103 resultados para Bar-Tal, Yoram
em Repositório da Produção Científica e Intelectual da Unicamp
Resumo:
To evaluate the influence of a fluorescent dye (rhodamine B) on the physical and mechanical properties of three different luting cements: a conventional adhesive luting cement (RelyX ARC, 3M/ESPE), a self-adhesive luting cement (RelyX U-200, 3M/ESPE), and a self-etching and self-adhesive luting cement (SeT PP, SDI). The cements were mixed with 0.03 wt% rhodamine B, formed into bar-shaped specimens (n = 10), and light cured using an LED curing unit (Radii, SDI) with a radiant exposure of 32 J/cm(2) . The Knoop hardness (KHN), flexural strength (FS), and Young's modulus (YM) analyses were evaluated after storage for 24 h. Outcomes were subjected to two-way ANOVA and Tukey's test (P = 0.05) for multiple comparisons. No significant differences in FS or YM were observed among the tested groups (P ≥ 0.05); the addition of rhodamine B increased the hardness of the luting cements tested. The addition of a fluorescent agent at 0.03 wt% concentration does not negatively affect the physical-mechanical properties of the luting cement polymerization behavior.
Resumo:
The aim of the present study was to compare four methods of fixation in mandibular body fractures. Mechanical and photoelastic tests were performed using polyurethane and photoelastic resin mandibles, respectively. The study groups contained the following: (I), two miniplates of 2.0 mm; (II) one 2.0 mm plate and an Erich arch bar; (III) one 2.4 mm plate and an Erich arch bar, and (IV) one 2.0 mm plate and one 2.4 mm plate. The differences between the mean values were analyzed using Tukey's test, the Mann-Whitney test and the Bonferroni correction. Group II recorded the lowest resistance, followed by groups I, IV and III. The photoelastic test confirmed the increase of tension in group II. The 2.4 mm system board in linear mandibular body fractures provided more resistance and the use of only one 2.0 mm plate in the central area of the mandible created higher tension.
Resumo:
This work was done with the objective of studying some physical and mechanical characteristics of the sugarcane bagasse ash added to a soil-cement mixture, in order to obtain an alternative construction material. The sugarcane bagasse ash pre-treatment included both sieving and grinding, before mixing with soil and cement. Different proportions of cement-ash were tested by determining its standard consistence and its compressive resistance at 7 and 28 days age. The various treatments were subsequently applied to the specimens molded with different soil-cement-ash mixtures which in turns were submitted to compaction, unconfined compression and water absorption laboratory tests. The results showed that it is possible to replace up to 20% of Portland cement by sugarcane bagasse ash without any damage to the mixture's compressive strength.
Resumo:
The physical model was based on the method of Newton-Euler. The model was developed by using the scientific computer program Mathematica®. Several simulations where tried varying the progress speeds (0.69; 1.12; 1.48; 1.82 and 2.12 m s-1); soil profiles (sinoidal, ascending and descending ramp) and height of the profile (0.025 and 0.05 m) to obtain the normal force of soil reaction. After the initial simulations, the mechanism was optimized using the scientific computer program Matlab® having as criterion (function-objective) the minimization of the normal force of reaction of the profile (FN). The project variables were the lengths of the bars (L1y, L2, l3 and L4), height of the operation (L7), the initial length of the spring (Lmo) and the elastic constant of the spring (k t). The lack of robustness of the mechanism in relation to the variable height of the operation was outlined by using a spring with low rigidity and large length. The results demonstrated that the mechanism optimized showed better flotation performance in relation to the initial mechanism.
Resumo:
A base-cutter represented for a mechanism of four bars, was developed using the Autocad program. The normal force of reaction of the profile in the contact point was determined through the dynamic analysis. The equations of dynamic balance were based on the laws of Newton-Euler. The linkage was subject to an optimization technique that considered the peak value of soil reaction force as the objective function to be minimized while the link lengths and the spring constant varied through a specified range. The Algorithm of Sequential Quadratic Programming-SQP was implemented of the program computational Matlab. Results were very encouraging; the maximum value of the normal reaction force was reduced from 4,250.33 to 237.13 N, making the floating process much less disturbing to the soil and the sugarcane rate. Later, others variables had been incorporated the mechanism optimized and new otimization process was implemented .
Resumo:
No Tillage system is fully incorporated to farming in the region of Campos Gerais, state of Paraná. Accuracy and precision in the planting process are items of great importance for the success of this system. In order to evaluate the planting process, thirty eight farms were selected as sites for analysis of the placement depth of seeds. The research area was 4 or 5 planting rows, evaluating 10 plantlets per row. The average seed depth was around 46 mm, and significant differences between rows were observed in 21 areas. The average coefficient of variation was around 20%, the statistical limit between medium and high. Analyses of other parameters show that those coefficients may represent different errors in the process. The planting process in Campos Gerais can be considered efficient regarding to the average seed depth. However, the analysis of variability implies de need of actions concerning to anthropic and machinery factors.
Resumo:
In order to determine the energy needed to artificially dry an agricultural product the latent heat of vaporization of moisture in the product, H, must be known. Generally, the expressions for H reported in the literature are of the form H = h(T)f(M), where h(T) is the latent heat of vaporization of free water, and f(M) is a function of the equilibrium moisture content, M, which is a simplification. In this article, a more general expression for the latent heat of vaporization, namely H = g(M,T), is used to determine H for cowpea, always-green variety. For this purpose, a computer program was developed which automatically fits about 500 functions, with one or two independent variables, imbedded in its library to experimental data. The program uses nonlinear regression, and classifies the best functions according to the least reduced chi-squared. A set of executed statistical tests shows that the generalized expression for H used in this work produces better results of H for cowpea than other equations found in literature.
Resumo:
Mental health problems are common in primary health care, particularly anxiety and depression. This study aims to estimate the prevalence of common mental disorders and their associations with socio-demographic characteristics in primary care in Brazil (Family Health Strategy). It involved a multicenter cross-sectional study with patients from Rio de Janeiro, São Paulo, Fortaleza (Ceará State) and Porto Alegre (Rio Grande do Sul State), assessed using the General Health Questionnaire (GHQ-12) and the Hospital Anxiety and Depression Scale (HAD). The rate of mental disorders in patients from Rio de Janeiro, São Paulo, Fortaleza and Porto Alegre were found to be, respectively, 51.9%, 53.3%, 64.3% and 57.7% with significant differences between Porto Alegre and Fortaleza compared to Rio de Janeiro after adjusting for confounders. Prevalence proportions of mental problems were especially common for females, the unemployed, those with less education and those with lower incomes. In the context of the Brazilian government's moves towards developing primary health care and reorganizing mental health policies it is relevant to consider common mental disorders as a priority alongside other chronic health conditions.
Resumo:
Several native herbaceous and subshrub species native to the Cerrado in Brazil are geophytes, that is, they survive the unfavorable dry season and low temperatures, that sometimes coincide with fire, with only the underground system intact. Vernonia oxylepis is one of these species and the aim of this study was to describe the morpho-anatomy of the tuberous root and bud formation on this structure. The main axis of this root is perpendicular to the soil surface, and from which aerial shoots arise periodically throughout the life cycle. On the upper portion of the root, self-grafting of the shoots occurs. The root stores lipids and fructans, exhibits contraction and produces reparatory buds; adventitious buds arise from proliferated pericycle. These characteristics may be related to adaptation of this species to conditions in the Cerrado.
Resumo:
In this paper, I argue against the contemporary tendency to confine ideology to the sphere of subjectivity and point of view, as defended by Paul Simpson (1993) in his book Language, Ideology, and Point of View. My principal criticism against the view is that it simply amounts to a re-affirmation of certain of the conceptual categories with which we have for long been accustomed to think. Rather, I contend, we ought to try to interrogate those very categories with a view to teasing out the instabilities that characterise them. I argue that there is an urgent need to deconstruct the very opposition between ideology, point of view etc. on the one hand, and science, theory, or whatever that one might wish to posit on the other.
Resumo:
The dialectic tension between the phenomenon of illiteracy and the remedial efforts of the literate to provide a voice for those who don t have one, reflects at the same time the difficulties that the emerging discourses have to struggle with, and highlights the importance of this struggle as one that belongs to the opressed, not the well-meaning educators and political activists. It also informs the latter s efforts on behalf of the uneducated. Naturally these issues have attracted a good deal of attention of some specialists in South America. There is now a movement afoot there that aims at placing illiterate discourse inside the societal discourse proper without letting the latter manipulate the former for its own ends. I will address the typical exigencies and limitations inherent in such efforts, but at the same time point to new ways of understanding and handling the problem of literacy in a developing country.
Resumo:
This article shows that the term functionalism, very often understood as a single or uniform approach in linguistics, has to be understood in its different perspectives. I start by presenting an opposing conception similar to the I-language vs E-language in Chomsky (1986). As in the latter conception , language can be understood as an abstract model of a mind internal mechanism responsible for language production and perception or, as in the former one, it can be the description of the external use of language. Also like with formalists , there are functionalists who look for cross-linguistic variation (and universals of language use) and functionalists who look for language internal variation. It is also shown that functionalists can differ in the extent to which social variables are considered in the explanation of linguistic form.
Resumo:
This paper reintroduces the discussion about stress-timing in Brazilian Portuguese (BP). It begins by surveying some phonetic and phonological issues raised by the syllable- vs stress-timed dichotomy which culminated with the emergence of the p-center notion. Strict considerations of timing of V-V units and stress groups are taken into account to analyze the long term coupling of two basic oscillators (vowel and stress flow). This coupling allows a two-parameter characterization of language rhythms (coupling strength and speech rate) revealing that BP utterances present a high-degree of syllable-timing. A comparison with other languages, including European Portuguese, is also presented. The results analyzed indicate that Major's arguments for considering Portuguese (sic) as stress-timing are misleading.
Resumo:
The present paper brings about a possible articulation between translation and body from a non-sublimated, pragmatic perspective on meaning, as suggested by Wittgenstein in his Philosophical Investigations. By considering theoretical elaborations within embodied realism and elsewhere on the role of the body in cognitive processes, together with a critique of the concept of translation somatics, as proposed by Douglas Robinson (1991), the paper highlights the situated and social character of the translator's body.
Resumo:
Aflatoxins are hepatotoxic metabolites produced by Aspergillus flavus and A. parasiticus on a number of agricultural commodities. This research was carried out to evaluate the ability of thermolysed and active Saccharomyces cerevisiae to attenuate liver damage caused by aflatoxin. Diets were prepared containing 0 aflatoxin; 400 mug kg-1 aflatoxin; 400 mug kg-1 aflatoxin plus 1% of dehydrated active yeast, and 400 mug kg-1 aflatoxin plus 1% of thermolysed yeast. A bioassay with Wistar rats was conducted for 28 days, and body organs were weighted and analyses of the liver tissue of the animals were performed. The relative weight of heart, kidneys and liver from animals submitted to the different treatments did not show any difference, and liver tissue of animals feeding on the aflatoxin-free diet was adopted as a toxicity-free pattern. Hepatic tissue of animals feeding on diets containing 400 mug kg-1 aflatoxin or the diet supplemented with 1% thermolysed yeast showed clear signs of toxicity and damage. Hepatic tissue of animals feeding on the diet containing 1% of dehydrated active yeast showed less toxicity signs and damage than those receiving the diet containing 400 mug kg-1 aflatoxin. Active, dehydrated yeast had the ability to reduce toxic effects caused by aflatoxin, but thermolysed yeast was not able to alleviate the effects of aflatoxin toxicity.