Efeito da introdução de resíduo de cinza de forno cerâmico em massa para cerâmica estrutural

The red ceramics and structural ceramics, as they are known, include ceramic materials made by blocks of seals and structures, bricks, tiles, smail flagstones manacles, rustic floors and ornamental materials. Their fabrication uses raw material such as clay and clay sites, with some content of impurity. It has good durability and mechanical strength to compression, low cost, making it one of the mainly used materials in civil engineering. The incorporation of many industrial activities residue to ceramic products is a technological alternative for reducing the environmental impact caused by its carefree disposal. This incorporation can promote chemical change and inertness of metals from residue, by fixation in the glassy phase of ceramic during the burning stage. The main aim of this project is to study the technical feasibility of the addition of ceramic oven ash into formulations of mass for structural ceramics. In this project two kinds of clay (plastic and non-plastic) were used, as well as the ash from firewood used in the process of burning of structural ceramics. A group of experiments was outlined, which permitted the evaluation of the influence of the burning cycle in different temperatures of the ash content in formulations for ceramic blocks through technological properties, mechanical behavior and microstructure. Five samples were processed of each one of the masses of plastic and non-plastic clay without addition of ash and with addition of ash on the percentages of 10 % and 20 %, for temperatures of 850 °C, 950 °C, 1050 °C and 1150 °C, obtained through sinterization process. Among the studied compositions, the one which presented best performance was the mass of clay with 10 % of ash, at temperature of 1150 °C, with the smallest absorption of water, the smallest apparent porosity, specific apparent mass a bit over the others and greatest mechanical resistance to flexion. The composition made confirmed the technical feasibility of the use of ash in the mass for structural ceramics with maintenance of its necessary characteristics for its purposes

Adaptação eletrônica de um leitor mecânico de coto, investigação e desenvolvimento de interface CAD

Due to advances in the manufacturing process of orthopedic prostheses, the need for better quality shape reading techniques (i.e. with less uncertainty) of the residual limb of amputees became a challenge. To overcome these problems means to be able in obtaining accurate geometry information of the limb and, consequently, better manufacturing processes of both transfemural and transtibial prosthetic sockets. The key point for this task is to customize these readings trying to be as faithful as possible to the real profile of each patient. Within this context, firstly two prototype versions (α and β) of a 3D mechanical scanner for reading residual limbs shape based on reverse engineering techniques were designed. Prototype β is an improved version of prototype α, despite remaining working in analogical mode. Both prototypes are capable of producing a CAD representation of the limb via appropriated graphical sheets and were conceived to work purely by mechanical means. The first results were encouraging as they were able to achieve a great decrease concerning the degree of uncertainty of measurements when compared to traditional methods that are very inaccurate and outdated. For instance, it's not unusual to see these archaic methods in action by making use of ordinary home kind measure-tapes for exploring the limb's shape. Although prototype β improved the readings, it still required someone to input the plotted points (i.e. those marked in disk shape graphical sheets) to an academic CAD software called OrtoCAD. This task is performed by manual typing which is time consuming and carries very limited reliability. Furthermore, the number of coordinates obtained from the purely mechanical system is limited to sub-divisions of the graphical sheet (it records a point every 10 degrees with a resolution of one millimeter). These drawbacks were overcome by designing the second release of prototype β in which it was developed an electronic variation of the reading table components now capable of performing an automatic reading (i.e. no human intervention in digital mode). An interface software (i.e. drive) was built to facilitate data transfer. Much better results were obtained meaning less degree of uncertainty (it records a point every 2 degrees with a resolution of 1/10 mm). Additionally, it was proposed an algorithm to convert the CAD geometry, used by OrtoCAD, to an appropriate format and enabling the use of rapid prototyping equipment aiming future automation of the manufacturing process of prosthetic sockets.

Eletrofiação e caracterização de membranas biopoliméricas a base de quitosana extraídas dos exoesqueletos de crustáceos

Chitin and chitosan are nontoxic, biodegradable and biocompatible polymers produced by renewable natural sources with applications in diverse areas such as: agriculture, textile, pharmaceutical, cosmetics and biomaterials, such as gels, films and other polymeric membranes. Both have attracted greater interest of scientists and researchers as functional polymeric materials. In this context, the objective of this study was to take advantage of the waste of shrimp (Litopenaeus vannamei and Aristeus antennatus) and crabs (Ucides cordatus) from fairs, beach huts and restaurant in Natal/RN for the extraction of chitin and chitosan for the production of membranes by electrospinning process. The extraction was made through demineralization, deproteinization, deodorization and deacetylation. Morphological analyzes (SEM and XRD), Thermal analysis (TG and DTG), Spectroscopy in the Region of the Infrared with Transformed of Fourier (FTIR) analysis Calorimetry Differential Scanning (DSC) and mechanical tests for traction were performed. In (XRD) the semicrystalline structure of chitosan can be verified while the chitin had higher crystallinity. In the thermal analysis showed a dehydration process followed by decomposition, with similar behavior of carbonized material. Chitosan showed temperature of maximum degradation lower than chitin. In the analysis by Differential Scanning Calorimetry (DSC) the curves were coherent to the thermal events of the chitosan membranes. The results obtained with (DD) for chitosan extracted from Litopenaeus vannamei and Aristeus antennatus shrimp were (80.36 and 71.00%) and Ucides cordatus crabs was 74.65%. It can be observed that, with 70:30 solutions (v/v) (TFA/DCM), 60 and 90% CH3COOH, occurred better facilitate the formation of membranes, while 100:00 (v/v) (TFA/DCM) had formation of agglomerates. In relation to the monofilaments diameters of the chitosan membranes, it was noted that the capillary-collector distance of 10 cm and tensions of 25 and 30 kV contributed to the reduction of the diameters of membranes. It was found that the Young s modulus decreases with increasing concentration of chitosan in the membranes. 90% CH3COOH contributed to the increase in the deformation resulting in more flexible material. The membranes with 5% chitosan 70:30 (v/v) (TFA/DCM) had higher tensile strength

Feeding substrates to black coconut bunch weevil, Homalinotus coriaceus (Gyllenhal) (Coleoptera: Curculionidae), rearing in laboratory

A broca do cacho do coqueiro, Homalinotus coriaceus (Gyllenhal), é uma praga limitante da produção de coco no Brasil, sendo que tanto as larvas como os adultos provocam a queda das flores femininas e dos frutos imaturos, pela interceptação do fluxo de seiva ou pela alimentação direta nas estruturas reprodutivas. em virtude da escassez de informações sobre sua biologia, realizou-se esse trabalho com o objetivo de desenvolver uma metodologia mais adequada para a criação da praga em laboratório. Foram utilizados os parâmetros biológicos para avaliação e comparação dos sistemas de criação estudados.Toletes de cana-de-açúcar foram utilizados como substrato para alimentação dos adultos coletados no campo e obtenção dos ovos. As larvas foram criadas em três substratos alimentares no Laboratório de Entomologia da Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA)-CPATC (Centro de Pesquisa Agropecuária dos Tabuleiros Costeiros), em Aracaju, SE. Os substratos alimentares estudados foram: o mesocarpo do coco, dieta para criação da broca dos citros e dieta para criação da broca do olho do coqueiro, sendo esta a que proporcionou o melhor desenvolvimento larval num menor tempo, com boa viabilidade, maior facilidade no preparo e manutenção.

Estudo da flamabilidade e resistência à chama de compósito de poliéster insaturado e fibra da folha do abacaxizeiro (PALF)

In the present research work, composites were prepared using pine apple leaf fibres (PALF) as reinforcement with unsaturated polyester resin as matrix, incorporating with fire retardant at different compositions. The PALF was obtained from the decortication of pine apple leaves obtained from Ramada 4 from Ielmo Marinho in the State of Rio Grande do Norte. The unsaturated polyester resin and the catalyzer were bought from the local establishment. The fire retardant, aluminium tri-hydroxide - Al(OH)3 was donated by Alcoa Alumínio S.A and was used in the proportions of 20%, 40% and 60% w/w. Initially the fibres were treated with 2% NaOH for 1 hour, to remove any impurities present on the fibre surface, such as wax, fat, pectin and pectate, in order to have a better adsorption of the fibres with the matrix as well as the flame retardant. The fibre mat was prepared in a mat preparator by immersion, developed in the Textile Engineering Laboratory, at the UFRN. The composites (300x300x3 mm) were prepared by compression molding and the samples (150x25x3 mm) for analysis of the properties were cut randomly using a laser cutter. Some of the cut samples were used to measure the smoke emission and fire resistance using UL94 standard. Mechanical tension-extension and flexural properties were carried in CTGás RN and the Laboratório de Metais e Ensaios Mecânicos Engenharia de Materiais UFRN , as well as SEM studies were carried out at Núcleo de Estudos em Petróleo e Gás Natural - UFRN . From the observed results, it was noted that, there was no marked influence of the fire retardant on the mechanical properties. Also in the water absorption test, the quantity of water absorbed was less in the sample with higher concentration of fire retardant. It was also observed that the increase in the proportion of the fire retardant increased the time of burning, may be due to the compactness of the composite due to the presence of fire retardant as a filling material even though it was meant to reduce the rate of inflammability of the composite

Influência da corrente de pulso, do tempo de pulso e diâmetro de gota sobre a estabilidade da transferência metálica no processo MIG-P

To obtain a process stability and a quality weld bead it is necessary an adequate parameters set: base current and time, pulse current and pulse time, because these influence the mode of metal transfer and the weld quality in the MIG-P, sometimes requiring special sources with synergistic modes with external control for this stability. This work aims to analyze and compare the effects of pulse parameters and droplet size in arc stability in MIG-P, four packets of pulse parameters were analysed: Ip = 160 A, tp = 5.7 ms; Ip = 300 A and tp = 2 ms, Ip = 350 A, tp = 1.2 ms and Ip = 350 A, tp = 0.8 ms. Each was analyzed with three different drop diameters: drop with the same diameter of the wire electrode; droplet diameter larger drop smaller than the diameter of the wire electrode. For purposes of comparison the same was determined relation between the average current and welding speed was determined generating a constant (Im / Vs = K) for all parameters. Welding in flat plate by simple deposition for the MIG-P with a distance beak contact number (DBCP) constant was perfomed subsequently making up welding in flat plate by simple deposition with an inclination of 10 degrees to vary the DBCP, where by assessment on how the MIG-P behaved in such a situation was possible, in addition to evaluating the MIG-P with adaptive control, in order to maintain a constant arc stability. Also high speed recording synchronized with acquiring current x voltage (oscillogram) was executed for better interpretation of the transfer mechanism and better evaluation in regard to the study of the stability of the process. It is concluded that parameters 3 and 4 exhibited greater versatility; diameters drop equal to or slightly less than the diameter of the wire exhibited better stability due to their higher frequency of detachment, and the detachment of the drop base does not harm the maintenance the height of the arc

Desenvolvimento de perfis aerodinâmicos a partir de suas características utilizando redes neurais artificiais

One of the current major concerns in engineering is the development of aircrafts that have low power consumption and high performance. So, airfoils that have a high value of Lift Coefficient and a low value for the Drag Coefficient, generating a High-Efficiency airfoil are studied and designed. When the value of the Efficiency increases, the aircraft s fuel consumption decreases, thus improving its performance. Therefore, this work aims to develop a tool for designing of airfoils from desired characteristics, as Lift and Drag coefficients and the maximum Efficiency, using an algorithm based on an Artificial Neural Network (ANN). For this, it was initially collected an aerodynamic characteristics database, with a total of 300 airfoils, from the software XFoil. Then, through the software MATLAB, several network architectures were trained, between modular and hierarchical, using the Back-propagation algorithm and the Momentum rule. For data analysis, was used the technique of cross- validation, evaluating the network that has the lowest value of Root Mean Square (RMS). In this case, the best result was obtained for a hierarchical architecture with two modules and one layer of hidden neurons. The airfoils developed for that network, in the regions of lower RMS, were compared with the same airfoils imported into the software XFoil

Perfis de distribuição volumétrica de pontas XR 11003 e TXVK-4 em diferentes condições de pulverização

Com o objetivo de avaliar a uniformidade da distribuição volumétrica e o efeito da angulação dos bicos na barra em pulverizações, foi conduzido experimento em laboratório, com dez unidades de cada uma das pontas de jato plano XR 11003 e de jato cônico vazio TXVK-4, fabricadas pela Spraying Systems Co. As pontas XR 11003 foram avaliadas, isoladamente, em mesa de prova para bicos construída conforme a Norma ISO 5682-1:1996, a 0,30; 0,40 e 0,50 m de altura, submetidas à pressão de 200 e 300 kPa e posicionadas com ângulos de 30º e 45º no sentido horário e anti-horário e na vertical; as pontas TXVK-4 foram avaliadas nas mesmas alturas, porém a 300 e 400 kPa, e somente na vertical. A distribuição média do volume coletado em cada configuração, das dez unidades de cada ponta, foi inserida num programa computacional, desenvolvido para o estudo, que permitiu a simulação do padrão de deposição de uma barra pulverizadora, com 24 bicos, com sobreposições variáveis, obtendo-se, ao final, o coeficiente de variação da sobreposição, o desvio- padrão e a média do volume aplicado. Os resultados sugerem a necessidade de ajustes no espaçamento entre bicos para a obtenção de melhor uniformidade na distribuição, principalmente quando se utiliza ângulo na barra; há menor influência da variação da altura da barra sobre a uniformidade da distribuição quando o espaçamento entre bicos é reduzido.

Viabilidade do uso de secadores solar de convecção natural e forçada para a secagem do coco Licuri

Licuri is a palm tree from the semiarid regions of Bahia State, Brazil. It is an important source of food and feed in that region, since their nuts are commonly eaten by humans and used as maize substitute for poultry feeding. The aim of this dissertation is to study the feasibility for use of natural convection solar dryers and forced being compared with the traditional drying outdoors for drying coconut licuri Syagrus coronate. The study led to the construction of two prototype solar dryer for carrying out experiments proving: model Solar Drying System Direct Exposure to Natural Convection built with wood, has a drying chamber with direct cover transparent glass laminates 4 mm, using techniques for proper isolation of the drying chamber. The two prototypes were comparatively analyzed for performance and drying efficiency with traditional extractive use by the community. Were evaluated the variables: time and drying rates and quality of the final samples of coconut licuri. The fruits were harvested and brought the town of Ouricuri, in the city of Caldeirão Grande, BA for the experiments comparing the three methods of drying was used a standard load of 4.0 kg The quantitative analysis for the result of the drying rate was found in 74% yield and 44% for natural and forced convection respectively compared with the traditional drying. These drying rates represent variation 3-5 times lower. Drying using forced convection licuri showed better quality, was found in a reddish pulp, representing the quantities that were kept of the nutrient beta carotene, and not notice the flavor change from the previous system, the final cost of construction of this system were higher . The prototypes built competitive advantage and had testified fully to resolve the technical difficulties previously encountered in the production of products made of coconut licuri. Allowing add value and increase their potential use for the fruit extractive communities of semi-arid region of Bahia

Modificação superficial do tecido de malha de ácido polilatico (PLA) por tratamento plasma

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

Beneficiamento de sementes de café e efeitos na qualidade física

A pesquisa foi realizada com o objetivo de verificar a possibilidade de uso da máquina de pré-limpeza, da máquina de limpeza e classificação (ventiladores e peneiras) e da mesa densimétrica para o beneficiamento de sementes de café e, paralelamente, avaliar seus efeitos na qualidade física do lote. Para essa finalidade, um lote de sementes de café arábica 'Catuaí Amarelo IAC 62' foi submetido ao beneficiamento nesses três equipamentos, em diversas combinações. As frações retidas pelas peneiras 22/64 e 20/64 avos de polegada, na máquina de ventiladores e peneiras, constituíram a maior parte do lote e foram processadas, separadamente, em mesa densimétrica. Foram realizadas avaliações de pureza física, massa de mil sementes, peso hectolítrico, teor de água, tipos de sementes predominantes e integridade do endocarpo. Observou-se que: a) A máquina de pré-limpeza, a máquina de ventiladores e peneiras e a mesa densimétrica foram eficientes para a homogeneização do lote de sementes de café, proporcionando obtenção de melhor qualidade física na seqüência operacional em que foram utilizadas de forma conjugada; b) O uso de peneiras com crivos oblongos e crivos circulares, intercaladas na máquina de ventiladores e peneiras, possibilitou a separação de sementes mocas, de sementes com resíduos de exocarpo aderidos ao endocarpo e de sementes desprovidas de endocarpo, melhorando a aparência do lote; c) A mesa densimétrica foi o equipamento que proporcionou melhor separação de sementes com endocarpo danificado, bem como alterações favoráveis à qualidade física do lote; d) As sementes pequenas, retidas nas menores peneiras da máquina de ventiladores e peneiras, e as sementes de menor massa específica, classificadas ou não por tamanho e coletadas na descarga inferior da mesa densimétrica, foram as de baixa qualidade física.

Beneficiamento de sementes de café e efeitos na qualidade fisiológica

Considerando-se a escassez de informações sobre o beneficiamento mecanizado de sementes de café, realizou-se este trabalho para estudar seus efeitos na qualidade fisiológica das sementes de café arábica. Um lote de sementes de 'Catuaí Amarelo IAC 62' foi submetido à ação de máquina de pré-limpeza, máquina de ventiladores e peneiras e mesa densimétrica, em diversas combinações, e as sementes foram avaliadas quanto à germinação e ao vigor (envelhecimento acelerado, emergência de plântulas, altura e massa de matéria seca de plântulas e mudas). O teor de água das sementes também foi determinado. Utilizou-se o delineamento estatístico de blocos ao acaso, com quatro repetições, e o teste de Tukey a 5% para comparação de médias. Concluiu-se que: a) a qualidade fisiológica das sementes foi aprimorada à medida que o lote passou por equipamentos específicos no beneficiamento, culminando com a melhor qualidade na seqüência operacional em que o lote foi submetido à ação da máquina de ventiladores e peneiras e mesa densimétrica; b) a mesa densimétrica, associada à máquina de ventiladores e peneiras, foi o equipamento que proporcionou a melhor separação de materiais que interferem negativamente na qualidade fisiológica das sementes; c) as sementes maiores e/ou mais pesadas tiveram qualidade fisiológica superior, e as sementes mocas graúdas, qualidade fisiológica similar à das sementes chatas graúdas; d) o descarte das frações do lote constituídas por sementes pequenas ou de menor densidade possibilitou a obtenção de lotes homogêneos e com alta qualidade fisiológica, favorecendo a obtenção de mudas mais vigorosas.

Digital monitoring of mycelium growth kinetics and vigor of shiitake (Lentinula edodes (Berk.) Pegler) on agar medium

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

Triticale, milheto e adubação fosfatada para formação de palhada em semeadura direta

As fontes de P mais utilizadas são os fosfatos solúveis em água, pela maior facilidade de liberação de P no solo. Entretanto, devido às características dos solos tropicais, grande parte desse P acaba adsorvida às partículas do solo, tornando-se indisponível. Os fosfatos reativos podem, inicialmente, liberar o P de maneira mais lenta; entretanto, a partir dos cultivos, este elemento poderá ser liberado de forma contínua, podendo haver menor fixação. O objetivo deste trabalho foi estudar a resposta à aplicação de duas fontes de P na cultura do triticale e o efeito residual dessa adubação no milheto, cultivados em semeadura direta, avaliando-se: fertilidade do solo; produção de matéria seca; teor e quantidade de P nas plantas e palha de cobertura; densidade de plantas; teor e quantidade de P nos grãos; e produtividade do triticale. O experimento foi conduzido em Latossolo Vermelho distroférrico. No mês de abril foram aplicados, a lanço, em superfície, três tratamentos: sem aplicação de P2O5; aplicação de 80 kg ha-1 de P2O5 de superfosfato triplo; e aplicação de 80 kg ha-1 de P2O5 de fosfato natural Arad. em seguida, semeou-se o triticale (X Triticosecale Wittmack), que foi conduzido até a colheita. em setembro, após a colheita do triticale, semeou-se o milheto (Pennisetum glaucum (L.) R. Brown), com o objetivo de elevar a cobertura de palha do solo, sendo ele dessecado no florescimento no mês de novembro. A aplicação de fosfato solúvel em superfície proporcionou lixiviação do P até a camada de 5-10 cm de profundidade do solo e melhor nutrição fosfatada do triticale cultivado em seguida, assim como maior produção de grãos. Apesar do aumento no teor de P disponível no solo, proporcionado pelo fosfato solúvel, a aplicação de P no triticale não redundou em elevação da produção de matéria seca, do teor e da quantidade de P na parte aérea do milheto cultivado em sequência.

Tratamento hidrotérmico na manutenção da qualidade pós-colheita de maracujá-amarelo

Objetivando avaliar o efeito da temperatura de imersão na manutenção da qualidade pós-colheita de frutos de maracujá-amarelo, instalou-se na FCA/UNESP este experimento, composto pelos seguintes tratamentos: T1 (testemunha); T2 (35°C por 2 horas); T3 (35°C por 4 horas); T4 (43°C por 2 horas); T5 (43°C por 4 horas); T6 (53°C por 2 horas); T7 (53°C por 4 horas), sendo os frutos mantidos em câmaras BOD a 12 ± 1 °C e 80-90% UR. A cada três dias, foram retiradas amostras dos tratamentos para as seguintes análises: Grupo destrutivo - pH, firmeza, sólidos solúveis (SS), acidez titulável (AT), relação (SS/AT), rendimento de polpa e vitamina C; e para o grupo-controle determinaram-se perda de massa e coloração da casca. Com base nos resultados obtidos, os tratamentos hidrotérmicos dos frutos, com temperaturas menores, como é o caso do T2 e T3, apresentaram frutos com menor perda de massa, melhor manutenção da coloração, boa manutenção da firmeza da casca e teores razoáveis de vitamina C, enquanto as temperaturas mais elevadas causaram danos à aparência dos frutos (queima da casca) e reduziram os teores de vitamina C na polpa.