본 연구는 국내산 목재의 효율적인 이용과 이용확대를 목표로, 낙엽송, 소나무 그리고 백합나무의 도장처리에 따른 흡수성과 방사방향 및 접선방향 의 고습환경하의 팽윤율을 조사하였다. 도장처리재는 미처리재에 비해 3수종 모두 고습환경에 노출 된 후 150시간 이후의 흡수율은 작게 나타났고, 도장처리재의 흡수율은 백합나무(2.2%) > 소나무(2.1%) > 낙엽송(1.9%)의 순이었다. 고습환경에 노출된 후 150시간 이후의 함수율은 흡습량에 비례하여 증가하였고, 그 크기는 백합나무 > 낙엽송 > 소나무의 순이었으나, 소나무의 경우 양자의 차이가 적은 것이 확인되었다. 도장처리재의 방사방향 팽윤율은 2.18% - 3.44%의 범위였고, 그 크기는 낙엽송이 백합나무나 소나무에 비해 현저히 적은 값을 나타내었다. 또한, 도장처리재의 접선방향 팽윤율은 4.17% - 6.36%의 범위에 있었고, 이 값은 방사방향과 같이 낙엽송이 가장 적었고, 소나무, 백합나무의 순이었다. 이 값은 미처리재에 비하여 0.85 – 0.96배의 적은 값을 나타내었고, 방사방향의 약 1.9배 높은 값을 나타내는 것이 확인되었다.

Recently marine accidents involving floating objects have been continuously increasing due to domestic coastal traffic conditions, and as a result cases of secondary-linked reduction gear damage have also occurred one after another. This research aims to evaluate the ship propulsion system safety through the analysis the effect of the torsional stress generated on the propeller shaft system when a rope or net is wrapped around a propeller at sea through theoretical analysis, simulation analysis, and ship empirical test.

지구온난화 문제에 대응하기 위해 온실가스 배출 저감을 위한 다양한 규제와 정책이 시행되고 있다. 이러한 배경 속에서 탄소중립을 목표로 하는 국가들이 늘어나고 있으며, 이에 따라 소형원자로모듈(Small Modular Reactor 이하 SMR)이 새로운 발전소 모델 로 주목받고 있다. SMR은 전통적인 대형 원자력 발전소 크기의 5~10% 수준이지만, 수백 메가와트(MW)급의 발전 용량을 갖춘 고효율 시스템이다. 이 발전소는 화석 연료 기반 발전소에 비해 탄소 발생을 줄일 수 있으며, 신재생에너지의 불안정한 에너지 공급을 보완할 수 있는 장점이 있다. 하지만, 원자력 발전소는 사고 시 방사선물질 누출의 위험성이 있어 주변 주민의 반대를 받아 왔다. 이러한 문제 를 해결하기 위해 부유식 소형 원자력 발전선이 주목받고 있다. 부유식 소형 원자력 발전소는 해양에 설치되어 부지확보, 인근 거주민 보상, 협의 과정이 간소화되고, 자연재해에 대한 안전성이 높다. 본 연구에서는 SMR 발전선의 파랑 중 예인 안정성을 평가 하였다. 해 상상태 3, 4, 5에서의 운동해석 결과, 해상상태 5 이하에서는 예인하여 목적지까지 이동하는데 필요한 내항성능 기준을 만족시킬 수 있 음을 확인하였다.

In this study, we developed a new electric low-height beds mechanism with a stable driven rack and pinion by analyzing the current state of existing beds development and supplementing shortcomings of the beds. Structural safety is evaluated through Finite-Element-Analysis using a simulation method applying existing elevate system types and a new type. Furthermore, we designed and manufactured a trial bed with increased variable height considering medical instrument standards to use both for home and hospital. The elevation mechanism suggested in this study could be valuable to electric beds development.

The reversible metal electrodeposition (RME) process is used to prepare electrochromic mirrors with reflectivetransparent optical states, by depositing metal particles on transparent conductive substrates. These RME based devices can be used in smart windows to regulate indoor temperatures and light levels, serving dual purposes as lighting elements. Commercialization efforts are focused on achieving large-scale production, long-term durability, and a memory effect that maintains coloration without applied voltage. Enhancing durability has received particular attention, leading to the development of electrochromic mirrors that employ gel electrolytes, which are expected to reduce electrolyte leakage and improve mechanical stability compared to traditional liquid electrolyte devices. The gel electrolytes offer the additional advantage of various colors, by controlling the metal particle size and enabling smoother, denser formations. In this study, we investigated improving the durability of RME devices by adding polyvinyl butyral (PVB) to the liquid electrolyte and optimizing the concentration of PVB. Incorporating 10 % PVB resulted in excellent interfacial properties and superior electrochromic stability, with 92.6 % retention after 1,000 cycles.

The cultural heritage of fortresses is often exposed to external elements, leading to significant damage from stone weathering and natural disasters. However, due to the nature of cultural heritage, dismantling and restoration are often impractical. Therefore, the stability of fortress cultural heritage was evaluated through non-destructive testing. The durability of masonry cultural heritages is greatly influenced by the physical characteristics of the back-fille material. Dynamic characteristics were assessed, and endoscopy was used to inspect internal fillings. Additionally, a finite element analysis model was developed considering the surrounding ground through elastic wave exploration. The analysis showed that the loss of internal fillings in the target cultural heritage site could lead to further deformation in the future, emphasizing the need for careful observation.

Herein, the present work focuses on the effective counter electrode for dye-sensitized solar cells. The bottom–up approach was adapted to synthesize Mn2O3 nanorods via the hydrothermal method and the reduced graphene oxide was merged with Mn2O3 to prepare a nanocomposite. The prepared nanocomposites were subjected to physio-chemical and morphological characterizations which revealed the crystalline nature of Mn2O3 nanorods. The purity level rGO was characterized using the Raman spectrum and the Fourier transform infrared spectroscopy employed to find the functional groups. The morphological micrographs were visualized using SEM and TEM and the high aspect ratio Mn2O3 nanorods were observed with 5–7 nm and supported by rGO sheets. The electrocatalytic nature and corrosion properties of the counter electrode towards the iodide electrolyte were studied using a symmetrical cell. The as-synthesized nanocomposites were introduced as counter electrodes for DSSC and produced 4.11% of photoconversion efficiency with lower charge transfer resistance. The fabricated DSSC devices were undergone for stability tests for indoor and outdoor atmospheres, the DSSC stability showed 93% and 80% respectively for 150 days.

In the present study, the effects of electrodes type (copper, steel or CFRP) and design (plate or mesh) on electrical stability of conductive cement as exposed to various weathering conditions were investigated. To fabricate these composites, multiwalled carbon nanotube and carbon fiber were added to the cement composites by 0.6 and 0.4% by cement mass. Seven different types of electrodes were embedded to the samples, and their electrical stability was examined during the curing period. In addition, the fabricated samples were exposed to water ingress and cyclic heating conditions. Then, the compressive strength of the samples was evaluated to observe the interfacial bonding between the cement paste and electrodes. Based on the experimental results, it was found that the samples showed different electrical stability even their mix proportion was same. Thus, it can be concluded that the type and design of the electrodes are important in measuring the electrical properties of the conductive cement composites. Specifically, an improved electrical stability of electrodes is required when they are exposed to various weathering conditions.

주로 소형어선에서 발생하고 있는 연근해에서의 전복사고를 예방하기 위해 소형어선의 복원성 평가는 중요하다. 하지만 국내 ｢어선법｣에서는 24m 미만의 소형어선에 대한 복원성 평가 규정이 미비한 실정이다. 2022년 해양수산부에서 안전복지를 강화하여 고시한 표준어선형에 관한 안전성 기준에 따르면, 표준어선형을 따르는 선박은 길이와 무관하게 안전성 기준에 따른 복원성을 가져야 한다. 이에 본 연구에서는 상기 기준을 활용하여 24m 미만에 해당하는 4.99톤급 어선에 대한 복원성 평가를 수행하고 해당 기준으로 복원성을 평가 하는 것이 적합한지 검토하는 것을 목표로 한다. 또한 다양한 상부구조물을 가지는 4.99톤급 소형어선에 대해서도 해당 기준이 유효한지 검토를 수행한다. 이를 위해 어선의 초기횡메타센타높이(GM)를 이용한 초기복원성과 한계경사각에서의 복원정(GZα)을 평가하였다. 그리 고 현재 표준어선형의 소형어선에서 주로 활용되는 상부구조물의 형태를 활용하여 대상선과 동일한 하부 선형과 제원을 가지는 소형어 선 6종을 추가로 선정하여 상부구조물 변화에 따른 복원성 변화도 검토하였다. 4.99톤급의 표준어선형을 대상으로 한 연구 결과, 안전복 지를 강화한 표준어선형에 대한 안전성 기준은 4.99톤급 표준어선형의 어선에도 적용 가능하며, 상부구조물에 변화에 따른 복원성 변화는 크지 않은 것으로 확인되었다.

The aim of this study was to improve the chemical stability of cycloserine containing organic and inorganic compounds. Composite particles were manufactured with a 1:1 weight ratio of organic/inorganic compounds and cycloserine. The influence of organic/inorganic compounds on the stability of cycloserine was investigated under accelerated stress conditions at 60°C/75% RH for 24 hours. In addition, the properties of the composite particles were evaluated using differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and the dissolution of the drug was assessed by preparing it as a hard capsule. Among the organic and inorganic compounds investigated, calcium hydroxide most improved the stability of cycloserine under accelerated stress conditions (53.3 ± 2.2% vs 1.7 ± 0.2%). DSC results confirmed the compatibility between calcium hydroxide and the cycloserine, and SEM results confirmed that it was evenly distributed around the cycloserine. Calcium hydroxide also showed more than 90% cycloserine dissolution within 15 minutes. Therefore, the calcium hydroxide and cycloserine composite particles may be candidates for cycloserine oral pharmaceuticals with enhanced drug stability.

The aim of this study is to evaluate the possibility of damage to cultural assets resulting from vibrations generated by construction vehicle traffic. The cultural heritage's natural vibration frequency was determined to be 150Hz by measurement. The damping ratios were calculated as 4.7% using the logarithmic decrement approach and 4.3% using the half-power method. The vibration measurements obtained during vehicle operation indicated that, despite an increase in vehicle velocity of up to 15 km/h, the vibrations remained below the detectable level of 0.13 mm/sec. When the road is curved and the terrain is sloped, a suitable speed for vehicle operation was found to be around 17 km/h, at which point vibrations were seen. The highest recorded vibration amplitude at this velocity was 0.217 mm/sec, which remains below the stringent regulation limit of 2 mm/sec. Thus, it can be concluded that there is no actual harm caused by vibrations.

Black soldier fly (BSF, Hermetia illucens) has been noted as an excellent feed ingredient. However, there is limited information on rearing and processing technology. Thus, this study was conducted to evaluate the substrates for rearing BSF and the optimal processing method for BSF performance. Study separated as 2 experiment, BSF rearing and drying method(Exp 1.) and EP-processing method(exp 2.). During the study, 30 clutches were reared, with 10 per substrate. Three substrates, namely food waste (FW), tofu by-product (TF), and vegetable waste with two drying methods, namely hot air dry (AD) and microwave dry (MW) at expanding (EP) ratios of 5:5 and 7:3, were examined by evaluating their rearing performance, nutrient contents, in vitro digestibility and lipid oxidation stability during storage (0, 14 and 28 days). In experiment 1, the rearing substrates and drying methods were evaluated. Compared with that of conventional methods (FW, AD), the TF substrates and MW method showed higher dry matter contents (3.43%) and in vitro digestibility (1.62%) but lower ether extract contents(3.53%; p<0.05). However, the malondialdehyde (MDA) concentration under MW treatments decreased during storage (5.77%, 4.69% and 3.24%; p<0.05). In experiment 2, compared with that of the 7:3 EP-BSF ratio, the 5:5 EP-BSF ratio showed higher in vitro digestibility (2.70%) and lower MDA concentration during storage (19.19%, 7.96% and 6.42%; p<0.05). In conclusion, the optimal conditions for BSF rearing and ensuring product quality were TF substrates, MW methods and a 5:5 corn:BSF ratio. Therefore, the optimal conditions for producing EP-BSF can present an excellent feed ingredient alternative for swine feed.

Effects of glutamic acid (Glu) and monosodium glutamate (MSG) on oxidative stability of oil-in-water (O/W) emulsions with different emulsifier charges during riboflavin (RF) photosensitization were evaluated by analyzing headspace oxygen content and conjugated dienes. Cetyltrimethylammonium bromide (CTAB), Tween 20, and sodium dodecyl sulfate (SDS) were used as cationic, neutral, and anionic emulsifiers, respectively. Glu acted as an antioxidant in CTAB- and Tween-20-stabilized O/W emulsions during RF sensitization, whereas Glu acted as prooxidants in SDS-stabilized O/W emulsions in the dark. However, adding MSG did not have a constant impact on the degree of oxidation in O/W emulsions irrespective of the emulsifier charge. In RF-photosensitized O/W emulsions, the emulsifier charge had a greater influence on antioxidant properties of Glu than on those of MSG.