Validação de uma metodologia de ensaio de resistência ao cisalhamento para avaliação da aderência de interfaces revestimento metálico-bainha de cimento aplicada a poços de petróleo

Improving the adherence between oilwell metallic casing and cement sheath potentially decrease the number of corrective actions present/y necessary for Northeastern wells submitted to steam injection. In addition to the direct costs involved in the corrective operations, the economic impact of the failure of the primary cementing aIso includes the loss in the production of the well. The adherence between casing and cement is current/y evaluated by a simple shear tests non standardized by the American Petroleum Institute (API). Therefore, the objective of the present is to propose and evaluate a standardized method to assess the adherence of oilwell metallic casing to cement sheath. To that end, a section of a cemented oilwell was simulated and used to test the effect of different parameters on the shear stress of the system. Surface roughness and different cement compositions submitted or not to thermal cycling were evaluated. The results revealed that the test geometry and parameters proposed yielded different values for the shear stress of the system, corresponding to different adherent conditions between metallic casing and cement sheath

Crescimento radicular de plântulas de milho afetado pela resistência do solo à penetração

A resistência do solo à penetração é relacionada com a textura, compactação e umidade do solo. No presente trabalho se estudou o efeito da interação desses fatores sobre o crescimento de raízes de milho. Materiais de solo com 22, 30, 34, 41 e 48% de argila foram acondicionados em tubos de PVC de 10 cm com 4,3 cm de diâmetro interno, nas densidades globais de 1,07, 1,18, 1,36 e 1,53 g cm-3, em três tensões de água: -0,034, -0,106 e -0,640 MPa. Plântulas de milho foram cultivadas nos tubos por 48 horas. Quando a densidade do solo é baixa, a textura tem papel preponderante no crescimento radicular. Esse efeito é menor à medida que aumenta a densidade global. O aumento da resistência do solo à penetração causa diminuição no comprimento e número de raízes seminais adventícias; a raiz seminal primária mostra menor capacidade de penetração do que as raízes seminais adventícias. Resistências do solo à penetração da ordem de 1,3 MPa reduzem à metade o crescimento das raízes seminais adventícias do milho.

Longevidade de sementes de camu-camu submetidas a diferentes ambientes e formas de conservação

O camu-camu (Myrciaria dubia (H.B.K.) McVaugh) produz fruto com grande potencial para extração de ácido ascórbico, que apresenta relevante importância econômica e social, com inúmeras aplicações industriais. O objetivo deste trabalho foi avaliar o efeito de diferentes formas de conservação e ambientes de armazenamento, sobre a manutenção da viabilidade das sementes. O delineamento experimental inteiramente casualizado, utilizando parcelas subsubdivididas, onde os fatores foram: ambiente de armazenamento (ao ar livre, em água, em câmara a 5 e a 10 ºC), forma de conservação (sementes com polpa - CP, sementes sem polpa - SP e sementes lavadas e tratadas - LT) e período de armazenamento (0; 2; 4 e 6 meses). O critério de avaliação adotado foi a protrusão da raiz primária. As sementes armazenadas em água, nas formas SP e LT, apresentaram germinação maior que 90%. As sementes nas formas CP e LT, armazenadas a 5 e a 10 ºC, tiveram germinação acima de 89%. O armazenamento em água e ao ar livre não afetou a germinação, podendo as sementes serem armazenadas durante o período de seis e quatro meses, respectivamente. As sementes CP, armazenadas em água, tiveram menor tempo médio para germinação. O índice de velocidade de germinação aumentou com o período de armazenamento e foi maior nas sementes armazenadas na água em todos os períodos. As sementes com polpa apresentaram menor índice de velocidade de germinação em todo o período de armazenamento avaliado.

Comportamento germinativo de sementes de leiteiro (Peschiera fuchsiaefolia): efeito da temperatura e luz

O leiteiro é uma planta daninha que ocorre em pastagens, de importância crescente no Brasil e que reproduz-se por sementes. Com o objetivo de conhecer o comportamento germinativo dessa espécie, as sementes foram colocadas para germinar sobre papel, em temperaturas constantes de 15, 20, 25, 30, 35 e 40ºC, sem ou com luz (78 µmol s-1m-2/8h). Para a avaliação dos tratamentos, foram contabilizadas, semanalmente, o número de sementes germinadas (G), considerando-se a protrusão de 1cm de raiz primária, até que cessasse a germinação em todos os tratamentos (63 dias após a semeadura) e, determinou-se o índice de velocidade de germinação (IVG). Após esse período, as sementesforam transferidas para a temperatura de 30ºC com luz (condição favorável detectada na etapa anterior) e realizou-se contagem semanal até que a germinação cessasse novamente, em todos os tratamentos (91 dias após a semeadura), quando foram contabilizadas as sementes mortas (M) e as sementes quiescentes (Q). Os resultados indicaram que as sementes de leiteiro foram indiferentes à luz. A temperatura ótima de germinação para a espécie situou-se entre 25 e 30ºC (G=85%, M=15% e IVG=34). Nas temperaturas extremas de 15ºC (G=0%; Q=78%; M=22%) e 40 ºC (G=0%; Q=0% e M=100%) não houve a germinação das sementes.

Comparação entre métodos para a avaliação do vigor de lotes de sementes de couve-brócolos (Brassica oleracea L. var. italica Plenk)

Os testes de vigor e o teste de germinação são componentes essenciais no controle de qualidade das empresas de produção de sementes. Com o objetivo de verificar a eficiência de diferentes testes de vigor e de variações de suas metodologias na avaliação da qualidade de sementes de couve-brócolos visando diferenciação de lotes e previsão de emergência em bandeja, cinco lotes de sementes do híbrido Flórida foram submetidos aos seguintes testes: germinação; primeira contagem de germinação; emissão de raiz primária (após 48, 56, 72, 80 e 96 h após a instalação do teste de germinação); emergência de plântulas em substrato; envelhecimento acelerado com água (1g de sementes mantidas a 41ºC por 48 e 72 h a 100%UR); envelhecimento acelerado com solução saturada de sal (mesmo procedimento do item anterior, porém usando solução de NaCl, 40% e 76%UR); condutividade elétrica (50 sementes em 25 mL de água destilada a 25ºC e leituras após 2, 4, 6, 8 e 24 h). Todos os testes apresentaram correlação significativa com a porcentagem de emergência de plântulas em substrato, a 1% de probabilidade. Os testes de envelhecimento acelerado com solução saturada de sal por 48 h e de condutividade elétrica após 8 e 24 h de embebição foram eficientes e tiveram resultados semelhantes aos da emergência em substrato. Os testes da primeira contagem de germinação, emissão da raiz primária após 56 h e envelhecimento acelerado com solução saturada de sal por 72 h, apresentaram-se mais eficientes que a emergência de plântulas em substrato na diferenciação do vigor dos lotes.

Avaliação do vigor de sementes peliculizadas de tomate

Com o objetivo de verificar a eficiência de diferentes testes de vigor na avaliação da qualidade de sementes peliculizadas de tomate, cinco lotes do híbrido Saladinha foram submetidos aos seguintes testes: germinação; primeira contagem de germinação; emissão de raiz primária (determinada 56, 72, 80 e 96 horas após a instalação do teste de germinação); emergência de plântulas em substrato tipo Plantmax em bandeja de poliestireno; envelhecimento acelerado com água (1g de sementes mantidas a 41ºC por 48 e 72 horas a 100%UR); envelhecimento acelerado com solução saturada de sal (mesmo procedimento do item anterior mas usando solução de NaCl 40% e 76%UR); condutividade elétrica (50 sementes em 25 ml de água destilada a 25ºC e leituras após 2, 4, 6, 8 e 24 horas. ). O teste de germinação, a determinação da emissão de raiz primária (períodos de 56, 72 e 96 horas após a semeadura) e o teste de condutividade elétrica (2, 4, 6 e 8 horas de embebição) apresentaram correlação significativa com a porcentagem de emergência de plântulas em substrato. O teste de condutividade elétrica por períodos de 2 a 8 horas de embebição foi eficiente e teve resultados semelhantes aos da emergência em substrato. A determinação da emissão de raiz primária (após 56, 72 e 96 horas) mostrou-se promissora para a avaliação do vigor de sementes peliculizadas de tomate.

Dinâmica de Sedimentação de Lodo em Lagoas de Estabilização

Stabilization ponds are an effective sewage treatment alternative for the climatic conditions prevailing in Brazil. In the present work, a primary facultative pond was studied, in the city of Natal, Rio Grande do Norte, Northeast Brazil. The aim of this study was to evaluate the sedimentation dynamics in the facultative pond. The pond was divided in three section or zones along its length starting from the inlet end namely A1, A2 and A3. The research was accomplished in three phases. In the first the mapping of the sludge layer was done, sludge core samples were also collected for analysis for total, fixed and volatile solids and the depth of the sludge layer was determined using a portable echo sounder. In the second solids sedimentation rates were measured using traps placed in the inlet and outlet zones and in the third phase resuspension sludge was evaluate using a tracer. The amount accumulated sludge since the start operation was 13.583 m3. The sedimentation constant averages changed between 0.93 to 2.94 and 3.90 to 5.80 for the depths of 0.5 and 1.0 m respectively. The relationship between volatile and fixed solids (SV/SF) increased along the pond. The removal efficiencies were 52.12%, 36.09%, and 37.50% for BOD, COD and SS, respectively. The sludge accumulation model proposed had a good adjustment with 0.17 m3/hab.year rate. The results presented here demonstrated that the wind had a direct influence on the sedimentation of solids in this pond affecting the efficiency and sludge accumulation

Evolução da biodegradabilidade da matéria orgânica em um sistema de lagoas de estabilização

Waste stabilization ponds (WSP) have been widely used for sewage treatment in hot climate regions because they are economic and environmentally sustainable. In the present study a WSP complex comprising a primary facultative pond (PFP) followed by two maturation ponds (MP-1 and MP-2) was studied, in the city of Natal-RN. The main objective was to study the bio-degradability of organic matter through the determination of the kinetic constant k throughout the system. The work was carried out in two phases. In the first, the variability in BOD, COD and TOC concentrations and an analysis of the relations between these parameters, in the influent raw sewage, pond effluents and in specific areas inside the ponds was studied. In the second stage, the decay rate for organic matter (k) was determined throughout the system based on BOD tests on the influent sewage, pond effluents and water column samples taken from fixed locations within the ponds, using the mathematical methods of Least Squares and the Thomas equation. Subsequently k was estimated as a function of a hydrodynamic model determined from the dispersion number (d), using empirical methods and a Partial Hydrodynamic Evaluation (PHE), obtained from tracer studies in a section of the primary facultative pond corresponding to 10% of its total length. The concentrations of biodegradable organic matter, measured as BOD and COD, gradually reduced through the series of ponds, giving overall removal efficiencies of 71.95% for BOD and of 52.45% for COD. Determining the values for k, in the influent and effluent samples of the ponds using the mathematical method of Least Squares, gave the following values respectively: primary facultative pond (0,23 day-1 and 0,09 day-1), maturation 1 (0,04 day-1 and 0,03 day-1) and maturation 2 (0,03 day-1 and 0,08 day-1). When using the Thomas method, the values of k in the influents and effluents of the ponds were: primary facultative pond (0,17 day-1 and 0,07 day-1), maturation 1 (0,02 day-1 and 0,01 day-1) and maturation 2 (0,01 day-1 and 0,02 day-1). From the Partial Hydrodynamic Evaluation, in the first section of the facultative pond corresponding to 10% of its total length, it can be concluded from the dispersion number obtained of d = 0.04, that the hydraulic regime is one of dispersed flow with a kinetic constant value of 0.20 day-1

Avaliação da flotação por ar dissolvido no polimento de efluentes de lagoa de estabilização

Experience in the use of stabilization ponds shows that this is a system with low cost, easy operation and maintenance and suitable for tropical countries. One of its disadvantages is due to high concentrations of suspended solids, mainly due to algal biomass in the effluents. Accordingly, the dissolved air flotation has been shown to be an efficient post-treatment technology. However, the efficiency of this process is related to coagulation and flocculation steps, as well as the adjustment of the involved variables in the process. The objective of this work was to evaluate the algae removal efficiency from wastewater stabilization ponds and the influence of the factors involved in the process using dissolved air flotation. For this, we used primary facultative and maturation effluents of ETE Ponta Negra in Natal. We did tests of coagulation, flocculation and flotation with the samples, using the equipment flotatest. In this process were tested coagulants aluminum sulfate and ferric chloride, and varied the factors pH, coagulant concentration, polymer concentration and rate of recirculation. At the end of the experiments were analyzed turbidity, suspended solids, color, COD and chlorophyll "a". These results were submitted to descriptive statistics to verify the efficiency of the process in general, and regression analysis to identify models that describe the process and demonstrate the factors that have greater influence on flotation. After step methodology, high values were found removal efficiency of suspended solids, reaching values greater than 90% in the best cases. It was concluded that flotation is more efficient in the facultative pond effluent using ferric chloride, and the variability of algae may negatively influence the process. Regression analyzes showed that pH is the most influential variable in the coagulation-flocculation-flotation, and its optimal value among the tested is 5.5 for both coagulants

Remoção de Microalgas de efluentes de lagoas de estabilização utilizando biofiltro

This research evaluated the microalgae removal produced in a stabilization pond system using biofilters as post-treatment, besides characterizing the effluents of stabilization ponds and filters in relation to concentrations of algal biomass (chlorophyll a and suspended solids), organic matter (BOD and COD), total phosphorus, orthophosphate, pH and dissolved oxygen, and tried to correlate physicochemical parameters with chlorophyll "a". It was held at the Ponta Negra ETE which is constituted by three stabilization ponds, with a primary facultative pond and two of maturation. For the algae removal were used two submerged bio-filters: the filter FPF (Facultative Pond Filter), fed with facultative pond effluent; and the filter MPF (Maturation Pond Filter), fed with second maturation pond effluent. The filling material of both filters was predominantly gravel no. 2, although it contains portions of gravel no. 1 and no. 3. The filters operating conditions were bad, they were nearly 10 years without maintenance, without cleaning or removal of sludge since the time of its construction, and part of the filling material may be obstruct. Despite poor operating conditions were obtained satisfactory results, in level of posttreatment. Removal efficiencies in relation to BOD and COD were 7 and 25% in FPF and 9 and 19% and in MPF, respectively. In relation to TSS efficiencies in MPF and FPF were 37 and 20%, respectively. As for the chlorophyll "a" removal, the FPF efficiency was 44% and the MPF was 40%. There was 50% of consumption of dissolved oxygen, on average, within the filters. Two profiles were performed in the filters, and it was possible to conclude that variations throughout the day were not statistically significant, and that, regardless of the time of collection, they would have the same representation comparing to the time of data collection (7 am) and the daily average, although individual variations throughout the day have been shown to be significant. Another important observation is that the correlations between Chlorophyll a and TSS were bigger and more significant in the effluent of the filters than in the effluent of the ponds

Os reservatórios eutrofizados da região tropical semiárida atuam como emissores ou como sequestradores de dióxido de carbono?

The aquatic ecosystems can play a role as carbon-dioxide-source or carbon-dioxide-sink systems due to the high predominance of heterotrophic or autotrophic metabolism. The primary production can strongly affect the carbon balance (CO2) through the consumption of carbon dioxide in the photosynthesis, especially in eutrophic environment, acting as a carbon sink. The present study tested the hypothesis that the eutrophic reservoirs in tropical semi-arid region are carbon dioxide-sink systems due to the high primary productivity presented in these systems. Five Brazilian reservoirs from the semi-arid in the northeast region were monitored monthly during four years (2010 to 2013) with a prolonged drought event identified during the study. The results showed an increasing level of eutrophication over the period of prolonged drought, with the predominance of autotrophy. Significant negative correlations were observed between the partial pressure of CO2 (pCO2) (p<0,001) and chlorophyll-a in the Boqueirão, Passagem das Traíras, Dourado and Gargalheiras reservoirs, showing a pattern of the carbon dioxide-sink systems. However, this pattern was not found in Cruzeta reservoir. In summary, in the tropical semi-arid region, hydrological and morphometric variables can lead to different behaviors of the water-supply reservoirs on the carbon metabolism. The eutrophic reservoirs evaluated showed a negative relationship between pCO2 and Chl-a, which suggests that these water bodies show an autotrophic metabolism and behave as carbon dioxide- sink systems

Avaliação da eficiência da remoção de matéria orgânica e microbiológica de três sistemas de lagoas de estabilização em série na Grande Natal-RN: Beira Rio, Jardim Lola I e Jardim Lola II

Waste stabilization ponds are the main technology in use for domestic sewage treatment in Rio Grande do Norte State (RN), northeast Brazil. The are around 80 systems, constructed mainly by municipal city halls, being series comprised by a primary facultative pond followed by two maturation ponds the most used configuration. Due to problems related with the production and destination of sludge and generation of bad odors, the designers have avoided the use of anaerobic lagoons. The majority of systems are rarely monitored to verify their efficiencies and to get new project parameters for future designing. This work has as purpose to make a diagnosis of efficiency of three series of waste stabilization pond series (WSPS) of Jardim Lola 1, Jardim Lola 2 and Beira Rio, located in the North Zone of the city of the Natal/RN, treating domestic raw sewage, on the removal of organic matter and thermotolerant coliform, comparing the operational conditions of the systems this inside of the bands foreseen in the project, through parameters BOD5, QOD, thermotolerant coliforms, dissolved oxygen, pH, temperature, ammoniac nitrogen, total and suspended solids. The work was carried through in the WSPS, all constituted by a primary facultative pond followed by two maturation ponds. Socioeconomic characteristics of population are predominantly low and all the plants are very near of the contributing basins. The series were monitored from of May the November of 2002, totalizing 20 collections of grab samples of raw sewage and ponds effluents between 8:00 and 9:50 h. The main aspect to be detached by the results was the great concentration of organic matter (BOD and COD) and microorganisms the raw sewage which were around two times more concentrated than those values foreseen one in project. Considering all series the highest removals of organic matter were observed in system Beira Rio (84 and 78% of BOD and COD, respectively), which presented high hydraulic detention time (TDH = 89 days). On the other hand, Jardim Lola 1 and Jardim Lola 2 presented a much lower values of HDT (36 days and 18 days respectively) and their removals of BOD and COD were the same (76% and 60%, respectively). The Beira Rio WSPS, was the most efficient verified in relation to solids and ammonia, proving the great influence of the operational variables such as HDT and applied surface organic loadings on the performance of pond series. Although the treatment plants have reached efficiencies of thermotolerant coliforms around 99,999%, the concentrations in the final effluent can be considered very high for launching in aquatic bodies, particularly those produced by Jardim Lola 1 and Jardim Lola 2 series

Diagnóstico operacional de lagoas de estabilização

This work intends to develop an approach based through scientific criteria in the operational diagnosis of ponds of stabilization, starting from analyses accomplished in loco and in laboratory of 78 systems of sewer treatment through ponds of stabilization in the State of Rio Grande do Norte. The objectives of the research are: to map, to evaluate and to diagnose the operational acting of the ponds of stabilization of the state of Rio Grande do Norte, through visits in loco and analyses laboratory; to build a SIG, through the map rain, locate the points of releases of sewages of the systems of existent ponds in Rio Grande do Norte, as well as operational data and his/her respective efficiency diagnosis in the removal of BOD and Coliforms Termotolerantes; to evaluate, in real scale, three systems of ponds of stabilization of RN in the operational efficiency for the parameters BOD5, COD, pH, Temperature, OD and Coliforms Termotolerantes. Of 78 ETEs of appraised RN just, 9% or 7 had maximum concepts in what concerns the removal of BOD and Coliforms Termotolerantes and 41% or 32, they had the worst concepts in term of operational efficiency. The flowing concentrations ETEs of RN of BOD and Coliforms were of 410mg/L and 2,50x107UFC/100ml, the predominant configuration is of the type F1+M1+M2, the relationship BOD/COD revealed for the sewer tributary characteristic biodegradable high. For the study of case of 3 ETEs, the best operational efficiencies in decreasing order were: Cidade (Municipal district), it Roça (State) and São Miguel (SAAE). The removals of final BOD were 51,6mg/L; 108,27mg/L and 62,6mg/L, tends efficiency of 82%; 74% and 81%. In term of coliforms removal in the final effluentes were 1,90x103UFC/100ml; 1,50x104UFC/100ml and 3,10x104UFC/100ml, tends efficiencies of 99,99%; 99,95% and 99,90%. In what it concerns the practice of agricultural reúso of cultures consumed raw, none of 3 ETEs assisted the parameters of the Resolution CONAMA 357/05, for other reúso practices, all assisted the categories B and C of OMS. For release in body receiving ETE Cidade just, they assist the demands of the resolution of CONAMA 357/05, by study of purification solemnity of the receiving body. The maintenance lack and operation; exclusive operator in ETEs and operation knowledge was the contributory factors for the operational fall in appraised ETEs of RN

Elaboração de atividades didáticas para o ensino de matemática a partir de livros antigos: o exemplo do leçons élémentaires de Lagrange

De nombreuses études sur l`utilisation pédagogique de l`histoire des mathématiques viennent a identifier les arguments qui sous-tiennent ces actions éducatives comme une façon d`aborder les mathématiques scolaires afin de mener les élèves à un apprentissage réflexif et significatif des mathématiques. Cherchant a vérifier, de manière pratique, comment ces relations entre histoire des mathématiques et l`enseignement des mathématiques peuvent se matérialiser sous la forme d`activités didactiques, nous avons effectué un sondage sur les oeuvres du mathématicien Joseph Louis Lagrange (1736-1813) et identifié le potentiel d`exploration éducatif, de l`oeuvre Leçons élémentaires sur les mathématiques données a l`École Normale en 1795, de cet mathématicien. L`objectif principal de notre étude était de faire des recherches sur le potentiel d`une oeuvre antique dédié à l`enseignement des mathématiques et de la considérer comme support conceptuel et didactique pour la création d`un modèle d`activités didactiques pour l`enseignement des mathématiques, dans la formation des enseignants de mathématiques et aussi en ce qui concerne l`apprentissage des mathématiques des élèves de l`école primaire. Nous avons fait une lecture, la traduction et l`ajout de notes et commentaires sur le travail et une recherche bibliographique sur la relation entre l`histoire des mathématiques et l`enseignement des mathématiques, de façon a comprendre les aspects conceptuels et didactiques pour l`élaboration d`um module activités didactiques pour l`enseignement des mathématiques basée sur certains chapitres du livre de Lagrange. À cette fin, l`oeuvre a été utilisé comme source primaire et a été étudié sous un fondement théorique appuyer sur les travaux des Institut de recherche sur l`enseignement des mathématiques IREM. Dans le module élaboré, les activités apportent les contenus dans une suite integrée à une logique de classe, à partir de la lecture directe des découpages du texte original, disposés entre les questions et les situations-problémes , historiquement mis en contexte avec la période et associés à des contenus spécifiques. Comme il s`agit d`une recherche basée sur l`exploitation de livres anciens, nous croyons que des modules d`activités basées sur des source primaires peuvent être utilisées comme un matériel pédagogique pour la formation des enseignants de mathématiques ainsi que pour les dernières années de l`école élémentaire, reformulées ou accrues d`autres questions telles l`intérêt de chaque enseignant qui l`utilise

Indicadores de alteração hidrológica no Alto Rio Paraná: intervenções humanas e implicações na dinâmica do ambiente fluvial

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)