Process-evaluation of tropospheric humidity simulated by general circulation models using water vapor isotopologues: 1. Comparison between models and observations

in Journal of Geophysical Research (2012), 117(D5), 05303

N2 - The goal of this study is to determine how H2O and HDO measurements in water vapor can be used to detect and diagnose biases in the representation of processes controlling tropospheric humidity in ... [more ▼]

N2 - The goal of this study is to determine how H2O and HDO measurements in water vapor can be used to detect and diagnose biases in the representation of processes controlling tropospheric humidity in atmospheric general circulation models (GCMs). We analyze a large number of isotopic data sets (four satellite, sixteen ground-based remote-sensing, five surface in situ and three aircraft data sets) that are sensitive to different altitudes throughout the free troposphere. Despite significant differences between data sets, we identify some observed HDO/H2O characteristics that are robust across data sets and that can be used to evaluate models. We evaluate the isotopic GCM LMDZ, accounting for the effects of spatiotemporal sampling and instrument sensitivity. We find that LMDZ reproduces the spatial patterns in the lower and mid troposphere remarkably well. However, it underestimates the amplitude of seasonal variations in isotopic composition at all levels in the subtropics and in midlatitudes, and this bias is consistent across all data sets. LMDZ also underestimates the observed meridional isotopic gradient and the contrast between dry and convective tropical regions compared to satellite data sets. Comparison with six other isotope-enabled GCMs from the SWING2 project shows that biases exhibited by LMDZ are common to all models. The SWING2 GCMs show a very large spread in isotopic behavior that is not obviously related to that of humidity, suggesting water vapor isotopic measurements could be used to expose model shortcomings. In a companion paper, the isotopic differences between models are interpreted in terms of biases in the representation of processes controlling humidity. [less ▲]

Processes in regions of freshwater influence (ROFI)

in Journal of Marine Systems (1997), 12(1-4), 1-2

Processing and Characterization of Electrolytes Based on Doped Lanthanum Gallates for IT-SOFCs.

in Bossel, Ulf (Ed.) Sixth European Solid Oxide Fuel Cell Forum - Proceedings (2004, June)

Nowadays a huge interest exists towards the SOFC’s coming out on the large-scale market because of the variety of their advantageous applications. Clean conversion of chemical energy to electricity, co ... [more ▼]

Nowadays a huge interest exists towards the SOFC’s coming out on the large-scale market because of the variety of their advantageous applications. Clean conversion of chemical energy to electricity, co-generation of electricity and chemicals, low levels of noise and vibration, flexibility regarding the fuels used, high efhciency are evidences of this statement. One of the problems that still exist in this field concerns the effective and cost reasonable operation of SOFCs. In this context the lowering of the operation temperatures could be one of the solutions to this important issue. Because of their excellent oxide—ion conductivity and stability over a broad range of oxygen partial pressure, the appropriate doped lanthanum gallates are promising alternative electrolytes for intermediate temperature SOFCs (lT-SOFCs). The aim of this work is to present the experimental results, obtained in a close collaboration between the two Universities. The objects could be briefly outlined, as follows: to process planar electrolytes with different thicknesses, based on doped LaGaO3 via traditional ceramic techniques; to study the influence of the dopants type and their amount on the properties of electrolyte materials synthesized; to investigate the phase formation and phase composition in correlation with the phase diagrams, as well as the microstructure and elements distribution. A special emphasis was placed upon the electrochemical characterization in broad temperature range, using impedance spectroscopy. The results obtained have been discussed in details and conclusions have been drawn by common efforts of the two working groups. [less ▲]

Processing aortic and pulmonary artery waveforms to derive the ventricle time-varying elastance

in IFAC Proceedings Volumes (IFAC-PapersOnline) (2011), 18(PART 1), 587-592

Time-varying elastance of the ventricles is an important metric both clinically and as an input for a previously developed cardiovascular model. However, currently time-varying elastance is not normally ... [more ▼]

Time-varying elastance of the ventricles is an important metric both clinically and as an input for a previously developed cardiovascular model. However, currently time-varying elastance is not normally available in an Intensive Care Unit (ICU) setting, as it is an invasive and ethically challenging metric to measure. A previous paper developed a method to map less invasive metrics to the driver function, enabling an estimate to be achieved without invasive measurements. This method requires reliable and accurate processing of the aortic and pulmonary artery pressure waveforms to locate the specific points that are required to estimate the driver function. This paper details the method by which these waveforms are processed, using a data set of five pigs induced with pulmonary embolism, and five pigs induced with septic shock (with haemofiltration), adding up to 88 waveforms (for each of aortic and pulmonary artery pressure), and 616 points in total to locate. 98.2% of all points were located to within 1% of their true value, 0.81% were between 1% and 5%, 0.65% were between 5% and 10%, the remaining 0.32% were below 20%.© 2011 IFAC. [less ▲]

Processing GPS measurements during periods of high ionospheric activity

in Proceedings of EUREF 2002 Symposium (2003)

Processing of carbon fibers reinforced Mg matrix composites via pre-infiltration with Al

Conference (2011, September)

Mg matrix composites appear as suitable competitors to Al alloys for a wide number of applications, as they allow for a significant weight reduction while exhibiting potentially comparable mechanical ... [more ▼]

Mg matrix composites appear as suitable competitors to Al alloys for a wide number of applications, as they allow for a significant weight reduction while exhibiting potentially comparable mechanical properties. And a large variety of processing routes have already been considered for their production, including 'liquid state' processes such as squeeze casting. These techniques necessitate a very careful control of the wetting behaviour and of the possible interfacial reactions between the reinforcements and the molten metal, along with the solidification process. And this is more particularly true in the case of Mg matrix composites with carbon fibers reinforcements, as Mg alloys are known to exhibit a poor wetting behaviour on carbon substrates. [less ▲]

Processing of Ti alloys by additive manufacturing: a comparison of the microstructures obtained by laser cladding, selective laser melting and electron beam melting

in Materials Science Forum (2013)

Additive manufacturing processes such as laser cladding (LC) or selective laser melting (SLM) appear very promising in view of an economic near-net-shape production – and also, in the case of LC, the ... [more ▼]

Additive manufacturing processes such as laser cladding (LC) or selective laser melting (SLM) appear very promising in view of an economic near-net-shape production – and also, in the case of LC, the restoration - of complex and (almost) fully dense parts from Ti alloys. Both techniques involve the melting of a metallic powder with a laser. In the SLM process, the metallic powder is deposited layer by layer in a powder bed and then molten locally according to the desired shape, whereas in LC, the metallic powder is directly projected onto a substrate through a nozzle coaxial with the laser beam. The present research aims at comparing Ti-6Al-4V samples processed by these two techniques with reference samples produced by electron beam melting (EBM), another well established additive manufacturing process (patented by Arcam AB Company) in which a powder bed is molten locally by means of an electron beam. In all three processes, the melt pool undergoes an ultrafast cooling and solidifies very rapidly once the beam has left the area, thus giving rise to strongly out-of-equilibrium microstructures. Yet, each one of these processes also has its own specificities e.g. in terms of scanning strategy and of working atmosphere (low vacuum vs. protective Ar flow). In the present work, the microstructures obtained by these three processes have been compared in details, with a particular attention for characteristics such as porosity, grain size, and the various phases present. Since epitaxial growth of the newly deposited layer on the material previously solidified has been shown [1, 2] to exert a strong influence on the microstructure and on the resulting mechanical properties, great care has been taken to study the microstructural anisotropy associated with each one of the three processes. [less ▲]

Processing samples of benthic marine diatoms from Mediterranean oligotrophic areas

in Journal of Applied Phycology (2012), 24

The processing of benthic diatoms is tedious and involves several potentially damaging steps for cells. Although the preservation of siliceous frustules is of paramount importance in the implementation of ... [more ▼]

The processing of benthic diatoms is tedious and involves several potentially damaging steps for cells. Although the preservation of siliceous frustules is of paramount importance in the implementation of biotic indices, only few studies quantified treatment-induced cell losses. We assumed that commonly used treatments may lead to mechanical (centrifugation, sedimentation, boiling, sonication and mounting in Naphrax) and chemical (cold H2O2 digestion) damages on diatoms. We analysed the potential adverse effects of these treatments and the cleaning efficiency of H2O2 and incineration in order to find out the most suitable technique to process lightly silicified Mediterranean populations. Results showed that successive resuspensions of material after each concentration treatment (sedimentation and centrifugation) and low speed centrifugation did not alter the physical integrity of frustules. In contrast, boiling and sonication exhibited adverse effects especially on the preservation of large frustules and Naphrax mounting proved to be the most damaging step whatever the size of diatoms. For cleaning treatments, incineration provided the most satisfactory results and acted on a non-selective way as opposed to hydrogen peroxide which led to either a large number of non-cleaned frustules or dissolved valves. Our recommendations for processing samples of lightly silicified Mediterranean benthic diatoms include the use of low speed centrifugations, dehydration at room temperature, incineration and dry mounting. [less ▲]

La procession dansante d'Echternach

in Revue Générale : Religion, Politique, Histoire (1876), XXIV

Les processions de l’Europe baroque : définition, typologie et enjeux

Scientific conference (2009, March 27)