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2018

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Articles 31 - 55 of 55

Full-Text Articles in Other Engineering Science and Materials

An Integrated Microstructural-Nanomechanical-Chemical Approach To Examine Material-Specific Characteristics Of Cementitious Interphase Regions, Mahdieh Khedmati, Yong-Rak Kim, Joseph A. Turner, Hani Alanazi, Charles Nguyen Jan 2018

An Integrated Microstructural-Nanomechanical-Chemical Approach To Examine Material-Specific Characteristics Of Cementitious Interphase Regions, Mahdieh Khedmati, Yong-Rak Kim, Joseph A. Turner, Hani Alanazi, Charles Nguyen

Department of Mechanical and Materials Engineering: Faculty Publications

Effective properties and structural performance of cementitious mixtures are substantially governed by the quality of the interphase region because it acts as a bridge transferring forces between aggregates and a binding matrix and is generally susceptible to damage. As alternative binding agents like alkali-activated precursors have obtained substantial attention in recent years, there is a growing need for fundamental knowledge to uncover interphase formation mechanisms. In this paper, two different types of binding materials, i.e., fly ash-based geopolymer and ordinary portland cement, were mixed with limestone aggregate to examine and compare the microstructures and nanomechanical properties of interphase region. To …

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Methods, Systems, And Devices For Surgical Access And Procedures, Shane M. Farritor, Mark Rentschler, Amy Lehman, Stephen R. Platt, Jeff Hawks Jan 2018

Methods, Systems, And Devices For Surgical Access And Procedures, Shane M. Farritor, Mark Rentschler, Amy Lehman, Stephen R. Platt, Jeff Hawks

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 actuation system embodiments, including fluid actuation systems, drive train actuation systems, and motorless actuation systems. Additional embodiments include a reversibly lockable tube that can provide access for a medical device to a patient's cavity and further provides a reversible rigidity or stability during operation of the device. Further embodiments include various operational components for medical devices, including medical device arm mechanisms that have both axial and rotational movement while maintaining a relatively compact …

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Excess Charge-Carrier Induced Instability Of Hybrid Perovskites, Yuze Lin, Bo Chen, Yanjun Fang, Jingjing Zhao, Chunxiong Bao, Zhenhua Yu, Yehao Deng, Peter N. Rudd, Yanfa Yan, Yongbo Yuan, Jinsong Huang Jan 2018

Excess Charge-Carrier Induced Instability Of Hybrid Perovskites, Yuze Lin, Bo Chen, Yanjun Fang, Jingjing Zhao, Chunxiong Bao, Zhenhua Yu, Yehao Deng, Peter N. Rudd, Yanfa Yan, Yongbo Yuan, Jinsong Huang

Department of Mechanical and Materials Engineering: Faculty Publications

Identifying the origin of intrinsic instability for organic–inorganic halide perovskites (OIHPs) is crucial for their application in electronic devices, including solar cells, photodetectors, radiation detectors, and light-emitting diodes, as their efficiencies or sensitivities have already been demonstrated to be competitive with commercial available devices. Here we show that free charges in OIHPs, whether generated by incident light or by current-injection from electrodes, can reduce their stability, while efficient charge extraction effectively stabilizes the perovskite materials. The excess of both holes and electrons reduce the activation energy for ion migration within OIHPs, accelerating the degradation of OIHPs, while the excess holes …

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Visible Light Crosslinkable Human Hair Keratin Hydrogels, Kan Yue, Yanhui Liu, Batzaya Byambaa, Vaishali Singh, Wanjun Liu, Xiuyu Li, Yunxia Sun, Yu Shrike Zhang, Ali Tamayol, Peihua Zhang, Kee Woei Ng, Nasim Annabi, Ali Khademhosseini Jan 2018

Visible Light Crosslinkable Human Hair Keratin Hydrogels, Kan Yue, Yanhui Liu, Batzaya Byambaa, Vaishali Singh, Wanjun Liu, Xiuyu Li, Yunxia Sun, Yu Shrike Zhang, Ali Tamayol, Peihua Zhang, Kee Woei Ng, Nasim Annabi, Ali Khademhosseini

Department of Mechanical and Materials Engineering: Faculty Publications

Keratins extracted from human hair have emerged as a promising biomaterial for various biomedical applications, partly due to their wide availability, low cost, minimal immune response, and the potential to engineer autologous tissue constructs. However, the fabrication of keratin-based scaffolds typically relies on limited crosslinking mechanisms, such as via physical interactions or disulfide bond formation, which are time-consuming and result in relatively poor mechanical strength and stability. Here, we report the preparation of photocrosslinkable keratin-polyethylene glycol (PEG) hydrogels via the thiol-norbornene “click” reaction, which can be formed within one minute upon irradiation of visible light. The resulting keratin-PEG hydrogels showed …

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Methods, Systems, And Devices Relating To Force Control Surgical Systems, Shane M. Farritor, Thomas Frederick, Kearney Lackas, Joe Bartels, Jacob Greenburg Jan 2018

Methods, Systems, And Devices Relating To Force Control Surgical Systems, Shane M. Farritor, Thomas Frederick, Kearney Lackas, Joe Bartels, Jacob Greenburg

Department of Mechanical and Materials Engineering: Faculty Publications

The various embodiments herein relate to robotic surgical systems and devices that use force and/or torque sensors to measure forces applied at various components of the system or device. Certain implementations include robotic surgical devices having one or more force/torque sensors that detect or measure one or more forces applied at or on one or more arms. Other embodiments relate to systems having a robotic surgical device that has one or more sensors and an external controller that has one or more motors such that the sensors transmit information that is used at the controller to actuate the motors to …

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Frequency Dependent Deformation Reversibility During Cyclic Loading, Shuai Shao, Michael M. Khonsari, Jian Wang, Nima Shamsaei, Nan Li Jan 2018

Frequency Dependent Deformation Reversibility During Cyclic Loading, Shuai Shao, Michael M. Khonsari, Jian Wang, Nima Shamsaei, Nan Li

Department of Mechanical and Materials Engineering: Faculty Publications

High-frequency testing (HFT) is useful for accelerated fatigue testing of conventional materials that typically serve under low-frequency loading conditions, as well as for the assessment of the robustness of microelectromechanical systems which typically experience high-frequency service conditions. Using discrete dislocation dynamics, we attempt to elucidate the effect of loading frequency on the reversibility of cyclic deformation. We demonstrate that the HFT induces a higher fraction of reversible cyclic deformation because of a larger portion of elastic/anelastic deformation due to limited dislocation mobility, and a higher degree of reversibility in plastic deformation owing to the less occurrence of cross-slip.

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Investigation Of Toppling Ball Flight In American Football With A Mechanical Field-Goal Kicker, Chase M Pfeifer, Timothy J. Gay, Jeff A. Hawks, Shane Farritor, Judith M. Burnfield Jan 2018

Investigation Of Toppling Ball Flight In American Football With A Mechanical Field-Goal Kicker, Chase M Pfeifer, Timothy J. Gay, Jeff A. Hawks, Shane Farritor, Judith M. Burnfield

Department of Mechanical and Materials Engineering: Faculty Publications

A mechanical field-goal kicking machine was used to investigate toppling ball flight in American football place-kicking, eliminating a number of uncontrollable impact variables present with a human kicker. Ball flight trajectories were recorded using a triangulation-based projectile tracking system to account for the football’s 3-dimensional position during flight as well as initial launch conditions. The football flights were described using kinematic equations relating to projectile motion including stagnant air drag and were compared to measured trajectories as well as projectile motion equations that exclude stagnant air drag. Measured football flight range deviations from the non-drag equations of projectile motion corresponded …

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Manufacturing A Composite Wheel Prototype Using 3d Printed Molds, Steven Thuening Jan 2018

Manufacturing A Composite Wheel Prototype Using 3d Printed Molds, Steven Thuening

All Graduate Theses, Dissertations, and Other Capstone Projects

Throughout the evolution of high performance racing, a large emphasis has been on reducing the weight of the vehicle in order to improve its performance. Over the years, new designs and materials have been introduced reducing weight in a variety of different locations. Comparing weight reduced in different areas has shown that some areas are more valuable to reduce than others are. Perhaps one of the most beneficial locations are the wheels. This is because the mass of the wheel is considered unsprung and rotational. Because of this, large improvements towards the reduction of wheel mass have been developed in …

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An Integrated Microstructural-Nanomechanical-Chemical Approach To Examine Material-Specific Characteristics Of Cementitious Interphase Regions, Mahdieh Khedmati, Yong-Rak Kim, Joesph A. Turner, Hani Alanazi, Charles Nguyen Jan 2018

An Integrated Microstructural-Nanomechanical-Chemical Approach To Examine Material-Specific Characteristics Of Cementitious Interphase Regions, Mahdieh Khedmati, Yong-Rak Kim, Joesph A. Turner, Hani Alanazi, Charles Nguyen

Department of Mechanical and Materials Engineering: Faculty Publications

Effective properties and structural performance of cementitious mixtures are substantially governed by the quality of the interphase region because it acts as a bridge transferring forces between aggregates and a binding matrix and is generally susceptible to damage. As alternative binding agents like alkali-activated precursors have obtained substantial attention in recent years, there is a growing need for fundamental knowledge to uncover interphase formation mechanisms. In this paper, two different types of binding materials, i.e., fly ash-based geopolymer and ordinary portland cement, were mixed with limestone aggregate to examine and compare the microstructures and nanomechanical properties of interphase region. To …

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Neuroprotective And Anti-Inflammatory Effects Of Rhus Coriaria Extract In A Mouse Model Of Ischemic Optic Neuropathy, Saba Khalilpour, Ghazaleh Behnammanesh, Fouad Suede, Mohammed O. Ezzat, Jayadhisan Muniandy, Yasser Tabana, Mohamed B. K. Ahamed, Ali Tamayol, Amin Malik Shah Majid, Enrico Sangiovanni, Mario Dell'agli, Aman Shah Majid Jan 2018

Neuroprotective And Anti-Inflammatory Effects Of Rhus Coriaria Extract In A Mouse Model Of Ischemic Optic Neuropathy, Saba Khalilpour, Ghazaleh Behnammanesh, Fouad Suede, Mohammed O. Ezzat, Jayadhisan Muniandy, Yasser Tabana, Mohamed B. K. Ahamed, Ali Tamayol, Amin Malik Shah Majid, Enrico Sangiovanni, Mario Dell'agli, Aman Shah Majid

Department of Mechanical and Materials Engineering: Faculty Publications

Modulating oxidative stresses and inflammation can potentially prevent or alleviate the pathological conditions of diseases associated with the nervous system, including ischemic optic neuropathy. In this study we evaluated the anti-neuroinflammatory and neuroprotective activities of Rhus coriaria (R. coriaria) extract in vivo. The half maximal inhibitory concentration (IC50) for DPPH, ABTS and B-carotene were 6.79 ± 0.009 µg/mL, 10.94 ± 0.09 µg/mL, and 6.25 ± 0.06 µg/mL, respectively. Retinal ischemia was induced by optic nerve crush injury in albino Balb/c mice. The anti-inflammatory activity of ethanolic extract of R. coriaria (ERC) and linoleic acid (LA) on …

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Molecular Doping Enabled Scalable Blading Of Efficient Hole-Transport-Layer-Free Perovskite Solar Cells, Wu-Qiang Wu, Qi Wang, Yanjun Fang, Yuchuan Shao, Shi Tang, Yehao Deng, Haidong Lu, Ye Liu, Tao Li, Zhibin Yang, Alexei Gruverman, Jinsong Huang Jan 2018

Molecular Doping Enabled Scalable Blading Of Efficient Hole-Transport-Layer-Free Perovskite Solar Cells, Wu-Qiang Wu, Qi Wang, Yanjun Fang, Yuchuan Shao, Shi Tang, Yehao Deng, Haidong Lu, Ye Liu, Tao Li, Zhibin Yang, Alexei Gruverman, Jinsong Huang

Department of Mechanical and Materials Engineering: Faculty Publications

The efficiencies of perovskite solar cells (PSCs) are now reaching such consistently high levels that scalable manufacturing at low cost is becoming critical. However, this remains challenging due to the expensive hole-transporting materials usually employed, and difficulties associated with the scalable deposition of other functional layers. By simplifying the device architecture, hole-transport-layer-free PSCs with improved photovoltaic performance are fabricated via a scalable doctor-blading process. Molecular doping of halide perovskite films improved the conductivity of the films and their electronic contact with the conductive substrate, resulting in a reduced series resistance. It facilitates the extraction of photoexcited holes from perovskite directly …

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Flow Patterns Through Vascular Graft Models With And Without Cuffs, Chia Min Leong, Gary B. Nackman, Timothy Wei Jan 2018

Flow Patterns Through Vascular Graft Models With And Without Cuffs, Chia Min Leong, Gary B. Nackman, Timothy Wei

Department of Mechanical and Materials Engineering: Faculty Publications

The shape of a bypass graft plays an important role on its efficacy. Here, we investigated flow through two vascular graft designs±with and without cuff at the anastomosis. We conducted Digital Particle Image Velocimetry (DPIV) measurements to obtain the flow field information through these vascular grafts. Two pulsatile flow waveforms corresponding to cardiac cycles during the rest and the excitation states, with 10% and without retrograde flow out the proximal end of the native artery were examined. In the absence of retrograde flow, the straight end-to-side graft showed recirculation and stagnation regions that lasted throughout the full cardiac cycle with …

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Dislocations Interaction Induced Structural Instability In Intermetallic Al2cu, Qing Zhou, Jian Wang, Amit Misra, Ping Huang, Fei Wang, Kewei Xu Jan 2018

Dislocations Interaction Induced Structural Instability In Intermetallic Al2cu, Qing Zhou, Jian Wang, Amit Misra, Ping Huang, Fei Wang, Kewei Xu

Department of Mechanical and Materials Engineering: Faculty Publications

Intermetallic precipitates are widely used to tailor mechanical properties of structural alloys but are often destabilized during plastic deformation. Using atomistic simulations, we elucidate structural instability mechanisms of intermetallic precipitates associated with dislocation motion in a model system of Al2Cu. Interaction of non-coplanar <001> dislocation dipoles during plastic deformation results in anomalous reactions—the creation of vacancies accompanied with climb and collective glide of <001> dislocation associated with the dislocation core change and atomic shuffle—accounting for structural instability in intermetallic Al2Cu. This process is profound with decreasing separation of non-coplanar dislocations and increasing temperature and is likely to be …

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Mechanical Performance Of Plla Stent, Longzhen Wang, Junfei Tong, Pengfei Dong, David L. Wilson, Hiram G. Bezerra, Linxia Gu Jan 2018

Mechanical Performance Of Plla Stent, Longzhen Wang, Junfei Tong, Pengfei Dong, David L. Wilson, Hiram G. Bezerra, Linxia Gu

Department of Mechanical and Materials Engineering: Faculty Publications

Stent implantation is widely used to treat blocked lumen. Stents were meshed structure made of polymers and metal alloys, including stainless steel, cobalt chrome and nitinol [1]. Clinical studies had demonstrated that stents helped to scaffold the diseased lesion up to one year when tissue adapted to the stented environment [2]. However, the permanently implanted stents inside artery were associated with complications such as stent fracture, tissue inflammation, in-stent restenosis and thrombosis [3]. Currently, biodegradable stents are attracting more attention due to its potential long-term efficacy in treating blocked lumens. The detailed characterizations of biodegradable stents are essential for the …

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Plaque Burden Influences Accurate Classification Of Fibrous Cap Atheroma By In-Vivo Optical Coherence Tomography In A Porcine Model Of Advanced Coronary Atherosclerosis., Christian B. Poulsen, Ryan M. Pedrigi, Nilesh Pareek, Ismail D. Kilic, Niels R. Holm, Jacob F. Bentzon, Hans Erik Botker, Erling Falk, Rob Krams, Ranil De Silva Jan 2018

Plaque Burden Influences Accurate Classification Of Fibrous Cap Atheroma By In-Vivo Optical Coherence Tomography In A Porcine Model Of Advanced Coronary Atherosclerosis., Christian B. Poulsen, Ryan M. Pedrigi, Nilesh Pareek, Ismail D. Kilic, Niels R. Holm, Jacob F. Bentzon, Hans Erik Botker, Erling Falk, Rob Krams, Ranil De Silva

Department of Mechanical and Materials Engineering: Faculty Publications

Advanced coronary atherosclerosis assessed by in-vivo optical coherence tomography (OCT) has not been directly compared with histology. In a porcine model with human-like coronary atherosclerosis we compared in-vivo OCT images with histology in five animals. We found a high sensitivity but modest specificity of OCT in classifying fibrous cap atheroma (FCA). The modest specificity was caused by misclassification of FCA lesions as pathological intimal thickening. The misclassification most frequently occurred when plaque burden exceeded ~20%. Compared with histology, OCT has high sensitivity but modest specificity for identifying FCA. The study suggests that plaque burden should be considered when interpreting OCT …

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Multifunctional Operational Component For Robotic Devices, Shane M. Farritor, Amy Lehman, Mark Rentschler Jan 2018

Multifunctional Operational Component For Robotic Devices, Shane M. Farritor, Amy Lehman, Mark Rentschler

Department of Mechanical and Materials Engineering: Faculty Publications

The various embodiments disclosed herein relate to modular medical devices, including various devices with detachable modular components and various devices with pivotally attached modular components. Additional embodiments relate to procedures in which various of the devices are used cooperatively. Certain embodiments of the medical devices are robotic in vivo devices.

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Scaffold Structural Microenvironmental Cues To Guide Tissue Regeneration In Bone Tissue Applications, Xuening Chen, Hongyuan Fan, Xiaowei Deng, Lina Wu, Tao Yi, Linxia Gu, Changchun Zhou, Yujiang Fan, Xingdong Zhang Jan 2018

Scaffold Structural Microenvironmental Cues To Guide Tissue Regeneration In Bone Tissue Applications, Xuening Chen, Hongyuan Fan, Xiaowei Deng, Lina Wu, Tao Yi, Linxia Gu, Changchun Zhou, Yujiang Fan, Xingdong Zhang

Department of Mechanical and Materials Engineering: Faculty Publications

In the process of bone regeneration, new bone formation is largely affected by physico-chemical cues in the surrounding microenvironment. Tissue cells reside in a complex scaffold physiological microenvironment. The scaffold should provide certain circumstance full of structural cues to enhance multipotent mesenchymal stem cell (MSC) differentiation, osteoblast growth, extracellular matrix (ECM) deposition, and subsequent new bone formation. This article reviewed advances in fabrication technology that enable the creation of biomaterials with well-defined pore structure and surface topography, which can be sensed by host tissue cells (esp., stem cells) and subsequently determine cell fates during differentiation. Three important cues, including scaffold …

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Heat Transfer Across A Nanoscale Pressurized Air Gap And Its Application In Magnetic Recording, Jinglin Zheng, Yung-Kan Chen, Qin Zhou Jan 2018

Heat Transfer Across A Nanoscale Pressurized Air Gap And Its Application In Magnetic Recording, Jinglin Zheng, Yung-Kan Chen, Qin Zhou

Department of Mechanical and Materials Engineering: Faculty Publications

In this study, we investigated how a thermally actuated air bearing slider heats up a fast-spinning storage disk through a highly pressurized nanoscale air gap in a magnetic recording system. A Euleriandescription- based computational approach is developed considering heat conduction through a pressurized air film and near-field radiation across the gap. A set of field equations that govern the air bearing dynamics, slider thermo-mechanics and disk heat dissipation are solved simultaneously through an iterative approach. A temperature field on the same order as the hot slider surface itself is found to be established in the disk. The effective local heat …

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Interfacial Characterization By Pull-Out Test Of Bamboo Fibers Embedded In Poly(Lactic Acid), Quentin Viel, Antonella Esposito, Jean-Marc Saiter, Carlo Santulli, Joseph A. Turner Jan 2018

Interfacial Characterization By Pull-Out Test Of Bamboo Fibers Embedded In Poly(Lactic Acid), Quentin Viel, Antonella Esposito, Jean-Marc Saiter, Carlo Santulli, Joseph A. Turner

Department of Mechanical and Materials Engineering: Faculty Publications

In this work, the apparent shear strength at the interface between a bamboo fiber and the surrounding poly(lactic acid) (PLA) matrix is quantified. A method for processing pull-out test samples within a controlled embedded length is proposed and the details of the test procedure are presented, along with a critical discussion of the results. Two series of samples are considered: untreated and mercerized bamboo fibers from the same batch, embedded in the same polyester matrix. Electron and optical microscopy are used to observe the fiber–matrix interface before and after the test, and to identify the failure mode of each sample, …

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Complementary Microscopy Techniques Applied For Characterizing The Localized Nanoscale Structure Of Poly (Vinylidene Fluoride), Wen Qian, Shuo Sun, Charles Nguyen, Wenlong Li, Stephen Ducharme, Joesph A. Turner Jan 2018

Complementary Microscopy Techniques Applied For Characterizing The Localized Nanoscale Structure Of Poly (Vinylidene Fluoride), Wen Qian, Shuo Sun, Charles Nguyen, Wenlong Li, Stephen Ducharme, Joesph A. Turner

Department of Mechanical and Materials Engineering: Faculty Publications

Poly (vinylidenefluoride) (PVDF), a well-recognized electroactive polymer, has been studied extensively over many decades. Recently, there has been increasing interest in tuning the electrical properties of PVDF from ferroelectric to piezoelectric and to pyroelectric, which can be attained via controlling the microscale structure down to the nanoscale structure [1-2]. To optimize the preparation conditions of PVDF and its copolymers, as well as to improve the performance for many applications, comprehensive analytical techniques are of great importance. In this paper, we demonstrate complementary nanoscale characterization and measurement techniques, by conducting a systematic and coordinated study involving scanning electron microscopy (SEM), high …

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Improved A-B10C2+XHY/Si P-N Heterojunction Performance After Neutron Irradiation, George Peterson, Qing Su, Yongqiang Wang, Natale J. Ianno, Peter Dowben, Michael Nastasi Jan 2018

Improved A-B10C2+XHY/Si P-N Heterojunction Performance After Neutron Irradiation, George Peterson, Qing Su, Yongqiang Wang, Natale J. Ianno, Peter Dowben, Michael Nastasi

Department of Mechanical and Materials Engineering: Faculty Publications

The impact of neutron irradiation, in the energy range of ~0.025 eV, on amorphous semiconducting partially dehydrogenated boron carbide (a-B10C2+xHy) on silicon p-n heterojunction diodes was investigated. The heterojunction devices were created by synthesizing a-B10C2+xHy via plasma enhanced chemical vapor deposition on n-type silicon. Unlike many electronic devices, the performance of the a-B10C2+xHy heterojunction diode improved with neutron irradiation, in spite of the large neutron cross section of 10B. There is also increased charge carrier lifetime of more than …

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Tissue Stresses In Stented Coronary Arteries With Different Geometries: Effect Of The Relation Between Stent Length And Lesion Length, Xiang Shen, Song Ji, Yong-Quan Deng, Hong-Fei Zhu, Jia-Bao Jiang, Linxia Gu Jan 2018

Tissue Stresses In Stented Coronary Arteries With Different Geometries: Effect Of The Relation Between Stent Length And Lesion Length, Xiang Shen, Song Ji, Yong-Quan Deng, Hong-Fei Zhu, Jia-Bao Jiang, Linxia Gu

Department of Mechanical and Materials Engineering: Faculty Publications

In-stent restenosis after stent deployment remains an obstruction in the long-term benefits of stenting. This study sought to investigate the influence of the relation between stent length and lesion length on the mechanics of the arterial wall with different geometries, including straight and tapered vessels. Results showed that when the length of the stent was longer than the lesion length, the maximum stress in plaque and vessel increased as the length of stent increased. When the length of the stent was shorter than the lesion length, the vessel stress induced by stent inflation was lower; both ends of the stenosis …

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Experimental Measurement Of Dolphin Thrust Generated During A Tail Stand Using Dpiv, Frank E. Fish, Terrie M. Williams, Erica Sherman, Yae Eun Moon, Vicki Wu, Timothy Wei Jan 2018

Experimental Measurement Of Dolphin Thrust Generated During A Tail Stand Using Dpiv, Frank E. Fish, Terrie M. Williams, Erica Sherman, Yae Eun Moon, Vicki Wu, Timothy Wei

Department of Mechanical and Materials Engineering: Faculty Publications

Estimation of force generated by dolphins has long been debated. The problem was that indirect estimates of force production for dolphins resulted in low values that could not be validated. Bubble digital particle image velocimetry (DPIV) measured hydrodynamic force production for swimming dolphins and demonstrated high force production. To validate the bubble DPIV and reconcile force production measurements, two bottlenose dolphins (Tursiops truncatus) performing tail stands were measured with bubble DPIV. Microbubbles were generated from a finely porous hose and compressed air source. Displacement of the bubbles by the propulsive motions of the dolphin was tracked with a …

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Structural And Aerodynamic Design, Procedure And Analysis Of A Small V-Shaped Vertical Axis Wind Turbine, Odari J. Whyte Jan 2018

Structural And Aerodynamic Design, Procedure And Analysis Of A Small V-Shaped Vertical Axis Wind Turbine, Odari J. Whyte

College of Graduate Studies: Theses & Dissertations

Over the last two decades there has been a renewed interest in Vertical Axis Wind Turbines. This turbine configuration though unpopular for large-scale generation has found a niche market in the way of offshore energy harvesting. However, offshore wind has its challenges. In this thesis a detailed comprehensive study of a proposed V-shaped vertical axis turbine rotor is performed in order to examine its structural and aerodynamic characteristics. The design met and exceeded the safety parameters establish for test bed operation, showing a factor of safety of 1.87 with regard to fatigue stress response. A satisfactory fatigue stress design life …

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Influence Of Substrate Stage Temperature And Rotation Rate On The Magneto-Optical Quality Of Rf-Sputtered Bi2.1dy0.9fe3.9ga1.1o12 Garnet Thin Films, Mohammad E. Alam, Mikhail Vasiliev, Kamal Alameh Jan 2018

Influence Of Substrate Stage Temperature And Rotation Rate On The Magneto-Optical Quality Of Rf-Sputtered Bi2.1dy0.9fe3.9ga1.1o12 Garnet Thin Films, Mohammad E. Alam, Mikhail Vasiliev, Kamal Alameh

Research outputs 2014 to 2021

Highly bismuth-substituted iron garnet thin films are prepared on quartz substrates by using a radio frequency (RF) magnetron sputtering technique. We study the factors (process parameters associated with the RF magnetron sputter deposition technique) affecting the magneto-optical (MO) properties of ferrite garnet films of composition Bi2.1Dy0.9Fe3.9Ga1.1O12. All films show high MO response across the visible range of wavelengths after being annealed. In particular, the effects of substrate stage temperature and rotation rate on the various properties of films are studied. Experimental results reveal that the characteristics of garnet films of this type can be tuned and optimized for use in …

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