Study of the dimensions of double-torsion test specimens

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Characteristics of the double-torsion test to determine the R-curve of ceramic materials

Double-torsion tests were carried out on a commercial ceramic floor tile to verify whether this test is suitable for determining the R-curve of ceramics. The instantaneous crack length was obtained by means of compliance calibration, and it was found that the experimental compliance underestimates the real crack length. The load vs. displacement curves were also found to drop after maximum loading, causing the stress intensity factor to decline. The R-curves were calculated by two methods: linear elastic fracture mechanics and the energetic method. It was obtained that the average values of crack resistance, R, and the double of the work of fracture, 2 · γwof, did not depend on notch length, a0, which is a highly relevant finding, indicating that these parameters were less dependent on the test specimen's geometry. The proposal was to use small notches, which produce long stable crack propagation paths that in turn are particularly important in the case of coarse microstructures.

The double triangular test in practice

The double triangular test was introduced twenty years ago, and the purpose of this paper is to review applications that have been made since then. In fact, take-up of the method was rather slow until the late 1990s, but in recent years several clinical trial reports have been published describing its use in a wide range of therapeutic areas. The core of this paper is a detailed account of five trials that have been published since 2000 in which the method was applied to studies of pancreatic cancer, breast cancer, myocardial infarction, epilepsy and bedsores. Before those accounts are given, the method is described and the history behind its evolution is presented. The future potential of the method for sequential case-control and equivalence trials is also discussed. Copyright © 2004 John Wiley & Sons, Ltd.

Double effort test for evaluation of aerobic capacity of diet-induced obese rats

Introduction: The literature lacks studies about lactate actions and some limitations in studies involving healthy individuals or patients with some metabolic disorder. Objectives: This study aimed to evaluate the protocol of double effort test for obese-induced rats. Methods: Fourteen male Wistar rats were divided into two groups: Control (Con) and Obese (Obe). The control group was fed with standard chow and water ad libitum. The obese group was fed with standard chow, water ad libitum and hyperlipidic diet. Twelve weeks after the beginning of the hyperlipidic diet, insulin tolerance test, Maximal Lactate Steady State (MLSS) test and the double efforts test were performed. Results: The diet was effective to promote obesity. The obese group decreased insulin sensitivity in approximately 19% (Con = 2.156 ± 0.1187 AU vs Obe = 1.742 ± 0.1551 AU). The lactate concentration and velocity of anaerobic threshold at MLSS test were 3.780 ± 0.09 mmol/L e 18 m.min-1 in both groups. The velocity of anaerobic threshold estimated by double efforts test was 15.59±0.653 m.min-1 in Con group control animals and 16.42±0.672 m.min-1 in Obe group. The double effort test underestimated around 13% and 8.7% the aerobic capacity in control and obese groups respectively, however, presented significant correlation with MLSS (r = 0,88; P < 0,0075 controls / r = 0,92; P < 0,0031 obese). Conclusion: So, the double effort test can be an interesting alternative to evaluate the aerobic capacity for both healthy sedentary and obese animals.

An investigation of the hot-torsion test used in studies of hot workability

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Double blind test series

Braille is a communication tool in decline, in America by 80% since 1950, and in the UK to the extent that only 1% of blind people are now thought to read Braille.1, 2 There are a variety of causal factors, including the phasing out of Braille instruction due to the educational mainstreaming of blind children and the resistance to learning Braille by those who lose sight later in life.3Braille is a writing system of raised dots that allows blind people to read and write tactilely. Each Braille character comprises a cell of six potentially raised dots, two dots across and three dots down. It is designed only to communicate the message and does not convey the tonality provided by visual fonts.However, in his book Design Meets Disability, Graham Pullin, observes that: “Braille is interesting and beautiful, as abstract visual and tactile decoration, intriguing and indecipherable to the nonreader ” and continues; “…braille could be decorative for sighted people.”4I assert that the increasing abandonment of Braille frees it from its restrictive constraints, opening it to exploration and experimentation, and that this may result in Braille becoming dynamic expression for the sighted, as well as the partially sighted and blind.Printmaking is well suited for this exploration. Printmaking processes and techniques can result in prints aesthetically compelling to both senses of sight and touch. Established approaches, such as flocking, varnishes, puff-ink, embossing and die cut, combined with experiments in new techniques in laser cutting and 3D printing, create visually and texturally vibrant prints.In this paper I will detail my systematic investigation of sensually expressive printmaking concentrating on the issues surrounding Braille as a printmaking design element paying particular attention to the approaches and techniques used not only in producing its visual style but to those techniques used to keep it integrally tactile.

Microsomal redox systems in brown adipose tissue: high lipid peroxidation, low cholesterol biosynthesis and no detectable cytochrome P-450

The presence of redox systems in microsomes of brown adipose tissue (BAT) in cold exposed rats was investigated and compared with liver. BAT microsomes showed high activity of lipid peroxidation measured both by the formation of malondialdehyde (MDA) and by oxygen uptake. NADH and NADPH dependent cytochrome c reductase activity were present in both BAT and liver microsomes. Aminopyrine demethylase and aniline hydroxylase activities, the characteristic detoxification enzymes in liver microsomes could not be detected in BAT microsomes. BAT minces showed very poor incorporation of [1-14C]acetate and [2-14C]-mevalonate in unsaponifiable lipid fraction compared to liver. Biosynthesis of cholesterol and ubiquinone, but not fatty acids, and the activity of 3-hydroxy-3-methyl glutaryl CoA reductase appear to be very low in BAT. Examination of difference spectra showed the presence of only cytochrome b 5 in BAT microsomes. In addition to the inability to detect the enzyme activities dependent on cytochrome P-450, a protein with the characteristic spectrum, molecular size in SDS-PAGE and interaction with antibodies in double diffusion test, also could not be detected in BAT microsomes. The high activity of lipid peroxidation in microsomes, being associated with large oxygen uptake and oxidation of NADPH, will also contribute to the energy dissipation as heat in BAT, considered important in thermogenesis.

Concrete damage plasticity model for modeling FRP-to-concrete bond behavior

The technique of externally bonding fiber-reinforced polymer (FRP) composites has become very popular worldwide for retrofitting existing reinforced concrete (RC) structures. Debonding of FRP from the concrete substrate is a typical failure mode in such strengthened structures. The bond behavior between FRP and concrete thus plays a crucial role in these structures. The FRP-to-concrete bond behavior has been extensively investigated experimentally, commonly using a single or double shear test of the FRP-to-concrete bonded joint. Comparatively, much less research has been concerned with numerical simulation, chiefly due to difficulties in the accurate modeling of the complex behavior of concrete. This paper presents a simple but robust finite-element (FE) model for simulating the bond behavior in the entire debonding process for the single shear test. A concrete damage plasticity model is proposed to capture the concrete-to-FRP bond behavior. Numerical results are in close agreement with test data, validating the model. In addition to accuracy, the model has two further advantages: it only requires the basic material parameters (i.e., no arbitrary user-defined parameter such as the shear retention factor is required) and it can be directly implemented in the FE software ABAQUS.

Nivel de concordancia en la interpretación de calcificaciones mamarias en las pacientes que fueron llevadas a biopsia por esterotaxia en la FCI –IC entre noviembre de 2004 a noviembre de 2008

Propósito: establecer la variabilidad inter observador en la categorización de las microcalcificaciones mamográficas según la clasificación vigente (BIRADS 4 edicion) entre dos evaluadores mediante un estudio de concordancia de consistencia. Determinar las razones de probabilidad y el valor predictivo positivo de categoría de microcalcificaciones. Materiales y métodos: este estudio incluye 108 placas mamográficas de 107 pacientes , mujeres con edades entre los 31 y 90 años a quienes se les había practicado biopsia guiada con esterotaxia por calcificaciones mamarias en la FCI – IC entre noviembre de 2004 a noviembre de 2008 y cuyos registros mamograficos se encontraran disponibles para análisis. Se diseñó una hoja de recolección de datos con la cual dos examinadores calificaban las calcificaciones según se describen en el BIRADS 4 edición sin conocer el resultado de la patología ni la calificación del otro examinador (doble ciego). Posteriormente se aplico un análisis Kappa Ponderado para determinar el nivel de concordancia más allá del azar entre los dos examinadores. Se Calcularon los valores predictivos positivos y las razones de probabilidad para cada categoría de calcificaciones.

On the development of the electrochemical potentiokinetic method

The development of electrochemical potentiokinetic methods as applied to the testing of metals and alloys is followed from its early phases up to its latest advances relating to intergranular corrosion, SCC and pitting corrosion tests of stainless steels and special alloys and to the examination of their structure and properties. In assessing the susceptibility to intergranular and pitting corrosion by potentiokinetic polarization tests, the polarization curves which apply to the bulk of the alloy grains (the matrix) must be distinguished from those pertaining to grain boundaries. Cyclic polarization measurements such as the electrochemical potentiokinetic reactivation (EPR) test make it possible to derive the alloy's susceptibility to intergranular, pitting and crevice corrosion from characteristic potentials and other quantities determined in the 'double loop' test. EPR is rapid and responds to the combined effects of a number of factors that influence the properties of materials. The electrochemical p otentiokinetic tests are sensitive enough to detect structural changes in heat treated materials ranging far beyond the stainless steels alone, and can be used for non-destructive testing aimed at elucidating the properties and behavior of materials. © 2001 Elsevier Science Ltd. All rights reserved.

Padrão de sensibilidade de cepas de Enterobacter spp isoladas na região de Presidente Prudente - SP

Enterobacter spp. are considered important causing agents of infection, specially in hospitalized individuals. The natural resistance of these microorganisms and the great facility to develop resistance to new antimicrobial agents make this genus an important object of study. In this work, 176 strains isolated from various clinical samples were used from hospitalized patients (University Hospital Domingos Leonardo Cerávolo) and from clinic patients (Clinical Laboratory from Unoeste), both situated in Presidente Prudente - SP. E. cloacae (78.9%), E. aerogenes (7.9%) and E. (pantoea) agglomerans (3.9%) were the ones more frequently isolated. Eleven antimicrobial agents were tested by the disk diffusion method and around 90% of the strains presented resistance to the cephalotin, ampicillin and cefaclor. Strains of E. (pantoea) agglomerans presented wide profile of sensibility However one strain of E. cloacae presented resistance to all the antimicrobial agents. The antimicrobial agents with greater inhibitory activity were imipenem and cefepime, for this reason these antimicrobial agents could be the treatment of choice in emergencial therapeutic. This emergencial therapy can be applied with relative security, whereas the data obtained in this study show homogeneity in the profile of sensibility to these antimicrobial agents, independent of the infection site and from the isolated species. The ESBL enzyme could not be detected in no one of the strains by the double diffusion test.

O efeito de dois modelos de treinamento contínuo ou intervalado sobre metabolismo muscular e capacidade aeróbia de ratos obesos induzidos por dieta

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação da resistência à fratura torcional de diferentes instrumentos rotatórios de níquel-titânio

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)