3,243 research outputs found
The Effect of Barium Content on the Crystallization and Microhardness of Barium Fluormica Glass-Ceramics
Mica glass-ceramics are easily machined due to their “House-of-Cards” microstructure. Barium fluormica glass-ceramics were developed and indicated good mechanical properties. This work studies the effect of varying barium content on the crystallization and microhardness of mica glass-ceramics. Four glasses were produced with different baria contents, then converted to mica glass-ceramics using a two-step heat treatment. They were characterized using Differential Scanning Calorimetry [DSC], X-ray Diffraction [XRD], Scanning electron microscopy [SEM] and Vickers microhardness. DSC showed some formulations indicated bulk crystallisation as the dominant mechanism. XRD showed the crystallization of Barium fluorphlogopite in all the compositions with minor secondary phases. SEM showed the formation of “House-of-Cards” microstructures and with an increase in BaO content, a decrease in contrast was observed in back scattered mode. Exceptionally low hardness values (<2 GPa) were obtained for longer heat treatments/holding times and are related to the well-developed house-of-cards microstructures formed
Electron Holes and Heating in the Reconnection Dissipation Region
Using particle-in-cell simulations and kinetic theory, we explore the
current-driven turbulence and associated electron heating in the dissipation
region during 3D magnetic reconnection with a guide field. At late time the
turbulence is dominated by the Buneman and lower hybrid instabilities. Both
produce electron holes that co-exist but have very different propagation
speeds. The associated scattering of electrons by the holes enhances electron
heating in the dissipation region.Comment: 14 pages, 5 figures, submitted to GR
Data access and integration in the ISPIDER proteomics grid
Grid computing has great potential for supporting the integration of complex, fast changing biological data repositories to enable distributed data analysis. One scenario where Grid computing has such potential is provided by proteomics resources which are rapidly being developed with the emergence of affordable, reliable methods to study the proteome. The protein identifications arising from these methods derive from multiple repositories which need to be integrated to enable uniform access to them. A number of technologies exist which enable these resources to be accessed in a Grid environment, but the independent development of these resources means that significant data integration challenges, such as heterogeneity and schema evolution, have to be met. This paper presents an architecture which supports the combined use of Grid data access (OGSA-DAI), Grid distributed querying (OGSA-DQP) and data integration (AutoMed) software tools to support distributed data analysis. We discuss the application of this architecture for the integration of several autonomous proteomics data resources
Clusters in weighted macroeconomic networks : the EU case. Introducing the overlapping index of GDP/capita fluctuation correlations
GDP/capita correlations are investigated in various time windows (TW), for
the time interval 1990-2005. The target group of countries is the set of 25 EU
members, 15 till 2004 plus the 10 countries which joined EU later on. The
TW-means of the statistical correlation coefficients are taken as the weights
(links) of a fully connected network having the countries as nodes. Thereafter
we define and introduce the overlapping index of weighted network nodes. A
cluster structure of EU countries is derived from the statistically relevant
eigenvalues and eigenvectors of the adjacency matrix. This may be considered to
yield some information about the structure, stability and evolution of the EU
country clusters in a macroeconomic sense.Comment: 6 pages, 8 figures, 1 table, 17 references, submitted to Physica A;
proceedings of APFA
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