Foreign Object Detection for Electric Vehicle Wireless Charging

Wireless power transfer technology is being widely used in electric vehicle wireless-charging applications, and foreign object detection (FOD) is an important module that is needed to satisfy the transmission and safety requirements. FOD mostly includes two key parts: metal object detection (MOD) and living object detection (LOD), which should be implemented during the charging process. In this paper, equivalent circuit models of a metal object and a living object are proposed, and the FOD methods are reviewed and analyzed within a unified framework based on the proposed FOD models. A comparison of these detection methods and future challenges is also discussed. Based on these analyses, detection methods that employ an additional circuit for detection are recommended for FOD in electric vehicle wireless-charging applications

Computational Modelling of Electrical Properties of Thyroid and Parathyroid Tissue

Parathyroid gland identification is an important consideration in order to decrease the inci- dence of post-surgical complications associated with thyroid surgeries. Electrical Impedance Spectroscopy (EIS) based tissue differentiation recently emerged as a promising non-invasive technique that could enhance the tissues separation, and parathyroid preservation in a surgery setting. The aim of the work presented in this thesis is to implement a computational modelling approach in order to elucidate the differences between healthy thyroid and parathyroid tissue impedance spectra which could permit their differentiation during surgery. Multiscale finite element thyroid and parathyroid models have been constructed with the main objective to investigate the impact of morphology and composition on the bulk electrical behaviour of both tissues. The multiscale pipeline represents the hierarchical tissue structure from cellu- lar to tissue scale including a novel mesoscale for the thyroid follicular arrangements. A comprehensive inter- and intracompartmental sensitivity study provided an insight into the impact of the variations in geometrical and electrical properties of tissue structures on electrical impedance spectra of both tissue types suggesting a successful separability between the computed thyroid and parathyroid impedance spectra indices. Moreover, the modelled results obtained through the variation of geometrical parameters demonstrating the natural variability in tissue morphology provided a good agreement with the in vivo measured data acquired and published by Hillary et al. In addition, the verification of selected homogeneity assumptions and the exploration of measurement accuracy and di↵erent probe configurations provided further recommendations for future work concerning computational modelling, experimental data collection and EIS device design improvements. In particular, the outcomes of this computational study re- vealed the importance of additional experimental work concerning the electrical properties measurements of biological tissue materials, and the significance of tissue preparation and measurement accuracy in obtaining thyroid and parathyroid measurements with a tetrapolar EIS probe

Numerical modelling of electrical stimulation for cartilage tissue engineering

In this thesis, the design and validity of numerical models of electrical stimulation for cartilage tissue engineering are critically assessed at different scales. In sum, the results of this thesis pave the way for experimentally validated numerical models of electrical stimulation devices for cartilage tissue engineering. Furthermore, models of tissue samples can be developed down to the cellular scale and will contribute to the development of patient-specific stimulation approaches

Swept frequency biompedance analysis for the determination of body water compartments

Bioelectrical impedance analysis, (BIA), is a method of body composition analysis first investigated in 1962 which has recently received much attention by a number of research groups. The reasons for this recent interest are its advantages, (viz: inexpensive, non-invasive and portable) and also the increasing interest in the diagnostic value of body composition analysis. The concept utilised by BIA to predict body water volumes is the proportional relationship for a simple cylindrical conductor, (volume oc length2/resistance), which allows the volume to be predicted from the measured resistance and length. Most of the research to date has measured the body's resistance to the passage of a 50· kHz AC current to predict total body water, (TBW). Several research groups have investigated the application of AC currents at lower frequencies, (eg 5 kHz), to predict extracellular water, (ECW). However all research to date using BIA to predict body water volumes has used the impedance measured at a discrete frequency or frequencies. This thesis investigates the variation of impedance and phase of biological systems over a range of frequencies and describes the development of a swept frequency bioimpedance meter which measures impedance and phase at 496 frequencies ranging from 4 kHz to 1 MHz. The impedance of any biological system varies with the frequency of the applied current. The graph of reactance vs resistance yields a circular arc with the resistance decreasing with increasing frequency and reactance increasing from zero to a maximum then decreasing to zero. Computer programs were written to analyse the measured impedance spectrum and determine the impedance, Zc, at the characteristic frequency, (the frequency at which the reactance is a maximum). The fitted locus of the measured data was extrapolated to determine the resistance, Ro, at zero frequency; a value that cannot be measured directly using surface electrodes. The explanation of the theoretical basis for selecting these impedance values (Zc and Ro), to predict TBW and ECW is presented. Studies were conducted on a group of normal healthy animals, (n=42), in which TBW and ECW were determined by the gold standard of isotope dilution. The prediction quotients L2/Zc and L2/Ro, (L=length), yielded standard errors of 4.2% and 3.2% respectively, and were found to be significantly better than previously reported, empirically determined prediction quotients derived from measurements at a single frequency. The prediction equations established in this group of normal healthy animals were applied to a group of animals with abnormally low fluid levels, (n=20), and also to a group with an abnormal balance of extra-cellular to intracellular fluids, (n=20). In both cases the equations using L2/Zc and L2/Ro accurately and precisely predicted TBW and ECW. This demonstrated that the technique developed using multiple frequency bioelectrical impedance analysis, (MFBIA), can accurately predict both TBW and ECW in both normal and abnormal animals, (with standard errors of the estimate of 6% and 3% for TBW and ECW respectively). Isotope dilution techniques were used to determine TBW and ECW in a group of 60 healthy human subjects, (male. and female, aged between 18 and 45). Whole body impedance measurements were recorded on each subject using the MFBIA technique and the correlations between body water volumes, (TBW and ECW), and heighe/impedance, (for all measured frequencies), were compared. The prediction quotients H2/Zc and H2/Ro, (H=height), again yielded the highest correlation with TBW and ECW respectively with corresponding standard errors of 5.2% and 10%. The values of the correlation coefficients obtained in this study were very similar to those recently reported by others. It was also observed that in healthy human subjects the impedance measured at virtually any frequency yielded correlations not significantly different from those obtained from the MFBIA quotients. This phenomenon has been reported by other research groups and emphasises the need to validate the technique by investigating its application in one or more groups with abnormalities in fluid levels. The clinical application of MFBIA was trialled and its capability of detecting lymphoedema, (an excess of extracellular fluid), was investigated. The MFBIA technique was demonstrated to be significantly more sensitive, (P<.05), in detecting lymphoedema than the current technique of circumferential measurements. MFBIA was also shown to provide valuable information describing the changes in the quantity of muscle mass of the patient during the course of the treatment. The determination of body composition, (viz TBW and ECW), by MFBIA has been shown to be a significant improvement on previous bioelectrical impedance techniques. The merit of the MFBIA technique is evidenced in its accurate, precise and valid application in animal groups with a wide variation in body fluid volumes and balances. The multiple frequency bioelectrical impedance analysis technique developed in this study provides accurate and precise estimates of body composition, (viz TBW and ECW), regardless of the individual's state of health

WOFEX 2021 : 19th annual workshop, Ostrava, 1th September 2021 : proceedings of papers

The workshop WOFEX 2021 (PhD workshop of Faculty of Electrical Engineer-ing and Computer Science) was held on September 1st September 2021 at the VSB – Technical University of Ostrava. The workshop offers an opportunity for students to meet and share their research experiences, to discover commonalities in research and studentship, and to foster a collaborative environment for joint problem solving. PhD students are encouraged to attend in order to ensure a broad, unconfined discussion. In that view, this workshop is intended for students and researchers of this faculty offering opportunities to meet new colleagues.Ostrav

Non-invasive Measurement of Cholesterol in Human Blood by Impedance Technique: an Investigation by Finite Element Field Modelling

The main topic of this work is detection of solid particles suspended in conductive medium and development of methodologies for determining cholesterol levels in human blood non-invasively by electrical impedance technique. The main part of this research is focused on the development of methodologies for numerical finite element (FE) modelling of simplified blood-cholesterol system, representing a real measurement system. This has been done first in 2D, to prove the concept and then in 3D, to take into account all of the effects that would only be present in 3D system as well as taking into account that there is a fully 3D problem in the heart of presented research. The proposed model has been tested in various extreme cases and theoretical and some experimental validations have been carried out to establish a degree of confidence in the modelling methodologies developed. This included novel way of model simplification by introduction of particle coagulation. This method has been proven to be successful replacement of effective conductivity method, used in the past. It has been tested against variation in physiological parameters, such as particle concentration and distribution, and material properties, such as particle ,conductivities. In 3D modelling cases the red blood cells (RBC) have been added to further increase the complexity of the system. Several case studies were used to help analyse which physical parameters of RBC would have the biggest impact on system’s impedance. Results were validated against experimental data where possible. This allowed extension of proposed methodology to non-spherical particles modelling. The other methodology adopted in this work applies to the electrode modelling. All electrodes are modelled as hollows. This tactic has been proven to work. It was validated both theoretically and by comparing computational model results with experiment results (BERG, City University London). In Conclusions, it is discussed that both methodologies can be used outside of current research in electromagnetic simulations of less conductive particles in conductive solvent and in cases where electrode material is not known. Modelling investigations of the simplified blood-cholesterol systems using the 2D and 3D FE modelling methodologies developed in this work have shown that it should be possible to measure cholesterol levels in human blood by impedance technique. Opinion sought from clinical staff highlight that this can potentially improve patient care by minimizing time needed for tests and human error (by shortening the number of people involved in testing). The work also establishes and discusses the need for further work, both theoretical and experimental for development of a measuring device for non-invasive measurement of cholesterol in human blood by impedance technique

Aerospace Medicine and Biology: Cumulative index, 1979

This publication is a cumulative index to the abstracts contained in the Supplements 190 through 201 of 'Aerospace Medicine and Biology: A Continuing Bibliography.' It includes three indexes-subject, personal author, and corporate source

Aerospace Medicine and Biology: A Cumulative Index to the 1985 Issues

This publication is a cumulative index to the abstracts contained in the Supplements 268 through 279 of Aerospace Medicine and Biology: A Continuing Bibliography. It includes seven indexes - subject, personal author, corporate source, foreign technology, contract number, report number, and accession number