In this paper, the oxidation behavior of silicon nitride with different contents of TiN was evaluated at 1400 oC for 64 hours in air. The oxidized samples were characterized by X-ray diffraction, scanning electron microscopy and energy dispersive X-ray spectroscopy. Weight gain measurements have shown that the oxidation followed a multiple-law model with linear, parabolic, and logarithmic contributions. The samples presented high weight gain at the beginning of the process followed by the formation of an amorphous silica surface layer containing Y2Ti2O7 and rutile crystals. Cracks and holes were detected on the oxide layer. The oxidation resistance of the composites was strongly influenced by the initial content of TiN.

Resumo Synadenium grantii é uma planta Euphorbiaceae comumente encontrada no Brasil, conhecida como Janaúba ou Leitosinha, e tem seu látex usado tradicionalmente para diferentes propósitos. Entretanto, não se conhece se a atividade nematicida da planta ocorre devido à ação de proteases. O presente trabalho tem como objetivo avaliar a atividade nematicida das proteases do látex de Synadenium grantii sobre Meloidogyne incognita e Panagrellus redivivus. O látex de S. grantii utilizado no presente trabalho foi coletado a partir de espécimes encontradas na Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil. O látex foi coletado em microtubos Eppendorf e imediatamente armazenado em gelo a 4 °C. Após esta extração, o látex foi congelado (-20 °C) durante 2 horas, descongelado à temperatura ambiente (25 °C) e centrifugado a 10000 g a 4 °C durante 30 minutos para a remoção de partículas e concentração das proteases. Após a centrifugação, foram realizados ensaios de atividade enzimática para saber em qual das fases as enzimas foram encontradas. O látex de S. grantii apresentou atividade de protease, mas nenhuma atividade de quitinase. Os resultados mostram que houve diferença significativa (p <0,01) entre os grupos tratados e controle, com 100% de mortalidade de Meloidogyne incognita e 72% de mortalidade média de Panagrellus redivivus. Além disso, foi demonstrado que a ação nematicida ocorreu devido à ação das proteases, uma vez que o grupo controle só foi diferenciado do tratamento pela presença das enzimas com atividade biológica.

Abstract Synadenium grantii is a Euphorbiaceae plant commonly found in Brazil, known as Janaúba or Leitosinha, whose latex is traditionally used for several purposes. However, it is not known whether the nematicidal action of this plant latex occurs due to the action of proteases. The present work aims to evaluate the nematicidal activity of proteases from Synadenium grantii latex on Meloidogyne incognita and Panagrellus redivivus. S. grantii latex used in the present study was collected from specimens found in Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil. The drained latex was collected in Eppendorf microtubes and immediately stored on ice at 4 °C. After this extraction, the latex was frozen (-20 °C) during 2 hours, thawed at room temperature (25 °C) and centrifuged at 10,000 g at 4 °C for 30 minutes to remove larger particles and concentrate the proteases. After the centrifugation, assays of enzymatic activity were performed in order to know in which of the phases the enzymes were found. S. grantii latex presented protease, but no chitinase activity. The results show that there was a significant difference (p <0.01) between the treated and control groups, with 100% mortality of Meloidogyne incognita and 72% average mortality of Panagrellus redivivus. In addition, it was demonstrated that the nematicidal action occurred due to the action of the proteases, since the control was only differentiated from the treatment by the presence of the enzymes with biological activity.

Abstract Silicon nitride is a ceramic material widely used in various structural applications at high temperatures owing to its excellent combination of mechanical and thermal properties. To increase the application of Si3N4, many researches have been developed to improve its fracture toughness and processing conditions. In this study, the sintering and microstructure of Si3N4-TiN composites, containing Al2O3 and Y2O3 as sintering aids, were studied. Samples were obtained by the conventional method of mixing powders and sintered at 1750 ºC/1 h and 1815 ºC/1 h under nitrogen atmosphere. Density values of the samples were determined by the Archimedes method, reaching values between 96.9% and 98.0% of theoretical density, with a porosity of less than 0.5%. The sintered samples were analyzed by X-ray powder diffraction and scanning electron microscopy. The results showed the materials reached high fracture toughness, low hardness and a microstructure with TiN grains dispersed in a β-Si3N4 matrix containing an amorphous intergranular phase.

Automated guided vehicles (AGVs) are widely used for transporting materials in industry and commerce. In this research, an intelligent AGV-based material-handling system was developed using a modelbased systems engineering (MBSE) approach. The core of the AGV, the controller, was designed in the system modelling language environment using Visual Paradigm software, and then implemented in the hardware. As the result, the AGV's complex tasks of material handling, navigation, and communication were successfully accomplished and tested in the real industrial environment. The developed AGV is capable of towing trolleys with a weight of up to 200kg at walking speed. The AGV can be incorporated into an intelligent material-handling system with multiple autonomous vehicles and work stations, thus providing flexibility and reconfigurability for the whole manufacturing system. Ergonomic and safety aspects were also considered in the design of the AGV. A comprehensive safety system that is compliant with industrial standards was implemented.

Die nywerheid- en handelsbedryf gebruik dikwels outomatiese begeleide voertuie. 'n Outomatiese begeleide voertuig gebaseerde materiaalhanteringsisteem is ontwikkel deur 'n modelgebaseerde benadering. Die voertuig se beheerder is ontwikkel deur gebruik te maak van Visual Paradigm sagteware en is op die hardeware geïmplementeer. Die ingewikkelde materiaalhanteringstake wat na die voertuig gestuur is, wat onder meer die hantering, navigasie en kommunikasie insluit, is suksesvol uitgevoer en getoets in 'n werklike nywerheidsomgewing. Die onwikkelde outomatiese begeleide voertuig kan waentjies met 'n massa van 200kg teen stapspoed sleep. Die outomatiesbegeleide voertuig kan by 'n intelligente materiaalhanteringsisteem, wat uit verskeie outonome voertuie en werkstasies bestaan, geïntegreer word. Dit bied dus die vermoë om die hele vervaardigingstelsel te herkonfigureer of maklik aan te pas. Ergonomiese en veiligheidsaspekte is ook oorweeg vir die ontwerp van die voertuig. 'n Omvattende veiligheidstelsel wat aan die toepaslike industriestandaarde voldoen is geïmplementeer.

RESUMOObjetivou-se com este trabalho verificar a divergência genética entre sete genótipos de frangos tipo caipira da linhagem Redbro utilizando as características de desempenho por meio de técnicas de análise multivariada. Foram utilizados 840 pintos de um dia, machos, distribuídos em delineamento inteiramente ao acaso, dos seguintes genótipos: Caboclo, Carijó, Colorpak, Gigante Negro, Pesadão Vermelho, Pescoço Pelado e Tricolor. Após a consistência dos dados, foram avaliadas as seguintes variáveis: ganho em peso médio diário, consumo de ração médio diário e conversão alimentar, para os períodos: 1 a 28, 1 a 56, 1 a 70 e 1 a 84 dias de idade; peso corporal ao nascimento, aos 28, 56, 70 e aos 84 dias de idade. O desempenho dos genótipos foi avaliado por meio da análise de variância multivariada e da função discriminante linear de Fisher, usando os testes do maior autovalor de Roy e da união-interseção de Roy para as comparações múltiplas. O estudo da divergência genética foi feito por meio da análise por variáveis canônicas e pelo método de otimização de Tocher. Os genótipos Caboclo e Gigante Negro apresentaram médias canônicas diferentes dos demais genótipos. As duas primeiras variáveis canônicas explicaram 97,41% da variação entre os genótipos. A divergência genética entre os genótipos avaliados permitiu a formação de quatro grupos com os seguintes genótipos: grupo 1 - Colorpak; grupo 2 - Pesadão Vermelho e Pescoço Pelado; grupo 3 - Carijó e Tricolor; e grupo 4 - Caboclo e Gigante Negro.

ABSTRACTThe aim of this study was to evaluate the genetic divergence among seven genotypes of alternative strain of broiler chickens of the Redbro strain using the performance characteristics using multivariate analysis. We used 840 day old male chicks, distributed in a completely randomized design, with the following genotypes: Caboclo, Carijó, Colorpak, Gigante Negro, Pesadão Vermelho, Pescoço Pelado and Tricolor. After the consistency of the data, the following variables were analyzed: average daily gain, average daily feed intake and feed conversion for the periods: 1 to 28, 1 to 56, 1 to 70 and 1 to 84 days of age, body weight at birth, at 28, 56, 70 and at 84 days old. The performance of genotypes was assessed by multivariate analysis of variance and Fisher's linear discriminant function, using the tests of the largest eigenvalue of Roy and the Roy union-intersection for multiple comparisons. The study of genetic diversity was done by canonical variate analysis and the method of Tocher. The genotypes Caboclo and Gigante Negro had different canonical averages from the other genotypes. The first two canonical variables accounted for 97.41% of the variation among genotypes. The genetic divergence between the genotypes allowed the formation of four groups with the following genotypes: group 1 - Colorpak, group 2 - Pesadão Vermelho and Pescoço Pelado; group 3 - Carijó and Tricolor, and group 4 - Caboclo and Gigante Negro.

A mastite subclínica caprina ocasiona prejuízos econômicos em decorrência do descarte, dos gastos com medidas terapêuticas e da redução da quantidade e qualidade do leite e seus derivados. Nesse estudo, 129 amostras de leite de cabra in natura, provenientes de 11 propriedades foram avaliadas pelo teste da caneca telada, California Mastitis Test (CMT), exame bacteriológico, pesquisa de Mycoplasma spp. e pela determinação dos parâmetros físico-químicos. No teste da caneca telada e no CMT, 3,1% e 4,6% das amostras foram positivas, respectivamente. No exame bacteriológico, 57,4% das amostras foram positivas e o patógeno mais frequente foi Staphylococcus coagulase negativa com 56% das cepas resistentes à penicilina e 100% de sensíveis à gentamicina. Mycoplasma spp. não foi identificado nas amostras. O diagnóstico da mastite subclínica pelo CMT e pelo exame bacteriológico diferiu de forma significativa e não houve associação entre o número de UFC/mL obtidas no exame microbiológico e o resultado do CMT (Qui-quadrado p < 0,05). Os parâmetros físico-químicos diferiram significativamente entre os rebanhos (ANOVA, Tukey-Kramer, p < 0,05) e a gordura foi o constituinte que demonstrou maior amplitude, sendo que 63,4% dos rebanhos apresentaram os valores abaixo do exigido pela legislação brasileira. Não houve associação significativa entre a presença de mastite diagnosticada pelo exame bacteriológico e os valores obtidos para os parâmetros físico-químicos (t-Student p > 0,05). Com base nos resultados obtidos, recomenda-se a associação do exame bacteriológico quando na utilização do CMT para diagnóstico da mastite subclínica caprina.

Goat mastitis causes significant economic losses due to the discarding of milk, costs of drugs and veterinary care, reducing the quantity and quality of milk and dairy products. In this study, 129 raw milk samples from 11 goat farms were investigated by the Tamis test, California mastitis test (CMT), bacteriological exam, presence of Mycoplasma spp. and physicochemical parameters. Seven (4.6%) and four samples (3.1%) were positive by CMT and Tamis test respectively. Bacteriological exam was positive from 57.4% of samples and coagulase-negative Staphylococcus was the most frequent bacteria isolated showing 56% of the strains resistant to penicillin and no resistance to gentamicin. Negative results were obtained from traditional culture as well as by PCR for Mycoplasma spp. The diagnosis of mastitis, the bacteriological exam and the CMT results differed significantly and no association was observed (chi squared, p < 0.05). Fat was the constituent with more variations and 63.4% of the herds did not meet the minimum requirement according to Brazilian government criteria for this constituent. There was no significant association between mastitis and the physicochemical parameters (t-Student, p > 0.05). The physicochemical parameters differed significantly (ANOVA, Tukey-Kramer, p < 0.05) among the herds. These results indicate the need to associate microbiological exam when the CMT is used for the diagnosis of goat mastitis.

A influência de condições halomórficas, hidromórficas e sulfato redutoras na mineralogia da fração argila e na geoquímica de três solos de mangue foi estudada no manguezal do rio Iriri. A partir de uma transeção, foram escolhidos três perfis representativos dos solos de mangue da área nos quais foram descritas as condições geoquímicas e sua conseqüência sobre a mineralogia de seus respectivos solos. A análise mineralógica (DRX e EDS) e as condições físico-químicas encontradas revelam a ocorrência de processos de piritização na área de estudo. A assembléia mineralógica está composta tanto por argilominerais alóctones (caulinitas, micas e esmectitas) como por argilominerais autóctones (micas, esmectitas e pirita). A partir de evidências provenientes da DRX e EDS, especula-se a formação de glauconita nestes solos. As condições de halomorfia e hidromorfia determinam valores de Eh e pH sob os quais elementos como Fe2+ e SO encontram-se livres na solução do solo com tendência à estabilidade da pirita (FeS2), favorecendo, portanto, o processo da piritização.

The present study evaluated the influence of halomorphic, hydromorphic, and sulfate reduction conditions on sand fraction mineralogy and on the geochemistry of three mangrove soils from the Iriri River estuary. Three representative soil profiles selected from a transect had their geochemical conditions characterized and their effects on the mineralogy of the soils were described. The mineralogical analyses (XRD and EDS) and the physicochemical (Eh and pH) conditions found indicate the occurrence of pyritization in the investigated area. The mineralogical soil assembly is composed of both allochthonous (kaolinite, mica, and smectite) and autochthonous clays (mica, smectite, and pyrite). Based on the XRD and EDS data, it is speculated the possibility of glauconite formation in these soils. The halomorphic and hydromorphic conditions determine the Eh and pH values. Under such environment Fe2+ and SO are found free the soil solution with a tendency to stabilize as pyrite (FeS2), thus favorinf the pyritization process.