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Material Design and Processing Communications 2021年第4期3卷

作者： Raheem, Hassan Mansour Al-Mukhtar, Ahmed M. Mechanical Department Faculty of Engineering University of Kufa Najaf Iraq Ministry of Oil Midland Refineries Company Karbala Refinery Karbala Iraq Biomedical Engineering Dept. College of Engineering University of Warith Alanbiyaa Baghdad Iraq Vff TUBA Freiberg Freiberg Germany

Hydrogels are viscoelastic material, soft and fragile materials that contain high water percent. These properties cannot sustain high axial compression loads. In this study, a foam was infused into hydrogel, agarose, to enhance the mechanical properties of the hydrogel/foam composite. Besides, it is difficult to measure the mechanical properties of the hydrogel alone specifically in tension because of the slipping in the grip during using the common tensile test. Therefore;the goal of this study is to investigate the influences of infused cellulose foam into the prepared hydrogels on the mechanical properties of the hydrogels by conducting the unconfined compression on hydrogel/foam composite and the hydrogel alone. It is also to utilize the strain energy density functions (SEDFs) to determine a suitable constitutive model that represents the nonlinear behavior of the materials. It is to predict the behavior of these materials out of range of the test (i.e., in tension) by implementing a finite elements analysis (FEA) using ABAQUS. The results showed that the strength of the hydrogel/foam composite was significantly greater than hydrogel alone. All hyperelastic models have well defined the nonlinear behavior of the experimental data. FEA results in tension are in good agreement with those predicted using hyperelastic models. © 2020 John Wiley & Sons, Ltd.

关键词： Hydrogels

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All-Aerosol-Sprayed High-Performance Transparent Triboelectric Nanogenerator with Embedded Charge-Storage Layer for Self-Powered Invisible Security Iot System and Raindrop-Solar Hybrid Energy Harvester

SSRN

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SSRN 2022年

作者： Kim, BaekGyu Song, Jin Yeong Kim, Do Young Lin, Zong-Hong Choi, Dongwhi Park, Sang Min School of Mechanical Engineering Pusan National University 2 Busandaehak-ro 63 Beon-Gil Geumjeong-gu Busan46241 Korea Republic of Institute of Biomedical Engineering Department of Power Mechanical Engineering Frontier Research Center on Fundamental and Applied Sciences of Matters National Tsing Hua University Hsinchu30013 Taiwan Kyung Hee University 1732 Deogyeong-daero Giheung-gu Gyeonggi-do Yongin-si17104 Korea Republic of

Practical utilization of the triboelectric nanogenerators (TENGs), which have unique advantageous aspects of a simple operation mechanism, material selection diversity, and high energy conversion efficiency, requires high functionality as well as its scalable fabrication to broaden the applicable fields. Here, we report the concept of all-aerosol-sprayed transparent TENG (ST-TENG) by sequentially spraying total three layers of silver nanowire conductive layer, transparent polystyrene charge-storage layer, and fluoropolymer contact layer. All layers were achieved by aerosol spray process, thereby exhibiting high design flexibility enough to fabricate ST-TENGs on various pre-made commercial devices. The presence of the transparent polystyrene layer as a charge storing interlayer significantly enhances the power density of the ST-TENG up to 818 mW/m2. As proof-of-concept applications, a self-powered invisible security internet-of-things system, which could blend with the surroundings, exploited biomechanical energy from foot-step for energy harvesting and invasion sensing. Furthermore, by exploiting the all-aerosol-spray process and high light transmittance of the ST-TENG, a hybrid energy harvester to simultaneously generate electricity from solar and raindrop energy was directly fabricated on a commercial solar panel. This work provides the brand-new concept of TENG with a scalable fabrication process, enhanced performance, and outstanding light transmittance. © 2022, The Authors. All rights reserved.

关键词： Nanogenerators

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Gas vesicle isolated from microorganisms to act as ultrasound contrast agent

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Research on biomedical engineering 2021年第1期37卷 1-7页

作者： Garrute, Felipe Vianna Machado, João Carlos Biomedical Engineering Program-COPPE Federal University of Rio de Janeiro Horácio Macedo Ave. 2030 Center of Technology Block H Room 327 Rio de JaneiroRJ21941-914 Brazil Post-graduate Program in Surgical Sciences Department of Surgery School of Medicine Federal University of Rio de Janeiro Carlos Chagas Filho Ave. 373 Health Sciences Center Block K Room 49 Rio de JaneiroRJ21941-902 Brazil

Purpose: Ultrasound contrast agent (UCA), used to enhance the contrast in ultrasonography, consists of microbubbles filled with an inert gas and encapsulated with a protein or a lipidic-stabilize membrane. The UCAs are able to resonate when exposed to ultrasound waves and to generate an echo-acoustic signal with increased intensity. Recently, a technique to produce UCA from microorganisms was developed and it consists of lysing microorganism cells to obtain gas vesicle (GV) after cultivation in the laboratory. GVs occur almost exclusively in aquatic microorganisms, as Microcystis aeruginosa (MYC), and provide buoyancy which permit to float towards the water surface. This work implemented a technique to produce GVs from MYC, at the Ultrasound Laboratory, and inspected their properties of acting as UCAs, analyzed through ultrasonic images acquired at 40 MHz, and their structural characteristics such as morphology, diameter, and length. Methods: After the cultivation of MYC, the buoyant cells with GVs were separated from the culture medium and submitted to cell lysis with chemical treatment. Thereafter, the solution with lysed cells was centrifuged, at 300g during 8 h at 4–8 °C, to isolate the GVs (absorbance 0.6, λ = 500 nm). Results: Transmission electron microscopy inspection revealed the MYC-GVs with elliptical morphology and having a diameter between 100 and 150 nm and length near to 200 nm. B-mode ultrasound images of the solutions proved the GV’s ability to generate an echo signal, thus confirming their performance as UCAs. © 2020, Sociedade Brasileira de Engenharia Biomedica.

关键词： Cytology

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Spectroscopic and Interferometric Sum-Frequency Imaging of Strongly Coupled Phonon Polaritons in SiC Metasurfaces

arXiv

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arXiv 2023年

作者： Niemann, Richarda Mueller, Niclas S. Wasserroth, Sören Lu, Guanyu Wolf, Martin Caldwell, Joshua D. Paarmann, Alexander Fritz-Haber-Institut der Max-Planck-Gesellschaft Faradayweg 4-6 Berlin14195 Germany Department of Mechanical Engineering Vanderbilt University NashvilleTN37235 United States Interdisciplinary Materials Science Graduate Program Vanderbilt University NashvilleTN37235 United States

Phonon polaritons enable waveguiding and localization of infrared light with extreme confinement and low losses. The spatial propagation and spectral resonances of such polaritons are usually probed with complementary techniques such as near-field optical microscopy and far-field reflection spectroscopy. Here, we introduce infrared-visible sum-frequency spectro-microscopy as a tool for spectroscopic imaging of phonon polaritons. The technique simultaneously provides sub-wavelength spatial resolution and highly-resolved spectral resonance information. This is implemented by resonantly exciting polaritons using a tunable infrared laser and wide-field microscopic detection of the upconverted light. We employ this technique to image hybridization and strong coupling of localized and propagating surface phonon polaritons in metasurfaces of SiC micropillars. Spectro-microscopy allows us to measure the polariton dispersion simultaneously in momentum space by angle-dependent resonance imaging, and in real space by polariton interferometry. Notably, we directly visualize how strong coupling affects the spatial localization of polaritons, inaccessible with conventional spectroscopic techniques. We further observe the formation of edge states at excitation frequencies where strong coupling prevents polariton propagation into the metasurface. Our approach is applicable to the wide range of polaritonic materials with broken inversion symmetry and can be used as a fast and non-perturbative tool to image polariton hybridization and propagation. © 2023, CC BY.

关键词： Polariton

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Biomechanical behaviour and hyperelastic model parameters identification of sheep omasum

Research Square

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Research Square 2021年

作者： Lebea, Lebogang Ngwangwa, Harry Pandelani, Thanyani Nemavhola, Fulufhelo Unisa Biomedical Engineering Research Group Department of Mechanical Engineering School of Engineering College of Science Engineering and Technology University of South Africa Pretoria0001 South Africa Defence and Security Council for Scientific and Industrial and Research Pretoria001 South Africa

The function of the omasum is incompletely understood;however, the omasum plays an important role in the transport of appropriately sized feed particles from the reticulorumen to the abomasum, oesophageal groove closure, fermentation of ingesta, and absorption of water, volatile fatty acids, and minerals. The aim of this study is to evaluate the suitable hyperelastic anisotropic model based on biomechanical properties of sheep omasum. The results show that all five (5) hyperelastic models may be suitable for the evaluation of sheep omasum. The average coefficient of determination (R2) of Fung, Polynomial (Anisotropic), Holzapfel (2000), Holzapfel (2005) and Four-Fiber-Family hyperelastic models were found to be 0.79 ± 0.19, 0.95 ± 0.05, 0.92 ± 0.07, 0.93 ± 0.05 and 0.94 ± 0.03, respectively. Also, it was found that the best hyperelastic model for fitting uniaxial data of the sheep omasum was Polynomial (Anisotropic) with EI of 100.0 followed by the Four-Fiber-Family model with EI of 96.18. © 2021, CC BY.

关键词： Volatile fatty acids

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Microfluidic generation of water-in-water-in-water(-in-water) double and triple emulsions 24

Microfluidic generation of water-in-water-in-water(-in-water...

引用

24th International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2020

作者： Jeyhani, Morteza Thevakumaran, Risavarshni Abbasi, Niki Hwang, Dae Kun Tsai, Scott S.H. Department of Mechanical and Industrial Engineering Ryerson University Toronto Canada Keenan Research Centre for Biomedical Science St. Michael's Hospital Toronto Canada -a Partnership Between Ryerson University St. Michael's Hospital Toronto Canada Department of Electrical Computer and Biomedical Engineering Ryerson University Toronto Canada Department of Chemical Engineering Ryerson University Toronto Canada

ISBN: (纸本)9781733419017

Microfluidically generated higher order emulsions are used in a wide range of applications in biomedicine and biology. Conventional droplet generation platforms use organic solvents to fabricate higher order emulsions, but they have biocompatibility issues due to the interaction between biological materials and organic solvents. To overcome these issues, some researchers propose using aqueous two-phase systems (ATPS) to generate biocompatible higher order emulsions in microfluidics [1]. © 2020 CBMS-0001

关键词： Solvent extraction

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Data-driven Modeling of the mechanical Behavior of Anisotropic Soft Biological Tissue

arXiv

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arXiv 2021年

作者： Tac, Vahidullah Sree, Vivek D. Rausch, Manuel K. Tepole, Adrian B. School of Mechanical Engineering Purdue University West LafayetteIN United States Department of Aerospace Engineering and Engineering Mechanics University of Texas at Austin AustinTX United States Weldon School of Biomedical Engineering Purdue University West LafayetteIN United States

Constitutive models that describe the mechanical behavior of soft tissues have advanced greatly over the past few decades. These expert models are generalizable and require the calibration of a number of parameters to fit experimental data. However, inherent pitfalls stemming from the restriction to a specific functional form include poor fits to the data, non-uniqueness of fit, and high sensitivity to parameters. In this study we design and train fully connected neural networks as material models to replace or augment expert models. To guarantee objectivity, the neural network takes isochoric strain invariants as inputs, and outputs the value of strain energy and its derivatives with respect to the invariants. Convexity of the material model is enforced through the loss function. Direct prediction of the derivative functions -rather than just predicting the energy- serves two purposes: it provides flexibility during training, and it enables the calculation of the elasticity tensor through back-propagation. We showcase the ability of the neural network to learn the mechanical behavior of porcine and murine skin from biaxial test data. Crucially, we show that a multi-fidelity scheme which combines high fidelity experimental data with low fidelity analytical data yields the best performance. The neural network material model can then be interpreted as the best extension of an expert model: it learns the features that an expert has encoded in the analytical model while fitting the experimental data better. Finally, we implemented a general user material subroutine (UMAT) for the finite element software Abaqus and thereby make our advances available to the broader computational community. We expect that the methods and software generated in this work will broaden the use of data-driven constitutive models in biomedical applications. Copyright © 2021, The Authors. All rights reserved.

关键词： Constitutive models

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Effects of additional hydrogen and biodiesel crude palm oil on performance and exhaust gas emissions of one cylinder diesel engine

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AIP Conference Proceedings 2023年第1期2630卷

作者： Kuntang Winangun Atok Setiyawan Bambang Sudarmanta Mechanical Engineering Department Institut Teknologi Sepuluh Nopember Surabaya Indonesia 60111 Mechanical Engineering Study Program Universitas Muhammadiyah Ponorogo Ponorogo Indonesia 63471

The scarcity of fuel oil is caused by the increasing demand for fuel oil, and production at the refineries begins to decrease. Making researchers look for solutions, one of which is new and renewable energy. New and renewable energy can be produced sustainably, such asbiodiesel Crude Palm Oil (CPO), and hydrogen gas. The use of CPO biodiesel is known to be low in emissions, high in oxygen content, and cetane number. However, the use of biodiesel without engine modification can lead to decreased thermal efficiency and increased smoke emissions in the engine. The addition of hydrogen gas in small amounts can improve the performance of diesel engines. This study aimsto determine the performance and emissions of diesel engines using CPO biodiesel and hydrogen gas as fuel. The engine used is a single-cylinderdiesel engine, direct injection, with a constant speed of 2000rpm. The load variation is 1kW to 4kW with 0.5kW increment interval, and the hydrogen flow variation is (2.5, 5, 7.5, 10) Liters per minute. At high load, the results obtained thermal efficiency of 78.75 percent without hydrogen flowand decreased to 24.09 percent with 10lpm hydrogen flow. Increased biodieselfuel consumption and soot emissions along with the addition of hydrogen flow, at full load.

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Enhancing Knee Contact Force Prediction Using Transformer Networks: A Comparative Study with Lstm and Mlp

SSRN

引用

SSRN 2025年

作者： Xu, Fashu Wang, Junqing Tong, Bingkui Fang, Xuyi Zhang, Hui Deng, Tao Wei, Qu Nie, Yong Li, Kang Department of Orthopedic Surgery West China Biomedical Big Data Center West China Hospital Sichuan University Sichuan Chengdu China Department of Orthopedic Surgery Orthopedic Research Institute West China Hospital Sichuan University Sichuan Chengdu China State Key Laboratory of Robotics Shenyang Institute of Automation Chinese Academy of Sciences Liaoning Shenyang China College of Computer Science Sichuan University Sichuan Chengdu China College of Electrical Engineering Sichuan University Sichuan Chengdu China School of Mechanical Engineering Sichuan University Sichuan Chengdu China

Background and objectiveKnee contact force (KCF) is pivotal in both the study and degenerative pathologies like Knee Osteoarthritis. Traditionally, they are primarily estimated using musculoskeletal modeling and machine learning predictive algorithms. However, musculoskeletal modeling is limited by intricate experimental protocols, prohibitive equipment cost, and scalability challenges. While machine learning methods, though computationally efficient, exhibit suboptimal predictive accuracy. This study innovatively developed a Transformer model for predicting KCF, benchmarked against long short-term memory (LSTM) and multilayer perceptron (MLP) *** comprehensive database was constructed with gait data from 513 participants, incorporating three degrees of freedom of hip, knee flexion/extension, and ankle dorsiflexion/plantarflexion, constituting four input combinations for the models. Contact forces derived from OpenSim served as the ground truth. Root mean square error (RMSE) and coefficient of determination (R2) were used to evaluate the performance of *** results indicated that the Transformer model demonstrated superior performance, achieving a significantly lower mean root mean square error of 0.02 body weight (BW) compared to MLP (0.54 BW) and LSTM (0.45 BW). Furthermore, the mean R2 of the Transformer network (0.99) was markedly superior to that of MLP (0.45) and LSTM (0.58).ConclusionsThe application of Transformer networks significantly improved the accuracy of KCF prediction, addressing the limitations of traditional musculoskeletal modeling and existing machine learning approaches, which was of paramount importance in both clinical practice and biomechanical research. © 2025, The Authors. All rights reserved.

关键词： Mean square error

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Using sio2 hard mask for fabrication of micro fresnel focusing lens for ultrasonic ejectors

Using sio2 hard mask for fabrication of micro fresnel focusi...

引用

National Conference on mechanical engineering and Manufacturing, NCMME 2019

作者： Bui, Tuan-Anh Pan, Min-Chun Wu, Tzon-Han Le, Thanh-Long School of Mechanical Engineering Hanoi University of Science and Technology Viet Nam Department of Mechanical Engineering National Central University Taiwan Graduate Institute of Biomedical Engineering National Central University Taiwan Faculty of Mechnical Engineering Ho Chi Minh City University of Technology VNUHCM Viet Nam Vietnam National University Ho Chi Minh City Viet Nam

ISBN: (纸本)9783035717143

The fabrication of Fresnel focusing lenses operating at frequencies of 100 and 200 MHz was investigated in order to enhance the focusing efficiency of ultrasonic energy. The effects of process parameters on the four-level Fresnel lens profiles were discussed to find a most feasible fabrication procedure through these experiments. The quality of Fresnel lenses was improved when two-and three-mask processes using SiO2 film as the hard mask were employed. Besides, a better side-wall profile of Fresnel lens was obtained by using the three-mask process as compared to the two-mask one. © 2020 Trans Tech Publications Ltd, Switzerland.

关键词： Silica

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