Histological analysis of the alterations on cortical bone channels network after radiotherapy: A rabbit study

The aim of this study was to evaluate the effects of radiotherapy in cortical bone channels network. Fourteen rabbits were divided in two groups and test group received single dose of 15 Gy cobalt‐60 radiation in tibia, bilaterally. The animals were sacrificed and a segment of tibia was removed and histologically processed. Histological images were taken and had their bone channels segmented and called regions of interest (ROI). Images were analyzed through developed algorithms using the SCILAB mathematical environment, getting percentage of bone matrix, ROI areas, ROI perimeters, their standard deviations and Lacunarity. The osteocytes and empty lacunae were also counted. Data were evaluated using Kolmogorov‐Smirnov, Mann Whitney, and Student's t test (P < 0.05). Significant differences in bone matrix percentage, area and perimeters of the channels, their respective standard deviations and lacunarity were found between groups. In conclusion, the radiotherapy causes reduction of bone matrix and modifies the morphology of bone channels network. Microsc. Res. Tech. 73:1015–1018, 2010. © 2010 Wiley‐Liss, Inc.     

Using multiobjective evolutionary algorithms in the optimization of operating conditions of polymer injection molding

A Multiobjective Optimization Genetic Algorithm, denoted as Reduced Pareto Set Genetic Algorithm with Elitism (RPSGAe), has been applied to the optimization of the polymer injection molding process. The aim is to implement an automatic optimization scheme capable of defining the values of important process operating conditions (such as melt and mould temperatures, injection time, and holding pressure), yielding the best performance in terms of prescribed criteria (such as temperature difference on the molding at the end of filling, the maximum cavity pressure, the pressure work, the volumetric shrinkage and the cycle time). The methodology proposed was applied to some case studies. The results produced have physical meaning and correspond to a successful process optimization. POLYM. ENG. SCI., 50:1667–1678, 2010. © 2010 Society of Plastics Engineers     

Modelling line-of-sight coupled MIMO systems with generalised scattering matrices and spherical wave translations

A model to rigorously characterise line-of-sight MIMO systems is introduced. It is based on the generalised scattering matrix of each antenna, considered as isolated, and the rotation and translation coefficients of spherical modes. The resulting channel matrix rigorously includes the exact spherical vector nature of electromagnetic propagation (which may exert a significant influence over short-range links), mutual coupling effects and real antenna reflection, transmission, reception and scattering features. Numerical results are presented for MIMO systems made up of ideal dipoles.     

Characterization of beef tallow biodiesel and their mixtures with soybean biodiesel and mineral diesel fuel

Tallow is a raw material for biodiesel production that, due to their highly centralized generation in slaughter/processing facilities and historically low prices, may have energy, environmental, and economic advantages that could be exploited. However beef tallow biodiesel have unfavorable properties due the presence of high concentration of saturated fatty esters. One way to overcome these inconveniences is using blending procedures. In this way, blends of beef tallow biodiesel with soybean biodiesel and with conventional mineral diesel fuel were prepared and the quality of the mixtures was monitored with the purpose to study ideal proportions of the fuels. By measurement of the viscosity, density, cold filter plugging point, and flash point, it was demonstrated that tallow biodiesel can be blended with both mineral diesel and soybean biodiesel to improve the characteristics of the blend fuels, over that of the tallow.     

Study on the Microstructure and Liquid Phase Formation in a Semisolid Gray Cast Iron

The development of high-quality semisolid raw materials requires an understanding of the phase transformations that occur as the material is heated up to the semisolid state, i.e., its melting behavior. The microstructure of the material plays a very important role during semisolid processing as it determines the flow behavior of the material when it is formed, making a thorough understanding of the microstructural evolution essential. In this study, the phase transformations and microstructural evolution in Fe2.5C1.5Si gray cast iron specially designed for thixoforming processes as it was heated to the semisolid state were observed using in situ high-temperature confocal laser scanning microscopy. At room temperature, the alloy has a matrix of pearlite and ferrite with fine interdendritic type D flake graphite. During heating, the main transformations observed were graphite precipitation inside the grains and at the austenite grain boundaries; graphite flakes and graphite precipitates growing and becoming coarser with the increasing temperature; and the beginning of melting at around 1413 K to 1423 K (1140 °C to 1150 °C). Melting begins with the eutectic phase (i.e., the carbon-rich phase) and continues with the primary phase (primary austenite), which is consumed as the temperature increases. Melting of the eutectic phase composed by coarsened interdendritic graphite flakes produced a semi-continuous liquid network homogeneously surrounding and wetting the dendrites of the solid phase, causing grains to detach from each other and producing the intended solid globules immersed in liquid.     

Sparse Representations for Image Decompositions

International Journal of Computer Vision - We are given an image I and a library of templates ${\mathcal{L}}$ , such that ${\mathcal{L}}$ is an overcomplete basis for I. The templates can...     

Ejection force of tubular injection moldings. Part II: A prediction model

The integrated knowledge of the injection molding process and the material changes induced by processing is essential to guarantee the quality of technical parts. In the case of parts with deep cavities, quite often the ejection phase of the molding cycle is critical. Thus, in the mold design stage, the aspects associated with the ejection system will require special consideration. In particular, the prediction of the ejection force will contribute to optimizing the mold design and to guarantee the integrity of the moldings. In this work, a simulation algorithm based on a thermomechanical model is described and their predictions are compared with experimental data obtained from a fully‐instrumented mold (pressure, temperature, and force). Three common thermoplastics polymers were used for the tubular moldings: a semicrystalline polypropylene and two amorphous thermoplastics: polystyrene and polycarbonate. The thermomechanical model is based on the assumption of the polymer behavior changing from purely viscous to purely elastic below a transition point. This point corresponds to solidification determined by temperature in the case of amorphous materials and by critical crystallinity for semicrystalline polymers. The model results for the ejection force closely agree with the experimental data for the three materials used. POLYM. ENG. SCI. 45:325–332, 2005. © 2005 Society of Plastics Engineers.     

Adapting the Olgyay bioclimatic chart to assess local thermal comfort levels in urban regions

Clean Technologies and Environmental Policy - Providing comfortable thermal conditions for users of open spaces is vitally important for improving the quality of urban life. Thermal comfort can be...     

Solubility and dissolution performances of spray-dried solid dispersion of Efavirenz in Soluplus

Abstract

Efavirenz (EFV), a first-line anti-HIV drug largely used as part of antiretroviral therapies, is practically insoluble in water and belongs to BCS class II (low solubility/high permeability). The aim of this study was to improve the solubility and dissolution performances of EFV by formulating an amorphous solid dispersion of the drug in polyvinyl caprolactam–polyvinyl acetate–polyethylene glycol graft copolymer (Soluplus^®) using spray-drying technique. To this purpose, spray-dried dispersions of EFV in Soluplus^® at different mass ratios (1:1.25, 1:7, 1:10) were prepared and characterized using particle size measurements, SEM, XRD, DSC, FTIR and Raman microscopy mapping. Solubility and dissolution were determined in different media. Stability was studied at accelerated conditions (40?°C/75% RH) and ambient conditions for 12 months. DSC and XRD analyses confirmed the EFV amorphous state. FTIR spectroscopy analyses revealed possible drug–polymer molecular interaction. Solubility and dissolution rate of EFV was enhanced remarkably in the developed spray-dried solid dispersions, as a function of the polymer concentration. Spray-drying was concluded to be a proper technique to formulate a physically stable dispersion of amorphous EFV in Soluplus^®, when protected from moisture.     

Construction and qualitative assessment of a bibliographic portfolio using the methodology Methodi Ordinatio

Methodi Ordinatio is a methodology used to accomplish systematic literature reviews, to build bibliographical portfolios, and to map the state of the art of a research theme. It is composed of nine phases. The 7th phase, named InOrdinatio, applies an equation that orders the papers according to its scientific relevance. The equation applies the alpha (α) element, which can vary from 0 to 10 depending on the research need of currentness and according to the researcher’s perception for its variation. Therefore, the aim of this paper is to test and analyse the variations of the alpha (α) values in the equation InOrdinatio and its influence in the qualification of the items that composes a portfolio. In order to reach this purpose, a practical application was performed and a bibliographic portfolio on the theme Horizontal Business Networks and Trust was built. Using the data from the bibliographic portfolio, the alpha values from 0 to 10 were applied and their influence on the final qualification of the articles was analysed. As a complementary objective, the areas where the methodology was successfully applied until now are also identified. The results show that the methodology is coherent, reproducible and useful to sort the most relevant articles in accordance with what is internationally recognized as valid scientific criteria: the impact factor, year of publication, and number of citations.