16 resultados para dedução
em Universidade Federal do Rio Grande do Norte(UFRN)
Resumo:
Eventually, violations of voltage limits at buses or admissible loadings of transmission lines and/or power transformers may occur by the power system operation. If violations are detected in the supervision process, corrective measures may be carried out in order to eliminate them or to reduce their intensity. Loading restriction is an extreme solution and should only be adopted as the last control action. Previous researches have shown that it is possible to control constraints in electrical systems by changing the network topology, using the technique named Corrective Switching, which requires no additional costs. In previous works, the proposed calculations for verifying the ability of a switching variant in eliminating an overload in a specific branch were based on network reduction or heuristic analysis. The purpose of this work is to develop analytical derivation of linear equations to estimate current changes in a specific branch (due to switching measures) by means of few calculations. For bus-bar coupling, derivations will be based on short-circuit theory and Relief Function methodology. For bus-bar splitting, a Relief Function will be derived based on a technique of equivalent circuit. Although systems of linear equations are used to substantiate deductions, its formal solution for each variant, in real time does not become necessary. A priority list of promising variants is then assigned for final check by an exact load flow calculation and a transient analysis using ATP Alternative Transient Program. At last, results obtained by simulation in networks with different features will be presented
Resumo:
Formalization of logical systems in natural deduction brings many metatheoretical advantages, which Normalization proof is always highlighted. Modal logic systems, until very recently, were not routinely formalized in natural deduction, though some formulations and Normalization proofs are known. This work is a presentation of some important known systems of modal logic in natural deduction, and some Normalization procedures for them, but it is also and mainly a presentation of a hierarchy of modal logic systems in natural deduction, from K until S5, together with an outline of a Normalization proof for the system K, which is a model for Normalization in other systems
Resumo:
Neste trabalho objetivou-se verificar, teoricamente , a possibilidade de manutenção de heterozigotos, em populações de plantas autógamas, na presença e na ausência de seleção dependente de frequência (SDF). Considerou-se apenas um loco com dois alelos. Utilizou-se a dedução algébrica de formulas referentes a alguns modelos de populações e um programa para simular a sucessão das gerações em uma calculadora científica avançada. Comparou-se os resultados do modelo com os dados obtidos experimentalmente por Allard e Workman (1963) e por Harding, Allard e Smeltzer (1966). Os coeficientes de determinação foram 0,9653 e 0,9166 para a primeira e a segunda comparação, respectivamente. Estes coeficientes indicam que o modelo D representa de modo bastante fidedigno as variações observadas em populações experimentais de plantas predominantemente autógamas
Resumo:
Malaria is a disease of global distribution, recognized by governments around the world as a serious public health problem, affecting more than 109 countries and territories and endangering more than 3.3 billion people. The economic costs of this disease are also relevant: the African continent itself has malaria-related costs of about $ 12 billion annually. Nowadays, in addition to chloroquine, Plasmodium falciparum is resistant to many drugs used in the treatment of malaria, such as amodiaquine, mefloquine, quinine and sulfadoxine-pyrimethamine; resistance of Plasmodium vivax to treatments, although less studied, is also reported. Nature, in general, is responsible for the production of most known organic substances, and the plant kingdom is responsible for the most of the chemical diversity known and reported in the literature. Most medicinal plants commercialized in Brazil, however, are of exotic origin, which makes the search for endemic medicinal plants, besides a patent necessity, a fascinating subject of academic research and development. This study aimed to: (i) verify the antimalarial activity of ethanolic and hydroalcoholic extracts of Boerhavia paniculata Rich. And acetonic extract of Clethra scabra Pers. in Swiss albino mice infected by Plasmodium berghei NK65, (ii) observe possible combined effects between the course of infection by P. berghei NK65 and administration of these extracts in Swiss albino mice, and (iii) conduct a preliminary study of the acute toxicity of these extracts in Swiss albino mice. All extracts notable pharmacological activities - with parasite infections inhibitions ranging from 22% to 54%.These characteristics suggest that the activities are relevant, although comparatively lower than the activity displayed by the positive control group (always above 90%). The general framework of survival analysis demonstrates an overall reduction in survival times for all groups. Necroscopy has not pointed no change in color, shape, size and/or consistency in the evaluated organs - the only exception was the livers of rats submitted to treatment to hydroalcoholic extracts: these organs have been presented in a slightly congestive aspect with mass increasing roughly 28% higher than the other two groups and a p-value of 0.0365. The 250 mg/Kg ethanolic group has been pointed out by the Dunn s post test, as the only class with simultaneous inequalities (p<0.05) between positive and negative control groups. The extracts, notably ethanol extract, have, in fact, a vestigial antimalarial activity, although well below from the ones perceived to chloroquine-treated groups; nevertheless, the survival times of the animals fed with the extracts do not rise by presence of such therapy. Both the toxicopharmacological studies of the synergism between the clinical course of malaria and administration of extracts and the isolated evaluation of toxicity allow us to affirm the absence of toxicity of the extracts at the level of CNS and ANS, as well as their non-influence on food and water consumption patterns, until dosages of 500 mg/Kg. Necroscopic analysis leads us to deduct a possible hepatotoxic effect of hydroalcoholic extract at dosages of 500 mg/Kg, and an innocuous tissue activity of the ethanol extract, in the same dosage. We propose a continuation of the studies of these extracts, with protocol modifications capable of addressing more clearly and objectively their pharmacological and toxicological aspects
Resumo:
This study was elaborated based on our research of the work Mithologiques by the anthropologist Claude Lévi-Strauss (1908-2009), which affirms that languages, indigenous myths and music are related. He proposes that the understanding of myths occurs in a similar manner as with an orchestral score. In the course of his tetralogy we investigated the musical terms used in the analysis and in the division of the chapters, especially in the first volume of his work. Several compositional procedures and forms are named. Composers in pairs are categorized: Sebastian Bach for the code, Ludwig van Beethoven for the message, and Richard Wagner for the myths. In this deduction, we structured in parts: theme and variations, sonata and fugue with the aforementioned composers. Within the greatness of anthropological study, from among over 800 myths, we selected the first five of the indigenous tribe Bororo to discuss within the Theme and Variation segment. In the Sonata part there are two myths with the same theme: The wife of the jaguar which relates to the compositional structure, and four myths about The origin of women. Finally, in the segment related to the Fugue, we collected four myths that address The shortness of life. Honoring the many terms expressed in opposition, contrast, or symmetry under consideration in Levi-Strauss work, we entitled this thesis emphasizing the migration between the tempos Largo and Prestíssimo as these are oppositional presentations in music. Fifteen musical myths accompany the work supported by selected narratives. In light of this we questioned, we questioned: how are incest, murder and other events part of a society that elevates nature as an extension of life itself? And how did Lévi-Strauss think that anthropology harmonized with music? In the preparation of this study, philosophers like Peter Sloterdijk discuss the circular territory of Mythology
Resumo:
Brazilian law passes through a crisis of effectiveness commonly attributed to the extravagance of fundamental rights and public shortage. However, public finances are not dogmatically structured to solve the conflicts around the limitations of public spending. There are ethical conditioning factors, like morality, proportionality and impartiality, however, these principles act separately, while the problem of public shortage is holistic. Also, the subjectivity of politics discretionary in the definition of public spending, which is supported in an indeterminate concept of public interest, needs material orientation about the destination of public funds, making it vulnerable to ideological manipulation, resulting in real process of catching rights. Not even the judicial activism (such as influx of constitutionalism) is shown legally appropriate. The Reserve of Possible, also presents basic ethical failure. Understanding the formation of public shortage is therefore essential for understanding the crisis of effectiveness of state responsibilities, given the significant expansion of the state duty of protection, which does not find legal technique of defense of the established interests. The premise of argument, then, part of the possibility of deducting minimal model ethical of desire to spend (public interest) according to objective parameters of the normative system. Public spending has always been treated disdainfully by the Brazilian doctrine, according to the legal character accessory assigned to the monetary cost. Nonetheless, it is the meeting point between economics and law, or is in the marrow of the problem of public shortage. Expensive Subjects to modernity, as the effectiveness of fundamental rights, pass necessarily an ethical legal system of public spending. From the ethical principles deducted from the planning, only the democratic principle guides the public spending through the approval of public spending in the complex budget process. In other words, there is an ethical distancing of economic reality in relation to state responsibilities. From the dogmatic belief of insufficiency, public spending is evaluated ethically, according to the foundations of modern constitutionalism, in search of possible of the financial reserve, certain that the ethics of public economy is a sine qua non condition for legal ethics.
Resumo:
This work consists in the development of a theoretical and numerical analysis for frequency selective surfaces (FSS) structures with conducting patch elements, such as rectangular patches, thin dipoles and cross dipoles, on anisotropic dielectric substrates. The analysis is developed for millimeter wave band applications. The analytical formulation is developed in the spectral domain, by using a rigorous technique known as equivalent transmission line method, or immitance approach. The numerical analysis is completed through the use of the Galerkin's technique in the Fourier transform domain, using entire-domain basis functions. In the last decades, several sophisticated analytical techniques have been developed for FSS structure applications. Within these applications, it can be emphasized the use of FSS structures on reflecting antennas and bandpass radomes. In the analysis, the scattered fields of the FSS geometry are related to the surface induced currents on the conducting patches. After the formulation of the scattering problem, the numerical solution is obtained by using the moment method. The choice of the basis functions plays a very important role in the numerical efficiency of the numerical method, once they should provide a very good approximation to the real current distributions on the FSS analyzed structure. Thereafter, the dyadic Green's function components are obtained in order to evaluate the basis functions unknown coefficients. To accomplish that, the Galerkin's numerical technique is used. Completing the formulation, the incident fields are determined through the incident potential, and as a consequence the FSS transmission and reflection characteristics are determined, as function of the resonant frequency and structural parameters. The main objective of this work was to analyze FSS structures with conducting patch elements, such as thin dipoles, cross dipoles and rectangular patches, on anisotropic dielectric substrates, for high frequency applications. Therefore, numerical results for the FSS structure main characteristics were obtained in the millimeter wave bando Some of these FSS characteristics are the resonant
Resumo:
This work whose title is "The transcendental arguments: Kant Andy Hume's problem" has as its main objective to interpret Kant's answer to Hume's problem in the light of the conjunction of the causality and induction themes which is equivalent to skeptical- naturalist reading of the latter. In this sense, this initiative complements the previous treatment seen in our dissertation, where the same issue had been discussed from a merely skeptical reading that Kant got from Hume thought and was only examined causality. Among the specific objectives, we list the following: a) critical philosophy fulfills three basic functions, a founding, one negative and one would argue that the practical use of reason, here named as defensive b) the Kantian solution of Hume's problem in the first critisism would fulfill its founding and negative functions of critique of reason; c) the Kantian treatment of the theme of induction in other criticisms would will fulfill the defense function of critique of reason; d) that the evidence of Kant's answer to Hume's problem are more consistent when will be satisfied these three functions or moments of criticism. The basic structure of the work consists of three parts: the first the genesis of Hume's problem - our intention is to reconstruct Hume's problem, analyzing it from the perspective of two definitions of cause, where the dilution of the first definition in the second match the reduction of psychological knowledge to the probability of following the called naturalization of causal relations; whereas in the second - Legality and Causality - it is stated that when considering Hume in the skeptic-naturalist option, Kant is not entitled to respond by transcendental argument AB; A⊢B from the second Analogy, evidence that is rooted in the position of contemporary thinkers, such as Strawson and Allison; in third part - Purpose and Induction - admits that Kant responds to Hume on the level of regulative reason use, although the development of this test exceeds the limits of the founding function of criticism. And this is articulated in both the Introduction and Concluding Remarks by meeting the defensive [and negative] function of criticism. In this context, based on the use of so-called transcendental arguments that project throughout the critical trilogy, we provide solution to a recurring issue that recurs at several points in our submission and concerning to the "existence and / or the necessity of empirical causal laws. In this light, our thesis is that transcendental arguments are only an apodictic solution to the Hume s skeptical-naturalist problem when is at stake a practical project in which the interest of reason is ensured, as will, in short, proved in our final considerations
Resumo:
In the Einstein s theory of General Relativity the field equations relate the geometry of space-time with the content of matter and energy, sources of the gravitational field. This content is described by a second order tensor, known as energy-momentum tensor. On the other hand, the energy-momentum tensors that have physical meaning are not specified by this theory. In the 700s, Hawking and Ellis set a couple of conditions, considered feasible from a physical point of view, in order to limit the arbitrariness of these tensors. These conditions, which became known as Hawking-Ellis energy conditions, play important roles in the gravitation scenario. They are widely used as powerful tools for analysis; from the demonstration of important theorems concerning to the behavior of gravitational fields and geometries associated, the gravity quantum behavior, to the analysis of cosmological models. In this dissertation we present a rigorous deduction of the several energy conditions currently in vogue in the scientific literature, such as: the Null Energy Condition (NEC), Weak Energy Condition (WEC), the Strong Energy Condition (SEC), the Dominant Energy Condition (DEC) and Null Dominant Energy Condition (NDEC). Bearing in mind the most trivial applications in Cosmology and Gravitation, the deductions were initially made for an energy-momentum tensor of a generalized perfect fluid and then extended to scalar fields with minimal and non-minimal coupling to the gravitational field. We also present a study about the possible violations of some of these energy conditions. Aiming the study of the single nature of some exact solutions of Einstein s General Relativity, in 1955 the Indian physicist Raychaudhuri derived an equation that is today considered fundamental to the study of the gravitational attraction of matter, which became known as the Raychaudhuri equation. This famous equation is fundamental for to understanding of gravitational attraction in Astrophysics and Cosmology and for the comprehension of the singularity theorems, such as, the Hawking and Penrose theorem about the singularity of the gravitational collapse. In this dissertation we derive the Raychaudhuri equation, the Frobenius theorem and the Focusing theorem for congruences time-like and null congruences of a pseudo-riemannian manifold. We discuss the geometric and physical meaning of this equation, its connections with the energy conditions, and some of its several aplications.
Resumo:
The standard kinetic theory for a nonrelativistic diluted gas is generalized in the spirit of the nonextensive statistic distribution introduced by Tsallis. The new formalism depends on an arbitrary q parameter measuring the degree of nonextensivity. In the limit q = 1, the extensive Maxwell-Boltzmann theory is recovered. Starting from a purely kinetic deduction of the velocity q-distribution function, the Boltzmann H-teorem is generalized for including the possibility of nonextensive out of equilibrium effects. Based on this investigation, it is proved that Tsallis' distribution is the necessary and sufficient condition defining a thermodynamic equilibrium state in the nonextensive context. This result follows naturally from the generalized transport equation and also from the extended H-theorem. Two physical applications of the nonextensive effects have been considered. Closed analytic expressions were obtained for the Doppler broadening of spectral lines from an excited gas, as well as, for the dispersion relations describing the eletrostatic oscillations in a diluted electronic plasma. In the later case, a comparison with the experimental results strongly suggests a Tsallis distribution with the q parameter smaller than unity. A complementary study is related to the thermodynamic behavior of a relativistic imperfect simple fluid. Using nonequilibrium thermodynamics, we show how the basic primary variables, namely: the energy momentum tensor, the particle and entropy fluxes depend on the several dissipative processes present in the fluid. The temperature variation law for this moving imperfect fluid is also obtained, and the Eckart and Landau-Lifshitz formulations are recovered as particular cases
Resumo:
Considering a non-relativistic ideal gas, the standard foundations of kinetic theory are investigated in the context of non-gaussian statistical mechanics introduced by Kaniadakis. The new formalism is based on the generalization of the Boltzmann H-theorem and the deduction of Maxwells statistical distribution. The calculated power law distribution is parameterized through a parameter measuring the degree of non-gaussianity. In the limit = 0, the theory of gaussian Maxwell-Boltzmann distribution is recovered. Two physical applications of the non-gaussian effects have been considered. The first one, the -Doppler broadening of spectral lines from an excited gas is obtained from analytical expressions. The second one, a mathematical relationship between the entropic index and the stellar polytropic index is shown by using the thermodynamic formulation for self-gravitational systems
Resumo:
Considering a quantum gas, the foundations of standard thermostatistics are investigated in the context of non-Gaussian statistical mechanics introduced by Tsallis and Kaniadakis. The new formalism is based on the following generalizations: i) Maxwell- Boltzmann-Gibbs entropy and ii) deduction of H-theorem. Based on this investigation, we calculate a new entropy using a generalization of combinatorial analysis based on two different methods of counting. The basic ingredients used in the H-theorem were: a generalized quantum entropy and a generalization of collisional term of Boltzmann equation. The power law distributions are parameterized by parameters q;, measuring the degree of non-Gaussianity of quantum gas. In the limit q
Resumo:
Logic courses represent a pedagogical challenge and the recorded number of cases of failures and of discontinuity in them is often high. Amont other difficulties, students face a cognitive overload to understand logical concepts in a relevant way. On that track, computational tools for learning are resources that help both in alleviating the cognitive overload scenarios and in allowing for the practical experimenting with theoretical concepts. The present study proposes an interactive tutorial, namely the TryLogic, aimed at teaching to solve logical conjectures either by proofs or refutations. The tool was developed from the architecture of the tool TryOcaml, through support of the communication of the web interface ProofWeb in accessing the proof assistant Coq. The goals of TryLogic are: (1) presenting a set of lessons for applying heuristic strategies in solving problems set in Propositional Logic; (2) stepwise organizing the exposition of concepts related to Natural Deduction and to Propositional Semantics in sequential steps; (3) providing interactive tasks to the students. The present study also aims at: presenting our implementation of a formal system for refutation; describing the integration of our infrastructure with the Virtual Learning Environment Moodle through the IMS Learning Tools Interoperability specification; presenting the Conjecture Generator that works for the tasks involving proving and refuting; and, finally to evaluate the learning experience of Logic students through the application of the conjecture solving task associated to the use of the TryLogic
Resumo:
The farm’s rural dwellings of creation from the Seridó Potiguar microregion, built in the nineteenth century, became a reference by its vernacular character, i.e. these buildings, besides having recognized relevance to the identity of the region, they are adapted to the conditions of the place in many aspects (economic, cultural, construction, physical, et.) and consist in protective spaces in relation to hostile characteristics of Seridó’s climate. Considering the above premise, the following question arises: What characteristics of the nineteenth century Seridó Potiguar’s cattle farms are crucial for them to be a protective space in relation to the semiarid climate? In order to answer the question, this research aim to identify which particularities of the Seridó’s farmhouses that contribute to adaptability in these buildings to semiarid climate, as protection environments; and contribute to the stock valuation of the architectural heritage concerned. Therefore, procedures were adopted divided into two stages. Were first identified the recurring characteristics in the studied buildings, through typological study performed from existing inventories (DINIZ, 2008; FEIJÓ, 2002; IPHAN, 2012). To define the type it worked up with the concept that merges Durand’s analytical typology that identifies the similarities and differences to classify buildings, having the character of historical survey and architectural documentation, with the definition proposed by Argan (1963) that the type is not defined a priory, but the deduction from a number of illustrative cases which have formal and functional similarity with each other. Then worked up in a sample of five different types with each other, defined by the possibility of access to the interior of the houses, proximity to other copies, good state of conservation and preservation. The contemplated farms were: Pitombeiras, Agenus e Garrotes in Acari’s town, and the municipality of Caicó, Palma and Penedo. The second stage consists of the architectural survey, photographic record, digital three-dimensional modeling (aiming to expand the existing documentation and registration) and thermal monitoring over approximately a representative day in five farmhouses, relating the thermal performance of the houses with their individual characteristics. The selected variables for analysis monitoring are based on the thermal comfort adaptive model (SPAGNOLO and DE DEAR, 2003 apud NEGREIROS, 2010). The characteristics of the houses were analyzed as meeting the passive thermal conditioning strategies recommended by NBR 15220 (ABNT, 2005), for the bioclimatic zone 7 where the municipalities of Caicó and Acari are located. The house’s analysis of the operating temperatures revealed that 90% of the times of day the environments are within the comfort range. The farmhouses, which had a higher degree of compliance with recommended bioclimatic strategies, had the best thermal performance. In environments (usually the kitchen and rooms with low ceiling heights, exposed to west radiation) which still had discomfort hours, the thermal comfort can be reached with air movement approximately 1,0 m/s.
Resumo:
The farm’s rural dwellings of creation from the Seridó Potiguar microregion, built in the nineteenth century, became a reference by its vernacular character, i.e. these buildings, besides having recognized relevance to the identity of the region, they are adapted to the conditions of the place in many aspects (economic, cultural, construction, physical, et.) and consist in protective spaces in relation to hostile characteristics of Seridó’s climate. Considering the above premise, the following question arises: What characteristics of the nineteenth century Seridó Potiguar’s cattle farms are crucial for them to be a protective space in relation to the semiarid climate? In order to answer the question, this research aim to identify which particularities of the Seridó’s farmhouses that contribute to adaptability in these buildings to semiarid climate, as protection environments; and contribute to the stock valuation of the architectural heritage concerned. Therefore, procedures were adopted divided into two stages. Were first identified the recurring characteristics in the studied buildings, through typological study performed from existing inventories (DINIZ, 2008; FEIJÓ, 2002; IPHAN, 2012). To define the type it worked up with the concept that merges Durand’s analytical typology that identifies the similarities and differences to classify buildings, having the character of historical survey and architectural documentation, with the definition proposed by Argan (1963) that the type is not defined a priory, but the deduction from a number of illustrative cases which have formal and functional similarity with each other. Then worked up in a sample of five different types with each other, defined by the possibility of access to the interior of the houses, proximity to other copies, good state of conservation and preservation. The contemplated farms were: Pitombeiras, Agenus e Garrotes in Acari’s town, and the municipality of Caicó, Palma and Penedo. The second stage consists of the architectural survey, photographic record, digital three-dimensional modeling (aiming to expand the existing documentation and registration) and thermal monitoring over approximately a representative day in five farmhouses, relating the thermal performance of the houses with their individual characteristics. The selected variables for analysis monitoring are based on the thermal comfort adaptive model (SPAGNOLO and DE DEAR, 2003 apud NEGREIROS, 2010). The characteristics of the houses were analyzed as meeting the passive thermal conditioning strategies recommended by NBR 15220 (ABNT, 2005), for the bioclimatic zone 7 where the municipalities of Caicó and Acari are located. The house’s analysis of the operating temperatures revealed that 90% of the times of day the environments are within the comfort range. The farmhouses, which had a higher degree of compliance with recommended bioclimatic strategies, had the best thermal performance. In environments (usually the kitchen and rooms with low ceiling heights, exposed to west radiation) which still had discomfort hours, the thermal comfort can be reached with air movement approximately 1,0 m/s.