In this study, factors analysis is performed for reducing friction in elevation motion of a large television stand over 50 inch. The first study is for specification decision and volume compensation experiment as an apparatus for compensating of the volume of the cylinder is compressed as the volume of piston rod. The second study is for optimized piston structure development by comparison pipe orifice and labyrinth orifice. Consequently, the result of total consideration in stability problem and performance of volume compensation for specification decision and volume compensation experiment is determined the final speculation of hollow rod ∅8 x ∅4 and riveting system. and the labyrinth orifice is not founded that of the Ø0.4~0.6 orifice both tests on 300 mm intervals.

In this study, The first study attempted to reduce the frictional force the gas seal lip technology. The second study is for specification decision and volume compensation experiment as an apparatus for compensating of the volume of the cylinder is compressed as the volume of piston rod. Consequently, in the gas seal lip technology, the outer-in diameter of ∅20 x ∅8 in the test result of hollow rod is revealed more proper if the weight of 50 inch television assumed as 30 kg. and the result of total consideration in stability problem and performance of volume compensation for specification decision and volume compensation experiment is determined the final speculation of hollow rod ∅8 x ∅4 and riveting system. The spring constant(K) showed an excellent value above the target value of 0.01 to 0.015 N/mm.

In this study, factors analysis is performed for reducing friction in elevation motion of a large television stand over 50-inch. The first is a pipe type cross-section control for accurate position control of the piston rod. Here it was compared with the pipe type and labyrinth type orifice cross-section. The second study is for specification decision and volume compensation experiment as an apparatus for compensating of the volume of the cylinder is compressed as the volume of piston rod. Consequently, in the orifice cross section study between pipe type and labyrinth type through CAE and experimental consideration, cross section of labyrinth type orifice is preferred for reducing of friction. The result of total consideration in stability problem and performance of volume compensation for specification decision and volume compensation experiment is determined the final speculation of hollow rod φ8×φ4 and riveting system.

To precisely assemble the fuel test rod, an orbital TIG welding system was designed and developed to accurately conduct orbital TIG welding for the nuclear fuel test rod. Using this system, a welding process needs to confirm the welding properties for orbital TIG welding. Therefore, preliminary weld tests were performed on the cladding tubes under various conditions, and the results show that the width and depth of HAZ of the cladding specimen welded using identical power during an orbital TIG welding cycle was continuously increased from a welded start-point to a welded end-point because of heat accumulation. The performance tests were conducted under the welding conditions considered through preliminary welding tests, and the properties of the specimens were conformed through surface and microstructure analyses.

By controlling the piston speed of the gas spring applying to the digital television stand application of the gas spring, a user can operate the elevation when the gas spring is working under long stroke(200～300 mm, the TV elevation displacement). According to stroke, by some devices with the problem rising from between the difference of external forces, the emotional quality in television elevational function is realized. The piston speed control technique is investigated to perform this experiment piston flow analysis and flow rate control for precise tubular cross section and propose a piston structure for elevation action. This study is for the development of the gas spring of the large size television stand with 50 inch over. In the gas spring development of elevation working, a device to compensate for the volume of the cylinder is generated as much the volume of the piston rod. As this study result, at the development of working gas spring, the hollow shaft is more favorable than the solid one in the apparatus to compensate for the cylinder volume generated.

When an engine connecting rod is designed, it’s important to consider the buckling strength as well as deformation and durability of the rod. The buckling strength of a rod is mainly affected by the shape and area of shank cross-section and boundary conditions of its small and big ends. Buckling analysis by finite element method was carried out to evaluate the elastic buckling strength of a connecting rod that has non-uniform cross section areas. And the Merchant-Rankine formula was applied to predict the inelastic critical buckling load by considering the plastic buckling strength. Finally, the maximum allowable compressive load, which has 56.57kN, was predicted by considering the 1.7 buckling safety factor. It represents an approximately 40% greater than the maximum firing pressure.

The present experimental study investigates single-phase heat transfer coefficients downstream of support grid in 6×6 rod bundles. Support grid with Split mixing vanes enhance heat transfer in rod bundles by generating turbulence but this turbulence is confined to a short distance. Support grid with large scale vortex flow(LSVF) mixing vanes enhanced heat transfer to a longer distance. In this study, the experiments were performed at reynolds numbers of 50,000. The characteristics of the heat transfer enhancement of the Split mixing vane and those of the LSVF mixing vane were compared. The results showed that the characteristics of the heat transfer enhancement of rods by the Split mixing vane were limited to 10 Dh after the spacer grid, but those by the LSVF mixing vane were maintained until 15 Dh after the spacer grid. For the reynolds number of 50,000, the heat transfer enhancement effect was 3.0% greater when using the LSVF mixing vane than when using the Split mixing vane between the 1 ∼ 15 Dh interval after the spacer grid.

This paper shows the simplified equation to predict the ultimate moment capacity and corresponding rod stress in reinforced concrete beam with external post-tensioning rods. Because the stress of external post-tensioning rod depends on the beam deflection, the previous analytical model for post-tensioned beams requires a tedious iteration process. Also, the stress equations in ACI code or other researchers’ models are suitable only for internal tendons in concrete beams. In this study, given the lack of analytical approaches to predict the nominal stress of the external unbonded rod, a simple and robust equation has been proposed for externally post-tensioned concrete beams. It is concluded that the proposed equation predicted the stress of external steel rods in post-tensioned concrete beams reasonably well.

To conduct a nuclear fuel irradiation test, the inside of the nuclear fuel rod must be assembled along with the test fuel, several different parts, and sensors, and then filled with high-pressure and high-purityhelium gas. Therefore, it is necessary to develop helium gas filling techniques that can achieve exact TIG (Tungsten Inert Gas) spot welding at a pin-hole of the nuclear fuel rod to fill helium gas into the nuclear fuel test rod. However, previous apparatuses do not have repeatability for TIG spot welding as they lack an electrode position control jig to exactly fix a TIG electrode in a high-pressure chamber, and they consume a large amount of helium gas. Therefore, a TIG spot welding apparatus was developed to easily and accurately conduct TIG spot welding and significantly reduce the gas consumption. In addition, the optimum welding conditions of this welding apparatus were established through various weld tests.

In this study, shaking table test was carried out to evaluate the seismic behavior and performance of low-rise reinforced concrete (RC) piloti structures with and without retrofit. The specimens were designed considering the characteristics of existing building with pilotis such as natural period, distribution factor of strength and stiffness between columns and core wall on the first soft story. The test for the non-retrofit specimen showed that damage was concentrated on the stiffer member on the same floor as the core wall failed by shear fracture whereas columns experienced slight flexural cracks. Considering the failure mode of the non-retrofit specimen, the retrofit method using steel rod damper was presented for improving the seismic performance of piloti structures. The results of the test for retrofit specimen revealed that the retrofit method was effective for controlling the damage as the main RC structural members were not destroyed and most of input energy was dissipated by hysteretic behavior of the damper.

목적: 원거리 마독스로드 검사에서 눈부심이 프리즘 교정에 미치는 영향을 알아보고자 하였다. 방법: 양안시 기능(조절, 버전스)이 정상인 성인 60명(외사위 35명, 내사위 25명)을 대상으로 마독스로드 검사를 사용하여 광원을 통해 눈부심이 유발된 경우와 유발되지 않은 경우의 원거리 수평사위의 교정 프리즘 굴절력을 측정하였다. 마독스로드 검사는 눈부심을 유발하기 위해 서로 다른 광원의 밝기를 사용하여 밝은 조명 및 어두운 조명에서 실시하였다. 또한 마독스로드 검사 및 수정토링톤 검사를 사용하여 밝은 조명에서 눈부심이 유발되지 않은 광원을 사용한 경우 원거리 수평사위의 교정 프리즘 굴절력을 측정하였다. 결과: 외사위 및 내사위의 경우 마독스로드 검사는 밝은 조명(800lux)에서 눈부심이 유발되지 않은 광원(850cd/m2), 어두운 조명(20lux)에서 눈부심이 유발된 광원(850cd/m2), 이전의 동일한 어두운 조명(20lux)에서 눈부심이 유발되지 않은 광원(20cd/m2)을 사용하여 측정된 교정 프리즘 굴절력은 서로 통계적으로 유의한 차이가 있었고[(F=12.16, p=0.00),(F=8.03, p=0.00)], 모두 내사위 경향을 보여 주었다. 외사위 및 내사위의 경우 밝은 조명(800lux)에서 눈부심이 유발 되지 않은 광원(850cd/m2)을 사용한 경우 마독스로드 검사와 수정토링톤 검사에서의 원거리 수평사위의 교정 프리즘 굴절력은 각각 -2.07±0.43△, -2.11±0.67△ 및 1.24±0.31△, 1.10±0.36△이었고 통계적으로 서로 유의한 차이는 없었다[(t=0.19, p=0.85), (t=1.32, p=0.20)]. 결 론: 마독스로드 검사를 광원 밝기에 비해 상대적으로 어두운 공간에서 실시하는 경우 눈부심이 유발될 수 있다. 그 결과 눈부심은 마독스로드 검사를 통한 원거리 수평 사위 검사에서 피검자에게 일정한 근거리 조절 효과를 유발하고 결과적으로 내사위 경향이 나타나는 것으로 사료된다. 또한 일상 조명과 유사한 밝은 공간에서 눈부심 유발이 없는 광원을 통해 마독스로드 검사를 실시하는 경우 조절변화에 대한 통제가 상대적으로 쉬울 것으로 사료된다.

In this paper, heat treatment on the cutting device for automatic welding electrode is proposed. The electrode can be fed continuously by general automatic welding. When the leading end of wire is bent, it must be cut with the constant length. The wire has been cut by manual method previously but the automatic cutter device is proposed and designed in this study. These new device parts are designed and the heat treatment of cutter is determined analytically. The numerical three-dimensional analysis is carried out by means of DEFORMTM-HT, the common heat-treatment software. The meshes are divided with tetrahedral elements. As the result, the highest hardness is observed at the end edge of cutter and especially the hardness at edge is reached even HRc 64.3. The layer, 90% of which consists of martensite structure, is extended to the end edge of cutter. And the layer, 50% of which consists of the micro-structure, becomes its middle area. Because the mechanical property can be predicted by this analytical approach, it is not necessary to have any onsite heat treatment. The life of cutter can be improved by using this study result.

This study analyzes lifes and damages at automotive tie rod through the structural analyses with fatigue. The structural result of this study can be effectively utilized with the design of automotive tie rod by investigating prevention and durability against its damage.

When a new nuclear fuel is developed, irradiation test needs to be carried out in the research reactor to analyze the performance of the new nuclear fuel. It is necessary to attach sensors in the fuel rod and connect them with instrumentation cables to check the performance of the nuclear fuel during the burn up test in the test loop. A thermocouple is installed at the center of the fuel rod to check the centerline temperature of a fuel rod during the irradiation test. Therefore, A hole needs to be made at the center of a fuel pellet to put the thermocouple. However, it is difficult to make a small fine hole on the sintered UO2 pellet with a simple drilling machine, because the hardness and density of a sintered UO2 pellet are very high. In this study, an instrumented fuel rod mock-up was fabricated using an automated precise drilling machine. Four sintered alumina were drilled off and assembled into the zircaloy tube and a thermocouple was instrumented in the fuel rod mock-up. Sealing of an instrumented fuel rod mock-up was performed in the following two methods. It is sealing of similar metals perform by welding method, and sealing of dissimilar metals perform by swagelok method.

목 적: 마독스로드법(MR)과 수정된 토링톤법(MT)에서 사용하는 주시시표에 대한 조절반응량을 측정하여 수평사위량이 다르게 측정되는 요인을 알아보고자 하였다. 방 법: 양안시기능이 정상인 성인 34명(24.44±3.47세)을 대상으로 원거리와 근거리에서 마독스로드법과 수정된 토링톤법으로 수평사위를 측정하고, 근거리(40cm)에서 문자시표와 점광원, 선조광을 주시할 때 조절반응량을 자동굴절력계(NVision-K 5001, Shin-Nippon, Japan)로 측정하였다. 결 과: 마독스로드법과 수정된 토링톤법으로 측정한 원거리와 근거리의 수평사위량은 외편위가 감소하는 (내편위의 증가) 경향으로 나타났다(DLP: p = 0.022, NLP: p = 0.045). 검사거리 40 cm에서 문자시표 (20/20, 20/30)와 점광원(녹색, 백색, 적색)을 주시할 때 조절반응량은 유의한 차이가 없었다(F = 0.990, p = 0.415). 마독스로드법과 수정된 토링톤법에서 40 cm에 위치한 녹색 점광원과 선광원에 대한 조절반응량은 선광원을 주시할 때 증가하였지만 유의한 차이가 없었다(P(MR) = 0.091, P(MT) = 0.128). 백색 점광원과 선광원에 대한 조절반응량은 유의한 차이가 있었고(P(MR) = 0.000, P(MT) = 0.037), 적색 점광원과 선광원에 대 한 조절반응량도 유의한 차이가 있었다(P(MR) = 0.002, P(MT) = 0.001). 결 론: 마독스로드법으로 측정한 수평사위량이 다른 사위검사보다 외편위의 감소(내편위의 증가)가 나타나는 것은 조절반응량이 증가로 인한 것이 아닌 선광원에 의한 근접성폭주의 과도한 작용으로 인한 것으로 사료된다.

공칭 세공크기 0.1 μm이고 내경이 5 mm인 정밀여과용 관형 분리막 내에 자체 설계한 배출봉을 삽입하여 막오염 감소효과에 따른 투과유속을 측정하였다. 원료용액으로는 에멀젼 상태의 dioctyl tinoxide (DOTO) 입자를 사용하였으며 0.5 wt%까지 농도를 변화시키면서 1.6 bar 이내에서 운전하였다. 배출봉의 효과는 매 실험마다 배출봉을 삽입한 경우와 사용하지 않은 경우의 투과유속을 비교하여 평가하였다. 배출봉을 사용할 경우 운전압력 1.6 bar에서 최대 20%의 투과유속이 향상되었다. 또한 DOTO 농도가 증가함에 따라서 배출봉에 의한 투과유속 향상효과는 크게 나타났으며 0.5 wt% 농도에서 43%까지 투과유속이 향상되었다.