Materials Science and Engineering Commons^™

Influence Of Saturation Nonequilibrium And Variable Operation Conditions On The Electromechanical Performance Of Ionic Polymer Metal Composite Actuator Architectures, Allison Maria Arnold

Graduate Theses, Dissertations, and Problem Reports (ETD)

Electroactive polymers (EAPs) continue to gain attention for their potential to offer unique and versatile solutions in the soft robotic and flexible electronic industries. Ionic Polymer-Metal Composites (IPMCs) are a class of ionic-type EAPs which can be configured as capacitor actuators with very low voltage requirements (≤ 5 V AC or DC). Their compact, portable, and lightweight properties, coupled with a biomimetic bending actuation response make them ideal for human-machine integrated technologies such as medical implants, active skins, and artificial muscles. The Nafion-based IPMC can be described as a layered composite capacitor containing an ionic polymer core, sandwiched between chemically …

Carbon Monoxide Sensing Of Nickel Oxide At 1000 ℃ To 1200 ℃ For In Situ Combustion Control: Behavior, Mechanism, And Application, Yi Wang

Graduate Theses, Dissertations, and Problem Reports (ETD)

An advanced smart sensor network is essential to a combustion system, which is in favor of in situ, locally placed, and low-cost gas sensors. However, most chemical/electrochemical sensors fail to work in a combustion boiler, due to the demanding working temperatures (> 1000 ℃). This work for the first time reports a well-functioning mixed-potential type CO sensor at 1000 ℃ - 1200 ℃ using nickel oxide (NiO) as the sensing material. The influence of feed gas flow rate, electrode thickness, and porosity on sensor behavior is investigated, delivering notable and fast responses to 1000 ppm in 3% O₂: …

Modeling, Fabrication, And Characterization Of Rf-Based Passive Wireless Sensors Composed Of Refractory Semiconducting Ceramics For High Temperature Applications, Kavin Sivaneri Varadharajan Idhaiam

Graduate Theses, Dissertations, and Problem Reports (ETD)

Real-time health monitoring of high temperature systems (>500^oC) in harsh environments is necessary to prevent catastrophic events caused by structural failures, varying pressure, and chemical reactions. Conventional solid-state temperature sensors such as resistance temperature detectors (RTDs) and thermocouples are restricted by their operating environments, sensor dimensions and often require external power sources for their operation. The current work presents the research and development of RF-based passive wireless sensing technology targeting high temperatures and harsh environmental conditions. Passive wireless devices are generally classified as near-field and far-field devices based on the interrogation distance. Near-field sensors are placed at …

Development Of Oxide Dispersion Strengthening (Ods) Alloys Powder For Additive Manufacturing, Changyu Ma

Graduate Theses, Dissertations, and Problem Reports (ETD)

Additive manufacturing (AM) fabricated oxide dispersion strengthened (ODS) alloys are given high expectations for critical structural components such as the first stage turbine blade for their excellent creep strength and oxidation resistance compared to superalloys. However, the powder feedstock processing is still an open question since current state-of-the-art processes are not capable of achieving ultrafine strengthening elements such as Y₂O₃ in powder which leads to agglomeration issues in as-consolidated alloys. In this research, the oxidation behavior and stability of ultrafine oxide in AM-printed alloys using mechanically alloyed powders were evaluated at 1100 ^oC. In addition, a …

Combinatorial Approaches For Effective Design, Synthesis, And Optimization Of Enzyme-Based Conjugates, Jordan Scott Chapman

Graduate Theses, Dissertations, and Problem Reports (ETD)

The specificity and efficiency with which enzymes catalyze selective chemical reactions far exceeds the performance of traditional heterogeneous catalysts that are predominant in industrial applications such as conversion of commodity chemicals to value-added products, fuel cells, and petroleum refinement. Moreover, biocatalysts exhibit exceptionally high product turnover at ambient conditions with little health and environmental burden. These advantageous qualities have led to the prolific use of enzyme catalysis in pharmaceutical, detergents, and food preservation industries wherein their use has greatly reduced waste generation, Unfortunately, the full slate of benefits that enzymes can impart to a broader range of chemical processes is …

Theoretical Investigation Of Sofc/Soec Degradation Mechanisms And Mitigations, Fuming Jiang

Graduate Theses, Dissertations, and Problem Reports (ETD)

America has a rapid growth in the development of renewable power generation in the twenty-first century. Hydrogen energy especially is the major topic in development of renewable power generation because it has the ability to provide for energy in transportation, combined heat and power generation and energy storage systems with little or no impact on the global ecosystem. Electrolysis and fuel cell technology for hydrogen energy storage has brought interest to the researchers worldwide.

Solid oxide electrolysis cells (SOECs) and Solid oxide fuel cells (SOFCs) are promising hydrogen energy technologies that can utilize chemical energy to produce and store electricity. …

Microwave-Assisted Carbon Nanotube Growth From Methane On Surface Catalyst Exsolving Perovskite Oxide, Angela M. Deibel

Graduate Theses, Dissertations, and Problem Reports (ETD)

The novel method of using a perovskite exsolution catalyst, strontium titanium nickel oxide (STNO), proved capable of simultaneously producing carbon nanotubes (CNTs) and CO_x-free hydrogen during methane decomposition under microwave irradiation. An optimization of common perovskite materials was conducted for microwave-responsiveness with the results reported in this study. Out of the materials screened, strontium titanium nickel oxide (STNO) was the best candidate to achieve an acceptable methane conversion rate as well as a decent responsiveness to microwave. STNO was further optimized through Ni content, reduction dwell time, and reduction temperature to produce the best methane conversion and CNT …

Hydrophobically Modified Isosorbide Dimethacrylates As Biomaterials For Bisphenol A Free Dental Fillings, Bilal Marie

Dissertations

Amalgam and Bisphenol A glycerolate dimethacrylate (BisGMA) are the main dental filling materials in use today. Because of the negative perception of amalgam and its lower esthetic appeal, as well as the desire to replace the endocrine disruptor Bisphenol A, which is the building block of BisGMA, there has been a critical need to search for safer alternatives to these dental filling materials.

Isosorbide is a sugar-based molecule generally recognized as safe. It has been extensively studied as a replacement to the Bisphenol A core in various materials. However, isosorbide is extremely hygroscopic, and water uptake in dental fillings causes …

Electro-Chemo-Mechanics Of The Interfaces In 2d-3d Heterostructure Electrodes, Vidushi Sharma

Dissertations

Unique heterostructure electrodes comprising two-dimensional (2D) materials and bulk three dimensional (3D) high-performance active electrodes are recently synthesized and experimentally tested for their electrochemical performance in metal-ion batteries. Such electrodes exhibit long cycle life while they also retain high-capacity inherent to the active electrode. The role of 2D material is to provide a supportive mesh that allows buffer space for volume expansions upon ion intercalation in the active material and establishes a continuous electronic contact. Therefore, the binding strength between both materials is crucial for the success of such electrodes. Furthermore, battery cycles may bring about phase transformations in the …

Experimental And Computational Studies Of Functionalized Carbon Nanotubes For Use In Energy Storage Devices And Membranes, Emine S. Karaman

Dissertations

Electrolytes with good interfacial stability are a crucial component of any electrochemical device. The development of novel gel polymer electrolytes (GEs) with good interface stability and better manufacturability is important for the development of the next generation electrochemical devices. Gel electrolytes are hybrid electrolyte materials, combining benefits of both liquid and solid systems. Compared with liquid and solid electrolytes, GEs open new design opportunities and do not require rigorous encapsulation methods. In this dissertation, studies on functionalized carbon nanotubes (fCNTs) and graphene oxide (GO) doped polyvinyl alcohol (PVA) based gel electrolytes (GEs) are reported. The ionic conductivity and mechanical strength …

Electric-Field-Driven Processes In Multiphase Fluid Systems, Qian Lei

Dissertations

Advantages of using electric fields in miniaturized apparatuses for a wide range of applications are revealed by numerous experimental and theoretical studies over the last several decades as it offers a simple and efficient method for manipulation of multiphase fluid systems. This approach is considered to be especially beneficial for control of boiling processes and colloidal suspensions considered in the presented work.

Boiling. Today's trends for enhancing boiling heat transfer in terrestrial and space applications focus on removal of bubbles to prevent formation of a vapor layer over the surface at a high overheat. In contrast, this dissertation presents a …

Flexible Microfluidic Device With Nonplanar Interdigitated Microelectrodes, Saud Alssaidy

Theses

The lab-on-a-chip concept has improved significantly in recent years to meet global demand for various applications with the advent of new technologies. Much progress has been achieved, but many microfluidic devices still suffer from design limitations in terms of sensitivity and selectivity because they use rigid, fragile substrate materials and conventional electrodes, which do not provide high sensitivity or selectivity and suffer from signal-to-noise ratio issues. This work proposes a novel device architecture that uses flexible, transparent top and bottom layers integrated with (nonplanar interdigitated microelectrodes) to create a sandwich-like flexible substrate base. The top and bottom layers consist of …

Critical Analysis Of Material Consumption And Cost Reduction Techniques For The Apparel Cutting Processes, Ismael Taifa, Ibrahim Twaha, Mboka A Mwakibambo

Tanzania Journal of Science

Revenues generation in the garment industry is synonymous with material consumption. This study thus analysed material consumption and cost reduction techniques in the Tanzanian garment industry. The research employed quantitative (experimentation) and qualitative approaches (document review and observation technique) in the apparel cutting processes. Experimental results of material consumption from ten tests averaged efficiency of 78.67%, the wasted pieces (19.2%), and unnoticed waste (2.03%). Essential considerations to reduce material waste include: digitalising the fabric cutting processes; providing workers training; deploying appropriate practices in the cutting room (e.g. pattern engineering and pattern accuracy); considering the quality of the procured fabric and …

New Type Of Lightweight Aggregate For Use In Structural Concrete, Jamal Khatib, Ali Jahami, Oussama Baalbaki, Adel Elkordi

BAU Journal - Science and Technology

This research studied the utilization of municipal solid waste incineration bottom ash (MSWI-BA) in lightweight coarse aggregate (LWC) production. A special method was followed to prepare the new aggregate to fully replace the normal aggregates (NWA) in concrete. The mechanical properties such as compressive strength, tensile strength, and elasticity modulus were investigated for the LWC concrete. Then, two beams were prepared; one from LWC and the other from NWC. The structural performance of beams made up of lightweight aggregates compared to normal aggregates was investigated. The results showed that this type of aggregates led to a 20% reduction in concrete …

Numerical Investigation On The Effect Of Spectral Radiative Heat Transfer Within An Ablative Material, Raghava S. C. Davuluri, Rui Fu, Kaveh A. Tagavi, Alexandre Martin

Mechanical Engineering Faculty Publications

The spectral radiative heat flux could impact the material response. In order to evaluate it, a coupling scheme between KATS - MR and P1 approximation model of radiation transfer equation (RTE) is constructed and used. A Band model is developed that divides the spectral domain into small bands of unequal widths. Two verification studies are conducted: one by comparing the simulation computed by the Band model with pure conduction results and the other by comparing with similar models of RTE. The comparative results from the verification studies indicate that the Band model is computationally efficient and can be used to …

A Comparison Of Solid Electrolyte Interphase Formation And Evolution On Highly Oriented Pyrolytic And Disordered Graphite Negative Electrodes In Lithium-Ion Batteries, Haoyu Zhu, Joshua A. Russell, Zongtang Fang, Pete Barnes, Lan Li, Corey M. Efaw, Allison Muenzer, Jeremy May, Kailash Hamal, I. Francis Cheng, Paul H. Davis, Eric J. Dufek, Hui Xiong

Materials Science and Engineering Faculty Publications and Presentations

The presence and stability of solid electrolyte interphase (SEI) on graphitic electrodes is vital to the performance of lithium-ion batteries (LIBs). However, the formation and evolution of SEI remain the least understood area in LIBs due to its dynamic nature, complexity in chemical composition, heterogeneity in morphology, as well as lack of reliable in situ/operando techniques for accurate characterization. In addition, chemical composition and morphology of SEI are not only affected by the choice of electrolyte, but also by the nature of the electrode surface. While introduction of defects into graphitic electrodes has promoted their electrochemical properties, how such structural …

Cyclic Voltammetric Simulations On Batteries With Porous Electrodes, Xue-Fan Cai, Sheng Sun

Journal of Electrochemistry

Lithium-ion batteries (LIBs) are among the most widely used energy storage devices. Whole-cell modeling and simulations of LIBs can optimize the design of batteries with lower costs and higher speeds. The Pseudo-Two-Dimensional (P2D) electrochemical model is among the most famous whole-cell models and widely applied in LIB simulations. P2D model consists of a series of kinetic equations to model Li⁺/Li diffusion in working/counter electrodes and electrolytes, which are filled in the porous electrodes and separator, and reactions at the interface of electrolyte and active particles. The traditional applications of P2D model, however, are limited to the cases where …

Effect Of Aluminum Alloy Surface Modification On Adhesion Of The Modified Polyurethane Coating And Its Corrosion Protective Performance, Xian-Yin Kuang, Shao-Qiang Jin, Yan-Hui Cao, Yan-Mei Zhang, Shi-Gang Dong, Long-Hui Zhu, Li-Wen Lin, Chang-Jian Lin

Journal of Electrochemistry

The ordinary organic coatings on aluminum alloy usually encounter a problem of low adhesion to the substrate, which results in destruction and failure of the long-term protective performance of the anticorrosion systems. The surface modification of aluminum alloy is able to enhance the adhesion of organic coating on aluminum alloys, and to improve their protective performance. In this work, a combined surface modification of anodic oxidation and mussel adhesion protein/CeO₂/3-aminopropyltriethoxysilane composite film (MCA) was developed on the aluminum alloy. The adhesion of modified polyurethane coated on the treated aluminum alloy and its corrosion protective performance were evaluated comprehensively …

Influence Of Heat Treatment Time On Cathode Material Cr8O21 For Lithium Battery, Jiu-Kang Teng, Qing-Jie Wang, Liang Zhang, Hong-Mei Zhang, Xiao-Tao Chen, Peng Zhang, Jin-Bao Zhao

Journal of Electrochemistry

Chromium oxide (Cr₈O₂₁) cathode material for lithium batteries was synthesized by thermal decomposition of chromium trioxide (CrO₃) at high temperature. The electrochemical properties of chromium oxide depended on the time and temperature during the heat treatment. Pure phase chromium oxide was prepared, and the effects of heat treatment time on the structures and electrochemical properties of Cr₈O₂₁ were systematically studied. The first discharge mechanism of chromium oxide in lithium batteries was explored, and the results were similar to that in lithium-sulfur batteries. The crystal phases and electrochemical properties of the prepared …

Effect Of Glycol Based Coolant Pollution On Pem Fuel Cells Stack And Recovery Measures, Cong-Yi Zhu, Xiao-Hui Li, Quan-Quan Gan

Journal of Electrochemistry

As the heat conduction medium of fuel cell cooling system, coolant is very important for the thermal management of fuel cell stack. In practical application, coolant leakage into the stack often occurs. Due to the randomness of fault location of components, the location of coolant leakage is uncertain, which may occur on the cathode side or anode side of some or all single cells. The main effects of coolant pollution on fuel cell stack are as follows: the output of open circuit voltage decreases sharply, the consistency of single cells voltage decreases and so on, which seriously affects the normal …