Improvement of the thermal behaviour of gypsum blocks by the incorporation of microcapsules containing PCMS obtained by suspension polymerization with an optimal core/coating mass ratio

The feasibility of incorporating microcapsules containing Phase Change Materials (PCMs), previously obtained by a suspension polymerization process, in gypsum wallboards to increase the wall energy storage capacity was studied. Firstly, the energy storage capacity of the resulting microcapsules and the microencapsulation efficiency was maximized by studying the influence of the synthesis variable core/coating mass ratio on the suspension polymerization process. Results indicate that the higher paraffin wax to styrene monomer mass ratio, the lower microencapsulation efficiency. A mass ratio of Rubitherm® RT27 to styrene monomer equal 1.5 allowed to obtain microcapsules with the highest energy storage capacity and a good microencapsulation efficiency. It was also observed that the energy storage capacity is dependent on the particle size; the maximum capacity was obtained for a particle size of 500 μm. Finally, the thermal behaviour of three gypsum wallboards one without PCMs and the others doped with 4.7% and 7.5% by weight of microcapsules containing Rubitherm® RT27 at the optimal core/coating mass ratio was studied. Results showed that the higher the amount of microcapsules containing PCMs incorporated to the gypsum wallboard, the lower or higher the external wall temperature for heating or cooling process, respectively. Besides, the incorporation of the microcapsules to the wall increased the time required to achieve the final steady state, verifying that the material insulation capacity was enhanced by increasing PCMs content in the wall.     

Oxidative processes of desulfurization of liquid fuels

Environmental concerns have introduced a need to remove sulfur‐containing compounds from light oil. As oxidative desulfurization is conducted under very mild reaction conditions, much attention has recently been devoted to this process. In this contribution, the developments in selective removal of organosulfur compounds present in liquid fuels via oxidative desulfurization, including both chemical oxidation and biodesulfurization, are reviewed. At the end of each section, a brief account of the research directions needed in this field is also included. Copyright © 2010 Society of Chemical Industry     

Novel clay‐based nanobiocomposites of biopolyesters with synergistic barrier to UV light,gas, and vapour

This article presents novel solvent cast biocomposites of poly(lactic acid) (PLA), polyhydroxybutyrate‐co‐valerate (PHBV), and polycaprolactone (PCL) with enhanced barrier properties to UV light, oxygen, water, and limonene by means of incorporating an organomodified mica‐based clay grade. The TEM results suggested a good clay dispersion but with no exfoliation in the three biopolyesters. In agreement with the crystallinity data, which was found to generally increase with increasing filler content, oxygen but specially water and d ‐limonene permeability coefficients were seen to decrease to a significant extent in the biocomposites and an optimum property balance was found for 5 wt % of clay loading in the three biopolymers. With increasing clay content, the light transmission of these biodegradable biocomposites decreased by up to 90% in the UV wavelength region due to the specific UV blocking nature of the clay used. As a result, these new biocomposites can have significant potential to develop packaging films, coatings and membranes with enhanced gas and vapor barrier properties and UV blocking performance. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Spectroscopic and thermal contribution to the structural characterization of vandenbrandeite

The vibrational (IR and Raman) spectrum of Vandenbrandeite, Cu[UO₂(OH)₄], has been recorded and discussed on the basis of structural considerations through the use of empirical expressions. As the H-bonding in the lattice is poorly known, the characteristics of this bond has been analyzed with the aid of H/D isotope exchange, thermal assays and electron microscopy. Samples are practically amorphous to XRD up to 700°C whereas crystals morphologically different by SEM microscopy and well characterized by XRD technique are observed from 800°C. Vibrational spectroscopy reveals that the atomic arrangement in the structure remains largely unaffected as the dehydration proceeds, suggesting a topochemically controlled process. EPR spectroscopy suggests a disordered distribution of Cu(II) ions as temperature increases. Finally, thermal dehydroxylation and paragenesis of the copper-uranyl oxide hydrate are correlated.     

Automatic cataloguing of advertisement in magazines

Advertising activities are one of the main aspects of companies. Its global evaluation is an important index, not only within economic sectors, but also for public economic policies. The evaluation of the adverts is carried out by specialised companies, which deliver advertisement expenditure information. Their work consist in an exhaustive collection of adverts (e.g., all adverts from any media), and deliver information (integrated from every media) relevant for their clients. The delivered information can range from statistical data to bear witness of an advertisement campaign. Important quality indicators for the delivered information are the exhaustiveness, the delay of delivering and a correct identification of different versions of an advert. In this article, we present an advanced computer-aided system for collecting and delivering advertising information from magazines and daily press. The system provides computer-aided data validation and exploitation resources. Using computerised document image analysis and image database indexing and retrieval, the system is able to locate an advert in a page, extract relevant quality indicators and search the advert (or similar ones) in a database. This tool is configured as an intranet and offers resources for image data acquisition, storage/retrieval and advert quality indicators extraction, however, the key of the system is the underlying idea of incorporating computer-aided visual information management.The EU has funded the system construction within the program: European Take-up of essential Information Society Technologies, Integrated Machine Vision (EUTIST-IMV), task CV-AdControl. .     

Modified Kostiakov Infiltration Function: Accounting for Initial and Boundary Conditions

The effect of specific initial and boundary conditions is generally not considered when applying the Kostiakov infiltration functions. A methodology is developed to account for changes in water levels and initial soil moisture. First, Richards’ equation is solved numerically to generate a database of one-dimensional infiltration values, with varying initial (water content or pressure head) and boundary (ponding depth) conditions for three contrasting soils. These are then used to calibrate corresponding coefficients for modified Kostiakov models and, by considering linear regressions, to obtain simple correction factors. Results show that the correction factors are not universally valid, and only the correction to the Kostiakov k parameter shows statistically consistent applicability. However, examples demonstrate potentially significant improvement in the accuracy of irrigation models by correcting the Kostiakov equation to account for initial and boundary conditions.     

Sustainable Development and the Sustainability of Competitive Advantage: A Dynamic and Sustainable View of the Firm

Does the need for sustainable development hinder businesses’ ability to create value? Is a firm’s competitiveness negatively affected by considering that need? After quickly reviewing the main literature contributions on the relationship between business and society, and drawing from resource‐based view of the firm and sustainable development literature, this paper presents a proposal for a dynamic and sustainable view of the firm. It shows how considering the changes introduced into the competitive landscape by sustainable development influences the way in which companies develop their resources, capabilities and activities, fostering the persistence of competitive advantages based on knowledge and innovation.     

GaAs-based modulation-doped quantum-well infrared photodetectors for single- and two-color detection in 3-5 /spl mu/m

Double-barrier quantum-well infrared photodetectors are promising for operation in the midinfrared region. In this paper, we present a series of novel molecular beam epitaxy (MBE)-grown devices based on modulation-doped (MD) AlGaAs-AlAs-GaAs structures that exhibit a remarkable responsivity at zero bias (0.05 A/W) at 4.6 /spl mu/m. Since the photovoltaic properties are strongly dependent on the symmetry of the potential profile, we have systematically varied the position of the dopant in the barriers for a series of single-color detectors. Low-temperature photocurrent spectra and current-voltage (I-V) characteristics (in the dark and under illumination) show that the location of the dopant is a relevant design parameter, due to its role in the photovoltaic behavior (i.e., the presence or absence of zero bias signal). The performance of the MD devices is compared with that of a detector with doping in the center of the well and otherwise the same structure. In particular, the responsivity and detectivity seem to be higher for the MD detectors than for well-doped samples, especially when the dopant is located in the barrier closest to the substrate. Therefore, we have chosen that MD dopant profile when designing and growing, to our knowledge, the first 3-5 /spl mu/m two-color detector, with simultaneous detection at 3.8 and 4.4 /spl mu/m.     

Classification of a bacterial isolate, from pozol, exhibiting antimicrobial activity against several gram-positive and gram-negative bacteria, yeasts, and molds

A bacterial isolate, designated CS93, capable of producing a broad-spectrum antimicrobial compound(s) effective against gram-positive and gram-negative bacteria, yeasts, and molds was isolated from pozol, a fermented maize product. This strain was phenotypically similar to another pozol isolate that was previously designated as Agrobacterium azotophilium by other investigators. By using biochemical, phenotypic, and 16S rRNA sequence analysis, both pozol isolates were identified as members of the genus Bacillus, possibly a variant of Bacillus subtilis. While the antimicrobial compound(s) was initially produced only on a solid medium, parameters were identified for production in broth. The compound(s) was heat stable (121 degrees C for 15 min), exhibited activity over a wide pH range (pH 3 to pH 11), and was inactivated by pronase E. The antimicrobial compound(s) was bactericidal and bacteriolytic against Escherichia coli V517, bacteriostatic against Micrococcus luteus, and fungistatic against Saccharomyces cerevisiae. The inhibitory compound(s) could possibly serve as a food biopreservative.