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Characterization of Electrical Behavior of Ba5HoTi3V7O30 Ceramic Using Impedance Analysis  [PDF]
Kiran Kathayat, Anuradha Panigrahi, Arvind Pandey, Susmita Kar
Materials Sciences and Applications (MSA) , 2012, DOI: 10.4236/msa.2012.36056
Abstract: Polycrystalline sample of Ba5HoTi3V7O30 was prepared using solid-state reaction technique. X-ray structural analysis indicated a single-phase formation with orthorhombic structure. Microstructural study by SEM showed non-uniform distribution of grains over the surface of the sample. Impedance and modulus spectroscopy studies were carried out, as functions of frequency (42 Hz - 5 MHz) and temperature (RT-773K). The Nyquist plots clearly showed the presence of both bulk and grain boundary effect in the compound. Electrical phenomena in the material can appropriately be modeled in terms of an equivalent circuit with R, C and CPE in parallel. The fitting procedure used here allows us to determine the value of R and C with good precision. Here R2 and R3 correspond to the resistance contributed from the grain boundary and bulk, respectively. C1 and C2 correspond to the capacitance contributed from the grain boundary and bulk, respectively. The real part of electrical modulus shows that the material is highly capacitive. The asymmetric peak of the imaginary part of electric modulus M″, predicts a non Debye type relaxation. The activation energy of the compound (calculated both from impedance and modulus spectrum) is same, and hence the relaxation process may be attributed to the same type of charge carriers.
Electrical characterization by impedance spectroscopy of Zn7Sb2O12 ceramic
Nobre, Marcos A. de Lima;Lanfredi, Silvania;
Materials Research , 2003, DOI: 10.1590/S1516-14392003000200007
Abstract: impedance spectroscopy technique was used to investigate the electric properties of zn7sb2o12, an electroceramic with inverse spinel type structure. the electric characterization of the zn7sb2o12 semiconducting ceramic was performed at temperature from 250 to 550 °c, in the frequency range from 5 hz to 13 mhz. zinc antimoniate phase was synthesized by the polymeric precursors method. the bulk resistance curve as a function of temperature exhibits a thermistor behavior with negative temperature coefficient. the bulk conductivity follows the arrhenius law with two linear branches of different slopes positioned at around a region of transition, 450 °c > t > 350 °c. the activation energy values at low temperature (< 350 °c) and high temperature (> 450 °c) are equals to 0.78 and 0.61 ev, respectively. the existence of a phase transition limiting these regions is discussed.
Electrical characterization by impedance spectroscopy of Zn7Sb2O12 ceramic
Nobre Marcos A. de Lima,Lanfredi Silvania
Materials Research , 2003,
Abstract: Impedance spectroscopy technique was used to investigate the electric properties of Zn7Sb2O12, an electroceramic with inverse spinel type structure. The electric characterization of the Zn7Sb2O12 semiconducting ceramic was performed at temperature from 250 to 550 degreesC, in the frequency range from 5 Hz to 13 MHz. Zinc antimoniate phase was synthesized by the polymeric precursors method. The bulk resistance curve as a function of temperature exhibits a thermistor behavior with negative temperature coefficient. The bulk conductivity follows the Arrhenius law with two linear branches of different slopes positioned at around a region of transition, 450 degreesC > T > 350 degreesC. The activation energy values at low temperature (< 350 degreesC) and high temperature (> 450 degreesC) are equals to 0.78 and 0.61 eV, respectively. The existence of a phase transition limiting these regions is discussed.
Structural and Electrical Characterization of Sintered Silicon Nitride Ceramic  [PDF]
Imran Khan, M. Zulfequar
Materials Sciences and Applications (MSA) , 2011, DOI: 10.4236/msa.2011.27102
Abstract: The electrical conduction phenomena, dielectric response and microstructure have been discussed in sintered silicon nitride ceramics at different temperature and frequencies. Microstructure and phase of the sintered samples was investigated by Scanning Electron Microscope (SEM) and X-ray diffractometer (XRD). The electrical conductivity, dielectric constant and dielectric loss increases exponentially with temperature greater than 600 K. The dielectric constant and loss have been measured in the frequency range 100 Hz to 1 MHz. The a.c. conduction studies in the audio frequency range 500 Hz to 1 MHz indicates that the conduction may be due to the electronic hopping mechanism. Silicon Nitride ceramics became dense after sintering. The effect of grain size and role of phase on electrical and dielectric properties have been discussed. These types of samples can be used as a high temperature semi conducting materials for device packaging.
Characterization of Physiological Glucose Concentration Using Electrical Impedance Spectroscopy  [PDF]
Quazi Delwar Hossain,Sagar Kumar Dhar
International Journal of Computer Science Issues , 2013,
Abstract: Non-invasive glucose monitoring is crucial for effective diabetes mellitus treatment while a sound correlation of a non-invasive parameter to glucose level variation is quite challenging. This paper presents characterization of glucose concentrations using Electrical Impedance Spectroscopy (EIS) in three different solutions: 1) 0.9% NaCl, 2) Saline (NaCl 1.3gm, KCl 0.75gm, Na3C6H5O7 1.45gm, D-glucose 6.75gm in 500mL) and 3) Human Blood for every 25mg/dl change of glucose in total 150ml solution. A rectangular current pulse of 1.5s duration with 1mA peak is applied to the solutions and corresponding voltage is acquired across the solutions with Agilent InfiniiVision 7000B Series oscilloscope and Matlab R2011a Instrument Control Toolbox. The circuit proposed for current injection and voltage acquisition requires only two electrodes would reduce electrode polarization and skin irritation greatly which is a major concern in many previous works use generally four electrodes. Experimental results show sound correlation between EIS and blood glucose concentration. It is clearly found from the EIS that the DC impedance of solutions increases linearly with the increment in glucose concentrations.
Electrical characterization and impedance response of lanthanum doped barium titanate ceramics
Man?i? D.,Paunovi? V.,Vijatovi? M.,Stojanovi? B.
Science of Sintering , 2008, DOI: 10.2298/sos0803283m
Abstract: The dielectric permittivity and dissipation factor of La-doped and undoped BaTiO3 were investigated as a function of frequency and temperature. The impedance response was used to study the electrical properties of La-doped BaTiO3 over the temperature range from room temperature (RT) to 350°C. La-doped and undoped BaTiO3, obtained by a modified Pechini method, were sintered in air at 1300°C for 2 and 16 hours. The impedance spectra were analyzed in terms of equivalent circuits involving resistors, capacitors and constant phase elements (CPE). The most suitable electrical circuit for the interpretation of experimental results is found to be the equivalent circuit consisting of resistors and CPE elements which replace the capacitor elements. The contribution of grain boundary resistance to the total resistance of a system is remarkable at low temperature. Dielectric permittivity of doped BaTiO3 was in the range of 8000 to 12000 at 1 kHz and the dissipation factor was less than 1%.
Characterization of the Muscle Electrical Properties in Low Back Pain Patients by Electrical Impedance Myography  [PDF]
Congo Tak-Shing Ching, Yueh-Chi Chen, Li-Hua Lu, Peiyuan F. Hsieh, Chin-Sung Hsiao, Tai-Ping Sun, Hsiu-Li Shieh, Kang-Ming Chang
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0061639
Abstract: Objectives This study aims to investigate the electrical properties of lumbar paraspinal muscles (LPM) of patients with acute lower back pain (LBP) and to study a new approach, namely Electrical Impedance Myography (EIM), for reliable, low-cost, non-invasive, and real-time assessment of muscle-strained acute LBP. Design Patients with muscle-strained acute LBP (n = 30) are compared to a healthy reference group (n = 30). Electrical properties of LPM are studied. Background EIM is a novel technique under development for the assessment of neuromuscular disease. Therefore, it is speculated that EIM can be employed for the assessment of muscle-strained acute LBP. Methods Surface electrodes, in 2-electrode configurations, was used to measure the electrical properties of patient's and healthy subject's LPM at six different frequencies (0.02, 25.02, 50.02, 1000.02, 3000.02, and 5000.02 kHz), with the amplitude of the applied voltage limited to 200 mV. Parameters of impedance (Z), extracellular resistance (Re), intracellular resistance (Ri), and the ratio of extracellular resistance to intracellular resistance (Re/Ri) of LBP patient's and healthy subject's LPM were assessed to see if significant difference in values obtained in muscle-strained acute LBP patients existed. Results Intraclass correlation coefficient (ICC) showed that all measurements (ICC>0.96 for all studying parameters: Z, Re, Ri, and Re/Ri) had good reliability and validity. Significant differences were found on Z between LBP patient's and healthy subject's LPM at all studying frequencies, with p<0.05 for all frequencies. It was also found that Re (p<0.05) and Re/Ri (p<0.05) of LBP patient's LPM was significant smaller than that of healthy subjects while Ri (p<0.05) of LBP patient's LPM was significant greater than that of healthy subjects. No statistical significant difference was found between the left and right LPM of LBP patients and healthy subjects on the four studying parameters. Conclusion EIM is a promising technique for assessing muscle-strained acute LBP.
Zn x-1Cu xMn2O4 Spinels; Synthesis, Structural Characterization and Electrical Evaluation
Méndez-Martínez, Francisco;González, Federico;Lima, Enrique;Bosch, Pedro;Pfeiffer, Heriberto;
Journal of the Mexican Chemical Society , 2010,
Abstract: this work presents the structural characterization and electrical evaluation of znx-1cuxmn2o4 spinels, which are materials presented as secondary phases into the varistor ceramic systems. samples were analyzed by x-ray diffraction, solid-state nuclear magnetic resonance, infrared spectroscopy, scanning electron microscopy and impedance spectroscopy. although, the addition of copper to the znmn2o4 spinel did not produce morphological changes, the structure and electrical behaviors changed considerably. structurally, copper addition induced the formation of partial inverse spinels, and its addition increases significantly the electrical conductivity. therefore, the formation of znx-1cuxmn2o4 spinels, as secondary phases into the varistor materials, may compromise significantly the varistor efficiency.
A New Characterization Approach of Weld Nugget Growth by Real-Time Input Electrical Impedance  [PDF]
Yoke-Rung Wong, Xin Pang
Engineering (ENG) , 2014, DOI: 10.4236/eng.2014.69054
Abstract:

The in-process changes of weld nugget growth during the Resistance Spot Welding were investigated based on the resistance of input electrical impedance. To compute the time varying resistance of input electrical impedance, the welding voltage and current signals are measured simultaneously and then converted into complex-valued signals by using Hilbert transform. Comparing with the dynamic contact resistance as reported in literature, it showed that the time varying resistance of input electrical impedance can be accurately correlated with the physical changes of weld nugget growth. Therefore, it can be used to characterize the in-process changes of weld nugget growth. Several new findings were reported based on the investigation of spot welds under no weld, with and without weld expulsion conditions.

First characterization of a new method for numerically solving the Dirichlet problem of the two-dimensional Electrical Impedance Equation  [PDF]
M. P. Ramirez T.,C. M. A. Robles G.,R. A. Hernandez-Becerril
Mathematics , 2012,
Abstract: Based upon elements of the modern Pseudoanalytic Function Theory, we analyse a new method for numerically approaching the solution of the Dirichlet boundary value problem, corresponding to the two-dimensional Electrical Impedance Equation. The analysis is performed by interpolating piecewise separable-variables conductivity functions, that are eventually used in the numerical calculations in order to obtain finite sets of orthonormal functions, whose linear combinations succeed to approach the imposed boundary conditions. To warrant the effectiveness of the numerical method, we study six different examples of conductivity. The boundary condition for every case is selected considering one exact solution of the Electrical Impedance Equation. The work intends to discuss the contributions of these results into the field of the Electrical Impedance Tomography.
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