2,260,314 results on '"Mechanical engineering"'
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2. Particle hydrodynamics in acoustic fields: Unifying acoustophoresis with streaming
- Author
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Zhang, Xiaokang, Minten, Jake, and Rallabandi, Bhargav
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Fluid Mechanics and Thermal Engineering ,Engineering ,Applied Mathematics ,Classical Physics ,Mechanical Engineering ,Fluid mechanics and thermal engineering - Published
- 2024
3. Subject-specific one-dimensional fluid dynamics model of chronic thromboembolic pulmonary hypertension
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Kachabi, Amirreza, Colebank, Mitchel J, and Chesler, Naomi C
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Fluid Mechanics and Thermal Engineering ,Engineering ,Biomedical Engineering ,Bioengineering ,Lung ,Cardiovascular ,Aetiology ,2.1 Biological and endogenous factors ,Animals ,Humans ,Hypertension ,Pulmonary ,Pulmonary Embolism ,Hydrodynamics ,Pulmonary Artery ,Hemodynamics ,CTEPH ,1D CFD ,Hemodynamics modeling ,Wall shear stress ,Mechanical Engineering ,Biomedical engineering - Abstract
Chronic thromboembolic pulmonary hypertension (CTEPH) develops due to the accumulation of blood clots in the lung vasculature that obstructs flow and increases pressure. The mechanobiological factors that drive progression of CTEPH are not understood, in part because mechanical and hemodynamic changes in the small pulmonary arteries due to CTEPH are not easily measurable. Using previously published hemodynamic measurements and imaging from a large animal model of CTEPH, we applied a subject-specific one-dimensional (1D) computational fluid dynamic (CFD) approach to investigate the impact of CTEPH on pulmonary artery stiffening, time-averaged wall shear stress (TAWSS), and oscillatory shear index (OSI) in extralobar (main, right, and left) pulmonary arteries and intralobar (distal to the extralobar) arteries. Our results demonstrate that CTEPH increases pulmonary artery wall stiffness and decreases TAWSS in extralobar and intralobar arteries. Moreover, CTEPH increases the percentage of the intralobar arterial network with both low TAWSS and high OSI, quantified by the novel parameter φ , which is related to thrombogenicity. Our analysis reveals a strong positive correlation between increases in mean pulmonary artery pressure (mPAP) and φ from baseline to CTEPH in individual subjects, which supports the suggestion that increased φ drives disease severity. This subject-specific experimental-computational framework shows potential as a predictor of the impact of CTEPH on pulmonary arterial hemodynamics and pulmonary vascular mechanics. By leveraging advanced modeling techniques and calibrated model parameters, we predict spatial distributions of flow and pressure, from which we can compute potential physiomarkers of disease progression. Ultimately, this approach can lead to more spatially targeted interventions that address the needs of individual CTEPH patients.
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- 2024
4. A Systems Approach to Biomechanics, Mechanobiology, and Biotransport.
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Peirce-Cottler, Shayn M, Sander, Edward A, Fisher, Matthew B, Deymier, Alix C, LaDisa, John F, O'Connell, Grace, Corr, David T, Han, Bumsoo, Singh, Anita, Wilson, Sara E, Lai, Victor K, and Clyne, Alisa Morss
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Engineering ,Biomedical Engineering ,Bioengineering ,Quality Education ,Humans ,Biomechanical Phenomena ,Biophysics ,Systems Analysis ,Mechanical Engineering ,Biomedical engineering - Abstract
The human body represents a collection of interacting systems that range in scale from nanometers to meters. Investigations from a systems perspective focus on how the parts work together to enact changes across spatial scales, and further our understanding of how systems function and fail. Here, we highlight systems approaches presented at the 2022 Summer Biomechanics, Bio-engineering, and Biotransport Conference in the areas of solid mechanics; fluid mechanics; tissue and cellular engineering; biotransport; and design, dynamics, and rehabilitation; and biomechanics education. Systems approaches are yielding new insights into human biology by leveraging state-of-the-art tools, which could ultimately lead to more informed design of therapies and medical devices for preventing and treating disease as well as rehabilitating patients using strategies that are uniquely optimized for each patient. Educational approaches can also be designed to foster a foundation of systems-level thinking.
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- 2024
5. ExaWind: Open‐source CFD for hybrid‐RANS/LES geometry‐resolved wind turbine simulations in atmospheric flows
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Sharma, Ashesh, Brazell, Michael J, Vijayakumar, Ganesh, Ananthan, Shreyas, Cheung, Lawrence, deVelder, Nathaniel, de Frahan, Marc T Henry, Matula, Neil, Mullowney, Paul, Rood, Jon, Sakievich, Philip, Almgren, Ann, Crozier, Paul S, and Sprague, Michael
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Fluid Mechanics and Thermal Engineering ,Control Engineering ,Mechatronics and Robotics ,Engineering ,Affordable and Clean Energy ,Electrical and Electronic Engineering ,Mechanical Engineering ,Interdisciplinary Engineering ,Energy ,Electrical engineering ,Environmental engineering - Abstract
Predictive high-fidelity modeling of wind turbines with computational fluid dynamics, wherein turbine geometry is resolved in an atmospheric boundary layer, is important to understanding complex flow accounting for design strategies and operational phenomena such as blade erosion, pitch-control, stall/vortex-induced vibrations, and aftermarket add-ons. The biggest challenge with high-fidelity modeling is the realization of numerical algorithms that can capture the relevant physics in detail through effective use of high-performance computing. For modern supercomputers, that means relying on GPUs for acceleration. In this paper, we present ExaWind, a GPU-enabled open-source incompressible-flow hybrid-computational fluid dynamics framework, comprising the near-body unstructured grid solver Nalu-Wind, and the off-body block-structured-grid solver AMR-Wind, which are coupled using the Topology Independent Overset Grid Assembler. Turbine simulations employ either a pure Reynolds-averaged Navier–Stokes turbulence model or hybrid turbulence modeling wherein Reynolds-averaged Navier–Stokes is used for near-body flow and large eddy simulation is used for off-body flow. Being two-way coupled through overset grids, the two solvers enable simulation of flows across a huge range of length scales, for example, 10 orders of magnitude going from O(μm) boundary layers along the blades to O(10 km) across a wind farm. In this paper, we describe the numerical algorithms for geometry-resolved turbine simulations in atmospheric boundary layers using ExaWind. We present verification studies using canonical flow problems. Validation studies are presented using megawatt-scale turbines established in literature. Additionally presented are demonstration simulations of a small wind farm under atmospheric inflow with different stability states.
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- 2024
6. Bicrystallography-informed Frenkel–Kontorova model for interlayer dislocations in strained 2D heterostructures
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Ahmed, Tusher, Wang, Chenhaoyue, Banerjee, Amartya S, and Admal, Nikhil Chandra
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Civil Engineering ,Engineering ,Materials Engineering ,Mechanical Engineering ,2D materials ,2D heterostructures ,Straintronics ,Interface dislocations ,Strain engineering ,Structural relaxation ,Mechanical Engineering & Transports ,Civil engineering ,Materials engineering ,Mechanical engineering - Published
- 2024
7. Review of state-of-the-art micro and macro-bioreactors for the intervertebral disc
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McKinley, Jonathan P and O'Connell, Grace D
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Engineering ,Biomedical Engineering ,Pain Research ,Bioengineering ,Chronic Pain ,Biotechnology ,Animals ,Humans ,Intervertebral Disc Degeneration ,Quality of Life ,Organ Culture Techniques ,Intervertebral Disc ,Bioreactors ,Bioreactor ,Complex loading ,Disc degeneration ,Intervertebral disc ,Mechanical Engineering ,Human Movement and Sports Sciences ,Biomedical engineering ,Sports science and exercise - Abstract
Lower back pain continues to be a global epidemic, limiting quality of life and ability to work, due in large part to symptomatic disc degeneration. Development of more effective and less invasive biological strategies are needed to treat disc degeneration. In vitro models such as macro- or micro-bioreactors or mechanically active organ-chips hold great promise in reducing the need for animal studies that may have limited clinical translatability, due to harsher and more complex mechanical loading environments in human discs than in most animal models. This review highlights the complex loading conditions of the disc in situ, evaluates state-of-the-art designs for applying such complex loads across multiple length scales, from macro-bioreactors that load whole discs to organ-chips that aim to replicate cellular or engineered tissue loading. Emphasis was placed on the rapidly evolving more customizable organ-chips, given their greater potential for studying the progression and treatment of symptomatic disc degeneration. Lastly, this review identifies new trends and challenges for using organ-chips to assess therapeutic strategies.
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- 2024
8. Physics-informed UNets for discovering hidden elasticity in heterogeneous materials
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Kamali, Ali and Laksari, Kaveh
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Engineering ,Materials Engineering ,Mechanical Engineering ,Biomedical Engineering ,Bioengineering ,Deep learning ,Elasticity imaging ,Model-based elastography ,Tissue biomechanics ,Biomedical engineering ,Materials engineering ,Mechanical engineering - Abstract
Soft biological tissues often have complex mechanical properties due to variation in structural components. In this paper, we develop a novel UNet-based neural network model for inversion in elasticity (El-UNet) to infer the spatial distributions of mechanical parameters from strain maps as input images, normal stress boundary conditions, and domain physics information. We show superior performance - both in terms of accuracy and computational cost - by El-UNet compared to fully-connected physics-informed neural networks in estimating unknown parameters and stress distributions for isotropic linear elasticity. We characterize different variations of El-UNet and propose a self-adaptive spatial loss weighting approach. To validate our inversion models, we performed various finite-element simulations of isotropic domains with heterogenous distributions of material parameters to generate synthetic data. El-UNet is faster and more accurate than the fully-connected physics-informed implementation in resolving the distribution of unknown fields. Among the tested models, the self-adaptive spatially weighted models had the most accurate reconstructions in equal computation times. The learned spatial weighting distribution visibly corresponded to regions that the unweighted models were resolving inaccurately. Our work demonstrates a computationally efficient inversion algorithm for elasticity imaging using convolutional neural networks and presents a potential fast framework for three-dimensional inverse elasticity problems that have proven unachievable through previously proposed methods.
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- 2024
9. Bayesian-Optimized Riblet Surface Design for Turbulent Drag Reduction via Design-by-Morphing with Large Eddy Simulation
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Lee, Sangjoon, Sheikh, Haris Moazam, Lim, Dahyun Daniel, Gu, Grace, and Marcus, Philip S
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Fluid Mechanics and Thermal Engineering ,Engineering ,Mechanical Engineering ,Design Practice and Management ,Design Practice & Management ,Control engineering ,mechatronics and robotics ,Mechanical engineering - Abstract
Abstract: A computational approach is presented for optimizing new riblet surface designs in turbulent channel flow for drag reduction, utilizing Design-by-Morphing (DbM), Large Eddy Simulation (LES), and Bayesian Optimization (BO). The design space is generated using DbM to include a variety of novel riblet surface designs, which are then evaluated using LES to determine their drag-reducing capabilities. The riblet surface geometry and configuration are optimized for maximum drag reduction using the mixed-variable Bayesian optimization (MixMOBO) algorithm. A total of 125 optimization epochs are carried out, resulting in the identification of 3 optimal riblet surface designs that are comparable to or better than the reference drag reduction rate of 8 %. The Bayesian-optimized designs commonly suggest riblet sizes of around 15 wall units, relatively large spacing compared to conventional designs, and spiky tips with notches for the riblets. Our overall optimization process is conducted within a reasonable physical time frame with up to 12-core parallel computing and can be practical for fluid engineering optimization problems that require high-fidelity of computational design before materialization.
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- 2024
10. Unraveling the Highly Plastic Behavior of ALD‐Aluminum Oxide Encapsulations by Small‐Scale Tensile Testing
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Vogl, Lilian M, Schweizer, Peter, Minor, Andrew M, Michler, Johann, and Utke, Ivo
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Engineering ,Materials Engineering ,Nanotechnology ,ALD ,characterization ,EELS ,in situ electron microscopy ,metal oxides ,nanowires ,TEM ,Materials ,Civil engineering ,Materials engineering ,Mechanical engineering - Abstract
We present a study directly measuring the electron‐beam‐induced plasticity of amorphous Al2O3 coatings. Core–shell nanostructures are employed as small‐scale model systems for two‐dimensional coatings made by atomic layer deposition (ALD). Copper nanowires (NWs) are used as substrates for ALD deposition, representing a model system for interconnects commonly found in integrated circuits. Experiments are performed in situ in a transmission electron microscope (TEM) and further analyzed with electron energy loss spectroscopy (EELS). Our in situ TEM tensile experiments reveal the highly plastic behavior of the ALD shell, which withstands a maximum strain of 188%. Comparable samples under beam‐off conditions show a brittle fracture, which underlines the effect of electron irradiation. The electron‐beam‐activated bond switching within the amorphous network enables compensation of the applied tensile strain, leading to viscous flow. By incorporating an intermediate nanocrystalline layer within the Al2O3 shell, the plasticity is suppressed and brittle fracture occurs. This work directly demonstrates the tuning of mechanical properties in amorphous ALD structures through electron irradiation.
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- 2024
11. Hydrogen storage and geo-methanation in a depleted underground hydrocarbon reservoir
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Hellerschmied, Cathrine, Schritter, Johanna, Waldmann, Niels, Zaduryan, Artur B, Rachbauer, Lydia, Scherr, Kerstin E, Andiappan, Anitha, Bauer, Stephan, Pichler, Markus, and Loibner, Andreas P
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Engineering ,Electrical Engineering ,Mechanical Engineering ,Affordable and Clean Energy ,Electrical and Electronic Engineering ,Environmental Engineering ,Electrical engineering ,Mechanical engineering - Abstract
Coupling of power-to-gas processes with underground gas storage could effectively allow surplus electricity to be stored for later use. Depleted hydrocarbon reservoirs could be used as stores, but practical experience of hydrogen storage in such sites is limited. Here we present data from a field trial that stored 119,353 m3 of hydrogen admixed to natural gas in a depleted hydrocarbon reservoir. After 285 days, hydrogen recovery was 84.3%, indicating the process’s technical feasibility. Additionally, we report that microbes mediated hydrogen conversion to methane. In laboratory experiments studying mesocosms that mimic real reservoirs, hydrogen and carbon dioxide were converted to methane (0.26 mmol l−1 h−1 evolution rate) reproducibly over 14 cycles in 357 days. This rate theoretically allows 114,648 m3 of methane per year to be produced in the test reservoir (equivalent to ~1.08 GWh). Our research demonstrates the efficiency of hydrogen storage and the importance of geo-methanation in depleted hydrocarbon reservoirs.
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- 2024
12. Thermochemical data and phase equilibria of halide (Cl−, Br−, I−) containing AFm and hydrotalcite compounds
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Collin, Marie, Prentice, Dale P, Geddes, Dan, Provis, John L, Ellison, Kirk, Balonis, Magdalena, Simonetti, Dante, and Sant, Gaurav N
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Civil Engineering ,Engineering ,AFm ,equilibrium constant ,hydrotalcite ,LDH ,thermodynamic modeling ,Materials Engineering ,Mechanical Engineering ,Materials ,Materials engineering - Abstract
Layered double hydroxide (LDH) phases that form during cement hydration can incorporate a variety of interlayer anions in their interlayer positions. Here, a range of phases of general formula [MII(1−x)MIII(x)(OH)2][An−]x/n·zH2O were synthesized, where MII = Mg2+ (hydrotalcite) or Ca2+ (AFm), MIII = Al3+ such that [MII/Al] = 2 (Ca and Mg, atomic units) or 3 (Mg only), and A = Cl−, Br−, or I−. All the synthesized phases were characterized to assess their composition, density, and crystal structure. By approach from undersaturation, the solubility data of these compounds was measured at 5, 25, and 60°C. This thermochemical data was used to successfully model their formation using thermodynamic modeling and to infer the fields of stability of these compounds for conditions of relevance to cementitious systems. It is seen that halide-containing hydrotalcite phases strongly compete with hydroxide-containing hydrotalcite, with the latter prevailing at high pH. In contrast, halide-containing AFm compounds are more stable compared with hydroxide-containing AFm compositions.
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- 2024
13. Level crossings reveal organized coherent structures in a turbulent time series
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Chowdhuri, Subharthi and Banerjee, Tirtha
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Fluid Mechanics and Thermal Engineering ,Engineering ,Applied Mathematics ,Classical Physics ,Mechanical Engineering ,Fluid mechanics and thermal engineering - Abstract
In turbulent flows, energy production is associated with highly organized structures, known as coherent structures. Since these structures are three dimensional, their detection remains challenging in the most common situation in experiments, when single-point temporal measurements are considered. While previous research on coherent structure detection from time series employs a thresholding approach, either in spectral or temporal domain, the thresholds are ad hoc and vary significantly from one study to another. To circumvent this issue, we introduce the level-crossing method and show how specific features of a turbulent time series associated with coherent structures can be objectively identified, without assigning a priori any arbitrary threshold. By using two wall-bounded turbulence time-series datasets (at a Reynolds number of 104), we successfully extract through level-crossing analysis the impacts of coherent structures on turbulent dynamics and therefore open an alternative avenue in experimental turbulence research. By utilizing this framework further, we discover a metric, characterized by a statistical asymmetry between the peaks and troughs of a turbulent signal, to quantify inner-outer interaction in wall turbulence. Most importantly, through phase-randomized surrogate data modeling, we demonstrate that the level-crossing statistics are quite sensitive to the nonlinear dependencies in a turbulent signal. Physically, this finding implies that the large-scale coherent structures modulate the near-wall turbulent dynamics through a nonlinear interaction associated with low-speed streaks, a mechanism not identifiable from spectral analysis alone. Moreover, a connection is established between extreme value statistics and level-crossing analysis, thereby allowing additional possibilities to study extreme events in other dynamical systems.
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- 2024
14. SACSoN: Scalable Autonomous Control for Social Navigation
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Hirose, Noriaki, Shah, Dhruv, Sridhar, Ajay, and Levine, Sergey
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Information and Computing Sciences ,Human-Centred Computing ,Artificial Intelligence ,Clinical Research ,Mechanical Engineering ,Control engineering ,mechatronics and robotics ,Artificial intelligence - Published
- 2024
15. Patellofemoral problems after anterior cruciate ligament reconstruction.
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Sachs, Raymond A, Daniel, Dale M, Ston, Mary Lou, and Garfein, Richard
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patellofemoral ,anterior cruciate ligament reconstruction ,ACL ,knee ligament surgery ,knee ,Biomedical Engineering ,Mechanical Engineering ,Human Movement and Sports Sciences ,Orthopedics ,Clinical sciences ,Allied health and rehabilitation science ,Sports science and exercise - Abstract
Between 1982 and 1986, 126 patients who had undergoneACL reconstruction were followed in a prospectivemanner. One year follow-up statistics were reviewedfor the presence of 13 different complications.The most prevalent complications were quadricepsweakness, flexion contracture, and patellofemoral pain.Quadriceps weakness (strength less than 80% of thenormal side) was present in 65% of patients and correlatedpositively with flexion contracture, patellar irritability,and ACL reconstructions using patellar tendongrafts. Flexion contracture of 5° or more was presentin 24% of patients and correlated positively with increasedage and patellar irritability. Patellofemoral painwas present in 19% of patients and correlated positivelywith flexion contracture.Clinical relevance: The three most common complicationsof knee ligament surgery are shown to bestrongly interrelated. It is likely that a causal relationshipis present in which flexion contracture causes patellofemoralirritability, and that both of these factors, aloneor in combination, result in quadriceps weakness. If thistheory is correct, then it is crucial that postoperativerehabilitation programs place a major emphasis on theavoidance of flexion contracture.
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- 2023
16. The impact of Ancillary Services in optimal DER investment decisions
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Ferreira Cardoso, G, Stadler, M, Mashayekh, S, and Hartvigsson, E
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Microgrid ,Ancillary services ,Decision support tool ,Optimization ,Distributed Energy Resources ,Mixed Integer Linear Programming ,Mechanical Engineering ,Resources Engineering and Extractive Metallurgy ,Interdisciplinary Engineering ,Energy ,Electrical engineering ,Fluid mechanics and thermal engineering ,Mechanical engineering - Abstract
Microgrid resource sizing problems typically include the analysis of a combination of value streams such as peak shaving, load shifting, or load scheduling, which support the economic feasibility of the microgrid deployment. However, microgrid benefits can go beyond these, and the ability to provide ancillary grid services such as frequency regulation or spinning and non-spinning reserves is well known, despite typically not being considered in resource sizing problems. This paper proposes the expansion of the Distributed Energy Resources Customer Adoption Model (DER-CAM), a state-of-the-art microgrid resource sizing model, to include revenue streams resulting from the participation in ancillary service markets. Results suggest that participation in such markets may not only influence the optimum resource sizing, but also the operational dispatch, with results being strongly influenced by the exact market requirements and clearing prices.
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- 2023
17. Controlling the Movement of a TRR Spatial Chain with Coupled Six-bar Function Generators for Biomimetic Motion
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Plecnik, MM and McCarthy, JM
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linkage synthesis ,biomimetic design ,robotic systems ,Manufacturing Engineering ,Mechanical Engineering ,Control engineering ,mechatronics and robotics - Abstract
This paper describes a synthesis technique that constrains a spatial serial chain into a single degree-of-freedom mechanism using planar six-bar function generators. The synthesis process begins by specifying the target motion of a serial chain that is parameterized by time. The goal is to create a mechanism with a constant velocity rotary input that will achieve that motion. To do this we solve the inverse kinematics equations to find functions of each serial joint angle with respect to time. Since a constant velocity input is desired, time is proportional to the angle of the input link, and each serial joint angle can be expressed as functions of the input angle. This poses a separate function generator problem to control each joint of the serial chain. Function generators are linkages that coordinate their input and output angles. Each function is synthesized using a technique that finds 11 position Stephenson II linkages, which are then packaged onto the serial chain. Using pulleys and the scaling capabilities of function generating linkages, the final device can be packaged compactly. We describe this synthesis procedure through the design of a biomimetic device for reproducing a flapping wing motion.
- Published
- 2023
18. Fatigue crack growth in polysilicon microstructures subjected to multi-axial loading: A Poisson–Voronoi-based finite element analysis
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Xu, Rui and Komvopoulos, Kyriakos
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Engineering ,Materials Engineering ,Civil Engineering ,Mechanical Engineering ,Mechanical Engineering & Transports ,Civil engineering ,Materials engineering ,Mechanical engineering - Abstract
Polycrystalline silicon (polysilicon) is the most commonly used structural material of microscopic electromechanical devices, such as sensors and actuators. Almost all of these miniaturized devices contain mechanical elements experiencing high-frequency loading cycles. Due to the rapidly accumulating loading cycles and very small thicknesses of these microstructures, basic understanding of fatigue crack growth in polysilicon at the microscale is critical to the design of durable microdevices that satisfy application requirements. In this investigation, fatigue crack growth in a typical polysilicon microstructure subjected to multi-axial loading was analyzed with the finite element method. To account for the inherent heterogeneity and anisotropy of polysilicon at the microscale, a Poisson-Voronoi tessellation was incorporated in the highly stressed region of the resonating microdevice to model a polycrystalline microstructure. Simulation results illuminated the effect of local texture on the direction and rate of crack growth. Transgranular or intergranular crack growth were predicted, depending on the angle between the crack-path direction and the grain boundary and the fracture resistance of the grain and the grain boundary. From a fundamental fracture mechanics perspective, the computational approach developed in this study provides a capability for examining the effect of local texture anisotropy on cracking in polycrystalline microstructures.
- Published
- 2023
19. Direct in situ measurements of electrical properties of solid–electrolyte interphase on lithium metal anodes
- Author
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Xu, Yaobin, Jia, Hao, Gao, Peiyuan, Galvez-Aranda, Diego E, Beltran, Saul Perez, Cao, Xia, Le, Phung ML, Liu, Jianfang, Engelhard, Mark H, Li, Shuang, Ren, Gang, Seminario, Jorge M, Balbuena, Perla B, Zhang, Ji-Guang, Xu, Wu, and Wang, Chongmin
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Engineering ,Materials Engineering ,Electrical and Electronic Engineering ,Environmental Engineering ,Electrical engineering ,Mechanical engineering - Abstract
The solid-electrolyte interphase (SEI) critically governs the performance of rechargeable batteries. An ideal SEI is expected to be electrically insulative to prevent persistently parasitic reactions between the electrode and the electrolyte and ionically conductive to facilitate Faradaic reactions of the electrode. However, the true nature of the electrical properties of the SEI remains hitherto unclear due to the lack of a direct characterization method. Here we use in situ bias transmission electron microscopy to directly measure the electrical properties of SEIs formed on copper and lithium substrates. We reveal that SEIs show a voltage-dependent differential conductance. A higher rate of differential conductance induces a thicker SEI with an intricate topographic feature, leading to an inferior Coulombic efficiency and cycling stability in Li∣∣Cu and Li∣∣LiNi0.8Mn0.1Co0.1O2 cells. Our work provides insight into the targeted design of the SEI with desired characteristics towards better battery performance.
- Published
- 2023
20. Push-pull locomotion: Increasing travel velocity in loose regolith via induced wheel slip
- Author
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Cao, Cyndia, Moon, Deaho, Creager, Colin, Lieu, Dennis K, and Stuart, Hannah S
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Control Engineering ,Mechatronics and Robotics ,Engineering ,Environmental Engineering ,Mechanical Engineering ,Other Engineering ,Agronomy & Agriculture ,Ecology ,Control engineering ,mechatronics and robotics - Published
- 2023
21. A multi-resolution physics-informed recurrent neural network: formulation and application to musculoskeletal systems
- Author
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Taneja, Karan, He, Xiaolong, He, QiZhi, and Chen, Jiun-Shyan
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Civil Engineering ,Engineering ,Mechanical Engineering ,Musculoskeletal ,Interdisciplinary Engineering ,Applied Mathematics ,Civil engineering ,Mechanical engineering - Abstract
Abstract: This work presents a multi-resolution physics-informed recurrent neural network (MR PI-RNN), for simultaneous prediction of musculoskeletal (MSK) motion and parameter identification of the MSK systems. The MSK application was selected as the model problem due to its challenging nature in mapping the high-frequency surface electromyography (sEMG) signals to the low-frequency body joint motion controlled by the MSK and muscle contraction dynamics. The proposed method utilizes the fast wavelet transform to decompose the mixed frequency input sEMG and output joint motion signals into nested multi-resolution signals. The prediction model is subsequently trained on coarser-scale input–output signals using a gated recurrent unit (GRU), and then the trained parameters are transferred to the next level of training with finer-scale signals. These training processes are repeated recursively under a transfer-learning fashion until the full-scale training (i.e., with unfiltered signals) is achieved, while satisfying the underlying dynamic equilibrium. Numerical examples on recorded subject data demonstrate the effectiveness of the proposed framework in generating a physics-informed forward-dynamics surrogate, which yields higher accuracy in motion predictions of elbow flexion–extension of an MSK system compared to the case with single-scale training. The framework is also capable of identifying muscle parameters that are physiologically consistent with the subject’s kinematics data.
- Published
- 2023
22. Support vector machine guided reproducing kernel particle method for image-based modeling of microstructures
- Author
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Wang, Yanran, Baek, Jonghyuk, Tang, Yichun, Du, Jing, Hillman, Mike, and Chen, Jiun-Shyan
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Civil Engineering ,Engineering ,Mechanical Engineering ,Interdisciplinary Engineering ,Applied Mathematics ,Civil engineering ,Mechanical engineering - Abstract
Abstract: This work presents an approach for automating the discretization and approximation procedures in constructing digital representations of composites from micro-CT images featuring intricate microstructures. The proposed method is guided by the Support Vector Machine (SVM) classification, offering an effective approach for discretizing microstructural images. An SVM soft margin training process is introduced as a classification of heterogeneous material points, and image segmentation is accomplished by identifying support vectors through a local regularized optimization problem. In addition, an Interface-Modified Reproducing Kernel Particle Method (IM-RKPM) is proposed for appropriate approximations of weak discontinuities across material interfaces. The proposed method modifies the smooth kernel functions with a regularized Heaviside function concerning the material interfaces to alleviate Gibb's oscillations. This IM-RKPM is formulated without introducing duplicated degrees of freedom associated with the interface nodes commonly needed in the conventional treatments of weak discontinuities in the meshfree methods. Moreover, IM-RKPM can be implemented with various domain integration techniques, such as Stabilized Conforming Nodal Integration (SCNI). The extension of the proposed method to 3-dimension is straightforward, and the effectiveness of the proposed method is validated through the image-based modeling of polymer-ceramic composite microstructures.
- Published
- 2023
23. Author Correction: Grooved electrodes for high-power-density fuel cells
- Author
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Lee, ChungHyuk, Kort-Kamp, Wilton JM, Yu, Haoran, Cullen, David A, Patterson, Brian M, Arman, Tanvir Alam, Komini Babu, Siddharth, Mukundan, Rangachary, Borup, Rod L, and Spendelow, Jacob S
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Engineering ,Electrical Engineering ,Mechanical Engineering ,Electrical and Electronic Engineering ,Environmental Engineering ,Electrical engineering ,Mechanical engineering - Abstract
Correction to: Nature Energy. Published online 25 May 2023. This paper was originally published under a standard Springer Nature license (© The Author(s), under exclusive licence to Springer Nature Limited). It is now available as an open-access paper under a Creative Commons Attribution 4.0 International license, © The Author(s). The error has been corrected in the online version of the article.
- Published
- 2023
24. Effect of water droplet growth dynamics on electrode current in fuel-cell catalyst layers
- Author
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Petrovick, John G, Radke, Clayton J, and Weber, Adam Z
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Engineering ,Mechanical Engineering ,Affordable and Clean Energy ,Chemical Engineering ,Resources Engineering and Extractive Metallurgy ,Chemical engineering - Abstract
Fuel cells are a promising next-generation energy-conversion technology designed to replace internal combustion engines in transportation applications. However, much work remains to optimize them. Operation at high humidities causes liquid water droplet formation on Pt catalyst particles during oxygen reduction, potentially impeding reactant arrival to the reactive electrode. In this work, four different cases of water droplet growth in fuel-cell catalyst layers are considered: pinned or advancing droplets on a bare Pt surface, advancing droplets on a Nafion film, and water-layer growth in carbon nanopores. Transient drop growth is captured with a combination of mass, species mass, and momentum balances, and the subsequent limiting current is determined via oxygen diffusion and Tafel kinetics. Water droplets are found not to be mass-transfer limiting due to the relatively large liquid-gas area compared to the Pt nanoparticle. Mass-transfer-limited behavior is calculated in carbon nanopores.
- Published
- 2023
25. The effect of Fe-anion interactions on corrosion of ferrous surfaces by phosphonium ionic liquids
- Author
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Liu, Ting, Rahman, Hafizur, Menezes, Pradeep L, and Martini, Ashlie
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Civil Engineering ,Engineering ,Materials Engineering ,Mechanical Engineering ,Energy ,Civil engineering ,Materials engineering ,Mechanical engineering - Published
- 2023
26. The role of peer influence in rooftop solar adoption inequity in the United States
- Author
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O'Shaughnessy, Eric, Grayson, Alexandra, and Barbose, Galen
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Economics ,Applied Economics ,Solar ,Adoption equity ,Social influence ,Peer effects ,Applied economics ,Banking ,Econometrics ,Electrical and Electronic Engineering ,Energy ,finance and investment ,Mechanical Engineering ,Banking ,finance and investment - Abstract
Individual demand for emerging technologies can be influenced by the demand of other individuals within defined peer groups. These so-called peer effects have been demonstrated in emerging clean energy technologies such as rooftop solar. To date, peer effects have disproportionately driven solar adoption among relatively affluent households. Here, we use household-level income estimates of rooftop solar adopters to explore how peer effects drive adoption for low-income households. We find evidence of peer effects for both high- and low-income households and find that peer effects are generally stronger within than across income groups. Our results indicate that peer effects translate to adoption less frequently among low-income households. These results suggest that low-income peer effects are mitigated by barriers to low-income adoption. Heterogeneous peer influence is another demand shifter that explains the inequitable adoption of emerging technologies.
- Published
- 2023
27. Validation of a Low-Cost Portable Device for Inducing Noninvasive Anterior Cruciate Ligament Injury in Mice.
- Author
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Jbeily, Elias H, Lin, Yu-Yang, Elmankabadi, Seif B, Osipov, Benjamin, June, Ron K, and Christiansen, Blaine A
- Subjects
Arthritis ,Osteoarthritis ,Physical Injury - Accidents and Adverse Effects ,Bioengineering ,Aging ,Injuries and accidents ,Musculoskeletal ,Mice ,Animals ,Anterior Cruciate Ligament Injuries ,Joint Instability ,X-Ray Microtomography ,Biomedical Engineering ,Mechanical Engineering - Abstract
Noninvasive compression-induced anterior cruciate ligament rupture (ACL-R) is an easy and reproducible model for studying post-traumatic osteoarthritis (PTOA) in mice. However, equipment typically used for ACL-R is expensive, immobile, and not available to all researchers. In this study, we compared PTOA progression in mice injured with a low-cost custom ACL-rupture device (CARD) to mice injured with a standard system (ElectroForce 3200). We quantified anterior-posterior (AP) joint laxity immediately following injury, epiphyseal trabecular bone microstructure, and osteophyte volume at 2 and 6 weeks post injury using micro-computed tomography, and osteoarthritis progression and synovitis at 2 and 6 weeks post injury using whole-joint histology. We observed no significant differences in outcomes in mice injured with the CARD system compared to mice injured with the Electroforce (ELF) system. However, AP joint laxity data and week 2 micro-CT and histology outcomes suggested that injuries may have been slightly more severe and PTOA progressed slightly faster in mice injured with the CARD system compared to the ELF system. Altogether, these data confirm that ACL-R can be successfully and reproducibly performed with the CARD system and that osteoarthritis (OA) progression is mostly comparable to that of mice injured with the ELF system, though potentially slightly faster. The CARD system is low cost and portable, and we are making the plans and instructions freely available to all interested investigators in the hopes that they will find this system useful for their studies of OA in mice.
- Published
- 2023
28. Dynamics of acoustically coupled single- and multi-port jet diffusion flames
- Author
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Vargas, Andres, Kiani, Sarina, Hayrapetyan, Arin, and Karagozian, AR
- Subjects
Engineering ,Mechanical Engineering ,Automotive Engineering ,combustion ,flames ,laminar reacting flows ,Mathematical Sciences ,Fluids & Plasmas ,Mathematical sciences - Abstract
The present experimental study investigated the dynamics of single- and multi-port gaseous jet diffusion flames exposed to acoustic excitation via a standing wave situated in a closed waveguide at atmospheric pressure. High-speed imaging of the oscillatory flame was analysed via proper orthogonal decomposition (POD), revealing distinct signatures in both mode shapes and phase portraits for transitions in the acoustically coupled combustion process. For Reynolds numbers between 20 and 100, and for low to moderate forcing amplitudes, the flame exhibited sustained oscillatory combustion (SOC) that was highly coupled to the acoustic forcing. Frequency analysis of the temporal POD modes accurately recovered the forcing frequency and its higher harmonics. At higher forcing amplitudes, a multi-frequency response was observed, resulting from a combination of the forcing frequency and much lower frequency oscillations due to periodic lift-off and reattachment (PLOR) of the flame, preceding a transition to flame blow-off (BO). For both single- and triple-jet flames, transitions from SOC to PLOR to BO were characterized by significant alterations in primary modal energetic content, deflection and eventual smearing in phase portraits, and the development of additional frequencies in modal spectra, although transitional behaviour for the triple jet flames involved additional complexity in the dynamics due to its structure. These features provide the potential for the development of reduced-order models that can characterize and predict acoustically coupled combustion behaviour.
- Published
- 2023
29. Solubility behavior and thermodynamic modeling of sodium monosulfoaluminate (“U‐phase”) in cementitious systems
- Author
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Collin, Marie, Prentice, Dale P, Arnold, Ross R, Ellison, Kirk, Balonis, Magdalena, Simonetti, Dante, and Sant, Gaurav N
- Subjects
Engineering ,Materials Engineering ,sodium monosulfate ,solubility constant ,thermodynamic modeling ,U-phase ,Mechanical Engineering ,Materials ,Materials engineering - Abstract
The “U-phase,” a sodium-containing (alumino-ferrite-monosubstituent) AFm phase, has been observed to form in sodium-enriched highly alkaline cementitious systems, for example, of relevance to nuclear waste, and saline industrial brine management. But, minimal information is available of the U-phase's (e.g., solubility or thermodynamic properties) due to its limited stability and its tendency to transform into ettringite or monosulfoaluminate. Herein, the U-phase was systematically synthesized at four temperatures (5, 15, 25, and 50°C) and fully characterized in terms of its thermochemical properties. The average composition of the synthesized U-phase (4CaO·Al2O3·1.85SO3·0.85Na2O·12H2O) deviates slightly from typical disclosures in the literature. The solubility product of the U-phase formation was measured from conditions of oversaturation. The measured thermodynamic data accurately predicted experimental observations of U-phase formation in cementitious environments. In general, it was noted that the U-phase forms and persists (i.e., remains stable) at pH > 13.7 and [Na+] concentrations superior to 1 mol/L.
- Published
- 2023
30. Energetic contributions to deformation twinning in magnesium
- Author
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Kapan, Enver, Alkan, Sertan, Aydıner, C Can, and Mason, Jeremy K
- Subjects
Engineering ,Materials Engineering ,molecular dynamics ,magnesium ,twinning ,nucleation ,Materials ,Materials engineering ,Mechanical engineering - Abstract
Modeling deformation twin nucleation in magnesium has proven to be a challenging task. In particular, the absence of a heterogeneous twin nucleation model which provides accurate energetic descriptions for twin-related structures indicates a need to more deeply understand twin energetics. To address this problem, molecular dynamics simulations are performed to follow the energetic evolution of { 10 1 ‾ 2 } tension twin embryos nucleating from an asymmetrically-tilted grain boundary. The line, surface and volumetric terms associated with twin nucleation are identified. A micromechanical model is proposed where the stress field around the twin nucleus is estimated using the Eshelby formalism, and the contributions of the various twin-related structures to the total energy of the twin are evaluated. The reduction in the grain boundary energy arising from the change in character of the prior grain boundary is found to be able to offset the energy costs of creating the other interfaces. The defect structures bounding the stacking faults that form inside the twin are also found to possibly have significant energetic contributions. These results suggest that both of these effects could be critical considerations when predicting twin nucleation sites in magnesium.
- Published
- 2023
31. 3D fatigue crack path deflection and residual stresses in 17-4PH stainless steel rod
- Author
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Shoemaker, Trevor K, Harris, Zachary D, Smudde, Christine M, Hill, Michael R, and Burns, James T
- Subjects
Engineering ,Materials Engineering ,17-4PH ,Residual stress ,Crack path ,Closure ,Material product form ,Civil Engineering ,Mechanical Engineering ,Mechanical Engineering & Transports ,Civil engineering ,Materials engineering ,Mechanical engineering - Abstract
Damage tolerant structures require accurate fatigue crack growth rate models for life prediction. Central to these models are fracture mechanics similitude and empirically gathered growth rates. In this work, standard test methods failed to achieve similitude for 17-4PH stainless steel round-rod but succeeded for plate. Material product form differences are interrogated through constant ΔK tests, crack path analysis, residual stress (RS) characterization, and growth rate simulation. Analyses revealed that quench-induced RS in the round-rod promoted a non-planar, 3D crack path with closure effects. Strategies to mitigate the RS/path effects are evaluated by controlling constraint, closure, environment, and heat treatment.
- Published
- 2023
32. Barrier-free predictions of short-range ordering/clustering kinetics in binary FCC solid solutions
- Author
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Abu-Odeh, Anas, Uberuaga, Blas Pedro, and Asta, Mark
- Subjects
Physical Sciences ,Condensed Matter Physics ,Kinetics ,Short-range ordering ,Mean-field analysis ,Concentrated alloys ,Binary alloys ,Materials Engineering ,Mechanical Engineering ,Materials ,Materials engineering ,Mechanical engineering ,Condensed matter physics - Abstract
We present comparisons of kinetic Monte Carlo (kMC) simulations of isothermal short-range ordering (SRO) and clustering (SRC) kinetics in binary FCC alloys with a mean-field concentration wave (CW) model. We find that the CW model is able to give order-of-magnitude agreement with kMC simulations for ordering/clustering relaxation times over a wide range of temperatures and compositions. The advantage of the CW model is that it does not require parameterization of vacancy hopping energy barriers, which, for a concentrated alloy, becomes prohibitive. We assess limits in the accuracy of the model, and discuss the effect of cooling rates as well as the extension to multi-component systems. Ultimately, the simplicity and performance of the CW model compared to kMC simulations suggests that it is a useful tool to connect with models of properties dependent on SRO/SRC as well as for designing thermal treatments to control formation of SRO/SRC.
- Published
- 2023
33. Modulating above-room-temperature magnetism in Ga-implanted Fe5GeTe2 van der Waals magnets
- Author
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Yuan, Yanan, Liu, Daxiang, Yu, Jingjing, Zhang, Guanhua, Chen, Xiang, Liu, Ruiqi, Wang, Siyu, Pei, Fangfang, Wei, Long, Li, Zhi, Guo, Junming, Wang, Shouguo, Liao, Zhaoliang, Yan, Wensheng, Qiu, Ziqiang, Yang, Mengmeng, and Li, Qian
- Subjects
Quantum Physics ,Physical Sciences ,Condensed Matter Physics ,Electrical and Electronic Engineering ,Materials Engineering ,Mechanical Engineering ,Materials engineering ,Nanotechnology ,Condensed matter physics - Abstract
The creation of van der Waals (vdW) ferromagnets with tunable Curie temperature (TC) and magnetic anisotropy is essential in developing vdW magnet-based devices. Here, we report an effective and reliable method for modulating the magnetic properties of vdW Fe5GeTe2 by site-specific Ga+ implantation. In this study, we report an easy axis in the ab-plane for bulk Fe5GeTe2 (TC = 310 K) and an axis out of the plane for thin Fe5GeTe2 flakes (TC = 290 K). Combining element-resolved photoemission electron microscopy and spatially resolved magneto-optic Kerr microscopy, we find that the implantation of a tiny amount of 10−3 Ga+·Å−3 in Fe5GeTe2 greatly enhances the TC from 290 to 360 K and switches the magnetic easy axis from the out-of-plane c axis to the ab-plane. The room-temperature x-ray magnetic circular dichroism signal is enhanced from 0% to 9% at an implantation level of 10−2 Ga+·Å−3. These results provide new opportunities for tailoring the magnetic properties of vdW materials beyond room temperature.
- Published
- 2023
34. Single-shot switching in Tb/Co-multilayer based nanoscale magnetic tunnel junctions
- Author
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Mondal, Sucheta, Polley, Debanjan, Pattabi, Akshay, Chatterjee, Jyotirmoy, Salomoni, David, Aviles-Felix, Luis, Olivier, Aurélien, Rubio-Roy, Miguel, Diény, Bernard, Prejbeanu, Liliana Daniela Buda, Sousa, Ricardo, Prejbeanu, Ioan Lucian, and Bokor, Jeffrey
- Subjects
Physical Sciences ,Quantum Physics ,Engineering ,Nanotechnology ,Nanoscale MTJ ,Optical switching ,TMR ,Ferrimagnet ,Magnetic multilayer ,Magneto-optical Kerr effect ,MSD-General ,MSD-Magnetic Materials ,Condensed Matter Physics ,Materials Engineering ,Mechanical Engineering ,Applied Physics ,Materials engineering ,Condensed matter physics - Abstract
Magnetic tunnel junctions (MTJs) are elementary units of magnetic memory devices. For high-speed and low-power data storage and processing applications, fast reversal of the magnetization by an ultrashort laser pulse is extremely important. We demonstrate single-shot switching of Tb/Co-multilayer based nanoscale MTJs by combining the optical writing and the electrical read-out methods. A 90-fs-long laser pulse switches the magnetization of the storage layer (SL). The change in the tunneling magnetoresistance (TMR) between the SL and a reference layer (RL) is probed electrically across the oxide barrier. Single-shot switching is demonstrated by varying the cell diameter from 300 nm to 20 nm. The anisotropy, magnetostatic coupling, and switching probability exhibit cell-size dependence. By suitable association of laser fluence and magnetic field, successive commutation between high-resistance and low-resistance states is achieved. The nature of the magnetization reversal of both SL and RL in a continuous film is probed with a depth-resolved magneto-optical Kerr effect (MOKE) magnetometry. The ultrafast dynamics in the continuous full-MTJ stack is investigated with the time-resolved pump–probe technique. Our experimental findings provide strong support for the growing interest in ultrafast spintronic devices.
- Published
- 2023
35. Diurnal, physics-based strategy for computationally efficient capacity-expansion optimizations for solar-dominated grids
- Author
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ZareAfifi, Farzan, Mahmud, Zabir, and Kurtz, Sarah
- Subjects
Engineering ,Electrical Engineering ,Affordable and Clean Energy ,Capacity expansion models ,Temporal resolution ,Renewable energy ,Computational complexity reduction ,Energy storage ,Critical time step technique ,Mechanical Engineering ,Resources Engineering and Extractive Metallurgy ,Interdisciplinary Engineering ,Energy ,Electrical engineering ,Fluid mechanics and thermal engineering ,Mechanical engineering - Published
- 2023
36. An overview of the tribological and mechanical properties of PEEK and CFR-PEEK for use in total joint replacements
- Author
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Arevalo, Sofia, Arthurs, Claire, Molina, Maria I Echeverria, Pruitt, Lisa, and Roy, Anurag
- Subjects
Bioengineering ,Ketones ,Carbon Fiber ,Polyethylene Glycols ,Ether ,Materials Testing ,Arthroplasty ,Replacement ,Ethyl Ethers ,Ethers ,PEEK ,PEEK composites ,CFR-PEEK ,Tribological properties ,Mechanical properties ,Biocompatibility ,Total joint replacements ,Biomedical Engineering ,Materials Engineering ,Mechanical Engineering - Abstract
Poly-ether-ether-ketone (PEEK) and PEEK composites are outstanding candidates for biomedical applications, such as orthopedic devices, where biocompatibility and modulus match with surrounding tissue are requisite for long-term success. The mechanical properties can be optimized by incorporating fillers such as continuous and chopped carbon fibers. While much is known about the mechanical and tribological behavior of PEEK composites, there are few articles that summarize the viability of using PEEK reinforced with carbon fibers in orthopedic implants. This paper reviews biocompatibility, tribological, and mechanical studies on PEEK and their composites with carbon fibers, notably PEEK reinforced with polyacrylonitrile (PAN)-based carbon fibers and PEEK reinforced with pitch-based carbon fibers, for application in orthopedics and total joint replacements (TJRs). The main objectives of this review are two-fold. Firstly, this paper aims to assist designers in making informed decisions on the suitability of using PEEK and PEEK composites in orthopedic applications; as it is not well understood how these materials perform on the whole in orthopedics and TJRs. Secondly, this paper aims to serve as a centralized paper in which researchers can gain information on the tribological and mechanical advancements of PEEK and PEEK composites.
- Published
- 2023
37. Digitization for reverse engineering: Associated issues and proposed solutions with case studies.
- Author
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Gandhi, Shivam A., Trivedi, Snehal, Patel, Dhaval, and Pandya, Jignesh
- Subjects
- *
REVERSE engineering , *LITERATURE reviews , *ENGINEERING design , *DIGITIZATION , *MECHANICAL engineering - Abstract
To find out knowledge about a design that has disappeared, become outdated, or been concealed, reverse engineering is required. Techniques have advanced from manual measurements to making use of 3D scanning technologies. In order to ascertain the benefits and drawbacks of techniques and technologies that use 3D scanning for reverse engineering, this study conducts a literature review. In the branch of the mechanical engineering design and manufacturing-based sectors, reverse engineering is essential. This method's importance to the process of product design is generally acknowledged. In a typical computerized manufacturing setting, the machine activity that turns the raw materials into the finished product is typically last, while the product design frequently comes first. When original drawings or documentation are unavailable, it is frequently necessary to reconstruct a CAD model of the current part using any digitalization techniques. This model is then analyzed and modified in order to create a better product design. Characterizing geometric models and associated surface representations, data segmenting and proper surface fitting fundaments a crucial task in reverse engineering are all crucial tasks in the reverse engineering process. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
38. Automation of non-destructive quality control by acoustic emission method of transport systems in mechanical engineering.
- Author
-
Azanov, Dmitry, Dityatev, Dmitry, Svirelkin, Sergey, Tuchkin, Igor, Saaya, Sai-Suu, Zagidullin, Ramil, and Khafizov, Ildar
- Subjects
- *
ACOUSTIC emission , *MECHANICAL engineering , *EMISSION control , *USB technology , *COMPACT groups , *QUALITY control - Abstract
The article describes methods for constructing acoustic emission systems for new devices with a USB interface. Using the example of the measurement modules of the RANIS system (manufacturer-ForTechLab LLC, www.e-mission.ru) it is shown how modern means of wireless communication can be used to build multi-level systems with a distributed measurement system. The prospects of using wireless acoustic emission systems are presented. For synchronous operation of all boards in the system, each of the boards has a synchronizing input and output. The synchronization of the RANIS system boards is possible by both wired and wireless methods. With the wired connection method, the boards are connected to each other along a chain, allowing you to build an extended distributed acoustic emission control system. Cross-board synchronization is performed when it is necessary to deploy a signal registration grid consisting of more than 4 sensors. Partial synchronization within compact sensor groups is possible if there is no synchronization between groups, which provides additional flexibility to the measurement system. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
39. Analysis of heating element modernization options for vacuum furnace.
- Author
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Medyakov, Andrey, Ostashenkov, Alexey, Konovalova, Olga, and Svechnikov, Vladimir
- Subjects
- *
FURNACES , *MECHANICAL engineering , *ELECTRIC insulators & insulation , *SHIPBUILDING , *THERMAL insulation , *HEATING , *ASTRONAUTICS - Abstract
The modern development of science and technology in fundamental industries such as nuclear, aviation, cosmonautics, shipbuilding, defense, mechanical engineering, as well as research in these areas require the creation of materials capable of operating in vacuum and in neutral gases at temperatures up to 2500 ° C and in rarefied medium up to 10−7 Pa. The increase in reliability is determined primarily by the materials and design parameters of the heating blocks, which include heaters, thermal insulation, electrical insulation and related elements. An important component of design optimization is the modeling of furnace operation features. In this regard, the problem of selecting and optimizing the design of the heating element of a vacuum furnace for high-temperature conditions is relevant. The task of the study is to analyze the possibilities of replacing a molybdenum heating element with an analog from other high-temperature alloys. As part of the study an analysis was made of the properties of a molybdenum heating element, as well as the properties of heaters made from other high-temperature alloys. The most optimal options for replacing the material of the heating element are proposed. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
40. Evaluation of the economic efficiency of the use of aggregate equipment in mechanical engineering.
- Author
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Leonov, Oleg, Temasova, Galina, Shkaruba, Nina, Vergazova, Yulia, and Bogolyubova, Daria
- Subjects
- *
ECONOMIC efficiency , *ENGINEERING equipment , *MECHANICAL engineering , *COMPARATIVE method , *PRODUCTION quantity - Abstract
The article discusses the issues of assessing the economic efficiency of one of the main directions of the development of modern technologies based on unification and being its logical conclusion – aggregation. The evaluation of the economic efficiency of the use of aggregate equipment at machine-building enterprises is carried out by a comparative method. The methodology for evaluating the efficiency of using aggregate equipment takes into account the costs before and after aggregation. The main efficiency is created in the field of operation of aggregate equipment. The sources of economic efficiency in aggregation are reducing the complexity of manufacturing products, creating conditions for increasing the annual volume of production by the same forces and on the same areas. The use of aggregate equipment allows to reduce the consumption of materials per unit of production, creates conditions for reducing the costs of its operation and repair. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
41. Preface: International Conference on Innovation in Mechanical and Civil Engineering (i-MACE 2022).
- Subjects
- *
CIVIL engineers , *CIVIL engineering , *MECHANICAL engineering , *CONFERENCES & conventions , *STRUCTURAL engineering - Abstract
This document is a preface to the International Conference on Innovation in Mechanical and Civil Engineering (i-MACE 2022). The conference, held in Pune, India, brought together experts from academic, scientific, and industrial communities to discuss new challenges and innovative ideas in the field of mechanical and civil engineering. The conference covered a wide range of topics, including modelling, simulation, optimization techniques, materials science, alternative energy, advanced manufacturing, design engineering, and more. The document also includes a list of advisory board members and organizing committee members involved in the conference. [Extracted from the article]
- Published
- 2024
- Full Text
- View/download PDF
42. Stationary non-axisymmetric deformation of a three-layer viscoelastic cylindrical shell under normal loading.
- Author
-
Safarov, I. I., Teshaev, M. Kh., Boltaev, Z. I., Ruziev, T. R., and Jalolov, F. B.
- Subjects
- *
CYLINDRICAL shells , *FOURIER integrals , *FOURIER series , *LIVE loads , *MECHANICAL engineering , *STRUCTURAL shells - Abstract
Circular cylindrical shells, as structural elements, have found wide application in various fields of mechanical engineering. The aim of this work is to study the action of a non-axisymmetric moving wave of normal pressure on a cylindrical shell interacting with an ideal compressible fluid. The problem of stationary non-axisymmetric deformation of a three-layer viscoelastic cylindrical shell under normal loading is considered. The relation between the stresses and strains satisfies the hereditary Boltzmann-Volterra relation. The response of an infinitely long three-layer cylindrical shell to the action of a non-axisymmetric normal load moving along the axis with a constant to resonant velocity is investigated in a refined formulation. The solution methods are based on the combined application of the Fourier integral transformation along the grid coordinate and the decomposition of all the given and unknown quantities into a Fourier series along the angular coordinate. An efficient algorithm for joint computation of integrals and Fourier series has been developed and implemented. For dissipative inhomogeneous mechanical systems the nonmonotonicity of the intensity of dissipation of energy of the mechanical system as a whole was found. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
43. A novel method for estimation of electrode kinetics parameters
- Author
-
Wang, Yongjing and Liu, Yingwei
- Published
- 2024
- Full Text
- View/download PDF
44. An improved protection of alanine for atmospheric corrosion of mild steel using carbon dots-montmorillonite hybrid materials
- Author
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Ma, Liang, Wang, Qiang, Yang, Haini, Zhang, Da Quan, and Wu, Wei
- Published
- 2024
- Full Text
- View/download PDF
45. Study of the role of aluminium and corrosion mechanism in galvalume coating in the marine atmospheric environment
- Author
-
Wang, Shuliu, Liu, Qianqian, Wang, Jin, Chen, Nana, Chen, JunHang, Song, Jialiang, Zhang, Xin, and Xiao, Kui
- Published
- 2024
- Full Text
- View/download PDF
46. Research of antiaging behavior of a new sealing coating for color painting cultural relics
- Author
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Li, Chao, Gao, Jin, Xu, Qingqing, Yang, Xuemei, Xiao, Kui, and Han, Xiangna
- Published
- 2024
- Full Text
- View/download PDF
47. Effect of hydrogen on the pitting corrosion behavior of Incoloy 825
- Author
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Li, Dongyang, Yao, Guanghu, Guan, Yuyuan, Han, Yaolei, Zhao, Linya, Xu, Lining, and Qiao, Lijie
- Published
- 2024
- Full Text
- View/download PDF
48. Effect of Ti and C addition on oxidation resistance of FeCoCrNiMn high entropy alloys prepared by powder metallurgy
- Author
-
Wang, Haichao, Liu, Xiaoqiang, Li, Zhanjiang, Chen, Li, Dai, Pinqiang, and Tang, Qunhua
- Published
- 2024
- Full Text
- View/download PDF
49. Effect of nano-Al2O3 particle addition on Co–P–xAl2O3 nanocomposite plating electroplated on X65 steel
- Author
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Liang, Guangwei, Gao, Zhiming, Deng, Cheng-Man, and Hu, Wenbin
- Published
- 2024
- Full Text
- View/download PDF
50. Synergistic effect of oxide nanoparticles and inorganic inhibitor on anti-corrosion performance of epoxy coating
- Author
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Nguyen, Thien Vuong, Do Truc, Vy, Nguyen, Tuan Anh, and Tran, Dai Lam
- Published
- 2024
- Full Text
- View/download PDF
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