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Articles 7081 - 7110 of 16793

Full-Text Articles in Materials Science and Engineering

Phase Separation Dynamics And Morphologies Prediction Of Peo-B-Pmma Copolymer By Atomistic And Mesoscopic Simulations, N Chiangraeng, V S. Lee, P Nimmanpipug Dec 2018

Phase Separation Dynamics And Morphologies Prediction Of Peo-B-Pmma Copolymer By Atomistic And Mesoscopic Simulations, N Chiangraeng, V S. Lee, P Nimmanpipug

Journal of Metals, Materials and Minerals

Atomistic and mesoscopic simulations are the most important tools to predict the morphologies of block copolymers. In this study, inter-bead interactions and essential parameters for meso-structure polymeric models were optimized for poly(ethylene oxide)-block-poly(methyl methacrylate) (PEO-b-PMMA; O-b-M) binary systems. A coarse-grained model in a mesoscopic dynamic was used to represent polymeric chain. Gaussian chain is calculated from polymer chain length concerning its characteristic properties. Free energy density was considered by setting suitable time steps and inter-bead interactions for meso-structure simulations. The interaction energies of 1:1, 2:1 and 4:1 molar ratio of O to M segments were 3.67, 4.66, and 5.92, respectively. …


Tying Together Multiscale Calculations For Charge Transport In P3ht: Structural Descriptors, Morphology, And Tie-Chains, Evan D. Miller, Matthew L. Jones, Eric Jankowski Dec 2018

Tying Together Multiscale Calculations For Charge Transport In P3ht: Structural Descriptors, Morphology, And Tie-Chains, Evan D. Miller, Matthew L. Jones, Eric Jankowski

Materials Science and Engineering Faculty Publications and Presentations

Evaluating new, promising organic molecules to make next-generation organic optoelectronic devices necessitates the evaluation of charge carrier transport performance through the semi-conducting medium. In this work, we utilize quantum chemical calculations (QCC) and kinetic Monte Carlo (KMC) simulations to predict the zero-field hole mobilities of ~100 morphologies of the benchmark polymer poly(3-hexylthiophene), with varying simulation volume, structural order, and chain-length polydispersity. Morphologies with monodisperse chains were generated previously using an optimized molecular dynamics force-field and represent a spectrum of nanostructured order. We discover that a combined consideration of backbone clustering and system-wide disorder arising from side-chain conformations are correlated with …


Enhancing The Durability And The Service Life Of Asphalt Pavements Through Innovative Light-Induced Self-Healing Materials, Marwa Hassan Dec 2018

Enhancing The Durability And The Service Life Of Asphalt Pavements Through Innovative Light-Induced Self-Healing Materials, Marwa Hassan

Data

Corresponding data set for Tran-SET Project No. 17BLSU02. Abstract of the final report is stated below for reference:

"The objective of this study was to evaluate the efficiency of a new generation of Ultraviolet (UV) light-induced self-healing polymers in enhancing the durability and self-healing properties of asphalt mixtures. Self-healing polymers were successfully synthesized in the laboratory and were characterized using Fourier Transform Infrared Spectroscopy (FTIR). In addition, Thermogravimetric Analysis (TGA) results showed that the synthesized polymers achieved the required thermal stability to resist asphalt mixture production processes. Viscosity results showed that addition of 5% Recycled Asphalt Shingle (RAS) and/or 20% …


Development Of A Self-Healing And Rejuvenating Mechanisms For Asphalt Mixtures Containing Recycled Asphalt Shingle, Marwa Hassan Dec 2018

Development Of A Self-Healing And Rejuvenating Mechanisms For Asphalt Mixtures Containing Recycled Asphalt Shingle, Marwa Hassan

Data

Corresponding data set for Tran-SET Project No. 17BLSU06. Abstract of the final report is stated below for reference:

"The objective of this study was to test the hypothesis that hollow-fibers encapsulating a rejuvenator product could improve both self-healing, rejuvenation, and mechanical properties of asphalt mixtures. Hollow-fibers containing a rejuvenating product were synthesized via a wet spinning procedure with sodium-alginate polymer as the encapsulating material. An optimization of the production parameters for the synthesis of fibers was performed to develop fibers suitable for high-temperature and shear stress environment typical of asphalt mixture production. A self-healing experiment was conducted to evaluate the …


Development Of A Self-Powered Structural Health Monitoring System For Transportation Infrastructure, Aydin Karsilaya, Samer Dessouky, Athanassios Papagiannakis Dec 2018

Development Of A Self-Powered Structural Health Monitoring System For Transportation Infrastructure, Aydin Karsilaya, Samer Dessouky, Athanassios Papagiannakis

Data

Corresponding data set for Tran-SET Project No. 17PTAM03. Abstract of the final report is stated below for reference:

"Roadways and bridges play an important role in the economic and social health of society by connecting commerce and people. Economic growth and population expansion pose considerable burden on the aging infrastructure (i.e., pavements and bridges). There is a pressing need to develop structural health monitoring (SHM) technologies capable of collecting infrastructure utilization data. Doing so inexpensively with self-powered systems will revolutionize infrastructure monitoring technology, and will improve decision making enabling roadway and bridge preservation. In this study, a self-powered battery-less structural …


Integrated Health Monitoring And Reinforcement Of Transportation Structures With Optimized Low-Cost Multifunctional Braided Cables, Ibrahim Karaman, Darren Hartl Dec 2018

Integrated Health Monitoring And Reinforcement Of Transportation Structures With Optimized Low-Cost Multifunctional Braided Cables, Ibrahim Karaman, Darren Hartl

Data

Corresponding data set for Tran-SET Project No. 17STTAM04. Abstract of the final report is stated below for reference:

"Corresponding data set for The objective of this research study is to design, fabricate, and characterize multifunctional high strength and self-sensing braided cables and structures using novel Fe-based shape memory alloys (SMAs). The system exploits unique properties of recently developed low-cost super-elastic FeMnAlNi SMAs, which enables excellent super-elastic properties, high strength, and self-sensing in structural health monitoring (SHM) systems. This novel material technology can be coupled with modeling efforts that allow for accurate prediction of both the materials and structural response during …


Consideration Of Key Process Parameters For Achieving Robust And Uniform Cutting Of Ti-6al-4v Sheet Metal Using Fiber Laser With Nitrogen Assisted Gas, V Poshyananda, J Darayen, K Tumkhanon, C Puncreobutr, A Khamkongkaeo, B Lohwongwatana Dec 2018

Consideration Of Key Process Parameters For Achieving Robust And Uniform Cutting Of Ti-6al-4v Sheet Metal Using Fiber Laser With Nitrogen Assisted Gas, V Poshyananda, J Darayen, K Tumkhanon, C Puncreobutr, A Khamkongkaeo, B Lohwongwatana

Journal of Metals, Materials and Minerals

In laser cutting, to work on sensitive and intricate materials, such as titanium, requires rigorous control of parameters to achieve the best cutting results due to high power throughput and rapid cutting speed. Titanium is known for severe reaction with oxygen and nitrogen at elevated temperatures, however the more inert argon assist gas is cost prohibitive in commercial application. To achieve cut quality using nitrogen as an assist gas in titanium cutting, careful control is needed to prevent the formation of hard and brittle martensite as well as nitride- and oxide- phases. To better understand the roles of industrial grade …


Self-Striking Red Glass Fabrication At Low Temperature Using Gold Nanoparticles, Y Ruangtaweep, J Kaewkhao, N Sangwaranatee Dec 2018

Self-Striking Red Glass Fabrication At Low Temperature Using Gold Nanoparticles, Y Ruangtaweep, J Kaewkhao, N Sangwaranatee

Journal of Metals, Materials and Minerals

This research is intended to determine the appropriate condition for gold ruby glass production at low temperature. The effects of reducing agent (SnO2 and SeO2) concentrations on coloration of gold nanoparticle (AuNPs) in glass samples have been investigated. The glasses with chemical compositions of SiO2, B2O3, Al2O3, Na2O, CaO, K2O, Sb2O3, SnO2, SeO2 and AuNPs were fabricated by conventional melt-quench technique at 1,200°C in normal atmosphere. The results found that the red glasses were obtained by SnO2 with concentration of 0.5 wt% and SeO2 with concentration of 0.05 wt%. The color of glasses were confirmed by UV-visible spectrophotometer in the …


Effect Of Zinc Oxide Loaded Polyester Fibers On The Color, Mechanical Properties And Antibacterial Action Of Woven Fabric, P Kampeerapappun Dec 2018

Effect Of Zinc Oxide Loaded Polyester Fibers On The Color, Mechanical Properties And Antibacterial Action Of Woven Fabric, P Kampeerapappun

Journal of Metals, Materials and Minerals

The development of antimicrobial fabrics using zinc oxide (ZnO) embedded polyester fibers have been investigated in the present work. The mechanical properties, tear and tensile strength, of the fabrics have been investigated. The ZnO nanoparticles change the mechanical behavior of the fabrics. The antimicrobial activity of the fabrics was assessed through the bacterial reduction method and the materials showed activity against S. aureus. After three replicate standard washing processes, the bacterial inhibition of fabrics with about 99% reduction still remains. The fabrics exhibit great potential to be used as clothing textiles to protect human body against microbial infections.


Biogenic Synthesis And Antibacterial Activity Of Silver Nanoparticles (Agnps) Produced By Phomopsis Sp. Strain Gfpa2, T Sutjaritvorakul, S Chutipaijit Dec 2018

Biogenic Synthesis And Antibacterial Activity Of Silver Nanoparticles (Agnps) Produced By Phomopsis Sp. Strain Gfpa2, T Sutjaritvorakul, S Chutipaijit

Journal of Metals, Materials and Minerals

Silver nanoparticles (AgNPs) have many applications in different fields such as electronic industries, chemical industries, medical diagnostics and detergent products. In this research AgNPs were produced by Phomopsis sp. GFPA2 isolated from zinc mineral rocks, and were successfully synthesized by using fungal culture broth. The biogenic crystals were investigated and identified by field emission scanning electron microscopy (FE-SEM) equipped with energy dispersive X-ray spectroscopy (EDS) and X-ray powder diffraction (XRD). The spectra confirmed that the biogenic crystals were AgNPs, and they are mostly spherical in shape. The crystals were also tested for their antibacterial activity against human pathogenic bacteria such …


Pr3+ Doped Bao:Zno:B2o3:Teo2 Glasses For Laser Host Matrix, R Rajaramakrishna, C Wongdeeying, P Yasaka, P Limkitjaroenporn, N Sangwaranatee, J Kaewkhao Dec 2018

Pr3+ Doped Bao:Zno:B2o3:Teo2 Glasses For Laser Host Matrix, R Rajaramakrishna, C Wongdeeying, P Yasaka, P Limkitjaroenporn, N Sangwaranatee, J Kaewkhao

Journal of Metals, Materials and Minerals

In this work, glasses of composition (30-x)TeO2-30B2O3-10ZnO-30BaO-xPr2O3 x=0.00 0.05, 0.10, 0.50, 1.00, 1.50 mol% have been prepared through the melt quenching method. In order to characterize and explore their structural properties, we measured the density, refractive index of the glass which shows increasing trend with increase in Pr2O3 concentration also FTIR and XRD spectrum is used to study the structural properties of the developed glasses. XRD shows amorphous structure of the prepared glasses. FTIR shows B-O stretching (BO3)- units and Symmetrical stretching vibration of Te-O in TeO4. The electronic states belonging to the 4f configuration of trivalent Pr3+ were determined …


Properties Of Uv-Curable Screen Printing Inks Containing Oligolactide Acrylates, S Kulsiriswad, O Saravari, K Srikulkit Dec 2018

Properties Of Uv-Curable Screen Printing Inks Containing Oligolactide Acrylates, S Kulsiriswad, O Saravari, K Srikulkit

Journal of Metals, Materials and Minerals

This study was aimed at investigating the properties of UV-curable screen printing inks prepared from oligolactide acrylates. Those resultant inks were applied on substrates and cured by UV radiation. Then, properties of the cured ink films were evaluated and compared with a commercial acrylate ink. The degradation temperature of ink film was found at around 436°C. In addition, thus obtained films were glossy and transparent without yellowness. The weathering resistance of ink films tested by a Xenon test chamber for 500 h showed that ink films exhibited acceptable outdoor durability. Discoloration due to the degradation of lactide chain was observed, …


Temperature Dependence Of Dielectric Properties For Bfo-Bto-Bzt Ceramics, S Unruan, M Unruan, R Yimnirun Dec 2018

Temperature Dependence Of Dielectric Properties For Bfo-Bto-Bzt Ceramics, S Unruan, M Unruan, R Yimnirun

Journal of Metals, Materials and Minerals

In this work, bismuth ferrite-barium titanate-barium zirconate titanate (BFO-BTO-BZT) ceramics were prepared using conventional solid state reaction method. The (1-x)BiFeO3-xBaTiO3 at x = 0.24-0.30 and Ba(Zr,Ti)O3 (Zr = 0.5) systems were separately prepared and calcined at 800 and 1250oC, respectively. All pallets were sintered at temperature of 1100oC. After that, the relationship between phase formation, dielectric and magnetic properties were examined. The XRD patterns revealed that more structural symmetry could be observed in all single-phase perovskite ceramics when more BTO concentration was added. The 0.75(0.70BFO-0.30BTO)-0.25BZT ceramic showed highest dielectric constant with high loss measured at low frequency observed, possibly due …


The Effects Of Concentrations Of Zno Nanoparticles On Dewetting Suppression Of Ps Thin Films, J Thapoung, K Tasurin, N Traiphol, N Pangpaiboon Dec 2018

The Effects Of Concentrations Of Zno Nanoparticles On Dewetting Suppression Of Ps Thin Films, J Thapoung, K Tasurin, N Traiphol, N Pangpaiboon

Journal of Metals, Materials and Minerals

Thin polymer films are widely used in industry, such as protective coating, lubricant and electrical insulator, because of their specific properties. However, thin film in nanoscale tends to separate from substrate; this phenomenon is called Dewetting. In this research, a solution of polystyrenes with a concentration of 0.3 wt% in toluene, providing ~ 21 nm polymeric film, was prepared. Zinc-oxide nanoparticles were added in a polystyrene solution as a Dewetting inhibitor. The concentrations of zinc-oxide were varied from 0 - 1.0 wt%. Thin films were cast by a spin casting machine. After annealing at 90˚C in a vacuum oven for …


Recycled Poly(Ethylene Terephthalate)/Polypropylene/Wollastonite Composites Using Pp-G-Ma As Compatibilizer: Mechanical, Thermal And Morphological Properties, P Chaiwutthinan, S Suwannachot, A Larpkasemsuk Dec 2018

Recycled Poly(Ethylene Terephthalate)/Polypropylene/Wollastonite Composites Using Pp-G-Ma As Compatibilizer: Mechanical, Thermal And Morphological Properties, P Chaiwutthinan, S Suwannachot, A Larpkasemsuk

Journal of Metals, Materials and Minerals

Polymers investigated in this study were recycled poly(ethylene terephthalate) (rPET) as a major phase (matrix) and virgin polypropylene (PP) as a minor phase (dispersed phase). Initially, rPET was melt mixed with four different PP contents (10 - 40 wt%) on a co-rotating twin screw extruder and then injection molded. The blend at 30 wt% PP exhibited the highest impact strength and elongation at break and an acceptable tensile strength and Young's modulus. The 70/30 (w/w) rPET/PP blend was then upgraded its compatibility using 1 - 7 parts by weight per hundred of blend resin (phr) of maleic anhydride grafted PP …


Measuring Characteristic Shrinkage Variability Due To Metal Loading Effects In Low Temperature Co-Fired Ceramic Using Image Processing, John Ezekiel Zumbro Dec 2018

Measuring Characteristic Shrinkage Variability Due To Metal Loading Effects In Low Temperature Co-Fired Ceramic Using Image Processing, John Ezekiel Zumbro

Graduate Theses and Dissertations

Low temperature co-fired ceramic (LTCC) has many benefits when it comes to electronic packaging due to the low dielectric loss, reliability in extreme environments, and high breakdown voltage. Though the ceramic has a lot of benefits it is not widely used due to the high cost and complexities associated with manufacturing. One of these issues with manufacturing is compensating for the shrinkage of the ceramic, this is accomplished by using an expansion factor, creating the “green” or manufactured design. This expansion factor is approximated through knowledge of the ceramic factors such as the metal loading, layers of ceramic tape, firing …


Growth And Behaviors Of Inn/Gan Multiple Quantum Wells By Plasma-Assisted Molecular Beam Epitaxy, Chen Li Dec 2018

Growth And Behaviors Of Inn/Gan Multiple Quantum Wells By Plasma-Assisted Molecular Beam Epitaxy, Chen Li

Graduate Theses and Dissertations

Fully realizing the potential of InGaN semiconductors requires high quality materials with arbitrary In-content. To this date the growth of In-rich InGaN films is still challenging since it suffers from the low growth temperatures and many detrimental alloying problems. InN/GaN multiple quantum wells (MQWs) and super lattices (SLs) are expected to be promising alternatives to random InGaN alloys since in principle they can achieve the equivalent band gap of InGaN random alloys with arbitrarily high In-content and at the same time bypass many growth difficulties.

This dissertation focuses on studying the growth mechanisms, structural properties and energy structures of InN/GaN …


Study Of Conduction Behavior In Dielectrics In Chip Level Interconnects: Detection Of Defects In Al/Sio2 Interconnects, Po-Cheng Lu Dec 2018

Study Of Conduction Behavior In Dielectrics In Chip Level Interconnects: Detection Of Defects In Al/Sio2 Interconnects, Po-Cheng Lu

Material Science and Engineering Dissertations - Archive

This dissertation presents four different electrical measurement techniques to detect structural defects in Al/SiO2 interconnects. These techniques, namely 1) polarity dependence measurement, 2) current voltage measurement, 3) two-point measurement and 4) discharge transient current measurement, can provide simple electrical parameters having direct relationship to defects state (type and quantity) in interconnect structure. All these measurement techniques use the MIM (metal-insulator-metal) structure such as the comb-serpentine structure commonly existing in integrated (IC) devices. This study also presents a newly discovered dielectric failure mechanism, that is the failure by a process of partial discharge dielectric breakdown phenomenon. The goal of the charging …


A Study Of Microcrystalline Cellulose Prepared From Parawood (Hevea Brasiliensis) Sawdust Waste Using Different Acid Types, P Chuayplod, D Aht-Ong Dec 2018

A Study Of Microcrystalline Cellulose Prepared From Parawood (Hevea Brasiliensis) Sawdust Waste Using Different Acid Types, P Chuayplod, D Aht-Ong

Journal of Metals, Materials and Minerals

Microcrystalline cellulose (MCC) from parawood sawdust (PWS) was successfully prepared by acid hydrolysis method. In this work, parawood sawdust waste was obtained from furniture factory. Initially, PWS was subjected to an alkali pulping and bleaching processes, respectively. After that, the microcrystalline cellulose was prepared from bleached pulp using hydrochloric and sulfuric acid in order to compare the effect of acid type. The parameters for acid hydrolysis process were investigated in terms of reaction time and pulp to acid ratio at constant temperature of 80oC. The properties of obtained MCC such as functional groups, degree of polymerization (DP), crystallinity index (CrI), …


Concentrically Loaded Circular Rc Columns Partially Confined With Frp, Sahar Y. Ghanem, Issam E. Harik Dec 2018

Concentrically Loaded Circular Rc Columns Partially Confined With Frp, Sahar Y. Ghanem, Issam E. Harik

Civil Engineering Faculty Publications

Wrapping reinforced concrete (RC) columns with fiber reinforced polymer (FRP) composites is effective in increasing their capacity. The current state of the art concentrates primarily on fully wrapped columns and few studies dealt with partially wrapped ones. The objective herein is to evaluate the effectiveness of partial wraps (or strips) and to develop a confined concrete compressive stress–strain (fc − εc) model that accounts for partial wrapping. Three-dimensional finite element (FE) models are generated to evaluate the influence of different parameters on the behavior of concentrically loaded RC circular columns that are partially and fully wrapped …


Improving Ductility Of Slender Reinforced Concrete Shear Walls With Frp Sheets And Splay Anchors, Luke M. Ostrom Dec 2018

Improving Ductility Of Slender Reinforced Concrete Shear Walls With Frp Sheets And Splay Anchors, Luke M. Ostrom

Architectural Engineering

The Sylmar earthquake of 1971 caused significant damage to slender, non-ductile reinforced concrete (RC) shear wall buildings in California. A later survey by the Concrete Coalition in 2011, under the guidance of EERI members, indicated that there are over 3000 vulnerable concrete buildings in California [8]. This led to City of Los Angeles (LA) Ordinance 193893 enacted in 2015, which requires mandatory upgrades to these concrete buildings by 2035. Current practice to meet the requirements of this ordinance, with respect to RC wall buildings, involves adding new shear walls to the building plan or increasing the cross-sectional area of existing …


Use Of Ultra-High-Performance Fiber-Reinforced Concrete (Uhp-Frc) For Fast And Sustainable Repair Of Pavements, Shih-Ho Chao Dec 2018

Use Of Ultra-High-Performance Fiber-Reinforced Concrete (Uhp-Frc) For Fast And Sustainable Repair Of Pavements, Shih-Ho Chao

Publications

This research presents a new methodology, which enables streets, roads, highways, bridges, and airfields to use an advanced fiber-reinforced concrete material, which can delay or prevent the deterioration of these transportation infrastructure when subjected to traffic and environmental loadings. The major problem of concrete is its considerable deterioration and limited service life due to its brittleness and limited durability. As a result, it requires frequent repair and eventual replacement, which consumes more natural resources. Ultra-high-performance fiber-reinforced concrete (UHP-FRC) introduces significant enhancement in the sustainability of concrete structures due to its dense microstructure and damage-tolerance characteristics. These characteristics can significantly reduce …


A Comprehensive Reliability-Based Framework For Corrosion Damage Monitoring And Repair Design Of Reinforced Concrete Structures, Homero Castaneda, Aydin Karsilaya, Ayman Okeil, Mahmoud Reda Taha Dec 2018

A Comprehensive Reliability-Based Framework For Corrosion Damage Monitoring And Repair Design Of Reinforced Concrete Structures, Homero Castaneda, Aydin Karsilaya, Ayman Okeil, Mahmoud Reda Taha

Publications

In this work, we developed a comprehensive framework for corrosion management of reinforced concrete (RC) structures. This framework includes critical steps of an effective approach to quantify the damage evolution as well as providing the timeframe for effective maintenance/repair strategies for corrosion assessment in RC structures. The framework included several activities including the use of indirect and direct inspection tools, theoretical development for damage prediction, experimental measurements and theoretical development of repair time based on reliability. The uniqueness of the framework is the integration of deterministic modeling of corrosion damage evolution by using mechanistic analysis with statistical modeling on corrosion …


Evaluation Of Comparative Damaging Effects Of Multiple Truck Axles For Flexible Pavements, Stefan Romanoschi, Athanassios Papagiannakis Dec 2018

Evaluation Of Comparative Damaging Effects Of Multiple Truck Axles For Flexible Pavements, Stefan Romanoschi, Athanassios Papagiannakis

Publications

This study aims at evaluating the effect of overlapping flexible pavement strain responses from truck axles that are not part of multiple axle configurations (i.e., tandem, triple and quad). For this purpose, a newly constructed pavement was instrumented with strain gauges installed at the bottom of the asphalt concrete base layer on US-287 south of Mansfield, TX. This pavement structure is typically used for medium- to high-volume roads in the South-Central region of the United States. The strain gauges were used to measure longitudinal and transverse strains under several passes of a test vehicle. This was a class 6 truck …


Plasticity Of Light Metal Matrix Composites Under Anodic Polarization, Y B. Unigovski, E M. Gutman, Z Koren, H Rosenson Dec 2018

Plasticity Of Light Metal Matrix Composites Under Anodic Polarization, Y B. Unigovski, E M. Gutman, Z Koren, H Rosenson

Journal of Metals, Materials and Minerals

Light metal matrix composites (MMCs), reinforced with ceramic particles, demonstrate an improvement in strength, elasticity, and wear resistance with regards to matrix alloys. Unfortunately, the plasticity of MMCs is rather low, and their hardness is relatively high. Therefore, there are serious problems in formability and machinability of these materials. In the present study, an improvement in the surface plasticity of such light MMCs as Al 6063-10% SiC (AMC) and Mg AZ31-10% SiC (MgMC) as well as the high-strength Al 7075 T6 alloy under anodic polarization was observed. To assess the effect of polarization on plasticity of composites, the relative Vickers …


Study On Structure And Luminescence Properties Of Labmoo6:Dy3+ Phosphor For Photonic Material Applications, E Kaewnuam, N Wantana, H J. Kim, J Kaewkhao Dec 2018

Study On Structure And Luminescence Properties Of Labmoo6:Dy3+ Phosphor For Photonic Material Applications, E Kaewnuam, N Wantana, H J. Kim, J Kaewkhao

Journal of Metals, Materials and Minerals

Phosphor powder of LaBMoO6:Dy3+ were prepared to investigate the structure, absorption and luminescence properties. The influence of Dy2O3 concentration on these properties were also studied. XRD characterization represents the main structure of phosphor as monoclinic from LaBMoO6 host matrix. From the reflection spectra, Dy3+ in phosphor can absorb more amount of visible light and near infrared radiation with increasing of Dy2O3 concentration. The energy band gap of LaBMoO6 compound was expanded after doping with Dy2O3 which results to the blue shift of absorption edge. The emission spectra perform the strong yellow and blue light emitting under Dy3+ electric dipole (4F9/2 …


Shape-Controlled Synthesis Of Tungsten Oxide Nanostructures And Characterization, K Petsom, A Kopwitthaya, M Horphathum, Y Ruangtaweep, N Sangwaranatee, J Kaewkhao Dec 2018

Shape-Controlled Synthesis Of Tungsten Oxide Nanostructures And Characterization, K Petsom, A Kopwitthaya, M Horphathum, Y Ruangtaweep, N Sangwaranatee, J Kaewkhao

Journal of Metals, Materials and Minerals

Synthesis of tungsten oxide nanorods and nanodisks were reported here using hydrothermal method. Our study is focusing on the role of hexadecyltrimethyl-ammonium bromide (CTAB) and silver ions in tungsten oxide nanostructure formation comparing with typical methods. The sodium tungstate dehydrate was used as a precursor. We found that optimum concentration of CTAB and silver ions can provide a rod-like structure. Meanwhile, nanodisks were observed at the absence of silver ion. In addition, concentration of silver ions introduced to growth solution plays an important role in obtained nanostructure dimension. All prepared nanostructures were characterized by X-Ray diffraction (XRD) for crystalline structures …


Characterization And Photocatalytic Activity Of Titanium Dioxide Deposited On Stainless Steel By Pulsed-Pressure Mocvd, K Wirandorn, N Panyayao, V Siriwongrungson Dec 2018

Characterization And Photocatalytic Activity Of Titanium Dioxide Deposited On Stainless Steel By Pulsed-Pressure Mocvd, K Wirandorn, N Panyayao, V Siriwongrungson

Journal of Metals, Materials and Minerals

Titanium dioxide (TiO2) was deposited on stainless steel 304 by pulsed-pressure metalorganic chemical vapor deposition (PP-MOCVD). Titanium tetraisopropoxide (TTIP) in toluene at the concentration of 0.5 mol% was used as the precursor. The deposition was conducted at the base pressure of 300 Pa and deposition temperatures were varied between 350°C and 400°C. At these deposition temperatures, anatase phase is expected for further photocatalysis study. The deposited TiO2 thin films at the thickness of hundreds nanometers were analyzed using field emission scanning electron microscopy (FESEM) for surface morphology. X-ray diffraction (XRD) was applied for phase analysis. The contact angle was measured …


Effect Of Chromium Content On The Three-Body-Type Abrasive Wear Behavior Of Multi-Alloyed White Cast Iron, J Opapaiboon, M Supradist Na Ayudhaya, P Sricharoenchai, S Inthidech, Y Matsubara Dec 2018

Effect Of Chromium Content On The Three-Body-Type Abrasive Wear Behavior Of Multi-Alloyed White Cast Iron, J Opapaiboon, M Supradist Na Ayudhaya, P Sricharoenchai, S Inthidech, Y Matsubara

Journal of Metals, Materials and Minerals

The effect of Cr content on three-body-type abrasive wear behavior of multi-alloyed white cast iron was investigated. Multi-alloyed white cast irons were prepared with varying Cr content from 3-9 mass% under basic alloy composition. Annealed specimens were hardened from 1323 and 1373K austenitizing and tempered at three levels of temperatures which were at maximum hardness (HTmax), lower and higher than that at HTmax (L-HTmax and H-HTmax). A rubber wheel wear tester was used to evaluate the abrasive wear resistance. The hardness and volume fraction of the retained austenite (Vγ) varied depending on Cr content and heat treatment condition. The linear …


Improved Gas Sensing Performance Of Ald Azo 3-D Coated Zno Nanorods, P. Lin, X. Chen, K. Zhang, H. Baumgart Dec 2018

Improved Gas Sensing Performance Of Ald Azo 3-D Coated Zno Nanorods, P. Lin, X. Chen, K. Zhang, H. Baumgart

Electrical & Computer Engineering Faculty Publications

This paper reports an enhancement on the sensing performance of ZnO nanorod ethanol sensors with a new approach by utilizing nested coatings of Aluminum doped ZnO (AZO) thin films by Atomic Layer Deposition (ALD) technology. ZnO nanorods were grown by the hydrothermal method with the ZnO seed layer synthesized on Silicon wafers by ALD. To enhance the sensing performance of ZnO nanorod ethanol sensors, multiple coated AZO thin film 3-D coatings were deposited on the surface of the intrinsic ZnO nanorods by ALD.To investigate the sensing performance of the ZnO nanorods sensor for the detection of ethanol vapor, a gas …