Desempenho de sementes de soja revestidas com biopolímeros

The use of biopolymers that help to fix pesticides efficiently and degrade easily without harming the environment, and still improve the physiological performance of field soybean seed may bring contributions to the soybean yield. This study aimed to evaluate the effect of cassava starch polymers (AM), sodium alginate (ALG) and polyvinyl alcohol (PVOH), in the concentrations 2, 4 and 6 g / 100 ml of solution, in the physiological attributes of seeds soy, seed speed soaking and performance of soybean seeds after three months of storage. The soybean variety used was the NK 7059 RR. The experimental design used for the three studies was a factorial with 48 experimental units: 3 polymers (AM, ALG and PVOH), 4 different concentrations (0%, 2%, 4% and 6%), with four replications, in a completely randomized design. It was observed the level of significance of the factors and their interactions, applying the test F. The polymers were evaluated by the Tukey test at 5% probability, and the concentrations were evaluated by polynomial regression. The witness obtained better results for most variables studied. Among the polymers, the best coating was observed PVOH because it was the less viscous polymer and visually not served as a substrate for microorganisms. However, also, satisfactory results were obtained for the AM and ALG polymers at a concentration of 2%. There was not interference of the polymers studied with regard to reduction of imbibition rate of soybean seeds. The hydrophilicity of polymers, mainly the AM and ALG accelerated soaking seeds harming germination at concentrations 4% and 6%. In general, the higher the concentration of polymers tended to worse results.

Efeito da radiação micro-ondas na sinterização em fases sólida e líquida de pós de aço inoxidável 3I6L

Tese submetida à Universidade de Coimbra, Faculdade de Ciências e Tecnologia e aprovada em provas públicas para a obtenção do Grau de Doutor em Engenharia Mecânica (especialidade de Ciência dos Materiais)

Desenvolvimento de filmes nanocompósitos de isolado protéico de corvina (micropogonias furnieri) e argila organofílica

O desenvolvimento de filmes e coberturas é um processo de transformação que utiliza polímeros capazes de formar uma matriz contínua. As proteínas de pescado apresentam propriedades que são vantajosas no preparo de biofilmes, como habilidade para formar redes, plasticidade e elasticidade, apresentando boa barreira ao oxigênio, mas sua barreira ao vapor de água é baixa devido à sua natureza hidrofílica. Estas propriedades podem ser melhoradas aplicando nanotecnologia, incluindo materiais como as nanoargilas. O objetivo do presente trabalho foi desenvolver filmes nanocompósitos a partir de biopolímeros protéicos provenientes de isolados protéicos de corvina (Micropogonias furnieri) e argilas organofílicas. O isolado protéico de corvina (IPC) foi obtido utilizando processo de variação de pH para solubilizar e isolar proteína. Os filmes poliméricos foram desenvolvidos pela técnica de “casting”. Para o desenvolvimento de filmes nanocompósitos de isolado protéico de corvina (IPC) e montmorilonita foi executado um planejamento experimental de 3 níveis e 3 fatores com 3 réplicas no ponto central. Os resultados foram submetidos à metodologia de superfície de resposta (MSR) para estudar os efeitos simultâneos das variáveis independentes, concentração de IPC (IPC = 2; 3,5 e 5 g/100 g de solução filmogênica); concentração de montmorilonita (MMT = 0,3; 0,5 e 0,7 g/100 g de solução filmogênica); e plastificante glicerol (G = 25, 30 e 35 g/100 g de IPC em base seca) sobre as respostas resistência à tração (MPa), elongação (%), força na ruptura (N), permeabilidade ao vapor de água (g mm m-2 d -1 KPa-1 ) e solubilidade (%). O isolado protéico obtido de carne mecanicamente separada de corvina apresentou 97,87% de proteína (em base seca), boa capacidade de retenção de água e solubilidade. Os valores de resistência à tração variaram entre 7,2 e 10,7 MPa e os valores de elongação de 39,6 a 45,8%. Os valores encontrados para PVA no presente trabalho encontram-se entre 3,2 e 5,5 g mm m-2 d -1 KPa-1 . Os filmes nanocompósitos produzidos a partir de IPC e MMT foram promissores, do ponto de vista das propriedades mecânicas, aparência visual e fácil manuseio, bem como baixa permeabilidade ao vapor de água e a baixa solubilidade. Com relação às propriedades mecânicas, a concentração de IPC e MMT foi o principal fator que influenciou no desenvolvimento dos filmes nanocompósitos. O planejamento experimental utilizado determinou que 3,5 g de IPC; 0,5 g de MMT e 30 (g/100g de IPC) de glicerol seriam os parâmetros ideais para desenvolvimento de filmes nanocompósitos utilizando a técnica de “casting”. As coberturas de isolado protéico de corvina (IPC) e as coberturas de IPC e MMT foram aplicadas em mamão minimamente processado para avaliar sua vida- útil. O revestimento com cobertura de isolado protéico de corvina e montmorilonita aplicado em mamão minimamente processado apresentou menor perda de massa 5,26%, menor crescimento microbiano e menor diminuição de firmeza, luminosidade e pH conseqüentemente apresentou os melhores resultados na cobertura de mamão minimamente processado, quando comparados com a amostra controle sem cobertura.

Painéis compósitos de betão leve: comportamento estrutural

Os sucessivos avanços tecnológicos permitem a criação de novos materiais de construção com características otimizadas ao uso que lhes é designado. Nesta categoria enquadram-se os materiais compósitos e mais concretamente os painéis compósitos de betão aligeirado de EPS com revestimento superficial de placas Megapan® estudados neste documento. Neste documento faz-se uma abordagem aos conceitos de material compósito e uma breve análise histórica do seu uso. Descreve-se também sucintamente as características gerais dos painéis em estudo e exemplifica-se algumas aplicações do material até à presente data. São analisados testes de resistência efetuados ao material estudado e efetua-se a caracterização mecânica do mesmo. Verifica-se neste estudo que os painéis de betão aligeirado de EPS com revestimento superficial de placas Megapan® possuem resistências mecânicas que permitem a sua utilização como parte integrante de um sistema estrutural. Sugere-se uma solução construtiva para uma estrutura que utilize os painéis estudados como elemento estrutural e os respetivos pormenores construtivos. É também sugerida uma metodologia de cálculo para dimensionar a estrutura analisada.

Medidas de concentração de radônio proveniente de argamassas de cimento portland, gesso e fosfogesso

Portland cement being very common construction material has in its composition the natural gypsum. To decrease the costs of manufacturing, the cement industry is substituting the gypsum in its composition by small quantities of phosphogypsum, which is the residue generated by the production of fertilizers and consists essentially of calcium dihydrate and some impurities, such as fluoride, metals in general, and radionuclides. Currently, tons of phosphogypsum are stored in the open air near the fertilizer industries, causing contamination of the environment. The 226 Ra present in these materials, when undergoes radioactive decay, produces the 222Rn gas. This radioactive gas, when inhaled together with its decay products deposited in the lungs, produces the exposure to radiation and can be a potential cause of lung cancer. Thus, the objective of this study was to measure the concentration levels of 222Rn from cylindrical samples of Portland cement, gypsum and phosphogypsum mortar from the state of Paraná, as well as characterizer the material and estimate the radon concentration in an environment of hypothetical dwelling with walls covered by such materials. Experimental setup of 222Rn activity measurements was based on AlphaGUARD detector (Saphymo GmbH). The qualitative and quantitative analysis was performed by gamma spectrometry and EDXRF with Au and Ag targets tubes (AMPTEK), and Mo target (ARTAX) and mechanical testing with x- ray equipment (Gilardoni) and the mechanical press (EMIC). Obtained average values of radon activity from studied materials in the air of containers were of 854 ± 23 Bq/m3, 60,0 ± 7,2 Bq/m3 e 52,9 ± 5,4 Bq/m3 for Portland cement, gypsum and phosphogypsum mortar, respectively. These results extrapolated into the volume of hypothetical dwelling of 36 m3 with the walls covered by such materials were of 3366 ± 91 Bq/m3, 237 ± 28 Bq/m3 e 208 ± 21 Bq/m3for Portland cement, gypsum and phosphogypsum mortar, respectively. Considering the limit of 300 Bq/m3 established by the ICRP, it could be concluded that the use of Portland cement plaster in dwellings is not secure and requires some specific mitigation procedure. Using the results of gamma spectrometry there were calculated the values of radium equivalent activity concentrations (Raeq) for Portland cement, gypsum and phosphogypsum mortar, which were obtained equal to 78,2 ± 0,9 Bq/kg; 58,2 ± 0,9 Bq/kg e 68,2 ± 0,9 Bq/kg, respectively. All values of radium equivalent activity concentrations for studied samples are below the maximum level of 370 Bq/kg. The qualitative and quantitative analysis of EDXRF spectra obtained with studied mortar samples allowed to evaluate quantitate and the elements that constitute the material such as Ca, S, Fe, and others.

Nitretação a plasma: fundamentos e aplicações

A nitretação é uma técnica de tratamento de superfície utilizada para endurecer superfícies de metais, principalmente de aços. O uso do plasma para auxiliar esta técnica vem crescendo nos últimos anos. Pelo fato desta técnica utilizar o plasma como fonte energética e este possuir uma vasta aplicação em outras técnicas para processamento de materiais, enobrece ainda mais a leitura do presente livro. Ele apresenta uma revisão da descarga elétrica em gases levando o leitor a refletir, multidisciplinarmente, sobre possibilidades de aplicação da mesma. Apresenta a técnica de nitretação iônica sob o aspecto histórico, científico, tecnológico, operacional e econômico e, finalmente, faz uma revisão das novas técnicas de endurecimento superficial assim como as técnicas convencionais de nitretação

Argamassas de terra e cal - Características e campos de aplicação

As argamassas mistas de cal e terra devem ter resultado da prática profissional quando as condições económicas foram possibilitando a adição de cais aérea às argamassas vernaculares só de terra. Baixas adições de cal aérea a argamassas de terra têm conduzido a drásticas alterações da cor e das resistências mecânicas das argamassas de terra. No entanto, a substituição parcial de massa de cal por terra em argamassas de cal ao traço volumétrico 1:2 (correspondendo a argamassas com traço em massa de 1:8, com substituições de 10% a 50%) resulta em argamassas mais ecológicas e que tecnicamente indiciam ser adequadas para aplicação em rebocos de edifícios antigos e mesmo em construção nova com características compatíveis. Os resultados obtidos foram particularmente interessantes para uma substituição de 10% mas muito há ainda a fazer para um conhecimento aprofundado deste tipo de argamassas mistas de cal e terra, muito utilizadas no passado, com vista à otimização de formulações que possam vir a ser aplicadas correntemente.

Estudo das principais argamassas utilizadas na reabilitação de edifícios antigos

Com o passar dos anos, as obras mais sublimes, começam a mostrar marcas subtis ou profundas de deterioração, como por exemplo: fissurações e defeitos associados à humidade. Estes são reflexo de fatores externos, como fungos, a própria atmosfera reativa, mudanças climatéricas e, até mesmo, a ação do homem. Neste seguimento pretende-se estudar as principais argamassas utilizadas na reabilitação de edifícios antigos, principalmente, as argamassas utilizadas no decorrer das obras ao longo do estágio, com o objetivo de comparar as suas caraterísticas, sendo estas argamassas tradicionais e pré-fabricadas. Foram feitos vários ensaios para determinar as suas resistências mecânicas, nomeadamente, o ensaio de resistência à flexão e compressão em diferentes idades após a confeção das argamassas, e ensaios para determinar a sua durabilidade como o ensaio de absorção da água por capilaridade; ensaio de absorção de água por imersão às 48horas (pressão atmosférica); ensaio para determinação do teor de água às 48horas e o ensaio de arrancamento (pull-off). A análise dos resultados mostrou que as argamassas adquirem mais resistência com o passar do tempo após a sua confeção, e que as argamassas dos provetes obtidos de forma tradicional, constituídos por argamassa de cal Hidráulica (HL5) e argamassa de cimento, apresentam melhores resultados do que a argamassa pré-fabricada (weber.cal classic).

Fire protection durability of intumescent coatings after accelerated aging

The most common method of achieve the required fire resistance is by the use of passive fire protection systems, being intumescent coatings the fire protection material frequently used. These are usually considered thin film coatings as they are applied with a dry film thickness (DFT) between 0.3-3 [mm]. The required DFT is obtained by experimental fire resistance tests performed to assess the contribution of this reactive fire protection material to the steel member fire resistance. This tests are done after dry coating and a short time period of atmospheric conditioning, at constant temperature and humidity. As the coatings formulation is mainly made from polymeric basis compounds, it is expected that the environmental factors, such temperature, humidity and UV radiation (UVA and UVB) significantly affect the intumescent coating fire protection performance and its durability. This work presents a research study about the effects of aging on the fire protection performance of intumescent coatings. A commercial water based coating is submitted to an accelerated aging cycle, using a QUV Accelerated Weathering Tester. This tests aim to simulate 10 years of the coating natural aging. The coating durability is tested comparing the fire protection of small steel samples submitted to a radiant heat flux exposure from a cone calorimeter. In total, 28 tests were performed on intumescent coating protected steel specimens, of which 14 specimens were tested before the hydrothermal aging test and other 14 after accelerated aging. The experimental tests results of the steel temperature evolution shows that increasing the intumescent dry coating film thickness, the fire resistance time increases. After the accelerated aging cycles, the coating lose their ability to expand, resulting in an increase of the steel temperature of approximately 200 [ºC], compared to the samples without aging.

Contributo de betões de cânhamo na regulação passiva da humidade no interior dos edifícios

Verifica-se um crescimento no interesse do uso de materiais de construção amigos do ambiente, tais como o betão de cânhamo, devido à necessidade de minimizar o impacto ambiental do sector da construção nas mudanças climáticas. O betão de cânhamo possui reduzida energia incorporada durante o processo de fabrico devido à sua composição: elevado teor de fibras de cânhamo, um ligante e água que formam uma pasta que aglutina as fibras. Este material de construção pode ser utilizado em elementos de alvenaria leves ou, geralmente, em placas de revestimento e isolamento. É muito higroscópico, podendo trazer vantagens a nível de economia energética, bem como da saúde e conforto térmico dos habitantes do espaço onde é aplicado. Apresenta-se um estudo experimental que teve como objetivo comparar a higroscopicidade de três tipos de betões de cânhamo e a correspondente capacidade de contribuírem para a regulação da humidade relativa (HR) no interior dos edifícios. Os betões diferem fundamentalmente no tipo de ligante utilizado nas suas formulações: cal aérea (PF70), cal hidráulica (Calco) e um ligante não identificado produzido pelo Grupo Parex (NL). Pretendeu-se ainda avaliar a contribuição da espessura de material nessa função de regulação passiva da HR. Provetes com distintas espessuras dos três betões foram sujeitos ao ensaio de determinação do Moiture Buffering Value (MBV), com ciclos diários de variação de HR: 8h a 75% de HR e 16h a 33% de HR em condições isotérmicas (23°C). Registou-se um bom MBV e não foi detetada uma diferença significativa na capacidade higroscópica dos diferentes betões, formulados com os distintos ligantes. A análise dos resultados, feita com o auxílio de modelos teóricos, permitiu destacar que a espessura envolvida na regulação da HR se mantém, na generalidade, limitada a 5cm em todas as formulações em estudo. Contudo, algumas irregularidades da superfície podem ter um forte impacto sobre a espessura ativa.

Desenvolvimento de formulações para produção de grés porcelanato a partir de matérias-primas da região da bacia do Parnaíba

Brazil is a great ceramic raw materials productor because of the its big number of clay deposits, in various areas of the ceramic industry. Although, the majority of the natural reservations are unknown or not studied yet, so there is no scientific technical dates that can guide their usage and industrial application, as well as the racional and optimazed way of usage by the industrial sector. The state of Maranhão has a gigant mineral wealth as esmectite, bentonite, kaolin, clays, feldspates, marine salt, iron and others, but produce only products with small agregated value compared to the porcelanato, one of the most expensives ceramic cover tiles, the reason for that is the low water absorption (lower than 0,5%), beside present amazing tecnicals features, like mechanical resistence. The main objective of the work is to do the characterization of four clays, with the finallity of find an application by the results and develop formulations to produce porcelanato using these raw materials from Timon-MA. For this were made the raw materials characterization using X ray fluorecence; X ray diffraction; Differencial thermal analysis; Dilatometric analysis and Tecnological properties, planing three formulations that were sinterized at six different temperatures: 1150, 1170, 1190, 1210, 1230 and 1250ºC for 7 minutes. After the sinteratization, the samples were submitted to tension resistance analysis. Were attained two formulations with the requested properties to produce porcelanato

Influência da vermiculita expandida na resistência à compressão e reologia de pastas cimentantes de poços de petróleo

Several problems related to the loss of hydraulic seal in oilwells, causing gas migration and/or contamination of the production zone by water, have been reported. The loss of the hydraulic seal is a consequence of cracks which can be occasioned either by the invasion of gas during the wait on cement or by the expansion of the casing causing the fracture of the cement sheath. In case of the pressure of the formation is higher than the pressure in the annulus, gas can migrate into the slurry and form microannulus, which are channels where gas migrates after the cement is set. Cracks can be also occasioned by the fracture of the cement sheath when it does not withstand the thermal and dynamic loads. In reservoirs where the oil is heavy, steam water injection operation is required in order to get the oil flowing. This operation increases the temperature of the casing, and then it expands and causes the fracture of the cement sheath in the annulus. When the failures on the cement are detected, remedial cementing is required, which raise costs caused by the interventions. Once the use of cement in the construction civil sector is older than its use in the petroleum sector, it is common to bring technologies and solutions from the civil construction and apply them on the petroleum area. In this context, vermiculite, a mineral-clay widely encountered in Brazil, has been used, on its exfoliated form, in the civil construction, especially on the manufacture of lights and fireproof concretes with excellent thermal and acoustical properties. It has already been reported in scientific journals, studies of the addition of exfoliated vermiculite in Portland cements revealing good properties related to oilwell cementing operations. Thus, this study aimed to study the rheological behavior, thickening time, stability and compressive strength of the slurries made of Portland cement and exfoliated vermiculite in 5 different compositions, at room temperature and heated. The results showed that the compressive strength decreased with the addition of exfoliated vermiculite, however the values are still allowed for oiwell cementing operations. The thickening time of the slurry with no exfoliated vermiculite was 120 min and the thickening time of the slurry with 12 % of exfoliated vermiculite was 98 min. The stability and the rheological behavior of the slurries revealed that the exfoliated vermiculite absorbed water and therefore increased the viscosity of the slurries, even though increasing the factor cement-water. The stability experiment carried out at 133 ºF showed that, there was neither sedimentation nor reduction of the volume of the cement for the slurry with 12 % of exfoliated vermiculite. Thus, the addition of exfoliated vermiculite accelerates the set time of the cement and gives it a small shrinkage during the wait on cement, which are important to prevent gas migration

Análise do comportamento reológico de pastas de cimento contendo resíduos de pneu para poços de petróleo

The low tenacity presented by the Portland cement pastes used in the oil wells cementation has been motivating several researches with attention focused on alternative materials. Additives have been developed to generate flexible pastes with mechanical resistance capable to support the expansions and retractions of the metallic covering of the wells that submit to the steam injection, technique very used to increase the recovery factor in oil reservoirs with high viscosity. A fresh paste with inadequate rheological behavior may commit the cementation process seriously, involving flaws that affect the performance of the paste substantially in the hardened state. This work proposes the elaboration and the rheological analysis of Portland cement pastes with addition of residues of rubber tire in several proportions, with the aim of minimizing the damages provoked in the hem cementing of these wells. By thermogravimetric analysis, the particles of eraser that go by the sieve of 0,5mm (35 mesh) opening and treated superficially with NaOH solution of 1 mol/L presented appropriate thermal resistance for wells that submit to thermal cyclic. The evaluation of the study based on the results of the rheological analysis of the pastes, complemented by the mechanical analysis, thickening, stability, tenor of free water and filtrate loss, being used as parameter a paste reference, without rubber addition. The results showed satisfactory rheology, passive of few corrections; considerable loss of mechanical resistance (traction and compression), compensated by earnings of tenacity, however with established limits for its application in oil wells; satisfactory stability, free water and thickening time

Adição de vermiculita expandida mícron em pastas de baixa densidade para cimentação de poços de petróleo

The northeastern region of Brazil has a large number of wells producing oil using a method of secondary recovery steam injection, since the oil produced in this region is essentially viscous. This recovery method puts the cement / coating on thermal cycling, due to the difference in coefficient of thermal expansion between cement and metal coating causes the appearance of cracks at this interface, allowing the passage of the annular fluid, which is associated with serious risk socioeconomic and environmental. In view of these cracks, a correction operation is required, resulting in more costs and temporary halt of production of the well. Alternatively, the oil industry has developed technology for adding new materials in cement pastes, oil well, providing high ductility and low density in order to withstand the thermo-mechanical loads generated by the injection of water vapor. In this context, vermiculite, a clay mineral found in abundance in Brazil has been applied in its expanded form in the construction industry for the manufacture of lightweight concrete with excellent insulation and noise due to its high melting point and the presence of air in their layers lamellar. Therefore, the vermiculite is used for the purpose of providing low-density cement paste and withstand high temperatures caused by steam injection. Thus, the present study compared the default folder containing cement and water with the folders with 6%, 8% and 10% vermiculite micron conducting tests of free water, rheology and compressive strength where it obtained the concentration of 8 % with the best results. Subsequently, the selected concentration, was compared with the results recommended by the API standard tests of filtered and stability. And finally, analyzed the results from tests of specific gravity and time of thickening. Before the study we were able to make a folder with a low density that can be used in cementing oil well in order to withstand the thermo-mechanical loads generated by steam injection

Desenvolvimento de tubulação em compósito polimérico revestida externamente com poliuretano de alta densidade

Pipelines for the transport of crude oil from the production wells to the collecting stations are named production lines . These pipes are subjected to chemical and electrochemical corrosion according to the environment and the type of petroleum transported. Some of these lines, depending upon the composition of the fluid produced, may leak within less than one year of operation due to internal corrosion. This work aims at the development of composite pipes with an external protecting layer of high density polyurethane for use in production lines of onshore oil wells, meeting operational requirements. The pipes were manufactured using glass fibers, epoxy resin, polyester resin, quartz sand and high density polyurethane. The pipes were produced by filament winding with the deposition of high density polyurethane on the external surface and threaded ends (API 15 HR/PM-VII). Three types of pipes were manufactured: glass/epoxy, glass/epoxy with an external polyurethane layer and glass/epoxy with an intermediate layer of glass fiber, polyester, sand and with an external polyurethane layer. The three samples were characterized by Scanning Electronic Microscopy (SEM) and for the determination of constituent content. In addition, the following tests were conducted: hydrostatic test, instant rupture, shorttime failure pressure, Gardner impact, transverse stiffness and axial tension. Field tests were conducted in Mossoró RN (BRAZIL), where 1,677 meters of piping were used. The tests results of the three types of pipes were compared in two events: after two months from manufacturing of the samples and after nine months of field application. The results indicate that the glass/epoxy pipes with an intermediate layer of fiber glass composite, polyester e sand and with an external layer of high density polyurethane showed superior properties as compared to the other two and met the requirements of pressure class, axial tensile strength, transverse stiffness, impact and environmental conditions, for onshore applications as production lines