Materials Science and Engineering Commons^™

Theoretical Analysis Of Experimental Data Of Sodium Diffusion In Oxidized Molybdenum Thin Films, Orlando Ayala, Benjamin Belfore, Tasnuva Ashrafee, John Akwari, Grace Rajan, Shankar Karki, Deewakar Poudel, Sylvain Marsillac

Engineering Technology Faculty Publications

In this work, the diffusion process of sodium (Na) in molybdenum (Mo) thin films while it was deposited on soda lime glass (SLG) was studied. A small amount of oxygen was present in the chamber while the direct-current (DC) magnetron sputtering was used for the deposition. The substrate temperatures were varied to observe its effect. Such molybdenum films, with or without oxidations, are often used in thin film solar cells, either as back contact or as hole transport layers. Secondary ion mass spectrometry (SIMS) was used to quantify the concentration of the species. A grain diffusion mechanistic model incorporating the …

The Investigation Of The Underlying Microstructure Associated With Fracture Features In 6061 Cold Sprayed Aluminum, Justin White

UNF Graduate Theses and Dissertations

Cold gas dynamic spraying commonly known as cold spray is a process currently used for restoration, re-tolerancing, and application of coatings. With additional resources allocated towards the development of a through process model aimed at predicting the properties of bulk material produced via the Cold Spray process, more lab testing and investigation must be done to capture the effects of the varying microstructure in CS materials. The properties of ultra-fine-grained materials are derived from data collected from coarse grained materials and processes that do not accurately capture the effects as elevated strain rates and ultra-fine-grained materials. The lack of property …

Degradation Issues And Stabilization Strategies Of Protonic Ceramic Electrolysis Cells For Steam Electrolysis, Hanrui Su, Yun Hang Hu

Michigan Tech Publications

Protonic ceramic electrolysis cells (PCECs) are attractive electrochemical devices for converting electrical energy to chemicals due to their high conversion efficiency, favorable thermodynamics, fast kinetics, and inexpensive materials. Compared with conventional oxygen ion-conducting solid oxide electrolysis cells, PCECs operate at a lower operating temperature and a favorable operation mode, thus expecting high durability. However, the degradation of PCECs is still significant, hampering their development. In this review, the typical degradations of PCECs are summarized, with emphasis on the chemical stability of the electrolytes and the air electrode materials. Moreover, the degradation mechanism and influencing factors are assessed deeply. Finally, the …

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 …

Valorization Of Xylan In Agroforestry Waste Streams, Harrison Appiah

Graduate Theses, Dissertations, and Problem Reports

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 …

Jcati Pyrolysis System, Jack Dutton

All Undergraduate Projects

The Joint Center for Aerospace Technology Innovation (JCATI) project is designed to recycle carbon fiber pieces for use in manufacturing. Part of the system requires the removal of resin from the carbon fibers to facilitate the recycling of carbon fiber. To accomplish this task the pyrolysis process is implemented using a commercial grade oven with a conveyor system. Argon gas is injected into the shroud and over the oven to purge the interior of oxygen. The conveyor system enables this to be a batch process. A ramp is used to allow simple addition of material to the conveyor system and …

Optimisation Of Retrofit Wall Insulation: An Irish Case Study, Rakshit D. Muddu, D M. Gowda, Anthony James Robinson, Aimee Byrne

Articles

Ireland has one of the highest rates of emissions per capita in the world and its residential sector is responsible for approximately 10% of total national CO2 emissions. Therefore, reducing the CO2 emissions in this sector will play a decisive role in achieving EU targets of reducing emissions by 40% by 2030. To better inform decisions regarding retrofit of the existing building stock, this study proposes Optimum Insulation Thicknesses (OIT) for typical walls in 25 regions in Ireland. The calculation of OIT includes annual heat energy expenditure, CO2 emissions, and material payback period. The approach taken is based on Heating …

Mechanical Properties Of Nanomodified Hybrid Gfrp Composite Materials, Micah Rop Kimutai

Electronic Theses and Dissertations

The mechanical behavior of the nanomodified hybrid epoxy matrix was investigated in glass fiber reinforced plastics (GFRP). In this study, five nanocomposites enriched with as received halloysite, nanomer I.28E, HNT-APTES, and the hybrid combinations of the two HNTs with the nanomer I.28E were successfully fabricated. To evaluate the effects and morphological characteristics of the individual fillers and the hybrid configurations on the epoxy resin matrix, TGA, DSC, and DMA were analyzed. To understand the effect of the five configurations on the neat GFRP laminate, mode I interlaminar fracture toughness, tensile, and vibration properties were investigated. Electron microscopy testing techniques were …

Molecular To Macroscopic Understanding Of Chloroaluminate Anion Intercalation In Rechargeable Aluminum-Graphite Batteries, Jeffrey Xu

Dissertations and Theses

Today’s global energy challenges pose an urgent need to electrify transportation and better store intermittent renewable energy sources (e.g., solar and wind energy). For such large-scale battery applications, aluminum batteries are a promising “beyond lithium-ion” technology due to the high volumetric capacity, earth abundance, low-cost, and inherent safety of aluminum metal. However, there are very few compatible positive electrode materials that exhibit high energy density and cycling stability, in part due to the challenges of electrochemically intercalating highly charged Al³⁺ cations. Recently, graphite has been demonstrated as a promising positive electrode material in non-aqueous rechargeable aluminum batteries, which store …

Development Of An Injectable Methylcellulose Hydrogel System For Nucleus Pulposus Repair And Regeneration, Nada A. Haq-Siddiqi

Dissertations and Theses

Low back pain is the most common cause of disability in the world and is often caused by degeneration or injury of the intervertebral disc (IVD). The IVD is a complex, fibrocartilaginous tissue that allows for the wide range of spinal mobility. Disc degeneration is a progressive condition believed to begin in the central, gelatinous nucleus pulposus (NP) region of the tissue, for which there are few preventative therapies. Current therapeutic strategies include pain management and exercise, or surgical intervention such as spinal fusion, none of which address the underlying cause of degeneration. With an increasingly aging population, the socioeconomic …

Source Data For "End Exclusion Zones In Strongly Stretched, Molten Polymer Brushes Of Arbitrary Shape", Michael S. Dimitriyev, Gregory M. Grason

Data and Datasets

Supplementary code for solving the constraint equations that describe curved polymer brushes. Also contains software for analyzing the resulting solutions.

การเตรียมคอนกรีตมวลเบาและมวลรวมเบาจากขี้เถ้าชีวมวล, อรปิยะ อังอติชาติ

Chulalongkorn University Theses and Dissertations (Chula ETD)

วิทยานิพนธ์ฉบับนี้ทำการศึกษาการเตรียมมวลรวมเบาและคอนกรีตมวลเบาจากเถ้าชีวมวลชนิดต่าง ๆ ได้แก่ เถ้าลอยจากโรงงานกระดาษ (CPFA1 และ CPFA2) เถ้าลอยกะลาและเปลือกมะพร้าว (CFA) เถ้าชานอ้อย (BA1 และ BA2) เถ้าปาล์มน้ำมัน (PA) เถ้าลอยเศษไม้ (WFA) และเถ้าแกลบ (RA) มวลรวมเบาถูกเตรียมขึ้นจากตัวอย่างเถ้าชีวมวลโดยการร่อนคัดขนาดที่ละเอียดกว่าตะแกรงร่อนเบอร์ 100 เมช (150 ไมครอน) ใช้จานปั้นเม็ดด้วยอัตราส่วนเถ้าและปูนซีเมนต์ปอร์ตแลนด์ร้อยละ 90 และ 10 โดยมวล ตามลำดับ มวลรวมที่เตรียมได้มีขนาดเส้นผ่านศูนย์กลางอยู่ในช่วง 4.0 ถึง 16.0 มิลลิเมตร และมีค่าความหนาแน่นรวมระหว่าง 658 ถึง 1,104 กิโลกรัมต่อลูกบาศก์เมตร การดูดซึมน้ำของมวลรวมมีค่าตั้งแต่ร้อยละ 18.46 ถึงร้อยละ 28.99 โดยมวล จากการทดสอบความต้านแรงกดแตกเม็ดเดี่ยวพบว่าเม็ดมวลรวมอายุ 28 วันที่เตรียมขึ้นมีค่าความต้านแรงกดแตกเม็ดเดี่ยวสูงสุดถึง 843.53 นิวตัน และเมื่อพิจารณาเปรียบเทียบกับตัวอย่างควบคุมพบว่าเม็ดมวลรวมจากเถ้า CPFA2 มีค่าความต้านแรงกดแตกที่สูงกว่า ในขณะที่มวลรวมจากเถ้า BA2 และเถ้า WFA มีค่าความต้านแรงกดแตกที่ใกล้เคียงกับเม็ดดินเผาพองตัวที่เป็นวัสดุทางการค้า แสดงให้เห็นถึงความสัมพันธ์ระหว่างสมบัติเชิงกลของเม็ดมวลรวมและค่าดัชนีกำลังของเถ้าที่นำมาเป็นวัตถุดิบในการขึ้นรูป เมื่อนำมวลรวมที่เตรียมได้ไปใช้แทนที่เม็ดดินเผาพองตัวในคอนกรีตพบว่าได้คอนกรีตมวลเบาที่มีความต้านแรงอัดระหว่าง 9.25 ถึง 28.34 เมกะพาสคัล แสดงให้เห็นถึงศักยภาพของการเตรียมเม็ดมวลรวมเบาจากเถ้าชีวมวลด้วยการใช้จานปั้นเม็ดและความเป็นไปได้ในการนำเม็ดมวลรวมเบาดังกล่าวมาแทนที่เม็ดดินเผาพองตัวในคอนกรีตมวลเบาบางส่วนหรือทั้งหมด

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 …

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

Graduate Theses, Dissertations, and Problem Reports

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 …

Metal Supported Solid Oxide Fuel Cell Using Proton Conducting Electrolyte For Direct Ammonia Utilization, Edwin Vega Hiraldo

Graduate Theses, Dissertations, and Problem Reports

Transportation represents about 27% of global warming greenhouse gas emissions nowadays. To reduce these emissions, fuel cell electric vehicles have been poised to be a new trend to provide zero-emission transportation. Among them, solid oxide fuel cells (SOFCs) offer efficient, clean energy, especially when powered by carbon-free fuel, such as ammonia. To enable onboard ammonia-fed SOFCs, a metal-supported, proton-conducting SOFC is investigated in this study. The metal support would provide physical robustness for thermal shock during vehicles’ quick start-up and shutdown, reduce internal temperature gradients due to the greater thermal conductivity of the metal, and enable conventional metal joining for …

Investigation Of Surface Charge Using Faraday Bucket Measurements: Analysis On Electrospun Polyvinylidene Fluoride Fiber Mats, Ryan Kantenwein

Williams Honors College, Honors Research Projects

Piezoelectric polymer materials such as polyvinylidene fluoride exhibit beneficial properties for use in personal protective equipment (PPE) against viral contaminants and other foreign microparticles. The electrospinning process of this material allows for surface charge to develop over a controlled surface area. Kynar 761 at 10 wt% demonstrates increased surface charge after withstanding a flow of aerated NaCl particles from a TSI 8130 instrument. Utilizing voltage measurements from a Faraday bucket, 18 wt% Kynar 761 and MG-15 exhibit surface charge when undergoing an electrospinning process; however, Kynar MG-15 displays lower charge values than that of Kynar 761. Several critical factors such …

Automated Control System For The Remote-Controlled Torch Positioner, Christopher Ferguson, Anna Abate, Kyle Cramer, Alex Sabitsch, Jacob Stefanko

Williams Honors College, Honors Research Projects

The goal of this project is to design and implement a controls system for Dr. Morscher’s burner rig. The rig serves to simulate jet turbine conditions and test how materials, specifically ceramic matrix composites, react under high temperatures and stresses. Currently, the location of the torch relies solely on manual adjustments and has no automated control system. The improved design will automatically adjust the torch position based on the desired temperature of the sample being tested, therefore maintaining a steady environment for the sample. The current method of manual adjustments for regulating temperature is a crude solution that does not …

Tribo-Corrosion Response Of Additively Manufactured High-Entropy Alloy, Jibril Shittu, Maryam Sadeghilaridjani, Mayur Pole, Saideep Muskeri, Jie Ren, Yanfang Liu, Ismael Tahoun, Harpreet Arora, Wen Chen, Narendra Dahotre

Mechanical and Industrial Engineering Faculty Publication Series

High-entropy alloys (HEAs) with multiple principal elements represent a paradigm shift in structural alloy design and show excellent surface degradation resistance in corrosive environment. Here, the tribo-corrosion response of laser-engineered net-shaped CoCrFeMnNi HEA was evaluated in 3.5 wt% NaCl solution at room temperature. The additively manufactured (AM-ed) CoCrFeMnNi showed five times lower wear rate, regenerative passivation, and nobler corrosion potential during tribo-corrosion test compared to its arc-melted counterpart. A significant anisotropy was seen in the tribo-corrosion response with 45 degrees to the build direction showing better performance compared to tests along the build direction and perpendicular to it. The open …

Strain Effects On The Diffusion Properties Of Near-Surface Self-Interstitial Atoms And Adatoms In Tungsten, Bochuan Sun, Dimitrios Maroudas, Brian D. Wirth, Enrique Martínez

Chemical Engineering Faculty Publication Series

Tungsten (W) is a candidate for the plasma-facing components and divertor in future fusion applications. The material will be subject to a large particle influx (mainly helium and hydrogenic species) that will form bubbles. As bubbles grow, they compress the material, adding to thermal stresses, and eject self-interstitial atoms (SIAs-isolated or in clusters) to release internal pressure. These SIAs diffuse towards the surface in large stress/strain fields and on the surface are thought to act as precursors for nanotendril formation (also known as fuzz) that develops on the material surface modifying its morphology. In this work we analyze the effect …

Development Of Synthetic Coal Char Simulant For Microwave Conversion Studies: A Computationally-Driven Approach, Kevin A. Hager

Graduate Theses, Dissertations, and Problem Reports

Recent experimental demonstration of new reaction windows for coal char/methane reactions that are less energy-intensive, provides innovation for modular reactors. However, the correlation of the exact mechanism for the enhancement of these reaction windows is not certain. This study investigates the simplification of these experimental studies by developing a well-characterized coal char simulant. The approach involves using a computational approach to screen macroscopic composition to replicate the dielectric and compositional response of actual char. This study is focused on PRB coal char. A discrete element method (DEM) technique was used to simulate the packing of coal chars to give the …