This study evaluated the mechanical joining characteristics of substrate Al7075 using the filler metals of ER5356 and Al7075 to secure the joining integrity of the specimens by GTAW. The results of radiographic test show that the welded specimens meet the first level standard of KS D 2042. Besides, welding defects were not occurred. The tensile strengths of the specimens using the filler metals of Al7075 and ER5356 had 240MPa and 252MPa, respectively. The yield strengths were 132MPa and 120MPa, respectively. In case of using the filler metal of Al7075, However, in case of using the filler metal of ER5356, Two filler metals of Al7075 and ER5356 were similar to each other in tensile and yield strength.

PURPOSES: The new waste management policy of South Korea encourages the recycling of waste materials. One material being recycled currently is tire-derived fuel (TDF) ash. TDF is composed of shredded scrap tires and is used as fuel in power plants and industrials plants, resulting in TDF ash, which has a chemical composition similar to that of the fly ash produced from coal. The purpose of this study was to evaluate the properties of an asphalt concrete mix that used TDF ash as the mineral filler. METHODS: The properties of the asphalt concrete were evaluated for different mineral filler types and contents using various measurement techniques. The fundamental physical properties of the asphalt concrete specimens such as their gradation and antistripping characteristics were measured in accordance with the KS F 3501 standard. The Marshall stability test was performed to measure the maximum load that could be supported by the specimens. The wheel tracking test was used to evaluate the rutting resistance. To investigate the moisture susceptibility of the specimens, dynamic immersion and tensile strength ratio (TSR) measurements were performed. RESULTS : The test results showed that the asphalt concrete containing TDF ash satisfied all the criteria listed in the Guide for Production and Construction of Asphalt Mixtures (Ministry of Land, Infrastructure and Transport, South Korea). In addition, TDF ash exhibited better performance than that of portland cement. The Marshall stability of the asphalt concrete with TDF ash was higher than 7500 N. Further, its dynamic stability was also higher than that listed in the guide. The results of the dynamic water immersion and the TSR showed that TDF ash shows better moisture resistance than does portland cement. CONCLUSIONS : TDF ash can be effectively recycled by being used as a mineral filler in asphalt, as it exhibits desirable physical properties. The optimal TDF ash content in asphalt concrete based on this study was determined to be 5%. In future works, the research team will compare the characteristics of asphalt concrete as function of the mineral filler types.

For the development of a low-melting point filler metal for brazing aluminum alloy, we analyzed change of melting point and wettability with addition of Sn into Al-20Cu-10Si filler metal. DSC results showed that the addition of 5 wt% Sn into the Al-20Cu-10Si filler metal caused its liquidus temperature to decrease by about 30 oC. In the wettability test, spread area of melted Al-Cu-Si-Sn alloy is increased through the addition of Sn from 1 to 5 wt%. For the measuring of the mechanical properties of the joint region, Al 3003 plate is brazed by Al-20Cu-10Si-5Sn filler metal and the mechanical property is measured by tensile test. The results showed that the tensile strength of the joint region is higher than the tensile strength of Al 3003. Thus, failure occurred in the Al 3003 plate.

The filler was one of the structural parts using composite material. The filler manufacturing machine was effectively developed based on the principles of usability by HCI. This machine consisted of an ultrasonic cutter, heater, forming rollers and drawing motor. It applied to separate the disk-shape cutter of ultrasonic cutter in order to remove burning the knife edge of ultrasonic cutter. And the developed machine had the two-stage forming rollers for improved formability which maintained accurately the filler shape.

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.

The automotive industry is moving from the internal combustion engine to electric drive motors. Electricmotors uses a high voltage system requiring the development of resources and components to shield the system. There-fore, in this study, we analyze electromagnetic interference (EMI) shielding effectiveness (SE) characteristics of an autocrash pad according to the ratio of electrically conductive materials and propylene. In order to combine good mechan-ical characteristics and electromagnetic shielding of the automotive crash pad, metal-coated glass fiber (MGF) manufac-turing methods are introduced and compared with powder-type methods. Through this study, among MGF methods, wesuggest that the chopping method is the most effective shielding method.

A 2D axisymmetric numerical analysis was performed to study the characteristics of charge process inside solar thermal storage tank. The porosity and heat transfer coefficient of filler material as well as inlet velocity of heat transfer fluid are selected as simulation parameters. The porosity is varied as 0.2, 0.5, and 0.8 to account for the effect of filler granule geometry. Two levels of the heat transfer coefficient is adopted to assess the heat transfer between heat transfer fluid and filler material. The inlet velocity is varied as 0.00278, 0.0278, and 0.278m/s. As both of the porosity and the heat transfer coefficient increase, the discrepancy of the temperature distributions between the filler and heat transfer fluid decreases. As the inlet velocity increases, the penetration depth of the heat transfer fluid increases proportionally.

A 2D axisymmetric numerical analysis was performed to study the characteristics of charge process inside solar thermal storage tank. The interfacial area density and inertial resistance of filler material are selected as simulation parameters. The interfacial area density is varied as 800, 2000, and 4000 1/m. The inertial resistance is varied as 1, 3, and 5 1/m. When the interfacial area density increases from 800 to 4000 1/m, the discrepancy of the temperature distributions between the filler and heat transfer fluid decreases. As inertial resistance increases from 1 to 5, both of the temperature and fluid flow pattern changes considerably.

The conductive polymer composites recently became increasingly to many fields of industry due to their electrical properties. To understand these properties of composites, electrical properties were measured and were studied relatively. Electrical conductivity measurements showed percolation phenomena. Percolation theories are frequently applied to describe the insulator-to-conductor transitions in composites made of a conductive filler and an insulating matrix. It has been showed both experimentally and theoretically that the percolation threshold strongly depends on the aspect ratio of filler particles. The critical concentration of percolation formed is defined as the percolation threshold. This paper was to study epoxy resin filled with copper. The experiment was made with vehicle such as epoxy resin replenished with copper powder and the study about their practical use was performed in order to apply to electric and electronic industry as well as general field. The volume specific resistance of epoxy resin composites was 3.065~13.325 in using copper powder. The weight loss of conductive composites happened from 350℃~470℃.

Effects of the amount of nickel powder (Ni) in Ni-carbon fiber (CF) hybrid filler systems on the conductivity(or resistivity) and thermal coefficient of resistance (TCR) of filled high density polyethylene were studied. Increases of the resistivity and TCR with increasing Ni concentration at a given hybrid filler content were observed. Using the fiber contact model, we showed that the main role of Ni in the hybrid filler system is to decrease the interfiber contact resistance when Ni concentration is less than the threshold point. The formation of structural defects leading to reduced reinforcing effect resulted in both a reduction of strength and an increase of the coefficient of thermal expansion in the composite film; these changes are responsible for the increases of both resistivity and TCR with increasing Ni concentration in the hybrid filler system.

본 연구는 도축장에서 폐기되는 도축 반추위 내용물을 사일리지 혹은 TMR (total mixed ration) 사료 첨가용 효소제로 개발하기 위한 목적으로 수행되었다. 도축 반추위 내용물에는 상당한 수분이 함유되어 있어, 적절한 건조과정을 거치지 않고서는 그 활용이 원활하지 않다. 그러나 효소는 열에 민감한 단백질로 구성되어 있기 때문에 적절한건조 조건의 개발이 필요하다. 본 연구에서는 통계적 방법을 이용하여 가열온도 (60, 75, 90°C), 가열시간 (12, 30, 48시간) 및 부형제의 비율 (12, 22.5, 33%)이 도축 반추위 내용물에 함유된 다양한 효소활성에 미치는 효과를 분석하였다. 총 3가지 효소, xylan 분해효소, 셀룰로오스 분해효소및 전분 분해효소를 검토하였고, 각 효소활성들에 대한 각요인들의 효과가 매우 다양하게 나타났다 (p<0.05). 셀룰로오스 분해효소와 전분 분해효소의 활성은 가열온도가 증가함에 따라 감소하였으며 (p<0.05), xylan 분해해소는 열에대한 안전성이 다른 효소들에 비하여 우수하였다. 자일란,셀룰로오스, 전분 분해효소를 증가시키는 적정 부형제의비율은 22.5, 12 그리고 33%로 나타났다. 비록 3가지 효소들의 제형화에 있어 공통적으로 적용될 수 있는 최적점을도출하지는 못하였으나, 본 연구결과에서 얻어진 효소들의반응 값들을 이용하여 목적하는 효소에 따라서 다양한 방법으로 적용이 가능할 것으로 판단된다.

Recently, inorganic-organic hybrid materials have attracted much attention not only for their excellent thermal conductivity but also for their flame retardant properties. In this study, the properties of organic-inorganic hybrid insulating materials using inorganic fillers and polyurethane foam with different foaming conditions have been investigated. The addition of 1.5 wt% water to polyurethane as foaming agent shows the best foaming properties. The pore size was decreased in the foaming body with increasing of the CaCO3 addition. The apparent density and thermal conductivity were increased by increasing the CaCO3 addition. With an increasing amount of CaCO3 powder, the flame retardant property is improved, but the properties of thermal conductivity and apparent density tend to decrease. When the addition of fine particles of CaCO3, the apparent density and thermal conductivity were increased and, also, with the addition of coarse particles over 45μm in size, the apparent density and thermal conductivity were increased as well. In this study, the adding of CaCO3 with average particle size of 27μm led to the lowest thermal conductivity and apparent density. After evaluation with different inorganic fillers, Mg(OH)2 showed the highest thermal conductivity; on the other hand, CaCO3 showed the lowest thermal conductivity.

PTMSP에 20 wt% PMMH dendrimer와 10, 20, 30, 40 wt% NaY zeolite를 가하여 PTMSP-PMMH-NaY zeolite 복합막을 제조하였다. 복합막의 물리화학적 특성을 FT-IR, TGA, SEM을 사용하여 조사하였고, H2와 N2 기체에 대한 투과도와 선택도 성질을 고찰하였다. PTMSP-PMMH-NaY zeolite 복합막의 투과도는 zeolite 함량이 증가함에 따라 증가하였고, 수소와 질소의 투과도는 각각 3,950~592,000 barrer와 1,550~143,000 barrer를 보였다. 질소에 대한 수소의 선택도는 0~30 wt%에서는 뚜렷한 차이가 나타나지 않았고, 30~40 wt%에서는 2.2~4.2 범위로 증가하는 경향을 보였다.

A chemical process involves polymerization within microspheres, whereas a physical process involves the dispersion of polymer in a nonsolvent. Nano-sized monodisperse microspheres are usually prepared by chemical processes such as water-based emulsions, seed suspension polymerization, nonaqueous dispersion polymerization, and precipitation polymerizations. Polymerization was performed in a four-necked, separate-type flask equipped with a stirrer, a condenser, a nitrogen inlet, and a rubber stopper for adding the initiator with a syringe. Nitrogen was bubbled through the mixture of reagents for 1 hr. before elevating the temperature. Functional silane (3-mercaptopropyl)trimethoxysilane (MPTMS) was used for the modification of silica nanoparticles and the self-assembled monolayers obtained were characterized by X-ray photoelectron spectroscopy (XPS), laser scattering system (LSS), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), elemental analysis (EA), and thermogravimetric analysis (TGA). In addition, polymer microspheres were polymerized by radical polymerization of γ-mercaptopropyl modified silica nanoparticles (MPSN) and acrylamide monomer via precipitation polymerization; then, their characteristics were investigated. From the elemental analysis results, it can be concluded that the conversion rate of acrylamide monomer was 93% and that polyacrylamide grafted to MPSN nanospheres via the radical precipitation polymerization with AAm in ethanol solvent. The microspheres were successfully polymerized by the 'graft from' method.

Joining of NiO-YSZ to 316 stainless steel was carried out with B-Ni2 brazing alloy (3 wt% Fe, 4.5 wt% Si, 3.2 wt% B, 7 wt% Cr, Ni-balance, m.p. 971-) to seal the NiO-YSZ anode/316 stainless steel interconnect structure in a SOFC. In the present research, interfacial (chemical) reactions during brazing at the NiO-YSZ/316 stainless steel interconnect were enhanced by the two processing methods, a) addition of an electroless nickel plate to NiO-YSZ as a coating or b) deposition of titanium layer onto NiO-YSZ by magnetron plasma sputtering method, with process variables and procedures optimized during the pre-processing. Brazing was performed in a cold-wall vacuum furnace at . Post-brazing interfacial morphologies between NiO-YSZ and 316 stainless steel were examined by SEM and EDS methods. The results indicate that B-Ni2 brazing filler alloy was fused fully during brazing and continuous interfacial layer formation depended on the method of pre-coating NiO-YSZ. The inter-diffusion of elements was promoted by titanium-deposition: the diffusion reaction thickness of the interfacial area was reduced to less than 5 compared to 100 for electroless nickel-deposited NiO-YSZ cermet.

To investigate new potential application of a clay material for C/C composites, illite added C/C composites were prepared with various illite contents. The improvement of filler effect by illite size reduction was also investigated using wet ballmilling by evaluating illite/phenolic resin infiltration using bulk density and porosity measurements, chemical structural changes of the composites using XRD, and thermal oxidation stability in air of the composites using TGA. The size reduction of illite resulted in narrower particle size distribution and improved illite infiltration into carbon preform. And the resultant C/C composites prepared with illite had even more improved thermal oxidation stability in air, showing more increased IDTs up to 100℃, compared to those of the C/C composites with pristine illite, due to the SiC formation through carbothermal reduction between illite and carbon materials. The illite induced delay in oxidation of the illite-C/C composites was also observed and the delayed oxidation behavior was attributed to the layered structure of illite, which improved illite/phenol resin infiltration. Therefore, the potential use of illite as filler to improve oxidation stability of C/C composite can be promising. And the size reduction of illite can improve its effect on the desired properties of illite-C/C composites even more.

Composites of ceramic powders and an elastomer-based matrix were prepared by mixing CaCO3 powders with polyethylene and polypropylene elastomers, and their mechanical and sound insulation properties were measured. CaCO3 powders with 0.7 μm and 35 μm particle size were added to elastomers up to 80 wt%. Scanning electron microscopy photographs showed uniform distribution of the CaCO3 powders in the matrix. While density and surface hardness increased, melt index, tensile strength and elongation of the composites decreased as the amount of added CaCO3 powders increased. As more CaCO3 powders were added sound transmission loss of the composites increased owing to the increase of density. Addition of 0.7 μm sized CaCO3 powders resulted in a slightly higher transmission loss than the addition of 35 μm sized powders because of the increased interface area between the elastomer matrix and the CaCO3 powders. Composites with a polyethylene matrix showed higher transmission loss than those with a polypropylene matrix because the tensile strength and hardness of the polyethylene-based composites were low and their elongation was high.

Reflection properties, such as specular reflection and diffuse reflection, are very important optical properties for the reflector, which has high reflectance in the display and architecture industry. Calcite is lowcost, nontoxic, and stable over a wide temperature range. Therefore, it is one of the most widely using fillers in many industries and has some advantages over titania as a filler to improve reflectance. However, optical properties, especially those of ceramic-filled composites, have not been analyzed. We studied the reflectance of calcite composites with their surface roughness. The reflectance of the composites was determined using a UV-visible spectrometer. The surface morphology and the micro-structure of the composites were investigated by atomic force microscope. The reflectance of the composites was improved by increasing the content of calcite in the calcite-frit composite. The reflectance is related with the surface roughness in the composites. However, the reflectance depends on the calcite contents in materials with similar surface roughness.

본 연구에서는 poly(acrylonitrile-butadiene-styrene) (ABS)에 carbon graphite와 zeolite 4A를 첨가하여 복합 필름을 제조하고 공기와 수증기 투과 특성을 살펴보았다. 복합 필름의 경우 모든 경우에서 순수한 ABS에 비해서 산소와 질소의 투과도가 감소하였으며, 산소의 투과도 감소가 질소의 투과도 감소보다 약간 큰 관계로 산소/질소 선택도도 조금 감소하였다. 또한, 수증기 투과도도 순수한 ABS에 비해서 약 1/2로 감소하였다. 이러한 투과도의 감소는 ABS에 filler를 첨가함으로 인하여 물질 확산 경로의 tortuosity가 증가했기 때문인 것으로 생각된다.