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<p> An investigation of the effects of cumulus clouds on solar radiation was carried out during the 1977 field season at McMaster University, Hamilton. The measurement of total incoming solar radiation, direct beam radiation and the diffuse flux calculated as a residual, were used to draw inferences regarding the transmission properties of cumulus clouds, both on a daily basis and for different cloud fields, The diffuse flux, showing the greatest variability, was sub-divided into three components and each were evaluated under unobscured and obscured sun conditions. Measured values were compared with those derived for a model atmosphere.</p> / Thesis / Bachelor of Arts (BA)

Entomopathogenic fungi are highly susceptible to the damaging effects of solar radiation. Attempts to protect entomopathogenic fungi from solar radiation have been, for the most part, unsuccessful. A new strategy for formulating entomopathogenic fungi for protection from solar radiation and desiccation has been developed tested using the acridid entomopathogen Metarhizium anisopliae var acridum (IMI 330189). This strategy involves coating spores with water-soluble materials that provide protection from solar radiation and enhance spore survival during drying. Development of this formulation involved the following: 1) production of an infective spore-type in liquid culture that could survive drying; 2) coating spores during an air-drying process; 3) reducing formulation particle size for oil suspension; 4) testing the effects spore coating on spore-tolerance simulated sunlight; and 6) testing the effects of spore coating infectivity to Schistocerca americana. Aerial conidia, submerged conidia, and blastospores produced in a high-osmolality liquid medium all had high desiccation tolerance relative to blastospores produced in Adamek's media. Blastospores produced in high osmolality medium were the most infective to S. americana in an aqueous 20% molasses solution followed by submerged conidia and aerial conidia, with LT50 values (95% C.I.) at 1 x 106 spores/insect of 7.8 d (6.7 to 9.0 d), 10.5 d (9.5 to 11.6 d), 14.6 d (11.9 to 18.0 d), respectively. Comparisons were made among cell-wall characteristics of these spore-types, including cell-wall thickness, lectin-binding, charge, and hydrophobicity. An optimal spore-coating formulation was selected on the basis of spore survival and germination over time after air-drying, particle-size reduction, and storage at 28 Ë C. This spore-coating formulation, consisting of skim milk, Kraft lignin (Curan 10®) and glycerol, greatly improved the tolerance of aerial conidia and submerged conidia to simulated sunlight, increasing the LT50 (95% C.I.) of aerial conidia from 4.0 hr (3.1-5.1) to 17.0 hr (12.5-23.0). The spore coating formulation decreased the infectivity of spores in oil to adult S. americana; reducing the LT50 values of aerial conidia at a dose of 1 x 105 spores / insect from 5.8 d (4.9-6.9 d) to 8.2 d (7.3-9.3 d). / Ph. D.

<p> Simultaneous solar radiation and meteorological observations were taken from an instrumented tower located in southwestern Lake Ontario. During the four month period of this study (July-November, 1969) it was found that short-term fluxes of incoming global radiation could be predicted with a standard error which was better than 0.05 cal cm^-2min^-1 under cloudless conditions. Under cloudy conditions the lowest standard of prediction error (0.14 cal cm^-2min^-1) was obtained using a model which takes into account cloud type transmission. Under cloudless conditions the Fresnel curve underpredicts the albedos observed for low zenith angles and overpredicts when the zenith angle is high. This is mostly due to a backscatter effect estimated to be between 1.5 to 2% and to the albedo of diffuse radiation which was confirmed to be 6.5 to 7%.</p> / Thesis / Master of Science (MSc)

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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.

Master of Science in Engineering (Electrical) University of the Witwatersrand July, 2016 / This dissertation uses historical electrical consumption/load and actual solar radiation data to design a solar array for the University of the Witwatersrand’s West Campus. The array must meet the campus’s minimum demand as selling excess generated power back to the utility is not possible at this stage. The financial and spatial impact of adjusting the size of the array, design losses and cloud cover are also investigated. In addition to this, the influence on the payback period of financial variables such as taxes, electricity and start-up costs are also explored. The solar array system design process starts by determining the amount of power that the array must produce or supplement. Thereafter, load estimates and electrical consumption figures that are provided by utility bills or measured with load monitoring equipment are analysed. Furthermore, system losses are factored in which ultimately increases the size of the array. Once all the input variables are analysed, the amount of available solar radiation in the area where the array will be installed is required to determine the amount of energy that the array can produce. Several free databases with this information are available but it is found that this data over predicts the availability of solar radiation. The University has been monitoring the electrical consumption of West Campus since 2012 and solar radiation data is also available for this site. Comparing the satellite derived and measured datasets found that the ground monitored data is 25 % more accurate and therefore better suited for designing a solar array. Individually adjusting the design and financial variables changes the payback period between 3 – 17 %. Combining all the variables can reduce the payback of option 1 from 9.6 years to 6.1 years. Clear legislation needs to be developed for the uptake of renewable energy resources and supported by better rebates for renewable users and harsher taxes for non-renewable users. Should legislation change and if additional capital is available, a larger array will benefit the University more and should be installed as the difference between payback periods is not significant. This is mainly due to decreased costs associated with a higher yield. The financial benefits of a larger array will also be more lucrative if better rebates are enforced. / MT2017