Abstract Fe2O3 nanoparticles have been prepared by a simple solvothermal method using a domestic microwave oven. X-ray powder diffraction measurement indicates the amorphous nature of the as-prepared sample. Calcined samples were obtained by annealing the as-prepared sample at different temperatures, viz. 400, 500, 600 and 700oC. Transmission electron microscopic images indicate that all the five samples are spherical in shape. AC electrical measurements were carried out on pelletized samples by the parallel plate capacitor method at various temperatures ranging from 40-130oC and frequencies ranging from 100 Hz -1 MHz. Results indicate low AC electrical conductivities and consequently show the occurrence of nano confined states. The exciton Bohr radii obtained from the dielectric constant values at 40oC temperature and 1 kHz frequency are 41.8, 54.8, 55.3, 56.3 and 27.0 respectively for the as-prepared sample and samples calcined at 400, 500, 600 and 700oC which indicate a strong quantum confinement effect. The impedance spectra observed exhibit non-ideal behavior. Keywords: Semiconductors, Magnetic materials, Nanoparticles, Electrical properties
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.
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
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 facile method to prepare CdO-Mn3O4 nanocompositeIOSR Journals
CdO-Mn3O4 nanocomposite has been prepared by a simple solvothermal method using a domestic microwave oven. Cadmium acetate, manganese acetate and urea were used as the precursors and ethylene glycol as the solvent. The as-prepared sample was annealed for 1 hour in each case at different temperatures, viz. 100, 200 and 300°C. The as-prepared and annealed samples were characterized by X-ray diffraction and scanning electron microscopic analyses. Results indicate that annealing at 300°C is required to get the sample with high phase purity and homogeneity. The present study indicates that the method adopted can be considered as an economical and scalable one to prepare the proposed nanocomposite with reduced size, phase purity and homogeneity.
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.
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.
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
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 facile method to prepare CdO-Mn3O4 nanocompositeIOSR Journals
CdO-Mn3O4 nanocomposite has been prepared by a simple solvothermal method using a domestic microwave oven. Cadmium acetate, manganese acetate and urea were used as the precursors and ethylene glycol as the solvent. The as-prepared sample was annealed for 1 hour in each case at different temperatures, viz. 100, 200 and 300°C. The as-prepared and annealed samples were characterized by X-ray diffraction and scanning electron microscopic analyses. Results indicate that annealing at 300°C is required to get the sample with high phase purity and homogeneity. The present study indicates that the method adopted can be considered as an economical and scalable one to prepare the proposed nanocomposite with reduced size, phase purity and homogeneity.
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.
Studies of the Atomic and Crystalline Characteristics of Ceramic Oxide Nano P...albertdivis
In the present study, some transition metal oxides (Zinc oxide, iron oxide and copper oxide) which are widely used in the fabrication of electronic devices were selected and subjected to biofield treatment.
Studies of the Atomic and Crystalline Characteristics of Ceramic Oxide Nano P...Mahendra Kumar Trivedi
In the present study, some transition metal oxides (Zinc oxide, iron oxide and copper oxide) which are widely used in the fabrication of electronic devices were selected and subjected to biofield treatment.
Dielectric properties of pure and ni2+ doped glycine sodium sulfate crystalseSAT Journals
Abstract Pure and Ni2+ added glycine sodium sulfate (GSS) single crystals were grown by the slow evaporation technique and characterized chemically, structurally, thermally, optically, mechanically and electrically. Effect of Ni2+ addition as an impurity on the properties of GSS has also been investigated. All the six crystals grown exhibit normal dielectric behavior and are found to be thermally stable up to 250˚C, NLO active and mechanically soft. The Ni2+ addition is found to increase the dielectric parameters. The low dielectric constant values observed for pure GSS indicate that GSS is not only a promising NLO material but also a low dielectric constant value dielectric material. Keywords: Activation energy, Crystal growth, Dielectric crystal, Electrical properties, X-ray diffraction
Properties of electrodeposited semiconductor thin films are dependent upon the electrolyte composition, plating time, and temperature as well as the current density and the nature of the substrate. In this study, the influence of electrodeposition parameters such as deposition voltage, deposition time, composition of solution, and deposition temperature upon the properties of In2S3 films were analyzed by the Taguchi Method. According to Taguchi analysis, the interaction between deposition voltage and deposition time was significant. Deposition voltage had the most impact upon the stoichiometry of In2S3 films and deposition temperature had the least impact. The stochiometric ratios between sulfur and indium (S/In : 3/2) obtained from experiments performed with optimized electrodeposition paramters were in agreement with predicted values from the Taguchi Method. The experiments were carried-out according to Taguchi Orthogonal Array L27 (3^4) Design of Experiments (DOE). Approximately 600 nm-thick In2S3 films were electrodeposited from an organic bath (ethylene glycol-based) containing indium chloride (InCl3), sodium chloride (NaCl), and sodium thiosulfate (Na2S2O3.5H2O), the latter used as an additional sulfur source along with elemental sulfur (S). An X-ray diffractometer (XRD), energy dispersive X-ray spectroscopy (EDS) unit, and scanning electron microscope (SEM) were respectively used to analyze the phases, elemental composition, and morphology of the electrodeposited In2S3 films.
Computations of Acoustic Wave Propagation in II-VI Hexagonal Semiconductor Compounds
Original Research Article
Journal of Chemistry and Materials Research Vol. 1 (3), 2014, 65–70
Pramod Kumar Yadawa *
Statistical analysis of electrodeposited in2 s3 films techconnect conferenceArkansas State University
In2S3 has received attention as an alternative to CdS as the buffer layer in heterojunction solar cells. Although having a bandgap of 2.0 eV relative to 2.5 eV for CdS, the lower toxicity and environmental impact of indium relative to cadmium, and significant photosensitivity, compel ongoing research [1]. Indium sulfide thin films were deposited onto molybdenum-coated glass (SiO2) substrates by electrodeposition from organic baths (ethylene glycol-based) containing indium chloride (InCl3), sodium chloride (NaCl), and sodium thiosulfate (Na2S2O3.5H2O), the latter used as an additional sulfur source along with elemental sulfur (S). The Taguchi method was used to optimize the deposition paramters so as to minimize non-uniformity, cracks, and improper stoichiometry. The measured performance characteristics (molar ratio (In:S) and crack density) for all of the In2S3 films were calculated to analyze the effect of each deposition factor (deposition voltage, deposition temperature, composition of solution, and deposition time) involved in the electrodeposition process by calculating the sensitivity (signal to noise, S/N, ratios).
Studies on in-Doped Zno Transparent Conducting thin FilmsIJRESJOURNAL
ABSTRACT: In this manuscript we have investigated the influences of indium dopants on zinc oxide (ZnO) thin films regarding physico-chemical properties for application in modern conducting devices. As a starting material, Indium (III) chloride, and Zn(CH3COO)2⋅2H2O were used. The complex TSDC spectrum was obtained by submitting the sample to a constant electrical field Ep = 10M V/m during 2 min at a varing polarization temperature of Tmax = 1500C. A minimal sheet resistance with electrical resistivity as low in the range of 10-3 Ω·cm was found for this thin film.
Synthesis and analysis of electrical properties of Lead free Ba3Sr2LaTi3V7O30...inventy
Materials of tungsten-bronze (TB) structure belong to an important family of dielectric materials which are well known for their applications in various electrical devices, such as transducers, actuators, capacitors, and ferroelectric random access memory. The TB structure consists of a framework of distorted BO6 octahedral sharing corners in such a way that three different types of interstices (A, B and C) are available for a wide variety of cations occupying in a general formula (A1)2(A2)4(C)4(B1)2(B2)8O30. Our present work deals with the studies of preparation and characterization of the physical properties of a novel single-phase polycrystalline lead-free vanadate having Tungsten Bronze Structure with compound formula Ba3Sr2LaTi3V7O30.The X-ray diffraction analysis confirms the formation of single-phase compound with orthorhombic structure. The effect of temperature (32- 5000C) and frequency (102–106 Hz) on structural and electrical properties were studied using an impedance analyzer. Detailed studies of impedance parameters provide a better understanding of the electrical properties and type of relaxation processes in the material. The bulk resistance is observed to be decreased with rise in temperature showing a typical negative temperature coefficient of resistance (NTCR) behavior.
Study of Structural and Dielectric properties of BaTiO3 Doped with Mg-Cu-Zn F...IJSRD
The magnetoelectric (ME) composites having the general formula, (x) Mg0.25Cu0.25Zn0.5Fe2O4 + (1-x) BaTiO3 (x=15%, 30%, 45%) were synthesized by sintering mixtures of highly ferroelectric BaTiO3 and highly magnetostrictive magnetic component Mg0.25Cu0.25Zn0.5Fe2O4. The presence of constituent phases of ferrite, ferroelectric and their composites were confirmed by X-ray diffraction (XRD) studies. Surface morphology of the samples has been investigated using Field Emission Scanning Electron Microscope (FESEM), which revealed uniform mixing of two phases. The variations in dielectric constant and dissipation factor as a function of frequency from 100 Hz to 1 MHz were measured in a Hioki LCR Hi-Tester. The dielectric constant and dielectric loss were found to decrease rapidly in the low frequency region and became almost constant in the high frequency region. The electrical conductivity deduced from the measured dielectric parameters has been analyzed and found that the conduction mechanism in these composites is in conformity with small polaron hopping model.
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.
Microstructural and electrical study of eSAT Journals
Abstract Ceramics of (Ba0.6Sr0.4)(Zr1-xTix)O3 (x=0.40,0.50) samples were prepared by solid state reaction method. Micro structural study was performed by scanning electron microscope revealed the particle sizes are in the range of 0.8 μm. The structures are irregular in shape. Dc resistivity property was studied with respect to temperature from room temperature to 673 K. temperature of maximum resistivity (Tmax) are around 443 K and 378 K. dc dielectric constant, ac dielectric constant and dielectric loss were studied with respect to temperature from room temperature to 673 K at 100 Hz frequency. At higher temperature the dielectric constant of BSZT40 and BSZT50 is high. In the low frequency range dissipation factor is determined by the influence of ion conductivity. Index Terms: Ceramics, Barium Zirconate, Microstructure, DC Resistivity, Dielectric Constant and Dielectric loss
Zno and znopbs heterojunction photo electrochemical cellseSAT Journals
Abstract Photo Electrochemical Cell (PEC) can also be used for splitting of water into hydrogen and Oxygen. Here, ZnO nanorod PEC has been prepared in hydrothermal method and ZnO/PbS quantum dot PEC has been prepared by hydrothermal method and chemical bath deposition method. UV-Visible spectroscopy has been observed. Flat band voltage, bandwidth and majority charge carriers have been calculated from Mott-Schottky. Impedance variation at semiconductor and electrolyte junction has been observed with Electrochemical Impedance Spectroscopy (EIS). Keywords: Hydrothermal, Chemical bath, ZnO/PbS, UV-Vis, Mott-Schottky, EIS.
A Nano Capacitor Including Graphene Layers Composed with Doped Boron and Nitr...CrimsonPublishersRDMS
A Nano Capacitor Including Graphene Layers Composed with Doped Boron and Nitrogen by Majid Monajjemi* in Crimson Publishers: Peer Reviewed Material Science Journals
IMPROVEMENT IN MORPHOLOGICAL AND ELECTRO-MAGNETIC BEHAVIOUR OF HARD FERRITE P...Editor IJMTER
The Ni-Ir substituted strontium ferrite of Sr(Ni-Ir)xFe12-2xO19 (x = 0.02 & 0.08) were
synthesized by sol-gel auto combustion technique and characterized using X-ray diffraction (XRD),
Transmission Electron Microscopy (TEM) for morphological behaviour with electrical
characteristics using Impedance Analyzer. XRD results confirmed the formation of a single phase
M-type hexagonal unit cell of space group P63/mmc. The increase in Ni-Ir concentration increases
the lattice parameter. TEM analysis of the sample demonstrates the formation of nano-size particles
which decreases with substitution. In this paper we reported the variation of dielectric constant,
dielectric loss, tangent loss, conductivity and magnetic behaviour with composition with temperature
and frequency analysis of the sample. The migration of Fe3+ ion from octahedral to tetrahedral site
decreases the dielectric constant with increase in Ni-Ir concentration. Activation energies were
found similar with calculated at ferromagnetic and paramagnetic region. The material study we
confined that the activation energy in the paramagnetic region is higher than that in the
ferromagnetic region. The enhanced resistivity of Ni-Ir substituted strontium hexaferrites is a
prospective application in high frequency and in microwave devices development.
Microstructural and Dielectric Characterization of Sr doped Ba(Fe0.5Ta0.5)O3 ...theijes
Solid state reaction method was used to synthesize Ba1-xSrx(Fe0.5Ta0.5)O3 ceramic(x=0, 0.1, 0.2, 0.3, 0.4 and 0.5). The raw materials of making Sr doped Ba(Fe0.5Ta0.5)O3 were BaCO3, SrCO3, Fe2O3, Ta2O5 (purity better than 99%). Pellet and ring shaped samples prepared from each composition were sintered at 1400 and 1450ºC for 5 hour. The phase formation of Ba1-xSrx(Fe0.5Ta0.5)O3 was checked using X-ray diffraction (XRD) technique and observed a cubic perovskite crystal structure in space group Pm3m (221). Microstructure of the individual compound was examined by the field emission scanning electron micrograph (FESEM). Grain size was found to be varied with Sr content. The lattice parameter decreased with increasing Sr content. Dielectric spectroscopy was applied to investigate the electrical properties of BSFT at room temperature and in a frequency range of 100Hz–100 MHz. An analysis of the dielectric constant εʹ and loss tangent tan with frequency was performed assuming a distribution of relaxation times. The low frequency dielectric dispersion corresponds to the DC electrical conductivity.
Studies of the Atomic and Crystalline Characteristics of Ceramic Oxide Nano P...albertdivis
In the present study, some transition metal oxides (Zinc oxide, iron oxide and copper oxide) which are widely used in the fabrication of electronic devices were selected and subjected to biofield treatment.
Studies of the Atomic and Crystalline Characteristics of Ceramic Oxide Nano P...Mahendra Kumar Trivedi
In the present study, some transition metal oxides (Zinc oxide, iron oxide and copper oxide) which are widely used in the fabrication of electronic devices were selected and subjected to biofield treatment.
Dielectric properties of pure and ni2+ doped glycine sodium sulfate crystalseSAT Journals
Abstract Pure and Ni2+ added glycine sodium sulfate (GSS) single crystals were grown by the slow evaporation technique and characterized chemically, structurally, thermally, optically, mechanically and electrically. Effect of Ni2+ addition as an impurity on the properties of GSS has also been investigated. All the six crystals grown exhibit normal dielectric behavior and are found to be thermally stable up to 250˚C, NLO active and mechanically soft. The Ni2+ addition is found to increase the dielectric parameters. The low dielectric constant values observed for pure GSS indicate that GSS is not only a promising NLO material but also a low dielectric constant value dielectric material. Keywords: Activation energy, Crystal growth, Dielectric crystal, Electrical properties, X-ray diffraction
Properties of electrodeposited semiconductor thin films are dependent upon the electrolyte composition, plating time, and temperature as well as the current density and the nature of the substrate. In this study, the influence of electrodeposition parameters such as deposition voltage, deposition time, composition of solution, and deposition temperature upon the properties of In2S3 films were analyzed by the Taguchi Method. According to Taguchi analysis, the interaction between deposition voltage and deposition time was significant. Deposition voltage had the most impact upon the stoichiometry of In2S3 films and deposition temperature had the least impact. The stochiometric ratios between sulfur and indium (S/In : 3/2) obtained from experiments performed with optimized electrodeposition paramters were in agreement with predicted values from the Taguchi Method. The experiments were carried-out according to Taguchi Orthogonal Array L27 (3^4) Design of Experiments (DOE). Approximately 600 nm-thick In2S3 films were electrodeposited from an organic bath (ethylene glycol-based) containing indium chloride (InCl3), sodium chloride (NaCl), and sodium thiosulfate (Na2S2O3.5H2O), the latter used as an additional sulfur source along with elemental sulfur (S). An X-ray diffractometer (XRD), energy dispersive X-ray spectroscopy (EDS) unit, and scanning electron microscope (SEM) were respectively used to analyze the phases, elemental composition, and morphology of the electrodeposited In2S3 films.
Computations of Acoustic Wave Propagation in II-VI Hexagonal Semiconductor Compounds
Original Research Article
Journal of Chemistry and Materials Research Vol. 1 (3), 2014, 65–70
Pramod Kumar Yadawa *
Statistical analysis of electrodeposited in2 s3 films techconnect conferenceArkansas State University
In2S3 has received attention as an alternative to CdS as the buffer layer in heterojunction solar cells. Although having a bandgap of 2.0 eV relative to 2.5 eV for CdS, the lower toxicity and environmental impact of indium relative to cadmium, and significant photosensitivity, compel ongoing research [1]. Indium sulfide thin films were deposited onto molybdenum-coated glass (SiO2) substrates by electrodeposition from organic baths (ethylene glycol-based) containing indium chloride (InCl3), sodium chloride (NaCl), and sodium thiosulfate (Na2S2O3.5H2O), the latter used as an additional sulfur source along with elemental sulfur (S). The Taguchi method was used to optimize the deposition paramters so as to minimize non-uniformity, cracks, and improper stoichiometry. The measured performance characteristics (molar ratio (In:S) and crack density) for all of the In2S3 films were calculated to analyze the effect of each deposition factor (deposition voltage, deposition temperature, composition of solution, and deposition time) involved in the electrodeposition process by calculating the sensitivity (signal to noise, S/N, ratios).
Studies on in-Doped Zno Transparent Conducting thin FilmsIJRESJOURNAL
ABSTRACT: In this manuscript we have investigated the influences of indium dopants on zinc oxide (ZnO) thin films regarding physico-chemical properties for application in modern conducting devices. As a starting material, Indium (III) chloride, and Zn(CH3COO)2⋅2H2O were used. The complex TSDC spectrum was obtained by submitting the sample to a constant electrical field Ep = 10M V/m during 2 min at a varing polarization temperature of Tmax = 1500C. A minimal sheet resistance with electrical resistivity as low in the range of 10-3 Ω·cm was found for this thin film.
Synthesis and analysis of electrical properties of Lead free Ba3Sr2LaTi3V7O30...inventy
Materials of tungsten-bronze (TB) structure belong to an important family of dielectric materials which are well known for their applications in various electrical devices, such as transducers, actuators, capacitors, and ferroelectric random access memory. The TB structure consists of a framework of distorted BO6 octahedral sharing corners in such a way that three different types of interstices (A, B and C) are available for a wide variety of cations occupying in a general formula (A1)2(A2)4(C)4(B1)2(B2)8O30. Our present work deals with the studies of preparation and characterization of the physical properties of a novel single-phase polycrystalline lead-free vanadate having Tungsten Bronze Structure with compound formula Ba3Sr2LaTi3V7O30.The X-ray diffraction analysis confirms the formation of single-phase compound with orthorhombic structure. The effect of temperature (32- 5000C) and frequency (102–106 Hz) on structural and electrical properties were studied using an impedance analyzer. Detailed studies of impedance parameters provide a better understanding of the electrical properties and type of relaxation processes in the material. The bulk resistance is observed to be decreased with rise in temperature showing a typical negative temperature coefficient of resistance (NTCR) behavior.
Study of Structural and Dielectric properties of BaTiO3 Doped with Mg-Cu-Zn F...IJSRD
The magnetoelectric (ME) composites having the general formula, (x) Mg0.25Cu0.25Zn0.5Fe2O4 + (1-x) BaTiO3 (x=15%, 30%, 45%) were synthesized by sintering mixtures of highly ferroelectric BaTiO3 and highly magnetostrictive magnetic component Mg0.25Cu0.25Zn0.5Fe2O4. The presence of constituent phases of ferrite, ferroelectric and their composites were confirmed by X-ray diffraction (XRD) studies. Surface morphology of the samples has been investigated using Field Emission Scanning Electron Microscope (FESEM), which revealed uniform mixing of two phases. The variations in dielectric constant and dissipation factor as a function of frequency from 100 Hz to 1 MHz were measured in a Hioki LCR Hi-Tester. The dielectric constant and dielectric loss were found to decrease rapidly in the low frequency region and became almost constant in the high frequency region. The electrical conductivity deduced from the measured dielectric parameters has been analyzed and found that the conduction mechanism in these composites is in conformity with small polaron hopping model.
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.
Microstructural and electrical study of eSAT Journals
Abstract Ceramics of (Ba0.6Sr0.4)(Zr1-xTix)O3 (x=0.40,0.50) samples were prepared by solid state reaction method. Micro structural study was performed by scanning electron microscope revealed the particle sizes are in the range of 0.8 μm. The structures are irregular in shape. Dc resistivity property was studied with respect to temperature from room temperature to 673 K. temperature of maximum resistivity (Tmax) are around 443 K and 378 K. dc dielectric constant, ac dielectric constant and dielectric loss were studied with respect to temperature from room temperature to 673 K at 100 Hz frequency. At higher temperature the dielectric constant of BSZT40 and BSZT50 is high. In the low frequency range dissipation factor is determined by the influence of ion conductivity. Index Terms: Ceramics, Barium Zirconate, Microstructure, DC Resistivity, Dielectric Constant and Dielectric loss
Zno and znopbs heterojunction photo electrochemical cellseSAT Journals
Abstract Photo Electrochemical Cell (PEC) can also be used for splitting of water into hydrogen and Oxygen. Here, ZnO nanorod PEC has been prepared in hydrothermal method and ZnO/PbS quantum dot PEC has been prepared by hydrothermal method and chemical bath deposition method. UV-Visible spectroscopy has been observed. Flat band voltage, bandwidth and majority charge carriers have been calculated from Mott-Schottky. Impedance variation at semiconductor and electrolyte junction has been observed with Electrochemical Impedance Spectroscopy (EIS). Keywords: Hydrothermal, Chemical bath, ZnO/PbS, UV-Vis, Mott-Schottky, EIS.
A Nano Capacitor Including Graphene Layers Composed with Doped Boron and Nitr...CrimsonPublishersRDMS
A Nano Capacitor Including Graphene Layers Composed with Doped Boron and Nitrogen by Majid Monajjemi* in Crimson Publishers: Peer Reviewed Material Science Journals
IMPROVEMENT IN MORPHOLOGICAL AND ELECTRO-MAGNETIC BEHAVIOUR OF HARD FERRITE P...Editor IJMTER
The Ni-Ir substituted strontium ferrite of Sr(Ni-Ir)xFe12-2xO19 (x = 0.02 & 0.08) were
synthesized by sol-gel auto combustion technique and characterized using X-ray diffraction (XRD),
Transmission Electron Microscopy (TEM) for morphological behaviour with electrical
characteristics using Impedance Analyzer. XRD results confirmed the formation of a single phase
M-type hexagonal unit cell of space group P63/mmc. The increase in Ni-Ir concentration increases
the lattice parameter. TEM analysis of the sample demonstrates the formation of nano-size particles
which decreases with substitution. In this paper we reported the variation of dielectric constant,
dielectric loss, tangent loss, conductivity and magnetic behaviour with composition with temperature
and frequency analysis of the sample. The migration of Fe3+ ion from octahedral to tetrahedral site
decreases the dielectric constant with increase in Ni-Ir concentration. Activation energies were
found similar with calculated at ferromagnetic and paramagnetic region. The material study we
confined that the activation energy in the paramagnetic region is higher than that in the
ferromagnetic region. The enhanced resistivity of Ni-Ir substituted strontium hexaferrites is a
prospective application in high frequency and in microwave devices development.
Microstructural and Dielectric Characterization of Sr doped Ba(Fe0.5Ta0.5)O3 ...theijes
Solid state reaction method was used to synthesize Ba1-xSrx(Fe0.5Ta0.5)O3 ceramic(x=0, 0.1, 0.2, 0.3, 0.4 and 0.5). The raw materials of making Sr doped Ba(Fe0.5Ta0.5)O3 were BaCO3, SrCO3, Fe2O3, Ta2O5 (purity better than 99%). Pellet and ring shaped samples prepared from each composition were sintered at 1400 and 1450ºC for 5 hour. The phase formation of Ba1-xSrx(Fe0.5Ta0.5)O3 was checked using X-ray diffraction (XRD) technique and observed a cubic perovskite crystal structure in space group Pm3m (221). Microstructure of the individual compound was examined by the field emission scanning electron micrograph (FESEM). Grain size was found to be varied with Sr content. The lattice parameter decreased with increasing Sr content. Dielectric spectroscopy was applied to investigate the electrical properties of BSFT at room temperature and in a frequency range of 100Hz–100 MHz. An analysis of the dielectric constant εʹ and loss tangent tan with frequency was performed assuming a distribution of relaxation times. The low frequency dielectric dispersion corresponds to the DC electrical conductivity.
Synthesis and Characterisation of Copper Oxide nanoparticlesIOSR Journals
Cupric oxide (CuO) nanoparticles were prepared by the chemical route by calcinations at a higher temperature from 300oC to 400 oC. For the comparison transmission electron microscopy (TEM) and x-ray diffraction (XRD) measurements were made through JCPDS. There is good agreement between data produced by spectroscopy and the microscopic measurements.
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.
Structural and Dielectric Studies of Cerium Substituted Nickel Ferrite Nano P...theijes
Cerium substituted Nickel ferrite nanoparticles with general formula NiCeXFe2-XO4 (x=0.0, 0.05, 0.1, 0.15) have been synthesized by using sol-gel method. The crystalline structure and grain size of these particles were analyzed by using XRD; the particle size ranged from 12.22nm to 17.60nm.The decrease in value of the lattice parameter with doping suggests that there is shrinkage in unit cell. The single-phase cubic spinal structure was clearly indicated by the XRD patterns of pure NiFe2O4.The XRD pattern also show that all the samples had formed the cubic single phase spinal structure. 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 Ce3+ in parent crystal structure.
Spectral studies of praseodymium doped heavy metal borate glass systemsinventy
Praseodymium doped HMO glasses are fabricated with the following compositions using conventional melt quenching technique. The compositions of the glass systems are 12 ZnO + 33 B2O3 + (50-x) PbO + (x+10) CaO + 4 Al2O3 + 1 Pr6O11 where (x = 0,10,20,30 and 40 mol %.). Certain physical properties of these systems have been evaluated and reported. Spectral data for all these systems were recorded for X-ray diffraction, Optical absorption and Fluorescence properties. The Judd-Ofelt intensity parameters Ωλ ( λ = 2,4,6) were evaluated from the spectral data and in turn employed to evaluate the lasing parameters of Pr3+ HMO glass systems such as radiative transition probabilities (A), radiative life-times (τR), branching ratios (βR) absorption cross-sections (σa) and Stimulated emission cross-sections (σe). The experimental and calculated branching ratios (βR) for the lasing transitions 3P0 3H4, 3P0 3H6, and 3P0 3F2 are found to be in good agreement in the present work.
Electrical transport properties of nanocrystalline and bulk nickel.pdfProximaCentauri15
In this work, the comparative study on the electrical transport properties of nanocrystalline nickel
ferrite (NiFe2O4) and its bulk counterpart has been carried out in detail by using complex impedance
spectroscopy in a wide range of frequencies (100 Hz–1 MHz) and temperatures (40 °C–320 °C). The
dispersive nature of the dielectric constant and loss factor is explained by the Maxwell-Wagner model
and Koop’s phenomenological theory. The value of the dielectric constant for nanocrystalline nickel
ferrite is found to be more as compared to its bulk counterpart. The frequency variation dielectric
permittivity is well fitted with the modified Debye formula, which suggests the presence of multiple
relaxation processes. The temperature dependent ac conductivity follows Jonscher’s universal power
law and reveals the presence of multiple transport mechanisms from small polaron hopping (SPH) to
correlated barrier hopping (CBH) mechanism near 200 °C. The estimated values of Mott parameters
are found to be satisfactory. Thermally activated relaxation phenomena have been confirmed by
scaling curves of imaginary impedance (Z) andmodulus (M). The comparison between the Z and
M spectra indicates that both long-range and short-rangemovement of charge carriers contribute to
dielectric relaxation with short-range charge carriers predominating at low temperatures while longrange
charge carriers are dominating at high temperatures. Analysis of the semicircular arcs of Nyquist
plot indicates the presence of grain boundary contribution to the electrical conduction process for the
nanocrystalline sample at high temperatures. The non-Debye type of relaxation has been examined by
stretching exponential factor (β) which has been estimated by fitting the modifiedKWW
(Kohlrausch-Williams-Watts) equation to the imaginary electric modulus curve. The value of β is
found to be strongly temperature dependent and its value for the nanocrystalline sample is less than
that of the bulk system which is explained on the basis of dipole-dipole interaction.
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.
Dielectric Behaviour of Pzt Ceramics at Microwave Frequenciestheijes
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.
Theoretical work submitted to the Journal should be original in its motivation or modeling structure. Empirical analysis should be based on a theoretical framework and should be capable of replication. It is expected that all materials required for replication (including computer programs and data sets) should be available upon request to the authors.
The International Journal of Engineering & Science would take much care in making your article published without much delay with your kind cooperation.
International Refereed Journal of Engineering and Science (IRJES)irjes
International Refereed Journal of Engineering and Science (IRJES) is a leading international journal for publication of new ideas, the state of the art research results and fundamental advances in all aspects of Engineering and Science. IRJES is a open access, peer reviewed international journal with a primary objective to provide the academic community and industry for the submission of half of original research and applications.
International Journal of Engineering and Science Invention (IJESI)inventionjournals
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
EFFECT OF ULTRAVIOLET RADIATION ON STRUCTURAL PROPERTIES OF NANOWIRESijoejournal
Copper nanowires were prepared through electrochemical template synthesis using Nucleopore polycarbonate membranes having nominal pore sizes of 800nm and 15nm diameter. The 800nm and 15nm nanowires thus grown were viewed under SEM and TEM respectively, while their FCC crystallographic structure was confirmed through X-ray and electron diffraction patterns. The X-ray diffraction peaks indicated strong texturing for (200). The texturing was found to reduce significantly upon exposure to ultraviolet radiation.
Similar to Effect of calcination on the electrical properties and quantum confinement of fe2 o3 nanoparticles (20)
Mechanical properties of hybrid fiber reinforced concrete for pavementseSAT Journals
Abstract
The effect of addition of mono fibers and hybrid fibers on the mechanical properties of concrete mixture is studied in the present
investigation. Steel fibers of 1% and polypropylene fibers 0.036% were added individually to the concrete mixture as mono fibers and
then they were added together to form a hybrid fiber reinforced concrete. Mechanical properties such as compressive, split tensile and
flexural strength were determined. The results show that hybrid fibers improve the compressive strength marginally as compared to
mono fibers. Whereas, hybridization improves split tensile strength and flexural strength noticeably.
Keywords:-Hybridization, mono fibers, steel fiber, polypropylene fiber, Improvement in mechanical properties.
Material management in construction – a case studyeSAT Journals
Abstract
The objective of the present study is to understand about all the problems occurring in the company because of improper application
of material management. In construction project operation, often there is a project cost variance in terms of the material, equipments,
manpower, subcontractor, overhead cost, and general condition. Material is the main component in construction projects. Therefore,
if the material management is not properly managed it will create a project cost variance. Project cost can be controlled by taking
corrective actions towards the cost variance. Therefore a methodology is used to diagnose and evaluate the procurement process
involved in material management and launch a continuous improvement was developed and applied. A thorough study was carried
out along with study of cases, surveys and interviews to professionals involved in this area. As a result, a methodology for diagnosis
and improvement was proposed and tested in selected projects. The results obtained show that the main problem of procurement is
related to schedule delays and lack of specified quality for the project. To prevent this situation it is often necessary to dedicate
important resources like money, personnel, time, etc. To monitor and control the process. A great potential for improvement was
detected if state of the art technologies such as, electronic mail, electronic data interchange (EDI), and analysis were applied to the
procurement process. These helped to eliminate the root causes for many types of problems that were detected.
Managing drought short term strategies in semi arid regions a case studyeSAT Journals
Abstract
Drought management needs multidisciplinary action. Interdisciplinary efforts among the experts in various fields of the droughts
prone areas are helpful to achieve tangible and permanent solution for this recurring problem. The Gulbarga district having the total
area around 16, 240 sq.km, and accounts 8.45 per cent of the Karnataka state area. The district has been situated with latitude 17º 19'
60" North and longitude of 76 º 49' 60" east. The district is situated entirely on the Deccan plateau positioned at a height of 300 to
750 m above MSL. Sub-tropical, semi-arid type is one among the drought prone districts of Karnataka State. The drought
management is very important for a district like Gulbarga. In this paper various short term strategies are discussed to mitigate the
drought condition in the district.
Keywords: Drought, South-West monsoon, Semi-Arid, Rainfall, Strategies etc.
Life cycle cost analysis of overlay for an urban road in bangaloreeSAT Journals
Abstract
Pavements are subjected to severe condition of stresses and weathering effects from the day they are constructed and opened to traffic
mainly due to its fatigue behavior and environmental effects. Therefore, pavement rehabilitation is one of the most important
components of entire road systems. This paper highlights the design of concrete pavement with added mono fibers like polypropylene,
steel and hybrid fibres for a widened portion of existing concrete pavement and various overlay alternatives for an existing
bituminous pavement in an urban road in Bangalore. Along with this, Life cycle cost analyses at these sections are done by Net
Present Value (NPV) method to identify the most feasible option. The results show that though the initial cost of construction of
concrete overlay is high, over a period of time it prove to be better than the bituminous overlay considering the whole life cycle cost.
The economic analysis also indicates that, out of the three fibre options, hybrid reinforced concrete would be economical without
compromising the performance of the pavement.
Keywords: - Fatigue, Life cycle cost analysis, Net Present Value method, Overlay, Rehabilitation
Laboratory studies of dense bituminous mixes ii with reclaimed asphalt materialseSAT Journals
Abstract
The issue of growing demand on our nation’s roadways over that past couple of decades, decreasing budgetary funds, and the need to
provide a safe, efficient, and cost effective roadway system has led to a dramatic increase in the need to rehabilitate our existing
pavements and the issue of building sustainable road infrastructure in India. With these emergency of the mentioned needs and this
are today’s burning issue and has become the purpose of the study.
In the present study, the samples of existing bituminous layer materials were collected from NH-48(Devahalli to Hassan) site.The
mixtures were designed by Marshall Method as per Asphalt institute (MS-II) at 20% and 30% Reclaimed Asphalt Pavement (RAP).
RAP material was blended with virgin aggregate such that all specimens tested for the, Dense Bituminous Macadam-II (DBM-II)
gradation as per Ministry of Roads, Transport, and Highways (MoRT&H) and cost analysis were carried out to know the economics.
Laboratory results and analysis showed the use of recycled materials showed significant variability in Marshall Stability, and the
variability increased with the increase in RAP content. The saving can be realized from utilization of recycled materials as per the
methodology, the reduction in the total cost is 19%, 30%, comparing with the virgin mixes.
Keywords: Reclaimed Asphalt Pavement, Marshall Stability, MS-II, Dense Bituminous Macadam-II
Laboratory investigation of expansive soil stabilized with natural inorganic ...eSAT Journals
Abstract
Soil stabilization has proven to be one of the oldest techniques to improve the soil properties. Literature review conducted revealed
that uses of natural inorganic stabilizers are found to be one of the best options for soil stabilization. In this regard an attempt has
been made to evaluate the influence of RBI-81 stabilizer on properties of black cotton soil through laboratory investigations. Black
cotton soil with varying percentages of RBI-81 viz., 0, 0.5, 1, 1.5, 2, and 2.5 percent were studied for moisture density relationships
and strength behaviour of soils. Also the effect of curing period was evaluated as literature review clearly emphasized the strength
gain of soils stabilized with RBI-81 over a period of time. The results obtained shows that the unconfined compressive strength of
specimens treated with RBI-81 increased approximately by 250% for a curing period of 28 days as compared to virgin soil. Further
the CBR value improved approximately by 400%. The studies indicated an increasing trend for soil strength behaviour with
increasing percentage of RBI-81 suggesting its potential applications in soil stabilization.
Influence of reinforcement on the behavior of hollow concrete block masonry p...eSAT Journals
Abstract
Reinforced masonry was developed to exploit the strength potential of masonry and to solve its lack of tensile strength. Experimental
and analytical studies have been carried out to investigate the effect of reinforcement on the behavior of hollow concrete block
masonry prisms under compression and to predict ultimate failure compressive strength. In the numerical program, three dimensional
non-linear finite elements (FE) model based on the micro-modeling approach is developed for both unreinforced and reinforced
masonry prisms using ANSYS (14.5). The proposed FE model uses multi-linear stress-strain relationships to model the non-linear
behavior of hollow concrete block, mortar, and grout. Willam-Warnke’s five parameter failure theory has been adopted to model the
failure of masonry materials. The comparison of the numerical and experimental results indicates that the FE models can successfully
capture the highly nonlinear behavior of the physical specimens and accurately predict their strength and failure mechanisms.
Keywords: Structural masonry, Hollow concrete block prism, grout, Compression failure, Finite element method,
Numerical modeling.
Influence of compaction energy on soil stabilized with chemical stabilizereSAT Journals
Abstract
Increase in traffic along with heavier magnitude of wheel loads cause rapid deterioration in pavements. There is a need to improve
density, strength of soil subgrade and other pavement layers. In this study an attempt is made to improve the properties of locally
available loamy soil using twin approaches viz., i) increasing the compaction of soil and ii) treating the soil with chemical stabilizer.
Laboratory studies are carried out on both untreated and treated soil samples compacted by different compaction efforts. Studies
show that increase in compaction effort results in increase in density of soil. However in soil treated with chemical stabilizer, rate of
increase in density is not significant. The soil treated with chemical stabilizer exhibits improvement in both strength and performance
properties.
Keywords: compaction, density, subgradestabilization, resilient modulus
Geographical information system (gis) for water resources managementeSAT Journals
Abstract
Water resources projects are inherited with overlapping and at times conflicting objectives. These projects are often of varied sizes
ranging from major projects with command areas of millions of hectares to very small projects implemented at the local level. Thus,
in all these projects there is seldom proper coordination which is essential for ensuring collective sustainability.
Integrated watershed development and management is the accepted answer but in turn requires a comprehensive framework that can
enable planning process involving all the stakeholders at different levels and scales is compulsory. Such a unified hydrological
framework is essential to evaluate the cause and effect of all the proposed actions within the drainage basins.
The present paper describes a hydrological framework developed in the form of a Hydrologic Information System (HIS) which is
intended to meet the specific information needs of the various line departments of a typical State connected with water related aspects.
The HIS consist of a hydrologic information database coupled with tools for collating primary and secondary data and tools for
analyzing and visualizing the data and information. The HIS also incorporates hydrological model base for indirect assessment of
various entities of water balance in space and time. The framework would be maintained and updated to reflect fully the most
accurate ground truth data and the infrastructure requirements for planning and management.
Keywords: Hydrological Information System (HIS); WebGIS; Data Model; Web Mapping Services
Forest type mapping of bidar forest division, karnataka using geoinformatics ...eSAT Journals
Abstract
The study demonstrate the potentiality of satellite remote sensing technique for the generation of baseline information on forest types
including tree plantation details in Bidar forest division, Karnataka covering an area of 5814.60Sq.Kms. The Total Area of Bidar
forest division is 5814Sq.Kms analysis of the satellite data in the study area reveals that about 84% of the total area is Covered by
crop land, 1.778% of the area is covered by dry deciduous forest, 1.38 % of mixed plantation, which is very threatening to the
environmental stability of the forest, future plantation site has been mapped. With the use of latest Geo-informatics technology proper
and exact condition of the trees can be observed and necessary precautions can be taken for future plantation works in an appropriate
manner
Keywords:-RS, GIS, GPS, Forest Type, Tree Plantation
Factors influencing compressive strength of geopolymer concreteeSAT Journals
Abstract
To study effects of several factors on the properties of fly ash based geopolymer concrete on the compressive strength and also the
cost comparison with the normal concrete. The test variables were molarities of sodium hydroxide(NaOH) 8M,14M and 16M, ratio of
NaOH to sodium silicate (Na2SiO3) 1, 1.5, 2 and 2.5, alkaline liquid to fly ash ratio 0.35 and 0.40 and replacement of water in
Na2SiO3 solution by 10%, 20% and 30% were used in the present study. The test results indicated that the highest compressive
strength 54 MPa was observed for 16M of NaOH, ratio of NaOH to Na2SiO3 2.5 and alkaline liquid to fly ash ratio of 0.35. Lowest
compressive strength of 27 MPa was observed for 8M of NaOH, ratio of NaOH to Na2SiO3 is 1 and alkaline liquid to fly ash ratio of
0.40. Alkaline liquid to fly ash ratio of 0.35, water replacement of 10% and 30% for 8 and 16 molarity of NaOH and has resulted in
compressive strength of 36 MPa and 20 MPa respectively. Superplasticiser dosage of 2 % by weight of fly ash has given higher
strength in all cases.
Keywords: compressive strength, alkaline liquid, fly ash
Experimental investigation on circular hollow steel columns in filled with li...eSAT Journals
Abstract
Composite Circular hollow Steel tubes with and without GFRP infill for three different grades of Light weight concrete are tested for
ultimate load capacity and axial shortening , under Cyclic loading. Steel tubes are compared for different lengths, cross sections and
thickness. Specimens were tested separately after adopting Taguchi’s L9 (Latin Squares) Orthogonal array in order to save the initial
experimental cost on number of specimens and experimental duration. Analysis was carried out using ANN (Artificial Neural
Network) technique with the assistance of Mini Tab- a statistical soft tool. Comparison for predicted, experimental & ANN output is
obtained from linear regression plots. From this research study, it can be concluded that *Cross sectional area of steel tube has most
significant effect on ultimate load carrying capacity, *as length of steel tube increased- load carrying capacity decreased & *ANN
modeling predicted acceptable results. Thus ANN tool can be utilized for predicting ultimate load carrying capacity for composite
columns.
Keywords: Light weight concrete, GFRP, Artificial Neural Network, Linear Regression, Back propagation, orthogonal
Array, Latin Squares
Experimental behavior of circular hsscfrc filled steel tubular columns under ...eSAT Journals
Abstract
This paper presents an outlook on experimental behavior and a comparison with predicted formula on the behaviour of circular
concentrically loaded self-consolidating fibre reinforced concrete filled steel tube columns (HSSCFRC). Forty-five specimens were
tested. The main parameters varied in the tests are: (1) percentage of fiber (2) tube diameter or width to wall thickness ratio (D/t
from 15 to 25) (3) L/d ratio from 2.97 to 7.04 the results from these predictions were compared with the experimental data. The
experimental results) were also validated in this study.
Keywords: Self-compacting concrete; Concrete-filled steel tube; axial load behavior; Ultimate capacity.
Evaluation of punching shear in flat slabseSAT Journals
Abstract
Flat-slab construction has been widely used in construction today because of many advantages that it offers. The basic philosophy in
the design of flat slab is to consider only gravity forces; this method ignores the effect of punching shear due to unbalanced moments
at the slab column junction which is critical. An attempt has been made to generate generalized design sheets which accounts both
punching shear due to gravity loads and unbalanced moments for cases (a) interior column; (b) edge column (bending perpendicular
to shorter edge); (c) edge column (bending parallel to shorter edge); (d) corner column. These design sheets are prepared as per
codal provisions of IS 456-2000. These design sheets will be helpful in calculating the shear reinforcement to be provided at the
critical section which is ignored in many design offices. Apart from its usefulness in evaluating punching shear and the necessary
shear reinforcement, the design sheets developed will enable the designer to fix the depth of flat slab during the initial phase of the
design.
Keywords: Flat slabs, punching shear, unbalanced moment.
Evaluation of performance of intake tower dam for recent earthquake in indiaeSAT Journals
Abstract
Intake towers are typically tall, hollow, reinforced concrete structures and form entrance to reservoir outlet works. A parametric
study on dynamic behavior of circular cylindrical towers can be carried out to study the effect of depth of submergence, wall thickness
and slenderness ratio, and also effect on tower considering dynamic analysis for time history function of different soil condition and
by Goyal and Chopra accounting interaction effects of added hydrodynamic mass of surrounding and inside water in intake tower of
dam
Key words: Hydrodynamic mass, Depth of submergence, Reservoir, Time history analysis,
Evaluation of operational efficiency of urban road network using travel time ...eSAT Journals
Abstract
Efficiency of the road network system is analyzed by travel time reliability measures. The study overlooks on an important measure of
travel time reliability and prioritizing Tiruchirappalli road network. Traffic volume and travel time were collected using license plate
matching method. Travel time measures were estimated from average travel time and 95th travel time. Effect of non-motorized vehicle
on efficiency of road system was evaluated. Relation between buffer time index and traffic volume was created. Travel time model has
been developed and travel time measure was validated. Then service quality of road sections in network were graded based on
travel time reliability measures.
Keywords: Buffer Time Index (BTI); Average Travel Time (ATT); Travel Time Reliability (TTR); Buffer Time (BT).
Estimation of surface runoff in nallur amanikere watershed using scs cn methodeSAT Journals
Abstract
The development of watershed aims at productive utilization of all the available natural resources in the entire area extending from
ridge line to stream outlet. The per capita availability of land for cultivation has been decreasing over the years. Therefore, water and
the related land resources must be developed, utilized and managed in an integrated and comprehensive manner. Remote sensing and
GIS techniques are being increasingly used for planning, management and development of natural resources. The study area, Nallur
Amanikere watershed geographically lies between 110 38’ and 110 52’ N latitude and 760 30’ and 760 50’ E longitude with an area of
415.68 Sq. km. The thematic layers such as land use/land cover and soil maps were derived from remotely sensed data and overlayed
through ArcGIS software to assign the curve number on polygon wise. The daily rainfall data of six rain gauge stations in and around
the watershed (2001-2011) was used to estimate the daily runoff from the watershed using Soil Conservation Service - Curve Number
(SCS-CN) method. The runoff estimated from the SCS-CN model was then used to know the variation of runoff potential with different
land use/land cover and with different soil conditions.
Keywords: Watershed, Nallur watershed, Surface runoff, Rainfall-Runoff, SCS-CN, Remote Sensing, GIS.
Estimation of morphometric parameters and runoff using rs & gis techniqueseSAT Journals
Abstract
Land and water are the two vital natural resources, the optimal management of these resources with minimum adverse environmental
impact are essential not only for sustainable development but also for human survival. Satellite remote sensing with geographic
information system has a pragmatic approach to map and generate spatial input layers of predicting response behavior and yield of
watershed. Hence, in the present study an attempt has been made to understand the hydrological process of the catchment at the
watershed level by drawing the inferences from moprhometric analysis and runoff. The study area chosen for the present study is
Yagachi catchment situated in Chickamaglur and Hassan district lies geographically at a longitude 75⁰52’08.77”E and
13⁰10’50.77”N latitude. It covers an area of 559.493 Sq.km. Morphometric analysis is carried out to estimate morphometric
parameters at Micro-watershed to understand the hydrological response of the catchment at the Micro-watershed level. Daily runoff
is estimated using USDA SCS curve number model for a period of 10 years from 2001 to 2010. The rainfall runoff relationship of the
study shows there is a positive correlation.
Keywords: morphometric analysis, runoff, remote sensing and GIS, SCS - method
-
Effect of variation of plastic hinge length on the results of non linear anal...eSAT Journals
Abstract The nonlinear Static procedure also well known as pushover analysis is method where in monotonically increasing loads are applied to the structure till the structure is unable to resist any further load. It is a popular tool for seismic performance evaluation of existing and new structures. In literature lot of research has been carried out on conventional pushover analysis and after knowing deficiency efforts have been made to improve it. But actual test results to verify the analytically obtained pushover results are rarely available. It has been found that some amount of variation is always expected to exist in seismic demand prediction of pushover analysis. Initial study is carried out by considering user defined hinge properties and default hinge length. Attempt is being made to assess the variation of pushover analysis results by considering user defined hinge properties and various hinge length formulations available in literature and results compared with experimentally obtained results based on test carried out on a G+2 storied RCC framed structure. For the present study two geometric models viz bare frame and rigid frame model is considered and it is found that the results of pushover analysis are very sensitive to geometric model and hinge length adopted. Keywords: Pushover analysis, Base shear, Displacement, hinge length, moment curvature analysis
Effect of use of recycled materials on indirect tensile strength of asphalt c...eSAT Journals
Abstract
Depletion of natural resources and aggregate quarries for the road construction is a serious problem to procure materials. Hence
recycling or reuse of material is beneficial. On emphasizing development in sustainable construction in the present era, recycling of
asphalt pavements is one of the effective and proven rehabilitation processes. For the laboratory investigations reclaimed asphalt
pavement (RAP) from NH-4 and crumb rubber modified binder (CRMB-55) was used. Foundry waste was used as a replacement to
conventional filler. Laboratory tests were conducted on asphalt concrete mixes with 30, 40, 50, and 60 percent replacement with RAP.
These test results were compared with conventional mixes and asphalt concrete mixes with complete binder extracted RAP
aggregates. Mix design was carried out by Marshall Method. The Marshall Tests indicated highest stability values for asphalt
concrete (AC) mixes with 60% RAP. The optimum binder content (OBC) decreased with increased in RAP in AC mixes. The Indirect
Tensile Strength (ITS) for AC mixes with RAP also was found to be higher when compared to conventional AC mixes at 300C.
Keywords: Reclaimed asphalt pavement, Foundry waste, Recycling, Marshall Stability, Indirect tensile strength.
About
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Technical Specifications
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
Key Features
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface
• Compatible with MAFI CCR system
• Copatiable with IDM8000 CCR
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
Application
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Cosmetic shop management system project report.pdfKamal Acharya
Buying new cosmetic products is difficult. It can even be scary for those who have sensitive skin and are prone to skin trouble. The information needed to alleviate this problem is on the back of each product, but it's thought to interpret those ingredient lists unless you have a background in chemistry.
Instead of buying and hoping for the best, we can use data science to help us predict which products may be good fits for us. It includes various function programs to do the above mentioned tasks.
Data file handling has been effectively used in the program.
The automated cosmetic shop management system should deal with the automation of general workflow and administration process of the shop. The main processes of the system focus on customer's request where the system is able to search the most appropriate products and deliver it to the customers. It should help the employees to quickly identify the list of cosmetic product that have reached the minimum quantity and also keep a track of expired date for each cosmetic product. It should help the employees to find the rack number in which the product is placed.It is also Faster and more efficient way.
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Final project report on grocery store management system..pdfKamal Acharya
In today’s fast-changing business environment, it’s extremely important to be able to respond to client needs in the most effective and timely manner. If your customers wish to see your business online and have instant access to your products or services.
Online Grocery Store is an e-commerce website, which retails various grocery products. This project allows viewing various products available enables registered users to purchase desired products instantly using Paytm, UPI payment processor (Instant Pay) and also can place order by using Cash on Delivery (Pay Later) option. This project provides an easy access to Administrators and Managers to view orders placed using Pay Later and Instant Pay options.
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Sachpazis:Terzaghi Bearing Capacity Estimation in simple terms with Calculati...
Effect of calcination on the electrical properties and quantum confinement of fe2 o3 nanoparticles
1. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
__________________________________________________________________________________________
Volume: 03 Issue: 03 | Mar-2014, Available @ http://www.ijret.org 570
EFFECT OF CALCINATION ON THE ELECTRICAL PROPERTIES AND
QUANTUM CONFINEMENT OF Fe2O3 NANOPARTICLES
S. I. Srikrishna Ramya1
, C. K. Mahadevan2
1
Physics Research Centre, S. T. Hindu College, M.S.University, Nagercoil - 629 002, Tamilnadu, India
2
Physics Research Centre, S. T. Hindu College, M.S.University, Nagercoil - 629 002, Tamilnadu, India
Abstract
Fe2O3 nanoparticles have been prepared by a simple solvothermal method using a domestic microwave oven. X-ray powder
diffraction measurement indicates the amorphous nature of the as-prepared sample. Calcined samples were obtained by annealing the
as-prepared sample at different temperatures, viz. 400, 500, 600 and 700o
C. Transmission electron microscopic images indicate that
all the five samples are spherical in shape. AC electrical measurements were carried out on pelletized samples by the parallel plate
capacitor method at various temperatures ranging from 40-130o
C and frequencies ranging from 100 Hz -1 MHz. Results indicate low
AC electrical conductivities and consequently show the occurrence of nano confined states. The exciton Bohr radii obtained from the
dielectric constant values at 40o
C temperature and 1 kHz frequency are 41.8, 54.8, 55.3, 56.3 and 27.0 respectively for the as-
prepared sample and samples calcined at 400, 500, 600 and 700o
C which indicate a strong quantum confinement effect. The
impedance spectra observed exhibit non-ideal behavior.
Keywords: Semiconductors, Magnetic materials, Nanoparticles, Electrical properties
----------------------------------------------------------------------***--------------------------------------------------------------------
1. INTRODUCTION
FeO, Fe2O3 and Fe3O4 are the three main types of iron oxide
nanoparticles. They are considered to be important materials
due to their biocompatibility, catalytic activity, non-toxicity,
low-cost and environmentally friendly nature. In applications
like solar energy transformation, electronics, electrochemistry,
manufacture of magnetic storage media, sorption and
purification processes and catalysis, amorphous ferric oxide
(Fe2O3) plays a key role especially because of its superior
catalytic activity, superparamagnetic behavior and the large
specific surface area of the nanoparticles [1].
The ferric oxide has four crystallographic phases, viz. -Fe2O3
(hematite), -Fe2O3, -Fe2O3 (maghemite) and -Fe2O3 [2].
Recently, we have reported [2] the preparation by a simple
route and chemical, structural, optical and magnetic
characterization of the four nanophases of Fe2O3, viz. - in the
amorphous condition (as-prepared) and - , - (slightly mixed
with - ), and - in the crystalline state. As these
nanostructured materials are also electrically important, it
becomes necessary to investigate their electrical properties.
The nanoparticles often exhibit unusual electric behaviors
different from that of their bulk counterparts owing to finite
size effects. The interest in understanding the electrical
properties of transition metal oxides is being renewed because
of their potential use in the development of novel electronic
devices. It has been discovered that nanoscaling of transition
metal oxides can have a considerable impact on their chemical
behavior, and that they can exhibit distinctive properties
including high dielectric constants, efficient charge separation
and chemical surface reactivity [3]. The dielectric properties
of a number of oxides in their films form have been
investigated for electrical applications [4-6]. Bonaedy et al [7]
have investigated the magneto-dielectric property of
polycrystalline -Fe2O3. Hasegawa et al [8] have investigated
the electrical and magnetic properties of -Fe2O3 (001)
epitaxial films. Recently, Naresh and Bhowmic [9] have
observed that both magnetic softness and electrical
conductivity increase with the decrease of grain size in the
case of -Fe1.4Ti0.6O3.
It is known that quantum confinement effects arise when the
size of the particles fall below the exciton bohr radius of the
material [10]. Also, when the particle (grain) size is smaller
than the electron mean free path, grain boundary scattering
dominates which results in dramatic changes in electrical
conductivity and polarizability, etc. [11]. The electrical
property and charge confinement effect of quantum dots
(QDs) can be accounted by the dielectric constant.
Although several reports are available on magnetic and other
properties of Fe2O3 nanoparticles, reports on electrical
properties are limited. Also, effect of calcinations on the
electrical properties has not been reported. In the present
article, we report on the AC electrical measurements carried
out on Fe2O3 nanoparticles (prepared by a simple solvothermal
method) in the frequency range 100 Hz-1 MHz and in the
temperature range 40-130o
C with emphasis on the dependence
of calcination temperature.
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2. MATERIALS AND METHODS
All the chemical reagents used are of Analytical Reagent (AR)
grade and were used without further purification. The Fe2O3
nanoparticles were prepared by the simple solvothermal
method using a domestic microwave oven reported previously
by us [2]. Ferric chloride and urea were used as the precursors
and ethylene glycol as the solvent.
X-ray powder diffraction (PXRD) measurements were carried
out using an automated diffractometer (XPERT PRO
PANalytical) with CuK radiation (=1.54056Ǻ) to
understand the crystallinity of the as-prepared sample. The as-
prepared sample was calcined at different temperatures, viz.
400, 500, 600 and 700o
C for 1h in each case in air and then
brought to room temperature naturally. Morphology and
microstructure were recorded by using a PHILIPS Technai-10
instrument for the as-prepared and three calcined (at 400, 500
and 600o
C) samples and a HITACHI H-800 TEM instrument
for the sample calcined at 700o
C.
The dielectric measurements (i.e. capacitance, Cp and
dielectric loss factor, tan δ) were made to an accuracy of + 1%
at nine different frequencies, viz. 100 Hz, 500 Hz, 1 kHz, 5
kHz, 10 kHz, 50 kHz, 100 kHz, 500 kHz and 1 MHz, and in
each case, at four different temperatures, viz.40, 70, 100 and
130o
C by the parallel plate capacitor method for the palletized
samples (hydraulically pressed with a pressure of 4 tons) using
an LCR meter (Agilent 4284 A) in a way similar to that
adopted by Mahadevan and his co-workers [11, 12]. The
dielectric parameters, viz. dielectric constant (both real and
imaginary parts, viz. ' and '' ) and AC electrical
conductivity (ζac) were determined using the measured Cp and
tan δ values.
The real and imaginary parts of the dielectric constant were
calculated using the following relations:
(1)
and
(2)
Where o is the permittivity of free space and is equal to 8.854
x10-12
F/m, d is the thickness of the pellet and A is the area of
cross-section of the pellet. The AC conductivity of the sample
was calculated using the relation:
(3)
where ω is the angular frequency (ω = 2πf where f is the
frequency of the applied AC field). The impedance
measurements (i.e. impedance, Z and phase angle) were
carried out on the pellets to an accuracy of +1% with Agilent
4284A LCR meter in the frequency range 100 Hz -1 MHz at
four different temperatures, viz. 40, 70, 100 and 130o
C in a
way similar to that adopted by Saravanan and Mahadevan
[13]. The cole-cole plots were drawn by finding the real Z (Z')
and imaginary Z (Z") values from the measured Z and phase
angle values. The exciton bohr radius (aB in nm) was
estimated by using the relation [11]:
(4)
Where r is the dielectric
constant (i.e. ' here) , me
*
and mh
*
are the effective
masses of electron and hole respectively, e is the electronic
charge and h is the Planck’s constant. We have used the '
value observed at 40o
C temperature and 1 kHz frequency and
a value of 12.5/mo (where mo is the electron rest mass) [14] for
the bracketed item in relation (4).
The porosity of the pellet was calculated using the relation:
(5)
Where D0 is the apparent density of the pellet determined by
assuming the cylindrical shape of the pellet and using the
relation:
(6)
Where m and v are mass and volume respectively of the pellet
The bulk density (Dx) was calculated using the relation:
(7)
Where Z is the number of molecules per unit cell, M is the
molecular weight, N is the Avogadro’s number and V is the
volume of the unit cell.
3. RESULTS AND DISCUSSION
Figure 1 shows the photograph of the as-prepared and calcined
samples along with the corresponding pallets. The PXRD
pattern of the as-prepared sample is shown in Figure 2. Figure
3 shows the transmission electron microscopic (TEM) images
observed. Table 1 contains the particle (grain) sizes (D)
estimated through TEM analysis (reported in [2]), the bulk
**22
2
11
4 he
r
B
mme
h
a
A
dCp
0
'
tan'''
tan' 0ac
xD
D
P 0
1
Ad
m
v
m
D 0
NV
ZM
Dx
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Volume: 03 Issue: 03 | Mar-2014, Available @ http://www.ijret.org 572
densities (Dx), pellet densities (Do) and porosity percentages
(P%).
Figure 2 indicates the nearly amorphous nature of the as-
prepared sample. The crystallographic phases of the as-
prepared and calcined samples have been identified (reported
in [2]) as : Amorphous γ-Fe2O3 (As-prepared), crystalline ε-
Fe2O3 (Calcined at 400o
C), crystalline (ε+β ) - Fe2O3
(Calcined at 500o
C), Crystalline (β+α) - Fe2O3 (Calcined at
600o
C) and crystalline α-Fe2O3 (Calcined at 700o
C). The
TEM images indicate that the nanoparticles are agglomerative
and spherical in shape. The morphology is found to be
homogeneous (see Figure 3) and the particle size increases
with the increase of calcination temperature (see Table 1).
The dielectric parameters, viz. ' , '' , tan δ and ζac are
shown in Figures 4-7. Table 2 contains the observed ' , ''
,tan δ and ζac values at 40o
C temperature and 1 kHz frequency
and the estimated aB values. Calcination dependences of ' ,
'' , tan δ and ζac are illustrated in Figures 8 and 9. The ' ,
'' ,tan δ values increase with the increase in temperature and
decrease with the increase in frequency. This nature of
variation is in agreement with that reported earlier for iron
oxide thin film [4] and for other oxide dielectric films [15].
Also, this is considered to be a normal behavior. In addition,
it is observed that the as-prepared and two calcined (at lower
temperatures, viz. 400 and 500o
C) samples (structurally - and
- based phases) exhibit very high temperature dependence of
' , '' and ζac (see Figure 8). The temperature dependences
of ' , '' and ζac are less in the case of - and -based phases.
The dielectric behavior of nanostructured materials, as per the
theory, is primarily due to different types of polarizations
present in the material [16]. The dielectric constant is
attributed to four types of polarizations [17] such as electronic,
ionic, dipolar and space charge polarizations. All these four
types of polarizations contribute at lower frequencies and
hence the ' and '' values are usually higher. Variation of '
and '' with temperature is strong in the case of space charge
and dipolar polarizations [17,18].
The nanoparticles possess enormous number of interfaces, and
the large number of defects present at these interfaces can
cause a charge distribution. When an electric field is applied
these space charges move and get trapped but these defects
result in the formation of dipole moments. Interfaces in
nanocrystals possess many oxygen ion vacancies [2] which are
equivalent to positive charges giving dipole moments. When
exposed to an electric field these dipoles rotate giving a
resultant dipole moment in the direction of the applied field
[19]. The space charge and dipolar polarizations occur upto
frequencies of around 1 kHz only. Thus, the higher dielectric
constant values observed at lower frequencies can be
attributed mainly to the space charge and dipolar polarizations
[20]. As the temperature increases more and more dipoles will
be oriented resulting in an increase in the dipole moment value
[21]. The increase of dielectric constant value with the
increase of temperature observed in the present study can be
explained as due to the above reason. Ionic polarization is
expected to exist up to a frequency of 100 kHz. Beyond 100
kHz frequency, only electronic polarization can exist. The
decrease of dielectric constant value with the increase of
frequency observed in the present study can be explained as
due to this.
The ' values observed at 40o
C temperature and 1kHz
frequency are significantly less than the standard dielectric
constant value (14.2) for iron oxide and that observed for thin
film (12.5) [4]. This indicates that the polarization mechanism
in the nanophases considered is mainly due to the space
charge polarization and consequently indicates the occurrence
of nanoconfined states which may substantially contribute to
the electrical properties. In nanophases, the excitonic size
becomes comparable or even larger than the particle which
results in splitting of the energy bands into discrete
quantization levels. The low D/aB ratios indicate a strong
quantum confinement effect [11].
The ζac values observed in the present study for all the five
samples are very small (i.e. the resistances are very large). α-
Fe2O3, generally, has a conductivity of 10-1
- 10-4
mho/m and
it increases for samples doped with other metal ions [22-24].
Leygraf et al [25] have reported a conductivity of 1-10 mho/m
for a Mg-doped iron oxide cathode. The electrical
conductivity at room temperature for iron oxide thin film is
found to be in the order of 10-2
mho/m [4,26]. Hasegawa et al
[8] have observed at room temperature a conductivity of ~ 1
mho/m for the -Fe2O3 epitaxial films. The ζac values
observed in the present study are comparable to the DC
conductivity of 10-6
mho/m observed [27] at room temperature
for nanocrystalline -Fe2O3 powder with average particle size
35 nm. The low ζac values observed for the nanoparticles
(with low particle sizes) indicate that the charge transport
process is mainly due to the grain boundary scattering [28].
The electrical conductivity of nanoparticles is lower than that
of both conventional coarse grained polycrystalline material
and alloys. In composites, the magnitude of electrical
conductivity can be changed by altering the size of the
electrically conducting component. It appears to be that the
particle size also plays a crucial role in the AC conductivity.
It is generally accepted that smaller the particle sizes higher
the lattice defects. Some reports suggest that lattice defects
form acceptor- or donor-like levels in the forbidden energy
gap and act as trapping centres for charge carriers which affect
the electrical behavior [29]. The ζac value, in the present
study, increases with the increase in temperature but does not
vary systematically with frequency especially at higher
temperatures. This may be due to the randomness in the grain
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Volume: 03 Issue: 03 | Mar-2014, Available @ http://www.ijret.org 573
boundary scattering and trapping of charge carriers especially
at higher temperatures.
The electrical charges migrate under the influence of the
applied electrical field that contributes to the electrical
response of the system. The conductivity is an increasing
function of frequency in the case of conduction of hopping
and is a decreasing function of frequency in the case of band
conduction (drift of electric charge carriers). The total
conductivity (depending on the absolute temperature, T) can
be considered as the summation of both the band and hopping
parts represented by the relation:
tot = (T) + (, T) (8)
The first term is due to the band conduction and frequency
independent that can be considered as the DC conductivity
[30-32]. The second term is due to the hopping process and is
frequency dependent that can be considered as the AC
conductivity
The AC conductivity is expected to obey the empirical
formula of the frequency dependence given by the AC power
Law [32]:
(, T) = ac = Bn
(9)
Here, B and n are constants which depend on the both
temperature and compositions; n is dimension less virus B has
the electrical conductivity units (mho/m). The logarithmic
representation of equation (9) can be written as;
lnac = lnB+ n(ln) (10)
The values of n and B can be determined by plotting lnac
against ln.
In the presence study, the ac values were calculated using
relation (3) depending on dielectric measurement. Figure (8)
shows the ac versus ln drawn using the calculated ac
values. Equation (9) shows increasing AC conductivity with
the increasing frequency. However, this behavior is not seen at
high temperatures (see Figures 7 and 10) . This indicates that
the normal semiconducting behavior is exhibited at low
temperatures for the samples considered in the present study.
It is understood that the value of n ranges between 0 and 1.
When n=0, the electrical conduction is frequency independent
or DC conduction, but for n 1, the conduction is frequency
dependent or AC conduction [30]. The n and B values were
determined by best fitting the lnac versus ln lines using the
least squares principles. n value ranges from 0.13 to 0.67
which suggests that the conduction phenomenon in the studied
samples is AC conduction due to hopping of charges. Fig 11
shows the temperature dependence of B values. As B is the
conductivity value when the frequency of the applied field is
zero, this may be treated as the DC conductivity, dc.
It is found that the temperature dependence of dc is higher for
the As-prepared, calcined at 400o
C and calcined at 500o
C
samples as in the case of AC conductivity. The dc values are
significantly less than ac values as expected.
The cole-cole plots (see Figure 12) illustrate the non-ideal
behavior (i.e. departure from a single arc centred on the real
axis of Z, Z'-axis). The non-ideal behavior exhibited by the
impedance spectra can be explained as due to the presence of a
high degree of defects [33] such as oxygen vacancies [2]
present in the grain boundaries.
The ' values at 1 kHz frequency and 130o
C temperature are
4199, 2939 and 4809 respectively for the as-prepared and
calcined at 400o
C and 500o
C samples. This very high
temperature dependence of ' indicates that these
nanoparticles can be expected to be useful for high
temperature capacitor applications.
4. CONCLUSIONS
Fe2O3 nanoparticles have been prepared with spherical shape
and amorphous nature by a simple solvothermal method. The
as-prepared and calcined (at 400, 500 600 and 700o
C) samples
have been structurally and electrically characterized by TEM
analysis and dielectric measurements. TEM images indicate
the spherical shape. Results of dielectric measurements
indicate a strong quantum confinement effect. The non-ideal
behavior exhibited by the impedance spectra could be
explained as due to the oxygen vacancies present in the grain
boundaries. The increase of calcinations temperature does not
influence the electrical properties in a systematic way as the
properties are crystal structure dependent. The very high
temperature dependence of r observed for the as-prepared and
calcined at 400 and 500o
C samples indicate that they can be
expected to be useful for high temperature capacitor
applications.
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FIGURES
Fig 1: Photograph of samples with pellets : (a) As-prepared, (b) Calcined at 400o
C, (c) Calcined at 500o
C, (d) Calcined at
600o
C and (e) Calcined at 700o
C
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Fig 2: PXRD pattern of the as-prepared sample
Fig 3: TEM images : (a) As-prepared, (b) Calcined at 400o
C, (c) Calcined at 500o
C, (d) Calcined at 600o
C and (e)
Calcined at 700o
C
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Volume: 03 Issue: 03 | Mar-2014, Available @ http://www.ijret.org 576
Fig 4: The real parts of dielectric constants (ε’) : (a) As-prepared, (b) Calcined at 400o
C, (c) Calcined at 500o
C, (d)
Calcined at 600o
C and (e) Calcined at 700o
C [Unseen plots are shown in insets]
Fig 5: The imaginary parts of dielectric constants (ε’’) : (a) As-prepared, (b) Calcined at 400o
C, (c) Calcined at 500o
C, (d)
Calcined at 600o
C and (e) Calcined at 700o
C [Unseen plots are shown in insets]
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Fig 6: The dielectric loss factors (tan δ) : (a) As-prepared, (b) Calcined at 400o
C, (c) Calcined at 500o
C, (d) Calcined at
600o
C and (e) Calcined at 700o
C
Fig 7: The AC electrical conductivities (x 10-5
mho m-1
) (ζac) : (a) As-prepared, (b) Calcined at 400o
C, (c) Calcined at
500o
C, (d) Calcined at 600o
C and (e) Calcined at 700o
C [Unseen plots are shown in insets]
9. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
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Fig 8: Calcination dependence of of ε’ (a), ε’’ (b), tan δ (c), and ζac (d) for 1 KHz frequency at various temperatures [Unseen plots
are shown in insets]
Fig 9: Calcination dependence of ε’ (a), ε’’ (b), tan δ (c), and ζac (d) at 40o
C temperature for various frequencies
10. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
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Volume: 03 Issue: 03 | Mar-2014, Available @ http://www.ijret.org 579
Fig 10: The ln ζac vs ln ω plots
Fig 11: The estimated DC electrical conductivties ( x 10-7
mho m-1
) (ζdc = B)
11. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
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Volume: 03 Issue: 03 | Mar-2014, Available @ http://www.ijret.org 580
Fig 12: The cole-cole plots : (a) As-prepared, (b) Calcined at 400o
C, (c) Calcined at 500o
C, (d) Calcined at 600o
C and (e)
Calcined at 700o
C [Unseen plots are shown in insets]
Table 1: Grain sizes (D) , bulk densities (Dx) and densities (Do)and porosities of pellets
Fe2O3 sample Identified
nanophase
D (nm) Dx
(g/cc)
Do
(g/cc)
Porosity
(%)
As-prepared γ 19 4.890 1.783 63.50
Calcined at 400o
C ε 24 5.022 1.649 67.16
Calcined at 500o
C ε + β 27 5.071 1.684 66.78
Calcined at 600o
C β + α 29 5.120 1.833 64.19
Calcined at 700o
C α 33 5.270 2.328 55.82
12. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
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Volume: 03 Issue: 03 | Mar-2014, Available @ http://www.ijret.org 581
Table 2: ε', ε'', tan δ, and ζac values for 1 kHz frequency, and ζdc values at 40o
C h and estimated aB , and D/aB values
Fe2O3 sample Identified
nanophase
ε' ε'' tan δ ζac
( x 10-5
mho/m)
ζdc
( x 10-7
mho/m)
aB
(nm)
D/aB
As-prepared γ 6.919 4.869 0.704 0.027 0.020 41.8 0.307
Calcined at 400o
C ε 9.214 13.483 1.463 0.075 0.225 54.8 0.438
Calcined at 500o
C ε + β 9.292 12.271 1.321 0.068 0.319 55.3 0.488
Calcined at 600o
C β + α 9.456 8.350 0.883 0.077 0.179 56.3 0.515
Calcined at 700o
C α 4.536 4.242 0.935 0.034 0.096 27.0 1.222