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MSc. (ARST) North-West University, Mafikeng Campus, 2003

This thesis investigates variations in solar irradiance incident upon sloping surfaces under deciduous forest in winter. A model is presented for prediction of solar irradiance at the surface which accounts for slope inclination and orientation, surrounding topography, isotropic absorption of solar radiation by the crown space, and shadows cast by the stem space. / Field data from two sites of different slope and aspect attest to the validity of the model; errors, based on 20-minute averages of instantaneous values, are 15.5% (RMSE) and $-$1.9% (MBE). Error is partially due to reliance upon global radiation measurements above canopy at a different site (partially cloudy conditions) and sampling error (sunny sky conditions). The variability of solar irradiance at the surface, and in the error of predicted values, is found to vary with sky condition, solar zenith and incidence angles, and slope orientation. However, integration to hourly and/or daily time periods improves model performance significantly.

Thesis (MTech (Radiography))--Cape Peninsula University of Technology, 2010. / The focus of this study is the role of the Radiation Therapist (RTT) in the assessment of pain in cancer patients. The study was carried out at a Radiotherapy Department of a large Teaching Hospital in Ghana and addressed the following research questions; 1) What is the role of the RTT in the assessment of pain in cancer patients, 2) Why should the RTTs’ role be extended to include pain assessment, 3) What are the challenges for the RTT when taking on the role of pain assessment in radiation oncology and 4) How can pain assessment become a routine role for the RTT in a busy radiation oncology department? 5) How would this extended role of the RTT assist management of patient? This study was conducted because many cancer patients suffer pain and to many, it can be more debilitating than the primary disease itself. The RTTs who are involved in the daily management of cancer patients during their radiation treatment can find it stressful to witness their patients going through such pain particularly when they do not have a role in the management of pain. In Ghana, there are few radiation oncologists (ROs) and therefore an extended scope for RTTs, that includes pain assessment and a meaningful contribution to the management of their patients’ pain, would be advantageous to all. A mixed method research approach was adopted for gathering quantitative and qualitative data. This included data collection of; interview, observation and review of existing document. A pain questionnaire SF-MPQ-2 by Melzack (2009) was adapted as a tool for assessing pain in the study participants.

No description available.

Recent satellite measurements have found the range of solar radiation flux at the mean Earth-Sun distance to be from 1365 to 1372 W/m², or 1368 W/m² to within ±0.5 percent. This regularity is considered sufficient to permit the use of solar radiation as a source of energy for inflight calibration of radiometers designed to detect electromagnetic radiation in the solar spectrum. But direct viewing of the Sun would provide a flux considerably greater than the operating range of radiometers designed to observe typical Earth scenes. Therefore an attenuator is required. The Earth Radiation Budget Experiment (ERBE) radiometers, operational since 1984, relied on a mirror attenuator mosaic (MAM) to attenuate the solar energy. The ERBE MAM is an array of 105 tightly packed concave spherical mirrors with a black mask covering the surface between the hemispherical cavities and partially covering the cavities themselves. In principle, the reflection of solar energy by the MAM was anticipated to be independent of the solar incidence direction. Unfortunately, flight data revealed a variation with a solar incidence angle of as much as 20 percent for flux arriving at the detector during solar calibration. An improvement of the ERBE MAM design, suppression of the black mask, and reduction of the surface area of the spherical mirrors, has been achieved for the Clouds and the Earth's Radiant Energy System (CERES) radiometers, which will be operational sometime in the late-1990's. The topic of this thesis is the creation of a thermal-radiative model, based on the Monte-Carlo ray-trace method, to characterize the performance of the CERES MAM. The radiative analysis suggests that the current CERES MAM design is still somewhat less than optimal. The desired specifications are that the fraction of solar energy reflected by the MAM to the radiometer aperture be independent of the solar vector, and that the distribution of this reflected energy be uniform across the entire surface area of the radiometer aperture. The work reported here establishes that these specifications can be met by a simple reorientation of the MAM diffuser plate. / Master of Science

The basic resource of all solar systems is the sun, and a knowledge of the quantity of the energy available is of prime importance. Although the solar radiation outside the atmosphere is known and almost constant, various climatic factors cause wide variations in its value on the earth's surface. In addition, the relative position of the sun with respect to local points of interest will allow surfaces with different orientations and tracking ability to receive different quantities of solar energy. This research focuses on the effect of cloud cover on the solar radiation received on the earth's surface and presents computer models that calculate its value for the best system configuration. Then a complete assessment of the electrical output of such a system is given. With this purpose in mind, two solar resource evaluation models have been developed; the first method is based on a direct statistical approach correlating clear sky total daily radiation with measured daily insolation. This approach has been applied to a few selected sites and offers the procedure for extending the same coefficients to other sites with similar weather patterns. This model has been tested for six sites in Bangladesh . These sites are located around a "reference" site . The predictions made have shown to be quite accurate. The second model uses an analytical approach that combines clear sky methods with "correction" factors which are based on long term recorded solar ra- diation. In addition, this model has been enhanced by an algorithm that selects the optimal surface orientation that maximizes solar output. Finally, the hourly electrical output of the photovoltaic system is calculated after accounting for the various losses. This is presented as part of a complete solar energy evaluation model. / M.S.