The De Hoop Vlei is an internationally registered wetland of great ecological richness which is situated partly within the first and largest nature reserve established by the Cape Department of Nature and Environmental Conservation. This vlei has flooded twice and been dry on four occasions this century. There has been speculation that land management practices in the catchment are the cause of such extremes. This claim is investigated with reference to established techniques for modelling runoff from rainfall data. As background to the study the characteristics of the De Hoop catchment have been documented. This information was not previously available and provides an essential basis for further study of conditions in De Hoop Vlei. It is found that whilst large differences in runoff may occur in localised areas due to changing land management practices, because of the composite hydraulic characteristics of the entire catchment it is not possible at the present time to provide a final answer to the question of whether stream to De Hoop has changed significantly due to human impact. Nevertheless, some important environmental changes affecting basin capacity and biological factors at De Hoop have been elucidated by this study.

Proefschrift--Utrecht. / Vita.

Proefschrift--Faculteit der sociale wetenschapen--universiteit Leiden, 2000. / Bibliogr. p. 292-298.

Inaug.-Diss.--Munich. / Vita. Includes bibliographical references.

Thesis (MEd)--PU vir CHO

Proefskrif--PU vir CHO

Thesis (MEd)--PU vir CHO

Proefskrif--PU vir CHO

No description available.

The brain, like many parts of the human body, can experience swelling, also known as cerebral edema. Cerebral edema may occur because of an injury, health related issues, tumors, or even high altitudes[1]. When cerebral edema occurs, a rise in intracranial pressure (ICP) becomes prevalent and may cause a serious threat. Without immediate treatment, increased intracranial pressure can prevent blood from flowing to the brain and depriving it of necessary oxygen it needs to function. A normal ICP is usually between 5-15 mmHg (666 Pa - 1333Pa). Any ICP observed to be above 20 mmHg (2666Pa) can be associated with brain ischemia and is usually treated[2, 3]. If prolonged, high intracranial pressures can be fatal. Current methods of measuring increased ICP are invasive and may involve drilling into the skull. Extreme invasive measures are not always suitable for certain situations. This thesis presents a study of a non-invasive sensor using piezoelectric PVDF wire to measure the ICP. The PVDF wire sensor is wrapped around the outer portion of the human head to measure the integrated hoop strain. Using this hoop strain, the pressure is then calculated from a known coupling factor of strain to pressure outputted from finite element modeling simulations. The coupling factor is then incorporated into a final calibration factor to calibrate the piezoelectric PVDF wire sensor from charge (Picocoulomb) to pressure (Pascal). These calibration factors are proven to be primarily dependent on the circumference of the human skull. Furthermore, part of this study analyzed the effectiveness and validity of the sensor due to asymmetries in the human skull. A comparison of analytical analysis results versus computational results using finite element modeling simulations show that the PVDF wire sensor neglects any asymmetries presented within the test subject. The results of this study show that this sensor will output correct ICP measurements of different subjects using appropriate calibration factors and is a viable option for measuring ICP non-invasively. / Master of Science