Search

This study reports solar-thermal pyrolysis of mallee wood powders driven by direct concentrated solar radiations at different temperatures (1540, 1740, and 1930 °C), heating rates (320, 800, and 3200 °C/min), and holding times (0 and 5 min). Under such severe pyrolysis conditions, solar-thermal pyrolysis of mallee wood produces predominantly volatiles (≥90 wt %), with very low char yields (≤10 wt %), as reported on a dry basis. Majorities of inherent alkali and alkaline earth metallic (AAEM) species are also released into the gaseous phase. The severe pyrolysis conditions also lead to the low reactivity of char products as a result of not only the char carbon structure becoming ordered and graphitized (as evidenced by the Raman data) but also significant losses of catalytic AAEM species in the char. For example, during the solar-thermal pyrolysis of mallee wood at 1930 °C, 800 °C min–1, and 5 min holding time, the char yield is only ∼5 wt %, the retentions of Na and Mg are ∼1%, the retentions of K and Ca are only 13 and 35%, respectively, and the char is less reactive. Therefore, despite the low char yield, char conversion is still a critical consideration in the design and operations of solar-thermal reactors under these conditions because the char is very inert.

This study reports solar-thermal pyrolysis of mallee wood powders driven by direct concentrated solar radiations at different temperatures (1540, 1740, and 1930 °C), heating rates (320, 800, and 3200 °C/min), and holding times (0 and 5 min). Under such severe pyrolysis conditions, solar-thermal pyrolysis of mallee wood produces predominantly volatiles (≥90 wt %), with very low char yields (≤10 wt %), as reported on a dry basis. Majorities of inherent alkali and alkaline earth metallic (AAEM) species are also released into the gaseous phase. The severe pyrolysis conditions also lead to the low reactivity of char products as a result of not only the char carbon structure becoming ordered and graphitized (as evidenced by the Raman data) but also significant losses of catalytic AAEM species in the char. For example, during the solar-thermal pyrolysis of mallee wood at 1930 °C, 800 °C min–1, and 5 min holding time, the char yield is only ∼5 wt %, the retentions of Na and Mg are ∼1%, the retentions of K and Ca are only 13 and 35%, respectively, and the char is less reactive. Therefore, despite the low char yield, char conversion is still a critical consideration in the design and operations of solar-thermal reactors under these conditions because the char is very inert.

This report summarizes the activities that were carried out in the framework of Subtask 2 of IEA Annex 58. Subtask 2 dealt with the challenge of optimizing full scale dynamic testing. The aim was to arrive at a roadmap presenting the user with reliable methods used to measure the actual thermal performance of building components and whole buildings. The roadmap (using a decision tree logic) is aimed at multiple audiences from both academic and industry backgrounds. The present report focuses on the development of the Decision Tree and how it changed throughout the course of Annex 58, giving an overview of the presented work.

This paper presents a methodology for evaluating the photometric and colorimetric characteristics of internal building materials, for daylight evaluation. The assessment of these characteristics is crucial both for modelling materials accurately in daylight simulation tools and for building correct daylight mock-ups. The essential photometric and colorimetric parameters that influence the reflection of light from and its transmission through building materials are identified and described. Several methods for evaluating these parameters qualitatively and quantitatively are then proposed and discussed. Our new methodology was fused to create a database of materials in a freely accessible web tool which compares full-size materials to scale-model materials in order to help architects and lighting designers choose materials for building daylight scale models. (C) 2007 Elsevier Ltd. All rights reserved.

This paper presents a web tool that has been developed in order to help architects or lighting designers to choose materials for the building of daylight scale models. Those scale models are built in order to qualify or quantify, under real or artificial skies, the daylight penetration and distribution in buildings. The essential photometric and colorimetric parameters that influence the light reflection and transmission of building materials were identified and several methods, for the qualitative and the quantitative evaluation of these parameters were studied. As a result of this study, the web tool proposes two input possibilities. The first one is the simplest: the user chooses the full size material in a database and the web tool immediately proposes a list of scale model materials. The second one is based on a complete input of the full size material characteristics: its colour that can be measured or identified by a colour code (RAL, NCS, ⋯) and its reflexion mode and its homogeneity that are then qualitatively described. In this second case, again, the tool proposes a list of selected scale model materials and the user can then choose a material in that list in accordance with the main objectives of his daylight study. In addition, the web tool proposes, as illustration, RADIANCE simulation results like illuminance values, in a reference office room with walls made of the full size material, and animations showing the importance of wall lightness on inside daylight distribution.

This paper presents a web tool that has been developed in order to help architects or lighting designers to choose materials for the building of daylight scale models. Those scale models are built in order to qualify or quantify, under real or artificial skies, the daylight penetration and distribution in buildings. The essential photometric and colorimetric parameters that influence the light reflection and transmission of building materials were identified and several methods, for the qualitative and the quantitative evaluation of these parameters were studied. As a result of this study, the web tool proposes two input possibilities. The first one is the simplest: the user chooses the full size material in a database and the web tool immediately proposes a list of scale model materials. The second one is based on a complete input of the full size material characteristics: its colour that can be measured or identified by a colour code (RAL, NCS, ⋯) and its reflexion mode and its homogeneity that are then qualitatively described. In this second case, again, the tool proposes a list of selected scale model materials and the user can then choose a material in that list in accordance with the main objectives of his daylight study. In addition, the web tool proposes, as illustration, RADIANCE simulation results like illuminance values, in a reference office room with walls made of the full size material, and animations showing the importance of wall lightness on inside daylight distribution.

n/a

n/a

n/a

The Raman spectroscopy have allowed us to perform studies on singlewalled nanotubes (SWNT's) produced by following methods: electric arc, laser ablation and solar energy. As this characterization method provides a great deal of informations, we will present a comparison between the nanotubes produced by all these processes and the influence of some synthesis parameters. By using spin casting, we have produced thin films of PMMA-SWNT's for different concentrations. Then, we have characterized these new materials by Raman spectroscopy. The aim of these investigations is to get information on the possible interactions between these two materials. In particular, we have studied the evolution of the composites films spectra as a function of the nanotubes concentration in the polymer.

The total extraction was investigated of S by vaporisation from iron sulphide ores in the presence or absence of methane or carbon powder. The ore studied contained 54.65% Fe, 0.45% Pb, 2.325% Zn and 0.74% Cu. Secondary metal composition had not previously been considered, having no effect on S vaporisation, but even very low concentrations of metals such as Cu in the recovered iron would give it low mechanical resistance and make it useless. The residue was investigated using Auger electron spectroscopy, energy-dispersive X-ray spectroscopy and wavelength-dispersive spectroscopy. Thermodynamic analyses were carried out of the Fe-S, Fe-S-C, Fe-S-C-H and Fe-S-O-H systems at high temperature. When the pyrrhotite was treated alone, Cu was completely evaporated after the decomposition of Cu2S. In the presence of carbon, iron was present as the core form in the iron sulphide. In this case, the vaporisation kinetics were very fast and no traces of secondary metals were detected in the iron core., The total extraction was investigated of S by vaporisation from iron sulphide ores in the presence or absence of methane or carbon powder. The ore studied contained 54.65% Fe, 0.45% Pb, 2.325% Zn and 0.74% Cu. Secondary metal composition had not previously been considered, having no effect on S vaporisation, but even very low concentrations of metals such as Cu in the recovered iron would give it low mechanical resistance and make it useless. The residue was investigated using Auger electron spectroscopy, energy-dispersive X-ray spectroscopy and wavelength-dispersive spectroscopy. Thermodynamic analyses were carried out of the Fe-S, Fe-S-C, Fe-S-C-H and Fe-S-O-H systems at high temperature. When the pyrrhotite was treated alone, Cu was completely evaporated after the decomposition of Cu2S. In the presence of carbon, iron was present as the core form in the iron sulphide. In this case, the vaporisation kinetics were very fast and no traces of secondary metals were detected in the iron core.