1,600 research outputs found
Profile of author B.J. Morrison of Bar Harbor, plus a review of her most recent
No full textProfile of author B.J. Morrison of Bar Harbor, plus a review of her most recent novel, The Martini Effect
Competitive segregation of gallium and indium at heterophase Cu–MnO interfaces studied with transmission electron microscopy
Full text linkThis paper concentrates on the possible segregation of indium and gallium and competitive segregation of gallium and indium at atomically flat parallel {111}-oriented Cu–MnO interfaces. The segregation of gallium at Cu–MnO interfaces after introduction of gallium in the copper matrix of internally oxidized Cu–1 at.%Mn could be hardly detected with energy-dispersive spectrometry in a field emission gun transmission electron microscope. After a heat treatment to dissolve indium in the copper matrix, gallium has a weak tendency to segregate, that is 2.5 at.% Ga per monolayer at the interface compared with 2 at.% in the copper matrix. The striking result is that this gallium segregation is observable because it does not occur at the metal side of the interface but in the first two monolayers at the oxide side. Using the same heat treatment as for introducing indium in the sample, but without indium present, gallium segregates strongly at the oxide side of the Cu–MnO interface with a concentration of about 14.3 at.% in each monolayer of the two. In contrast, the presence of gallium has no influence on the segregation of indium towards Cu–MnO interfaces, because the outermost monolayer at the metal side of the interface contains 17.6 at.% In, that is similar to previously found results. This leads to the intriguing conclusions, firstly, that, in contrast with antimony and indium, gallium segregates at the oxide side of the interface and, secondly, that the presence of indium strongly hampers gallium segregation. The results from analytical transmission electron microscopy on gallium segregation are supported by high-resolution transmission electron microscopy observations.
Groeikinetiek en morfologische ontwikkeling van oxidelagen op ?-ijzer en ?-ijzernitride bij 573 K en 673 K
No full textTechnische MateriaalwetenschappenApplied Science
Inwendige spanningen en spanningsgradiënten in "CVD" lagen van titaannitride op molybdeen: Interpretatie van röntgendiffraktie-metingen en vergelijking met modelberekeningen
No full textTechnische MateriaalwetenschappenMechanical, Maritime and Materials Engineerin
IJzer-Stikstof Fasen: terhmodynamica, lange-afstands orde en oxidatie gedrag
No full textMechanical Maritime and Materials Engineerin
MV Ocean Endeavour cruise 13 Oct-06 Nov 2005. Seabed environmental survey of Angola Blocks 18 and 31
No full textThis cruise was carried out on behalf of BP Angola and comprised a seabed environmentalsurvey of Angola Blocks 18 and 31 (bathyal SE Atlantic). Seabed sampling was undertaken byMegacorer to provide samples for macrobenthos, hydrocarbon, heavy metal and particle sizeanalysis. Seabed photography (still and video) was undertaken with the NOC WASP vehicle.Baited, time-lapse camera deployments were undertaken using the BP ROBIO system(Oceanlab, Aberdeen). The survey spanned water depths of 1300-2050m over the AngolanMargin and included studies in and around seabed pockmarks and salt diapirs. Someindications of fluid flow and chemosynthetic communities were encountered.Should you wish to consult or cite this report please contact the author directly (Brian Bett,[email protected], +44 (0)23 80596355)
The Effect Of Error Correcting Coding On Indoor Wireless Communications Systems In The 20 - 60 GHz Region
No full textAs a follow-up of the literature study ’An Overview Of Indoor Wireless Communications Systems In Ilie 20 - 60 GHz Region’, published by B.J. Bout jand W.A. Schouten in December 1992, a further study has been performed to investigate the effect of Forward Error Correcting Coding on Indoor Wireless Communications Systems. This has been done by calculating the average fade- and non-fade duration as a function of the frequency and the Signal To Noise ratio. These results are conveyed to a Bit Error Probability. After that, the same calculations are done for the same channel, but with Forward Error Correcting Coding.Electrical Engineering, Mathematics and Computer ScienceTelecommunicatie- en Verkeersbegeleidingssysteme
Transient energy growth modulation by temperature dependent transport properties in a stratified plane Poiseuille flow
No full textWe investigate the effect of temperature dependent thermal conductivity λ and isobaric specific heat c_P on the transient amplification of perturbations in a thermally stratified laminar plane Poiseuille flow. It is shown that for decreasing thermal conductivity the maximum transient energy growth is amplified with respect to the λ=1 case, while the opposite occurs for increasing λ. A reversed mechanism is induced by a variable c_p. Substantial maximum growth enhancement/suppression is found in the range of Prandtl numbers Pr which encompasses most fluids of practical interest. The relative growth modulation shows an optimum Pr under spanwise perturbations. For energy amplifying property distributions a speed-up of the transient to reach the maximum energy growth is observed at low Pr, while a slow-down is found at large Pr. The opposite is true when the property variations suppress the growth of perturbations
Interim report on the seabed environmental survey of Angola Blocks 18 and 31 (MV Ocean Endeavour cruise 2005)
No full textThis report is based on initial (at sea) observations of the seabed environment and fauna of Angola Blocks 18 and 31 as assessed during the MV Ocean Endeavour environmental survey (13 Oct-06 Nov, 2005). The report draws on the appearance and other physical characteristics of core samples and on photographic observations of the seafloor from deployments of the NOCS WASP system and the BP ROBIO lander. The megabenthos and fish populations appear to be consistent with a quiescent, fine-sedimented, bathyal region. No living cold seep (or comparable) communities were encountered during the survey. However, site ME1 (Block 31, large pockmark) has cemented sediments, both within the sediment column and at the sediment surface, and the fragmented shell remains of what appear to be large cold seep mussels; an extant community may be present in this vicinity. Other bivalve molluscs (both living and dead) of possible chemosynthetic nature were recovered from other sites (Block 31, on the periphery of diapiric features).Should you wish to consult or cite this report please contact the author directly (Brian Bett, [email protected], +44 (0)23 80596355).<br/
Monte Carlo simulations of phase transformations caused by nucleation and subsequent anisotropic growth: Extension of the Johnson-Mehl-Avrami-Kolmogorov theory
No full textMonte Carlo (MC) simulations of isothermal phase transformations were performed based on a temperature- and time-dependent nucleation rate and a temperature-dependent and time-independent anisotropic growth rate (linear growth). One- or two-dimensional anisotropic growth in two-dimensional space is considered and nucleation occurs randomly throughout space. The MC simulations show that parallel growth of anisotropically growing transformation products with identical convex shape can be described accurately by the kinetic theory due to Johnson, Mehl, Avrami, and Kolmogorov (JMAK), but nonparallel anisotropic growth, orthogonal in the present work, incorporating blocking up to all relevant orders leads to hard impingement that results in strong deviations from JMAK kinetics. A transparent analytical description extending on, but incorporating the JMAK theory has been developed that turns out to accurately reproduce the numerical results of all present MC simulation, leading to improved understanding of how impingement should be incorporated in JMAK theory.
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