Engineering Commons^™

Titanium Dioxide Nanostructures Synthesized By Sonochemical Hydrothermal Process, N Wongpisutpaisan, C Kahattha, N Vittayakorn, A Ruangphanit, W Pecharapa

Journal of Metals, Materials and Minerals

Titanium dioxide particles were prepared by sonochemicalhydrothermal process from a precursor of titanium isopropoxide in the presence of polyvinyl alcohol aqueous solution. Sonication of the precursor was conducted using sonic horn operated at 20 kHz until the completely precipitated product was reached. As-obtained intermediate products were then loaded into a Teflon-lined stainless steel autoclave for hydrothermal process with10M NaOH aqueous solution and heated under different temperature 80-120C. The synthesized products were characterized of structural properties and surface morphology by X-ray diffraction spectroscopy and field emission scanning electron microscope. The results show that prepared samples have a good crystallinity and the …

Crystallization Behavior Of Pla In Pla/Nr Compared With Dynamic Vulcanized Pla/Nr, C Thongpin, S Klatsuwan, P Borkchaiyapoom, S Thongkamwong

Journal of Metals, Materials and Minerals

PLA has been an interesting biopolymer widely used in various applications. It has been widely known that crystallization of PLA is rather slow. After melt processing, crystallinity of PLA could be lost. The study of PLA added with fibers, particles or even nano-particles has been studied extensively. Nonetheless, the suffering in some mechanical characteristic such as toughness has been encountered. Our research was aimed to enhance toughness of PLA by melt blending NR, and dynamic vulcanized NR into PLA using an internal mixer. PLA:NR and PLA:NR vulcanizate with the ratio of 90:10, 80:20, 70:30, 60:40 and 50:50 were studied. Crystallization …

Dissolved Oxygen Sensor Film Using Ruthenium Polypyridine Complex As Luminophore, C Su-Ngam, Sh Thang, A Wongchaisuwat, L Meesuk

Journal of Metals, Materials and Minerals

Ruthenium polypyridine complex was synthesized by using RAFT process. The Ruthenium was immobilized in 2 silicone matrices, polydimethylsiloxane(PDMS) and KE 200 (silicone elastomer base)/CX200 (curing agent). KE 200/CX200 is the alcohols curing type silicone. Both sensor films showed absorption peak at 460 nm and luminescence peak at 610 nm. The KE200/CX200 film gave linear response to dissolved oxygen up to 80% O2 (18 ppm) follow Stern-Volmer equation with R2 of 0.990. The measured luminescence intensity decreased with increasing dissolved oxygen water temperature from 25 to 70c. After being irradiated with 460 nm light source for 3 hrs, the sensor film …

Low Temperature Chemical Precipitation And Characterization Of Ceria Based Ceramic Composite Oxide Materials, D Radhika, A Samson Nesaraj

Journal of Metals, Materials and Minerals

Ceria based ceramic composite oxide materials such as Ce0.9Gd0.1O2-δ -Ce0.9Y0.1O2-δ and Ce0.8Gd0.2O2-δCe0.8Y0.2O2-δ were prepared by a simple chemical precipitation method for application in low temperature solid oxide fuel cells (LTSOFCs) as electrolytes. The precursor materials used in this synthesis were cerium nitrate hexahydrate, gadolinium nitrate and yttrium nitrate (as basic materials), sodium hydroxide (as precipitator material) and PVA (as surfactant). A mixture of metal hydroxides was formed when the aqueous mixture of basic materials mixed with the aqueous precipitant solution in proper stoichiometric composition. The resultant hydroxide mixture was washed with ethanol and water mixture (1:9 volume ratio) to remove …

Macrostructure Modeling Of Al-20 % Sn Alloy, P Padhi, Ak Sahoo, S Kar

Journal of Metals, Materials and Minerals

In metallic alloys, the formation of macrostructure involves different length and time scales. The macrostructure strongly influences the mechanical properties of the materials. Modeling of macrostructure provides valuable insights for tailoring of the structure. In the present study simulation of macrostructure in Al-20Sn has been carried out. Expression for nucleation rate and growth rate were tuned to get a match with the experimentally observed macrostructure. The study incorporates the motion of grains due to Brownian motion. Incorporation of Brownian motion resulted in more uniform distribution locally, which has been experimentally observed. Both simulation and macrograph showed few columnar grains and …

Structural Reliability Analysis Of Corroded Steel Girder Bridge, Mohammed Shaalan Al Badran

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

The natural aging, environmental impact, and appropriate design are certainly playing a serious role in safety of the bridges function. The functional safety of bridge constitutes a prime element of the transportation system serving commuters, passengers and freight. According to Federal Highway Administration, the steel bridges share represents a large amount of the United States’ bridges. In last century, the collapse of both the Silver Bridge at Point Pleasant, West Virginia over the Ohio River on December 15, 1967 and over the Mianus River Bridge in Connecticut on June 28, 1983 showed that steel corrosion has been the leading reason …

Parameters Optimization Of Copper Wire Bonding On Thin Small Outline Package, S Srikamonsirisak, U Tantinuchawong, Y Satirakul

Journal of Metals, Materials and Minerals

With significant rising of Au price, there is growing demand to implement Cu wire bonding as an alternative method for Au wire bonding. However, there are several challenges to overcome because Cu is easily oxidized and its property is harder than Au. The oxidation deteriorates bondability and bond reliability, while the greater wire hardness leads to the more severe wire bonding parameters (higher force, higher power, higher temperature), which results in physical damage of the bond pad and underlying layers. This paper reveals wire bonding parameters optimization in order to implement Cu wire bonding in high volume production environment with …

Application Of Para Rubber Latex Mixed With Organic Dyes As Printing Ink For Biodegradable Plastic Film, T Techochaingam, S Netpradit, K Tanprasert, P Boochathum

Journal of Metals, Materials and Minerals

content of 35.9% and 41.2%, which had the viscosity of 9.52 seconds and drying time of around 5 minutes. The viscosity of Para rubber latex with solid content of 59.0% and 61.4% was very high; thus, resulted in coagulation. Then modified rubber latex CNR with solid content of 16.5%, 19.2%, 26.8% and 28.2%, which had the viscosity around 8.30 seconds and drying time of around 5 minutes. Dye solution was prepared by adding 1 part of dye to 1 part of water (w/w). The formulation of ink that yielded the highest optical density of 1.43 was 8.4 g dye solution …

Conversion Of Secondary Pulp And Paper Sludge To Glucose By Hydrothermal Treatment, N Chariyaprasertsin, Y Matsumura, T Charinpanitkul

Journal of Metals, Materials and Minerals

Secondary pulp/paper sludge is residue from water treatment process of the paper industry. Main components of secondary pulp/paper sludge are cellulose, hemicelluose, lignin and calcium carbonate (CaCO3). The cellulose and hemicellulose could be converted to glucose by hydrothermal treatment in a stainless steel tubular batch reactor. It was found that dried powder of secondary pulp/paper sludge with nominal size in a range of 595 to 840 m contains different content of CaCO3. Therefore, effect of CaCO3 content on glucose yields was examined under designated temperature of 200-260 C and treating time of 0-40 minutes. Identification and quantification of glucose and …

Characterization Of Diamond-Like Carbon (Dlc) Films Deposited By Filtered Cathodic Vacuum Arc Technique, N Konkhunthot, C Euaruksakul, P Photongkam, P Wongpanya

Journal of Metals, Materials and Minerals

Diamond-like carbon (DLC) films were prepared on AISI H13 hot-work tool steel substrates by filtered cathodic vacuum arc (FCVA) technique under variable substrate DC biasing. The atomic structures of the films were investigated by Raman spectroscopy, X-ray photoelectron spectroscopy, and near edge x-ray absorption fine structure spectroscopy. The Raman spectra revealed that when the magnitude of the bias voltage increased, the G peak was shifted toward lower wave numbers, and indicated that the sp3 content in the DLC films increased. The ratios between the sp3 and sp2 bonds in the films were verified by X-ray photoelectron spectroscopy, and the analyses …

Improving The Efficiency Of P3ht:Icba Organic Solar Cells By Modifying The Photoactive Solution Preparation Step, Matthew Blaine Samson

Electrical & Computer Engineering Theses & Dissertations

Organic solar cells (OSCs) are a promising alternative to conventional silicon solar cells. These organic devices offer the promise of facile low cost large scale solution based processing on lightweight, flexible, plastic substrates. At the present state of the technology, however, OSCs exhibit relatively low power conversion efficiencies. To improve these efficiencies, new materials are constantly being developed.

One such material is the fullerene indene-C₆₀ bisadduct (ICBA). When implemented in a poly(3-hexylthiophene-2, 5-diyl) (P3HT) : ICBA bulk heterojunction solar cell, these devices exhibit open circuit voltages exceeding 0.8 V, a value much higher than the devices made implementing phenyl-C …

Field Emission Studies Toward Improving The Performance Of Dc High Voltage Photoelectron Guns, Mahzad Bastaninejad

Mechanical & Aerospace Engineering Theses & Dissertations

Field emission is the main mechanism that prevents DC high voltage photoemission electron guns from operating at the very high bias voltages required to produce low emittance beams. Gas conditioning is shown to eliminate field emission from cathode electrodes used inside DC high voltage photoelectron guns. Measurements and simulation results indicate that gas conditioning eliminates field emission from cathode electrodes via two mechanisms: sputtering and implantation, with the benefits of implantation reversed by heating the electrode. The field emission characteristics of 5 stainless steel electrodes varied significantly upon the initial application of voltage but improved to nearly the same level …

Improving The Stability Of High And Low Bandgap Polymers Organic Photovoltaic Devices Using A Solution Based Titanium Sub-Oxide Interfacial Layer, Kurniawan Foe

Electrical & Computer Engineering Theses & Dissertations

The improvement in device efficiency has brought organic photovoltaic (OPV) devices closer to commercial viability, highlighting the importance of studying the lifetime and stability of OPV devices. At present, the lifetime and stability of OPV devices is much shorter and poor mainly caused by oxygen, moisture, and light resulting in the oxidation on low work function electrodes and the degradation of the morphology of the photoactive layer. To improve the lifetime and stability of the OPV devices, we used newly developed low bandgap polymer, PCDTBT, as the electron acceptor material and a solution based titanium sub-oxide (TiOx) interfacial layer inserted …

Plastic Response Of Dislocation Glide In Solid Helium Under Dc Strain-Rate Loading, Caizhi Zhou, Jungjung Su, Matthias J. Graf, Charles J. Olson Reichhardt, Alexander V. Balatsky, Irene J. Beyerlein

Materials Science and Engineering Faculty Research & Creative Works

We develop a model for the gliding of dislocations and plasticity in solid ⁴He. This model takes into account the Peierls barrier, multiplication and interaction of dislocations, as well as classical thermally and mechanically activated processes leading to dislocation glide. We specifically examine the dc stress-strain curve and how it is affected by temperature, strain rate, and dislocation density. As a function of temperature and shear strain, we observe plastic deformation and discuss how this may be related to the experimental observation of elastic anomalies in solid hcp ⁴He that have been discussed in connection with the possibility …

A Multi-Scale Approach To A Greater Understanding Of The Behavior Of Heterogeneous Materials Under Dynamic Loading, Andrew J. Van Vooren

Master's Theses (2009 -)

The penetration of granular materials is of interest to a variety of different fields, and is an active area of research. The objective of this project is to gain understanding of the dynamics of a projectile penetrating into a granular material. To do this, experiments were run and a numerical model was created.

A dart gun was used to accelerate an aluminum dart to velocities around 100 m/s, which then impacted a target tank filled with Ottawa sand. The dart flew along a view window, which allowed for a recording of the penetration event using a high speed camera. Pressure …

Effect Of Ethyl Propionate On Low-Temperature Performance Of Lifepo4-Based Li-Ion Battery, Xiao-Ping Li, Lian-Sheng Hao, Wei-Shan Li, Meng-Qing Xu, Li-Dan Xing

Journal of Electrochemistry

A linear carboxylic, ester ethyl propionate (EP), was used as the co-solvent of carbonates, ethylene carbonate (EC), ethyl-methyl carbonate (EMC) and dimethyl carbonate (DMC), and its effect on low-temperature performance of LiFePO₄-based Li-ion battery was studied by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic charge-discharge test. The application of EP enhances the ionic conductivity of the electrolyte, improves the compatibility of the electrolyte with both LiFePO₄ and graphite materials, and thus improves the low-temperature performance of LiFePO₄-based Li-ion battery. The Li-ion battery using the optimized electrolyte of 1 mol·L^-1 LiPF₆/EC:EMC:DMC:EP …

Multifunctional Corrosion Inhibition Behavior Of Zn-Al Calcined Layered Double Hydroxides For Steel Rebar In Nacl Solution, Xiao-Juan Zhang, Jing-Jing Wang, Shi-Gang Dong, Chang-Jian Lin

Journal of Electrochemistry

The Zn-Al layered double hydroxides (Zn-Al LDHs) and calcined products (Zn-Al CLDHs) were synthesized successfully under a routine air atmosphere. The results showed that both Zn-Al LDHs and Zn-Al CLDHs had obvious flake structures. The corrosion inhibition of Zn-Al CLDHs for steel rebar in NaCl solution was studied by electrochemical techniques. It was found that the corrosion rate of steel rebar decreased significantly after the steel rebar was treated by Zn-Al CLDHs in NaCl solution for 3 h. It was indicated that Zn-Al CLDHs could absorb Cl^- and release OH^- during their reconstruction process, which provided dual protection …

Influences Of The Cinnamic Acid On Zinc Electrodeposition At Glassy-Carbon Electrode, Kai Li, Shen Chen, Shen-Na Liu, Bi-Sang Chen, Heng Lin, Guo-Liang Chen, Qing-Xiang Wang

Journal of Electrochemistry

The influences of cinnamic acid (CIN) on the mechanism of Zn deposition and nucleation kinetics onto glassy-carbon electrode were studied by cyclic voltammetry (CV) and chronoamperometry (CA). The results revealed that the zinc reduction took place via Zn²⁺ + 2e → Zn in the presence of CIN, but the kinetics of zinc deposition was changed and the formation rate of zinc nuclei was accelerated. In the absence of CIN, the mechanism of zinc nucleation followed the 3D-instantaneous diffusion-controlled nucleation, while the 3D-progressive diffusion-controlled nucleation in the presence of CIN. The addition of CIN reduced the nucleation rate, but increased …

Preparation And Characterization Of A Novel Composite Electrolyte Ceria-Sulfate For Intermediate Temperature Solid Oxide Fuel Cells, Ze Tong, Yi-Mei Yin, Jie-Wei Yin, Zi-Feng Ma

Journal of Electrochemistry

A novel composite electrolyte SDC-(Li/Na)₂SO₄ was prepared for intermediate temperature solid oxide fuel cells (ITSOFC). The phase structure and cross-sectional morphology were examined by XRD and SEM, respectively, and the ionic conductivity was investigated by AC impedance in a temperature range of 400 ^oC ~ 700 ^oC in air. It was found that the composite electrolyte was composed of two phases: crystal SDC and amorphous (Li/Na)₂SO₄. The conductivity of the composite electrolyte was significantly larger than that of SDC at intermediate temperatures (550 ^oC ~ 700 ^oC) and increased …

The Effect Of Precursors On Performance Of Lini0.5Co0.2Mn0.3O2 Cathode Material, Dong-Ge Hu, Zhang-Zhi Wang, Jia-Li Liu, Tao Huang, Ai-Shui Yu

Journal of Electrochemistry

Commercial LiNi_0.5Co_0.2Mn_0.3O₂ material is generally prepared by a combination of co-precipitation and solid state reaction method. The particle size distribution and morphology of Ni_0.5Co_0.2Mn_0.3(OH)₂ precursor have a great impact on the electrochemical performance of LiNi_0.5Co_0.2Mn_0.3O₂. In this work, the crystal structure and surface morphology of LiNi_0.5Co_0.2Mn_0.3O₂ prepared by three different precursors were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Particle size distribution, tap density and electrochemical performance were …

Influence Of Electrode Hydrophobicity On Performance Of Alkaline Polymer Electrolyte Fuel Cells, Li-Sheng Tan, Jing Pan, Yao Li, Lin Zhuang, Jun-Tao Lu

Journal of Electrochemistry

In the present work, we study the influence of the electrode hydrophobicity on the performance of alkaline polymer electrolyte fuel cells (APEFCs). QAPS or xQAPS is employed as the membrane and the ionomer, while PTFE is used as a hydrophobic additive in order to adjust the electrode hydrophobicity. We find that enhancing the hydrophobicity of anode can promote the performance of APEFCs, while a moderate hydrophobicity of cathode is required to achieve optimal performance. By using xQAPS as the electrolyte and adding some PTFE in the anode, a peak power density of 132 mW·cm^-2 can be obtained at a …

Electrocatalytic Mechanism And Porous Electrode Mass Transfer Process In Membrane Electrode Assembly For Direct Methanol Fuel Cells, Xin-Dong Wang, Yi-Tuo Wang, Gui-Cheng Liu, Meng Wang, Zhe Tian

Journal of Electrochemistry

Direct methanol fuel cell (DMFC) is considered to be a promising commercial energy conversion device for portable electronics due to its many advantages. In order to improve the performance of DMFC, many companies and research institutes have been launching the deep research and obtaining a lot of conspicuous achievements. In this paper, the electrocatalytic mechanism and porous electrode mass transfer process in membrane electrode assembly (MEA) are analyzed. In addition, combined with the preparation process of MEA, multilayer ordered structures and internal transfer process of the cell, recent progresses of MEA in DMFC are discussed.

Fabrication And Performance Of Lani0.6Fe0.4O3-δCathode Modified By Coating With Gd0.2Ce0.8O2 For Intermediate Temperature Solid Oxide Fuel Cell, Rui-Xuan Ren, Bo Huang, Xin-Jian Zhu, Yi-Xing Hu, Xiao-Yi Ding, Zong-Yao Liu, Ye-Bin Liu

Journal of Electrochemistry

The symmetric cell of LaNi_0.6Fe_0.4O_3-δ/Sc_0.1Zr_0.9O_1.95/LaNi_0.6Fe_0.4O _3-δ was fabricated with screen printing method. A LaNi_0.6Fe_0.4O_3-δ (LNF) cathode was modified by coating with nano-sized gadolinium-doped ceria (GDC, Gd_0.2Ce_0.8O₂) prepared using a simple combustion process within the pores of the cathode. According to the electrochemical impedance spectra (EIS), the polarization resistance of the pure LNF was 0.70 W·cm² at 750 ºC, while 0.13 W·cm² for the 21.3% GDC (by mass)-coated LNF cathode at the …

Preparation And Electrochemical Performance Of Hollow Carbon Spheres/Sulfur Composite, Jun Zang, Hang Qian, Er-Man Zeng, Juan-Ni Fu, Ming-Sen Zheng, Quan-Feng Dong

Journal of Electrochemistry

Hollow carbon spheres were prepared by the PMMA template. Hollow carbon spheres/sulfur composite was made from sulfur and hollow carbon spheres as a conducting framework. The results of SEM and TEM showed that sulfur was uniformly filled in both of the shell and hollow core of hollow carbon spheres. The electrochemical performance of hollow carbon spheres/sulfur composite was characterized by the charge/discharge method. The results showed the excellent rate and cycle performance of hollow carbon spheres/sulfur composite. The reversible capacities of hollow carbon spheres/sulfur composite are 1145 mAh·g^-1, 824 mAh·g^-1, 702 mAh·g^-1, 586 mAh·g …

Progress Of Lithium Rich Cathode Materials For Li-Ion Batteries, Jie Zhang, Jiu-Lin Wang, Jun Yang

Journal of Electrochemistry

Lithium rich materials xLi₂MnO₃·(1-x)LiMO₂ (0-1 and low cost. However, the large irreversible capacity during the first cycle, low rate capability and structure collapse during cycling remain impediments in developing these cathodes for applications. The structure analyses and charge/discharge mechanisms for lithium rich materials are currently main research contents. Although whether the lithium rich materials are solid solutions or composite is still controversial, oxygen release mechanism on the first charge 4.5 V plateau of lithium rich materials has come to consistency. Several modifications, such as bulk doping, surface coating and microstructure control, demonstrate promising strategies to …

Electrochemical Performance Of Al-Doped Spinel Limn2O4 Cathode Material For Li-Ion Batteries, Yong-Long Wang, Wen-Ge Wang, Qian Zhang, Xin Wang, Jian-Sheng Cao, Shi-Hai Ye

Journal of Electrochemistry

Spinel LiMn₂O₄, a cathode material for Li-ion batteries, is featured as good high-rate performance, low cost and environmental friendly. The pristine and Al-doped LiMn₂O₄ samples were prepared by sol-gel method. The structure and micromorphology of the as-prepared samples were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results demonstrated that the as-prepared LiMn₂O₄ samples had a typical cubic spinel structure and were composed of sphere-like particles with a diameter range of 300 ~ 500 nm. Galvanostatic charge-discharge tests showed that the LiMn₂O₄ samples doped …

Polypyrrole-Transition Metal-Oxygen Coordination Complexes As High Performance Lithium Storage Material, Ya Mao, Qingyu Kong, Bingkun Guo, Zhaoxiang Wang, Liquan Chen

Journal of Electrochemistry

No abstract provided.

Engineering Performance Of A New Siloxane-Based Corrosion Inhibitor, Niall Holmes, R. O'Brien, P. A. M. Basheer

Articles

This paper presents an evaluation of a new non-toxic corrosion inhibitor on selected engineering properties of concrete mixes with different cementitious materials following a corrosion and durability study on concrete samples. Corrosion inhibitors consist of powders or solutions which are added to concrete when mixed to prevent or delay corrosion of steel by their reaction with ferrous ions to form a stable and passive ferric oxide film on the steel surface. The new inhibitor functions slightly differently and its corrosion inhibition effect is due to the formation of a siloxane coating on the steel surface. Therefore, the performance of the …

The Equi-Biaxial Fatigue Characteristics Of Epdm Under True (Cauchy) Stress Control Conditions, Mark Johnson

Conference Papers

Strain amplitude control is most often employed when carrying out fatigue testing of rubber components. Often the design engineer requires fatigue test data that is based on load amplitude control. This is analogous to engineering or nominal stress amplitude control. This usually makes it easy to maintain the load within the specified test limits during extended testing. Values of true stress and strain can be obtained from this approach, but the magnitudes of the maximum true stresses in these tests increase with accumulated cycles, whereas the equivalent maximum engineering stress values remain constant. This is easily demonstrated in the uniaxial …

The Equi-Biaxial Fatigue Characteristics Of Epdm Under True (Cauchy) Stress Control Conditions, Mark Johnson, Ray Ekins, Niall Murphy, Stephen Jerrams, John Hanley

Conference Papers

ABSTRACT: Strain amplitude control is most often employed when carrying out fatigue testing of rubber components. Often the design engineer requires fatigue test data that is based on load amplitude control. This is analogous to engineering or nominal stress amplitude control. This usually makes it easy to maintain the load within the specified test limits during extended testing. Values of true stress and strain can be obtained from this approach, but the magnitudes of the maximum true stresses in these tests increase with accumulated cycles, whereas the equivalent maximum engineering stress values remain constant. This is easily demonstrated in the …