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16th Electrical engineering Faculty Conference, BulEF 2024

作者： Gospodinova, Dilyana Panchev, Mihail Neznakomova, Margarita Dept. of Electrical Apparatus Faculty of Electrical Engineering Technical University of Sofia Sofia Bulgaria Dept. of Machine Elements and Nonmetallic Constructions Faculty of Mechanical Engineering Technical University of Sofia Sofia Bulgaria Dept. of Material Science and Technology of Materials Faculty of Industrial Technology Technical University of Sofia Sofia Bulgaria

ISBN: (纸本)9798350391671

The present paper introduces a novel technology aimed at improving the retention rate of nonwoven filter barriers produced using the wet method with short, waste wool fibers and dusts. These filter barriers are specifically designed to treat oil-contaminated wastewater. The study demonstrates that exposing the filter barriers to ultraviolet (UV) radiation with a wavelength of 254 nanometers on one or both sides increases their efficiency. The findings indicate that a treatment time of between 2 and 3 minutes with single-sided UV irradiation is sufficient for the wool-based filter barrier. Additionally, the research suggests that using a three-layer filter structure can enhance the filter barrier's efficiency to 1.26 g/g fibers (0.196 for a single-layer filter structure). The study recommends the implementation of an environmentally friendly and cost-effective process for producing efficient filter barriers from textile waste for water purification purposes. This process involves using UVC irradiation, which is simple to implement and has low associated costs. © 2024 IEEE.

关键词： Nonwoven fabrics

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Characterization study of perovskite solar cells with incorporation of organic long persistent luminescence

Characterization study of perovskite solar cells with incorp...

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2023 IEEE International Conference on Sensors and Nanotechnology, SENNANO 2023

作者： Sharma, Tejas Jun, H.K. Unviersiti Tunku Abdul Rahman Lee Kong Chian Faculty of Engineering and Science Dept. of Mechanical & Materials Engineering Kajang Malaysia Universiti Tunku Abdul Rahman Centre for Photonics and Advanced Materials Research Kajang Malaysia

ISBN: (纸本)9798350333312

Organic/inorganic metal halide perovskites are receiving a lot of interest as next generation solar technology material due to their low-cost and good performance. In this work, we investigated perovskite solar cells (PSCs) with the incorporation of long persistence luminescence (LPL) material. Room temperature mixed-cation perovskite material FAMAPbI3 was prepared for application in PSCs. To enhance the PSC performance, LPL material was integrated externally to the cell structure. XRD, SEM, and photoluminescence (PL) spectroscopy were performed to reveal the phase, morphology, and emission spectra of the samples. The findings revealed that LPL material affected the performance of PSCs to a certain degree. The charge-transfer features occurring at the interface between the electron transport layer and perovskite film were further examined using electrochemical impedance spectroscopy technique. From the optical observation, when electron donating group of TMB molecules were mixed with the electron accepting group of PPT molecules, it resulted a better luminescence effect. The PSC performances highlight the potential for removing expensive hole-transport layer and costly high-vacuum deposition techniques from the fabrication processes. © 2023 IEEE.

关键词： Perovskite solar cells

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Influence of Deformation of Compliant Rollers on Tape Steering During Automated Tape Placement 38

Influence of Deformation of Compliant Rollers on Tape Steeri...

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38th Technical Conference of the American Society for Composites, ASC 2023

作者： Fuessel, Lukas Cender, Thomas Gillespie, John W. Dept. of Mechanical Engineering University of Delaware NewarkDE19716 United States Center for Composite Materials University of Delaware NewarkDE19716 United States Dept. of Materials Science and Engineering University of Delaware NewarkDE19716 United States Dept. of Civil Engineering University of Delaware NewarkDE19716 United States

ISBN: (纸本)9781605956916

Automated tape placement with tape steering represents a process to manufacture lightweight composite structures. In our experimental studies, a Mikrosam Tape placement system with laser nip-point heating and a compliant consolidation roller has been used to quantify the limits of steering of continuous and highly aligned short fiber tapes (AS4/PEI with a fiber length of 3 mm). The minimum radius is typically limited by the compressive strain in the fiber direction that will buckle/wrinkle the inner radius of the tape. In the case of the aligned short fiber tapes, order of magnitude reduction in the minimum radius (50-100 mm) has been demonstrated by exploiting the in-plane extensibility of these tapes compared to inextensible continuous fiber (500-1000 mm). The tape deformation and path accuracy during steering experiments has been quantified using DIC methods. These results have indicated that the deformation of the compliant roller during compaction, placement and steering is a major factor. In this study, the deformation of the roller over the full range of consolidation forces (400-900 N) has been quantified to include load-deformation response, and pressure distribution within the contact area. In addition, DIC is used to measure the 3D deformation and strain fields within the roller across the width and circumference as well as to provide insight into the frictional interaction between the rubber surface and the substrate during static loading and constant velocity steering paths. A finite element model of the compliant roller is developed, and a parametric study is conducted investigating the effects of rubber durometer and friction within the rubber/substrate contact area. Relatively good correlation has been achieved using a rubber durometer of Shore hardness 45 in terms of load-deformation response. In the case of steering where the AFP head rotates, a torsional moment is imparted on the roller and the rubber is predicted to undergo shear deformation as w

关键词： Rubber

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mechanical Evaluation of Bone Scaffolds' Behavior under Compression 46

Mechanical Evaluation of Bone Scaffolds' Behavior under Comp...

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46th Annual International Conference of the IEEE engineering in Medicine and Biology Society, EMBC 2024

作者： Ntousi, Ourania A. Pleouras, Dimitrios S. Siogkas, Panagiotis K. Roumpi, Maria Kontaxis, Lykourgos C. Bourantas, George Deligianni, Despoina Kostopoulos, Vassilis Pakos, Emilios E. Fotiadis, Dimitrios I. University of Ioannina Unit of Medical Technology and Intelligent Information Systems Dept. of Materials Science and Engineering IoanninaGR45110 Greece University of Patras Laboratory of Biomechanics and Biomedical Engineering Dept. of Mechanical Engineering and Aeronautics RionGR26500 Greece University of Patras Dept of Agriculture MessolonghiGR30200 Greece University of Patras Dept. of Mechanical Engineering and Aeronautics Rio Achaia26504 Greece University of Ioannina School of Medicine Department of Orthopaedic Surgery and Traumatology Epirus Ioannina45221 Greece University of Ioannina Unit of Medical Technology and Intelligent Information Systems Dept. of Materials Science and Engineering Biomedical Research Institute-FORTH GR45110 Greece

ISBN: (纸本)9798350371499

This study aims to comprehensively evaluate the mechanical performance of bone scaffolds, focusing on a compression test displacement rate 0.5mm/s and 2mm/min. The research employs the Yeoh 3rd order model for the hyperelastic PLA scaffolds to simulate the compression tests, which are validated using experimental results. More specifically, the stress- strain curves derived from the in-silico analysis exhibit strong agreement with the experimental results, highlighting the reliability of the computational approach. Two distinct scaffold geometries were employed and a comparative analysis of their responses to specific loading conditions had been performed. The investigation reveals that the PCL-50 scaffold demonstrates promising mechanical behavior in terms of better endurance in such loading conditions. © 2024 IEEE.

关键词： Stress-strain curves

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Effect of Organic Long Persistent Luminescence on Hole Transport Material-Free Perovskite Solar Cell

Effect of Organic Long Persistent Luminescence on Hole Trans...

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2023 International Conference on Power and Renewable Energy engineering, PREE 2023

作者： Sharma, Tejas Soo, Yew Hang Ng, Chai Yan Jun, H.K. Universiti Tunku Abdul Rahman Lee Kong Chian Faculty of Engineering & Science Dept. of Mechanical & Materials Engineering Kajang Malaysia Universiti Tunku Abdul Rahman Centre for Photonics and Advanced Materials Research Kajang Malaysia

ISBN: (纸本)9798350321906

This work focuses on the study of perovskite materials as the active component in perovskite solar cells (PSCs). Hole transport material-free PSCs consisting of perovskite MAPbI3 and FAMAPbI3 were fabricated under ambient conditions. To enhance the functionality of PSCs, a mixture of organic long persistent luminescence (LPL) materials, namely TMB and PPT, and an inorganic LPL material, strontium aluminate doped with europium and dysprosium (SrAl2O3), were integrated into the cell structure, allowing operation in the low light conditions. The afterglow effect observed in the LPL materials was investigated in relation to its impact on the solar cell performance. Specifically, the influence of mixed organic LPL materials on the optical properties was examined. The results showed that an LPL mixture with TMB:PPT = 7:3 (by mass) exhibited the highest photoluminescence (PL) response. The integration of LPL materials presents a novel approach to enable PSCs to operate with improved performances. Additionally, the power conversion efficiency of three different setups of PSCs was evaluated. The findings revealed that PSCs with the inorganic LPL material achieved improved performance attributed to the light down-conversion effect. © 2023 IEEE.

关键词： Photoluminescence

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On Importance of Start Transient Current Measurement for Health Monitoring of Aerospace Solenoid Valves

On Importance of Start Transient Current Measurement for Hea...

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2024 IEEE Silchar Subsection Annual Conference, SILCON 2024

作者： Sidhartha, P.A.V. Verma, Arnika Sai N, Venkata Sunil Chakrabarti, Subrata Sahoo, Balaram Kumar, Aloke Liquid Propulsion Systems Centre Indian Space Research Organisation Trivandrum India Materials Research Centre Indian Institute of Science Bangalore India Indian Institute of Science Dept. of Mechanical Engineering Bangalore India

ISBN: (纸本)9798331540821

Solenoid valves form an integral part of aerospace systems. They primarily find application as thruster on-off valves for propellant flow control during steady state and pulse width modulation (PWM) operation of spacecraft thrusters. Electromechanical transient characteristics (ETC) of the sole-noid valves decide the overall system response of the thruster. ETC can be a powerful tool for performance characterization, prediction, health monitoring and failure analysis in solenoid valves. Several tools are used for deducing the ETC in solenoid valves. Important among them are finite element method (FEM) based and analytical multi-physics based models to name a few. FEM can be time consuming. Multi-physics based models are generally very exhaustive. However, simulations need to be validated by elaborate mechanical measurements of plunger stroke, velocity, electromagnetic force etc. This calls for high accuracy measurement arrangements to be made. It turns out that measurement of coil current alone can be an ideal replacement for all the above which can help in correctly characterising the performance of a solenoid valve. © 2024 IEEE.

关键词： Solenoid valves

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Formal Verification of a Nuclear Plant Thermal Dispatch Operation Using System Decomposition

Formal Verification of a Nuclear Plant Thermal Dispatch Oper...

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IEEE International Conference on Trust, Privacy and Security in Intelligent Systems and Applications (TPS-ISA)

作者： Abhimanyu Kapuria Daniel G. Cole Dept. of Mechanical Engineering and Materials Science University of Pittsburgh Pittsburgh USA

ISBN: (数字)9798350386745

ISBN: (纸本)9798350386752

This paper discusses methods to prove the safety of critical cyber-physical systems. Critical infrastructure, such as nuclear power plants, are prone to vulnerabilities due to the integration of industrial internet-of-things technologies. Automation and computation introduces greater complexity into these systems. Thus, traditional safety analysis methods, including probabilistic risk assessment and system theoretic process analysis, can be limited in their scope of analysis, specifically in addressing software vulnerabilities and the cyber-physical interface. To address these limitations, we propose an approach to safety analysis by integrating multiple formal verification methods within the context of hybrid systems. This approach employs a combination of reachability analysis and theorem proving, specifically using differential dynamic logic (dℒ), to model and verify the safety of a nuclear plant’s thermal dispatch operation. By decomposing the system into individual components, our method reduces computational complexity and enhances the verification process, ensuring the resiliency of critical infrastructure against potential hazards. This integrated approach offers a comprehensive framework for the safety and security of complex, cyber-physical systems.

关键词： Analytical models Thermal decomposition Cyber-physical systems Safety Thermal analysis Critical infrastructure Security Reachability analysis Resilience Formal verification

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Nanoscale-precipitate-strengthened (Ni,Cu)-rich TiNiCu shape memory alloy with stable superelasticity and elastocaloric performance

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Journal of Alloys and Compounds 2024年 997卷

作者： Hsu, Yi-Ting Wu, Cheng-Tien Chen, Chih-Hsuan Dept. of Materials Science and Engineering National Taiwan University Taipei106 Taiwan Dept. of Mechanical Engineering National Taiwan University Taipei106 Taiwan

This study aimed to enhance the stability of the superelastic and elastocaloric properties of a Ti49Ni41Cu10 shape memory alloy through a synergistic approach combining compositional design and precipitation hardening. The alloy was subjected to a 168-h aging treatment at 400 °C. The aging treatment increased the hardness of the alloy due to the formation of nano-scale C11b Ti(Ni,Cu)2 precipitates. The C11b Ti(Ni,Cu)2 precipitates exhibited a coherent interface with the matrix, contributing to the significant strengthening effect. The thickness of the precipitates was measured to be approximately 2 nm. Additionally, the lattice compatibility between the B2 parent and B19 martensite phases, determined to be 0.997 after aging, indicated a high level of compatibility between the two phases. The high compatibility and precipitate strengthening further contributed to the functional stability of the alloy. The 168-h aged Ti49Ni41Cu10 shape memory alloy showed excellent functional stability during thermal and deformation cycles. The peak temperature of B2 to B19 transformation only decreased by 0.2 °C after 10 thermal cycles and showed limited changes with a decrement of 3.2 °C after 10,000 superelastic cycles. The Ti49Ni41Cu10 SMA showed a large elastocaloric temperature drop of 18 °C at the 1st superelastic cycle and maintained a large temperature drop of 17 °C after 1000 cycles. These findings contribute to a deeper understanding of the microstructural changes and their impact on the functional properties of the Ti49Ni41Cu10 shape memory alloy. This study has demonstrated the potential for developing shape memory alloys with improved stability and performance by utilizing compositional design and precipitation hardening techniques. © 2024 Elsevier B.V.

关键词： Precipitation (chemical)

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On the Development of a Testing Device for Fracture Characterization under Mixed-Mode Loading Conditions

On the Development of a Testing Device for Fracture Characte...

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2021 ASTM International Symposium on Advances in Accelerated Testing and Predictive Methods in Creep, Fatigue, and Environmental Cracking

作者： Oskui, Abuzar Es'Haghi Ebrahimi, Mahmoud Attarilar, Shokouh Wang, Qudong Choupani, Naghdali Djavanroodi, Faramarz Dept. of Mechanics and Aerospace Engineering Southern University of Science and Technology Shenzhen518055 China National Engineering Research Center of Light Alloy Net Forming State Key Laboratory of Metal Matrix Composites School of Materials Science and Engineering Shanghai Jiao Tong University Shanghai200240 China Dept. of Mechanical Engineering Gebze Technical University Kocaeli41400 Turkey Mechanical Engineering Dept. Prince Mohammad Bin Fahd University Al Khobar31952 Saudi Arabia

ISBN: (纸本)9780803177338

Because there is no codified standard for a mixed-mode fracture test, this study, by summing up previous works and investigating their properties, attempts to provide the requirements for standardization of mixed-mode fracture testing. Utilizing the loading device proposed in the present paper can help avoid the drawbacks of the previous methods applied for testing fracture toughness under mixed-mode conditions. The proposed fixture has a perfect symmetry that provides pure in-plane circumstances, preventing undesired third-mode loading conditions and creating a uniform stress state. The three-dimensional finite element models of the Arcan fixture and the suggested loading device were used to obtain the correction factors for the first and second modes. The results were then compared to investigate the variations of the fracture parameters. Moreover, analysis of the dimensionless stress intensity factors (SIFs) obtained for the third mode at various angles of loading led to the conclusion that the unwanted thirdmode loading conditions had a considerable contribution to the Arcan device and, as a result, influenced the values achieved for the first- and second-mode dimensionless SIFs. © 2023 by ASTM International.

关键词： Fracture toughness

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Every Click You Make, Every Break You Take, We'll be Watching You

Every Click You Make, Every Break You Take, We'll be Watchin...

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Frontiers in Education (FIE) Conference

作者： David M. Pabst Lucas J. Zwastetzky Kristian A. Borysiak Lee A. Dosse Matthew M. Barry Dept. of Mechanical Engineering and Materials Science University of Pittsburgh Pittsburgh PA USA

ISBN: (数字)9798350351507

ISBN: (纸本)9798350363067

This research-based full paper investigates Pre-recorded Lecture Video (PLV) viewership habits and elucidates correlations between practice and course performance. Using PLVs and Flipped Class Formats (FCFs) is increasingly prevalent in colleges and universities, driven by various motivating factors. Delivering content that was traditionally done didactically in a format that is both accessible and engaging has many benefits to not only the students but also instructors. For example, students can review PLVs multiple times at their convenience until they understand the material. From an instructional standpoint, PLVs and FCFs allow for more classroom interaction, whether through instructor-led examples or peer-to-peer learning activities. As with any new instructional technique, there are best practices that maximize both student performance and satisfaction, often guided by research. Previous studies have investigated both student use and interaction mechanisms of PLVs, specifically their level of viewership and completion of conceptual check-point questions that could be answered while or after watching assigned videos. Students who had substantial viewership and interacted with the PLVs by answering questions witnessed a statistically significant increase in their course grades compared to those who did not. However, viewership and interaction with a PLV do not tell the whole story. To this end, it is crucial to understand how students use PLVs, specifically, what habits they form while watching PLVs and how this behavior affects their performance in the course. During two years, 445 students enrolled in a sophomore-level Statics and Mechanics of materials course were instructed using PLVs and an FCF. The students were required to view PLVs before class (on the University's approved Learning Management System, Canvas, using Panopto) and answer basic conceptual questions on Top Hat. Student viewership data (date and time watched, minutes delivered, etc.) was colle

关键词： Over-the-top media services Learning management systems Correlation Reviews Media Timing Peer-to-peer computing Standards Monitoring Best practices

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