Investigation Of Iron Doped Gallium Oxide (Ga-Fe-O) System: Structure Property Relationship And Performance Evaluation For Optical And Catalytic Applications,
2020
University of Texas at El Paso
Investigation Of Iron Doped Gallium Oxide (Ga-Fe-O) System: Structure Property Relationship And Performance Evaluation For Optical And Catalytic Applications, Swadipta Roy
Open Access Theses & Dissertations
From September 2012 to May 2015, a phenocam monitored the seaward edge of a protected mangrove forest. Calculated GCC revealed seasonal greening patterns of a mangrove species, Rhizophoa apiculata, and an overall increase in the GCC, suggesting mangrove expansion. In comparing temperature and precipitation effects, it was found that this particular mangrove species had a greening optima at temperatures between 28°C and 28.5°C, and greening and canopy development response lag time of 10 weeks in response to precipitation. Tree saplings were monitored and showed to grow by 50%, mostly during a three month period during the rainy season. The establishment …
Organophosphorus-Hydrazides As Potential Reactive Flame Retardants For Epoxy,
2020
University of Dayton
Organophosphorus-Hydrazides As Potential Reactive Flame Retardants For Epoxy, Alexander B. Morgan, Vladimir Benin, Donald A. Klosterman, Abdulhamid Bin Sulayman, Mustafa Mukhtar, Mary L. Galaska
Chemical and Materials Engineering Faculty Publications
For structural composites used in vehicles and aircraft, flame retardant chemistries which enhance char formation and reduce heat release are preferred. Phosphorus-based and phosphorus–nitrogen flame retardants for epoxies have been well studied to date, but phosphorus hydrazides have not been studied for their flame-retardant potential in epoxy. These hydrazides offer some novel structures and they can potentially offer a combination of vapor and condensed phase flame retardant action. A series of eight compounds were systematically investigated in this study as reactive flame retardants in a bisphenol F epoxy/aliphatic amine resin system at a level of 2.5 wt% phosphorus. Results suggest …
Gold/Qds-Embedded-Ceria Nanoparticles: Optical Fluorescence Enhancement As A Quenching Sensor,
2020
Old Dominion University
Gold/Qds-Embedded-Ceria Nanoparticles: Optical Fluorescence Enhancement As A Quenching Sensor, Nader Shehata, Effat Samir, Ishac Kandas
Electrical & Computer Engineering Faculty Publications
This work focuses on improving the fluorescence intensity of cerium oxide (ceria) nanoparticles (NPs) through added plasmonic nanostructures. Ceria nanoparticles are fluorescent nanostructures which can emit visible fluorescence emissions under violet excitation. Here, we investigated different added plasmonic nanostructures, such as gold nanoparticles (Au NPs) and Cadmium sulfide/selenide quantum dots (CdS/CdSe QDs), to check the enhancement of fluorescence intensity emissions caused by ceria NPs. Different plasmonic resonances of both aforementioned nanostructures have been selected to develop optical coupling with both fluorescence excitation and emission wavelengths of ceria. In addition, different additions whether in-situ or post-synthesis have been investigated. We found …
Thermoelectric Porous Mof Based Hybrid Materials,
2020
Old Dominion University
Thermoelectric Porous Mof Based Hybrid Materials, Engelbert Redel, Helmut Baumgart
Electrical & Computer Engineering Faculty Publications
Porous hybrid materials and MOF (Metal-Organic-Framework) films represent modern designer materials that exhibit many requirements of a near ideal and tunable future thermoelectric (TE) material. In contrast to traditional semiconducting bulk TE materials, porous hybrid MOF templates can be used to overcome some of the constraints of physics in bulk TE materials. These porous hybrid systems are amenable for simulation and modeling to design novel optimized electron-crystal phonon-glass materials with potentially very high ZT (figure of merit) numbers. Porous MOF and hybrid materials possess an ultra-low thermal conductivity, which can be further modulated by phonon engineering within their complex porous …
Observation Of Reduced Thermal Conductivity In A Metal-Organic Framework Due To The Presence Of Adsorbates,
2020
Old Dominion University
Observation Of Reduced Thermal Conductivity In A Metal-Organic Framework Due To The Presence Of Adsorbates, Hasan Babaei, Mallory E. Decoster, Minyoung Jeong, Zeinab M. Hassan, Timur Islamoglu, Helmut Baumgart, Alan J.H. Mcgaughey, Engelbert Redel, Omar K. Farha, Patrick E. Hopkins, Jonathan A. Malen, Christopher E. Wilmer
Electrical & Computer Engineering Faculty Publications
Whether the presence of adsorbates increases or decreases thermal conductivity in metal-organic frameworks (MOFs) has been an open question. Here we report observations of thermal transport in the metal-organic framework HKUST-1 in the presence of various liquid adsorbates: water, methanol, and ethanol. Experimental thermoreflectance measurements were performed on single crystals and thin films, and theoretical predictions were made using molecular dynamics simulations. We find that the thermal conductivity of HKUST-1 decreases by 40 – 80% depending on the adsorbate, a result that cannot be explained by effective medium approximations. Our findings demonstrate that adsorbates introduce additional phonon scattering in HKUST-1, …
Effect Of Layer Thickness On Structural, Morphological And Superconducting Properties Of Nb3Sn Films Fabricated By Multilayer Sequential Sputtering,
2020
Old Dominion University
Effect Of Layer Thickness On Structural, Morphological And Superconducting Properties Of Nb3Sn Films Fabricated By Multilayer Sequential Sputtering, M. N. Sayeed, U. Pudasaini, C. E. Reece, G. V. Eremeev, H. E. Elsayed-Ali
Electrical & Computer Engineering Faculty Publications
Superconducting Nb3Sn films can be synthesized by controlling the atomic concentration of Sn. Multilayer sequential sputtering of Nb and Sn thin films followed by high temperature annealing is considered as a method to fabricate Nb3Sn films, where the Sn composition of the deposited films can be controlled by the thickness of alternating Nb and Sn layers. We report on the structural, morphological and superconducting properties of Nb3Sn films fabricated by multilayer sequential sputtering of Nb and Sn films on sapphire substrates followed by annealing at 950 °C for 3 h. We have investigated the …
Design, Microstructure And Properties Of Metastable Beta-Type Biomedical Titanium Alloys,
2020
Edith Cowan University
Design, Microstructure And Properties Of Metastable Beta-Type Biomedical Titanium Alloys, Syed Faraz Jawed
Theses: Doctorates and Masters
Many existing implant biomaterials including cobalt-chromium alloy, stainless steel, Ti-6Al-4V and commercially pure titanium have all been shown to demonstrate mechanical incompatibility, poor osseointegration and/or cause cytotoxic effects on the human body after some years of application, leading to revision surgery in most cases. Consequently, there is an immediate need for an enduring biomaterial that displays good mechanical properties and possesses biocompatibility and corrosion resistance, in order to reduce rates of revision surgeries. In this PhD work, based on the 𝐵𝑜̅̅̅̅-𝑀𝑑̅̅̅̅̅, 𝑒/𝑎̅̅̅̅̅-𝛥𝑟̅̅̅ and BF-d-electron superelastic theoretical relationships four new series of quaternary Ti-25Nb-8Zr-xCr, Ti-25Nb-xSn-yCr, Ti26Nb-xMn-yZr and Ti-25Nb-xMn-ySn alloys have been …
Designing Composites For Graceful Failure,
2020
The British University in Egypt
Designing Composites For Graceful Failure, Amany G. Micheal Prof., Yehia Ahmed Bahei El Din Prof.
Architectural Engineering
When inevitable, failure in composite laminates is preferred to occur gracefully to avoid loss of property and possibly life. While the inherent inhomogeneity leads to slow dissipation of damage-related energy, overall failure is fiber-dominated and occurs in a rather brittle manner. Multidirectional plies usually give a more ductile response. Additionally, stiffness and strength as well as cost are important factors to consider in designing composite laminates. It is hence desirable to optimize for high mechanical properties and low cost while keeping graceful failure. Designing composite laminates with hybrid systems and layups, which permit gradual damage energy dissipation, are two ways …
Increasing Access To Pv Technology Through Sustainable Racking: A Review Of Existing Literature And Ground Mounted Fixed Tilt Designs, And What Can Be Done Next,
2020
Michigan Technological University
Increasing Access To Pv Technology Through Sustainable Racking: A Review Of Existing Literature And Ground Mounted Fixed Tilt Designs, And What Can Be Done Next, Parijata Prabhakara
Dissertations, Master's Theses and Master's Reports
There is a lack of literature on the structural balance of systems (BOS), also called racking, for ground mount, fixed-tilt solar PV systems. Literature that exists discusses mostly rooftop racking and installations, additional wind loading, and weight considerations imposed on roofs, and little guidance is provided in building codes. The lack of peer-reviewed guidance on design requirements for domestic and large-scale application solar PV racking systems leaves most consumers relying on expensive, patented, off-the-shelf hardware. As PV cell technology and module costs have improved, we can start to focus on PV BOS improvements (particularly racking) and move towards sustainable designs …
Virus Purification Framework And Enhancement In Aqueous Two-Phase System,
2020
Michigan Technological University
Virus Purification Framework And Enhancement In Aqueous Two-Phase System, Pratik Umesh Joshi
Dissertations, Master's Theses and Master's Reports
Viral infections regularly pose detrimental health risks to humans. Preventing viral infections through global immunization requires the production of large doses of vaccines. The increasing demand for vaccines, especially during pandemics such as COVID-19, has challenged current manufacturing strategy to develop advanced unit operations with high throughput capability. Over the decade, the upstream processing responsible for synthesizing viral products in cell cultures has shown significant success in yielding high titers of viruses and virus-like particles. The progress in the upstream stage has now shifted the bottleneck to the downstream processing (DSP). Overlooked for decades, the DSP responsible for viral product …
Sensitivity And Uncertainty Quantification Of Continuum And Stochastic Bond Dissociation Kinetics Based Cohesive Laws,
2020
Michigan Technological University
Sensitivity And Uncertainty Quantification Of Continuum And Stochastic Bond Dissociation Kinetics Based Cohesive Laws, Rishabh Awasthi
Dissertations, Master's Theses and Master's Reports
Polymeric adhesives are being extensively used to develop light weight and durable Composite Materials which are have been employed in automotive, aeronautical, medical industry. Polymeric adhesives undergo failure due to relative opening sliding of bonded interfaces which requires a need to characterize the fracture mechanism. Numerous experiments are conducted to predict the fracture response for Mode-I, II,III and numerical simulations are employed to inversely calibrate the material parameters governing the constitutive laws. Cohesive zone models are largely employed in fracture mechanics to predict failure of interfaces undergoing large plastic deformations. The objective of this report is to employ the cohesive …
Buckling Load Study On Pop Nut (Rivet) Using Finite Element Analysis,
2020
Michigan Technological University
Buckling Load Study On Pop Nut (Rivet) Using Finite Element Analysis, Saurabh Shankar Shegokar
Dissertations, Master's Theses and Master's Reports
This study highlights the material behavior in riveting operation that includes buckling load analysis using ABAQUS. Finite Element Analysis is used to find the buckling load vs. Displacement results and validated with the results obtained in physical testing of rivet (POP Nut). A mesh sensitivity study is performed using ABAQUS to understand the optimum mesh size for this analysis. An axisymmetric model with contact properties is created and simulated to reduce the simulation time using ABAQUS. The results obtained through Finite Element Analysis show a good resemblance with the testing results. Design changes were suggested to achieve better results that …
Artificial Synthetic Scaffolds For Tissue Engineering Application Emphasizing The Role Of Biophysical Cues,
2020
Michigan Technological University
Artificial Synthetic Scaffolds For Tissue Engineering Application Emphasizing The Role Of Biophysical Cues, Samerender Nagam Hanumantharao
Dissertations, Master's Theses and Master's Reports
The mechanotransduction of cells is the intrinsic ability of cells to convert the mechanical signals provided by the surrounding matrix and other cells into biochemical signals that affect several distinct processes such as tumorigenesis, wound healing, and organ formation. The use of biomaterials as an artificial scaffold for cell attachment, differentiation and proliferation provides a tool to modulate and understand the mechanotransduction pathways, develop better in vitro models and clinical remedies. The effect of topographical cues and stiffness was investigated in fibroblasts using polycaprolactone (PCL)- Polyaniline (PANI) based scaffolds that were fabricated using a self-assembly method and electrospinning. Through this …
Effect Of Cobalt In Thin Wall Ductile Iron And Solid Solution Strengthened Ferritic Ductile Iron,
2020
Michigan Technological University
Effect Of Cobalt In Thin Wall Ductile Iron And Solid Solution Strengthened Ferritic Ductile Iron, Alejandra I. Almanza
Dissertations, Master's Theses and Master's Reports
Ductile Iron is a material that is constantly evolving. Consequently, the ferrous industry is not only focusing on lightweighting but also on improving the impact strength and fracture toughness of typical ferritic-pearlitic ductile iron grades and solid solution strengthened ferritic ductile irons. Recently, the demand for thin-wall ductile iron and solid solution strengthened ferritic ductile iron grades has increased. The challenges behind the fabrication of these two ductile iron materials are the presence of carbides and the embrittlement of ferrite. In response, research has been focused on looking at alternative methods that can mitigate carbide formation in thin sections and …
Influence Of Rapid Solidification And Wrought Processing On Precipitation Strengthening And Deformation Mechanisms In Al-Sc-Zr Alloys,
2020
Michigan Technological University
Influence Of Rapid Solidification And Wrought Processing On Precipitation Strengthening And Deformation Mechanisms In Al-Sc-Zr Alloys, Yang Yang
Dissertations, Master's Theses and Master's Reports
Al-Sc-Zr alloys have drawn increasing attention in the last several decades due to their strengthening and coarsening resistance. In this study, solute concentrations of Sc and Zr were increased beyond their equilibrium solubilities without primary precipitate formation using melt-spinning. The melt-spun ribbon was metallurgically bonded into bulk shape using extrusion. With the proper aging treatment, the mechanical properties of the supersaturated melt-spun ribbon and extruded rod were found to be significantly higher than a baseline dilute alloy. Increased mechanical properties include microhardness, tensile strength at ambient-temperature, and compressive strength and threshold stress at and elevated-temperature. These increases were related to …
The Study Of Chemical Induced Polyolefin-Based Ion Exchange Membrane For Electrodialysis Application,
2020
Michigan Technological University
The Study Of Chemical Induced Polyolefin-Based Ion Exchange Membrane For Electrodialysis Application, Di Huang
Dissertations, Master's Theses and Master's Reports
High-performance ion exchange membranes with high ion exchange capacity (IEC), excellent mechanical properties, lower membrane resistance and superior ions conductivity were developed with chemical-induced polymerization in this work. Through a series of synthesizing experiments, structure characterization and properties testing for polyolefin-based cation exchange membrane (CEM) and anion exchange membrane (AEM), LDPE proved to be an optimized backbone material. The CEM with 57.5% styrene, 38.4% LDPE, 3% crosslinking degree and 1% initiator addition yield the highest IEC value (1.72 mol/g) and moderate burst strength. The 10% addition of styrene was found to enhance IEC of 57% to AEM. However, continually increase …
Microstructure And Mechanical Behavior Of Metastable Beta Type Titanium Alloys,
2020
Edith Cowan University
Microstructure And Mechanical Behavior Of Metastable Beta Type Titanium Alloys, Chirag Dhirajlal Rabadia
Theses: Doctorates and Masters
Current biomaterials such as stainless steel, Co-Cr alloys, commercially pure titanium and Ti-6Al- 4V either possess poor mechanical compatibility and/or produce toxic effects in the human body after several years of usage. Consequently, there is an enormous demand for long-lasting biomaterials which provide a better combination of mechanical, corrosion and biological properties. In addition to this, alloys used in high-strength applications possess either high-strength or large plasticity. However, a high-strength alloy should possess a better blend of both strength and plasticity when used in high-strength applications. Metastable β-titanium alloys are the best suited alloys for biomedical and high-strength applications because …
Investigation On The Mechanical Properties And Microstructure Analysis Of Micro-Resistance Spot Welding Between Stainless Steel 316l And Tl-6al-4v,
2020
Universiti Malaya
Investigation On The Mechanical Properties And Microstructure Analysis Of Micro-Resistance Spot Welding Between Stainless Steel 316l And Tl-6al-4v, Mohd Mansor Muhammad Safwan
Student Works (2020-2029)
In this study, ASS 316L and Ti-6Al-4V were welded together by micro-resistance spot welding (μRSW) at different combinations of welding parameters using specifically design electrode geometry in order to acquire the optimal combination of welding parameters. The welded joint were subjected to tensile shear strength test to determine the influence of welding current, welding time, welding force and different design of elctrode tip on the mechanical properties and the strength of the welded joint. The experiment was conducted by using full factorial design of experiment (DoE) with L27 orthogonal array and utilizing the analysis of variance (ANOVA) to obtain the …
Morphology Controlled Preparations And Electrochemical Properties Of Znco2O4 Electrode Materials For Supercapacitors,
2019
School of Materials Science and Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003, Jiangsu, China;
Morphology Controlled Preparations And Electrochemical Properties Of Znco2O4 Electrode Materials For Supercapacitors, Yue-Shen Zhou, Meng Li, Shuang Wu, Zhao-Lei Li, Yan-Min Gao
Journal of Electrochemistry
In this work, hydrothermal reaction and high temperature were used to grow ZnCo2O4 active materials on Ni foam. The crystal stuctures and surface morphlogies of four samples were investigated by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The electrochemical performances were characterized by cyclic voltammetry (CV), galvanostatic charge/discharge (GCD) testing and electrochemical impedance spectroscopy (EIS) on an electrochemical station. It can be seen that active materials tended to form denser stuctures with an increasing amount of NH4F in the solution system and four different morphologies of ZnCo2 …
Electrochemical Behaviors Of Azopurine On Gold Electrodes,
2019
Department of Chemistry,College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, Fujian, China;
Electrochemical Behaviors Of Azopurine On Gold Electrodes, Ming-Xue Li, Hang Shi, Jia Liu, Meng Zhang, Jian-Zhang Zhou, De-Yin Wu, Zhong-Qun Tian
Journal of Electrochemistry
In this paper, we studied the electrochemical behaviors of azopurine on polished gold electrodes with cyclic voltammetry (CV). On the basis of analyzing scan rate and peak current, it was supposed that the redox process belonged to a reversible process controlled by adsorption in 0.2 mol·L-1 PBS (pH = 4.0 ~ 10.0) solutions. The potentials of redox peaks moved more negatively with increasing pH value. This proved that the H+ proton has participcted in the electrochemical reaction. The further data analysis and the calculation of surface adsorption excess demonstrated that the reaction was a two-proton and two-electron process. …
