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M.Ing. / Fouling of suspended solids on piping and equipment causes severe operating and maintenance problems in process, water treatment and miningrelated plants. In the SASOL environment fouling related problems are mainly experienced on equipment operating in process cooling water services. Suspended solids appear in the form of activated sludge in the cooling water system and the solid particle sizes are usually submicron in size. Conventional solid liquid separation techniques like centrifuging, sedimentation, filtration, etc. could up to this stage not be applied successfully to remove the finest solids from the process cooling water system. The possibility to separate solid liquid suspensions by means of acoustic energy was investigated. The theoretical principles of acoustic waves, especially standing waves, were studied and explained. A theoretical model indicates that separation of solid/liquid suspensions can be obtained virtually immediately after acoustic energy is applied. Theoretically the size and frequency of a tipical acoustic transducer can be calculated for a specific application. Based on theoretical calculations and findings, an experimental setup was prepared to carryout experiments on different suspensions. A control suspension made-up of water and powder, of Yttlich the particle sizes were approximately 10 pm, was prepared and exposed to a standing acoustic wave. Separation was achieved successfully. Follow-up experiments were carried out to establish the optimum conditions to which separation could be achieved. Different flow velocities were tested as well as different power inputs. The best separation was achieved with the lowest flow rate of 2.5 mils and the highest available voltage of 12 Volt. These conditions were not only used to separate a control suspension but also in a real situation where it was attempted to separate suspended solids from the cooling water system. The attempts were unsuccessful. Additional experiments were also done on ash water and cooling water blowdown which also failed. The failure of effective separation of the process cooling water suspensions is due to the extremely small sizes of the solid partides in suspension. Greater energy input than was available for this project, is required as the particle sizes decreases. Provision needs to be made for all particle sizes to achieve effective results. The separation of solid liquid suspensions is achievable with the aid of acoustic energy. The physical properties of the suspension however determines the size and magnitude of the separating equipment. A proposal for the implementation of a full scale acoustic separation system is given. The proposal comprises of a parallel system to ensure continuity of the cooling process.

This thesis reports a summary of the PhD programme for the assessment of person‘s emotional anxiety using Electro-optical technology. The thesis focuses mainly on the understanding of fundamental properties of physiological responses to emotional anxiety and how they can be captured by using Electro-optical (EO) imaging methods such as hyperspectral imaging (HSI) and thermal imaging (TI) techniques. The thesis summarises three main areas of work that have been undertaken by the author in the programme: (a) Experimental set up including HSI system and data acquisition software design and implementation, (b) fundamental understanding of physiological responses to emotional anxiety from the EO perspective and (c) the development of a novel remote sensing technique for the assessment of emotions without the requirement of base line information. One of our main results is to provide evidence to prove that the mean temperature in the periorbital region remains the same within 0.2°C during emotional anxiety. Furthermore, we have shown that it is the high temperature pixels within the periorbital, which increases in numbers by a huge amount after 2 minutes of the onset of anxiety. We have also developed techniques to allow the assessment anxiety without the need of base line information. The method has been tested using a sample size of about 40 subjects, and achieved promising result. Technologies for the remote sensing of heart beat rate has been in great demand, this study also involves the development of heart beat detection using TI system. Moreover, we have also attempted for the first time to sense glucose concentration from the blood sample in-vivo using HSI technique remotely. / ©Cranfield University

The Electrocardiogram (ECG) is a tool measuring the electrical activity of the heart, and it is extensively used for diagnosis and monitoring of heart diseases. The ECG signal reflects not only the heart activity but also many other physiological processes. The respiratory activity is a prominent process that affects the ECG signal due to the close proximity of the heart and the lungs. In this thesis, several methods for the extraction of respiratory process information from the ECG signal are presented. These methods allow an estimation of the lung volume and the lung pressure from the ECG signal. The potential benefit of this is to eliminate the corresponding sensors used to measure the respiration activity. A reduction of the number of sensors connected to patients will increase patients’ comfort and reduce the costs associated with healthcare. As a further result, the efficiency of diagnosing respirational disorders will increase since the respiration activity can be monitored with a common, widely available method. The developed methods can also improve the detection of respirational disorders that occur while patients are sleeping. Such disorders are commonly diagnosed in sleeping laboratories where the patients are connected to a number of different sensors. Any reduction of these sensors will result in a more natural sleeping environment for the patients and hence a higher sensitivity of the diagnosis.

京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第19474号 / 理博第4134号 / 新制||理||1595(附属図書館) / 32510 / 京都大学大学院理学研究科物理学・宇宙物理学専攻 / (主査)准教授 荒木 武昭, 教授 佐々 真一, 教授 山本 潤 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM

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