In this work, coloured glasses were produced based on the synthesis of gold and silver nanoparticles by the sol-gel process having in mind their application in art works. Gold and silver were used separately or as a mixture by varying the mole fractions in order to get a range of colours from yellow to red. The gold and silver nanoparticles were prepared by the reduction of tetrachloroauric acid and silver nitrate with sodium citrate in aqueous solutions which were further introduced in the sol-gel system. Attention was focused on the thermal treatment of the sol-gel samples. Different temperatures were used in order to determine their influence on the obtained colour. The glasses were characterized by UV-Vis absorption spectroscopy and the size of the nanoparticles was examined by transmission electron microscopy (TEM). The range of colours mentioned above is obtained either by preparing nanoparticles of each metal and mixing them or by preparing nanoparticles from solutions containing initially ions of both metals. In the former case, two surface plasmon resonance (SPR) bands were observed for temperatures below 200 degrees C while higher temperatures promote the formation of alloys between the Ag and Au nanoparticles. In the latter case, only one SPR band is observed and the nanoparticle size distribution is narrower. The results were explained by nanoparticle aggregation promoted by temperature. Glasses containing only Ag did not present the typical yellow colour above 300 degrees C but it was shown that the colour could be stabilized if Au was added in small amounts (Au/Ag molar ratio 0.1). (C) 2010 Elsevier B.V. All rights reserved.

In moderately acidic water/ethanol solutions, 7-(naphthalen-2-ylmethyl)-5,6-dihydrobenzo[c]xanthen12-ium perchlorate shows C-H proton acidity giving rise to an ethylenic base species, instead of the hydration products of the typical flavylium network of chemical reactions, hemiketal, cis-chalcone and trans-chalcone. The kinetics of this acid-base process is much slower, k(obs)(s(-1)) = 3.5 x 10(-3) + 0.16[H(+)], than those commonly observed for O-H deprotonation. In the presence of the triblock copolymer Pluronic F-127, the ethylenic base is dramatically stabilized shifting the pK(a) from 1.35 (in ethanol : water (1 : 1) to -0.35. Taking profit from the well-described temperature dependence of this polymer, a phase transition thermochromic system was achieved. The system was cycled between 5 and 35 degrees C with negligible changes in absorbance after 20 cycles.

New trans-2-hydroxychalcones bearing a carboxylate group at position 2' (Ct(-)) were synthesized (compounds 2 and 3). These compounds lead to a network of chemical reactions depending on pH value, light, and solvent. In water, when the pH value is lowered, the ionized trans-chalcone is protonated and the flavylium cation AH(+) is formed at very acidic pH values through hemiketal B and cis-chalcone Cc, with global acidity constants of pK'(a) <= -1 and approximate to 0.1, respectively, for 2 and 3. The electron-acceptor character of the carboxylic substituent not only increases the observed acidity of the flavylium cation, but also decreases the rate of the ring-opening/closing from a subsecond timescale to hours relative to model compound 1 (without carboxylate). The photochemistry of the network was studied in detail by means of continuous irradiation, monitored by UV/Vis absorption and H-1 and C-13 NMR spectroscopic analysis. Although compound 3 is only slightly photoactive, compound 2 (Ct(-)) reacts in aqueous solutions (lambda(irr) = 313 nm) to form B- and Cc(-), with a global quantum yield of 0.15, and fully reverts back to Ct(-) with a rate constant of k = 6.7 x 10(-5) s(-1). The flavylium cation is no longer formed in methanol, and irradiation of Ct(-) leads to the formation of B- and the new lactone-trapped chromene species La. The formation of La takes place through a sequence of three photochemical steps: photoisomerization of Ct(-), photo-ring-closing reaction of Cc , and photolactonization of B-. Only the cis/trans isomerization and ring-closing reactions are thermally reversible on a timescale of seconds and hours, respectively. A photochromic system was achieved in rigid matrices of methanol (at 77 K) and 1-dodecanol (5 degrees C) by irradiating lactone La to give a red ortho-quinone allide through a photo-ring-opening reaction; the color disappears with a rate constant of k = 1.25 x 10(-2) s(-1) in 1-dodecanol at 5 degrees C.

A symmetric bis(flavylium) constituted by two 7-hydroxyflavylium moieties linked by a methylviologen bridge was synthesized. The thermodynamic and kinetics of the network of chemical reactions involving bis(flavylium) and the model compound 7-hydroxy-4'-methylflavylium was completely characterized by means of direct and reverse pH jumps (stopped flow) and flash photolysis. Both compounds follow the usual pH-dependent network of chemical reactions of flavylium derivatives. The equilibrium species of the model compound are the flavylium cation (acidic species) and the trans-chalcone (basic species) with an apparent pK(a)' = 2.85. In the case of the bis(flavylium) it was possible to characterize by (1)H NMR spectroscopy three species with different degrees of isomerization: all flavylium, flavylium-trans-chalcone, and all trans-chalcone. Representation of the time-dependent mole fraction distribution of these three forms after a pH jump from equilibrated solutions of all-flavylium cation (lower pH values) to higher pH values, shows that formation of trans-chalcone is not completely stochastic (two independent isomerizations), the isomerization of one flavylium showing a small influence on the isomerization of the other. The radical of the methyl viologen bridge is formed upon reduction of the bis(trans-chalcone) with dithionite. The system is reversible after addition of an oxidant in spite of the occurrence of some decomposition.

All the buildings promote impacts on the environmental and in human health who impose more attention in the evaluation of sustainable performance in building design. The difficulty to identify the better design process to answer to all conflicting factors in special the economical and environmental performance impose the research of the issue. To assist the research in the way to find the best process to the promotion of design alternatives the life cycle analysis methodology is the more adapted the deal with all the three factors of sustainable development. The promotion of a new process to design phase of green build is the goal of this paper.

The use of indicators to measure sustainability in urban development’s is the most efficient tool to help local authorities in the regulation of new and existing urban areas. The demographic grow in developing countries impose a utilization of a tool who make possible have a clear image of the process of land use change and the evaluation of the capacity of charge is the way to archive a effective sustainable development of the urban areas and regions. The selection of the correct indicators to apply to the process of land use transformation in Cabo Verde is the objective of the paper.

The urban sprawl phenomenon has been raise in the last three decades. In the same time all municipalities have adopted the methodology of the master planning to program the land use. In the same time the well-being in cities have decreased and the life quality of population is dreadful so is urgent the promotion of a new process to planning the transformation of existing urban areas and program new areas. The aim of this paper is the proposal of a new process to be adopted to the master planning.

The use of cellulosic fibers as load bearing constituents in composite materials has increased over the last decade due to their relative cheapness compared to conventional materials such as glass and aramid fibers, their ability to recycle, and because they compete well in terms of strength per weight of material. All-cellulosic based composites prepared from cellulose derivatives based matrices and microcrystalline cellulosic fibers made by direct coupling between fibers and matrix present interesting mechanical and gas permeation properties, thus being potential candidates for packaging materials. Both the cellulosic matrix and the reinforcing fibers are biocompatible and widely used in the pharmaceutical industry, which is very important for the envisaged application. In addition to their biocompatibility, cellulosic systems have the ability to form both thermotropic and lyotropic chiral nematic phases, and the composites produced from the latter show improved mechanical properties due to fiber orientation induced by the anisotropic matrix. The preparation and characterization (morphological, topographical, mechanical, gas barrier properties) of all-cellulosic based composites are described in this chapter.

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Gene knock-out studies on Geobacter sulfurreducens cells showed that the periplasmic triheme cytochrome PpcA is involved in respiratory pathways leading to the extracellular reduction of Fe(III) and U(VI) oxides. The crucial role of this protein in bridging the electron transfer between the cytoplasm and cell exterior was further supported by proteomics studies. In comparison with non-heme proteins, the presence of numerous proton-containing groups in the heme groups causes additional challenges to the full protein assignment and structure calculation. Here, we report the complete assignment of the heme proton signals together with the 1H and 15N backbone and side chain assignments of the reduced form of PpcA.

Previous studies with Geobacter sulfurreducens have demonstrated that OmcS, an abundant c-type cytochrome that is only loosely bound to the outer surface, plays an important role in electron transfer to Fe(III) oxides as well as other extracellular electron acceptors. In order to further investigate the function of OmcS, it was purified from a strain that overproduces the protein. Purified OmcS had a molecular mass of 47 015 Da, and six low-spin bis-histidinyl hexacoordinated heme groups. Its midpoint redox potential was −212 mV. A thermal stability analysis showed that the cooperative melting of purified OmcS occurs in the range of 65–82 °C. Far UV circular dichroism spectroscopy indicated that the secondary structure of purified OmcS consists of about 10% α-helix and abundant disordered structures. Dithionite-reduced OmcS was able to transfer electrons to a variety of substrates of environmental importance including insoluble Fe(III) oxide, Mn(IV) oxide and humic substances. Stopped flow analysis revealed that the reaction rate of OmcS oxidation has a hyperbolic dependence on the concentration of the studied substrates. A ten-fold faster reaction rate with anthraquinone-2,6-disulfonate (AQDS) (25.2 s− 1) was observed as compared to that with Fe(III) citrate (2.9 s− 1). The results, coupled with previous localization and gene deletion studies, suggest that OmcS is well-suited to play an important role in extracellular electron transfer.

Currently, there is high energy consumption in the buildings sector, in Portugal, which implies
an obstacle to the accomplishment of purposes intrinsic to the assumptions of sustainable development
and construction.
Therefore, efforts should be made to allow the construction of energy efficient buildings,
which is based on the adoption of a set of passive and/or active techniques that strive to reduce the
energy consumption of buildings throughout its life cycle, while ensuring comfort for its occupants.
The main objective of this dissertation is to evaluate passive and active proposals for
improving energy efficiency in residential buildings, based on the calculation of energy savings
associated with air conditioning and the payback period. To this end it was established a case study,
using as a base model a building unit of a multifamily building. The initial assessment of energetic
performance of this case study and its comparison after the implementation of improvement strategies
was done through a dynamic analysis using the EnergyPlus software.
The following solutions were evaluated: application of thermal insulation inside the cavity
wall, application of ETICS, more efficient glazing solutions, changing the building's solar orientation,
fixed shading devices application, definition of a pattern of night ventilation in the summer and use of
more efficient electrical equipment and lighting.
It was found that the use of these systems improves the energy efficiency of buildings, such as
the case study, despite of having different payback periods.