Search results for "upe"
showing 10 items of 7447 documents
CFD simulation of ZnO nanoparticle precipitation in a supercritical water synthesis reactor
2012
International audience; Continuous hydrothermal flow synthesis process has shown great advantages concerning the control of particle size and morphology through the optimization of supercritical water processing parameters. In particular, micromixing is a key issue of the process for controlling the nucleation mechanism. A Computational Fluid Dynamics (CFD) model is suggested for nanoparticle size determination using a population balance approach. Models for reaction kinetics, thermodynamics, nucleation and growth are presented. The effects of base concentration and hydrodynamics are investigated. Results show that the CFD may be valuable simulation tool for controlling the size and the sha…
Shaping of a ground state rotational wavepacket by frequency-chirped pulses
2001
0953-4075; A coherent rotational superposition state is produced in the ground vibronic level of N2 through the interaction of the molecule with the electric field vector of a nonresonant laser pulse. This rotational wavepacket is shaped with a linear frequency chirp of the laser field. The structural shape of the rotational coherences shows a strong dependence with the frequency-chirp amplitude. A comparison with a theoretical model allows the interpretation of the observed effects in terms of dephasing of the wavepacket induced by the laser phase distortion. Application of the presented results to the phase characterization of short XUV pulses is suggested.
Roflumilast N-oxide combined with PI3Kδ inhibitor improves the phenotype of early-onset COPD
2016
Background: Severe, early-onset COPD (Chronic Obstructive Pulmonary Disease) is characterized by a rapid decline in lung function at an early age with neutrophil over-activation. Roflumilast is approved as treatment for moderate and severe COPD at risk of exacerbation as add on therapy. Recent evidence indicates that the combination of PDE4 and PI3Kδ inhibitors show synergic anti-inflammatory properties. Objectives: To explore the effects from adding a selective PI3Kδ inhibitor to roflumilast N-oxide (RNO) in neutrophils isolated from peripheral blood of severe, early-onset COPD patients in in vitro models. Methods: Neutrophils were isolated from peripheral blood of 20 severe, early-onset C…
Nucleon localization function in rotating nuclei
2020
Background: An electron localization function was originally introduced to visualize bond structures in molecules. It became a useful tool to describe electron configurations in atoms, molecules and solids. In nuclear physics, a nucleon localization function (NLF) has been used to characterize clusters in light nuclei, fragment formation in fission and pasta phases in the inner crust of neutron stars. Purpose: We use the NLF to study the nuclear response to fast rotation. Methods: We generalize the NLF to the case of nuclear rotation. The extended expressions involve both time-even and time-odd local densities. Since current density and density gradient contribute to the NLF primarily at th…
From cacti to carnivores: Improved phylotranscriptomic sampling and hierarchical homology inference provide further insight into the evolution of Car…
2017
Premise of the study The Caryophyllales contain ~12,500 species and are known for their cosmopolitan distribution, convergence of trait evolution, and extreme adaptations. Some relationships within the Caryophyllales, like those of many large plant clades, remain unclear, and phylogenetic studies often recover alternative hypotheses. We explore the utility of broad and dense transcriptome sampling across the order for resolving evolutionary relationships in Caryophyllales. Methods We generated 84 transcriptomes and combined these with 224 publicly available transcriptomes to perform a phylogenomic analysis of Caryophyllales. To overcome the computational challenge of ortholog detection in s…
Early homogenous amorphous precursor stages of calcium carbonate and subsequent crystal growth in levitated droplets.
2008
An in situ study of the contact-free crystallization of calcium carbonate in acoustic levitated droplets is reported. The levitated droplet technique allows an in situ monitoring of the crystallization while avoiding any foreign phase boundaries that may influence the precipitation process by heterogeneous nucleation. The diffusion-controlled precipitation of CaCO3 at neutral pH starts in the initial step with the homogeneous formation of a stable, nanosized liquid-like amorphous calcium carbonate phase that undergoes in a subsequent step a solution-assisted transformation to calcite. Cryogenic scanning electron microscopy studies indicate that precipitation is not induced at the solution/a…
Escape of Supercritical-CO2 Fluids Trapped in Calcite Nano-metric Pores
2019
Flow of supercritical CO2-bearing fluids through a rock is a fundamental phenomenon which acts upon a great many geological processes ranging from seismic activity to formation of ore deposits. Atomic Force Microscopy scanning experiments allowed us to infer movement of supercritical CO2-bearing fluids through calcite crystals and relate it to natural decrepitation of nanoscale fluid inclusions. Calculated velocities exceed the rate of diffusion predicated via current vacancy models by several orders of magnitude implying that CO2-rich fluid movement through micro and nano-pore space may presently be greatly underestimated.
Quality and financial model in public universities
2001
Assuming that a unique model of university quality doesn’t exist, this article considers different models with their advantages and disadvantages. In this article we manifest the implications of each quality model with its sources of funding, paying special attention to the most recent reports from European, Spanish and Catalan universities about what would be the best funding for the university model they defend.
Solvation of a probe molecule by fluid supercooled water in a hydrogel at 200 K
2008
By combining electron paramagnetic resonance (EPR) measurements on a nitroxide probe and differential scanning calorimetry (DSC), we demonstrate existence of liquid supercooled water in a silica hydrogel with high hydration level down to temperatures of at least 198 K. Besides the major fraction of liquid supercooled water, a minor fraction crystallizes at about 236 K during cooling and melts at 246 K during heating. The liquid domains are of sufficient size to solvate the nearly spherical paramagnetic probe molecule TEMPO with a diameter of about 6 angstrom. Analysis of EPR spectra provides the rotational correlation time of the probe that is further used to compare the viscosity of the su…
Architetture rupestri a Caltabellotta
2020
Questo saggio descrivere i caratteri tipologici, le evoluzioni nel tempo e le connotazioni costruttive dell'architettura rupestre a Caltabellotta (AG). L’Italia rupestre, nella sua totalità, può – e non a torto - essere considerata un plusvalore se non ancora del tutto da scoprire, sicuramente da valorizzare e re-interpretare nel progetto di architettura e fruizione dei beni culturali e paesaggistici; non a caso, sovente le aree rupestri rappresentano un sistema attrattivo oggetto di tutela, inserito in piani paesistici e protetto da un vincolo di riserva naturale in ambito regionale, o ancora inserito in istituiti o istituendi distretti turistici. Il saggio ha analizzato cavità artificiali…