Estudo da eficiência de reforços estruturais em vigas de concreto armado com o uso de chapas de aço coladas com resina epóxi: uma análise qualitativa

In civil engineering, a structure is the whole sustainment of a construction and, thus, it is important that it remains intact throughout its lifetime. An engineering construction must last for decades without losing its functionality. However its purpose may be altered and several times the original structure does not meet the new needs of use. Still, in new buildings, the functionality is altered due to possible flaws in execution and the structure, invariably does not reach the desired solicitation needs. In cases like this, the commonly adopted solutions are, basically, the demolishment followed by the reconstruction of the desired mold or the structural reinforcement. This second option, for long years, has not been put to practice due to certain factors such as the high costs for its implantation, use of inadequate reinforcement execution techniques, and the culture of people involved in the area regarding its use and, in this case, the option would always be the reconstruction. Thoughtout the years, some techniques were developed to allow the execution of structural reinforcements with low costs and in efficient ways. An interesting, fast, efficient and economical technique is the structural reinforcement through metal sheets put together with epoxy resin that can be applied in beams, slabs and pillars. In the present work the different behavior of beams reinforced with this technique. Steel is a very recommended material for these reinforcements due to its characteristics related to traction, compression and the effectiveness of the technique related to its cost. For the attachment the epoxy resin is recommended, since it allows the joining of two materials, in this case, steel and concrete. The efficiency of this union is so considerably high that it rarely produces any flaws in adherence and, normally, when it happens it is due to problems in the execution process, not in the union of materials

Avaliação de juntas soldadas em tubos de aço carbono submetidos a altas temperatura e pressões

The welding process in industrial piping is still the most effective way to ensure the durability and quality of the wide range of industrial process, although because of the high demand for energy and quality of the produced products, the piping has been constantly tested for high pressure applications and still high temperature. The welding method analyzed is the TIG (Tungsten Inert Gas) welding or GTAW (Gas-Shielded Tungsten Arc Welding), which ones have as principal feature the utilization of a not consumable tungsten electrode in the torch extremity , in this process is necessary a protective atmosphere of inert gas. The welding TIG advantage is the obtaining of a welded seam clean and with quality for not has slag after the welding. This work has as objective show the variability in the carbon steel piping welding parameters and by the tests in four proof bodies will be shown the influence of the variation of the welding methods in a welded seam. The tests will vary since the piece to be welded preparation, till penetrating liquid tests, welding macrography, welding x-ray and traction tests. Even been a clean and with quality welding is necessary a final inspection in the seam welded looking for defects almost inevitable resulted of the welded process, the obtained results have the objective of indicate and minimize the defects to ensure quality and durability of the welded seam

Análise do comportamento em fadiga de rodas ferroviárias fabricadas pelos processos de forjamento e fundição

Since the beginning of the railway industry until today, rail wheels are important components to the good working of a railway. For being a critical security item, design and maintenance are done with extremely care to avoid failures. Despite de fact of railway components be projected to support a big number of cyclic solicitation during its life, some accidents still occur. These accidents, despite the low frequency, always have great consequences, drawing in great financial, material, and people losses. Nowadays, railway component failure is relatively low, because it’s been projected to work below the materials Fatigue Resistance Limit, however, with the growing demand of faster trains and higher load for each axle, the occurrence probability is even bigger. This work includes a comparative study of two fabrication processes (casting and forging) applied in the production of rail wheels where it was measured the mechanical properties of traction and fatigue. The study also verified through microstructural analysis, hardness, traction and fatigue tests, statistical analysis of fatigue test results and fractographic analysis that forging process lead to better correlations between fatigue life and mechanical properties, providing more security in railroads, less wagon retention caused by corrective maintenance and smaller operational cost with its use

Análise de falhas por fadiga de alto ciclo em eixos de transmissão utilizando o método dos elementos finitos

This work presents a study that aims to validate the fatigue analyses developed on finite element commercial software, ANSYS Workbench. It was based on mechanical tests development of traction and hardness, to verify the mechanical properties of material that the shaft was manufactured (ABNT 1045 steel), it was developed bend test, with purpose to prove the confiability degree of computational analyses, obtaining the maximum stress in a work condition determined with 40 [kgf] of load applied, and at the end, was developed the fatigue test to obtain the number of cycles that the transmission shaft can support in a work condition with 8 [kgf] of load applied. The results obtained during the work present, have to be quite satisfactory with the theoretically expected

Controle de velocidade e tração de rodas independentes para veículos elétricos

This work presents a proposal to replace thetraditional system of traction electric car that usesone electric motor and a mechanical differential, by two electric motors of lower power, controlled byelectronic control low cost. The proposed control isopen loop and uses the technique of Pulse WidthModulation (PWM), discrete and synchronizedaiming to reduce the generation of harmonics. The implementation of two smaller motor one on each wheel-drive distributes the weight of the vehicle, improving the heat exchange of the windings,beyond enable the power components supporting a current of 50% predicted for only one motor . The solution adopted for being open-loop, has a similar behavior to the mechanical differential, where theeffort imposed by the trajectory makes the velocity distribution between the wheels be appropriate tovehicle trajectory

Planejamento do transporte urbano sustentável: uso de bicicletas no município de São Paulo-SP

From its foundation until nowadays, the city of São Paulo has undergone major transformation processes, one of the responsibles for these changes is the presence of efficient transportation ; From construction of roads and routes for the animal traction transportation, railroads, expansion and improvements to the introduction of the automobiles, highways, subway system, among others, all these changes are related to greater flow of people and goods. However nowadays has been reflected issues such as quality of life and development of society in a sustainable way, once we have the construction and reconstruction of space in benefit of capital, and therefore the valuation of individual motorized transport. The overuse of individual motor vehicles are generating an urban chaos, making it increasingly difficult to transit in big cities, the use of bicycles is presented as a viable modal alternative, allowing the flow, and enhancing the health of society and quality of the air

Estudo sobre o funcionamento de sistema de controle de tração em veículos automotores

This study explores the subject of traction control systems through bibliografy review on the spot of Mechanical Engineering. This paper has the objetivo of high light the main components and tecnology involved since MaxTrac system in 1971. It describes systems controled by throttle valve and breaks. Additionally, it i also presented basic knowlodged regarding electronic control unit and wheel sensors

Sistema de gerenciamento de energia para controle de carga/descarga entre baterias de lítio e ultracapacitores, envolvendo sistema de tração elétrica com frenagem regenerativa

Pós-graduação em Engenharia Elétrica - FEIS

Sistema de avaliação e tratamento da coluna lombar com o uso de tração mecânica

Pós-graduação em Engenharia Mecânica - FEG

Técnicas de caracterização microestrutural, por microscopia óptica e microscopia eletrônica de varredura, de aços bifásicos e multifásicos aplicados à indústria automobilística

This project developed microstructural characterization technics of commercial dualphase and multi-phasic (TRIP) steels that were provided by the automotive industry and are currently used as the raw material for the production of automobiles. Inserted in this context, there is the development of the advanced high strength steels in consonance with the ULSABAVC project, which aims the production of safe, economically viable and efficient in terms of fuel consumption vehicles for the 21st century. The micro-structural characterization of biphasic and multiphase steels was done by the identification and quantification of the coexistent phases. In this item, a special attention was given to the technics that were performed using optic microscopy and scanning electron microscopy. An important contribution to this work was the utilization of different alternative chemical reagents (Beraha, Heat-Tinting technics) in addition to the classical ones (Nital and LePera)already used conventionally by the UNESP's Group of Mechanical, Microstructural and Fractografic Characterization of Materials. The revealed microstructures were correlated with the materials' mechanical properties determined through traction tests, such as ultimate tensile strengths, yield strength and stretching important since the material has structural application in the automotive industry. As a result, it was observed the superiority concerning the studied mechanical properties for the biphasic and multiphasic steels when compared to the conventional carbon steels. Besides, it was perceived a large potential for the industrial scale utilization of the Heat Tinting technics in this field, seen its differentiation of the existent phases and easy reproducibility

Alternativa de tratamento simplificado e integrado da retenção intraóssea de incisivo central superior, associada a odontoma: relato de caso

Permanent teeth impaction is highly prevalent among brazilian people. Its etiology is related to local and general factors association. Permanent teeth retention compromises dental occlusion and when anterior teeth are involved, it also brings esthetics impairments which lead to psychological disturbance. Early diagnosis and adequate treatment are extremely important to solve not only occlusal problems but also psychological aspects. Orthodontic traction of impacted teeth can be conducted by using fixed or removable appliances. Although it depends on patient compliance the use of removable appliances provides an anchorage based on the teeth and the palate reducing undesirable side effects. This paper describes the case of a fourteen years old female patient whose right maxillary central incisor was adequately tractioned with a removable orthodontic appliance. Removable orthodontic devices were used at first to reposition teeth in maxillary anterior area what provided adequate space to allow the placement of the impacted incisor and after were also used to traction and position this tooth. The procedure described seemed to be effective, non expensive and a viable treatment to be performed even on the scope of public health services, extending orthodontic treatment to a higher number of patients.

Otimização do tracionamento de canino impactado pela técnica do arco segmentado: relato de caso clinico

Upper canines impaction are considered the second most frequent and are associated to important esthetics and functional limitations. Among the treatment strategies described in the literature the most commonly used are the extraction of the primary canines and the surgical exposure followed by orthodontic traction, that requires an adequate interdisciplinary approach. The aim of this case report is to draw the attention of the clinician to the possibility of adapting the segmented arch technique to manage a canine impaction clinical case.

Tratamento da má oclusão de classe II, divisão 1, na dentadura mista com apareljo extrabucal removivel

Extraoral appliances represent an alternative for correction of Class II malocclusions. The application of external force leads to tooth movement and influence the growth of the maxillomandibular complex. This article aims to present the removable headgear as an adjuvant in the treatment of Class II division 1 in the mixed dentition.

Serological study of brucellosis and leptospirosis in equines of island Maiandeua (Algodoal) state of Para

The aim of this study was to study the seroepidemiological profile of brucellosis and leptospirosis in horses traction Island Maiandeua, state of Para. In two distinct periods, blood samples were collected from 52 animals of both sexes and different ages (2 to 17 years), totaling 104 samples. For the research of antibodies anti-Brucella abortus were used in rapid agglutination test in plate. In the first harvest, none animal was positive, however in the second harvest there were three animals reactive serum. The research of antibodies anti-Leptospira spp. was performed with the use of the microscopic agglutination test (MAT), the first harvest was 23.07% reacting animals and 15.38% at the second harvest, for one or more Leptospira spp. with titers ranging from 100 to 200. The predominant serotype at first and second harvest was the Autumnalis 40% and 37.5% respectively. According to age, it was observed in group 1 (2 to 7 years) 27.78% and 13.89% respectively in the two samples and the second group (> 7 years) was found 12.50% and 18 75% of reactive serum. The results observed in this study demonstrated that the island of Maiandeua, state of Para, there is the presence of Leptospira spp, with the most frequent serovar autumnalis and possible exposure of animals to brucella smooth, suggesting low risk of infection in the population of horses examined.

Effect of crown-to-implant ratio on peri-implant stress: a finite element analysis

The aim of this study was to evaluate stress distribution in the fixation screws and bone tissue around implants in single-implant supported prostheses with crowns of different heights (10,12.5, 15 mm crown-to-implant ratio 1:1, 1.25:1, 1.5:1, respectively). It was designed using three 3-Dmodels. Each model was developed with a mandibular segment of bone block including an internal hexagon implant supporting a screw-retained, single metalceramic crown. The crown height was set at 10, 12.5, and 15 mm with crown-to-implant ratio of 1:1, 1.25:1, 1.5:1, respectively. The applied forces were 200 N (axial) and 100 N (oblique). The increase of crown height showed differences with the oblique load in some situations. By von Mises'criterion, a high stress area was concentrated at the implant/fixation screw and abutment/implant interfaces at crown-to-implant ratio of 1:1, 1.25:1, 1.5:1, respectively. Using the maxiinum principal criteria, the buccal regions showed higher traction stress intensity, whereas the distal regions showed the largest compressive stress in all models. The increase of C/I ratio must be carefully evaluated by the dentist since the increase of this C/I ratio is proportional to the increase of average stress for both screw fixation (C/I 1:1 to 1:1.25 ratio = 30.1% and C/I 1:1 to 1 :1.5 ratio = 46.3%) and bone tissue (C/I 1:1 to 1:1.25 ratio = 30% and C/I 1:1 to 1:1.5 ratio = 51.5%). (C) 2014 Elsevier B.V. All rights reserved.