Desenvolvimento de pastas de cimento flexíveis para poços de petróleo submetidos à injeção de vapor utilizando látex do tipo SBR

Novel cementing materials formulations containing flexible polymeric admixtures have been studied aiming at improving the mechanical behavior of oil well cement slurries submitted to steam injection. However, research activities in this sector are still under development. The steam injected directly into the well causes casing dilation, which after a reduction in temperature, tends to return to its original dimensions, resulting in crack formation and hydraulic isolation loss of the well, which will result in shortening of well life. In this scenario, the objective of the present study was to evaluate the mechanical behavior of Portland-based slurries containing SBR latex, applied in oil well cementing of wells submitted to steam injection. Were formulated slurries with densities of 1.797 g/cm3 (15.0 lb/Gal) and 1.869 g/cm3 (15.6 lb/Gal), containing admixtures with a latex concentration of 0; 66.88; 133.76; 200.64 and 267.52 L/m3 (0, 0.5, 1.0, 1.5 and 2.0 gpc). Tests including rheology, fluid loss control, thickening time, API compressive strength and splitting tensile strength, beyond steam injection simulation. Microstrutural characteristics of the slurries were also performed (XRD, TG, FTIR and SEM). The results showed that increasing the polymer concentration increased in the rheological properties and fluid loss, and a decrease in the elasticity modulus of the cement slurries. The results obtained showed that the slurries can be applied in cementing operations of oil wells submitted to steam injection.

Otimização e análise mecânica de pastas geopoliméricas para uso em poços sujeitos à injeção cíclica de vapor

Oil wells subjected to cyclic steam injection present important challenges for the development of well cementing systems, mainly due to tensile stresses caused by thermal gradients during its useful life. Cement sheath failures in wells using conventional high compressive strength systems lead to the use of cement systems that are more flexible and/or ductile, with emphasis on Portland cement systems with latex addition. Recent research efforts have presented geopolymeric systems as alternatives. These cementing systems are based on alkaline activation of amorphous aluminosilicates such as metakaolin or fly ash and display advantageous properties such as high compressive strength, fast setting and thermal stability. Basic geopolymeric formulations can be found in the literature, which meet basic oil industry specifications such as rheology, compressive strength and thickening time. In this work, new geopolymeric formulations were developed, based on metakaolin, potassium silicate, potassium hydroxide, silica fume and mineral fiber, using the state of the art in chemical composition, mixture modeling and additivation to optimize the most relevant properties for oil well cementing. Starting from molar ratios considered ideal in the literature (SiO2/Al2O3 = 3.8 e K2O/Al2O3 = 1.0), a study of dry mixtures was performed,based on the compressive packing model, resulting in an optimal volume of 6% for the added solid material. This material (silica fume and mineral fiber) works both as an additional silica source (in the case of silica fume) and as mechanical reinforcement, especially in the case of mineral fiber, which incremented the tensile strength. The first triaxial mechanical study of this class of materials was performed. For comparison, a mechanical study of conventional latex-based cementing systems was also carried out. Regardless of differences in the failure mode (brittle for geopolymers, ductile for latex-based systems), the superior uniaxial compressive strength (37 MPa for the geopolymeric slurry P5 versus 18 MPa for the conventional slurry P2), similar triaxial behavior (friction angle 21° for P5 and P2) and lower stifness (in the elastic region 5.1 GPa for P5 versus 6.8 GPa for P2) of the geopolymeric systems allowed them to withstand a similar amount of mechanical energy (155 kJ/m3 for P5 versus 208 kJ/m3 for P2), noting that geopolymers work in the elastic regime, without the microcracking present in the case of latex-based systems. Therefore, the geopolymers studied on this work must be designed for application in the elastic region to avoid brittle failure. Finally, the tensile strength of geopolymers is originally poor (1.3 MPa for the geopolymeric slurry P3) due to its brittle structure. However, after additivation with mineral fiber, the tensile strength became equivalent to that of latex-based systems (2.3 MPa for P5 and 2.1 MPa for P2). The technical viability of conventional and proposed formulations was evaluated for the whole well life, including stresses due to cyclic steam injection. This analysis was performed using finite element-based simulation software. It was verified that conventional slurries are viable up to 204ºF (400ºC) and geopolymeric slurries are viable above 500ºF (260ºC)

Aditivação de pastas geopoliméricas com tetraborato de sódio e látex não iônico para cimentação de Poços de Petróleo

The development of activities in the oil and gas sector has been promoting the search for materials more adequate to oilwell cementing operation. In the state of Rio Grande do Norte, the cement sheath integrity tend to fail during steam injection operation which is necessary to increase oil recovery in reservoir with heavy oil. Geopolymer is a material that can be used as alternative cement. It has been used in manufacturing of fireproof compounds, construction of structures and for controlling of toxic or radioactive waste. Latex is widely used in Portland cement slurries and its characteristic is the increase of compressive strength of cement slurries. Sodium Tetraborate is used in dental cement as a retarder. The addition of this additive aim to improve the geopolymeric slurries properties for oilwell cementing operation. The slurries studied are constituted of metakaolinite, potassium silicate, potassium hydroxide, non-ionic latex and sodium tetraborate. The properties evaluated were: viscosity, compressive strength, thickening time, density, fluid loss control, at ambient temperature (27 ºC) and at cement specification temperature. The tests were carried out in accordance to the practical recommendations of the norm API RP 10B. The slurries with sodium tetraborate did not change either their rheological properties or their mechanical properties or their density in relation the slurry with no additive. The increase of the concentration of sodium tetraborate increased the water loss at both temperatures studied. The best result obtained with the addition of sodium tetraborate was thickening time, which was tripled. The addition of latex in the slurries studied diminished their rheological properties and their density, however, at ambient temperature, it increased their compressive strength and it functioned as an accelerator. The increase of latex concentration increased the presence of water and then diminished the density of the slurries and increased the water loss. From the results obtained, it was concluded that sodium tetraborate and non-ionic latex are promising additives for geopolymer slurries to be used in oilwell cementing operation

Leaf anatomy of rubber-tree clones

A seringueira é uma planta de fácil reconhecimento por ser lenhosa, de porte mediano a grande, que apresenta um padrão característico de desfolha e reenfolhamento e, sobretudo, pela produção de látex. O objetivo do trabalho foi efetuar um estudo anatômico e morfológico foliar, comparando os clones RRIM 600 e GT 1 de seringueira &91;Hevea brasiliensis (Wild. ex Adr. de Juss.) Muell.- Arg&93;, desenvolvidos sob as mesmas condições edáficas e climáticas, para obtenção de informações que possam fornecer subsídios para correlações com dados fisiológicos e também diferenciar os clones em relação ao conteúdo de fibras, espessamento de tecidos do parênquima paliçádico e do parênquima lacunoso, caracterização anatômica do pecíolo, número e tamanho de estômatos e fornecer dados referentes a morfologia foliolar. Foram realizadas secções transversais na região do mesófilo, nervura central e pecíolo, seguindo-se os métodos usuais de preparação de lâminas permanentes. Foram realizadas análises biométricas de extensões de tecidos dos parênquimas paliçádico e lacunoso e contagem do número de células do parênquima lacunoso. Paralelamente foram realizadas análises biométricas para aferições de estômatos. Não houve diferenças para a altura das células epidérmicas, altura e número de camadas do parênquima lacunoso e para o comprimento e para a maior largura do limbo foliolar. Porém houve variação para a espessura das células do parênquima paliçádico, sendo que GT 1 apresentou maior espessura em relação a RRIM 600. GT1 apresentou maior número de estômatos em relação a RRIM 600, porém com menor tamanho. GT1 apresentou maior diâmetro da nervura central da folha e do pecíolo e maior quantidade de fibras de esclerênquima que RRIM 600.

Perfil eletroforético do proteinograma sérico de eqüinos com obstrução experimental do cólon menor

Avaliaram-se as alterações do proteinograma sérico de eqüinos submetidos à isquemia e reperfusão do cólon menor por distensão intraluminal. Foram utilizados 10 animais submetidos à laparotomia pelo flanco, em posição quadrupedal, para a indução de obstrução no cólon menor durante um período de quatro horas. Cinco animais foram instrumentados, mas sem distensão (grupo controle - G1). em cinco outros animais, foi realizada isquemia mural por distensão do cólon menor via manguito inflado com 40mmHg (grupo distendido - G2). Foram colhidas amostras de sangue antes da intervenção cirúrgica (M1), com 4 horas da colocação do manguito (M2) e com 3 horas (M3) e 12 horas (M4) de reperfusão. Após centrifugação e fracionamento das amostras, as proteínas de fase aguda foram separadas por eletroforese em gel de poliacrilamida contendo SDS-PAGE, e suas concentrações determinadas por densitometria computadorizada. Foram encontradas 19 proteínas no fracionamento eletroforético, com peso molecular variando de 185.000 a 14.000 Daltons (Da). Os pesos moleculares encontrados, correspondentes às proteínas mais conhecidas, foram ceruloplasmina, 130.000 Da; proteína C-reativa, 122.000 Da; transferrina, 85.000 Da; α1-antitripsina, 61.000 Da; haptoglobina, 47.000 Da; e glicoproteína ácida, 40.000 Da. Os resultados mostram que proteínas de fase aguda se alteram após o trauma cirúrgico.

Peritoneal fluid changes in horses subjected to small colon distension

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Ocorrência de Bacillus cereus em leite integral e capacidade enterotoxigênica das cepas isoladas

Pesquisaram-se a presença de Bacillus cereus e a produção de enterotoxinas produzidas por esses microrganismos em 120 amostras de diversos tipos de leite. Bacillus cereus foi isolado e identificado em 22 (73,3%), 15 (50,0%), 29 (96,7%) e quatro (13,3%) amostras de leite em pó, cru, pasteurizado e UAT (longa vida), respectivamente. Para a detecção de enterotoxinas pela técnica da alça ligada de coelho, foram positivos, respectivamente, três (13,6%), um (7,1%) e 10 (35,7%) microrganismos isolados das amostras de leite em pó, leite cru e leite pasteurizado. Pelo teste de aumento de permeabilidade vascular, dois (9,1%), um (7,1%), um (3,6%) e um (4,0%) microrganismos isolados de leite em pó, cru, pasteurizado e UAT apresentaram-se enterotoxigênicos, respectivamente. O uso da técnica de aglutinação passiva em látex demonstrou a produção da toxina diarréica por três (33,3%), sete (63,6%), quatro (30,8%) e oito (80,0%) microrganismos isolados, respectivamente, de leite em pó, cru, pasteurizado e UAT. Os resultados indicam um risco potencial, podendo colocar em risco a saúde dos consumidores desses produtos.

Ramos do arco aórtico de bubalinos

Os ramos do arco aórtico (Arcus aortae) em bubalinos foram investigados neste trabalho. Assim, foram dissecadas as artérias oriundas desse arco previamente injetadas com solução corada de látex Neoprene 650â (Du Pont do Brasil S.A.) em 20 fetos dessa espécie, machos e fêmeas com idades entre 4 e 8 meses de gestação. em 80% dos casos, observou-se que o tronco braquiocefálico (Truncus brachiocephalicus) emite a artéria subclávia (Arteria subclavia) esquerda, artérias carótidas comuns (Arteria carotis communis) esquerda e direita, sem caracterizar tronco bicarotídeo (Truncus bicaroticus), e a artéria subclávia direita. As artérias subclávias direita e esquerda originam em comum o tronco costocervical (Truncus costocervicalis), a artéria cervical superficial (Arteria cervicalis superficialis), artérias axilares (Arteria axillaris) e artéria torácica interna (Arteria thoracica interna). em 20% dos casos, o tronco braquiocefálico origina a artéria subclávia esquerda em comum ao tronco costocervical esquerdo; em seguida, emite a artéria carótida comum esquerda e termina trifurcando-se em artéria carótida comum direita, artéria subclávia direita e tronco costocervical direito, sendo que as artérias subclávias direita e esquerda têm origem comum com as artérias cervical superficial, axilar e torácica interna, com a presença do tronco bicarotídeo, característico dos bovinos.

Origem das artérias celíaca e mesentérica cranial em bubalinos (Bubalus bubalis, L. 1758)

Com o intuito de conhecer melhor o sistema arterial nesta espécie, descrevemos a origem das artérias celíaca e mesentérica cranial dos bubalinos. Utilizamos 30 fetos e 1 animal adulto. Os fetos variavam de 4 a 8 meses de idade e tiveram seus vasos injetados com solução de látex - Neoprene, tiveram seus vasos dissecados, e um animal adulto, que teve seus vasos dissecados no local de abate. Observamos que as artérias celíaca e mesentérica cranial originavam-se da porção torácica da aorta em todos os casos, estando isoladas em 90,33% deles e em tronco comum (tronco celíaco mesentérico) em 9,67% dos casos.

Descrição anátomo-topográfica do coração da paca (Agouti paca)

Background: The domestic animals heart is a conical hollow viscera, surrounded by pericardium, laterally compressed, accompanying the thorax shape. Atriums constituted the heart basis and their auricles partially bound the initial portion of the aorta and pulmonary trunk. In mammals, heart is kept suspended in the thoracic cavity and the pericardic sac is fixed dorsally by great veins and arteries roots, and ventrally fixed to the sternum, although its fixation to the diaphragm varies among species. This paper aimed to describe morphological aspects of the heart of the paca, the second biggest Brazilian rodent.Materials, Methods & Results: There were used 12 hearts of adult pacas for this study, obtained from the UNESP, Jaboticabal, SP, which died due fights or anesthesia during bandages or radiograph exams. The thoracic aorta was filled with colored latex and the animal was set in a 10% formaldehyde solution for at least 72 hours. The thoracic cavity was dissected and hearts individualized and measured with a paquimeter, lateromedially, craniocaudally and dorsoventrally. The paca heart is placed between the first and fifth intercostal space (ICS), in a craniocaudal oblique position; its basis is craniodorsally positioned, on the middle third between the first and second ICS and its apex is located near the sternodiaphragmatic joint, on the fifth ICS, tilted to the left antimere. The heart is surrounded by pericardium, which from ventrocaudally is originated the sternopericardic ligament, that continues as phrenopericardic ligament. At the heart basis, the rising of the pulmonary trunk was observed and the conus arteriosus formed a typical projection. The aorta also rised from the heart basis and its arch, which was caudally curved, crossed dorsally the pulmonary trunk; the right cranial and caudal cava veins drained to the right atrium. There is a left cranial cava vein, which surrounded the left atrium and joined the right caudal cava vein on the right atrium. The azygos vein joins the right cranial cava vein and four pulmonary veins drained to the left atrium. At palpation, a hard structure on the rising of the aorta was observed, similarly to a cartilaginous tissue, which would be part of the cardiac skeleton. The left and right coronary arteries were observed in all hearts.Discussion: The paca heart is anatomica and topographically similar to those of domestic mammals, differing from them for being placed one intercostal space more cranial and due to the presence of two cranial cava veins, the left and the right ones, besides the presence of the caudal cava vein. This vascular description is similar to that of small rodents, as rats and mice. In paca heart, the sinus venous, the terminal crest, the oval fossa, the atrioventricular valvae, the papillary muscles and tendinous cords, besides smooth atriums and auricles covered by pectinate muscles, were observed. The sternopericardic ligament, which is dorsally elongated as phrenopericardic ligament, is similar to the one present in humans, pigs, castors, and different from the one observed in carnivorous, that presents the phrenopericardic ligament and from the one of horses and ruminants, which present the sternopericardic ligament.

Virulence properties and antimicrobial susceptibility of Shiga toxin-producing Escherichia coli strains isolated from healthy cattle from Parana State, Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Envelhecer entre pássaros e anjos: um estudo etnográfico sobre o processo saúde doença do idoso no contexto familiar

Study, a descriptive-like one, is guided by ethnographic principles which have analyzed the elderly within the familiar context in his/her process of health and aging, in the neighborhood called Felipe Camarão, located in the western administrative region of Natal, RN, a Northeastern city of Brazil. The participants are elders aging 61 to 84 years old, living in this referring neighborhood, whose majority is constituted of migrants from the rural region of the state of the RN, retired, including widows, widowers and married couples, with low school-educational degree. For the information gathering it was utilized a semi-structured interview, the participant observation and the field diary, being put into effect, in majority, in the houses and in the Family Health Unit, in a period between March and October of 2006. For the results discussion it was utilized an analysis of thematic content and the program ALCESTE (In Portuguese, Análise Léxica por Contexto de um Conjunto de Segmentos de Texto or Lexical Analysis by Context of a Set of Text Segments), which through have emerged two corpus: the corpus I, Family and the elderly, and corpus II, The elderly and the aging within society. The analysis of the results has permitted to conclude that the family, also used by the public policies as a strategy of their practices in health, it is a necessary base support for the elderly citizen in his/her process of aging and of health. The elders familiar contexts have allowed this study to identify the existence of minimal social conditions of life, of new rearrangements of the current families by means of the plurigenerational acquaintanceship and the active presence of the elderly woman as a maintainer of this family; also by means of conflicted relationships among one another but in a bearable level of acquaintanceship. Different conceptions about the aging and the elderly generate disagreement and divergency however the family support and help for the solving of these problems and the attention to health are proceeding from the family components. However, it is noticed that loneliness is something present in these elder s everyday lives. About the attention to health, in a basic level of it, it was noticed that there are still a lot of gaps, mainly concerning promotional and preventing actions, deserving a higher sensitization and effort by the local health institutions

Análise tecnológica sobre os aspectos ambientais de empreendimentos hoteleiros da Praia de Ponta Negra Natal/RN: um modelo de sistema de gestão ambiental

The present work aimed the elaboration of an environmental study focused on the hotel sector in order to present an analysis of the environmental aspects of Ponta Negra Beach, in Natal, RN, Brazil and also the aspects of the small and medium hotels existing in this area. By means of this work, it is possible to elaborate a model of a simplified System of Environmental Management which can attend to the exigencies required by NBR ISO 14001: 2004, as well as to present economical viability and possibility to be implemented in a way that hotels may converge to the sustainable environmental development of the tourism in Ponta Negra Beach. The research methodology presents itself divided into three items: execution of the environmental characterization of Ponta Negra Beach, by way of technical visits and interpretation of satellite images and cartograms of the main environmental characteristics of the region; execution of the work already made concerning the development, application and interpretation of the evaluation of the environmental aspects of each hotel, considering the hotels and the period of data collection, these used in evaluation, research instrument and a description of the procedure utilized for the analysis of the collected data and the utilized methodology for the elaboration of a model of a simplified System of Environmental Management. In a general way, it has been concluded that the practices executed by hotels in Ponta Negra Beach are impact-like and harmful to the environment. The simple implementation of analysis procedures and control of the environmental aspects could suggestively contribute to the reduction of environmental impacts promoted by the hotel section at this beach and in the nearby areas. It had been noticed that the study contributed to the sensitization of managers concerning the environmental problems since, in many other times, the detected problem was, in fact, the non-acquaintance about the environmental aspects and impacts from those hotels administrators, because of the lack of surveys and studies about the theme. It had also been noticed the arousing of a possible environmental attitude from some managers

Gestão ambiental e competitividade: um estudo sobre os fatores que afetam a decisão de compra de produtos orgânicos na cidade de Teresina-PI

The organic products represent one of the main trends of alimentary consumption in the new century. In Brazil, the answer is already well representative which it becomes the country, as a great consuming and exporting market of products of LVF type. The objective of this research was to investigate the factors capable to influence the food consumer in its purchase decision of organic products in the supermarkets of Teresina, capital of Piauí State. The methodology was exploratory and descriptive, using survey, with closed and opened questions in 542 interviewed. The questionnaire was based on projected scales to evaluate the factors that can influence the purchase decision of organic products, whose variable had been grouped in the following groups: behavior, knowledge, interest, competitiveness, importance, barrier and profile. The used statistical techniques were descriptive analysis and multiple regression analysis. The results demonstrate interest of the population in paying more for the organic product, due to better quality of life, however it lacks to one better spreading and greater sensitization to attract these consumers. Some recommendations and proposals are presented after the results, as suggestions for future research

Desenvolvimento de material compósito a base de raspa de pneu e látex para isolamento térmico

The process of recycling has been stimulated by the markets for several reasons, mainly on economical and environmental. Several products have been developed from recycled materials that already exist as well as several residues have been studied in different forms of applications. The greater majority of the applications for thermal insulation in the domestic, commercial and industrial systems have been elaborated in the temperature ranges between low to medium reaching up to 180oC. Many materials such as glass wool, rock wool, polystyrene are being used which are aggressive to the environment. Such materials in spite of the effectiveness in the retention of heat flow, they cost more and when discarded take several years to be absorbed by the nature. This way, in order to adapt to a world politics concerning the preservation of the environment, the present study was intended to develop a material composed of natural/biodegradable materials and industrial residues. The development of such a product in the form of a composite material based on tyre scrapes and latex for thermal insulation is presented in this research work. Thermal and physical properties of the tire scrapes as well as latex were studied in order to use them as raw materials for the manufacture of the intended composite to be applied as a thermal insulator in hot and cold systems varying between 0ºC and 200oC, respectively. Composite blankets were manufactured manually, in weight proportions of 1:1 (50:50%); 1:2 (33:67%) and 2:1 (67:33%) (tire scrapes: latex) respectively. Physical, mechanical and thermal properties of the composites were analyzed to obtain data about the viability of using the composite as a thermal insulator. The analyses carried out were based on standards ABNT, ASTM and UL. The maximum temperature obtained for the composite as a thermal insulator was 200ºC, which meets the range of applications that could be used as a thermal insulator in domestic as well as industrial purposes. The experimental results prove that the composite can be used as a thermal insulator on heated or cooled surface