Novel Photothermal Materials And Thermally Engineered Membranes For Solar Desalination,
2021
Washington University in St. Louis
Novel Photothermal Materials And Thermally Engineered Membranes For Solar Desalination, Sisi Cao
McKelvey School of Engineering Theses & Dissertations
Although 71% of earth surface is covered with water, more than 97% of it is saltwater, and freshwater is limited to only about 2.5%. The freshwater shortage has been exacerbated due to the environmental pollution, increased agriculture needs, socio-economic development, and population growth. Among various desalination technologies, membrane distillation has gained wide attention due to its ability to treat highly saline water utilizing waste heat from industrial processes. However, the implementation of conventional membrane distillation is hindered in the remote regions and disaster-struck communities where the low-grade thermal energy from industrial plants and electricity are not readily available. To address …
Nucleation Studies In Barium Silicate Glasses And Soda-Lime Silicate Glass,
2021
Washington University in St. Louis
Nucleation Studies In Barium Silicate Glasses And Soda-Lime Silicate Glass, Xinsheng Xia
McKelvey School of Engineering Theses & Dissertations
Controlling nucleation is key for the manufacture of glasses and glass-ceramics. It has been observed by different researchers in many silicate glasses that at low temperatures the critical work of cluster formation (i.e. the nucleation barrier) slowly rises rather than decreasing with decreasing temperature. However, this experimental observation is in contradiction with nucleation theories. In this dissertation, crystal nucleation was studied in BaO·2SiO2, 5BaO·8SiO2, and Na2O·2CaO·3SiO2 glasses. The main research topics include measurements of the nucleation rate, the structural evolution of the glass, and the low-temperature nucleation behavior. A special focus is given to the low-temperature nucleation anomaly. In total, …
Structure-Property Relationship In High Strength- High Ductility Combination Austenitic Stainless Steels,
2021
University of Texas at El Paso
Structure-Property Relationship In High Strength- High Ductility Combination Austenitic Stainless Steels, Chengyang Hu
Open Access Theses & Dissertations
Austenitic stainless steels are widely used in our daily life, but their mechanical strength is low. In order to improve their yield strength via grain refinement, an investigation was carried out involving phase reversion annealing concept comprising of severe cold roll reduction followed by annealing at different temperatures for short durations. During annealing reversion of deformation-induced martensite to austenite occurred by shear mechanism, leading to fine-grained structure and high strength-high ductility combination.Nanoscale deformation studies suggested that the deformation mechanism of nanograined structure was different from the coarse-grained counterpart. Post-mortem electron microscopy of plastic zone surrounding the indent indicated that the …
Magnesiothermic Combustion Synthesis Of Nanocrystalline Silicon And Oxidation Kinetics Of Magnesium Particles,
2021
University of Texas at El Paso
Magnesiothermic Combustion Synthesis Of Nanocrystalline Silicon And Oxidation Kinetics Of Magnesium Particles, Sergio Cordova
Open Access Theses & Dissertations
Magnesium (Mg) is a well-known reduction agent in metallurgy (more specifically, in metallothermy). Recently, magnesiothermic reduction of oxides has been used in self-propagating high-temperature synThesis (SHS) of advanced materials such as ultrahigh-temperature ceramics (UHTC). The magnesiothermic SHS has also been used for the conversion of silica (SiO2) to silicon-based materials for thermoelectric applications. However, since oxidation of Mg releases a lot of heat, the direct use of it as the reduction agent leads to excessively high temperatures and undesirable sintering of the products. We have proposed to use magnesium silicide (Mg2Si) instead of Mg in the SHS of nanostructured silicon. …
Methods , Systems , And Devices
Relating To Surgical End Effectors,
2021
Lincoln , NE
Methods , Systems , And Devices Relating To Surgical End Effectors, Shane M. Farritor, Thomas Frederick, Joe Bartels
Mechanical & 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.
Development Of A Wireless Telemetry Load And Displacement Sensor For Orthopaedic Applications,
2021
The University of Western Ontario
Development Of A Wireless Telemetry Load And Displacement Sensor For Orthopaedic Applications, William Anderson
Electronic Thesis and Dissertation Repository
Due to sensor size and supporting circuitry, in vivo load and deformation measurements are currently restricted to applications within larger orthopaedic implants. The objective of this thesis is to repurpose a commercially available low-power, miniature, wireless, telemetric, tire-pressure sensor (FXTH87) to measure load and deformation for future use in biomechanical applications. The capacitive transducer membrane of the FXTH87 was modified, and a relationship was reported between applied compressive deformation and sensor signal value. The sensor package was embedded within a deformable enclosure to illustrate potential applications of the sensor for monitoring load. Finite element analysis was an effective tool to …
Investigation And Statistical Modeling Of The Mechanical Properties Of Additively Manufactured Lattices,
2021
Air Force Institute of Technology
Investigation And Statistical Modeling Of The Mechanical Properties Of Additively Manufactured Lattices, Derek G. Spear, Anthony N. Palazotto
Faculty Publications
This paper describes the background, test methodology, and experimental results associated with the testing and analysis of quasi-static compression testing of additively manufactured open-cell lattice structures. The study aims to examine the effect of lattice topology, cell size, cell density, and surface thickness on the mechanical properties of lattice structures. Three lattice designs were chosen, the Diamond, I-WP, and Primitive Triply Periodic Minimal Surfaces (TPMSs). Uniaxial compression tests were conducted for every combination of the three lattice designs, three cell sizes, three cell densities, and three surface thicknesses. In order to perform an efficient experiment and gain the most information …
Robotic Surgical Devices , Systems ,
And Related Methods,
2021
Lincoln , NE
Robotic Surgical Devices , Systems , And Related Methods, Shane Farritor, Erik Mumm, Philip Chu, Nishant Kumar, Jason Dumpert, Yutaka Tsutano
Mechanical & 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.
In Vivo Printing Of Growth Factor-Eluting Adhesive Scaffolds Improves Wound Healing,
2021
Harvard Medical School
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
Mechanical & 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 …
Development Of Novel Battery Materials For Lithium-Ion Batteries And Beyond,
2021
University of Arkansas, Fayetteville
Development Of Novel Battery Materials For Lithium-Ion Batteries And Beyond, Jiyu Cai
Graduate Theses and Dissertations
As fossil fuels are depleting and causing environmental issues, it becomes imperative to widely implement renewable energies (e.g., solar and wind power). In this context, electrical energy storage (EES) systems are essential to accommodate the intermittent supply and uneven distribution of renewable energies. To this end, high-energy-density EES devices are highly demanded, such as rechargeable batteries. This dissertation presents my efforts in developing novel battery materials for lithium-ion batteries (LIBs), sodium-ion batteries (SIBs), and solidstate lithium batteries (SSLBs). These efforts include electrochemical evaluations of battery materials, surface modifications of electrodes via atomic layer deposition (ALD), and advanced characterizations of batteries …
Phase-Field Modeling Of The Polymer Membrane Formation Process For Micro- And Ultra-Filtration,
2021
University of Arkansas, Fayetteville
Phase-Field Modeling Of The Polymer Membrane Formation Process For Micro- And Ultra-Filtration, Michael Rosario Cervellere
Graduate Theses and Dissertations
Porous polymer membrane filters are widely used in separation and filtration process. Micro- and ultra-filtration membranes are commonly used in biopharmaceutical applications such as filtering viruses and separating proteins from a carrier solution. The formation of these membrane filters via phase inversion is a complex and interconnected process where varying casting conditions can have a wide variety of effects on the final membrane morphol- ogy. Tailoring membrane filters for specific performance characteristics is a tedious and time consuming process. The time and length scales of membrane formation make it extremely difficult to experimentally observe membrane formation. Modeling the membrane formation …
Electrochemical Deposition In Energy Storage Devices,
2021
University of Arkansas, Fayetteville
Electrochemical Deposition In Energy Storage Devices, Witness Atutala Martin
Graduate Theses and Dissertations
Metals, whether in a solid or soluble ion form, are a vital part of any electrochemical storage system. More so, Li metal is widely considered as the ideal anode because of its low density and low electrochemical potential (-3.04 V vs. the standard hydrogen electrode – SHE). However, just like most metals, it does not plate or strip evenly during cycling which can lead to cycling performance issues, short cycling lifespans, and even safety concerns brought about by dendrites that can cause internal short-circuiting within cells. This research focused on investigating the electroplating of metals in both aqueous and non-aqueous …
Optimization Of Vaccine Supply Chains In Low- And Middle-Income Countries Utilizing Drones,
2021
University of Arkansas, Fayetteville
Optimization Of Vaccine Supply Chains In Low- And Middle-Income Countries Utilizing Drones, Maximilian Kolter
Graduate Theses and Dissertations
Despite tremendous efforts from governments and humanitarian organizations, millions of children in low- and low-middle-income countries (LICs and LMICs) are still excluded from the benefits of immunization. The vaccine distribution in LICs and LMICs is challenging for several reasons, such as limited cold chain capacities, vaccine wastage, uncertain demand, and lack of access to immunization services. A promising avenue to address these issues is the utilization of drones for vaccine delivery. Drones can fly at high speed on direct paths and could enable on-demand deliveries to mitigate limited storage capacities. Further, their independence of road networks could allow them reaching …
A Computational Study Of Radiation Damage In Bilayer Silicon-Gold Structures,
2021
University of Arkansas, Fayetteville
A Computational Study Of Radiation Damage In Bilayer Silicon-Gold Structures, Cameron Hopper
Graduate Theses and Dissertations
Irradiation from sources such as nuclear reactors bombard materials with neutrons and heavy ions. The primary consequence of this irradiation is the displacement of atoms from their atomic structure. As the structure becomes damaged, the mechanical properties can change. Eventually, this can result in a failure due to embrittlement. This type of damage is hard to detect and can result in sudden, unexpected failure. Therefore, focusing on managing the consequences of irradiation has been a heavily researched topic. To manage irradiation, the focus is primarily to manage the voids and interstitials that appear during irradiation. Grain boundaries and amorphous regions …
Material Property Heterogeneity In Dimensional Lumber And Its Relationship To Mass Timber Performance,
2021
University of Massachusetts Amherst
Material Property Heterogeneity In Dimensional Lumber And Its Relationship To Mass Timber Performance, Fiona O'Donnell
Doctoral Dissertations
According to the Environmental Protection Agency, buildings account for 38% of the United States' carbon dioxide emissions, providing architects and structural engineers a unique opportunity to mitigate a significant factor driving climate change by implementing innovative and sustainable technology in infrastructure design. Wood and mass timber products are becoming an increasingly popular alternative building material due to their economic and environmental benefits. The natural growth of wood leads to highly heterogeneous material properties. Defects such as checks, knots, and localized slope of grain contribute to some of this variation; however, wood properties vary significantly even in clear wood. Using mass …
Control Of Change Of Phase
Through Physical Surface Shaping,
2021
NuTech Ventures
Control Of Change Of Phase Through Physical Surface Shaping, Troy Anderson, Sidy Ndao, Craig Zuhlke, Dennis Alexander, George Gogos
Mechanical & 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 …
Atomistic Thermo-Mechanical Description Of The Deformation Behavior, Scaling Laws, And Constitutive Modeling Of Nanoporous Gold,
2021
Louisiana State University
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 …
Preventing Transmission Of Covid 19 In Hvac Duct Systems: Implementations Of Hvac System Design Upgrade,
2021
CUNY New York City College of Technology
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 …
Fluid-Structure Interaction Of Nrel 5-Mw Wind Turbine,
2021
The American University in Cairo AUC
Fluid-Structure Interaction Of Nrel 5-Mw Wind Turbine, Mohamed Sayed Elkady Abd-Elhay
Theses and Dissertations
Wind energy is considered one of the major sources of renewable energy. Nowadays, wind turbine blades could exceed 100 m to maximize the generated power and minimize produced energy cost. Due to the enormous size of the wind turbines, the blades are subjected to failure by aerodynamics loads or instability issues. Also, the gravitational and centrifugal loads affect the wind turbine design because of the huge mass of the blades. Accordingly, wind turbine simulation became efficient in blade design to reduce the cost of its manufacturing. The fluid-structure interaction (FSI) is considered an effective way to study the turbine's behavior …
Minimally Invasive Delivery Of 3d Shape Recoverable Constructs With Ordered Structures For Tissue Repair,
2021
University of Nebraska Medical Center
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
Mechanical & 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 …
