Study of the kinetics of decomposition of goethitein vacuo and pore structure of product particles

The kinetics of decomposition of-goethite were investigated, under vacuum conditions, in the temperature range 170–250° C. The experimental thermogravimetric traces were interpreted according to the shrinking core model for cylindrical particles. The Arrhenius plot of InK (kinetic constant) against 1/T yielded an activation energy of 119±9 kJ mol^–1 at 210° C. The highest specific area,S _BET=118.4±5.5 m² g^–1, of the reaction product-hematite, was obtained by decompsition at 225° C. Information about the formation of micropores and their evolution with temperature was also obtained.     

A Dynamic Integrated Framework for Software Process Improvement

Current software process models (CMM, SPICE, etc.) strongly recommend the application of statistical control and measure guides to define, implement, and evaluate the effects of different process improvements. However, whilst quantitative modeling has been widely used in other fields, it has not been considered enough in the field of software process improvement. During the last decade software process simulation has been used to address a wide diversity of management problems. Some of these problems are related to strategic management, technology adoption, understanding, training and learning, and risk management, among others. In this work a dynamic integrated framework for software process improvement is presented. This framework combines traditional estimation models with an intensive utilization of dynamic simulation models of the software process. The aim of this framework is to support a qualitative and quantitative assessment for software process improvement and decision making to achieve a higher software development process capability according to the Capability Maturity Model. The concepts underlying this framework have been implemented in a software process improvement tool that has been used in a local software organization. The results obtained and the lessons learned are also presented in this paper.     

A Simple Extension of the Osher Riemann Solver to?Non-conservative Hyperbolic Systems

We propose a simple extension of the well-known Riemann solver of Osher and Solomon (Math. Comput. 38:339?C374, 1982) to a certain class of hyperbolic systems in non-conservative form, in particular to shallow-water-type and multi-phase flow models. To this end we apply the formalism of path-conservative schemes introduced by Parés (SIAM J. Numer. Anal. 44:300?C321, 2006) and Castro et al. (Math. Comput. 75:1103?C1134, 2006). For the sake of generality and simplicity, we suggest to compute the inherent path integral numerically using a Gaussian quadrature rule of sufficient accuracy. Published path-conservative schemes to date are based on either the Roe upwind method or on centered approaches. In comparison to these, the proposed new path-conservative Osher-type scheme has several advantages. First, it does not need an entropy fix, in contrast to Roe-type path-conservative schemes. Second, our proposed non-conservative Osher scheme is very simple to implement and nonetheless constitutes a complete Riemann solver in the sense that it attributes a different numerical viscosity to each characteristic field present in the relevant Riemann problem; this is in contrast to centered methods or incomplete Riemann solvers that usually neglect intermediate characteristic fields, hence leading to excessive numerical diffusion. Finally, the interface jump term is differentiable with respect to its arguments, which is useful for steady-state computations in implicit schemes. We also indicate how to extend the method to general unstructured meshes in multiple space dimensions. We show applications of the first order version of the proposed path-conservative Osher-type scheme to the shallow water equations with variable bottom topography and to the two-fluid debris flow model of Pitman & Le. Then, we apply the higher-order multi-dimensional version of the method to the Baer?CNunziato model of compressible multi-phase flow. We also clearly emphasize the limitations of our approach in a special chapter at the end of this article.     

MIJ2K Optimization using evolutionary multiobjective optimization algorithms

This paper deals with the multiobjective definition of video compression and its optimization. The optimization will be done using NSGA-II, a well-tested and highly accurate algorithm with a high convergence speed developed for solving multiobjective problems. Video compression is defined as a problem including two competing objectives. We try to find a set of optimal, so-called Pareto-optimal solutions, instead of a single optimal solution. The two competing objectives are quality and compression ratio maximization. The optimization will be achieved using a new patent pending codec, called MIJ2K, also outlined in this paper. Video will be compressed with the MIJ2K codec applied to some classical videos used for performance measurement, selected from the Xiph.org Foundation repository. The result of the optimization will be a set of near-optimal encoder parameters. We also present the convergence of NSGA-II with different encoder parameters and discuss the suitability of MOEAs as opposed to classical search-based techniques in this field.     

Influence of the co-feeding of CO, H2, CO2 or H2O in the partial oxidation of methane over Ni and Rh supported catalysts

The influence of the addition of 5 vol.% of carbon monoxide, hydrogen, carbon dioxide or water to the feed of partial oxidation of methane was investigated over Ni/γ-Al₂O₃ and Rh/γ-Al₂O₃ catalysts. In addition to catalytic tests, thermodynamic calculations were performed to predict the effect of these gas co-feeds. Compared to the thermodynamic trends, differences in the influence of the co-feeding on catalytic performances were observed between both catalysts. Co-feeding of CO, H₂, CO₂ or H₂O can modify the oxidation state and dispersion of the metal component of the catalysts during reaction, and as a consequence, their performances. Changes in catalysts can be due to dynamic processes occurring during reaction. It is suggested to take these processes into account in a more complex kinetic equation for the reactions involved.     

π-Stacking of rhodamine B onto water-soluble polymers containing aromatic groups

Evidences of the π-stacking of rhodamine B onto poly(sodium 4-styrenesulfonate) are given by ¹H NMR spectroscopy. As a consequence of these π-π interactions, changes on the diafiltration and UV-vis absorbance and fluorescence patterns are shown comparing water-soluble polymers containing aromatic rings as poly(sodium 4-styrenesulfonate) and poly(N-methacryloyl-5-aminosalicylic acid) with other polyanions that do not contain aromatic rings as poly(sodium vinylsulfonate) and poly(acrylic acid).     

Combination of Feature Extraction Methods for SVM Pedestrian Detection

This paper describes a comprehensive combination of feature extraction methods for vision-based pedestrian detection in Intelligent Transportation Systems. The basic components of pedestrians are first located in the image and then combined with a support-vector-machine-based classifier. This poses the problem of pedestrian detection in real cluttered road images. Candidate pedestrians are located using a subtractive clustering attention mechanism based on stereo vision. A components-based learning approach is proposed in order to better deal with pedestrian variability, illumination conditions, partial occlusions, and rotations. Extensive comparisons have been carried out using different feature extraction methods as a key to image understanding in real traffic conditions. A database containing thousands of pedestrian samples extracted from real traffic images has been created for learning purposes at either daytime or nighttime. The results achieved to date show interesting conclusions that suggest a combination of feature extraction methods as an essential clue for enhanced detection performance     

Three-dimensional reconstruction of the left ventricle from two angiographic views: an evidence combination approach

Clinical interventional hemodynamic studies quantify the ventricular function from two-dimensional (2-D) X-ray projection images without having enough information of the actual three-dimensional (3-D) shape of this cardiac cavity. This paper reports a left ventricle 3-D reconstruction method from two orthogonal angiographic projections. This investigation is motivated by the lack of information about the actual 3-D shape of the cardiac cavity. The proposed algorithm works in 3-D space and considers the oblique projection geometry associated with the biplane image acquisition equipment. The reconstruction process starts by performing an approximate reconstruction based on the Cylindrical Closure Operation and the Dempster-Shafer theory. This approximate reconstruction is appropriately deformed in order to match the given projections. The deformation procedure is carried out by an iterative process that, by means of the Dempster-Shafer and the fuzzy integral theory, combines the information provided by the projection error and the connectivity between voxels. The performance of the proposed reconstruction method is evaluated by considering first the reconstruction of two 3-D binary databases from two orthogonal synthetized projections, obtaining errors as low as 6.48%. The method is then tested on real data, where two orthogonal preprocessed angiographic images are used for reconstruction. The performance of the technique, in this case, is assessed by means of the projection error, whose average for both views is 7.5%. The reconstruction method is also tested by performing the 3-D reconstruction of a ventriculographic sequence throughout an entire cardiac cycle.