77 resultados para apollonian packings
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A new constructive family of asymptotically good lattices with respect to sphere packing density is presented. The family has a lattice in every dimension n >= 1. Each lattice is obtained from a conveniently chosen integral ideal in a subfield of the cyclotomic field Q(zeta(q)) where q is the smallest prime congruent to 1 modulo n.
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This article presents as main focus, a research where it was verified and it analyzed the found problems of usability during the manuscript of the plastic packings of 20 liters for agrotóxicos. On the basis of the raised theoretical data and in the diagnosised problems of usability in the field research, a Guide of Ergonomic Parameters for the Design elaborated itself or Redesign of the Packings Plastic for Agrotóxicos, contributing of practical form, accomplishes and ergonomic for the development of these packings.
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Label is every and any information regarding to a product that is transcribed in its package. For the consumer it is through the nutritional information tables contained in the labels that there is access to data such as quantity and percentage of nutrients contained in foods. Through this knowledge, it is possible to make healthier food choices, minimizing the negative effects related to poor nutrition in the population, especially among children, the most critical rate of obesity incidence. The aim of this study was to evaluate the appropriateness of the labels of some foods consumed by children in relation to the Recommended Daily Intake (RDI) and verify that the general aspects of the labels were in accordance with Brazilian regulations. Five products were selected like snacks, corn snacks, snacks, peanut, peanuts, potato snacks and biscuit recipes. The labels of different brands of each snack were analyzed using the Checklist of Labelling, which is based on RDC No. 259 and RDC No. 360. The nutritional adequacy of nutrients from these foods (carbohydrates, protein, total fat, saturated fat, trans fat, dietary fiber and sodium) was evaluated in relation to that recommended by the RDA for children 4-8 years old. There was small percentage of mistakes in the labels of the analyzed foods, about 12%, being the presence of words that induce the consumers to the misunderstanding the irregularity with larger predominance, present in 25% of the labels. Other items in disagreement were the incomplete specification of the addictive ones alimentary in the list of ingredients and the absence of instructions about the conservation of the foods after opening the packings, both with percentile of occurrence of 18,75%. The high sodium content found in the nutritional information of food shows that should reduce the consumption of these products among children.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Spin systems in the presence of disorder are described by two sets of degrees of freedom, associated with orientational (spin) and disorder variables, which may be characterized by two distinct relaxation times. Disordered spin models have been mostly investigated in the quenched regime, which is the usual situation in solid state physics, and in which the relaxation time of the disorder variables is much larger than the typical measurement times. In this quenched regime, disorder variables are fixed, and only the orientational variables are duly thermalized. Recent studies in the context of lattice statistical models for the phase diagrams of nematic liquid-crystalline systems have stimulated the interest of going beyond the quenched regime. The phase diagrams predicted by these calculations for a simple Maier-Saupe model turn out to be qualitative different from the quenched case if the two sets of degrees of freedom are allowed to reach thermal equilibrium during the experimental time, which is known as the fully annealed regime. In this work, we develop a transfer matrix formalism to investigate annealed disordered Ising models on two hierarchical structures, the diamond hierarchical lattice (DHL) and the Apollonian network (AN). The calculations follow the same steps used for the analysis of simple uniform systems, which amounts to deriving proper recurrence maps for the thermodynamic and magnetic variables in terms of the generations of the construction of the hierarchical structures. In this context, we may consider different kinds of disorder, and different types of ferromagnetic and anti-ferromagnetic interactions. In the present work, we analyze the effects of dilution, which are produced by the removal of some magnetic ions. The system is treated in a “grand canonical" ensemble. The introduction of two extra fields, related to the concentration of two different types of particles, leads to higher-rank transfer matrices as compared with the formalism for the usual uniform models. Preliminary calculations on a DHL indicate that there is a phase transition for a wide range of dilution concentrations. Ising spin systems on the AN are known to be ferromagnetically ordered at all temperatures; in the presence of dilution, however, there are indications of a disordered (paramagnetic) phase at low concentrations of magnetic ions.
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In this work we have investigated the intercalation of electron-donors between NbS2 slabs in Nb-based layer sulfides. Two series of Sr substituted Nb-based misfit sulfides belonging to the 1.5Q/1H and 1Q/1H series of misfit layer compounds have been synthesised. For large lanthanides (Ln=La, Ce), only the 1Q/1H compounds formed whereas for smaller lanthanides and yttrium, both types of phases can be obtained. The crystal structure of misfit sulfide (Pr0.55Sr0.45S)1.15NbS2 has been refined using the composite approach. In the Q-slab, Pr-atoms are partly replaced by Sr with a random distribution over one cation position. The crystal structure of misfit sulfide [(Sm1/3Sr2/3S)1.5]1.15NbS2 belonging to the 1.5Q/1H series have also been determined. The obtained results suggest a preferred occupancy of the cation positions in the slab where Sr atoms mainly occupy positions on the exterior of the slab while Sm atoms are in the center of the slab. The (La1-xSrxS)1.15NbS2 solid solution (0.1<x<0.9) has also been studied. It was found that the maximum value of Sr substitution is 40-50% and therefore, the minimal value of charge transfer to stabilize this structure type is about 0.6ē per Nb atom. An attempt to synthesize SrxNbS2 (0.1≤x≤0.5) intercalates was made but single phases were not obtained and increasing the temperature from 1000оС to 1100оС leads to the decomposition of these intercalates. Single crystals of Sr0.22Nb1.05S2 and Sr0.23NbS2 were found and their structures were determined. The structures belong to two different types of packings with statistical distribution of Sr between layers. A new superconducting sulfide, "EuNb2S5", was investigated by ED and HREM and its structure model consisting of Nb7S14 and (Eu3S4)2 slabs alternating along the c-axis is suggested. An attempt to suggest a model for the structure of "SrNb2S5" by means of X-ray single crystal diffraction was made. The proposed structure consists of two types of slabs: a Nb7S14 and a [Sr6(NbS4)2S] slab with niobium in tetrahedral coordination. It is shown that "SrNb2S5" and "EuNb2S5" are have similar structures. For the first time, single crystals of the complex sulfide BaNb0.9S3 have also been studied by means of X-ray single crystal diffraction. The single crystal refinement and EDX analysis showed the existence of cation vacancies at the niobium position. BaNb0.9S3 has also been studied by ED and no superstructure was found which implies that and the vacancies are statistically distributed. No improvement of the magnetic properties of the studied compounds was observed in comparison to NbS2.
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We present new algorithms to approximate the discrete volume of a polyhedral geometry using boxes defined by the US standard SAE J1100. This problem is NP-hard and has its main application in the car design process. The algorithms produce maximum weighted independent sets on a so-called conflict graph for a discretisation of the geometry. We present a framework to eliminate a large portion of the vertices of a graph without affecting the quality of the optimal solution. Using this framework we are also able to define the conflict graph without the use of a discretisation. For the solution of the maximum weighted independent set problem we designed an enumeration scheme which uses the restrictions of the SAE J1100 standard for an efficient upper bound computation. We evaluate the packing algorithms according to the solution quality compared to manually derived results. Finally, we compare our enumeration scheme to several other exact algorithms in terms of their runtime. Grid-based packings either tend to be not tight or have intersections between boxes. We therefore present an algorithm which can compute box packings with arbitrary placements and fixed orientations. In this algorithm we make use of approximate Minkowski Sums, computed by uniting many axis-oriented equal boxes. We developed an algorithm which computes the union of equal axis-oriented boxes efficiently. This algorithm also maintains the Minkowski Sums throughout the packing process. We also extend these algorithms for packing arbitrary objects in fixed orientations.
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We have performed Monte Carlo and molecular dynamics simulations of suspensions of monodisperse, hard ellipsoids of revolution. Hard-particle models play a key role in statistical mechanics. They are conceptually and computationally simple, and they offer insight into systems in which particle shape is important, including atomic, molecular, colloidal, and granular systems. In the high density phase diagram of prolate hard ellipsoids we have found a new crystal, which is more stable than the stretched FCC structure proposed previously . The new phase, SM2, has a simple monoclinic unit cell containing a basis of two ellipsoids with unequal orientations. The angle of inclination is very soft for length-to-width (aspect) ratio l/w=3, while the other angles are not. A symmetric state of the unit cell exists, related to the densest-known packings of ellipsoids; it is not always the stable one. Our results remove the stretched FCC structure for aspect ratio l/w=3 from the phase diagram of hard, uni-axial ellipsoids. We provide evidence that this holds between aspect ratios 3 and 6, and possibly beyond. Finally, ellipsoids in SM2 at l/w=1.55 exhibit end-over-end flipping, warranting studies of the cross-over to where this dynamics is not possible. Secondly, we studied the dynamics of nearly spherical ellipsoids. In equilibrium, they show a first-order transition from an isotropic phase to a rotator phase, where positions are crystalline but orientations are free. When over-compressing the isotropic phase into the rotator regime, we observed super-Arrhenius slowing down of diffusion and relaxation, and signatures of the cage effect. These features of glassy dynamics are sufficiently strong that asymptotic scaling laws of the Mode-Coupling Theory of the glass transition (MCT) could be tested, and were found to apply. We found strong coupling of positional and orientational degrees of freedom, leading to a common value for the MCT glass-transition volume fraction. Flipping modes were not slowed down significantly. We demonstrated that the results are independent of simulation method, as predicted by MCT. Further, we determined that even intra-cage motion is cooperative. We confirmed the presence of dynamical heterogeneities associated with the cage effect. The transit between cages was seen to occur on short time scales, compared to the time spent in cages; but the transit was shown not to involve displacements distinguishable in character from intra-cage motion. The presence of glassy dynamics was predicted by molecular MCT (MMCT). However, as MMCT disregards crystallization, a test by simulation was required. Glassy dynamics is unusual in monodisperse systems. Crystallization typically intervenes unless polydispersity, network-forming bonds or other asymmetries are introduced. We argue that particle anisometry acts as a sufficient source of disorder to prevent crystallization. This sheds new light on the question of which ingredients are required for glass formation.
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The purpose of this paper is to introduce ideas that have emerged during the course of writing a book on Swedish welfare in the 1990s. The book is the result of many years of writing about two subjects: Swedish drug policy and the Swedish welfare state. The one very specialised, the other, more general. I first became interested in Swedish drug policy on a research visit to Örebro Län in 1986. A social worker showed me a copy of the county's drug policy programme and explained the significance of the 'restrictive line'. I have spent the years since that visit, trying to understand and explain the Swedish goal of a drug-free society (Gould 1988, 1994, 1996b). I only began to write about the welfare state in Sweden in the early 1990s, just as things were beginning to go wrong for the economy (Gould 1993a, 1993b, 1996a, 1999). For the last few years I have intended to write a book on the events covered by the period 1991-1998 - the years of a Bourgeois and a Social Democratic Government -which would bring the two halves of my work together. Material for this study has been accumulated over many years. A number of research visits have been made; large numbers of academics, politicians, civil servants, journalists, unemployed people, social workers and their clients have been interviewed; and extensive use has been made of academic, administrative and public libraries. Since September 1991 I have systematically collected articles from Dagens Nyheter about social services, social insurance, health care, employment, social issues and problems, the economy and politics. The journal Riksdag och Departement (Parliament and Ministry), which summarises a wide range of public documents, has been invaluable. Friends and informal contacts have also given me insights into the Swedish way of life. The new book is based upon all of these experiences. This paper will begin with a brief account of major global social and economic changes that have occurred in the last twenty years. This is intended to provide a background to the more recent changes that have occurred in Swedish society in the last decade. It will be suggested that the changes in Sweden, particularly in the field of welfare, have been less severe than elsewhere and that this is due to political, institutional and cultural resistance. The paper will conclude by arguing that Sweden, as an exemplar of an Apollonian modern society, has had much to fear from the Dionysian characteristics of postmodernity.
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El propósito de esta comunicación es examinar la competencia del filósofo en el texto que hoy conocemos como Primer Alcibíades o Alcibíades Mayor. El trabajo propone la lectura del diálogo como un texto de filosofía política. La hipótesis sostenida es que el diálogo fue escrito con la intención de explicar la filosofía como una forma de intervenir políticamente basada en la exégesis filosófica de la sentencia apolínea "Conócete a ti mismo". Se argumenta que la perspectiva del texto se fundamenta en el principio de que la frase lleva consigo una exhortación a ejercer la política de manera recta. El diálogo, pues, no sólo contiene un análisis filosófico sobre la competencia adecuada para el ejercicio del poder, sino que también analiza cómo esta competencia se relaciona con la política, lo que pone a la filosofía en conflicto con las téchnai practicadas en la ciudad
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Casa Grande y Senzala, obra cumbre del sociólogo brasileño Gilberto Freyre, ha guiado de una u otra forma el recorrido seguido por la gran mayoría de los estudios históricos abocados al sistema patriarcal del ingenio azucarero. El presente trabajo propone un análisis del catolicismo brasileño durante el período esclavista, en el contexto de una reinterpretación de la obra de Freyre en función del antagonismo entre las categorías de apolíneo y dionisíaco. Esta religiosidad brasileña se nos presentará así como una experiencia eminentemente dionisíaca, frente al carácter apolíneo de la ortodoxia cristiana, y un elemento clave dentro del modelo planteado por Freyre
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Casa Grande y Senzala, obra cumbre del sociólogo brasileño Gilberto Freyre, ha guiado de una u otra forma el recorrido seguido por la gran mayoría de los estudios históricos abocados al sistema patriarcal del ingenio azucarero. El presente trabajo propone un análisis del catolicismo brasileño durante el período esclavista, en el contexto de una reinterpretación de la obra de Freyre en función del antagonismo entre las categorías de apolíneo y dionisíaco. Esta religiosidad brasileña se nos presentará así como una experiencia eminentemente dionisíaca, frente al carácter apolíneo de la ortodoxia cristiana, y un elemento clave dentro del modelo planteado por Freyre
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El propósito de esta comunicación es examinar la competencia del filósofo en el texto que hoy conocemos como Primer Alcibíades o Alcibíades Mayor. El trabajo propone la lectura del diálogo como un texto de filosofía política. La hipótesis sostenida es que el diálogo fue escrito con la intención de explicar la filosofía como una forma de intervenir políticamente basada en la exégesis filosófica de la sentencia apolínea "Conócete a ti mismo". Se argumenta que la perspectiva del texto se fundamenta en el principio de que la frase lleva consigo una exhortación a ejercer la política de manera recta. El diálogo, pues, no sólo contiene un análisis filosófico sobre la competencia adecuada para el ejercicio del poder, sino que también analiza cómo esta competencia se relaciona con la política, lo que pone a la filosofía en conflicto con las téchnai practicadas en la ciudad
Resumo:
Casa Grande y Senzala, obra cumbre del sociólogo brasileño Gilberto Freyre, ha guiado de una u otra forma el recorrido seguido por la gran mayoría de los estudios históricos abocados al sistema patriarcal del ingenio azucarero. El presente trabajo propone un análisis del catolicismo brasileño durante el período esclavista, en el contexto de una reinterpretación de la obra de Freyre en función del antagonismo entre las categorías de apolíneo y dionisíaco. Esta religiosidad brasileña se nos presentará así como una experiencia eminentemente dionisíaca, frente al carácter apolíneo de la ortodoxia cristiana, y un elemento clave dentro del modelo planteado por Freyre
Resumo:
El propósito de esta comunicación es examinar la competencia del filósofo en el texto que hoy conocemos como Primer Alcibíades o Alcibíades Mayor. El trabajo propone la lectura del diálogo como un texto de filosofía política. La hipótesis sostenida es que el diálogo fue escrito con la intención de explicar la filosofía como una forma de intervenir políticamente basada en la exégesis filosófica de la sentencia apolínea "Conócete a ti mismo". Se argumenta que la perspectiva del texto se fundamenta en el principio de que la frase lleva consigo una exhortación a ejercer la política de manera recta. El diálogo, pues, no sólo contiene un análisis filosófico sobre la competencia adecuada para el ejercicio del poder, sino que también analiza cómo esta competencia se relaciona con la política, lo que pone a la filosofía en conflicto con las téchnai practicadas en la ciudad