Rapid solidification and phase stability evaluation of Ti-Si-B alloys

Ti-rich Ti-Si-B alloys can be considered for structural applications at high temperatures (max. 700 degrees C), however, phase equilibria data is reported only for T = 1250 degrees C. Thus, in this work the phase stability of this system has been evaluated at 700 degrees C. In order to attain equilibrium conditions in shorter time, rapid solidified samples have been prepared and carefully characterized. The microstructural characterization of the produced materials were based on X-ray diffraction (XRD), scanning electron microscopy (SEM-BSE), high resolution transmission electron microscopy (HRTEM), High Temperature X-ray diffraction with Synchrotron radiation (XRDSR) and Differential Scanning Calorimetry (DSC). Amorphous and amorphous with embedded nanocrystals have been observed after rapid solidification from specific alloy compositions. The values of the crystallization temperature (Tx) of the alloys were in the 509-647 degrees C temperature range. After Differential Scanning Calorimetry and High Temperature X-ray Diffraction with Synchrotron radiation, the alloys showed crystalline and basically formed by two or three of the following phases: alpha Ti, Ti(6)Si(2)B; Ti(5)Si(3); Ti(3)Si and TiB. It has been shown the stability of the Ti(3)Si and Ti(6)Si(2)B phases at 700 degrees C and the proposition of an isothermal section at this temperature. (C) 2011 Elsevier B.V. All rights reserved.CNPq[142242/2007-1]FAPESP[2001/09529-7]FAPESP[2007/05206-5]FINEP[1651]Brazilian Synchrotron Light Laboratory (LNLS

Detecção ultrassonográfica do ovário fetal em loba-guará (Chrysocyon brachyurus): relato de caso

Identificaram-se, por ultrassonografia, os ovários fetais e o sexo dos fetos em uma loba-guará. Ao exame ultrassonográfico, foi possível identificar estruturas fetais e realizar medidas (relação entre diâmetro cranial e abdominal dos fetos) que indicavam idade fetal de 59 dias. Observaram-se: estruturas torácicas e abdominais formadas, diafragma, membros, estruturas do crânio definidas, coluna vertebral, medula, costelas, batimentos cardíacos normais, movimentação fetal, câmaras e valvas cardíacas, grandes vasos, rins, peristaltismo intestinal e ovários fetais. O exame ultrassonográfico foi eficaz nessa espécie, pois foi possível observar estruturas fetais para a avaliação da viabilidade fetal e, também, identificou-se a imagem ovariana em um dos fetos, mostrando-se importante para estudos de sexagem fetal.The ovaries and the gender of the fetuses in a female maned wolf (Chrysocyon brachyurus) were identified by ultrasound examination. It was possible to identify fetal structures and to determine measures, i.e., cranial and abdominal diameters and these elements indicated 59-day of fetal age. The main visualized structures were diaphragm, members, cranium, spine, marrow, ribs, cardiac chambers and valves, veins and arteries, kidneys, and fetal ovaries. Normal heartbeats and fetal and bowel movements were recorded. The ultrasound examination was an effective method in this species, since enabled the correct observation of the fetal structures as well as viability; in addition, proved to be an important method for fetal sexing determination

Niobium hydrogenation process Effect of temperature and cooling rate from the hydrogenation temperature

High-purity niobium powder can be produced via the hydrogenation and dehydrogenation processes The present work aimed at the effect of temperature and cooling rate conditions on the niobium hydrogenation process using hydrogen gas The hydrogen contents of the materials were evaluated by weight change and chemical analysis X ray diffraction (XRD) was performed to identify and determine the lattice parameters of the formed hydride phases No hydrogenation took place under isothermal conditions only during cooling of the materials Significant hydrogenation occurred in the 500 C and 700 C experiments leading to the formation of a beta NbH(x) single phase material (C) 2010 Elsevier Ltd All rights reserve

Effects of fasting and refeeding on the metabolic functions of the turtle kinosternon scorpioides (linnaeus, 1766) raised in captivity

The metabolic responses of adult and young freshwater Kinosternon scorpioides turtles raised in captivity were evaluated. Two experiments were performed: a) blood metabolite changes caused by food deprivation, and b) liver and muscle glycogen and total lipid differences after fasting and refeeding. Blood glucose concentration of young animals was susceptible to food deprivation. In both groups this metabolite decreased after 30 days of fasting. Feeding for 15 days did not recover blood glucose. Total seric proteins were not affected by food deprivation. Fasting decreased blood urea nitrogen and the highest difference was found around 30 days. Uric acid increased in young animals after 60 days of fasting. Triacylglicerol decreased after 15 days of fasting and refeeding for 15 days recovered the pre-fasting levels. Free fatty acid plasma tended to increase around 15 days of fasting. Liver glycogen decreased at day 15 of fasting, being stable thereafter while muscle glycogen decreased at a slower rate. Total liver lipid stabilized after 30 days and then decreased 70% after 60 days of fasting. Muscle lipids remained stable throughout fasting. It could be concluded that fasting of Kinosternon scorpioides led to metabolic adaptations similar to the one reported from reptiles and fish.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Quantitative ultrasound criteria for risk stratification in clinical practice: a comparative assessment

This study aimed to compare two different classifications of the risk of fracture/osteoporosis (OP) based on quantitative ultrasound (QUS). Analyses were based on data from the Epidemiological Study on the Prevalence of Osteoporosis, a cross-sectional study conducted in 2000 aimed at assessing the risk of OP in a representative sample of the Italian population. Subjects were classified into 5 groups considering the cross-classification found in previous studies; logistic regression models were defined separately for women and men to study the fracture risk attributable to groups defined by the cross-classification, adjusting for traditional risk factors. Eight-thousand six-hundred eighty-one subjects were considered in the analyses. Logistic regression models revealed that the two classifications seem to be able to identify a common core of individuals at low and at high risk of fractures, and the importance of a multidimensional assessment in older patients to evaluate clinical risk factors together with a simple, inexpensive, radiation-free device such as QUS

Quantitative ultrasound criteria for risk stratification in clinical practice: a comparative assessment.

This study aimed to compare two different classifications of the risk of fracture/osteoporosis (OP) based on quantitative ultrasound (QUS). Analyses were based on data from the Epidemiological Study on the Prevalence of Osteoporosis, a cross-sectional study conducted in 2000 aimed at assessing the risk of OP in a representative sample of the Italian population. Subjects were classified into 5 groups considering the cross-classification found in previous studies; logistic regression models were defined separately for women and men to study the fracture risk attributable to groups defined by the cross-classification, adjusting for traditional risk factors. Eight-thousand six-hundred eighty-one subjects were considered in the analyses. Logistic regression models revealed that the two classifications seem to be able to identify a common core of individuals at low and at high risk of fractures, and the importance of a multidimensional assessment in older patients to evaluate clinical risk factors together with a simple, inexpensive, radiation-free device such as QUS