Investigação de aquífero fraturado para entendimento de fluxo e transporte de contaminantes clorados: estudo de caso em Valinhos, SP

Casos de contaminação de aquíferos fraturados são bastante complexos, tendo em vista a heterogeneidade das redes de fraturas, e no geral, sua investigação demanda a utilização de técnicas pouco usuais, como por exemplo o imageamento acústico e a perfilagem de velocidade de fluxo de água. Na área de estudo, localizada em Valinhos/SP, o uso inadequado de solventes organoclorados no passado ocasionou a contaminação do aquífero raso em duas áreas, e o aparecimento de concentrações no aquifero profundo levaram a condução do atual trabalho, que teve como principal objetivo a elaboração de um modelo conceitual de fluxo de água e transporte de contaminantes no aquífero cristalino. Previamente à investigação do aquífero fraturado, foi realizada uma análise de trabalhos existentes, incluindo a interpretação de lineamentos, levantamentos geológicos além de perfilagens geofísicas de superfície. Em cada área investigada, foi realizada a perfuração de um poço profundo e aplicadas as técnicas de perfilagens de raios gama, cáliper, flowmeter, imageamento acústico, além da filmagem do poço e realização de ensaios hidráulicos nos dois pontos perfurados. Para caracterização química do aquífero fraturado, foram realizadas coletas de água subterrânea em intervalos selecionados com a utilização de obturadores pneumáticos. As cargas hidráulicas medidas durante a amostragem também auxiliaram no entendimento da direção do fluxo de água. O aquífero cristalino é formado por rochas gnáissicas e se encontra bastante fraturado e intemperizado, principalmente na porção superficial da rocha (até aproximadamente 65,0 m) onde as maiores velocidades de fluxo de água também foram observadas. A rocha sã possui uma menor densidade de fraturas e predominância de minerais mais claros. As fraturas de baixo a médio angulo de mergulho (Grupo 1) são as mais frequentes em ambas as perfurações e possuem direção principal N-S a NE-SW. São observadas, no geral, exercendo grande influência sobre o fluxo de água, principalmente na porção alterada do gnaisse. Fraturas com ângulo elevado de mergulho, classificadas como Grupo 2 (paralelas à foliação) e Grupo 3 (direção NW à W), são também observadas ao longo de toda a perfuração estabelecendo a conexão hidráulica entre as fraturas do Grupo 1. Em menor proporção, são ainda verificadas fraturas com ângulos de mergulho >40 ° pertencente aos Grupos 4 (NE-SW), 5 (E-W), 6 (NW-SE) e 7 (E-W). O fluxo de água subterrânea se mostrou descendente na porção superior da rocha alterada e ascendente na porção mais profunda, possivelmente direcionando a água subterrânea para a região de transição da rocha mais alterada para a rocha sã (entre 61 a 65 m de profundidade). Apesar do fluxo ascendente em profundidade, o bombeamento de poços tubulares existentes no entorno ao longo dos anos, favoreceu a migração dos contaminantes para porções mais profundas. Os contaminantes observados no poço tubular P6 possuem maior semelhança com os contaminantes observados na Área 2, e ambos estão localizados entre lineamentos NW-SE, indicando uma possível influência dos lineamentos no controle sobre o fluxo de água. No entanto, para entendimento do transporte dos contaminantes em área, é necessário um adensamento da rede de monitoramento, levando em consideração a heterogeneidade do meio e as incertezas relacionadas à extrapolação dos dados para áreas não investigadas.

Análise do padrão IEEE 802.11g para a comunicação do sistema de controle distribuído de semáforos.

Este trabalho propõe a análise da comunicação sem fio para um sistema de controle distribuído de semáforos, a partir da revisão das literaturas, realização de simulações e experimentos, os quais consideram as especificações estabelecidas para o sistema de semáforos. As simulações e os experimentos se baseiam na avaliação do comportamento da comunicação perante a alteração de alguns parâmetros de configuração da rede. O estudo apresentado envolve análises relacionadas ao padrão IEEE 802.11g e às definições da camada física apresentadas nas especificações do padrão. Os métodos utilizados envolvem o estudo e experimentação de parâmetros relacionados à potência de transmissão e recepção, além de análise dos esquemas de modulação utilizados pelo padrão IEEE 802.11g. A metodologia aplicada a este trabalho envolve o conhecimento das características e capacidade dos esquemas de modulação responsáveis pela definição das taxas de transmissão. As análises mostram que a possibilidade de adequação dos parâmetros de configuração de rede, levando em consideração o cenário de aplicação, pode ser um fator essencial para o bom desempenho de todo o sistema.

O EFEITO DO CONTROLE RESPIRATÓRIO EM VARIÁVEIS ELETROFISIOLÓGICAS DA ATENÇÃO

A prática do ioga tem se tornado cada vez mais popular, não apenas pelos benefícios físicos, mas principalmente pelo bem-estar psicológico trazido pela sua prática. Um dos componentes do ioga é o Prãnãyama, ou controle da respiração. A atenção e a respiração são dois mecanismos fisiológicos e involuntários requeridos para a execução do Prãnãyama. O principal objetivo desse estudo foi verificar se variáveis contínuas do EEG (potência de diferentes faixas que o compõem) seriam moduladas pelo controle respiratório, comparando-se separadamente as duas fases do ciclo respiratório (inspiração e expiração), na situação de respiração espontânea e controlada. Fizeram parte do estudo 19 sujeitos (7 homens/12 mulheres, idade média de 36,89 e DP = ± 14,46) que foram convidados a participar da pesquisa nas dependências da Faculdade de Saúde da Universidade Metodista de São Paulo. Para o registro do eletroencefalograma foi utilizado um sistema de posicionamento de cinco eletrodos Ag AgCl (FPz, Fz, Cz, Pz e Oz) fixados a uma touca de posicionamento rápido (Quick-Cap, Neuromedical Supplies®), em sistema 10-20. Foram obtidos valores de máxima amplitude de potência (espectro de potência no domínio da frequência) nas frequências teta, alfa e beta e delta e calculada a razão teta/beta nas diferentes fases do ciclo respiratório (inspiração e expiração), separadamente, nas condições de respiração espontânea e de controle respiratório. Para o registro do ciclo respiratório, foi utilizada uma cinta de esforço respiratório M01 (Pletismógrafo). Os resultados mostram diferenças significativas entre as condições de respiração espontânea e de controle com valores das médias da razão teta/beta menores na respiração controlada do que na respiração espontânea e valores de média da potência alfa sempre maiores no controle respiratório. Diferenças significativas foram encontradas na comparação entre inspiração e expiração da respiração controlada com diminuição dos valores das médias da razão teta/beta na inspiração e aumento nos valores das médias da potência alfa, sobretudo na expiração. Os achados deste estudo trazem evidências de que o controle respiratório modula variáveis eletrofisiológicas relativas à atenção refletindo um estado de alerta, porém mais relaxado do que na situação de respiração espontânea.

Fluxo de fluído através de um meio poroso fractal desordenado. Análise das tensões de cisalhamento e efeito de escala na estimativa das forças viscosas

In this work we have investigated some aspects of the two-dimensional flow of a viscous Newtonian fluid through a disordered porous medium modeled by a random fractal system similar to the Sierpinski carpet. This fractal is formed by obstacles of various sizes, whose distribution function follows a power law. They are randomly disposed in a rectangular channel. The velocity field and other details of fluid dynamics are obtained by solving numerically of the Navier-Stokes and continuity equations at the pore level, where occurs actually the flow of fluids in porous media. The results of numerical simulations allowed us to analyze the distribution of shear stresses developed in the solid-fluid interfaces, and find algebraic relations between the viscous forces or of friction with the geometric parameters of the model, including its fractal dimension. Based on the numerical results, we proposed scaling relations involving the relevant parameters of the phenomenon, allowing quantifying the fractions of these forces with respect to size classes of obstacles. Finally, it was also possible to make inferences about the fluctuations in the form of the distribution of viscous stresses developed on the surface of obstacles.

Avaliação do controle da diagênese na qualidade de reservatório siliciclástico do cenomaniano superior da formação Açu, sudoeste da bacia potiguar

The distribution of diagenetic alterations in Late Cenomanian siliciclastic reservoirs from Potiguar Basin was influenced by the stratigraphic framework and the depositional system. Seismic sections and geophysical logs of two wells drilled in the SW portion of the mentioned basin above register regional stratigraphic surfaces representing maximum floods related to a transgressive event. The sequential analysis of 80 m of drill core (~450 m deep) recognized nine depositional facies with an upwards granodecrescent standard piling that limits cycles with an erosional conglomeratic base (lag) overlain by intercalations of medium to very fine sandstones showing cross bedding (channel, planar and low angled) and horizontal bedding (plane-parallel , wave and flaser). The top of the cycles is marked by the deposition of pelites and the development of paleosoils and lagoons. The correlation of genetically related facies reveals associations of channel fillings, crevasse, and flood plains deposited in a transgressive system. Detailed descriptions of seventy nine thin sections aided by MEV-EBSD/EDS, DRX and stable isotope analyses in sandstones revealed an arcosian composition and complex textural arrays with abundant smectite fringes continuously covering primary components, mechanically infiltrated cuticles and moldic and intragrain pores. K-feldspar epitaxial overgrowth covers microcline and orthoclase grains before any other phase. Abundant pseudomatrix due to the compactation of mud intraclasts concentrate along the stratification planes, locally replaced by macrocristalline calcite and microcrystalline and framboidal pyrite. Kaolinite (booklets and vermicular), microcrystalline smectite, microcrystalline titanium minerals and pyrite replace the primary components. The intergrain porosity prevails over the moldic, intragrain and contraction porosities. The pores are poorly connected due to the presence of intergranular smectite, k-feldspar overgrowth, infiltrated mud and pseudomatrix. The sandstones were subjected to eodiagenetic conditions next to the surface and shallow burial mesodiagenetic conditions. The diagenetic alterations reduced the porosity and the permeability mainly due to the precipitation of smectite fringes, compactation of mud intraclasts onto the pseudomatrix and cementing by poikilotopic calcite characterizing different reservoir petrofacies. These diagenetic products acted as barriers and detours to the flow of fluids thus reducing the quality of the reservoir.

Regulador eletromagnético de frequência aplicado no controle de velocidade de geradores eólicos

The constant necessity for new sources of renewable energy is increasingly promoting the increase of investments in this area. Among other sources, the wind power has been becoming prominent. It is important to promote the search for the improvement of the technologies involved in the topologies of the wind turbines, seeking for alternatives which enhance the gotten performance, despite the irregularity of the wind speed. This study presents a new system for speed control, in this case applied to the wind turbines - the Electromagnetic Frequency Regulator (EFR). One of the most used devices in some topologies is the mechanical gearboxes which, along with a short service life, often represent sources of noise and defects. The EFR does not need these transmission boxes, representing a technological advancement, using for that an adapted induction machine, in which the stator becomes mobile, supportive to the axis of the turbine. In the topology used in this study, the EFR also allows us to leave out the usage of the eletronic converters to establish the coupling between the generator and the electrical grid. It also the reason why it provides the possibility of obtaining the generation in alternating current, with constant voltage and frequency, where there is no electrical grid. Responsable for the mechanical speed control of the generator, the EFR can be useful in other transmission systems in which the mechanical speed control output is the objective. In addition, the EFR operates through the combination of two inputs, a mechanical and other electrical. It multiplies the possibilities of application because it is able to synergistic coupling between different arrays of energy, and, for such reasons, it enables the various sources of energy involved to be uncoupled from the network, being the synchronous generator responsible for the system connection with the electrical grid, simplifying the control strategies on the power injected in it. Experimental and simulation results are presented through this study, about a wind turbine, validating the proposal related to the efficience in the speed control of the system for different wind conditions.

Topologia de gerador de distúrbios elétricos baseada em conversores de potência

Electrical disturbances such as voltage sags, interruptions and voltage unbalances might cause serious problems for the end-user and for the companies of generation and transmission of energy. Few years ago, those companies have been using methods and equipments of protection to avoid the disturbances’ presence or to mitigate their effects on the power system. Disturbances generators are used to analyse the behavior of electrical and electronic equipments affected by disturbances. The analysis of those failures allows the development of appropriated protection equipments. In this paper, the development of a disturbances generator based on power converters is presented. The disturbance generator developed is able to generate some symmetrical disturbances, such as: voltage sags, voltage swells and harmonic distortion. The control strategy used in the disturbance generator is based on discrete and repetitive control. The steps of the design of the control and of the filter used for reducing harmonic in the output, are detailed in the text. Are presented the obtained results on computational simulations and the obtained results on laboratory tests.

Contribuições para estratégia de controle aplicada à geração fotovoltaica interconectada à rede elétrica

Generation systems, using renewable sources, are becoming increasingly popular due to the need for increased use of electricity. Currently, renewables sources have a role to cooperate with conventional generation, due to the system limitation in delivering the required power, the need for reduction of unwanted effects from sources that use fossil fuels (pollution) and the difficulty of building new transmission and/or distribution lines. This cooperation takes place through distributed generation. Therefore, this work proposes a control strategy for the interconnection of a PV (Photovoltaic) system generation distributed with a three-phase power grid through a connection filter the type LCL. The compensation of power quality at point of common coupling (PCC) is performed ensuring that the mains supply or consume only active power and that his currents have low distorcion. Unlike traditional techniques which require schemes for harmonic detection, the technique performs the harmonic compensation without the use of this schemes, controlling the output currents of the system in an indirect way. So that there is effective control of the DC (Direct Current) bus voltage is used the robust controller mode dual DSMPI (Dual-Sliding Mode-Proportional Integral), that behaves as a sliding mode controller SM-PI (Sliding Mode-Proportional Integral) during the transition and like a conventional PI (Proportional Integral) in the steady-state. For control of current is used to repetitive control strategy, which are used double sequence controllers (DSC) tuned to the fundamental component, the fifth and seventh harmonic. The output phase current are aligned with the phase angle of the utility voltage vector obtained from the use of a SRF-PLL (Synchronous Reference Frame Phase-Locked-Loop). In order to obtain the maximum power from the PV array is used a MPPT (Maximum Power Point Tracking) algorithm without the need for adding sensors. Experimental results are presented to demonstrate the effectiveness of the proposed control system.

Mapeamento, interações e gerenciamento do fluxo de pacientes da Maternidade Escola Januário Cicco - MEJC

The process mapping is an important tool in the management of organizations, allowing better levels of productivity, quality and reciprocity concerning the implementation and decision-making. It benefits in a clear way the process organization and assures the manager a macro vision of the system. In this sense, the objective of this study is to describe the mapping process as it occurs in the Januario Cicco Maternity School–MEJC. The bibliographic and descriptive research included interviews, observations and researches in many databases. The study analyzed the limiting points of the detected flow trying to find a better comprehension of the flow of patients in the maternity in order to offer the gestors the information necessary to improve the quality of the assistance as well as a general view of the flow of patients and any change detected there. As a result, we believe that the process mapping may become a relevant factor to the organizational management of MEJC, in view that it is an element that can contribute to ease up the management of information studied, considering that the perfect change of information inside a complex system will produce improvements in all spheres of this institution.

Desenvolvimento e validação de testes de fluxo lateral para a detecção de cultivares geneticamente modificados e de aflatoxinas em produtos agrícolas

The expansion of cultivated areas with genetically modified crops (GM) is a worldwide phenomenon, stimulating regulatory authorities to implement strict procedures to monitor and verify the presence of GM varieties in agricultural crops. With the constant growing of plant cultivating areas all over the world, consumption of aflatoxin-contaminated food also increased. Aflatoxins correspond to a class of highly toxic contaminants found in agricultural products that can have harmful effects on human and animal health. Therefore, the safety and quality evaluation of agricultural products are important issues for consumers. Lateral flow tests (strip tests) is a promising method for the detection both proteins expressed in GM crops and aflatoxins-contaminated food samples. The advantages of this technique include its simplicity, rapidity and cost-effective when compared to the conventional methods. In this study, two novel and sensitive strip tests assay were developed for the identification of: (i) Cry1Ac and Cry8Ka5 proteins expressed in GM cotton crops and; (ii) aflatoxins from agricultural products. The first strip test was developed using a sandwhich format, while the second one was developed using a competitive format. Gold colloidal nanoparticles were used as detector reagent when coated with monoclonal antibodies. An anti-species specific antibody was sprayed at the nitrocellulose membrane to be used as a control line. To validate the first strip test, GM (Bollgard I® e Planta 50- EMBRAPA) and non-GM cotton leaf (Cooker 312) were used. The results showed that the strip containing antibodies for the identification of Cry1Ac and Cry8Ka5 proteins was capable of correctly distinguishing between GM samples (positive result) and non-GM samples (negative result), in a high sensitivity manner. To validate the second strip test, artificially contaminated soybean with Aspergillus flavus (aflatoxin-producing fungus) was employed. Food samples, such as milk and soybean, were also evaluated for the presence of aflatoxins. The strip test was capable to distinguish between samples with and without aflatoxins samples, at a sensitivity concentration of 0,5 μg/Kg. Therefore, these results suggest that the strip tests developed in this study can be a potential tool as a rapid and cost-effective method for detection of insect resistant GM crops expressing Cry1Ac and Cry8Ka5 and aflatoxins from food samples.

Desenvolvimento e validação de testes de fluxo lateral para a detecção de cultivares geneticamente modificados e de aflatoxinas em produtos agrícolas

The expansion of cultivated areas with genetically modified crops (GM) is a worldwide phenomenon, stimulating regulatory authorities to implement strict procedures to monitor and verify the presence of GM varieties in agricultural crops. With the constant growing of plant cultivating areas all over the world, consumption of aflatoxin-contaminated food also increased. Aflatoxins correspond to a class of highly toxic contaminants found in agricultural products that can have harmful effects on human and animal health. Therefore, the safety and quality evaluation of agricultural products are important issues for consumers. Lateral flow tests (strip tests) is a promising method for the detection both proteins expressed in GM crops and aflatoxins-contaminated food samples. The advantages of this technique include its simplicity, rapidity and cost-effective when compared to the conventional methods. In this study, two novel and sensitive strip tests assay were developed for the identification of: (i) Cry1Ac and Cry8Ka5 proteins expressed in GM cotton crops and; (ii) aflatoxins from agricultural products. The first strip test was developed using a sandwhich format, while the second one was developed using a competitive format. Gold colloidal nanoparticles were used as detector reagent when coated with monoclonal antibodies. An anti-species specific antibody was sprayed at the nitrocellulose membrane to be used as a control line. To validate the first strip test, GM (Bollgard I® e Planta 50- EMBRAPA) and non-GM cotton leaf (Cooker 312) were used. The results showed that the strip containing antibodies for the identification of Cry1Ac and Cry8Ka5 proteins was capable of correctly distinguishing between GM samples (positive result) and non-GM samples (negative result), in a high sensitivity manner. To validate the second strip test, artificially contaminated soybean with Aspergillus flavus (aflatoxin-producing fungus) was employed. Food samples, such as milk and soybean, were also evaluated for the presence of aflatoxins. The strip test was capable to distinguish between samples with and without aflatoxins samples, at a sensitivity concentration of 0,5 μg/Kg. Therefore, these results suggest that the strip tests developed in this study can be a potential tool as a rapid and cost-effective method for detection of insect resistant GM crops expressing Cry1Ac and Cry8Ka5 and aflatoxins from food samples.

Estudo comparativo de dois conversores Boost quadrático com comutação suave monochaveados para aplicação de rastreamento de máxima potência em sistemas fotovoltaicos

This paper makes a comparative study of two Soft Single Switched Quadratic Boost Converters (SSS1 and SSS2) focused on Maximum Power Point Tracking (MPPT) of a PV array using Perturb and Observe (P&O) algorithm. The proposed converters maintain the static gain characteristics and dynamics of the original converter with the advantage of considerably reducing the switching losses and Electromagnetic Interference (EMI). It is displayed the input voltage Quadratic Boost converter modeling; qualitative and quantitative analysis of soft switching converters, defining the operation principles, main waveforms, time intervals and the state variables in each operation steps, phase planes of resonant elements, static voltage gain expressions, analysis of voltage and current efforts in semiconductors and the operational curves at 200 W to 800 W. There are presented project of PI, PID and PID + Notch compensators for MPPT closed-loop system and resonant elements design. In order to analyze the operation of a complete photovoltaic system connected to the grid, it was chosen to simulate a three-phase inverter using the P-Q control theory of three-phase instantaneous power. Finally, the simulation results and experimental with the necessary comparative analysis of the proposed converters will be presented.

Controladores repetitivos aplicados a filtros ativos de potência sob variações de carga e de frequência da rede

This work presents the development and modification of techniques to reduce the effects of load variation and mains frequency deviation in repetitive controllers applied to active power filters. To minimize the effects of aperiodic signals resulting from the connection or disconnection of non-linear loads is developed a technique which recognizes linear and nonlinear loads, and operates to reset the controller only when the error due to the transition of considerable value, and the transition is from non-linear to linear load. An algorithm to adapt the gain of the repetitive controller, based on a sigmoid function adaptation, in order to minimize the effects caused by random noise in the measurement system is also used. This work also analyzes the effects of frequency variation and presents the main methods to cope with this situation. Some solutions are the change in the number of samples per period and the variation of the sampling rate. The first has the advantage of using linear design techniques and results in a time invariant system. The second method changes the sampling frequency and leads to a time variant system that demands a difficult analysis of stability. The proposed algorithms were tested using the methods of truncation of the number of samples and the method of changing the sampling rate of the system to compensate possible frequency variations of the grid. Experimental results are presented to validate the proposal.

Controle de uma microrrede ilhada baseada em geração eólica-diesel com alto nível de inserção de geração eólica

The insertion of distributed generation units in the electric power systems have contributed to the popularization of microgrid concepts. With the microgrids, several potential benefits can be achieved in regard to power quality and supply reliability. However, several technical challenges related to the control and operation of microgrids, which are associated with high insertion of generation systems based on static converters, must be overcame. Among the opportunities in the context of microgrids, there is the islanded operation of microgrids temporarily disconnected from the electric power systems and also the autonomous operation of geographically isolated microgrids. The frequency in large power systems is traditionally controlled by the generation units based on traditional synchronous generator. The insertion of distributed generation units based on static power converters may bring difficulties to the frequency control in microgrids, due to the reduction of the equivalent inertia of conventional synchronous generators present in islanded and isolated microgrids. In this context, it becomes necessary the proposition of new operational and control strategies for microgrids control, taking into account the presence of distributed generation units based on full-rated converter. This paper proposes an operational and control strategy for the islanded operation of a winddiesel microgrid with high insertion level of wind generation. The microgrid adopted in this study comprises of a wind energy conversion system with synchronous generator based on full rated converter, a diesel generator (DIG) and a dump load. Due to the high insertion level of wind generation, the wind unit operates in Vf mode and the diesel generator operates in PQ mode. The diesel generator and the dump load are used to regulate the DC-link voltage of the wind generation unit. The proposed control allows the islanded operation of the microgrid only with wind generation, wind-only mode (WO), and with wind-diesel generation, wind-diesel mode (WD). For the wind-only mode, with 100% of penetration level of wind generation, it is proposed a DC-link voltage control loop based on the use of a DC dump load. For the winddiesel mode, it is proposed a DC-link voltage control loop added to the diesel generator, which is connected to the AC side of the microgrid, in coordinated action with the dump load. The proposed operational and control strategy does not require the use of batteries and aims to maximize the energy production from wind generation, ensuring the uninterrupted operation of the microgrid. The results have showed that the operational and control strategy allowed the stable operation of the islanded microgrid and that the DC-link voltage control loop added to the diesel generator and the dump load proved to be effective during the typical variations of wind speed and load.

Arquitetura híbrida com DSP e FPGA para implementação de controladores de filtros ativos de potência

The presence of non-linear loads at a point in the distribution system may deform voltage waveform due to the consumption of non-sinusoidal currents. The use of active power filters allows significant reduction of the harmonic content in the supply current. However, the processing of digital control structures for these filters may require high performance hardware, particularly for reference currents calculation. This work describes the development of hardware structures with high processing capability for application in active power filters. In this sense, it considers an architecture that allows parallel processing using programmable logic devices. The developed structure uses a hybrid model using a DSP and an FPGA. The DSP is used for the acquisition of current and voltage signals, calculation of fundamental current related controllers and PWM generation. The FPGA is used for intensive signal processing, such as the harmonic compensators. In this way, from the experimental analysis, significant reductions of the processing time are achieved when compared to traditional approaches using only DSP. The experimental results validate the designed structure and these results are compared with other ones from architectures reported in the literature.