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Engineering Science and Materials Commons™
Open Access. Powered by Scholars. Published by Universities.®
- Discipline
- Keyword
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- 3D printing (2)
- Additive manufacturing (2)
- Lacy cover (2)
- Laser peening (2)
- Passivation (2)
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- Peridynamics (2)
- Pitting corrosion (2)
- Salt layer (2)
- Site-specific; melt pool size; closed-loop control; additive manufacturing; directed energy deposition; 3D printing; metal; titanium; lasers (2)
- Stainless steel (2)
- 3D bioprinting (1)
- 3D bioprinting & Hybrid scaffold & Coating & Growth factor cocktail & Tissue engineering (1)
- 9R phase (1)
- Additive Manufacturing (1)
- Amorphous silicon oxycarbide (1)
- Annealing twin (1)
- Aortic arch (1)
- Aortic coarctation (1)
- Aqueous solution (1)
- Atomic force microscopy (1)
- Bending resistance (1)
- Biofilms (1)
- Bionanotechnology (1)
- Calcified plaque (1)
- Coating (1)
- Composite (1)
- Computational fluid dynamics (CFD) (1)
- Concrete; silica fume; mechanical properties; dynamic behaviors; impact loading; split Hopkinson pressure bar test (1)
- Covered stent (1)
- Crescent (1)
Articles 1 - 30 of 60
Full-Text Articles in Engineering Science and Materials
Generalized Ultrasonic Scattering Model For Arbitrary Transducer Configurations, Andrea P. Arguelles, Joseph A. Turner
Generalized Ultrasonic Scattering Model For Arbitrary Transducer Configurations, Andrea P. Arguelles, Joseph A. Turner
Department of Mechanical and Materials Engineering: Faculty Publications
Ultrasonic scattering in polycrystalline media is directly tied to microstructural features. As a result, modeling efforts of scattering from microstructure have been abundant. The inclusion of beam modeling for the ultrasonic transducers greatly simplified the ability to perform quantitative, fully calibrated experiments. In this article, a theoretical scattering model is generalized to allow for arbitrary source and receiver configurations, while accounting for beam behavior through the total propagation path. This extension elucidates the importance and potential of out-of-plane scattering modes in the context of microstructure characterization. The scattering coefficient is explicitly written for the case of statistical isotropy and ellipsoidal …
Generalized Ultrasonic Scattering Model For Arbitrary Transducer Configurations, Andrea P. Arguelles, Joseph A. Turner
Generalized Ultrasonic Scattering Model For Arbitrary Transducer Configurations, Andrea P. Arguelles, Joseph A. Turner
Department of Mechanical and Materials Engineering: Faculty Publications
Ultrasonic scattering in polycrystalline media is directly tied to microstructural features. As a result, modeling efforts of scattering from microstructure have been abundant. The inclusion of beam modeling for the ultrasonic transducers greatly simplified the ability to perform quantitative, fully calibrated experiments. In this article, a theoretical scattering model is generalized to allow for arbitrary source and receiver configurations, while accounting for beam behavior through the total propagation path. This extension elucidates the importance and potential of out-of-plane scattering modes in the context of microstructure characterization. The scattering coefficient is explicitly written for the case of statistical isotropy and ellipsoidal …
Multi-Scale Modeling Of The Lamellar Unit Of Arterial Media, Hozhabr Mozafari, Lulu Wang, Yuguo Lei, Linxia Gu
Multi-Scale Modeling Of The Lamellar Unit Of Arterial Media, Hozhabr Mozafari, Lulu Wang, Yuguo Lei, Linxia Gu
Department of Mechanical and Materials Engineering: Faculty Publications
The heterogeneity of the lamellar unit (LU) of arterial media plays an important role in the biomechanics of artery. Current two-component (fibrous component and a homogenous matrix) constitutive model is inappropriate for capturing the micro-structural variations in the LU, such as contraction/relaxation of vascular smooth muscle cells (VSMCs), fragmentation of the elastin layer, and deposition/disruption of the collagen network. In this work, we developed a representative volume element (RVE) model with detailed micro-configurations, i.e., VSMCs at various phenotypes, collagen fibers, and elastin laminate embedded in the ground substance. The fiber architecture was generated based on its volume fraction and orientations. …
Beyond The Toolpath: Site-Specific Melt Pool Size Control Enables Printing Of Extra-Toolpath Geometry In Laserwire-Based Directed Energy Deposition, Brian T. Gibson, Bradley S. Richardson, Tayler W. Undermann, Lonnie J. Love
Beyond The Toolpath: Site-Specific Melt Pool Size Control Enables Printing Of Extra-Toolpath Geometry In Laserwire-Based Directed Energy Deposition, Brian T. Gibson, Bradley S. Richardson, Tayler W. Undermann, Lonnie J. Love
Department of Mechanical and Materials Engineering: Faculty Publications
A variety of techniques have been utilized in metal additive manufacturing (AM) for melt pool size management, including modeling and feed-forward approaches. In a few cases, closed-loop control has been demonstrated. In this research, closed-loop melt pool size control for large-scale, laser wire-based directed energy deposition is demonstrated with a novel modification, i.e., site-specific changes to the controller setpoint were commanded at trigger points, the locations of which were generated by the projection of a secondary geometry onto the primary three-dimensional (3D) printed component geometry. The present work shows that, through this technique, it is possible to print a specific …
Effect Of Silica Fume In Concrete On Mechanical Properties And Dynamic Behaviors Under Impact Loading, Shijun Zhao, Qing Zhang
Effect Of Silica Fume In Concrete On Mechanical Properties And Dynamic Behaviors Under Impact Loading, Shijun Zhao, Qing Zhang
Department of Mechanical and Materials Engineering: Faculty Publications
The effect of silica fume (SF) in concrete on mechanical properties and dynamic behaviors was experimentally studied by split Hopkinson pressure bar (SHPB) device with pulse shaping technique. Three series of concrete with 0, 12%, and 16% SF as a cement replacement by weight were produced firstly. Then the experimental procedure for dynamic tests of concrete specimens with SF under a high loading rate was presented. Considering the mechanical performance and behaviors of the concrete mixtures, those tests were conducted under five different impact velocities. The experimental results clearly show concrete with different levels of SF is a strain-rate sensitive …
System And Method For Sensing Wind Flow Passing Over Complex Terrain, Saleh Nabi, Piyush Grover, Mithu Debnath
System And Method For Sensing Wind Flow Passing Over Complex Terrain, Saleh Nabi, Piyush Grover, Mithu Debnath
Department of Mechanical and Materials Engineering: Faculty Publications
A wind flow sensing system determines a first approximation of the velocity field at each of the altitudes by simulating computational fluid dynamics ( CFD ) of the wind flow with operating parameters reducing a cost function of a weighted combination of errors , determines a horizontal derivative of vertical velocity at each of the altitudes from the first approximation of the velocity fields , and determines a second approximation of the velocity fields using geometric relationships between a velocity field for each of the altitudes , projections of the measurements of radial velocities on the three - dimensional axes …
Multi-Agent Control System And Method, Piyush Grover, Karthik Elamvazhuthi
Multi-Agent Control System And Method, Piyush Grover, Karthik Elamvazhuthi
Department of Mechanical and Materials Engineering: Faculty Publications
Motion of multiple agents with identical non - linear dynamics is controlled to change density of the agents from the initial to the final density . A first control problem is formulated for optimizing a control cost of changing density of the agents from the initial density to the final density subject to dynamics of the agents in a density space . The first control problem , which is a non - linear non - convex problem over a multi - agent control and a density of the agents , is trans formed into a second control problem over the …
3d Printing Of Silk Fibroin-Based Hybrid Scaffold Treated With Platelet Rich Plasma For Bone Tissue Engineering, Liang Wei, Shaohua Wu, Mitchell Kuss, Xiping Jiang, Runjun Sun, Reid Patrick, Xiaohong Qin, Bin Duan
3d Printing Of Silk Fibroin-Based Hybrid Scaffold Treated With Platelet Rich Plasma For Bone Tissue Engineering, Liang Wei, Shaohua Wu, Mitchell Kuss, Xiping Jiang, Runjun Sun, Reid Patrick, Xiaohong Qin, Bin Duan
Department of Mechanical and Materials Engineering: Faculty Publications
3D printing/bioprinting are promising techniques to fabricate scaffolds with well controlled and patient-specific structures and architectures for bone tissue engineering. In this study, we developed a composite bioink consisting of silk fibroin (SF), gelatin (GEL), hyaluronic acid (HA), and tricalcium phosphate (TCP) and 3D bioprinted the silk fibroin-based hybrid scaffolds. The 3D bioprinted scaffolds with dual crosslinking were further treated with human platelet-rich plasma (PRP) to generate PRP coated scaffolds. Live/Dead and MTT assays demonstrated that PRP treatment could obviously promote the cell growth and proliferation of human adipose derived mesenchymal stem cells (HADMSC). In addition, the treatment of PRP …
3d Printing Of Silk Fibroin-Based Hybrid Scaffold Treated With Platelet Rich Plasma For Bone Tissue Engineering, Liang Wei, Shaohua Wu, Mitchell Kuss, Xiping Jiang, Runjun Sun, Reid Patrick, Xiaohong Qin, Bin Duan
3d Printing Of Silk Fibroin-Based Hybrid Scaffold Treated With Platelet Rich Plasma For Bone Tissue Engineering, Liang Wei, Shaohua Wu, Mitchell Kuss, Xiping Jiang, Runjun Sun, Reid Patrick, Xiaohong Qin, Bin Duan
Department of Mechanical and Materials Engineering: Faculty Publications
3D printing/bioprinting are promising techniques to fabricate scaffolds with well controlled and patient-specific structures and architectures for bone tissue engineering. In this study, we developed a composite bioink consisting of silk fibroin (SF), gelatin (GEL), hyaluronic acid (HA), and tricalcium phosphate (TCP) and 3D bioprinted the silk fibroin-based hybrid scaffolds. The 3D bioprinted scaffolds with dual crosslinking were further treated with human platelet-rich plasma (PRP) to generate PRP coated scaffolds. Live/Dead and MTT assays demonstrated that PRP treatment could obviously promote the cell growth and proliferation of human adipose derived mesenchymal stem cells (HADMSC). In addition, the treatment of PRP …
Experimental Evaluation Of Self-Expandable Metallic Tracheobronchial Stents, Yanli Wang, Pengfei Dong, Jingyao Ke, Xiang Shen, Zongming Li, Kewei Ren, Xinwei Han, Linxia Gu
Experimental Evaluation Of Self-Expandable Metallic Tracheobronchial Stents, Yanli Wang, Pengfei Dong, Jingyao Ke, Xiang Shen, Zongming Li, Kewei Ren, Xinwei Han, Linxia Gu
Department of Mechanical and Materials Engineering: Faculty Publications
The self-expandable metallic stents have been widely used in tracheobronchial obstruction or fistulation, including the J-shaped and Y-shaped stents, named after the shape of the branch-stem junction of the stent. However, there is scarce data on the mechanical performance of these tracheobronchial stents, which is essential for optimal stent implantation. In this work, eight self-expandable metallic tracheobronchial stents in three types (i.e., straight, J-shaped, and Y-shaped), with or without cover, were characterized. The compression resistance of the stems was investigated through both compression and indentation tests. The bending resistance of the branches in the J-shaped and Y-shaped stents was assessed …
Interface Effects On He Ion Irradiation In Nanostructured Materials, Wenfan Yang, Jingyu Pang, Shijian Zheng, Jian Wang, Xinghang Zhang, Xiuliang Ma
Interface Effects On He Ion Irradiation In Nanostructured Materials, Wenfan Yang, Jingyu Pang, Shijian Zheng, Jian Wang, Xinghang Zhang, Xiuliang Ma
Department of Mechanical and Materials Engineering: Faculty Publications
In advanced fission and fusion reactors, structural materials suffer from high dose irradiation by energetic particles and are subject to severe microstructure damage. He atoms, as a byproduct of the (n) transmutation reaction, could accumulate to form deleterious cavities, which accelerate radiation-induced embrittlement, swelling and surface deterioration, ultimately degrade the service lifetime of reactor materials. Extensive studies have been performed to explore the strategies that can mitigate He ion irradiation damage. Recently, nanostructured materials have received broad attention because they contain abundant interfaces that are efficient sinks for radiation-induced defects. In this review, we summarize and analyze the current understandings …
The Linc Complex, Mechanotransduction, And Mesenchymal Stem Cell Function And Fate, Tasneem Bouzid, Eunju Kim, Brandon D. Riehl, Amir Monemian Esfahani, Jordan Rosebohm, Ruiguo Yang, Bin Duan, Jung Yul Lim
The Linc Complex, Mechanotransduction, And Mesenchymal Stem Cell Function And Fate, Tasneem Bouzid, Eunju Kim, Brandon D. Riehl, Amir Monemian Esfahani, Jordan Rosebohm, Ruiguo Yang, Bin Duan, Jung Yul Lim
Department of Mechanical and Materials Engineering: Faculty Publications
Mesenchymal stem cells (MSCs) show tremendous promise as a cell source for tissue engineering and regenerative medicine, and are understood to be mechanosensitive to external mechanical environments. In recent years, increasing evidence points to nuclear envelope proteins as a key player in sensing and relaying mechanical signals in MSCs to modulate cellular form, function, and differentiation. Of particular interest is the Linker of Nucleoskeleton and Cytoskeleton (LINC) complex that includes nesprin and SUN. In this review, the way in which cells can sense external mechanical environments through an intact nuclear envelope and LINC complex proteins will be briefly described. Then, …
On The Measurement Of Energy Dissipation Of Adhered Cells With The Quartz Microbalance With Dissipation Monitoring, Amir Monemian Esfahani, Weiwei Zhao, Jennifer Y. Chen, Changjin Huang, Ning Xi, Jun Xi, Ruiguo Yang
On The Measurement Of Energy Dissipation Of Adhered Cells With The Quartz Microbalance With Dissipation Monitoring, Amir Monemian Esfahani, Weiwei Zhao, Jennifer Y. Chen, Changjin Huang, Ning Xi, Jun Xi, Ruiguo Yang
Department of Mechanical and Materials Engineering: Faculty Publications
We previously reported the finding of a linear correlation between the change of energy dissipation (ΔD) of adhered cells measured with the quartz crystal microbalance with dissipation monitoring (QCM-D) and the level of focal adhesions of the cells. To account for this correlation, we have developed a theoretical framework for assessing the ΔD-response of adhered cells. We rationalized that the mechanical energy of an oscillating QCM-D sensor coupled with a cell monolayer is dissipated through three main processes: the interfacial friction through the dynamic restructuring (formation and rupture) of cell-extracellular matrix (ECM) bonds, the interfacial viscous damping by the liquid …
Observations Of Shear Stress Effects On Staphylococcus Aureus Biofilm Formation, Erica Sherman, Kenneth W. Bayles, Derek Moormeir, Jennifer Endres, Timothy Wei
Observations Of Shear Stress Effects On Staphylococcus Aureus Biofilm Formation, Erica Sherman, Kenneth W. Bayles, Derek Moormeir, Jennifer Endres, Timothy Wei
Department of Mechanical and Materials Engineering: Faculty Publications
Staphylococcus aureus bacteria form biofilms and distinctive microcolony or “tower” structures that facilitate their ability to tolerate antibiotic treatment and to spread within the human body. The formation of microcolonies, which break off, get carried downstream, and serve to initiate biofilms in other parts of the body, is of particular interest here. It is known that flow conditions play a role in the development, dispersion, and propagation of biofilms in general. The influence of flow on microcolony formation and, ultimately, what factors lead to microcolony development are, however, not well understood. The hypothesis being examined is that microcolony structures form …
Modeling Thermal And Mechanical Cancellation Of Residual Stress From Hybrid Additive Manufacturing By Laser Peening, Guru Madireddy, Chao Li, Jingfu Liu, Michael P. Sealy
Modeling Thermal And Mechanical Cancellation Of Residual Stress From Hybrid Additive Manufacturing By Laser Peening, Guru Madireddy, Chao Li, Jingfu Liu, Michael P. Sealy
Department of Mechanical and Materials Engineering: Faculty Publications
Additive manufacturing (AM) of metals often results in parts with unfavorable mechanical properties. Laser peening (LP) is a high strain rate mechanical surface treatment that hammers a workpiece and induces favorable mechanical properties. Peening strain hardens a surface and imparts compressive residual stresses improving the mechanical properties of a material. This work investigates the role of LP on layer-by-layer processing of 3D printed metals using finite element analysis. The objective is to understand temporal and spatial residual stress development after thermal and mechanical cancellation caused by cyclically coupling printing and peening. Results indicate layer peening frequency is a critical process …
Method For Fabrication Of A Soft-Matter Printed Circuit Board, Carmel Majidi, Tong Lu, Eric J. Markvicka
Method For Fabrication Of A Soft-Matter Printed Circuit Board, Carmel Majidi, Tong Lu, Eric J. Markvicka
Department of Mechanical and Materials Engineering: Faculty Publications
A fabrication process for soft - matter printed circuit boards is disclosed in which traces of liquid - phase Ga - In eutectic ( eGaIn ) are patterned with UV laser micromachining ( UVLM ) . The terminals of the elastomer - sealed LM circuit connect to the surface mounted chips through vertically aligned columns of eGaIn - coated ferromagnetic micro spheres that are embedded within an interfacial elastomer layer .
Wearable Devices For Single-Cell Sensing And Transfection, Lingqian Chang, Yu-Chieh Wang, Faheem Ershad, Ruiguo Yang, Cunjiang Yu, Yubo Fan
Wearable Devices For Single-Cell Sensing And Transfection, Lingqian Chang, Yu-Chieh Wang, Faheem Ershad, Ruiguo Yang, Cunjiang Yu, Yubo Fan
Department of Mechanical and Materials Engineering: Faculty Publications
Wearable healthcare devices are mainly used for biosensing and transdermal delivery. Recent advances in wearable biosensors allow for long-term and real-time monitoring of physiological conditions at a cellular resolution. Transdermal drug delivery systems have been further scaled down, enabling wide selections of cargo, from natural molecules (e.g., insulin and glucose) to bioengineered molecules (e.g., nanoparticles). Some emerging nanopatches show promise for precise single-cell gene transfection in vivo and have advantages over conventional tools in terms of delivery efficiency, safety, and controllability of delivered dose. In this review, we discuss recent technical advances in wearable micro/nano devices with unique capabilities or …
Influence Of Metal Additives On Microstructure And Properties Of Amorphous Metal–Sioc Composites, Kaisheng Ming, Qing Su, Chao Gu, Dongyue Xie, Yongqiang Wang, Michael Nastasi, Jian Wang
Influence Of Metal Additives On Microstructure And Properties Of Amorphous Metal–Sioc Composites, Kaisheng Ming, Qing Su, Chao Gu, Dongyue Xie, Yongqiang Wang, Michael Nastasi, Jian Wang
Department of Mechanical and Materials Engineering: Faculty Publications
Strong, ductile, and irradiation-tolerant structural materials are in urgent demand for improving the safety and efficiency of advanced nuclear reactors. Amorphous ceramics could be promising candidates for high irradiation tolerance due to thermal stability and lack of crystal defects. However, they are very brittle due to plastic flow instability. Here, we realized enhanced plasticity of amorphous ceramics through compositional and microstructural engineering. Two metal–amorphous ceramic composites, Fe-SiOC and Cu-SiOC, were fabricated by magnetron sputtering. Iron atoms are preferred to form uniformly distributed nano-sized Fe-rich amorphous clusters, while copper atoms grow non-uniformly distributed nano-crystalline Cu particles. The Fe-SiOC composite exhibits high …
Biomechanical Foot Guidance Linkage, Carl Nelson, Cale J. Stolle, Judith M. Burnfield
Biomechanical Foot Guidance Linkage, Carl Nelson, Cale J. Stolle, Judith M. Burnfield
Department of Mechanical and Materials Engineering: Faculty Publications
A gait replication apparatus can include a scalable mechanical mechanism configured to replicate different gaits . The scalable mechanical mechanism can include , for example , a four - bar linkage , a pantograph , a cam / Scotch - yoke mechanism , and so forth . In some embodiments , the mechanical mechanism includes a beam rotating about an axis passing proximate to its center , with a foot pedal slidably coupled with the beam , and a timing chain / belt or cable pulley - pair coupled with the foot pedal and looped about the beam . A …
Soft , Multilayered Electronics For Wearable Devices And Methods To Produce The Same, Carmel Majidi, Michael D. Bartlett, Eric J. Markvicka
Soft , Multilayered Electronics For Wearable Devices And Methods To Produce The Same, Carmel Majidi, Michael D. Bartlett, Eric J. Markvicka
Department of Mechanical and Materials Engineering: Faculty Publications
Disclosed herein is an efficient fabrication approach to create highly customizable wearable electronics through rapid laser machining and adhesion - controlled soft materials assembly . Well - aligned , multi - layered materials can be created from 2D and 3D elements that stretch and bend while seamlessly integrating with rigid components such as micro chip integrated circuits ( IC ) , discrete electrical components , and interconnects . These techniques are applied using commercially available materials . These materials and methods enable custom wearable electronics while offering versatility in design and functionality for a variety of bio - monitor ing …
Gastrointestinal Sensor Implantation System, Benjamin Terry, Weston Lewis, Wanchuan Xie, Pengbo Li, Alfred Tsubaki
Gastrointestinal Sensor Implantation System, Benjamin Terry, Weston Lewis, Wanchuan Xie, Pengbo Li, Alfred Tsubaki
Department of Mechanical and Materials Engineering: Faculty Publications
A gastrointestinal ( GI ) sensor deployment device is dis closed . In implementations , the sensor deployment device includes an orally - administrable capsule with a tissue cap ture device removably coupled to the orally - administrable capsule . The tissue capture device includes a plurality of fasteners for connecting the tissue capture device to GI tissue within a body . A biometric sensor is coupled to the tissue capture device for continuous or periodic monitoring of the GI tract of the body at the GI tissue attachment location . A chamber within the orally - administrable capsule is …
Interactions Between Dislocations And Three-Dimensional Annealing Twins In Face Centered Cubic Metals, Yanxiang Liang, Xiaofang Yang, Mingyu Gong, Guisen Liu, Qing Liu, Jian Wang
Interactions Between Dislocations And Three-Dimensional Annealing Twins In Face Centered Cubic Metals, Yanxiang Liang, Xiaofang Yang, Mingyu Gong, Guisen Liu, Qing Liu, Jian Wang
Department of Mechanical and Materials Engineering: Faculty Publications
Annealing twins often form in metals with a face centered cubic structure during thermal and mechanical processing. Here, we conducted molecular dynamic (MD) simulations for copper and aluminum to study the interaction processes between {1 1 1}1/2 <1 1 0> dislocations and a three-dimensional annealing twin. Twin boundaries are characterized with Σ3{1 1 1} coherent twin boundaries (CTBs) and Σ3{1 1 2} incoherent twin boundaries (ITBs). MD results revealed that dislocation-ITB interactions affect slip transmission for a dislocation crossing CTBs, facilitating the nucleation of Lomer dislocation.
Deep Learning Segmentation Of Coronary Calcified Plaque From Intravascular Optical Coherence Tomography (Ivoct) Images With Application To Finite Element Modeling Of Stent Deployment, Yazan Gharaibeh, Pengfei Dong, David Prabhu, Chaitanya Kolluru, Juhwan Lee, Vlad Zimin, Hozhabr Mozafari, Hiram Bizzera, Linxia Gu, David Wilson
Deep Learning Segmentation Of Coronary Calcified Plaque From Intravascular Optical Coherence Tomography (Ivoct) Images With Application To Finite Element Modeling Of Stent Deployment, Yazan Gharaibeh, Pengfei Dong, David Prabhu, Chaitanya Kolluru, Juhwan Lee, Vlad Zimin, Hozhabr Mozafari, Hiram Bizzera, Linxia Gu, David Wilson
Department of Mechanical and Materials Engineering: Faculty Publications
Because coronary artery calcified plaques can hinder or eliminate stent deployment, interventional cardiologists need a better way to plan interventions, which might include one of the many methods for calcification modification (e.g., atherectomy). We are imaging calcifications with intravascular optical coherence tomography (IVOCT), which is the lone intravascular imaging technique with the ability to image the extent of a calcification, and using results to build vessel-specific finite element models for stent deployment. We applied methods to a large set of image data (>45 lesions and > 2,600 image frames) of calcified plaques, manually segmented by experts into calcified, lumen and …
Strength And Plasticity Of Amorphous Silicon Oxycarbide, Kaisheng Ming, Chao Gu, Qing Su, Yongqiang Wang, Arezoo Zare, Don A. Lucca, Michael Nastasi, Jian Wang
Strength And Plasticity Of Amorphous Silicon Oxycarbide, Kaisheng Ming, Chao Gu, Qing Su, Yongqiang Wang, Arezoo Zare, Don A. Lucca, Michael Nastasi, Jian Wang
Department of Mechanical and Materials Engineering: Faculty Publications
Amorphous SiOC films were synthesized by magnetron sputtering at room temperature with/without radio frequency (RF) bias and further improved in terms of mechanical properties by ion irradiation. As-deposited SiOC films without RF bias exhibit catastrophic failure at a low stress and strain, which is ascribed to microstructural heterogeneities associated with the formation of voids during deposition, as evidenced by transmission electron microscopy. Ion irradiation unifies microstructure accompanied with eliminating the voids, resulting in a simultaneously increase in strength and plasticity (ultimate strength of 5–7 GPa and the strain to shear instability of over 20%). Homogeneous microstructures are demonstrated to ensure …
Fast Growth Of Thin Mapbi3 Crystal Wafers On Aqueous Solution Surface For Efficient Lateral-Structure Perovskite Solar Cells, Ye Liu, Qingfeng Dong, Yanjun Fang, Yuze Lin, Yehao Deng, Jinsong Huang
Fast Growth Of Thin Mapbi3 Crystal Wafers On Aqueous Solution Surface For Efficient Lateral-Structure Perovskite Solar Cells, Ye Liu, Qingfeng Dong, Yanjun Fang, Yuze Lin, Yehao Deng, Jinsong Huang
Department of Mechanical and Materials Engineering: Faculty Publications
Solar-grade single or multiple crystalline wafers are needed in large quantities in the solar cell industry, and are generally formed by a top-down process from crystal ingots, which causes a significant waste of materials and energy during slicing, polishing, and other processing. Here, a bottom-up technique that allows the growth of wafer-size hybrid perovskite multiple crystals directly from aqueous solution is reported. Single-crystalline hybrid perovskite wafers with centimeter size are grown at the top surface of a perovskite precursor solution. As well as saving raw materials, this method provides unprecedented advantages such as easily tunable thickness and rapid growth of …
The Role Of Low-Level Image Features In The Affective Categorization Of Rapidly Presented Scenes, L. Jack Rhodes, Matthew Rios, Jacob M. Williams, Gonzalo Quinones, Prahalada K. Rao, Vladimir Miskovic
The Role Of Low-Level Image Features In The Affective Categorization Of Rapidly Presented Scenes, L. Jack Rhodes, Matthew Rios, Jacob M. Williams, Gonzalo Quinones, Prahalada K. Rao, Vladimir Miskovic
Department of Mechanical and Materials Engineering: Faculty Publications
It remains unclear how the visual system is able to extract affective content from complex scenes even with extremely brief (< 100 millisecond) exposures. One possibility, suggested by findings in machine vision, is that low-level features such as unlocalized, two-dimensional (2-D) Fourier spectra can be diagnostic of scene content. To determine whether Fourier image amplitude carries any information about the affective quality of scenes, we first validated the existence of image category differences through a support vector machine (SVM) model that was able to discriminate our intact aversive and neutral images with ~ 70% accuracy using amplitude-only features as inputs. This model allowed us to confirm that scenes belonging to different affective categories could be mathematically distinguished on the basis of amplitude spectra alone. The next question is whether these same features are also exploited by the human visual system. Subsequently, we tested observers’ rapid classification of affective and neutral naturalistic scenes, presented briefly (~33.3 ms) and backward masked with synthetic textures. We tested categorization accuracy across three distinct experimental conditions, using: (i) original images, (ii) images having their amplitude spectra swapped within a single affective image category (e.g., an aversive image whose amplitude spectrum has been swapped with another aversive image) or (iii) images having their amplitude spectra swapped between affective categories (e.g., an aversive image containing the amplitude spectrum of a neutral image). Despite its discriminative potential, the human visual system does not seem to use Fourier amplitude differences as the chief strategy for affectively categorizing scenes at a glance. The contribution of image amplitude to affective categorization is largely dependent on interactions with the phase spectrum, although it is impossible to completely rule out a residual role for unlocalized 2-D amplitude measures.
Segregation Of Mo Atoms Into Stacking Faults In Crfeconimo Alloy, Kaisheng Ming, Xiaofang Bi, Jian Wang
Segregation Of Mo Atoms Into Stacking Faults In Crfeconimo Alloy, Kaisheng Ming, Xiaofang Bi, Jian Wang
Department of Mechanical and Materials Engineering: Faculty Publications
Solute segregation at dislocations can impede the motion of dislocations, strengthening materials. Here, we study the formation and role of solute segregation at dislocations in CrFeCoNiMo high-entropy alloys (HEAs) by high-angle annular dark-field scanning transmission electron microscopy imaging and mechanical testing both deformed and annealed samples. Mo atoms exhibit pronounced segregation into the planar-extended core of dislocations, i.e. stacking faults, causing the increase in the yield strength while the loss of the ductility. This work suggests that mechanical properties of HEAs can be tailored by alloying additional elements that are in favor of segregation into dislocations.
Disposable Fluidic Self-Propelling Robot For Traversing A Tubular Passage, Carl Nelson, Benjamin Terry, Abolfazl Pourghodrat, Hossein Dehghani, Dmitry Oleynikov, Prithviraj Dasgupta
Disposable Fluidic Self-Propelling Robot For Traversing A Tubular Passage, Carl Nelson, Benjamin Terry, Abolfazl Pourghodrat, Hossein Dehghani, Dmitry Oleynikov, Prithviraj Dasgupta
Department of Mechanical and Materials Engineering: Faculty Publications
A probe for traversing a tubular passage includes an introducer to be supported at an entrance to the tubular passage. The probe also includes a probe tip to traverse the tubular passage, and a tube with an inflatable tube segment. In some embodiments, the inflatable tube segment is storable in the probe tip. The inflatable tube segment is configured to be inflated to push the probe tip away from the introducer toward an end on the tubular passage. In some embodiments, the probe includes a sealing mechanism, whre the sealing mechanism can be positioned between the inflatable tube segment of …
Robotic Devicewith Compact Joint Design And Related Systems And Methods, Tom Frederick, Eric Markvicka, Shane Michael Farritor, Dmitry Oleynikov
Robotic Devicewith Compact Joint Design And Related Systems And Methods, Tom Frederick, Eric Markvicka, Shane Michael Farritor, Dmitry Oleynikov
Department of Mechanical and Materials Engineering: Faculty Publications
The embodiments disclosed herein relate to various robotic and/or in vivo medical devices having compact joint configurations. Other embodiments relate to various medical device components, including forearms having grasper or cautery end effectors, that can be incorporated into certain robotic and/or in vivo medical devices.
High Strength, Deformable Nanotwinned Al–Co Alloys, S. Xue, Qiang Li, D. Y. Xie, Y. F. Zhang, Han Wang, Haiyan Wong, J. Wang, Xinghang Zhang
High Strength, Deformable Nanotwinned Al–Co Alloys, S. Xue, Qiang Li, D. Y. Xie, Y. F. Zhang, Han Wang, Haiyan Wong, J. Wang, Xinghang Zhang
Department of Mechanical and Materials Engineering: Faculty Publications
Aluminum (Al) alloys have been widely used in the transportation industry. However, most highstrength Al alloys to date have limited mechanical strength, on the order of a few hundred MPa, which is much lower than the flow stress of high-strength steels. In this study, we show the fabrication of nanocrystalline Al alloys with high-density growth twins enabled by a few atomic percent of Co solute. In situ uniaxial compression tests show that the flow stress of Al–Co solid solution alloys exceeds 1.5 GPa, while good work hardening capability is maintained. This study provides a new perspective on the design of …