In this study, anatase TiO2 nano sol (TNS, TiO2 Nano-Sol) was synthesized via a simple sol-gel method under low-temperature and ambient pressure conditions using TiOCl2 as a precursor. The structural and photocatalytic properties of the TNS were systematically investigated as a function of reaction time. X-ray diffraction (XRD) confirmed the formation of the anatase crystal structure as the reaction time increased, while field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) analyses verified the uniform formation of fine anatase nanoparticles, averaging less than 10 nm in size. The synthesized TNS sol enabled the fabrication of transparent TiO2 coatings that retained over 76 % transmittance in the visible light range, as verified by UV-Vis spectroscopy. Photocatalytic activity was evaluated through methylene blue (MB) degradation experiments, which showed that degradation efficiency was enhanced with longer reaction times. Notably, the TNS-48 exhibited superior photocatalytic degradation performance, being approximately three times higher than that of TNS-1 and about twice that of the commercial P25. This study demonstrates that the TNS sol synthesized through a simple sol-gel process can achieve high transparency and excellent photocatalytic properties without requiring hightemperature and high-pressure synthesis. It is expected to be applicable in various photocatalytic fields, such as functional coatings and electrode materials.

Hydrogen has a wide flammability range and rapidly diffuses in air, making precision detection technology essential to prevent explosion risks and ensure system safety as the adoption of hydrogen infrastructure expands. Polymer materials are employed in such infrastructure to seal high-pressure hydrogen, and reliable measurement techniques capable of quantifying trace amounts of hydrogen permeating or leaking through these materials is necessary. In this study, a hydrogen quantification system combining volumetric analysis with image analysis was utilized to evaluate the hydrogen uptake and diffusivity of HDPE (high-density polyethylene), NBR (nitrile butadiene rubber), and EPDM (ethylene propylene diene monomer) under high-pressure conditions. The results indicated that HDPE and NBR samples containing silica filler exhibited hydrogen uptake behavior consistent with Henry’s law, while EPDM samples with carbon black filler demonstrated additional hydrogen adsorption on the carbon black surface. These research results provide a foundation for more precisely evaluating the permeation and leakage behavior of polymers in high-pressure hydrogen environments, and are expected to contribute to the safe and efficient development of hydrogen infrastructure.

This study determined the appropriate pressure for high pressure shucking of oysters (Magallana gigas) according to size categories. One-year and two-year-old oysters harvested from Yeosu and Tongyeong coastal areas were subjected to high pressure treatments with pressure ranging from 180 to 240 MPa and holding times of 0 to 420 seconds. Results demonstrated that 100% shucking rates were achieved at 220 MPa with 120-180 seconds holding time regardless of harvest time and production area. K-means cluster analysis was used to classify oyster specimens into small, medium, and large size groups with mean shell heights of 69.0 mm, 86.6 mm, and 106.7 mm, respectively. The analysis revealed that shucking efficiency improved directly proportional to oyster size. However, the appropriate shucking pressures converged at approximately 220 MPa for all size groups, with small, medium, and large groups showing 218.9 MPa, 221.7 MPa, and 220.6 MPa, respectively, and no significant differences among groups. These findings suggest that the appropriate pressure for high pressure shucking processes be approximately 220 MPa regardless of harvest time and production area, providing foundational data for potential automation of oyster shucking processes.

본 연구는 병원성 박테리아 Agrobacterium rhizogenes에 대해 저압 수은 UV-C 소독 시스템의 살균 성능을 정량적으로 평가하고, 램프 소비전력과 유량의 조합에 따른 소독 효율에 미치는 영향을 분석하였다. 농업용수는 경상남도 사천시 소 재 세 농가(A, B, C)와 함안군 군북면의 한 농가(D)에서 채취 하였으며, 목표 병원균을 인위적으로 접종한 뒤 실험을 수행 하였다. 실험은 1차와 2차로 구분되며, 1차 실험은 소비전력 40, 75, 105W와 유량 10, 15, 30L/min의 3×3 조합으로 구성 되었고, 2차 실험은 소비전력 75W 조건 하에서 고유량(60, 120L/min) 조건을 적용하였다. 대부분의 실험 조건에서 박테 리아가 완전히 사멸되었으며, 유일하게 생균이 검출된 조건 (#33, 75W－60L/min)에서만 생균이 검출되었다. 그러나 해 당 조건에서도 생균수는 UV 비처리 대조군(#37)에 비해 약 4.9log 수준 감소하여 유의미한 소독 효과가 확인되었다. 이 러한 결과는 고유량 조건에서도 충분한 UV 조사량이 확보된 다면 안정적인 소독이 가능함을 시사한다. 본 연구는 저압 UV-C 시스템의 운전 변수에 따라 살균 효율이 어떻게 달라지 는지를 실험적으로 입증하였으며, 농업용수 처리에 있어 해 당 기술의 실용적 적용 가능성을 제시하였다.

A high-pressure in-situ permeation measuring system was developed to evaluate the hydrogen permeation properties of polymer sealing materials in hydrogen environments up to 100 MPa. This system employs the manometric method, utilizing a compact and portable manometer to measure the permeated hydrogen over time, following high-pressure hydrogen injection. By utilizing a self-developed permeation-diffusion analysis program, this system enables precise evaluation of permeation properties, including permeability, diffusivity and solubility. To apply the developed system to high-pressure hydrogen permeation tests, the hydrogen permeation properties of ethylene propylene diene monomer (EPDM) materials containing silica fillers, specifically designed for gas seal in high-pressure hydrogen environments, were evaluated. The permeation measurements were conducted under pressure conditions ranging from 5 MPa to 90 MPa. The results showed that as pressure increased, hydrogen permeability and diffusivity decreased, while solubility remained constant regardless of pressure. Finally, the reliability of this system was confirmed through uncertainty analysis of the permeation measurements, with all results falling within an uncertainty of 11.2 %.

Background: Stroke often results in hemiparesis, which leads to asymmetrical plantar pressure and impaired balance control. The gastrocnemius muscle plays a key role in plantar flexion and postural stability. Dysfuncion of this muscle is associated with decreased posterior foot pressure and increased fall risk in stroke patients. Objectives: To investigate the effects of gastrocnemius muscle stimulation using microcurrent stimulation therapy on plantar pressure distribution and functional balance in stroke patients. Design: Randomized controlled trial. Methods: Twenty chronic stroke patients were divided into an experimental group (microcurrent stimulation therapy+conventional rehabilitation therapy) and a control group (conventional rehabilitation therapy only). plantar pressure (posterior foot pressure), center of anteroposterior pressure displacement (CAP), and balance ability were measured using the berg balance scale (BBS) and functional reach test (FRT) before and after 8 weeks of intervention. Results: The experimental group showed statistically significant increases in posterior foot pressure and reductions in CAP after intervention. BBS and FRT scores also significantly improved. Although the control group showed some improvements, the changes were smaller and less consistent. Conclusion: Microcurrent stimulation targeting the gastrocnemius muscle improved plantar pressure symmetry and postural stability in stroke patients, suggesting its effectiveness as an adjunctive balance rehabilitation intervention.

This study examined how perceived scarcity influences consumer purchase decisions in the context of preorder fashion, with a focus on the mediating role of purchase pressure and the moderating role of hedonic shopping value. A survey was conducted with 300 consumers who had previously purchased fashion products through preorder platforms in Korea. The key constructs –limited time/quantity scarcity, product scarcity, time pressure, financial pressure, purchase delay, purchase intention, and compulsive buying– were validated using exploratory and confirmatory factor analysis. Structural equation modeling showed that perceived scarcity significantly increased purchase pressure. Specifically, limited time/quantity scarcity heightened time pressure, while product scarcity heightened both time and financial pressure. In turn, time pressure positively influenced both purchase intention and compulsive buying, whereas financial pressure led to increased purchase delay. Mediation analysis confirmed that time pressure fully mediated the relationship between limited time/quantity scarcity and both purchase intention and compulsive buying, while product scarcity exerted both direct and indirect effects, particularly on compulsive buying. A multigroup analysis further revealed that hedonic shopping value did not moderate the overall structural model but had significant effects on specific paths. Consumers with high hedonic shopping value were more sensitive to product scarcity and experienced greater purchase pressure than those with low hedonic shopping value. These findings offer valuable insights for marketers who employ scarcity tactics in preorder strategies and highlight the importance of psychological mechanisms in shaping consumer behavior. Theoretical implications and future research directions are also discussed.

길이가 긴 터널 내부에서 TNT와 같은 화약의 폭발을 해석할 때, 재연소 현상을 고려하는 것이 매우 중요하다. 재연소 현상을 해석 에 반영하기 위해서는 재연소 에너지와 지속 시간을 적절히 적용해야 한다. 본 연구에서는 터널과 유사한 구조인 충격파관 실험을 통 해 해석 조건을 검증한 뒤, 이를 바탕으로 터널 입구로부터 내부 폭발 위치 변화에 따른 재연소 지속 시간의 경향을 분석하였다. 또한, 이 결과를 폭발 해석에 적용하여 터널 내부 폭압과 충격량의 변화를 분석하였다. 해석은 입구 면적이 0.785m2인 정사각형 단면의 터 널을 모델링하여 수행되었다. 분석 결과, 터널 내부 폭발 위치가 입구에서 깊어질수록 재연소 지속 시간은 일정하게 증가하며 특정 지 점에서 수렴하는 경향을 보였다. 또한, 재연소 지속 시간 증가를 반영한 폭발 해석 결과, 터널 내부 최대 폭압은 폭발 위치가 내부로 이 동함에 따라 증가하다가 특정 폭발 위치 이후로는 더 이상 증가하지 않았다.

원전에서 발생 가능한 중대사고 중 하나인 용융 노심-콘크리트 상호작용(Molten Core Concrete Interaction, MCCI)은 노심의 용융물이 격납용기 하부의 콘크리트를 침투하면서 콘크리트의 물리적 및 화학적 분해를 유도하고, 이로 인해 구조적 손상이 발생하게 된다. 더불어, 분해 과정에서 발생하는 비응축성 가스와 수증기로 인해 내부압력이 급격히 상승할 수 있다. 본 연구는 MCCI 가 발생하는 상황에서 원전 프리스트레스트 콘크리트 격납용기(Prestressed Concrete Containment Vessel, PCCV)의 내부압력 저 항능력을 평가하는 것을 목적으로 한다. 이를 위해 APR1400을 대상으로 MELCOR 코드 기반의 사고 시나리오를 통해 압력 및 온도 상승을 모사하였으며, 검증된 유한요소 해석모델을 이용해 구조응답을 분석하였다. 내부압력 저항능력은 글로벌 후프 변형률(global hoop strain)과 등가소성변형률(equivalent plastic strain) 두 가지 한계상태 기준에 따라 비교 분석하였다.

Background: Recent research suggests that the most effective and proactive method for correcting excessive pronation, which contributes to the lowering of the medial longitudinal arch, is to enhance both intrinsic and extrinsic foot muscles simultaneously. Objectives: This study aims to compare the effects of intrinsic and extrinsic foot muscle exercises on medial longitudinal arch height, plantar pressure distribution, and lactate levels in university students with flexible flatfoot. Design: Randomized controlled trial study. Methods: Twenty-two students with flexible flat foot participated in this study and were recruited by N University in Korea. The subjects were randomly divided into Intrinsic foot muscle strengthening group (IFG; n=11) that went through Intrinsic foot muscle strengthening exercise, Extrinsic foot muscle strengthening group (EFG; n=11) that went through extrinsic foot muscle strengthening exercise. SPSS was used for statistical analysis. Results: Both groups showed significant increases in medial arch height and first metatarsal bone pressure, while EFG also had increased pressure at the second to fourth metatarsal bones. No significant differences were found in lactate levels. Conclusion: Both intrinsic and extrinsic foot muscle strengthening exercises can be suggested as effective interventions for improving medial longitudinal arch height and plantar pressure.

Damage to masonry walls can occur for various factors. It is often believed that heavy rains and increased rainfall cause soil and sand to flow into the stone masonry walls, leading to this damage. However, no research has definitively proven or analyzed this causal relationship.This study aims to evaluate the causes of damage to masonry walls due to severe rainfall and to propose preventive strategies to mitigate future risks. The assessment found that, as a form of cultural heritage, the stone masonry walls did not exhibit any structural or material issues that could compromise their stability. However, concerns were raised about potential problems arising from hydraulic pressure due to rising groundwater levels. Calculations and computer simulations confirmed that the risk of collapse increases with higher groundwater levels. Therefore, it is essential to carry out repairs and reinforcements to prevent a recurrence of this situation.

이 연구는 다목적 선박(MPV)의 공기역학적 구조물 설계, 분석 및 향상을 통해 그린 워터 압력에 의한 구조적 안전을 보장하고, 탈탄소화 및 에너지 효율성에 이바지하는 방법을 기술하였다. 유한 요소 분석(FEA)을 통한 초기 평가에서 좌굴 발생에 대한 잠재적인 취약점 이 있음을 확인하였다. 이러한 문제를 해결하기 위해 보강재(Carling stiffener)와 두께 증가를 통하여 응력을 재분배하고 국부적인 좌굴 발생의 위험을 최소화하였다. 보강 후 분석 결과, 한국선급(KR)의 안전 기준인 항복 강도, 미국 선급(ABS) 좌굴 강도 및 노르웨이 표준(NORSOK) 변 위 기준을 모두 충족하는 것이 확인되었다. 결과적으로 고유치 좌굴 해석 결과가 안전 기준을 초과하고 최대 변위가 허용 한계 내에 있는 등 중요한 개선이 이루어졌다. 이러한 개선은 극한의 해양 조건에서 운영 신뢰성을 보장할 수 있다. 이 연구는 공기역학적 항력 감소와 구조적 안전성의 이중적인 이점을 강조하며, 국제 해사 기구(IMO)의 2050 탈탄소화 목표에 부합하는 연료 효율성 및 온실가스 배출 감소에 이바지할 수 있다. 연구 결과는 다양한 선박 유형에 걸쳐 항력 감소 기술을 확장하기 위한 기초 자료를 제공하며, 지속 가능하고 탄력적인 해양 운영을 위한 대안을 제시하였다. 향후 연구는 구조적 안전 평가를 가속할 수 있는 단순화된 모델링 기술 개발에 집중할 것이다.

This study investigated the effects of different emulsification techniques—high-pressure homogenization (HPH) and ultrasonic homogenization (USH)—on the properties of β-glucan-loaded liposomes under varying operational conditions. The results showed that, in HPH, increasing both the pressure (5,000–15,000 psi) and the number of cycles (1–3) gradually reduced the average particle size of the liposomes, with all particles remaining below 200 nm and a polydispersity index (PDI) under 0.1, with no significant differences (p>0.05). Liposomes produced with USH at the lowest energy level (20% amplitude for 1 min) exhibited the largest average particle size (594.63 nm) and greatest size variation. However, increasing the power and duration of USH reduced both the liposome size and PDI, making them comparable to those produced by HPH. Turbidity improved with increasing energy in both methods (p<0.05), although the turbidity ranges differed: HPH ranged 0.243–0.839 and USH, 0.628–1.715. Overall, this study demonstrates that HPH is more effective than USH in producing stable β-glucan liposomes.

Background: Hallux valgus (HV) is a common foot deformity in which the great toe deviates laterally and the first metatarsal deviates medially, leading to pain, discomfort, and reduced mobility. HV severity is typically assessed using the hallux valgus angle (HVA) and intermetatarsal angle (IMA). Objects: This study aimed to explore how changes in skeletal, muscular, and functional variables correlate with HV severity and to provide evidence for more integrated treatment approaches. Methods: Sixty volunteers with mild to moderate bilateral HV (HVA 15–40 degrees) participated. The measurements included HVA and IMA via radiography, abductor hallucis muscle (AbdH) cross-sectional area (CSA) and tone using ultrasound and Myoton PRO, range of motion (ROM) of the ankle and great toe metatarsophalangeal (MTP) joint with a goniometer, and plantar pressure during gait with a Zebris FDM system. Pearson’s correlation coefficient was used for the statistical analysis. Results: An Increased HVA was associated with a higher IMA (r = 0.858, p < 0.05). The HVA was inversely related to the AbdH CSA (r = –0.337, p < 0.05) and muscle tone (r = –0.889, p < 0.01). With increasing HVA, dorsiflexion ROM of the ankle (r = –0.307, p < 0.01) and both flexion (r = –0.197, p < 0.05) and extension (r=-0.182, p<0.05) ROM of the great toe MTP joint decreased. Conversely, ankle plantar flexion ROM increased with the HVA (r = 0.312, p < 0.01). Additionally, plantar pressure increased in the second metatarsal areas (r = 0.457, p < 0.05) a with higher HVA. Conclusion: This study demonstrates significant correlations between HV severity and various biomechanical factors, highlighting the need for comprehensive treatment strategies. While stretching the adductor hallucis muscle and strengthening the AbdH have been widely recognized interventions for HV, our findings provide evidence that ROM exercises for the ankle and the MTP joint of the great toe are also critical components of a physical therapy program for managing HV. Longitudinal studies are required to assess the effectiveness of these approaches.