https://scholarworks.bwise.kr/erica/handle/2021.sw.erica/101 2026-03-19T00:26:30Z https://scholarworks.bwise.kr/erica/handle/2021.sw.erica/126180 Title: Simultaneous application of rice straw and sulfate in paddy soil under flood-drain conditions and its consequence on arsenic mobility Authors: An, Jinsung; Yoon, Sang-Gyu; Kwak, Ihn-Sil; Song, Ki-Han Abstract: This study investigated the impact of the simultaneous application of rice straw (RS) and sulfate, mimicking actual agricultural practices, on arsenic (As) mobility in paddy soils under repetitive redox oscillation conditions. While previous studies primarily focused on the individual effects of organic amendments or sulfate on As mobility, this study explored their combined effects to provide a more comprehensive understanding of As dynamics in paddy soils. Microcosm experiments were conducted to observe changes in As mobility during two flood-drain cycles, analyze As and iron (Fe) fractionation using Wenzel sequential extraction, and examine changes in the relative abundance of microorganisms involved in Fe reduction. The simultaneous application of RS and sulfate increased the relative abundance of microorganisms involved in Fe reduction and promoted reducing conditions, significantly increasing Fe oxide reductive dissolution and As concentrations in porewater during the first flood-drain cycle. Arsenic concentrations in porewater ranged from 0.4 to 5.3 mg/L without applications and from 4.3 to 20.7 mg/L with simultaneous application of RS and sulfate. Meanwhile, Redox oscillations decreased As mobility by approximately 68-87 %, attributed to decreased dissolved organic carbon concentrations and increased Fe oxide crystallinity. These findings highlight the dynamic nature of As mobility in response to environmental factors associated with actual agricultural practices and providing valuable insights into understanding As contamination in paddy soils. 2026-04-01T00:00:00Z https://scholarworks.bwise.kr/erica/handle/2021.sw.erica/127371 Title: Ternary thermoresistive strain dependent nanocomposite for transverse mode analysis of conductors Authors: Haghgoo, Mojtaba; Ansari, Raza; Hassanzadeh-Aghdam, Mohammad Kazem; Jamali, J.; Sahmani, Saeid; Jang, Sunghwan Abstract: A ternary carbon nanotube (CNT) carbon black (CB) nanocomposite is analyzed studying the synergistic effect between CNT and CB on electrical conductivity. The assessment of the thermoresistivity and piezoresistivity of the nanocomposite with dispersed nanofillers of different diameters and conductivity ranges is investigated. By considering CBs with CNTs in the developed network model, Monte Carlo simulation results correlate well with experimental data. The effects of barrier height, aspect ratio and transverse mode are investigated. To guarantee the convergence of piezoresistivity, the number of CNTs was selected larger than a threshold amount, and this enforced a modified calculation scheme using parallel rows of series resistors formed through conductors. Results indicate that the electrical resistance decreased with increased temperature with higher temperature coefficient of resistance producing more prominent drops in comparison with the polymer thermal expansion minor effect. On this basis, the center mechanism about improving the electrical properties of the composite were high intrinsic conductivity and large aspect ratio CNTs selected with small concentrations of CB nanoparticles. The results demonstrate that increasing the number of transverse modes enhances thermoresistivity by modifying tunneling resistance. © 2025 Elsevier Ltd. 2026-03-01T00:00:00Z https://scholarworks.bwise.kr/erica/handle/2021.sw.erica/127090 Title: Efficient PCMs selection to improve the productivity of modified solar distillers using a corrugated absorber, nanoparticle-enhanced PCMs, and a copper heating coil integrated with a cylindrical parabolic concentrator Authors: Abdulrahman Alsaleh, Naser Abdulrahman; Joseph, Abanob; Abdelgaied, Mohamed; Ataya, Sabbah; Jang, Sunghwan; Sharshir, Swellam Wafa Abstract: Freshwater scarcity is one of the most critical global challenges, and solar distillation provides a sustainable alternative to conventional desalination technologies. However, its widespread use is limited by low productivity and dependence on variable solar radiation. This study presents a comparative experimental evaluation of three phase change materials (PCMs)—Soy wax, Paraffin wax, and Vaseline—combined with an innovative set of optimization techniques for solar distillers. The design integrates a corrugated tray-shaped absorber to enlarge the evaporation area, a silver-nanoparticle-enhanced PCM reservoir to improve heat storage and thermal conductivity, and a parabolic cylindrical concentrator (CPC) with a copper coil loop to supply concentrated external heat. Experiments were conducted in three stages, each testing one PCM configuration against a conventional solar distiller (CSD). The findings show that Soy wax delivered the best overall performance, achieving a cumulative yield of 16.68 L·m−2·day−1, corresponding to a 274.83 % increase over the CSD (4.45 L·m−2·day−1). Productivity improvements reached 248.31 % with Paraffin wax and 232.58 % with Vaseline. Energy and exergy efficiencies improved to 47.52 %/174.58 % for Soy wax, 35.92 %/134.58 % for Paraffin wax, and 29.58 %/112.50 % for Vaseline. Economically, the Soy wax design reduced the cost of potable water by 50.20 %, achieving 0.0038 $/L. Environmentally, it also achieved the highest impact with a 268.29 % improvement in CO₂ mitigation and carbon-credit generation compared to the CSD. Future work should explore larger-scale deployment, GIS-based site selection, and machine learning optimization for predictive performance and smart operation. © 2025 Elsevier B.V., All rights reserved. 2026-02-01T00:00:00Z https://scholarworks.bwise.kr/erica/handle/2021.sw.erica/127334 Title: Photo-weathering effects on pyrolysis-GC/MS quantification of microplastics: Surface oxidation correlations and correction strategies Authors: Lee, Ye-eun; Park, Saerom; An, Jinsung; Kim, I. Tae Abstract: Microplastics (MPs) in the environment are typically weathered rather than pristine, and their altered physicochemical properties challenge accurate quantification. Pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) is widely used for MP analysis, but its reliability depends on the stability of specific pyrolyzates, which may be affected by photo-weathering. This study examined the effects of photo-weathering on Py-GC/MS signals of fragment-type MP from polyethylene (PE), polypropylene (PP), and polyethylene terephthalate (PET). MPs were irradiated for 600 h using Xenon and UVC lamps. Surface oxidation was assessed by Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy, while wettability and particle morphology were evaluated via water contact angle (WCA) and particle size distribution analyses. Two diagnostic pyrolyzates per polymer were selected and their peak intensities were quantitatively evaluated against surface oxidation indices. Both irradiation sources significantly influenced Py-GC/MS quantification for all polymers. For PE under Xenon irradiation and PP under UVC irradiation, 1-decene and 2,4-dimethyl-1-heptene exhibited consistent linear declines (r2 = 0.71–0.82) with exposure time that correlated with oxidation metrics. WCA proved to be the most reliable predictor for PE, while O/C ratio best captured PP degradation. Conversely, long-chain pyrolyzates (1,20-heneicosadiene, 2,4,6,8-tetramethyl-1-undecene) responded irregularly under oxidative stress, limiting their use as indicators. For PET, benzophenone depletion under UVC indicated oxidation sensitivity, but secondary conversion from benzoic acid in the presence of CaCO<inf>3</inf> caused signal variability. Despite suppressed signals, predictable declines in selected pyrolyzates can serve as correction indicators when integrated with polymer-specific oxidation metrics. This framework provides the first robust guideline for improving Py-GC/MS quantification of weathered MPs. © 2025 Elsevier Ltd 2026-02-01T00:00:00Z