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The present study aims to establish a comparison of corrosion resistance between four (non-commercial) high manganese steel models in relation to 9% nickel steel in an aqueous solution of H2SO4. High manganese steels have emerged as an alternative material for the manufacture of equipment for the storage and transportation of liquefied petroleum gas due to their mechanical properties and mainly for the lower cost compared to 9% nickel steel. The electrochemical techniques used were open circuit potential, linear polarization and electrochemical impedance spectroscopy. The results obtained by these techniques have helped to understand the phenomena that produce a lower corrosion resistance of high manganese steels when compared to 9% nickel steel in aqueous solutions.

The effects of the prior austenite grain sizes in hydrogen embrittlement of Co-containing 18Ni 300 maraging steel were studied employing Slow Strain Rate Testing (SSRT) in 0.6 M NaCl electrolyte under simultaneuos cathodic polarization. The material was susceptible to hydrogen embrittlement in all investigated conditions. In addition, the examination of the fractured surface revealed that the presence of hydrogen in steel promotes the formation of quasi-cleavage regions and hydrogen-induced cracks along the grain boundaries. However, the refining of the prior austenite grain allowed an improvement in the HE resistance. Moreover, EBSD analysis showed that intergranular cracks propagated along to grain boundaries orientated to {001} planes parallel to normal direction, whereas they were deflected on {101} and {111} crystallographic planes.

Currently, there is a tendency to develop materials that have an increasingly specific purpose for a particular application and the composites can be part of these types of materials. In addition, there is a search for replacement of synthetic fibers with natural ones, because of concerns about the environment. Hybridization of glass fiber composites with sisal fibers can result in improved performance by combining the benefits of each fiber with various applications. Many studies are developed on these types of composites, sisal/glass hybrids, varying certain parameters, such as matrix, orientation of fibers, treatment of fibers, stacking of layers, composition of elements, method of manufacture, among others, characterizing the various types of properties. The present work organizes the researches on the hybrid composites of sisal/glass, in chronological order, highlighting the specifications and parameters used and the main results obtained.

The duct system is one of the structures that most need a series of conditions that require the system to have a certain flexibility of movement due to thermal stresses, changes in the direction of the duct system and the unevenness on the ground. Metal bellows are designed to provide flexibility to the system, however, to guarantee the proper properties in service one should consider the material used in the component manufacturing as well as the manufacturing process itself. This research aimed to study a case of failure due to the stress corrosion of an austenitic stainless steel expansion joint. For the assessment of the main factors that led to the failure of the expansion joint, some analyses were employed: microstructural characterization by optical microscopy and scanning electron microscopy (SEM); X-ray diffraction; solution annealing heat treatments and microhardness. The results showed that the cleaning conditions allowed pits and cavities to form on the inner surface of the bellows while the forming processes used in the bellows manufacturing of the expansion joints were responsible for providing the necessary metallurgical conditions for the nucleation and propagation of cracks from pits and cavities. From the results it was possible to enumerate a series of recommendations that take into account an adequate cleaning of the component as well as the appropriate thermal treatments to optimize the service life of the studied component.

Currently, surface treatments lead to inducing a superficial layer of several nanometers up to micrometer, which in some cases can be protective. In this experimental work, an oxide layer was generated under different atmospheres (CO2 and steam atmospheres) during the thermal aging treatment of two different maraging grades, 300 and 350. Afterwards, this layer was microstructural and mechanically characterized by advanced characterization techniques at the micro- and submicron length scale to highlight some information related to the generated oxide layer. The results showed that the oxide layer (in both grades) was made up of several compounds like: TiO2, MoO3, hematite (α-Fe2O3), and CoFe2O4, this being the majority compound distributed homogeneously throughout the layer. Furthermore, a nickel-rich austenitic phase at the interphase was mainly made up cobalt ions (Co2+), instead of iron ions (Fe2+), within the spinel lattice.

The electrochemical behavior of solution-annealed grade 300 and grade 350 maraging steels subjected to two different aging temperatures in an aqueous hydrofluoric acid (HF) medium was evaluated. The microstructural and hardness studies showed the effects of the chemical composition and heat treatments on the material properties. Although it is not possible to observe them, the fine intermetallic composites deposited during aging allow a significant increase in the hardness of materials, which was reduced when aged at 560¿°C, where there was formation of reverted austenite. The results showed that, in both steels, solution-annealed samples that were not aged showed a better corrosion behavior than the aged samples. The reversion of austenite during aging at temperatures above 560¿°C increases the phase limits and its susceptibility to corrosion. The greater amount of cobalt and titanium in grade 350 maraging steel increases the amount of fine intermetallic precipitate rich in molybdenum and titanium during aging, therefore improving its mechanical properties, but also reducing its corrosion resistance.

In this paper, we analyse the quantization of cyclotron orbits for a 2D non-relativistic and spinless charged particle under the influence of a static and uniform magnetic field, the Landau problem. We follow the algebraic approach of rising and lowering operators. The Hamiltonian is expressed in terms of the usual rising and lowering operators of an isotropic quantum oscillator. Through a Bogoliubov transformation, we show that the Hamiltonian may be reduced to the one of a quantum oscillator that accounts for the formation of infinitely degenerate Landau levels. The explicit form of the position-space wave functions of Fock–Darwin states for a vanishing parabolic confinement potential is worked out by applying the techniques of ladder operators and the induction method. To explore the internal dynamics of the electron states, we compute the Fock–Darwin states’ density currents expressing them in terms of the ladder operators. In the supplementary material, we provide the reader with Mathematica algorithm that can help perform some of the calculations exposed in the paper. The charged particle in a magnetic field is used to explore some of the fundamental concepts of quantum mechanics as commuting operators, simultaneous eigenstates, degeneracy, rising and lowering operators, etc. This approach can be used as supplementary material in undergraduate final-year courses like quantum mechanics or solid state physics.

A regiao do pre-sal e bastante agressiva para os materiais utilizados em tal ambiente devido a alguns fatores encontrados abaixo da camada pre-sal como : gases corrosivos, agua de poco de petroleo, altas pressoes, etc. Com o intuito de avaliar apenas os efeitos da agua de poco de petroleo na resistencia a corrosao dos acos inoxidaveis austeniticos em tal ambiente, dois acos inoxidaveis austeniticos e dois acos inoxidaveis super austeniticos foram testados em agua artificial de poco de petroleo utilizando-se a tecnica eletroquimica chamada Potencial Escalonado. Nesta tecnica, valores de potencial (vs Ag/AgCl ) sao aplicados em escalonamento de 50 mV a cada 1 h ate que a corrente de 1 mA seja atingida. Os resultados mostraram que os acos inoxidaveis austeniticos comuns nao sao adequados para o uso em ambientes contendo ions cloreto, como os encontrados na regiao do pre-sal. Eles mostraram corrosao por pite. Os acos inoxidaveis superausteniticos testados exibiram boa resistencia a corrosao nesse meio e isso pode ser uma solucao para aplicacoes na regiao do pre-sal.

Aging heat treatments in maraging steels are fundamental to achieve the excellent mechanical properties required in several industries, i.e., nuclear, automotive, etc. In this research, samples of maraging 300 alloy were aged using a novel procedure that combines different steps with two atmospheres (nitrogen and water vapor) for several hours. The oxidized surface layer was chemical, microstructural and micromechanically characterized. Due to the thermodynamic and kinetic conditions, these gases reacted and change the surface chemistry of this steel producing a thin iron-based oxide layer of a homogeneous thickness of around 500 nm. Within the aforementioned information, porosity and other microstructural defects showed a non-homogeneous oxide, mainly constituted by magnetite, nickel ferrite, cobalt ferrite, and a small amount of hematite in the more external parts of the oxide layer. In this sense, from a chemical point of view, the heat treatment under specific atmosphere allows to induce a thin magnetic layer in a mixture of iron, nickel, and cobalt spinel ferrites. On the other hand, the oxide layer presents an adhesive force 99 mN value that shows the capability for being used for tribological applications under sliding contact tests.

The pitting corrosion resistance of AL-6XN PLUS™ superaustenitic stainless steel, 304L, 316L, and 317L austenitic stainless steels was investigated using the cyclic polarization technique. These materials were evaluated in the as received condition and heat-treated at temperatures between 500 °C and 900 °C for 72 h. A thermodynamic simulation was performed using the software Thermocalc® to predict possible deleterious phases in selected temperatures. The simulations have predicted the sigma phase in the selected temperature range. An aqueous solution of sulfuric acid and sodium chloride was used as electrolyte in the corrosion tests. The results showed that pitting corrosion was not observed on the samples of AL-6XN PLUS™ steel. The 304L steel suffered pitting corrosion. All the polarization curves of this steel showed hysteresis characteristics of pitting corrosion. The 316L and 317L steels were resistant to pitting corrosion, but susceptible to crevice corrosion.

The increasing awareness of the environment protection has contributed to concerns regarding alternative procedures for recycling of plastic wastes. Since chemical processes are high cost, energy and often environment harmful, thermo-mechanical techniques of recycling rises as a good alternative. This research deals with mechanical characterization of thermo-mechanical recycling of composites based on recycled high density polyethylene (HDPE) from post-consumed motor-oil plastic containers as matrix and natural fibers (sisal) as reinforcement. The composites were made by extrusion and then melt blended in a compression mold. The sisal fibers do not contribute to increase tensile strength. As fiber content increases loss of ductility is observed.

Al-based composites were fabricated by solid-state route and were characterized by optic and scanning electron microscopy in order to follow their microstructural evolution. Composites were prepared using powder metallurgy techniques in order to obtain samples to carry out mechanical tests on hot extruded and machined samples. Microstructural characterization reveals that, by milling, a homogeneous dispersion of insoluble particles into Al matrix is obtained; this produced an important improvement on hardness and strength compared with the reference. Milling intensity and particle concentration have an important effect on the mechanical properties of composites.

Freshwater sponges are abundant in the Amazon region and they have been known to cause dermatitis (acute inflammation) since the beginning of the 20th century. To determine whether additional constituents, besides their body spicules, cause dermatological reactions in humans, an experimental study was developed and carried out using mice and Drulia uruguayensis prepared in three different forms: intact sponges (IS), macerated sponges (MS) or isolated spicules - megascleres (ISM). The cells most commonly involved in inflammatory reactions (mast cells, eosinophils and neutrophils), as well as intraepithelial lymphocytes and degranulated mast cells, were counted so that they could be used as parameters to determine which of the sponge preparations induced the greatest reaction. The effects of the sponge on the skin were then determined by histological analysis. The results obtained showed that IS caused the greatest inflammatory reaction (p = 0.000005), activating mainly mast cells (p = 0.0018). The histopathological analysis revealed a slight loss of continuity of the epidermis when ISM or IS were applied. These findings allow us to conclude that a structurally intact sponge can cause a greater inflammatory reaction in the first contact because of its ability to perforate the skin and allow inflammatory agents to enter. Other proteins present in dried sponge bodies could induce allergic but not toxic responses (in contact with the entire sponge, a large number of pharmacologically inert proteins may be introduced, with a potential allergen).

Submitted by Guilherme Lemeszenski (guilherme@nead.unesp.br) on 2013-08-22T18:56:08Z No. of bitstreams: 1 S0102-09352008000500003.pdf: 257919 bytes, checksum: d1422a2702180a82a41cc6fea3d62ec7 (MD5) Made available in DSpace on 2013-08-22T18:56:08Z (GMT). No. of bitstreams: 1 S0102-09352008000500003.pdf: 257919 bytes, checksum: d1422a2702180a82a41cc6fea3d62ec7 (MD5) Previous issue date: 2008-10-01 Made available in DSpace on 2013-09-30T19:49:44Z (GMT). No. of bitstreams: 2 S0102-09352008000500003.pdf: 257919 bytes, checksum: d1422a2702180a82a41cc6fea3d62ec7 (MD5) S0102-09352008000500003.pdf.txt: 24850 bytes, checksum: 1f0cdee8662fba360312abb716584dc9 (MD5) Previous issue date: 2008-10-01 Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-20T15:13:06Z No. of bitstreams: 2 S0102-09352008000500003.pdf: 257919 bytes, checksum: d1422a2702180a82a41cc6fea3d62ec7 (MD5) S0102-09352008000500003.pdf.txt: 24850 bytes, checksum: 1f0cdee8662fba360312abb716584dc9 (MD5) Made available in DSpace on 2014-05-20T15:13:06Z (GMT). No. of bitstreams: 2 S0102-09352008000500003.pdf: 257919 bytes, checksum: d1422a2702180a82a41cc6fea3d62ec7 (MD5) S0102-09352008000500003.pdf.txt: 24850 bytes, checksum: 1f0cdee8662fba360312abb716584dc9 (MD5) Previous issue date: 2008-10-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Observou-se significativo aumento de atividade das formas ativas das metaloproteinases -2 e -9 em gatos com tirotoxicose induzida e desmineralização óssea. As formas pró e intermediária da metaloproteinase -2 elevaram-se com 14 dias de administração hormonal, porém, posteriormente, houve uma tendência de queda. Observou-se correlação negativa entre a forma ativa das metaloproteinases de matriz -2 e -9 e a densidade mineral óssea da extremidade distal do rádio. Os resultados sugerem aumento da degradação da matriz colágena secundária com a elevação dos hormônios tiroidianos. Significant increase of activity of active forms of matrix metalloproteinases -2 and -9 in cats under induced thyrotoxicosis and bone demineralization was observed. Pro and intermediated forms of matrix metalloproteinases -2 and -9 increased at 14 days of hormonal treatment, followed by decrease tendency. A negative correlation between active forms of matrix metalloproteinases -2 and -9 and bone mineral density of radius distal extremity was also observed. The results suggest an increase of collagen matrix degradation secondary to high levels of thyroid hormones. Universidade Federal do Espírito Santo (UFES) Departamento de Medicina Veterinária UNESPAR FFALM UNESP, Fac Med Vet & Zootecnia, Botucatu, SP, Brazil UNICAMP Instituto de Biologia UNESP Inst Biociencias, Botucatu, SP, Brazil UNESP, Fac Med Vet & Zootecnia, Botucatu, SP, Brazil UNESP Inst Biociencias, Botucatu, SP, Brazil

We study the internal rotational dynamics of electronic beams in relation to the phase singularities of their wave functions. Given their complex singularity structure, Hermite-Gaussian beams and other superpositions of Laguerre-Gaussian modes are studied here. We show that by inspecting the lowest non-vanishing terms of the wave function near the singularity it is possible to infer the structure of the Bohmian streamlines. Conversely, starting from a map of the electron's Bohmian velocities, we demonstrate that it is possible to derive the form of the electron's wave function near the singularity. We outline a procedure that could yield an experimental method to determine the main parameters of the electron's wave function close to a singularity., Comment: 16 pages, 17 figures, 1 table

We study the spin dynamics of a 2DEG moving across a magnetic superlattice. We describe the spin transitions induced by sectionally homogeneous tilted magnetic fields and the spatial evolution of spin-1/2 wave functions: amplitude and phase, in terms of the tilting angle, the Fermi energy and the magnetic field strengths. Clear signatures of coherent spin mixing and coherent spin flipping processes are shown. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

We have studied the behavior of the Shubnikov-de Haas oscillations in magnetoresistance under applied magnetic fields with an arbitrary orientation. Different procedures to measure the Lande-g factor have been used in the literature. We propose four unambiguous methods and formulas for the evaluation of this quantity. The Lande-g factor obtained using these formulas compares within the 5% with the reported results of Brosig et al. [1] in InAs – AlSb quantum wells, Bompadre et al. [2] for Bismuth crystals, Kobayashi et al. [3] measuring magnetoresistance as a function of the gate Voltage and F. Fang et al. [4] for InAs – GaSb heterostructure. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

We study the Shubnikov-de Haas oscillations in the magnetoresistance and Landauer conductance of a three strip quasi-2D semiconductor wave guide with thickness δ z and transversal width Wy. We assume that the strip in the middle, of length l H , is subject to a homogeneous magnetic field, tilted by θ H with respect to the normal z of the 2DEG. The structure of the Shubnikov-de Haas oscillations, associated with spin parallel and antiparallel to the z-component of the magnetic field, and the finiteness of l H , lead us to define, related with the limits between the corresponding Landau levels and the continuous spectrum, two characteristic saturation fields B s a t , đ= 2Φ o /l H cosθ H (2n s π - 1/δ 2 z ) 1 / 2 and B s a t , Đ defined by the positive root of B 2 s a t , Đ + 4gΦ o /πl 2 H cos 2 θ H B s a t , Đ - B 2 s a t , đ= 0. Here g is the Lande factor, Φ o the unit magnetic flux and n s the charge concentration. We also obtain the polarization field B p = Φ 0 /g 2n s - π/δ 2 z .

A phenomenological theory to describe the electromagnetic properties of granular superconductors, based on known bulk superconductors expressions and conventional Josephson's junctions tunneling currents, is presented and succesfully used to fit distinct experimental results for the magnetic susceptibility as a function of the temperature and the applied magnetic field of rather different samples., Comment: 6 pages, 6 figures

A simple expression for the transport critical current, which describes rather well the Ambegaokar-Baratoff (A-B) to Ginsburg-Landau (G-L) crossover, is obtained from an elementary analysis of a Josephson junction subject to external magnetic fields within the Ginsburg-Landau theory. We show that the order parameter in the intergrain region depends crucially on the interplay of two characteristic lengths: the superconducting coherence length $\ensuremath{\xi}\ensuremath{\propto}(1\ensuremath{-}{T/T}_{c}{)}^{\ensuremath{-}1/2}$ and the junction-induced superconducting decoherence length ${\ensuremath{\zeta}}_{q}\ensuremath{\propto}(1\ensuremath{-}{T/T}_{c}{)}^{\ensuremath{-}\ensuremath{\alpha}}.$ Data for the transport critical current in granular YBCO samples are presented, and the A-B to G-L crossovers successfully described.

Objetivou neste trabalho avaliar o capim Marandu, sob pastejo através do corte rente ao solo (CS), pastejo simulado (PS) e extrusa ruminal (EXT) em delineamento inteiramente casualizado. Foram mensurados teores de matéria seca (MS), proteína bruta, extrato etéreo, fibra em detergente neutro (FDN), ácido (FDA), hemicelulose, celulose, lignina e cinzas, digestibilidade in vitro da matéria seca, carboidratos totais e não fibrosos. As amostras de PS apresentaram para MS, FDN e FDA valores de 25,19, 65,31 e 28,91 %. A FDN e FDA encontrados na EXT foram de 73,21 e 33,46 %, reflexo da seletividade do animal. Os valores de FDA apresentados para CS foram de 36,01 %. As amostras obtidas pela disponibilidade total e pastejo simulado não foram representativas da dieta ingerida pelos animais. A composição bromatológica da forragem é influenciada pelos diferentes métodos de amostragem.

We develop a Lie algebraic approach to systematically calculate the evolution operator of the generalized two-dimensional quadratic Hamiltonian with time-dependent coefficients. Although the development of the Lie algebraic approach presented here is mainly motivated by the two-dimensional quadratic Hamiltonian, it may be applied to investigate the evolution operators of any Hamiltonian having a dynamical algebra with a large number of elements. We illustrate the method by finding the propagator and the Heisenberg picture position and momentum operators for a two-dimensional charge subject to uniform and constant electro-magnetic fields., Comment: 17 pages, 3 tables

Estabeleceram-se valores de média radiodensidade do osso trabecular das vértebras lombares de 16 gatos adultos, hígidos, por meio da tomografia computadorizada quantitativa (TCQ). O valor médio de radiodensidade do osso trabecular da segunda vértebra lombar foi de 436,1±42,1 unidades Hounsfield, com distribuição não homogênea da radiodensidade no corpo vertebral.

A Hamiltonian approach is presented to study the two dimensional motion of damped electric charges in time dependent electromagnetic fields. The classical and the corresponding quantum mechanical problems are solved for particular cases using canonical transformations applied to Hamiltonians for a particle with variable mass. The Green's function is constructed and, from it, the motion of a Gaussian wave packet is studied in detail., Comment: 14 pages, 4 figures, misprints and figures corrected

This paper on the use of accident prediction models in urban areas is from the proceedings of 14th international Conference on Urban Transport and the Environment in the 21st Century, which was held in Malta in 2008. The authors present a case study in Lisbon, Portugal, to demonstrate the use of an accident prediction model. They stress that in order to develop an efficient and affective strategy towards road safety, administrators must have the proper tools for the quantification of safety levels and the explicit consideration of safety issues in the road management process. Accident prediction models are mathematical functions that describe the relation between the road safety and explanatory variables, such as traffic, road length, and carriageway width, number of intersections, etc. Accident prediction models for intersections include traffic volume and pedestrian data. Accident prediction models can be adapted to the urban context where they are applied, and supplemented by the use of a Geographic Information System (GIS) based methodology to analyze spatial patterns of road accidents. The authors discuss accident prediction models applied to urban areas and the use of data collected on road accidents, road infrastructure characteristics and traffic and land use information. The authors briefly describe the GIS Accident database that is currently in construction for the city of Lisbon (covering 2003 - 2007).

Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-27T11:22:44Z No. of bitstreams: 0Bitstream added on 2014-05-27T14:39:02Z : No. of bitstreams: 1 2-s2.0-78149421558.pdf: 416438 bytes, checksum: 229baa0f265679f394b1e22307828e53 (MD5) Made available in DSpace on 2014-05-27T11:22:44Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-12-01 Feline hyperthyroidism (thyrotoxicosis) is now recognised as the most common endocrine disease of the domestic cat. Feline hyperthyroidism cause multisystemic disorder associated with incresead circulating concentrations of the thyroid hormones, tri-iodothyronine (T3) and thyroxine (T4). Cardiovascular abnormalities in cats with spontaneous hyperthyroid have been described. Objective to determine heart size of progressing experimental thyrotoxicosis of 19 cats, using a vertebral scale system (VHS). The lateral, dorsoventral e ventrodorsal radiographs thoracic were measured using a vertebral scale system. Lateral radiographs thoracic to efficient develop that DV and VD. The VHS method is easy to use, allows objective assesment of heart size in cats hyperthyroid, and may be helpful to identify cardiomegaly and heart size progressing. Clínica Médica e Semiologia de Pequenos Animais Faculdades Luiz Meneghel da Universidade Estadual do Parana Bandeirantes PR e Doutorando da Faculdade de Medicina Veterinaria e Zootecnia da Universidade Estadual Paulista, Botucatu - SP Diagnóstico por Imagem e Clinica Medica de Animais de Companhia da Universidade Federal ES e Doutorando da Faculdade de Medicina Veterinária e Zootecnia da Universidade Estadual Paulista, Botucatu - SP Radiologia do Departamento de Reprodução Animal e Radiologia Veterinária Faculdade de Medicina Veterinária e Zootecnia Universidade Estadual Paulista, Botucatu - SP Médica Veterinária e Doutorando Faculdade de Medicina Veterinária e Zootecnia Universidade Estadual Paulista, Botucatu - SP Bioestatística do Instituto de Biologia Faculdade de Medicina Veterinária e Zootecnia Universidade Estadual Paulista, Botucatu - SP Clínica Médica e Semiologia de Pequenos Animais Faculdades Luiz Meneghel da Universidade Estadual do Parana Bandeirantes PR e Doutorando da Faculdade de Medicina Veterinaria e Zootecnia da Universidade Estadual Paulista, Botucatu - SP Diagnóstico por Imagem e Clinica Medica de Animais de Companhia da Universidade Federal ES e Doutorando da Faculdade de Medicina Veterinária e Zootecnia da Universidade Estadual Paulista, Botucatu - SP Radiologia do Departamento de Reprodução Animal e Radiologia Veterinária Faculdade de Medicina Veterinária e Zootecnia Universidade Estadual Paulista, Botucatu - SP Médica Veterinária e Doutorando Faculdade de Medicina Veterinária e Zootecnia Universidade Estadual Paulista, Botucatu - SP Bioestatística do Instituto de Biologia Faculdade de Medicina Veterinária e Zootecnia Universidade Estadual Paulista, Botucatu - SP

Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-27T11:22:20Z No. of bitstreams: 0Bitstream added on 2014-05-27T14:29:07Z : No. of bitstreams: 1 2-s2.0-47649099686.pdf: 693013 bytes, checksum: 28f67b7c41cd0e122b9c1f764aeb048b (MD5) Made available in DSpace on 2014-05-27T11:22:20Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-12-01 Hyperthyroidism can result in serious effects on the bone metabolism in humans as well as animals. For a better characterization of thyrotoxicosis effects, 16 cats were induced into thyrotoxicosis by intaking a dose of 150 μg/kg of sodium L-thyroxine every 24 hours during 42 days. The hormonal levels were evaluated by radioimmunoassay technique and the bone mineral density of the right distal radius extremity was measured through the radiographic optical densitometry. Was verified significant bone demineralization seven days of hormonal intake as weel as radius demineralization. Departamento de Zootecnia e Economia Rural Centro de Ciências Agrárias Universidade Federal do Espírito Santo, Alegre - ES Curso de Medicina Veterinária Faculdade Luiz Meneghel, Bandeirantes - PR Departamento de Reprodução Animal e Radiologia Veterinária Faculdade de Medicina Veterinária e Zootecnia Universidade Estadual Paulista, Botucatu - SP Departamento de Bioestatística Faculdade de Medicina Veterinária e Zootecnia Universidade Estadual Paulista, Botucatu - SP Departamento de Reprodução Animal e Radiologia Veterinária Faculdade de Medicina Veterinária e Zootecnia Universidade Estadual Paulista, Botucatu - SP Departamento de Bioestatística Faculdade de Medicina Veterinária e Zootecnia Universidade Estadual Paulista, Botucatu - SP

In this paper we introduce an alternative approach to studying the motion of a planar charged particle subject to a static uniform magnetic field. It is well known that an electric charge under a uniform magnetic field has a planar motion if its initial velocity is perpendicular to the magnetic field. Although some constants of motion (CsM), as the energy and the angular momentum, have been widely discussed for this system, others have been neglected. We find that the angular momentum, the generator of the magnetic translations and the magnetic Laplace–Runge–Lenz vector are CsM for this particular system. We show also that these three quantities form an orthogonal basis of vectors. The present work addresses many aspects of the motion of a charged particle in a magnetic field that should be useful for students and tutors of the classical mechanics courses at the senior undergraduate level.

Epidemic outbreaks of dermatitis caused by Hylesia sp which occurred in the coastal region of the State of S. Paulo during the period of December 1989 to December 1991 are confirmed. The incident assumed its greatest intensity in Bertioga, in Santos County, where 612 cases were registered. The outbreak also affected 12 other counties in that region and it was estimated that hundred of affected persons sought the Local Health Service Care. The majority presented with erythematous and prutiginous lesions and papula which lasted 7 to 14 days on average. Treatment consisted of systemic administration of antihistamines, and the use of topic corticosteroids and cold compresses. During the above-mentioned period, three epidemic episodes, coinciding with the rainy season (November to January), occurred. They were first observed in the northern part of the coastal area and then spread to the south. Information as to how avoid contact with the moth was the main prophylactic measure. In highly infested buildings the effectiveness of residual insecticide procedure was used in the attempt to reduce the level of moth infestation. Satisfactory results were obtained with deltametrin applied in a dosage of 50 mg/m2 of wall.

A tirotoxicose é caracterizada pelas excessivas concentrações séricas dos hormônios tiroidianos, podendo desencadear graves alterações no metabolismo ósseo, sendo a elevação da fosfatase alcalina total uma alteração laboratorial freqüentemente observada no hipertiroidismo felino. O aumento global dos níveis séricos de fosfatase alcalina pode ser decorrente de diferentes isoenzimas e, no caso do hipertiroidismo em humanos, as isoenzimas de origem óssea e hepática apresentam-se comumente elevadas. A partir da avaliação da bioquímica sérica de oito gatos com tirotoxicose induzida e elevação da fosfatase alcalina associada, o presente trabalho demonstra um aumento significativamente maior dos níveis séricos da fosfatase alcalina de origem óssea quando comparado com a isoenzima de origem hepática. Conclui-se que as alterações no metabolismo ósseo foram as principais responsáveis pelo aumento da fosfatase alcalina nos gatos com tirotoxicose induzida.

Using the exact two-propagating-modes solutions for electrons in a quasi-2D semiconductor wave guide under sectionally constant magnetic fields and spin-orbit interactions, it is explicitly shown that the Fano-like resonances and antiresonances lead to sudden suppressions and enhancements of the spin-dependent transmission probabilities. Our calculations show that when the magnetic-field-tilting angle θH is increased, the spin-field interaction becomes the most significant mechanism for the spin transitions in magnetic superlattices. Taking advantage of these spin-transport effects, simple and efficient spin-inverter devices are proposed. To better visualize the relative influence of the specific semiconductor properties on the device performance and device characteristics, we consider two magnetic superlattices based on semiconductors having entirely different Lande g-factor: GaAs and InSb. Although slightly more efficient spin-inversion devices are obtained for the GaAs semiconductor, InSb requires lower magnetic fields and its efficiency can be close to 80%.

The blood coagulation and the fibrinolytic systems of nine patients envenomed by Bothrops jararaca in São Paulo (Brazil) were studied. Five of the accidents were caused by young snakes (less than 50 cm). On admission, four patients had non-clotting and three partially-clotting blood. Fibrinogen levels were decreased due to the thrombin-like activity of the venom as expected. Consequent secondary activation of the fibrinolytic system was evident from the low levels of alpha-2-antiplasmin and the high titres of fibrin(ogen) degradation products. High titres of cross-linked fibrin fragment D (D-dimer) in seven patients together with decreased platelet counts and/or factor V, and/or factor VIII in some, suggests intrinsic thrombin formation as these factors are not consumed in the defibrinogenation induced by venom thrombin-like fractions such as Ancrod and Batroxobin. However, normal or increased levels of antithrombin III in all and normal levels of factor II in eight patients do not support this interpretation. The existence of variable concentrations of other proteins in the venom of B. jararaca such as botrocetin and thrombocytin isolated from B. jararaca and B. atrox or crotalocytin from Crotalus horridus venom should be considered. Such proteins are known to activate factors V, VIII, XIII, and platelets without affecting prothrombin (factor II) and antithrombin III. Slower recovery of the haemostatic disturbances after antivenom administration to patients bitten by young snakes suggests a more severe coagulopathy in such accidents. This is supported by clinical observations.

Non-biodegradable plastic aggregates made of polyethylene terephthalate (PET) waste from beverage containers are used as partial replacement of aggregates in mortar. Various weight fractions of sand 5%, 10%, 15% and 20% are replaced by the same weight of plastic. This paper investigates the fracture properties of the obtained composites. A reduction of the specific weight of the polymer mortars and a significant improvement of their post-peak flexural behavior are observed. The present study has shown quite encouraging results and opened new way for the recycling of PET waste in polymer mortars.

Cosmic‐ray‐induced unclear interactions are observed by emulsion chambers exposed on Mt. chacaltaya, Bolivia (5220m above sea level). We detect photons from nuclear interactions which occurred within the petroleum putch layer (1/3 nuclear mean free path), set 150 cm above the emulsion chamber.Photons of energy ≳100 GeV are detected in each event, the highest detected photon energy being 40TeV. 350 events are found to contain 4 or more photons, whose energy sums, ? Eγ, range from 5 TeV up to 500 TeV, and are adopted for analysis.Multiplicity‐, energy‐, angular‐, PT‐, and other related distributions of the photons are presented, comparison is made with the accelerator data, and discussions are given.

Events of a new type have been observed by the chacaltaya Emulsion Chamber Experiment,1,2 which can consistently be interpreted as ’’baryon’’ pair decay of a heavy intermetiate state of rest mas 20–30 GeV/c2.

Centauro‐type and Mini‐Centauro‐type events are reported and discussed. They are events in which nuclear‐active particles (i.e. hadrons which do not undergo rapid photon decays) are produced without any sign of accompanying neutral pion emission. Estimated hadron multiplicity is ∠100 for Centauro‐type and ∠15 for Mini‐Centauro‐type.Up to the present moment, 5 examples of Centauro and 13 of Mini‐Centauro have been observed in the two‐storey emulsion chambers exposed on Mt. Chacaltaya, Bolivia (5220 m above sea level).The experimental results on energy and angular distributions are in agreement with the hypothesis that this type of events occur through production and decay of a fire‐ball with a rest energy of (200∠300) GeV/c2 for Centauro and ∠30 GeV/c2 for Mini‐Centauro events.

Aluminum-based composites prepared from pure Al powder and previously Cu metallized graphite are fabricated by a solid state route and are characterized by X-ray diffraction and scanning electron microscopy in order to follow their microstructural evolution. Composites are processed using powder metallurgy technique in order to obtain cylindrical samples to carry out mechanical testing. Microstructural and mechanical characterizations reveal that, by milling, a homogeneous dispersion of insoluble particles into the Al matrix is obtained; this produces an important improvement in hardness and strength with respect to an un-milled sample. Milling intensity and particle concentration have an important effect on the mechanical properties of the synthesized composites.

Homogeneous semiconductors exhibit spin-band splitting and displacements under spatially periodic external magnetic fields, which are more clearly defined than in diluted magnetic semiconductor superlattices. We study the influence of the geometrical parameters and the spin-field interaction on the electronic transport properties. We show that by varying the external magnetic field one can easily block the transmission of either the spin-up or the spin-down electrons.

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