• 한국지하수토양환경학회지:지하수토양환경
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• 제13권1호
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• pp.60-66
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• 2008

본 연구에서는 실제 납 탄알로 오염된 사격장 토양에 대해 토양세척기법을 적용하기위한 lab-scale 실험을 수행하였으며 다음과 같은 결론을 얻을 수 있었다. 토양오염공정시험법과 EPA Method 3050B 분석결과 각각 4,803.5 mg/kg, 9,443 mg/kg으로 나타났다. 회분식 토양세척 실험에서 HCl을 세척제로 사용한 경우 농도증가에 따른 제거율은 로그적인(logarithmic) 경향을 나타내었고 0.1M에서 약 90% 정도 제거되었으며, EDTA는 농도에 비례하여 제거율도 증가하여 0.1 M에서 약 98%의 제거율을 보였다. 교반강도에 따른 시간별 세척효율을 분석한 결과, HCl과 EDTA를 사용한 경우 모두 교반강도의 증가와 비례하여 토양내 제거율이 증가하였으나 200 rpm과 300 rpm에서의 제거율은 유사한 것으로 나타났으며, 반응 초기 10분 이내에 대부분의 용출이 이뤄지고 60분 경과 후에는 제거율 증가가 둔화되었다.

• 대한산업공학회지
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• 제42권3호
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• pp.165-172
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• 2016

The purpose of this study is to investigate the ergonomic verification of suitability of the 4-wheeled hand cart to prevent musculoskeletal problems in the firing test range. Because of the increasing amount of firing test, the needs to develop a projectile transferring device such as 4-wheeled hand cart has been increased. For the 4-wheeled hand cart, the lifting and carrying activity in the manual handling method were transformed to pushing activity. The risk of low back pain for lifting and carrying the projectile by manual was estimated by NLE and 3D SSPP. On the other hand, the risk for pushing the 4-wheeled hand cart was estimated by psychophysical and biomechanical method such as Mital's equation, Snook's table and 3D SSPP. It was shown that the 4-wheeled hand cart reduced the risk of low back pain drastically with higher efficiency and design compatibility.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.1732-1735
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• 2003

In this paper, a DSP-based test apparatus for Control Rod Drive Mechanism (CRDM) that is used in nuclear power plants is described. Using this apparatus, we can test the mechanical and electrical characteristics of CRDM and obtain some information about how to improve the CRDM further and how to design a power controller to actuate the CRDM. Since firing angles can be directly applied to the gate-drive circuits of thyristors in the power controller by using this apparatus, the maximum and minimum values of firing angles within available limits are easily measured. Also step-current inputs help us investigate each coil's response characteristics. Therefore, we can easily find the range of control gains which enables a stable CRDM operation in insertion and withdrawal actions at high speed, mid speed, and low speed. Since this apparatus has a test mode in which an insertion or withdrawal action is divided into several phases so that the current command for each phase is given step by step, we may judge whether the CRDM works as expected or not. We also describe a fault detection capability of the test apparatus for the power controller by using discrete Fourier transform.

• 시스템엔지니어링학술지
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• 제19권1호
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• pp.107-113
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• 2023

For one-shot systems such as 81mm high-explosive ammunition, research on performance prediction is insignificant due to research manpower infrastructure and lack of interest and difficulties in securing field data, which can only be done by special task workers. In order to evaluate the actual range of ammunition, the storage ammunition reliability evaluation checks the range by firing actual ammunition through a functional test. Test evaluation is a method of extracting a sample from the population, launching it, and recording the results accordingly. As a result of these tests, the range, which is an indicator of ammunition performance, can be measured differently according to meteorological factors such as temperature, atmospheric pressure, and humidity according to the location of the test site. In this study, various environmental factors generated at the test site and storage period analyze the correlation with the range, which is the performance of ammunition, and analyze the priority of importance for each factor and the numerical standards that environmental factors affect range. Through this, a new approach to one-shot system performance prediction was presented.

• 한국군사과학기술학회지
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• 제26권2호
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• pp.139-148
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• 2023

Safety standards for long-range artillery ammunition test and training sites follow the US artillery shooting range safety zone standards. Although the South Korean geographical conditions of shooting ranges are different from those of the United States, there is no safety standard reflecting the South Korean topographical characteristics. Probable error associated with the shooting range, trajectory should be considered in establishing the safety standards. In this study, we present the safety standards for the ammunition testing site suitable for the Korean situation, with applying a concept of trajectory and probable error differed by ammunition type, which are currently confirmed by the South Korean Army's artillery shooting.

• 한국추진공학회지
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• 제25권6호
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• pp.45-52
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• 2021

본 연구에서는 액체 추진제 소형로켓엔진의 개발을 위한 선행연구로 연료과농 조건의 기체메탄-기체산소 연소시험 결과를 제시한다. 다양한 당량비에 대한 연소특성을 비교하기 위해 산소 공급 유량을 12 g/s로 설정하고 메탄 공급 유량을 변화시켰다. 시험 결과, 연소시험 중 형성되는 정상상태 특성속도가 후반에서 급작스럽게 증가하는 현상이 관측되었으며, 그 변화량은 당량비에 비례하여 커지는 경향을 확인할 수 있었다. 이를 바탕으로 특성속도의 변이특성에 종속하는 당량비 구간을 총 3가지 연소 범주로 구분하였다.

• 한국산학기술학회논문지
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• 제20권8호
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• pp.156-163
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• 2019

본 논문은 탄약의 시험 평가를 위한 탄약 운반 시스템의 개발에 관한 연구이다. 국내 탄약 시험장에서 탄약 시험 평가를 수행할 때 탄약 장전 등의 대부분 시험 평가 과정이 시험원에 의해 수행되고 있다. 즉, 탄약의 성능을 평가하기 위해 수십 kg 무게가 나가는 탄약의 이송 및 장전, 사격의 과정이 시험원에 의해 반복적으로 이뤄진다. 이 과정에서 탄약 장전 작업의 경우 인력에 의한 작업은 시험 결과의 신뢰성 저하, 시험원의 근골격계 손상, 안전사고와 같은 문제들이 발생할 소지가 있다. 이러한 문제점들을 해소하기 위해 시험용 탄약의 안전한 이송, 자동 장전 등의 운용성 향상을 위한 탄약 운반 시스템을 개발하였다. 이 논문은 운반 시스템의 설계, 제조, 그리고 운영의 효용성 등을 다루고 있다. 또한 사람에 의한 운용과 비교하여 개발된 시스템의 효용성 평가를 수행하였다. 본 연구 결과는 국내 탄약 시험장에서 안전한 시험 평가를 위해 활용될 수 있을 것이다.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2010년도 제35회 추계학술대회논문집
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• pp.135-140
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• 2010

The high specific impulse of the ramjet engine, combined with the ability of a gel to carry metal particles, make the Gel Fuel Ramjet a most adequate solution for a mid-high range sustainer. The goal of the present study is to verify experimentally the feasibility of such a concept. A test facility and a lab-scale motor have been designed and built to investigate atomization, ignition and firing processes of a gel hydrocarbon fuel, with and without metal additives, as well as to check the ramjet operation as a whole. The present paper presents the experimental system in detail as well as qualitative results of a few firing tests.

• International Journal of Aerospace System Engineering
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• 제9권1호
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• pp.1-15
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• 2022

Pyrotechnic initiators provide a source of pyrotechnic energy used to initiate a variety of space mechanisms. Pyrotechnic systems build in electromagnetic environment that may lead to critical or catastrophic hazards. Special precautions are need to prevent a pulse large enough to trigger the initiator from appearing in the pyrotechnic firing circuits at any but the desired time. The EMC verification shall be shown by analysis or test that the pyrotechnic systems meets the requirements of inadvertent activation. The MIL-STD-1576 and two range safeties, AFSPC and CSG, require the safety margin for electromagnetic potential hazards to pyrotechnic systems to a level at least 20 dB below the maximum no-fire power of the EED. The PC23 is equivalent to NASA standard initiator and the 1EPWH100 squib is ESA standard initiator. This paper verifies the two safety margins for electromagnetic potential hazards. The first is verified by analyzing against a RF power. The second is verified by testing against a DC current. The EMC safety margin requirement against RF power has been demonstrated through the electric field coupling analysis in differential mode with 21 dB both PC23 and 1EPWH100, and in common mode with 58 dB for PC23 and 48 dB for 1EPWH100 against the maximum no-fire power of the EED. Also, the EMC safety margin requirement against DC current has been demonstrated through the electrical isolation test for the pyrotechnic firing circuits with greater than 20 dB below the maximum no-fire current of the EED.

• The Journal of Advanced Prosthodontics
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• 제12권3호
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• pp.167-172
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• 2020

PURPOSE. The aim of the present study was to investigate the passive fit of metal substructure after repetitive firing processes in implant-supposed prosthesis. MATERIALS AND METHODS. Five implants (4 mm diameter and 10 mm length) were placed into the resin-based mandibular model and 1-piece of screw-retained metal substructure was produced with the direct metal laser sintering (DMSL) method using Co-Cr compound (n = 10). The distance between the marked points on the multiunit supports and the marginal end of the substructure was measured using a scanning electron microscope (SEM) at each stage (metal, opaque, dentin, and glaze). 15 measurements were taken from each prosthesis, and 150 measurements from 10 samples were obtained. In total, 600 measurements were carried out at 4 stages. One-way ANOVA test was used for statistical evaluation of the data. RESULTS. When the obtained marginal range values were examined, differences between groups were found to be statistically significant (P<.001). The lowest values were found in the metal stage (172.4 ± 76.5 ㎛) and the highest values (238.03 ± 118.92 ㎛) were determined after glaze application. When the interval values for groups are compared with pairs, the differences between metal with dentin, metal with glaze, opaque with dentin, opaque with glaze, and dentin with glaze were found to be significant (P<.05), whereas the difference between opaque with metal was found to be insignificant (P=.992). CONCLUSION. Passive fit of 1-piece designed implant-retained fixed prosthesis that is supported by multiple implants is negatively affected by repetitive firing processes.