This study was conducted to compare the mechanical properties of NAB (Ni-Al-Bronze) material manufactured using WAAM (wire arc additive manufacturing) technology and cast NAB that has been used. Two types of mechanical property test pieces were collected from the deposited bulk NAB material according to the direction of deposition, and compared with each other. As a result of mechanical property evaluation, the deposited NAB exhibited anisotropy according to the direction of deposition, and showed high tensile strength, hardness, and shock absorption in the longitudinal direction of the welding line.

VOCs는 인체에 치명적인 질환을 유발하는 물질로써 도장공정중 발생되는 양이 가장 큰 비 중을 차지하고 있다. 일반적으로 소형 도장시설에서 발생되는 VOCs를 처리하는 방법으로 활성탄 흡착 또는 흡착 후 연소 및 촉매 산화법 등을 사용하고 있다. 하지만 활성탄 교체주기, 재생시설 및 재생주기 등을 예측하기 어려워 새로운 처리방법이 필요하다. 비이송식 플라즈마 시스템을 이용한 VOCs 제거방 법은 일반 연소과정이 아닌 고전압 아크 방전에 의한 고온 플라즈마 유동 발생 기술을 이용한 제거방법 으로 화학반응이나 오염이 없는 고순도의 고온 열처리 및 열분해가 가능하다. 본 연구에서는 고온 아크 플라즈마 시스템을 이용하여 특수 환경오염물 및 VOCs 가스 열처리 공정의 핵심기술로 활용하여 작동 가스 유량 변화에 따른 VOCs 처리 효율 및 플라즈마 전력량에 따른 처리 효율을 측정하였다. 또한 유 해가스 처리효율성 증대를 위해 플라즈마 반응기를 최적화하여 제작하였으며 성능을 파악하였다.

The purpose of this study is to research into which characteristic is shown according to a change in filler metal in case of CO2 gas arc welding by using Automobile Structural Steel(ATOS80). The major characteristics of this study were experimented by having Bevel angle as 50°, Root gap as 3mm, Filler metal as Solid wire & Flux wire, and the projected length of wire as 15mm. This study made the welded test specimens for the KS specification in advance suitably for the conditions, thereby having comparatively analyzed with the data value that was obtained through tensile test, hardness test, impact test and Macro Structure Detecting. Arranging the results that analyzed finally, the tensile strength and the hardness appeared to be excellent in case of welding with flux wire. The impact strength was indicated to be superior in case of welding with solid wire.

최신의 방사선치료 기법 중의 하나인 체적변조회전치료의 경우 치료 시 방사선은 회전하면서 연속조사를 실시하는 반면 치료계획상에서는 1도 간격의 고정조사형태로 계획되게 된다. 이에 본 연구에서는 체적변조회전치료계획의 정확성을 평가하고자 하 였다. 연속조사에 대한 치료계획이 불가능하므로 3구간에 대해 0.2도 간격, 0.5도 간격, 1.0도 간격, 2.0도 간격으로 치료계획을 실시하여 6개의 용적에 대해 처방선량의 50% 와 70% 용적에 대한 V50과 V70의 평가지표를 비교하였다. 그리고 평가지표 별 용적 에 대한 선속간격 그래프를 통해 연속조사에 대한 값을 외삽하여 추정하였다. 그리고 외삽된 연속조사의 값과 1도간격인 치료계획의 값을 비교하여 오차값을 획득하였다. 그 결과 V50에서는 최대 9.46%의 차이를 보였으며, V70의 경우 최대 25%의 차이를 보였다. 이를 통해 체적변조회전치료계획의 경우 선량의 부정확성을 인지하면서 치료 계획을 실시하여야 하며, 치료계획 컴퓨터의 개발 시 1도 간격이 아닌 본 연구의 결과 에서 처럼 0.5도 간격으로 재설정하여야 할 것이다. 물론, 간격이 좁아지면 계산속도가 느려지므로, 2단계에 걸쳐 계산하는 시스템의 도입도 고려해보아야 할 것이다.해야 할 것이다.

The microstructures and cyclic voltammograms of Al-Si/C nano-composites were investigated as the anode of lithium ion batteries. Al-Si nanoparticles were prepared by the arc-discharge method. Al-Si/C nanoparticles were obtained by coated Al-Si nanoparticles with the precursor of glucose (C6H12O6) as carbon source. It was indicated that the post carbon coating treatment can reduce Al2O3 film on Al-Si particles, and new phase Al4C3 formed in the process can activate the inactivated materials of electrode in a certain extent.

The properties of dust collected from electric arc furnace of ferro manganese production units was investigated, and also the metallic manganese was recovered from the dust by aluminothermy process. The ferromanganese dust collected from electric arc furnace contained about 15% of manganese oxide (Mn3O4) and 9% of carbon as the contaminant, and have a 5um of 50% median diameter and irregular particle shape. The carbon contaminant in the dust could be reduced until about 0.1~0.5% level by roasting in the air at a temperature of 600~900C for 60minutes. The recovery of manganese could not be carried out using only ferromanganese dust from electric arc furnace by aluminothermy process, but the ferromanganese which contained manganese of about 92% and iron of about 5% could be obtained from the mixture of ferromanganese dusts from electric arc furnace and converter. The best mixing condition of dust fixed at electric arc furnace dust / converter dust ratio of 1:9 and 2:8, and the mixing rato of 3:7 or more could not separated the metal and slag from the reactant after aluminothermy reaction.

PURPOSES: This paper, presents the results of a laboratory study aimed to verify the suitability of a particular type of Electric Arc Furnace (EAF) steel slag to be recycled in the lithic skeleton of both dense graded and porous asphalt mixtures for flexible pavements. METHODS : Cyclic creep and stiffness modulus tests were performed to evaluate the mechanical performance of three different asphalt mixtures (dense graded, porous asphalt, and stone mastic) prepared with two types of EAF steel slag. For comparison purposes, the same three mixtures were also designed with conventional aggregates (basalt and limestone). RESULTS : All the asphalt mixtures prepared with EAF steel slag satisfied the current requirements of the European standards, which support EAF steel slag as a suitable material for flexible pavement construction. CONCLUSIONS : Based on the experimental work, the use of waste material obtained from steel production (e.g. EAF steel slag) as an alternative in the lithic skeleton of asphalt mixtures can be a satisfactory and reasonable choice that fulfills the “Zero Waste”objective that many iron and steel industries have pursued in the past decades.

The potential of marginal materials as components of road infrastructures has been studied for many years. The list of materials includes non-traditional natural materials (rocks and soils), industrial by-products (from metallurgical industry, thermal electric power stations, and chemical industry) and wastes (mining and quarrying, municipal, industrial and demolition wastes). Among these materials, Electric Arc Furnace Steel Slags (EAFSS) presents physical-mechanical characteristics and full chemical compatibility with the hydrocarbon binders used in road construction and, therefore, have high potential for being re-used. This paper presents the results of a laboratory study conducted to verify the suitability of a particular type of Electric Arc Furnace Steel Slag (EAFSS) to be recycled in the aggregate skeleton of dense graded and porous asphalt mixtures for pavements application. One dense graded mixture for wearin gcourse(WCAC), one Stone Mastic Asphalt(SMA) and one Porous Asphalt(PA) were prepared and compacted for this purpose. The computed results of Marshall Stability, Flow and Indirect Tensile Strength (ITS) values are presented in Table 1.

In this study, the synthesis of nickel nanoparticles and copper nanospheres for the potential applications of MLCC electrode materials has been studied by plasma arc evaporation method. The change in the broad distribution of the size of nickel and copper nanopowders is successfully controlled by manifesting proper mixture of gas ambiance for plasma generation in the size range of 20 to 200 nm in diameter. The factors affecting the mean diameter of the nanopowder was studied by changing the composition of reactive gases, indicating that nitrogen enhances the formation of larger particles compared to hydrogen gas. The morphologies and particle sizes of the metal nanoparticles were observed by SEM, and ultrathin oxide layers on the powder surface generated during passivation step have been confirmed using TEM. The metallic FCC structure of the nanoparticles was confirmed using powder X-ray diffraction method.

이 연구는 조합하중을 받는 변단면 변화곡선 보의 기하 비선형 수치해석 방법에 관한 연구이다. 보의 좌단은 회전지점이 고 우단은 마찰이 없는 활동(滑動)지점으로 지지되어 있어 하중이 작용하면 보의 축방향 길이가 증가하여 평형상태를 이룬 다. 조합하중은 회전지점에 작용하는 모멘트 하중과 집중하중을 고려하였다. 보의 단면은 휨 강성이 부재축을 따라 함수적 으로 변화하는 변단면으로 선택하였다. 이러한 보의 비선형 거동을 지배하는 연립 미분방정식을 Bernoulli-Euler 보 이론으 로 유도하였다. 이 미분방정식을 반복법으로 수치해석하여 보의 정확탄성곡선을 산정하였다. 이 연구의 이론을 검증하기 위하여 실험실 규모의 실험을 실행하였다.