병원성대장균은 설사 및 장염의 원인균 중 하나이며, 가 장 흔한 기회감염의 병원체로서 내성에 대한 지표로도 사 용되고 있는 병원체이다. 2022년부터 2024년까지 경상남 도 내 식중독 환자로부터 분리된 병원성대장균의 병원성 유형, 독성 유전자, 항생제 내성 및 내성 유전자 등 발생 경향과 분자유전학적 특성을 조사하였다. 병원성 대장균 은 월별로 6월부터 8월까지, 연령대별로 20-29세 환자에게서 가장 많이 분리된 것으로 나타났다. 분리된 총 283 건의 병원성대장균은 장병원성대장균(EPEC)(118건 [43.7%]), 장독소형대장균(ETEC)(80건 [28.3%]), 장출혈성대장균 (EAEC)(73건 [25.8%]), 장출혈성대장균(EHEC)(11건 [3.9%]) 으로 분류됐다. 암피실린(57.6%)과 세파졸린(39.3%)에 대 한 내성이 가장 높았으며, 내성균주의 다제내성률은 4제 항생제에 대한 내성균주(42.6%)가 가장 많은 것으로 확인 되었다. 내성 유전자의 분포는 blaCTX-M(48.9%), blaTEM (24.9%) 순으로 확인되었고, blaOXA는 검출되지 않았다. 이러한 연구 결과는 병원성 대장균으로 인한 식중독 발생 을 예측하고, 내성균 확산을 예방하기 위한 공중 보건 관 리의 기초자료로 활용될 수 있을 것으로 기대된다.

This study evaluates the applicability of mastic asphalt concrete for backfilling mini-trenches of communication cables. Characterization tests, such as the dynamic modulus, flow-number, Texas overlay, four-point bending beam, and Hamburg wheel tracking tests, were conducted on conventional mastic asphalt concrete and lower-temperature mastic asphalt concrete. A structural analysis of the backfilling of mini-trenches of mastic asphalt concrete was performed and compared with the results of conventional soil backfilling methods using the finite-element method. The performance year was calculated based on the strain behavior and the results of the structural analysis. A life-cycle cost analysis (LCCA) was performed based on net-present-value method. The results of laboratory experiments show that the lower-temperature mastic asphalt concrete performs better than conventional mastic asphalt concrete in terms of resistance to permanent deformation and fatigue cracking. The performance year of the mastic asphalt concrete is three times longer than that of the conventional sand-backfilling mini-trench. The LCCA results indicate that the cost of backfilling by the mastic asphalt concrete is two times lower than that by the conventional sand-backfilling mini-trench.

Ecological indicators are tools used to evaluate the state of specific environments by monitoring the ecological characteristics and changes of organisms, and they are widely utilized in environmental monitoring and management. Such indicators should be sensitive to environmental changes, maintain long-term stability, and be easy to investigate and analyze. This study aimed to evaluate whether the spraint density of the Eurasian otter (Lutra lutra) can monitor the state and changes in river ecosystems. Using spraint density data over nine years (2014~2024), we analyzed temporal and spatial changes in otter distribution. Generalized Additive Models were applied to assess annual variability, and spatial clustering and distribution changes were examined using Hotspot Analysis and Geo-SOM (Geo-Self-Organizing Map). The results indicated stable spraint density trends in most sub-watersheds, with higher variability in developed areas. This study highlights the potential of spraint density as a cost-effective and simple ecoological indicator for long-term river ecosystem monitoring.

This study aims to prepare bamboo-based activated carbons with surface modifications, focusing on carbon dioxide (CO2) capture in public indoor spaces. The surface of the activated carbon adsorbents was chemically modified through three steps: carbonization, steam activation, and chemical treatment using potassium hydroxide (KOH) and potassium sulfamate (KSO3NH2). The specific surface area and pore volume of the obtained adsorbent (BSAC-KN) were 1,246 m2/g and 0.74 cm3/g, respectively. The surface modification resulted in an adsorption capacity of up to 3.79 mmol-CO2/ g-AC for carbon dioxide. In addition, the expansion of the specific surface area and the enhanced physico-chemical interaction between the weak acidic CO2 molecules and the basic AC surface improved adsorption capacity.

This study is about the evaluation for shock-proof performance of the system, elastically support the low accumulator of the naval artillery against underwater explosion, using DDAM. For the evaluation, the shock analysis procedure using DDAM, supported by MSC/NASTRAN, was briefly described. In addition, in order to perform the shock analysis, the elastic support system was modeled as a finite element. The shock analysis of the elastic support system was performed by selecting the analysis frequency range so that reliable results can be obtained. Finally, the shock-proof performance of the system was evaluated by comparing the shock analysis results with the properties of the elastic support system.

Due to the rapid advancements in power distribution, television, and telecommunication, aerial cables have been rampant in urban cities. Aerial cables, while cost-effective, contribute to visual pollution, pose safety hazards, and complicate urban planning. To solve these challenges, many cities are exploring new ways to construct these cables without the use of high poles and one of the solutions is transitioning to underground cable by minitrenching method. Minitrenching offers a less invasive, more efficient solution for underground cable deployment. This study highlights the potential of innovative minitrenching materials to enhance underground cable protection while addressing the limitations of aerial cable installations in urban settings. Three minitrenching materials were evaluated to determine their effectiveness in protecting underground cables from heavy truck loads using finite element method (FEM). The materials tested were: (1) sand backfill with asphalt concrete surface, (2) cement mortar backfill with self-compacting mastic asphalt surface, and (3) cement mortar backfill with asphalt concrete surface. Results showed that the proposed materials (cement mortar and self-compacting mastic asphalt) significantly reduced strain on the underground cable compared to traditional materials (sand and asphalt concrete). The strain values decreased from 713 microstrains with traditional materials to 333 microstrains with the proposed materials, representing a reduction of approximately 53%. The third combination, intended as a maintenance material, yielded an intermediate strain value of 413 microstrains, demonstrating its acceptability as a minitrenching material.

This study is about the design of an elastic support system to isolate the structural noise of the low accumulator of the naval artillery among the equipment mounted on a warship. As the structural noise measurement value of the low accumulator transmitted to the ship exceeded the standard value, a method of applying an elastic mount between the equipment and the ship was devised to isolate the structural noise. By calculating the target vibration isolation efficiency, the vibration isolating system was designed in consideration of design factors such as the system's natural frequency and static displacement. Finally, the performance of the structural noise reduction of the designed vibration isolating system was verified by evaluating the structural noise transmitted to the foundation plate of the equipment from the low accumulator to which designed elastic support system was applied.

This study analyzed the influence of ball size and process control agents on the refinement and dehydrogenation behavior of TiH2 powder. Powders milled using ZrO2 balls with diameters of 0.1 mm, 0.3 mm, and 0.3+0.5+1 mm exhibited a bimodal particle size distribution, of which the first mode had the smallest size of 0.23 μm for the 0.3 mm balls. Using ethanol and/or stearic acid as process control agents was effective in particle refinement. Thermogravimetric analysis showed that dehydrogenation of the milled powder started at a relatively low temperature compared to the raw powder, which is interpreted to have resulted from a decrease in particle size and an increase in defects. The dehydrogenation kinetics of the TiH2 powder were evaluated by the magnitude of peak shift with heating rates using thermogravimetric analysis. The activation energy of the dehydrogenation reaction, calculated from the slope of the Kissinger plot, was measured to be 228.6 kJ/mol for the raw powder and 194.5 kJ/mol for the milled powder. TEM analysis revealed that both the milled and dehydrogenated powders showed an angular shape with a size of about 200 nm.

In this paper, the cause of mortar baseplate breakage was analyzed by diving into cross-section, material, process, and design aspects. As a result of observing the fracture surface and non-fracture suface using optical equipment, it was possible to confirm changes in the shape of disconnected line and metal surface at a specific area. In addition, a number of linear defects due to overlap were found. Flow analysis was performed using the Deform program to verify changes during the production process. According to the result, a drop test was performed on each of the lap detection baseplate, undetection baseplate, and removed product to verify the presumptive cause of the rupture of the poplite.

하수기반역학을 이용한 코로나19 감시 결과, 연구기간 (2022년 8월-2023년 8월)동안 울산지역 4곳 하수처리장의 전체 174건 모든 시료에서 코로나바이러스-19가 검출되었 다. 확진자 수와 하수 내 코로나바이러스 농도와의 상관 분석 결과, 높은 상관성이 나타났으며 특히 하수감시가 임 상감시보다 2-3주 앞서 농도가 증가함으로써 조기 인지의 가능성도 볼 수 있었다. 또한 코로나19 변이 분석 결과 역 시 유행 시기별 우세종화된 변이와 비교적 유사하여 변이 예측도 가능하였다. 하수감시가 전국적, 전세계적으로 적용되고 있으며 많은 연구가 국가적 사업으로 진행되고 있 다. 이에 따라, 하수 분석방법 및 분석기기 발전 등의 지 속적 연구 업데이트가 필요하다. 또한 코로나19를 통해 감 염병의 선제적 모니터링 및 유행 예측의 가능성을 확인하 였으므로 다양한 병원체 및 식품·의약품 등에 확대 적용 이 진행 중이다. 따라서 본 연구는 감염병 검출분야에서 더 나아가 하수 내 식품 성분, 활성물질 및 미생물 등의 분석을 통해 지역사회의 식품안전 및 전반적인 위생환경 감시를 위해 활용될 수 있을 것으로 기대된다.

본 논문에서는 조선 후기의 대표적인 전통목구조인 수원 화령전 운한각의 구조성능을 평가하였다. 운한각의 가구구성 방식에 맞추 어 3차원 구조해석 소프트웨어인 midas Gen으로 해석모델을 정교하게 구축하였다. 정적해석으로 주요 구조부재의 안전성과 사용성 을 평가하였고, 고유치해석으로 동적거동특성을 평가하였다. 대부분의 부재가 안전성 및 사용성 기준을 여유 있게 만족하고 있으나, 외목도리에서 휨응력비가 기준을 20.7% 초과하고 있어 이 부재에 대해서는 장기적인 모니터링이 필요하다고 사료된다. 운한각의 고 유주기는 1.079초로 비슷한 규모의 전통목구조보다 약간 긴 편이며, 특히 후면 화방벽의 영향으로 2차모드에서 비틀림이 발생한 것으 로 분석된다.