470 research outputs found
Terbium-activated heavy scintillating glasses
Tb-activated scintillating glasses with high Ln2O3 (Ln=Gd, Y, Lu) concentration up to 40mol% have been prepared. The effects of Ln3+ ions on the density, thermal properties, transmission and luminescence properties under both UV and X-ray excitation have been investigated. The glasses containing Gd2O3 or Lu2O3 exhibit a high density of more than 6.0g/cm3. Energy transfer from Gd3+ to Tb3+ takes place in Gd-containing glass and as a result the Gd-containing glass shows a light yield 2.5 times higher than the Y-or Lu-containing glass. The Effect of the substitution of fluorine for oxygen on the optical properties was also investigated
Improvement of CNFs/SiC nanocomposites properties obtained from different routes and consolidated by pulsed electric-current pressure sintering
The influence of the preparation route and composition on carbon nanofibers-silicon carbide (CNFs/SiC) nanocomposites' properties was studied. Nanopowders were mixed by ultrasonic dispersion or high attrition milling and the consolidation was done by pulsed electric-current pressure sintering technique. The relative density and fracture strength of high-energy attrition milled CNFs/SiC nanocomposites gradually increased with the increase of sintering temperature, from 1400 to 1800 degrees C and holding time 1 to 30 min. A chemical surface coating of CNFs with alumina precursor is proposed as a very effective way for improving the interaction between CNFs and SiC. An increase of 54% in fracture strength was achieved on the nanocomposites when the surface coating was used. As a consequence of the stronger interaction between the components, which is achieved through the use of suitable processing route and sintering parameters, and the role of nano-alumina as sintering aid improved mechanical properties was achieved. (c) 2012 Elsevier B.V. All rights reserved.This work has been carried out with the financial support of the National Plan Projects nos. MAT2006-01783 and MAT2007-30989-E and the Regional Project no. FICYT PC07-021. A. Borrell, acknowledges the Spanish Ministry of Science and Innovation for her Juan de la Cierva contract (no. JCI-2011-10498).Rocha, VG.; Borrell Tomás, MA.; Torrecillas, R.; Fernandez, A. (2012). Improvement of CNFs/SiC nanocomposites properties obtained from different routes and consolidated by pulsed electric-current pressure sintering. Materials Science and Engineering: A. 556:414-419. https://doi.org/10.1016/j.msea.2012.07.006S41441955
Experimental study of the hydrodynamic behaviour of slug flow in a horizontal pipe
This paper investigates the unsteady hydrodynamic behaviour of slug flow occurring within an air–silicone oil mixture, within a horizontal 67 mm internal diameter pipe. A series of slug flow regime experiments were performed for a range of injected air superficial velocities (0.29–1.4 m s−1) and for liquid flows with superficial velocities of between 0.05–0.47 m s−1. A pair of Electrical Capacitance Tomography (ECT) probes was used to determine: the slug translational velocities of the elongated bubbles and liquid slugs, the slug frequencies, the lengths of elongated bubbles and the liquid slugs, the void fractions within the elongated bubbles and liquid slugs. The pressure drop experienced along the pipe was measured using a differential pressure transducer cell (DP cell). A comparative analysis of the current experimental data and that previously published experimental confirms good agreement
Musculoskeletal involvement in children with gastroschisis and omphalocele
A review of 58 children with gastroschisis and 8 children with omphalocele showed 14 musculoskeletal problems in 11 children. These problems consisted of limb deformities in 6 children, spinal deformities in 4 children, and osteopenia in 3 children, with 1 of the osteopenic children developing pathological fractures. About one third (5/14) of the problems were arthrogrypotic in nature. The remainder were mild digital deformities, developmental or spondylodysplastic scolioses, and, rarely, congenital spinal deformities.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/30888/1/0000557.pd
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