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Electrical Conduction in Ceramic by Complex Impedance/Modulus Spectroscopy  [cached]
Ansu Kumar Roy,Kamal Prasad,Ashutosh Prasad
ISRN Ceramics , 2013, DOI: 10.1155/2013/369670
Study of the La0.2235 Pr0.2235 Nd0.2235 Sr0.33 MnO3 ceramic by X ray diffraction and impedance spectroscopy  [cached]
Rhouma F. I. H.,Dhahri A.,Farhat N.,Dhahri J.
EPJ Web of Conferences , 2012, DOI: 10.1051/epjconf/20122900023
Abstract: The La0.2235 Pr0.2235 Nd0.2235 Sr0.33 MnO3 (LPNSM) ceramic has been obtained from oxides by sintering in air. The electrical properties of this material have been studied using ac impedance spectroscopy technique over a wide range of temperatures and frequency. Furthermore, a detailed analysis of the impedance spectrum suggested that the electrical properties of the material are strongly temperature dependent and have a good correlation with the sample microstructure in different temperature ranges.
Modelization of the Impedance Spectroscopy of composites by Electrical Networks  [PDF]
Lotfi Zekri,Nouredine Zekri,Jean-Pierre Clerc
Physics , 2002,
Abstract: We examined in this work the effect of the inter-grains distributions as well as the scaling of the complex impedance in order to analyze its frequency dependance for composite metal-insulator films. The dependance of the characteristic frequencies on the inter-grain distribution is shown for large sample sizes. The impedance spectra become statistically stable above sizes of the order 200x200.
Measurement of Fresh Tea Leaf Growth Using Electrical Impedance Spectroscopy
Yuzo Mizukami,Kengo Yamada,Yusuke Sawai,Yuichi Yamaguchi
Agricultural Journal , 2013,
Abstract: Electrical Impedance Spectroscopy (EIS) was applied to identify EIS parameters for the growth assessment of fresh tea leaves. We compared the EIS parameters of a distributed model with the dry matter content, which is a commonly applied parameter for growth assessment. As growth progresses, EIS parameters such as the relaxation time, resistances (except intercellular resistance) and dry matter content increased. According to the results of multiple linear regression analysis of the response surface model using fifty samples, the relaxation time displayed a good correlation with the dry matter content; however, the other parameters had no significant correlation. We concluded that the relaxation time would be useful for the growth assessment of tea leaves.
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.
Method for Flow Measurement in Microfluidic Channels Based on Electrical Impedance Spectroscopy  [PDF]
Nima Arjmandi,Chengxun Liu,Willem Van Roy,Liesbet Lagae,Gustaaf Borghs
Physics , 2012, DOI: 10.1007/s10404-011-0843-0
Abstract: We have developed and characterized two novel micro flow sensors based on measuring the electrical impedance of the interface between the flowing liquid and metallic electrodes embedded on the channel walls. These flow sensors are very simple to fabricate and use, are extremely compact and can easily be integrated into most microfluidic systems. One of these devices is a micropore with two tantalum/platinum electrodes on its edges; the other is a micro channel with two tantalum /platinum electrodes placed perpendicular to the channel on its walls. In both sensors the flow rate is measured via the electrical impedance between the two metallic electrodes, which is the impedance of two metal-liquid junctions in series. The dependency of the metal-liquid junction impedance on the flow rate of the liquid has been studied. The effects of different parameters on the sensor's outputs and its noise behavior are investigated. Design guidelines are extracted and applied to achieve highly sensitive micro flow sensors with low noise.
Electrical Structure of Biological Cells and Tissues: impedance spectroscopy, stereology, and singular perturbation theory  [PDF]
Robert Eisenberg
Quantitative Biology , 2015,
Abstract: Impedance Spectroscopy resolves electrical properties into uncorrelated variables, as a function of frequency, with exquisite resolution. Separation is robust and most useful when the system is linear. Impedance spectroscopy combined with appropriate structural knowledge provides insight into pathways for current flow, with more success than other methods. Biological applications of impedance spectroscopy are often not useful since so much of biology is strongly nonlinear in its essential features, and impedance spectroscopy is fundamentally a linear analysis. All cells and tissues have cell membranes and its capacitance is both linear and important to cell function. Measurements proved straightforward in skeletal muscle, cardiac muscle, and lens of the eye. In skeletal muscle, measurements provided the best estimates of the predominant (cell) membrane system that dominates electrical properties. In cardiac muscle, measurements showed definitively that classical microelectrode voltage clamp could not control the potential of the predominant membranes, that were in the tubular system separated from the extracellular space by substantial distributed resistance. In the lens of the eye, impedance spectroscopy changed the basis of all recording and interpretation of electrical measurements and laid the basis for Rae and Mathias extensive later experimental work. Many tissues are riddled with extracellular space as clefts and tubules, for example, cardiac muscle, the lens of the eye, most epithelia, and of course frog muscle. These tissues are best analyzed with a bidomain theory that arose from the work on electrical structure described here. There has been a great deal of work since then on the bi-domain and this represents the most important contribution to biology of the analysis of electrical structure in my view.
Estimating electrical properties and the thickness of skin with electrical impedance spectroscopy: Mathematical analysis and measurements  [cached]
Ulrik Hans Birgersson,Erik Birgersson,Stig Ollmar
Journal of Electrical Bioimpedance , 2012, DOI: 10.5617/jeb.400
Abstract: Electrical impedance spectroscopy (EIS) allows for the study and characterization of tissue alterations and properties associated with the skin. Here, the potential application of EIS to estimate the thickness of the stratum corneum is explored in the form of a mathematical model for EIS, which is analyzed in the limit of 1 kHz and closed-form analytical solutions secured. These analytical expressions are verified with the numerical solution of the full set of equations and validated with an EIS study comprising 120 subjects: overall, good agreement is found in the frequency range 1-100 kHz. Combining the closed-form expression for the thickness of the stratum corneum predicted by the model with the experimental EIS measurements, a distribution for the stratum corneum thickness of the subjects is found with a mean and standard deviation that agree well with reported stratum corneum thicknesses from other experimental techniques. This, in turn, suggests that EIS could be employed to measure the thickness of the stratum corneum with reasonable accuracy. In addition, the electrical properties relevant to EIS conductivity and relative permittivity of the stratum corneum can be estimated with the closed form expressions.
Electrical impedance spectroscopy-based nondestructive testing for imaging defects in concrete structures  [PDF]
Habib Ammari,Jin Keun Seo,Tingting Zhang,Liangdong Zhou
Mathematics , 2014,
Abstract: An electrical impedance spectroscopy-based nondestructive testing (NDT) method is proposed to image both cracks and reinforcing bars in concrete structures. The method utilizes the frequency-dependent behavior of thin insulating cracks: low-frequency electrical currents are blocked by insulating cracks, whereas high-frequency currents can pass through the conducting bars without being blocked by thin cracks. Rigorous mathematical analysis relates the geometric structures of the cracks and bars to the frequency-dependent Neumann-to-Dirichlet data. Various numerical simulations support the feasibility of the proposed method.
Microcontroller-Based Sinusoidal Voltage Generation for Electrical Bio-Impedance Spectroscopy Applications  [PDF]
Juan A. Castro, A. Olmo, Pablo Pérez, A. Yúfera
Journal of Computer and Communications (JCC) , 2016, DOI: 10.4236/jcc.2016.417003
Abstract: A sinusoidal voltage wave generator is proposed based on the use of micro-processor digital signals with programmable duty-cycles, with application to real-time Electrical Cell-substrate Impedance Spectroscopy (ECIS) assays in cell cultures. The working principle relies on the time convolution of the programmed microcontroller (μC) digital signals. The expected frequency is easily tuned on the bio-impedance spectroscopy range [100 Hz, 1 MHz] thanks to the μC clock frequency selection. This system has been simulated and tested on the 8 bits μC ArduinoTM Uno with ATmega328 version. Results obtained prove that only three digital signals are required to fit the general specification in ECIS experiments, below 1% THD accuracy, and show the appropriateness of the system for the real-time monitoring of this type of biological experiments.
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