Metocean regional models using TELEMAC

Hydrodynamic

Modeling the world oceans with TELEMAC

Hydrodynamic

High-Energy sources before INTEGRAL -- INTEGRAL reference catalog --

We describe the INTEGRAL reference catalog which classifies previously known bright X-ray and gamma-ray sources before the launch of INTEGRAL. These sources are, or have been at least once, brighter than ~1 mCrab above 3 keV, and are expected to be detected by INTEGRAL. This catalog is being used in the INTEGRAL Quick Look Analysis to discover new sources or significantly variable sources. We compiled several published X-ray and gamma-ray catalogs, and surveyed recent publications for new sources. Consequently, there are 1122 sources in our INTEGRAL reference catalog. In addition to the source positions, we show an approximate spectral model and expected flux for each source, based on which we derive expected INTEGRAL counting rates. Assuming the default instrument performances and at least ~10^5 sec exposure time for any part of the sky, we expect that INTEGRAL will detect at least ~700 sources below 10 keV and ~400 sources above 20 keV over the mission life.Comment: Accepted to A&A Letter INTEGRAL special issu

Decellularised tissues obtained by a CO2-philic detergent and supercritical CO2

Tissue decellularisation has gained much attention in regenerative medicine as an alternative to synthetic materials. In decellularised tissues, biological cues can be maintained and provide cellular environments still unmet by synthetic materials. Supercritical CO2 (scCO2 ) has recently emerged as a promising alternative decellularisation technique to aggressive detergents; in addition, scCO2 provides innate sterilisation. However, to date, decellularisation with scCO2 is limited to only a few tissue types with low cellular density. In the current study, a scCO2 technique to decellularise high density tissues, including articular cartilage, tendon and skin, was developed. Results showed that most of the cellular material was removed, while the sample structure and biocompatibility was preserved. The DNA content was reduced in cartilage, tendon and skin as compared to the native tissue. The treatment did not affect the initial tendon elastic modulus [reduced from 126.35 ± 9.79 MPa to 113.48 ± 8.48 MPa (p 〉 0.05)], while it reduced the cartilage one [from 12.06 ± 2.14 MPa to 1.17 ± 0.34 MPa (p 〈 0.0001)]. Interestingly, cell adhesion molecules such as fibronectin and laminin were still present in the tissues after decellularisation. Bovine chondrocytes were metabolically active and adhered to the surface of all decellularised tissues after 1 week of cell culture. The developed method has the potential to become a cost-effective, one-step procedure for the decellularisation of dense tissues

Testing TELEMAC-2D suitability for tsunami propagation from source to near shore

When a tsunami has a large source area it may be the case that important wavelengths of the resulting tsunami wave are in the shallow water domain (i.e. wavelength is greater than 20 times the water depth). In this case TELEMAC-2D should be suitable. If shorter wavelengths are important then the best approach could be to use TELEMAC-3D non-hydrostatic. TELEMAC-2D should be tested for ability to model wave propagation correctly as well as diffraction and refraction phenomena. In this case, it is not expected that the inundation behaviour will be represented in the same model as the propagation to near shore is modelled using the wave equation formulation in TELEMAC-2D and the inundation phase (if required) will use the finite volume (kinetic scheme) in TELEMAC-2D. So it is important to find analytical or laboratory test cases that are within the shallow water equations’ limit of validity. Some such test cases have been identified and the performance of TELEMAC-2D in comparison is presented in this paper

Analysis of alpha Centauri AB including seismic constraints

Detailed models of alpha Cen A and B based on new seismological data for alpha Cen B by Carrier & Bourban (2003) have been computed using the Geneva evolution code including atomic diffusion. Taking into account the numerous observational constraints now available for the alpha Cen system, we find a stellar model which is in good agreement with the astrometric, photometric, spectroscopic and asteroseismic data. The global parameters of the alpha Cen system are now firmly constrained to an age of t=6.52+-0.30 Gyr, an initial helium mass fraction Y_i=0.275+-0.010 and an initial metallicity (Z/X)_i=0.0434+-0.0020. Thanks to these numerous observational constraints, we confirm that the mixing-length parameter alpha of the B component is larger than the one of the A component, as already suggested by many authors (Noels et al. 1991, Fernandes & Neuforge 1995 and Guenther & Demarque 2000): alpha_B is about 8% larger than alpha_A (alpha_A=1.83+-0.10 and alpha_B=1.97+-0.10). Moreover, we show that asteroseismic measurements enable to determine the radii of both stars with a very high precision (errors smaller than 0.3%). The radii deduced from seismological data are compatible with the new interferometric results of Kervella et al. (2003) even if they are slightly larger than the interferometric radii (differences smaller than 1%).Comment: 13 pages, 9 figures, accepted for publication in A&

Biodegradable polylactide/hydroxyapatite nanocomposite foam scaffolds for bone tissue engineering applications

Supercritical carbon dioxide processing of poly--lactide (PLLA)/hydroxyapatite (nHA) nanocomposites was investigated as a means to prepare foams suitable as scaffolds in bone tissue engineering applications. For given foaming parameters, addition of nHA to the PLLA gave reduced cell sizes and improved homogeneity in the size distribution, but did not significantly affect the degree of crystallinity, which remained of the order of 50 wt% in all the foams. The compressive modulus and strength were primarily influenced by the porosity and there was no significant reinforcement of the matrix by the nHA. The mechanical properties of the foams were nevertheless comparable with those of trabecular bone, and by adjusting the saturation pressure and depressurization rate it was possible to generate porosities of about 85 %, an interconnected morphology and cell diameters in the range 200-400 mu m from PLLA containing 4.17 vol% nHA, satisfying established geometrical requirements for bone replacement scaffolds

Pre- and Post-Transition Behavior of Shear Thickening Fluids in oscillating Shear

The dynamic shear-thickening behavior of concentrated colloidal suspensions of fumed silica in polypropylene glycol has been investigated. Dynamic frequency sweeps showed that, for any given solids concentration, the complex viscosity at different imposed strain amplitudes followed a unique power-law-type behavior up to the onset of strain thickening. Moreover, similar behavior was also observed in the post-transition state, i.e., the viscosities again superimposed at frequencies beyond the transition frequency. In an attempt to develop a parametric description of this behavior, both the Delaware–Rutgers rule and the concept of a critical shear stress for the onset of shear thickening in steady-state experiments were considered. However, neither approach could account for the observed trends over the entire range of strains and frequency investigated. Plots of the critical shear strains for the onset and the end-point of the transition as a function of frequency were, therefore, used to describe the state of the suspensions for an arbitrary combination of strain and frequency. Finally, Fourier transform (FT) rheology was used to evaluate the extent of non-linearity in the response of the suspensions to dynamic shear, and it was shown that the observed behavior was not significantly influenced by wall slip at the tool–specimen interface

Single-stage sealing of ceramic tiles by means of high power diode laser radiation

An investigation has been carried out using a 60 W high power diode laser (HPDL) to determine the feasibility of sealing the void between adjoining ceramic tiles with a specially developed grout material. A single-stage process has subsequently been devised using a new grout material which consists of two distinct components: a crushed ceramic tile mix substrate and a glazed enamel surface; the crushed ceramic tile mix provides a tough, inexpensive bulk substrate, whilst the enamel provides an impervious surface glaze. HPDL processing has resulted in crack and porosity free seals produced in normal atmospheric conditions. The single-stage grout is simple to formulate and easy to apply. Tiles were successfully sealed with power densities as low as 750 W/cm2 and at rates of up to 420 mm/min. Bonding of the enamel to the crushed ceramic tile mix was identified as being primarily due to van der Waals forces and, on a very small scale, some of the crushed ceramic tile mix material dissolving into the glaze