789 resultados para Wear abrasive
Resumo:
This study aimed to evaluate factors associated to orthodontic treatment stability and patient satisfaction in the long-term. A total of 209 patients (88 class I and 121 class II) treated with straight wire fixed appliance were selected at least 5 years post treatment. Six hundred twenty seven dental casts were examined with the PAR Index at pretreatment (T1), end of treatment (T2), and at long-term follow up (T3, mean 8.5 years post treatment). At T3, a Dental Impact on Daily Living questionnaire was used to assess patient satisfaction with the dentition in the long-term. Friedman test and multiple regression analysis were used to evaluate changes among the time points and factors associated with stability and patient satisfaction. Predictive factors used to exam the occlusion were: PAR Index at T1 and T2, age at T1, the amount of time without retainer, length of Hawley retainer wear, length of follow-up, sex, extraction and third molar status. To assess patient satisfaction were considered: changes produced by the orthodontic treatment (PAR T2-T1), post treatment stability (PAR T3), age at the start of treatment (T1), length of treatment (T2-T1), gender, and extraction. Orthodontic treatment produced a significant improvement of 94.2% in the PAR Index (T2-T1), but this change was not associated with the level of satisfaction when the patient was questioned at T3. No significant change was observed between T2 and T3. However, when the sample was divided according to the level of finalization (PAR T2), it was observed that well-finished patients experienced some deterioration (P<.001), whereas the less well-finished ones showed some improvement (P<.05). Even with the deterioration, the well-finished patients still had a better PAR Index at T3 compared to the less well-finished ones (PAR T2- T3). Regression analysis showed that PAR Index at T1 and T2, age at T1, and length of retainer wear had a slight association with occlusal stability (R2 = 0.27). Patient satisfaction was significantly associated only with PAR Index at T3 (r2=0.125, P<.0001). We can conclude that, even thought orthodontic treatment is quite stable, not so well-finished treatments tend to show some improvement and well-finished ones deteriorate some in the long-term. Despite of that, well-finished patients still have better occlusal characteristics. Patient satisfaction is not related to the result of orthodontic treatment; nevertheless, there is a slight association with dentition in the long-term
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The breast cancer is the most incident neoplasia in Brazilian women, configure as important cause of female death in Brazil. Its magnitude is go to be consider as a disease that go out the biological and numerical, extending of the subjective dimension and interrelationships of society and socials experiences, to into in knowledge and practices. Linking of the growing older process, the breast cancer extend as social, economical and cultural dimensions, madding in plot of socials relationships, through that acquire mean. In the context of the high expectative of live and the high number of older age persons, consider that that the high number of years had lived correspond the exposition of this individuals to corporate of the ambientals aggressions and own processes of human constitution of natural wear, like as chronicle-degenerate disease, the example is cancer. In the perspective, we collected narratives of mastectomies women with 60 age or so, about the breast cancer, the body and the growing older process, had has as objectives to reflexes about relatives questions, the comprehension about cancer, like experience, had lived and mean in the context of action and interaction of mastectomies older women, and to comprehend like women interrelationships and respond the changes that grow up of the disease and the growing older process in the everyday of their lives. Through of the narratives. We know that the disease is an initial information that take a form through successives approximation between women with their reality, since the family from hospital institution. The breast cancer to be continue a disease who cause a lot of apprehension and fear, getting and changing the ill s live as marked form. Have dad the body and the growing older process genteels and redimensions by disease, women need to define news and multiples functions due to the contingency that the disease impose
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This research addresses the consumption of women's fashion, through an analysis of the contents of the Estilo magazine. This magazine is an licensing of American Instyle, directed at the female, published by Editora Abril in Brazil since 2002. To guide this research, in relation of the fashionable field, some relevants concepts and authors were worked, like Pierre Bourdieu, Gilda de Souza Melo, Georg Simmel, Gilles Lipovetsky among other fundamental to understanding both the consumption and fashion. Still in search of understanding the discourses that permeated the fashion world were done semi-structured interviews with two costume designers who work in two different shops specializing in fabrics in the Natal's city. Were analyzed Estilo magazines published from June 2008 to June 2009, relating to the data collected in interviews in order to understand how discourses are constructed and disseminated, becoming so efficient in the seduction of women's groups which is directed to achieve and consolidate the production of appropriate and acceptable form to wear
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The current study strives to address the interpersonal relationships of the nursing team from the perspective of the communicative action, by contributing to the health work process. It aims to analyze the interpersonal relationships of the nursing team in its work environment. This is a descriptive study with a qualitative approach. Data collection wal held from interviews, guided by a script with open questions. The study was conducted at a state hospital in the city of Natal/RN/Brazil. The research subjects were the workers of the nursing team, including nurses, nursing technicians and nursing assistants, totaling 16 subjects. The capture of information was performed in April 2012. The project was approved by the Ethics Research Committee, under CEP/UFRN protocol n. º 262/11 and Certificate of Presentation for Ethical Consideration n. º 0289.0.051.000-11. The analysis was performed from the categories that emerged from the research through a dialogue with the authors studied in the theoretical framework of the Theory of communicative action , by Jürgen Habermas, as well as The changing in the world of work, by Ricardo Antunes, and Characterization of the team , by Marina Peduzzi. The outocomes point out that the interpersonal relationship of the nursing team is very troubled, with no interaction among the individuals involved in this process, among themselves and with other health professionals. We have developed a particular concept about team, which is comprised of three essential elements: multiplicity of individuals, common objective and heterogeneity. In the studied environment, it was realized the existence of grouping teams. The interpersonal relationship of the nursing can be a facilitator or an obstacle in the workplace in such a way that causes positive or negative consequences, both to the health workers, and to the sicks. In this context, the interviewees have intensified their viewpoints with regard to the weaknesses that permeate the nursing relationship, by pointing them more frequently than the strengths. The work conditions have signaled a failing situation, which is evidenced by the constant improvisation process before the lack of human and material resources, low wages, deficit in recognizing the nursing worker, and physical and emotional wear, by creating a professional exhaustion. The devaluation of the worker also became a strong factor for this study, because it was characterized a reason of job dissatisfaction, due to the lack of valuation policies, which should be prepared by the institution or, even, they are unknown by the worker itself. The worker participation in the design of these policies has emerged as a relevant factor. The poor work conditions lead the worker to a process of professional demotivation and dissatisfaction, by causing the feeling of devaluation within its work environment. Hence, it was found in this research that the lack of communication leads to situations of inadequate interpersonal relationships, which are creators of an unsuitable environment for the performance of the nursing team
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Venous ulcers (VU) is a chronic injury of the lower extremities and because of its high incidence and recurrence implies long and complex treatments, damaging the quality of life (QOL) and self-esteem (SE) of the people. This study aimed to analyze the association between self-esteem with the quality of life of people with venous ulcers treated in primary care. Cross sectional analytical study with a quantitative approach conducted with 44 people met with VU at 13 primary care units 2 and Mixed units in Natal/RN. The study was approved by the Ethics Committee in Research of the Federal University of Rio Grande do Norte (UFRN), CAAE: 07556312.0.0000.5537. Held data collection from February to April 2014 and used three instruments: a structured form covering sociodemographic, health care and clinical variables, the Rosenberg Self-Esteem Scale and the SF-36. The collected data were entered into a database and processed on computerized software for descriptive and inferential analyzes. The results showed a predominance of people with UV females (65,9%), with more than 60 years (59,1%), married or in a stable relationship (52,3%), low education (86,4%) without occupation (68,2%) and less than one minimum wage income (81,8%). Regarding assistance characteristics was observed that most patients performed the dressing with appropriate material (72,7%), professional or trained caregiver (61,4%) did not use compression therapy (81,8%), treating the injury for more than 6 months (77,3%), lack of guidelines for the use of compression therapy, elevation of legs, and regular exercise (77,3%) and consulting the angiologist last year (52,3% ). Regarding clinical features of the lesion was found that most of the recurrent lesions are (77,3%), over one year of current lesion (52,3%) medium to large lesions (54,8%), without signs of infection (61,3%) and pain (79,5%). The mean SE of respondents was 9,3 (± 5,1). The relations between the SE and the sociodemographic variables, health care and clinics showed that individuals without a partner (a) (p = 0,01), who did not wear compression therapy (p = 0,04), with more 6 months of treatment (p = 0,01) and larger lesions (p = 0,01) had a lower SE. The mean domain and the dimensions of the SF-36 were lower emphasizing the functional capacity 36.5 (± 27,6) and the physical aspects of 15.3 (± 30,6). There were significant correlations between AE people with VU and the domains and dimensions of the SF-36: physical functioning (r = -0,432), general health (r = -0,415), vitality (r = -0,573), aspects social (r = -0,517), mental health (r = -0,612) and mental health dimensions (r = -0,612) and physical health (r = -0,473). Based on these results it is concluded by rejecting the null hypothesis and accept the alternative proposed in the study in which it was found that there is a negative correlation between the SE and the QOL of people with venous ulcers
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The traditional fishing with rafts is characterized by unpredictability, high stakes and inadequate work conditions. The extensive working hours, physical wear, inadequate nutrition, unsanitary conditions, lack of salvage equipment and instruments suitable working, added by the presence of changes in the nutritional status of fisherman, that contribute to the picture of insecurity in high seas, injuries and health. This study aimed to analyze the activity of the fisherman s from Ponta Negra, Natal / RN, and check the conditions of supply of these fishermen and their implications on health and development of their work. To this finality, was used a methodology based on the ergonomic work analysis employing techniques such as observational and interactional conversational action, listening to the answers, observation protocols, photographic and video records. The script conversational dynamic action was developed from literature searches about the artisanal fisheries, culture and food habits of this population, and analyzes the overall situation of focus and two reference situations. To collect data on the usual diet of fisherman as well as quantitative and qualitative analysis that was used for data analysis and 24h recall the Food Frequency Questionnaire (FFQ). The impact of this power to the health of fisherman was evaluated performing a nutritional assessment. The results revealed that the fishermen carry out their activities with poor working conditions, health and nutrition. Feeding practices of these fishermen undertake development work, making it even more stressful, as well contributing to the emergence of Chronic Noncommunicable Diseases. The management of the activity, as well as the current structure of the vessel, also contributes to the adoption of inappropriate feeding practices during the shipment of catch. The results of this indicate the need for adequate interventions in order to assist in recovery and / or maintenance of health of fisherman minimizing reflections of nutritional disorders for the development activity by improving the quality of life in this population
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Electrical Motors transform electrical energy into mechanic energy in a relatively easy way. In some specific applications, there is a need for electrical motors to function with noncontaminated fluids, in high speed systems, under inhospitable conditions, or yet, in local of difficult access and considerable depth. In these cases, the motors with mechanical bearings are not adequate as their wear give rise to maintenance. A possible solution for these problems stems from two different alternatives: motors with magnetic bearings, that increase the length of the machine (not convenient), and the bearingless motors that aggregate compactness. Induction motors have been used more and more in research, as they confer more robustness to bearingless motors compared to other types of machines building with others motors. The research that has already been carried out with bearingless induction motors utilized prototypes that had their structures of stator/rotor modified, that differ most of the times from the conventional induction motors. The goal of this work is to study the viability of the use of conventional induction Motors for the beringless motors applications, pointing out the types of Motors of this category that can be more useful. The study uses the Finite Elements Method (FEM). As a means of validation, a conventional induction motor with squirrel-cage rotor was successfully used for the beringless motor application of the divided winding type, confirming the proposed thesis. The controlling system was implemented in a Digital Signal Processor (DSP)
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Hard metals are the composite developed in 1923 by Karl Schröter, with wide application because high hardness, wear resistance and toughness. It is compound by a brittle phase WC and a ductile phase Co. Mechanical properties of hardmetals are strongly dependent on the microstructure of the WC Co, and additionally affected by the microstructure of WC powders before sintering. An important feature is that the toughness and the hardness increase simultaneously with the refining of WC. Therefore, development of nanostructured WC Co hardmetal has been extensively studied. There are many methods to manufacture WC-Co hard metals, including spraying conversion process, co-precipitation, displacement reaction process, mechanochemical synthesis and high energy ball milling. High energy ball milling is a simple and efficient way of manufacturing the fine powder with nanostructure. In this process, the continuous impacts on the powders promote pronounced changes and the brittle phase is refined until nanometric scale, bring into ductile matrix, and this ductile phase is deformed, re-welded and hardened. The goal of this work was investigate the effects of highenergy milling time in the micro structural changes in the WC-Co particulate composite, particularly in the refinement of the crystallite size and lattice strain. The starting powders were WC (average particle size D50 0.87 μm) supplied by Wolfram, Berglau-u. Hutten - GMBH and Co (average particle size D50 0.93 μm) supplied by H.C.Starck. Mixing 90% WC and 10% Co in planetary ball milling at 2, 10, 20, 50, 70, 100 and 150 hours, BPR 15:1, 400 rpm. The starting powders and the milled particulate composite samples were characterized by X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) to identify phases and morphology. The crystallite size and lattice strain were measured by Rietveld s method. This procedure allowed obtaining more precise information about the influence of each one in the microstructure. The results show that high energy milling is efficient manufacturing process of WC-Co composite, and the milling time have great influence in the microstructure of the final particles, crushing and dispersing the finely WC nanometric order in the Co particles
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Present work proposed to map and features the wear mechanisms of structural polymers of engineering derived of the sliding contact with a metallic cylindrical spindle submitted to eccentricity due to fluctuations in it is mass and geometric centers. For this it was projected and makes an experimental apparatus from balancing machine where the cylindrical counterbody was supported in two bearings and the polymeric coupon was situated in a holder with freedom of displacement along counterbody. Thus, the experimental tests were standardized using two position of the two bearings (Fixed or Free) and seven different positions along the counterbody, that permit print different conditions to the stiffness from system. Others parameters as applied normal load, sliding velocity and distance were fixed. In this investigation it was used as coupon two structural polymers of wide quotidian use, PTFE (polytetrafluroethylene) and PEEK (poly-ether-ether-ketone) and the AISI 4140 alloy steel as counterbody. Polymeric materials were characterized by thermal analysis (thermogravimetric, differential scanning calorimetry and dynamic-mechanical), hardness and rays-X diffractometry. While the metallic material was submitted at hardness, mechanical resistance tests and metallographic analysis. During the tribological tests were recorded the heating response with thermometers, yonder overall velocity vibration (VGV) and the acceleration using accelerometers. After tests the wear surface of the coupons were analyzed using a Scanning Electronic Microscopy (SEM) to morphological analysis and spectroscopy EDS to microanalysis. Moreover the roughness of the counterbody was characterized before and after the tribological tests. It was observed that the tribological response of the polymers were different in function of their distinct molecular structure. It were identified the predominant wear mechanisms in each polymer. The VGV of the PTFE was smaller than PEEK, in the condition of minimum stiffness, in function of the higher loss coefficient of that polymer. Wear rate of the PTFE was more of a magnitude order higher than PEEK. With the results was possible developed a correlation between the wear rate and parameter (E/ρ)1/2 (Young modulus, E, density, ρ), proportional at longitudinal elastic wave velocity in the material.
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The use of polymer based coatings is a promising approach to reduce the corrosion problem in carbon steel pipes used for the transport of oil and gas in the oil industry. However, conventional polymer coatings offer limited properties, which often cannot meet design requirements for this type of application, particularly in regard to use temperature and wear resistance. Polymer nanocomposites are known to exhibit superior properties and, therefore, offer great potential for this type of application. Nevertheless, the degree of enhancement of a particular property is greatly dependent upon the matrix/nanoparticle material system used, the matrix/nanoparticle interfacial bonding and also the state of dispersion of the nanoparticle in the polymer matrix. The objective of the present research is to develop and characterize polymer based nanocomposites to be used as coatings in metallic pipelines for the transportation of oil and natural gas. Epoxy/SiO2 nanocomposites with nanoparticle contents of 2, 4, and 8 wt % were processed using a high-energy mill. Modifications of the SiO2 nanoparticles‟ surfaces with two different silane agents were carried out and their effect on the material properties were investigated. The state of dispersion of the materials processed was studied using Scanning and Transmission Electron Microscopy (SEM and TEM) micrographs. Thermogravimetric analysis (TG) were also conducted to determine the thermal stability of the nanocomposites. In addition, the processed nanocomposites were characterized by dynamic mechanical analysis (DMA) to investigate the effect of nanoparticles content and silane treatment on the viscoelastic properties and on the glass transition temperature. Finally, wear tests of the pin-on-disc type were carried out to determine the effects of the nanoparticles and the silane treatments studied. According to the results, the addition of SiO2 nanoparticles treated with silane increased the thermal stability, the storage modulus and Tg of the epoxy resin and decreased wear rate. This confirms that the interaction between the nanoparticles and the polymer chains plays a critical role on the properties of the nanocomposites
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The present work consists in the analysis of tribologycal properties of basic and multifunctional knitted fabrics. This knowledge has fundamental importance for the textile industry since it can quantify, in an objective way, the tactil. The fabrics used were characterized by friction and mechanical tests for determining the viscoelastic region, wear resistance and friction coefficient of the fabrics used. The stress-strain curve was obtained by the method Kawabata, KES-FB1. Wear tests performed with the aid of equipment Martindale. The measurement of friction coefficient, two methods were used and analyzed comparatively. The first was a method already established worldwide known as KES-FB4 and the second was an innovative method called FRICTORQ, developed by the University of Minho. These two methods were compared taking into account the relative motion between the tribologycal pairs are different from each method. While the first motion is translational, the second is rotational. It was formal that the knitted had a multifunctional fabrics tribologycal performance which was better than the basic knitted fabrics, as the viscoelastic region, was laager highlighting a multifunctional structure, with greater wear resistance mainly on the back side of the knitted fabrics and lower friction coefficient. Performing a comparative analysis between two methods used to measure the friction coefficient, it was formal that both methods were consistent in terms of results. In operational terms, the FRICTORQ showed ease of operation and increased reproducibility of results
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The modern technology of materials and structural integrity of pipelines requests the use of inspection tools named inspection pigs to detect, localize and measure the length, width and depth dimensions of the thickness losses of walls of buried and underwater pipelines in service. These tools run them internally, performing and recording measurements, with performance that varies according to the pig s technology. It has been developed recently an instrumented pig technology, called feller pig. This work aims to indicate factors that influence the feller pig technology performance in the detection and in the accuracy of measurement of the length, width and depth dimensions of the thickness losses on the internal surface of an oil pipeline wall under normal conditions of oil pipe inspection with pig. In this work, is made a collection of factors and an analyses of the technology based on the available literature, as well as an experiment to observe the technology and the factors operating. In the experiment, a feeler pig is used in a pipeline built in carbon steel and in operation that flows petroleum, in witch are observed areas with internal thickness losses occurred naturally. Some of these areas and their dimensions taken by automated ultra-sound scanner are compared with the ones indicated by the feller pig. Based on the data collection, on the analysis and on the experiment, the influence of factors object of this research is discussed. It is concluded that, among these, there are factors related to pipe fabrication tolerances, to wear of pig components, to internal adhesive wear of pipeline, to other pipeline damages and to technology characteristics. Finally, actions are suggested to know better, improve and define the applicability of this technology
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Low cost seals are made of NBR, Nitrile Butadiene Rubber, a family of unsaturated copolymers that is higher resistant to oils the more content of nitrile have in its composition, although lower its flexibility. In Petroleum Engineering, NBR seal wear can cause fluid leakage and environmental damages, promoting an increasing demand for academic knowledge about polymeric materials candidate to seals submitted to sliding contacts to metal surfaces. This investigation aimed to evaluate tribological responses of a commercial NBR, hardness 73 ± 5 Sh A, polytetrafluoroethylene (PTFE), hardness 60 ± 4 HRE and PTFE with graphite, 68 ± 6 HRE. The testings were performed on a sliding tribometer conceived to explore the tribological performance of stationary polymer plane coupons submitted to rotational cylinder contact surface of steel AISI 52100, 20 ± 1 HRC Hardness, under dry and lubricated (oil SAE 15W40) conditions. After screening testings, the normal load, relative velocity and sliding distance were 3.15 N, 0.8 m/s and 3.2 km, respectively. The temperatures were collected over distances of 3.0±0.5 mm and 750±50 mm far from the contact to evaluate the heating in this referential zone due to contact sliding friction by two thermocouples K type. The polymers were characterized through Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC) and Dynamic Mechanical Analysis (DMA). The wear mechanisms of the polymer surfaces were analyzed by Scanning Electron Microscopy (SEM) and EDS (Energy-Dispersive X-ray Spectroscopy). NBR referred to the higher values of heating, suggesting higher sliding friction. PTFE and PTFE with graphite showed lower heating, attributed to the delamination mechanism
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It is analyzed through the concepts of tribology and mechanical contact and damage the suggestion of implementing a backup system for traction and passage of Pipeline Inspection Gauge (Pig) from the inside of pipelines. In order to verify the integrity of the pipelines, it is suggested the possibility of displacement of such equipment by pulling wires with steel wires. The physical and mechanical characteristics of this method were verified by accelerated tests in the laboratory in a tribological pair, wire versus a curve 90. It also considered the main mechanisms of wear of a sliding system with and without lubricant, in the absence and presence of contaminants. To try this, It was constructed a test bench able to reproduce a slip system, work on mode back-and-forth ("reciprocation"). It was used two kinds of wires, a galvanized steel and other stainless steel and the results achieved using the two kinds of steel cables were compared. For result comparative means, it was used steel cables with and without coating of Poly Vinyl Chloride (PVC). The wires and the curves of the products were characterized using metallographic analysis, microhardness Vickers tests, X-ray diffraction (XRD), X-Ray Refraction (XRF) and tensile tests. After the experiments were analyzed some parameters that have been measurable, it demonstrates to the impracticality of this proposed method, since the friction force and the concept of alternating request at the contact between the strands of wire and the inner curves that are part ducts caused severe wear. These types of wear are likely to cause possible failures in future products and cause fluid leaks
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The aim of this study was investigate the consolidation of the biodiesel fuel used in (a) engines of urban and intercity bus companies, (b) a stationary engine. It was necessary to investigate and analyze, technologically, if the biodiesel fuels were presenting troubleshooting relative to wear of parts lied to fuel and to evaluate the consumption fluctuations of this fuel. The urban and intercity bus companies, localized in Natal, Rio Grande do Norte state, Brazil, had 41 and 12 vehicles, respectively. It were analyzed datasheet of each one vehicle during three years, since 2008 until 2010 and were interviewed the management of the maintenance team of bus companies relative to aspects concerning the substitution of the diesel fuel by the B5 biodiesel. The second aim of this study was visually inspect the wear of the parts directly lied to combustion process. For this reason, it was investigated a stationary engine, manufactured by Branco BD5, 5 HP of power, fueled by (a) diesel, (b) biodiesel B5, (c) biodiesel B20 and (d) diesel or biodiesel, both contaminated by distilled water. In this engine, its power utilizing biodiesel B5 versus diesel was lower about 5.2% and, in the investigated case of B20 versus diesel, it was lower around 11.5%