Materials Science and Engineering Commons^™

Multi-Scale Computational Modeling Of Metal/Ceramic Interfaces, Abu Shama Mohammad Miraz

Master's Theses

Multi-scale atomistic calculations were carried out to understand the interfacial features that dictate the mechanical integrity of the metal/ceramic nanolaminates. As such, first principles density functional theory (DFT) calculations were performed to understand the electronic and atomistic factors governing adhesion and resistance to shear for simple metal/ceramic interfaces, whereas molecular dynamics (MD) simulations were performed to observe the impact of interfacial structures, such as misfit dislocation network geometries and orientation relationships, on interfacial mechanical properties.

For the DFT investigation, we choose metals with different crystal structures, namely - Cu (fcc), Cr (bcc) and Ti (hcp) along with a variety of …

Atomic Oxygen Resistant Low Earth Orbit Stable Polymer Matrix Composites Employing Phenylphosphine Oxide Epoxy-Amines, Witold Fuchs

Dissertations

Atomic oxygen (AO) attacks polymer matrix composites (PMC’s) on the surfaces of spacecraft in low earth orbit (LEO) and threatens safe spacecraft operation and service life. Incorporating phenylphosphine oxide (PPO) groups into polymer chains offers a self-regenerating method of protection from AO but remains poorly understood. Herein, epoxies containing PPO groups were synthesized with increasing concentrations of phosphorus [P] from 0 to 8 wt % to investigate their AO resistance. Measurements confirmed the exposure of these materials to AO produces a passivation phosphate (POx) layer on the surface of the sample and the efficacy of the resultant layer was directly …

Voltage-Controlled Magnetic Anisotropy In Antiferromagnetic Mgo-Capped Mnpt Films, P. H. Chang, Wuzhang Fang, T. Ozaki, Kirill Belashchenko

Kirill Belashchenko Publications

The magnetic anisotropy in MgO-capped MnPt films and its voltage control are studied using first-principles calculations. Sharp variation of the magnetic anisotropy with film thickness, especially in the Pt-terminated film, suggests that it may be widely tuned by adjusting the film thickness. In thick films the linear voltage control coefficient is as large as 1.5 and -0.6 pJ/Vm for Pt-terminated and Mn-terminated interfaces, respectively. The combination of a widely tunable magnetic anisotropy energy and a large voltage-control coefficient suggest that MgO-capped MnPt films can serve as a versatile platform for magnetic memory and antiferromagnonic applications.

Design And Fabrication Of A Microstrip Bandpass Filter In Ltcc, Allison Rucker

Electrical Engineering Undergraduate Honors Theses

The goal of the project was to design and fabricate a bandpass filter with a center frequency of 25GHz with a 2GHz bandwidth. The first step was to do the calculation to design a bandpass filter to meet these specifications along with the properties of the Dupont^TM GreenTape^TM 9K7. HFSS was then used to verify the results from the initial calculations. There was a significant error between the two results, so more tweaking was done to the calculations to get a better center frequency. After a final design was decided, the fabrication process started. Low-Temperature Co-Fired Ceramics (LLTC) …

An Investigation Of Testing Parameters On The Frictional Properties Of Patterned Core-Shell Nanostructures, Colin Phelan

Graduate Theses and Dissertations

Friction tests are a beneficial means to analyze the tribological characteristics and advantages of materials and textured surfaces. However, the selected test parameters can significantly influence the results. This work explores the significance of the friction testing parameters on the frictional performances of core-shell nanostructure-textured surfaces (CSNTSs). Several applied normal loads (10 μN, 100 μN, and 500 μN) and diamond counterface indenter tip radii (1 μm, 5 μm, and 20 μm) were selected for the testing of Al/diamond-like-carbon (DLC) and Al/amorphous silicon (a-Si) CSNTSs. The measured friction values of the CSNTSs were then compared to a matching Al/DLC film and …

A 3d Sers Device For Highly Sensitive Detection Of Organic Chemicals In Liquid, Sankgeeth Vennila Sigamani

Material Science and Engineering Theses - Archive

Detection of organic chemicals in liquid medium have been gaining utmost attention in recent times. Real time detection and monitoring of a variety of environmental pollutants, explosive materials, chemical agents, and pharmaceutical drugs in liquid medium are of great need in today’s technological advancements. While there are several scattering, emission and spectroscopy techniques in use, Raman spectroscopy is attractive because of its molecular specificity i.e., each molecule has a Raman fingerprint. Raman spectroscopy utilizes the inelastic portion of the scattered wave for detection. But since intensity of inelastic scattering (Raman scattering) is very low, compared to the elastic scattering, low …

Characterization Of Asphalt/Recycled Plastic Blends Modified By Exfoliated Clay Nanoplatelets, Kate A. Nguyen

Material Science and Engineering Theses - Archive

There is a renewed interest from federal and state transportation agencies as well as the asphalt industry in developing successful utilization of recycled plastics in asphalt pavements. By incorporating a third material into the asphalt/plastic blend, a stimulation of enhanced compatibility between the waste plastics and asphalt can be observed. In this thesis, the need for increased stability and improved mechanical performance of asphalt blends, at low and high temperatures, are addressed through the use of dispersed/exfoliated organic montmorillonite nanoplatelets a.k.a. nanoclay (NC). Previous studies with non-dispersed NC as a modifier in asphalt (AS) and polyethylene (PE) blends reported the …

Study Of Electromigration Failure Mechanism In Micro Solder Joint, Hossein Madanipour

Material Science and Engineering Dissertations - Archive

The miniaturizing trend for advanced electronic devices has motivated the microelectronic industries to pursue device integration and packaging technology based on the micro-bump solder joint. This type of the joint enables devices with far higher interconnect density and miniaturized form factors which are ideal for mobile applications. The focus of this research is to conduct comprehensive investigation on the electromigration (EM) reliability of micro solder joint. For that purpose, a series of EM tests on micro solder joints under direct current (DC) load was conducted with variation in the contributing factors to EM failure, including solder joint arrangement (change of …

Metal Nanodendrites And Their Applications As 3d Surface Enhanced Scattering (Sers) Substrates, Aseem Athavale

Material Science and Engineering Dissertations - Archive

Ultrasensitive detection of chemicals and biological analytes has been a focus of a lot of studies in the recent years. In this search for the versatile detection technique, Surface Enhanced Raman Spectroscopy (SERS) has proved to be one powerful method. SERS is a powerful vibrational spectroscopy technique that allows for label free ultrasensitive detection. This method utilizes the Localized Surface Plasmon resonance (LSPR) effect of nanoparticles. LSPR effect is profound in noble metals such as silver (Ag) and gold (Au). We have developed a novel SERS substrate using Ag dendrites that can be applied as a ready-to-use device in a …

Multi-Scale Computational Modeling Of Metal/Ceramic Interfaces, Abu Shama Mohammad Miraz

Doctoral Dissertations

Multi-scale atomistic calculations were carried out to understand the interfacial features that dictate the mechanical integrity of the metal/ceramic nanolaminates. As such, first principles density functional theory (DFT) calculations were performed to understand the electronic and atomistic factors governing adhesion and resistance to shear for simple metal/ceramic interfaces, whereas molecular dynamics (MD) simulations were performed to observe the impact of interfacial structures, such as misfit dislocation network geometries and orientation relationships, on interfacial mechanical properties.

For the DFT investigation, we choose metals with different crystal structures, namely - Cu (fcc), Cr (bcc) and Ti (hcp) along with a variety of …

Remote Performance Modulation Of Ultrafiltration Membranes By Magnetically And Thermally Responsive Polymer Chains, Arijit Sengupta, Anh Vu, Xianghong Qian, Sumith R. Wickramasinghe

Chemical Engineering Faculty Publications and Presentations

Ultrafiltration membranes, that respond to an external magnetic field and local temperature have been developed. Surface-initiated activator-generated electron transfer (AGET) atom transfer radical polymerization (ATRP) has been used to graft poly(N-isopropylacrylamide) (PNIPAm) from the surface of 300 kDa regenerated cellulose membranes. The polymerization initiator was selectively attached to the entire membrane surface, only the outer membrane surface or only the inner pore surface. A superparamagnetic nanoparticle was attached to the end of the polymer chain. The DI water flux as well as the flux and rejection of bovine serum albumin were investigated in the absence and presence of a 20 …

Development Of An Intraperitoneal Catheter Placement Device For Use On The Battlefield, Riley Reynolds

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

The objective of this project was to simplify peritoneal cavity access so an Airforce field medic can safely infuse oxygen microbubbles (OMBs) into the intraperitoneal space for the emergency treatment of hypoxia due to lung damage. To solve this problem, we created an intraperitoneal catheter placement device for use on the battlefield. The three common methods and some of the most common devices for peritoneal cavity access were reviewed. Injury frequencies for each of the three methods were analyzed. The results showed that each of the access techniques gives a similar rate of iatrogenic injury.

The battlefield conditions where the …

Biopolymeric Materials For Tissue Regeneration, Cell Manufacturing, And Drug Delivery, David Alfonso Castilla-Casadiego

Graduate Theses and Dissertations

The development of materials for tissue regeneration, cell manufacturing, and drug delivery is possible by the manipulation of polymer properties and the use of three different techniques including layer-by-layer, electrospinning, and molding technique.

By applying the layer-by-layer technique over biomaterials, it is possible to develop polymeric multilayers that promote a more favorable environment for cellular functionality, increasing the possibility of improving their acceptance in the area of implantation. IRVASE demonstrated being a powerful technique that allows for a reliable characterization of the physical-chemical and thermal properties of the fabricated surfaces. This opens the possibility to monitor the design of surfaces …

Characterization Of Gesn Semiconductors For Optoelectronic Devices, Hryhorii Stanchu

Graduate Theses and Dissertations

Germanium-tin alloys with Sn compositions higher than 8 at. % to 10 at. % have recently attracted significant interest as a group IV semiconductor that is ideal for active photonics on a Si substrate. The interest is due to the fact that while at a few percent of Sn, GeSn is an indirect bandgap semiconductor, at about 8 to 10 at. % Sn, GeSn transitions to a direct bandgap semiconductor. This is at first surprising since the solid solubility of Sn in Ge under equilibrium growth conditions is limited to only about 1 at. %. However, under non-equilibrium growth conditions, …

Performance And Economics Of Solar Inverters And Module Level Power Electronics In A 1 Mw Photovoltaic System, Maxwell Criswell

Biological and Agricultural Engineering Undergraduate Honors Theses

Photovoltaic solar panels convert sunlight to electricity in the form of direct current; therefore, a necessary component of every photovoltaic system is an inverter to convert the electricity to usable alternating current. There are various commercially available inverter technologies manufactured today such as microinverters, string inverters, and central inverters, as well as module level power electronic devices such as DC optimizers that are capable of improving system performance in string and central inverter systems. This thesis compares the performance and economics of five different inverter and module level power electronic systems through model simulation using Helioscope software. The five alternatives …

Phase Field Modeling Of Crack Growth In Shape Memory Ceramics, Ehsan Moshkelgosha

Boise State University Theses and Dissertations

Shape memory ceramics (SMCs) are promising candidates for actuators in extreme environments such as high temperature and corrosive applications. Despite outstanding energy dissipation, compared to metallic shape memory materials, SMCs suffer from a sudden brittle fracture. While the interaction of crack propagation and phase transformation in SMCs has been the subject of several experimental and theoretical studies, mainly at the macroscale, the fundamental understanding of the dynamic interaction of crack propagation and martensitic transformation is poorly understood. This dissertation attempts to provide a mathematical model for crack propagation in transformable zirconia to address the shortage of classical methods. This dissertation …

A Hyperelastic Porous Media Framework For Ionic Polymer-Metal Composites And Characterization Of Transduction Phenomena Via Dimensional Analysis And Nonlinear Regression, Zakai J. Olsen

UNLV Theses, Dissertations, Professional Papers, and Capstones

Ionic polymer-metal composites (IPMC) are smart materials that exhibit large deformation in response to small applied voltages, and conversely generate detectable electrical signals in response to mechanical deformations. The study of IPMC materials is a rich field of research, and an interesting intersection of material science, electrochemistry, continuum mechanics, and thermodynamics. Due to their electromechanical and mechanoelectrical transduction capabilities, IPMCs find many applications in robotics, soft robotics, artificial muscles, and biomimetics. This study aims to investigate the dominating physical phenomena that underly the actuation and sensing behavior of IPMC materials. This analysis is made possible by developing a new, hyperelastic …

Mechanical Behavior Of Cyclo-18 On Nickel And Copper Substrates, Reagan Michael Kraft

Mechanical Engineering Undergraduate Honors Theses

Carbyne, an -hybridized allotrope of carbon, has been the subject of many studies recently due to its incredible mechanical properties and small size. More recently, another -hybridized allotrope known as cyclo-18, has gained interest. In this study, computational molecular dynamics will be used to determine the mechanical properties of cyclo-18. Peeling and shearing tests of the molecule will be conducted on nickel and copper, which are respectively active and less-active transition metals. Additionally, a carbyne chain of equal length will undergo the same tests on the copper substrate to compare the mechanical properties of the two. The results conclude that …

Noise Control In Sorting Conveyors, Eyra Herrera

Mechanical Engineering Undergraduate Honors Theses

E-commerce has increased the necessity of effective material handling equipment in warehouses and distribution centers. Sorter conveyors systems facilitate material handling by providing a reliable and automated system to classify and distribute products in a gentle and rapid manner. With the steady increase of speed in sorter conveyors to satisfy today’s industry demand, some systems have started to produce high noise levels that could potentially affect workers’ health. Since decreasing the speed of these conveyors is not a viable option to decrease noise in sorter equipment, industries have opted to find other ways to apply noise control to their equipment. …

Design And Control Of A Peristaltic Pump To Simulate Left Atrial Pressure In A Conductive Silicone Model, Jeremy Collins

Mechanical Engineering Undergraduate Honors Theses

According to the CDC, atrial fibrillation is responsible for more than 454,000 hospitalizations and approximately 158,000 deaths per year. A common treatment for atrial fibrillation is catheter ablation, a process in which a long flexible tube is guided through the femoral artery and to the source of arrhythmia in the heart, where it measures the electrical potential at various locations and converts problematic heart tissue to scar tissue via ablation. This paper details the design and control of a low-cost ($400) peristaltic pump system using repetitive control to replicate blood pressure in the left atrium in a conductive silicone model …