Overview Of Instruments For Investigating Dust Interactions On Small Solar System Bodies By Landers And Rovers,
2014
Massachusetts Institute of Technology
Overview Of Instruments For Investigating Dust Interactions On Small Solar System Bodies By Landers And Rovers, Ryan L. Kobrick, Jeffrey A. Hoffman, Kenneth W. Street Jr., Douglas L. Rickman
Publications
Small Solar System bodies such as asteroids, comets and Mars' moons Phobos and Deimos have relatively unknown regolith environments. It is hypothesized that dust preserved in the regolith on the surfaces will have similar mechanical properties to lunar dust because of similar formation processes from micrometeoric bombardment, low relative gravity for slow settling times, and virtually no weathering because there is no atmosphere.
Nickel Aluminum Shape Memory Alloys Via Molecular Dynamics,
2014
Purdue University
Nickel Aluminum Shape Memory Alloys Via Molecular Dynamics, Keith Ryan Morrison
Open Access Theses
Shape memory materials are an important class of active materials with a wide range of applications in the aerospace, biomedical, and automobile industries. These materials exhibit the two unique properties of shape memory and superelasticity. Shape memory is the ability to recover its original shape by applying heat after undergoing large deformations. Superelasticity is the ability to undergo large, reversible deformations (up to 10%) that revert back when the load is removed. These special properties originate from a reversible, diffusionless solid-solid phase transformation that occurs between a high temperature austenite phase and a low temperature martensite phase. The development of …
Preparation & Characterization Of High Purity Cu2 Znsn(Sxse1-X)4 Nanoparticles,
2014
Purdue University
Preparation & Characterization Of High Purity Cu2 Znsn(Sxse1-X)4 Nanoparticles, Bethlehem G. Negash
Open Access Theses
Research in thin film solar cells applies novel techniques to synthesize cost effective and highly efficient absorber materials in order to generate electricity directly from solar energy. Of these materials, copper zinc tin sulfoselenide (Cu2ZnSn(SxSe1-x) 4) nanoparticles have shown great promise in solar cell applications due to optimal material properties as well as low cost & relative abundance of materials.1,2 Sulfoselenide nanoparticles have also a broader impact in other industries including electronics3, LED 4, and biomedical research5. Of the many routes of manufacturing these class of semiconductors, …
Correlating Grain Size To Radiation Damage Tolerance Of Tungsten Materials Exposed To Relevant Fusion Conditions,
2014
Purdue University
Correlating Grain Size To Radiation Damage Tolerance Of Tungsten Materials Exposed To Relevant Fusion Conditions, Sean Robert Gonderman
Open Access Theses
Tungsten remains a leading candidate for plasma facing component (PFC) in future fusion devices. This is in large part due to its strong thermal and mechanical properties. The ITER project has already chosen to use an all tungsten divertor. Despite having a high melting temperature and low erosion rate, tungsten faces a large variety of issues when subject to fusion like conditions. These include embrittlement, melting, and extreme morphology change (growth of fuzz nanostructure). The work presented here investigates mechanisms that drive surface morphology change in tungsten materials exposed to fusion relevant plasmas. Specifically, tungsten materials of different grain sizes …
Technology, Science, And Environtmental Impact Of A Novel Cu-Ag Core-Shell Solderless Interconnect System,
2014
Purdue University
Technology, Science, And Environtmental Impact Of A Novel Cu-Ag Core-Shell Solderless Interconnect System, Milea Joy Kammer
Open Access Dissertations
Tin-based solder is ubiquitous in microelectronics manufacturing and plays a critical role in electronic packaging and attachment. While manufacturers of consumer electronics have made the transition to the use of lead-free solder, there are still a variety of reliability issues associated with these lead-free alternatives, particularly for high performance, high reliability applications. Because of these performance short-comings, researchers are still searching for a material, an alloy, or a unique alternative that can meet the thermal, mechanical, and electrical requirements for conventional reflow solder applications. In an effort to produce a more reliable alternative, Kim et al. proposed the low-temperature (200°C) …
Synthesis And Characterization Of Amorphous Silica Nanoparitcles From Aqueous Silicates Uisng Cationic Surfactants,
2014
Chulalongkorn University
Synthesis And Characterization Of Amorphous Silica Nanoparitcles From Aqueous Silicates Uisng Cationic Surfactants, M Abou Rida, F Harb
Journal of Metals, Materials and Minerals
In this work amorphous silica was synthesized using sodium silicate and hydrochloric acid by precipitation according to St?ber method. A system of chemical reactions has been developed which permits the controlled growth of silica particles using two different cationic surfactants as the dispersing agents. These surfactants were cetyltrimethylammonium bromide [CTAB] and dodecyltrimethylammonium bromide [DTAB]. The synthesized silicas were characterized by using X-ray diffraction (XRD), Infrared Spectroscopy (IR), Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDX) and Dynamic light scattering (DLS). Addition of a dispersing agent in the reaction reduced the particle size of the silica produced. The average size of …
Property Enhancement Of Polybenzoxazine Modified With Maleic Anhydride,
2014
Chulalongkorn University
Property Enhancement Of Polybenzoxazine Modified With Maleic Anhydride, W Punuch, M Okhawilai, S Rimdusit
Journal of Metals, Materials and Minerals
One seemingly shortcoming of polybenzoxazine is its relatively high rigidity. Therefore, various efforts have been attempted to toughen polybenzoxazine such as by alloying with more flexible monomers or polymers e.g. urethane elastomers or flexible epoxy. The alloying of polybenzoxazine with those resins or polymers has been reported to show synergy in some properties thus economically provide a novel class of resin systems with superior performance. In this work, polybenzoxazine alloys were prepared from bisphenol-A-aniline based benzoxazine resin (BA-a) and maleic anhydride (MA) in N, N-Dimethyformamide (DMF) solvent. The miscible monomer mixture was easily transformed into transparent polymer alloys by thermal …
Effects Of The Tempering On Mechanical Properties Of Dual Phase Steels,
2014
Chulalongkorn University
Effects Of The Tempering On Mechanical Properties Of Dual Phase Steels, T Sirinakorn, V Uthaisangsuk, S Srimanosaowapak
Journal of Metals, Materials and Minerals
Dual Phase (DP) steels have been gradually used in the automotive industries because of their distinguished strength and ductility properties. Principally, microstructure of the DP steels contains defined amount of hard martensite islands dispersed in soft ferrite matrix. This microstructure characteristic and corresponding mechanical properties of the DP steels can be adjusted by heat treatment. In this work, effects of tempering temperature and time on tensile properties of DP steels were investigated. Continuous yielding behavior of tempered DP steels was observed up to around a temperature of 300C. At higher tempering temperature, DP steels showed distinct increased yield point. Furthermore, …
Corrosion Study On Low Alloy High Phosphorus Steel,
2014
Chulalongkorn University
Corrosion Study On Low Alloy High Phosphorus Steel, B K. Jena, N Gupta, B Singh, G Sahoo
Journal of Metals, Materials and Minerals
The effect of P on corrosion behaviour of low alloy steels exposed for one month cyclic wet/dry salt spray was investigated and compared with low carbon steel. Electrochemical Impedance Spectroscopy (EIS) results revealed that the rust resistance (Rrust) increased with the number of salt spray test cycles. The higher phosphorus content steel (G12) exhibited higher rust resistance (Rrust) than that of low phosphorus content steels (SCR & G11), while similar corrosion rate was noticed from the Tafel extrapolation study in 3.5% NaCl solution for all the test samples. All steels revealed ferrite pearlite microstructure. The larger ferrite grain of G12 …
Shape Fixity And Shape Recovery Characteristics Of Aliphatic Epoxy-Benzoxazine Shape Memory Polymer,
2014
Chulalongkorn University
Shape Fixity And Shape Recovery Characteristics Of Aliphatic Epoxy-Benzoxazine Shape Memory Polymer, T Tanpitaksit, M Okhawilai, S Rimdusit
Journal of Metals, Materials and Minerals
Shape memory polymers (SMPs) are polymers that can fix the temporary shape and recover to the permanent shape by external stimuli. Epoxy resins are an important family of SMPs due to their excellent stability, thermomechanical endurance and the high values of shape fixity. However, epoxide ring opening polymerization required a curing agent which possesses some disadvantages such as high cost, toxic problem to the user and corrosion to the processing apparatus. In this research, novel series of SMPs were prepared from aliphatic epoxy as soft segment and benzoxazine resin (BA-a) as hard segment. Additionally, benzoxazine resin can also function as …
Agronomic Benefits Of Durian Shell Biochar,
2014
Chulalongkorn University
Agronomic Benefits Of Durian Shell Biochar, N Prakongkep, R J. Gilkes, W Wiriyakitnateekul
Journal of Metals, Materials and Minerals
This study investigated the chemical properties of durian shell biochar which is used as a soil amendment. It can act as a carbon sink and as a means to improve crop yield. Plant nutrient elements in this biochar are in crystalline minerals located within the complex pore structure therefore biochar production from wastes could be a very good way to reduce demand for fertilizers. XRD and SEM-EDS results demonstrate that the numerous minerals in biochar are highly soluble, such as archerite (KH2PO4), chlorocalcite (KCaCl3), kalicinite (KHCO3), and sylvite (KCl) with small amounts …
Development Of Electronic Packages From Polypropylene/Ethylene Propylene Rubber Blends: A Double Percolation Approach,
2014
Chulalongkorn University
Development Of Electronic Packages From Polypropylene/Ethylene Propylene Rubber Blends: A Double Percolation Approach, S Phromdee, P Lorjai, S Tiptipakorn, S Rimdusit
Journal of Metals, Materials and Minerals
Volume resistivity of less than 104 W.cm is required for typical electrically conductive packages. Conductive polypropylene (PP) packages with the above level of conductivity value can be achieved by a use of carbon black (CB) as conductive filler. To maintain processability of PP with low cost, minimal amount of carbon black is preferable in the conductive composites. By introducing a second polymer with immiscible or partially miscible nature to the first polymer, and if the conductive filler is localized in one polymer phase, a system of double percolation with minimal filler content can be achieved. In this work, electrically conductive …
Modulating Notochordal Differentiation Of Human Induced Pluripotent Stem Cells Using Natural Nucleus Pulposus Tissue Matrix,
2014
Missouri University of Science and Technology
Modulating Notochordal Differentiation Of Human Induced Pluripotent Stem Cells Using Natural Nucleus Pulposus Tissue Matrix, Yongxing Liu, M. N. Rahaman, B. Sonny Bal
Materials Science and Engineering Faculty Research & Creative Works
Human induced pluripotent stem cells (hiPSCs) can differentiate into notochordal cell (NC)-like cells when cultured in the presence of natural porcine nucleus pulposus (NP) tissue matrix. The method promises massive production of high-quality, functional cells to treat degenerative intervertebral discs (IVDs). Based on our previous work, we further examined the effect of cell-NP matrix contact and culture medium on the differentiation, and further assessed the functional differentiation ability of the generated NC-like. The study showed that direct contact between hiPSCs and NP matrix can promote the differentiation yield, whilst both the contact and non-contact cultures can generate functional NC-like cells. …
An Investigation Of The Effect Of Direct Metal Deposition Parameters On The Characteristics Of The Deposited Layers,
2014
Missouri University of Science and Technology
An Investigation Of The Effect Of Direct Metal Deposition Parameters On The Characteristics Of The Deposited Layers, Tarak A. Amine, Joseph William Newkirk, Frank W. Liou
Materials Science and Engineering Faculty Research & Creative Works
Multilayer direct laser deposition (DLD) is a fabrication process through which parts are fabricated by creating a molten pool into which metal powder is injected as particles. During fabrication, complex thermal activity occurs in different regions of the build; for example, newly deposited layers will reheat previously deposited layers. The objective of this study was to provide insight into the thermal activity that occurs during the DLD process. This work focused on the effect of the laser parameters of newly deposited layers on the microstructure and mechanical properties of the previously deposited layers in order to characterize these effects to …
Synthesis And Characterization Of Cdse/Zns Core/Shell Quantum Dot Sensitized Pcpdtbt-P3ht:Pcbm Organic Photovoltaics,
2014
California Polytechnic State University, San Luis Obispo
Synthesis And Characterization Of Cdse/Zns Core/Shell Quantum Dot Sensitized Pcpdtbt-P3ht:Pcbm Organic Photovoltaics, Buddy J. Bump
Master's Theses
Durable, cheap, and lightweight polymer based solar cells are needed, if simply to meet the demand for decentralized electrical power production in traditionally “off-grid” areas. Using a blend of Poly(3-hexylthiophene-2,5-diyl) (P3HT), Phenyl-C61-butyric acid methyl ester (PCBM), and the low band-gap polymer Poly[2,6-(4,4-bis-(2- ethylhexyl)-4H-cyclopenta [2,1-b;3,4-b′]dithiophene)-alt-4,7(2,1,3-benzothiadiazole)] (PCPDTBT), we have fabricated devices with a wide spectral response and 3% power conversion efficiency in AM 1.5 conditions; however, this thin film system exhibits only 0.43 optical density at 500 nm. To improve the performance of this polymer blend photovoltaic, we aim to increase absorption by adding CdSe(ZnS) core (shell) quantum dots. Four groups of …
Preparation And Characterizations Of Highly Filled Graphene-Polybenzoxazine Composites,
2014
Chulalongkorn University
Preparation And Characterizations Of Highly Filled Graphene-Polybenzoxazine Composites, R Plengudomkit, M Okhawilai, S Rimdusit
Journal of Metals, Materials and Minerals
In recent years, graphene has been extensively utilized in electronic applications due to its superior electrical conductivity, high thermal conductivity and excellent mechanical properties [1, 2]. This research emphasized on the development of graphene (xGnP Grade H, XG Science, USA) filled composites based on polybenzoxazine particularly at high graphene loading (0-60wt%) [3, 4]. It was found that the density of the obtained composites was linearly increased with graphene content and the values were determined to be 1.185-1.637 g/cm3 which followed the rule of mixture suggesting negligible void in the composites samples. Mechanical and thermal properties of the graphene filled polybenzoxazine …
Monoclinic Phases Arising Across Thermal Inter-Ferroelectric Phase Transitions,
2014
Missouri University of Science and Technology
Monoclinic Phases Arising Across Thermal Inter-Ferroelectric Phase Transitions, Yijia Gu, Fei Xue, Shiming Lei, Tom T. A. Lummen, Jianjun Wang, For Full List Of Authors, See Publisher's Website.
Materials Science and Engineering Faculty Research & Creative Works
Thermotropic phase boundaries (TPBs), as thermal analogs of morphotropic phase boundaries (MPBs), are associated with the thermal inter-ferroelectric phase transitions. Similar to an MPB, a TPB exhibits a characteristically flattened energy profile which favors polarization rotation, thus giving rise to a structurally bridging low-symmetry phase. We report on the kinetic process of thermal inter-ferroelectric phase transitions in BaTiO3 and KNbO3 using the phase-field method. The domain structures are found to play key roles in stabilizing the monoclinic phase. In simple domain structures, the monoclinic phase is a transient phase and cannot be stabilized into its neighboring phase regimes. …
A New Silver Electrode Based On The Composite Silver Sulfide/Attapulgite As Ionophore,
2014
Department of Chemistry and Material Science, Nanjing Forestry University, Nanjing 210037, China;
A New Silver Electrode Based On The Composite Silver Sulfide/Attapulgite As Ionophore, Wen-Zhuo Li, Ding-Jia Xu, Jun Wang, Jian-Long Wang
Journal of Electrochemistry
A novel silver ion selective electrode with its ionophore being a kind of organic/inorganic composite composed of silver sulfide and attapulgite has been prepared. Attapulgite is a type of natural inorganic polymer which has some properties similar to zeolite, such as a higher specific surface area and plenty of intercrystalline cavities. In this work, the silver ions were firstly adosrbed in the micropores of the attapulgite, then thioacetamidetiny was selected to mix with the prepared silver ions/ attapulgite composite. Owning to the existence of sulfur atoms in the structure of thioacetamide molecules, thioacetamide molecules can react with the silver ions/attapulgite …
Surface Enhanced Raman Spectroscopic Studies Of Pyridine Adsorbed On Ti/Au@Sio2 Film Electrode,
2014
Soochow University
Surface Enhanced Raman Spectroscopic Studies Of Pyridine Adsorbed On Ti/Au@Sio2 Film Electrode, Min-Min Xu, Ke Liu, Qing-Hua Guo, Jian-Lin Yao
Journal of Electrochemistry
This study was performed based on shell-isolated nanoparticles-enhanced Raman spectroscopy (SHINERS) technology. The Au@SiO2 nanoparticles were prepared and characterized by TEM and cyclic voltammetry. It was shown that the shell of SiO2 was compact. The high quality signal measured by surface enhanced Raman spectroscopy (SERS) was obtained from the adsorbed pyridine on Ti/Au@SiO2 electrode. The origin of the SERS signals was further confirmed by testing Pt and Ni electrodes. In addition, potential dependent adsorption behavior was investigated. It was found that pyridine was adsorbed parallel on the surface from -0.1 V to -0.6 V, and converted to …
Horseradish Peroxidase-Attapulgite Clay Nanocomposites: Fabrication And Application To Sensing The Extracellular H2O2 Released From Cells,
2014
Jiangsu Key Laboratory of New Power Batteries, College of Chemistry and Materials Science, Nanjing Normal University, Nanjing 210046, China;
Horseradish Peroxidase-Attapulgite Clay Nanocomposites: Fabrication And Application To Sensing The Extracellular H2O2 Released From Cells, Ping Wu, Chen-Xin Cai
Journal of Electrochemistry
The nanostructured attapulgite clay was employed as a support matrix for immobilizing horseradish peroxidase (HRP). FTIR and electrochemical methods demonstrated that HRP had been effectively assembled on attapulgite surface with the formation of HRP-attapulgite nanocomposites. The HRP-attapulgite hybrid was deposited on the glassy carbon (GC) electrode forming the HRP-attapulgite/GC electrode. Cyclic voltammetric results showed a pair of well-defined redox peaks, which were ascribed to direct electron transfer (DET) of HRP, with the formal potential E0′ = -335 mV (vs. SCE) in the phosphate buffer solution (PBS, pH 7.0). The dependence of E0′ on solution pH indicated …
