Identificação das condições gerais de conservação dos reservatórios integrantes do sistema de abastecimento de água de Natal

Infrastructure works are included in strategic areas for the social development. For that matter that all of the investments are very important for the social development. When the population has enough water and an acceptable quality, and it includes a wastewater gathering and its treatment, the whole society became less susceptible to the water diseases. Even the Water Supply and the Sewage depend for its perfect operation of reservoirs, or of the accumulation of water to provide the popular necessity, either due to retention or for the treatment wastewarer. These structures present very specific environmental conditions, because the microclimate created around them, like high environmental humidity and for the existence of many harmful substances for the concrete, such as chloride ions presents in water. The reservoir that compose the System of Water Supply of Natal were built between 1970s and 1980s, a period whom the technical and scientific community did not have in-depth studies about the reinforced concrete mechanism of deterioration. Therefore, these reservoirs have been suffered accelerated deterioration progress, and they have been shown many pathological manifestations strikingly visible. In front of all these problems this academic work aims to identify the generally conditions of conservation of all the reservoirs components of the Water Supply System of Natal. This academic work objectives to develop a recuperation plan for use in these reservoirs, in this academic work it was achieved all the survey of pathological manifestation existing in each reservoir. It was made with local visits, photographic recorders of all manifestations viii and realization of in loco tests. The other step consisted in a application of GDE/UnB metodolgy reformulated by Fonseca (2007). In the step of local visits in each reservoir it was evaluated carbonation depth, by spreading a phenolphthalein solution with 1% of concentration; evaluation of contamination of chlorides, by spreading silver nitrate solution with 1% of concentration, and evaluation of width cracks. After the conclusion of all the testings, it was established that all reservoir, studied in this academic work, have showed an advanced deteriorating condition. It´s presents prevalent pathological manifestations as unacceptable cracks, spots, efflorescence and reinforcement corrosion, and in some cases, chlorides contamination. After the conclusion of the testings and its concatenation it was able to implementing, using GDE/UnB methodology, the order of the restoration its service life and initial safety conditions

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.

Influência da absorção de umidade no comportamento mecânico nos compósitos poliméricos híbridos Kevlar/vidro quando imerso em água do mar e petróleo

The polymer matrix composite materials are being used on a large scale in the most different industrial fields such as aerospace, automotive, oil, among others, since the industrial perspectives is currently working with materials which have a good mechanical performance at high service life and cost / benefit. Thus, the determination of the mechanical properties is indispensable for the characterization of waste resulting in greater expansion of this type of material. Thus, this work will be obtained three plates laminated with tereftálica polymeric matrix reinforced by a bidirectional woven E-glass and kevlar both industrially made, where the plates are manufactured by manual lamination process (hand lay-up), all laminates have five enhancement layers, the first hybrid laminate will consist of bidirectional woven E-glass fiber, kevlar fiber interspersed with layers, is formed by the second bidirectional woven kevlar fiber at the ends of the laminate (two layers), and in the center the glass fiber fabric (three layers), the third plate is composed of only the bidirectional woven E-glass fiber. Then were prepared specimens (CP) by standard, to determine the mechanical properties of tensile and bending in three points. After fabrication of the specimens, they were immersed in oil and seawater. After that, there was a comparison of the mechanical properties for the test condition in the dry state. Showing that there was a considerable increase in the properties studied because the effect of hybridization in laminates.

Análise topológica experimental por perfilometria cíclica indutiva de superficies de paredes estruturais

To enhance the maintenance practices, Oil and Gas Pipelines are inspected from the inside by automated systems called PIG (Pipeline Inspection Gauge). The inspection and mapping of defects, as dents and holes, in the internal wall of these pipelines are increasingly put into service toward an overall Structural Integrity Policy. The residual life of these structures must be determined such that minimize its probability of failure. For this reason, the investigation on the detection limits of some basic topological features constituted by peaks or valleys disposed along a smooth surface is of great value for determining the sensitivity of the measurements of defects from some combinations of circumferential, axial and radial extent. In this investigation, it was analyzed an inductive profilometric sensor to scan three races, radius r1, r2, r3, in a circular surface of low carbon steel, equipped with eight consecutive defects simulated by bulges and holes by orbit, equally spaced at p/4 rad. A test rig and a methodology for testing in laboratory were developed to evaluate the sensor response and identify their dead zones and jumps due to fluctuations as a function of topological features and scanning velocity, four speeds different. The results are presented, analyzed and suggestions are made toward a new conception of sensor topologies, more sensible to detect these type of damage morphologies