Katumba, GBaisitse, TForbes, AOlumekor, LWackelgard, E2009-02-122009-02-122006-07Katumba, G, Baisitse, T, Forbes, A et al. 2006. Carbon-in-silica composite selective solar absorbers: a determination of composition and dielectic properties. 51st Annual Conference of the SAIP, University of the Western Cape, South Africa, 3-7 July 2006, pp 1http://hdl.handle.net/10204/299351st Annual Conference of the SAIP, University of the Western Cape, South Africa, 3-7 July 2006The Bruggeman and Maxwell-Garnett effective medium approximations (EMAs) have been used to investigate optical properties of composite materials. The EMA assumptions are based on random unit cell models in which metal particles are embedded in a dielectric medium. The embedded particles can be varied between spherical, ellipsoidal and cylindrical shapes. An interesting structure of connected short chains of amorphous carbon intermixed with silica chains at nanoscale level has been observed. The Bruggeman and Maxwell-Garnett EMAs could not model the optical properties of these materials; neither could the Bergman-Milton bounds approach. A generalised Bergman representation is applied on these carbon-in-silica samples with successful fitting between experiment and theory. The curve-fitting procedure resulted in information such as volume fraction of carbon relative to silica, percolation threshold and film thicknessenSolar absorbersReflectanceComposite coatingCarbon nano-chainsFilms thicknessCarbon volumePercolation thresholdsConference PresentationKatumba, G., Baisitse, T., Forbes, A., Olumekor, L., & Wackelgard, E. (2006). Carbon-in-silica composite selective solar absorbers: a determination of composition and dielectic properties - SAIP Poster. http://hdl.handle.net/10204/2993Katumba, G, T Baisitse, A Forbes, L Olumekor, and E Wackelgard. "Carbon-in-silica composite selective solar absorbers: a determination of composition and dielectic properties - SAIP Poster." (2006): http://hdl.handle.net/10204/2993Katumba G, Baisitse T, Forbes A, Olumekor L, Wackelgard E, Carbon-in-silica composite selective solar absorbers: a determination of composition and dielectic properties - SAIP Poster; 2006. http://hdl.handle.net/10204/2993 .TY - Conference Presentation AU - Katumba, G AU - Baisitse, T AU - Forbes, A AU - Olumekor, L AU - Wackelgard, E AB - The Bruggeman and Maxwell-Garnett effective medium approximations (EMAs) have been used to investigate optical properties of composite materials. The EMA assumptions are based on random unit cell models in which metal particles are embedded in a dielectric medium. The embedded particles can be varied between spherical, ellipsoidal and cylindrical shapes. An interesting structure of connected short chains of amorphous carbon intermixed with silica chains at nanoscale level has been observed. The Bruggeman and Maxwell-Garnett EMAs could not model the optical properties of these materials; neither could the Bergman-Milton bounds approach. A generalised Bergman representation is applied on these carbon-in-silica samples with successful fitting between experiment and theory. The curve-fitting procedure resulted in information such as volume fraction of carbon relative to silica, percolation threshold and film thickness DA - 2006-07 DB - ResearchSpace DP - CSIR KW - Solar absorbers KW - Reflectance KW - Composite coating KW - Carbon nano-chains KW - Films thickness KW - Carbon volume KW - Percolation thresholds LK - https://researchspace.csir.co.za PY - 2006 T1 - Carbon-in-silica composite selective solar absorbers: a determination of composition and dielectic properties - SAIP Poster TI - Carbon-in-silica composite selective solar absorbers: a determination of composition and dielectic properties - SAIP Poster UR - http://hdl.handle.net/10204/2993 ER -