Materials Science and Engineering Commons^™

Studies In Additive Manufacturing Techniques For Pulsed Fusion Experiments, Michael Canary

Summer Community of Scholars Posters (RCEU and HCR Combined Programs)

No abstract provided.

Application Of Laser Assisted Ultrasonic Nanocrystal Surface Modification On Aluminum And 3d Printed Titanium, Eman Hassan, Thomas Crouse

Williams Honors College, Honors Research Projects

A novel surface treatment, laser assisted ultrasonic nanocrystal surface modification (LA-UNSM), has proved effective in increasing surface hardness, and fatigue life. The objective of this research is to determine the effectiveness of this process on components created with additive manufacturing. To accomplish this, we investigated the effectiveness of LA-UNSM treatment on aluminum, a common 3d printed metal, and the effectiveness of LA-UNSM processing on 3d printed titanium. We first conducted our own literature review to assess the practicality of using this same treatment on aluminum. We then treated traditionally manufactured aluminum at varying levels of laser intensity to determine if …

Jominy Hardenability Tester Redesign, Dennis Kopacz, Shadoe Beatty, Thomas Benenati, Jared Mclean, Matthew Yokosuk

Williams Honors College, Honors Research Projects

Our project is Redesigning a Hardenability Tester. The goal of this project is to figure out how to incorporate an intensive quenching system to the current design from last years group. An intensive quench is a new system that is safer to harden steel and it hardens steel more effectively than other quenching processes. This will be achieved through testing the initial design to make sure it is able to run. After that as a group we will take this system through a design process to introduce a safe process of intensive quenching to the tester.

Generation Of Excited Species In A Streamer Discharge, Shirshak K. Dhali

Electrical & Computer Engineering Faculty Publications

At or near atmospheric pressure, most transient discharges, particularly in molecular gases or gas mixture containing molecular gases, result in a space charge dominated transport called a streamer discharge. The excited species generation in such discharges forms the basis for plasma chemistry in most technological applications. In this paper, we simulate the propagation of streamers in atmospheric pressure N₂ to understand the energy partitioning in the formation of various excited species and compare the results to a uniform Townsend discharge. The model is fully two-dimensional with azimuthal symmetry. The results show a significantly larger fraction of the energy goes …

Understanding Flow Characteristics In Metal Additive Manufacturing, Carl R. Hartsfield, Travis E. Shelton, Gregory R. Cobb, Ryan A. Kemnitz, Joseph Weber

Faculty Publications

In fluid flow, the frictional effects from interior surfaces of flow components create pressure loss across the surface. Understanding this inherent pressure loss due to friction and other phenomena is important when designing a flow system. For conventional manufacturing, friction loss has been empirically studied and is well known in the engineering community. However, newer manufacturing techniques, such as laser powder bed fusion (LPBF), an additive manufacturing technique, need to be understood. The inherent flow conditions resulting from the additive processes were studied. Test samples were printed with the flow path oriented in the vertical direction with different channel diameters …

Microstructural And Chemical Characterization Of A Purple Pigment From A Faiyum Mummy Portrait, Glenn Gates, Yaqiao Wu, Jatuporn Burns, Jennifer Watkins, Darryl P. Butt

Materials Science and Engineering Faculty Publications and Presentations

Results are presented from analyses that were conducted to explain the presence of chromium, detected noninvasively using energy-dispersive X-ray fluorescence (XRF), in the unusually large (2-3mm diameter) rough gem-like purple pigment particles in the paint used for a Faiyum mummy portrait. An approximately 50 μm diameter particle of the chromium-containing purple pigment was extracted from the Portrait of a Bearded Man, dated to Roman Imperial Egypt in the second century, circa 170-180 CE, accession #32.6 in the Walters Art Museum collection. The particle was characterized using energy-dispersive X-ray fluorescence analysis, electron microscopy, diffraction, and atom probe tomography. It is …

Influence Of The Inas Coverage On The Performance Of Submonolayer-Quantum-Dot Infrared Photodetectors Grown With A (2×4) Surface Reconstruction, Ahmad Alzeidan, Tiago F. De Cantalice, Kevin D. Vallejo, Paul J. Simmonds, Alain A. Quivy

Materials Science and Engineering Faculty Publications and Presentations

Two infrared photodetectors based on submonolayer quantum dots, having a different InAs coverage of 35% and 50%, were grown, processed and tested. The detector with the larger coverage yielded a specific detectivity of 1.13×10 ¹¹ cm Hz ^1/2 W ^-1 at 12K, which is among the highest values reported in the literature for that kind of device.

Reclamation Of Fused Silica From Investment Shells Used For Casting Steel, Samuel L. Holt

College of Graduate Studies: Theses & Dissertations

Fused silica is widely used for investment casting shell molds. Fused silica shells are discarded after being used for casting one time. This is due to the transformation of fused silica to beta cristobalite above 1652℉ (900℃). To reduce cost and waste of investment casting foundries, this study is exploring a method to inhibit transformation of fused silica and reclaim it from high temperature investment casting shells. This research has employed firing to minimalize fused silica transformation to cristobalite. The phase transformation is minimalized due to sintering and coarsening of the particles during firing. Coarsening reduces surface area to volume …

Solidification Cracking In Binary Al-Cu Alloys Additively Manufactured Through Laser Powder Bed Fusion, Keegan Muller

Electronic Theses and Dissertations, 2020-2023

Laser Powder Bed Fusion (LPBF) is an additive manufacturing technique with growing relevance in industry. However, alloys with a high susceptibility to micro-cracking during solidification cannot be feasibly manufactured through LPBF, such as in selected high-strength Al-alloys. The cracking susceptibility (CS) of Al-alloys varies with composition, so modeling CS with respect to composition is crucial in designing compatible alloys for LPBF. In a theoretical modeling of solidification cracking based on the Scheil equation, the relative CS is taken as the maximum value of |dT/d(fs^1/2)| when solidification is near completion. However, experimental observations of the crack density in Al-alloys suggest that …

The Critical Role Of Dynamic Surface Tension Of Surfactants On The Impact Dynamics Of Water Droplets, Amir Esmaeili, Reza Mohammadi

Graduate Research Posters

Due to their time-dependent surface tension, the addition of surface-active agents or surfactants to water for specific applications has made controlling the impact dynamics of these droplets a complex phenomenon. This work investigates the influence of the molecular weight, concentration, and ionic nature of the surfactants as well as the substrate surface characteristics on the impact dynamics of surfactant-laden droplets using a high-speed camera at 10000 frames per second. Sodium dodecyl sulfate, hexadecyltrimethylammonium bromide, and n-decanoyl-n-methylglucamine were used as anionic, cationic, and nonionic surfactants, respectively. We used hydrophilic glass slides, hydrophobic polytetrafluoroethylene, and superhydrophobic alkyl ketene dimer (AKD) as substrates. …

(Quinolin-8-Yl) Tin Synthons In Transmetalation Reactions With Transition Metals Yield Multimetallic Organometallic Molecules And Clusters, Arjun Chandra Bhowmick

Dissertations and Theses

Transition metal (Hg, Ag, Pd, Ni, Sn, Cu) complexes and clusters form from the reaction of metal salts and QSnX (Q = quinolin-8-yl; X = Q or Cl) synthons. Our original intent was the use of Q2Hg, Q2Sn, or QSnCl as an ambiphilic ligand; however, we observed an apparent redox-trans metalation reaction in most of the cases. Bimetallic Hg-Ag complexes were prepared using Q2Hg as an ambiphilic ligand. Heterobimetallic (Ni-Sn and Pd-Sn) complexes were obtained from the reaction of NiCl2 (or PdCl2) with in situ generated QSnCl. Geometry and electronic configuration of the complexes were investigated using DFT methods. The …

Experimental Exploration Of Shared Magnetic Phases Between Diverse Systems Of Iron-Pnictide Superconductors, Ryan Scott Stadel

Graduate Research Theses & Dissertations

The exciting field of iron-pnictide superconductors offers unique opportunities for studying the relationship between magnetism and unconventional superconductivity. This is vital to developing an understanding of the microscopic origin of high-temperature superconductivity, which is itself an important step in harnessing such a potentially revolutionary technology.

Polycrystalline and crystalline samples are synthesized over a diverse collection of related iron-pnictide systems including (Ca,Sr,Ba)1-xNaxFe2As2, Ba(Fe1-xCox)2As2 (122s), and LaFeAs1-xPxO, and TbFeAs1-xPxO (1111s). These compounds are characterized through various types of neutron and x-ray diffraction on multiple instruments, as well as muon spin resonance, and magnetic susceptibility measurements.

A thorough investigation into the conditions under …

In Depth Characterisation Of The Biomolecular Coronas Of Polymer Coated Inorganic Nanoparticles With Differential Centrifugal Sedimentation, André Perez-Potti, Hender Lopez, Beatriz Pelaz, Abuelmagd Abdelmonem, Mahmoud G. Soliman, Ingmar Schoen, Philip M. Kelly, Kenneth A. Dawson, Wolfgang J. Parak, Zeljka Krpetic, Marco P. Monopoli

Articles

Advances in nanofabrication methods have enabled the tailoring of new strategies towards the controlled production of nanoparticles with attractive applications in healthcare. In many cases, their characterisation remains a big challenge, particularly for small-sized functional nanoparticles of 5 nm diameter or smaller, where current particle sizing techniques struggle to provide the required sensitivity and accuracy. There is a clear need for the development of new reliable characterisation approaches for the physico-chemical characterisation of nanoparticles with significant accuracy, particularly for the analysis of the particles in the presence of complex biological fluids. Herein, we show that the Differential Centrifugal Sedimentation can …

Morphology Control Of One-Dimensional Gallium Nitride Nanostructures By Modulating The Crystallinity Of Sacrificial Gallium Oxide Templates, Yun Taek Ko, Mijeong Park, Jingyeong Park, Jaeyun Moon, Yong Ho Choa, Young In Lee

Mechanical Engineering Faculty Research

In this study, we demonstrated a method of controllably synthesizing one-dimensional nanostructures having a dense or a hollow structure using fibrous sacrificial templates with tunable crystallinity. The fibrous ga2o3 templates were prepared by calcining the polymer/gallium precursor nanofiber synthesized by an electrospinning process, and their crystallinity was varied by controlling the calcination temperature from 500oC to 900oC. gaN nanostructures were transformed by nitriding the ga2o3 nanofibers using NH3 gas. All of the transformed gaN nanostructures maintained a one-dimensional structure well and exhibited a diameter of about 50 nm, but their morphology was clearly distinguished according to the crystallinity of the …

Direct Energy Deposition Of Mo Powder Prepared By Electrode Induction Melting Gas Atomization, Goo Won Roh, Eun Soo Park, Jaeyun Moon, Hojun Lee, Jongmin Byun

Mechanical Engineering Faculty Research

Molybdenum (Mo) is used to form a barrier layer for metal wiring in displays or semiconductor devices. Recently, researches have been continuously attempted to fabricate Mo sputtering targets through additive manufacturing. in this study, spherical Mo powders with an average particle size of about 37 um were manufactured by electrode induction melting gas atomization. Subsequently, Mo layer with a thickness of 0.25 mm was formed by direct energy deposition in which the scan speed was set as a variable. According to the change of the scan speed, pores or cracks were found in the Mo deposition layer. Mo layer deposited …

Valorization Of Xylan In Agroforestry Waste Streams, Harrison Appiah

Graduate Theses, Dissertations, and Problem Reports (ETD)

Valorization of Xylan in Agroforestry Waste Streams.

Harrison Appiah

Microwave-assisted deep eutectic solvent and gamma-valerolactone metallic chloride catalyzed conversion of xylan to furfural were investigated using a 2x3 factorial experimental design at two levels of percent microwave power, reaction time, and catalyst concentration. The levels of each factor studied were (20%, 60% microwave power, 2, 4 minutes, and 10, 20mg) respectively. The effect of three metallic chloride catalysts (LiCl, FeCl3.6H20, CuCl2) on the conversion of xylan to furfural was also investigated. The gamma-valerolactone-ferric chloride sent system exhibited the highest mean yield of furfural (56.50%). The next highest furfural yield of …

Timber Bridge Pile Splicing With Fiber Reinforced Polymer Wraps, Drew L. Damich

Graduate Theses, Dissertations, and Problem Reports (ETD)

Timber pile repair using splicing is widely used but little research has been done to determine their strength capacity after repair using this method. Current timber pile splicing mechanisms utilize various steel or wooden components. Fiber Reinforced Polymer (FRP) wraps can be utilized as replacement to conventional materials in splicing of timber piles. This study evaluated the strength capacities of traditional splicing mechanisms in relation to FRP wrap splice mechanisms. Traditional splicing mechanisms consisted of flat steel plate, C-channel steel plate, and wooden plate splices. The FRP wrap splice consisted of unidirectional glass/epoxy composite with three layers of fabric as …

Recovery Of Phosphorus From Florida Phosphatic Waste Clay, Amir Eskanlou

Graduate Theses, Dissertations, and Problem Reports (ETD)

This MS thesis examines the recovery of phosphorus (P) from Florida waste clay (WC). A comprehensive literature review revealed that: (i)-The most important values being lost to WC are P and rare earth elements (REEs). For the recovery of these values from WC, two crucial attempts are the removal of extremely fine-sized clays, followed by the recovery of phosphate content, which can pave the path for the recovery of REEs; (ii)-Any scientific/ technological solution should, at the same time, be economically and environmentally attractive to the industry. As such, moving from mostly chemical separation processes to the primarily physical/ physicochemical …

Improving Performance And Durability Of Intermediate Temperature Proton‐Conducting Solid Oxide Electrolysis Cells Via Materials Design And Catalyst Surface Engineering, Hanchen Tian

Graduate Theses, Dissertations, and Problem Reports (ETD)

Solid oxide steam electrolysis cell, a promising electrical-chemical conversion device for the next generation efficient hydrogen production and energy storage, has been actively studied because of their high energy conversion efficiencies and prospective applications as electrochemical reactors. After decades of research on protonic ceramic materials, remarkable advances have been made in the protonic ceramic electrochemical cells (PCECs) air electrode and electrolyte. However, the existing air electrodes are far from satisfying the requirements of practical applications, a series of issues, including the lack of active and durable electrodes, greatly limit the commercialization. To date, the systematic development of triple conducting catalysts …

Combined Puncture And Cutting Of Soft-Coated Fabrics By A Pointed Blade: Energy, Force, And Stress Failure Criteria, Ennouri Triki, Chantal Gauvin

Études primaires

Soft elastomer-coated fabrics are widely used in engineering and protective applications. Puncture cutting by sharp-tipped objects is one of the most common failure modes of protective gloves made of coated fabrics. In order to investigate the puncture-cutting process of soft elastomer-coated fabrics, we studied the mechanisms and mechanics of pointed-blade insertion into specimens cut out from four protective gloves. Experimental and analytical analyses showed that total energy and critical puncture-cutting force calculated analytically are both able to predict the puncture-cutting resistance of soft elastomer-coated fabrics measured experimentally. Total energy is obtained from the relationship between the puncture-cutting work and the …

Increasing The Seebeck Coefficient Of Thermoelectric Calcium Cobaltite Ceramics Through Incorporation Of Rare-Earth Elements, Andre Fabian Fernandes

Graduate Theses, Dissertations, and Problem Reports (ETD)

The demand for alternative sources of energy continues to grow, so it is essential to look for alternatives that are environmentally sustainable to minimize the environmental impact of energy generation. Projections suggest that renewables have the potential to make up over fifty percent of power generation by 2035. Studies have shown that in 2020 more than 62% of the energy produced in the US was lost, with most of this energy being in the form of waste heat. Waste heat can be utilized to improve the efficiency of power production or even power other devices. This waste heat can be …

Fabrication Of Nanoporous Materials For Applications Under Extreme Environments, Maria Kosmidou

Theses and Dissertations--Chemical and Materials Engineering

The study of nanoporous materials has become a key aspect of nanotechnology due to their high surface-area-to-volume ratio, arising from the small size ligaments and pores that form the structure. Sensing, catalysis, micro-electromechanical systems (MEMS), medical applications, and materials for radiation environments are some of the applications for which nanoporous materials are considered great candidates. This work, performed at the Ion Beam Laboratory (IBL) at Sandia National Laboratories (SNL), examines the effect of heavy and light ion irradiation exposure on nanoporous Au. Radiation damage accumulation is observed with real-time recording of the creation, migration, and removal of the radiation-induced defects …

Electrochemical Performance Of Biomass-Derived Activated Carbon Supercapacitor Under Compression, Yulin Zhang

Theses and Dissertations--Chemical and Materials Engineering

Supercapacitors are important energy storage device of high-power density, fast charge/discharge rate, environmental friendliness and long service life. Currently, flexible supercapacitors have attracted widespread interest in academia and industry. Supercapacitors under the action of external force will inevitably cause structural changes, performance degradation and even loss of energy storage and supply functionalities. As the most abundant renewable resource so far, biomass is an important energy source for human survival and development. Most electrode materials for supercapacitors are porous activated carbons, which can be derived from abundant renewable biomass, contributing to the sustainable development of society and environmental protection. This thesis …

The Development Of Structural Hollow Carbon Fibers From A Multifilament Segmented Arc Spinneret: Precursors, Oxidation, And Carbonization, Elizabeth Ashley Morris

Theses and Dissertations--Chemical and Materials Engineering

Carbon fiber is an ideal material for structural applications requiring high strength and stiffness and low weight. Yet it has seen only incremental improvements in properties over the last few decades. Carbon fibers remain limited in attaining their theoretical tensile strength and modulus, largely due to defects in their structure, some of which stem from the fiber production process itself. Through the mitigation of defect formation as well as approaches to decrease fiber linear density, it is hypothesized that carbon fiber with enhanced specific properties, including specific strength and modulus, could be produced which would significantly propel its unique capabilities. …

Anaerobic Reductive Bioleaching Of Manganese Ores, Neha Sharma

Dissertations, Master's Theses and Master's Reports

The increasing demand of manganese in the industries and various hindrances in its production from low grade ores by conventional method has made it imperative for researchers around the world to develop a method of manganese extraction from low grade ores that is both environment friendly and economical. Bioleaching has shown significant potential in manganese extraction and efficiencies of extraction have been found to be 70-98% with the help of various bacteria and fungi.

This study focuses on extraction of manganese with the help of mixed bacterial strains that have been collected from their natural anaerobic environment. The extraction of …

Thermomechanical Mechanisms That Cause Adhesion Of Aluminum High Pressure Die Castings To The Die, Alex Monroe

Dissertations, Master's Theses and Master's Reports

In high pressure die casting (HPDC) of aluminum, cast material adhering to die is a significant defect. Adhesion occurs in two primary ways. The casting may stick preventing its removal from the die. Aluminum can also adhere to the die and buildup in local areas on the die surface with additional casting cycles. This second form of adhesion is called soldering. Lubricant is the best technology to control all forms of adhesion, but it comes at the cost of casting porosity, blisters, reduced die life, and increased die casting machine wear. New strategies to prevent adhesion are desired to eliminate …

Exploring Rapid Solidification And Equal Channel Angular Pressing In The Fabrication Of Mg-Based Alloys For Medical Applications, Emily Tom

Dissertations, Master's Theses and Master's Reports

The development of magnesium bioresorbable implants has become increasingly popular due to the increased need for temporary implants and magnesium’s excellent biocompatibility and suitable elastic modulus. Even though magnesium is an excellent candidate, when alloyed with other metals magnesium’s corrosion rate becomes too rapid for bioresorbable medical applications. The investigation into novel processing techniques to control the formation of precipitates to improve mechanical strength and ductility as well as corrosion rates has become of interest. This work investigates the combination of two nonequilibrium processing techniques, rapid solidification (RS) and equal channel angular pressing (ECAP), and the effects it has on …

Coaxially Electrospun Fibrous Polymer Scaffolds For Tissue Regeneration And Drug Delivery, Matthew Michael Kleszynski

Graduate Research Theses & Dissertations

A biomaterial is a substance that is specifically engineered to take on a role within the body, either alone or in conjunction with other materials, with the purpose of influencing the body. Using Polymers as a biomaterial is an exciting field of study that has the potential to further our abilities to help those in need. Creating composite nanofibrous scaffolds composed of hydrophobic and hydrophilic polymers may outperform structures made of a single polymer in both in vitro and in vivo environments. Hydrophilicity governs the behavior of polymers in the body and has influence over the mechanical properties of the …

Superconducting Cuprates: Synthesis, Characterization And Diffuse Scattering Properties, Bisham Poudel

Graduate Research Theses & Dissertations

Since its discovery more than a century ago, the fascinating phenomenon of superconductivity remains as mysterious as ever with the greatest challenge facing the condensed matter community being the elusive understanding of the microscopic origin leading to its inception. Many outstanding questions remain of which the role played by nematic fluctuations and structural disorder for the stabilization of superconductivity is not well understood. In this respect, superconducting YBa2Cu3O6+x (YBCO)-type cuprates present an ideal framework in which charge doping, structural disorder and various site manipulations can be explored in efforts to address some of these questions. Extensive synthesis and characterization efforts …

Tailoring Thermoresponsive Poly(N-Isopropylacrylamide) Toward Sensing Perfluoroalkyl Acids, Dustin Thomas Savage

Theses and Dissertations--Chemical and Materials Engineering

Widespread distribution of poly- and perfluoroalkyl substances (PFAS) in the environment combined with concerns for their potentially negative health effects has motivated regulators to establish strict standards for their surveillance. The United States Environmental Protection Agency issued a cumulative domestic threshold of 70 ppt for water supplies, and this bar is even lower in some local districts and other countries. Monitoring PFAS consequently requires sensitive analytical equipment to meet regulatory specifications, and liquid chromatography with tandem mass spectroscopy (LC/MS/MS) is the most common technique used to satisfy these requirements. Though extremely sensitive, the instrument is often burdened by pretreatment regimens, …