동기를 제작하여 입출력 특성을 분석하고, 최종적으로 기 개발된 팬 블레이드와 결합하여, 쿨링팬 시스템의 유량 및 유압 특성시험을 진행하였다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.3
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• pp.463-470
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• 2016

A vane shear test (VST) is a simple testing method for determining an undrained shear strength of cohesive soils by minimizing soil disturbance. In this study, the VST was used to determine a shear strength of sand. Dry Nakdong River sand was prepared for loose and dense conditions in a cell and then pressurized with 25, 50, 75 or 100 kPa from the surface of sand. A vane (5 cm in diameter and 10 cm in height) was rotated and a torque was measured within sand. When a torque moment by vane and friction resistance moment by sand is assumed to be equalized, a friction angle can be obtained. When a vane rotates within clay, a uniform undrained shear strength is assumed to be acting on cylindrical failure surface. On the other hand, when it is applied for sand, the failure shape can be assumed to be an octagonal or square column. The relationship between measured torque and resistant force along assumed failure shapes due to friction of sand was derived and the internal friction angle of sand was determined for loose and dense conditions. For the same soil condition, a series of direct shear test was carried out and compared with VST result. The friction angle from VST was between 24-42 degrees for loose sand and 33-53 degrees for dense sand. This is similar to those of direct shear tests.

• Journal of the Korean Institute of Intelligent Systems
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• v.17 no.2
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• pp.154-159
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• 2007

Wake distribution data of stem flow fields have been accumulated systematically by model tests. If the correlation between geometrical hull information and wake distribution is grasped through the accumulated data, this correlation can be helpful to designing similar ships. In this paper, Neuro-Fuzzy system that is emerging as a new knowledge over a wide range of fields nowadays is tried to estimate the wake distribution on the propeller plan. Neuro-Fuzzy system is well known as one of prospective and representative analysis method for prediction, classification, diagnosis of real complicated world problem, and it is widely applied even in the engineering fields. For this study three-dimensional stern hull forms and nominal wake values from a model test ate structured as processing elements of input and output layer, respectively. The proposed method is proved as an useful technique in ship design by comparing measured wake distribution with predicted wake distribution.