The strontium bismuth niobate, SrBi2Nb2O9 (SBN) is a bismuth layered perovskite oxide
compound with potentially useful ferroelectric properties which offer several advantages such as fatigue
free, lead free, low operating voltages, relatively high Curie temperature; and most importantly, their
ferroelectric properties are independent of film thickness. These materials are also important for Fe-RAM
applications having large remanent polarization and low coercivity accompanied by high Curie
temperature for better performance and reliable operation. Present paper describes synthesis, dielectric
properties and impedance studies to reveal the important properties of barium substituted strontium
bismuth niobate, Sr0.85Ba0.15Bi2Nb2O9 in the system Sr1-xBaxBi2Nb2O9(x=0.15).
Space charge and dielectric behavior of epoxy composite with si o2 al2o3 nano...Oussama Elbouadi
The document discusses a study of the space charge distribution, complex dielectric permittivity, and conduction current of an epoxy resin and its composite with SiO2-Al2O3 nano-micro fillers at temperatures ranging from 20 to 200°C. The results show that below the glass transition temperature (Tg), space charge behavior is dominated by electronic charge transport, while above Tg it is dominated by ion transport. Both the real and imaginary parts of complex permittivity increase dramatically above Tg, which can be attributed to ion accumulation at the electrodes. The conduction current also increases with temperature and transitions from electronic to ionic charge transport above Tg. The composite exhibits weaker space charge accumulation, lower complex permit
The document summarizes a study on the effect of In, Ce, and Bi dopings on sintering and dielectric properties of Ba(Zn1/3Nb2/3)O3 (BZN) ceramics. In doping between 0.2-4.0% increased density at 1300°C. Ce doping decreased density at 1250°C. Bi doping up to 1.0% negatively affected densification, while higher levels improved it. XRD showed single phase formation for all dopant levels except 0.5% Bi. In and Ce doping increased dielectric constant from 41 to around 66 at 1 MHz. Bi doping initially decreased then increased dielectric constant with higher levels.
Dielectric, Electric and Thermal Behavior of La3+ doped Co-Zn NanoferriteIOSRJAP
Dielectric, Electric and Thermal properties of rare earth La3+ material doped in Co0.5Zn0.5 Lax Fe(2- x)O4 (where x=0.025, 0.050, 0.075, 0.100, 0.125) reaction nanocrystalline ferrites were synthesized by sol-gel auto combustion method. The electric, dielectric constant and Thermal properties were investigated. The dielectric constants and dielectric loss of the samples was observed between the 100Hz and 5 MHz. The resistivities of the prepared samples were measured from 0 Volt to 550 Volts at the constant temperature 2000C using the Two Probe method. The Thermal properties were characterized by Thermo Gravimetric and Differential Thermal Analysis (TGDTA).
Electrical properties of Ni0.4Mg0.6Fe2O4 ferritesIJERA Editor
Ni0.4Mg0.6Fe2O4 Ceramic samples were prepared by conventional double sintering approach and sintered at 1300oC/4 h. These ferrites are further characterized using X-ray diffractometer. The diffraction study reveals that the present compound shows perfect single phase cubic spinel structure. In addition, the behavior of distinct electrical properties such as dielectric constant (ε'), dielectric loss (ε") and ac-conductivity (ζac) as a function frequency as well as temperature is analyzed using the LCR controller.
A Study of Electrical and Magnetic Properties of La+3 Substituted Ni-Zn Ferritesiosrjce
IOSR Journal of Applied Physics (IOSR-JAP) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of physics and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in applied physics. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Characterisation of MCT using hall effectMahesh Negi
This document provides information about characterizing mercury cadmium telluride (MCT) using the Hall effect measurement technique. It first introduces semiconductors and discusses their intrinsic and extrinsic properties. It then describes the properties and applications of MCT, an important infrared detector material. The document also explains molecular beam epitaxy (MBE), the technique used to grow high-quality MCT epitaxial layers. MBE involves heating elements in separate cells to form atomic or molecular beams that interact on a heated crystalline substrate. Finally, the document lists several characterization techniques, including Hall effect, that can be used to analyze the properties of MCT materials grown by MBE.
1. A melt spinning and spark plasma sintering (MS-SPS) process was used to prepare n-type Bi2(Te1-xSex)3 (x = 0.0-1.0) solid solutions from high purity elemental chunks.
2. Substitution of tellurium with selenium significantly impacted the electrical and thermal transport properties in a way that can be understood using valence bond rules and changes in band gap.
3. The Bi2(Se0.2Te0.8)3 sample achieved the highest ZT of 1.05 at 420K, with an average ZT of around 0.97 in the entire measurement temperature range from 300-500K, representing
This document discusses a study on the effect of curing on the activation energy and dielectric properties of carbon black-epoxy composites at different temperatures and frequencies. The key findings are:
1) The activation energy was found to be higher for room temperature cured carbon black-epoxy samples compared to thermally cured samples, indicating curing behavior affects activation energy.
2) Dielectric constants of thermally cured samples were higher than room temperature cured samples.
3) Activation energy decreased with increasing carbon black concentration in the composite, likely due to increased polarization energy and charge carrier density.
4) Dielectric constant increased with temperature but decreased with increasing frequency for both cured sample types.
Space charge and dielectric behavior of epoxy composite with si o2 al2o3 nano...Oussama Elbouadi
The document discusses a study of the space charge distribution, complex dielectric permittivity, and conduction current of an epoxy resin and its composite with SiO2-Al2O3 nano-micro fillers at temperatures ranging from 20 to 200°C. The results show that below the glass transition temperature (Tg), space charge behavior is dominated by electronic charge transport, while above Tg it is dominated by ion transport. Both the real and imaginary parts of complex permittivity increase dramatically above Tg, which can be attributed to ion accumulation at the electrodes. The conduction current also increases with temperature and transitions from electronic to ionic charge transport above Tg. The composite exhibits weaker space charge accumulation, lower complex permit
The document summarizes a study on the effect of In, Ce, and Bi dopings on sintering and dielectric properties of Ba(Zn1/3Nb2/3)O3 (BZN) ceramics. In doping between 0.2-4.0% increased density at 1300°C. Ce doping decreased density at 1250°C. Bi doping up to 1.0% negatively affected densification, while higher levels improved it. XRD showed single phase formation for all dopant levels except 0.5% Bi. In and Ce doping increased dielectric constant from 41 to around 66 at 1 MHz. Bi doping initially decreased then increased dielectric constant with higher levels.
Dielectric, Electric and Thermal Behavior of La3+ doped Co-Zn NanoferriteIOSRJAP
Dielectric, Electric and Thermal properties of rare earth La3+ material doped in Co0.5Zn0.5 Lax Fe(2- x)O4 (where x=0.025, 0.050, 0.075, 0.100, 0.125) reaction nanocrystalline ferrites were synthesized by sol-gel auto combustion method. The electric, dielectric constant and Thermal properties were investigated. The dielectric constants and dielectric loss of the samples was observed between the 100Hz and 5 MHz. The resistivities of the prepared samples were measured from 0 Volt to 550 Volts at the constant temperature 2000C using the Two Probe method. The Thermal properties were characterized by Thermo Gravimetric and Differential Thermal Analysis (TGDTA).
Electrical properties of Ni0.4Mg0.6Fe2O4 ferritesIJERA Editor
Ni0.4Mg0.6Fe2O4 Ceramic samples were prepared by conventional double sintering approach and sintered at 1300oC/4 h. These ferrites are further characterized using X-ray diffractometer. The diffraction study reveals that the present compound shows perfect single phase cubic spinel structure. In addition, the behavior of distinct electrical properties such as dielectric constant (ε'), dielectric loss (ε") and ac-conductivity (ζac) as a function frequency as well as temperature is analyzed using the LCR controller.
A Study of Electrical and Magnetic Properties of La+3 Substituted Ni-Zn Ferritesiosrjce
IOSR Journal of Applied Physics (IOSR-JAP) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of physics and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in applied physics. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Characterisation of MCT using hall effectMahesh Negi
This document provides information about characterizing mercury cadmium telluride (MCT) using the Hall effect measurement technique. It first introduces semiconductors and discusses their intrinsic and extrinsic properties. It then describes the properties and applications of MCT, an important infrared detector material. The document also explains molecular beam epitaxy (MBE), the technique used to grow high-quality MCT epitaxial layers. MBE involves heating elements in separate cells to form atomic or molecular beams that interact on a heated crystalline substrate. Finally, the document lists several characterization techniques, including Hall effect, that can be used to analyze the properties of MCT materials grown by MBE.
1. A melt spinning and spark plasma sintering (MS-SPS) process was used to prepare n-type Bi2(Te1-xSex)3 (x = 0.0-1.0) solid solutions from high purity elemental chunks.
2. Substitution of tellurium with selenium significantly impacted the electrical and thermal transport properties in a way that can be understood using valence bond rules and changes in band gap.
3. The Bi2(Se0.2Te0.8)3 sample achieved the highest ZT of 1.05 at 420K, with an average ZT of around 0.97 in the entire measurement temperature range from 300-500K, representing
This document discusses a study on the effect of curing on the activation energy and dielectric properties of carbon black-epoxy composites at different temperatures and frequencies. The key findings are:
1) The activation energy was found to be higher for room temperature cured carbon black-epoxy samples compared to thermally cured samples, indicating curing behavior affects activation energy.
2) Dielectric constants of thermally cured samples were higher than room temperature cured samples.
3) Activation energy decreased with increasing carbon black concentration in the composite, likely due to increased polarization energy and charge carrier density.
4) Dielectric constant increased with temperature but decreased with increasing frequency for both cured sample types.
Reflectance and photoluminescence characterization of BexZn1Oleg Maksimov
This document summarizes research on the optical properties of BexZn1-xTe thin films grown by molecular beam epitaxy. Reflectance and photoluminescence measurements were performed on the epilayers as a function of BeTe content and temperature. An increase in emission line broadening was observed with higher BeTe content, which is attributed to alloy disorder. Temperature-dependent reflectance data showed a reduction in the variation of band gap energy with increasing BeTe content. This effect is proposed to be due to lattice hardening from BeTe decreasing the lattice contribution to the temperature dependence.
This document summarizes research on the electrical conductivity of Ba-Sr-Co-Fe cathode materials for solid oxide fuel cells (SOFCs). Single phase cubic Ba0.5Sr0.5Co1-xFexO3-δ compositions were synthesized via gel combustion and cation complexation routes. Electrical conductivity measurements showed that conductivity initially increased with temperature up to a maximum then decreased, attributed to oxygen loss from the lattice. Fe substitution had little effect on conductivity. While BSCF shows potential as an SOFC cathode, further work is needed to increase conductivity to meet requirements of current IT-SOFCs.
Dielectric Properties in Co-Ti Doped CaSrM Hexaferrites iosrjce
The dependence of dielectric constant ' and dielectric loss tangent tanon frequency and
composition have been investigated at fixed temperatures for polycrystalline Ca0.5Sr0.5CoxTixFe12-2xO19 (where
0.0 ≤ x ≤ 0.8) hexaferrites samples prepared by ceramic method. The measurements reveal that the samples
under investigation have high values of ' reached to 106
at 1 KHz and 600K. The experimental results indicated
that ' and tandecrease as the frequency increases and temperature decreases. The studied samples showed
an abnormal dielectric loss (or relaxation peaks) which were shifted towards higher frequency as the
temperature increases. ' and tan increase as Co and Ti ions substitution increases up to x≤0.4, after that both
parameters decreases. The activation energy for dielectric relaxation, ED, was estimated for the samples. It is
shown that, ED, have low values (~0.08- 0.18 eV) and have inverse proportional with the dielectric constant '.
Influence of phase transformation on the work hardening characteristics of Pb...iosrjce
IOSR Journal of Mechanical and Civil Engineering (IOSR-JMCE) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of mechanical and civil engineering and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in mechanical and civil engineering. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
The document analyzes the materials used in various parts of a low-end hairdryer. The heating wire was found to be made of Kanthal alloy, which is commonly used for heating elements due to its resistance and conductivity. The back of the case was determined to be injection molded ABS plastic through testing of its properties, structure, and infrared spectroscopy. Other parts included PVC insulated wires, a bimetallic temperature switch made of copper and steel, and ceramic magnets containing strontium hexaferrite in the electric motor.
Thermal, microstructure and dielectric behavior of la modified bismuth titana...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
Annealing and Microstructural Characterization of Tin-Oxide Based Thick Film ...Anis Rahman
Abstract. The sheet resistance of tin oxide based thick-film resistors exhibits two regions of temperature dependence,
described by hopping (23°C-200°C) and diffusion mechanisms (200°C-350°C), respectively.
Annealing these samples causes the sheet resistance to increase in both regions. In the post-annealed samples,
the hopping conduction range is extended by 50°C (23°C-250°C) while the hopping parameter, To, is decreased by
more than 50%. The activation energy of diffusion (0.60 eV) is the same for both pre- and post annealed samples, but
the magnitude of resistance in the diffusion controlled region is increased significantly as a result of annealing. These
changes are explained in terms of a net decrease in the concentration of tin ions in the glass matrix. From a careful
microstructural study it was found that a conduction path composed of tin-oxide grains or their clusters in contact
with each other does not exist in the present system. HREM micrographs showed the presence of nanocrystalline
tin-oxide particles in the glass phase separating the tin-oxide grain clusters. Estimated average separation between
the nanocrystals in 4 nm, consistent with a variable-range hopping conduction via the dissolved tin ions in the glass
matrix.
Structure, microstructure and dielectric study of (ba0.6 sr0.4)(zr0.6ti0.4)o3...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.
Bruce Decker Journal of Thermal EngineeringBruce Decker
This document summarizes the results of experiments testing the thermoelectric properties of bismuth telluride filled silicone composite wires created via electrospinning. Bismuth telluride and silicone rubber were mixed and extruded into millimeter-sized wires. The electrical resistance of the composite wires was measured to be as high as 2.9*1010 ohms. Seebeck coefficient measurements also showed the composite material exhibited a high Seebeck effect due to the low thermal conductivity of the silicone rubber matrix. The flexibility of the composite material and enhancement of bismuth telluride's thermoelectric properties indicates potential for flexible alternative energy applications.
Dielectric Constant of nano- CCTO / Epoxy CompositeIOSR Journals
Nanocrystalline multiphase CaCu3Ti4O12 (CCTO) was prepared using Ca(NO3)2.4H2O, Cu(NO3)2.3H2O, TiO2 and C2H2O4.2H2O. The X-Ray differection and SEM analysed of the prepared CCTO powder sintered at 900oC and 950oC. A homogeneous ceramics-polymer nanocomposites consisting of CCTO particles as fillers and epoxy polymer as matrix have been prepared using a casting process. The nanocomposites exhibit enhanced dielectric constant and dielectric loss. Dielectric properties of CCTO ceramics were characterized in a broad frequency range (100 Hz-1 MHz) and at a temperature ranged from 25 oC to 150 oC. As a result of increasing the content of CCTO, the dielectric constant and dielectric loss of composites are increased. The increase of dielectric loss at high frequencies is due to the relaxation process in the polymer matrix.
Effect of Temperature and Nickel Concentration on the Electrical and Dielectr...IJERD Editor
In this paper the effect of temperature range of 298 K to 348 K and volume filler content ф on
electrical properties of polyethylene PE filled with nickel Ni powders has been investigated .The volume
electrical resistivity
V
of such composites decreases suddenly by several orders of magnitude at a critical
volume concentration (i.e. фc=14.27 Vol.%) ,whereas the dielectric constant and the A.C electrical
conductivity AC of such composites increase suddenly at a critical volume concentration (i.e. фc=14.27
Vol.%).For volume filler content lower than percolation threshold ф<фc> фc there is increase in the value of their
resistivity, and decrease in the value of their dielectric constant and the A.C electrical conductivity AC with
increasing temperature indicating metallic-conduction.
This document summarizes research on photovoltaic structures using thermally evaporated tin sulfide thin films. Key points:
- Tin sulfide films were deposited by thermal evaporation onto glass substrates in thicknesses ranging from 100-300nm.
- The films exhibited n-type conductivity at low thicknesses, transitioning to p-type at higher thicknesses. Bandgaps ranged from 2.1-1.7eV.
- CdS/SnS photovoltaic cells showed open circuit voltages up to 400mV, short circuit current densities up to 0.061mA/cm2, and conversion efficiencies up to 1.49% under 106mW/cm2 illumination.
This document provides an overview of polymers including definitions of key terms like plastics, elastomers, thermoplastics, and thermosetting plastics. Thermoplastics can be remelted and reformed, while thermosetting plastics set permanently once formed. Examples of properties, mechanical behaviors like creep and stress relaxation, optical properties including luminescence, and polymerization processes are also summarized. The document concludes with references for further reading on materials science topics.
10.1016-j.mssp.2015.01.037-Electrochemical investigation of graphene_nanoporo...Mahdi Robat Sarpoushi
This study investigated the effect of mixing graphene nanosheets and nanoporous carbon black on the surface morphology and electrochemical performance of electrodes prepared for supercapacitors. Electrodes containing 80% nanoporous carbon black, 10% graphene nanosheets, and 10% PTFE binder showed the highest specific capacitance of 10.22 F/g. The addition of nanoporous carbon black increased the proportion of outer charge stored on the electrode relative to the total charge stored, indicating higher current response and voltage reversal at the end potentials. Scanning electron microscopy images showed that adding nanoporous carbon black particles arranged the graphene nanosheets in different directions, increasing the specific surface area and changing diffusion characteristics to improve capacitance and reversibility
Graphene Transistors : Study for Analog and Digital applicationsvishal anand
This document summarizes a simulation study of graphene-based transistors for digital and analog applications. It provides an introduction to graphene basics and graphene nanoribbon field-effect transistor (GNR FET) structure. The document describes the software used for simulation and shows parametric simulation results. It calculates key digital parameters like ION/IOFF ratio and subthreshold swing and analog parameters like transconductance and drain resistance for the GNR FET. The modeling results are found to agree with experimental data. Challenges in GNR FETs include needing both n-type and p-type devices and relatively high voltage swings currently needed for switching.
Synthesis and analysis of electrical properties of Lead free Ba3Sr2LaTi3V7O30...inventy
This document summarizes research on the synthesis and analysis of electrical properties of a lead-free vanadate compound with the formula Ba3Sr2LaTi3V7O30. The compound was synthesized through solid-state sintering and characterized through X-ray diffraction and impedance spectroscopy. XRD analysis confirmed the formation of a single-phase orthorhombic structure. Impedance spectroscopy revealed the electrical response was mainly due to grain effects and identified two relaxation processes corresponding to grain boundaries and bulk effects. Conductivity increased with temperature, showing negative temperature coefficient behavior.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
The document discusses various thermal properties of materials including thermal expansion, heat capacity, thermal conductivity, and thermoelectric heating and cooling. It explains that thermal expansion occurs as the bond length and atomic positions shift with increasing temperature. Heat capacity represents the amount of energy required to produce a temperature rise. Thermal conductivity is the ability to transfer heat and depends on electron and phonon transport. Thermoelectric effects allow direct conversion between thermal and electrical energy.
Highly thermally conductive dielectric coatings produced by Plasma Electrolyt...Tamires Tah
The document describes research on producing highly thermally conductive dielectric coatings on aluminum substrates using plasma electrolytic oxidation (PEO). Key findings:
1. PEO was used to produce porous oxide coatings on aluminum in sodium silicate solutions. Coatings contained Al2O3, silicon, and had electrical resistivities suitable for heat sinks.
2. Thermal diffusivity and conductivity of coatings were significantly higher than aluminum, Al2O3, and AlN - up to 900% higher for some coatings.
3. The best performing coatings had thermal diffusivity of 1.38 x 10-4 m2/s and conductivity of 287 Wm-1K-
This document discusses waste heat recovery using thermoelectric generators. It begins by introducing the Seebeck effect which allows heat to be directly converted to electricity via a temperature gradient across conductors. The key factors for good thermoelectric materials - high Seebeck coefficient, electrical conductivity and low thermal conductivity - are discussed. Lead telluride is identified as a suitable high performance material for recovering waste heat between 200-600°C. A thermoelectric couple model is analyzed using ANSYS software, showing a voltage of 0.074806V, current of 19.083A and power of 1.4275W can be generated. The summary concludes the analysis demonstrates the potential of thermoelectric generation to recover low grade waste heat as
Influence of La3+ substitution on dielectric, ferroelectric and electrocalori...Mohammad Azam
Outline
Motivation
Dielectric properties of materials
Ferroelectric and Antiferroelectric
Electrocaloric Effect (EC)
Sample preparation method
Characterization techniques
Result and Discussion
Future Work
References
This document discusses thermoelectric materials and calculations using the Wien2K software. It describes the Seebeck effect and Peltier effect. It discusses using Wien2K to model materials like Mg2Si, calculate properties like density of states, band structure, and optimize volume. Modifying approximations, strain effects, and nanostructuring are discussed to increase thermoelectric figure of merit ZT by increasing power factor and decreasing thermal conductivity.
Reflectance and photoluminescence characterization of BexZn1Oleg Maksimov
This document summarizes research on the optical properties of BexZn1-xTe thin films grown by molecular beam epitaxy. Reflectance and photoluminescence measurements were performed on the epilayers as a function of BeTe content and temperature. An increase in emission line broadening was observed with higher BeTe content, which is attributed to alloy disorder. Temperature-dependent reflectance data showed a reduction in the variation of band gap energy with increasing BeTe content. This effect is proposed to be due to lattice hardening from BeTe decreasing the lattice contribution to the temperature dependence.
This document summarizes research on the electrical conductivity of Ba-Sr-Co-Fe cathode materials for solid oxide fuel cells (SOFCs). Single phase cubic Ba0.5Sr0.5Co1-xFexO3-δ compositions were synthesized via gel combustion and cation complexation routes. Electrical conductivity measurements showed that conductivity initially increased with temperature up to a maximum then decreased, attributed to oxygen loss from the lattice. Fe substitution had little effect on conductivity. While BSCF shows potential as an SOFC cathode, further work is needed to increase conductivity to meet requirements of current IT-SOFCs.
Dielectric Properties in Co-Ti Doped CaSrM Hexaferrites iosrjce
The dependence of dielectric constant ' and dielectric loss tangent tanon frequency and
composition have been investigated at fixed temperatures for polycrystalline Ca0.5Sr0.5CoxTixFe12-2xO19 (where
0.0 ≤ x ≤ 0.8) hexaferrites samples prepared by ceramic method. The measurements reveal that the samples
under investigation have high values of ' reached to 106
at 1 KHz and 600K. The experimental results indicated
that ' and tandecrease as the frequency increases and temperature decreases. The studied samples showed
an abnormal dielectric loss (or relaxation peaks) which were shifted towards higher frequency as the
temperature increases. ' and tan increase as Co and Ti ions substitution increases up to x≤0.4, after that both
parameters decreases. The activation energy for dielectric relaxation, ED, was estimated for the samples. It is
shown that, ED, have low values (~0.08- 0.18 eV) and have inverse proportional with the dielectric constant '.
Influence of phase transformation on the work hardening characteristics of Pb...iosrjce
IOSR Journal of Mechanical and Civil Engineering (IOSR-JMCE) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of mechanical and civil engineering and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in mechanical and civil engineering. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
The document analyzes the materials used in various parts of a low-end hairdryer. The heating wire was found to be made of Kanthal alloy, which is commonly used for heating elements due to its resistance and conductivity. The back of the case was determined to be injection molded ABS plastic through testing of its properties, structure, and infrared spectroscopy. Other parts included PVC insulated wires, a bimetallic temperature switch made of copper and steel, and ceramic magnets containing strontium hexaferrite in the electric motor.
Thermal, microstructure and dielectric behavior of la modified bismuth titana...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
Annealing and Microstructural Characterization of Tin-Oxide Based Thick Film ...Anis Rahman
Abstract. The sheet resistance of tin oxide based thick-film resistors exhibits two regions of temperature dependence,
described by hopping (23°C-200°C) and diffusion mechanisms (200°C-350°C), respectively.
Annealing these samples causes the sheet resistance to increase in both regions. In the post-annealed samples,
the hopping conduction range is extended by 50°C (23°C-250°C) while the hopping parameter, To, is decreased by
more than 50%. The activation energy of diffusion (0.60 eV) is the same for both pre- and post annealed samples, but
the magnitude of resistance in the diffusion controlled region is increased significantly as a result of annealing. These
changes are explained in terms of a net decrease in the concentration of tin ions in the glass matrix. From a careful
microstructural study it was found that a conduction path composed of tin-oxide grains or their clusters in contact
with each other does not exist in the present system. HREM micrographs showed the presence of nanocrystalline
tin-oxide particles in the glass phase separating the tin-oxide grain clusters. Estimated average separation between
the nanocrystals in 4 nm, consistent with a variable-range hopping conduction via the dissolved tin ions in the glass
matrix.
Structure, microstructure and dielectric study of (ba0.6 sr0.4)(zr0.6ti0.4)o3...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.
Bruce Decker Journal of Thermal EngineeringBruce Decker
This document summarizes the results of experiments testing the thermoelectric properties of bismuth telluride filled silicone composite wires created via electrospinning. Bismuth telluride and silicone rubber were mixed and extruded into millimeter-sized wires. The electrical resistance of the composite wires was measured to be as high as 2.9*1010 ohms. Seebeck coefficient measurements also showed the composite material exhibited a high Seebeck effect due to the low thermal conductivity of the silicone rubber matrix. The flexibility of the composite material and enhancement of bismuth telluride's thermoelectric properties indicates potential for flexible alternative energy applications.
Dielectric Constant of nano- CCTO / Epoxy CompositeIOSR Journals
Nanocrystalline multiphase CaCu3Ti4O12 (CCTO) was prepared using Ca(NO3)2.4H2O, Cu(NO3)2.3H2O, TiO2 and C2H2O4.2H2O. The X-Ray differection and SEM analysed of the prepared CCTO powder sintered at 900oC and 950oC. A homogeneous ceramics-polymer nanocomposites consisting of CCTO particles as fillers and epoxy polymer as matrix have been prepared using a casting process. The nanocomposites exhibit enhanced dielectric constant and dielectric loss. Dielectric properties of CCTO ceramics were characterized in a broad frequency range (100 Hz-1 MHz) and at a temperature ranged from 25 oC to 150 oC. As a result of increasing the content of CCTO, the dielectric constant and dielectric loss of composites are increased. The increase of dielectric loss at high frequencies is due to the relaxation process in the polymer matrix.
Effect of Temperature and Nickel Concentration on the Electrical and Dielectr...IJERD Editor
In this paper the effect of temperature range of 298 K to 348 K and volume filler content ф on
electrical properties of polyethylene PE filled with nickel Ni powders has been investigated .The volume
electrical resistivity
V
of such composites decreases suddenly by several orders of magnitude at a critical
volume concentration (i.e. фc=14.27 Vol.%) ,whereas the dielectric constant and the A.C electrical
conductivity AC of such composites increase suddenly at a critical volume concentration (i.e. фc=14.27
Vol.%).For volume filler content lower than percolation threshold ф<фc> фc there is increase in the value of their
resistivity, and decrease in the value of their dielectric constant and the A.C electrical conductivity AC with
increasing temperature indicating metallic-conduction.
This document summarizes research on photovoltaic structures using thermally evaporated tin sulfide thin films. Key points:
- Tin sulfide films were deposited by thermal evaporation onto glass substrates in thicknesses ranging from 100-300nm.
- The films exhibited n-type conductivity at low thicknesses, transitioning to p-type at higher thicknesses. Bandgaps ranged from 2.1-1.7eV.
- CdS/SnS photovoltaic cells showed open circuit voltages up to 400mV, short circuit current densities up to 0.061mA/cm2, and conversion efficiencies up to 1.49% under 106mW/cm2 illumination.
This document provides an overview of polymers including definitions of key terms like plastics, elastomers, thermoplastics, and thermosetting plastics. Thermoplastics can be remelted and reformed, while thermosetting plastics set permanently once formed. Examples of properties, mechanical behaviors like creep and stress relaxation, optical properties including luminescence, and polymerization processes are also summarized. The document concludes with references for further reading on materials science topics.
10.1016-j.mssp.2015.01.037-Electrochemical investigation of graphene_nanoporo...Mahdi Robat Sarpoushi
This study investigated the effect of mixing graphene nanosheets and nanoporous carbon black on the surface morphology and electrochemical performance of electrodes prepared for supercapacitors. Electrodes containing 80% nanoporous carbon black, 10% graphene nanosheets, and 10% PTFE binder showed the highest specific capacitance of 10.22 F/g. The addition of nanoporous carbon black increased the proportion of outer charge stored on the electrode relative to the total charge stored, indicating higher current response and voltage reversal at the end potentials. Scanning electron microscopy images showed that adding nanoporous carbon black particles arranged the graphene nanosheets in different directions, increasing the specific surface area and changing diffusion characteristics to improve capacitance and reversibility
Graphene Transistors : Study for Analog and Digital applicationsvishal anand
This document summarizes a simulation study of graphene-based transistors for digital and analog applications. It provides an introduction to graphene basics and graphene nanoribbon field-effect transistor (GNR FET) structure. The document describes the software used for simulation and shows parametric simulation results. It calculates key digital parameters like ION/IOFF ratio and subthreshold swing and analog parameters like transconductance and drain resistance for the GNR FET. The modeling results are found to agree with experimental data. Challenges in GNR FETs include needing both n-type and p-type devices and relatively high voltage swings currently needed for switching.
Synthesis and analysis of electrical properties of Lead free Ba3Sr2LaTi3V7O30...inventy
This document summarizes research on the synthesis and analysis of electrical properties of a lead-free vanadate compound with the formula Ba3Sr2LaTi3V7O30. The compound was synthesized through solid-state sintering and characterized through X-ray diffraction and impedance spectroscopy. XRD analysis confirmed the formation of a single-phase orthorhombic structure. Impedance spectroscopy revealed the electrical response was mainly due to grain effects and identified two relaxation processes corresponding to grain boundaries and bulk effects. Conductivity increased with temperature, showing negative temperature coefficient behavior.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
The document discusses various thermal properties of materials including thermal expansion, heat capacity, thermal conductivity, and thermoelectric heating and cooling. It explains that thermal expansion occurs as the bond length and atomic positions shift with increasing temperature. Heat capacity represents the amount of energy required to produce a temperature rise. Thermal conductivity is the ability to transfer heat and depends on electron and phonon transport. Thermoelectric effects allow direct conversion between thermal and electrical energy.
Highly thermally conductive dielectric coatings produced by Plasma Electrolyt...Tamires Tah
The document describes research on producing highly thermally conductive dielectric coatings on aluminum substrates using plasma electrolytic oxidation (PEO). Key findings:
1. PEO was used to produce porous oxide coatings on aluminum in sodium silicate solutions. Coatings contained Al2O3, silicon, and had electrical resistivities suitable for heat sinks.
2. Thermal diffusivity and conductivity of coatings were significantly higher than aluminum, Al2O3, and AlN - up to 900% higher for some coatings.
3. The best performing coatings had thermal diffusivity of 1.38 x 10-4 m2/s and conductivity of 287 Wm-1K-
This document discusses waste heat recovery using thermoelectric generators. It begins by introducing the Seebeck effect which allows heat to be directly converted to electricity via a temperature gradient across conductors. The key factors for good thermoelectric materials - high Seebeck coefficient, electrical conductivity and low thermal conductivity - are discussed. Lead telluride is identified as a suitable high performance material for recovering waste heat between 200-600°C. A thermoelectric couple model is analyzed using ANSYS software, showing a voltage of 0.074806V, current of 19.083A and power of 1.4275W can be generated. The summary concludes the analysis demonstrates the potential of thermoelectric generation to recover low grade waste heat as
Influence of La3+ substitution on dielectric, ferroelectric and electrocalori...Mohammad Azam
Outline
Motivation
Dielectric properties of materials
Ferroelectric and Antiferroelectric
Electrocaloric Effect (EC)
Sample preparation method
Characterization techniques
Result and Discussion
Future Work
References
This document discusses thermoelectric materials and calculations using the Wien2K software. It describes the Seebeck effect and Peltier effect. It discusses using Wien2K to model materials like Mg2Si, calculate properties like density of states, band structure, and optimize volume. Modifying approximations, strain effects, and nanostructuring are discussed to increase thermoelectric figure of merit ZT by increasing power factor and decreasing thermal conductivity.
Thermoelectric Power Studies of Ni-Co Nano Ferrites Synthesized By Citrate-Ge...IOSR Journals
This document reports on a study of the thermoelectric power of nickel-cobalt nanoferrites with the chemical formula Ni1-xCoxFe2O4 (where x = 0, 0.2, 0.4, 0.6, 0.8, 1.0) synthesized using the citrate-gel auto combustion method. X-ray diffraction analysis confirmed the formation of a single cubic spinel phase without impurities. Lattice parameters increased with increasing cobalt content due to the larger ionic radius of Co2+ ions compared to Ni2+ ions. Seebeck coefficient measurements from 320K to above the Curie temperature showed that the materials behaved as n-type semiconductors and the
Effect of sintering time on the particle size and dielectric properties of La...ijceronline
International Journal of Computational Engineering Research (IJCER) is dedicated to protecting personal information and will make every reasonable effort to handle collected information appropriately. All information collected, as well as related requests, will be handled as carefully and efficiently as possible in accordance with IJCER standards for integrity and objectivity.
A study of lattice parameters and dielectric properties against temperature a...iosrjce
IOSR Journal of Applied Physics (IOSR-JAP) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of physics and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in applied physics. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Study of Boron Based Superconductivity and Effect of High Temperature Cuprate...IOSR Journals
This paper illustrates the main normal and Boron superconducting state temperature properties of magnesium diboride, a substance known since early 1950's, but lately graded to be superconductive at a remarkably high critical temperature Tc=40K for a binary synthesis. What makes MgB2 so special? Its high Tc, simple crystal construction, large coherence lengths, high serious current densities and fields, lucidity of surface boundaries to current promises that MgB2 will be a good material for both large scale applications and electronic devices. Throughout the last seven month, MgB2 has been fabricated in various shape, bulk, single crystals, thin films, ribbons and wires. The largest critical current densities >10MA/cm2 and critical fields 40T are achieved for thin films. The anisotropy attribution inferred from upper critical field measurements is still to be resolved, a wide range of values being reported, γ = 1.2 ÷ 9. Also there is no consensus about the existence of a single anisotropic or double energy cavity. One central issue is whether or not MgB2 represents a new class of superconductors, being the tip of an iceberg that waits to be discovered. Until now MgB2 holds the record of the highest Tc among simple binary synthesis. However, the discovery of superconductivity in MgB2 revived the interest in non-oxides and initiated a search for superconductivity in related materials, several synthesis being already announced to become superconductive: TaB2, BeB2.75, C-S composites, and the elemental B under pressure.
the effect of nickel incorporation on some physical properties of epoxy resinINFOGAIN PUBLICATION
The J-E characteristics of samples of epoxy resins mixed with nickel powder in different concentrations have been tested and a log-log straight line behaviour in both the low- and high field regions is observed. Ni-concentration has significant influence on the calculated constants of the J-E relationship. The d.c. electrical resistivity (ρ) of the samples are measured from the room temperature up to about 400 K. The variation of ρ with T obeys the exponential relation of ordinary dielectrics in three temperature regions. The parameters characterizing the ρ -T dependence change considerably with Ni-concentration. Due to the existence of nickel in different concentration a "true" compensation effect is observed with three characteristic compensation temperatures. The mechanical hardness of the samples was investigated as a function of Ni-concentration.
An understanding of the electronic bipolar resistance switching behavior in C...IJRES Journal
In this study, TiO2 films and devices were prepared by sol-gel method. The bipolar resistive switching
phenomena was observed in the Cu/TiO2/ITO device. The conduction mechanism of devices were analyzed. It was
found that the conduction mechanism is dominated by space charge limited current in high resistance state, and
Schottky emission in low resistance state.
Study of Microstructural, Electrical and Dielectric Properties of La0.9Pb0.1M...Scientific Review SR
The present work studies the microstructural and electrical properties of La0.9Pb0.1MnO3 and La0.8Y0.1Pb0.1MnO3 ceramics synthesized by solid-state route method. Microstructure and elemental analysis of both samples were carried out by field emission scanning electron microscope (FESEM) and energy dispersive spectroscopy (EDS) method, respectively. Phase analysis by X-ray diffraction (XRD) indicated formation of single phase distorted structure. The XRD data were further analyzed by Rietveld refinement technique. Raman analysis reveals that Y atom substitutes La site into the LPMO with shifting of phonon modes. The temperature variation of resistivity of undoped and Y-doped La0.9Pb0.1MnO3 samples have been investigated. The electrical resistivity as a function of temperature showed that all samples undergo an metal-insulator (M-I) transition having a peak at transition temperature TMI. Y-doping increases the resistivity and the metal-insulator transition temperature (TMI) shifts to lower temperature. The temperature-dependent resistivity for temperatures less than metal-insulator transition is explained in terms the quadratic temperature dependence and for T > TMI, thermally activated conduction (TAC) is appropriate. Variation of frequency dispersion in permittivity and loss pattern due to La-site substitution in LPMO was observed in the dielectric response curve.
Study the effect of Mn2+ ions on the ac electrical properties of some iron do...IJRES Journal
Oxide glasses doped with transition metal ions are of high interest because of their variant applications in both science and technology fields. However, the normal melt quench method have used to prepared some iron doped phosphate glasses according the following molecular formula: (65-x) mol% P2O5 - 20 mol% Na2O - 15 mol% Fe2O3 - x mol% MnO, Where x= 0, 5,10, 20, 25. The room temperature Mössbauer Effect ME Spectra used to characterized the glassy state homogeneity of these glasses. ME spectra show, for all glasses, no magnetic field participate which mean good glassy state formation. The ac electrical transport properties were also measured, as function of temperature up to 500k. It was found that the ac conductivity increased with the gradual increase of Mn2+ cations, while the electrical activation energy decreased.
Fabrication and electrical characteristic of quaternary ultrathin hf tiero th...Alexander Decker
This document describes the fabrication and electrical characterization of quaternary ultrathin HfTiErO thin films grown by RF sputtering for MOS devices. HfTiErO thin films with different Ti and Er contents were deposited on silicon substrates. The films were annealed at 500°C and 700°C. Atomic force microscopy showed the surface roughness decreased with annealing. X-ray photoelectron spectroscopy analysis showed the chemical compositions. MOS capacitors were fabricated and capacitance-voltage measurements showed the annealed films at 500°C had improved electrical properties like higher dielectric constant. The HfTiErO film with composition HfTi6Er4O annealed at 500°C achieved the best electrical performance of the
Compatibility Analyses of Bicuvox.10 as a Cathode in Yttria-stabilized Zircon...Marcelo Tramontin
The document examines the compatibility of copper-substituted bismuth vanadate (BICUVOX.10) as a cathode material in yttria-stabilized zirconia (YSZ) electrolytes for solid oxide fuel cells. When BICUVOX.10 interacts with YSZ, secondary phases form including yttrium vanadate (YVO4) and monoclinic zirconia. This is due to a reaction between the YO1.5 stabilizer cation in ZrO2 and VO2.5 from BICUVOX.10, depleting yttria from the zirconia lattice and destabilizing the tetragonal and cubic zirconia
This document summarizes research on designing annular ring frequency selective surfaces (FSS) using different dielectric substrate materials. The research aims to achieve dual-band frequency response with controllable shift in resonance frequencies. FSS designs with annular ring elements are simulated using substrates like Teflon, Mica and FR4. Simulation results show dual transmission bands in C-band and X-band, with the frequencies shifting based on the dielectric constant of the material. Teflon provides the highest resonance frequencies while Mica and FR4 shift the frequencies down as their dielectric constants increase. The study demonstrates annular ring FSS can produce dual-band response with substrate material choice enabling predictable frequency shifts.
The large amount of waste heat produced by power plants and automobile engines can be converted into electricity due to the thermoelectric effect, a physics effect that converts temperature differences into electrical energy. As long as you can maintain temperature difference, it will keep on generating electricity, for that one needs a material with low thermal conductivity. in the poster above, a method to reduce thermal conductivity is proposed which in turn increased the efficiency.
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
The papers for publication in The International Journal of Engineering& Science are selected through rigorous peer reviews to ensure originality, timeliness, relevance, and readability.
ELECTRICAL PROPERTIES OF NI0.4MG0.6FE2O4 SYNTHESIZED BY CONVENTIONAL SOLID-ST...IAEME Publication
Ni0.4Mg0.6Fe2O4 samples are prepared by conventional double sintering approach and sintered at 1300oC/ 2 h. These ferrites are characterized using X-ray diffractometer. The diffraction study reveals that the present compound shows perfect single phase cubic spinel structure. In addition, the behavior of distinct electrical properties such as dielectric constant (ε'), dielectric loss (ε") and ac-conductivity (σac) as a function frequency as well as temperature is analyzed using the LCR controller
Heat treatment of BFO film deposited on Si (111): Spectroscopic studyiosrjce
IOSR Journal of Applied Physics (IOSR-JAP) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of physics and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in applied physics. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
- Nanoparticles NiFe2-xTbxO4 (x=0.00, 0.04, 0.08,
0.12) ferrite was prepared by solgel combution method. The
samples were characterized with X-ray diffraction and TEM
measurements. The effect of Tb3+ cations substitution on
structure of prepared nanoparticles was investigated. From the
analysis, the system was found to be inverse spinel cubic
structure. The lattice parameter (a) changes increases with Tb
doping content. Room temperature DC electrical resistivity
decreases. Dielectric properties have been studied in the
frequency range of 1 kHz to 5 MHz. Permittivity and tangent
loss (tanδ) decreases with the substitution of Tb3+ in parent
crystal structure.
The impact of surface hydrogenation on the thermionic electron emission from ...PROMETHEUS Energy
In this work, thermionic electron emission (TEE) from hot
filament chemical vapour deposition polycrystalline diamond
films deposited on p-type silicon substrates was recorded in
the 25–650 8C temperature range. The studied surfaces were
as deposited, as well as hydrogenated by atomic hydrogen
under ultra-high vacuum conditions. The impact of substrate
temperature during hydrogenation, TH, on TEE was studied.
For TH ¼ 25 8C the TEE was found to display a broad maximum
at substrate temperature around 300 8C followed by an
exponential increase. Annealing at 700 8C results in irreversible
changes in surface conditioning, and drastic reduction of TEE
yield at low temperatures. For samples that underwent
hydrogenation at TH ¼ 300 and 500 8C, the TEE yield is
significant at higher temperatures only. The TEE from these
samples is stable also after 700 8C annealing treatment. We
associate these effects with irreversible thermal induced
physicochemical changes of the hydrogen bonding configuration
adsorbed on the polycrystalline diamond surface resulting
in changes in its surface electronic structure which occur upon
annealing to 300 8C.
Similar to Synthesis and Dielectric Characterization of Barium Substituted Strontium Bismuth Niobate Layered Perovskite Oxides (20)
New Thermodynamics: A Superior Fit Revised Kinetic Theoryijrap
The accepted kinetic theory forms a basis for modern thermodynamics and is mathematically based upon equipartition and degrees of freedom. It remains plagued with the necessity of numerous degrees of freedom exceptions for it to explain both empirically determined heat capacities and adiabatic indexes. Furthermore, assuming kT/2 per degree of freedom is to accept that a gas molecule possesses a specified energy without providing any clarity concerning that energy’s origins. Energy without an origin contravenes the first law of thermodynamics. This author’s previously published superior fit kinetic theory will be clarified and elaborated upon. This includes showing that this revised kinetic theory is a superior fit to both known heat capacities and adiabatic indexes. Not only is it a superior fit that does not rely upon any exceptions, this author’s kinetic theory also provides insight into the actual sources of a gas molecule’s energy. Furthermore, clarity concerning the difference between isometric (isochoric) and isobaric heat capacities in terms of sensible work will be discussed, along withits likely empirical verification.
On the Unification of Physic and the Elimination of Unbound Quantitiesijrap
This paper supports Descartes' idea of a constant quantity of motion, modernized by Leibniz. Unlike Leibniz, the paper emphasizes that the idea is not realized by forms of energy, but by energy itself. It remains constant regardless of the form, type, or speed of motion, even that of light. Through force, energy is only transformed. Here it is proved that force is its derivative. It exists even at rest, representing the object's minimal energy state. With speed, we achieve its multiplication up to the maximum energy state, from which a maximum force is derived from the object. From this point, corresponding to Planck's Length, we find the value of the force wherever we want. Achieving this removes the differences between various natural forces. The new idea eliminates infinite magnitudes. The process allows the laws to transition from simple to complex forms and vice versa, through differentiation-integration. For this paper, this means achieving the Unification Theory.
Gravity Also Redshifts Light – the Missing Phenomenon That Could Resolve Most...ijrap
In this paper I discover that gravity also redshifts light like the velocity of its source does. When light travels towards a supermassive object, its waves (or photons) undergo continuous stretching, thereby shifting towards lower frequencies. Gravity redshifts light irrespective of whether its source is in motion or static with respect to its observer. An equation is derived for gravitational redshift, and a formula for combined redshift is presented by considering both the velocity, and gravity redshifts. Also explained is how frequencies of electromagnetic spectrum continuously downgrade as a light beam of mix frequencies passes towards a black hole. Further, a clear methodology is provided to figure out whether expansion of the universe is accelerating or decelerating, or alternatively, the universe is contracting.
In this paper I present a new theory that explains as to when and how dark energy is created as mass is destroyed. The theory extends Einstein’s mass energy equation to a more generic form in order to make it work even in high gravity conditions. It also explains why dark energy is created. Further, it is proved Einstein’s mass energy equation holds good only when the destroyed mass has no supermassive object in its close vicinity. The relationship between dark energy and dark matter is unveiled. An extended mathematical form of Einstein’s mass energy equation is derived, based on which the conditions leading to dark energy creation are explained. Three new physical parameters called dark energy discriminant, dark energy radius and dark energy boundary are introduced to facilitate easy understanding of the theory. It is explained in detail that an extremely superdense object has two dark energy boundaries, outer and inner. Mass destroyed only between these two boundaries creates dark energy. Dark energy space, the space between the two aforementioned boundaries, shrouds visible matter in obscurity from optical and electromagnetic telescopes. This theory identifies Gargantuan as a superdense black hole currently creating fresh dark energy, which could be the subject of interest for the astronomical research community having access to sophisticated telescopes, and working on dark energy. It also upholds dark energy and denies the existence of dark matter. Dark matter is nothing but the well-known visible matter positioned in dark energy space. An important relationship is derived between a photon’s frequency and its distance from a black hole to demonstrate the effect of gravity on light. Another important fact revealed by this theory is gravity stretches out light, thereby causing redshift, which is unaccounted in the computation of velocities of outer galaxies. Whether the universe is undergoing accelerated or decelerated expansion, or accelerated contraction can precisely be determined only after accounting for the redshift caused by gravity
International Journal on Soft Computing, Artificial Intelligence and Applicat...ijrap
International Journal on Soft Computing, Artificial Intelligence and Applications (IJSCAI)
is an open access peer-reviewed journal that provides an excellent international forum for sharing
knowledge and results in theory, methodology and applications of Artificial Intelligence, Soft
Computing. The Journal looks for significant contributions to all major fields of the Artificial
Intelligence, Soft Computing in theoretical and practical aspects. The aim of the Journal is to
provide a platform to the researchers and practitioners from both academia as well as industry to
meet and share cutting-edge development in the field.
Authors are solicited to contribute to the journal by submitting articles that illustrate research
results, projects, surveying works and industrial experiences that describe significant advances in
the areas of Database management systems.
SOME THEORETICAL ASPECTS OF HYDROGEN DIFFUSION IN BCC METALS AT LOW TEMPERATURESijrap
Purpose of the work is to discuss some theoretical aspects of the diffusion of hydrogen atoms in the crystal
lattice of BCC metals at low temperatures using the methods of statistical thermodynamics. The values of
the statistical model calculations of H diffusion coefficients in α-Fe, V, Ta, Nb, K are in good agreement
with the experimental data. The statistical model can also explain deviations from the Arrhenius equation
at temperatures 300-100 K in α-Fe, V, Nb and K. It was suggested that thermally activated fast tunnelling
transition of hydrogen atoms through the potential barrier at a temperature below 300 K provides an
almost free movement of H atoms in the α-Fe and V lattice at these temperatures. The results show that
quantum-statistical effects play a decisive role in the H diffusion in BCC metals at low temperatures. Using
the statistical model allows for the prediction of the diffusion coefficient for H in BCC metals at low
temperatures, where it’s necessary to consider quantum effects.
MASSIVE PHOTON HYPOTHESIS OPENS DOORS TO NEW FIELDS OF RESEARCHijrap
1) A massive photon hypothesis is proposed, where the photon mass is directly calculated from kinetic gas theory to be 1.25605 x 10-39 kg.
2) This photon mass explains various experiments like light deflection near the Sun and the gravitational redshift.
3) The photon gas is found to behave as a perfect blackbody and ideal gas, with photons having 6 degrees of freedom.
4) The thermal de Broglie wavelength of this photon gas is calculated to be 1.75967 x 10-3 m, matching the wavelength of the cosmic microwave background radiation.
5) This links the CMB radiation to being continuously generated by the photon gas permeating space, rather than being a relic of
PHENOMENOLOGICAL METHOD REGARDING A THIRD THEORY OF PHYSICS “THE EVENT:THE TH...ijrap
The quest for a third theory uniting macro-cosmos (relativity) and micro-cosmos (quantum mechanics) has coexisted with the denial of feminine/subjective polarity to masculine/objective. The dismissal of electromagnetism as the tension of opposites in quest of inner/outer unity is sourced in the denial of the feminine qualia -- the negative force field attributed to dark energy/dark matter. However, a conversion philosophy sourced in the hieros gamos and signified by the Mobius strip has formulated an integral consciousness methodology producing quantum objects by means of embracing the shadow haunting contemporary physics. This Self-reflecting process integrating subject/object comprises an ontology of kairos as the “quantum leap.” An interdisciplinary quest to create a phenomenological narrative is disclosed via a holistic apparatus of hermeneutics manifesting image/text of a contemporary grail journey. Reflected in this Third space is the sacred reality of autonomous number unifying polarities of feminine/subjective (quality) and objective/masculine (quantity) as new measurement apparatus for the quantum wave collapse.
3rd International Conference on Integrating Technology in Education (ITE 2022)ijrap
3rd International Conference on Integrating Technology in Education (ITE 2022) This forum also aims to provide a platform for exchanging ideas in new emerging trends that needs more focus and exposure and will attempt to publish proposals that strengthen our goals.
A SPECIAL RELATIONSHIP BETWEEN MATTER, ENERGY, INFORMATION, AND CONSCIOUSNESSijrap
This paper discusses the advantages of describing the universe, or nature, in terms of information and consciousness. Some problems encountered by theoretical physicists in the quest for the theory of everything stem from the limitations of trying to understand everything in terms of matter and energy only. However, if everything, including matter, energy, life, and mental processes, is described in terms of information and consciousness, much progress can be made in the search for the ultimate theory of the universe. As brilliant and successful as physics and chemistry have been over the last two centuries, it is important that nature is not viewed solely in terms of matter and energy. Two additional components are needed to unlock her secrets. While extensive writing exists that describes the connection between matter and energy and their physical basis, little work has been done to learn the special relationship between matter, energy, information, and consciousness.
This paper discusses the advantages of describing the universe, or nature, in terms of information and consciousness. Some problems encountered by theoretical physicists in the quest for the theory of everything stem from the limitations of trying to understand everything in terms of matter and energy only. However, if everything, including matter, energy, life, and mental processes, is described in terms of information and consciousness, much progress can be made in the search for the ultimate theory of the universe. As brilliant and successful as physics and chemistry have been over the last two centuries, it is important that nature is not viewed solely in terms of matter and energy. Two additional components are needed to unlock her secrets. While extensive writing exists that describes the connection between matter and energy and their physical basis, little work has been done to learn the special relationship between matter, energy, information, and
consciousness.
THE CONCEPT OF SPACE AND TIME: AN AFRICAN PERSPECTIVEijrap
Understanding the concept of space and time is critical, essential, and fundamental in searching for theall-encompassing theory or the theory of everything (ToE). Some physicists argue that time exists, whileothers posit that time is only a social or mental construct. The author presents an African thought systemon space and time conception, focusing on the African (Bantu) view of space and time. The author arguesthat before the advent of the Western linear view of space and time, Africans had their own visionregarding these two concepts. Their conception of time appears to be holistic, highly philosophical, non-linear, and thought-provoking. The author hopes that exploring these two concepts from an African perspective will provide a new and more in-depth insight into reality's nature. A scientific investigation of space and time from an African-centered perspective is a worthy and necessary endeavor in the quest forthe ToE
Learning to Pronounce as Measuring Cross Lingual Joint Orthography Phonology ...ijrap
Machine learning models allow us to compare languages by showing how hard a task in each language might be to learn and perform well on. Following this line of investigation, we explore what makes a language “hard to pronounce” by modelling the task of grapheme-to-phoneme (g2p) transliteration. By training a character-level transformer model on this task across 22 languages and measuring the model’s proficiency against its grapheme and phoneme inventories, we show that certain characteristics emerge that separate easier and harder languages with respect to learning to pronounce. Namely the complexity of a language's pronunciation from its orthography is due to the expressive or simplicity of its grapheme-to phoneme mapping. Further discussion illustrates how future studies should consider relative data sparsity per language to design fairer cross-lingual comparison tasks.
THE CONCEPT OF SPACE AND TIME: AN AFRICAN PERSPECTIVEijrap
Understanding the concept of space and time is critical, essential, and fundamental in searching for the all-encompassing theory or the theory of everything (ToE). Some physicists argue that time exists, while others posit that time is only a social or mental construct. The author presents an African thought system on space and time conception, focusing on the African (Bantu) view of space and time. The author argues
that before the advent of the Western linear view of space and time, Africans had their own vision
regarding these two concepts. Their conception of time appears to be holistic, highly philosophical, nonlinear, and thought-provoking. The author hopes that exploring these two concepts from an African
perspective will provide a new and more in-depth insight into reality's nature. A scientific investigation of space and time from an African-centered perspective is a worthy and necessary endeavor in the quest for the ToE.
International Journal of Recent advances in Physics (IJRAP)ijrap
International Journal of Recent advances in Physics (IJRAP) is a peer-reviewed, open access journal, addresses the impacts and challenges of Physics. The journal documents practical and theoretical results which make a fundamental contribution for the development of Physics.
The Concept of Space and Time: An African Perspectiveijrap
Understanding the concept of space and time is critical, essential, and fundamental in searching for the all-encompassing theory or the theory of everything (ToE). Some physicists argue that time exists, while others posit that time is only a social or mental construct. The author presents an African thought system on space and time conception, focusing on the African (Bantu) view of space and time. The author argues that before the advent of the Western linear view of space and time, Africans had their own vision regarding these two concepts. Their conception of time appears to be holistic, highly philosophical, nonlinear, and thought-provoking. The author hopes that exploring these two concepts from an African perspective will provide a new and more in-depth insight into reality's nature. A scientific investigation of space and time from an African-centered perspective is a worthy and necessary endeavor in the quest for the ToE.
The majority of physicists take it for granted that the universe is made up of matter. In turn, matter is composed of atoms; atoms are made up of particles such as electrons, protons, neutrons, etc. Also, protons
and neutrons are composed of quarks, etc. Furthermore, that everything in nature is governed by the known laws of physics and chemistry. The author only partially shares this view. He argues that many phenomena in the universe may depend on rules or factors as yet incorporated by the physical sciences.
The last few years have led him to reflect on the many unsolved physics problems, such as the quest for the theory of everything (ToE), the arrow of time, the interpretation of quantum mechanics, the fine-tuned
universe, etc. to mention just a few. The author posits that a field carries information, performs various mathematical and computational operations, and behaves as an intelligent entity embedded with consciousness.
Call For Papers - International Journal of Recent advances in Physics (IJRAP)ijrap
International Journal of Recent advances in Physics (IJRAP) is a peer-reviewed, open access journal, addresses the impacts and challenges of Physics. The journal documents practical and theoretical results which make a fundamental contribution for the development of Physics.
Call For Papers - International Journal of Recent advances in Physics (IJRAP)ijrap
The International Journal of Recent Advances in Physics (IJRAP) is a peer-reviewed open access journal that addresses impacts and challenges in the field of physics. It covers theoretical and practical results across many areas of physics including advanced functional materials, applied optics, condensed matter physics, nuclear physics, quantum physics, and more. Authors are invited to submit papers by email before October 30, 2021. Notifications of acceptance will be provided by November 25, 2021.
Call For Papers - International Journal of Recent advances in Physics (IJRAP)ijrap
International Journal of Recent advances in Physics (IJRAP) is a peer-reviewed, open access journal, addresses the impacts and challenges of Physics. The journal documents practical and theoretical results which make a fundamental contribution for the development of Physics.
Describing and Interpreting an Immersive Learning Case with the Immersion Cub...Leonel Morgado
Current descriptions of immersive learning cases are often difficult or impossible to compare. This is due to a myriad of different options on what details to include, which aspects are relevant, and on the descriptive approaches employed. Also, these aspects often combine very specific details with more general guidelines or indicate intents and rationales without clarifying their implementation. In this paper we provide a method to describe immersive learning cases that is structured to enable comparisons, yet flexible enough to allow researchers and practitioners to decide which aspects to include. This method leverages a taxonomy that classifies educational aspects at three levels (uses, practices, and strategies) and then utilizes two frameworks, the Immersive Learning Brain and the Immersion Cube, to enable a structured description and interpretation of immersive learning cases. The method is then demonstrated on a published immersive learning case on training for wind turbine maintenance using virtual reality. Applying the method results in a structured artifact, the Immersive Learning Case Sheet, that tags the case with its proximal uses, practices, and strategies, and refines the free text case description to ensure that matching details are included. This contribution is thus a case description method in support of future comparative research of immersive learning cases. We then discuss how the resulting description and interpretation can be leveraged to change immersion learning cases, by enriching them (considering low-effort changes or additions) or innovating (exploring more challenging avenues of transformation). The method holds significant promise to support better-grounded research in immersive learning.
EWOCS-I: The catalog of X-ray sources in Westerlund 1 from the Extended Weste...Sérgio Sacani
Context. With a mass exceeding several 104 M⊙ and a rich and dense population of massive stars, supermassive young star clusters
represent the most massive star-forming environment that is dominated by the feedback from massive stars and gravitational interactions
among stars.
Aims. In this paper we present the Extended Westerlund 1 and 2 Open Clusters Survey (EWOCS) project, which aims to investigate
the influence of the starburst environment on the formation of stars and planets, and on the evolution of both low and high mass stars.
The primary targets of this project are Westerlund 1 and 2, the closest supermassive star clusters to the Sun.
Methods. The project is based primarily on recent observations conducted with the Chandra and JWST observatories. Specifically,
the Chandra survey of Westerlund 1 consists of 36 new ACIS-I observations, nearly co-pointed, for a total exposure time of 1 Msec.
Additionally, we included 8 archival Chandra/ACIS-S observations. This paper presents the resulting catalog of X-ray sources within
and around Westerlund 1. Sources were detected by combining various existing methods, and photon extraction and source validation
were carried out using the ACIS-Extract software.
Results. The EWOCS X-ray catalog comprises 5963 validated sources out of the 9420 initially provided to ACIS-Extract, reaching a
photon flux threshold of approximately 2 × 10−8 photons cm−2
s
−1
. The X-ray sources exhibit a highly concentrated spatial distribution,
with 1075 sources located within the central 1 arcmin. We have successfully detected X-ray emissions from 126 out of the 166 known
massive stars of the cluster, and we have collected over 71 000 photons from the magnetar CXO J164710.20-455217.
The cost of acquiring information by natural selectionCarl Bergstrom
This is a short talk that I gave at the Banff International Research Station workshop on Modeling and Theory in Population Biology. The idea is to try to understand how the burden of natural selection relates to the amount of information that selection puts into the genome.
It's based on the first part of this research paper:
The cost of information acquisition by natural selection
Ryan Seamus McGee, Olivia Kosterlitz, Artem Kaznatcheev, Benjamin Kerr, Carl T. Bergstrom
bioRxiv 2022.07.02.498577; doi: https://doi.org/10.1101/2022.07.02.498577
Mending Clothing to Support Sustainable Fashion_CIMaR 2024.pdfSelcen Ozturkcan
Ozturkcan, S., Berndt, A., & Angelakis, A. (2024). Mending clothing to support sustainable fashion. Presented at the 31st Annual Conference by the Consortium for International Marketing Research (CIMaR), 10-13 Jun 2024, University of Gävle, Sweden.
Current Ms word generated power point presentation covers major details about the micronuclei test. It's significance and assays to conduct it. It is used to detect the micronuclei formation inside the cells of nearly every multicellular organism. It's formation takes place during chromosomal sepration at metaphase.
Authoring a personal GPT for your research and practice: How we created the Q...Leonel Morgado
Thematic analysis in qualitative research is a time-consuming and systematic task, typically done using teams. Team members must ground their activities on common understandings of the major concepts underlying the thematic analysis, and define criteria for its development. However, conceptual misunderstandings, equivocations, and lack of adherence to criteria are challenges to the quality and speed of this process. Given the distributed and uncertain nature of this process, we wondered if the tasks in thematic analysis could be supported by readily available artificial intelligence chatbots. Our early efforts point to potential benefits: not just saving time in the coding process but better adherence to criteria and grounding, by increasing triangulation between humans and artificial intelligence. This tutorial will provide a description and demonstration of the process we followed, as two academic researchers, to develop a custom ChatGPT to assist with qualitative coding in the thematic data analysis process of immersive learning accounts in a survey of the academic literature: QUAL-E Immersive Learning Thematic Analysis Helper. In the hands-on time, participants will try out QUAL-E and develop their ideas for their own qualitative coding ChatGPT. Participants that have the paid ChatGPT Plus subscription can create a draft of their assistants. The organizers will provide course materials and slide deck that participants will be able to utilize to continue development of their custom GPT. The paid subscription to ChatGPT Plus is not required to participate in this workshop, just for trying out personal GPTs during it.
When I was asked to give a companion lecture in support of ‘The Philosophy of Science’ (https://shorturl.at/4pUXz) I decided not to walk through the detail of the many methodologies in order of use. Instead, I chose to employ a long standing, and ongoing, scientific development as an exemplar. And so, I chose the ever evolving story of Thermodynamics as a scientific investigation at its best.
Conducted over a period of >200 years, Thermodynamics R&D, and application, benefitted from the highest levels of professionalism, collaboration, and technical thoroughness. New layers of application, methodology, and practice were made possible by the progressive advance of technology. In turn, this has seen measurement and modelling accuracy continually improved at a micro and macro level.
Perhaps most importantly, Thermodynamics rapidly became a primary tool in the advance of applied science/engineering/technology, spanning micro-tech, to aerospace and cosmology. I can think of no better a story to illustrate the breadth of scientific methodologies and applications at their best.
(June 12, 2024) Webinar: Development of PET theranostics targeting the molecu...Scintica Instrumentation
Targeting Hsp90 and its pathogen Orthologs with Tethered Inhibitors as a Diagnostic and Therapeutic Strategy for cancer and infectious diseases with Dr. Timothy Haystead.
The debris of the ‘last major merger’ is dynamically youngSérgio Sacani
The Milky Way’s (MW) inner stellar halo contains an [Fe/H]-rich component with highly eccentric orbits, often referred to as the
‘last major merger.’ Hypotheses for the origin of this component include Gaia-Sausage/Enceladus (GSE), where the progenitor
collided with the MW proto-disc 8–11 Gyr ago, and the Virgo Radial Merger (VRM), where the progenitor collided with the
MW disc within the last 3 Gyr. These two scenarios make different predictions about observable structure in local phase space,
because the morphology of debris depends on how long it has had to phase mix. The recently identified phase-space folds in Gaia
DR3 have positive caustic velocities, making them fundamentally different than the phase-mixed chevrons found in simulations
at late times. Roughly 20 per cent of the stars in the prograde local stellar halo are associated with the observed caustics. Based
on a simple phase-mixing model, the observed number of caustics are consistent with a merger that occurred 1–2 Gyr ago.
We also compare the observed phase-space distribution to FIRE-2 Latte simulations of GSE-like mergers, using a quantitative
measurement of phase mixing (2D causticality). The observed local phase-space distribution best matches the simulated data
1–2 Gyr after collision, and certainly not later than 3 Gyr. This is further evidence that the progenitor of the ‘last major merger’
did not collide with the MW proto-disc at early times, as is thought for the GSE, but instead collided with the MW disc within
the last few Gyr, consistent with the body of work surrounding the VRM.
Synthesis and Dielectric Characterization of Barium Substituted Strontium Bismuth Niobate Layered Perovskite Oxides
1. International Journal of Recent advances in Physics (IJRAP) Vol.2, No.4, November 2013
35
SYNTHESIS AND DIELECTRIC
CHARACTERIZATION OF BARIUM
SUBSTITUTED STRONTIUM BISMUTH
NIOBATE LAYERED PEROVSKITE OXIDES
H. S. Tewari* and Anupam Pati
Department of Pure and Applied Physics,
Guru Ghasidas Vishwavidyalaya, Bilaspur – 495009 (C.G.), India
ABSTRACT
The strontium bismuth niobate, SrBi2Nb2O9 (SBN) is a bismuth layered perovskite oxide
compound with potentially useful ferroelectric properties which offer several advantages such as fatigue
free, lead free, low operating voltages, relatively high Curie temperature; and most importantly, their
ferroelectric properties are independent of film thickness. These materials are also important for Fe-RAM
applications having large remanent polarization and low coercivity accompanied by high Curie
temperature for better performance and reliable operation. Present paper describes synthesis, dielectric
properties and impedance studies to reveal the important properties of barium substituted strontium
bismuth niobate, Sr0.85Ba0.15Bi2Nb2O9 in the system Sr1-xBaxBi2Nb2O9(x=0.15).
KEYWORDS
Bismuth layered Aurivillius type compounds, Ferroelectrics, Space charge polarization, Impedance
spectroscopy.
1. INTRODUCTION
Bismuth layered Aurivillius type compounds have a general formula [Bi2O2]2+
[An−1BnO3n+1]2−
(n=1, 2, 3, 4) consisting of perovskite [An−1 Bn O3n+1]2−
structure sandwiched between Para-electric
[Bi2O2]2+
layers. Here, A can be a divalent element like Ba2+
, Sr2+
, Pb2+
, Ca2+
etc. and B can be
Nb5+
, Ta5+
, Mo5+
, W6+
, Fe3+
, Ti4+
, V5+
etc [1,2,3,4]. Structurally, the Aurivillius phase is
typified by fluorite-like [Bi2O2]2+
interspersed between perovskite-like [An-1BnO3n+1]2−
layers
(where n represents the number of layers).The role of bismuth oxide layer in properties of these
ceramics has been found to be critical [5]. The bismuth oxide layer structured ferroelectrics may
become important piezoelectric ceramics because of their higher stability, higher operating
temperature (Tc = 550-650o
C), and higher operating frequency. These ceramics are mainly useful
for piezoelectric resonators which need to exhibit a very stable resonant frequency. In comparison
with non-layered perovskite ferroelectrics such as lead zirconate titanate (PZT), bismuth layer
structured ferroelectrics offer several advantages such as fatigue free, lead free, low operating
voltages; and most importantly, their ferroelectric properties are independent of film thickness.
For Fe-RAM applications, large remnant polarization and low coercivity accompanied by high
Curie temperature are required for better performance and reliable operation. These ceramics are
very sensitive to compositional variations. The properties of the layered perovskite ferroelectrics
can be enhanced by addition or substitution of alternative cations. Doping at different sites
modify the structure and influences properties of these materials. Aurivillius type bismuth layered
materials have received a lot of attention because of their application in ferroelectric non-volatile
2. International Journal of Recent advances in Physics (IJRAP) Vol.2, No.4, November 2013
36
random access memories. [6-8]. Recently, bismuth oxide layered perovskite materials, such as
SrBi2Nb2O9 (SBN), SrBi2Ta2O9 (SBT), and SrBi2(Nb,Ta)2O9 (SBTN), for Fe-RAM applications
have attracted an increasing attention in the research community, because they are fatigue-free
and lead-free and possess ferroelectric properties independent of film thickness [9-11]. Layered
perovskite ferroelectrics, however, suffer from two drawbacks: a relatively low remanent
polarization and a high processing temperature. Recently, efforts have been made to enhance the
properties of layered perovskite ferroelectrics by the addition or substitution of alternative
cations. For example, partial substitution of Sr2+
by Bi3+
has resulted in the most noticeable
improvement of ferroelectric properties. [12-13]. In present work was undertaken with an
objective to study the effect of partial substitution of strontium by barium in SrBi2Nb2O9 (SBN),
i.e. Sr1-xBaxBi2Nb2O9, an important bismuth layered perovskite compound. In present work,
composition Sr0.85Ba0.15Bi2Nb2O9 with x = 0.15 in the system Sr1-xBax Bi2Nb2O9 was prepared by
solid state reaction method and resulting ceramics were characterised by their dielectric
properties.
2. Experimental Details
The samples of the composition Sr0.85Ba0.15Bi2Nb2O9 in the system Sr1-xBaxBi2Nb2O9(x=0.15)
were prepared by conventional high temperature solid state ceramic method. In this method, the
appropriate amounts of compounds of constituent ions were weighed accurately using an
electronic single pan balance having accuracy 0.0001 gm. These weighed powders were
transferred in to an agate mortar, mixed and grounded finely for 04 hours using acetone as mixing
media to ensure effective, homogeneous mixing of all the starting powders. This homogeneous
mixed and dried powder was calcined in alumina crucible at 900 °C for three hours. The calcined
powder was again mixed and grounded for 02 hours with 5% solution of polyvinyl acetate as a
binder. This mixed powder was used to make cylindrical pellets of diameter 12 mm and thickness
in the range 2-3 mm with the help of die and hydraulic press. These prepared pellets were kept in
alumina boat and heated for sintering in a programmable high temperature furnace. The binder
from the pellet was first evaporated by slow heating up to 400 °C after which temperature of the
furnace was gradually increased to 1000°C and sintered for 03 hours. These samples were then
furnace cooled in air to room temperature. The two faces of the pellets were polished and coated
with a thin layer of conducting silver paste and dried at 100°C in air. The capacitance (C), Phase
angle θ and dielectric loss (D) was measured as a function of frequency at few selected
temperature using HIOKI 352-50 LCR Hi-tester using a computer interfaced measuring cell and
low temperature furnace.
Complex Impedance Spectroscopy
Generally, the impedance properties arises due to intra-grain, inter-grain and electrode processes.
The motion of charge carriers could occur in a variety of ways, namely charge displacement (by
long range and short range), dipole reorientation, space charge formation etc. The impedance
spectroscopy enables us to evaluate the relaxation frequency of the material. The relaxation
frequency of the material is only an intrinsic property of the material at a given temperature and is
independent of geometrical factors of the sample. The analysis of the electrical properties
(conductivity, dielectric constant, dielectric loss etc) carried out using relaxation frequency values
predict reliable properties. The complex impedance of a given material can be described by the
following relation: Z*(ω) = Z’(ω) + jZ”(ω). Here Z’ and Z” are ascribed to real and imaginary
parts of the total impedance. Recently, this technique has been successfully applied to analyze the
electrical properties of ceramic materials [14-17].
3. International Journal of Recent advances in Physics (IJRAP) Vol.2, No.4, November 2013
37
3. Results and discussion
Dielectric properties
The variation of dielectric constant with temperature at different frequencies is shown in figure-1.
It is observed from above plots that dielectric constant first increases with increase in temperature
and attains a maximum value at temperature 50 0
C. Again when temperature is increased above
50 0
C , then the value of dielectric constant decreases with increases with in temperature and
attains a minimum around 850
C. After that it increases rapidly with temperature. The magnitude
of the peak value of dielectric constant decreases with increase in frequency and peak becomes
more diffuse as a function of frequency. In higher temperature region, strong dispersion in
dielectric values is observed.
The figure-2 shows the variation of dielectric loss (tan against temperature at few
selected frequencies. The plot shows that the value of dielectric loss is high at lower
temperatures. It increases from room temperature and attained maximum around 50 0
C similar to
the trend observed in case of temperature variation of dielectric constant as shown in figure-1 and
then decreases with temperature. The peak value of dielectric loss decreases with increasing
frequency but peak occurs at same temperature which shows a temperature and frequency
independent relaxation process occurring in the material. In case of 10 KHz, another peak appears
in high temperature region.
Figure – 1: Dielectric constant versus temperature plot.
Figure - 2: Dielectric loss versus temperature plot
International Journal of Recent advances in Physics (IJRAP) Vol.2, No.4, November 2013
37
3. Results and discussion
Dielectric properties
The variation of dielectric constant with temperature at different frequencies is shown in figure-1.
It is observed from above plots that dielectric constant first increases with increase in temperature
and attains a maximum value at temperature 50 0
C. Again when temperature is increased above
50 0
C , then the value of dielectric constant decreases with increases with in temperature and
attains a minimum around 850
C. After that it increases rapidly with temperature. The magnitude
of the peak value of dielectric constant decreases with increase in frequency and peak becomes
more diffuse as a function of frequency. In higher temperature region, strong dispersion in
dielectric values is observed.
The figure-2 shows the variation of dielectric loss (tan against temperature at few
selected frequencies. The plot shows that the value of dielectric loss is high at lower
temperatures. It increases from room temperature and attained maximum around 50 0
C similar to
the trend observed in case of temperature variation of dielectric constant as shown in figure-1 and
then decreases with temperature. The peak value of dielectric loss decreases with increasing
frequency but peak occurs at same temperature which shows a temperature and frequency
independent relaxation process occurring in the material. In case of 10 KHz, another peak appears
in high temperature region.
Figure – 1: Dielectric constant versus temperature plot.
Figure - 2: Dielectric loss versus temperature plot
International Journal of Recent advances in Physics (IJRAP) Vol.2, No.4, November 2013
37
3. Results and discussion
Dielectric properties
The variation of dielectric constant with temperature at different frequencies is shown in figure-1.
It is observed from above plots that dielectric constant first increases with increase in temperature
and attains a maximum value at temperature 50 0
C. Again when temperature is increased above
50 0
C , then the value of dielectric constant decreases with increases with in temperature and
attains a minimum around 850
C. After that it increases rapidly with temperature. The magnitude
of the peak value of dielectric constant decreases with increase in frequency and peak becomes
more diffuse as a function of frequency. In higher temperature region, strong dispersion in
dielectric values is observed.
The figure-2 shows the variation of dielectric loss (tan against temperature at few
selected frequencies. The plot shows that the value of dielectric loss is high at lower
temperatures. It increases from room temperature and attained maximum around 50 0
C similar to
the trend observed in case of temperature variation of dielectric constant as shown in figure-1 and
then decreases with temperature. The peak value of dielectric loss decreases with increasing
frequency but peak occurs at same temperature which shows a temperature and frequency
independent relaxation process occurring in the material. In case of 10 KHz, another peak appears
in high temperature region.
Figure – 1: Dielectric constant versus temperature plot.
Figure - 2: Dielectric loss versus temperature plot
4. International Journal of Recent advances in Physics (IJRAP) Vol.2, No.4, November 2013
38
Figure – 3. Variation of Dielectric constant as a function of log of frequency
Figure – 4: Variation of Dielectric loss as a function of log of frequency
Figure - 3 shows the variation of the dielectric permittivity or dielectric constant with frequency
for the Sr0.85Ba0.15Bi2Nb2O9 at different temperatures. From this plot, it is clear that the
permittivity decreases monotonically with increasing frequency and attains a constant value at
higher frequencies. This is because, for polar materials, the initial value of the dielectric
permittivity is high, but as the frequency of the field is raised the value begins to drop, which
could be because the dipoles are not able to follow the field variation at higher frequencies, as
well as polarization effects (space charge). The low-frequency dispersion region is attributed to
charge accumulation at the electrode–electrolyte interface or in-homogeneities present in this
material during preparation process at micro-level. At higher frequencies, the periodic reversal of
the electric field occurs so fast that there is no excess ion diffusion in the direction of the field.
Hence, the dielectric permittivity (ε) decreases with increasing frequency in our samples. The
measured series capacitance, Cs is given by
Where C′ is the frequency-independent capacitance, R is the temperature-dependent resistance,
and ω is 2πf. The above equation predicts that Cs should decrease with increasing frequency f,
International Journal of Recent advances in Physics (IJRAP) Vol.2, No.4, November 2013
38
Figure – 3. Variation of Dielectric constant as a function of log of frequency
Figure – 4: Variation of Dielectric loss as a function of log of frequency
Figure - 3 shows the variation of the dielectric permittivity or dielectric constant with frequency
for the Sr0.85Ba0.15Bi2Nb2O9 at different temperatures. From this plot, it is clear that the
permittivity decreases monotonically with increasing frequency and attains a constant value at
higher frequencies. This is because, for polar materials, the initial value of the dielectric
permittivity is high, but as the frequency of the field is raised the value begins to drop, which
could be because the dipoles are not able to follow the field variation at higher frequencies, as
well as polarization effects (space charge). The low-frequency dispersion region is attributed to
charge accumulation at the electrode–electrolyte interface or in-homogeneities present in this
material during preparation process at micro-level. At higher frequencies, the periodic reversal of
the electric field occurs so fast that there is no excess ion diffusion in the direction of the field.
Hence, the dielectric permittivity (ε) decreases with increasing frequency in our samples. The
measured series capacitance, Cs is given by
Where C′ is the frequency-independent capacitance, R is the temperature-dependent resistance,
and ω is 2πf. The above equation predicts that Cs should decrease with increasing frequency f,
International Journal of Recent advances in Physics (IJRAP) Vol.2, No.4, November 2013
38
Figure – 3. Variation of Dielectric constant as a function of log of frequency
Figure – 4: Variation of Dielectric loss as a function of log of frequency
Figure - 3 shows the variation of the dielectric permittivity or dielectric constant with frequency
for the Sr0.85Ba0.15Bi2Nb2O9 at different temperatures. From this plot, it is clear that the
permittivity decreases monotonically with increasing frequency and attains a constant value at
higher frequencies. This is because, for polar materials, the initial value of the dielectric
permittivity is high, but as the frequency of the field is raised the value begins to drop, which
could be because the dipoles are not able to follow the field variation at higher frequencies, as
well as polarization effects (space charge). The low-frequency dispersion region is attributed to
charge accumulation at the electrode–electrolyte interface or in-homogeneities present in this
material during preparation process at micro-level. At higher frequencies, the periodic reversal of
the electric field occurs so fast that there is no excess ion diffusion in the direction of the field.
Hence, the dielectric permittivity (ε) decreases with increasing frequency in our samples. The
measured series capacitance, Cs is given by
Where C′ is the frequency-independent capacitance, R is the temperature-dependent resistance,
and ω is 2πf. The above equation predicts that Cs should decrease with increasing frequency f,
5. International Journal of Recent advances in Physics (IJRAP) Vol.2, No.4, November 2013
39
eventually tending to a constant value C′ for all temperatures and at any given frequency. Since
the permittivity is directly proportional to Cs, the permittivity should decrease with increasing
frequency.
The figure - 4 gives the variation of dielectric loss as function of log of frequency at various
temperatures. A peak appears in dielectric loss versus log f plot which shift to higher frequency
with increasing temperature. These peaks indicate the transition from short range to long range
mobility with decreasing frequency by hopping from one site to neighbouring sites whereas for
high frequency region ions are spatially confined and can execute only localised motion.
Figure – 5: Variation of relaxation time against 1000/T
The variation of dielectric loss against log of frequency at different temperatures of measurement
as shown in figure - 4, the dielectric loss variation with frequency shows a peak with a slightly
asymmetrically broadened at each temperature, the broadening increasing with increase in
temperature. The asymmetric broadening of the peaks suggests the presence of electrical
processes in the material with a spread of relaxation time. In a relaxation system, one can
determine the most probable relaxation time (τ) from the position of the loss peak in the D versus
log (ƒ) plots according to the relation
τ=1/ω=1/2πf
where ƒ is the relaxation frequency. Figure 5 shows the variation of relaxation time {ln (τ)} with
103
/ T (K−1
). It appears to follow the Arrhenius relation; τ=τ0 exp (-Ea/kT), where τ0 is the pre-
exponential factor, k is the Boltzmann constant and T the absolute temperature. The value of
activation energy (Ea) as calculated from the slope of log (τ) versus 103
/T curve is found to be
0.26 eV.
International Journal of Recent advances in Physics (IJRAP) Vol.2, No.4, November 2013
39
eventually tending to a constant value C′ for all temperatures and at any given frequency. Since
the permittivity is directly proportional to Cs, the permittivity should decrease with increasing
frequency.
The figure - 4 gives the variation of dielectric loss as function of log of frequency at various
temperatures. A peak appears in dielectric loss versus log f plot which shift to higher frequency
with increasing temperature. These peaks indicate the transition from short range to long range
mobility with decreasing frequency by hopping from one site to neighbouring sites whereas for
high frequency region ions are spatially confined and can execute only localised motion.
Figure – 5: Variation of relaxation time against 1000/T
The variation of dielectric loss against log of frequency at different temperatures of measurement
as shown in figure - 4, the dielectric loss variation with frequency shows a peak with a slightly
asymmetrically broadened at each temperature, the broadening increasing with increase in
temperature. The asymmetric broadening of the peaks suggests the presence of electrical
processes in the material with a spread of relaxation time. In a relaxation system, one can
determine the most probable relaxation time (τ) from the position of the loss peak in the D versus
log (ƒ) plots according to the relation
τ=1/ω=1/2πf
where ƒ is the relaxation frequency. Figure 5 shows the variation of relaxation time {ln (τ)} with
103
/ T (K−1
). It appears to follow the Arrhenius relation; τ=τ0 exp (-Ea/kT), where τ0 is the pre-
exponential factor, k is the Boltzmann constant and T the absolute temperature. The value of
activation energy (Ea) as calculated from the slope of log (τ) versus 103
/T curve is found to be
0.26 eV.
International Journal of Recent advances in Physics (IJRAP) Vol.2, No.4, November 2013
39
eventually tending to a constant value C′ for all temperatures and at any given frequency. Since
the permittivity is directly proportional to Cs, the permittivity should decrease with increasing
frequency.
The figure - 4 gives the variation of dielectric loss as function of log of frequency at various
temperatures. A peak appears in dielectric loss versus log f plot which shift to higher frequency
with increasing temperature. These peaks indicate the transition from short range to long range
mobility with decreasing frequency by hopping from one site to neighbouring sites whereas for
high frequency region ions are spatially confined and can execute only localised motion.
Figure – 5: Variation of relaxation time against 1000/T
The variation of dielectric loss against log of frequency at different temperatures of measurement
as shown in figure - 4, the dielectric loss variation with frequency shows a peak with a slightly
asymmetrically broadened at each temperature, the broadening increasing with increase in
temperature. The asymmetric broadening of the peaks suggests the presence of electrical
processes in the material with a spread of relaxation time. In a relaxation system, one can
determine the most probable relaxation time (τ) from the position of the loss peak in the D versus
log (ƒ) plots according to the relation
τ=1/ω=1/2πf
where ƒ is the relaxation frequency. Figure 5 shows the variation of relaxation time {ln (τ)} with
103
/ T (K−1
). It appears to follow the Arrhenius relation; τ=τ0 exp (-Ea/kT), where τ0 is the pre-
exponential factor, k is the Boltzmann constant and T the absolute temperature. The value of
activation energy (Ea) as calculated from the slope of log (τ) versus 103
/T curve is found to be
0.26 eV.
6. International Journal of Recent advances in Physics (IJRAP) Vol.2, No.4, November 2013
40
Figure - 6 Frequency dependence of (a) real (Z’) , (b) imaginary (Z’’) parts of total impedance.
Figure 6(a) presents the variation of the log of real part impedance (Z’) versus log of frequency
at several temperatures. From the plot it is observed that the Z’ decreases slowly in the frequency
range of 1.00 KHz, depending on the temperature, and continuously with an increase in
frequency. Figure 6(b) shows the variation of the log of imaginary part of the impedance (Z”) as a
function of log of frequency at several temperatures. It shows appearance of peaks at a
characteristic frequency dependent on temperature and can be related to the type and strength of
the relaxation phenomenon occurring in the material. It can be seen that the curves display broad
and low intensity peaks. The peak appears to shift with change in temperature indicating
distribution of relaxation times over wide range of frequency. The magnitude of Z” maximum
decreases with temperature indicating increasing loss in the sample due to resistive property of
the sample. This behaviour of impedance plot arises possibly due to the presence of space charge
in the material.
Figure – 7: Variation of log of imaginary part and real part of total impedance against log of frequency at
several temperatures.
The real and imaginary part of the dielectric constant is plotted as a function of frequency are
shown in figure-7 at few selected temperatures . It is observed from these plots that both the real
and imaginary parts of dielectric constant show strong frequency dependentce in lower frequency
range . This is a common features of dielectrics associated with inoic conductivity contribution
and is reffered as the low frequency dielectric dispersion. The dispersion in ε’’ is stonger than that
in ε’ imploying that it is influnced by dc conductivity which is dominating in low frequency
region due to space charge polarization. Both the curves representing log of imaginary and real
parts of dielectric constant intersects each other when plotted against log of freqency. The
frequency at which they intersect each other decreases as one goes away from temperature at
which dielectric peak occurs in dielectric constant versus temperature plot. When temperature is
well away from this peak temperature, they do not intersect each other. The high value of e’ and
International Journal of Recent advances in Physics (IJRAP) Vol.2, No.4, November 2013
40
Figure - 6 Frequency dependence of (a) real (Z’) , (b) imaginary (Z’’) parts of total impedance.
Figure 6(a) presents the variation of the log of real part impedance (Z’) versus log of frequency
at several temperatures. From the plot it is observed that the Z’ decreases slowly in the frequency
range of 1.00 KHz, depending on the temperature, and continuously with an increase in
frequency. Figure 6(b) shows the variation of the log of imaginary part of the impedance (Z”) as a
function of log of frequency at several temperatures. It shows appearance of peaks at a
characteristic frequency dependent on temperature and can be related to the type and strength of
the relaxation phenomenon occurring in the material. It can be seen that the curves display broad
and low intensity peaks. The peak appears to shift with change in temperature indicating
distribution of relaxation times over wide range of frequency. The magnitude of Z” maximum
decreases with temperature indicating increasing loss in the sample due to resistive property of
the sample. This behaviour of impedance plot arises possibly due to the presence of space charge
in the material.
Figure – 7: Variation of log of imaginary part and real part of total impedance against log of frequency at
several temperatures.
The real and imaginary part of the dielectric constant is plotted as a function of frequency are
shown in figure-7 at few selected temperatures . It is observed from these plots that both the real
and imaginary parts of dielectric constant show strong frequency dependentce in lower frequency
range . This is a common features of dielectrics associated with inoic conductivity contribution
and is reffered as the low frequency dielectric dispersion. The dispersion in ε’’ is stonger than that
in ε’ imploying that it is influnced by dc conductivity which is dominating in low frequency
region due to space charge polarization. Both the curves representing log of imaginary and real
parts of dielectric constant intersects each other when plotted against log of freqency. The
frequency at which they intersect each other decreases as one goes away from temperature at
which dielectric peak occurs in dielectric constant versus temperature plot. When temperature is
well away from this peak temperature, they do not intersect each other. The high value of e’ and
International Journal of Recent advances in Physics (IJRAP) Vol.2, No.4, November 2013
40
Figure - 6 Frequency dependence of (a) real (Z’) , (b) imaginary (Z’’) parts of total impedance.
Figure 6(a) presents the variation of the log of real part impedance (Z’) versus log of frequency
at several temperatures. From the plot it is observed that the Z’ decreases slowly in the frequency
range of 1.00 KHz, depending on the temperature, and continuously with an increase in
frequency. Figure 6(b) shows the variation of the log of imaginary part of the impedance (Z”) as a
function of log of frequency at several temperatures. It shows appearance of peaks at a
characteristic frequency dependent on temperature and can be related to the type and strength of
the relaxation phenomenon occurring in the material. It can be seen that the curves display broad
and low intensity peaks. The peak appears to shift with change in temperature indicating
distribution of relaxation times over wide range of frequency. The magnitude of Z” maximum
decreases with temperature indicating increasing loss in the sample due to resistive property of
the sample. This behaviour of impedance plot arises possibly due to the presence of space charge
in the material.
Figure – 7: Variation of log of imaginary part and real part of total impedance against log of frequency at
several temperatures.
The real and imaginary part of the dielectric constant is plotted as a function of frequency are
shown in figure-7 at few selected temperatures . It is observed from these plots that both the real
and imaginary parts of dielectric constant show strong frequency dependentce in lower frequency
range . This is a common features of dielectrics associated with inoic conductivity contribution
and is reffered as the low frequency dielectric dispersion. The dispersion in ε’’ is stonger than that
in ε’ imploying that it is influnced by dc conductivity which is dominating in low frequency
region due to space charge polarization. Both the curves representing log of imaginary and real
parts of dielectric constant intersects each other when plotted against log of freqency. The
frequency at which they intersect each other decreases as one goes away from temperature at
which dielectric peak occurs in dielectric constant versus temperature plot. When temperature is
well away from this peak temperature, they do not intersect each other. The high value of e’ and
7. International Journal of Recent advances in Physics (IJRAP) Vol.2, No.4, November 2013
41
e” in low frequency region shows the effect of space charge polarization and conducting ion
motion.
Figure – 8: The variation of z’’ against z’ at various temperatures.
Figure -8 shows the impedance plot (Z” versus Z”) at eight different temperaature. The
impedance plot at temperature 50 0
C shows that there is a depressed semicircle in high frequency
range. When the temperature increases from 50 0
C , a second semicircle start appearing in low
frequency region. The above plots composed of two semicircle, a small semicircle at high
frequency indicates the effect of grain and large semicircle at low frequency indicates the of grain
boundary effect. The intercept of of the semicircle on real axis gives the resistance of the grain
(Rb) and grain boundary (Rgb) of the corresponding component contributing towords the
impedance of the sample. It is also observed that resistance (grain) corresponding to first
semicircle continously decreasing with increase in temperature. The same trend is observed at
higher temperature also.
The observed depressed semicircle are in high frequency region indicates that there is distribution
of relaxation times in the material. This is also indicative of the presence of both localised and
non localised conduction process in the material.
The observed dielectric properties of the material can be explain using impedance data. As
temperature increase the difference in resistance grain and grain boundary increases which cause
large conductivity difference in material at microlevels. This difference in conductivity gives rise
to space charge at microlevels, hence large value of dielectric constant at high temperature is
observed in the material. The strong frequency dependence of dielectric properties is due to
formation of space charge.
4. ACKNOWLEDGEMENTS
Authors are thankful to Guru Ghasidas Vishwavidyalaya, Bilaspur and one of us (HST) is
thankful to University grant Commission, New Delhi for financial asisstance.
8. International Journal of Recent advances in Physics (IJRAP) Vol.2, No.4, November 2013
42
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