This document discusses using the piezoelectric effect to generate X-rays. A piezoelectric crystal is driven at its resonant frequency to achieve high voltage output. Electrons are emitted from a field emission diode on the crystal and are accelerated by the high voltage to strike a metal target, producing X-rays via bremsstrahlung interactions. Experimental results showed X-rays produced with energies up to 130 keV using a lithium niobate crystal driven at 30-31 kHz. Spectra under various conditions demonstrated X-ray generation using this piezoelectric method.
IRJET- Dielectric Properties of Titanium Substituted Manganese -Zinc Ferr...IRJET Journal
1. The document describes a study on the dielectric properties of a new crystalline ceramic material called Titanium Substituted Manganese -Zinc Ferrite System Mn0.8+xZn0.2TixFe2-2xO4 with x=0.20.
2. The dielectric properties measured include dielectric constant, dielectric loss, conductivity, and impedance and how they vary with frequency and temperature.
3. The material was prepared using a solid state reaction method and its dielectric properties were analyzed and discussed in terms of applications in electronics.
Extensive efforts have been made to harvest energy f from water in the form of raindrops, river and ocean wave, tidal and others. However, achieving a high-density of electrical power generation is challenging. Traditional hydraulic power generation mainly uses electromagnetic generators that are heavy, bulky, and become inefficient with water supply. Alternative, the water droplet or solid-based electric nano-generator, has so far generated peak power densities for less than one watt per square meter, owing to the limit at ions imposed by interfacial effects as seen in characterization of the charge generation and transfer that occur at solid-liquid or liquid-solid interfaces. Here we develop a device to harvest energy from impinging water droplet s by using an architecture that compromises a polytetrafluoroethylene film on an indium oxide substrate plus an aluminium electrode. We show that spreading of an impinged water droplet on the device bridges, the originally disconnect ed component s into a closed-loop electrical system, transforming the conventional interfacial effect into bulk effect, and so enhancing device that is limited by interfacial effects.
Electrical treeing and partial discharge characteristics of silicone rubber f...IJECEIAES
This article presents a study on electrical treeing performances with its associated partial discharge (PD) and the influence of filler concentration in silicone rubber (SiR) samples which are filled with silicon dioxide (SiO2) and silicon nitride (Si3N4) as nanofillers for electrical tree growth suppression. There are many researches on electrical treeing in SiR with SiO2 nanofillers but none of the publication have reported on Si3N4 nanofillers for suppression of the electrical tree growth. In this study, the treeing experiments were conducted by applying a fixed AC voltage of 10 kV and 12 kV at power frequency of 50 Hz on unfilled SiR, SiR/SiO2, and SiR/Si3N4 nanocomposites with different filler concentrations by 1, 3, and 5 weight percentage (wt%) and the treeing parameters were observed with its correlated PD patterns. The outcome from this study found that the SiR/Si3N4 nanocomposites were able to withstand the electrical treeing better than the pure SiR or SiR/SiO2 nanocomposites. Furthermore, the increase in filler concentration improved the electrical tree performances of the nanocomposites. This finding suggests the Si3N4 can be used as filler in polymeric insulating materials for electrical tree inhibition. Meanwhile, the PD activity shows increment when the tree progresses thereby indicating correlation in both parameters which can be as key parameter for monitoring unseen treeing in non-transparent samples.
Dr. M. Jayalakshmi is an electrochemist with over 20 years of experience in materials synthesis and characterization. She has worked on projects related to electrode materials for batteries and supercapacitors. Her background includes electroplating, electroless plating, and synthesis of transition metal oxides, sulfides, and lithium metal oxides. She is currently a Principal Scientist at NFTDC in India, where she leads several projects on electrodeposition, battery technologies, and solar cell materials.
2022 recent advances on quasi-solid-state electrolytes for supercapacitorsAry Assuncao
This document reviews recent advances in quasi-solid-state electrolytes for supercapacitors. Quasi-solid-state electrolytes provide advantages over liquid electrolytes such as reduced leakage and safety concerns while maintaining high ionic conductivity. The document summarizes different types of quasi-solid-state electrolytes including gel-polymer electrolytes and discusses their properties. It also performs a bibliographic analysis of over 300 references on parameters like ionic conductivity, capacitance, stability, and working voltage window of various quasi-solid-state electrolytes. The document concludes that gel-polymer electrolytes and aqueous-based electrolytes show promise for flexible supercapacitors but that further development is needed to improve performance.
Optimization of electric energy density in epoxy aluminiumiaemedu
This document discusses optimizing the electric energy density of epoxy-aluminum nanocomposites for use as dielectric materials. It presents a three-phase model to characterize the nanocomposite's dielectric properties as a function of aluminum particle size and volume fraction. Numerical results show that permittivity increases drastically near the percolation threshold. While breakdown strength decreases with higher volume fractions, the overall energy density is significantly higher than pure epoxy. Maximum energy density occurs at an optimal particle size and concentration balancing high permittivity and maintaining breakdown strength. Careful control of microstructure is important to avoid defects and achieve expected energy density gains.
IRJET- Dielectric Properties of Titanium Substituted Manganese -Zinc Ferr...IRJET Journal
1. The document describes a study on the dielectric properties of a new crystalline ceramic material called Titanium Substituted Manganese -Zinc Ferrite System Mn0.8+xZn0.2TixFe2-2xO4 with x=0.20.
2. The dielectric properties measured include dielectric constant, dielectric loss, conductivity, and impedance and how they vary with frequency and temperature.
3. The material was prepared using a solid state reaction method and its dielectric properties were analyzed and discussed in terms of applications in electronics.
Extensive efforts have been made to harvest energy f from water in the form of raindrops, river and ocean wave, tidal and others. However, achieving a high-density of electrical power generation is challenging. Traditional hydraulic power generation mainly uses electromagnetic generators that are heavy, bulky, and become inefficient with water supply. Alternative, the water droplet or solid-based electric nano-generator, has so far generated peak power densities for less than one watt per square meter, owing to the limit at ions imposed by interfacial effects as seen in characterization of the charge generation and transfer that occur at solid-liquid or liquid-solid interfaces. Here we develop a device to harvest energy from impinging water droplet s by using an architecture that compromises a polytetrafluoroethylene film on an indium oxide substrate plus an aluminium electrode. We show that spreading of an impinged water droplet on the device bridges, the originally disconnect ed component s into a closed-loop electrical system, transforming the conventional interfacial effect into bulk effect, and so enhancing device that is limited by interfacial effects.
Electrical treeing and partial discharge characteristics of silicone rubber f...IJECEIAES
This article presents a study on electrical treeing performances with its associated partial discharge (PD) and the influence of filler concentration in silicone rubber (SiR) samples which are filled with silicon dioxide (SiO2) and silicon nitride (Si3N4) as nanofillers for electrical tree growth suppression. There are many researches on electrical treeing in SiR with SiO2 nanofillers but none of the publication have reported on Si3N4 nanofillers for suppression of the electrical tree growth. In this study, the treeing experiments were conducted by applying a fixed AC voltage of 10 kV and 12 kV at power frequency of 50 Hz on unfilled SiR, SiR/SiO2, and SiR/Si3N4 nanocomposites with different filler concentrations by 1, 3, and 5 weight percentage (wt%) and the treeing parameters were observed with its correlated PD patterns. The outcome from this study found that the SiR/Si3N4 nanocomposites were able to withstand the electrical treeing better than the pure SiR or SiR/SiO2 nanocomposites. Furthermore, the increase in filler concentration improved the electrical tree performances of the nanocomposites. This finding suggests the Si3N4 can be used as filler in polymeric insulating materials for electrical tree inhibition. Meanwhile, the PD activity shows increment when the tree progresses thereby indicating correlation in both parameters which can be as key parameter for monitoring unseen treeing in non-transparent samples.
Dr. M. Jayalakshmi is an electrochemist with over 20 years of experience in materials synthesis and characterization. She has worked on projects related to electrode materials for batteries and supercapacitors. Her background includes electroplating, electroless plating, and synthesis of transition metal oxides, sulfides, and lithium metal oxides. She is currently a Principal Scientist at NFTDC in India, where she leads several projects on electrodeposition, battery technologies, and solar cell materials.
2022 recent advances on quasi-solid-state electrolytes for supercapacitorsAry Assuncao
This document reviews recent advances in quasi-solid-state electrolytes for supercapacitors. Quasi-solid-state electrolytes provide advantages over liquid electrolytes such as reduced leakage and safety concerns while maintaining high ionic conductivity. The document summarizes different types of quasi-solid-state electrolytes including gel-polymer electrolytes and discusses their properties. It also performs a bibliographic analysis of over 300 references on parameters like ionic conductivity, capacitance, stability, and working voltage window of various quasi-solid-state electrolytes. The document concludes that gel-polymer electrolytes and aqueous-based electrolytes show promise for flexible supercapacitors but that further development is needed to improve performance.
Optimization of electric energy density in epoxy aluminiumiaemedu
This document discusses optimizing the electric energy density of epoxy-aluminum nanocomposites for use as dielectric materials. It presents a three-phase model to characterize the nanocomposite's dielectric properties as a function of aluminum particle size and volume fraction. Numerical results show that permittivity increases drastically near the percolation threshold. While breakdown strength decreases with higher volume fractions, the overall energy density is significantly higher than pure epoxy. Maximum energy density occurs at an optimal particle size and concentration balancing high permittivity and maintaining breakdown strength. Careful control of microstructure is important to avoid defects and achieve expected energy density gains.
Optimization of electric energy density in epoxy aluminium nanocompositeiaemedu
This document summarizes research on optimizing the electric energy density of epoxy-aluminum nanocomposites. It models the nanocomposite as a three-phase material and evaluates how aluminum particle size and filler loading affect permittivity, breakdown strength, and energy density. Numerical results show permittivity increases drastically near the percolation threshold. As filler volume increases, breakdown strength decreases but energy density notably increases. The optimal filler size and concentration for maximum energy density are evaluated, with inter-particle distance controlling breakdown strength significantly impacting energy storage capacity.
Vineet Jagadeesan Nair designed and tested dye-sensitized solar cells using novel organic dye sensitizers to improve power conversion efficiency and long-term stability. Through co-sensitization techniques and material optimizations, a champion efficiency of over 9% was achieved. Organic dyes offer advantages over traditional ruthenium-based dyes such as lower cost and easier synthesis, but have disadvantages including weaker light absorption and shorter exciton lifetimes. Co-sensitization of dyes with complementary absorption spectra can improve overall light harvesting.
1. The document describes a new nanohybrid material composed of polyoxomolybdate, polypyrrole, and graphene oxide for use as a high-power symmetric supercapacitor electrode.
2. The nanohybrid was synthesized via a one-pot reaction where polyoxomolybdate acted as an oxidizing agent to polymerize pyrrole monomers onto graphene oxide nanosheets.
3. Structural and morphological analysis showed the nanohybrid had an excellent architecture with good interfacial contact between components, enabling fast redox reactions for high capacitive performance.
Performance comparison of selection nanoparticles for insulation of three cor...IJECEIAES
This paper presents an investigation on the enhancement of electrical insulations of power cables materials using a new multi-nanoparticles technique. It has been studied the effect of adding specified types and concentrations of nanoparticles to polymeric materials such as PVC for controlling on electric and dielectric performance. Prediction of effective dielectric constant has been done for the new nanocomposites based on Interphase Power Law (IPL) model. The multi-nanoparticles technique has been succeeded for enhancing electric and dielectric performance of power cables insulation compared with adding individual nanoparticles. Finally, it has been investigated on electric field distribution in the new proposed modern insulations for three-phase core belted power cables. This research has focused on studying development of PVC nanocomposite materials performance with electric field distribution superior to the unfilled matrix, and has stressed particularly the effect of filler volume fraction on the electric field distribution.
Study of hlgs and transfer integrals of dna bases for investigating charge co...IAEME Publication
This document summarizes a study investigating the charge transport properties of DNA bases through calculation of their molecular orbital energies, transfer integrals, and HOMO-LUMO gaps. The key points are:
1) Molecular orbital energies of adenine, guanine, thymine and cytosine were calculated using Gaussian 03 to derive transfer integrals and HOMO-LUMO gaps.
2) Transfer integrals indicate guanine has the highest probability for hole transport while cytosine has the highest for electron transport.
3) All DNA bases have HOMO-LUMO gaps much larger than thermal energy, showing they are suitable for use in nanoelectronic devices at room temperature.
The document describes a study that uses design of experiments (DoE) to optimize slurry-cast cathodes for solid-state batteries. Various combinations of polymer binder type and content and conductive carbon additive type and content were tested as cathode composites. Electrochemical and mechanical performance data from the experiments were analyzed using statistical software to identify optimal combinations. The predictions identified polyisobutene as the best binder and vapor-grown carbon fibers as the best additive to maximize specific capacity. Hydrogenated nitrile butadiene rubber and vapor-grown carbon fibers provided the best combination to maximize capacity retention. Additional tests were conducted to understand changes during cycling.
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 discusses dielectric materials and their applications. It begins by defining dielectrics as insulating materials that can be polarized by an electric field. Dielectrics are then classified into different types including bulk crystals, ceramics, polymers and nano dielectrics. The document also covers the properties of good dielectric materials and discusses their polarization and dielectric constants. It then focuses on applications of dielectrics and microwaves in areas like heating, communications, industry and medicine. In conclusion, the document reviews several references on the topics of dielectric phenomena in solids and ferroelectric devices.
This document summarizes manipulation strategies for two-dimensional amorphous nanomaterials (2D ANMs) to enhance their performance in electrochemical energy storage and conversion applications. It discusses two main categories of manipulation: 1) geometric configuration design, including spatial structure design (e.g. creating porous structures) and coordination environment design (e.g. defect creation); and 2) component interaction, including elemental doping/coupling and heterophase compositing. Recent examples manipulating 2D ANMs through these approaches for applications in batteries, supercapacitors and electrocatalysis are reviewed. The document concludes by discussing opportunities to further optimize manipulation of 2D ANMs.
Recent progress in non platinum counter electrode materials for dye sensitize...Science Padayatchi
Dye-sensitized solar cells (DSSCs) have gained increasing attention
with regard to photovoltaic devices, because of their low
cost and simple fabrication methods; they are mostly investigated
in indoor light-harvesting and portable applications. The
focus has been on three main parameters of photovoltaic devices,
that is, lifetime, and cost effectiveness. A DSSC consists of
four prominent components including a photoanode, a photosensitizer,
a redox electrolyte, and a counter electrode. The
counter electrode is a crucial component, in which triiodide is
reduced to iodide by electrons flowing through the external
circuit. An effective approach to improve the performance of
a counter electrode is to enhance the power conversion efficiency
and to reduce the cost of the device. Platinum-coated
conducting glass electrodes give the best performance, but
their high cost and the scarcity of platinum restricts large-scale
application in DSSCs. This has prompted researchers to develop
low-costing platinum-free electrodes for DSSCs. In this
review, we focus mainly on counter electrode materials for the
electrocatalytic redox reaction for the I¢/I¢
3 electrolyte, and
apart from this, other counter electrode materials for iodinefree
redox electrolytes are discussed. Different counter electrode
materials are highlighted in different categories such as
carbon materials, conducting polymers, oxide and sulfide materials,
transition-metal nitrides and carbides, and composite
materials. The stability of counter electrodes in DSSCs is also
presented.
This document reports on a project to measure the dielectric properties of materials at microwave frequencies. It discusses key concepts such as dielectric constant, permittivity, permeability, Maxwell's equations and how they relate to a material's ability to store and transmit electromagnetic energy. It describes measurement techniques using resonant cavities and waveguides to characterize a material's dielectric constant and loss factor. Sample preparation and ensuring uniform temperature and moisture conditions are important. Both resonant cavity and transmission line methods are covered, with cavity methods noted as providing higher accuracy for loss measurements.
Recent progress in non platinum counter electrode materials for dye sensitize...Science Padayatchi
This document discusses recent progress in developing non-platinum counter electrode materials for dye-sensitized solar cells (DSSCs). It reviews various platinum-free materials that have been studied as alternatives to the traditionally used platinum counter electrodes in DSSCs. These include carbon-based materials like graphene and carbon nanotubes, conducting polymers, metal oxides and sulfides, transition metal nitrides and carbides, and composite materials. The document analyzes the advantages of these materials and their potential to lower the cost of DSSCs while maintaining good performance compared to expensive platinum electrodes.
This document summarizes research on inkjet printing graphene electrodes for flexible micro-supercapacitors. Key points:
- Graphene oxide dispersed in water was found to be a stable ink for inkjet printing graphene electrodes with 50 μm resolution. Thermal reduction produced conductive graphene.
- Initial electrochemical tests showed specific capacitance of 48-132 F/g and energy density of 6.74 Wh/kg, comparable to other graphene electrodes. Power density was lower at 2.19 kW/kg.
- Current work aims to increase capacitance by controlling graphene stacking and morphology, and integrate printed electrodes into micro-supercapacitor devices for flexible electronics applications.
This document provides an overview of coupled mechanical-electrochemical-thermal modeling efforts for lithium-ion batteries being conducted at the National Renewable Energy Laboratory. The modeling aims to better understand the complex interactions between different physical phenomena occurring at different scales in batteries, in order to accelerate the design of improved batteries for electric vehicles. NREL has developed a multi-physics, multi-scale modeling framework called MSMD that accounts for electrochemical, electrical, thermal, chemical, and mechanical effects. The modeling work has included evaluating the impact of battery design parameters, understanding non-uniform utilization, and developing computer-aided engineering tools to simulate battery performance, life, and safety. Recent efforts have focused on coupled mechanical-electrochemical
This document provides an overview of semiconductor theory and electronic devices and circuits. It discusses atomic structure, energy band theory, insulators, semiconductors and metals. It describes charge densities in semiconductors, the Fermi level, drift and diffusion currents, and the Hall effect. It also includes sample assignments and analysis of past GATE exam questions related to electronic devices.
When a dielectric material is placed between the plates of a capacitor, the capacitance increases. This is because the dielectric material becomes polarized in the electric field, resulting in a net separation of positive and negative charges. The polarization is represented by a vector quantity P called the polarization vector. The relative permittivity εr of a material quantifies how much more charge can be stored in a capacitor due to the presence of that material. In covalent solids, electronic polarization occurs due to the displacement of electrons in covalent bonds between atoms in response to an applied electric field.
This document provides an introduction to dielectric materials and their importance in modern technology. It discusses the early history and development of the field, including Faraday's discovery of dielectric polarization and Debye's theory relating molecular dipole moments to macroscopic dielectric properties. Modern applications demand materials with specific dielectric properties tailored for uses like integrated circuits, wireless communication technologies, and microwave devices. The document outlines the classical theory of dielectrics, including the different polarization mechanisms (electronic, atomic/ionic, dipolar/orientational, space charge) that contribute to a material's overall dielectric constant and frequency-dependent behavior.
The Effect of Plasma-Treated Boron Nitride on Partial Discharge Characteristi...IJECEIAES
Power supply reliability is a key factor in a country economic stability. It is contributed by the reliable power distributor via transmission lines, overhead or underground cables. However, the power cables and accessories are always exposed to pre-breakdown phenomena known as partial discharges (PD) which commonly occur in microvoids, defects or protrusions inside the insulation.To improve the performance of the cable insulation against PD, nanofillers are added into the insulating materials. However, to achieve superior performance of PD resistance, the nanofillers must be homogeneously dispersed into the polymer matrices withtightly bonded interfacial zones. Therefore, this could be achieved by employing method of surface functionalization by using cold atmospheric plasma to strengthen the filler/polymer interfaces. In view of foregoing, this study investigated the effects of surface treated boron nitride (BN) nanoparticles in Low Density Polyethylene (LDPE) on the PD characteristics by following CIGRE Method II at 7 kVrmsapplied voltage. The phase resolved PD characteristics were performed. The results revealed that by treating the nanofillers with cold plasma, the PD resistance of LDPE were highly achieved compared with the untreated BN nanofillers.
1. The document discusses different types of magnetic and dielectric materials.
2. It covers topics like diamagnetic, paramagnetic, ferromagnetic materials as well as dielectrics and their polarization mechanisms.
3. The key concepts discussed are magnetic susceptibility, permeability, polarization, dielectric constant and different phenomena exhibited by materials when subjected to electric or magnetic fields.
Dielectric property of chromium oxide nanoparticlesGaurav Yogesh
This document discusses the dielectric properties of chromium oxide (Cr2O3) nanoparticles. It begins with introductions to dielectric materials and different types of polarization that can occur in dielectrics. It then discusses concepts such as complex permittivity, dielectric loss, and loss tangent. The document notes that Cr2O3 nanoparticles have a frequency-dependent dielectric constant and describes some potential applications of Cr2O3 and dielectric materials more broadly, such as in capacitors, coatings, and transformers.
The document reports on a study of the AC and DC conductivity of three glycine family nonlinear optical (NLO) single crystals: Trisglycine Zinc Chloride (TGZC), Triglycine Acetate (TGAc), and Glycine Lithium Sulphate (GLS). The AC conductivity was measured from 50 Hz to 5 MHz and increased with temperature for all crystals. The activation energies calculated from the AC conductivity were 0.035 eV for TGZC, 0.075 eV for TGAc, and 0.10 eV for GLS. The DC conductivity also increased with temperature from 313 K to 423 K, and the activation energies calculated were 0.050 eV for TGZC, 0.060 eV
Dielectric Spectroscopy in Time and Frequency DomainGirish Gupta
This presentation describes the basics and technicalities of Dielectric Spectroscopy in both time and frequency domain. IT also includes the procedure and results involved in Dielectric Spectroscopy on different dielectrics.
Optimization of electric energy density in epoxy aluminium nanocompositeiaemedu
This document summarizes research on optimizing the electric energy density of epoxy-aluminum nanocomposites. It models the nanocomposite as a three-phase material and evaluates how aluminum particle size and filler loading affect permittivity, breakdown strength, and energy density. Numerical results show permittivity increases drastically near the percolation threshold. As filler volume increases, breakdown strength decreases but energy density notably increases. The optimal filler size and concentration for maximum energy density are evaluated, with inter-particle distance controlling breakdown strength significantly impacting energy storage capacity.
Vineet Jagadeesan Nair designed and tested dye-sensitized solar cells using novel organic dye sensitizers to improve power conversion efficiency and long-term stability. Through co-sensitization techniques and material optimizations, a champion efficiency of over 9% was achieved. Organic dyes offer advantages over traditional ruthenium-based dyes such as lower cost and easier synthesis, but have disadvantages including weaker light absorption and shorter exciton lifetimes. Co-sensitization of dyes with complementary absorption spectra can improve overall light harvesting.
1. The document describes a new nanohybrid material composed of polyoxomolybdate, polypyrrole, and graphene oxide for use as a high-power symmetric supercapacitor electrode.
2. The nanohybrid was synthesized via a one-pot reaction where polyoxomolybdate acted as an oxidizing agent to polymerize pyrrole monomers onto graphene oxide nanosheets.
3. Structural and morphological analysis showed the nanohybrid had an excellent architecture with good interfacial contact between components, enabling fast redox reactions for high capacitive performance.
Performance comparison of selection nanoparticles for insulation of three cor...IJECEIAES
This paper presents an investigation on the enhancement of electrical insulations of power cables materials using a new multi-nanoparticles technique. It has been studied the effect of adding specified types and concentrations of nanoparticles to polymeric materials such as PVC for controlling on electric and dielectric performance. Prediction of effective dielectric constant has been done for the new nanocomposites based on Interphase Power Law (IPL) model. The multi-nanoparticles technique has been succeeded for enhancing electric and dielectric performance of power cables insulation compared with adding individual nanoparticles. Finally, it has been investigated on electric field distribution in the new proposed modern insulations for three-phase core belted power cables. This research has focused on studying development of PVC nanocomposite materials performance with electric field distribution superior to the unfilled matrix, and has stressed particularly the effect of filler volume fraction on the electric field distribution.
Study of hlgs and transfer integrals of dna bases for investigating charge co...IAEME Publication
This document summarizes a study investigating the charge transport properties of DNA bases through calculation of their molecular orbital energies, transfer integrals, and HOMO-LUMO gaps. The key points are:
1) Molecular orbital energies of adenine, guanine, thymine and cytosine were calculated using Gaussian 03 to derive transfer integrals and HOMO-LUMO gaps.
2) Transfer integrals indicate guanine has the highest probability for hole transport while cytosine has the highest for electron transport.
3) All DNA bases have HOMO-LUMO gaps much larger than thermal energy, showing they are suitable for use in nanoelectronic devices at room temperature.
The document describes a study that uses design of experiments (DoE) to optimize slurry-cast cathodes for solid-state batteries. Various combinations of polymer binder type and content and conductive carbon additive type and content were tested as cathode composites. Electrochemical and mechanical performance data from the experiments were analyzed using statistical software to identify optimal combinations. The predictions identified polyisobutene as the best binder and vapor-grown carbon fibers as the best additive to maximize specific capacity. Hydrogenated nitrile butadiene rubber and vapor-grown carbon fibers provided the best combination to maximize capacity retention. Additional tests were conducted to understand changes during cycling.
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 discusses dielectric materials and their applications. It begins by defining dielectrics as insulating materials that can be polarized by an electric field. Dielectrics are then classified into different types including bulk crystals, ceramics, polymers and nano dielectrics. The document also covers the properties of good dielectric materials and discusses their polarization and dielectric constants. It then focuses on applications of dielectrics and microwaves in areas like heating, communications, industry and medicine. In conclusion, the document reviews several references on the topics of dielectric phenomena in solids and ferroelectric devices.
This document summarizes manipulation strategies for two-dimensional amorphous nanomaterials (2D ANMs) to enhance their performance in electrochemical energy storage and conversion applications. It discusses two main categories of manipulation: 1) geometric configuration design, including spatial structure design (e.g. creating porous structures) and coordination environment design (e.g. defect creation); and 2) component interaction, including elemental doping/coupling and heterophase compositing. Recent examples manipulating 2D ANMs through these approaches for applications in batteries, supercapacitors and electrocatalysis are reviewed. The document concludes by discussing opportunities to further optimize manipulation of 2D ANMs.
Recent progress in non platinum counter electrode materials for dye sensitize...Science Padayatchi
Dye-sensitized solar cells (DSSCs) have gained increasing attention
with regard to photovoltaic devices, because of their low
cost and simple fabrication methods; they are mostly investigated
in indoor light-harvesting and portable applications. The
focus has been on three main parameters of photovoltaic devices,
that is, lifetime, and cost effectiveness. A DSSC consists of
four prominent components including a photoanode, a photosensitizer,
a redox electrolyte, and a counter electrode. The
counter electrode is a crucial component, in which triiodide is
reduced to iodide by electrons flowing through the external
circuit. An effective approach to improve the performance of
a counter electrode is to enhance the power conversion efficiency
and to reduce the cost of the device. Platinum-coated
conducting glass electrodes give the best performance, but
their high cost and the scarcity of platinum restricts large-scale
application in DSSCs. This has prompted researchers to develop
low-costing platinum-free electrodes for DSSCs. In this
review, we focus mainly on counter electrode materials for the
electrocatalytic redox reaction for the I¢/I¢
3 electrolyte, and
apart from this, other counter electrode materials for iodinefree
redox electrolytes are discussed. Different counter electrode
materials are highlighted in different categories such as
carbon materials, conducting polymers, oxide and sulfide materials,
transition-metal nitrides and carbides, and composite
materials. The stability of counter electrodes in DSSCs is also
presented.
This document reports on a project to measure the dielectric properties of materials at microwave frequencies. It discusses key concepts such as dielectric constant, permittivity, permeability, Maxwell's equations and how they relate to a material's ability to store and transmit electromagnetic energy. It describes measurement techniques using resonant cavities and waveguides to characterize a material's dielectric constant and loss factor. Sample preparation and ensuring uniform temperature and moisture conditions are important. Both resonant cavity and transmission line methods are covered, with cavity methods noted as providing higher accuracy for loss measurements.
Recent progress in non platinum counter electrode materials for dye sensitize...Science Padayatchi
This document discusses recent progress in developing non-platinum counter electrode materials for dye-sensitized solar cells (DSSCs). It reviews various platinum-free materials that have been studied as alternatives to the traditionally used platinum counter electrodes in DSSCs. These include carbon-based materials like graphene and carbon nanotubes, conducting polymers, metal oxides and sulfides, transition metal nitrides and carbides, and composite materials. The document analyzes the advantages of these materials and their potential to lower the cost of DSSCs while maintaining good performance compared to expensive platinum electrodes.
This document summarizes research on inkjet printing graphene electrodes for flexible micro-supercapacitors. Key points:
- Graphene oxide dispersed in water was found to be a stable ink for inkjet printing graphene electrodes with 50 μm resolution. Thermal reduction produced conductive graphene.
- Initial electrochemical tests showed specific capacitance of 48-132 F/g and energy density of 6.74 Wh/kg, comparable to other graphene electrodes. Power density was lower at 2.19 kW/kg.
- Current work aims to increase capacitance by controlling graphene stacking and morphology, and integrate printed electrodes into micro-supercapacitor devices for flexible electronics applications.
This document provides an overview of coupled mechanical-electrochemical-thermal modeling efforts for lithium-ion batteries being conducted at the National Renewable Energy Laboratory. The modeling aims to better understand the complex interactions between different physical phenomena occurring at different scales in batteries, in order to accelerate the design of improved batteries for electric vehicles. NREL has developed a multi-physics, multi-scale modeling framework called MSMD that accounts for electrochemical, electrical, thermal, chemical, and mechanical effects. The modeling work has included evaluating the impact of battery design parameters, understanding non-uniform utilization, and developing computer-aided engineering tools to simulate battery performance, life, and safety. Recent efforts have focused on coupled mechanical-electrochemical
This document provides an overview of semiconductor theory and electronic devices and circuits. It discusses atomic structure, energy band theory, insulators, semiconductors and metals. It describes charge densities in semiconductors, the Fermi level, drift and diffusion currents, and the Hall effect. It also includes sample assignments and analysis of past GATE exam questions related to electronic devices.
When a dielectric material is placed between the plates of a capacitor, the capacitance increases. This is because the dielectric material becomes polarized in the electric field, resulting in a net separation of positive and negative charges. The polarization is represented by a vector quantity P called the polarization vector. The relative permittivity εr of a material quantifies how much more charge can be stored in a capacitor due to the presence of that material. In covalent solids, electronic polarization occurs due to the displacement of electrons in covalent bonds between atoms in response to an applied electric field.
This document provides an introduction to dielectric materials and their importance in modern technology. It discusses the early history and development of the field, including Faraday's discovery of dielectric polarization and Debye's theory relating molecular dipole moments to macroscopic dielectric properties. Modern applications demand materials with specific dielectric properties tailored for uses like integrated circuits, wireless communication technologies, and microwave devices. The document outlines the classical theory of dielectrics, including the different polarization mechanisms (electronic, atomic/ionic, dipolar/orientational, space charge) that contribute to a material's overall dielectric constant and frequency-dependent behavior.
The Effect of Plasma-Treated Boron Nitride on Partial Discharge Characteristi...IJECEIAES
Power supply reliability is a key factor in a country economic stability. It is contributed by the reliable power distributor via transmission lines, overhead or underground cables. However, the power cables and accessories are always exposed to pre-breakdown phenomena known as partial discharges (PD) which commonly occur in microvoids, defects or protrusions inside the insulation.To improve the performance of the cable insulation against PD, nanofillers are added into the insulating materials. However, to achieve superior performance of PD resistance, the nanofillers must be homogeneously dispersed into the polymer matrices withtightly bonded interfacial zones. Therefore, this could be achieved by employing method of surface functionalization by using cold atmospheric plasma to strengthen the filler/polymer interfaces. In view of foregoing, this study investigated the effects of surface treated boron nitride (BN) nanoparticles in Low Density Polyethylene (LDPE) on the PD characteristics by following CIGRE Method II at 7 kVrmsapplied voltage. The phase resolved PD characteristics were performed. The results revealed that by treating the nanofillers with cold plasma, the PD resistance of LDPE were highly achieved compared with the untreated BN nanofillers.
1. The document discusses different types of magnetic and dielectric materials.
2. It covers topics like diamagnetic, paramagnetic, ferromagnetic materials as well as dielectrics and their polarization mechanisms.
3. The key concepts discussed are magnetic susceptibility, permeability, polarization, dielectric constant and different phenomena exhibited by materials when subjected to electric or magnetic fields.
Dielectric property of chromium oxide nanoparticlesGaurav Yogesh
This document discusses the dielectric properties of chromium oxide (Cr2O3) nanoparticles. It begins with introductions to dielectric materials and different types of polarization that can occur in dielectrics. It then discusses concepts such as complex permittivity, dielectric loss, and loss tangent. The document notes that Cr2O3 nanoparticles have a frequency-dependent dielectric constant and describes some potential applications of Cr2O3 and dielectric materials more broadly, such as in capacitors, coatings, and transformers.
The document reports on a study of the AC and DC conductivity of three glycine family nonlinear optical (NLO) single crystals: Trisglycine Zinc Chloride (TGZC), Triglycine Acetate (TGAc), and Glycine Lithium Sulphate (GLS). The AC conductivity was measured from 50 Hz to 5 MHz and increased with temperature for all crystals. The activation energies calculated from the AC conductivity were 0.035 eV for TGZC, 0.075 eV for TGAc, and 0.10 eV for GLS. The DC conductivity also increased with temperature from 313 K to 423 K, and the activation energies calculated were 0.050 eV for TGZC, 0.060 eV
Dielectric Spectroscopy in Time and Frequency DomainGirish Gupta
This presentation describes the basics and technicalities of Dielectric Spectroscopy in both time and frequency domain. IT also includes the procedure and results involved in Dielectric Spectroscopy on different dielectrics.
This document summarizes molecular dynamics simulations of radiation damage in zirconia (ZrO2) at energies ranging from 0.1-0.5 MeV. The simulations find that while zirconia is highly resistant to amorphization, there is still a large number of point defects and small defect clusters created by the radiation. However, these defects are isolated from each other, resulting in dilute damage that does not disrupt the long-range crystalline structure. The simulations quantify the number of displacements and defects over time and find that electronic energy losses play an important role in the damage evolution. The findings have implications for using zirconia in nuclear waste storage by suggesting radiation can create many point defects even while
Modeling the Dependence of Power Diode on Temperature and RadiationIJPEDS-IAES
A theoretical study had been carried out on the effect of radiation on the
electrical properties of silicon power diodes. Computer program
"PDRAD2015" was developed to solve the diode equations and to
introduce the operating conditions and radiation effects upon its
parameters. Temperature increase interrupts the electrical properties of the
diode in the direction of drop voltage decrease across the p-n junction. The
model was analyzed under the influence of different radiation type (gammarays,
neutrons, protons and electrons) with various dose levels and
energies. The carrier’s diffusion lengths were seriously affected leading
to a large increase in the forward voltage. These effects were found to be
function of radiation type, fluence and energy.
Partially filled electrode for DMF devicesWaleed Salman
This document describes research into partially filled electrodes for digital microfluidic devices. The researchers conducted simulations and experiments to evaluate how reducing the filled area of electrodes affects actuation forces on droplets. The simulations showed that actuation force decreases linearly as electrode fill percentage decreases. However, forces were independent of the vertical location of removed electrode areas. Experiments confirmed that partially filled electrodes can still achieve droplet actuation speeds sufficient for many applications, with frequencies over 10 electrodes per second achieved at 40% fill area. Partially filled electrodes also allow integration of additional on-chip elements and transmission microscopy imaging of droplets.
International Journal of Computational Engineering Research(IJCER)ijceronline
International Journal of Computational Engineering Research(IJCER) is an intentional online Journal in English monthly publishing journal. This Journal publish original research work that contributes significantly to further the scientific knowledge in engineering and Technology.
Electrical discharge machining is basically a non-conventional material removal process which is widely used to produce dies, punches and moulds, finishing parts for aerospace and automotive industry, and surgical components. This process can be successfully employed to machine electrically conductive parts irrespective of their hardness, shape and toughness.
This document summarizes a research paper that proposes using dielectrophoresis in a microfluidic device to separate live and dead biological cells. It describes how an applied non-uniform electric field can induce dipole moments in cells, causing them to be attracted to either high or low field regions depending on their dielectric properties. The document outlines the design of a microfluidic device with a 3D electrode structure intended to exploit these differences and separate live and dead mammalian cells based on their dielectric behavior over 50-70 kHz frequencies.
STUDY OF THE EQUIVALENT CIRCUIT OF A DYESENSITIZED SOLAR CELLSAEIJjournal2
The dye-sensitized solar cells (DSSC) have gained the last decades an important place among photovoltaic technologies due to their low-cost of implementation and their performance, which becomes more efficient. The experimental data for this type of cells are enriched and accumulated quickly, given the enthusiasm for this new technology. The present work treats the equivalent circuit of a dye-sensitized solar cell (DSSC) for a model in an exponential, and by using the results of some works, we shall make a simulation by the software Scilab to obtain the characteristics (I-V), then we will study the influence of every parameter on the curve.
Fabrication and studying the dielectric properties of (polystyrene-copper oxi...journalBEEI
This document summarizes a study that fabricated (polystyrene-copper oxide) nanocomposites for potential piezoelectric applications. Copper oxide nanoparticles were added to polystyrene at concentrations of 0, 4, 8 and 12 wt.%. The dielectric constant, dielectric loss, and AC electrical conductivity increased with higher copper oxide concentrations and increased frequency. The electrical resistance of the nanocomposites decreased with increasing pressure, showing piezoelectric behavior. The nanocomposites showed potential for use in piezoelectric sensors due to their sensitivity to pressure changes.
The document provides an overview of dielectric materials and their importance in modern technology. It discusses the early history and development of the field including key contributions from Faraday, Clausius, Mossotti, Debye and others. Debye developed a theory to explain the dielectric properties of polar materials by accounting for their permanent dipole moments and molecular relaxation processes. The theory was successful for polar liquids but broke down for solids due to interactions between dipoles. Modern applications of dielectric materials continue to demand new materials with tailored properties.
STUDY OF THE EQUIVALENT CIRCUIT OF A DYESENSITIZED SOLAR CELLSAEIJjournal2
The dye-sensitized solar cells (DSSC) have gained the last decades an important place among photovoltaic
technologies due to their low-cost of implementation and their performance, which becomes more efficient.
The experimental data for this type of cells are enriched and accumulated quickly, given the enthusiasm for
this new technology. The present work treats the equivalent circuit of a dye-sensitized solar cell (DSSC) for
a model in an exponential, and by using the results of some works, we shall make a simulation by the
software Scilab to obtain the characteristics (I-V), then we will study the influence of every parameter on
the curve.
International Journal of Engineering and Science Invention (IJESI)inventionjournals
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
This document summarizes a study on the photoelectrochemical properties of nanocrystalline indium selenide (In2Se3) thin films deposited via a chemical bath deposition method. The In2Se3 films exhibited n-type conductivity. Current-voltage measurements in the dark showed non-symmetrical rectifying behavior with a junction ideality factor of 3.85, suggesting the influence of series resistance and structural imperfections. Capacitance-voltage measurements determined a flat band potential of -0.530V versus saturated calomel electrode. Barrier height measurements from reverse saturation current at different temperatures yielded a barrier height. Under 30 mW/cm2 illumination, the cell demonstrated an open circuit voltage of 153mV
This document summarizes a study on the photoelectrochemical properties of nanocrystalline indium selenide (In2Se3) thin films deposited via a chemical bath deposition method. The In2Se3 films exhibited n-type conductivity based on photoelectrochemical characterization including I-V and C-V measurements in dark conditions. These measurements were used to determine properties like the ideality factor, flat band potential, and barrier height. Under illumination, the In2Se3 films showed a maximum power output of 3.1 μW/cm2 with an open circuit voltage of 153 mV and short circuit current of 20 μA.
This study examined the surface area that contributes to current density in microbial electrochemical systems. Experiments used a graphite plate working electrode and Geobacter subterraneus to form biofilms on both sides. Chronoamperometry showed biofilms formed on both sides. Cyclic voltammetry identified a direct electron transfer mechanism with a defined potential. Confocal laser scanning microscopy and modeling found the biofilms were uniformly thick at ~75 μm and contributed equally to the current density of ~2.5 A/m2, demonstrating both sides of a planar electrode can transfer electrons regardless of orientation.
A study on piezoelectric elements and its utility in designingAlexander Decker
The document discusses using piezoelectric elements to power an electronic scale. It begins by introducing piezoelectricity and how mechanical stress can generate electricity in certain materials. It then describes different configurations for piezoelectric elements and experiments testing the voltage output of different numbers of elements connected in series. The experiments found that connecting multiple elements in series increased the steady output voltage. The document proposes using 2-3 sets of 4 piezoelectric elements in parallel to power the electronic scale, with the elements generating sufficient power for the low-voltage electronics.
Effect of calcination on the electrical properties and quantum confinement of...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Effect of calcination on the electrical properties and quantum confinement of...eSAT Journals
Abstract Fe2O3 nanoparticles have been prepared by a simple solvothermal method using a domestic microwave oven. X-ray powder diffraction measurement indicates the amorphous nature of the as-prepared sample. Calcined samples were obtained by annealing the as-prepared sample at different temperatures, viz. 400, 500, 600 and 700oC. Transmission electron microscopic images indicate that all the five samples are spherical in shape. AC electrical measurements were carried out on pelletized samples by the parallel plate capacitor method at various temperatures ranging from 40-130oC and frequencies ranging from 100 Hz -1 MHz. Results indicate low AC electrical conductivities and consequently show the occurrence of nano confined states. The exciton Bohr radii obtained from the dielectric constant values at 40oC temperature and 1 kHz frequency are 41.8, 54.8, 55.3, 56.3 and 27.0 respectively for the as-prepared sample and samples calcined at 400, 500, 600 and 700oC which indicate a strong quantum confinement effect. The impedance spectra observed exhibit non-ideal behavior. Keywords: Semiconductors, Magnetic materials, Nanoparticles, Electrical properties
Electrical transport properties of nanocrystalline and bulk nickel.pdfProximaCentauri15
In this work, the comparative study on the electrical transport properties of nanocrystalline nickel
ferrite (NiFe2O4) and its bulk counterpart has been carried out in detail by using complex impedance
spectroscopy in a wide range of frequencies (100 Hz–1 MHz) and temperatures (40 °C–320 °C). The
dispersive nature of the dielectric constant and loss factor is explained by the Maxwell-Wagner model
and Koop’s phenomenological theory. The value of the dielectric constant for nanocrystalline nickel
ferrite is found to be more as compared to its bulk counterpart. The frequency variation dielectric
permittivity is well fitted with the modified Debye formula, which suggests the presence of multiple
relaxation processes. The temperature dependent ac conductivity follows Jonscher’s universal power
law and reveals the presence of multiple transport mechanisms from small polaron hopping (SPH) to
correlated barrier hopping (CBH) mechanism near 200 °C. The estimated values of Mott parameters
are found to be satisfactory. Thermally activated relaxation phenomena have been confirmed by
scaling curves of imaginary impedance (Z) andmodulus (M). The comparison between the Z and
M spectra indicates that both long-range and short-rangemovement of charge carriers contribute to
dielectric relaxation with short-range charge carriers predominating at low temperatures while longrange
charge carriers are dominating at high temperatures. Analysis of the semicircular arcs of Nyquist
plot indicates the presence of grain boundary contribution to the electrical conduction process for the
nanocrystalline sample at high temperatures. The non-Debye type of relaxation has been examined by
stretching exponential factor (β) which has been estimated by fitting the modifiedKWW
(Kohlrausch-Williams-Watts) equation to the imaginary electric modulus curve. The value of β is
found to be strongly temperature dependent and its value for the nanocrystalline sample is less than
that of the bulk system which is explained on the basis of dipole-dipole interaction.
Similar to Investigation of the Piezoelectric Effect as a Means to Generate X-Rays (20)
Offshore fresh groundwater reserves as a global phenomenonCarlos Bella
There is mounting evidence that vast reserves of fresh and brackish groundwater exist below continental shelves around the world. These offshore fresh groundwater reserves (OFGRs) were formed when sea levels were lower during glacial periods, exposing continental shelf areas that became recharged with precipitation and glacial meltwater. While some OFGRs may still be connected to modern coastal groundwater systems, many appear to be relics of past hydrological conditions and are termed "palaeo-groundwater". The largest documented OFGR is below the New Jersey shelf, where freshwater has been found over 100km offshore. Global occurrences of OFGRs have also been identified through borehole and geophysical data in locations such as the North
Revealing letters in rolled Herculaneum papyri by X-ray phase-contrast imagingCarlos Bella
X-ray phase-contrast tomography was used to read letters hidden inside two unopened Herculaneum papyri without damaging them. In a fragment of one papyrus, two Greek words were identified on a hidden layer. In an intact rolled papyrus, several letter sequences were revealed, including "APN", "HEY", and "KI". This non-destructive technique opens opportunities to read many rolled Herculaneum papyri and enhance knowledge of ancient Greek literature.
Animal behaviour: Incipient tradition in wild chimpanzeesCarlos Bella
This study observed the adoption of a new tool use behavior, moss sponging, by chimpanzees at the Sonso community in Uganda's Budongo Forest. The dominant male was first observed using a moss sponge to drink from a small flooded waterhole. Over the next six days, six other chimpanzees began displaying this behavior after observing the dominant male and female. The researchers used a statistical technique called network-based diffusion analysis to show the spread of this innovation was consistent with social learning along social network pathways, providing the first direct evidence of cultural diffusion in wild chimpanzees.
Cohesive forces prevent the rotational breakup of rubble-pile asteroid (29075...Carlos Bella
1) The asteroid (29075) 1950 DA is rotating faster than would be allowed without cohesive forces, with a rotation period of just over 2 hours.
2) Thermal infrared observations and measurements of its orbital drift were used to determine it has a low bulk density of 1.7 g/cm3, indicating it is a rubble pile asteroid made of smaller pieces held together weakly.
3) For it to retain its fine-grained surface and resist breaking up from centrifugal forces at its rate of rotation, cohesive van der Waals forces between the grains comparable to lunar regolith are required, with a minimum cohesive strength of 64 Pa.
Detection of Radio Emission from FireballsCarlos Bella
This document summarizes the detection of radio emissions from fireballs (very bright meteors) using the Long Wavelength Array radio telescope. A search of over 11,000 hours of all-sky radio images found 49 long-duration radio transients. Ten of these transients correlated spatially and temporally with fireballs detected by an optical meteor monitoring network. This provides evidence that fireballs emit previously undiscovered low frequency radio pulses. Further analysis found characteristics inconsistent with expected radio reflections from meteor trails, suggesting a non-thermal radio emission mechanism from the fireballs. This identifies a new class of natural radio transients and provides a new probe to study meteor physics.
This document is the introduction to The Skeptic Encyclopedia of Pseudoscience. It provides an overview of the encyclopedia, which aims to objectively analyze prominent scientific and pseudoscientific claims. The introduction discusses the relationship between facts and theories in science. It notes that observations must be viewed through theoretical lenses, and references Darwin's view that observations are only useful if they are for or against some view. The introduction also discusses how views of science have changed over time between seeing it as progressively approaching truth, and as a relativistic social construct. It argues the field has moved to a more balanced middle view. The goal of the encyclopedia is to explore the borderlands where theory and data intersect, with the aim of achieving a
Preserved flora and organics in impact melt brecciasCarlos Bella
This document discusses the preservation of organic matter and plant remains in impact melt breccias found in Argentina. Analyses found centimeter-scale leaf fragments encapsulated in the impact glass that exhibited remarkable cellular-level preservation. Organic matter was also detected, including polycyclic aromatic hydrocarbons, alkanes, and pigment-like structures similar to chlorophyll. Heating experiments showed temperatures above 1500°C were required to preserve morphology, suggesting the impact process rapidly quenched and encapsulated the organic material. These findings demonstrate the potential for impact events to preserve biomarkers of early life on Mars.
A Sedna-like body with a perihelion of 80 astronomical unitsCarlos Bella
1) The document reports the discovery of 2012 VP113, the second known object after Sedna with an extremely distant perihelion of 80 AU, confirming that Sedna is not isolated.
2) Simulation results suggest there may be few inner Oort cloud objects with perihelia between 50-75 AU, and the population increases with perihelion distances greater than 75 AU.
3) Both Sedna and 2012 VP113 have similar arguments of perihelion, as do all other objects beyond 150 AU, suggesting they were perturbed by a possible unseen super-Earth mass perturber in the outer solar system that could restrict their arguments of perihelion.
Fuel gain exceeding unity in an inertially confined fusion implosionCarlos Bella
The document summarizes key results from experiments achieving fusion fuel gains exceeding unity using a "high-foot" laser pulse shape on the National Ignition Facility. Specifically:
1) Experiments achieved fusion fuel gains over unity for the first time, representing a 10x improvement over past experiments, and showed significant alpha heating and evidence of ignition requirements being met.
2) The "high-foot" pulse shape reduces instability during implosions by increasing ablation velocity and density scale length, improving stability compared to past "low-foot" experiments.
3) Improved performance is attributed to reduced mix from the ablator, with experiments pushing higher velocities through laser power and pattern optimization while maintaining hotspot shape control.
This document summarizes meteor phenomena and bodies. It discusses the different types of interactions that can occur when meteoroids collide with Earth's atmosphere, including meteors, fireballs, bolides, explosive impacts, and meteoric dust particles. It also describes the various stages of a meteoroid's trajectory through the atmosphere, including orbital motion, preheating, ablation, dark flight, and impact. Finally, it provides an overview of the size ranges and velocities associated with different meteor phenomena.
The Origin Of The 1998 June BoöTid Meteor ShowerCarlos Bella
The document analyzes the origin of the 1998 June Boötid meteor shower through comparing orbital elements and simulating particle release from the potential parent comet 7P/Pons–Winnecke. It finds that:
1) 7P/Pons–Winnecke best matches the shower orbit based on the Tisserand invariant and D-discriminant.
2) Simulations show particles released from 7P/Pons–Winnecke in 1819 and 1869 were Earth-crossing in 1998 after Jovian perturbations altered their orbits starting in the 1940s.
3) This identifies 7P/Pons–Winnecke as the parent comet and 1819 and 1869 as the active returns
Physics first spectrum of ball lightningCarlos Bella
Researchers in China measured the first spectrum of ball lightning. They observed ball lightning form after a cloud-to-ground lightning strike about 900 meters away. The spectrum contained emission lines from silicon, iron, and calcium, elements common in soil. This supports the theory that ball lightning is formed when lightning vaporizes soil, producing glowing nanoparticles. It was about 2 meters wide and drifted horizontally for 30 meters before rising a few meters. This is the first direct observation of ball lightning forming from a lightning strike and the first measurement of its emission spectrum.
1) PSR J033711715 is a millisecond pulsar discovered to be in a hierarchical triple system with two white dwarf companions, making it the first known millisecond pulsar triple system.
2) Precise timing observations using multiple radio telescopes determined the masses of the pulsar (1.4378 solar masses), inner white dwarf companion (0.19751 solar masses), and outer white dwarf companion (0.4101 solar masses) to high precision.
3) The unexpectedly coplanar and nearly circular orbits of the system indicate an exotic evolutionary history and provide an opportunity to test theories of general relativity by studying the interactions between the bodies.
Transient Water Vapor at Europa’s South PoleCarlos Bella
1) Hubble Space Telescope images from November and December 2012 of Europa's atmosphere detected statistically significant surpluses of hydrogen Lyman-α and oxygen OI130.4 nm emissions above Europa's southern hemisphere in December 2012.
2) These emissions were observed in the same region over a period of ~7 hours, suggesting an inhomogeneous atmosphere, consistent with two 200-km-high plumes of water vapor with column densities of about 1020 m−2.
3) No plumes were detected in November 2012 images or previous 1999 images, indicating variable plume activity possibly related to Europa's changing orbital phases and surface stresses. The December 2012 plume was seen when Europa was near apocenter.
Solid-state plastic deformation in the dynamic interior of a differentiated a...Carlos Bella
This document summarizes a study that analyzed the microstructural properties of olivine grains in the diogenite meteorite Northwest Africa 5480 using electron backscatter diffraction techniques. The study found evidence of solid-state plastic deformation in the olivine-dominated zones, represented by a well-defined lattice-preferred orientation that is best explained by high-temperature deformation via the pencil-glide slip system, typically seen on Earth in dry ultramafic rocks deformed in the mantle. Numerical modeling indicates this observation in the meteorite can be explained by large-scale downwelling in the asteroid's mantle within the first 50 million years after formation, providing evidence of dynamic planet-like processes occurring in the interior of
Broadband high photoresponse from pure monolayer graphene photodetectorCarlos Bella
This document summarizes a research article that reports on the development of a high-performance photodetector using pure monolayer graphene. The researchers introduced electron trapping centers and created a bandgap in graphene through band structure engineering. This allowed them to achieve a high photoresponsivity of 8.61 A/W, about three orders of magnitude higher than previous graphene photodetectors. Additionally, they demonstrated broadband photoresponse from visible to mid-infrared wavelengths, the broadest reported for a pure graphene photodetector. By introducing defects and quantum confinement effects, they were able to greatly increase the lifetime of photo-generated carriers and achieve carrier multiplication, resulting in high photoresponsivity across a wide spectrum
Formation SiO2 Mass-Independent Oxygen Isotopic Partitioning During Gas-PhaseCarlos Bella
This document summarizes an experimental study that investigated oxygen isotopic partitioning during gas-phase silicon dioxide (SiO2) formation. The experiments involved laser ablation of silicon monoxide (SiO) in the presence of oxygen (O2) with and without hydrogen (H2). SiO2 formed in experiments without H2 showed normal mass-dependent isotopic fractionation, whereas those with H2 exhibited anomalous mass-independent fractionation. The extent of mass-independent fractionation in SiO2 increased with higher H2/O2 ratios. This provides the first experimental evidence that gas-to-particle conversion reactions can produce solids like SiO2 with oxygen isotopic compositions similar to early solar system materials like calcium-
A Complete Skull from Dmanisi, Georgia, and the Evolutionary Biology of Early...Carlos Bella
The article describes a newly discovered complete skull (D4500) from the site of Dmanisi, Georgia dating to 1.8 million years ago. It represents the earliest known completely preserved adult hominin skull. The skull possesses a small braincase of 546 cubic centimeters but also exhibits a large, prognathic face. This combination of features had not been seen before in the human fossil record. Analysis of this new skull and comparison to other remains from Dmanisi provides direct evidence of wide morphological variation within early members of the genus Homo, implying a single evolving lineage across continents.
Minor Planet Evidence for Water in the Rocky Debris of a Disrupted Extrasolar...Carlos Bella
Evidence has been found for water in the debris of a disrupted extrasolar minor planet orbiting a white dwarf star. Spectroscopic analysis of the white dwarf's atmosphere revealed an excess of oxygen that cannot be explained by oxide minerals alone, indicating the parent body was originally composed of about 26% water by mass. This demonstrates that water-bearing planetesimals can form around higher mass stars that eventually become white dwarfs. The disrupted planetesimal is the source of a circumstellar debris disk closely orbiting the white dwarf remnant.
Macroeconomics- Movie Location
This will be used as part of your Personal Professional Portfolio once graded.
Objective:
Prepare a presentation or a paper using research, basic comparative analysis, data organization and application of economic information. You will make an informed assessment of an economic climate outside of the United States to accomplish an entertainment industry objective.
Exploiting Artificial Intelligence for Empowering Researchers and Faculty, In...Dr. Vinod Kumar Kanvaria
Exploiting Artificial Intelligence for Empowering Researchers and Faculty,
International FDP on Fundamentals of Research in Social Sciences
at Integral University, Lucknow, 06.06.2024
By Dr. Vinod Kumar Kanvaria
June 3, 2024 Anti-Semitism Letter Sent to MIT President Kornbluth and MIT Cor...Levi Shapiro
Letter from the Congress of the United States regarding Anti-Semitism sent June 3rd to MIT President Sally Kornbluth, MIT Corp Chair, Mark Gorenberg
Dear Dr. Kornbluth and Mr. Gorenberg,
The US House of Representatives is deeply concerned by ongoing and pervasive acts of antisemitic
harassment and intimidation at the Massachusetts Institute of Technology (MIT). Failing to act decisively to ensure a safe learning environment for all students would be a grave dereliction of your responsibilities as President of MIT and Chair of the MIT Corporation.
This Congress will not stand idly by and allow an environment hostile to Jewish students to persist. The House believes that your institution is in violation of Title VI of the Civil Rights Act, and the inability or
unwillingness to rectify this violation through action requires accountability.
Postsecondary education is a unique opportunity for students to learn and have their ideas and beliefs challenged. However, universities receiving hundreds of millions of federal funds annually have denied
students that opportunity and have been hijacked to become venues for the promotion of terrorism, antisemitic harassment and intimidation, unlawful encampments, and in some cases, assaults and riots.
The House of Representatives will not countenance the use of federal funds to indoctrinate students into hateful, antisemitic, anti-American supporters of terrorism. Investigations into campus antisemitism by the Committee on Education and the Workforce and the Committee on Ways and Means have been expanded into a Congress-wide probe across all relevant jurisdictions to address this national crisis. The undersigned Committees will conduct oversight into the use of federal funds at MIT and its learning environment under authorities granted to each Committee.
• The Committee on Education and the Workforce has been investigating your institution since December 7, 2023. The Committee has broad jurisdiction over postsecondary education, including its compliance with Title VI of the Civil Rights Act, campus safety concerns over disruptions to the learning environment, and the awarding of federal student aid under the Higher Education Act.
• The Committee on Oversight and Accountability is investigating the sources of funding and other support flowing to groups espousing pro-Hamas propaganda and engaged in antisemitic harassment and intimidation of students. The Committee on Oversight and Accountability is the principal oversight committee of the US House of Representatives and has broad authority to investigate “any matter” at “any time” under House Rule X.
• The Committee on Ways and Means has been investigating several universities since November 15, 2023, when the Committee held a hearing entitled From Ivory Towers to Dark Corners: Investigating the Nexus Between Antisemitism, Tax-Exempt Universities, and Terror Financing. The Committee followed the hearing with letters to those institutions on January 10, 202
Biological screening of herbal drugs: Introduction and Need for
Phyto-Pharmacological Screening, New Strategies for evaluating
Natural Products, In vitro evaluation techniques for Antioxidants, Antimicrobial and Anticancer drugs. In vivo evaluation techniques
for Anti-inflammatory, Antiulcer, Anticancer, Wound healing, Antidiabetic, Hepatoprotective, Cardio protective, Diuretics and
Antifertility, Toxicity studies as per OECD guidelines
it describes the bony anatomy including the femoral head , acetabulum, labrum . also discusses the capsule , ligaments . muscle that act on the hip joint and the range of motion are outlined. factors affecting hip joint stability and weight transmission through the joint are summarized.
Introduction to AI for Nonprofits with Tapp NetworkTechSoup
Dive into the world of AI! Experts Jon Hill and Tareq Monaur will guide you through AI's role in enhancing nonprofit websites and basic marketing strategies, making it easy to understand and apply.
MATATAG CURRICULUM: ASSESSING THE READINESS OF ELEM. PUBLIC SCHOOL TEACHERS I...NelTorrente
In this research, it concludes that while the readiness of teachers in Caloocan City to implement the MATATAG Curriculum is generally positive, targeted efforts in professional development, resource distribution, support networks, and comprehensive preparation can address the existing gaps and ensure successful curriculum implementation.
How to Fix the Import Error in the Odoo 17Celine George
An import error occurs when a program fails to import a module or library, disrupting its execution. In languages like Python, this issue arises when the specified module cannot be found or accessed, hindering the program's functionality. Resolving import errors is crucial for maintaining smooth software operation and uninterrupted development processes.
2. GALL et al.: INVESTIGATION OF PIEZOELECTRIC EFFECT AS MEANS TO GENERATE X-RAYS 107
Fig. 1. Bar-shaped piezoelectric material for increasing an applied voltage.
Fig. 2. Simulated voltage gain versus frequency of a lithium niobate bar. Gain
A mass of lithium niobate in the shape of a flat bar is shown is normalized to maximum gain value.
in Fig. 1. A detailed description of the material properties of
lithium niobate can be found in a number of sources [16]–[19].
The primary geometric axes of the bar in Fig. 1 are x1 , x2 , and
x3 , and the secondary axes x2 and x3 are rotated by an angle
θ about the primary axis x1 [20]. This rotation indicates the
crystallographic polarization direction of the lithium niobate.
Input electrodes, shown as gray regions on the top and bottom
(not visible) surfaces of the bar in Fig. 1, are used to deliver
electrical power to the crystal. Electric fields in the x3 -direction
couple into mechanical displacements in the x2 -direction as Fig. 3. Piezoelectric transformer equivalent circuit model.
a result of the rotated polarization, and an output voltage is
produced at the extremity of the bar. This is known as the length
extensional mode [21].
The voltage gain can be maximized by satisfying two criteria.
First, the product of the piezoelectric coupling coefficients
k23 and k33 should be maximized. The value of the product
k22 k32 has been found to be a maximum of approximately 0.3
when the polarization of lithium niobate is rotated by 45◦ [20].
Second, the piezoelectric bar should be driven at or near its
natural mechanical resonance. The resonant frequency ωn is Fig. 4. Experimental setup to generate X-rays using a piezoelectric crystal.
determined by material properties and the dimensions of the
bar, shown in the following [13]: III. E XPERIMENTAL S ETUP
The piezoelectric crystals used in this experiment were
nπ sE
ωn = . (4) 100 mm × 10 mm × 1.5 mm slabs of lithium niobate rotated
l ρ 45◦ about the x1 -axis, as shown in Fig. 1. Electrodes were
applied using silver paint with a measured layer thickness
The variables l, sE , and ρ are the length of the bar in the of approximately 50 μm. High field electron emitters were
x2 -direction, the elasticity tensor, and the density of the ma- fabricated from 0.1-mm-diameter platinum–iridium wire [23],
terial. The integer value n indicates the harmonic mode of cut to approximately 1 mm in length, and adhered to the high-
resonance. The plot in Fig. 2 was generated from solutions of voltage output of the crystal with silver paint. Fig. 4 shows the
a 1-D piezoelectric model based on the material constants for experimental setup for the piezoelectric X-ray source. All ex-
lithium niobate to demonstrate the voltage gain dependence on periments were conducted at pressures below 10−3 torr because
operating frequency [22]. this was the threshold pressure for X-ray production. Finite-
An equivalent circuit model for the piezoelectric transformer element simulations indicated that a maximum mechanical dis-
is shown in Fig. 3. A sinusoidal voltage source Vin drives placement of approximately 10 μm occurred at each extremity
the transformer input, which is modeled as a capacitor Cin of the bar with a displacement null located near its center [24].
representing the capacitance between the two input electrodes. For this reason, the crystal was clamped with an expanded
A step-up transformer models the voltage gain and the isolation polymer sponge at its center to reduce mechanical damping.
between the input and output terminals of the piezoelectric The high voltage at the crystal output was indirectly mea-
transformer. The output of the transformer is modeled as a sured using the bremsstrahlung spectra produced when the
capacitor Cout . The electron beam is modeled as a series of accelerated electron beam struck the stainless steel vacuum
diode and resistor with a parallel capacitor. The output and chamber walls. Electron trajectories were determined using
input of the transformer share a mutual ground. finite-element ray tracing software [24], shown in Fig. 4 as
3. 108 IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 41, NO. 1, JANUARY 2013
TABLE I
P ERTINENT D ECAY P ROPERTIES OF C D -109 AS AN X-R AY
D ETECTOR C ALIBRATION S OURCE
Fig. 6. System diagram for the basic experimental configuration for piezo-
electric crystal operation. (A) Low-voltage ac drive signal at 25–50 mVmax
and 30.7 kHz. (T1 and T2) Falling edge trigger and gate signal for PX4. (B1,
B2, and B3) High-voltage ac drive signal at 10–20 Vmax to Pearson coil,
oscilloscope, and crystal. (D) Crystal-generated X-ray flux. (E) Raw analog
X-ray detector signal. (F) Digital spectrum data.
Fig. 5. Sample calibration spectrum using the CdTe X-ray detector for a
Cd-109 radioisotope calibration source.
dotted lines. Bremsstrahlung interactions occurred at the walls
of the port, and an Amptek XR-100T CdTe γ/X-ray detector
with 1.5-keV FWHM energy resolution and 4.0-μs resolving
time was used to record the X-ray spectra through a 50-μm-
thick aluminum window. A PX4 pulse processor was used to
digitize the spectrum for viewing on a PC. In this configuration,
the noise introduced by the PX4 signal gain was negligible Fig. 7. Input voltage and current traces for a resonating piezoelectric crystal.
because it was several orders of magnitude less than the noise
produced by the CdTe detector itself [25]. The detector was in Fig. 6 shows this setup. An example of a typical resonant
placed very near to this window to maximize the geometric burst pulse used to drive the crystal is shown in Fig. 7. The
efficiency of the detector and increase the signal–noise ratio. input voltage amplitude diminished throughout the pulse, while
The MCA was calibrated using a Spectrum Techniques the input current amplitude increased, an indication that the
1-μCi Cd-109 calibration source for the CdTe X-ray detector. resonant frequency had been reached [13]. The drive frequency
Cd-109 is a convenient choice because it has prominent peaks was in agreement with the modeled resonant frequency in
at 22 and 88 keV, providing an accurate calibration throughout Fig. 2, ranging between 30.6 and 30.9 kHz.
the range of the spectrum [26]. A peak at 24.9 keV was used as a A gate signal was applied to an Amptek PX4 digital pulse
third point to verify the calibration. A lower level discriminator processor in order to decrease the effect of background radi-
was fixed, and the MCA gain was set to 9.1 throughout the ation during sampling intervals. This was done because the
experiment, producing a range of detectable X-ray energy crystal is operated in a pulsed mode with a duty cycle of ap-
from 8 to 140 keV. Table I shows select decay properties of proximately 9% to limit mechanical failure of the crystal [13].
Cd-109. Fig. 5 shows a sample calibration spectrum of the The gate signal pulse is shown in Fig. 7 as an encapsulation of
Cd-109 source. the applied burst pulse and the immediately subsequent ring-
An Agilent 33210A function generator was used to produce down. This portion of the ring-down was arbitrarily defined
the ac voltage to drive the piezoelectric crystal. An Amplifier as the 5 ms after the pulse and was included to count X-rays
Research KAA1020 25-W 43-dB RF power amplifier was used measured during this time. A 90-μs zoomed view shows that the
to amplify the drive voltage to 11–16 Vmax . At drive voltages current and voltage waveforms are in phase with one another at
lower than this range, X-ray production was not observed, and resonance.
at higher voltages, the piezoelectric crystal tended to fracture
due to exceeding the yield strength of lithium niobate (between
IV. R ESULTS
30 and 120 MPa) [19]. A Pearson 2877 current monitor with
1-V/A output sensitivity measured the input current to the X-ray spectra were recorded which demonstrate that a piezo-
crystal. A Tektronix TDS 2024B oscilloscope was used to electric crystal designed to operate in the length extensional
measure crystal input voltage and current. The system diagram mode was capable of producing X-rays with energies up to
4. GALL et al.: INVESTIGATION OF PIEZOELECTRIC EFFECT AS MEANS TO GENERATE X-RAYS 109
Fig. 9. Same spectrum from Test 1 presented in total counts to demonstrate
time-dependent count rate reduction.
Fig. 8. Collection of nine high-energy X-ray tests under a variety of operating
conditions using a piezoelectric crystal. Spectra are presented in counts per output of the piezoelectric crystal and the effective resistance
second, and background was normalized and subtracted from each spectrum.
Duration for each test was between 30 and 60 s.
of the electron beam due to field emitter quality. Models have
shown that this 50-Ω variability in input impedance changes the
TABLE II input power by ±100 mW, in agreement with the experimen-
X-R AY S PECTRUM I NFORMATION FOR F IG .8. D URATION FOR A LL T ESTS tally observed range of input powers. The input voltage varied
I S B ETWEEN 30 AND 60 s. (∗ I NDICATES T EST W ITH
D EUTERIUM BACKGROUND G AS ) between 11 and 16 V in amplitude. Comparing this value with
the X-ray spectrum data in Fig. 8, the maximum measured gain
of the piezoelectric transformer source was between 7.9 and
11.5 kV/V.
An expression for the maximum electron beam current was
computed by applying energy conservation laws to the piezo-
electric transformer. The piezoelectric transformer model is
analogous to that of the conventional magnetic core transformer
such that the output current can be determined if the output
voltage and input power are known, as shown in
Pin = Vout × Iout . (5)
127 keV under several different conditions. A collection of
nine different X-ray spectra are shown in Fig. 8. Table II Using the data from Test 1, the input voltage and current
gives pertinent data for the spectra in Fig. 8 and shows that amplitudes were 16 V and 79 mA, respectively. Converting
high voltage was achieved with various pressures and crystal these values to rms and multiplying yield an input power of
samples. Test 9 shows that the piezoelectric crystal reached 632 mW. The peak output voltage was recorded to be 127 kV
127 keV in a deuterium environment at 770 μtorr, demonstrat- or 89.8 kV rms, and solving for Iout in (5) yields an rms current
ing that the method is viable in low-pressure gas applications. of 7 μA or a peak current of approximately 10 μA.
The spectra were binned to decrease counting error and improve An unexpected observation was made during this experiment
endpoint determination. Some energy resolution is sacrificed regarding the time-dependent X-ray output of the piezoelectric
due to the binning process. As a result, each energy level crystal. It was found that X-ray count rate and maximum
corresponds approximately to a ±7-keV range, and a precise X-ray energy both decreased as testing runtime progressed.
endpoint energy cannot be obtained. However, as the primary This limited data collection to approximately 1 min of active
goal of this work is to verify high-energy X-ray production, this collection time. The spectrum in Fig. 9 was generated from the
reduction of energy resolution is acceptable. spectral data from Test 1, showing the total counts collected
Of the nine spectra shown, five produced X-rays with an within two successive time periods, each lasting 60 s. The iron
endpoint energy of at least 127 keV. The variation in count kα peak of 6.4 keV was visible at both times, but there were two
rate among observations was due to uncontrolled factors such orders of magnitude of separation between the total counts in
as field emitter quality and variability in stray capacitances each of the time periods. The maximum X-ray energy recorded
at the output. Background counts were subtracted from each in the first 60 s reached the 127-keV bin according to Fig. 8,
recorded spectrum, and only statistically significant count rates but Fig. 9 shows that this decreased to about 15 keV in the
are shown. Error bars correspond to one standard deviation of next 60 s.
error and include the propagation of background counting error. One explanation for the decrease in X-ray count rate is
The function generator was fixed at a constant voltage; that electron beam transport discharged the output capacitance
however, input power varied between 312 and 720 mW among of the transformer. The circuit model in Fig. 3 shows that
observations. Modeling has indicated that variations in output a current return path was not available to the output of the
impedance can change the input impedance of the piezoelectric transformer, which prevented charge neutralization at the output
crystal by as much as 50 Ω. This variation in impedance is while the beam was off. Due to the low output capacitance
due to uncontrolled parameters such as stray capacitance at the of the transformer (calculated to be between 0.1 and 1 pF),
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[1] R. Talman, Accelerator X-Ray Sources. Hoboken, NJ: Wiley-VCH,
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electric crystals,” J. Appl. Phys., vol. 97, no. 10, pp. 104 916-1–104 916-5, Brady Gall (S’09) received the B.S. and M.S. de-
May 2005. grees in electrical engineering from the University of
[5] W. Tornow, S. Lynam, and S. Shafroth, “Substantial increase in acceler- Missouri, Columbia, in 2009 and 2012, respectively.
ation potential of pyroelectric crystals,” J. Appl. Phys., vol. 107, no. 6, He is currently a Graduate Research Assistant with
pp. 063302-1–063302-4, Mar. 2010. the Department of Electrical and Computer Engi-
[6] J. Hird, “A triboelectric x-ray source,” Appl. Phys. Lett., vol. 98, no. 13, neering, University of Missouri, under the advise-
pp. 133 501-1–133 501-3, Mar. 2011. ment of Scott D. Kovaleski. His research focuses on
[7] A. Benwell, S. Kovaleski, and M. Kemp, “A resonantly driven piezoelec- the testing and optimization of high-voltage piezo-
tric transformer for high voltage generation,” in Proc. IEEE Int. Power electric sources for the production and acceleration
Modul. High Volt. Conf., May 2008, pp. 113–116. of charged particles.
6. GALL et al.: INVESTIGATION OF PIEZOELECTRIC EFFECT AS MEANS TO GENERATE X-RAYS 111
Scott D. Kovaleski (M’99–SM’09) received the B.S. Baek Hyun Kim (M’11) received the B.A. degree in physics from Chungnam
degree in nuclear engineering from Purdue Univer- National University, Daejeon, Korea, in 2001 and the M.S. and Ph.D. degrees
sity, West Lafayette, IN, and the M.S. and Ph.D. in materials science and engineering from the Gwangju Institute of Science and
degrees in nuclear engineering with a specialty in Technology, Gwangju, Korea, in 2003 and 2008, respectively.
plasma physics from the University of Michigan, In 2008, he joined the Department of Materials Science and Engineering,
Ann Arbor. Carnegie Mellon University, Pittsburgh, PA, as a Postdoctoral Research As-
From the University of Michigan, he moved on sociate. Since 2010, he has been a Postdoctoral Fellow with the Department
to General Electric (GE) Lighting, where he was of Electrical and Computer Engineering, University of Missouri, Columbia.
a Product Scientist working on quartz metal halide His research interests include low-dimensional nanostructures and optical and
arc lamps. From GE Lighting, he became a Con- electrical devices using low-dimensional nanostructures.
tractor with Glenn Research Center, NASA, where Dr. Kim is a member of the Materials Research Society, Korean Physical
he worked on the International Space Station plasma contactor and on ion Society, and Korean Vacuum Society.
propulsion. Since 2003, he has been with the University of Missouri, Columbia,
where he has worked on numerous research projects in the areas of compact
accelerators, plasma and ion sources, electric propulsion, and pulsed power. He Jae Wan Kwon (S’96–M’04) received the B.S. degree in electronics engineer-
and his students have conducted studies in pulsed-power engineering relevant ing from Kyungpook National University, Daegu, Korea, in 1994 and the M.S.
to flashover insulation of high-voltage accurate laser triggering of gas-filled and Ph.D. degrees in electrical engineering from the University of Southern
switches and solid-state pulsed-power switching. He has developed and studied California, Los Angeles, in 1997 and 2004, respectively.
compact ion accelerators and ion sources based on piezoelectric transformer He is currently an Associate Professor with the Department of Electrical and
high-voltage sources for space propulsion and compact neutron generators. His Computer Engineering, University of Missouri, Columbia, where he also holds
research interests include nuclear science, accelerators and plasmas, energetic a courtesy appointment with the Department of Biological Engineering. His
particle sources, and related technologies. research interests include micro-/nanoelectromechanical systems, micro power
Dr. Kovaleski is a member of the American Physical Society and the sources, microfabrication processing technology, piezoelectric transducers, mi-
American Nuclear Society. crofluidic systems, biomedical microsystems, and nanotechnology.
Prof. Kwon was a recipient of the NSF CAREER Award, Missouri Honor
Junior Faculty Research Award, Outstanding Paper Award in the IEEE In-
ternational Conference on Solid-State Sensors, Actuators and Microsystems
James A. VanGordon (S’07) received the B.S. and (Transducers 2009), and the Best New Application Paper Award from IEEE
M.S. degrees in electrical engineering from the Uni- T RANSACTIONS ON AUTOMATION S CIENCE AND E NGINEERING (2006). He
versity of Missouri, Columbia, in 2008 and 2010, has been serving on the Technical Program Committees of the International
respectively, where he is currently working toward Workshop on Micro and Nanotechnology (PowerMEMS), the IEEE Conference
the Ph.D. degree in electrical engineering. on Sensors, and the Hilton Head Solid-State Sensors, Actuators and Microsys-
His research interests include pulsed-power sys- tems Workshop.
tems, power electronics, and high-voltage circuit
design.
Mr. VanGordon is a student member of the Insti- Gregory E. Dale (S’97–M’03) received the B.S. degree in nuclear engineering
tute of Nuclear Materials Management. from The University of New Mexico, Albuquerque, in 1995, the M.S. degree
in nuclear engineering with a minor in physics from North Carolina State
University, Raleigh, in 1998, and the Ph.D. degree in electrical engineering
from the University of Missouri, Columbia, in 2003.
Upon completing his dissertation, he joined Los Alamos National Laboratory
Peter Norgard (S’02–M’09) received the M.S. and Ph.D. degrees in electrical
(LANL), Los Alamos, NM, as a Technical Staff Member developing solid-
engineering from the University of Missouri, Columbia, in 2006 and 2009,
state pulsed-power modulators for compact accelerator systems. He is currently
respectively.
a Project Leader with the High Power Electrodynamics Group, Accelerator
He is currently a Postdoctoral Research Fellow with the University of
and Operations Technology Division, LANL. In this capacity, he is in charge
Missouri, where he is conducting research on ion sources and accelerators and
of several compact radiography, pulsed-power, compact neutron source, and
on electrooptic voltage and current diagnostic techniques.
accelerator production medical radioisotope projects. He has experience in
experimental research, solid-state modulators, electron accelerators, nuclear
medicine, radiography, electrothermal plasma guns, first-wall components in
tokamak fusion reactors, radiation shielding, and radiation detection.
Andrew Benwell (M’09), photograph and biography not available at the time Dr. Dale serves on the Executive Committee of the International Power
of publication. Modulator and High Voltage Conference.