966 resultados para Falha de equipamento
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The technical and economic viability of solar heating for swimming pools is unquestionable, besides there it replaces the high costs and environmental impacts of conventional supply of energy, and it improves an optimization in the pool heating uses. This work applies the principles of the greenhouse effect: advanced thermodynamics, heat retention and equalization of temperature, to optimize the solar heating equipment, reducing the area required by collectors as much as 40% (still estimated value) for commercial collectors, with minor architectural and aesthetic impacts on the environment. It features a solar heating alternative in pools, whose main characteristics: low cost, simplicity in manufacturing and assembly and a faster heating. The system consists of two collectors spiral hoses made of polyethylene with a hundred meters each, and working on a forced flow, with only one pass of the working fluid inside the coils, and is used to pump itself treatment of pool water to obtain the desired flow. One of the collectors will be exposed to direct solar radiation, and the other will be covered by a glass slide and closed laterally, so providing the greenhouse effect. The equipment will be installed in parallel and simultaneously exposed to the sun in order to obtain comparative data on their effectiveness. Will be presented results of thermal tests for this the two cases, with and without transparent cover. Will be demonstrated, by comparison, the thermal, economic and material feasibility of these systems for heating swimming pools.
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New materials made from industrial wastes have been studied as an alternative to traditional fabrication processes in building and civil engineering. These materials are produced considering some issues like: cost, efficiency and reduction of nvironmental damage. Specifically in cases of materials destined to dwellings in low latitude regions, like Brazilian Northeast, efficiency is related to mechanical and thermal resistance. Thus, when thermal insulation and energetic efficiency are aimed, it s important to increase thermal resistance without depletion of mechanical properties. This research was conducted on a construction element made of two plates of cement mortar, interspersed with a plate of recycled expanded polystyrene (EPS). This component, widely known as sandwich-panel, is commonly manufactured with commercial EPS whose substitution was proposed in this study. For this purpose it was applied a detailed methodology that defines parameters to a rational batching of the elements that constitute the nucleus. Samples of recycled EPS were made in two different values of apparent specific mass (ρ = 65 kg/m³; ρ = 130 kg/m³) and submitted to the Quick-Line 30TM that is a thermophysical properties analyzer. Based on the results of thermal conductivity, thermal capacity and thermal diffusivity obtained, it was possible to assure that recycled EPS has thermal insulation characteristics that qualify it to replace commercial EPS in building and civil engineering industry
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The competitiveness of the trade generated by the higher availability of products with lower quality and cost promoted a new reality of industrial production with small clearances. Track deviations at the production are not discarded, uncertainties can statistically occur. The world consumer and the Brazilian one are supported by the consumer protection code, in lawsuits against the products poor quality. An automobile is composed of various systems and thousands of constituent parts, increasing the likelihood of failure. The dynamic and security systems are critical in relation to the consequences of possible failures. The investigation of the failure gives us the possibility of learning and contributing to various improvements. Our main purpose in this work is to develop a systematic, specific methodology by investigating the root cause of the flaw occurred on an axle end of the front suspension of an automobile, and to perform comparative data analyses between the fractured part and the project information. Our research was based on a flaw generated in an automotive suspension system involved in a mechanical judicial cause, resulting in property and personal damages. In the investigations concerning the analysis of mechanical flaws, knowledge on materials engineering plays a crucial role in the process, since it enables applying techniques for characterizing materials, relating the technical attributes required from a respective part with its structure of manufacturing material, thus providing a greater scientific contribution to the work. The specific methodology developed follows its own flowchart. In the early phase, the data in the records and information on the involved ones were collected. The following laboratory analyses were performed: macrography of the fracture, micrography with SEM (Scanning Electron Microscope) of the initial and final fracture, phase analysis with optical microscopy, Brinell hardness and Vickers microhardness analyses, quantitative and qualitative chemical analysis, by using X-ray fluorescence and optical spectroscopy for carbon analysis, qualitative study on the state of tension was done. Field data were also collected. In the analyses data of the values resulting from the fractured stock parts and the design values were compared. After the investigation, one concluded that: the developed methodology systematized the investigation and enabled crossing data, thus minimizing diagnostic error probability, the morphology of the fracture indicates failure by the fatigue mechanism in a geometrically propitious location, a tension hub, the part was subjected to low tensions by the sectional area of the final fracture, the manufacturing material of the fractured part has low ductility, the component fractured in an earlier moment than the one recommended by the manufacturer, the percentages of C, Si, Mn and Cr of the fractured part present values which differ from the design ones, the hardness value of the superior limit of the fractured part is higher than that of the design, and there is no manufacturing uniformity between stock and fractured part. The work will contribute to optimizing the guidance of the actions in a mechanical engineering judicial expertise
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This research this based on the seminar on Use of Natural Fluids in Refrigeration and Air-Conditioning Systems conducted in 2007 in Sao Paulo. The event was inserted in the National Plan for Elimination of CFCs, coordinated by the Ministry of Environment and implemented by the United Nations Development Programme (UNDP). The objective of this research is analyze the performance of the hydrocarbons application as zeotropic mixtures in domestic refrigerator and validate the application of technical standards for pull down and cycling (on-off) tests to the mixture R290/R600a (50:50) in domestic refrigerator. It was first developed an computational analysis of R290/R600a (50:50) compared to R134a and other mass fractions of the hydrocarbons mixtures in the standard ASHRAE refrigeration cycle in order to compare the operational characteristics and thermodynamic properties of fluids based on the software REFPROP 6.0. The characteristics of the Lorenz cycle is presented as an application directed to zeotropic mixtures. Standardized pull down and cycling (on-off) tests were conducted to evaluate the performance of the hydrocarbons mixture R290/R600a (50:50) as a drop-in alternative to R134a in domestic refrigerator of 219 L. The results showed that the use of R290/R600a (50:50) with a charge of refrigerant reduced at 53% compared to R134a presents reduced energy performance than R134a. The COP obtained with hydrocarbon mixture was about 13% lower compared to R134a. Pull down times in the refrigerator compartments for fluids analyzed were quite close, having been found a 4,7% reduction in pull down time for the R290/R600a compared to R134a, in the freezer compartment. The data indicated a higher consumption of electric current from the refrigerator when operating with the R290/R600a. The values were higher than about 3% compared to R134a. The charge of 40 g of R290/R600a proved very low for the equipment analyzed
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The oil industry`s need to produce with maximum efficiency, not to mention the safety and the environment aspects, encourages the optimization of processes. It makes them look for a level of excellence in acquisition of equipment, ensuring the quality without prejudice security of facilities and peoples. Knowing the reliability of equipment and that this stands for a system is fundamental to the production strategy to seeks the maximum return on investment. The reliability analysis techniques have been increasingly applied in the industry as strategy for predicting failures likelihood ensuring the integrity of processes. Some reliability theories underlie the decisions to use stochastic calculations to estimate equipment failure. This dissertation proposes two techniques associating qualitative (through expertise opinion) and quantitative data (European North Sea oil companies fault database, Ored) applied on centrifugal pump to water injection system for secondary oil recovery on two scenarios. The data were processed in reliability commercial software. As a result of hybridization, it was possible to determine the pump life cycle and what impact on production if it fails. The technique guides the best maintenance policy - important tool for strategic decisions on asset management.
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Wear mechanisms and thermal history of two non-conforming sliding surfaces was investigated in laboratory. A micro-abrasion testing setup was used but the traditional rotative sphere method was substituted by a cylindrical surface of revolution which included seven sharp angles varying between 15o to 180o. The micro-abrasion tests lead to the investigation on the polyurethane response at different contact pressures. For these turned counterfaces with and without heat treatment. Normal load and sliding speeds were changed. The sliding distance was fixed at 5 km in each test. The room and contact temperatures were measured during the tests. The polyurethane was characterized using tensile testing, hardness Shore A measurement, Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC) and Thermomechanical Analyze (TMA). The Vickers micro-hardness of the steel was measured before and after the heat treatment and the metallographic characterization was also carried out. Worn surface of polyurethane was analysed using Scanning Electron Microscope (SEM) and EDS (Electron Diffraction Scanning) microanalyses. Single pass scratch testing in polyurethane using indenters with different contact angles was also carried out. The scar morphology of the wear, the wear mechanism and the thermal response were analyzed in order to correlate the conditions imposed by the pressure-velocity pair to the materials in contact. Eight different wear mechanisms were identified on the polyurethane surface. It was found correlation between the temperature variation and the wear scar morphology.
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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
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The plasma produced by Dielectric Barrier Discharge (DBD) is a promising technique for producing plasma in atmospheric pressure and has been highlighted in several areas, especially in biomedical and textile industry, this is due to the fact that the plasma generated by DBD not reaches high temperatures, enabling use it for thermally sensitive materials. But still it is necessary the development of research related to understanding of the chemical, physical and biological interaction between the non-thermal plasma at atmospheric pressure with cells, tissues, organs and organisms. This work proposes to develop equipment DBD and characterize it in order to obtain a better understanding of the process parameters of plasma production and how it behaves under the parameters adopted in the process, such as distance, frequency and voltage applied between electrodes. For this purpose two techniques were used to characterize distinct from each other. The first was the method of Lissajous figures, this technique is quite effective and accurately for complete electrical characterization equipment DBD. The second technique used was Optical Emission Spectroscopy (EEO) very effective tool for the diagnosis of plasma with it being possible to identify the excited species present in the plasma produced. Finally comparing the data obtained by the two techniques was possible to identify a set of parameters that optimize the production when combined DBD plasma atmosphere in the equipment was built precisely in this condition 0.5mm-15kV 600Hz, giving way for further work
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Licuri is a palm tree from the semiarid regions of Bahia State, Brazil. It is an important source of food and feed in that region, since their nuts are commonly eaten by humans and used as maize substitute for poultry feeding. The aim of this dissertation is to study the feasibility for use of natural convection solar dryers and forced being compared with the traditional drying outdoors for drying coconut licuri Syagrus coronate. The study led to the construction of two prototype solar dryer for carrying out experiments proving: model Solar Drying System Direct Exposure to Natural Convection built with wood, has a drying chamber with direct cover transparent glass laminates 4 mm, using techniques for proper isolation of the drying chamber. The two prototypes were comparatively analyzed for performance and drying efficiency with traditional extractive use by the community. Were evaluated the variables: time and drying rates and quality of the final samples of coconut licuri. The fruits were harvested and brought the town of Ouricuri, in the city of Caldeirão Grande, BA for the experiments comparing the three methods of drying was used a standard load of 4.0 kg The quantitative analysis for the result of the drying rate was found in 74% yield and 44% for natural and forced convection respectively compared with the traditional drying. These drying rates represent variation 3-5 times lower. Drying using forced convection licuri showed better quality, was found in a reddish pulp, representing the quantities that were kept of the nutrient beta carotene, and not notice the flavor change from the previous system, the final cost of construction of this system were higher . The prototypes built competitive advantage and had testified fully to resolve the technical difficulties previously encountered in the production of products made of coconut licuri. Allowing add value and increase their potential use for the fruit extractive communities of semi-arid region of Bahia
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The technique of ion nitriding, despite being fully consolidated in the industry, has great limitations when applied to the treatment of small parts. This is because effects that occur due to non-uniformity of the electric field, generate localized heating in parts, damaging the uniformity of nitrided layer. In addition, because the samples are treated static parts thereof are untreated. To expand the use of plasma nitriding, this work presents the development, assembly and testing of a prototype plasma reactor with rotatory cathodic cage [patent pending], able to meet these needs, giving the material a uniform treatment and opening doors to industrial scale production. The samples tested with hexagonal nuts are 6.0 mm in diameter, made of stainless steel AISI 304 nitrided at a pressure of 1 mbar in an atmosphere of 20% H2 + 80% N2 for 1 h. After treatment, testing visual inspection, optical microscopy and microhardness were carried out to check the effectiveness of the process for uniformity and hardness of the parts. All samples exhibited uniform color, and matte brownish, unlike the untreated samples, silver color and gloss. The hardness of the surface (top and sides) was 65% and even higher than the original hardness. The nitrided layer showed great uniformity in microstructure and thickness. It is concluded, therefore, that the unit was effective constructed for the purposes for which it was designed
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Lubricant is responsible for reducing the wear on the friction protect the metal against oxidation, corrosion and dissipates excess heat, making it essential for the balance of a mechanical system, consequently prolonging the useful life of such a system. The origin of lubricating oils is usually mineral being extracted from the petroleum. But the search for a new source of production of lubricants and fuels it is necessary to meet future demands and reduce the possible environmental damage. For this reason, looking alternative means to produce certain products derived from petroleum, such as biodiesel, for example. Returning to the realm of lubricants, also one realizes this need for new raw materials for their production. Vegetable oil is a renewable resource and biodegradable, and its use entails advantages in environmental, social and economic. The development of this project aims to characterize the carnauba oil as a lubricant plant, or biolubricant. To analyze the oil carnauba tests as checking density, flash point, fire point, viscosity, viscosity, acid number, pH, copper corrosion, thermal conductivity and thermal resistivity were developed. In addition, for conducting the wear on the friction and the gradient of the system temperature, the analysis equipment is designed for wear on the friction. Based on these results, it is observed that the oil carnauba show good correlation to its application as biolubricant
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Currently, vegetable oils have been studied for bio-lubricants base that fits the new environmental standards. Since, in a world full of finite natural resources, mineral oils bring consequences to the environment due to its low biodegradability and toxicity, also it is important to consider that synthetic oils have a high cost The aim of this work is to obtain a biolubricant additived with oxide nanoparticles (ZnO and CuO) for better resistance to friction and wear, which is not toxic to the environment and have better adherence under boundary lubrication. The methodology consisted in the synthesis of bio-lubricants (soybean and sunflower base) by epoxidation reaction. Then, some physical-chemical analysis in bio-lubricants are made to characterize theses lubricants, such as, density, acidity, iodine value, viscosity, viscosity index. Later, the lubricants were additive with nanoparticles. The tribological performance was evaluated by the equipment HFRR (High Frequency Reciprocating Rig) consisting of a wear test ball-plan type. The characterization of wear analysis was performed by SEM / EDS. The results show that bio-lubricants may be synthesized by reaction of epoxidation with good conversion. Tribological point of view, the epoxidized oils are more effective than lubricant additived with the oxide nanoparticles, they had lower coefficients of friction and better rate of film formation in the study. However, because they are environmentally friendly, bio-lubricants gain the relevant importance in tribological field
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Improving the adherence between oilwell metallic casing and cement sheath potentially decrease the number of corrective actions present/y necessary for Northeastern wells submitted to steam injection. In addition to the direct costs involved in the corrective operations, the economic impact of the failure of the primary cementing aIso includes the loss in the production of the well. The adherence between casing and cement is current/y evaluated by a simple shear tests non standardized by the American Petroleum Institute (API). Therefore, the objective of the present is to propose and evaluate a standardized method to assess the adherence of oilwell metallic casing to cement sheath. To that end, a section of a cemented oilwell was simulated and used to test the effect of different parameters on the shear stress of the system. Surface roughness and different cement compositions submitted or not to thermal cycling were evaluated. The results revealed that the test geometry and parameters proposed yielded different values for the shear stress of the system, corresponding to different adherent conditions between metallic casing and cement sheath
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The use of the natural gas is growing year after year in the whole world and also in Brazil. It is verified that in the last five years the profile of natural gas consumption reached a great advance and investments had been carried through in this area. In the oil industry, the use of the natural gas for fuel in the drive of engines is usual for a long date. It is also used to put into motion equipment, or still, to generate electric power. Such engines are based on the motor cycle of combustion Otto, who requires a natural gas with well definite specification, conferring characteristic anti-detonating necessary to the equipment performance for projects based on this cycle. In this work, process routes and thermodynamic conditions had been selected and evaluated. Based on simulation assays carried out in commercial simulators the content of the methane index of the effluent gas were evaluated at various ranges of pressure, temperature, flowrate, molecular weight and chemical nature and composition of the absorbent. As final result, it was established a route based on process efficiency, optimized consumption of energy and absorbent. Thereby, it serves as base for the compact equipment conception to be used in locu into the industry for the removal of hydrocarbon from the natural gas produced