206 research outputs found
524 THE EFFECT OF PULSED ELECTROMAGNETIC FIELDS ON PHYSICAL FUNCTION MEASURED BY WOMAC OSTEOARTHRITIS INDEX IN PATIENTS WITH KNEE OSTEOARTHRITIS -A PILOT STUDY
The sintering behavior of close-packed spheres
The sintering behavior and microstructural evolution of a powder compact is influenced strongly by initial properties, such as the relative density, the particle and pore size distribution, and the powder packing. While the influence of the former parameters on the microstructural evolution has been investigated in some detail, the impact of the initial packing of the powder has been mostly overlooked. However, research has shown that the sintering behavior of a powder can be significantly improved if the powder is regularly packed.
This has been shown for monodisperse spherical TiO2 particles [1], which sintered 10 times faster and exhibited almost no grain growth compared to ordinary TiO2. Similar observations has been made for homogeneously packed Al2O3 [2], SiO2 [3], as well as a number of other materials [4]. Monodispersed spherical TiO2 particles have been shown to order in face-centered cubic (fcc) arrays, while the SiO2 powder forms stacked planes of hexagonal close-packed (hcp) particles. Close packing of monodispersed silica has also been observed [5]. Sintering of two-dimensional close packing cylinders has also been demonstrated experimentally [6–8] and numerically modeled [9,10], and the sintering of particle clusters in three dimensions has also been studied [11]
Synthesis of CdS and CdSe nanocrystallites using a novel single-molecule precursors approach
The synthesis of CdS and CdSe nanocrystallites using the thermolysis of several dithioor
diselenocarbamato complexes of cadmium in trioctylphosphine oxide (TOPO) is reported.
The nanodispersed materials obtained show quantum size effects in their optical spectra
and exhibit near band-edge luminescence. The influence of experimental parameters on
the properties of the nanocrystallites is discussed. HRTEM images of these materials show
well-defined, crystalline nanosized particles. Standard size fractionation procedures can
be performed in order to narrow the size dispersion of the samples. The TOPO-capped CdS
and CdSe nanocrystallites and simple organic bridging ligands, such as 2,2¢-bipyrimidine,
are used as the starting materials for the preparation of novel nanocomposites. The optical
properties shown by these new nanocomposites are compared with those of the starting
nanodispersed materials
Kepler Eclipsing Binary Stars. Vii. The Catalog Of Eclipsing Binaries Found In The Entire Kepler Data Set
The Kepler mission has provided unprecedented, nearly continuous photometric data of ~200,000 objects in the ~105 deg2 field of view (FOV) from the beginning of science operations in May of 2009 until the loss of the second reaction wheel in May of 2013. The Kepler Eclipsing Binary Catalog contains information including but not limited to ephemerides, stellar parameters, and analytical approximation fits for every known eclipsing binary system in the Kepler FOV. Using target pixel level data collected from Kepler in conjunction with the Kepler Eclipsing Binary Catalog, we identify false positives among eclipsing binaries, i.e., targets that are not eclipsing binaries themselves, but are instead contaminated by eclipsing binary sources nearby on the sky and show eclipsing binary signatures in their light curves. We present methods for identifying these false positives and for extracting new light curves for the true source of the observed binary signal. For each source, we extract three separate light curves for each quarter of available data by optimizing the signal-to-noise ratio, the relative percent eclipse depth, and the flux eclipse depth. We present 289 new eclipsing binaries in the Kepler FOV that were not targets for observation, and these have been added to the catalog
Structures and Properties of Newton Black Films Characterized Using Molecular Dynamics Simulations
The Catalina Surveys Periodic Variable Star Catalog
We present ~47,000 periodic variables found during the analysis of 5.4
million variable star candidates within a 20,000 square degree region covered
by the Catalina Surveys Data Release-1 (CSDR1). Combining these variables with
type-ab RR Lyrae from our previous work, we produce an on-line catalog
containing periods, amplitudes, and classifications for ~61,000 periodic
variables. By cross-matching these variables with those from prior surveys, we
find that > 90% of the ~8,000 known periodic variables in the survey region are
recovered. For these sources we find excellent agreement between our catalog
and prior values of luminosity, period and amplitude, as well as
classification.
We investigate the rate of confusion between objects classified as contact
binaries and type-c RR Lyrae (RRc's) based on periods, colours, amplitudes,
metalicities, radial velocities and surface gravities. We find that no more
than few percent of these variables in these classes are misidentified. By
deriving distances for this clean sample of ~5,500 RRc's, we trace the path of
the Sagittarius tidal streams within the Galactic halo. Selecting 146
outer-halo RRc's with SDSS radial velocities, we confirm the presence of a
coherent halo structure that is inconsistent with current N-body simulations of
the Sagittarius tidal stream. We also find numerous long-period variables that
are very likely associated within the Sagittarius tidal streams system.
Based on the examination of 31,000 contact binary light curves we find
evidence for two subgroups exhibiting irregular lightcurves. One subgroup
presents significant variations in mean brightness that are likely due to
chromospheric activity. The other subgroup shows stable modulations over more
than a thousand days and thereby provides evidence that the O'Connell effect is
not due to stellar spots.Comment: Accepted ApJS, 43 pages, 9 tables, 44 figures (some at reduced
resolution
4MOST Scientific Operations
The 4MOST instrument is a multi-object spectrograph that will address
Galactic and extragalactic science cases simultaneously by observing targets
from a large number of different surveys within each science exposure. This
parallel mode of operation and the survey nature of 4MOST require some distinct
4MOST-specific operational features within the overall operations model of ESO.
The main feature is that the 4MOST Consortium will deliver, not only the
instrument, but also contractual services to the user community, which is why
4MOST is also described as a facility. This white paper concentrates on
information particularly useful to answering the forthcoming Call for Letters
of Intent.Comment: Part of the 4MOST issue of The Messenger, published in preparation of
4MOST Community Workshop, see http://www.eso.org/sci/meetings/2019/4MOST.htm
Meeting of the Ecosystem Approach Correspondence Group on on Pollution Monitoring (CorMon Pollution)
In accordance with the UNEP/MAP Programme of Work adopted by COP 21 for the biennium 2020-2021, the United Nations Environment Programme/Mediterranean Action Plan-Barcelona Convention Secretariat (UNEP/MAP) and its Programme for the Assessment and Control of Marine Pollution in the Mediterranean (MED POL) organized the Meeting of the Ecosystem Approach Correspondence Group on Pollution Monitoring (CorMon on Pollution Monitoring). The Meeting was held via videoconference on 26-27 April 2021.
2. The main objectives of the Meeting were to:
a) Review the Monitoring Guidelines/Protocols for IMAP Common Indicator 18, as well as the Monitoring Guidelines/Protocols for Analytical Quality Assurance and Reporting of Monitoring Data for IMAP Common Indicators 13, 14, 17, 18 and 20;
b) Take stock of the state of play of inter-laboratory testing and good laboratory practice related to IMAP Ecological Objectives 5 and 9;
c) Analyze the proposal for the integration and aggregation rules for IMAP Ecological Objectives 5, 9 and 10 and assessment criteria for contaminants and nutrients;
d) Recommend the ways and means to strengthen implementation of IMAP Pollution Cluster towards preparation of the 2023 MED Quality Status Report
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