Suitability of carbon fiber-reinforced polymers as power cable cores: Galvanic corrosion and thermal stability evaluation

The increasing demand for electrical energy and the difficulties involved in installing new transmission lines presents a global challenge. Transmission line cables need to conduct more current, which creates the problem of excessive cable sag and limits the distance between towers. Therefore, it is necessary to develop new cables that have low thermal expansion coefficients, low densities, and high resistance to mechanical stress and corrosion. Continuous fiber-reinforced polymers are now widely used in many industries, including electrical utilities, and provide properties that are superior to those of traditional ACSR (aluminum conductor steel reinforced) cables. Although composite core cables show good performance in terms of corrosion, the contact of carbon fibers with aluminum promotes galvanic corrosion, which compromises mechanical performance. In this work, three different fiber coatings were tested (phenol formaldehyde resin, epoxy-based resin, and epoxy resin with polyester braiding), with measurements of the galvanic current. The use of epoxy resin combined with polyester braiding provided the best inhibition of galvanic corrosion. Investigation of thermal stability revealed that use of phenol formaldehyde resin resulted in a higher glass transition temperature. On the other hand, a post-cure process applied to epoxy-based resin enabled it to achieve glass transition temperatures of up to 200 degrees C. (C) 2014 Elsevier Ltd. All rights reserved.

O risco ambiental representado por campos eletromagnéticos em Presidente Prudente (SP)

Currently the mobile services represent an essential tool in daily life of the population. However, while offering greater convenience to its users, there is growing concern about the harmful effects to human health, derived from daily exposure of the public to electromagnetic fields from radio base stations (RBS), since even today, there is no study proving that longterm exposure to low-level fields are not harmful to health. In Presidente Prudente has not been a study reporting values of measurements of electromagnetic fields from base stations installed in the city. Based on these data, this study aimed to assess the levels of electromagnetic exposure in the city of Presidente Prudente regarding recommended by international bodies, as well as propose measures that can reduce public exposure to electromagnetic fields. For measuring values of electromagnetic fields, we used appliance Electromagnetic Field Meter Portable Digital - DRE-050, the Instrutherm, following the methodology suggested and adapted from the Adilza Condessa Dode’study. In total, 49 points were mapped corresponding to the areas at risk of exposure to electromagnetic fields generated by the substations of power grid, transmission towers and telecommunication towers located in the city of Presidente Prudente (SP)

Cinética de degradação do sistema resina epóxi/fibra de carbono

With the increasing demand for electricity, the retraining of transmission lines is necessary despite environmental restrictions and crossings in densely populated areas to build new transmission and distribution lines. Solution is reuse the existent cables, replacing the old conductor cables for new cables with higher capacity power transmission, and control of sag installed. The increasing demand for electrical power has increased the electric current on the wires and therefore, it must bear out temperatures of 150°C or more, without the risk of the increasing sag beyond the established limits. In the case of long crossings or densely populated areas, sag is due to high weight of the cable on clearance. The cable type determines the weight, sag, height and the towers dimensions, which are the items that most influence the investment of the transmission line. Hence, to reduce both cost of investment and maintenance of the line, the use of a lighter cable can reduce both number and the height of the towers, with financial return on short and long term. Therefore, in order to increase the amount of transmitted energy and reduce the number of built towers and sag, is recommended in the current work substitute the current core material (steel or aluminium) for alternatives alloys or new materials, in this case a composite, which has low density, elevated stiffness (elasticity module), thus apply the pultruded carbon fiber with epoxy resin as matrix systems and perform the study of the kinetics of degradation by thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA) and differential scanning calorimetry (DSC), according to their respective standards

Comparação de custo e viabilidade técnica de obras com parede de concreto em relação a obras de alvenaria estrutural

Are being released in the construction market in Brazil ventures called Super 6. These businesses sell the promise of delivery of the apartment in six months after the launch of the venture. To meet this deadline are being deployed the constructive method of concrete walls using aluminum shapes. This system basically consists of pouring slabs and walls once, i.e. building up the wall shapes and slab joints. On the walls are used cloth, with reinforcements in vain and corners of walls and on these screens are tied the electrical boxes and conduits. For each tower is used the so-called system of half way, i.e. the system so it is sufficient to mount the Middle deck. Using a concrete which can be deformed in the next day you can lift one deck every two days with ready electric and hydraulicsystem, without having to tow the wall doing only minor fixes in the imperfections after concrete. With this system won an incredible speed in the construction of the structure reducing in almost one-third the length of the work. This work aims to compare in terms of cost-benefit of masonry structural systems and this new concrete wall system called Super 6. For this comparison will be used as parameter values used for the achievement of the Enterprise Portal of Roses of constructor Tenda which is one of the first to use concrete wall system. This project basically consists of seven towers of six floors each and will be budgeted the cost of this project if it were held in structural masonry. From these data it will be possible to make a comparison about the actual beneficial to adopt this system

Avaliação de sistemas de pultrudados com diferentes tipos de matrizes para aplicação em cabos condutores

In the last decades it has been observed a substantial developing of the electrical energy demand in the societies all over the World. In consequence the electrical energy distribution companies are increasing the quantity of electrical energy through the electrical energy conductor cables, which had grown the sag in the towers of energy transmission. Furthermore, the construction of more transmission towers brings a lot of troubles due environmental protection laws. In this way, looking forward to increase the quantity of electrical energy transmitted through electrical cables conductors, reduce the need of constructing new transmission towers and the sag in them, we suggest in this work the replace of the traditional core of the conductors cables commonly used, made of steel, by a core made by a composite material, which one is made by carbon fibers pultruded with polymeric resins as matrix. In a order to evaluate if the resins more commonly used in structural composites can be applied as matrix to make possible to use the composite material as a core, we made carbon fibers systems pultruded with epoxy, phenolic and polyester resins as matrix and a mechanic and physic-chemistry characterization was done on the systems by Tensile and Poisson tests, differential sprobe calorimetry (DSC), thermogravimetric analysis (TGA) and Fourier transformed infrared spectroscopy (FTIR), following their correspondents standards

Caracterização morfológica e fenotípica de leveduras do gênero Cryptococcus com ênfase na pesquisa de Cryptococcus neoormans isoladas de amostras de água de mar e areia de três ambientes costeiros do estado de São Paulo: Canal de São Sebastião, Baixada Santista e Ubatuba

The yeast Cryptococcus neoformans is the etiologic agent of cryptococcosis, an infectious cosmopolitan disease that affects humans. Although rare, this disease is potentially fatal, especially for immunocompromised hosts. This pathogen is frequently isolated from excrements of pigeons and parrots, with many environmental sources such as birds, pigeon droppings, eucalyptus leaves, decaying trees, towers, churches and places of storage of grain (the port area). The isolation of this microorganism has been obtained also from the aquatic environment. The identification of environmental sources is needed to protect human health, especially susceptible populations such as immunocompromised. Therefore, this study investigated the presence of Cryptococcus neoformans in yeast isolates obtained from samples of sea water and sand from three regions of São Paulo: São Sebastião Channel, Santos and Ubatuba. Isolates were analyzed according to micro-and macroscopic characteristics and biochemical tests: microculture, urease, ink nankin, auxanograma, zymogram and phenol. We analyzed 199 isolates, 175 of which had features suggestive for Cryptococcus spp. in microculture. All these 175 isolates were sown in the Christensen urea middle to verify the production of urease and submitted to the technique nankin ink to visualize the capsule. Of these, only 24 were selected for the next test that was the auxanograma (assimilation of carbohydrate and nitrogen). Of the 24, 10 were tested in zymograms (fermented sugar), from which 5 were selected for the phenoloxidase test in medium containing dopamine. None of the 5 isolates tested had black or brown color characteristic of Cryptococcus neoformans. According to these tests, we arrived at 5 isolates identified to the genus Cryptococcus, but not the neoformans specie

Torres de extensões abelianas de grau primo ímpar não ramificado

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Monitoramento de raças de Bremia lactucae em alface no ano de 2014 e sua distribuição no Estado de São Paulo

Pós-graduação em Agronomia (Genética e Melhoramento de Plantas) - FCAV

Elaboração de um roteiro interpretativo para trilha de ciclista da Florestal Estadual Edmundo Navarro de Andrade, Rio Claro/SP

The State Forest Edmundo Navarro de Andrade (FEENA), Rio Claro/SP has a huge potential for cyclists tracks; the Unit already have a trail at the principal entrance, passing by firebreaks bordering the towers quadrants and finishing at the municipal road. This work aims the ambiental interpretation of this trail already established and implant activities planned before at the public use program of the State Forest according to the management plan of the Unit; to interpret the tracks for mountain bike cyclists; promote the conservation of natural, historic and cultural resources of the Forest. At the present work has been accomplished the Ambiental Interpretation through the panels, containing the characteristic native flora and fauna, the existing water resources at the Unit and also the representatives individuals of the exotic arboreal species, found around the trail. Ten points were chosen for interpretation, therefore, for preparation of the script it was considered besides the bibliographic literature, experiences of project team members at FEENA, Unit Management Plan knowledge relating the gaps in the public use program and field work. The panels contain figures and texts about the chosen topics, to promote a language easily understandable to the visitor and concomitantly, inform to the population who attends the Unit, increasing this way the user satisfaction

Considerações sobre a análise de segunda ordem de estais utilizados em torres metálicas e flares

This work is consideration of an analysis of second-order (nonlinear analysis) applied to e metal towers and flares. The analysis is mainly done using the wind efforts and the weight of the structure. The analysis itself is carried out with the aid of a structural analysis software, SAP2000 where two proposes modeling. The first for the linear effects and the second for the nonlinear effects