Coating of Cotton Yarn with Poly(vinyl alcohol) and Poly(N-vinyl-2-pyrrolidone) Crosslinked via Ultraviolet Radiation

The coating of cotton fiber is used in the textile industry to increase the mechanical resistance of the yarn and their resistance to vibration, friction, impact, and elongation, which are some of the forces to which the yarn is subjected during the weaving process. The main objective of this study was to investigate the use of synthetic hydrophilic polymers, poly(vinyl alcohol) (PVA), and poly(N-vinyl-2-pyrrolidone) (PVP) to coat 100% cotton textile fiber, with the aim of giving the fiber temporary mechanical resistance. For the fixation of the polymer on the fiber, UV-C radiation was used as the crosslinking process. The influence of the crosslinking process was determined through tensile testing of the coated fibers. The results indicated that UV-C radiation increased the mechanical resistance of the yarn coated with PVP by up to 44% and the yarn coated with PVA by up to 67% compared with the pure cotton yarn, that is, without polymeric coating and crosslinking. This study is of great relevance, and it is important to consider that UV-C radiation dispenses with the use of chemical substances and prevents the generation of toxic waste at the end of the process. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 119: 2560-2567, 2011

Crosslinking of Poly(N-vinyl-2-pyrrolidone) in the Coating of Cotton Yarn

Coating of cotton yarn is employed in the textile industry to increase the mechanical resistance of the yarns and resistance to vibration, friction, impact, and elongation, which are some of the forces to which the yarn is subjected during the weaving process. The main objective of this study is to investigate the usage of a synthetic hydrophilic polymer, poly(N-vinyl-2-pyrrolidone) (PVP), to coat 100% cotton textile yarn, aiming to give the yarn a temporary mechanical resistance. For the improvement of the mechanical resistance of the yarn, the following crosslinking processes of PVP were investigated: UV-C (ultraviolet) radiation, the Fenton and photo-Fenton reactions, and sensitized UV-C radiation. The influence of each crosslinking process was determined through tensile testing of the coated yarns. The results indicated that the best crosslinking process employed was UV-C radiation; increasing the mechanical resistance of the yarn up to 44% if compared with the pure cotton yarn, that is, without polymeric coating and crosslinking. POLYM. ENG. SCI., 51:445-453, 2011. (C) 2010 Society of Plastics Engineers

A surface-enhanced infrared absorption spectroscopic (SEIRAS) study of the oscillatory electro-oxidation of methanol on platinum

The oscillatory electro-oxidation of methanol was studied by means of in situ infrared (IR) spectroscopy in the attenuated total reflection (ATR) configuration using a platinum film on a Si prism as working electrode. The surface-enhanced infrared absorption (SEIRA) effect considerably improves the spectroscopic resolution, allowing at following the coverage of some adsorbing species during the galvanostatic oscillations. Carbon monoxide was the main adsorbed specie observed in the induction period and within the oscillatory regime. The system was investigated at two distinct time-scales and its dynamics characterized accordingly. During the induction period the main transformation observed as the system move through the phase space towards the oscillatory region was the decrease of the coverage of adsorbed carbon, coupled to the increase of the electrode potential. Similar transition characterizes the evolution within the oscillatory region, but at a considerably slower rate. Experiments with higher time resolution revealed that the electrode potential oscillates in-phase with the frequency of the linearly adsorbed CO vibration and that the amount of adsorbed CO oscillates with small amplitude. Adsorbed formate was found to play, if any, a very small role. Results are discussed and compared with other systems. (C) 2010 Elsevier B.V. All rights reserved.

Análise dinâmica de vigas assimétricas em curva com parede fina e aberta submetidas a ação de carga móveis

Fundamentalmente, o presente trabalho faz uma análise elástica linear de pontes ou vigas curvas assimétricas de seção transversal aberta e de parede fina, com propriedades físicas, geométricas e raio de curvatura constantes ao longo do eixo baricêntrico. Para tanto, utilizaram-se as equações diferenciais de VLASOV considerando o acoplamento entre as deformações nas direções vertical, transversal, axial de torcão nal. Na solução do sistema de quatro equações com derivadas parciais foi utilizado um apropriado método numérico de integração (Diferenças Finitas Centrais). A análise divide-se, basicamente, em dois tipos: análise DINÂMICA e ESTATICA. Ambas são utilizadas também na determinação do coeficiente de impacto (C.M.D.). A primeira refere-se tanto na determinação das características dinâmicas básicas (frequências naturais e respectivos modos de vibração), como também na determinação da resposta dinâmica da viga, em tensões e deformações, para cargas móveis arbitrárias. Vigas com qualquer combinação das condições de contorno, incluindo bordos rotulados e engastados nas três direções de flexão e na torção, são consideradas. 0s resultados da análise teórica, obtidos pela aplicação de programas computacionais implementados em microcomputador (análise estática) e no computador B-6700 (análise dinâmica), são comparados tanto com os da bibliografia técnica como também com resultados experimentais, apresentando boa correlação.

Viabilidade tecnica da producao de blocos silico-calcarios na regiao de Santa Maria, no Rio Grande do Sul

Este trabalho é camposto por dois estudos basicamente: um estudo teórico sobre os blocos sílico-calcários de areia-cal e um estudo prático sobre a viabilidade técnica de produção destes blocos em uma região determinada. A pesquisa teórica procurou elucidar o que vem a ser um bloco síilico-calcário, buscando a viabilidade da pesquisa prática e os pontos principais a serem abordados. Foram estudados, nesta parte, as matérias-primas e o processo produtivo empregado na confecção destes elementos, mostrando a importância de cada item para as características do produto final. Foi dada atenção ainda às características técnicas, aos fatores que determinam a produção e emprego e aos aspectos positivos e negativos dos elementos deste tipo produzido em outros locais. A pesquisa prática buscou a disponibilidade de matéria-prima conveniente para a produção de blocos sílicos-calcários, e o efeito das variações do processo produtivo sobre os produtos confeccionados com os materiais estudados. A matéria-prima empregada foi uma areia quartzosa da região de Santa Maria-RS, cal calcítica virgem de São Sepé-RS, e cinza volante da termoelétrica Presidente Médici, em Bagé-RS, fazendo-se variações nas percentagens destes componentes. As variações do processo produtivo foram efetuadas no tipo de moldagem dos corpos de prova, em que foi usada pressão, vibração e vibro-compressão, e na pressão de autoclavagem. Para todas as variações efetuadas foram obtidas as seguintes características: variações por autoclavagem, massa específica aparente, absorção d´água, resistência à compressão, resistência à tração e módulo de elasticidade à compressão, as quais foram relacionadas através de quadros e figuras às diversas variações.

Estudo da efetividade de barreiras de amortecimento no controle de vibrações geradas pelo desmonte com explosivos em mina de carvão à céu aberto

Este trabalho apresenta o estudo da efetividade de barreiras de amortecimento para atenuar a vibração causada pela propagação de ondas sísmicas oriundas de detonações. A barreira consta de uma porção do terreno cujas características de propagação são modificadas artificialmente pela detonação de uma linha de furos com parâmetros idênticos aos dos furos de produção. Os resultados obtidos demonstram a efetividade deste recurso, evidenciado pelo coeficiente de redução entre os valores de vibração gerados em situações com e sem o uso de barreira (0,41) e também através da mudança dos coeficientes da equação de previsão via Distância Escalonada, possibilitando em escala de produção o aumento na carga máxima por tempo de retardo ( 4,9 % à 118,9% ), com redução de custos devido ao menor consumo de retardos por furo ( -5,7 % à - 40,7 % ).

Extração, caracterização estrutural e atividades farmacológicas do olginato obtido da alga marrom Lobophora variegata (Lamouroux) Oliveira Filho, 1977

The alginic acid or alginates are acidic polysaccharides found in brown seaweed widely used in food, cosmetic, medical and pharmaceutical industry. This paper proposes the extraction, chemical characterization and verification of the pharmacological activities of brown seaweed variegata Lobophora . The alginate was extracted from the seaweed Lobophora variegata and part was sulphated for comparative purposes. The native extract showed 42% total sugar, 65% uronic acid, 0,36 % protein and 0% of sulfate, while the sulfate showed 39% , 60%, 0.36% and 27,92 % respectively. The presence of a sulfate group may be observed by the metachromasia with toluidine blue in electrophoresis system and characteristic vibration 1262,34 cm-1 in infrared spectroscopy connections assigned to S = O. We observed the formation of films and beads of native alginate, where more concentrated solution 6% resulted in a thicker and more consistent film. Native alginate showed proliferative activity at concentrations (25 and 50 mcg), (50 mg) and (100 mg) in 3T3 cell line in 24h, 48h and 72h, respectively , as the sulfated (100 mg) in 24 . Also showed antiproliferative or cytotoxic activity in HeLa cells of strain, (25 and 100 mg), (25 and 100 mg) and (25, 50 and 100 mg), to native, now for the sulfate concentrations (100 mg) in 24 (25, 50 and 100 mg) in 48 hours, and (50 and 100 mg ) 72h. For their antioxidant activity, the sulfated alginates have better total antioxidant activity reaching 29 % of the native activity while 7.5 % of activity . For the hydroxyl radical AS showed high inhibition ( between 77-83 % ) in concentrations, but the AN surpassed these numbers in the order of 78-92 % inhibition. The reducing power of AN and AS ranged between 39-82 % . In the method of ferric chelation NA reached 100 % chelating while the AS remained at a plateau oscillating 6.5%. However, in this study , we found alginates with promising pharmacological activities, to use in various industries as an antioxidant / anti-tumor compound

Projeto, construção e análise de um prototipo vibracional em escala de bancada aplicável ao tratamento de água de produção de petróleo bruto, mediante inovadora operação híbrida de adsorção e auto-flotação

A self-flotator vibrational prototype electromechanical drive for treatment of oil and water emulsion or like emulsion is presented and evaluated. Oil production and refining to obtain derivatives is carried out under arrangements technically referred to as on-shore and off-shore, ie, on the continent and in the sea. In Brazil 80 % of the petroleum production is taken at sea and area of deployment and it cost scale are worrisome. It is associated, oily water production on a large scale, carrier 95% of the potential pollutant of activity whose final destination is the environment medium, terrestrial or maritime. Although diversified set of techniques and water treatment systems are in use or research, we propose an innovative system that operates in a sustainable way without chemical additives, for the good of the ecosystem. Labyrinth adsor-bent is used in metal spirals, and laboratory scale flow. Equipment and process patents are claimed. Treatments were performed at different flow rates and bands often monitored with control systems, some built, other bought for this purpose. Measurements of the levels of oil and grease (OGC) of efluents treaty remained within the range of legal framework under test conditions. Adsorbents were weighed before and after treatment for obtaining oil impregna-tion, the performance goal of vibratory action and treatment as a whole. Treatment technolo-gies in course are referenced, to compare performance, qualitatively and quantitatively. The vibration energy consumption is faced with and without conventional flotation and self-flotation. There are good prospects for the proposed, especially in reducing the residence time, by capillary action system. The impregnation dimensionless parameter was created and confronted with consecrated dimensionless parameters, on the vibrational version, such as Weber number and Froude number in quadratic form, referred to as vibrational criticality. Re-sults suggest limits to the vibration intensity

Como se fora brincadeira de roda: a ciranda da ludopoiese para uma educação musical humanescente

The present work concerns an auto-ethnographic study based on life experiences and reflections of an educator at Escola Viva Preschool and Elementary-Middle School, located in the city center of Natal, Rio Grande do Norte. As a cognitive model of operation, we use the metaphor of the Circle Dance. The objective of this study is to identify, interpret and describe the ludopoetics that are achieved through a Musical Education program, which we denominate, Humanescent. The data of this investigation was derived from the music making by Preschool and Elementary-Middle School students at Escola Viva during 2007, 2008 and 2009, from which 20 learners were selected to form the corpus, along with the description and interpretation of photos of their experiences and sand tray scenes. We justify the methodological systemization of the research based on our own pedagogical practice, which supports Musical Education in the schools based on the principals of Embodiment, Autopoesis and Flow. The methodological systemization was developed through an Action Research model and on the concepts of Systemic Development, with the goal of re-reading the context investigated through the structuring of categories of Ludopoesis: Self-esteem, Self-territory, Self-connectivity, Self-realization and Selfworth. We used an observant-participant research approach with regard to the perception of emergent knowledge, the surroundings, the experience lived and the contextual and vibration of the circumstances. Besides this, we used projection to interpret the experiences lived, in the form of drawings, short poems, letters or sand tray scenes as symbolic interpretations of experience. In the unfolding of the Ludopoetic Process (Selfesteem, Self-territory, Self-connectivity, Self-realization and Selfworth) we draw conclusions about the relevance of the ludic musical experience, which foments the formation of the self based on music learning, and which is demonstrated in the Embodiment of the learners. In the auto-formative process (of learners and educators) we observe the importance of pedagogical work based on Musical Humanescent Education that gives value to the music making path to the construction of music and performance in play, creativity, and sensibility. The experience of making music in a playful way allows for organization of the self and its autonomous production in the joy of living within a ludopoetic process. These findings highlight the educator as in a permanent state of selfformation, which generates moments of flow. However, in Musical Humanescent Education, music is learned collectively, doing a circle dance, experiencing love, fostering an expansion of the creative spirit, and giving recognition to playfulness as a necessary condition for education and to the value of music made with the true nature and sensibilities of the educators

Avaliação do módulo de elasticidade da madeira com uso de método não-destrutivo de vibração transversal

Numerosas pesquisas têm estudado os métodos não-destrutivos de avaliação de materiais e sua aplicação àqueles de matrizes complexas, como é o caso da madeira. Um dos primeiros métodos não-destrutivos investigados para aplicação nesses casos foi o da vibração transversal. Apesar de sua concepção simples, e a despeito dos grandes avanços obtidos nessa área com outros métodos, como, por exemplo, o ultra-som, o método de vibração transversal para a determinação do módulo de elasticidade da madeira revela-se como de grande potencial de aplicação, sobretudo pela precisão do modelo matemático a ele associado e pela possibilidade de sua aplicação a peças de dimensões estruturais (in-grade testing). Neste trabalho, apresenta-se o uso desse método na determinação do módulo de elasticidade de três espécies de eucalipto. Foram ensaiados não-destrutivamente e por ensaios mecânicos convencionais de flexão corpos-de-prova de 2 cm x 2 cm x 46 cm de E. grandis, E. saligna e E. citriodora. Os ensaios não-destrutivos foram conduzidos com uso do sistema BING - Beam Identification by Non-destructive Grading, que permite a análise das vibrações do material nos domínios do tempo e da freqüência. Os resultados obtidos revelaram boa correlação entre os dois tipos de ensaios empregados, justificando o início dos ensaios com peças de dimensões estruturais, para a viabilização da técnica nas práticas de classificação estrutural.

Algoritmos genéricos para otimização de uma arquitetura de controle inteligente híerárquico

A hierarchical fuzzy control scheme is applied to improve vibration suppression by using an electro-mechanical system based on the lever principle. The hierarchical intelligent controller consists of a hierarchical fuzzy supervisor, one fuzzy controller and one robust controller. The supervisor combines controllers output signal to generate the control signal that will be applied on the plant. The objective is to improve the performance of the electromechanical system, considering that the supervisor could take advantage of the different techniques based controllers. The robust controller design is based on a linear mathematical model. Genetic algorithms are used on the fuzzy controller and the supervisor tuning, which are based on non-linear mathematical model. In order to attest the efficiency of the hierarchical fuzzy control scheme, digital simulations were employed. Some comparisons involving the optimized hierarchical controller and the non-optimized hierarchical controller will be made to prove the efficiency of the genetic algorithms and the advantages of its use

Controlador preditivo não linear aplicado ao controle de golfadas em processos de produção de petróleo

Slugging is a well-known slugging phenomenon in multiphase flow, which may cause problems such as vibration in pipeline and high liquid level in the separator. It can be classified according to the place of its occurrence. The most severe, known as slugging in the riser, occurs in the vertical pipe which feeds the platform. Also known as severe slugging, it is capable of causing severe pressure fluctuations in the flow of the process, excessive vibration, flooding in separator tanks, limited production, nonscheduled stop of production, among other negative aspects that motivated the production of this work . A feasible solution to deal with this problem would be to design an effective method for the removal or reduction of the system, a controller. According to the literature, a conventional PID controller did not produce good results due to the high degree of nonlinearity of the process, fueling the development of advanced control techniques. Among these, the model predictive controller (MPC), where the control action results from the solution of an optimization problem, it is robust, can incorporate physical and /or security constraints. The objective of this work is to apply a non-conventional non-linear model predictive control technique to severe slugging, where the amount of liquid mass in the riser is controlled by the production valve and, indirectly, the oscillation of flow and pressure is suppressed, while looking for environmental and economic benefits. The proposed strategy is based on the use of the model linear approximations and repeatedly solving of a quadratic optimization problem, providing solutions that improve at each iteration. In the event where the convergence of this algorithm is satisfied, the predicted values of the process variables are the same as to those obtained by the original nonlinear model, ensuring that the constraints are satisfied for them along the prediction horizon. A mathematical model recently published in the literature, capable of representing characteristics of severe slugging in a real oil well, is used both for simulation and for the project of the proposed controller, whose performance is compared to a linear MPC

Desgaste de polímeros estruturais de engenharia em contato de deslizamento com cilindro metálico

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.

Produção de tomate em função da vibração das plantas

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Produção de pimentão com vibração das plantas

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)