What Do Color Changes Reveal About an Outdoor Scene?

In an extended image sequence of an outdoor scene, one observes changes in color induced by variations in the spectral composition of daylight. This paper proposes a model for these temporal color changes and explores its use for the analysis of outdoor scenes from time-lapse video data. We show that the time-varying changes in direct sunlight and ambient skylight can be recovered with this model, and that an image sequence can be decomposed into two corresponding components. The decomposition provides access to both radiometric and geometric information about a scene, and we demonstrate how this can be exploited for a variety of visual tasks, including color-constancy, background subtraction, shadow detection, scene reconstruction, and camera geo-location.Engineering and Applied Science

The solubility limits of mixed spinel phases and their bearing on the phase relationships in the system MgO-Al O -Cr O -Fe O-CaO.SiO

SIGLELD:D50013/84 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Using mixture design of experiments to assess the environmental impact of clay-based structural ceramics containing foundry wastes

This work describes the leaching behavior of potentially hazardous metals from three different clay-based industrial ceramic products (wall bricks, roof tiles, and face bricks) containing foundry sand dust and Waelz slag as alternative raw materials. For each product, ten mixtures were defined by mixture design of experiments and the leaching of As, Ba, Cd, Cr, Cu, Mo, Ni, Pb, and Zn was evaluated in pressed specimens fired simulating the three industrial ceramic processes. The results showed that, despite the chemical, mineralogical and processing differences, only chrome and molybdenum were not fully immobilized during ceramic processing. Their leaching was modeled as polynomial equations, functions of the raw materials contents, and plotted as response surfaces. This brought to evidence that Cr and Mo leaching from the fired products is not only dependent on the corresponding contents and the basicity of the initial mixtures, but is also clearly related with the mineralogical composition of the fired products, namely the amount of the glassy phase, which depends on both the major oxides contents and the firing temperature. (C) 2015 Elsevier B.V. All rights reserved

Combining mixture design of experiments with phase diagrams in the evaluation of structural ceramics containing foundry by-products

This work compares the effects of the incorporation of foundry by-products (foundry sand dust and Waelz slag) on the technological properties of three different ceramic products fabricated with different clays and fired at different temperatures: wall bricks (850 degrees C), roof tiles (950 degrees C) and face bricks (1050 degrees C). To this aim, the mixture design of experiments (M-DoE) methodology was used to define the minimum number of mixtures necessary to model and predict the technological properties (water absorption, flexural strength, open porosity, linear firing shrinkage, weight loss and apparent density) in terms of raw materials contents: clay, foundry sand dust and Waelz slag. The results obtained were interpreted in terms of the chemical and mineralogical compositions of the final products, which showed the importance of combining the M-DoE methodology with the phase equilibrium predictions to better understand the development of the fired products final properties. (C) 2014 Elsevier B.V. All rights reserved

Granite waste and coffee husk ash synergistic effect on clay-based ceramics

Brazil produces massive amounts of granite sawing waste and coffee husk ash and their inadequate and, often, illegal disposal causes enormous environmental problems. In the past decade, these and other industrial wastes have been intensively studied aiming at determining their potential as alternative raw materials, particularly for the ceramic industry. This work describes research carried out on the joint incorporation of those wastes in ceramic roof tile formulations. The results indicated that the simultaneous use of both materials translates into a very forgivable industrial working range, both composition- and temperature-wise, which, given the technological properties values observed after firing at 1100 degrees C, enables industrial up-grade to wall tile production. As collateral benefits, the use of granite waste and coffee husk ash as alternative raw materials in the manufacture of clay-based products will relieve the stress on feldspars consumption and attenuate waste disposal concerns

Influence of Surface Area on the Flowability Behaviour of Self-Flow Refractory Castables

Alumina, with high melting point (2050°C), high hardness and mechanical strength, and excellent abrasion resistance, is one of the most common raw materials used in self-flow refractory castables (SFRC) for monolithic linings and is commercially available in various fine to coarse size classes. However, the performance of the refractory lining depends not only on the properties of its ingredients but also on its easy installation (good flowability). The aim of this work was to evaluate the relationship between the flowability index (FI) of fresh castable and the specific surface area (SSA) of its particles, which is mostly determined by the finer particles content. The results obtained showed that, by controlling the proportion between matrix and aggregate, it is possible to control the SSA of the refractory castable and find a mathematical relationship between the specific surface area and the minimum flowability index required to obtain a self-flow refractory castable. It is, thus, possible to optimize the refractory castable size composition and obtain an estimate for FI as a function of SSA. Using a minimum 45 wt.% matrix content in the castable mixture, a SSA value above 2.215 m2/g is obtained, which leads to FI ≥ 80%, the recommended value for self-flow.</jats:p

Setting behaviour of waste-based cements estimated by impedance spectroscopy and temperature measurements

Este trabajo describe el estudio del desarrollo de fases durante el fraguado de diferentes formulaciones de clinker preparados con residuos industriales o subproductos, denominados barros (generados en los procesos de recubrimientos industriales por anodizado de Al, en procesos de filtración/depuración de agua potable y en procesos de corte de mármol) y arenas de fundición. Con el objeto de comparar, se prepararon formulaciones similares a partir de materias primas comerciales de alta pureza y procesadas en idénticas condiciones. Para sortear las restricciones experimentales de inherentes a la aguja de Vicat (esto es, grandes cantidades de material), se realizaron medidas de resistividad eléctrica en corriente alterna (a.c.) de espectroscopía de impedancia para seguir el proceso de hidratación y fraguado. Durante el fraguado, la evolución de la temperatura de las pastas de agua/cemento se registró. Los estudios de espectroscopía de impedancia mostraron ser un método fiable y en algunos casos, pueden emplearse como técnica sensible para detectar el inicio de las reacciones de hidratación

Characterisation of Refractory Ceramic Pressed Body Containing Industrial Waste

This study investigates the use of an industrial refractory brick waste in the refractory based silica and alumina ceramic body. From the characterization of the waste, a mixture containing a clay, silica, alumina and waste was processed via wet route and sintered at 1400 °C. The specimens were evaluated in dry (density) and after sintering (linear shrinkage, density and modulus of rupture).Microstructural characterization by scanning electron microscopy (secondary electron) revealed a microstructure unevenly and a presence of big porous which shows also small amounts of vitreous phase, which can be related to sintering process not fully finished. The results for the linear shrinkage (about 6 %) and modulus of rupture at three points (about 63 MPa) showed that the mixture containing the refractory brick waste and the processing conditions were satisfactory for obtaining a suitable refractory material for the manufacture of bricks for melting furnaces.</jats:p