Materials Science and Engineering Commons^™

Anaerobic Reductive Bioleaching Of Manganese Ores, Neha Sharma

Dissertations, Master's Theses and Master's Reports

Manganese extraction by biological methods is a green and economical way to produce manganese from low as well as high grade manganese ores. This is especially important for US ores, which are primarily either small in extent, low-grade with a high iron content, or both. They are therefore not suitable for conventional mining, which is very capital-intensive and requires a large up-front investment and are therefore imported at high costs. The goal is therefore to develop a process that can be applied at small scales, with minimal startup costs, and low equipment and labor requirements. It is also critical to …

Economic Profitability Of Sustainable Buildings Industry, Mohanad Ibrahim Altuma, Hanadi Abdulridha Lateef, Ayad Abdulkhaleq Al-Yousuf

Al-Esraa University College Journal for Engineering Sciences

The increasing global awareness of the Earth's deteriorating condition and the unpredictable effects of climate change has given rise to worldwide phenomena that impact several elements like the economy, agricultural security, water availability, and energy supplies. Buildings contribute significantly to the generation of greenhouse gases, as well as the disposal of pollutants and energy consumption. Therefore, they play a crucial role in addressing environmental issues.

Although sustainable buildings are widely acknowledged as a potential advancement, professionals in the property market still believe that the upfront costs of creating sustainable buildings are significantly higher than those of conventional buildings. This view …

Designing A Visual Control Framework Based On Feature Point Analysis To Guide Robots In Uncharted Areas, Isam Sadiq Rasham Al-Ghadhbawi

Al-Esraa University College Journal for Engineering Sciences

Image processing may be made more accurate and efficient with the use of optical processing technologies. In order to make better design judgments early in the package design process, visual packaging art simulation aims to swiftly develop realistic packaging effects. Conventional simulation techniques frequently yield findings that are neither realistic or detailed, and they also take a lot of time and human resources. Optical processing-based machine vision technology can fully utilize computer vision and image processing techniques to simulate package designs accurately and efficiently. This research proposes a foundation for machine vision technologies based on image optical processing. Real package …

Machine-Learning-Assisted Design Of Deep Eutectic Solvents Based On Uncovered Hydrogen Bond Patterns, Usman Lame Abbas, Yuxuan Zhang, Joseph Tapia, Md Selim, Jin Chen, Jian Shi, Qing Shao

Markey Cancer Center Faculty Publications

Non-ionic deep eutectic solvents (DESs) are non-ionic designer solvents with various applications in catalysis, extraction, carbon capture, and pharmaceuticals. However, discovering new DES candidates is challenging due to a lack of efficient tools that accurately predict DES formation. The search for DES relies heavily on intuition or trial-and-error processes, leading to low success rates or missed opportuni- ties. Recognizing that hydrogen bonds (HBs) play a central role in DES formation, we aim to identify HB features that distinguish DES from non-DES systems and use them to develop machine learning (ML) models to discover new DES systems. We first analyze the …

Effects Of Additions On The Microstructure, Macrostructure, And Mechanical Properties Of Gray Iron, Evan J. Carter

College of Graduate Studies: Theses & Dissertations

The iron matrix is a major component of the gray iron (GI) microstructure, which is the transformation product of austenite during solidification. It is generally accepted that the structure of the austenite will impact the final grain structure and thus the properties of GI. Refinement of the austenite grain structure has the potential to increase the strength of GI. Knowledge of controlling austenite grain size with common alloy additions in GI is very limited and is investigated in this research. Utilizing the DAAS heat treatment process, the austenite grain boundaries can be retained and observed directly. The observations were correlated …

Investigation Of Mechanically Fatigue Low-Frequency Energy Harvesting Effects On Isotropic Materials, Daniel J. Meade

College of Graduate Studies: Theses & Dissertations

This research project reports an exploratory investigation of energy harvesting effect on isotropic material that goes through low frequency mechanical fatigue. Energy harvesting is a growing field of study that can recycle ambient energy back into a system that would otherwise be lost. This is a significantly useful method for the ongoing energy crisis and provides an alternate route to design and upgrade systems to be more efficient and last longer than current system designs. However, it is time to investigate if there is any effect vibration-based energy harvesting has on the structure from which energy is being harvested. To …

Natural Convection Heat Transfer Characteristics Of Sierpinski Carpet Fractal Fins In Horizontal And Vertical Orientations, Ayomide Ayoola

College of Graduate Studies: Theses & Dissertations

This study investigates the thermal performance of fins with perforations inspired by the Sierpinski carpet fractal pattern under natural convection conditions in both vertical and horizontal orientations. The objective is to analyze the effects of fractal iteration levels on three primary performance metrics: efficiency, effectiveness, and effectiveness per unit mass. Experimental evaluations were conducted for fractal fins from iterations 0 through 4, utilizing aluminum material, with each fin heated to controlled conditions. The results reveal that efficiency generally decreases with higher fractal iterations, reflecting increased thermal resistance associated with greater porosity and complex geometry. However, effectiveness per unit mass improves …

A Precision-Controlled Investigation Into The Fundamentals Which Drive The Incredible Superhydrophobic Properties Of Soot, Ashton Bressler

Theses and Dissertations

A PRECISION-CONTROLLED INVESTIGATION INTO THE FUNDAMENTALS WHICH DRIVE THE INCREDIBLE SUPERHYDROPHOBIC PROPERTIES OF SOOT

By Ashton Bressler

A thesis submitted as a partial fulfilment of the Virginia Commonwealth University requirements for a Masters of Science at Virginia Commonwealth University.

Virginia Commonwealth University, 2024.

This thesis investigates a precision controlled superhydrophobic soot surface, composed of semi-rigid linked chains of spheres, with a radii of roughly 14um. These spheres have exceptionally useful hydrophobic properties due to; their large surface area, their large triple phase line length, their low area fraction of solid-liquid interface, their ability to deform, and their strength from both …

Extrusion-Based Additive Manufacturing Of Magnetic Heat Exchange Structures For Caloric Applications, Vaibhav Sharma

Theses and Dissertations

Currently, the commercial building sector accounts for 18% of total U.S. end-use energy consumption, of which almost a third was from on-site combustion of fossil fuels for space and water heating. Magnetic heat pumping (MHP) technology is an energy-efficient, sustainable, environmentally-friendly alternative to conventional vapor-compression cooling technology. Several MHP designs today are predicted to be highly energy efficient, on condition that suitable working materials can be developed. This materials challenge has proven to be daunting due to issues associated with intricate synthesis/post-processing protocols and complications related to shaping the mostly brittle magnetocaloric alloys into thin-walled channeled regenerator structures to facilitate …

Advanced Synthesis And Rational Design Of Support Structures For Nobel Metal Heterogeneous Catalysis: Towards Enhanced Activity And Continuous Processes, Brian R. Clark

Theses and Dissertations

The field of catalysis has a wide-ranging impact. Our group has identified the constant need for improved catalytic activity in high-impact applications such as hydrosilylation and cross-coupling reactions. For these reactions, precious metal catalysts often exhibit markedly better performance than their counterparts, but they can be a significant process cost that decreases overall economic efficiencies. To address this challenge, we explored support structures that can enhance catalytic activity at low metal loadings and improve precious metal recovery through simple filtration. We found that a platinum on graphene nanoplatelet catalyst (PtGNP) synthesized via strong electrostatic adsorption with microwave irradiation (SEA-MW) exhibits …

Change Of Metal Oxidation State At High Temperature, Impact Of Temperature And Reactive Gases, Yegor Nikitin

Dissertations and Theses

The fundamental understanding of gas-solid reactions enables a wide range of applications to be developed and improved. Specifically, the use of metal-based materials is critical to ensuring robust, safe, and long-term operations. For example, in power systems where boilers are used to generate steam for heat or electricity generation the use of stainless metal alloys is critical to allow high quality steam to be produced in a very harsh environment. Alternatively, in catalysis, the use of metal doped heterogeneous catalysts are essential in achieving selectivity and conversion performance for chemical synthesis to emissions abatement. Typically, these metal alloys must withstand …

The Effect Of Nanoconfined Liquid Properties On The Water-Responsive Behavior Of Bacterial Cell Walls, Seungri Kim

Dissertations and Theses

Water-responsive (WR) materials have the ability to mechanically swell and shrink in response to changes in relative humidity (RH). These WR materials are used by many biological systems to perform essential tasks; for example, pinecones use WR materials to release their seeds in dry environments, and wheat awns open and close to propel seeds into the soil, driven by daily RH changes. The WR actuation of some biomaterials is extremely powerful, for example Bacillus subtilis cell walls display record-high actuation energy and power densities of 72 MJ m^-3 and 9.1 MW m^-3, surpassing those of all existing …

Effect Of Annealing On Photoluminescence From Defects In Gan, Oleksandr Andrieiev

Theses and Dissertations

Annealing is a critical process in modern GaN technology, essential for achieving p-type conductivity by activating the Mg_Ga acceptor, as first demonstrated by Shuji Nakamura in the early 1990s. Despite the omnipresence of hydrogen as an impurity in GaN crystals, the precise mechanisms governing hydrogen diffusion and acceptor passivation remain only partially understood. The presented research investigates the effects of annealing-induced activation and hydrogen passivation on C and Be acceptors in GaN grown by MOCVD, HVPE, and MBE methods. We explored these effects by using several annealing techniques, gas compositions, and thermal regimes. A transient behavior between the C …

Thermomechanical Process Simulation And Quantification Of Nanoscale Precipitation Influencing Ductility And Strength During Alloy Processing, Alyssa Stubbers

Theses and Dissertations--Chemical and Materials Engineering

Experimental process simulation and quantification of microstructure development during processing are challenging due to limitations with machinery temperature capability, inadequate resolution and sampling volume of currently available characterization techniques, and difficulty characterizing material microstructures as close to processing-relevant conditions as possible. This dissertation addresses how process simulation can be performed using Gleeble thermomechanical technologies and how microstructure development during these processing simulations can be quantified both in-situ and ex-situ.

The first portion of this dissertation demonstrates how Gleeble technologies can be applied to simulate complex material processing conditions in order to produce process-property profiles that can be used to inform …

Faceting Of Tungsten Via Environmental Control Of Temperature, Pressure And Chemistry, And Evolution Of Thermionic Cathode Materials, Huanhuan Bai

Theses and Dissertations--Chemical and Materials Engineering

Scandate cathode presents a great potential of being used as electron emitters in vacuum electron device due to its excellent emission performance. However, it is burdened by several issues, including poor emission uniformity, inadequate reproducibility, and limited lifetime, which have impeded its further industrial application. Therefore, extensive efforts and studies need to be conducted to obtain a more comprehensive understanding of scandate cathode.

W particles, as the base material, play a fundamental role in scandate cathode. Most recent experimental research has reported that the highly faceted crystallography of W grains contributes to the properties of scandate cathode. In order to …

Experimental Characterization And Quantification Of Deformation Behavior In A Porous Carbon Fiber Network, Robert N Quammen

Theses and Dissertations--Chemical and Materials Engineering

Due to their wide range of attractive functional properties (such as low thermal conductivity and low density) porous materials are utilized in a variety of applications. In order to characterize these properties and others, the intrinsically heterogeneous microstructures of these materials need to be taken into account. These microstructures result in interactions across multiple length scales spanning several orders of magnitude. This makes the creation of robust computational models and straight-forward predictions of mechanical properties difficult for porous materials. With this in mind, this dissertation aims to provide experimental mechanical and deformation information spanning the length scales of interest for …

Novel Precursors For Carbon Fiber Prepared By Direct Carbonization, Leah Noble

Theses and Dissertations--Chemical and Materials Engineering

For decades carbon fiber-based composites have been most heavily employed in lightweight, structural applications where low density and high strength are necessary, most notably within the aerospace industry. However, the advancement of carbon fiber into a wider array of industries has largely been limited by the high financial and energetic costs associated with its manufacture. Moreover, with an increasing societal emphasis on sustainability, there is an ever-growing desire for low-energy carbon fiber production pathways. One such pathway is the conversion of precursor fiber to carbon fiber by direct carbonization, wherein the energy-intensive, pre-carbonization stabilization step is omitted from the carbonization …

Production Of Glass-To-Metal Seals Using Additive Manufacturing Techniques, Aaron Read

Masters Theses

"Glass-to-metal (GtM) seals are hermetic barriers between glass and metal components, often used in the electronic and vacuum industries. Creating the seals traditionally requires heating all the components to the glass melting temperature, where the glass will flow and bond to the metal. Due to the manufacturing constraints of the individual components and sealing conditions there are geometric and material restrictions. Additive manufacturing techniques were used to make GtM seals to reduce these restrictions.

Hermetic, single pin seals were produced using printed metal shells, by selective laser melting (SLM), and digital light processing (DLP) printed glass preforms. Glass preforms were …

Single-Atom Catalysts For Electrochemical Energy Conversion: Copper Single-Atom Catalyst For Oxygen Reduction Reaction And Quantification Of Site Density By Co Stripping Voltammetry, Dawatage Perera

Theses and Dissertations--Chemistry

Fuel cells are considered a promising technology for achieving cleaner and more sustainable energy production and utilization. However, one of the current major challenges is the economic viability associated with the extensive use of Pt group metal (PGM) catalysts, particularly on the cathode side. Therefore, non-PGM single-atom catalysts (SACs) have received considerable attention as alternatives for PGM catalysts in the oxygen reduction reaction (ORR), which occurs at the cathode of the fuel cell. Among various SAC structures, the non-PGM/nitrogen-doped carbon-based structure (M-N-C) stands out for its excellent ORR performance.

Chapter 2 illustrates the use of copper metal in place of …

Applying Synchrotron Saxs And Xas To Study The Microstructure Of Energy Conversion And Storage Materials, Lingzhe Fang

Graduate Research Theses & Dissertations

The microstructure of energy conversion and storage materials is a key determinant of physical properties and electrochemical performance. Synchrotron X-ray techniques, with their strengths of high flux and exceptional brightness, play an irreplaceable role in understanding nano and sub-nano structures. This helps the study of reaction mechanisms and benefits material design in energy conversion and storage area. Electrifying CO2 transformation using renewable energy offers a carbon-neutral solution to CO2 recycling and fuel generation. Among various feedstocks from the CO2 reduction reaction, CO, HCOOH, and CH4 have approached the performance thresholds for industry implementation. The application of single atom catalysts (SACs) …

Near Infrared Upconversion Nanoparticles Modified With Semiconducting Polymers For Anti-Counterfeiting, Abraham Chibuikem Ikeji

Dissertations and Theses

Lanthanide doped up-conversion nanoparticles (UCNPs) are excellent luminescent materials due to their ability to perform photon up-conversion from low energy to high energy using their triplet energy metastable states and because of their long-lived excited state. These properties enable multiple applications with the near infrared upconversion emission. They have been incorporated in developing technologies to help curb counterfeiting activities and other areas of research. However, they still have some limitations such as the hydrophobic nature of the UCNPs, and the absence of functional groups that can also help impact other desired features. Thus, in this work we have coated up-conversion …

Corrosion Behavior Of Ysz And Ysz/Nico Coatings On Inconel 625 Exposed Alkali Chlorides, Resetiana Dwi Desiati, Eni Sugiarti, Bambang Hermanto, Gerald Ensang Timuda, Hubby Izzuddin, Fraya Aulia Salsabilla, Anawati Anawati

Journal of Metals, Materials and Minerals

Alkali chloride attack on boiler pipe walls is considered the main problem of corrosion in the waste-to-energy (WTE) industry, even though uses superalloy. Electrophoretic deposited (EPD) yttria-stabilized zirconia (YSZ) coating is carried out to protect the Inconel 625 substrate. YSZ is deposited directly both on the Inconel 625 substrate and NiCo-Inconel 625. Corrosion resistance was conducted using the 3.5% NaCl electrochemical test and the hot salt corrosion test at 600°C in alkaline salt media such as NaCl, KCl, and CaCl2. The potentiodynamic polarization curve shows that the YSZ coating deposited on the substrate (single-layer) has a corrosion rate of 0.065 …

Study Of Titanium Alloy Ti–Al–Zr–Nb–V During Heating Under Deformation And Its Phase Transformation Features, Aidar Kenzhegulov, Axaule Mamaeva, Aleksander Panichkin, Akerke Imbarova, Balzhan Kshibekova, Rashida Aubakirova, Nazgul Toiynbaeva

Journal of Metals, Materials and Minerals

An alloy based on Ti–Al–Zr–Nb–V was prepared and its deformation behavior at elevated temperatures was studied. The microstructure and phase of the alloys were characterized by optical microscopy, scanning electron microscopy, thermal analysis, and mechanical testing. The results showed that the Ti–Al–Zr–Nb–V alloy, when stretched, exhibits a superplasticity effect in the range of  975℃ to 1100℃, with an elongation of up to 400%. It was found that superplasticity develops in the temperature region of the α+β→β transition and is accompanied by a change in grain size and redistribution of alloying elements among phases.

One-Pot Microwave-Assisted Approach Of Polydiacetylene/Zinc Oxide Nanocomposite For Reversible Thermochromic, Chanita Khanantong, Thanutpon Srinopkun, Thitirut Boonmak, Jintana Siriboon

Journal of Metals, Materials and Minerals

This study introduces a new technique to fabricate the reversible poly(PCDA/ZnO) nanocomposites thermochromism. Our preparation process is the solution-mixing method, which is supported by microwave synthesis time instead of ultrasonic bath or stirrer. The presence of ethanol molecules in aqueous media in the solution-mixing method induces dipolar polarization. In addition, the presence of Zn2+ leaking out of the ZnO can produce ionic polarization. These factors affect the shape of poly(PCDA/ZnO) nanocomposites based on their thermochromic properties. The optical properties of poly(PCDA/ZnO) nanocomposite were determined through UV-Vis absorption spectroscopy. The morphology of this nanocomposite was examined by scanning electron microscopy, and …

Green Synthesis Of Carbon Dots From Mangosteen Peel For Fluorescent Cancer Cells, Supaluck Amloy, Tanachporn Lukprang, Monthon Lertworapreecha, Pakorn Preechaburana

Journal of Metals, Materials and Minerals

Recently, carbon dots (CDs) have received significant attention owing to their outstanding optical properties, good solubility, and low toxicity. In this research, CDs were synthesized by a hydrothermal method based on an environmentally friendly and straightforward strategy, using only mangosteen peel and deionized water. The synthesized CDs had an average size of 3.09 ± 0.38 nm. The absorbance spectrum peak for the CDs was seen at 282 nm, and the central wavelength of fluorescence emission was observed at 433 nm under an excitation wavelength of 355 nm. An aqueous solution of CDs exhibited bright green fluorescence when observed with the …

Fabrication Of Porous Geopolymers Utilizing Aluminum Wastes As Foaming Agent, Siriwan Chokkha, Jiratchaya Ayawanna, Anurat Poowancum, Thanasak Singlaem, Pusit Mitsomwang

Journal of Metals, Materials and Minerals

Porous geopolymers (PG) are attractive due to their simple fabrication and diverse applications. This work presents a method for fabricating PG by using aluminum salt slag (ASS) as a foaming agent and metakaolin (MK) as the precursor. Sodium silicate (Na2SiO3) and sodium hydroxide (NaOH) are used as alkali activator solutions. The results show that the PG is fabricated by using the sequence mixing method. ASS was milled to a size of 4 µm, then mixed with an NaOH solution for 30 min. After that, MK and Na2SiO3 solution were added. The weight ratio of Na2SiO3/NaOH and solid/liquid was 2.0 and …

Influence Of Annealing Times For W Films On The Structure And Electrochromic Properties Of Anodized Wo3 Films, Watcharaporn Thongjoon, Kamon Aiempanakit, Montri Aiempanakit, Chantana Aiempanakit

Journal of Metals, Materials and Minerals

WO3 films were prepared from annealed W films by anodization and annealing at 450℃ for 1 h. The sputtered W films were annealed before anodization at different times for 0.5 h to 2 h, followed by immediate removal from the furnace (quenching) or slow cooling (cool-down). The WO3 films exhibited a different preferred orientation between the (200) and (222) planes. The morphological structure of the WO3 films depended on the annealing time and cooling features of the W films. The WO3 films for the cool-down condition had smaller grains and more pores than the quenching condition. The WO3 films prepared …

Fabrication And Characterization Of Sb-Doped Mxene Prepared By Hydrothermal Method For Use As A Sensing Electrode For Heavy Metal Detection, Siranaree Phoohadsuan, Thitima Maturos Daniels, Mati Horprathum, Nichaphat Thongsai, Eakkasit Punrat

Journal of Metals, Materials and Minerals

MXene, a two-dimensional material with favorable physicochemical characteristics, has demonstrated outstanding efficiency in a wide range of applications because of their superior properties, such as higher surface area and conductivity, and facile surface modification. In this study, antimony (Sb) doped MXenes were synthesized via a simple hydrothermal method, employing various Sb concentrations ranging from 5%w/w to 25%w/w. The successful preparation of the Sb-doped MXene (Sb@MXene) was confirmed by an X-ray diffraction (XRD) method. Physical morphologies examined through field-emission scanning electron microscopy (FE-SEM) depict the presence of Sb nanoparticles with the size of about 80 nm on the surface and interlayer …

Realizing Fast Plating/Stripping Of High-Performance Zn Metal Anode With A Low Zn Loading, Zhuo Li, Tamene Tadesse Beyene, Kai Zhu, Dianxue Cao

Journal of Metals, Materials and Minerals

Zn metal batteries and capacitors (ZMBs/ZMCs) are gaining significant attention due to their low cost, high safety, and high theoretical capacity. However, the low utilization of Zn metal decreases the coulombic efficiency. Here, we present a novel approach to enhance the conductivity of host materials by utilizing a 3D conductive structural network of copper mesh. The 3D copper mesh serves as a high-conductive matrix and additionally coating it with Zn serves as a Zn source. Finally, a flexible reduced graphene oxide (rGO) was deposited on the Zn-coated copper mesh as an anode protective layer. The conductive copper mesh renders a …

The Effects Of The Crystallinity Index Of Cellulose On The Flexural Properties Of Hybrid-Cellulose Epoxy Composites, Nathawat Poopakdee, Warut Thammawichai

Journal of Metals, Materials and Minerals

This work investigated the effects of the crystallinity index (CI) of cellulose on the flexural properties of hybrid-cellulose epoxy composites. The CI was varied by combining cellulose microfibrils (CMF) and microcrystalline cellulose (MCC), extracted from coir and eucalyptus, respectively, in various mixing ratios. From the XRD analysis, it was shown that the CI values and the CMF/MCC content follow a parabolic-fitting pattern, reaching a maximum value of 82.06% for the CMF/MCC of 30/70. The composites with cellulose of different CI values were fabricated and the flexural properties were measured. The results showed that the flexural strength increased as the CI …