Extraction Of Tin From Hardhead By Oxidation And Fusion With Sodium Hydroxide,
2012
Chulalongkorn University
Extraction Of Tin From Hardhead By Oxidation And Fusion With Sodium Hydroxide, C Bunnakkha, C Jarupisitthorn
Journal of Metals, Materials and Minerals
In this research work, the extraction of tin from tin-iron alloy or hardhead which is the intermediate product obtained during tin smelting was investigated. The hardhead containing 32.40 wt% Sn and 45.81 wt% Fe was ground to different sizes and oxidized at 500 to 800 °C for 1 to 6 hours to form SnO2 and Fe2O3. The results indicated that an increase in oxidation temperature decreased the required oxidation time. However using too high oxidation temperature (800 °C) resulted in sintering of the oxide product.In sodium hydroxide fusion stage, effects of fusion temperature, fusion time, NaOH quantity and oxide product …
Tribological Behavior Of Austenitic Stainless Steel And Vanadium Carbide Coated By Trd Process,
2012
Chulalongkorn University
Tribological Behavior Of Austenitic Stainless Steel And Vanadium Carbide Coated By Trd Process, C. Lertlummeechai, P. Sricharoenchai
Journal of Metals, Materials and Minerals
In forming austenitic stainless steel sheet, galling is the major cause of tool steels failure. Coating on tool surface is an effective way to lessen galling tendency. In this paper, vanadium carbide coating by TRD process was conducted on tool steel and intentionally tempered in air to produce thicker vanadium oxide on vanadium carbide surface. Ring-on-disc wear test was conducted by sliding with austenitic stainless steel ring to investigate tribological behavior. Weight of ring was measured before and after wear tests. Chemical composition of ring surface was crosssection analyzed by EPMA. Surface of the disc was analyzed by XPS. Wear …
Preparation Of Organosilane Treated Microcrystalline (Simcc) And Simcc/Polypropylene Composites,
2012
Chulalongkorn University
Preparation Of Organosilane Treated Microcrystalline (Simcc) And Simcc/Polypropylene Composites, P. Thummanukitcharoen, S. Limpanart, K. Srikulkit
Journal of Metals, Materials and Minerals
In this study, the silane treated microcrystalline cellulose (SiMCC)/polypropylene composite was prepared. In the first step, the surface modification of microcrystalline cellulose (MCC) with various concentrations of hexadecyltrimethoxysilane was carried-out in order to obtain the SiMCC having good compatibility with PP matrix. Characterizations including SEM, FT-IR, TGA and DSC were employed to analyze the structure of SiMCC. SEM revealed that MCC surface morphology was changed from rod shape into rough particles after silane treatment. In the next step, the obtained SiMCC was mixed with PP powder using twin-screw extruder. Based on TGA results, it was found that the addition of …
Low-Cycle Fatigue Of Thermally-Cycled Carbon-Epoxy Composite,
2012
Chulalongkorn University
Low-Cycle Fatigue Of Thermally-Cycled Carbon-Epoxy Composite, Ya. B. Unigovski, A. Grinberg, E. M. Gutman, R. Shneck
Journal of Metals, Materials and Minerals
Investigation of low-cycle fatigue of composites is of vital importance for the design of structural components. In this study, the effects of thermal cycling on low-cycle fatigue behavior of carbon-epoxy laminate are investigated in a purely bending mode at strain ratios of -1 and 0.1. It is found that a very small increase in the plastic strain amplitude catastrophically shortens the fatigue life N of the composite determined as a number of cycles corresponding to 0.9 of the initial force. The preliminary thermal cycling of the composite at the temperature varied from 180°C to −195.8°C shortens N values in comparison …
Three-Body-Type Abrasive Wear Behavior Of 26% Cr Cast Iron With Molybdenum,
2012
Chulalongkorn University
Three-Body-Type Abrasive Wear Behavior Of 26% Cr Cast Iron With Molybdenum, A. Chooprajong, P. Sricharoenchai, S. Inthidech, Y. Matsubara
Journal of Metals, Materials and Minerals
Hypoeutectic 26 wt% Cr cast irons without and with Mo were prepared in order to investigate their abrasion wear resistance. The annealed specimens were hardened from 1323 K (As-H) and then tempered at three levels of temperatures between 673 and 823 K for 7.2ks, the temperature giving the maximum hardness (HTmax), lower temperature than that at HTmax (L-HTmax ) and higher temperature than that at HTmax (H-HTmax). The abrasive wear resistance was evaluated using Rubber Wheel abrasion test (three-body-type). It was found that hardness and volume fraction of retained austenite (V) in the heat-treated specimens varied with the Mo content …
The Oxidation Behaviour Of Stainless Steel Aisi 409 Coated By Decorative Nickel-Chromium Plating,
2012
Chulalongkorn University
The Oxidation Behaviour Of Stainless Steel Aisi 409 Coated By Decorative Nickel-Chromium Plating, T. Wongpinij, T. U-Dom, T. Suptrakun, T. Puttanasun, C. Pimpan, N. Nangnoi, P. Wongpanya
Journal of Metals, Materials and Minerals
The continuous and cyclic oxidation behaviour of ferritic stainless steel AISI 409 surfacecoated by decorative nickel-chromium plating was studied. Firstly, the plated AISI 409 steel samples were cut into rectangular pieces of 20x10x3 mm. Nickel plating was electroplated with various times, i.e., 0, 5, 10 and 15 minutes; subsequently the decorative chromium plating was performed for 5 minutes. Then, the samples were exposed to 200ºC and 300ºC. The degradation of samples was evaluated by considering weight alteration after oxidation test. The oxidation product and surface of samples were characterized by optical microscope and scanning electron microscope (SEM) with energy dispersive …
Failure Analysis Of Bearings In Air Conditioning Compressor,
2012
Chulalongkorn University
Failure Analysis Of Bearings In Air Conditioning Compressor, P. Promdirek, A. Leidig, T. Keawjarus, P. Tong-In
Journal of Metals, Materials and Minerals
Two journal bearings of a compressor were failed in service. The wear which led to crack was observed at the internal surface of both bearings. The objective of this analysis is to evaluate the reason for the wear found on the internal bearings surface. Two bearings were returned from field and others in several conditions were examined. Electron probe micro analyzer and microhardness was used for metallurgical analysis. It revealed that bearing consisted of two different layers: 1) Fe-base and 2) Al-Sn alloy. Surface worn at the internal surface which composed of Al-Sn alloy was found. The results also showed …
Corrosion Behavior Of Aisi 4140 Steel Surface Coated By Physical Vapor Deposition,
2012
Chulalongkorn University
Corrosion Behavior Of Aisi 4140 Steel Surface Coated By Physical Vapor Deposition, C. Keawhan, P. Wongpanya, N. Witit-Anun, P. Songsiriritthigul
Journal of Metals, Materials and Minerals
The corrosion behavior of uncoated and CrN-coated onto AISI 4140 steel was studied by electrochemical technique. Firstly, the AISI 4140 steel samples were solution heat treated and oil quenched in order to achieve proper hardness. Then, they were surface-prepared with alteration of surface roughness by using SiC paper at different numbers of 180, 600, and 1200 prior to CrN coating. The samples were coated with CrN film by physical vapor deposition (PVD) technique. The corrosion behavior of the uncoated and CrN-coated samples was studied in air-saturated 3.5 wt% NaCl solution at the pH values of 2, 7 and 10 at …
A Micromechanical Flow Curve Model For Dual Phase Steels,
2012
Chulalongkorn University
A Micromechanical Flow Curve Model For Dual Phase Steels, S. Sodjit, V. Uthaisangsuk
Journal of Metals, Materials and Minerals
In the automotive industries, Dual Phase (DP) steels have become a favoured material for the car body parts due to their excellent combination of high strength and good formability. A microstructure of DP steel generally consists of a matrix of ferrite reinforced by small islands of martensite. Experimental investigations showed that effects of martensite phase fraction, morphology, and phase distribution play an important role for the mechanical and fracture behaviours of the dual phase steel. In the present work, an approach concerning FE based modelling for predicting flow curve of DP steels has been introduced using a Representative Volume Element …
Diamond This Film Patterning Technique Using Selective Nucleation Growth, Characterization And Application,
2012
Old Dominion University
Diamond This Film Patterning Technique Using Selective Nucleation Growth, Characterization And Application, Weican Xiao
Electrical & Computer Engineering Theses & Dissertations
Diamond is the hardest bulk material with the highest thermal conductivity. It is also an excellent wide band gap material; hence, diamond is suitable for electronic, mechanical and biological applications. Unfortunately, natural diamond is prohibitively expensive for most technological applications. Polycrystalline diamond, with properties close to those of natural diamond, has been synthesized since the 1950s. Among many methods employed for diamond thin film synthesis, chemical vapor deposition (CVD) using microwave plasma (MW) is quite popular for several reasons. Well-confined plasma that does not touch the reaction chamber walls can be produced directly on the substrate. Hence, contamination in the …
Multidentate Resorcinarene Surfactants For The Phase Transfer Of Metal Nanoparticles And Nanodiamonds: Applications In Catalysis And Diamond Film Growth,
2012
Old Dominion University
Multidentate Resorcinarene Surfactants For The Phase Transfer Of Metal Nanoparticles And Nanodiamonds: Applications In Catalysis And Diamond Film Growth, Vara Prasad Sheela
Chemistry & Biochemistry Theses & Dissertations
One main objective of the present work is to functionalize cuboctahedral platinum nanoparticles with various multidentate resorcinarene surfactants and study their influence in determining their catalytic activity. We hypothesized that catalytically active and recyclable catalysts can be achieved by incomplete yet strong passivation of the nanoparticle surfaces by using multidentate resorcinarene surfactants. We have developed phase transfer protocols for functionalizing cuboctahedral platinum nanoparticles with resorcinarene thiol or amine. Fluorescence assay confirmed that both these nanoparticles contained almost comparable unpassivated metal area. The activity of such phase transferred nanoparticles was tested in the catalytic hydrogenation of allyl alcohol. The conversion of …
Porous Niti Produced By Nitita Transient-Liquid-Assisted Method,
2012
Chulalongkorn University
Porous Niti Produced By Nitita Transient-Liquid-Assisted Method, O. Worasub, A. Bansiddhi
Journal of Metals, Materials and Minerals
This work presents a novel method for preparing porous NiTi by powder metallurgy using a vacuum sintering technique. Tantalum was used as a transient liquid phase creator, which enhanced the sinterability of NiTi powders. The effect of Ta content and powder packing on the degree of densification were investigated. The porous NiTi exhibited shape memory behavior and a large recovery strain, analyzed by differential scanning calorimetry and compressive testing, respectively, making the material promising for bone implant applications. In addition, macroporosity was created by using NaCl spaceholders. Adding 3 atomic percent of Ta and 60 volume percent NaCl space-holder resulted …
Nr/Xsbr Nanocomposites With Carbon Black And Carbon Nanotube Prepared By Latex Compounding,
2012
Chulalongkorn University
Nr/Xsbr Nanocomposites With Carbon Black And Carbon Nanotube Prepared By Latex Compounding, A. Boonmahitthisud, S. Chuayjuljit
Journal of Metals, Materials and Minerals
Two series of natural rubber/carboxylated styrene butadiene rubber (NR/XSBR) (80/20) nanocomposites containing different loadings of carbon black (CB) (3-9 phr) and carbon nanotube (CNT) (0.1-0.4 phr) have been prepared by a latex stage compounding method. Before mixing with NR/XSBR blended latex, CB and CNT were dispersed and stabilized in water by ball milling with the aid of surfactant. The obtained compounded latex was cast into sheet on a glass mold and thereafter cured in an oven at 80°C for 3 h. The tensile properties (tensile strength, modulus at 300% strain, elongation at break), dynamic mechanical properties (loss tangent, storage modulus) …
Spin Diffusion In Bulk Gan Measured With Mnas Spin Injector,
2012
Missouri University of Science and Technology
Spin Diffusion In Bulk Gan Measured With Mnas Spin Injector, Shafat Jahangir, Fatih Dogan, Hyun Kum, Aurelien Manchon, Pallab Bhattacharya
Materials Science and Engineering Faculty Research & Creative Works
Spin injection and precession in bulk wurtzite n-GaN with different doping densities are demonstrated with a ferromagnetic MnAs contact using the three-terminal Hanle measurement technique. Theoretical analysis using minimum fitting parameters indicates that the spin accumulation is primarily in the n-GaN channel rather than at the ferromagnet (FM)/semiconductor (SC) interface states. Spin relaxation in GaN is interpreted in terms of the D'yakonov-Perel mechanism, yielding a maximum spin lifetime of 44 ps and a spin diffusion length of 175 nm at room temperature. Our results indicate that epitaxial ferromagnetic MnAs is a suitable high-temperature spin injector for GaN.
Effects Of Rare-Earth Doping On Femtosecond Laser Waveguide Writing In Zinc Polyphosphate Glass,
2012
Missouri University of Science and Technology
Effects Of Rare-Earth Doping On Femtosecond Laser Waveguide Writing In Zinc Polyphosphate Glass, Luke B. Fletcher, Jon J. Witcher, Neil Troy, Signo Tadeu Dos Reis, Richard K. Brow, Denise M. Krol
Materials Science and Engineering Faculty Research & Creative Works
We have investigated waveguide writing in Er-Yb doped zinc polyphosphate glass using a femtosecond laser with a repetition rate of 1 KHz. We find that fabrication of good waveguides requires a glass composition with an O/P ratio of 3.25. The dependence on laser writing parameters including laser fluence, focusing conditions, and scan speed is reported. Waveguide properties together with absorption and emission data indicate that these glasses can be used for the fabrication of compact, high gain amplifying devices.
Numerical Analysis And Design Optimization Of Organic Bulk Hetero-Junction Solar Cells Using The Mixed Finite Element And Arc-Length Methods,
2012
Old Dominion University
Numerical Analysis And Design Optimization Of Organic Bulk Hetero-Junction Solar Cells Using The Mixed Finite Element And Arc-Length Methods, James L. Dean
Mechanical & Aerospace Engineering Theses & Dissertations
Due to the high coupling and non-linear nature of the semiconductor equations, numerical stability becomes a major problem when using a purely Newtonian numerical method in solving these equations. Presented is a robust mixed finite element formulation with application for organic solar cell devices that incorporates the arc-length predictor-corrector method to bypass such stability issues. The simulated device represents a multilayered solar cell using organic bulk hetero-junction materials including donor materials Poly[2,1,3-benzothiadiazole-4,7-diyl[4,4-bis(2-ethylhexyl)-4H-cyclopenta[2,1-b:3,4- b']dithiophene-2,6-diyl]] (PCPDTBT) and poly 3-hexylthiophene (P3HT) with acceptor fullerene materials [6,6]-phenyl C61 butyric acid methyl ester (PC61BM) or [6,6]-phenyl C71 butyric acid methyl ester (PC71BM) as the photoactive …
Comments On Internal Alternating Current Resistance Test Standard And Methods Of Lithium-Ion Batteries,
2012
Weifang Wina Green Power Co., Ltd., Shouguang 262705, Shandong, China
Comments On Internal Alternating Current Resistance Test Standard And Methods Of Lithium-Ion Batteries, Ya-Li Zhang, Sen Xin, Yu-Guo Guo, Li-Jun Wan
Journal of Electrochemistry
The sustainable development of energy and environment is one of the most influential issues of this century. Batteries, especially secondary batteries are important for powering out daily life. However, in many practical applications, such as in electric vehicles and hybrid electric vehicles, batteries should be used in packs and the performance consistency of each battery in the pack should be taken into consideration. As one of the performance parameters being used to characterize the battery consistency, internal resistance is of great importance to the industrial fabrication and the use of batteries. Currently, internal resistance tests of secondary batteries, such as …
Simple Analysis And Possible Solutions Of The Unusual Interfacial Reactions In Li-S Batteries,
2012
College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, China;
Simple Analysis And Possible Solutions Of The Unusual Interfacial Reactions In Li-S Batteries, Xin-Ping Ai, Yu-Liang Cao, Han-Xi Yang
Journal of Electrochemistry
Rechargeable Li-S batteries are a promising power source with realizable energy densities several times higher than current Li-ion batteries. However, the capacity utilization and cycling stability of the existing Li-S technologies are still insufficient for battery applications. The causes for the electrochemical instability of this redox system arise probably from the changes in the surface structures and electrochemical microenvironments of the Li anode and sulfur cathode during charge-discharge reactions, which includes the frustrated electron transfer in the sulfur-carbon interface, the dissoluble diffusion of the polysulfide intermediates, and the shuttle reaction inbetween the sulfur and Li electrodes. To deal with these …
Application Of First Principles Calculations In Anode Materials For Lithium Ion Batteries,
2012
Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education) Nankai University, Tianjin 300071,China
Application Of First Principles Calculations In Anode Materials For Lithium Ion Batteries, Tian-Ran Zhang, Dai-Xin Li, Si-Qi Yang, Zhan-Liang Tao, Jun Chen
Journal of Electrochemistry
First principles calculations play an important role in the study and development of new materials for lithium batteries. In this paper, we review the application of first principles calculations in the design of anode materials, including the modeling of the interaction of lithium in the anode materials, capacity, voltage, electrochemical reaction process, diffusion, rate capability, the relationship between the structure and properties, and the experimental phenomena interpreting. Based on the discussions, we emphasize on the importance of first principles calculations and demonstrate their requirement for further development.
An Overview Of Electrode Materials In Microbial Fuel Cells,
2012
Key Laboratory of Jiangxi Province for Ecological Diagnosis-Remediation and Pollution Control, Nanchang Hangkong University, Nanchang 330063, China;
An Overview Of Electrode Materials In Microbial Fuel Cells, Su-Qin Ci, Na Wu, Zhen-Hai Wen, Jing-Hong Li
Journal of Electrochemistry
Microbial fuel cells (MFCs) are devices that can directly convert organic chemical energy into electrical energy with microbial as catalysts. MFCs are a promising bio-electrochemical system with the potential to degrade organic sewage and produce electricity. This article supplies a critical and comprehensive review for the electrode materials concerning about anode and cathode in MFCs, including the fabrications, functional modifications and surface constructions of electrode materials, as well as their applications in MFCs. Additionally, the existing problems of electrode materials in current MFCs have been demonstrated in order to provide the guideline for exploring the next-generation electrode materials for MFCs.
