First-Principles Studies Of Perovskite Compounds For Thermoelectric Applications,
2015
Carnegie Mellon University
First-Principles Studies Of Perovskite Compounds For Thermoelectric Applications, Penelope E. Ackerman, Lan Li (Mentor)
Idaho Conference on Undergraduate Research
Computational modeling techniques have been used to provide detailed insights into the structure-property relationships of materials. We have collaborated with the National Institute of Standards and Technology to develop various perovskite compounds with desired thermoelectric properties. We have used density functional theory-based approaches to study structural stability and electrical properties of R2(FeCo)O6 perovskite compounds (R = Pr, Nd, Sm, Eu and Gd), for which Fe and Co randomly occupy the B-site. Vienna ab-initio simulation package (VASP) has been performed to optimize geometry and structure. Superlattice and locally disordered phases have been compared through a total energy minimization …
Extraction And Characterization Of Cellulose Nanocrystals Produced By Acid Hydrolysis From Corn Husk,
2015
Chulalongkorn University
Extraction And Characterization Of Cellulose Nanocrystals Produced By Acid Hydrolysis From Corn Husk, Piyaporn Kampeerapappun
Journal of Metals, Materials and Minerals
Corn husk is one of the agricultural residues represent abundant, inexpensive, and readily available source of renewable lignocellulosic biomass. Cellulose nanocrystals (CNCs) were extracted from corn husk by alkali and bleaching treatments followed by sulfuric acid hydrolysis treatment. The material obtained after each stage of the treatments was characterized. Morphological investigation was carried out using scanning electron microscope (SEM) and transmission electron microscopy (TEM). Fourier transform infrared (FTIR) spectroscopy showed the progressive removal of non-cellulosic materials. The crystallinity of corn husk and CNCs was also investigated using X-ray diffraction analysis (XRD). The highest crystallinity index value of this study is …
Preparation And Characterization Of Epoxidized Natural Rubber And Epoxidized Natural Rubber/Carboxylated Styrene Butadiene Rubber Blends,
2015
Chulalongkorn University
Preparation And Characterization Of Epoxidized Natural Rubber And Epoxidized Natural Rubber/Carboxylated Styrene Butadiene Rubber Blends, Saowaroj Chuayjuljit, Thongchai Nutchapong, Onusa Saravari, Anyaporn Boonmahitthisud
Journal of Metals, Materials and Minerals
In this study, epoxidized natural rubber (ENR) with 30 mol % epoxidation (ENR-30) was first prepared from natural rubber (NR) latex via in situ performic epoxidation using 0.5 M hydrogen peroxide and 0.75 M formic acid at 50C for 4 h. The prepared ENR-30 was blended with three different loadings of carboxylated styrene butadiene rubber (XSBR) (10, 20 and 30 wt%) in the latex stage. All ENR-30/XSBR blends had longer scorch time and cure time than neat ENR-30 as examined on a moving die rheometer. The tensile properties (tensile strength, modulus at 300% strain and elongation at break), thermal stability …
Effect Of Heating Rate On Morphology Of Anti-Reflective Tio2 Film Coated By Sol-Gel With Polyethylene Glycol,
2015
Chulalongkorn University
Effect Of Heating Rate On Morphology Of Anti-Reflective Tio2 Film Coated By Sol-Gel With Polyethylene Glycol, Kumpol Leelaruedee, Patama Visuttipitukul, Niti Yongvanich
Journal of Metals, Materials and Minerals
This research studies formation of thin porous TiO2 film prepared by Sol-gel process with spin coating. Polyethylene glycol with molecular weight of 6,000 g/mol (6kPEG) was used as a pore generating agent. The TiO2 film was calcination at 450C for 1 hour with different heating rate. It was found that heating rate strongly affects on morphology of TiO2 film due to grain coalescence. The lower heating rate tends to cause more coalescence resulting in coarsening of both grain and pore size. With higher heating rate, film density can be increased due to lower number of pores. On the other hand, …
Effect Of Temperature Dropping During Solution Treatment During Rejuvenation Heat Treatment On Final Microstructures In Cast Nickel Base Superalloy, Grade Inconel-738,
2015
Chulalongkorn University
Effect Of Temperature Dropping During Solution Treatment During Rejuvenation Heat Treatment On Final Microstructures In Cast Nickel Base Superalloy, Grade Inconel-738, Aimamorn Promboopha, Sureerat Polsilapa, Panyawat Wangyao
Journal of Metals, Materials and Minerals
Generally, the rejuvenation heat treatment of degraded turbine blades, which were made of cast nickel based superalloy, Grade Inconel 738, usually consist of solution treatment condition with temperature range of 1125C- 1205C for 3 hours and then following with double aging processes, which include primary aging at 1055C for 1 hour and secondary aging at 845C for 24 hours. However, in practical working conditions of reheat treatment processed, the possible change of temperature during solution treatment can be obtained by error or malfunction of heating furnace, which usually provides the temperature dropping down. To simulate this effect, the dropping temperature …
Atom Probe Study Of Irradiation-Enhanced Α′ Precipitation In Neutron-Irradiated Fe–Cr Model Alloys,
2015
Boise State University
Atom Probe Study Of Irradiation-Enhanced Α′ Precipitation In Neutron-Irradiated Fe–Cr Model Alloys, Yaqiao Wu
Materials Science and Engineering Faculty Publications and Presentations
Atom probe tomography (APT) was performed to study the effects of Cr concentrations, irradiation doses and irradiation temperatures on α′ phase formation in Fe–Cr model alloys (10–16 at.%) irradiated at 300 and 450 °C to 0.01, 0.1 and 1 dpa. For 1 dpa specimens, α′ precipitates with an average radius of 1.0–1.3 nm were observed. The precipitate density varied significantly from 1.1 × 1023 to 2.7 × 1024 1/m3, depending on Cr concentrations and irradiation temperatures. The volume fraction of α′ phase in 1 dpa specimens qualitatively agreed with the phase diagram prediction. For 0.01 dpa …
Peroxidase Inhibition Assay For The Detection Of Some Thiols By Carbon Screen Printed Electrodes Based On Square Wave Voltammetry,
2015
Chulalongkorn University
Peroxidase Inhibition Assay For The Detection Of Some Thiols By Carbon Screen Printed Electrodes Based On Square Wave Voltammetry, Wischada Jongmevasna, Orawon Chailapakul, Manchumas Hengsakul Prousoontorn
Journal of Metals, Materials and Minerals
Cassava peroxidase (CSP) from leaves of cultivar KU50 was used as an alternative peroxidase for the electrochemical detection of thiram and thiourea.Square-wave voltammetry (SWV) incorporated with screen-printed carbon electrode was applied for the investigation of peroxidase activity. It was based on the measurement of 3, 3-diaminobenzidine (DAB) electro active product catalyzed by CSP and horseradish peroxidase (HRP) in 0.04 M Britton-Robinson buffer, pH 6, containing urea hydrogen peroxide in 96-well microplate. The reaction mixture in the presence of either thiourea or thiram was performed in order to study their effects on DAB oxidation catalyzed by both peroxidases. From the result …
Sandwich-Type Cobalt Tungstophosphate: Synthesis, Characterization And Catalytic Activity,
2015
Chulalongkorn University
Sandwich-Type Cobalt Tungstophosphate: Synthesis, Characterization And Catalytic Activity, Wimonrat Trakarnpruk, Aphiwat Wannatem, Jutatip Kongpeth
Journal of Metals, Materials and Minerals
odium tungstophosphate, Na9[HPW9O34].7H2O was synthesized by reaction in aqueous solution of sodium tungstate, phosphoric acid and acetic acid. It was used as a precursor for synthesis of sandwich-type cobalt tungstophosphate, K10[Co4(H2O)2(PW9O34)2].20H2O by reacting with cobalt chloride and potassium acetate. The potassium ion can be exchanged with tetrabutylammonium bromide. The characterization was carried out by means of elemental analysis, FT-IR, UV-vis diffuse reflectance spectroscopy (DR-UV-vis). The sandwich-type cobalt tungstophosphate was used to catalyze oxidation of cyclooctane with H2O2 as oxidant in absence and presence of phase transfer agent. The experimental results showed that with phase transfer agent, the sandwich-type cobalt tungstophosphate …
Properties Of Binary And Ternary Composites Of Polypropylene Containing Soybean Oil-G-Chitosan And Hydrophobic Phosphonated Silica,
2015
Chulalongkorn University
Properties Of Binary And Ternary Composites Of Polypropylene Containing Soybean Oil-G-Chitosan And Hydrophobic Phosphonated Silica, Natthaphop Suwannamek, Kawee Srikulkit
Journal of Metals, Materials and Minerals
PP/soybean oil-g-chitosan binary composite, PP/hydrophobic phosphonated silica binary composite, and PP/chitosan/hydrophobic phosphonated silica ternary composite were prepared. Firstly, the preparation of soybean oil-g-chitosan was carried out by surface hydrophobicity modification of chitosan powder with soybean oil maleate and hydrophobicallyphosphonated silica was prepared by silanization of phosphonated silica with hexadecyltrimethoxysilane (an organosilane). Binary and ternary composites were prepared using a twin screw extruder. It was found that soybean oil-g-chitosan not only caused a decrease in tensile strength but also enhanced flexibility of PP due to its plasticization effect. In the opposite direction, the addition of hydrophobic phosphonated silica resulted in an …
An Updated Mineralogical Analysis Of Sediment Materials From Three Therapeutically-Used Peruvian Lagoons,
2015
Chulalongkorn University
An Updated Mineralogical Analysis Of Sediment Materials From Three Therapeutically-Used Peruvian Lagoons, Maria Luisa Ceron Loayza, Jorge Aurelio Bravo Cabrejos, F. A. R. Navarro, F. Urcia Ch.
Journal of Metals, Materials and Minerals
Herein, we determine the elemental, structural and mineralogical characterization of samples collected in three Peruvian lagoons; likewise, we investigate the physical and chemical properties of their fractions, both clay and magnetic. These lagoons are located in the Chilca District, Cate Province, southern Lima Region, Peru; their morphology has been altered since we carried out a previous study five years ago. The physical analytical techniques we used were energy dispersive X-ray fluorescence (EDXRF); X-ray diffractometry (XRD); and transmission Msbauer spectroscopy (TMS), at room and liquid-helium temperatures, and at low and high velocities. The results indicate that dolomite is the main clayey …
Triboelectric Solar Generator Concept And Experimental Research,
2015
Old Dominion University
Triboelectric Solar Generator Concept And Experimental Research, Elias Yazdanshenas
Mechanical & Aerospace Engineering Theses & Dissertations
In this thesis, a novel concept, a triboelectric solar generator (TSG ), is proposed for generation of high voltage direct current (HVDC) electricity from solar radiation. An experimental investigation was conducted to prove the concepts of charge generation through the triboelectric effect and charge transmission using semiconductors. The triboelectric effect, also known as the contact electrification, is a well-known physical phenomenon that electrostatic charges are generated by rubbing dissimilar materials. However, traditional triboelectric generators had never been commercialized due to their poor power output. Physically, it is due to the difficulty of charge transmission from insulators, which generate charges. The …
Inert-Gas Condensed Co–W Nanoclusters: Formation, Structure And Magnetic Properties,
2015
University of Nebraska-Lincoln
Inert-Gas Condensed Co–W Nanoclusters: Formation, Structure And Magnetic Properties, Farhad Reza Golkar-Fard
Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research
Rare-earth permanent magnets are used extensively in numerous technical applications, e.g. wind turbines, audio speakers, and hybrid/electric vehicles. The demand and production of rare-earth permanent magnets in the world has in the past decades increased significantly. However, the decrease in export of rare-earth elements from China in recent time has led to a renewed interest in developing rare-earth free permanent magnets. Elements such as Fe and Co have potential, due to their high magnetization, to be used as hosts in rare-earth free permanent magnets but a major challenge is to increase their magnetocrystalline anisotropy constant, K1, which largely …
Investigation Of Electrical And Magneto Transport Properties Of Reduced Graphene Oxide Thin Films,
2015
Missouri State University
Investigation Of Electrical And Magneto Transport Properties Of Reduced Graphene Oxide Thin Films, Ariful Haque
Graduate Theses/Dissertations
Large area uniform thin films of reduced graphene oxide (RGO) was synthesized by pulsed laser deposition (PLD) technique. A number of structural properties including the defect density, average size of sp2 clusters, and degree of reduction were investigated by Raman spectroscopy and X-ray diffraction (XRD) analysis. The temperature dependent (5K - 350K) four terminal electrical transport property measurement confirms variable range hopping and thermally activated transport mechanism of the charge carriers at low (5K - 210K) and high temperature (210K - 350K) regions, respectively. The calculated localization length, density of states (DOS) near Fermi level (EF), hopping energy, and Arrhenius …
Design Of High Temperature Evaporator For Spectroscopic Study Of Equilibrated Vapor Phase Materials,
2015
Missouri State University
Design Of High Temperature Evaporator For Spectroscopic Study Of Equilibrated Vapor Phase Materials, Yarden Bosch
Graduate Theses/Dissertations
This work details the design, assembly, and testing of a high temperature electron beam evaporator for equilibrated vapor phase evaporation of rock oxides for the purpose of astrophysical characterization of extrasolar planetary atmospheres. Infrared spectroscopy of high temperature SiO2 atmosphere created through the electron beam evaporation technique and trapped by argon ice matrix isolation was performed to generate a reference spectrum against which absorption lines in stellar spectra taken during planetary transits can be compared. Studies demonstrate that water inclusions in milky quartz (SiO2) can be used to create H2O/SiO2 equilibrated atmospheres within a Knudsen cell. Modeling of exoplanet spectra …
Electromagnetic Induction By Ferrofluid In An Oscillating Heating Pipe,
2015
Mississippi State University
Electromagnetic Induction By Ferrofluid In An Oscillating Heating Pipe, John Gabriel Monroe, Erick S. Vasquez, Zachary S. Aspin, Keisha B. Walters, Matthew J. Berg, Scott M. Thompson
Chemical and Materials Engineering Faculty Publications
No abstract provided.
Current Status And Prospect Of Cathode Materials For Lithium Sulfur Batteries,
2015
Department of Chemistry, Institute of New Energy, Fudan University, Shanghai 200438, China;
Current Status And Prospect Of Cathode Materials For Lithium Sulfur Batteries, Lan Zhou, Ai-Shui Yu
Journal of Electrochemistry
Elemental sulfur has been extensively investigated as a promising candidate of cathode material for next generation lithium secondary batteries. However, some troublesome issues, such as the low electric conductivity of sulfur (5×10-30 S·cm-1) and the high solubility of lithium polysulfide intermediates in organic electrolytes, resulting in a low utilization of active material and a redox shuttling of dissolved polysulfide ions between the sulfur cathode and the lithium anode, which eventually leads to a deposition of insoluble and insulating Li2S2/Li2S on the electrode surface and a fast reduction in the specific capacity. …
Research Status And Application Prospects Of Limnpo4 As A New Generation Cathode Material For Lithium-Ion Batteries,
2015
Advanced Li-ion Battery Engineering Lab, Ningbo Institute of Materials Technology Engineering (NIMTE), Chinese Academy of Sciences, Ningbo 315201, Zhejing, China;
Research Status And Application Prospects Of Limnpo4 As A New Generation Cathode Material For Lithium-Ion Batteries, Lai-Fen Qin, Yong-Gao Xia, Li-Peng Chen, Hua-Sheng Hu, Feng Xiao, Zhao-Ping Liu
Journal of Electrochemistry
Olivine-structured lithium manganese phosphate (LiMnPO4) has the following advantages: excellent thermal stability, low cost, high safety and environmental benignity. Importantly, the theoretical energy density of LiMnPO4 is about 20% higher than that of commercialized LiFePO4 due to its higher Li+ intercalation potential of 4.1 V (vs. Li+/Li). Moreover, the high operating voltage of LiMnPO4 is compatible with present non-aqueous organic electrolytes of lithium-ion batteries. Therefore, LiMnPO4 is considered as a next generation cathode material for lithium-ion batteries. However, LiMnPO4 suffers from poor electronic conductivity and low lithium diffusivity, resulting in …
Preparations And Applications Of Layered Carbon And Layered Carbon-Pbso4 Composite,
2015
University of Science and Technology Beijing, Beijing 100083, China;
Preparations And Applications Of Layered Carbon And Layered Carbon-Pbso4 Composite, Shu-Kai Zhang, Hao Zhang, Wei-Hua Xue, Jie Cheng, Wen-Feng Zhang, Gao-Ping Cao, Hai-Lei Zhao, Yu-Sheng Yang
Journal of Electrochemistry
The layered carbon materials (similar to graphene) have been synthesized by chemical vapor deposition (CVD) on the cheap catalyst (potassium or sodium carbonate substrate). The layered-carbon- lead sulfate (PbSO4) composite could be prepared by in situ chemical deposition based on the layered carbon. The XRD, SEM and TEM results showed that the layered carbon materials was amorphous carbon layer, and the composite was a compound made of fine lead sulfate grains and layered carbon. Thermogravimetric analysis determined the carbon content in the composite. Adding a certain amount of layered carbon or layered-carbon-PbSO4 composite into negative active materials …
Electrochemical Mass Spectrometric Study Of Lithium-Oxygen Batteries,
2015
State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin 130022, China;
Electrochemical Mass Spectrometric Study Of Lithium-Oxygen Batteries, Xin-Xiu Yan, Li-Po Ma, Zhang-Quan Peng
Journal of Electrochemistry
Mass Spectrometry, coupled with electrochemistry, is a powerful research tool to study mechanisms for a broad range of electrode reactions by identifying and quantifying reaction products and intermediates. In this review, we summarize the recent advances in the Li-O2 battery researches offered by electrochemical mass spectrometry based on our group investigations. These include the research progresses in electrolytes, cathode materials (electrocatalysts), and parasitic reactions, i.e., the key issues associated with Li-O2 research. In addition, we also discuss the effects of irreversible side reactions involved in battery systems on charge and discharge processes.
Synthesis Of Graphene Wrapped Li-Rich Layered Metal Oxide And Its Electrochemical Performance,
2015
Department of Chemistry, Fudan University, Shanghai 200433, China;
Synthesis Of Graphene Wrapped Li-Rich Layered Metal Oxide And Its Electrochemical Performance, Meng-Yan Hou, Ke Wang, Xiao-Li Dong, Yong-Yao Xia
Journal of Electrochemistry
In present work, lithium-rich layered transition metal oxide (LLO) was synthesized by a co-precipitation method in combination with a solid-state reaction. The graphene wrapped Li-rich layered oxide composite (LLO/Gra) was obtained by sintering the LLO/GO composite at 300 oC for 30 min in an air. The morphologies and the electrochemical performances were characterized by means of SEM, TEM, XRD, XPS, EIS and charge/discharge tests. The results indicated that the LLOe particles were uniformly wrapped with graphene. The resulting material exhibited better rate capability than that of pristine LLO since the wrapped graphene demonstrated the enhanced electronic conductivity. Accordingly, the …
