City Research Online

Abstract

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.

Publication Type:	Thesis (Doctoral)
Subjects:	T Technology > TA Engineering (General). Civil engineering (General)
Departments:	School of Science & Technology > Engineering Doctoral Theses School of Science & Technology > School of Science & Technology Doctoral Theses

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