콘크리트 포장의 평탄성과 내구성은 환경 조건에 크게 영향을 받으며, 슬래브 상하부 간의 온습도 차이는 부등건조수축 및 와핑 (Warping) 현상을 유발하여 포장의 장기 성능 저하를 초래할 수 있다. 이는 주행성 저하, 균열 발생, 유지보수 비용 증가의 원인이 되 며, 특히 터널과 같은 특수 환경에서는 상하부 간의 습도 차이가 더욱 크게 나타나 부등건조수축이 심화될 가능성이 높다. 터널 내부 는 직사광선의 영향을 받지 않지만, 통풍이 잘 이루어져 건조한 환경이 조성되며, 이러한 조건에서는 슬래브 상부에서 수분 손실이 가 속화되고 하부는 습윤 상태를 유지하여 상하부 간의 큰 습도 차이를 발생시킨다. 이는 슬래브의 비균일한 수분 이동을 유발하여 부등 건조수축을 더욱 크게 발생하게 한다. 국내에서는 터널 길이가 500m 이상인 장대 터널에서 콘크리트 포장 적용이 증가하고 있으며, 아스팔트 포장 대비 화재 시 유독가스 발생 위험이 낮다는 이유로 국토교통부에서 콘크리트 포장을 권장하고 있다. 이로 인해 터널 내 콘크리트 포장의 사용이 증가하고 있 으나, 기상환경 변화 및 습도 관리 미흡으로 인해 콘크리트 포장 줄눈부에서의 평탄성 불량 문제가 빈번하게 발생하고 있다. 이러한 문제는 주행성 저하, 도로 이용자의 민원 증가 및 유지보수 비용 상승을 초래하고 있어, 구체적인 원인 분석과 대책 마련이 필요한 실 정이다. 따라서 본 연구는 터널과 같은 특수 환경에서 습도 조건이 콘크리트 슬래브의 부등건조수축에 미치는 영향을 실험적으로 분석하고, 슬래브의 수평 변형률 및 수직 변위를 측정하여 건조 수축에 따른 변형 거동을 정량적으로 평가하고자 하였다. 다양한 습도 조건에서 슬래브의 변형 양상을 비교 분석함으로써, 터널 환경에 적합한 콘크리트 포장 설계 및 유지관리 기준을 제시하고, 콘크리트 포장의 장 기 성능을 개선하기 위한 대책을 마련하고자 한다.

본 논문은 모바일 폰 사진을 활용하여 도시 공간에서 전력선과 건물 사이의 거리를 편리하게 모델링하고 측정하는 방법에 중점을 두고 있으며, 이에 대한 정확성을 평가하였다. 모바일 장 치용 2뷰 지오메트리를 사용한 전력선과 건물의 3D 재구성 방법을 설계하여 어디에서나 즉시 측정할 수 있도록 하였다. 특징점을 사용하여 전력선과 건물 사이의 거리를 계산하고 건물 정 보를 활용하여 게임 가상 공간에 전력선과 전주를 배치할 수 있다. 본 논문에서는 대전시 내 10개의 위치에서 실험을 실시하고, 상업용 시스템과 LiDAR가 있는 경우와 없는 경우를 포함 한 이전 방법과의 성능을 평가하였다. 우리의 방법을 스마트폰에 구현했기 때문에 장점은 휴 대성과 저렴함이다.

현대 건설산업 분야에서 철근콘크리트는 반영구적인 재료로 인식되어 가장 많이 사용되고 있다. 하지만 콘크리트의 노후화 및 수분 용해 현상 등으로 생긴 균열을 통해 강재의 부식이 발생하게 된다. 이러한 부식은 철근콘크리트의 거동과 구조물의 내구성을 저하시키기 때문에 근본적인 원인인 강재를 대체할 필요가 있다. 최근 건설산업에서 복합재료는 높은 강도, 낮은 중량, 부식에 대한 우 려가 없어 주목받고 있는 재료이다. 복합재료는 섬유와 기지재료로 사용되는 수지에 따라 재료의 특성이 달라지게 되며 이중 탄소섬유 를 활용한 복합재료 CFRP은 복합재료 중 가장 뛰어난 성능을 보여준다. 따라서 본 연구에서는 뛰어난 성능을 보여주는 CFRP와 경제 성을 고려하여 탄소섬유와 유리섬유를 혼합한 CFRP Hybrid를 사용하여 강재의 대체품으로 사용가능성을 확인하고자 한다. 재료의 특 성을 비교하기 위하여 ASTM 규정에 따라 인장시험과 압축시험을 수행하고 반복하중에 대한 저항을 확인하기 위하여 인장반복시험과 압축반복시험을 수행한다. 이때 측정된 응력, 영구변형 등을 그래프로 도식화하고 강재와 비교분석을 진행하였다.

최근 해상 교통량 증가 및 연안 중심의 레저활동으로 인해 다양한 해양사고가 발생하고 있다. 그 중 선박사고는 인 명 및 재산 피해를 유발할 뿐만 아니라 기름 및 위험·유해물질 유출을 동반한 해양 오염사고로 이어질 가능성이 크다. 따 라서 해양사고 대비 및 대응을 위한 지속적인 선박 모니터링이 필요하다. 본 연구에서는 해상 선박 모니터링 체계 구축을 위한 초분광 원격탐사 기반의 항공 실험 수행 및 선박탐지 결과를 제시하였다. 한반도 서해 궁평항 인근 해역을 대상으로 초분광 항공관측을 수행하였으며, 사전에 다양한 선박 갑판에 대한 분광 라이브러리를 구축하였다. 탐지 방법으로는 spectral correlation similarity (SCS) 기법을 사용하였으며 초분광 영상과 선박 스펙트럼 사이의 공간 유사도 분포를 분석하 였다. 그 결과 초분광 영상에 존재하는 총 15개의 선박을 탐지하였으며 최대 유사도에 기반한 선박 갑판의 색상도 분류하 였다. 탐지 선박들은 고해상도 digital mapping camera (DMC) 영상과의 매칭을 통해 검증하였다. 본 연구는 해상 선박탐지 를 위한 항공 초분광 센서 활용의 기초로서 향후 원격탐사 기반의 선박 모니터링 시스템에 주요 역할을 할 것으로 기대된 다.

In this paper, as there are many cases of fires occurring due to the failure or inoperability of the thermostat of electronic products, the purpose is to test and analyze the risks and probabilities through fire cases and reproduction experiments, and suggest countermeasures. Among electronic products, water purifiers are composed of a refrigerant system with a compressor to make cold water, a heating device to make hot water, and an electric device used as an energy source. Due to the nature of the water purifier manufacturing, these devices are subject to a lot of moisture and dust. etc. exist in large quantities and use electrical energy, so there is a possibility of fire due to short circuit in the wire, electrical abnormal overheating (tracking phenomenon) in the thermostat, electronic board, starting relay, etc., and overheating of the heating device (Band Heater). there is. Therefore, in order to prevent fires from these devices, a system to remove foreign substances inside the water purifier is necessary, the use of heat-resistant (fire-resistant) wires for electrical devices is essential, and the use of non-combustible materials (semi-combustible materials) for each part is necessary to prevent fire. The risk must be eliminated through prevention and combustion expansion prevention devices.

As a safety device, a rupture disc are used to control pressure to minimize the explosion risk once the internal pressure of high pressure equipment exceeds a critical level. In this paper, optimization method was developed to secure optimal design of domed Rupture disks. The parameter analysis was performed through design of experiment to parameter of Rupture disk made of AISI 316.The Diameter, Thickness and Hight of Rupture disk were selected as design parameters for design parameter analysis. The results of parameter analysis revealed that the Diameter, thickness and hight were burst pressure-sensitive design parameters. Based on the valid performance factors, a regression equation to predict its performance was deducted and using the equation, an optimal design. And a sample model was fabricated, followed by burst pressure testing, after optimal design and analytical verification. In this research, it is verified that the optimal design method and the credibility of the analysis of this study is deemed very high. Furthermore, utilizing this mechanism would inspect the effect of the design parameter performance and increase the credibility and efficiency of a design.

In order to attract students to the radio universe, we have constructed a three-element radio interferometer in the National Youth Space Center, Goheung, Korea. It consists of three 1.8 m off-axis parabola antennas with driving systems, sideband separation receivers operating in 12 GHz, a narrow band digitizer, and correlation software. We have used as many commercial products as possible to reduce development costs. The maximum separation of 20 m gives an angular resolution of ∼4′, and the shortest baseline of 3.8 m prevents a serious missing flux. Fringes are detected for several radio sources, including the sun and Cas A. After a rough relative calibration, we have derived visibilities for the sun, whose amplitudes are decreasing for longer baselines. We have made a solar image using the visibility amplitudes and closure phases, referring to the 17 GHz image by Nobeyama Radioheliograph. Developing a flexible real-time correlator seems most crucial if this kind of the system is to be used for more rigorous scientific studies.

This paper describes the development and operation of an autonomous robotic system designed for pyroprocess automation. The unique challenges of pyroprocess automation, such as the need for a highly dry atmosphere to handle materials like chloride, are addressed through this system. For the experiments, a specialized dehumidifier and dry mock-up facility were designed to produce dry air condition. Performances of dry air conditioning for the various simulated situations were evaluated, including assessing worker access within a mock-up to determine the system’s feasibility. To enable automation, containers used for processing materials were modified to fit the gripper system of the gantry robot. The loading and unloading of materials in each equipment were automated to connect them with the robotic system. This gantry robot primarily utilized macro motions to approach waypoints containing process materials, reducing the need for precise approach motions. Its tapered jaw design allowed it to grip target objects even with imperfect positioning. The robot’s motions were programmed initially using a robot simulator for positioning and motion planning, and real-world accuracy was tested in a dry mock-up facility using the OPC platform. Finally, the paper discusses the potential application of XR (eXtended Reality) technology in this context, which could enhance the robot’s operation and provide valuable insights into the automation process. Further analysis of XR technology’s feasibility and benefits for this specific pyroprocess automation system are presented.

The automotive industry continuously strives to enhance safety for both drivers and passengers through technological advancements. Car side impacts have the potential to significant risks to passengers, So the automotive industry has proposed various technological solutions. As part of these efforts, the development of side impact beams, which are affixed to the inner frame of vehicle side doors to absorb and dissipate collision energy, has been a safety enhancement. Conventional side impact beams are manufactured using hot-rolled steel sheets and have a pipe-like configuration. However, these impact beams are fixed to the vehicle's chassis, which directly transfers the energy generated during a collision to the chassis frame. This paper aims to address this issue by proposing the development and optimization of vehicle door impact beams using a dual-beam structure and fastening method, utilizing shear bolts. Moreover, the focus is on optimizing the cross-sectional shape of the dual-beam impact structure. The evaluation criterion for optimization is based on the second moment of area of the cross-section. To validate these improvements, Static experiments were conducted, comparing the proposed dual-beam structure with the traditional impact beam. This research is expected to serve as a guideline for enhancing vehicle safety through design directions and validation methods.

In this study, the thermal equilibrium of a motor operated in the sea and the temperature in the equilibrium were studied. To predict the equilibrium temperature in the sea, the cooling performance of the motor was studied by comparing results of analysis and experimental results in the air condition. By this study, the method of prediction of the cooling performance of a motor in various environments could be useful.

최근 들어 반려동물을 키우는 가구 수가 증가하고 있다. 그로인해 진드기와 냄새에 대한 관심 또한 증가하고 있다. 본 연구는 제충국 추출물 (Tanacetum cinerariifolium), 수용성 피톤치드(water-soluble phytoncide)가 진드기 퇴치제로서 효과와 탈취 및 항균 효과가 있는지 알아보기 위하 여 연구를 진행하였다. 틱 클라이밍 테스트(Tick climbing test)에서 제충국 추출물(Tanacetum cinerariifolium) 23.33점, 수용성 피톤치드 22.00점 으로 높은 기피효과를 보였다. 복합추출물로서의 진드기 기피 효과를 확인하기 위해 위 실험에서 기피 효과가 확인된 제충국 추출물, 수용성 피톤치 드를 포함한 복합추출물(Sample이라 함.), 타사 제품(Control이라 함.)로 틱 클라이밍 테스트(Tick climbing test)를 진행하였다. 결과 Sample 13.00점, Control 26.67점으로 Sample이 높은 기피 효과를 나타내었다. 참진드기 실내 기피제 효력 시험법에서도 Sample이 88%, Control이 12%로 우수한 진드기 기피효과를 보인다는 것을 확인하였다. Sample을 가지고 탈취 시험을 진행한 결과 암모니아에서 98.3%, 트리메틸아민에서 99.5%의 탈취 효과를 보여주었으며, 항균시험에서 대장균, 황색포도상구균, 폐렴균 모두 99.9%의 항균 효과를 보여주었다. 본 연구결과를 종합해 볼 때 위 소재를 포함한 복합추출물은 추후 진드기 기피제와 탈취 및 항균에도 효과가 있는 소재로서의 활용 가치가 높다고 판단된다.

Solubility and species distributions of radionuclides in domestic groundwater conditions are required for the safety assessment of deep underground disposal system of spent nuclear fuel (SNF). Minor actinides including Am contribute significant extents to the long-term radiotoxicity of SNF. In this study, the solubility of Am was evaluated in synthetic groundwater (Syn-DB3), which were simulated for the groundwater of the DB3 site in the KAERI Underground Research Tunnel (KURT). Geochemical modeling was performed based on the ThermoChimie_11a (2022) thermochemical database from Andra to estimate the solubility and species distributions of Am in the Syn-DB3 condition. Dissolved Am concentrations in the Syn-DB3 were experimentally measured under oversaturation conditions. Am(III) stock solution in perchlorate media was sequentially diluted in Syn-DB3 to prepare 8 μM Am(III) in Syn-DB3. The pH of the solutions was adjusted to be in the range of 6.4–10.5. A portion of the samples was transferred to quartz cells for UV-Vis absorption and time-resolved laser fluorescence spectroscopy studies and the rest were stored in centrifuge tubes. The absorption spectra of the samples were monitored over 70 days and the results suggest that Am colloidal particles were formed initially in all the samples and precipitated rapidly within two days. Over the experimental period of 236 days, small volume (10 μL) of the samples in the centrifuge tubes were periodically withdrawn after centrifugation (18000 rpm, 1 hr) for the liquid scintillation counting to measure the concentrations of Am dissolved in Syn-DB3. In the end of the experiments, pH of the samples was checked again and the final dissolved Am concentrations were determined after ultrafiltration (10 kDa) to exclude the contribution of colloidal particles. In the pH range of 8-9, which is relevant to the KURT-DB3 groundwater condition, the measured dissolved Am(III) concentrations were converged to around 10-8 M. These values are higher than the solubility of AmCO3OH:0.5H2O(s), but lower than that of AmCO3OH(am). There was no indication of transformation of the amorphous phase to the crystalline phase in our observation time window.

There is a need to develop a quantitative residual water measurement method to reduce the measurement uncertainty of the amount of residual water inside the canister after the end of vacuum drying. Therefore, a lab-scale vacuum drying apparatus was fabricated and its characteristics were evaluated by performing vacuum drying experiments based on the amount of residual water, vacuum drying experiments based on the surface area of residual water, and vacuum drying experiments based on the energy of residual water using the lab-scale vacuum drying apparatus. As a result of the vacuum drying experiments, if the surface area of water is the same, the greater the amount of water, the greater the energy of the water, so more energy is transferred to the surface of the water. Therefore, more water evaporated, and the average temperature of the remaining water was higher. The larger the surface area of the water, the more energy it takes to vaporize it, so the faster it dries and the faster the drying time. Before ice formed, energy was actively transferred by conduction heat transfer from the top, center, and bottom of the water to provide the energy needed for the water to evaporate from the surface. However, no energy was transferred from the water just before it turned into ice. When vacuum drying water, you can dry more water if you dry it slowly over a longer period of time. Therefore, by using a vacuum pump with a low flow rate, the pressure can be lowered slowly to prevent ice from freezing, thereby improving the drying quantity. It was evaluated that there was a good agreement between the energy used when water evaporated and the energy absorbed from the surroundings to within about 4%. Therefore, if the energy absorbed from the surroundings is known, it is possible to evaluate the amount of water evaporated in vacuum drying.

Screws are the closest and most familiar mechanical elements of everyday life, and are generally used so widely that there is no machine without screws. Screws are used to make it easier to combine objects with objects, and are also used to transfer large forces from machines. The most influential factor in the coupling of these screws is the effective diameter. If the effective diameter is not accurate, the support cannot be finished or endured, leading to a major accident. The importance of these screws cannot be ignored, so in this study, the effective diameter was measured using the three-wire method, the screw micrometer method, and the projector method, and the one-way factor design method was applied to determine the exact method compared to the KS standard.

In this study, molten salt experiments were performed using a multi-purpose molten salt experimental loop to evaluate the corrosion and thermodynamic properties of the molten salt. The multi-purpose molten salt experimental loop is made of 1-inch austenitic 316 stainless steel, and 1/4-inch austenitic 316 stainless steel tubes were welded on the surface of a 1-inch pipe to measure temperatures of molten salt. During the experiment, the molten salt leaked due to corrosion of the welded part of the 1/4-inch tube connected to the 1-inch pipe. Therefore, the cause of corrosion damage of the leaked welded part was analyzed. The effect of NaCl-MgCl2 salt selected as the molten salt on corrosion failure was considered. And based on the operation data of molten salt experiments, the time of occurrence of the issue was estimated. Lastly, the cause of corrosion failure was estimated by comparing and analyzing the pipe shape before and after failure using SEM-EDS.

The Pacific giant octopus (Enteroctopus dofleini) is one of the most important species in the East Sea fishery of Korea. The annual production of Pacific giant octopus in 2021 was 3,880 metric ton between Gangwon province and Gyeongsangbuk province. Most of the fishing gears for the octopus fishery were based on behavioral properties such as thigmotaxis and chemotaxis. Wooden octopus box is also one of the fishing gears, which is application of thigmotaxis for the octopus capture in fishing industry. In this study, the tank experiments were designed to examine the behaviour and the effect of surface roughness to the infiltration of the octopus quantitatively. Three different types of octopus boxes were used for the experiments with different surface roughness on the average of 701.6 ㎛, 141.7 ㎛ and 2.09 ㎛ for each gear. 22 trials were conducted from June to September 2021. The normality of the experiments was tested using Shapiro-Wilk normality test (p-value < 0.05). The significance of results was conducted by Kruskal-Wallis rank sum test (Chi-squarded = 21, Degree of freedom = 3, p-value < 0.05). The use of wooden octopus box with rough surface was found to enhance the catch efficiency and observe infiltration behaviour of the octopus frequently.