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Articles 91 - 120 of 566

Full-Text Articles in Other Engineering Science and Materials

Visualization And Validation Of Twin Nucleation And Early-Stage Growth In Magnesium, Lin Jiang, Mingyu Gong, Jian Wang, Zhiliang Pan, Xin Wang, Dalong Zhang, Y. Morris Wang, Jim Ciston, Andrew M. Minor, Mingjie Xu, Xiaoqing Pan, Timothy J. Rupert, Subhash Mahajan, Enrique J. Lavernia, Irene J. Beyerlein, Julie M. Schoenung Jan 2022

Visualization And Validation Of Twin Nucleation And Early-Stage Growth In Magnesium, Lin Jiang, Mingyu Gong, Jian Wang, Zhiliang Pan, Xin Wang, Dalong Zhang, Y. Morris Wang, Jim Ciston, Andrew M. Minor, Mingjie Xu, Xiaoqing Pan, Timothy J. Rupert, Subhash Mahajan, Enrique J. Lavernia, Irene J. Beyerlein, Julie M. Schoenung

Department of Mechanical and Materials Engineering: Faculty Publications

The abrupt occurrence of twinning when Mg is deformed leads to a highly anisotropic response, making it too unreliable for structural use and too unpredictable for observation. Here, we describe an in-situ transmission electron microscopy experiment on Mg crystals with strategically designed geometries for visualization of a long-proposed but unverified twinning mechanism. Combining with atomistic simulations and topological analysis, we conclude that twin nucleation occurs through a pure-shuffle mechanism that requires prismatic-basal transformations. Also, we verified a crystal geometry dependent twin growth mechanism, that is the early-stage growth associated with instability of plasticity flow, which can be dominated either by …

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Grinding And Super-Finishing Test Machine Project, Michael Simon Jan 2022

Grinding And Super-Finishing Test Machine Project, Michael Simon

Williams Honors College, Honors Research Projects

A research project in The University of Akron to study grinding and super-finishing of silicon nitride ceramic was initiated by Dr. Siamak Farhad and sponsored by the Timken Company, with the assistance of undergraduate students Michael Simon, Ryan Hosso and Mathew Rozmajzl. The study required analysis of forces and scratches generated during grinding processes of silicon nitride samples. A testing assembly was designed and constructed to record the forces generated during grinding and super-finishing of silicon nitride samples in a computer-numerical-control machine. Silicon nitride samples were subjected to desired grinding and super-finishing operations and all forces generated during the process …

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Type Iii And Iv Deformation Twins In Minerals And Metals, John P. Hirth, Greg Hirth, Jian Wang Jan 2022

Type Iii And Iv Deformation Twins In Minerals And Metals, John P. Hirth, Greg Hirth, Jian Wang

Department of Mechanical and Materials Engineering: Faculty Publications

Type IV twins are defined and shown to exist in triclinic crystal systems, as well as in some monoclinic and trigonal systems. Here, we focus on Pericline twins in triclinic plagioclase as an example. Type IV twins are associated with the irrationality of one of the twinning elements that is rational for a type II twin. The formation of type IV twins is accomplished through the shear on a K2 plane produced by the motion of twinning disconnections on a K1 plane, followed by rotational partitioning. The same systems where type IV twins are present also have type III twins …

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Emissivity Prediction Of Functionalized Surfaces Using Artificial Intelligence, Greg Acosta, Andrew Reicks, Miguel Moreno, Alireza Borjali, Craig Zuhlke, Mohammad Ghashami Jan 2022

Emissivity Prediction Of Functionalized Surfaces Using Artificial Intelligence, Greg Acosta, Andrew Reicks, Miguel Moreno, Alireza Borjali, Craig Zuhlke, Mohammad Ghashami

Department of Mechanical and Materials Engineering: Faculty Publications

Tuning surface emissivity has been of great interest in thermal radiation applications, such as thermophotovoltaics and passive radiative cooling. As a low-cost and scalable technique for manufacturing surfaces with desired emissivities, femtosecond laser surface processing (FLSP) has recently drawn enormous attention. Despite the versatility offered by FLSP, there is a knowledge gap in accurately predicting the outcome emissivity prior to fabrication. In this work, we demonstrate the immense advantage of employing artificial intelligence (AI) techniques to predict the emissivity of complex surfaces. For this aim, we used FLSP to fabricate 116 different aluminum samples. A comprehensive dataset was established by …

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Construction Of A Peridynamic Model For Viscous Flow, Jiangming Zhao, Adam Larios, Florin Bobaru Ph.D. Jan 2022

Construction Of A Peridynamic Model For Viscous Flow, Jiangming Zhao, Adam Larios, Florin Bobaru Ph.D.

Department of Mechanical and Materials Engineering: Faculty Publications

We derive the Eulerian formulation for a peridynamic (PD) model of Newtonian viscous flow starting from fundamental principles: conservation of mass and momentum. This formulation is different from models for viscous flow that utilize the so-called “peridynamic differential operator” with the classical Navier- Stokes equations. We show that the classical continuity equation is a limiting case of the PD one, assuming certain smoothness conditions. The PD model for viscous flow is calibrated to the classical Navier-Stokes equations by enforcing linear consistency for the viscous stress term. Couette and Poiseuille flows, and incompressible fluid flow past a regular lattice of cylinders …

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Ultrathin Coding Metasurface For Underwater Wave Focusing, Branching And Self-Bending Generation With One Single Actuator, Lixie Song, Zhong Chen, Mehrdad Negahban, Lei Liang, Zheng Li, Zheng Wu Jan 2022

Ultrathin Coding Metasurface For Underwater Wave Focusing, Branching And Self-Bending Generation With One Single Actuator, Lixie Song, Zhong Chen, Mehrdad Negahban, Lei Liang, Zheng Li, Zheng Wu

Department of Mechanical and Materials Engineering: Faculty Publications

A novel metasurface is proposed that aims to generate underwater acoustic waves with various functions by only one actuator. Each metasurface unit consists of an air cavity sandwiched on one side by a vibration plate and connecting rubber supports. By properly selecting the ratio of the plate to unit lengths, a phase shift of π can be attained to constitute a binary coding metasurface. Three demonstrations, including focusing, branching and self-bending waves, are chosen to validate the functionality of the design. The design is also shown to work over a wide frequency range through changing the ratio. In addition, the …

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Machine Learning Assisted Metamaterial‑Based Reconfigurable Antenna For Low‑Cost Portable Electronic Devices, Shobhit K. Patel, Jaymit Surve, Vijay Katkar, Juveriya Parmar Jan 2022

Machine Learning Assisted Metamaterial‑Based Reconfigurable Antenna For Low‑Cost Portable Electronic Devices, Shobhit K. Patel, Jaymit Surve, Vijay Katkar, Juveriya Parmar

Department of Mechanical and Materials Engineering: Faculty Publications

Antenna design has evolved from bulkier to small portable designs but there is a need for smarter antenna design using machine learning algorithms that can meet today’s high growing demand for smart and fast devices. Here in this research, main focus is on developing smart antenna design using machine learning applicable in 5G mobile applications and portable Wi-Fi, Wi-MAX, and WLAN applications. Our design is based on the metamaterial concept where the patch is truncated and etched with a split ring resonator (SRR). The high gain requirement is met by adding metamaterial superstrates having thin wires (TW) and SRRs. The …

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Symmetric Or Asymmetric Glide Resistance To Twinning Disconnection?, Mingyu Gong, Houyu Ma, Kunming Yang, Yue Liu, Jian-Feng Nie, Jian Wang Jan 2022

Symmetric Or Asymmetric Glide Resistance To Twinning Disconnection?, Mingyu Gong, Houyu Ma, Kunming Yang, Yue Liu, Jian-Feng Nie, Jian Wang

Department of Mechanical and Materials Engineering: Faculty Publications

Successive gliding of twinning disconnections (TDs) creates three-dimensional twins in parent crystal and accommodates shear deformation. It is generally recognized that TD is subject to the same Peierls stress as it glides forward or backward because of its dislocation character and the twofold rotation symmetry of the twin plane. Based on atomistic simulations, we demonstrate that the glide of TDs may be subject to a symmetric or asymmetric resistance corresponding to step character, symmetric resistance for A/A type steps but asymmetric resistance for A/B type steps, where A and B represent crystallographic planes in twin and matrix. Furthermore, we experimentally …

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Recent Advances In Biosensors For Detection Of Covid-19 And Other Viruses, Shobhit K. Patel, Jaymit Surve, Juveriya Parmar, Kawsar Ahmed, Francis M. Bui, Fahad Ahmed Al-Zahrani Jan 2022

Recent Advances In Biosensors For Detection Of Covid-19 And Other Viruses, Shobhit K. Patel, Jaymit Surve, Juveriya Parmar, Kawsar Ahmed, Francis M. Bui, Fahad Ahmed Al-Zahrani

Department of Mechanical and Materials Engineering: Faculty Publications

This century has introduced very deadly, dangerous, and infectious diseases to humankind such as the influenza virus, Ebola virus, Zika virus, and the most infectious SARS-CoV-2 commonly known as COVID-19 and have caused epidemics and pandemics across the globe. For some of these diseases, proper medications, and vaccinations are missing and the early detection of these viruses will be critical to saving the patients. And even the vaccines are available for COVID-19, the new variants of COVID-19 such as Delta, and Omicron are spreading at large. The available virus detection techniques take a long time, are costly, and complex and …

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A Robot-Assisted Acoustofluidic End Effector, Jan Durrer, Prajwal Agrawal, Ali Ozgul, Stephen C.F. Neuhauss, Nitesh Nama, Daniel Ahmed Jan 2022

A Robot-Assisted Acoustofluidic End Effector, Jan Durrer, Prajwal Agrawal, Ali Ozgul, Stephen C.F. Neuhauss, Nitesh Nama, Daniel Ahmed

Department of Mechanical and Materials Engineering: Faculty Publications

Liquid manipulation is the foundation of most laboratory processes. For macroscale liquid handling, both do-it-yourself and commercial robotic systems are available; however, for microscale, reagents are expensive and sample preparation is difficult. Over the last decade, lab-on-a-chip (LOC) systems have come to serve for microscale liquid manipulation; however, lacking automation andmulti-functionality. Despite their potential synergies, each has grown separately and no suitable interface yet exists to link macro-level robotics with micro-level LOC or microfluidic devices. Here, we present a robot-assisted acoustofluidic end effector (RAEE) system, comprising a robotic arm and an acoustofluidic end effector, that combines robotics and microfluidic functionalities.We …

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Smooth Muscle Cells Affect Differential Nanoparticle Accumulation In Disturbed Blood Flow-Induced Murine Atherosclerosis, Hunter Miller, Morgan A. Schake, Badrul Alam Bony, Evan T. Curtis, Conner C. Gee, Ian Mccue, Thomas J. Ripperda Jr., Yiannis S. Chatzizisis, Forrest Kievit, Ryan M. Pedrigi Dec 2021

Smooth Muscle Cells Affect Differential Nanoparticle Accumulation In Disturbed Blood Flow-Induced Murine Atherosclerosis, Hunter Miller, Morgan A. Schake, Badrul Alam Bony, Evan T. Curtis, Conner C. Gee, Ian Mccue, Thomas J. Ripperda Jr., Yiannis S. Chatzizisis, Forrest Kievit, Ryan M. Pedrigi

Department of Mechanical and Materials Engineering: Faculty Publications

Atherosclerosis is a lipid-driven chronic inflammatory disease that leads to the formation of plaques in the inner lining of arteries. Plaques form over a range of phenotypes, the most severe of which is vulnerable to rupture and causes most of the clinically significant events. In this study, we evaluated the efficacy of nanoparticles (NPs) to differentiate between two plaque phenotypes based on accumulation kinetics in a mouse model of atherosclerosis. This model uses a perivascular cuff to induce two regions of disturbed wall shear stress (WSS) on the inner lining of the instrumented artery, low (upstream) and multidirectional (downstream), which, …

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Microfabricated Platforms To Investigate Cell Mechanical Properties, Amir M. Esfahani, Grayson Minnick, Jordan Rosenbohm, Haiwei Zhai, Xiaowei Jin, Bahareh Tajvidi Safa, Justin Brooks, Ruiguo Yang Dec 2021

Microfabricated Platforms To Investigate Cell Mechanical Properties, Amir M. Esfahani, Grayson Minnick, Jordan Rosenbohm, Haiwei Zhai, Xiaowei Jin, Bahareh Tajvidi Safa, Justin Brooks, Ruiguo Yang

Department of Mechanical and Materials Engineering: Faculty Publications

Mechanical stimulation has been imposed on living cells using several approaches. Most early investigations were conducted on groups of cells, utilizing techniques such as substrate deformation and flow-induced shear. To investigate the properties of cells individually, many conventional techniques were utilized, such as AFM, optical traps/optical tweezers, magnetic beads, and micropipette aspiration. In specific mechanical interrogations, microelectro- mechanical systems (MEMS) have been designed to probe single cells in different interrogation modes. To exert loads on the cells, these devices often comprise piezo-electric driven actuators that attach directly to the cell or move a structure on which cells are attached. Uniaxial …

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Quick - Release End Effector Tool Interface, Shane Farritor, Thomas Frederick Nov 2021

Quick - Release End Effector Tool Interface, Shane Farritor, Thomas Frederick

Department of Mechanical and Materials Engineering: Faculty Publications

The various embodiments herein relate to a coupling apparatus for a medical device having a coupler body, a cavity defined in the coupler body, a rotatable drive component disposed within the cavity and having at least two pin receiving openings, and an actuable locking ring disposed around the cavity.

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In Situ Characterization Of Tensile Behavior Of Laser Rapid Solidified Al–Si Heterogeneous Microstructures, Bingqiang Wei, Wenqian Wu, Dongyue Xie, Huai-Hsun Lien, Metin Kayitmazbatir, Amit Misra, Jian Wang Oct 2021

In Situ Characterization Of Tensile Behavior Of Laser Rapid Solidified Al–Si Heterogeneous Microstructures, Bingqiang Wei, Wenqian Wu, Dongyue Xie, Huai-Hsun Lien, Metin Kayitmazbatir, Amit Misra, Jian Wang

Department of Mechanical and Materials Engineering: Faculty Publications

Heterogeneous Al–Si microstructure comprising of sub-micron-scale Al dendrites and nanoscale Al–Si fibrous eutectic was fabricated by processing as-cast Al-20wt.%Si alloy using laser rapid solidification. In situ tension tests explored high tensile strength ( ∼ 600 MPa) and ductility ( ∼ 10%) and high strain hardening rate ( ∼ 7 GPa). Microstructural characterization revealed the plastic co[1]deformation mechanisms between soft Al dendrites and hard nanoscale Al–Si eutectic. The progression of plasticity in nanoscale Al–Si eutectic with increasing applied strain is accommodated by dislocation plasticity in the nano-Al channels and cracking Si nanofibers. The propagation of nano-cracks is suppressed by surrounding Al, …

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Digitally Twinned Additive Manufacturing: Detecting Flaws In Laser Powder Bed Fusion By Combining Thermal Simulations With In-Situmeltpool Sensor Data, R Yavari, A Riensche, E Tekerek, L Jacquemetton, H Halliday, M Vandever, A Tenequer, V Perumal, A Kontsos, Z Smoqi, K Cole, P Rao Oct 2021

Digitally Twinned Additive Manufacturing: Detecting Flaws In Laser Powder Bed Fusion By Combining Thermal Simulations With In-Situmeltpool Sensor Data, R Yavari, A Riensche, E Tekerek, L Jacquemetton, H Halliday, M Vandever, A Tenequer, V Perumal, A Kontsos, Z Smoqi, K Cole, P Rao

Department of Mechanical and Materials Engineering: Faculty Publications

The goal of this research is the in-situ detection of flaw formation in metal parts made using the laser powder bed fusion (LPBF) additive manufacturing process. This is an important area of research, because, despite the considerable cost and time savings achieved, precision-driven industries, such as aerospace and biomedical, are reticent in using LPBF to make safety–critical parts due to tendency of the process to create flaws. Another emerging concern in LPBF, and additive manufacturing in general, is related to cyber security – malicious actors may tamper with the process or plant flaws inside a part to compromise its performance. …

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Contact Angle Measurement Using A Hele-Shaw Cell: A Proof-Of-Concept Study, Haipeng Zhang, Jacob Gottberg, Sangjin Ryu Aug 2021

Contact Angle Measurement Using A Hele-Shaw Cell: A Proof-Of-Concept Study, Haipeng Zhang, Jacob Gottberg, Sangjin Ryu

Department of Mechanical and Materials Engineering: Faculty Publications

Contact angle is an important property to quantify the wettability of a solid surface with a liquid, which characterizes interactions of the solid-liquid pair. Generally, to measure contact angle, special instruments such as a goniometer are necessary, but they are not readily available in certain research settings. In this study, an alternative method to measure contact angle based on a Hele-Shaw cell, microscopy imaging, and image processing is suggested. In this method, a liquid drop is injected into a transparent Hele-Shaw cell, the meniscus of the drop is captured in the top or bottom view using a brightfield microscope, and …

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Contact Angle Measurement Using A Hele-Shaw Cell: A Proof-Of-Concept Study, Haipeng Zhang, Jacob Gottberg, Sangjin Ryu Aug 2021

Contact Angle Measurement Using A Hele-Shaw Cell: A Proof-Of-Concept Study, Haipeng Zhang, Jacob Gottberg, Sangjin Ryu

Department of Mechanical and Materials Engineering: Faculty Publications

Contact angle is an important property to quantify the wettability of a solid surface with a liquid, which characterizes interactions of the solid-liquid pair. Generally, to measure contact angle, special instruments such as a goniometer are necessary, but they are not readily available in certain research settings. In this study, an alternative method to measure contact angle based on a Hele-Shaw cell, microscopy imaging, and image processing is suggested. In this method, a liquid drop is injected into a transparent Hele-Shaw cell, the meniscus of the drop is captured in the top or bottom view using a brightfield microscope, and …

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Methods , Systems , And Devices Relating To Surgical End Effectors, Shane M. Farritor, Thomas Frederick, Joe Bartels Jul 2021

Methods , Systems , And Devices Relating To Surgical End Effectors, Shane M. Farritor, Thomas Frederick, Joe Bartels

Department of Mechanical and Materials Engineering: Faculty Publications

The embodiments disclosed herein relate to various medical device components , including components that can be incorporated into robotic and / or in vivo medical devices, and more specifically including end effectors that can be incorporated into such devices. Certain end effector embodiments include various vessel cautery devices that have rotational movement as well as cautery and cutting functions while maintaining a relatively compact structure. Other end effector embodiments include various end effector devices that have more than one end effector.

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Robotic Surgical Devices , Systems , And Related Methods, Shane Farritor, Erik Mumm, Philip Chu, Nishant Kumar, Jason Dumpert, Yutaka Tsutano Jul 2021

Robotic Surgical Devices , Systems , And Related Methods, Shane Farritor, Erik Mumm, Philip Chu, Nishant Kumar, Jason Dumpert, Yutaka Tsutano

Department of Mechanical and Materials Engineering: Faculty Publications

The embodiments disclosed herein relate to various medical device components, including components that can be incorporated into robotic and / or in vivo medical devices. Certain embodiments include various modular medical devices for in vivo medical procedures.

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In Vivo Printing Of Growth Factor-Eluting Adhesive Scaffolds Improves Wound Healing, Kristo Nuutila, Mohamadmahdi Samandari, Yori Endo, Yuteng Zhang, Jacob Quint, Tannin A. Schmidt, Ali Tamayol, Indranil Sinha Jul 2021

In Vivo Printing Of Growth Factor-Eluting Adhesive Scaffolds Improves Wound Healing, Kristo Nuutila, Mohamadmahdi Samandari, Yori Endo, Yuteng Zhang, Jacob Quint, Tannin A. Schmidt, Ali Tamayol, Indranil Sinha

Department of Mechanical and Materials Engineering: Faculty Publications

Acute and chronic wounds affect millions of people around the world, imposing a growing financial burden on patients and hospitals. Despite the application of current wound management strategies, the physiological healing process is disrupted in many cases, resulting in impaired wound healing. Therefore, more efficient and easy-to-use treatment modalities are needed. In this study, we demonstrate the benefit of in vivo printed, growth factor-eluting adhesive scaffolds for the treatment of full-thickness wounds in a porcine model. A custom-made handheld printer is implemented to finely print gelatin-methacryloyl (GelMA) hydrogel containing vascular endothelial growth factor (VEGF) into the wounds. In vitro and …

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Control Of Change Of Phase Through Physical Surface Shaping, Troy Anderson, Sidy Ndao, Craig Zuhlke, Dennis Alexander, George Gogos Jun 2021

Control Of Change Of Phase Through Physical Surface Shaping, Troy Anderson, Sidy Ndao, Craig Zuhlke, Dennis Alexander, George Gogos

Department of Mechanical and Materials Engineering: Faculty Publications

A system embodiment includes , but is not limited to , a solid structure configure to contact each of a material in a liquid phase and a material in a vapor phase , the solid structure including a plurality of microstructures protruding at angles relative to a horizontal plane ; and a layer of nanoparticles positioned on the plurality of microstructures , the layer of nanoparticles having a composition that is at least one of a same material as the plurality of microstructures and an oxide of the same material as the plurality of microstructures , the plurality of microstructures …

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Atomistic Thermo-Mechanical Description Of The Deformation Behavior, Scaling Laws, And Constitutive Modeling Of Nanoporous Gold, Mohammed Hassan Yousef Saffarini Jun 2021

Atomistic Thermo-Mechanical Description Of The Deformation Behavior, Scaling Laws, And Constitutive Modeling Of Nanoporous Gold, Mohammed Hassan Yousef Saffarini

LSU Doctoral Dissertations

Metallic foams, or nanoporous (NP) metals as it is widely referred to in literature, with ligament sizes up to a few tens of nm show exceptional mechanical properties such as high strength and stiffness per weight ratio under different loading scenarios due to their high surface area to solid volume ratio. Therefore, they can be utilized in a wide range of applications making them of great interest to researchers. While their elasticity and yield strength have been the subject of several studies, very limited attention was given to the effect of size, strain rate, and temperature on the material plastic …

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Preventing Transmission Of Covid 19 In Hvac Duct Systems: Implementations Of Hvac System Design Upgrade, Jacob S. Lopez, Adama Barro Jun 2021

Preventing Transmission Of Covid 19 In Hvac Duct Systems: Implementations Of Hvac System Design Upgrade, Jacob S. Lopez, Adama Barro

Publications and Research

The recent pandemic outbreak has triggered a global alarm to increase efforts on finding the best methods to mitigate contagious viral pathogens. This project is a continuation of our mission to study engineering guidelines needed to implement upgrades to HVAC Systems in order to deter airborne pathogens such as the covid-19 virus. In our previous projects we researched how covid-19 can possibly flow through the ambient air inside of restaurants, office spaces, and locomotive train cabins. As we continued our research, we were able to find some solutions that will be best used to deactivate and prevent the virus from …

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Minimally Invasive Delivery Of 3d Shape Recoverable Constructs With Ordered Structures For Tissue Repair, Shixuan Chen, Mark Alan Carlson, Xiaowei Li, Aleem Siddique, Wuqiang Zhu, Jingwei Xie Jun 2021

Minimally Invasive Delivery Of 3d Shape Recoverable Constructs With Ordered Structures For Tissue Repair, Shixuan Chen, Mark Alan Carlson, Xiaowei Li, Aleem Siddique, Wuqiang Zhu, Jingwei Xie

Department of Mechanical and Materials Engineering: Faculty Publications

Minimally invasive procedures are becoming increasingly more common in surgery. However, the biomaterials capable of delivering biomimetic, three-dimensional (3D) functional tissues in a minimally invasive manner and exhibiting ordered structures after delivery are lacking. Herein, we reported the fabrication of gelatin methacryloyl (GelMA)-coated, 3D expanded nanofiber scaffolds and their potential applications in minimally invasive delivery of 3D functional tissue constructs with ordered structures and clinically appropriate sizes (4 cm × 2 cm × 1.5 mm). GelMA-coated, expanded 3D nanofiber scaffolds produced by combining electrospinning, gas-foaming expansion, hydrogel coating, and crosslinking are extremely shape recoverable after release of compressive strain, displaying …

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The Effects Of The Transient And Performance Loss Rates On Pv Output Performance, Chibuisi Chinasaokwu Okorieimoh, Brian Norton, Michael Conlon Jun 2021

The Effects Of The Transient And Performance Loss Rates On Pv Output Performance, Chibuisi Chinasaokwu Okorieimoh, Brian Norton, Michael Conlon

Conference papers

Solar photovoltaic (PV) panels experience long-term performance degradation as compared to their initial performance, resulting in lower like-per-like efficiencies and performance ratios. Manufacturers of solar photovoltaic modules normally guarantee a lifespan of more than 20 years. To meet such commitments, it is important to monitor and mitigate PV module degradation during this period, as well as beyond, to recognize maintenance and repair needs. Solar PV modules degrade over time, becoming less effective, less reliable, and eventually unusable. The effects of transient and performance loss rates on the output performance of polycrystalline silicon (p-Si) solar PV modules are the focus of …

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Maize Tassel Detection From Uav Imagery Using Deep Learning, Aziza Alzadjali, Mohammed H. Alali, Arun Narenthiran Weeranampalayam Sivakumar, Jitender S. Deogun, Stephen Scott, James C. Schnable, Yeyin Shi Jun 2021

Maize Tassel Detection From Uav Imagery Using Deep Learning, Aziza Alzadjali, Mohammed H. Alali, Arun Narenthiran Weeranampalayam Sivakumar, Jitender S. Deogun, Stephen Scott, James C. Schnable, Yeyin Shi

Department of Mechanical and Materials Engineering: Faculty Publications

The timing of flowering plays a critical role in determining the productivity of agricultural crops. If the crops flower too early, the crop would mature before the end of the growing season, losing the opportunity to capture and use large amounts of light energy. If the crops flower too late, the crop may be killed by the change of seasons before it is ready to harvest. Maize flowering is one of the most important periods where even small amounts of stress can significantly alter yield. In this work, we developed and compared two methods for automatic tassel detection based on …

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Uavs For Vegetation Monitoring: Overview And Recent Scientific Contributions, Ana I. De Castro, Yeyin Shi, Joe Mari Maja, Jose M. Pena May 2021

Uavs For Vegetation Monitoring: Overview And Recent Scientific Contributions, Ana I. De Castro, Yeyin Shi, Joe Mari Maja, Jose M. Pena

Department of Mechanical and Materials Engineering: Faculty Publications

This paper reviewed a set of twenty-one original and innovative papers included in a special issue on UAVs for vegetation monitoring, which proposed new methods and techniques applied to diverse agricultural and forestry scenarios. Three general categories were considered: (1) sensors and vegetation indices used, (2) technological goals pursued, and (3) agroforestry applications. Some investigations focused on issues related to UAV flight operations, spatial resolution requirements, and computation and data analytics, while others studied the ability of UAVs for characterizing relevant vegetation features (mainly canopy cover and crop height) or for detecting different plant/crop stressors, such as nutrient content/deficiencies, water …

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Three-Dimensional Shape Analysis Of Peripapillary Retinal Pigment Epithelium-Basement Membrane Layer Based On Oct Radial Images, Junfei Tong, Pengfei Dong, Sachin Kedar, Deepta Ghate, Linxia Gu May 2021

Three-Dimensional Shape Analysis Of Peripapillary Retinal Pigment Epithelium-Basement Membrane Layer Based On Oct Radial Images, Junfei Tong, Pengfei Dong, Sachin Kedar, Deepta Ghate, Linxia Gu

Department of Mechanical and Materials Engineering: Faculty Publications

The peripapillary retinal pigment epithelium-basement membrane (ppRPE/BM) layer angle was recently proposed as a potential index for estimating intracranial pressure noninvasively. However, the ppRPE/BM layer angle, measured from the optical coherence tomography (OCT) scans, varied across the radial directions of the optic disc. This made the ppRPE/BM layer angle difficult to be utilized in its full potential. In this study, we developed a mathematical model to quantify the ppRPE/BM layer angles across radial scans in relation to the ppRPE/BM 3D morphology in terms of its 3D angle and scanning tilt angles. Results showed that the variations of the ppRPE/BM layer …

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On The Comparison Of Flow Physics Between Minimal And Extended Flow Units In Turbulent Channels, Ethan A. Davis, Siamak Mirfendereski, Jae Sung Park May 2021

On The Comparison Of Flow Physics Between Minimal And Extended Flow Units In Turbulent Channels, Ethan A. Davis, Siamak Mirfendereski, Jae Sung Park

Department of Mechanical and Materials Engineering: Faculty Publications

Direct numerical simulations were performed to study the effects of the domain size of a minimal flow unit (MFU) and its inherent periodic boundary conditions on flow physics of a turbulent channel flow in a range of 200 ≤ Reτ ≤ 1000. This was accomplished by comparing turbulent statistics with those computed in sub-domains (SD) of extended domain simulations. The dimensions of the MFU and SD were matched, and SD dynamics were set to minimize artificial periodicities. Streamwise and spanwise dimensions of healthy MFUs were found to increase linearly with Reynolds number. It was also found that both MFU …

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Mixed Mode Crack Propagation In Iliac Bone, E. Baesu, Dm. Iliescu, Bv. Radoiu, S. Halichidis Apr 2021

Mixed Mode Crack Propagation In Iliac Bone, E. Baesu, Dm. Iliescu, Bv. Radoiu, S. Halichidis

Department of Mechanical and Materials Engineering: Faculty Publications

Bone is a complex material that can be regarded as an anisotropic elastic composite material. The problem of crack propagation in hu- man bone is analyzed by using a generalization of the maximum tensile stress criterion (MTS). The results concern the critical stress for crack propagation and the direction of the crack path in Iliac bone.

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