5 research outputs found
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On the behaviour of nanoparticles in oil-in-water emulsions with different surfactants
The distribution of narrowly dispersed gold nanoparticles in hexane-in-water emulsions was studied for different surfactants. Good surfactants such as SDS and Triton X-100 block the oil-water interfaces and confine particles in the droplet. Other surfactants (Tween 85 and Span 20) form synergistic mixtures with the nanoparticles at the interfaces that lower the surface tension more than any component. Supraparticles with fully defined particle distribution form in the droplets only for surfactants that block the interface. Other surfactants promote the formation of fcc agglomerates. Nanoparticles in emulsions behave markedly different from microparticles-their structure formation is governed by free energy minimization, while microparticles are dominated by kinetics
Smoothing the tension with a dynamical dark energy model
The discrepancy between Planck data and direct measurements of the current
expansion rate and the matter fluctuation amplitude has become one
of the most intriguing puzzles in cosmology nowadays. The tension has
reached in the context of standard cosmology i.e CDM.
Therefore, explanations to this issue are mandatory to unveil its secrets.
Despite its success, CDM is unable to give a satisfying explanation to
the tension problem. Unless some systematic errors might be hidden in the
observable measurements, physics beyond the standard model of cosmology must be
advocated. In this perspective, we study a phantom dynamical dark energy model
as an alternative to CDM in order to explain the aforementioned
issues. This phantom model is characterised by one extra parameter,
, compared to CDM. We obtain a strong positive
correlation between and , for all data combinations. Using
Planck measurements together with BAO and Pantheon, we find that the and
the tensions are and , respectively. By introducing
a prior on the absolute magnitude, , of the SN Ia, the tension
decreases to with km s
Mpc and the tension reaches the value with .Comment: 11 pages, 4 figure
Composites en matiÚres premiÚres renouvelables et leurs procédés
National audienceThe development of new bio-based composites and efficient manufacturing methods that are suitable for series processing is the purpose of the current sub-project C4 of the Excellence Cluster MERGE, sponsored by DFG (Deutsche Forschungsgemeinschaft). Two different types of materials are combined: bio-based thermoplastic biopolymers such as bio-polyethylene (BioPE) or bio-polyamides (BioPA) and renewable reinforcing materials such as thin wood veneer or unidirectional flax fibers. To achieve a high-efficiency in terms of mass-production, reproducibility and flexibility, it is required to overlap several steps in the realization of semi-finished and final products. The improvement of the adhesion at the interface of the components, the implementation of continuous processes in order to increase energetically the yielding and the final design, through several methods, for the future potential applications are so many perspectives to achieve. MOTS-CLĂS : polymĂšre bio-basĂ© thermoplastique; renforcement naturel (Lin ou placage en bois) ; AmĂ©lioration de l'adhĂ©sion Ă l'interface matrice/renforcement ; ProcĂ©dĂ©s plastic/textile continu ; Application dans l'automobile et Ă©quipement sportifsLe dĂ©veloppement de matĂ©riaux bio-basĂ©s et de mĂ©thodes efficaces de mise en forme, adaptable Ă la production en sĂ©rie, est le but de l'actuel sous-projet C4 du programme d'excellence MERGE financĂ© par la DFG (Deutsche Forschungsgemeinschaft). Ainsi, deux types de matĂ©riaux sont combinĂ©s : Des polymĂšres bio-ressourcĂ©s thermoplastiques tels que bio-polyĂ©thylĂšne (BioPE) ou bio-polyamide (BioPA) et des matĂ©riaux de renforcements renouvelables tels que le placage en bois ou des fibres de lin unidirectionnelles continues. Pour atteindre un haut rendement en termes de production en masse, de reproductibilitĂ© et de flexibilitĂ©, il est requis de suivre plusieurs Ă©tapes dans la rĂ©alisation de produits semi-finis et finis. L'amĂ©lioration de l'adhĂ©sion Ă l'interface des composantes, la mise en place de procĂ©dĂ©s continus afin d'augmenter leur rendement, et la mise en forme finale, par diverses mĂ©thodes, pour des futures potentiels applications sont autant d'objectifs Ă atteindre
Comparative study between direct steam generation and molten salt solar tower plants in the climatic conditions of the eastern Moroccan region
International audienceThis study deals with a numerical investigation to assess and compare the thermal and economic performance of two solar tower power systems. It concerns the Molten Salt (MS) and Direct Steam Generation (DSG) technologies used as heat carrier and storage. For this purpose, a 50 MWe solar tower plant without thermal energy storage under the climatic conditions of the eastern Moroccan region is simulated with the System Advisor Model (SAM) software. The meteorological data has been collected via a high precision meteorological station located in Oujda city(34°40'53'' N 1°54'30.9'' W). The results are presented in terms of monthly energy production, annual energy output, and Levelized Electricity Cost (LEC). From these findings, it can be concluded that, for an amount annual Direct Normal Irradiance (DNI) of 1989.9 kWh/m2/yr, the molten salt plant has the highest annual energy production than the DSG (86.3 GWh for MS against 83.3 GWh for DSG) and the LEC of the Molten salt plant is 12.5 % lower than the DSG plant. ©2020. CBIORE-IJRED. All rights reserve