Papers by Keyword: Optical Analysis

Abstract: Waste disposal in remote areas is a hurdle due to lack of active dumping space. Besides, improper dumping of waste on empty land can have a detrimental impact on the environment. Incineration of waste using thermal incineration (using a solar concentrator) can be utilized for mobile incineration devices to dispose of hazardous waste effectively with a limited space. The design and mobility of the solar dish for this purpose is one of the most important considerations. The modeling of the solar dish was performed on SOLIDWORKS® with APEX® for optical simulation. The simulation results showed a linear variation of flux coating to enable a more comprehensive cost benefit analysis for the design. The simulation was also used to check whether the required flux at focus (to achieve ignition) was achieved. Further work is required to validate the results.

Abstract: This study summarizes different characterisation methods performed with new carbon fibres(vCF - virgin carbon fibres) for structural applications as carbon fiber reinforced plastic (CFRP)as well as fiber samples which have been treated under different conditions. These parameters consistof combinations of temperature (400-600 C) and dwell time (30 - 60 min) in an oxidising atmospherein order to provide a fundamental basis for the definition of possible recycling processes to regain thehigh value raw material, i.e. the carbon fibre, after the use-phase of the initial CFRP-structure. The investigationsthat were performed on vCF and secondary fibres (rCF - recycled CF) show in very goodagreement, that below 500 C almost no degradation of the fibre is visible, between 500 and 600 C arapid decrease in different physical and mechanical properties occurs and above 600 C a recovery ofthe fiber in terms of a secondary use in high performance structural context seems not to be feasible.The investigations that were performed consist of optical microscopy for the measurement of the fibrediameter, the deformation of the cross section and a statistical analysis. The second method appliedwas the characterization of the monofilament density, alongside to the breaking force and elongation,leading to the calculation of tensile strength and Youngs Modulus and further statistical analysis ofWeibull Modulus and its decrease over temperature.

Abstract: In this paper, an optical analysis of parabolic trough collector with flat concentrating photovoltaic receiver is carried out by utilizing non-uniform intensity distribution model of the solar disk. The optical system simulation tool ASAP is used to analyze the parabolic trough system with single axis tracking having a mirror aperture of 1m and length of 3m. The impact of random errors including slope error, apparent change in sun’s width, tracking errors on the optical performance of trough system is carried out. The errors are assumed to follow Gaussian (normal) distribution and analyzed statistically. It is found that intercept factor increases with rim angle for given total error of 5, 10 and 20 mrad. Geometrical concentration ratio is varied to see the effect on the intercept factor and compared for various error values. The numerical results show that for De-focused performance (L=0.1f) the local concentration ratio value is 23 for the 45° rim angle. Numerical results are compared with the analytical data available in the literature which show good agreement.

Abstract: Cadmium sulfide (CdS) thin films were prepared using the chemical bath deposition method onto glass substrates at constant reaction temperature of 85 °C. Cadmium sulphate and thiourea were used as sources of Cd⁺² and S^-2 ions respectively. Films were prepared by varying cadmium concentration (viz. 1, 5 and 10 mM) keeping thiourea concentration constant (20 mM). These films were examined for their structural and surface morphologies by X-ray diffraction analysis (XRD) and atomic force microscopy (AFM). Analysis of results suggests that CdS nanorods grow with cadmium sulphate concentration of 10 mM. The optical properties were investigated using UVVIS spectrophotometer. The values of optical band gaps as-calculated from optical transmission measurements suggests that films have energy band gap in the range of 2.38-2.32eV decreases with increase of cadmium concentration.

Abstract: Reflected light optical analysis and Electron Backscatter Diffraction (EBSD) analysis have been used to m easure grain sizes in 2D Al foil samples, annealed for different times. There are significant differences in the results of the two techniques. It is shown that in Al it is possible to detect boundaries in optical images down to a misorientation angle of 7-8º. Nevertheless, in most samples the critical angle of easy etching lies above 10º. The observed differences in grain size measurements between optical analysis and EBSD analysis can be largely attributed to three phenomena: (1) individual samples may behave slighty differently due to differences in the effectiveness of etching (2) the grain size is heterogeneous over large areas and (3) the effect of etching is not only a function of misorientation angle but also grain boundary plane. Despite these uncertainties, optical analysis seems to be reliable for analysis of processes in which mainly grain boundaries with misorientation angle of > 10º are involved i.e. grain growth.