https://scholar.dgist.ac.kr/handle/20.500.11750/1921 2026-06-03T20:17:41Z https://scholar.dgist.ac.kr/handle/20.500.11750/60361 Title: Transformation of rusted iron into an IDE-based sensor for ethanol detection and self-powered humidity sensing Author(s): Belal, Mohamed Ahmed; Hajra, Sugato; Bayoumy, Ahmed M.; Eldesouki, Mohammed H.; Kaja, Kushal Ruthvik; Panda, Swati; Ramu, Dandugudumula; Abd El-moneim, Ahmed; Achary, P. G. R.; Kim, Hoe Joon Abstract: Volatile organic compound (VOC) sensors and triboelectric nanogenerators (TENGs) are highly significant applications with broad potential across multiple fields, including non-invasive disease biomarker monitoring and sustainable energy harvesting for electronic devices. This study reports the synthesis of alpha-Fe2O3 nanoparticles derived from recycled iron screws using a closed-system nitric acid leaching process, followed by calcination, offering low-cost, eco-friendly, and added-value products that reduce the negative environmental impacts of waste materials. The synthesized material is thoroughly characterized to investigate its phase purity, surface morphology, and suitability for TENG and ethanolsensing applications. A spray coating technique was employed to deposit the alpha-Fe2O3 ink onto laserinduced graphene interdigitated electrodes (LIG-IDE) fabricated via CO2 laser engraving of a polyimide flexible substrate. The fabricated alpha-Fe2O3-based sensor exhibits multifunctional capabilities, owing to the material's biocompatibility. The alpha-Fe2O3-based sensor exhibits a high performance for ethanol detection at room temperature, with a sensor response of 47 and response/recovery times of 104/126 s, respectively, at 100 ppm. The TENG device exhibits stable output characteristics of 3 V and a maximum power of 9.5 nW. The electrical output from biomechanical motions confirms its potential for energy harvesting applications, and a further self-powered humidity sensor was demonstrated. These results highlight the excellent potential of alpha-Fe2O3 for both TENG applications and VOCs detection, recommending its use in environmental and industrial monitoring. 2026-06-30T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/60242 Title: 물질 계측 센서, 물질 계측 시스템 및 물질 계측 방법 Author(s): 장일류; 김회준 https://scholar.dgist.ac.kr/handle/20.500.11750/60232 Title: PDMS/BNT-BKT Composite-Based Triboelectric Nanogenerator for Self-Powered Health Monitoring Author(s): Sahu, Manisha; Hajra Sugato; Padhan, Aneeta Manjari; Park, Kyeong Jun; Hull, Anna Rose; Pakawanit, Phakkhananan; Keum, Hohyun; Kim, Hoe Joon Abstract: The field of sensors is moving toward miniaturization, and it requires suitable power sources for operation. In this context, the triboelectric nanogenerator (TENG) can become a partial solution as a sustainable power source for various sensors. The present work focuses on developing a TENG fabricated from the flexible polymer-ceramic composite films, i.e., PDMS-Bi0.5(Na1-x K x )0.5TiO3 where x = 0.1, 0.14, 0.18, and 0.22 (BNT-BKT), which act as potential self-powering devices for sleep and respiration monitoring. The structural and spectroscopic characterization of the BNT-BKT particles showcased the presence of a morphotropic phase boundary. The dielectric constant increases with the inclusion of BKT, and the observed dielectric loss of the BNT-BKT samples is much less compared to that of the parent BNT samples. An attempt is made to fabricate a TENG based on PDMS/BNT-BKT composites (CFs). The triboelectric nanogenerator with 10 wt % PDMS/BNT-BKT CF gives an electrical output voltage of 292 V and a current of 3.47 mu A. Finally, a calculator is successfully powered by charging a 47 mu F capacitor using the fabricated TENG device. Furthermore, the TENG device is utilized for continuous monitoring of breathing patterns during rapid exercise and also jerks during sleep, underscoring its wide application in healthcare monitoring. 2025-12-31T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/60227 Title: Toward virtual bladder: real-time bladder volume monitoring with flexible AuCNT strain sensors Author(s): Cho, Youngjun; Jo, Yujin; Kang, Minseok; Shin, Heejae; Cho Jeongmok; Jeong Hyunghwa; Suh Hyunsuk Peter; Pak Changsik John; Park, Jeonhyeong; Kwon Soonchul; Choi Hongsoo; Yu, Jaesok; Kim, Hoe Joon; Lee, Sanghoon Abstract: Digital twin technology holds considerable potential for personalized diagnostics and treatment of bladder dysfunction, particularly neurogenic conditions such as underactive bladder (UAB). In this study, to address the need for precise monitoring, we introduce a flexible, stretchable strain sensor composed of gold-coated carbon nanotubes (AuCNTs) embedded in Ecoflex. We specifically designed a three-channel configuration to capture anisotropic expansion and evaluated the sensor's performance using both two-dimensional balloon models and ex-vivo three-dimensional porcine bladder models. As a result, the AuCNT sensor demonstrated high sensitivity, and the three-channel design significantly enhanced spatial accuracy compared to single-channel approaches. Based on these measurements, we created a preliminary "Virtual Bladder" model that provides dynamic, real-time visualization of bladder volume changes. While our current model requires further development to incorporate multimodal data and anatomical variability, it serves as a foundational step towards developing advanced digital twin frameworks and closed-loop neuromodulation systems for bladder dysfunction. 2025-12-31T15:00:00Z