Obtenção de filtro cerâmico a partir da diatomita e casca de arroz carbonizada visando tratamento de efluente têxtil

The effluents released by the textile industry have high concentrations of alkali, carbohydrates, proteins, in addition to colors containing heavy metals. Therefore, a filter was prepared aiming primarily to the removal of color. In order to prepare this filter, rice hulls and diatomite were used, which have in their structure, basically amorphous hydrated silica. The silica exists in three crystalline forms: quartz, tridymite and cristobalite. In accordance with the above considerations, this study was divided into two stages; the first corresponds to the preparation of the filter and the second to carry out the tests in the effluent/filter in order to verify the efficiency of the color removal. First, the raw material was subjected to a chemical analysis and XRD, and then the diatomite was mixed, via humid, with a planetarium windmill with 20 %, 40 %, 60 % and 80 % of rice husk ash. To the mixture, 5 % carboxymethylcellulose (CMC) was added as a binder at room temperature. The samples were uniaxially compacted into metallic matrix of 0.3 x 0.1 cm² of area at a pressure of 167 MPa by means of hydraulic press and then sintered at temperatures of 1,000 °C, 1,200 °C and 1,400 °C for 1 h and submitted to granulometry test using laser, linear retraction, water absorption, apparent porosity and resistance to bending, DTA, TMA and XRD. To examine the pore structure of the samples scanning electron microscope (SEM) was used. Also tests were carried out in a mercury porosimeter to verify the average size of the pores and real density of the samples. In the second stage, samples of the effluent were collected from a local industry, whose name will be preserved, located in Igapó, in the State of Rio Grande do Norte - RN. The effluent was first pretreated before filtration and then subjected to a treatment of flotation. The effluent was then characterized before and after filtration, with parameters of color, turbidity, suspended solids, pH, chemical and biochemical oxygen demand (COD and BOD). Thus, through the XRD analysis the formation of cristobalite α in all samples was observed. The best average size of pore was found to be 1.75 μm with 61.04 % apparent porosity, thus obtaining an average 97.9 % color removal and 99.8 % removal of suspended solid

Filtro kl/dvs para atenuação do ruído "ground roll"

In geophysics there are several steps in the study of the Earth, one of them is the processing of seismic records. These records are obtained through observations made on the earth surface and are useful for information about the structure and composition of the inaccessible parts in great depths. Most of the tools and techniques developed for such studies has been applied in academic projects. The big problem is that the seismic processing power unwanted, recorded by receivers that do not bring any kind of information related to the reflectors can mask the information and/or generate erroneous information from the subsurface. This energy is known as unwanted seismic noise. To reduce the noise and improve a signal indicating a reflection, without losing desirable signals is sometimes a problem of difficult solution. The project aims to get rid of the ground roll noise, which shows a pattern characterized by low frequency, low rate of decay, low velocity and high amplituds. The Karhunen-Loève Transform is a great tool for identification of patterns based on the eigenvalues and eigenvectors. Together with the Karhunen-Loève Transform we will be using the Singular Value Decomposition, since it is a great mathematical technique for manipulating data

Avaliação ecológico-econômica do manguezal de Macau/RN e a importância da aplicação de práticas preservacionistas pela indústria petrolífera local

This work presents the results of a survey in oil-producing region of the Macau City, northern coast of Rio Grande do Norte. All work was performed under the Project for Monitoring Environmental Change and the Influence of Hydrodynamic forcing on Morphology Beach Grass Fields, Serra Potiguar in Macau, with the support of the Laboratory of Geoprocessing, linked to PRH22 - Training Program in Geology Geophysics and Information Technology Oil and Gas - Department of Geology/CCET/UFRN and the Post-Graduation in Science and Engineering Oil/PPGCEP/UFRN. Within the economic-ecological context, this paper assesses the importance of mangrove ecosystem in the region of Macau and its surroundings as well as in the following investigative exploration of potential areas for projects involving reforestation and / or Environmental Restoration. At first it was confirmed the ecological potential of mangrove forests, with primary functions: (i) protection and stabilization of the shoreline, (ii) nursery of marine life, and (iii) source of organic matter to aquatic ecosystems, (iv) refuge of species, among others. In the second phase, using Landsat imagery and techniques of Digital Image Processing (DIP), I came across about 18,000 acres of land that can be worked on environmental projects, being inserted in the rules signed the Kyoto Protocol to the market carbon. The results also revealed a total area of 14,723.75 hectares of activity of shrimp production and salting that can be harnessed for the social, economic and environmental potential of the region, considering that over 60% of this area, ie, 8,800 acres, may be used in the planting of the genus Avicennia considered by the literature that the species best sequesters atmospheric carbon, reaching a mean value of 59.79 tons / ha of mangrove

Padrões de coexistência e utilização do hábitat por duas espécies de Herpsilochmus (Aves: Thamnophilidae)

How ecologically similar species are able to coexist has always generated great interest in the scientific community. Classical niche theory predicts that species coexistence is only possible when they segregate in at least one dimension of the ecological niche, thus leading to ecological differentiation among species. However, recent work has shown that species that are more similar in some ecological traits are the ones more prone to be able to coexist (environmental filter). The knowledge of how these forces act shaping ecological communities can reveal co-existence strategies, providing important information for management and conservation of the species. This study tested these hypotheses using a pair of coexisting species of Herpsilochmus, H. pectoralis and H. sellowi. In this study I use high resolution (50 x 50 m) ecological niche models to Identify which environmental factors best predict species occurrence. Next, I calculate the overlap in habitat use by species and build null models to test the hypothesis of spatial niche segregation. In addition, I obtain the selectivity parameters of habitat use to test whether the species H. pectoralis (larger body size) is less selective than H. sellowi (smaller body size) as stated in the literature for other species. The results reject the ecological equivalence among species, revealing that the species of Herpsilochmus explore the habitat differently, having different environmental niches. The hypothesis of environmental filter was not observed in my analysis, the observed overlap in habitat use among species was lower than expected by chance. Evidence that Herpsilochmus are spatially segregating reinforces the hypothesis of interspecific competition as the predominant force in the selection of microhabitat of the species. However, more data and experiments are necessary to state categorically that the observed pattern is a result of current or past competition

Implementação experimental de filtro ativo paralelo de potência com aplicação a gerador de indução trifásico

This work describes the experimental implementation of a shunt active power filter applied to a three-phase induction generator. The control strategy of active filter turned to the excitation control of the machine and to decrease the harmonics in the generator output current. Involved the implementation of a digital PWM switching, and was made a comparison of two techniques for obtaining the reference currents. The first technique is based on the synchronous dq reference method and the second on the theory of instantaneous power. The comparison is performed via simulation and experimental results. To obtain the experimental results, was mounted a bench trial and the control and communications needed were implemented using DSP - MS320F2812. The simulation results and experimental data proved the efficiency of the filter to apply, highlighting the technique of instantaneous power

Estratégia de controle robusto para filtro ativo paralelo sem detecção de harmônicos de correntes

Conventional control strategies used in shunt active power filters (SAPF) employs real-time instantaneous harmonic detection schemes which is usually implements with digital filters. This increase the number of current sensors on the filter structure which results in high costs. Furthermore, these detection schemes introduce time delays which can deteriorate the harmonic compensation performance. Differently from the conventional control schemes, this paper proposes a non-standard control strategy which indirectly regulates the phase currents of the power mains. The reference currents of system are generated by the dc-link voltage controller and is based on the active power balance of SAPF system. The reference currents are aligned to the phase angle of the power mains voltage vector which is obtained by using a dq phase locked loop (PLL) system. The current control strategy is implemented by an adaptive pole placement control strategy integrated to a variable structure control scheme (VS¡APPC). In the VS¡APPC, the internal model principle (IMP) of reference currents is used for achieving the zero steady state tracking error of the power system currents. This forces the phase current of the system mains to be sinusoidal with low harmonics content. Moreover, the current controllers are implemented on the stationary reference frame to avoid transformations to the mains voltage vector reference coordinates. This proposed current control strategy enhance the performance of SAPF with fast transient response and robustness to parametric uncertainties. Experimental results are showing for determining the effectiveness of SAPF proposed control system

Estudos e projetos de filtro interdigital em microfita para aplicação prática ao transponder do satélite ITASAT

This work shows a theoretical analysis together with numerical and experimental results of transmission characteristics from the microstrip bandpass filters with different geometries. These filters are built over isotropic dielectric substrates. The numerical analysis is made by specifical commercial softwares, like Ansoft Designer and Agilent Advanced Design System (ADS). In addition to these tools, a Matlab Script was built to analyze the filters through the Finite-Difference Time-Domain (FDTD) method. The filters project focused the development of the first stage of filtering in the ITASAT s Transponder receptor, and its integration with the others systems. Some microstrip filters architectures have been studied, aiming the viability of implementation and suitable practical application for the purposes of the ITASAT Project due to its lowspace occupation in the lower UHF frequencies. The ITASAT project is a Universityexperimental project which will build a satellite to integrate the Brazilian Data Collect System s satellite constellation, with efforts of many Brazilian institutes, like for example AEB (Brazilian Spatial Agency), ITA (Technological Institute of Aeronautics), INPE/CRN (National Institute of Spatial Researches/Northeastern Regional Center) and UFRN (Federal University of Rio Grande do Norte). Comparisons were made between numerical and experimental results of all filters, where good agreements could be noticed, reaching the most of the objectives. Also, post-work improvements were suggested.

Controle vetorial para velocidade de um motor de indução trifásico utilizando estimador filtro de Kalman

This paper describes the study, computer simulation and feasibility of implementation of vector control speed of an induction motor using for this purpose the Extended Kalman Filter as an estimator of rotor flux. The motivation for such work is the use of a control system that requires no sensors on the machine shaft, thus providing a considerable cost reduction of drives and their maintenance, increased reliability, robustness and noise immunity as compared to control systems with conventional sensors

Mudanças climáticas globais e o compromisso pró-ecológico de adolescentes natalenses

In recent years, much has been discussed about global climate changes (GCCs), popularly known as global warming. The scientific evidences point out to the influence of human actions for its drastic intensification. Therefore, studies of the psychological aspects involved become relevant. This study aimed at the investigation of the views of adolescents concerning GCCs, and the possible relations between those views and their pro-ecological commitment. Such commitment is measured by willingness for engagement in pro-environmental behaviors; environmentalism attitudes, like ecocentric and anthropocentric; consideration of future consequences; and ecological worldviews. Participants were 348 adolescents who answered a questionnaire containing questions about socio-demographic data, open questions about the practice of environmental care, and about GCCs, and the scales of Ecocentric and Anthropocentric Environmentalism, the Consideration of Future Consequences and the Ecological Worldviews assessment scale. From the inter-relationships between variables, procedures carried out by means of descriptive and correlacional statistics, it was observed that 55% of teenagers said that they did not engage in actions of environmental care, which was associated with apathyanthropocentric, immediatism, and individualism. The consideration of future consequences joined the practice of environmental care, corroborating evidence from the literature. It was evident that views concerning GCCs were superficial; adolescents perceive it as a generic environmental problem, and are confused with other problems such as pollution. This study found no association between views about GCCs and the indicators of pro-ecological commitment, perhaps due to the conceptual confusion about the subject. However, the lack of environmental care actions and other indicators of non-commitment (apathy-anthropocentric, individualism and immediatism) were associated with conceptually poor or incomplete responses (with no indication of cause, consequence or responsibility for the problem), demonstrating diminished knowledge and the failure to consider these issues

Otimização em comitês de classificadores: uma abordagem baseada em filtro para seleção de subconjuntos de atributos

Traditional applications of feature selection in areas such as data mining, machine learning and pattern recognition aim to improve the accuracy and to reduce the computational cost of the model. It is done through the removal of redundant, irrelevant or noisy data, finding a representative subset of data that reduces its dimensionality without loss of performance. With the development of research in ensemble of classifiers and the verification that this type of model has better performance than the individual models, if the base classifiers are diverse, comes a new field of application to the research of feature selection. In this new field, it is desired to find diverse subsets of features for the construction of base classifiers for the ensemble systems. This work proposes an approach that maximizes the diversity of the ensembles by selecting subsets of features using a model independent of the learning algorithm and with low computational cost. This is done using bio-inspired metaheuristics with evaluation filter-based criteria

Contribuições à estratégia de controle sem detecção de harmônicos aplicada a um filtro ativo de potência paralelo

The conventional control schemes applied to Shunt Active Power Filters (SAPF) are Harmonic extractor-based strategies (HEBSs) because their effectiveness depends on how quickly and accurately the harmonic components of the nonlinear loads are identified. The SAPF can be also implemented without the use of the load harmonic extractors. In this case, the harmonic compensating term is obtained from the system active power balance. These systems can be considered as balanced-energy-based schemes (BEBSs) and their performance depends on how fast the system reaches the equilibrium state. In this case, the phase currents of the power grid are indirectly regulated by double sequence controllers with two degrees of freedom, where the internal model principle is employed to avoid reference frame transformation. Additionally the DSC controller presents robustness when the SAPF is operating under unbalanced conditions. Furthermore, SAPF implemented without harmonic detection schemes compensate simultaneously harmonic distortion and reactive power of the load. Their compensation capabilities, however, are limited by the SAPF power converter rating. Such a restriction can be minimized if the level of the reactive power correction is managed. In this work an estimation scheme for determining the filter currents is introduced to manage the compensation of reactive power. Experimental results are shown for demonstrating the performance of the proposed SAPF system.

Experiências de vida e a formação do compromisso pró-ecológico

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES

A predominância do filtro ambiental local na montagem de uma floresta tropical de ambiente estressante

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Obtenção de filtro cerâmico a partir da diatomita e casca de arroz carbonizada visando tratamento de efluente têxtil

The effluents released by the textile industry have high concentrations of alkali, carbohydrates, proteins, in addition to colors containing heavy metals. Therefore, a filter was prepared aiming primarily to the removal of color. In order to prepare this filter, rice hulls and diatomite were used, which have in their structure, basically amorphous hydrated silica. The silica exists in three crystalline forms: quartz, tridymite and cristobalite. In accordance with the above considerations, this study was divided into two stages; the first corresponds to the preparation of the filter and the second to carry out the tests in the effluent/filter in order to verify the efficiency of the color removal. First, the raw material was subjected to a chemical analysis and XRD, and then the diatomite was mixed, via humid, with a planetarium windmill with 20 %, 40 %, 60 % and 80 % of rice husk ash. To the mixture, 5 % carboxymethylcellulose (CMC) was added as a binder at room temperature. The samples were uniaxially compacted into metallic matrix of 0.3 x 0.1 cm² of area at a pressure of 167 MPa by means of hydraulic press and then sintered at temperatures of 1,000 °C, 1,200 °C and 1,400 °C for 1 h and submitted to granulometry test using laser, linear retraction, water absorption, apparent porosity and resistance to bending, DTA, TMA and XRD. To examine the pore structure of the samples scanning electron microscope (SEM) was used. Also tests were carried out in a mercury porosimeter to verify the average size of the pores and real density of the samples. In the second stage, samples of the effluent were collected from a local industry, whose name will be preserved, located in Igapó, in the State of Rio Grande do Norte - RN. The effluent was first pretreated before filtration and then subjected to a treatment of flotation. The effluent was then characterized before and after filtration, with parameters of color, turbidity, suspended solids, pH, chemical and biochemical oxygen demand (COD and BOD). Thus, through the XRD analysis the formation of cristobalite α in all samples was observed. The best average size of pore was found to be 1.75 μm with 61.04 % apparent porosity, thus obtaining an average 97.9 % color removal and 99.8 % removal of suspended solid

Filtro kl/dvs para atenuação do ruído "ground roll"

In geophysics there are several steps in the study of the Earth, one of them is the processing of seismic records. These records are obtained through observations made on the earth surface and are useful for information about the structure and composition of the inaccessible parts in great depths. Most of the tools and techniques developed for such studies has been applied in academic projects. The big problem is that the seismic processing power unwanted, recorded by receivers that do not bring any kind of information related to the reflectors can mask the information and/or generate erroneous information from the subsurface. This energy is known as unwanted seismic noise. To reduce the noise and improve a signal indicating a reflection, without losing desirable signals is sometimes a problem of difficult solution. The project aims to get rid of the ground roll noise, which shows a pattern characterized by low frequency, low rate of decay, low velocity and high amplituds. The Karhunen-Loève Transform is a great tool for identification of patterns based on the eigenvalues and eigenvectors. Together with the Karhunen-Loève Transform we will be using the Singular Value Decomposition, since it is a great mathematical technique for manipulating data