Repositório RCAAP

O presente trabalho teve por objetivo avaliar a produção e a qualidade das sementes obtidas de plantas de cenoura, das cultivares Brasília e Carandaí. O delineamento experimental foi em blocos ao acaso, com quatro repetições e cinco plantas úteis por parcela. Adotou-se o sistema semente-raiz-semente e indução floral por vernalização das raízes, durante 40 dias, a 5 °C. Foram avaliados o número de umbelas, as produções de sementes por planta e por umbela, a massa (g) de mil sementes, a germinação e a primeira contagem de germinação em cada classe de umbela. A cultivar Brasília superou a Carandaí na produção de sementes por planta (52 g), em virtude da maior produção nas umbelas secundárias (38 g), e não diferiu da cultivar Carandaí quanto à produção nas umbelas primárias e terciárias. Nas demais características avaliadas não foram observadas diferenças entre as cultivares. A produção por umbela foi-se reduzindo sucessivamente das primárias (7,5 g por umbela) às secundárias (3,0 g por umbela) e às terciárias (0,5 g por umbela). As sementes das umbelas primárias apresentaram maior massa (média de 2,1 g por mil sementes) em relação às secundárias (1,6 g por mil sementes) que, por sua vez, superaram as terciárias (1,4 g por mil sementes). As sementes das umbelas primárias e secundárias apresentaram maior poder germinativo comparativamemte às terciárias.

Foi realizado um experimento em casa de vegetação com o objetivo de avaliar a relação entre pH da rizosfera e tolerância ao Al de cinco genótipos de café, na presença e na ausência de calagem. As plantas de café foram desenvolvidas em caixas plásticas, com as raízes próximas da tampa. Após 90 dias as tampas foram removidas e uma fina camada de agar contendo indicador foi derramada sobre a superfície. Também foram avaliados a produção de biomassa seca da parte aérea e das raízes, o comprimento e a superfície de raízes. Quando o solo foi corrigido observou-se o desenvolvimento da coloração amarela próximo às raízes, indicando o abaixamento do pH em H2O. O resultado foi confirmado pela avaliação do pH do solo e da rizosfera com variações de 0,2 e 0,3 unidades de pH. Por outro lado, na presença de Al não houve diferença entre o pH do solo e o da rizosfera, indicando que a alteração no pH desta não parece ser o mecanismo de tolerância ao Al em cafeeiros, uma vez que os genótipos sensíveis e tolerantes apresentaram o mesmo comportamento.

A thirty three year-old, male patient was admitted at the Hospital of the São Paulo University School of Medicine, at the city of São Paulo, Brazil, with complaint of pains, tingling and decreased sensibility in the right hand for the last four months. This had progressed to the left hand, left foot and right foot, in addition to a difficulty of flexing and stretching in the left foot. Tests were positive for HBeAg, IgM anti-HBc and HBsAg, thus characterizing the condition of acute hepatitis B. The ALT serum level was 15 times above the upper normal limit. Blood glucose, cerebral spinal fluid, antinuclear antibodies (ANA) and anti-HIV and anti-HCV serum tests were either normal or negative. Electroneuromyography disclosed severe peripheral neuropathy with an axon prevalence and signs of denervation; nerve biopsy disclosed intense vasculitis. The diagnosis of multiple confluent mononeuropathy associated to acute hepatitis B was done. This association is not often reported in international literature and its probable cause is the direct action of the hepatitis B virus on the nerves or a vasculitis of the vasa nervorum brought about by deposits of immune complexes.

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A. actinomycetemcomitans, B. forsythus, P. gingivalis, C. rectus, E. corrodens, P. intermedia, F. nucleatum, and T. denticola were identified from subgingival plaque from 50 periodontal patients and 50 healthy subjects. PCR products from each species showed a specific band and could be used to identify periodontal organisms from clinical specimens. Identical negative or positive results between PCR and culture occurred in 66% (A. actinomycetemcomitans) to 93% (F. nucleatum) of the samples. PCR detection odds ratio values for A. actinomycetemcomitans, B. forsythus, C. rectus, E. corrodens, P. intermedia, and T. denticola were significantly associated with disease having a higher OR values for B. forsythus (2.97, 95% CI 1.88 - 4.70). Cultures showed that A. actinomycetemcomitans, B. forsythus and P. intermedia were associated with periodontitis, however, P. gingivalis, C. rectus, E. corrodens and F. nucleatum were not significantly associated with the disease.

The aim of this paper is to present and discuss the results obtained with a methodology used to characterize the concrete and to evaluate the structural safety against fatigue of the reinforced concrete bridge number 50A located in the Carajás railroad. An "in situ" inspection was carried out in order to assess the evolution of damage in structural elements, with reference to information available in existing projects, calculation memory and reporting of previous inspections. Extractions of concrete testimonies, alkalinity tests, sclerometry, pacometry and laboratory tests were also performed to characterize the materials mechanically and estimate the structural behavior of the bridge under higher future loads.

Punching strength is a critical point in the design of flat slabs and due to the lack of a theoretical method capable of explaining this phenomenon, empirical formulations presented by codes of practice are still the most used method to check the bearing capacity of slab-column connections. This paper discusses relevant aspects of the development of flat slabs, the factors that influence the punching resistance of slabs without shear reinforcement and makes comparisons between the experimental results organized in a database with 74 slabs carefully selected with theoretical results using the recommendations of ACI 318, EUROCODE 2 and NBR 6118 and also through the Critical Shear Crack Theory, presented by Muttoni (2008) and incorporated the new fib Model Code (2010).

This paper presents the analysis of the mechanical and durable properties of recycled aggregate concrete (RAC) for using in concrete. The porosity of recycled coarse aggregates is known to influence the fresh and hardened concrete properties and these properties are related to the specific mass of the recycled coarse aggregates, which directly influences the mechanical properties of the concrete. The recycled aggregates were obtained from construction and demolition wastes (CDW), which were divided into recycled sand (fine) and coarse aggregates. Besides this, a recycled coarse aggregate of a specific mass with a greater density was obtained by mixing the recycled aggregates of the CDW with the recycled aggregates of concrete wastes (CW). The concrete was produced in laboratory by combining three water-cement ratios, the ratios were used in agreement with NBR 6118 for structural concretes, with each recycled coarse aggregates and recycled sand or river sand, and the reference concrete was produced with natural aggregates. It was observed that recycled aggregates can be used in concrete with properties for structural concrete. In general, the use of recycled coarse aggregate in combination with recycled sand did not provide good results; but when the less porous was used, or the recycled coarse aggregate of a specific mass with a greater density, the properties of the concrete showed better results. Some RAC reached bigger strengths than the reference concrete.

This paper presents the experimental results of a research program with ceramic block masonry under compression. Four different block geometries were investigated. Two of them had circular hollows with different net area. The third one had two rectangular hollow and the last block was with rectangular hollows and a double central webs. The prisms and walls were built with two mortar type 1:1:6 (I) and 1:0,5:4 (II) (proportions by volume of cement: lime: sand). One:three small scale blocks were used to test block, prisms and walls on compression. It was possible to conclude that the block with double central webs gave better results of compressive strength showing to be more efficient. The mortar didn't influenced the compressive strength of prisms and walls.

The purpose of this paper is the analysis of the mechanical performance of concrete deep beams. To overcome the shortcomings inherent to the pioneer models, the finite element approximation on a non linear orthotropic model is employed. The obtained results showed that the practiced range on steel reinforcement did not influence, significantly, the beam performance, and one testifies a behavior, in the overall way, pursuant the fashion accepted in the scientific literature on the subject. Nevertheless, it should be detached that the material failure resulted from the concrete crushing on beneath load region, in addition to the occurrence of horizontal tensile stress and "snap back", at the upper edge in the center region, for the beams of greatest height.

To estimate the compressive strength of concrete is necessary in many reinforced concrete structures inspection works. In Brazil, the standard tests for this purpose are: Compressive test in drilled cores, rebound hammer test and ultrasonic test. In the United States and Europe are also regulated other techniques. The aim of this paper is to analyze the use of Pull Off test as an inspection tool of concrete and also disclose the possibility of use of complementary techniques to the standard ones in Brazil. The results show that the Pull Off test results in high correlation (R²> 0.93) with the compressive strength, measured in cylindrical and prismatic specimens. The rebound hammer test did not show satisfactory correlation (R²≅0.6) for the case of cylindrical specimens. The ultrasonic test showed high correlation (R²> 0.98), but behaves differently with the shape changing of the specimens.

A proposed adequation of NBR 6118, Item 7.4, related to shear strength of reinforced concrete beams is presented with aims to application on circular cross-section. The actual expressions are most suitable to rectangular cross-section and some misleading occurs when applied to circular sections at determination of VRd2, Vc and Vsw, as consequence of bw (beam width) and d (effective depth) definitions as well as the real effectiveness of circular stirrups. The proposed adequation is based on extensive bibliographic review and practical experience with a great number of infrastructure elements, such as anchored retaining pile walls, where the use of circular reinforced concrete members is frequent.

The Brazilian standard NBR 7212 states that the time of transporting the concrete between the start of mixing should be less than 90 minutes so that by the end of the discharge is a maximum of 150 minutes. Yet often, in construction, concrete is used after this period. In order to investigate the behavior of concrete after setting time of cement was cast six concrete mixtures with two types of cement. The mixtures were produced and kept fresh for six hours, adopting a procedure for maintenance of abatement by superplasticizer and agitation. The results show that of the test piece molded over six hours of maintained or increased the compressive strength average.

A general evaluation of some points of the South American seismic codes is presented herein, comparing them among themselves and with the American Standard ASCE/SEI 7/10 and with the European Standard Eurocode 8. The study is focused in design criteria for buildings. The Western border of South America is one of the most seismically active regions of the World. It corresponds to the confluence of the South American and Nazca plates. This region corresponds roughly to the vicinity of the Andes Mountains. This seismicity diminishes in the direction of the comparatively seismically quieter Eastern South American areas. The South American countries located in its Western Border possess standards for seismic design since some decades ago, being the Brazilian Standard for seismic design only recently published. This study is focused in some critical topics: definition of the recurrence periods for establishing the seismic input; definition of the seismic zonation and design ground motion values; definition of the shape of the design response spectra; consideration of soil amplification, soil liquefaction and soil-structure interaction; classification of the structures in different importance levels; definition of the seismic force-resisting systems and respective response modification coefficients; consideration of structural irregularities and definition of the allowable procedures for the seismic analyses. A simple building structure is analyzed considering the criteria of the several standards and obtained results are compared.

This paper presents a method to design membrane elements of concrete with orthogonal mesh of reinforcement which are subject to compressive stress. Design methods, in general, define how to quantify the reinforcement necessary to support the tension stress and verify if the compression in concrete is within the strength limit. In case the compression in membrane is excessive, it is possible to use reinforcements subject to compression. However, there is not much information in the literature about how to design reinforcement for these cases. For that, this paper presents a procedure which uses the model based on Baumann's [1] criteria. The strength limits used herein are those recommended by CEB [3], however, a model is proposed in which this limit varies according to the tensile strain which occur perpendicular to compression. This resistance model is based on concepts proposed by Vecchio e Collins [2].

Due to the large increase in the use of precast concrete structures in multistory buildings, this work covers a study on the behavior of beam-column connection with emphasis on the continuity provided by the slab reinforcement. Two prototypes were tested, each one with a different detail of the continuity reinforcement distribution. In both connections, the steel area used on the concrete cover of the hollow core slab was the same, varying the amount of bars that passed through the column and the ones that were placed adjacent to the column. The experimental results showed that the connection with bars adjacent to the column presented stiffness increase and a better cracking control. According to the classification the two tested connections can be considered semi-rigid.