Repositório RCAAP

The studied sector of the central Ribeira Fold Belt (SE Brazil) comprises metatexites, diatexites, charnockites and blastomylonites. This study integrates petrological and thermochronological data in order to constrain the thermotectonic and geodynamic evolution of this Neoproterozoic–Ordovician mobile belt during Western Gondwana amalgamation. New data indicate that after an earlier collision stage at ~610 Ma (zircon, U–Pb age), peak metamorphism and lower crust partial melting, coeval with the main regional high grade D1 thrust deformation, occurred at 572–562 Ma (zircon, U–Pb ages). The overall average cooling rate was low (5 °C/Ma) from 750 to 250 °C (at ~455 Ma; biotite–WR Rb–Sr age), but disparate cooling paths indicate differential uplift between distinct lithotypes: (a) metatexites and blastomylonites show a overall stable 3–5 °C/Ma cooling rate; (b) charnockites and associated rocks remained at T 650 °C during sub-horizontal D2 shearing until ~510–470 Ma (garnet–WR Sm–Nd ages) (1–2 °C/Ma), being then rapidly exhumed/cooled (8–30 °C/Ma) during post-orogenic D3 deformation with late granite emplacement at ~490 Ma (zircon, U–Pb age). Cooling rates based on garnet–biotite Fe–Mg diffusion are broadly consistent with the geochronological cooling rates: (a) metatexites were cooled faster at high temperatures (6 °C/Ma) and slowly at low temperatures (0.1 °C/Ma), decreasing cooling rates with time; (b) charnockites show low cooling rates (2 °C/Ma) near metamorphic peak conditions and high cooling rates (120 °C/Ma) at lower temperatures, increasing cooling rates during retrogression. The charnockite thermal evolution and the extensive production of granitoid melts in the area imply that high geothermal gradients were sustained for a long period of time (50–90 Ma). This thermal anomaly most likely reflects upwelling of asthenospheric mantle and magma underplating coupled with long-term generation of high HPE (heat producing elements) granitoids. These factors must have sustained elevated crustal geotherms for ~100 Ma, promoting widespread charnockite generation at middle to lower crustal levels.

In occupational assessments where workers are exposed to metal dust, the liquid condensate of exhaled breath (EBC) may provide unique indication of pulmonary exposure. The main goal of this study was to demonstrate the quality of EBC to biological monitoring of human exposure. A pilot study was performed in a group of metal dust–exposed workers and a group of nonexposed individuals working in offices. Only metal dust–exposed workers were followed along the working week to determine the best time of collection. Metal analyses were performed with inductively coupled plasma mass spectrometry (ICP-MS). Analytical methodology was tested using an EBC sample pool for several occupationally exposed metals: potassium, chromium, manganese, copper, zinc, strontium, cadmium, antimony, and lead. Metal contents in EBC of exposed workers were higher than controls at the beginning of the shift and remained augmented throughout the working week. The results obtained support the establishment of EBC as an indicator of pulmonary exposure to metals.

Since there are not specific standards for testing direct expansion solar assisted heat pumps for domestic hot water, new testing methodologies are proposed supported by laboratory experiments. Two methodologies were developed for performance measurement: modified BIN method and long term performance prediction with a TRNSYS model validated with specific experimental conditions. The long term performance prediction is a methodology similar to the already obtained for solar thermal systems. A system was tested in Lisbon during one year, covering almost all possible local weather conditions. The hot water tapping test cycle used was in agreement with recent standards EN16147:2011 or EN15316-3-1:2007. The influence of average daily air temperature, dew point temperature and solar irradiation was analysed. The seasonal performance factor was calculated for two cities in Portugal (Lisbon and Porto) and for additional four cities in Europe (Davos, Athens, Helsinki and Strasburg). The establishment of a procedure to calculate the seasonal performance of this kind of systems is very important according to the directive 2009/28/EC of the European Parliament and of the Council.

In the frame of UNISOL project, a test bench was installed to perform tests of a combistore which includes a two-way heat exchanger already submitted to a national patent application. The present work describes the main characteristics of the test bench installed and the tests performed with the objective of optimization of the configuration of the inner storage tank of the combistore (two way heat exchanger), used for DHW pre-heating or as back-up of the space heating. Tests according to EN 12977-3:2012 were performed in order to evaluate distinct configurations of the inner storage tank. Tests according to EN 12977-4:2012 were also performed for characterization of the complete combistore. Long-term performances of solar thermal systems using these combistore are presented. Long-term performance prediction based on testing results according to EN 12977-3:2012, showed how an increased active volume of the heat exchanger enhances the energy available for space heating, although it may decrease solar collector thermal performance and increase the energy losses of the combistore. Long-term performance prediction based on testing results according to EN 12977-4:2012, considering a lower heat loss coefficient since a better insulation of the combistore is expected in future prototypes, showed fsav values for Davos and Wurzburg of 39.3% and 25.3%, respectively.

This paper focuses on the five parameters modeling, consisting on a current controlled generator, single-diode, a shunt and series resistances. Also, a simulation, identification of the parameters for a photovoltaic system and the maximum power point tracking based on VP„g„g is presented. The identification of parameters and the performance of the equivalent circuit model for a solar module simulation are validated by data measured on the photovoltaic modules.

The CO2-assisted autohydrolysis was used for wheat straw treatments at temperatures ranging from 180 to 210 °C and an initial CO2 pressure of 60 bar. The study was performed using three different mixture loadings, such as 250 g of H2O/25 g of wheat straw, 150 g of H2O/15 g of wheat straw and 75 g of H2O/7.5 g of wheat straw. The in situ formed carbonic acid was found to result in a higher dissolution of xylose as well as XOS (xylo-oligosaccharides) in comparison to CO2-free pre-treatments under the same conditions (temperature and LSR). The effect of CO2 concentration was also investigated to address the issue of CO2 involved in the reaction that allows to significantly increase the XOS content. At 210 °C with a mixture loading of 75 g of H2O/7.5 g of wheat straw, XOS were present in the liquor at a concentration of 15.75 g L-1. However, with more severe conditions more degradation products (mainly furfural) were detected (in the liquor and the recovered gas phase from depressurization after the reaction). Glucan was mainly retained in the solid phase (containing up to 64%) together with Klason lignin (maximum dissolution of 18%). The dissolved XOS in the liquid phase are proposed to be used in other applications, either directly, such as prebiotic ingredients, or indirectly, after post-hydrolysis to biofuel production through C5 sugars’ fermentation.

Many bacteria pathogenic to man can interfere in water distribution systems, forming aggregates that give rise to a complex structure called biofilm. In order to monitor the microbiological content of water from beach showers from ten sites along the coast from Lisboa-Carcavelos to Foz do Arelho beaches, 24 water samples were analyzed in 2013, 12 during January and February, and other 12 during June. The samples were collected in 500 mL sterile bottles with sodium thiosulfate. Biofilms were collected on swabs (at the same water sampling points) with transport medium Tween 20, and maintained between 2 ºC and 4 ° C, such as water samples. The following microbiological parameters were investigated for water samples: total microbial count at 22 ºC and 37 ºC, total coliforms and Escherichia coli, Pseudomonas aeruginosa, fecal streptococci, total Staphylococcus and coagulase-positive Staphylococcus. The swabs lead to the isolation of the microorganisms grown on the nutrient agar medium, in order to determine the the same microbiological parameters investigated in water showers. Globally, the water quality was found to be suitable, but that does not rule out the need for constant monitoring of the beach showers. Taking into account that there have been reports of plankton invasions and allergic eruptions after bathing in some seaside spots near Lisboa, these study results prompt us to recommend that swimmers should always shower after bathing or diving since showerheads were found safe all over the coast. 

The functional food market is growing rapidly and membrane processing offers several advantages over conventional methods for separation, fractionation and recovery of bioactive components. The aim of the present studywas to select a process that could be implemented easily on an industrial scale for the isolation of natural lactose-derived oligosaccharides (OS) from caprine whey, enabling the development of functional foods for clinical and infant nutrition. The most efficient process was the combination of a pre-treatment to eliminate proteins and fat, using an ultrafiltration (UF) membrane of 25-kDa molecular weight cutoff (MWCO), followed by a tighter UF membrane with 1-kDaMWCO. circa 90% of the carbohydrates recovered in the final retentate were OS. Capillary electrophoresis was used to evaluate the OS profile in this retentate. The combined membrane-processing system is thus a promising technique for obtaining natural concentrated OS from whey.

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Ca1-xSmxMnO3(0 . x . 0.4) films were successfully fabricated on Indium Tin Oxide (ITO) coated quartzglass substrates by radio frequency magnetron sputtering technique (RF- magnetron sputtering) fromcompacted nanosized powder targets, and subsequent annealing at 800.C in air, for 6 h. X-ray diffrac-tion shows a pure typical perovskite phase for x . 0.1. Scanning electron microscopy and atomic forcemicroscopy revealed that the films surface is dense, with low roughness, depending on the Sm content, even though a few cracks were observed. Crystallite size was found to decrease with the Sm content. Theelectrodes were characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The oxide electrode fs capacitance was estimated using both techniques and the corresponding roughness factors evaluated. The values obtained from the two methods show a good agreement. A com-parison between the voltammetric data and those referred in the literature allowed finding out that theredox reaction occurring at the electrode surface involves the pair Mn4+/Mn3+. EIS measurements con-firm the voltammetric data and they also give additional information about the film porosity and the charge transfer resistance. This last parameter is associated with the oxidation and reduction of the pairMn3+/Mn4+and after normalized by the roughness factor shows an increase with samarium content.

Sustainable production of energy and other added-value products from biomass-derived polysaccharides is a key challenge of an efficient biorefinery facility. Most technologies for biomass processing are energy demanding and use significant amounts of chemicals and catalysts. The need to develop a process which is devoid of all these shortcomings associated with conventional processes is emphasized. A new approach is demonstrated for an integrated wheat straw biorefinery using a green technology, highpressure CO2–H2O, to produce oligosaccharides from hemicellulose fraction and to enhance the cellulose digestibility for the enzymatic hydrolysis. Over the range of reaction conditions (130, 215, 225 °C and 0 to 54 bar of CO2), CO2 adds value to the process by in situ formation of carbonic acid that leads to higher dissolution of hemicellulose into xylo-oligosaccharides and xylose and to the use of less energy in comparison with water-only technologies. Without an additional chemical catalyst, high-pressure CO2–H2O out performed hydrothermal reactions and gave much higher total sugars yield for wheat straw (as high as 84% in comparison with 67.4% with auto-hydrolysis at a 10 °C higher temperature). Apart from the results obtained for valorisation of hemicellulose fraction, both chemical and physical effects of CO2 coupled to enzymatic hydrolysis resulted in a glucan conversion to glucose yield of 82%, which consists of 26% improvement over those obtained during auto-hydrolysis. The influence of the high pressure reaction on the processed solid was examined by spectroscopic methods (namely Scanning Electron Microscopy and Fourier Transform Infrared Spectroscopy). The obtained results suggest that the high pressure CO2-based method is a very promising alternative technology allowing integrated biomass processing within the biorefinery concept.

The high carbon contents and low toxicity levels of chars from coal and pine gasification provide an incentive to consider their use as precursors of porous carbons obtained by chemical activation with K2CO3. Given the chars characteristics, previous demineralization and thermal treatments were made, but no improvement on the solids properties was observed. The highest porosity development was obtained with the biomass derived char (Pi). This char sample produced porous materials with preparation yields near 50% along with high porosity development (ABET 1500 m2 g1). For calcinations at 800 C, the control of the experimental conditions allowed the preparation of samples with a micropore system formed almost exclusively by larger micropores. A mesopore network was developed only for samples calcined at 900 C. Kinetic and equilibrium acetaminophen and caffeine adsorption data, showed that the processes obey to a pseudo-second order kinetic equation and to the Langmuir model, respectively. The results of sample Pi/1:3/800/2 outperformed those of the commercial carbons. Acetaminophen adsorption process was ruled by the micropore size distribution of the carbons. The caffeine monolayer capacities suggest a very efficient packing of this molecule in samples presenting monomodal micropore size distribution. The surface chemistry seems to be the determinant factor that controls the affinity of caffeine towards the carbons.

A design and planning approach is proposed for addressing general multi-period, multi-product closed-loop supply chains (CLSCs), structured as a 10-layer network (5 forward plus 5 reverse flows), with uncertain levels in the amount of raw material supplies and customer demands. The consideration ofa multi-period setting leads to a multi-stage stochastic programming problem, which is handled by amixed-integer linear programming (MILP) formulation. The effects of uncertain demand and supply onthe network are considered by means of multiple scenarios, whose occurrence probabilities are assumed to be known. Several realistic supply chain requirements are taken into account, such as those relatedto the operational and environmental costs of different transportation modes, as well as capacity limitson production, distribution and storage. Moreover, multiple products are considered, which are groupedaccording to their recovery grade. The objective function minimizes the expected cost (that includes facil-ities, purchasing, storage, transport and emissions costs) minus the expected revenue due to the amount of products returned, from repairing and decomposition centers to the forward network. Finally, com-putational results are discussed and analyzed in order to demonstrate the effectiveness of the proposedapproach. Due to the large size of the addressed optimization problem containing all possible scenariosfor the two uncertain parameters, scenario reduction algorithms are applied to generate a representative,albeit smaller, subset of scenarios.

Second order diffusion tensor analysis of diffusion weighted MR data only accounts for a single intra voxel fibre direction. This poses a problem in many regions of the brain where fibres cross. An anisotropy measurement based on the traditional diffusion tensor model, such as fractional anisotropy (FA), produces significantly low values when there are fibres crossing within the same voxel, or in the presence of other partial volume effects. A new anisotropy index based on the variance of the diffusion MRI signal is described and applied to both simulated and experimental data. A method to normalise this parameter, in order to allow comparisons across scan sessions, is also presented. It is shown that this parameter can characterise white matter in situations in which the diffusion tensor formalism fails to accurately reflect the local diffusion. The images obtained show more detail in the fibre structure, a better contrast between regions of high and low anisotropy, and the main fibre tracts appear to be thicker and brighter, which corresponds better anatomically to the information obtained from structural images.

The first steps towards a Monte Carlo simulation method for energy and position corrections in a gas scintillator detector are presented. Recent developments on gas avalanche detectors based on microstructures operating a thigh pressure allow fair detection efficiency for hard X- and gamma-rays. A hybrid system combining an assisted scintillation in a high pressure xenon gas medium and two UV photosensors based on microstructures operating face to face, having the xenon medium sandwiched between them, is under investigation. One of the actual studies is the simulation of the position and amplitude response of the detector and their correction obtained by mapping the detector response. This method can also be applied to solid scintilators.

This work presents the physical and dosimetric properties of the Enhanced Dynamic Wedges (EDW) including depth doses, beam profiles and effective wedge attenuation factors (EWAF) by experimental determinations. The measurements were performed for 6 MV at a Linear accelerator Varian Clinac 2100 C/D, Varian Medical Systems. The main purpose of this work was to study the dosimetric properties of EDW in order to implement them in XiO treatment planning system (TPS) by two algorithms, Clarkson and Convolution/Superpositon under the same conditions.