Image registration and image interpolation in volume rendering of cross sections

We outline a method for registration of images of cross sections using the concepts of The Generalized Hough Transform (GHT). The approach may be useful in situations where automation should be a concern. To overcome known problems of noise of traditional GHT we have implemented a slight modified version of the basic algorithm. The modification consists of eliminating points of no interest in the process before the application of the accumulation step of the algorithm. This procedure minimizes the amount of accumulation points while reducing the probability of appearing of spurious peaks. Also, we apply image warping techniques to interpolate images among cross sections. This is needed where the distance of samples between sections is too large. Then it is suggested that the step of registration with GHT can help the interpolation automation by simplifying the correspondence between points of images. Some results are shown.

New species of Eleutherodactylus (Amphibia: Leptodactylidae) from Guaraquecaba, Atlantic Forest of Brazil

A new species of the leptodactylid frog genus Eleutherodactylus is described from Guaraquecaba, State of Parana, southern Brazil. The new species is characterized by its large size, slightly rugose to rugose dorsal skin texture, robust body, and low number of pulses per call. Descriptions of the advertisement calls of the new species and of E. manezinho, a close related species, are provided, as well as information on natural history.

Sintering of cobalt and strontium doped lanthanum chromite obtained by combustion synthesis

Lanthanum chromite (LaCrO3) is one of the most adequate materials for use as interconnector in solid oxide fuel cell (SOFC) applications, due to its intrinsic properties, namely its good electrical conductivity and resistance to environment conditions in fuel cell operations. Due to difficulties in sintering, additives are usually added to help in the densification process. In this work, the influence of added cobalt and strontium, in the sintering of LaCrO3 obtained by combustion synthesis was studied. The starting materials were respectively nitrates of chromium, lanthanum, cobalt and strontium, and urea was used as fuel. The results show that by increasing the strontium and cobalt concentrations it is possible to reduce the temperature of sintering. Using both additives, the sintering processes took place in lesser times than normally used for this material, as well as greater values of density were attained.

Optimization of multipulse converters with delta and Y-differential connections

This work presents a study regarding the optimization of multipulse converters. A general expression for the connection (Δ or Y) for both 12 and 18-pulses is obtained and describes the output voltages on the secondary windings, depending on the voltage reference from the primary. These generalized expressions allows choosing different ratios between input and output voltages and as result an optimum operation point for the converter can be calculated. Considering Δ-connected converters the optimum point occurs when the magnetic core of the autotransformer processes 18% and 17% of the output power for 12 and 18-pulses, respectively. For Y-connected converters the optimum point occurs when the kVA rating is 13% and 18% for 12 and 18-pulses, respectively. Based on these results magnetic elements can be calculated and designed leading to a great weight and volume reduction and also to lower costs and losses. Finally an analysis is made to improve the kVA rating of the transformers for 12 and 18 pulses converters. © 2009 IEEE.

Avaliação preliminar do potencial turístico do município de rifaina (SP) e os impactos decorrentes do uso público de seus atrativos paisagísticos

This paper attempts to assess both the touristic potential of scenic attractions and the environmental impacts resulting from the public use of such attractions in the Rifaina Municipality, State of São Paulo, Southeastern Brazil. In the recent past, this municipality had its economy concentrated in rural activities (livestock, corn, rice and bean crops) and in the ceramic industry (production of bricks, tiles and shackles),which was largely developed in the floodplain of the Rio Grande before the construction of the Jaguara Power Plant Dam. The impacts resulting from touristic activities were evaluated by applying the VIM - Visitor Impact Management method, with emphasis on biophysical indicators. The main touristic attractions analyzed were: (1) Rifaina artificial beach; (2) Jaguara Reservoir; (3) Morro do Chapéu (scenic hill); (4) Touristic railroad; and (5) Cuestas cliffs. Attractions (1) and (2) are the most exploited ones, including, in the second case, nautical sports, sportive and craft fishing, and summer lodging. Although currently disabled, the touristic railroad presents potential conditions to be re-explored. Attractions (3) and (5), despite keeping high landscape and ecological ecotouristic potential, are the least visited places. In the present paper, a preliminary characterization of the major issues of tourism industry in the Rifaina municipality is made, including suggestions for the sustainable exploitation of tourism resources. The final results of the environmental impact evaluation of the tourism activities include small impacts in attractions (4) and (5) and moderate impacts to the three first attractions. In order to keep the sustainable touristic potential for that municipality this study proposes the improvement of the following measures: to foster research projects on technical or scientific aspects of the touristic attractions, improvement of tourism infrastructure and the creation of an Environmental Protection Area (APA) of the cuestas' scarps.

Influence of the coloring agent concentration on bleaching gel and pulp chamber temperatures during dental bleaching

This study evaluated the Influence of the coloring agent concentration on the temperature of the gel layer and pulp chamber during dental bleaching with an LED/laser light source. Ten human incisors and a digital thermometer with K-type thermocouples were used. Using a high-speed spherical diamond bur, endodontic access was gained through openings on the lingual faces until pulp chamber was exposed. One end of the thermocouple was placed on the labial surface (immersed in bleaching gel) and the other end in the pulp chamber. The same 10 specimens were used in the 12 groups, according to the type and concentration of bleaching gel. Each bleaching gel was used in four different concentrations: manipulated without coloring, with normal quantity recommended by the manufacturer, with double the recommended amount of coloring, and with triple the recommended amount of coloring. The temperature rise was measured every 30 seconds for three minutes with a K-type thermocouple. The data were analyzed by ANOVA to examine the concentration and type of bleaching gel. This test was followed by Tukey's test, which was performed Independently for the gel at the labial surface and the pulp chamber (a = 5%). For both surfaces, values of p = 0.00 were obtained for all factors and for the Interaction between them. The varying concentrations of coloring agent produced statistically significant differences in terms of temperature increase for both the gel layer and the pulp chamber during activation.

Caracterização morfológica do fruto, semente e morfofunção de plântulas de sapoteira-preta (Diospyros ebenaster Retz.)

Diospyros ebenaster, originária do México e América Central, família Ebenaceae, é conhecida como sapota-preta. Os frutos podem ser consumidos in natura ou em sucos, como fonte de vitamina C. O objetivo deste trabalho foi caracterizar a morfologia do fruto, da semente e do processo germinativo da espécie. Os frutos foram caracterizados quanto à coloração, textura, consistência e teor de água no pericarpo, deiscência, massa, partes constituintes e dimensões. Para as sementes considerou-se: Massa, coloração, textura e consistência do tegumento, forma, presença e tipo de tecido de reserva e tipo, coloração, forma e posição do embrião. A descrição das plântulas foi realizada a partir da emissão da raiz primária até a expansão dos primeiros eófilos e início de fenecimento dos cotilédones. O fruto é carnoso, indeiscente, do tipo baga, polispérmico, globoso e achatado nos pólos. O epicarpo é liso, delgado e esverdeado. O comprimento médio dos frutos é 8,8 cm, o diâmetro médio 8,6 cm e a massa de 263 g. As sementes apresentam tegumento liso e cor castanho-médio. A massa de 100 sementes é 100,6 g. O comprimento médio das sementes é 2,2 cm, com 1,3 cm de largura. Possuem endosperma branco-Transparente e oleaginoso. O embrião é esbranquiçado e a germinação é epígea.

Família de retificadores multipulsos com topologias diferenciais de transformadores

Multipulse rectifier topologies based on auto-connections or differential connections, are more and more applied as interface stages between the mains and power converters. These topologies are becoming increasingly attractive not only for robustness, but to mitigate many low order current harmonics in the utility, reducing the total harmonic distortion of the line currents (THDi) and increasing the power factor requirements. Unlike isolated connections (delta-wye, zigzag, etc.), when the differential transformer is employed, most of the energy required by the load is directly conducted through the windings. Thus, only a small fraction of the kVA is processed by the magnetic core. This feature increases the power density of the converter. This paper presents a mathematical model based on phasor diagrams, which results in a single expression able to merge all differential connections (wye and delta), for both step-up and step-down rectifiers for 12 or 18 pulses. The proposed family of converters can be designed for any relationship between the line input voltage and the DC voltage, unlike the conventional phase-shift voltage connections. An immediate application would be the retrofit, i.e. to replace a conventional rectifier with poor quality of the processed energy by the 12 or 18-pulse rectifiers with Wye or Delta-differential connections, keeping the original values for the input and load voltages. The simple and fast design procedure is developed and tested for a prototype rating 6 kW and 400 V on DC load.

AC-DC three-phase multipulse converter with boost DC-DC stage and constant hysteresis control

This work proposes a new three-phase multipulse rectifier based on the delta autotransformer connection with DC-DC Boost stages and constant hysteresis control which has the objective of providing a reliable DC bus for on-board applications, electric motor drives and similars, always considering power quality issues. Thus, the proposal presents 0.99 power factor, 6% harmonic distortions in the currents from the mains and enhanced magnetic core utilization, which results in low weight and volume for the overall converter. The proposed control technique uses the simple constant hysteresis concept, thus leading to a low-cost but effective and reliable strategy. © 2011 IEEE.

A visual tool for building synchronous generator capability curves

Synchronous generators are essential components of electric power systems. They are present both in hydro and thermal power plants, performing the function of converting mechanical into electrical energy. This paper presents a visual approach to manipulate parameters that affect operation limits of synchronous generators, using a specifically designed software. The operating characteristics of synchronous generators, for all possible modes of operation, are revised in order to link the concepts to the graphic objects. The approach matches the distance learning tool requirements and also enriches the learning process by developing student trust and understanding of the concepts involved in building synchronous machine capability curves. © 2012 IEEE.

RBPI21 interacts with negative membranes endothermically promoting the formation of rigid multilamellar structures

rBPI21 belongs to the antimicrobial peptide and protein (AMP) family. It has high affinity for lipopolysaccharide (LPS), acting mainly against Gram-negative bacteria. This work intends to elucidate the mechanism of action of rBPI21 at the membrane level. Using isothermal titration calorimetry, we observed that rBPI21 interaction occurs only with negatively charged membranes (mimicking bacterial membranes) and is entropically driven. Differential scanning calorimetry shows that membrane interaction with rBPI21 is followed by an increase of rigidity on negatively charged membrane, which is corroborated by small angle X-ray scattering (SAXS). Additionally, SAXS data reveal that rBPI21 promotes the multilamellarization of negatively charged membranes. The results support the proposed model for rBPI21 action: first it may interact with LPS at the bacterial surface. This entropic interaction could cause the release of ions that maintain the packed structure of LPS, ensuring peptide penetration. Then, rBPI21 may interact with the negatively charged leaflets of the outer and inner membranes, promoting the interaction between the two bacterial membranes, ultimately leading to cell death. © 2013 Elsevier B.V.

Avaliação limnológica em um sistema de piscicultura na região de Paranaíta (MT, Brasil)

Pós-graduação em Aquicultura - FCAV

Retificador trifásico de 18 pulsos com estágio CC controlado por histerese constante

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Morfologia, ultraestrutura e morfometria do tegumento da paca (Cuniculus paca)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)