Article
Chemistry, Analytical
Rodica-Cristina Voicu, Catalin Tibeica
Summary: This paper investigates an aluminum micro-tweezer for micromanipulation applications, including design, simulation, fabrication, characterizations, and experimental measurements. Electro-thermo-mechanical FEM-based simulations using COMSOL Multiphysics were conducted to describe the behavior of the micro-electro-mechanical system (MEMS) device. The micro-tweezers were fabricated in aluminum, as structural material, by surface micromachining processes. Experimental measurements were performed and compared with the simulation results. A micromanipulation experiment using titanium microbeads from 10-30 μm was conducted to confirm the performance of the micro-tweezer. This study further explores the use of aluminum as a structural material for MEMS devices intended for pick-and-place operations.
Article
Instruments & Instrumentation
Sam Hoh, Tim Helps, Richard Suphapol Diteesawat, Majid Taghavi, Jonathan Rossiter
Summary: Electro-ribbon actuators are high-performance electric artificial muscles that offer high flexibility and low power consumption, enabling the deployment of compact folding structures. The electro-lattice actuator (ELA) is a compliant, three-dimensional lattice structure that contracts upon the application of a potential difference, providing a new approach for 3D actuating structures.
SMART MATERIALS AND STRUCTURES
(2021)
Article
Engineering, Electrical & Electronic
Zhaoguo Jiang, Yuan Li, Qinglin Wang
Summary: Dielectric Electro-Active Polymer (DEAP) has been widely used in intelligent bio-inspired robotics. This paper proposes a feedforward compensation scheme to cancel the creep phenomena in DEAP-based actuators, considering different control voltages and external mechanical loads. Comparative experiments show that the proposed compensator significantly reduces the creep induced by varied inputs.
IEEE SENSORS JOURNAL
(2022)
Article
Nanoscience & Nanotechnology
Wei Wang, Yang Zhang, Yong-Lai Zhang, Jia-Rui Zhang, Xiang-Chao Sun, Dong-Dong Han, Hong-Bo Sun
Summary: This paper presents stimuli-responsive actuators (SRAs) that can convert environmental energies to mechanical works. These paper actuators are fabricated through a simple painting process on common papers and can exhibit complex deformations. They are responsive to multiple stimuli and can be programmed to achieve more complex deformations by controlling the drawing orientation.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Nanoscience & Nanotechnology
Wei Wang, Yang Zhang, Yong-Lai Zhang, Jia-Rui Zhang, Xiang-Chao Sun, Dong-Dong Han, Hong-Bo Sun
Summary: This paper introduces a multi-responsive paper actuator that can undergo complex deformation through a simple painting process on common papers. The paper actuator allows for large-scale and low-cost production, and it can respond to multiple stimuli such as moisture, temperature, light, and volatile organic compounds. The bending deformation of the paper actuator can also be controlled by pencil drawing orientation, enabling more complex deformations. Several applications of these multi-responsive paper actuators, including smart devices, crawling actuators, and attitude-control actuators, have been demonstrated. The development of these cost-effective actuators holds great promise for various practical applications.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Multidisciplinary Sciences
Shufen Chu, Pan Liu, Yin Zhang, Xiaodong Wang, Shuangxi Song, Ting Zhu, Ze Zhang, Xiaodong Han, Baode Sun, Mingwei Chen
Summary: In this study, the authors report real-time atomic-scale observations of grain boundary dislocation climb in nanostructured gold at room temperature. The climb of a dislocation is found to occur through stress-induced reconstruction of neighboring atomic columns. The proposed atomic route of dislocation climb is energetically favorable, as demonstrated by Monte Carlo simulations. The in situ observations also reveal the significance of grain boundary dislocation climb in controlling the microstructures and properties of nanostructured metals.
NATURE COMMUNICATIONS
(2022)
Article
Chemistry, Multidisciplinary
Rassoul Tabassian, Manmatha Mahato, Sanghee Nam, Van Hiep Nguyen, Araz Rajabi-Abhari, Il-Kwon Oh
Summary: The study introduces an electro-active and photo-active soft actuator based on vanadium oxide nanowires, which shows greatly enhanced actuation deformation and speed when controlled by both light and electric sources. The nanowires with high surface area and hydrophilicity improve the actuator's performance significantly.
Article
Mathematics, Applied
Qigang Yuan, Zhibo Cheng, Xueping Li
Summary: This study investigates a canonical mass-spring model of electrostatically actuated Micro-Electro-Mechanical System (MEMS). The existence and bifurcations of periodic solutions are explored using the continuation theorem of Manasevich and Mawhin with techniques of a priori estimate and bifurcation theory. The main results provide answers to an open problem proposed by P. Torres and reveal saddle node and period doubling bifurcations in the system, resulting in the multiplicity of periodic solutions. Additionally, the study discovers bistability of periodic solutions, generated by the combination of these bifurcations, shedding light on the pull-in instability in the system. Finally, periodic orbits with different stability and corresponding time series are presented to illustrate the findings.
COMMUNICATIONS IN NONLINEAR SCIENCE AND NUMERICAL SIMULATION
(2023)
Article
Construction & Building Technology
Paulo Vtor Camin Pena, Rondinele Alberto dos Reis Ferreira, Antonio Carlos dos Santos, Andrielli Morais de Oliveira
Summary: The aim of this study was to evaluate the behavior of steel fiber reinforced concrete (SFRC) compared to concrete without fiber at the strength classes of 30 MPa and 50 MPa under compression creep. Various volumetric contents of steel fibers were tested, and the elastic deformation (ED) and specific creep (SC) values were measured. The results showed that the addition of steel fibers reduced creep strain and had a positive impact on the durability properties of the concrete.
JOURNAL OF BUILDING ENGINEERING
(2023)
Article
Construction & Building Technology
Yidong Gan, Claudia Romero Rodriguez, Erik Schlangen, Klaas van Breugel, Branko Savija
Summary: The experimental investigation of cement paste at the microscale revealed that the mechanical properties are rate-dependent. It was observed that with increasing strain rate, the flexural strength and elastic modulus of the material increase while the strain at peak stress decreases. Possible mechanisms such as creep and Stefan effect were discussed as contributing factors to the rate-dependent behaviour.
CEMENT & CONCRETE COMPOSITES
(2021)
Article
Chemistry, Analytical
Bo Wang, Hironobu Tahara, Takamasa Sagara
Summary: This study aimed to enhance the redox-driven deformation efficiency of a viologen pendant poly-L-Lysine based glutaraldehyde cross-linked hydrogel, and found that the addition of conductive fillers or anionic polymers could affect its contraction and expansion rates. Choosing the appropriate filler and polymer can optimize the performance of the hydrogel actuators.
SENSORS AND ACTUATORS B-CHEMICAL
(2021)
Article
Computer Science, Interdisciplinary Applications
Yan Gao, Qing Chen, Quan Yuan, Yu-Hsing Wang
Summary: Biaxial shear and creep numerical simulations based on discrete element method were conducted on dense and loose sands to investigate the kinematics and micro mechanism of creep. The simulations qualitatively replicated the macroscopic behavior of sand during shearing and creep, and the evolution of internal structure was described using contact forces, contact normals, and voids. The contributions of different modes of contact motion to sample deformation were explored, and it was found that the change of creep stage can be characterized by the anisotropy evolution of internal structure, and different modes of contact motion have complex effects on macro sand deformation during creep and shearing process.
COMPUTERS AND GEOTECHNICS
(2023)
Article
Materials Science, Composites
Amir Hossein Ebrahimi, Hojjat Zamyad, Javad Safaei, Samaneh Sahebian
Summary: In this study, a fast-response soft composite actuator was developed by mixing silicone elastomer and ethanol. The actuator utilizes electrical actuation to heat ethanol, causing a liquid-vapor transition and generating the required pressure for movement. Design variables such as temperature response, chemical composition, mechanical properties, force generation, and microstructure were optimized. The actuator showed a high load-to-weight ratio and stability under multiple working cycles, making it suitable for various robotic applications.
JOURNAL OF THERMOPLASTIC COMPOSITE MATERIALS
(2023)
Article
Chemistry, Analytical
Jun -Ho Kim, Jaehwan Kim
Summary: With the increasing desire for biomimicry, electroactive artificial muscles are being utilized in various bioinspired applications. This study reports on the use of 3D dendritic nickel cobalt sulfide nanorods on graphene electrodes to achieve high-performance artificial muscles with stable electrochemical reactivity. The resulting muscles show significant enhancements in bending performance and stable response to input signals, enabling the development of bioinspired soft locomotive robots and expanding the soft electronics industry.
SENSORS AND ACTUATORS B-CHEMICAL
(2023)
Article
Materials Science, Multidisciplinary
Nimitt G. Patel, Philip A. Yuya
Summary: This study focuses on the characterization of nanoscale viscoelastic properties of gold nanoparticle-reinforced chitosan nanocomposites using nanoindentation. The results show that the modulus and plasticity index of the nanocomposites increase with an increase in the concentration of gold nanoparticles. Moreover, the time-dependent viscous response of the nanocomposites is mainly governed by the response of the matrix.
MATERIALS TODAY COMMUNICATIONS
(2022)
Article
Chemistry, Physical
K. Karuppasamy, Ranjith Bose, Dhanasekaran Vikraman, Sivalingam Ramesh, Heung Soo Kim, Emad Alhseinat, Akram Alfantazi, Hyun-Seok Kim
Summary: In this study, cost-effective and highly active Co3O4@C nanostructures were designed and developed from two different metal-organic framework ligands. The unique morphologies and excellent surface area of the catalysts resulted in increased active centers for oxygen evolution activity. Among them, Co3O4@C-TMA exhibited favorable Tafel kinetics and small overpotential for oxygen evolution. This study not only designs effective electrodes for oxygen evolution activity, but also proposes various multi-functional catalysts for renewable energy conversion applications.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Engineering, Electrical & Electronic
Jihyun Kim, Joo-Hyung Kim
Summary: This article introduces a continuous operating pre-concentrator for trace gas analysis, which can achieve a significant increase in trace gas concentrations using relatively simple mass diffusion separation stages, without interrupting the gas flows. The pre-concentrator is useful in detecting the real-time variations in trace gas concentration and requires less operational time.
SENSORS AND ACTUATORS A-PHYSICAL
(2023)
Article
Polymer Science
Muhammad Latif, Yangxiaozhe Jiang, Jongmin Song, Jaehwan Kim
Summary: Additive manufacturing technology has revolutionized the manufacturing process of polymer composites by enabling the construction of complex products with unique materials, functions, and structures. However, the printing of high-concentration nanocellulose structures using this technology often faces challenges related to adhesion and shape fidelity. This research presents an economical approach to fabricate structures by printing high-concentration nanocellulose layer-wise patterns. The study demonstrates the successful fabrication of two different composites and highlights the importance of optimal blend compositions and resin infusion methods in achieving high mechanical strength and interface adhesion.
Article
Chemistry, Multidisciplinary
Sivalingam Ramesh, C. Karthikeyan, A. S. Hajahameed, N. Afsar, Arumugam Sivasamy, Young-Jun Lee, Joo-Hyung Kim, Heung Soo Kim
Summary: Zinc oxide nanoparticles were synthesized using a simple chemical route and characterized by XRD, SEM, and EDS analysis. The addition of 4-dimethylaminobenzaldehyde (4DB) increased the band gap energy of the nanoparticles. HOMO-LUMO analysis was conducted on the synthesized clusters, providing information about their ionization energy, electron affinity, and other thermodynamic properties. The antimicrobial properties of the nanoparticles were studied against different bacteria.
Article
Materials Science, Multidisciplinary
Miae Kang, Jin Hyun Park, Ayeong Kim, Seongwoo Lee, Chang Young Lee, Joo-Hyung Kim, Changsik Song, Han Yong Bae, Jihyun Kim
Summary: Early detection of chemical warfare agents is crucial. This study introduces a fast response-recovery chemicapacitor for a nerve agent simulant with high selectivity and sensitivity. The chemicapacitor outperforms chemiresistive sensors in terms of response-recovery dynamics and exhibits superior sensitivity. It also demonstrates excellent selectivity for the nerve agent simulant and shows potential in reducing casualties by early identification of chemical threats.
ECS JOURNAL OF SOLID STATE SCIENCE AND TECHNOLOGY
(2023)
Article
Mathematics
Izaz Raouf, Prashant Kumar, Hyewon Lee, Heung Soo Kim
Summary: With increasing customer demand, industry 4.0 and smart factories have gained significant attention. In these factories, timely fault detection and diagnosis for robotic components are crucial. Previously, traditional fault detection algorithms were used, but they lacked generalization. To address this issue, transfer learning using the VGG16 model was proposed, and experiments were conducted under various working conditions. The proposed approach showed effective fault detection performance and generalization capabilities.
Review
Mathematics
Salman Khalid, Jinwoo Song, Izaz Raouf, Heung Soo Kim
Summary: Thermal power plants (TPPs) are crucial for energy supply, and their safe and efficient operation is a top priority. Advanced fault detection and diagnosis (FDD) techniques have been adopted to minimize maintenance shutdowns and costs. This paper provides a systematic review of advanced FDD methods for TPPs, comparing and analyzing these techniques comprehensively. It discusses relevant FDD strategies, their applications, and emphasizes their significance in sustainable energy development. The review explores recent advancements in intelligent FDD techniques for boilers and turbines in TPPs, and highlights the need for further research and development in this field.
Article
Biology
Muhammad Sohail, Jun Young Kim, Jaehyun Park, Heung Soo Kim, Jaehun Lee
Summary: The use of condyles-based method provides a reliable and efficient way to determine the anatomical points necessary for accurate measurement and implant placement in total knee arthroplasty. This method eliminates the need to register the lateral epicondyle or medial sulcus, improving the accuracy and efficiency of the registration process.
COMPUTERS IN BIOLOGY AND MEDICINE
(2023)
Review
Automation & Control Systems
Prashant Kumar, Izaz Raouf, Heung Soo Kim
Summary: This article provides a comprehensive study of fault prognosis and health management (PHM) strategies in smart factories, including both traditional and deep learning perspectives. The paper also discusses conventional health management methods and the latest trends in the PHM field in smart factories.
ENGINEERING APPLICATIONS OF ARTIFICIAL INTELLIGENCE
(2023)
Article
Energy & Fuels
Sivalingam Ramesh, K. Karuppasamy, H. M. Yadav, Young-Jun Lee, Arumugam Sivasamy, A. Kathalingam, Hyun-Seok Kim, Joo-Hyung Kim, Heung Soo Kim
Summary: This article thoroughly examines the electrochemical properties of ternary CuCo2S4 sulfides as electrode materials due to their low cost, high conductivity, and synergistic impact. By utilizing a hydrothermal reaction process aided by nanostructured CuCo2S4 secured on multiwalled carbon nanotubes/polypyrrole composite, the produced composite electrode displays increased specific capacitances and cyclic stability. The increased surface and morphological features of the CuCo2S4 on NMWCNT/PPy composite boost the electrochemical properties of the ternary composite electrode.
JOURNAL OF ENERGY STORAGE
(2023)
Article
Mathematics
Yeong Rim Noh, Salman Khalid, Heung Soo Kim, Seung-Kyum Choi
Summary: This paper proposes a novel framework for addressing the issue of imbalanced datasets in rotating machine fault diagnosis using a area-metric-based sampling method. The proposed method utilizes continuous wavelet transform and dilated convolutional neural network to improve diagnosis accuracy.
Review
Mathematics
Salman Khalid, Jinwoo Song, Muhammad Muzammil Azad, Muhammad Umar Elahi, Jaehun Lee, Soo-Ho Jo, Heung Soo Kim
Summary: This review paper highlights the critical role of structural prognostics and health management (SPHM) in aircraft maintenance. It compares traditional and modern approaches, evaluates their limitations, and showcases advancements in data-driven and model-based methodologies. The paper explores the effectiveness of machine learning and deep learning algorithms, as well as the potential of model-based approaches. Additionally, it examines the impact of digital twin technology in SPHM through real-life case studies.
Article
Engineering, Multidisciplinary
Siheon Jeong, Min-Gwan Kim, Joo-Hyung Kim, Ki-Yong Oh
Summary: This study proposes a thermal monitoring method using an infrared camera mounted on a UAV to inspect the health state of overhung transmission lines in outdoor environments. The method includes converting the thermal energy of the transmission lines into accurate temperature, eliminating thermal energy from other heat sources, and automatically tracking the lines for reliable thermal imaging. Field tests show that the proposed method overcomes current limitations and provides important insights for thermally monitoring overhung TLs in outdoor environments.
STRUCTURAL HEALTH MONITORING-AN INTERNATIONAL JOURNAL
(2023)
Article
Chemistry, Multidisciplinary
Mijin Won, Gyeongseok Oh, Hyunah Lee, Jaehwan Kim, Dong-Soo Kim
Summary: This paper presents a method for manufacturing humidity sensors on curved surfaces using 3D printing technology. The sensors are fabricated by printing electrodes on flat and 3D curved glass substrates, and coating cellulose nanofibers as a sensing layer. The sensors demonstrate high repeatability and sensitivity.
Article
Chemistry, Multidisciplinary
Sungjun Kim, Muhammad Muzammil Azad, Jinwoo Song, Heungsoo Kim
Summary: In this study, a solution to the data imbalance problem in laminated composite systems is proposed using a Wasserstein Generative Adversarial Network (WGAN) model with time-series data augmentation. The performance of the WGAN model is validated through fault diagnosis using a One-Dimensional Convolutional Neural Network (1D CNN). The results show that the proposed data augmentation significantly improves the fault diagnosis performance, with increased accuracy, precision, and sensitivity.
APPLIED SCIENCES-BASEL
(2023)
