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No description available.

This work presents the calibration of the energy response of the Sudbury Neutrino Observatory (SNO). The development of the energy response processor RSP and its use in setting the energy scale of SNO and reconstructing the energy of neutrino-like events is presented for each of the three phases of SNO: the pure heavy water phase, the salt phase, and the neutral current detector (NCD) phase. A 16N calibration source, producing mainly 6.13 MeV γ-rays, is the primary energy calibration source. It is used to set the energy scale of the detector and to test for errors in the energy calibration and reconstruction process. The errors associated with energy reconstruction in the pure heavy water and salt phase data, that is to be used in a low energy threshold solar 8B neutrino analysis, are derived for the RSP energy response processor and shown to be in agreement with other analyses. The largest of the errors, that associated with using the 16N source to set the energy scale of the detector, is improved through a detailed and thorough analysis. The calibration of the energy scale of the photomultiplier tube array in the third phase, with an array of 3He proportional counters (NCDs) distributed within the heavy water, is presented. The event energy reconstruction errors in the NCD phase are reassessed with more precise measurements and shown to be in agreement with the conservative estimates used in the analysis SNO presented in 2008. The implications of the improvements in the error are assessed and the solar 8B neutrino fluxes—charged current (CC), elastic scattering (ES), and neutral current (NC)—are determined to be: φCC = 1.68+0.09−0.07, φES = 1.79+0.25-0.22, and φNC = 5.52+0.48-0.45, in units of 10^6/cm^2/s. The errors quoted are the combined statistical and systematic uncertainties. These results are in good agreement with the results published by SNO in 2008 with a modest improvement in the CC measurement. / Thesis (Ph.D, Physics, Engineering Physics and Astronomy) -- Queen's University, 2009-09-23 01:40:45.237

Solar grade silicon is currently produced mainly through blending semiconductor grade silicon waste with metallurgical grade silicon. As the demand for solar cells continues to increase rapidly, soon demand will outstrip supply of semiconductor grade silicon waste. A process for producing solar grade silicon efficiently and without relying on other industries is needed. It is proposed to produce solar grade silicon of 6N purity (99.9999%) by reacting silicon tetrachloride with aluminum monochloride via the following reaction: 2 AlCl(g) + SiCl4(g)= Si(s) + 2 AlCl3(g) Aluminum monochloride is proposed as the reductant for silicon tetrachloride because it is an extremely strong reducing agent and the reaction will produce all gaseous by-products. Additionally, the aluminum trichloride produced can be recycled to form more aluminum monochloride, which is produced by reacting aluminum metal with aluminum trichloride in the following reaction: AlCl3(g) + 2 Al(l)= 3 AlCl(g) High yields of AlCl have only been found above 1200°C, with very little AlCl present in equilibrium with Al and AlCl3 at lower temperatures. The high temperatures under which AlCl can be found in larger quantities makes it difficult to determine if the AlCl3 reacting with Al is actually producing AlCl as opposed to another subhalide such as AlCl2. Numerous IR spectroscopy studies have been undertaken to confirm that the reaction of aluminum trichloride gas with molten aluminum does produce aluminum monochloride, with all such studies confirming that this theoretical path is correct. Unlike previous studies, which pass the AlCl3 gas over molten aluminum, it is proposed to bubble the AlCl3 gas into the molten aluminum. This should increase yield of aluminum monochloride, which was not a priority in previous studies. In order to achieve the project objectives a literature review of silicon manufacturing techniques as well as aluminum monochloride production was completed. Experiments to determine the rate of sublimation of aluminum trichloride were to be done in order to determine what temperature at which to sublime the aluminum trichloride. Aluminum trichloride was bubbled into aluminum metal to form aluminum monochloride with experimental conditions being varied to increase yield. Yield was determined through analysis of the reaction products, which was difficult due to the instability of aluminum monochloride, which dissociates at room temperature back into aluminum trichloride and aluminum metal. After the yield of aluminum monochloride was maximized, silicon tetrachloride was introduced into the reactor to react with the aluminum monochloride to form silicon metal. / Thesis (Master, Mining Engineering) -- Queen's University, 2011-09-18 18:16:36.31

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No description available.

This research investigates the collection of concentrating solar energy and its transmission through optical fibres for use in high temperature applications such as lunar in-situ resource utilisation (ISRU) programmes, solar power generation and solar surgery. A prototype collector, known as the Fibre Optic Concentrating Utilisation System (FOCUS), has been developed and is capable of delivering high energy fluxes to a remote target. Salient performance results include flux concentrations approaching 1000 suns with an overall optical efficiency of 13%, measured from the inlet of the collector to the fibre outlet. The system comprises a novel solar concentrator designed to inject solar energy into a four metre long fibre optic cable for the transmission of light to the target. A nonimaging reflective lens in the form of a 600 mm diameter ring array concentrator was chosen for the collection of solar energy. Advantageous characteristics over the more common parabolic dish are its rearward focusing capacity and single stage reflection. The ring array comprises a nested set of paraboloidal elements constructed using composite material techniques to demonstrate a low-cost, effective fabrication process. At concentrator focus, a fibre optic cable of numerical aperture 0.37 is positioned to transport the highly concentrated energy away from the collector. The cable is treated to withstand UV exposure and high solar energy flux, and allows flexibility for target positioning. A computational analysis of the optical system was performed using ray tracing software, from which a predictive model of concentrator performance was developed to compare with experimental results. Performance testing of FOCUS was conducted using energy balance principles in conjunction with a flat plate calorimeter. Temperatures approaching 1500°C and flux levels in the region of 1800 suns were achieved before injection to the cable, demonstrating the optical system's suitability for use in high flux applications. During testing, peak temperatures exceeding 900°C were achieved at the remote target with a measured flux of 104 W/cm2 at the cable outlet. The predicted optical efficiency was 22%, indicating that further refinements to the ray trace model are necessary, specifically with regard to losses at the inlet to the cable. FOCUS was able to demonstrate its usefulness as a test bed for lunar in-situ resource utilisation technologies by successfully melting a lunar soil simulant. The system permits further terrestrial-based ISRU research, such as oxygen production from regolith and the fabrication of structural elements from lunar soil. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2011.

A low-cost Direct Solar Radiation Detector (DSRD) was developed in house in the Department of Physics at the University of KwaZulu-Natal (Westville). A main use of this instrument is to gather solar energy data that are to be used in the design of systems that concentrate and convert solar energy into thermal energy (concentrating solar thermal energy systems). These data are compiled into a database from which the efficiency and potential use of many solar systems can be based. It was required that the detector was fully characterized with respect to spectral range, polar (angular) response and environmental stability. Based on this analysis it was also required to investigate possible ways of improving the detector. An Eppley Normal Incidence Pyrheliometer (NIP) mounted on an Eppley Sun Tracker (ST) was used as a reference instrument. The ST is a power driven tracker with an axis parallel to the Earth's axis of rotation. The NIP and DSRD were mounted together on the tracker in order to correlate their responses and also to calibrate the DSRD. The results indicate that the modified DSRD works better in that it follows the reference instrument. The correlation between the NIP data and the DSRD data is better with the value of correlation factor close to unity and the root mean square error value close to zero. This means that the modifications carried out on the detector have improved the low cost in-house detector and hence the quality of data collected. / Thesis (M.Sc.)-University of KwaZulu-Natal, Westville, 2004.

The purpose of this research program was to measure the efficiency of evacuated tube solar collectors under various operating conditions including: the angle of inclination towards the incident solar radiation, heat transfer fluid flow rate, glazing installation, and number of evacuated tubes. The operating conditions and configurations were chosen to represent realistic or probable installation scenarios and environmental conditions. Furthermore, the research aimed to identify the suitability of evacuated tube solar collectors to each of the scenarios. The scope of the research project was limited to the efficiency of a single tube, and various configurations of a 32-tube panel, not the entire solar domestic hot water or space heating system. Thus, factors such as heat loss in the tubing, solar storage tank, and heat exchanger efficiency were not investigated. The findings indicated that efficiency varied by approximately 5% in general between the different collector configurations.

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