Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 20 for “"complex impedance"”.
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Development of an electrical impedance tomograph for complex impedance imaging
… project concerns the development of electrical impedance tomography towards the production of complex impedance images. The prime intention was to investigate the feasibility of developing suitable instrumentation; but not clinical applications. It was aimed to develop techniques for the …
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Grain boundary modifications of manganese ferrite
Complex impedance spectroscopy of Mn ferrite with $\le$1.0 wt% SiO$\sb2$ and CaCO$\sb3$ additions, cooled in air, showed two distinct arcs which were attributed to bulk and grain boundary phenomena. The bulk component was invariant while the grain boundary component varied by less than two orders …
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Electrical impedance of methane flat flame
… work was undertaken to determine if electrical impedance measurements of the flame are a direct indication of fuel/air ratio. Previous worked measured electrical resistance of the combustion of gases in an atmospheric combustor. From this work, it was conjectured that the complex impedance might …
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A Microfabricated Bioimpedance Sensor with Enhanced Sensitivity for Early Breast Cancer Detection
Bioimpedance is the term given to the complex impedance value that is characteristic of the resistance that biological cells offer to the flow of electric current. The objective of this study is to analyze the differences in the bioimpedance of highly metastatic MDA-MB-231 and normal MCF 10A breast …
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Electronic digital materials
… to make any passive electronic component and complex impedance circuitry, including antennas and matching networks. Finally, with four semiconducting part-types I suggest that it is possible to assemble active components like diodes and transistors. This work details the part production …
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Electrical transport properties of barium titanate-based capacitor ceramics
… behavior were attributed to surface effects. Complex impedance spectroscopy proved to be a useful technique in separating grain, grain boundary, and contact contributions to the total impedance. Impedance plots for X7R ceramic revealed negligible contact impedance. The most probable electrical …
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Investigation into the use of active frequency selective surfaces to extend the absorption bandwidth of a conventional Salisbury screen absorber
… was thus to investigate the use of adaptive complex impedance structures, in the form of active frequency selective surfaces (AFSSs), to extend the absorption bandwidth of a small thickness Salisbury screen absorber, thus addressing directly the aforementioned by minimizing the trade-off that …
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Wideband characterization of thick film inductors
… the information contained in both waveforms the complex impedance Z(jω) of the sample can be calculated. This information is used for modeling the inductor by fitting the data to a network model. This thesis also presents a technique for the modeling and the characterization of multilayer thick …
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Characterization and modeling of magnetic materials and structures
… waveforms. From the information contained, the complex impedance of the structure under study can be calculated. This information is used for modeling that structure by fitting the data to the network model using the computer network analysis program. Experimental and simulated response …
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Electrical characterization of ferroelectric capacitors for non-volatile memory applications
… applications. Finally, the AC conductivity (complex impedance) characterization method, introduced here for the first time for ferroelectric capacitors, permits further understanding of the charge transport mechanism of ferroelectric materials. However, this characterization method is not …
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Scalable Acceleration of The Characteristic Mode Analysis Computational Toolbox Using Big Data Techniques
… by analyzing its Method of Moments (MoM) complex impedance matrix at every frequency. Depending on the size or the complexity of the target, its MoM impedance matrix can be large, containing tens of thousands of rows and columns. Therefore if hundreds of frequencies are needed to …
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Frequency dependent impedance of stranded conductors using the subdivision method
… resistances and inductances are placed into a complex impedance matrix which is then reduced through mathematical manipulations to obtain a single complex number that represents the equivalent resistance and inductance of the whole conductor. The advantage of this method is that it …
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Sculptured computational objects with smart and active computing materials
… diverse electrodes, an empirical model of complex impedance sensing, and a definition of and test for the machine sewability and flexibility of yarns. These contributions are presented in three sections: 1) the supporting arguments, and philosophy of materiality and computation behind this …
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Monitoring of Biodiesel Transesterification Process Using Impedance Measurement
… process monitoring using low frequency (15kHz) impedance sensing which is able to provide information regarding the progress of mass transfer and chemical reaction during biodiesel production. An interdigitated (ID) sensor has been used to monitoring the biodiesel process The ID sensor is of …
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Material property extraction procedure for electromomentum coupled metamaterials
… Eμ coupling of a sample using a water-filled impedance tube. The impedance tube measurement procedure presented in this work is a generalization of existing methods used to infer the frequency-dependent material properties of a sample from measurements of its scattering coefficients and …
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Using electrical stimulation responses to understand cochlear implant status
… can lead to residual hearing loss. I show that complex impedance can be used to track fibrosis formation over time by measuring electrochemical impedance spectroscopy (EIS) and voltage waveforms. Within the proposed circuit model in this chapter, the changes over time in this model can be …
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Mixed-Signal IC design for Heterogeneously Integrated Multi-Analyte Chemical Sensor Arrays
… that demonstrate a variation of resistance (or impedance) in the presence of chemical agents. For this thesis, the sensor can be either a chemoresistive bead or a nanowire. By integrating multiple non-specific chemoresistive sensors together in arrays, a cross-reactive array can be realized, …
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Applying the Herman-Beta probabilistic method to MV feeders
… Following this, the input parameters for feeder impedance and load current are modified to include the effects of reactance and non-unity power factor loads, using approximate modelling techniques. For reactance, the modulus or absolute value of the complex impedance is used in place of the …
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Development and optimization of reconfigurable planar lenses and reflectors
… networks, which save costs and manufacturing complexity. Furthermore, the guided-wave approach to those arrays allows to perform a modular design: the radiating elements and the phase shifter are optimized independently. For the best reconfigurability capabilities, the phase shifter should be …
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Impedimetric Sensor System for Edible Oil Quality Assessment
… a capacitive sensor and the measurement of its impedance change. The main challenge thereby is that the impedance changes are very small and stray capacitances have a big influence on the measurements. In this context, this work proposes a sensor system with high accuracy able to detect the …