Influência da umidade nas propriedades mecânicas dos compósitos poliméricos híbridos (sisal/ vidro)

This study aims to evaluate the mechanical properties of polymer matrix composites reinforced with sisal fabric bidirectional tissue (Agave sisalana,) and E-glass fibers, containing the following configuration: a polymer matrix hybrid composite (Polyester Resin orthophalic) reinforced with three (3) layers of glass fibers and alternating-2 (two) layers of bidirectional sisal fabric, and finally a composite of polymer matrix reinforced with five (5) layers of glass fiber mat-type E. For this purpose as first step, the preparation of by sisal, since they are not on the market. The composites were made by manual lamination (Hand lay-up) and evaluated for tensile properties and three point bending both in the dry, and wet conditions aswele as immersed in oil. Macroscopic and microscopic characteristics of the materialsweve awalysed, after the completion of the mechanical tests. After the studies, it was proven that the sisal fiber decreases the tensile stiffness of the material above 50% for both situations studied the tensile strength of the material decreases by approximately 40% for the cases mentioned, and when compared to the specific strength stiffness values drop to 14.6% and 29.02% respectively for the dry state only. Constants for bending the values were are to approximately 50% to 25% for strength and stiffness of the material for the cases dry, wet and immersed in oil. Under the influence of tension fluids do not interfere in the stiffness of the material for the bending tests, the same does not occur with the resistance, and these values are modified only in the cases stiffness and flexural strength

Avaliação da estrutura de tecidos técnicos como elemento reforçante em compósitos poliméricos sistema poliéster isoftálico

Materials known as technical textiles can be defined as structures designed and developed to meet specific functional requirements of various industry sectors, which is the case in automotive and aerospace industries, and other specific applications. Therefore, the purpose of this work presents the development and manufacture of polymer composite with isophthalic polyester resin. The reinforcement of the composite structure is a technical textile fabric made from high performance fibers, aramid (Kevlar 49) and glass fiber E. The fabrics are manufactured by the same method, with the aim of improving the tensile strength of the resulting polymer composite material. The fabrics, we developed some low grammage technical textile structures in laboratory scale and differentiated-composition type aramid (100%), hybrid 1 aramid fiber / glass (65/35%) and hybrid 2 aramid fiber / glass (85/15% ) for use as a reinforcing element in composite materials with unsaturated isophthalic polyester matrix. The polymer composites produced were tested in uniaxial tensile fracture surface and it´s evaluated by SEM. The purpose of this work characterize the performance of polymer composites prepared, identifying changes and based on resistance to strain corresponding to the mechanical behavior. The objectives are to verify the capability of using this reinforcement structure, along with the use of high performance fibers and resin in terms of workability and mechanical strength; verify the adherence of the fiber to the matrix and the fracture surface by electron microscopy scanning and determination of tensile strength by tensile test. The results indicate that, in a comparative study to the response of uniaxial tensile test for tensile strength of the composites and the efficiency of the low percentage of reinforcement element, being a technical textile fabric structure that features characteristic of lightness and low weight added in polymer composites

Construção e avaliação térmica de um fogão solar tipo caixa

The present work presents a contribution in the study of modelings of transference of heat for foods submitted to the experimental tests in the considered solar oven, where the best modeling for the beefburger of chicken in study was evaluated, comparing the results, considering this food as a half-infinite(1er object considered model) and,after that, considered the chicken beefburger as a plain plate in transient regimen in two distinct conditions: not considering and another model considering the contribution of the generation term, through the Criterion of Pomerantsev. The Sun, beyond life source, is the origin of all the energy forms that the man comes using during its history and can be the reply for the question of the energy supplying in the future, a time that learns to use to advantage in rational way the light that this star constantly special tax on our planet. Shining more than the 5 billion years, it is calculated that the Sun still in them will privilege for others 6 billion years, or either, it is only in the half of its existence and will launch on the Earth, only in this year, 4000 times more energy that we will consume. Front to this reality, would be irrational not to search, by all means technical possible, to use to advantage this clean, ecological and gratuitous power plant. In this dissertation evaluate the performance of solar cooker of the type box. Laboratory of Solar Energy of the Federal University of the Great River of North - UFRN was constructed by the group (LES) a model of solar stove of the type box and was tested its viability technique, considering modeling foods submitted when baking in the solar oven, the cooker has main characteristic the easiness of manufacture and assembly, the low cost (was used material accessible composition to the low income communities) and simplicity in the mechanism of movement of the archetype for incidence of the direct solar light. They had been proposals modeling for calculations of food the minimum baking time, considering the following models of transference of heat in the transient state: object the halfinfinite, plain plate and the model of the sphere to study the necessary temperature for the it bakes of bread (considering spherical geometry). After evaluate the models of transmission of heat will be foods submitted you the processes of to it bakes of, the times gotten for the modeling with the experimental times of it bakes in the solar oven had been compared, demonstrating the modeling that more good that it portraies the accuracies of the results of the model

Consequências da análise inadequada de um experimento fatorial 2k am parcelas subdivididas e sem replicação

Em experimentos com vários fatores em que alguns são mais difíceis de mudar que outros, pode ser inconveniente executar as provas do experimento em uma forma completamente aleatória, levando o pesquisador a criar naturalmente uma restrição na ordem de execução para poupar tempo ou reduzir os custos. Este tipo de restrição pode resultar em uma generalização do planejamento fatorial, conhecida como experimentos em parcelas subdivididas. Na prática, é comum executar um experimento em parcelas subdivididas e analisá-lo como se fosse completamente aleatorizado. O objetivo principal do trabalho é avaliar o impacto de analisar um experimento com restrição na aleatorização como completamente aleatorizado

Obtenção e aplicação de sistemas microemulsionados na recuperação avançada de petróleo

Due to the need of increasing production in reservoirs that are going through production decline, methods of advanced recovery have frequently been used in the last years, as the use of conventional methods has not been successful in solving the problem of oil drifting. In this work, the efficiency of different microemulsionated systems in the flow of oil from cores from Assu and Botucatu formations. Regarding drifting tests, cores were calcinated at a temperature of 1000°C, for 18 hours, with the aim of eliminating any organic compound present in it, increasing the resultant permeability. Following, the cores were isolated with resin, resulting in test specimens with the following dimensions: 3.8 cm of diameter and 8.7 cm of length. Cores were saturated with brine, composed of aqueous 2 wt % KCl, and oil from Guamaré treatment station (Petrobras/RN). A pressure of 20 psi was used in all tests. After core saturation, brine was injected again, followed by oil at constant flow rate. The system S3 - surfactant (anionic surfactant of short chain), isoamillic alcohol, pine oil, and water - presented the best drift efficiency, 81.18%, while the system S1E commercial surfactant, ethyl alcohol, pine oil, and distilled water presented low drift efficiency, 44,68%

Estudo da água produzida em diferentes zonas de produção de petróleo, utilizando a hidroquímica e a análise estatística de parâmetros químicos

Over exploitation of oil deposits on land onshore or offshore, there is simultaneous generation of waste water, known as produced water, which represents the largest waste stream in the production of crude oil. The relationship between the chemical composition of oil and water production and the conditions in which this process occurs or is favored are still poorly studied. The area chosen for the study has an important oil reserve and an important aquifer saturated with freshwater meteoric. The aim of this work is to study some chemical parameters in water produced for each reservoir zone of production in mature oil fields of Açu Formation, using the hydrochemical and statistical analysis to serve as a reference and be used as tools against the indicator ranges water producers in oil producing wells. Samples were collected from different wells in 6 different areas of production and were measured 50 parameters, which can be classified into three groups: anions, cations and physicochemical properties (considering only the parameters that generated values above detection limits in all samples). Through the characterization hydrochemistry observed an area of water and chlorinated sodium, chlorinated calcium or magnesium (mixed) in well water in different areas of Açu, by applying a statistical treatment, we obtained a discriminant function that distinguishes chemically production areas. Thus, it was possible to calculate the rate of correct classification of the function was 76.3%. To validate this model the accuracy rate was 86%

Uso do pó da palha de carnaúba em compósitos de quitosana

In this work a biodegradable composite using the carnauba straw s powder as reinforcement on chitosan matrix polymeric were manufactured. Firstly, were carried out the chemistry characterization of the carnauba straw s powder before and after treatments with NaOH and hexane. Goering and Van Soest method (1970), flotation test, moisture absorption, FTIR, TG/DTG, DSC and SEM have also being carried out. Composites were developed with variations in granulometry and in powder concentrations. They were characterized by TG/DTG, SEM and mechanicals properties. The results of chemical composition showed that the carnauba straw s powder is composed of 41% of cellulose; 28,9% of hemicellulose and 14% of lignin.The flotation test have indicated that the chemical treatment with NaOH decreased the powder s hidrophilicity.The thermal analysis showed increased of thermal stability of material after treatments. The results of FTIR and SEM revealed the removal of soluble materials from the powder (hemicelluloses and lignin), the material became rougher and clean. The composites obtained showed that the mechanicals properties of the composites were decreased in respect at chitosan films, and the composites with the powder at 150 Mesh showed less variation in the modulus values. The speed test of 10 mm/min showed the better reproducibility of the results and is in agreement to the standard ASTM D638. The SEM analysis of fracture showed the low adhesion between the fiber/matrix. The increase of volume of powder in the composite caused a decrease in values of stress and strain for the samples with untreated powder and treated with hexane. The composite with 50% of the powder s treated in NaOH didn t have significant variation in the values of stress and strain as compared with the composites with 10% of the powder, showing that the increase in the volume of fiber didn t affect the stress and strain of the composite. Thereby, it is concluded that the manufacture of polymeric composites of chitosan using carnauba straw s powder can be done, without need for pre-treatment of reinforcement, become the couple of carnauba straw s powder-chitosan a good alternative for biodegradable composites

Desenvolvimento e teste de um modelo estatístico de identificação das proporções de água produzida em zonas de produção de um campo maduro de petróleo

This study investigates the chemical species produced water from the reservoir areas of oil production in the field of Monte Alegre (onshore production) with a proposal of developing a model applied to the identification of the water produced in different zones or groups of zones.Starting from the concentrations of anions and cátions from water produced as input parameters in Linear Discriminate Analysis, it was possible to estimate and compare the model predictions respecting the particularities of their methods in order to ascertain which one would be most appropriate. The methods Resubstitution, Holdout Method and Lachenbruch were used for adjustment and general evaluation of the built models. Of the estimated models for Wells producing water for a single production area, the most suitable method was the "Holdout Method and had a hit rate of 90%. Discriminant functions (CV1, CV2 and CV3) estimated in this model were used to modeling new functions for samples ofartificial mixtures of produced water (producedin our laboratory) and samples of mixtures actualproduced water (water collected inwellsproducingmore thanonezone).The experiment with these mixtures was carried out according to a schedule experimental mixtures simplex type-centroid also was simulated in which the presence of water from steam injectionin these tanks fora part of amostras. Using graphs of two and three dimensions was possible to estimate the proportion of water in the production area

Serviço Social e terceiro setor: considerações sobre as atuais relações e condições de trabalho para o Assistente Social em Natal

The present study analyses the actual relations and work conditions found in the third sector in Natal city, in the context of productive restoration and increasingly retraction from the State in providing Social Service before the new approach that has been destined to the social issue. The study talks about the work of the social worker when fighting the different expressions the social issue has, such as social service provision as a way of teamwork associated to work relations and conditions, to accessible resources and quality control management. These are elements that affect and interfere in the accomplishment and in the work of the social worker itself. The State s improvement, according to neoliberal-political precepts and increasingly retraction from the public investment in the areas of social concern (health, social welfare, assistance) and in the wage and employment policy, besides expanding the partnership with the public and private areas, in search for social services with quality, it has diversified the structures of the professional work with the growth of the so called third sector institutions. However, the absorption of the social workers by the third sector groups in general, has as major features the impoverishment of work relations, the maintenance of an unequal salary model, pointing out the deadline contracts and/or single tasks that generate work instability. The research debates, with a critical view and full perspective, over the conception of the third sector, interpreted as an action that expresses functions and values, treated as a real phenomenon generated from the restoration of the capital based on neoliberal principles. This study aims for responding what the established work relations are and under what work conditions the social worker has been fitting in the third sector and how such a reality echoes in the current work conditions for a social work in the city of Natal, before this new model of state intervention that transfers part of the social service provision to distinctive divisions of society, among them the so called third sector. The research results have shown that like the other workers the social worker passes through the same crises, dilemmas, advances and challenges that occur in the world of employment and which are expressed in the drop of salary average in the growth of contemporary contracts, unemployment, and in the ever more selective requirements to one be included in the social spaces, where the professional work is done, having as a result a greater impoverishment of work relations and conditions as well as more vulnerability as a salaried occupation

Famílias privadas de liberdade: a saga da violência vivenciada por adolescentes que trilham os áridos caminhos da criminalidade

This paper has as its main focus the relation between the infringement act and the adolescents families social economical problematic, who obey the social educational deprivation of freedom at CEDUC in the district of Pitimbu RN, establishing in the theme Children and Adolescents, with the objective of showing how these families breed in the social economical and cultural political aspect. It also seizes who those adolescents are and their family members in their social aspect and as those families face their daily activities. The focus on the social matter, family, adolescent, infringement act, exclusion, inclusion formed the analysis categories which made myths and reality possible, taking into consideration the infringement act in our society. The data collection showed that those families conditions of life are of poverty. Families originated from low social classes, 62.5 % coming from the countryside and living with a daily income ranging from R$ 0,31 to R$ 8,31. Their level of education is low; there is lack of human and citizenship rights and no professional qualification whatsoever. It questions the degrading social exclusion suffered by millions of Brazilian people due to social, political and infringement economical problems. Has this favored the infringement practice? How to confirm the families lack of competence having the social vulnerability? Are the Public Political Institutions really performing the way they should? Are they really carrying out their role as they should? We have noticed that from then on, the necessity of understanding the exclusion/inclusion suffered not only in an imprecise and empty way, but understood as processes of integrative exclusion or ways of delinquency, where the excluding is not only the only one who has lack of material care but the one who is seen or recognized as a person, is not being treated as one. The effort of this paper provided an approach to our object, and the seizing of a close relation between the infringement act and the exclusion process or inclusion suffered, which are submitted to families of those adolescents who deprive of freedom

Desafios e limites da prática política do sindicalismo rural: um estudo de caso em São Paulo do Potengi/RN

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Saúde do trabalhador: entre os dispositivos legais e as práticas efetivas

The health worker is seized in this research beyond the mere applicability of legal devices concerning the legislation of Labor, in order to be established correlations with activities alluding to the public power in the ambit of State of Rio Grande do Norte (RN). This dissertation is an cutting of analysis circumscribed in the research, "Accidents at work: law, citizenship and justice," of the Grupo de Estudos Seguridade Social e Trabalho (GESTO) of Universidade Federal do Rio Grande do Norte (UFRN). The overall goal turned to apprehend and relate contradictory elements inherent compliance of Occupational Health and Safety (OHS) in the supermarket which showed the highest occurrence of legal violations recognized by the Labor Justice of RN in the period between 2006 and 2008 . The specific objectives turned to identify, from the condemnatory sentences, violations inherent in the protective direction of the OH & S legislation; analyze the relationship of health damages to workers at the supposed recognition of rights claimed in condemnatory sentences and correlate violations inherent in the legislation OSH impacts on the health of workers, from data contained in expert reports. The justification for perform the research backed up, among other factors, in the fact that class of activity has been presented as the most recurrent in condemnatory sentences, since it chose to focus the analysis on documentary evidence from the supermarket which showed greater expression in relation to violations of the OSH legislation. From a qualitative perspective, the methodological approach was based on content analysis of thirteen condemnatory sentences, handed down by the potiguar labor justice, and three expert reports from a large supermarket in the city of Natal/RN. Aftermaths are evidenced relating to the cyclical processes of reorganization of capital, demanding requirements for labor organizations whose strategies for survival include identifying mechanisms to extract as much of the work force. Structural determination and ideological context that puts into question the historical achievements of workers, for example the legal devices aimed at preventing workplace accidents, expressed in this research as relativized, showing limitations of reach, as was inferred the indemnities, by material and moral damages, arising from Work-Related Musculoskeletal Diseases (MSDs'S), recognized by the laborite judiciary

As Mulheres e as Muralhas do Patriarcado e do Capitalismo: Terceirização e Precarização do Trabalho no Sistema do Capital

Our dissertation deals with the material living conditions of women workers and the relations of the wage who undergo in the hospital scope, taking as the locus of empirical research the Hospital Dr. João Machado, located in Natal / RN. Its purpose is to analyze the main implications of precarious work contracts in the economic and social dimensions from life of workers, explaining the main conditionings. The majority presence of women in wage relations not only in the hospital service, as well as in the service sector in general has motivated us to appreciation of the form of participation of women in health services and, in particular, at the hospital space. From the critical dialectical method, through processes of successive approximations to the reality, we analyze the patriarchal system of social relations and their repercussions for the Social and Sexual Division of Labor in the context of contemporary capitalist society, explaining the determinants of inequality, founded in social relations of sex, to the predominance of women in the hospital service and unveiling these participation trends in the labor market. The analyzes are based on bibliographic research - theoretical and methodological basis of research - combined with reflections that emerged from the field. The systematized and analyzed information reveal the uniqueness of the current social and economic situation of workers women with ties outsourced, paradoxically expresses on the expansion of the insertion in universe of labor, in overexploitation, in the precariousness of work and living conditions and persistent inequality in and in the social relations and in relations between the sexes

O elo entre o serviço social e o judiciário: demandas, desafios e contribuições na defesa de Direitos

Unveiling the link between the Social Services and the Judiciary is the object of this work, since the judiciary is constituted as one of the socio-occupational areas of the profession in the sphere of the state, seize the demands placed on professionals which work becomes relevant , considering that these are embody the multiple expressions of social issues, constituting a challenge to social work, while influencing the contributions that the profession has engendered in the defense and expansion rights. It constitutes an analysis from the standpoint of theoretical and methodological basis Qualiquantitative taking for granted the rights violations against children and adolescents in their social, legal and historical guide to the topic. For this we used a theoretical Marxist Behring (2009), Colman (2008), Faleiros (2205), Faria (1999, 2001), Fávaro (2007, 2008), Iamamoto (1985, 1992, 2002, 2006, 2007) Yazbek, Marx (1983), Netto (1994), Nicholas (1984), Pequeno (2009), Rizinni (1997, 2008), Santos (2009), Sales (2006), Telles (1999), Tonet (2009), among others. Besides literature, empirical research conducted through semi-structured interviews using a script and written records and systematic observation / free during interviews. The subjects were 06 social workers from the area of the judiciary to act on Justice for Children and Youth, Family Court and NOADE in Natal / RN. The research aims to analyze the demands and challenges of Social Services and their contribution in ensuring and enforcing rights in courts nowadays. The route established between knowledge and method involves conceptual analysis on the Judiciary, Social Services, and Child and Adolescent Rights. Seize-up in this study the existing contradictions in confronting the multiple expressions of social issues in the context of the judiciary. The research allowed us to identify relevant aspects regarding the challenges and demands placed Social Service; limits on defense and expansion of their rights and contradictions within sociojurídico. For being one of the judiciary institutions that comprise the system warranty rights, social workers also face difficulties in implementing the professional doing since the ills posed by current sociability capital focus in everyday spaces socio-occupational presented here. On the other hand, is commendable acting those protagonists who believe, defend and contribute to the defense and expansion rights

Desafios e limites da prática do sindicalismo rural :um estudo de caso em São Paulo do Potengi/RN

The dissertation analyzes how the syndical practice of the workers rural Brazilians works your aspects of mobilization and claim in front of the execution of attendance services and providences, instituted in the marks of the military dictatorship, in the decade of 1970. We try to apprehend how these services have been interfering in the development of base works. Considering base works, as an enduring political formation of the rural workers, formation of new syndical leaderships and an effect participation of the workers in the political spaces. We trace the path of the rural workers' organization, starting from the previous period to the military stroke of 1964, while protagonists inserted in the national political conjuncture, organizing fight fronts and conquering rights. The research reveals that the rural workers' syndical movement, when it develops the activities coming from Funrural, established in 1971, they confront a dilemma that go through the political nature of your practice, which such activities can reduce the syndical rural workers, to a antity of assistance, and so interfere in the accomplishment of base works with the rural working class. The rural workers' syndical movement, inserted in the several conjunctures, since of your emersion in ante-64, when they have passed by growth and retrocession, they built along this period a structure to the national level, which makes possible the recognition of the rural workers' organization, as a class, and human being politicians of your own structure. It is in this context that the syndical practice is analyzed, emphasizing your limits and your possibilities while policy strenght nationally constituted