Avaliação da influência de cinza da casca de arroz em cimentos para poços de petróleo submetidos à injeção de vapor

Reservoirs that present highly viscous oils require methods to aid in their recovery to the surface. The elev ated oil viscosity hinders its flow through porous media and conventional recovery methods have not obtained significant efficiency. As such, the injection of steam into the reservoir through an injection well has been the most widely used method of therma l recovery, for it allows elevated volumes of recovery due to the viscosity reduction of the oil, facilitating the oil’s mobility within the rock formation and consequently into the production well where it will be exploited. On the other hand, the injecti on of vapor not only affects the fluids found in the rock pores, but the entire structure that composes the well where it is injected due to the high temperatures used in the process. This temperature increment is conducted to the cement, found in the annu lus, responsible for the isolation of the well and the well casing. Temperatures above 110 ̊C create new fazes rich in calcium in the cement matrix, resulting in the reduction of its permeability and the consequential phenomenon of mechanical resistance ret rogression. These alterations generate faults in the cement, reducing the well’s hydraulic isolation, creating insecurity in the operations in which the well will be submitted as well as the reduction of its economic life span. As a way of reducing this re trograde effect, this study has the objective of evaluating the incorporation of rice husk ash as a mineral additive substitute of silica flour , commercially utilized as a source of silica to reduce the CaO/SiO 2 ratio in the cement pastes submitted to high temperatures in thermal recovery. Cement pastes were formulated containing 20 and 30% levels of ash, apart from the basic paste (water + cement) and a reference paste (water + cement + 40% silica flour) for comparison purposes. The tests were executed th rough compression resistance tests, X - Ray diffraction (XRD) techniques, thermogravimetry (TG), scanning electron microscopy (SEM) and chemical anal ysis BY X - ray fluorescence (EDS) on the pastes submitted to cure at low temperatures (45 ̊C) for 28 days following a cure at 280 ̊C and a pressure of 2,000 PSI for 3 days, simulating vapor injection. The results obtained show that the paste containing 30% r ice shell ash is satisfactory, obtaining mechanical resistance desired and equivalent to that of the paste containing 40% silica flour, since the products obtained were hydrated with low CaO/SiO 2 ratio, like the Tobermorita and Xonotlita fases, proving its applicability in well subject to vapor injection.

Desenvolvimento de pastas cimentantes contendo nanossílica como material estendedor para aplicação em fases iniciais, de poços petrolíferos, submetidas à baixa temperatura (5°c ± 3ºc)

The improved performance of hydraulic binders, the base of Portland cement, consists in the careful selection and application of materials that promote greater durability and reduced maintenance costs There is a wide variety of chemical additives used in Portland cement slurries for cementing oil wells. These are designed to work in temperatures below 0 ° C (frozen areas of land) to 300 ° C (thermal recovery wells and geothermal); pressure ranges near ambient pressure (in shallow wells) to greater than 200 MPa (in deep wells). Thus, additives make possible the adaptation of the cement slurries for application under various conditions. Among the materials used in Portland cement slurry, for oil wells, the materials with nanometer scale have been applied with good results. The nanossílica, formed by a dispersion of SiO2 particles, in the nanometer scale, when used in cement systems improves the plastic characteristics and mechanical properties of the hardened material. This dispersion is used commercially as filler material, modifier of rheological properties and / or in recovery processes construction. It is also used in many product formulations such as paints, plastics, synthetic rubbers, adhesives, sealants and insulating materials Based on the above, this study aims to evaluate the performance of nanossílica as extender additive and improver of the performance of cement slurries subjected to low temperatures (5 ° C ± 3 ° C) for application to early stages of marine oil wells. Cement slurries were formulated, with densities 11.0;12.0 and 13.0 ppg, and concentrations of 0; 0.5, 1.0 and 1.5%. The cement slurries were subjected to cold temperatures (5 ° C ± 3 ° C), and its evaluation performed by tests rheological stability, free water and compressive strength in accordance with the procedures set by API SPEC 10A. Thermal characterization tests (TG / DTA) and crystallographic (XRD) were also performed. The use of nanossílica promoted reduction of 30% of the volume of free water and increased compression resistance value of 54.2% with respect to the default cement slurry. Therefore, nanossílica presented as a promising material for use in cement slurries used in the early stages of low-temperature oil wells

Predição de séries temporais de parâmetros de redes HSPA - WCDMA

With the growing demand of data traffic in the networks of third generation (3G), the mobile operators have attempted to focus resources on infrastructure in places where it identifies a greater need. The channeling investments aim to maintain the quality of service especially in dense urban areas. WCDMA - HSPA parameters Rx Power, RSCP (Received Signal Code Power), Ec/Io (Energy per chip/Interference) and transmission rate (throughput) at the physical layer are analyzed. In this work the prediction of time series on HSPA network is performed. The collection of values of the parameters was performed on a fully operational network through a drive test in Natal - RN, a capital city of Brazil northeastern. The models used for prediction of time series were the Simple Exponential Smoothing, Holt, Holt Winters Additive and Holt Winters Multiplicative. The objective of the predictions of the series is to check which model will generate the best predictions of network parameters WCDMA - HSPA.

Influência do retardante de chamas nas propriedades mecânicas e flamabilidade em compósitos poliméricos de epóxi/fibra de curauá

Currently, there is a great search for materials derived from renewable sources. The vegetable fibers as reinforcement for polymer matrixes, has been used as an alternative to replace synthetic fibres, being biodegradable and of low cost. The present work aims to develop a composite material with epoxy resin reinforced with curauá fibre with the addition of alumina trihydrate (aluminum hydroxide, Al(OH)3) as a flame retardant, which was used in proportions of 10 %, 20% and 30% of the total volume of the composite. The curauá fibers have gone through a cleaning process with an alkaline bath of sodium hydroxide (NaOH ), parallelized by hand and cut carding according to the default length . They were molded composites with fibers 30cm. Composites were molded in a Lossy Mold with unidirectional fibres in the proportion of 20% of the total volume of the composite. The composites were prepared in the Chemical Processing Laboratory of the Textile Engineering Department at UFRN. To measure the performance of the material, tests for the resistance to traction and flexion were carried out. with samples that were later analyzed in the Electronic Microscopy Apparatus (SEM ). The composites showed good mechanical properties by the addition of flame retardant and in some cases, leaving the composite more vulnerable to breakage. These mechanical results were analyzed by chi-square statistical test at the 5% significance level to check for possible differences between the composite groups. Flammability testing was conducted based on the standard Underwriters Laboratory 94 and the material showed a satisfactory result taking their average burn rate (mm / min) decreasing with increasing addition of the flame retardant composite.

Influência do tempo de adição do policarboxilato em pastas de cimento Portland para cimentação de poços petrolíferos

Cement pastes used in cementing oil wells operations are prepared according to the specific characteristics of each well. The physical properties requested for each folder formulation depend on the temperature and pressure of the well to be cemented. The rheological properties of the pulp are important control parameter for efficiency in transportation and positioning the folder during the cementing operation. One of the main types of additive used for the adjustment of rheological properties of cement pastes is the dispersant additive. This work aims to study the influence of variation of the time of addition of the polycarboxylate (0, 5, 10 and 15 minutes) in cement pastes, considering the initial periods of hydration of cement particles as fundamental point for better performance dispersant additive. Pastes were prepared with a density set at 15.6 lb/gal (1.87 g/cm3) and polycarboxylate concentrations ranging from 0.01 gpc to 0.05 gpc circulation temperature (BHCT) of 51°C and static temperature (BHST) of 76 C. The pastes were characterized from a rheological measurements, volume filtered, thickening time and resistance to compression formulations. Also were carried out tests Diffraction X-ray (XRD) and Scanning Electron Microscopy (MEV). The results showed that the addition of policaboxilato after 15 minutes decreased by 70% the values of rheological parameters. According to results of DRX and MEV, the addition of dispersant after 15 minutes did not affect the chemical reactions and subsequent formation of cement hydration products. A study of the economic feasibility to realize the financial benefits of the technique, which can be seen only with the use of the technique in this work to reduce the cost of production of cement paste was carried out, can get up to $ 1015.00 for each folder 100 barrels produced with said formulations.

Influência do tempo de adição do policarboxilato em pastas de cimento Portland para cimentação de poços petrolíferos

Cement pastes used in cementing oil wells operations are prepared according to the specific characteristics of each well. The physical properties requested for each folder formulation depend on the temperature and pressure of the well to be cemented. The rheological properties of the pulp are important control parameter for efficiency in transportation and positioning the folder during the cementing operation. One of the main types of additive used for the adjustment of rheological properties of cement pastes is the dispersant additive. This work aims to study the influence of variation of the time of addition of the polycarboxylate (0, 5, 10 and 15 minutes) in cement pastes, considering the initial periods of hydration of cement particles as fundamental point for better performance dispersant additive. Pastes were prepared with a density set at 15.6 lb/gal (1.87 g/cm3) and polycarboxylate concentrations ranging from 0.01 gpc to 0.05 gpc circulation temperature (BHCT) of 51°C and static temperature (BHST) of 76 C. The pastes were characterized from a rheological measurements, volume filtered, thickening time and resistance to compression formulations. Also were carried out tests Diffraction X-ray (XRD) and Scanning Electron Microscopy (MEV). The results showed that the addition of policaboxilato after 15 minutes decreased by 70% the values of rheological parameters. According to results of DRX and MEV, the addition of dispersant after 15 minutes did not affect the chemical reactions and subsequent formation of cement hydration products. A study of the economic feasibility to realize the financial benefits of the technique, which can be seen only with the use of the technique in this work to reduce the cost of production of cement paste was carried out, can get up to $ 1015.00 for each folder 100 barrels produced with said formulations.

Mídia à luz do desejo: cartografias dos processos da mídia livre contemporânea brasileira

This paper aims to understand the specifics of the network communication and the logic of articulation of social insurgencies in contemporary inferred from the rizome concept coined by Felix Guattari and Gilles Deleuze and the multitude as preach Michael Hardt and Antonio Negri. To do so, it raises the processes and practices of political bodies, reaching lines and common strategies of operation. Unless the specifics, it is possible to draw a continuous and rizomatic communication that traverses both bodies enrolled in institutionalized democracy, as the spanish movement-party Podemos and the greek coalition Syriza, as the autonomous collectives, such as the Movimento Passe Livre, fighting for universal public, free and quality transport, and the free media initiatives Media Ninja and Catarina Santos, willing to understand the social movements. The constitutional amendment of this model of communication networking seems to be the desire to radicalization of democracy, the bias of Ernesto Laclau and Chantal Mouffe, as a strategic and common struggle. Indeed, speaking specifically of free media, they are built from here processes that take place in understanding the agency of the bodies as relevant to political action toward the radical democracy project, and the use of free softwares, the communicator-protester agency, the performance, the collective experience.

O ensino e a aprendizagem da multiplicação no 2.º ano de escolaridade

No âmbito da didática da Matemática, e seguindo as tendências do paradigma de professor investigador, decidi debruçar-me sobre a introdução da aprendizagem da multiplicação em alunos de 2.º ano de escolaridade, aplicando um conjunto de tarefas que visam o desenvolvimento do conceito de multiplicação nos sentidos aditivo e combinatório e a aplicação das propriedades da multiplicação. Foram analisadas as interações e principalmente as estratégias utilizadas pelos alunos perante tarefas propostas, que na sua maioria abordavam contextos que lhes eram familiares. Pretendeu-se que os alunos desenvolvessem o conceito de multiplicação de forma gradual e natural. Para o desenvolvimento deste estudo, que se configura como uma investigação sobre a minha prática, foi utilizada uma metodologia qualitativa de cariz exploratório, descritivo e interpretativo. Foi possível verificar que os alunos encararam as tarefas e a operação, nelas, desenvolvida com agrado e motivação. Os resultados deste estudo indicam que os alunos compreenderam os conceitos da multiplicação explorados ao longo da cadeia de tarefas aplicada e foram evoluindo favoravelmente as suas estratégias multiplicativas. A partilha de estratégias nas discussões coletivas permitiu-nos uma melhor perceção das ideias dos alunos bem como das suas dúvidas/dificuldades o que fez surgir novas estratégias e com certeza enriqueceu o conhecimento dos alunos e o meu como professora. Este estudo reafirma a importância da reflexão contínua por parte dos docentes perante o desenvolvimento dos conhecimentos dos alunos e das suas próprias práticas.

Perceção da Dor Crónica e Estratégias Adaptativas em Famílias de Doentes Oncológicos

Objetivos: A presente investigação tem como principais objetivos a avaliação da perceção da dor crónica oncológica por parte de doentes e seus familiares, bem como a análise da relação entre a dor crónica percebida e as estratégias de adaptação que as famílias usam para responder à situação de doença e à dor. Metodologia: Este é um estudo descritivo e correlacional, de análise univariada. Na recolha dos dados, utilizámos o Family Crisis Oriented Personal Evaluyation Scales (FCOPES) para verificar a resposta familiar a momentos de crise, o Social Support Questionnaire - Short Form (SSQ6) para avaliar o suporte social percebido e, por fim, a Escala Visual Analógica (Eva) para determinar a dor percebida pelo doente e pela família. Participantes: A amostra é constituída por 32 familiares de doentes com diagnóstico de cancro acompanhados na Consulta da Dor do IPOCFG, EPE. Os familiares da nossa amostra têm em média de 57 anos de idade, 53,1% são do sexo feminino e é composta por 65,6% de cônjuges. Desta amostra, 28 (87,5%) dos familiares assumem o papel de cuidadores principais e 21 (65,6%) habitam o mesmo lar. Resultados: Verificou-se que as famílias possuem uma resposta familiar a momentos de crise na família e um alto nível de perceção das estratégias de coping. Concluiu-se, ainda, que os familiares estão satisfeitos com o suporte social (M=30,84) que lhes é proporcionado. Relativamente à perceção de dor, os resultados sugerem que os familiares cuidadores pontuam valores mais elevados. Conclusões: A investigação revela que os familiares usam estratégias de coping, não sendo estas influenciadas pelo sexo, idade, cuidador, agregado familiar e classificação de dor. Quanto à perceção da dor fica claro que os familiares compreendem e vivenciam a experiência da dor de uma forma muito semelhante à do próprio doente, registando os homens níveis mais elevados de dor percebida quando comparados com os familiares do género feminino. No entanto, foi possível perceber que o acompanhamento psicológico deveria ser um aditivo importante e parte integrante do tratamento, visto que pode proporcionar ao doente uma melhor qualidade de vida e aos seus familiares.

Efectos de los procesos de ultrafiltración y de hidrólisis enzimática sobre las propiedades funcionales del plasma bovino deshidratado

En la Argentina la sangre obtenida del faenado del ganado bovino es considerada un subproducto de menor valor, a pesar de su alto contenido de proteínas de gran calidad. A diferencia de lo que ocurre en algunos países, en los cuales la sangre (o alguno de sus componentes) se utiliza como complemento alimenticio humano, en nuestro país sólo una pequeña fracción de la sangre recolectada es aprovechada, destinándola principalmente a consumo animal. En este trabajo de Tesis se evaluó el potencial como aditivo alimentario humano del plasma bovino deshidratado, un derivado de la sangre bovina que se utiliza únicamente como complemento nutricional animal. En la Primera Parte de este trabajo se obtuvo Plasma Desmineralizado mediante un proceso de diafiltración y se evaluaron algunas de sus propiedades funcionales (Solubilidad, Capacidad de Retención de Agua, capacidad de Retención de Aceite, Capacidad Emulsionante, Capacidad Espumante y Capacidad Antioxidante), comparándolas con las del plasma sin diafiltrar. Como resultado de las tareas llevadas a cabo en esta Primera Parte, se lograron establecer las condiciones operativas para efectuar el proceso de diafiltración de manera eficaz y se pudo evaluar el efecto de dicho proceso sobre las Propiedades Funcionales del plasma consideradas. La Solubilidad del plasma resultó alta en un amplio rango de pH, e incluso mejoró luego del proceso de diafiltración en algunos valores de pH. Los procesos realizados al plasma aumentaron su Capacidad de Retención de Agua; en cambio, su Capacidad de Retención de Aceite disminuyó. El plasma mostró una Capacidad Emulsionante acorde a lo descripto en la bibliografía; la diafiltración y la posterior deshidratación no la afectaron, pero sí aumentaron la estabilidad de las emulsiones formadas. El plasma mostró una gran capacidad para formar espumas estables, las cuales no resultaron afectadas por los procesos efectuados sobre el mismo. El plasma deshidratado original mostró una Capacidad Antioxidante similar a la descripta en la bibliografía. El efecto del proceso de diafiltración sobre la misma no pudo ser establecido. En la Segunda Parte de este trabajo se obtuvieron dos hidrolizados enzimáticos a partir del plasma, utilizando la enzima Alcalase, con diferentes grados de hidrólisis. Se evaluaron las propiedades funcionales de los hidrolizados, comparándolas entre sí y con las del plasma original. Como resultado de estas tareas se definieron las condiciones del proceso de hidrólisis, comprobándose la obtención de fragmentos proteicos y péptidos de distinto tamaño molecular. Con respecto a las Propiedades Funcionales, los hidrolizados obtenidos resultaron ligeramente más solubles que el plasma deshidratado original, y la hidrólisis con Alcalase afectó notoriamente a las propiedades surfactantes de las proteínas plasmáticas, tanto a la Capacidad Emulsionante como a la Capacidad Espumante. En cambio, la hidrólisis enzimática aumentó marcadamente la Capacidad Antioxidante del plasma deshidratado. Los hidrolizados obtenidos presentaron una actividad de secuestro de radicales libres significativamente mayor que la del plasma original, y esa mayor actividad antioxidante resultó asociada al menor tamaño de los péptidos obtenidos. En virtud de los resultados obtenidos, se concluye que el plasma bovino deshidratado, tanto en su forma original como desmineralizado, tiene potenciales aplicaciones como aditivo alimentario para mejorar algunas propiedades funcionales de los alimentos, y que los hidrolizados que se obtuvieron de él con la enzima Alcalase poseen una alta capacidad antioxidante, que los haría viables para ser utilizados como aditivos conservantes para prolongar la vida útil de los alimentos. De ser viable su uso en alimentos humanos, esto aumentaría el valor agregado de este subproducto de la industria cárnica. Por último, se discuten algunas líneas de trabajo que deberían realizarse para completar su posible implementación en la industria alimenticia humana.

“Adição ao Jogo online”

Esta dissertação visa compreender a adição ao jogo online, através de duas perspetivas complementares que se congregam num estudo de caso. Analisamos o discurso de um jogador predominantemente de Blackjack online adicto a esta prática (F.) em processo de desabituação, e desenvolvemos a mesma metodologia junto da mãe deste, enquanto fonte complementar de informação, através de entrevistas semi-estruturadas. Desta análise emergiram resultados que clarificam os fatores que funcionam como determinantes da adição, que a mantêm bem como elementos indispensáveis para compreender a decisão de paragem do jogo. Nesta dinâmica conjugamos a perspetiva de F e da sua mãe. A metodologia escolhida para análise dos dados de investigação foi a Grounded Analysis Theory, partindo das vozes dos dois participantes e tendo como objetivo a construção de uma narrativa alternativa e assim contribuir para uma melhor análise de compreensão dos dados obtidos. Através de um processo indutivo de produção de conhecimento organizado e obedecendo a uma sequência que busca uma maior complexidade de integração, tem como objetivo final gerar uma teoria sustentada nos dados recolhidos (Fernandes & Maia, 2001). Enquanto metodologia qualitativa permite-nos aceder aos significados múltiplos que emergiram da experiência destes dois participantes. O jogo online sustentado na sua fácil disponibilidade tem como consequência um maior isolamento do jogador, e uma vez que as recompensas financeiras são uma possibilidade alimenta o ciclo do comportamento aditivo. A observância de problemas físicos e psicológicos percebidos como graves, justificaram uma abordagem de tratamento multidisciplinar, envolvendo ajuda farmacológica, psicológica e social. Os estudos existentes sobre o jogo online são ainda muito escassos, justificandose o estudo qualitativo na construção do conhecimento, pela análise mais detalhada dos fatores que podem contribuir para uma melhor compreensão de todas as especificidades presentes, numa perturbação aditiva ao jogo online.

Electrolytes for ceramic oxide fuel cells

The main objective of this dissertation is the development and processing of novel ionic conducting ceramic materials for use as electrolytes in proton or oxide-ion conducting solid oxide fuel cells. The research aims to develop new processing routes and/or materials offering superior electrochemical behavior, based on nanometric ceramic oxide powders prepared by mechanochemical processes. Protonic ceramic fuel cells (PCFCs) require electrolyte materials with high proton conductivity at intermediate temperatures, 500-700ºC, such as reported for perovskite zirconate oxides containing alkaline earth metal cations. In the current work, BaZrO3 containing 15 mol% of Y (BZY) was chosen as the base material for further study. Despite offering high bulk proton conductivity the widespread application of this material is limited by its poor sinterability and grain growth. Thus, minor additions of oxides of zinc, phosphorous and boron were studied as possible sintering additives. The introduction of ZnO can produce substantially enhanced densification, compared to the un-doped material, lowering the sintering temperature from 1600ºC to 1300ºC. Thus, the current work discusses the best solid solution mechanism to accommodate this sintering additive. Maximum proton conductivity was shown to be obtained in materials where the Zn additive is intentionally adopted into the base perovskite composition. P2O5 additions were shown to be less effective as a sintering additive. The presence of P2O5 was shown to impair grain growth, despite improving densification of BZY for intermediate concentrations in the range 4 – 8 mol%. Interreaction of BZY with P was also shown to have a highly detrimental effect on its electrical transport properties, decreasing both bulk and grain boundary conductivities. The densification behavior of H3BO3 added BaZrO3 (BZO) shows boron to be a very effective sintering aid. Nonetheless, in the yttrium containing analogue, BaZr0.85Y0.15O3- (BZY) the densification behavior with boron additives was shown to be less successful, yielding impaired levels of densification compared to the plain BZY. This phenomenon was shown to be related to the undesirable formation of barium borate compositions of high melting temperatures. In the last section of the work, the emerging oxide-ion conducting materials, (Ba,Sr)GeO3 doped with K, were studied. Work assessed if these materials could be formed by mechanochemical process and the role of the ionic radius of the alkaline earth metal cation on the crystallographic structure, compositional homogeneity and ionic transport. An abrupt jump in oxide-ion conductivity was shown on increasing operation temperature in both the Sr and Ba analogues.

Hybrid materials for biomedical applications

The increased longevity of humans and the demand for a better quality of life have led to a continuous search for new implant materials. Scientific development coupled with a growing multidisciplinarity between materials science and life sciences has given rise to new approaches such as regenerative medicine and tissue engineering. The search for a material with mechanical properties close to those of human bone produced a new family of hybrid materials that take advantage of the synergy between inorganic silica (SiO4) domains, based on sol-gel bioactive glass compositions, and organic polydimethylsiloxane, PDMS ((CH3)2.SiO2)n, domains. Several studies have shown that hybrid materials based on the system PDMS-SiO2 constitute a promising group of biomaterials with several potential applications from bone tissue regeneration to brain tissue recovery, passing by bioactive coatings and drug delivery systems. The objective of the present work was to prepare hybrid materials for biomedical applications based on the PDMS-SiO2 system and to achieve a better understanding of the relationship among the sol-gel processing conditions, the chemical structures, the microstructure and the macroscopic properties. For that, different characterization techniques were used: Fourier transform infrared spectrometry, liquid and solid state nuclear magnetic resonance techniques, X-ray diffraction, small-angle X-ray scattering, smallangle neutron scattering, surface area analysis by Brunauer–Emmett–Teller method, scanning electron microscopy and transmission electron microscopy. Surface roughness and wettability were analyzed by 3D optical profilometry and by contact angle measurements respectively. Bioactivity was evaluated in vitro by immersion of the materials in Kokubos’s simulated body fluid and posterior surface analysis by different techniques as well as supernatant liquid analysis by inductively coupled plasma spectroscopy. Biocompatibility was assessed using MG63 osteoblastic cells. PDMS-SiO2-CaO materials were first prepared using nitrate as a calcium source. To avoid the presence of nitrate residues in the final product due to its potential toxicity, a heat-treatment step (above 400 °C) is required. In order to enhance the thermal stability of the materials subjected to high temperatures titanium was added to the hybrid system, and a material containing calcium, with no traces of nitrate and the preservation of a significant amount of methyl groups was successfully obtained. The difficulty in eliminating all nitrates from bulk PDMS-SiO2-CaO samples obtained by sol-gel synthesis and subsequent heat-treatment created a new goal which was the search for alternative sources of calcium. New calcium sources were evaluated in order to substitute the nitrate and calcium acetate was chosen due to its good solubility in water. Preparation solgel protocols were tested and homogeneous monolithic samples were obtained. Besides their ability to improve the bioactivity, titanium and zirconium influence the structural and microstructural features of the SiO2-TiO2 and SiO2-ZrO2 binary systems, and also of the PDMS-TiO2 and PDMS-ZrO2 systems. Detailed studies with different sol-gel conditions allowed the understanding of the roles of titanium and zirconium as additives in the PDMS-SiO2 system. It was concluded that titanium and zirconium influence the kinetics of the sol-gel process due to their different alkoxide reactivity leading to hybrid xerogels with dissimilar characteristics and morphologies. Titanium isopropoxide, less reactive than zirconium propoxide, was chosen as source of titanium, used as an additive to the system PDMS-SiO2-CaO. Two different sol-gel preparation routes were followed, using the same base composition and calcium acetate as calcium source. Different microstructures with high hydrophobicit were obtained and both proved to be biocompatible after tested with MG63 osteoblastic cells. Finally, the role of strontium (typically known in bioglasses to promote bone formation and reduce bone resorption) was studied in the PDMS-SiO2-CaOTiO2 hybrid system. A biocompatible material, tested with MG63 osteoblastic cells, was obtained with the ability to release strontium within the values reported as suitable for bone tissue regeneration.

Utilização de embriões liofilizados e flocos de Artemia na diversificação nutricional de pós-larvas do camarão marinho Litopenaes vannamei (Boone, 1931)

The objective of the current study was to evaluate the zootechnical performance (survival and growth) of Litopenaeus vannamei post-Iarvae fed an artificial shrimp diet supplemented with Artemia flakes or freeze-dried Artemia embryos. For that purpose, 20 culturing units were individually stocked with 50 shrimp post-Iarvae (average dry weight of 0,3 ± 0,03 mg) at a stocking density of 20 post-larvae per liter, and fed the experimental diets to satiation during 20 days. The experimental design consisted of four diets (T1, T2, T3 and T4) with five repetitions each. For treatments T1, T2 and T3, dietary supplements of 5mg of Artemia flakes (T1), freeze-dried Artemia embryos (T2), and of the commercial shrimp diet (T3) were offered 2 hours after the shrimp were initially fed the commercial shrimp diet. For treatment T4 (control), no additive was offered 2 hours after the initial feeding. Shrimp survival, absolut (GPA) and relative increase in weight (GPR), and specific growth rate (TCR) were used as evaluation criteria. After the experimental period, no significant statistical differences (p>0,05) in survival were observed. Regarding growth, the dietary treatment which used freeze-dried Artemia embryos as an additive (T2) presented the best results for GPA (6,7 ± 0,7 mg). There were no statistical differences within treatments T1, T3 and T4 (p>0,05). AIso, post-larvae fed freeze-dried embryos (T2) showed a relative increase in weight (2241,4%) which differed significantly (p<0,05) from T4(1911,7%) but not from T1 (1801,6%) or T3 (1946,7%). In conclusion, the results of the current study indicate that an artificial shrimp diet supplemented with freeze-dried Artemia embryos fulfils the nutritional requirements of post-larvae L. vannamei and promotes a better growth than diets not supplemented with Artemia flakes

As habilidades sociais em dependentes de álcool: Um estudo exploratório

A vida social de um indivíduo dependente do álcool é na maioria das vezes um factor de risco para continuar ou aumentar o consumo excessivo de bebidas alcoólicas. Um dos grandes fracassos do alcoólico é não cumprir adequadamente um papel social desejado, o que resulta em prejuízos para si mesmo e para os outros. O indivíduo que abusa no consumo, depressa perde a sua reputação junto de colegas, amigos e familiares, o que o deixa mais intolerante à frustração e aumenta o consumo. A mentira toma-se então sua aliada, pois através dela ele vai reduzindo a ansiedade causada pelo fracasso na vida social e que os outros teimam em deixar bem nítido. Identificar os problemas sociais dos quais o indivíduo padece, é fundamental para planear melhor uma estratégia de intervenção, quer seja ela de prevenção, de psicoterapia ou de reabilitação. Os programas de tratamento habitualmente propostos para a abordagem dos problemas derivados do consumo de álcool centram a sua atenção, quase exclusivamente, no comportamento aditivo como guia orientador da intervenção e como indicador objectivo do êxito do próprio programa Mas na maioria dos casos o comportamento aditivo é sim a manifestação mais objectiva de um profundo desajuste entre o sujeito consigo mesmo e com o seu meio ambiente. É por isso, objectivo dos processos de recuperação oferecer-lhe a possibilidade de recuperar a crença na palavra ou aprender o seu valor como meio de comunicação fundamental entre os homens. Para além de possibilitar aos sujeitos dependentes de álcool este valor, importa também incutir nos sujeitos o valor positivo de viver com limites; pois são especialistas em tentar sabotar a acção dos técnicos e em descobrir as suas debilidades para as utilizarem em seu interesse. Importa por isso, que aprendam o valor das leis e a utilidade, para todos, de cumpri-las (Kalina, 2001). Assim, o treino de habilidades sociais constitui uma parte importante dos tratamentos para os sujeitos com problemas de abuso de álcool e drogas. Foi nesse sentido que nos propusemos a identificar o nível de habilidades sociais em pessoas dependentes de álcool. O estudo que desenvolvemos é de carácter exploratório/descritivo, para o qual optámos por utilizar uma metodologia quantitativa. A amostra foi constituída por 229 indivíduos, do sexo masculino, dependentes de álcool, em instituições nacionais de referência na área da alcoologia O instrumento de recolha de dados é constituído por um Questionário de dados sócio demográficos, uma Escala de Habilidades Sociais e uma Escala de Auto-apreciação Pessoal. Constatamos que a amostra constituída por indivíduos dependentes de álcool apresenta uma pontuação média na Escala de Habilidades Sociais de 89.96, equivalente ao percentil 55 na tabela de parametrização de Gismero (2002). Este valor é claramente inferior ao conseguido por qualquer uma das outras amostras analisadas, seja a do estudo preliminar, seja a do estudo comparativo, constituída por indivíduos da população em geral e que conseguiram um percentil 70. ABSTRACT; The social life of a person dependent on alcohol is, most of the time, a risk factor to continue or increase the alcohol excessive consumption. One of the alcoholic failures is the fact that he is unable to perform an adequate social role, to the detriment of himself and others. A person, who abuses alcohol consumption, soon loses his reputation next to his colleagues, friends and relatives, which makes him intolerant of frustration and increases the alcohol consumption. To lie becomes his best ally, because it helps him to reduce the anxiety caused by the failure of his social life, what is promptly pointed out by others. To identify the individual social problems is essential to plan the best intervention strategy. This can be of prevention, psychotherapy or rehabilitation. The treatment programmers, usually proposed to deal with the problems caused by alcohol consumption, focus almost exclusively on the addictive behaviour, as a guide line for the intervention and as an objective indicator of the success of the programme itself. But, in most cases, the addictive behaviour is an objective manifestation of a deep break off of the individual with himself and with his environment. That is why the aim of the recuperation process is to offer the individual the possibility to recover their belief on the word or to learn its value as an essential means of communication for men. Besides getting the message trough, it is also important to make the individuals aware of the positive value of living within limits. These individuals are specialists on trying to sabotage the technicians’ actions, discovering their weaknesses so they can use them on their own behalf. That is why it is so important that they learn the value of rules and the importance of accomplishing them (Kalina, 2001). Therefore, the training of the social skills is an important part of the treatment of individuals with problems of alcohol or dugs addiction. So, we committed ourselves to identifying the level of social skills on people who have an alcohol addiction. The study we developed is exploratory/ descriptive and we chose to use a quantitative methodology. The sample was of 229 male alcohol dependent individuals, staying in national institutes of reference in the area of alcohol abuse and alcoholism. The means to collect data were a social demographic data questionnaire, a scale of social skills and a scale of personal self- assessment. We realized that the sample of alcohol dependent individuals presents an average score in social skills of 89.96, equivalent to a percentile of 55 in the parameterization of Gismero (2002). This is clearly a lower value than the one obtained by any other sample we analyzed, whether in the preliminary study or in the comparative study, constituted by individuals of the common population that achieved a percentile of 70.