513 magnesium hydroxide sulfate hydrate (MHSH) and Mg(OH)₂ were synthesized by controlling the pH and concentration using a domestic resource, dolomite (CaMg(CO3)2), as the raw material. The MgSO₄ was extracted by treating dolomite with sulfuric acid under various conditions. Hexagonal plate-shaped Mg(OH)₂ and needle-like 513 MHSH were synthesized under the hydrothermal condition. The morphology of the synthesized materials was controlled by adjusting the pH (SO42-/OH- ratio) and hydrothermal reaction time. As the pH of the solution increased, the formation of plate-like structures became dominant, whereas lower pH values (higher SO42- concentration) led to needle-like forms. The results of the 513 MHSH, which was synthesized using reagents and sea bittern, are consistent with the synthesis conditions, and we observed changes in the length and aspect ratio of the needle-shaped structure in response to adjusting the hydrothermal reaction time.

Background: This study aimed to investigate the relationship between occupational conditions and foot morphology in industrial workers. Objects: A total of 118 workers from Cheonan and South Korea were recruited through a manufacturing plant for participation in this study. Methods: Musculoskeletal findings were evaluated by musculoskeletal symptoms disease questionnaire. We measured foot structure and foot plantar pressure-based variables using the Arch Finder System. Pearson’s correlation analysis was used to investigate statistical examination. Results: Longer years of service revealed a weak negative correlation with foot width, medial arch height, and metatarsal width; workers with foot pain and laborious positions record high values of plantar pressure than those in office positions. Furthermore, strong bilateral correlations were observed between the foot morphological structure parameters of participants (r = 0.796–0.890). Conclusion: Occupational conditions, particularly duty duration and job type, influence plantar pressure and foot structure. Plantar pressure assessment may aid in the early identification and prevention of work-related musculoskeletal disorders.

This study investigates how lake morphology, water quality, and water-level fluctuations (WLF) collectively shape wetland plant communities across 90 lakes in the Republic of Korea. By analyzing morphological indices (Index of Basin Permanence; IBP, Rawson Index; RI), WLF, water quality, and vegetation data, we identified four distinct lake groups through cluster analysis. Group C, comprising large dams, was characterized by the highest IBP and extreme WLF. Despite having favorable water quality, this group exhibited the lowest species richness, suggesting that severe physical disturbance from WLF is a primary limiting factor for wetland plant community. In contrast, Group A (estuarine reservoirs) showed stable water levels but high nutrient concentrations, which led to eutrophic conditions and communities dominated by a few tolerant species. Group D, which included small agricultural reservoirs and floodplain wetlands, had complex shorelines (highest RI) and supported the higher diversity of aquatic plants. This indicates that habitat heterogeneity can mitigate moderate physical disturbances and enhance richness. Canonical Correspondence Analysis and Variation Partitioning Analysis revealed that community structure is primarily influenced by hydrological disturbance, chemical stress (eutrophication), salinity, and shoreline complexity. These analyses confirmed that the interplay of these environmental factors explains community variation more effectively than any single factor alone. Our findings demonstrate that lake plant communities are shaped by a complex interaction of geomorphological, hydrological, and chemical factors. Therefore, effective lake management must adopt an integrated approach, considering both water-level regulation and shoreline complexity to enhance ecological integrity.

본 연구는 고구마(Ipomoea batatas L.) 재배에서 토양 수분 함량별 고구마 괴근의 형태 및 수량 변화를 분석하기 위해 2023년부터 2024년까지 2년간 경상국립대학교 내동캠퍼스 부속농장에서 수행되었다. 시험 1년차(2023년) 처리구는 건조구(DD, dry)와 과습구(WW, wet), 대조구로 적습구 (N, normal)를 설정하였으며, 시험 2년차(2024년)는 건조구(DD), 반건조구(D, semi-dry), 과습구(WW), 반과습구(W, semi-wet), 대조구로는 적습구(N, Normal)를 설정하였다. 2년간 고구마 전 생육기간 평균 토양 수분함량은 반건조구 23.2%, 건조구 19.9%, 적습구 32.5%, 반과습구 43.3%, 과습구 47.6%로 나타났다. 2년간의 시험 결과, 괴근 길이는 적습구에서 각각 20.9, 21.3 cm로 가장 길었고, 괴근 직경 또한 적습구에서 각각 8.10 cm, 7.50 cm로 가장 길었다. 적습구의 장폭비는 2.58, 3.00으로 방추형으로 나타났고, 괴근 모양은 달걀형이 각각 주당 3.87, 5.06 개로 가장 높았고, 건조구와 과습구는 부정형 괴근의 발생 비율이 적습구 보다 증가하였다. 괴근 수량은 2년간 적습구에서 각각 3.15, 4.86 ton 10a-1로 가장 높았다. 반면, 적습구 대비 건조구에서는 평균 54.4%, 과습구는 평균 47.3% 감소하는 경향을 나타냈다. 본 연구를 통해 토양 수분 함량에 따라 다양한 형태의 괴근이 생산될 수 있으며, 용도에 맞춰 형태 조절이 가능함을 확인하였다. 특히, 토양 수분을 약 30% 내·외로 유지할 경우 괴근 형성과 비대가 촉진되며, 수량 증대와 함께 선호도가 높은 달걀형 고구마 생산이 가능할 것으로 사료된다.

In this paper, poly(glycolic acid–co-DL–lactic acid) (PGDLLA)/poly(ɛ-caprolactone) (PCL) incompatible nanocomposites were combined with multiscale modeling (MSM) in a ratio of 80/20. Since the behavior and mechanical properties of blends depend significantly on the interphase region, the compatibilizer poly(l,l-lactic acid–co-ɛ-caprolactone) (P(lLA-co-ɛ-CL)) was used to improve compatibility and graphene oxide (GO) was used to increase the interphase strength of PGDLLA matrix/PCL. This work was done by mixing solvent to achieve the optimum disperse of GO in the matrix. The investigation of interfacial phenomenon by the theoretical interfacial models is important. Under the assumption of constant modulus and elastic deformation in the zero interface region, the predictions in this region are more unreliable when the calculations of experimental mechanical properties are analyzed in detail. In this study, PGDLLA/P(lLA-co-ɛ-CL)/PCL compounds were compared with the MSM approach to predict the plastic deformation in the stress–strain behavior. In contrast to the hypothesis that a simple look at the interphase area in nanocomposites, a finite element code is proposed to evaluate the efficiency of the interphase area. Both experimental results and FEM analysis showed that Young’s modulus increases by incorporating GO into GO/PGDLLA/P(lLA-co-ɛ-CL)/PCL nanocomposites; the amount of increase for incorporating 1 phr GO is about 61%.