Nanofibers of aluminum oxide
Nafen is a new material consisting of aluminum oxide nanofibers with gamma and chi crystal phases. It has fiber diameters of 7-10 nm or 30-40 nm, lengths up to 150 mm, and a specific surface area of 155 m2/g. Nafen is produced via a continuous process that yields over 0.5 kg/hour. TEM images show the fine fiber structure and high length-to-diameter ratio. The fibers are co-aligned in blocks up to 50x50x15 cm with a bulk density of 0.1-0.4 g/cm3. Analysis confirms the gamma and chi phases of polycrystalline
1990 crystallization kinetics of thin amorphous in sb filmspmloscholte
1) Evaporated and sputtered InSb films have different crystallization properties. Evaporated films have a lower activation energy of 1.39 eV and crystallize by three-dimensional growth on existing nuclei.
2) Sputtered films have a higher activation energy of 2.7 eV and crystallize by nucleation and subsequent growth on the nuclei. The Avrami exponent indicates sputtered films require crystalline nuclei to form before crystallization can begin.
3) Transmission electron microscopy images show evaporated films have existing nuclei while sputtered films have no visible crystallites in the as-deposited state, requiring nucleation.
The document describes methods for improving X-ray contrast of phases in porous rock samples using micro-CT imaging and image processing. Heavy metal ions are used to enhance the contrast of ice and clays. A Bruker micro-CT scanner with cooling stage is used to image ice-saturated rock samples. Image segmentation software Avizo Fire is applied to separate phases and calculate properties like porosity, permeability, and pore size distribution from the 3D digital models.
This document discusses the application of carbon nanotubes in plastics. It describes how carbon nanotubes have extraordinary mechanical and thermal properties like high strength, stiffness, and thermal conductivity. It then explains how Bayer MaterialScience produces multi-walled carbon nanotube agglomerates called Baytubes through a catalytic chemical vapor deposition process at large scale. These Baytubes have very high purity and can enable new applications in conductive polymers, composites, coatings and other materials.
1. Porous hollow SnO2 nanofibers were fabricated by annealing electrospun polyvinylpyrrolidone (PVP)/Sn precursor composite nanofibers.
2. The formation mechanism involves a core-shell structure forming during electrospinning due to solvent evaporation. PVP then decomposes during annealing, acting as a sacrificial template to maintain the fibrous structure.
3. A Kirkendall effect and concentration gradient lead to hollow fiber formation as Sn precursor diffuses outward and SnO2 forms on the surface via surface diffusion, leaving a hollow core.
The document summarizes the synthesis, characterization, and AC conductivity of nickel-doped magnesium ferrite. Key findings include:
1) Magnesium nickel ferrites were synthesized via a sol gel technique and sintered at 1473 K. X-ray diffraction analysis revealed the presence of a nickel oxide phase along with the ferrite phase, indicating an almost stoichiometric (Mg,Ni)-ferrite phase was obtained.
2) Scanning electron microscopy images showed the (MgNi) ferrite had a regular, granular structure with well-connected grains and an average grain size of 0.7 micrometers.
3) The AC conductivity of the magnesium nickel ferrite increased with increasing frequency
This document discusses different types of column choices for liquid chromatography. It covers silica surface chemistry and characteristics, column particle sizes, pore sizes, bonding procedures, and how these factors impact chromatographic performance. Smaller particle sizes below 2 microns provide higher efficiency with over 30,000 plates per 15 cm column. Pore sizes of 60-80 angstroms are recommended for small molecules below 4000 MW while 95-300 angstrom pores are suitable for larger biomolecules. Column chemistry variations like monomeric versus polymeric bonding and carbon load also impact selectivity and stability. Highly purified Zorbax Rx-silica improves peak shape compared to more acidic silica.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
1990 crystallization kinetics of thin amorphous in sb filmspmloscholte
1) Evaporated and sputtered InSb films have different crystallization properties. Evaporated films have a lower activation energy of 1.39 eV and crystallize by three-dimensional growth on existing nuclei.
2) Sputtered films have a higher activation energy of 2.7 eV and crystallize by nucleation and subsequent growth on the nuclei. The Avrami exponent indicates sputtered films require crystalline nuclei to form before crystallization can begin.
3) Transmission electron microscopy images show evaporated films have existing nuclei while sputtered films have no visible crystallites in the as-deposited state, requiring nucleation.
The document describes methods for improving X-ray contrast of phases in porous rock samples using micro-CT imaging and image processing. Heavy metal ions are used to enhance the contrast of ice and clays. A Bruker micro-CT scanner with cooling stage is used to image ice-saturated rock samples. Image segmentation software Avizo Fire is applied to separate phases and calculate properties like porosity, permeability, and pore size distribution from the 3D digital models.
This document discusses the application of carbon nanotubes in plastics. It describes how carbon nanotubes have extraordinary mechanical and thermal properties like high strength, stiffness, and thermal conductivity. It then explains how Bayer MaterialScience produces multi-walled carbon nanotube agglomerates called Baytubes through a catalytic chemical vapor deposition process at large scale. These Baytubes have very high purity and can enable new applications in conductive polymers, composites, coatings and other materials.
1. Porous hollow SnO2 nanofibers were fabricated by annealing electrospun polyvinylpyrrolidone (PVP)/Sn precursor composite nanofibers.
2. The formation mechanism involves a core-shell structure forming during electrospinning due to solvent evaporation. PVP then decomposes during annealing, acting as a sacrificial template to maintain the fibrous structure.
3. A Kirkendall effect and concentration gradient lead to hollow fiber formation as Sn precursor diffuses outward and SnO2 forms on the surface via surface diffusion, leaving a hollow core.
The document summarizes the synthesis, characterization, and AC conductivity of nickel-doped magnesium ferrite. Key findings include:
1) Magnesium nickel ferrites were synthesized via a sol gel technique and sintered at 1473 K. X-ray diffraction analysis revealed the presence of a nickel oxide phase along with the ferrite phase, indicating an almost stoichiometric (Mg,Ni)-ferrite phase was obtained.
2) Scanning electron microscopy images showed the (MgNi) ferrite had a regular, granular structure with well-connected grains and an average grain size of 0.7 micrometers.
3) The AC conductivity of the magnesium nickel ferrite increased with increasing frequency
This document discusses different types of column choices for liquid chromatography. It covers silica surface chemistry and characteristics, column particle sizes, pore sizes, bonding procedures, and how these factors impact chromatographic performance. Smaller particle sizes below 2 microns provide higher efficiency with over 30,000 plates per 15 cm column. Pore sizes of 60-80 angstroms are recommended for small molecules below 4000 MW while 95-300 angstrom pores are suitable for larger biomolecules. Column chemistry variations like monomeric versus polymeric bonding and carbon load also impact selectivity and stability. Highly purified Zorbax Rx-silica improves peak shape compared to more acidic silica.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
This document outlines a study on producing nitrogen enriched carbon coated graphene scaffolds for use in supercapacitors. Graphene oxide was synthesized using a modified Hummer's method and then reduced to produce reduced graphene oxide. Some samples were further modified by enriching with nitrogen and coating with carbon from glucose. Characterization with SEM, UV spectroscopy and cyclic voltammetry showed the nitrogen enriched carbon coated reduced graphene oxide had higher porosity, lower oxygen content and higher specific capacitance, making it a promising electrode material for capacitive energy storage.
The document summarizes research on reinforcing metals and polymers with graphene. Graphene has desirable properties including high strength and conductivity. The researchers produced aluminum-graphene and PDMS-graphene composites using powder metallurgy and solvent mixing. Tensile tests showed the composites had higher strength and flexibility than the base materials alone. Further work is needed to fully characterize the composites and explore applications like microfluidics.
The document summarizes two methods for synthesizing nanostructured ceramic powders: the mimic alkoxide method and hydrothermal synthesis.
The mimic alkoxide method involves dissolving a cerium precursor in alcohol and adding it dropwise to a precipitating solution, producing nanocrystalline powder with primary particles around 15nm that are well-sintered at lower temperatures than aqueous precipitation.
Hydrothermal synthesis uses high-temperature high-pressure water to precipitate oxides from precursor solutions, producing crystalline anhydrous powder without needing calcination or milling, and employing inexpensive raw materials. It is highlighted for making solid-solution particles for multilayer ceramic capacitors.
This document reports on a study of the photophysical and electroluminescent properties of a conjugated-nonconjugated multi-block copolymer. Time-resolved fluorescence experiments and comparisons of solution and solid state fluorescence indicate that in the solid state, emission comes from associated species like ground state dimers or excimers, rather than isolated chromophores. Absorption, fluorescence, FTIR and NMR spectroscopy were used to characterize the materials. Light-emitting diodes were fabricated using the copolymer to study its electroluminescent properties.
The document discusses several methods for determining the size of fine powder particles, including:
1. Calculating mean diameter based on measurements of individual particle sizes and accounting for polydispersity.
2. Using scanning electron microscopy and transmission electron microscopy to directly measure particle sizes.
3. Employing sedimentation techniques like photo-sedimentation and X-ray sedimentation, based on Stokes' equations, to determine particle size distributions.
4. Analyzing particle shapes using flow-based systems that inject a thin, monolayered stream of particles into a flow cell for microscopic imaging and size calculations.
The document summarizes key aspects of low-temperature co-fired ceramic (LTCC) technology for applications in radio frequency (RF) modules. It discusses how LTCC enables miniaturization through multi-layer integration at lower costs than other technologies like thin film. Specific advantages highlighted include high density packaging, parallel processing for shorter development times, design flexibility through buried passive components, and compatibility with various conductors and materials for resistors and capacitors suitable for co-firing. Process details covered include via formation, conductor printing, lamination, and sintering around 850°C to enable silver electrodes. Example applications and performance metrics are also summarized.
Anomalous Behavior Of SSPC In Highly Crystallized Undoped Microcrystalline Si...Sanjay Ram
Microcrystalline silicon is a heterogenous material. We show that different effective DOS distribution can be possible for micro-structurally different μc--Si:H thin films
This document summarizes a study on the effect of atomic layer deposited (ALD) Al2O3 barrier layers of varying thicknesses on forward electron injection from Ru(dcbpy)2(NCS)2 dye to nanocrystalline TiO2 films. Transient absorption spectroscopy showed that a single ALD cycle producing a 1 Å Al2O3 layer decreased singlet electron injection, while more than two cycles also slowed triplet injection. The findings indicate that Al2O3 barriers suppress total electron injection by weakening electronic coupling between the dye and TiO2 and modifying the TiO2 electronic structure. ALD allows precise control of barrier thickness and uniform coverage, making it superior to sol-gel methods for this application.
This document summarizes research on synthesizing and analyzing yttrium-doped barium cerate (BCY) thin films for use as a proton-conducting electrolyte in solid oxide fuel cells. Key points discussed include:
1. BCY films were deposited via spray pyrolysis onto alumina substrates and analyzed using thermo gravimetric analysis, XRD, and SEM to study crystallinity and morphology.
2. XRD and conductivity results showed the films achieved phase-pure and dense structures when annealed at 900°C, with maximum conductivity of 2.45 × 10−3 S cm−1 at 600°C in argon atmosphere.
3. The results indicate spray pyro
Screen printing is a process that involves transferring ink through a mesh onto a substrate. The flow behavior of thick film ink depends on its viscosity and surface tension. Screen printing utilizes the shear thinning properties of inks, where viscosity decreases under the high shear stress of printing. Key variables in screen printing include screen mesh properties, machine settings, ink rheology, and squeegee materials and hardness. Screen printing is commonly used in the electronics industry to apply conductive pastes for applications like hybrid ICs, resistors, and electrodes for devices like electroluminescent lamps.
1. Trends in the automotive industry like weight reduction and lower environmental impact are driving changes in pretreatment and electrocoat technologies.
2. Green pretreatments without phosphates are growing but have limitations in corrosion performance; electrocoats need to compensate for the differences in substrate properties.
3. Compact topcoat processes require a robust electrocoat process to avoid sanding and achieve a good appearance; experience has shown several OEMs successfully using PPG electrocoat in these processes.
4. New electrocoat concepts like hyperthrow aim to reduce coating usage and improve throw power, especially for difficult areas, to allow for higher production throughput.
This document discusses a lecture on advanced electronic materials processing. Specifically, it covers ceramic processing techniques for fabricating multilayer ceramic capacitors (MLCCs). Key topics include preparing high-purity ceramic powders, optimizing powder characteristics like size and dispersion for tape casting, and production processes like tape casting, printing, and lamination. The goal is to enable mass production of smaller 0402 size MLCCs using finer ceramic powders and more advanced processing methods.
Deformulating Complex Polymer Mixtures By GPC-IR Technologymzhou45
This document summarizes a presentation on using hyphenated GPC-IR technology to de-formulate complex polymer mixtures. The presentation discusses the DiscovIR-LC system and its features for GPC-IR and HPLC-IR analysis. It provides several case studies demonstrating how GPC-IR can be used to identify individual polymer components, characterize copolymer compositions, analyze polymer additives and degradation, and more. The speaker concludes that GPC-IR is a powerful tool for de-formulating complex polymer systems and problem solving in various industries.
This document summarizes the synthesis, characterization, and properties of nickel ferrite (NiFe3O4) nanoparticles. Nickel ferrite was synthesized using a sol-gel technique and sintered at 600°C. X-ray diffraction analysis confirmed the formation of nickel ferrite and showed structural changes due to ion shifting between lattice sites. Scanning electron microscopy images showed agglomerated, porous nanoparticles with an average size of 0.21μm. AC conductivity measurements showed a conductivity of 1.0 x 10-4 S/cm due to dipole polarization. Dielectric properties were also measured as a function of frequency.
Electrochemical Synthesis of MoO3 Nanoparticles Effect of Temperature Convert...IJERA Editor
MoO3 nanorods were prepared by electrochemical reduction method using the tetra propyl ammonium bromide (TPAB) was structure directing agent in an organic medium viz. tetra hydro furan (THF) and acetonitrile (ACN) in 4:1 ratio and at current density 14mA &18 mA. The reduction process takes place under atmospheric condition over a period of 2 h. Dried sample was calcinated in muffle furnace at 500ºC. The parameters such as current density and concentration of stabilizers were used to control the size of nanorods. The synthesized MoO3 nanorods were characterized by using UV-Visible, FT-IR, XRD, SEM-EDS and TEM analysis techniques.
This document summarizes a numerical simulation of a rotary kiln. The simulation models turbulent combustion, heat transfer, and granular flow inside the kiln. It seeks to understand formation of rings within the kiln and optimize production. The model considers chemical reactions, turbulence, radiation heat transfer, and NOx formation. It was used to test adjusting the fuel-air ratio to reduce temperature peaks that cause rings. Increasing the ratio from 10 to 12 successfully destroyed an existing ring over 24 hours by lowering the liquid phase temperature below self-sustaining levels. The model will further explore configurations to prevent or counteract ring formation and reduce NOx emissions.
This document summarizes research on producing activated carbon from waste tea using potassium carbonate (K2CO3) as the activating agent. The objectives were to use waste tea as a raw material and determine how process parameters influence the activated carbon characteristics. Waste tea was carbonized at different temperatures and times, with varying K2CO3 amounts and impregnation periods. Testing showed that the surface area, yield, micropore and mesopore volumes depended on the carbonization conditions and K2CO3 levels. Micropores predominantly formed between 500-800°C, while mesopores increased at 900°C. Waste tea proved a potential low-cost source for high surface area, porous activated carbon.
1) IMEC fabricated Cu2ZnSnSe4 solar cells with up to 6.3% efficiency by selenizing sputtered metal precursor layers.
2) Characterization found strong evaporation of Zn and Sn during selenization, doping levels around 1016 cm-3, and recombination centers limiting VOC to around 400 mV.
3) The best cell showed a JSC of 36.1 mA/cm2 but series resistance increased significantly at low temperature due to poor adhesion. Doping and defect densities correlated exponentially with Zn/Sn ratio in the absorber.
The nanochemistry group at ISOF works on the production of graphene by chemical exfoliation, its chemical functionalization through covalent or supramolecular interactions, and its characterization at the nanometric scale. They produce graphene oxide which can be produced in large scale and is highly soluble in water and some organic solvents. The group also works on controlling the size of graphene oxide sheets from 1 um to 100 um and depositing them uniformly on substrates over large areas.
This document outlines a study on producing nitrogen enriched carbon coated graphene scaffolds for use in supercapacitors. Graphene oxide was synthesized using a modified Hummer's method and then reduced to produce reduced graphene oxide. Some samples were further modified by enriching with nitrogen and coating with carbon from glucose. Characterization with SEM, UV spectroscopy and cyclic voltammetry showed the nitrogen enriched carbon coated reduced graphene oxide had higher porosity, lower oxygen content and higher specific capacitance, making it a promising electrode material for capacitive energy storage.
The document summarizes research on reinforcing metals and polymers with graphene. Graphene has desirable properties including high strength and conductivity. The researchers produced aluminum-graphene and PDMS-graphene composites using powder metallurgy and solvent mixing. Tensile tests showed the composites had higher strength and flexibility than the base materials alone. Further work is needed to fully characterize the composites and explore applications like microfluidics.
The document summarizes two methods for synthesizing nanostructured ceramic powders: the mimic alkoxide method and hydrothermal synthesis.
The mimic alkoxide method involves dissolving a cerium precursor in alcohol and adding it dropwise to a precipitating solution, producing nanocrystalline powder with primary particles around 15nm that are well-sintered at lower temperatures than aqueous precipitation.
Hydrothermal synthesis uses high-temperature high-pressure water to precipitate oxides from precursor solutions, producing crystalline anhydrous powder without needing calcination or milling, and employing inexpensive raw materials. It is highlighted for making solid-solution particles for multilayer ceramic capacitors.
This document reports on a study of the photophysical and electroluminescent properties of a conjugated-nonconjugated multi-block copolymer. Time-resolved fluorescence experiments and comparisons of solution and solid state fluorescence indicate that in the solid state, emission comes from associated species like ground state dimers or excimers, rather than isolated chromophores. Absorption, fluorescence, FTIR and NMR spectroscopy were used to characterize the materials. Light-emitting diodes were fabricated using the copolymer to study its electroluminescent properties.
The document discusses several methods for determining the size of fine powder particles, including:
1. Calculating mean diameter based on measurements of individual particle sizes and accounting for polydispersity.
2. Using scanning electron microscopy and transmission electron microscopy to directly measure particle sizes.
3. Employing sedimentation techniques like photo-sedimentation and X-ray sedimentation, based on Stokes' equations, to determine particle size distributions.
4. Analyzing particle shapes using flow-based systems that inject a thin, monolayered stream of particles into a flow cell for microscopic imaging and size calculations.
The document summarizes key aspects of low-temperature co-fired ceramic (LTCC) technology for applications in radio frequency (RF) modules. It discusses how LTCC enables miniaturization through multi-layer integration at lower costs than other technologies like thin film. Specific advantages highlighted include high density packaging, parallel processing for shorter development times, design flexibility through buried passive components, and compatibility with various conductors and materials for resistors and capacitors suitable for co-firing. Process details covered include via formation, conductor printing, lamination, and sintering around 850°C to enable silver electrodes. Example applications and performance metrics are also summarized.
Anomalous Behavior Of SSPC In Highly Crystallized Undoped Microcrystalline Si...Sanjay Ram
Microcrystalline silicon is a heterogenous material. We show that different effective DOS distribution can be possible for micro-structurally different μc--Si:H thin films
This document summarizes a study on the effect of atomic layer deposited (ALD) Al2O3 barrier layers of varying thicknesses on forward electron injection from Ru(dcbpy)2(NCS)2 dye to nanocrystalline TiO2 films. Transient absorption spectroscopy showed that a single ALD cycle producing a 1 Å Al2O3 layer decreased singlet electron injection, while more than two cycles also slowed triplet injection. The findings indicate that Al2O3 barriers suppress total electron injection by weakening electronic coupling between the dye and TiO2 and modifying the TiO2 electronic structure. ALD allows precise control of barrier thickness and uniform coverage, making it superior to sol-gel methods for this application.
This document summarizes research on synthesizing and analyzing yttrium-doped barium cerate (BCY) thin films for use as a proton-conducting electrolyte in solid oxide fuel cells. Key points discussed include:
1. BCY films were deposited via spray pyrolysis onto alumina substrates and analyzed using thermo gravimetric analysis, XRD, and SEM to study crystallinity and morphology.
2. XRD and conductivity results showed the films achieved phase-pure and dense structures when annealed at 900°C, with maximum conductivity of 2.45 × 10−3 S cm−1 at 600°C in argon atmosphere.
3. The results indicate spray pyro
Screen printing is a process that involves transferring ink through a mesh onto a substrate. The flow behavior of thick film ink depends on its viscosity and surface tension. Screen printing utilizes the shear thinning properties of inks, where viscosity decreases under the high shear stress of printing. Key variables in screen printing include screen mesh properties, machine settings, ink rheology, and squeegee materials and hardness. Screen printing is commonly used in the electronics industry to apply conductive pastes for applications like hybrid ICs, resistors, and electrodes for devices like electroluminescent lamps.
1. Trends in the automotive industry like weight reduction and lower environmental impact are driving changes in pretreatment and electrocoat technologies.
2. Green pretreatments without phosphates are growing but have limitations in corrosion performance; electrocoats need to compensate for the differences in substrate properties.
3. Compact topcoat processes require a robust electrocoat process to avoid sanding and achieve a good appearance; experience has shown several OEMs successfully using PPG electrocoat in these processes.
4. New electrocoat concepts like hyperthrow aim to reduce coating usage and improve throw power, especially for difficult areas, to allow for higher production throughput.
This document discusses a lecture on advanced electronic materials processing. Specifically, it covers ceramic processing techniques for fabricating multilayer ceramic capacitors (MLCCs). Key topics include preparing high-purity ceramic powders, optimizing powder characteristics like size and dispersion for tape casting, and production processes like tape casting, printing, and lamination. The goal is to enable mass production of smaller 0402 size MLCCs using finer ceramic powders and more advanced processing methods.
Deformulating Complex Polymer Mixtures By GPC-IR Technologymzhou45
This document summarizes a presentation on using hyphenated GPC-IR technology to de-formulate complex polymer mixtures. The presentation discusses the DiscovIR-LC system and its features for GPC-IR and HPLC-IR analysis. It provides several case studies demonstrating how GPC-IR can be used to identify individual polymer components, characterize copolymer compositions, analyze polymer additives and degradation, and more. The speaker concludes that GPC-IR is a powerful tool for de-formulating complex polymer systems and problem solving in various industries.
This document summarizes the synthesis, characterization, and properties of nickel ferrite (NiFe3O4) nanoparticles. Nickel ferrite was synthesized using a sol-gel technique and sintered at 600°C. X-ray diffraction analysis confirmed the formation of nickel ferrite and showed structural changes due to ion shifting between lattice sites. Scanning electron microscopy images showed agglomerated, porous nanoparticles with an average size of 0.21μm. AC conductivity measurements showed a conductivity of 1.0 x 10-4 S/cm due to dipole polarization. Dielectric properties were also measured as a function of frequency.
Electrochemical Synthesis of MoO3 Nanoparticles Effect of Temperature Convert...IJERA Editor
MoO3 nanorods were prepared by electrochemical reduction method using the tetra propyl ammonium bromide (TPAB) was structure directing agent in an organic medium viz. tetra hydro furan (THF) and acetonitrile (ACN) in 4:1 ratio and at current density 14mA &18 mA. The reduction process takes place under atmospheric condition over a period of 2 h. Dried sample was calcinated in muffle furnace at 500ºC. The parameters such as current density and concentration of stabilizers were used to control the size of nanorods. The synthesized MoO3 nanorods were characterized by using UV-Visible, FT-IR, XRD, SEM-EDS and TEM analysis techniques.
This document summarizes a numerical simulation of a rotary kiln. The simulation models turbulent combustion, heat transfer, and granular flow inside the kiln. It seeks to understand formation of rings within the kiln and optimize production. The model considers chemical reactions, turbulence, radiation heat transfer, and NOx formation. It was used to test adjusting the fuel-air ratio to reduce temperature peaks that cause rings. Increasing the ratio from 10 to 12 successfully destroyed an existing ring over 24 hours by lowering the liquid phase temperature below self-sustaining levels. The model will further explore configurations to prevent or counteract ring formation and reduce NOx emissions.
This document summarizes research on producing activated carbon from waste tea using potassium carbonate (K2CO3) as the activating agent. The objectives were to use waste tea as a raw material and determine how process parameters influence the activated carbon characteristics. Waste tea was carbonized at different temperatures and times, with varying K2CO3 amounts and impregnation periods. Testing showed that the surface area, yield, micropore and mesopore volumes depended on the carbonization conditions and K2CO3 levels. Micropores predominantly formed between 500-800°C, while mesopores increased at 900°C. Waste tea proved a potential low-cost source for high surface area, porous activated carbon.
1) IMEC fabricated Cu2ZnSnSe4 solar cells with up to 6.3% efficiency by selenizing sputtered metal precursor layers.
2) Characterization found strong evaporation of Zn and Sn during selenization, doping levels around 1016 cm-3, and recombination centers limiting VOC to around 400 mV.
3) The best cell showed a JSC of 36.1 mA/cm2 but series resistance increased significantly at low temperature due to poor adhesion. Doping and defect densities correlated exponentially with Zn/Sn ratio in the absorber.
The nanochemistry group at ISOF works on the production of graphene by chemical exfoliation, its chemical functionalization through covalent or supramolecular interactions, and its characterization at the nanometric scale. They produce graphene oxide which can be produced in large scale and is highly soluble in water and some organic solvents. The group also works on controlling the size of graphene oxide sheets from 1 um to 100 um and depositing them uniformly on substrates over large areas.
The document summarizes research on inkjet-printed graphene for flexible micro-supercapacitors. Graphene is an ideal electrode material due to its high surface area, conductivity, and stability. The researchers used graphene oxide ink that was reduced to graphene after printing. Printed graphene films were highly porous with a surface area of 282 m2/g. Electrochemical testing showed the printed graphene achieved a capacitance of 132 F/g and could be charged and discharged rapidly while retaining 97% of its capacitance over many cycles. The research demonstrated inkjet printing as a scalable method for producing graphene-based flexible micro-supercapacitors.
This document summarizes a conference presentation on conducting polymer nanofibers and graphene. It discusses how polyacetylene nanofibers have intrinsic conductivity similar to metals. It also summarizes the 2010 Nobel Prize in Physics that was awarded for the discovery of graphene, a single layer of carbon atoms with unusual electronic properties. The document concludes by describing several methods for producing graphene sheets, including mechanical exfoliation of graphite and chemical vapor deposition.
Graphene is a two-dimensional material composed of carbon atoms arranged in a hexagonal lattice. It has unique electrical, mechanical, and optical properties. In 2004, Geim and Novoselov developed the "scotch tape" method to isolate single-atom thick graphene sheets from graphite. This discovery led to the 2010 Nobel Prize in Physics. Graphene is synthesized through exfoliation of graphite or epitaxial growth on metal substrates. Potential future applications of graphene include use in biological engineering, optical electronics like touchscreens, ultrafiltration, photovoltaics, composite materials, and supercapacitors.
The document summarizes a study on the effect of In, Ce, and Bi dopings on sintering and dielectric properties of Ba(Zn1/3Nb2/3)O3 (BZN) ceramics. In doping between 0.2-4.0% increased density at 1300°C. Ce doping decreased density at 1250°C. Bi doping up to 1.0% negatively affected densification, while higher levels improved it. XRD showed single phase formation for all dopant levels except 0.5% Bi. In and Ce doping increased dielectric constant from 41 to around 66 at 1 MHz. Bi doping initially decreased then increased dielectric constant with higher levels.
The document discusses the Air Force Office of Scientific Research (AFOSR) portfolio on aerospace materials for extreme environments. The portfolio aims to provide fundamental knowledge to enable advances in future Air Force technologies through discovering and characterizing materials that can withstand extreme environments involving mechanical, thermal, and electromagnetic loads. It covers theoretical and computational tools to aid materials discovery, physics and chemistry of materials in stressed environments, and experimental tools to address complexity from combined external fields in extreme conditions.
Application Note: Study Rigid Amorphous Fraction in Polymer Nano-Composites b...PerkinElmer, Inc.
It is known that there is a rigid amorphous fraction (RAF) in semicrystalline polymers. The RAF exists at the interface of crystal and amorphous phase as a result of the immobilization of a polymer chain due to the crystal.
Here, heat capacity measurment has been performed in order to detect a possible second Tg on nanocomposites of polymethyl methacrulate (PMMA) with silicon oxide nanoparticles of dfferent shape. StepScan(TM) DSC was used for determination of precise heat capacity and HyperDSC(R) to prevent degradation and identify devitrification of the RAF at elevated temperatures.
The document discusses sediment classification using sub-bottom profiler data. It outlines high and low frequency classification methods. For high frequency data, a model-based approach is used involving matching observed echo envelopes to modeled envelopes to determine sediment type. For low frequency data, an energy model is used to relate reflected energy to sediment properties. The document concludes the energy model could be improved by accounting for additional physical phenomena and recommends calibration to increase classification certainty.
Tantawi - Measurements of RF properties of Novel Superconducting Materialsthinfilmsworkshop
http://www.surfacetreatments.it/thinfilms
Measurements of RF properties of Novel Superconducting Materials (Sami Tantawi - 20')
Speaker: Sami Tantawi - SLAC National Accelerator Laboratory | Duration: 20 min.
Abstract
We have developed an X-band SRF testing system using a high-Q copper cavity with an interchangeable flat bottom for the testing of different materials. By measuring the Q of the cavity, the system is capable to characterize the quenching magnetic field of the superconducting samples at different power level and temperature, as well as the surface resistivity. This paper will present the most recent development of the system and testing results.
BBO is very good for tunable laser sources, such as ultrafast Ti:Sapphire or dye lasers. And it is also widely used for SHG, 3HG, 4HG, and autocorrelation of femtosecond and picosecond Ti:Sapphire lasers; SHG, 3HG, 4HG, 5HG of YAG lasers at 1064 nm and 1320 nm to yield output of 212-660nm; SHG of tunable dye or solid-state laser sources from 410-750 nm to yield output of 205-375 nm, SFM of dye laser and YAG harmonics to yield output of 189-400 nm; DFM (difference-frequency mixing) from the Visible to the IR range up to over 3000 nm; OPO pumped with SHG or 3HG of YAG or Ti:Sapphire with an output range of 400-3000 ; Intracavity SHG of Argon ion lasers (488, 514 nm) or Copper vapor lasers (510 nm, 578 nm).
This document summarizes research characterizing nano-Ag/PVP composites synthesized via ultra-violet irradiation. Nano-silver/polyvinylpyrrolidone composites were prepared by reducing silver nitrate and polymerizing N-vinyl pyrrolidone simultaneously under UV light, without additional reagents. Characterization using FT-IR, XRD, TEM and XPS showed that spherical silver nanoparticles around 5 nm were homogenously dispersed in the PVP polymer matrix. Spectroscopy indicated interactions between nano silver and carbonyl oxygen as well as nitrogen groups in PVP through pi-conjugation effects.
Application of carbon nanotubes in water desalinationAnkit Kumar Singh
This document discusses several applications of carbon nanotubes (CNTs) in water desalination. It describes how CNT sheets, membranes, and vertically-aligned CNTs can be used to remove salt from water. CNT sheets are synthesized and characterized, showing their ability to adsorb salt. CNT membranes are prepared using different encapsulation methods and shown to have nanopores that can selectively filter ions. Vertically-aligned CNT membranes are grown via CVD and densified to form porous structures for desalination. Multi-walled CNT electrodes are also tested in a desalination device, demonstrating salt removal from water.
This document discusses scintillator materials for gamma ray spectroscopy. It describes Lawrence Livermore National Laboratory's efforts to develop new scintillator materials with high energy resolution and stopping power to discriminate gamma ray spectra, while being low cost and having no intrinsic radioactivity. Some promising new materials discussed include single crystal strontium iodide doped with europium, ceramic gadolinium gallium aluminum garnet doped with cerium, and bismuth-loaded polymer plastics. These new materials show energy resolutions that improve on existing sodium iodide and offer potential for lower cost gamma spectroscopy detectors.
Graphene: the world's first 2D material. Since graphene's isolation in 2004, it has captured the attention of scientists, researchers, and industry worldwide.
PerkinElmer: Nano-Composites Characterization by Differential Scanning Calori...PerkinElmer, Inc.
This document summarizes a study that used an improved HyperDSC method to measure the specific heat capacity of nanocomposites up to high temperatures without degradation. The method involves rapidly heating and cooling samples at 400°C/min to obtain Cp data without dwelling at high temperatures. Testing on sapphire standards showed the new method achieves accuracy within 1-1.5% compared to literature values. The method was used to analyze thermoplastic polyurethane and epoxy nanocomposites, with the epoxy data possibly showing evidence of devitrification through multiple glass transition temperatures. The improved HyperDSC method extends the temperature range for accurate Cp measurements and could help identify devitrification in
This document discusses the synthesis of nano materials using sputtering. It first provides background on nanomaterials and describes electron beam lithography and sputtering processes. The document then details an experiment where alumina and silica nano materials were synthesized. Electron beam lithography was used to create a pattern on a resist-coated wafer, which was then subjected to sputtering deposition of alumina and silica. Scanning electron microscopy and atomic force microscopy characterization revealed uniformly distributed 50nm cubes with good adhesive properties and low surface roughness.
This document discusses the synthesis of nano materials using sputtering. It first provides background on nanomaterials and describes electron beam lithography and sputtering processes. The document then details an experiment where alumina and silica nano materials were synthesized. Electron beam lithography was used to create a pattern on a resist-coated wafer, which was then subjected to sputtering deposition of alumina and silica. Scanning electron microscopy and atomic force microscopy characterization revealed uniformly distributed 50nm cubes with good adhesive properties and low surface roughness.
This document discusses the synthesis of nano materials using sputtering. It begins by introducing nano materials and describing electron beam lithography and sputtering processes. The document then details the experimental procedure used, which involves using EBL to pattern PMMA resist on a silicon nitride wafer with a desired pattern. Sputtering is then used to co-deposit alumina and silica onto the patterned wafer. Scanning electron microscopy and atomic force microscopy are used to characterize the synthesized nano materials and confirm the presence of uniformly distributed 50nm cubes. Analysis of SEM and AFM images shows the nano materials have a flat surface, good adhesiveness, and low surface roughness.
Similar to Nafen Generic Technical Presentation (20)
2. Nafen™ is a new material on the market:
alumina nanofibers in gamma / chi phase
Parameter value
Phase gamma / chi
Mean fiber diameter, nm 7-10 / 30-40
Fiber length, mm 1–150
Specific surface area (BET), m2/g 155
Purity, % 99.7
Specific gravity, g/cm3 3.98
Bulk density, g/cm3 0.1 to 0.4
Nafen is unique because of its industrial-scale production technology.
It is synthesized from liquid aluminum melt which ensures continuous
production rate over 0.5 kg/hour even at pilot stage.
1
4. TEM micrographs / National University of Science and
Technology MISiS (Moscow, Russia)
TEM images demonstrate fine fiber diameter and length-to-diameter ratio
3
5. Two types of Nafen fibers are currently produced:
with average diameters of 7-10 and 30-40 nm
TEM and fiber diameter distribution for the two types of fibers
8 nm average diameter 35 nm average diameter
4
6. Nafen is produced in blocks of co-aligned fibers
Fibers are co-aligned and arranged in bundles
- distance between fibers in block is 20 to 40 nm
- block size is up to 50x50 cm
- block height is up to 15 cm (along the fibers)
- bulk density is 0.1 to 0.4 g/cm3
- block thermal conductivity is 0.025 W/m•K,
close to that of air
- fibers are easily separated by wetting in water
or alcohols
W-20
SEM
5
8. Elemental analysis (EDX) at various
temperatures and TGA / UCambridge (UK)
Elemental Analysis
Elemental Analysis
37:63
44:5637:63 46:54 46:54 45:55
46:54 46:54 45:55
Saffil
GreyNafen 7 nm
to white
Nafen 12 nm
Grey to white
T, C 20 1000 1270 1400
Al to O weight ratio is close to Al2O3 The material loses up to 10% weight when heated
- Al2O3 corresponds to 48:54 - due to water desorption
- deviation at low temperature is due to - Saffil is shown as a reference alumina material
water adsorption
- small deviation at high temperature is
due to vacant Al bonds on the surface
7
9. Phase analysis (XRD) / IC SB RAS (Novosibirsk,
Russia)
Typical diffraction patterns for low-
temperature phases of alumina
- gamma and etha are cubic spinels
- chi is also cubic, but with additional
hexagonal packing (check term)
- chi is identified by the peak at 42.8
Diffraction patterns
of two samples of Nafen
- the phase is identified as mostly chi
for these particular samples, with
some gamma
- different samples have varying
gamma/chi ratio, depending on the
synthesis process parameters
- crystallite size 50-100 nm
Nafen fibers are
polycrystalline alumina in
gamma and chi phases
8
10. High-temperature phase transformation (XRD) /
PANanalytical
emperature XRD
At 1200–1400 C, transformation
to alpha phase occurs
Series of XRD spectra during samples heating 10
9
12. нию d=4/ρA. Для значения плотности 3.89
г/см BET specific surface area / БЭТ 155 м2/г, а d=6.6 нм.
3
и удельной поверхности по IC SB RAS
, а d=6.6 нм.
(Novosibirsk, Russia)
Nitrogen adsorption-desorption method (BET)
adsorption
cm3/g
desorption
ции азота образца 29/11 при 77К.
P/P0
7
Specific surface area is measured at 155 cm2/g
- this corresponds to the geometric surface
Рис. 2.2. Изотермы адсорбции-десорбции азота образца
- hence, no micropores or surface defects 29/11 при 77К.
11
13. (Рис.3.4Б), т.е. есть и зубцы, и плоские участки поверхности. Угол 120о характерен для
The surface is ‘saw-shaped’, faceted at various
плоскостей плотнейшей упаковки атомов кислорода (111). Напомним, что для
angles (TEM) / IC SB RAN (Novosibirsk, Russia)
традиционного c-Al O , полученного прокаливанием гиббсита, характерна
2 3
пластинчатая форма кристаллитов с развитой гранью 111.
ционные картины образцов 29/11 и 22.
гласно микроскопии высокого разрешения волокна
убцов равен 120о) (Рис.3.4А), либо перекручены
ие участки поверхности. Угол 120о характерен для
атомов кислорода (111). Напомним, что для
нного прокаливанием гиббсита, характерна
развитой гранью 111. А Б
Рис.3.4А. Волокно, зубчатые края, угол 120о (вид сверху на плоскость (111)).
Рис.3.4Б. Перекрученное волокно. Одна часть с зубчатыми краями (вид сверху на
плоскость (111), вторая с ровными краями (вид сбоку на упаковку полоскостей (111))[111]
11
А Б
ол 120о (вид сверху на плоскость (111)).
дна часть с зубчатыми краями (вид сверху на Рис. 5.8. Ориентация фасеток увеличенного размера (5 нм и более). 12
18. XRD Position 3 / Bruker
Peaks are sharper and it seems that there is some preferred
orientation (intensity ratio does not fit anymore to the expected one).
17
20. наблюдаются максимумы /г,при 20 нм (по десорбции) и 40 нм (по адсорбц
и удельной поверхности по БЭТ 155 м а d=6.6 нм.
Pore size distribution / IC SB RAS (Novosibirsk,
видимому, соответствующие порам между волокнами.
Russia)
dV/dD cm3/g nm
adsorption
desorption
Рис. 2.2. Изотермы адсорбции-десорбции азота образца 29/11 при 77К.
Pore diameter D, nm
7
Рис. 2.3. Распределение объѐма пор по размерам.
Maximum pore size (20 nm) corresponds to the inter-fiber distance
- hence, no micropores
19