Materials Science and Engineering Commons^™

Titanium Incorporated Gallium Oxide (Ga-Ti-O): Structure Property Relationship And Performance Evaluation For Extreme Environment Applications, Sandeep Manandhar

Open Access Theses & Dissertations

The existing power generation systems, which utilize fossil fuels, are in dire need of efficient, reliable chemical sensors that can operate safely at higher temperatures. These sensors control the combustion environment and the emissions during combustion. Several sensing materials such as SnO2, ZnO, TiO2, WO3, and Ga2O3 exhibit high sensitivity to certain type of chemical molecules and in a certain range of temperatures. Among these candidate materials, β-Ga2O3 is stable at very high temperatures and has shown functionality for oxygen sensing at higher temperatures (>700°C). However, the response time and sensitivity must be significantly improved in order to derive …

Plasmon-Enhanced Optical Sensing By Engineering Metallic Nanostructures, Peng Zheng

Graduate Theses, Dissertations, and Problem Reports (ETD)

The world’s booming population projected to reach 10 billion by 2050 causes enormous stresses on environmental safety, food supply, and healthcare, which in return threatens human civilizations. One of the most promising solutions lies at innovating point-of-care (POC) sensing technologies to conduct detection of environmental hazards, monitoring of food safety, and early diagnosis of diseases in a timely and accurate manner. The discovery of surface-enhanced spectroscopy in the 1970s has significantly stimulated research on light-matter interaction which gives rise to enhanced optical phenomena such as surface-enhanced Raman scattering (SERS), plasmon-enhanced fluorescence (PEF), and particularly, they have found enormous applications in …

Detection Of Buried Non-Metallic (Plastic And Frp Composite) Pipes Using Gpr And Irt, Jonas Kavi

Graduate Theses, Dissertations, and Problem Reports (ETD)

This research investigated alternative strategies for making buried non-metallic pipes (CFRP, GFRP, and PVC) easily locatable using Ground Penetrating Radar (GPR). Pipe diameters up to 12" and buried with up to 4 ft. of soil cover were investigated. The findings of this study will help address the detection problem of non-metallic pipelines and speed the adoption of composite pipes by the petroleum and natural gas industry. The research also investigated the possibility of locating buried pipes transporting hot fluids using Infrared Thermography (IRT).

Results from the study have shown that, using carbon fabric and aluminum tape overlay on non‑metallic pipes …

Near-Net Forming Complex Shaped Zr-Based Bulk Metallic Glasses By High Pressure Die Casting, Lehua Liu, Tao Zhang, Zhiyuan Liu, Chunyan Yu, Xixi Dong, Liangju He, Kuan Gao, Xuguang Zhu, Wenhao Li, Chengyong Wang, Peijie Li, Laichang Zhang, Lugee Li

Research outputs 2014 to 2021

Forming complex geometries using the casting process is a big challenge for bulk metallic glasses (BMGs), because of a lack of time of the window for shaping under the required high cooling rate. In this work, we open an approach named the “entire process vacuum high pressure die casting” (EPV-HPDC), which delivers the ability to fill die with molten metal in milliseconds, and create solidification under high pressure. Based on this process, various Zr-based BMGs were prepared by using industrial grade raw material. The results indicate that the EPV-HPDC process is feasible to produce a glassy structure for most Zr-based …

Novel Contact Materials For Improved Performance Cdte Solar Cells, Angus Rocket, Robert Collins, Sylvain Marsillac

Electrical & Computer Engineering Faculty Publications

This program has explored a number of novel materials for contacts to CdTe solar cells in order to reduce the back contact Schottky barrier to zero and produce an ohmic contact. The project tested a wide range of potential contact materials including TiN, ZrN, CuInSe₂:N, a-Si:H and alloys with C, and FeS₂. Improved contacts were achieved with FeS₂. As part of understanding the operation of the devices and controlling the deposition processes, a number of other important results were obtained. In the process of this project and following its conclusion it led to research …

Nonlinear Coupled Effects In Nanomaterials, Sia Bhowmick

Theses and Dissertations (Comprehensive)

Materials at the nanoscale have different chemical, structural, and optoelectrical properties compared to their bulk counterparts. As a result, such materials, called nanomaterials, exhibit observable differences in certain physical phenomena. One such resulting phenomenon called the piezoelectric effect has played a crucial role in miniature self-powering electronic devices called nanogenerators which are fabricated by using nanostructures, such as nanowires, nanorods, and nanofilms. These devices are capable of harvesting electrical energy by inducing mechanical strain on the individual nanostructures. Electrical energy created in this manner does not have environmental limitations. In this thesis, important coupled effects, such as the nonlinear piezoelectric …

Studying Mass And Mechanical Property Changes During The Degradation Of A Bioadhesive With Mass Tracking, Rheology And Magnetoelastic (Me) Sensors, Zhongtian Zhang

Dissertations, Master's Theses and Master's Reports

In this research, the degradable polymer 4-arm poly (ethylene glycol)-glutaric acid-dopamine (PEG-GA-DM₄) was synthesized. The degradation behavior of crosslinked PEG-GA-DM₄ bioadhesive was studied with mass tracking, oscillatory rheology, and magnetoelastic (ME) sensors. Changes in mechanical properties were correlated with both dry mass and wet mass changes during the degradation. The results indicate that the loss of mechanical property in the bioadhesive can take place without losing the dry mass. The mass loss profile cannot describe the degradation behavior completely. In addition to studying the degradation of PEG-GA-DM₄, this research also confirms the application of ME …

Nondestructive Evaluation Of Salvage White Spruce, Tyler Hovde

Dissertations, Master's Theses and Master's Reports

Knowledge of wood quality in dead standing trees is an important topic with recent increases in defoliation across North America. Obtaining wood quality information for defoliated trees would help stakeholders in the timber products industry sort and sell salvaged material for the highest possible value. This research investigates the ability to measure wood quality of white spruce (Picea glauca) after spruce budworm (Choristoneura fumiferana) attack using acoustic nondestructive evaluation. We compared stress wave velocities measured on standing trees to trees’ visual appearance. After harvest and processing of selected trees into bolts, standing-tree stress wave velocities were compared to bolt acoustic …

A Scientific Approach To Understanding The Head Trauma Endured By A Mixed Martial Arts Fighter, John William Michael Sorbello

Mechanical & Aerospace Engineering Theses & Dissertations

The purpose of this research is to gain some insight on the type of head trauma an athlete may encounter during mixed martial arts (MMA) competition. These athletes endure continuous blows to the head throughout their training and fighting career. The knowledge obtained from this research may assist MMA athletes and trainers in assessing the way they train, how they compete and, more importantly, how long they choose to compete in their amateur or professional MMA career.

The analysis is performed by first creating a three-dimensional solid model of the human head based on geometric coordinates originally obtained from a …

Black Silicon – Optical Properties And Applications, Sita Rajyalaxmi Marthi

Dissertations

Crystalline Silicon (c-Si) is one of the most abundant and widely used semiconductors. Si is a semiconductor with indirect bandgap. The average reflectance of Si is about 30% in the visible range of wavelengths. Standard Si solar cells are not entirely useful in the infrared spectrum region. In order to make Si useful in a wide spectral range, the surface of Si is modified to reduce the reflectance of Si. The silicon thus modified is called Black Silicon (BSi).

This dissertation describes the model based on effective medium approximation to determine the effective optical constants, refractive index and extinction coefficient …

Formulation Of Uv Curable Resins Utilized In Vat Photo Polymerization For The Additive Manufacturing Of Gun Propulsion Charge In 3d Printers, David T. Bird

Theses

Formulating resins for Additive Manufacturing (AM), utilizing UV laser stereolithography, is a new technique that makes it possible for the fabrication of complex geometries with high dimensional resolution. This layer by layer photopolymerization approach spans various industrial sectors from adhesives, inks and optical fibers to nanotechnology and biomaterials. UV curable resins such as epoxides, vinyl ethers and other acrylates are important monomers that offer effective mediums for energetic materials, and the potential exists to develop environmentally friendly formulations with suspended energetic materials at various solids loading levels.

Developing techniques for UV curing formulations of highly loaded energetic suspensions is a …

Electrical Properties Of Metal/Wse2structures, Zeel Rajiv Gandhi

Theses

The formation of low resistance metal contacts on two-Dimensional layer (2-D) of WSe2 is a big challenge. In this research, a comparative study is presented on the electrical properties of metal/WSe2 Schottky barrier diodes with various metals such as Au, In, Al, and Ga in the temperature range of 80K to 400K well within the domain of thermionic emission theory.

Topics covered here include the factors that determine the Schottky barrier height, the device capacitance, and its current-voltage (I-V) characteristics. I-V curves for different metals on WSe2 are analyzed as function of temperature. Barrier height is determined from Au-nWSe2 Schottky …

Electroactivities Of Pd/Fe3O4-C Catalysts For Electro-Oxidation Of Methanol, Ethanol And Propanol, Tao Zou, Qing-Feng Yi, Yuan-Yuan Zhang, Xiao-Ping Liu, Guo-Rong Xu, Hui-Dong Nie, Xiu-Lin Zhou

Journal of Electrochemistry

Development of palladium (Pd) catalysts with high electroactivity for alcohol oxidation is significant for alcohol fuel cells. In this work, Pd nanoparticles were formed by sodium borohydride (NaBH₄) reduction method and subsequently deposited on the surface of carbon supported ferriferrous oxide (Fe₃O₄/C) composites to obtain the Pd/Fe₃O₄-C catalysts with different Fe₃O₄ loadings. Their transmission electron microscopic (TEM) images show that the Pd nanoparticles were uniformly dispersed on the Fe₃O₄/C. Electroactivities of the prepared Pd/Fe₃O₄-C catalysts toward oxidations of C1-C3 …

Cobalt-Based Nitrogen-Doped Carbon Non-Noble Metal Catalysts For Oxygen Reduction Reaction, Meng-Xiu Jiang, Jing Zhang, Yue-Hua Li, Rong Zhang

Journal of Electrochemistry

Transition metal-nitrogen co-doped carbon catalysts have attracted significant attention because of their reasonable activity and remarkable selectivity toward oxygen reduction reaction (ORR) as cathodic reaction in fuel cells. However, the role of transition metal in the active sites of the catalysts still is uncertain. In this work, the Co_x-N_y/C-T catalysts were prepared with BP2000 as a carbon source, urea (Ur) as a nitrogen source and Co(OAc)₂•4H₂O as a metal precursor by a simple chemical method. Meanwhile, in order to optimize the ORR activity, the catalysts were synthesized with different amounts of Co …

Core-Shell Pd@Pt Ultrathin Nanowires As Durable Oxygen Reduction Electrocatalysts, Xin Wang, Yun-Jie Xiong, Liang-Liang Zou, Qing-Hong Huang, Zhi-Qing Zou, Hui Yang

Journal of Electrochemistry

This paper describes a simple CO-assisted reduction approach for the controllable synthesis of ultrathin Pd nanowires along the one-dimensional (1D) direction. Ultrathin Pt films from one to several atomic layers were successfully decorated onto ultrathin Pd nanowires by utilizing Cu UPD deposition, and followed by in-situ redox replacement reaction of UPD Cu by Pt. The core–shell structure and composition of the Pd@Pt ultrathin nanowires have been verified using transmission electron microscopy and energy dispersive X-ray spectrometry. The core–shell Pd@Pt ultrathin nanowires exhibited comparative electrocatalytic activity and improved durability for the oxygen reduction reaction in comparison with commercial Pt black. The …

Effect Of Allyl Thiourea On Nickel Electrodeposition From Solution Containing Ammonia And Chloride, Ya-Ning He, Liang Yuan, Zhi-Ying Ding, Shi-Jun Liu

Journal of Electrochemistry

The effects of allylthiourea (ATU) concentration on the cathodic polarization behaviour, nucleation and surface morphology of nickel electrodeposited on the glassy carbon electrode from ammonia-ammonium chloride-water (NH₃-NH₄Cl-H₂O) solutions were investigated by cyclic voltammogry, cathodic polarization and current transient methods. The results revealed that the addition of ATU inhibited nickel deposition, which was enhanced with an increase in ATU concentration from 5 to 50 mg•L^-1. The initial deposition kinetics corresponded to a model including instantaneous nucleation and diffusion controlled growth. In the presence of ATU, the initial nucleation of nickel electrocrystallisation remained unchanged. …

Effects Of Jet Milling And Classifying Process On The Performance Of Lifepo4/C In Full Batteries, Xing-Liang Liu, Mao-Ping Yang, Wei-Wei Wang, Yong Cao

Journal of Electrochemistry

The carbon coated lithium iron phosphate (LiFePO₄/C) composite cathode material was prepared by using iron phosphate process. The effects of jet milling and classifying process on the electrochemical performance of LiFePO₄/C cathode material in full batteries were investigted. Scanning electron microscopic analyses suggested that the globose secondary particles were crustily crushed during the jet milling and classifying process, which would further result in lower tap density and carbon content. The LiFeP₄/C composite cathode materials with different physical characteristics were further tested in full batteries to evaluate the electrochemical properties. The results showed no obvious …

Engineering The Electrochemical Capacitive Properties Of Activated Carbon By Correct Selection Of Ionic-Liquid Electrolytes, Qiu-Hong Zhang, Bao-Shou Shen, Song-Lin Zuo, Xin-Yu Wei

Journal of Electrochemistry

In order to improve the electrochemical capacitive properties and to apply coconut shell activated carbon (AC) serving as electrode materials in ionic liquid (IL)-based supercapacitor (SC), the coconut shell AC material was re-activated using a steam as an activating agent in this work, forming a secondary AC (W-AC). The results showed that the specific capacitance of the W-AC electrode was much larger than that of the raw activated carbon electrode (R-AC) in 1-ethyl-3-methylimidazolium tetrafluoroborate ([EMIM]BF₄). The electrochemical techniques including cyclic voltammetry (CV), galvanostatic charge/discharge (GCD) measurement, and electrochemical impedance spectroscopy (EIS) were used to systematically study the capacitive …

Effect Of Fe2+/Fe3+Interconvertion On Reduction Behavior Of Fe3+ In Acidic Electrolytes, Jian-Xin Qin, Feng Lin, Wen-Ping Liu, Chao Chen, Meng-De Ren

Journal of Electrochemistry

The influences of ferrous/ferric (Fe²⁺/Fe³⁺) interconvertion on electrochemical reduction and electrode reaction of Fe³⁺ were investigated by using linear sweep voltammetry, potentiostatic method and cyclic voltammetry (CV) in acidic electrolytes containing chloride ion (Cl^-) and sulfate ion (SO₄^2-). It was shown that the reduction process of Fe³⁺/Fe²⁺ would take place in two independent stages: (1) the reduction of Fe³⁺ to Fe²⁺ at E=0.35V and (2) the co-precipitation of Fe²⁺ by forming Fe(OH)₂ (E≤-0.3 V) instead of Fe. The major effect of Fe^{2+ …}

Effect Of Calcium On Atmospheric Corrosion Resistance Of Bridge Steel, Dong-Liang Li, Gui-Qin Fu, Miao-Yong Zhu

Journal of Electrochemistry

The corrosion behavior of bridge steel in simulated hot and humid industrial-marine atmosphere was investigated by mass loss analysis, XRD, SEM, electrochemical methods and a wet/dry alternate immersion corrosion test using 0.1 mol•L^-1 NaCl+0.01 mol•L^-1 NaHSO₃ solutions. The corrosion depth (W) of experimental steels before and after calcium treatment versus time (t) curves showed a good agreement with the power function of W=Atⁿ. The corrosion products were mainly composed of amorphous phase and a small amount of crystals including α-FeOOH, β-FeOOH, γ-FeOOH and Fe₃O₄. Trace calcium could promote the formation of …

Preparation Of Nis2 Nanosheet And Its Application In Asymmetric Supercapacitor, Yuan-You Wang, Ya-Nan Liu, Dang-Qin Jin

Journal of Electrochemistry

In this work, the NiS₂ nanosheets have been synthesized using Ni(OH)₂  as a precursor through a sacrificial template method. The microstructure and chemical composition of as-prepared NiS₂ were characterized by XRD, EDS, BET, SEM and TEM techniques. The results showed that both Ni(OH)₂  and NiS₂  were composed of nanoplates. The electrochemical tests revealed that NiS₂ exhibited the high specific capacitance of 1067.3 F•g^-1 at a current density of 1 A•g^-1 and excellent rate performance. Furthermore, in order to evaluate the practical application of NiS₂, an asymmetric supercapacitor, NiS₂ as …

Applications Of N-Methyl-N-Butyl-Pyrrolidinium Bromide And N-Methyl-N-Ethyl-Pyrrolidinium Bromide In Zn-Br Flow Batteries, Qi Zhang, Miao-Miao Zhang, Lin Meng

Journal of Electrochemistry

It is extremely important for battery performance and safety in Zn-Br flow battery to use quaternary ammonium salts as complex agents for bromine. In this work, the effects of electrolyte compositions and concentrations on the electrode reactions and battery performances were studied in the absence and presences of N-methyl-N-ethyl-pyrrolidinium bromide (MEP) or N-methyl-N-butyl-pyrrolidinium bromide (MBP). The conductivities in the electrolytes containing different constitutions and concentrations were measured by EIS method. The charge-discharge performance for the battery and the complex ability for bromine in different electrolytes were also investigated. The results showed that the electrolyte containing MBP was better than that …

Kinetics And Mechanism Toward Electrochemical Reductions Of Sodium Bromide And Methanol Over Iron Electrodes, Qun Liao, Shu-Feng Zhang, Wen-Hua Leng

Journal of Electrochemistry

It is of technological value and scientific interest to the electro-synthesis of ferrocene, conversion of carbon dioxide (CO₂) and organic electro-synthesis in non-aqueous solutions by investigating the kinetics and mechanism toward electrochemical reductions of sodium bromide (NaBr) and methanol over iron electrodes. However, few reports in the related researches are available. In this article, the kinetics and mechanism toward electrochemical reductions of NaBr and methanol over iron electrodes were examined in detail by carrying out the polarization curve and electrochemical impedance spectroscopic measurements. The results showed that methanol was the reactant, while Na⁺ ions were functioned only …

Effect Of Peg-Coating On Properties Of Lithium-Sulfur Battery Cathode Material Containing Carbon Fiber Conductive Agent, Jie-Cheng Tan, Yan-Hong Tian, Xue-Jun Zhang, Kai-Le Fan

Journal of Electrochemistry

The composite materials contained high modulus carbon fiber (HMCF) were successfully prepared by employing a ball-milling process based on the coating treatment of polyethylene glycol (PEG), and their structures and morphologies were characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) techniques．The influences of PEG content on sulfur cathode capacity, cycle stability and rate performance were systematically studied. It was found that by the pre-coating of PEG, the cathode exhibited the high initial discharge specific capacity of 1312.5 mAh⋅g^-1 at a current rate of 0.2C, and the reversible discharge capacity of 650 mAh⋅g …

Capacity Fading Analyses Of Lini0.5Co0.2Mn0.3O2And Lini0.5Co0.2Mn0.3O2/Lifepo4 Cathode Materials For Lithium-Ion Battery, Yi Hu, Xiang-Zhu He, Zhong-De Deng, Ling-Yong Kong, Wei-Li Shang

Journal of Electrochemistry

The LiNi _0.5Co _0.2Mn _0.3O₂/LiFePO₄ (NMC532/LFP) composite cathode material for lithium-ion battery was prepared by wet ball-milling. The capacity fading behaviors of LiNi _0.5Co _0.2Mn _0.3O₂ (NMC532) and LiNi _0.5Co _0.2Mn _0.3O₂/LiFePO₄ (NMC532/LFP) were analyzed by X-ray diffraction (XRD), scanning electron microscope (SEM), charge/discharge and electrochemical impedance spectroscopy (EIS) tests. The results indicated that the capacity retention values of NMC532/LFP were 97.80% and 86.48%, respectively, after 50 cycles and 60℃ high temperature storage. The NMC532/LFP exhibited better cycle performance and high temperature storage performance. …

Inorganic Biodegradable Substrates For Devices And Systems, Chang-Soo Kim, Richard K. Brow, D. E. Day

Electrical and Computer Engineering Faculty Research & Creative Works

Disclosed are biodegradable glass substrates that are useful as functional elements of solid-state devices. In particular, biodegradable glass substrates having a rapidly degradable glass and a slowly degradable glass provide a structural platform that completely dissolves following a desired operational lifetime of devices such as implanted electronic devices, implanted sensor devices, and optical fibers.

Microstructure And Mechanical Properties Of Additive Manufacturing Titanium Alloys After Thermal Processing, Ahmet Alptug Tanrikulu

Dissertations and Theses

Titanium alloys are widely used for aerospace and biomaterial applications since their high specific strength, and high corrosion resistivity. Besides these properties, titanium is an excellent biocompatible material widely used for internal body implants. Because the products have complex geometries in both applications, Additive Manufacturing (AM) methods have been recently applied for production. AM methods can process a direct 3-D shape of the final product, decrease total production time and cost. However, high residual stress of the final product limits the application of AM components, especially the ones that are exposed to cyclic loading. In the present study, the initial …

Investigation Of 2195 And 2219 Post Weld Heat Treatments For Additive Friction Stir Lap Welds, Matthew Champagne

LSU New Orleans Theses and Dissertations

To evaluate potential uses for friction stir welding in additive manufacturing, two separate parts were fabricated, one of 2195-T84 and the other 2219-T87, utilizing fixed pin techniques and additive lap welds. The parts were cut into samples, artificially aged and subjected to Rockwell hardness (HRB), Vickers hardness, micrographic photography, and metallographic imaging on both pre- and post- heat treatment. Additionally, tensile testing was performed on the heat-treated samples. A comparisons of test results showed a minimal increase in the yield strength of the 2195-T84 samples compared to as-welded tensile results obtained from a previous project. The ultimate tensile strength was …

Design, Manufacture, And Structural Dynamic Analysis Of A Biomimetic Insect-Sized Wing For Micro Air Vehicles, Jose Enrique Rubio

LSU New Orleans Theses and Dissertations

The exceptional flying characteristics of airborne insects motivates the design of biomimetic wing structures that can exhibit a similar structural dynamic behavior. For this purpose, this investigation describes a method for both manufacturing a biomimetic insect-sized wing using the photolithography technique and analyzing its structural dynamic response. The geometry of a crane fly forewing (family Tipulidae) is acquired using a micro-computed tomography scanner. A computer-aided design model is generated from the measurements of the reconstructed scanned model of the insect wing to design the photomasks of the membrane and the venation network required for the photolithography procedure. A composite …

The Role Of Catalytic Residue PKA On The Hydrolysis/Transglycosylation Partition In Family 3 Β-Glucosidases, Inacrist Geronimo, Christina M. Payne, Mats Sandgren

Chemical and Materials Engineering Faculty Publications

β-Glucosidases (βgls) primarily catalyze the hydrolysis of the terminal glycosidic bond at the non-reducing end of β-glucosides, although glycosidic bond synthesis (called transglycosylation) can also occur in the presence of another acceptor. In the final reaction step, the glucose product or another substrate competes with water for transfer to the glycosyl-enzyme intermediate. The factors governing the balance between the two pathways are not fully known; however, the involvement of ionizable residues in binding and catalysis suggests that their pK_a may play a role. Through constant pH molecular dynamics simulations of a glycoside hydrolase Family 3 (GH3) βgl, we …