36 resultados para warp knitted fabric
em Universidade Federal do Rio Grande do Norte(UFRN)
Resumo:
Some fibrous materials, for having properties such as biocompatibility, strength and flexibility, are of great interest for medical and pharmaceutical applications. Among these materials, the fabric made from polylactic acid (PLA) has received special attention, and beside to present these features, is derived from biological source, antimicrobial and bioabsorbable. One of the limitations of PLA is its low wettability and capillarity. Due to this, it is necessary to perform surface modification of the knitted fabric, increasing its hydrophilicity. This work aims to realize the plasma treatment at low pressure in order to increase the surface energy of the polymer. The work was divided into three steps: i) Influence of the gas ratio (oxygen and nitrogen) in the surface modification of PLA fabric after the plasma treatment, ii) physical characterization and physicochemical surface tissue; iii) Evaluation of the effect from current and gas ratio in the capillary rise of tissues and iv) Study of capillarity in yarns and fabrics. The results showed that better gas ratios were the atmospheres: 100% oxygen; 100% nitrogen and 50% oxygen and 50% nitrogen. The surface characterization showed changes in topography and introduction of polar groups which increased the wettability of the fabric. In another part of this study, it was found that the atmosphere containing only nitrogen gas showed the most capillary rise to a current of 0.15 A. The results in capillary yarns and fabrics showed that the thread reached equilibrium in a time much less than the fabric to an atmosphere of 100% nitrogen and 0.15 A. Current Plasma technology was effective to increase the hydrophilicity of PLA fabric, providing surface characteristics favorable for future application in the biomedical field
Resumo:
At a time of changes on the territory during the 19th century, the political and socioeconomic elites of the province and later State of Rio Grande do Norte evolved a discourse in order to justify the permanence of Natal as a city holding a status of capital. In this work we analyze the means employed by the ruling classes to impose their wish to raise Natal to an outstanding position among the existing cities by intervening on the territory during a period of one hundred years (1820-1920). During that time, which was characterized by changing commercial flows and technological development, the elites interventions were essentially directed to the implementation of modes of transportation, especially the railway. We try to understand the reinforcement of Natal as a capital city not only in political and administrative terms, but mainly in a commercial and symbolic manner, through the discourse and interventions undertaken by the local administrative elites, who stimulated the creation of a set of relations on the territory that also imprinted visible marks in the capital s urban fabric. These interventions were based upon the establishment of an infrastructure for exporting the State s production, firstly through and despite the Potengi River, and later on by the construction of railways. Although the project of Natal s hegemony had been outlined before the establishment of the railway network, in both cases the ultimate objective was to reinforce and develop the capital city as a commercial urban center to the detriment of other cities
Resumo:
To Analyze the Managing Plans of Natal in the decades of 1970, 1980 and 1990, identifying elements that had contributed for the growth of the Lagoa Nova quarter, capital one of the Rio Grande do Norte state. Ahead of the sped up growth of the urban centers, many times is not given to analyze which law had taken care of to its objective, and which the imperfections that had appeared during the application of these laws. To make the comparisons in you square them chosen at there distantinct times made possible to analyze the form as the ground of Lagoa Nova absorbed the proposals laws.Therefore toanalyze influences it of the Managing Plans, to make comparatives analyses between the urbanistics condicion, made possible to understand that the fabric urban of the quarter of Lagoa Nova is a true granary of information that it makes possible to the dedicated ones to the urban studies, a true field of analysis
Resumo:
This research presents an outlook of the industries of red ceramic in the region next to the city of Teresina and an analysis of the ceramic products producted in this pole. The microregion investigated possesses 13 boroughs where were identified 32 ceramic in operation, being that 24 are located in Teresina, the ceramic region more important of Piauí, 1 is located in the city of Miguel Leão and 7 is located in Timon city that belongs to the state of Maranhão. The majority of ceramics are pulverized in these two cities, Teresina and Timon , responsible by a largely production independent of distance between fabric and consumer market. Furthermore, there is an artisanal production realized in other boroughs, mainly manual conformation bricks, where are producted diverse types of handicraft and ceramics utilitarian. The objective of this research is to evalue the conformity of ceramic blocks for brick of obstruction made by red ceramic industry of microregion at studying, verifying their pontentialities and adequacy in terms of production. In this research universe made a search of ceramic industries related to the Foundation CEPRO (Foundation Center of Research Social and Economic of Piauí). For the analysis of the ceramic products , were colected 60 crude bricks sample in three industries for their characterization, and 39 burned bricks sample for the Evaluation of Conformity. The results of the characterization made reached a accetptable standard in all formulations and temperature studied. The burned samples were applied to the geometric, physical and mechanical assays according to the ABNT standards (Brazilian Association of Technical Standards). The results of the physical assays showed that all the samples are at the same band recommended by standard. However, through the geometric assays just two industries did not present results according to the standard, due to lack of control in their process such as in their equipments. Taking into account the mechanical properties, only one industry investigated was not according to the standard
Resumo:
The gradual replacement of conventional materials by the ones called composite materials is becoming a concern about the response of these composites against adverse environmental conditions, such as ultraviolet radiation, high temperature and moist. Also the search for new composite using natural fibers or a blend of it with synthetic fibers as reinforcement has been studied. In this sense, this research begins with a thorough study of microstructural characterization of licuri fiber, as a proposal of alternative reinforcement to polymeric composites. Thus, a study about the development of two composite laminates was done. The first one, involving only the fiber of licuri and the second comprising a hybrid composite based of fiber glass E and the fiber of licuri, in order to know the performance of the fiber when of fiber across the hybridization process. The laminates were made in the form of plates using the tereftálica ortho-polyester resin as matrix. The composite laminate made only by licuri fiber had two reinforcing fabric layers of unidirectional licuri and the hybrid composite had two reinforcing layers of unidirectional licuri fabric and three layers of fiber short glass-E mat. Finally, both laminates was exposed to aging acceleration in order to study the influence of environmental degradation involving the mechanical properties and fracture characteristics thereof. Regarding the mechanical properties of composites, these were determined through uniaxial tensile tests, uniaxial compression and three bending points for both laminates in original state, and uniaxial tensile tests and three bending points after accelerated aging. As regards the study of structural degradation due to aging of the laminates, it was carried out based on microscopic analysis and microstructure, as well as measuring weight loss. The characteristics of the fracture was performed by macroscopic and microscopic (optical and SEM) analysis. In general, the laminated composites based on fiber licuri showed some advantages in their responses to environmental aging. These advantages are observed in the behavior related to stiffness as well as the microstructural degradation and photo-oxidation processes. However, the structural integrity of this laminate was more affected in case the action of uniaxial tensile loads, where it was noted a lower rate of withholding his last resistance property
Resumo:
As most current studies, reinforced plastics have been, in recent years, a viable alternative in building structural elements of medium and large, since the lightness accompanied by high performance possible. The design of hybrid polymer composites (combination of different types of reinforcements) may enable structural applications thereof, facing the most severe service conditions. Within this class of composite materials, reinforced the underlying tissues hybrid high performance are taking space when your application requires high load bearing and high rigidity. The objective of this research work is to study the challenges in designing these fabrics bring these materials as to its mechanical characterization and fracture mechanisms involved. Some parameters associated with the process and / or form of hybridization stand out as influential factors in the final performance of the material such as the presence of anisotropy, so the fabric weave, the process of making the same, normative geometry of the specimens, among others. This sense, four laminates were developed based hybrid reinforcement fabrics involving AS4 carbon fiber, kevlar and glass 49-E as the matrix epoxy vinyl ester resin (DERAKANE 411-350). All laminates were formed each with four layers of reinforcements. Depending on the hybrid fabric, all the influencing factors mentioned above have been studied for laminates. All laminates were manufactured industrially used being the lamination process manual (hand-lay-up). All mechanical characterization and study of the mechanism of fracture (fracture mechanics) was developed for laminates subjected to uniaxial tensile test, bending in three and uniaxial compression. The analysis of fracture mechanisms were held involving the macroscopic, optical microscopy and scanning electron microscopy
Resumo:
In this study, it has been investigated the influence of silver film deposition onto 100% polyester woven and non-woven, on the survival of Escherichia coli and Staphylococcus aureus in contact with these surfaces. The treatment was performedin a chamber containing the working gas at low pressure (~ 10-2 mbar). Some process parameters such as as voltage: 470 V; pressure: 10-2 mbar; current : 0.40 A and gas flow: 6 and 10 cm3/min were kept constant. For the treatments with purêargon plasma using a flow of 6 and 10 cm3/min, different treatment times were evaluated, such as, 10 , 20, 30, 40, 50 and 60 minutes. Contact angle (sessile drop), measurements were used to determine the surface tension of the treated fabrics and its influence on the bacteria grow as weel as the possibilities of a biofilm formation. The formation of a silver film, as well as the amount of this element was verified byEDX technique. The topography was observed through scanning electron microscopy (SEM) to determine the size of silver grains formed on the surfaces of the fabric and assess homogeneity of treatment. The X-ray diffraction (XRD) was used to analyze the structure of silver film deposition. The woven fabric treatments enabled the formation of silver particulate films with particle size larger than the non-woven fabrics. With respect to bacterial growth, all fabrics were shown to be bactericidal for Staphylococcus aureus (S. aureus), while for the Escherichia coli (E. coli), the best results were found for the non-woven fabric (TNT) treated with a flow of 10 cm3/min to both bacteria
Resumo:
This study aimed to establish patterns of dynamics of litter and redistribution of rainfall of Caatinga vegetation. Sampling was done monthly for twenty three months in four areas: degraded, successional primary stage, secondary stage and late stage. We installed 72 collectors of 1.0 mx 1.0 m, with nylon fabric background in three areas. Litter deposited was fractionated into leaves, twigs, reproductive structures and miscellaneous, dried and weighed. To assess the stock of accumulated litter we used metal frame with dimensions of 0.5 mx 0.5 m, thrown randomly and collected monthly, taken to the laboratory for oven drying and weighed. To evaluate the decomposition, 40g of litter were placed in nylon bags (litterbags) mesh 1 mm ², dimensions 20.0 x 20.0 cm, being distributed on the soil surface and removed monthly, cleaned, dried and weighed. To evaluate the contribution of rainfall we used interceptometers installed 1.0 m above the ground surface, distributed under the canopy of six species of the caatinga, which evaluated the stemflow through collecting system installed around the stems of these species. The deposition of litter in the primary stage was 2.631,26 kg ha-1; 3.144,89 kg ha-1 in the secondary stage; 3.144,89 kg ha-1 in the late stage. The fraction of leaves was the largest contributor to the formation of litter in three stages. The degraded area showed greater accumulation of litter and decomposition has been sluggish during the dry period. We conclude that occurred greater litterfall in later stages. The late successional stage showed faster decomposition of litter, the evidence that is a better use of litter in nutrient cycling processes and incorporation of organic matter to the soil. The time required to decompose 50 % of the litter in the later stages of succession was lower indicating greater speed of release and reuse of nutrients by the vegetation. The specie jurema preta with less leaf area and consists of leaflets, showed greater internal precipitation in rain events of greater magnitude. The stemflow was not influenced by DAP and basal area. The water lost by trapping represented the largest proportion of total rainfall in all species studied
Resumo:
It historizes and it analyzes the social capital in the area Seridó. The traditions associative seridoenses are reconstructed starting from the dimensions: economical, social, religious person and politics. In them it is possible to notice actions that form the social capital of the area. The country of Seridó present an associative tradition based on the mutual help, in the trust and reciprocity that she remount there are decades in your history. The relationship among the Catholic Church, that historically it is present in the area, and rural communities, through your community associations, it is the backdrop where you/they are the responsible associative elements for the tear of the regional social fabric: in him (the backdrop) he/she is the responsible social capital for the work of the rural community organizations. The Catholic Church, through your social action and the Program of Combat to the Rural Poverty, of Rio Grande do Norte is the league that sustains the actions collective seridoenses
Resumo:
It s in the city spaces, molded from the uses and daily appropriations, that life is woven, as a product of the social relationships from the accumulation of history along with the present day fabric. Within this relationship, the old and the new are elements which make up this tapestry, as a result of the contribution of successive generations. The public square is seen as an example of this relationship, since it consists of a fertile space for opportunities of urban life coexistence. It is within the trace of these considerations that the present study emerges regarding the appropriation and sociability of the Tomé de Sousa Square, located in the city of Salvador, BA, having as its main focus the special relation between the cinema and the public square, as it relates to the space of the exhibition of cinematographic art. The showing of films in public squares makes possible a distinctive means of appropriation which has occurred ever since the beginning of the cinema. Today in Brazil, projects of this nature abound, which aim at presenting the seventh art to a great portion of the population which doesn t have access to conventional movie theater projection rooms. This particular Projeto Cinema na Praça Cinema in the Square Project carried out in Salvador, has become the empirical reference point for such work. This journey reveals the fascination that this great art has woven through time, attracting and charming multitudes. The cinema touches people in a special way, stirring up affectionate feelings, which are reflected in multiple social practices. Regarding this work, what stands out above all are the projections in the squares, initiatives which make it possible for the films to be watched collectively. What was taken into account in order to carry out this work were the reports of those who came regularly to watch the cinema in the Square sessions, those involved with the cinema projects team, and the film makers. To do the work, besides a bibliographical revision, observations were made of participants in the Tomé de Sousa Square, taken from semi-structured interviews with people involved with the film projection projects and those who came regularly to the cinema in the Square sessions. Also investigations were made in newspapers, printed magazines and the internet, from document and iconographic sources. The photographic documentation proved to be an important contribution to the field work. The research therefore develops from the understanding that the social practices are what make possible the uses of and the appropriation of the spaces. Within this perspective the public square emerges as a privileged locus where possibilities flourish for multiple manifestations that social practices can generate
Resumo:
The main objective of the present research is to reflect on the affinities between post-colonial theories - analytical perspectives directed toward the discussion of colonialism and its effects on the contemporary social fabric - and Brazilian educator, Paulo Freire‟s (1921-1997) Pedagogy of the Oppressed, written at the end of the 1960‟s. The study aims to make the argument that the present reflections on the featured work is an example of a post-colonial theoretical framework, delineating a critical modus operandi of colonialism, particularly in its cultural and epistemic dimensions, delineating a problematization of the processes of cognitive domination set, above all, by the European colonization of the Latin American continent, with the formation of the modern-world-system (WALLERSTEIN, 2007), dated from the 16TH Century forward. From this stand point, and especially supported by the contributions of Boaventura de Sousa Santos on the sociology of absence, the present work accentuates Pedagogy of the Oppressed as a set of reflections that bring the possibility of a pedagogy of absence (SANTOS, 1996), having in mind that, this book deals with, the presuppositions of an educational action, which considers the plurality of knowledge and social practices by way of the establishment of a pedagogical practice of collective construction, emancipator and dialogic that arises from the encounter to the indolent reason (SANTOS, 2009) in which the silencing of the voices of the oppressed, construct their conditions of invisibility, promoting also the absence of the social questions inherent to the processes of teaching and learning. It is with this perspective, however, that post colonialism is considered a theoretical site for the affirmation and the reinvention of the Pedagogy of the Oppressed, an obligatory reference in the construction of a prudent knowledge for a decent life (SANTOS, 2006)
Resumo:
This research studies the tradition of epiphany in the community of Cipó de Baixo, which belongs to the city of Pedro II, in the state of Piauí. Readings were made seeeking to emphasize the processivity of the play that navigates between permanence and change. The study starts with a social context of the community, in dialogue with the life history of the owner of the epiphany, Raimundo Milú: strong figure who, along with his family networks, as well as networks of patronage and friendship, struggles for the resistence of the play. The description of the ceremony of Kings, with its constituent parts, punctuates the remarkable character of Cipó community epiphany. This detailed understanding of the play favors the understanding of some of the social vines that serve as the basis for the warp of this cultural practice: modernization vine, where we explore the general motivation of Cipó community epiphany transformations - modernity; family and community exchange vine, which describes the scheme that holds the permanence of the play; masculinity vine, explains the strong gender system that crosses Cipó community epiphany; reinvented tradition vine, where we locate the uniqueness of Cipó community epiphany tradition and its dialogues with modern dynamism; conflict between generation vine, depicts the differences between generations and how they contribute to the dialogue between the traditional and the new; theatrical spectacle vine, describes the play as a performative activity. Thus, we build a social scheme that analyzes the play of Kings of Cipó community as a whole, where change and continuity plan a cultural plot on their own
Resumo:
The present work has the intention to analyze the contribution of the writer and journalist Palmyra Guimarães Wanderley to the education, throughout her writings in the period between 1914 to 1920. I search through her journalist writings produced in the feminine magazine Via Láctea (1914-1915) her idealization, and as in the newspaper A República e Diário de Natal, in the decade of 1920 establishing relationships with education, mostly because of her production in the pages of the paper articles regarding feminine education and women condition. At the same time I sketch the biographic profile of Palmyra Wanderley relating her to the historical moment that she lived. To achieve the proposed goals I begin with a documental research within the available archives and use other sources like pictures and interviews with her relatives. The results of the research show that the worry of Palmira Wanderley with the education in our state, goes beyond her published writings in magazines and newspapers. She has been ahead of Escola de Comércio Feminino and Aliança Feminina, she has also done a conference in the House of the Young Single Ladies' Protection (Casa de Proteção às Moças Solteiras), institution of the Aliança s responsibility that offered shelter, food, formal and religious education to the workers of the Fabric Factory of Natal (Fábrica Tecidos de Natal). Her involvement evidences her contribution to the historiography of the education in Rio Grande do Norte, specially the history of women education ensuring her presence in the day by day history
Resumo:
The use of flexible materials for the development of planar circuits is one of the most desired and studied characteristics, lately, by researchers. This happens because the flexibility of the substrate can provide previously impracticable applications, due to the rigidity of the substrates normally used that makes it difficult to fit into the circuits in irregular surfaces. The constant interest in recent years for more lighter devices, increasingly more compacts, flexible and with low cost, led to a new line of research of great interest from both academic and technological views, that is the study and development of textile substrates that can be applied in the development of planar circuits, for applications in the areas of security, biomedical and telecommunications. This paper proposes the development of planar circuits, such as antennas , frequency selective surfaces (FSS) and planar filters, using textile (cotton ticking, jeans and brim santista) as the dielectric substrate and the Pure Copper Polyester Taffeta Fabric, a textile of pure copper, highly conductive, lightweight and flexible, commercially sold as a conductive material. The electrical characteristics of textiles (electric permittivity and loss tangent) were characterized using the transmission line method (rectangular waveguide) and compared with those found in the literature. The structures were analyzed using commercial software Ansoft Designer and Ansoft HFSS, both from the company Ansys and for comparison we used the Iterative Method of Waves (WCIP). For the purpose of validation were built and measured several prototypes of antennas, planar filters and FSS, being possible to confirm an excellent agreement between simulated and measured results
Resumo:
The world market of Kaolin has been growing as new investments for better quality of materials have been applied. This market produces amounts of dross that are put in the environment in a wrong way, causing damages to it. Trying to reduce these damages, researches have been done in an attempt to use kaolin dross in ceramic. The disposal of kaolin dross in the environment by the industries of the states of Rio Grande do Norte and Paraiba have great impact in society. Usually this dross is disposed clandestinely in places like roads, river banks and lands of small cities. The present work shows the characteristics of the kaolin produced by the mining company in Junco do Seridó, Paraiba state, western Seridó, 300 km from Natal, in the border of both states. After that, researches were done to study its physical and the chemistry characteristics, trying to see if it can be used in white ceramic. The samples got were bolted in fabric of 325# . The technological characteristics tried to use it as a product in white ceramic. For that, it was made a haracterization of the subject matter through enlargement analyses, ATG and ATD, elaborating three formulations that were burned in four different temperatures, 1175, 1200, 1250 and 1300 degrees centigrade up to 30 minutes. After the burning, the subjects were submitted to water absorbing tests, linear retreating, apparent porosity, apparent specific mass, resistance to flexibility and MEV. For one of the mixtures it was obtained demanded properties for a semi porous material