https://scholar.korea.ac.kr/handle/2021.sw.korea/361 Sun, 05 Apr 2026 17:22:57 GMT 2026-04-05T17:22:57Z https://scholar.korea.ac.kr/handle/2021.sw.korea/268525 Title: Exploration of deep learning leak detection model across multiple smart water distribution systems: Detectable leak sizes with AMI meters Authors: Jun, Sanghoon; Jung, Donghwi Abstract: Numerous deep learning (DL) models have been developed for leak detection in water distribution systems (WDSs). However, significant lack of knowledge still remains concerning their detectability and the smallest detectable leak sizes across various WDSs. To address these research gaps, this study explores the performance of a DL leak detection model across eleven smart WDSs. A convolutional neural network (CNN) is employed to identify leaks using the spatially distributed pressure response images derived from the difference between advanced metering infrastructure (AMI) measurements and predictions from a well-calibrated hydraulic model (i.e., digital twin). Ten leak magnitudes are evaluated for each WDS, and three performance metrics (recall, precision, and F1 score) are calculated to assess the detectability and the detectable leak sizes of the CNN. The analysis reveals that the DL model's detection ability is highly impacted by WDS type, whether transmission- or distribution-oriented. The former networks exhibit low accuracy in identifying leaks due to the indistinguishability of pressure response images between normal and leak conditions. On the other hand, the latter networks generally achieve higher precision and recall results and can detect smaller leaks. Moreover, the smallest detectable leak sizes are more sensitive to WDS structural parameters (pipe diameter and length) than system hydraulics (system demand). Examining pipe characteristics along the leakage flow path provides most useful information in determining the detectability of leaks. Mon, 01 Dec 2025 00:00:00 GMT https://scholar.korea.ac.kr/handle/2021.sw.korea/268525 2025-12-01T00:00:00Z https://scholar.korea.ac.kr/handle/2021.sw.korea/267336 Title: Aligned Ion Conduction Pathway of Polyrotaxane-Based Electrolyte with Dispersed Hydrophobic Chains for Solid-State Lithium-Oxygen Batteries Authors: Kim, Bitgaram; Sung, Myeong-Chang; Lee, Gwang-Hee; Hwang, Byoungjoon; Seo, Sojung; Seo, Ji-Hun; Kim, Dong-Wan Abstract: Strategic materials design of polyrotaxane-based electrolytes was suggested by aligning the ion conduction pathways and dispersing hydrophobic chains for solid-state Li-O2 batteries.Owing to intentional design, solid-state Li-O2 battery resulted in stable potential over 300 cycles at 25 degrees C. A critical challenge hindering the practical application of lithium-oxygen batteries (LOBs) is the inevitable problems associated with liquid electrolytes, such as evaporation and safety problems. Our study addresses these problems by proposing a modified polyrotaxane (mPR)-based solid polymer electrolyte (SPE) design that simultaneously mitigates solvent-related problems and improves conductivity. mPR-SPE exhibits high ion conductivity (2.8 x 10-3 S cm-1 at 25 degrees C) through aligned ion conduction pathways and provides electrode protection ability through hydrophobic chain dispersion. Integrating this mPR-SPE into solid-state LOBs resulted in stable potentials over 300 cycles. In situ Raman spectroscopy reveals the presence of an LiO2 intermediate alongside Li2O2 during oxygen reactions. Ex situ X-ray diffraction confirm the ability of the SPE to hinder the permeation of oxygen and moisture, as demonstrated by the air permeability tests. The present study suggests that maintaining a low residual solvent while achieving high ionic conductivity is crucial for restricting the sub-reactions of solid-state LOBs. Mon, 01 Dec 2025 00:00:00 GMT https://scholar.korea.ac.kr/handle/2021.sw.korea/267336 2025-12-01T00:00:00Z https://scholar.korea.ac.kr/handle/2021.sw.korea/271440 Title: Enhanced performance of TFC nanofiltration membranes based on UiO-66-NH2 mixed matrix membranes Authors: Hu, Peng; Yang, Liu; Zhao, Fangbo; Park, Hee-Deung; Chen, Hongxu; Li, Zhiguo; Geng, Chengbao Abstract: This study proposes an innovative strategy by incorporating UiO-66-NH2 into a polyethersulfone (PES) substrate and fabricating thin-film composite (TFC) membranes via the interfacial polymerization (IP) method. Incorporation of UiO-66-NH2 to the substrate membrane changes the structure of the polyamide (PA) layer of the TFC membrane. The TFC membranes have a better hydrophilicity, rougher surface, and thicker PA layer. The TFC M-3 membrane demonstrates exceptional performance: the pure water flux (PWF) of 10.58 L·m−2·h−1·bar−1, the rejection (R) of 98.2 % for Na2SO4 and 95.5 % for MgSO4. Furthermore, the long-term stability of the membrane is improved substantially. It still maintains a high PWF of 10.17 L·m−2·h−1·bar−1 and a high R of over 96 % for Na2SO4. This study demonstrated that the incorporation of UiO-66-NH2 to the substrate membrane can significantly improve the nanofiltration performance of the TFC membrane. © 2025 Elsevier B.V. Wed, 01 Oct 2025 00:00:00 GMT https://scholar.korea.ac.kr/handle/2021.sw.korea/271440 2025-10-01T00:00:00Z https://scholar.korea.ac.kr/handle/2021.sw.korea/270784 Title: Post-heating flexural behavior of CFRP bar in ultra-high-performance fiber-reinforced concrete (UHPFRC) members after thermal exposure Authors: Yoo, Sun-Jae; Parr, Jean-Luc Malan; Zhang, Mingzhong; Yang, Jun-Mo; Yoon, Young-Soo Abstract: The post-heating flexural performance of carbon fiber-reinforced polymer (CFRP) bars after thermal exposure plays a critical role in determining whether concrete members should be demolished or strengthened. This study investigates post-heating flexural performance of a CFRP bar in ultra-high-performance fiber-reinforced concrete (UHPFRC) after thermal exposure. A total of six UHPFRC members were prepared, and were exposed up to 200, 400, and 600 °C with unheated members serving as a control group, and the results were also compared to that of UHPFRC reinforced with steel bars. After thermal exposure at 200 °C, the ultimate load of the CFRP bar reinforced UHPFRC increased by approximately 16.7 % compared to the unheated member, but it dropped by 41.4 and 83.5 % after thermal exposure at 400 and 600 °C. For steel bar reinforced UHPFRC members, ultimate load decreased by approximately 33.4 %, with bar rupture observed after exposure at 600 °C. Thermal cracks appeared along the longitudinal direction after exposure at 400 °C, but no thermal cracks were observed after exposure at 600 °C. For CFRP bar reinforced UHPFRC members, the initiation of slip was accelerated with increasing temperatures, whereas almost zero slip was observed for steel bars at ambient and after thermal exposure at 600 °C. For sectional analysis, the materials were modeled to account for the modified tensile strength of CFRP bars after exposure at 400 and 600 °C. The flexural strength predicted by the sectional analyses showed good agreement with the experimental results, with an average ratio of 0.98 between experimental and predicted results. © 2025 Elsevier Ltd Mon, 01 Sep 2025 00:00:00 GMT https://scholar.korea.ac.kr/handle/2021.sw.korea/270784 2025-09-01T00:00:00Z