Efeito da moagem de alta energia na microestrutura e nas propriedades magnéticas do compósito wc-10%p.Co

This work a studied the high energy milling effect in microstructure and magnetic properties of the WC-10wt.%Co composite. The composite powders were prepared by mechanical mixed and milled at 2 hours, 100 hours, 200 hours and 300 hours in planetary milling. After this process the composite were compacted in stainless steel die with cylindrical county of 10 mm of diameter, at pressure 200 Mpa and sintered in a resistive furnace in argon atmosphere at 1400 oC for 5 min. The sintered composite were cutted, inlaid, sandpapered, and polished. The microestrutural parameters of the composite was analyzed by X-ray diffraction, scanning electronic microscopy, optical microscopy, hardness, magnetic propriety and Rietveld method analyze. The results shows, with milling time increase the particle size decrease, it possibility minor temperature of sintering. The increase of milling time caused allotropic transformation in cobalt phase and cold welding between particles. The cold welding caused the formation of the particle composite. The X-ray diffraction pattern of composite powders shows the WC peaks intensity decrease with the milling time increase. The X-ray diffraction pattern of the composite sintered samples shows the other phases. The magnetic measurements detected a significant increase in the coercitive field and a decrease in the saturation magnetization with milling time increase. The increase coercitive field it was also verified with decrease grain size with milling time increase. For the composite powders the increase coercitive field it was verified with particle size reduction and saturation magnetization variation is relate with the variation of free cobalt. The Rietveld method analyze shows at milling time increase the mean crystalline size of WC, and Co-cfc phases in composite sintered sample are higher than in composite powders. The mean crystallite size of Co-hc phase in composite powders is higher than in composite sintered sample. The mean lattice strains of WC, Co-hc and Co-cfc phases in composite powders are higher than in composite sintered samples. The cells parameters of the composite powder decrease at milling time increase this effect came from the particle size reduction at milling time increase. In sintered composite the cells parameters is constant with milling time increase

Influência dos parâmetros de processo na deposição de nitreto de titânio por plasma em gaiola catódica

Titanium nitride films were grown on glass using the Cathodic Cage Plasma Deposition technique in order to verify the influence of process parameters in optical and structural properties of the films. The plasma atmosphere used was a mixture of Ar, N2 and H2, setting the Ar and N2 gas flows at 4 and 3 sccm, respectively and H2 gas flow varied from 0, 1 to 2 sccm. The deposition process was monitored by Optical Emission Spectroscopy (OES) to investigate the influence of the active species in plasma. It was observed that increasing the H2 gas flow into the plasma the luminescent intensities associated to the species changed. In this case, the luminescence of N2 (391,4nm) species was not proportional to the increasing of the H2 gas into the reactor. Other parameters investigated were diameter and number of holes in the cage. The analysis by Grazing Incidence X-Ray Diffraction (GIXRD) confirmed that the obtained films are composed by TiN and they may have variations in the nitrogen amount into the crystal and in the crystallite size. The optical microscopy images provided information about the homogeneity of the films. The atomic force microscopy (AFM) results revealed some microstructural characteristics and surface roughness. The thickness was measured by ellipsometry. The optical properties such as transmittance and reflectance (they were measured by spectrophotometry) are very sensitive to changes in the crystal lattice of the material, chemical composition and film thicknesses. Therefore, such properties are appropriate tools for verification of this process control. In general, films obtained at 0 sccm of H2 gas flow present a higher transmittance. It can be attributed to the smaller crystalline size due to a higher amount of nitrogen in the TiN lattice. The films obtained at 1 and 2 sccm of H2 gas flow have a golden appearance and XRD pattern showed peaks characteristics of TiN with higher intensity and smaller FWHM (Full Width at Half Maximum) parameter. It suggests that the hydrogen presence in the plasma makes the films more stoichiometric and becomes it more crystalline. It was observed that with higher number of holes in the lid of the cage, close to the region between the lid and the sample and the smaller diameter of the hole, the deposited film is thicker, which is justified by the most probability of plasma species reach effectively the sample and it promotes the growth of the film

Diagnóstico das espécies ativas do plasma usado em tratamentos termoquímicos do titânio

Plasma diagnostics by Optical Emission Spectroscopy were performed for electrical discharge in three gas mixture respecting the combinations z N2 y Ar x H2, z N2 y Ar x O2 e z N2 y Ar x CH4, in which the indexes z and y systematically vary from 1 to 4 and x varies from 0 to 4, every one has dimension SCCM, resulting in 80 combinations. From the all obtained spectrums, the species CH (387,1 nm), N2+ (391,4 nm), Hβ (486,1 nm), Hα (656,3 nm), Ar (750,4 nm), O (777,4 nm) e O (842,6 nm) were analyzed because of their abundance and importance on the kinetic of reaction from the plasma to surface, besides their high dependences on the gases flows. Particularly interesting z, y and x combinations were chosen in order to study the influence of active species on the surface modification during the thermochemical treatment. From the mixtures N2 Ar O2 e N2 Ar CH4 were chosen three peculiar proportions which presented luminous intensity profile with unexpected maximum or minimum values, denominated as plasma anomaly. Those plasma concentrations were utilized as atmosphere of titanium treatment maintaining constant the control parameters pressure and temperature. It has been verified a relation among luminous intensity associated to N2+ and roughness, nanohardness and O atoms diffusion into the crystalline lattice of treated titanium and it has been seen which those properties becomes more intense precisely in the higher points found in the optical profile associated to the N2+ specie. Those parameters were verified for the mixture which involved O2 gas. For the mixture which involves CH4 gas, the relation was determinate by roughness, number of nitrogen and carbon atoms diffused into the titanium structure which presented direct proportionality with the luminous intensity referent to the N2+ and CH. It has been yet studied the formation of TiCN phases on the surface which presented to be essentially directly proportional to the increasing of the CH specie and inversely proportional to the increasing of the specie N2+

A rede de marcação e recaptura: o caso de borboletas do gênero heliconius

(The Mark and Recapture Network: a Heliconius case study). The current pace of habitat destruction, especially in tropical landscapes, has increased the need for understanding minimum patch requirements and patch distance as tools for conserving species in forest remnants. Mark recapture and tagging studies have been instrumental in providing parameters for functional models. Because of their popularity, ease of manipulation and well known biology, butterflies have become model in studies of spatial structure. Yet, most studies on butterflies movement have focused on temperate species that live in open habitats, in which forest patches are barrier to movement. This study aimed to view and review data from mark-recapture as a network in two species of butterfly (Heliconius erato and Heliconius melpomene). A work of marking and recapture of the species was carried out in an Atlantic forest reserve located about 20km from the city of Natal (RN). Mark recapture studies were conducted in 3 weekly visits during January-February and July-August in 2007 and 2008. Captures were more common in two sections of the dirt road, with minimal collection in the forest trail. The spatial spread of captures was similar in the two species. Yet, distances between recaptures seem to be greater for Heliconius erato than for Heliconius melpomene. In addition, the erato network is more disconnected, suggesting that this specie has shorter traveling patches. Moving on to the network, both species have similar number of links (N) and unweighed vertices (L). However, melpomene has a weighed network 50% more connections than erato. These network metrics suggest that erato has more compartmentalized network and restricted movement than melpomene. Thus, erato has a larger number of disconnected components, nC, in the network, and a smaller network diameter. The frequency distribution of network connectivity for both species was better explained by a Power-law than by a random, Poissom distribution, showing that the Power-law provides a better fit than the Poisson for both species. Moreover, the Powerlaw erato is much better adjusted than in melpomene, which should be linked to the small movements that erato makes in the network

Ecologia do fitoplâncton impactado por cultivo de tilápia do Nilo, oreochromis niloticus, em tanques-rede no açude Ministro João Alves, Parelhas, Rio Grande do Norte

The dams are limnic ecosystems of great importance for its multiple uses, among them, water supply for the public and to culture of artisanal fish are most relevant. The aim of the present study is to evaluate the physical-chemical characteristics and the phytoplankton community in two chosen sites (Point 1 littoral zone of point source; Point 2 pelagic zone of non-point source) of the Minister João Alves dam, which is also known as Boqueirão de Parelhas/RN. This represents the spatial distribution of the phytoplankton species in order to understand any possible alterations of the water quality and the phytoplankton composition in relation to the water quality originating from the impact of the tilapia, Oreochromis niloticus, culture. The study period also encompasses temporal variations exhibited in two seasons of an annual cycle, one during the dry season (Oct, Nov and Dec of 2008 and Jan of 2009), and the other rainy season (Mar, Apr, May and June of 2008) to extend the observation. The physicalchemical parameters, such as pH, temperature, electrical conductivity, concentration of dissolved oxygen were measured in situ and the values of the inorganic nutrients (nitrate, ammonium and orto-phosfato) and chlorophyll in the laboratory. The quali-quantitative analyses of the phytoplankton had been carried through sedimentation technique and the enumeration of the random of 400 cells, colonies and filaments counted using Sedgwick-Rafter counting chamber. The results of pH varied widely from the acidic to alkaline range with the minimum of 5.8 (± 0.8) and the maximum of 9.2 (± 0.7-0.8), at point 1 and 2. The dissolved oxygen content was higher in the rainy period than that in the dry period. The maximum electrical conductivity was of 1409 μScm-1 in point 1 and 431 minim of μScm-1, in point 2. There was a considerable alteration in the levels of inorganic nutrients such as nitrate-nitrogen, ammoniacal nitrogen and orthophosphate during the two cycles of study period. Phytoplankton assemblages presented a picture of alternate dominance among species Cyanobacteria, Bacillariophyceae and Chlorophyceae. The trophic state index diagnosed to the category of mesotrophic, which is based on the values of chlorophyll, total phosphorus and Secchi-disc measurements. The wind driven turbulence of the water column and the fresh inflow of water (flushing and dilution) during rainy season acted as constraint and did-not allow an exaggerated growth of the species of cyanobacteria. On the basis of the present we conclude that the culture of tilapias in cage-culture fails to produce pollution load that could compromise the quality of the water of the dam, probably be due to small dimension of the culture in relation to the size, volume of the water and the reservoir capacity support its own environment

Avaliação do desenvolvimento neuropsicomotor em crianças na rede básica de saúde utilizando o teste de Denver II: identificação de fatores de risco materno

Alterations in the neuropsychomotor development of children are not rare and can manifest themselves with varying intensity at different stages of their development. In this context, maternal risk factors may contribute to the appearance of these alterations. A number of studies have reported that neuropsychomotor development diagnosis is not an easy task, especially in the basic public health network. Diagnosis requires effective, low-cost, and easy - to-apply procedures. The Denver Developmental Screening Test, first published in 1967, is currently used in several countries. It has been revised and renamed as the Denver II Test and meets the aforementioned criteria. Accordingly, the aim of this study was to apply the Denver II Test in order to verify the prevalence of suspected neuropsychomotor development delay in children between the ages of 0 and 12 months and correlate it with the following maternal risk factors: family income, schooling, age at pregnancy, drug use during pregnancy, gestational age, gestational problems, type of delivery and the desire to have children. For data collection, performed during the first 6 months of 2004, a clinical assessment was made of 398 children selected by pediatricians and the nursing team of each public health unit. Later, the parents or guardians were asked to complete a structured questionnaire to determine possible risk indicators of neuropsychomotor development delay. Finally the Denver II Developmental Screening Test (DDST) was applied. The data were analyzed together, using Statistical Package for Social Science (SPSS) software, version 6.1. The confidence interval was set at 95%. The Denver II Test yielded normal and questionable results. This suggests compromised neuropsychomotor development in the children examined and deserves further investigation. The correlation of the results with preestablished maternal risk variables (family income, mother s schooling, age at pregnancy, drug use during the pregnancy and gestational age) was strongly significant. The other maternal risk variables (gestational problems, type of delivery and desire to have children) were not significant. Using an adjusted logistic regression model, we obtained the estimate of the greater likelihood of a child having suspected neuropsychomotor development delay: a mother with _75 4 years of schooling, chronological age less than 20 years and a drug user during pregnancy. This study produced two manuscripts, one published in Acta Cirúrgica Brasileira , in which an analysis was performed of children with suspected neuropsychomotor development delay in the city of Natal, Brazil. The other paper (to be published) analyzed the magnitude of the independent variable maternal schooling associated to neuropsychomotor development delay, every 3 months during the first twelve months of life of the children selected.. The results of the present study reinforce the multifactorial characteristic of development and the cumulative effect of maternal risk factors, and show the need for a regional policy that promotes low-cost programs for the community, involving children at risk of neuropsychomotor development delay. Moreover, they suggest the need for better qualified health professionals in terms of monitoring child development. This was an inter- and multidisciplinary study with the integrated participation of doctors, nurses, nursing assistants and professionals from other areas, such as statisticians and information technology professionals, who met all the requirements of the Postgraduate Program in Health Sciences of the Federal University of Rio Grande do Norte

Caracteristicas sodiodemogáficas, ocupacionais e de saúde na avaliação da qualidade de vida de professores da rede municipal de Natal/RN

Objetivo: Analisar as características sociodemográficas, ocupacionais e de saúde clínica/comportamental, e o impacto desses fatores na avaliação da qualidade de vida de professores da rede municipal de Natal/RN. Métodos: Estudo descritivo-analítico com corte transversal e amostra de 242 docentes. Foram utilizados os questionários Whoqol-breve e nórdico, além de questões referentes ao trabalho do Job Content Questionnaire (JCQ). Os dados foram submetidos à análise estatística com nível de significância p<0,05, sendo utilizada a regressão logística binária, para análise de fatores hierarquicamente agrupados. Resultados: O domínio físico apresentou maior comprometimento entre os professores com trabalho de alta exigência (p=0,043), com mais de 02 diagnósticos de doenças (p < 0,001), atividade física inadequada (p= 0,001) e com sintomas osteomusculares (p=0.025); o domínio psicológico entre os docentes com trabalho de alta exigência (p=0,043), com carga horária maior que 28 horas semanais (p=0,034), com mais de 02 doenças (p=0,012) e que praticavam atividade física inadequadamente (p< 0,001); o de relações sociais com tempo de trabalho inferior/igual a 18 anos (p=0,036) e que residiam em bairro diferente do que trabalhavam (p=0,027); e, por último, o domínio meio ambiente apresentou maior comprometimento entre os docentes com carga horária superior a 28 horas semanais (p=0,025), que exerciam a atividade com tempo inferior/igual a 18 anos (p=0,013) e com sintomas osteomusculares (p= 0,002). Conclusões: Os professores apresentaram uma avaliação comprometida da qualidade de vida e do seu estado de saúde, tendo as atividades laborais desenvolvidas por esse grupo de trabalhadores um impacto importante sobre os resultados demonstrados. Tais achados podem comprometer a efetivação da proposta das escolas promotora de saúde

Excesso de peso em região do nordeste brasileiro: contraste entre escolares de rede pública e privada de ensino

The prevalence of obesity has been increased in the last three decades. It is already considered as epidemic by the World Health Organization and reaches around 300 million people worldwide. The weight gain in all ages is related to a sedentary way of life and hyper caloric food ingestion at the modern society. Obesity is a chronic disease and leads to high blood pressure, diabetes, cardiovascular diseases and cancer. The aim of this study was to evaluate the prevalence of weight excess among student in Natal schools and to analyze its association with age, gender, school category and geographic localization in city zones. This was a transversal study which enrolled 1927 children. 1084 of these were between 6 and 8 years-old (group 1) and 843 were 9 to 10 years-old (group 2). 895 of the total children studied in private schools and 1032 studied in public schools. 33,6% of the students had body mass index equal or above the 85th percentile and were considered as having weight excess. There was no statistical difference in this prevalence considering neither gender nor age. The weight excess prevalence in private schools was 54,5% and in public ones was 15,6% (p<0,01; OR=6,49). Weight excess was also more prevalent in the south and east city zones (41,3%) which have better quality of life index than in the north and west zones (28,4%) (p<0,01). In conclusion, the weight excess prevalence among students is found to be high in Natal and programs of intervention and prevention of obesity are necessary. The higher prevalence in private schools as in the wealthier city zones reflects the link between obesity and high socioeconomic level found in countries in developing. This was an interdisciplinary work with participation of epidemiology, child nutrition and pediatric endocrinology following the recommendations and principles of the Post graduation Program in Health Sciences of the Federal University of Rio Grande do Norte

Marcas dermatoglíficas, Antropometria e as qualidades físicas básicas dos escolares da rede municipal da cidade de Manaus

The objective of this study of comparative descriptive character went aimed at to analyze the characteristics dermatoglyphics, anthropometrics and the basic physical qualities, in 180 selected scholars in a stratified way, distributed like this: 10 year-old boys = 32; 09 years = 32; 08 years = 32; 10 year-old girls = 28; 09 years = 28; 08 years = 28), studying the fundamental teaching of the School Good Municipal Hope, located in the area east, in the Neighborhood of the Crowned, in the city of Manaus, Amazon. For identification of the dermatoglyphics characteristics collected, was the fingerprints; for evaluation of the corporal mass, height and IMC, they were used a digital scale with an estadiometer of the mark Filizola. The tests: to sit down and to reach flexibility); Horizontal Impulse or I jump in distance stopped (force of inferior members); Flex and extension of the trunk (it Forces abdominal); Flexion and extension of the arms in suspension in the bar (Force of superior members); 30 meters (Speed) and 9 minutes (Resistance applied aerobic) was to evaluate the basic physical qualities. The results demonstrated that differences didn't exist among the goods, in most of the studied variables, and the existent differences among the ages of 8, 9 and 10 years, they demonstrate a normality tendency in the infantile development

Compartimentação fisiográfica para análise ambiental do potencial erosivo a partir das propriedades da rede de drenagem

O presente trabalho teve como objetivo compartimentar a sub-bacia do Baixo Rio Piracicaba - SP, em unidades homogêneas quanto à potencialidade à erosão visando a subsidiar o gerenciamento ambiental. A importância desta pesquisa concentra-se no intenso desenvolvimento dos processos erosivos na área em foco e na sua importância socioeconômica em níveis estadual e nacional. O procedimento adotado para atingir o objetivo foi a análise da rede de drenagem e dos lineamentos obtidos pelas imagens TM/Landsat-5. O resultado obtido foi a divisão da área em quatro compartimentos quanto à potencialidade à erosão: muito alta, alta, média e baixa. Concluiu-se que a área estudada é heterogênea, com regiões sujeitas a diferentes intensidades de processos erosivos e que a sistemática adotada se mostrou eficiente para caracterizar as compartimentações fisiográficas da potencialidade erosiva, e essas compartimentações podem e devem ser utilizadas como ponto de partida para estudos ambientais e de utilização do território, em consonância com o desenvolvimento sustentável.

Um modelo analítico da qualidade da dieta de adolescentes estudantes da rede publica de ensino de Natal, Brasil

Conselho Nacional de Desenvolvimento Científico e Tecnológico

Desempenho produtivo de Pseudoplatystoma corruscans estocados em sistemas de criação: semi-intensivo (viveiro escavado) e intensivo (tanque-rede)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Custos e rentabilidade da produção de juvenis de tilápia-do-nilo em tanques-rede utilizando-se diferentes densidades de estocagem

Neste trabalho foi realizada a análise econômica da produção de juvenis de tilápia-do-nilo em tanques-rede utilizando-se diferentes densidades de estocagem. O experimento foi desenvolvido em área aquícola, em delineamento de blocos casualizados, com quatro densidades de estocagem (100, 200, 300 e 400 peixes m-3), avaliadas com seis repetições, em dois períodos de criação: de março a abril de 2005 (52 dias - peso inicial de 43,08 ± 2,98 g e peso final de 262,14 ± 47,86 g) e de março a abril de 2006 (58 dias - peso inicial de 43,16 ± 5,34 g e peso final 314,24 ± 73,30 g). Foram avaliadas as seguintes variáveis econômicas: custo da ração mais custo do juvenil dividido pela biomassa, em R$ kg-1; porcentagem do custo da ração por quilo de peixe produzido sobre o preço de venda; porcentagem do custo do juvenil por quilo de peixe produzido sobre o preço de venda e; porcentagem dos custos da ração mais do juvenil por quilo de peixe produzido sobre o preço de venda. da menor densidade de estocagem (100) para a maior (400), ocorreu diminuição no ganho de peso diário e elevação do índice de conversão alimentar aparente, mas essa redução não comprometeu a taxa de sobrevivência. Entretanto, o ganho de biomassa aumentou com o adensamento de peixes. As maiores receitas líquidas foram obtidas nas densidades de estocagem de 100 e 200 peixes m-3. Os preços não remuneraram os custos operacionais (efetivo e total) em maiores densidades (300 e 400 peixes m-3). Os melhores resultados para a produção de juvenis de tilápia-do-nilo foram obtidos com densidades de até 200 peixes m-3.

Proteína e energia na alimentação de pacus criados em tanques-rede

O objetivo neste trabalho foi avaliar o desempenho de pacus (Piaractus mesopotamicus) criados em tanques-rede e alimentados com dietas contendo níveis de proteína bruta (PB) e energia digestível (ED). Foram utilizados 3.960 peixes com 293,38 ± 5,67 g de peso inicial, distribuídos em 18 tanques-rede de 5 m³, com 220 peixes por unidade experimental (44 peixes/m³), em esquema fatorial 3 × 2, composto de três níveis de proteína bruta (25, 30 e 35%) e dois de energia digestível (3.250 e 3.500 kcal/kg). O arraçoamento foi realizado quatro vezes ao dia (às 9 h, 11h30min, 14 h e 17 h) até a saciedade aparente dos animais. Não foram observadas diferenças no ganho de peso, na taxa de sobrevivência, na conversão alimentar aparente nem na taxa de crescimento específico. No entanto, houve diferença na deposição de gordura visceral, que foi maior nos animais alimentados com as rações de maior nível energético. Também não foi observada influência dos níveis de proteína e energia da dieta nos teores de umidade, proteína bruta, matéria mineral e lipídio dos filés. Rações contendo 25% de proteína bruta e 3.250 kcal/kg de energia digestível promovem melhores resultados de desempenho.

Pré-concentração de cádmio com Saccharomyces cerevisiae e determinação em águas fluviais usando espectrometria de emissão óptica com plasma indutivamente acoplado

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