Avaliação do desempenho energético de uma pequena fracção de serviços existente tendo por base as metodologias regulamentares do RSECE e do RECS

A dependência energética das grandes economias mundiais, alertaram o mundo para a necessidade de mudar o comportamento relativo ao consumo de energia. O sector dos edifícios representa 40% dos consumos globais de energia na União Europeia, já no panorama nacional, o sector dos edifícios representa 28% dos consumos globais da energia, constituindo uma parte significativa no consumo global de energia, sendo portanto, essencial avaliar o desempenho energético dos edifícios, no sentido de promover a sua eficiência energética e beneficiar do grande potencial de economia de energia. Portugal à luz das linhas de orientação da União Europeia com o objectivo de instigar o aumento da eficiência energética nos edifícios, lançou o programa nacional para a eficiência energética nos Edifícios (P3E). Posteriormente, da transposição da Directiva 2002/91/CE para a ordem jurídica nacional surgiu o SCE, o RCCTE e o RSECE. Já em 2013, com a necessidade de transpor para a ordem da jurídica nacional a Directiva n.º 2010/31/EU, surge o Decreto-Lei n.º 118/2013, reunindo num só diploma o SCE, o REH e o RECS, promovendo uma revisão da legislação nacional, garantindo e promovendo a melhoria do desempenho energético dos edifícios. Através da presente dissertação, pretende-se avaliar o desempenho energético de uma pequena fracção de serviços existente tendo por base a metodologia regulamentar revogada do RSECE e a vigente metodologia regulamentar do RECS. Após apresentação dos dois regulamentos e da identificação das principais diferenças entre as duas metodologias regulamentares, procedeu-se ao enquadramento da fracção em estudo no âmbito de aplicação do RSECE e do RECS. Segundo os dois regulamentos a fracção não está sujeita a requisitos mínimos de qualidade térmica, nem a quaisquer requisitos energéticos e de eficiência dos sistemas técnicos, ao tratar-se de uma pequena fracção de serviços existente. Recorrendo ao software DesignBuilder, gerou-se o modelo da fracção em estudo, que através da simulação dinâmica multizona permitiu obter os consumos de energia anuais e a sua desagregação por utilização final. A partir dos consumos energia, determinaram-se os indicadores de eficiência energética de acordo com as duas metodologias, permitindo deste modo, proceder à classificação energética da fracção em estudo. De acordo com o RSECE a fracção em estudo obteve a classificação D, já segundo o RECS alcançou a classe C. Para aumentar a eficiência energética da fracção e consequentemente diminuir o consumo energético, foi proposto proceder à substituição das lâmpadas existentes por lâmpadas tubulares de tecnologia LED e à substituição do sistema de ventilação mecânico por um sistema de ventilação dimensionado para os novos valores de caudal de ar novo regulamentares. Com a implementação destas duas medidas a fracção em estudo melhoraria a sua classificação energética, exigindo um investimento baixo e apresentando um período de retorno de 1 ano e 5 meses. Segundo o RSECE passaria para a classe B, e aplicando a metodologia regulamentar do RECS alcançaria a classe B-.

Cloud base height and cosmic rays

Cosmic rays modify current flow in the global atmospheric electrical circuit. Charging at horizontal layer cloud edges has been observed to be consistent with global circuit vertical current flow through the cloud, which can modify the properties of small and pure water droplets. Studies have been hampered by the absence of cloud edge observations, hence cloud base height information is investigated here. Cloud base height measured at the Lerwick Observatory, Shetland, UK, is analysed using threshold tests and spectral analysis. The cloud base height distributions for low cloud (cloud base less than 800 m) are found to vary with cosmic ray conditions. Further, 27 day and 1.68 year periodicities characteristic of cosmic ray variations are present, weakly, in the cloud base height data of stratiform clouds, when such periodicities are present in neutron monitor cosmic ray data. These features support the idea of propagation of heliospheric variability into layer clouds, through the global atmospheric electric circuit.

Ice Shelf Water plume flow beneath Filchner-Ronne Ice Shelf, Antarctica

[1] A two-dimensional plume model is used to study the interaction between Filchner-Ronne Ice Shelf, Antarctica and its underlying ocean cavity. Ice Shelf Water (ISW) plumes are initiated by the freshwater released from a melting ice shelf and, if they rise, may become supercooled and deposit marine ice due to the pressure increase in the in situ freezing temperature. The aim of this modeling study is to determine the origin of the thick accretions of marine ice at the base of Filchner-Ronne Ice Shelf and thus improve our understanding of ISW flow paths. The model domain is defined from measurements of ice shelf draft, and from this ISW the model is able to predict plumes that exit the cavity in the correct locations. The modeled plumes also produce basal freezing rates that account for measured marine ice thicknesses in the western part of Ronne Ice Shelf. We find that the freezing rate and plume properties are significantly influenced by the confluence of plumes from different meltwater sources. We are less successful in matching observations of marine ice under the rest of Filchner-Ronne Ice Shelf, which we attribute primarily to this model’s neglect of circulations in the ocean outside the plume.

Flow injection analysis using carbon film resistor electrodes for amperometric determination of ambroxol

Flow injection analysis (FIA) using a carbon film sensor for amperometric detection was explored for ambroxol analysis in pharmaceutical formulations. The specially designed flow cell designed in the lab generated sharp and reproducible current peaks, with a wide linear dynamic range from 5 x 10(-7) to 3.5 x 10(-4) mol L-1, in 0.1 mol L-1 sulfuric acid electrolyte, as well as high sensitivity, 0.110 A mol(-1) L cm(-2) at the optimized flow rate. A detection limit of 7.6 x 10(-8) mol L-1 and a sampling frequency of 50 determinations per hour were achieved, employing injected volumes of 100 mu L and a flow rate of 2.0 mL min(-1). The repeatability, expressed as R.S.D. for successive and alternated injections of 6.0 x 10(-6) and 6.0 x 10(-5) mol L-1 ambroxol solutions, was 3.0 and 1.5%, respectively, without any noticeable memory effect between injections. The proposed method was applied to the analysis of ambroxol in pharmaceutical samples and the results obtained were compared with UV spectrophotometric and acid-base titrimetric methods. Good agreement between the results utilizing the three methods and the labeled values was achieved, corroborating the good performance of the proposed electrochemical methodology for ambroxol analysis. (C) 2008 Elsevier B.V. All rights reserved.

Novos sistemas de liberação de fármacos à base de xilana

The aim of this work was to perform the extraction and characterization of xylan from corn cobs and prepare xylan-based microcapsules. For that purpose, an alkaline extraction of xylan was carried out followed by the polymer characterization regarding its technological properties, such as angle of repose, Hausner factor, density, compressibility and compactability. Also, a low-cost and rapid analytical procedure to identify xylan by means of infrared spectroscopy was studied. Xylan was characterized as a yellowish fine powder with low density and poor flow properties. After the extraction and characterization of the polymer, xylan-based microcapsules were prepared by means of interfacial crosslinking polymerization and their characterization was performed in order to obtain gastroresistant multiparticulate systems. This work involved the most suitable parameters of the preparation of microcapsules as well as the study of the process, scale-up methodology and biological analysis. Magnetic nanoparticles were used as a model system to be encapsulated by the xylan microcapsules. According to the results, xylan-based microcapsules were shown to be resistant to several conditions found along the gastrointestinal tract and they were able to avoid the early degradation of the magnetic nanoparticles

Micropartículas poliméricas à base de xilana e Eudragit® S-100 contendo mesalazina visando à liberação cólon-específica

Colon-specific drug delivery systems have attracted increasing attention from the pharmaceutical industry due to their ability of treating intestinal bowel diseases (IBD), which represent a public health problem in several countries. In spite of being considered a quite effective molecule for the treatment of IBD, mesalazine (5-ASA) is rapidly absorbed in the upper gastrointestinal tract and its systemic absorption leads to risks of adverse effects. The aim of this work was to develop a microparticulate system based on xylan and Eudragit® S- 100 (ES100) for colon-specific delivery of 5-ASA and evaluate the interaction between the polymers present in the systems. Additionaly, the physicochemical and rheological properties of xylan were also evaluated. Initially, xylan was extracted from corn cobs and characterized regarding the yield and rheological properties. Afterwards, 10 formulations were prepared in different xylan and ES100 weight ratios by spray-drying the polymer solutions in 0.6N NaOH and phosphate buffer pH 7.4. In addition, 3 formulations consisting of xylan microcapsules were produced by interfacial cross-linking polymerization and coated by ES100 by means of spray-drying in different polymer weight ratios of xylan and ES100. The microparticles were characterized regarding yield, morphology, homogeneity, visual aspect, crystallinity and thermal behavior. The polymer interaction was investigated by infrared spectroscopy. The extracted xylan was presented as a very fine and yellowish powder, with mean particle size smaller than 40μm. Regarding the rheological properties of xylan, they demonstrated that this polymer has a poor flow, low density and high cohesiveness. The microparticles obtained were shown to be spherical and aggregates could not be observed. They were found to present amorphous structure and have a very high thermal stability. The yield varied according to the polymer ratios. Moreover, it was confirmed that the interaction between xylan and ES100 occurs only by means of physical aggregation

Um algoritmo para estimação de estado em alimentadores de distribuição de energia elétrica com base no método da soma de potências

Most algorithms for state estimation based on the classical model are just adequate for use in transmission networks. Few algorithms were developed specifically for distribution systems, probably because of the little amount of data available in real time. Most overhead feeders possess just current and voltage measurements at the middle voltage bus-bar at the substation. In this way, classical algorithms are of difficult implementation, even considering off-line acquired data as pseudo-measurements. However, the necessity of automating the operation of distribution networks, mainly in regard to the selectivity of protection systems, as well to implement possibilities of load transfer maneuvers, is changing the network planning policy. In this way, some equipments incorporating telemetry and command modules have been installed in order to improve operational features, and so increasing the amount of measurement data available in real-time in the System Operation Center (SOC). This encourages the development of a state estimator model, involving real-time information and pseudo-measurements of loads, that are built from typical power factors and utilization factors (demand factors) of distribution transformers. This work reports about the development of a new state estimation method, specific for radial distribution systems. The main algorithm of the method is based on the power summation load flow. The estimation is carried out piecewise, section by section of the feeder, going from the substation to the terminal nodes. For each section, a measurement model is built, resulting in a nonlinear overdetermined equations set, whose solution is achieved by the Gaussian normal equation. The estimated variables of a section are used as pseudo-measurements for the next section. In general, a measurement set for a generic section consists of pseudo-measurements of power flows and nodal voltages obtained from the previous section or measurements in real-time, if they exist -, besides pseudomeasurements of injected powers for the power summations, whose functions are the load flow equations, assuming that the network can be represented by its single-phase equivalent. The great advantage of the algorithm is its simplicity and low computational effort. Moreover, the algorithm is very efficient, in regard to the accuracy of the estimated values. Besides the power summation state estimator, this work shows how other algorithms could be adapted to provide state estimation of middle voltage substations and networks, namely Schweppes method and an algorithm based on current proportionality, that is usually adopted for network planning tasks. Both estimators were implemented not only as alternatives for the proposed method, but also looking for getting results that give support for its validation. Once in most cases no power measurement is performed at beginning of the feeder and this is required for implementing the power summation estimations method, a new algorithm for estimating the network variables at the middle voltage bus-bar was also developed

Desenvolvimento de material compósito a base de raspa de pneu e látex para isolamento térmico

The process of recycling has been stimulated by the markets for several reasons, mainly on economical and environmental. Several products have been developed from recycled materials that already exist as well as several residues have been studied in different forms of applications. The greater majority of the applications for thermal insulation in the domestic, commercial and industrial systems have been elaborated in the temperature ranges between low to medium reaching up to 180oC. Many materials such as glass wool, rock wool, polystyrene are being used which are aggressive to the environment. Such materials in spite of the effectiveness in the retention of heat flow, they cost more and when discarded take several years to be absorbed by the nature. This way, in order to adapt to a world politics concerning the preservation of the environment, the present study was intended to develop a material composed of natural/biodegradable materials and industrial residues. The development of such a product in the form of a composite material based on tyre scrapes and latex for thermal insulation is presented in this research work. Thermal and physical properties of the tire scrapes as well as latex were studied in order to use them as raw materials for the manufacture of the intended composite to be applied as a thermal insulator in hot and cold systems varying between 0ºC and 200oC, respectively. Composite blankets were manufactured manually, in weight proportions of 1:1 (50:50%); 1:2 (33:67%) and 2:1 (67:33%) (tire scrapes: latex) respectively. Physical, mechanical and thermal properties of the composites were analyzed to obtain data about the viability of using the composite as a thermal insulator. The analyses carried out were based on standards ABNT, ASTM and UL. The maximum temperature obtained for the composite as a thermal insulator was 200ºC, which meets the range of applications that could be used as a thermal insulator in domestic as well as industrial purposes. The experimental results prove that the composite can be used as a thermal insulator on heated or cooled surface

Avaliação e modelagem reológica de fluido de perfuração base água

The determination of the rheology of drilling fluids is of fundamental importance to select the best composition and the best treatment to be applied in these fluids. This work presents a study of the rheological behavior of some addictives used as viscosifiers in water-based drilling fluids. The evaluated addictives were: Carboxymethylcellulose (CMC), Xanthan gum (GX), and Bentonite. The main objective was to rheologically characterize suspensions composed by these addictives, by applying mathematical models for fluid flow behavior, in order to determine the best flow equation to represent the system, as well as the model parameters. The mathematical models applied in this research were: the Bingham Model, the Ostwald de Wale Model, and the Herschel-Bulkley Model. A previous study of hydration time for each used addictive was accomplished seeking to evaluate the effect of polymer and clay hydration on rheological behavior of the fluid. The rheological characterization was made through typical rheology experiments, using a coaxial cylinder viscosimeter, where the flow curves and the thixotropic magnitude of each fluid was obtained. For each used addictive the rheological behavior as a function of temperature was also evaluated as well as fluid stability as a function of the concentration and kind of addictive used. After analyses of results, mixtures of polymer and clay were made seeking to evaluate the rheological modifications provided by the polymer incorporation in the water + bentonite system. The obtained results showed that the Ostwald de Waale model provided the best fit for fluids prepared using CMC and for fluids with Xanthan gum and Bentonite the best fit was given by the Herschel-Bulkley one

Artificial neural networks for load flow and external equivalents studies

In this paper an artificial neural network (ANN) based methodology is proposed for (a) solving the basic load flow, (b) solving the load flow considering the reactive power limits of generation (PV) buses, (c) determining a good quality load flow starting point for ill-conditioned systems, and (d) computing static external equivalent circuits. An analysis of the input data required as well as the ANN architecture is presented. A multilayer perceptron trained with the Levenberg-Marquardt second order method is used. The proposed methodology was tested with the IEEE 30- and 57-bus, and an ill-conditioned 11-bus system. Normal operating conditions (base case) and several contingency situations including different load and generation scenarios have been considered. Simulation results show the excellent performance of the ANN for solving problems (a)-(d). (C) 2010 Elsevier B.V. All rights reserved.

Geração de processos WS-BPEL com base em um algoritmo de reescrita de regras

Web services are computational solutions designed according to the principles of Service Oriented Computing. Web services can be built upon pre-existing services available on the Internet by using composition languages. We propose a method to generate WS-BPEL processes from abstract specifications provided with high-level control-flow information. The proposed method allows the composition designer to concentrate on high-level specifi- cations, in order to increase productivity and generate specifications that are independent of specific web services. We consider service orchestrations, that is compositions where a central process coordinates all the operations of the application. The process of generating compositions is based on a rule rewriting algorithm, which has been extended to support basic control-flow information.We created a prototype of the extended refinement method and performed experiments over simple case studies

Substâncias húmicas: sistema de fracionamento sequencial por ultrafiltração com base no tamanho molecular

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

A pH optode based on thymol blue: application to determination of CO2 using flow injection analysis system

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Simultaneous effects of total solids content, milk base, heat treatment temperature and sample temperature on the rheological properties of plain stirred yogurt

Response surface methodology was used to establish a relationship between total solids content, milk base, heat treatment temperature, and sample temperature, and consistency index, flow behaviour index, and apparent viscosity of plain stirred yogurts. Statistical treatments resulted in developments of mathematical models. All samples presented shear thinning fluid behaviour. The increase of the content of total solids (9.3-22.7 %) and milk base heat treatment temperature (81.6-98.4°C) resulted in a significant increase in consistency index and a decrease in flow behaviour index. Increase in the sample temperature (1.6-18.4°C) caused a decrease in consistency index and increase in flow behaviour index. Apparent viscosity was directly related to the content of total solids. Rheological properties of yogurt were highly dependent on the content of total solids in milk.

Classificação de práticas de gestão de fluxo em cadeias de suprimentos: uma visão com base em sistemas puxados e empurrados

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)