Dynamics of the Pionium with the Density Matrix Formalism

The evolution of pionium, the $\pi^+ \pi^-$ hydrogen-like atom, while passing through matter is solved within the density matrix formalism in the first Born approximation. We compare the influence on the pionium break-up probability between the standard probabilistic calculations and the more precise picture of the density matrix formalism accounting for interference effects. We focus our general result in the particular conditions of the DIRAC experiment at CERN.Comment: 14 pages, 2 figures, submitted to J. Phys. B: At. Mol. Phy

VALIDATION OF MOX CORE REACTIVITY VERSUS FLUX VARIATION.FEEDBACK ON DELAYED NEUTRON DATA

International audienc

Particle transport during asymmetric net-zero cyclic fluid flow: flow in tubes and radial flow in fractures

Cyclic fluid flow enhances transport in porous media. We study particle transport during asymmetric net-zero cyclic fluid flow where the fluid injection rate is higher than the withdrawal rate. Inside a tube, the threshold fluid velocity required to mobilize a particle depends on the relative particle size: larger particles obstruct flow more effectively than small particles and require a smaller velocity to be transported. Then, flow rates can be selected so particles move forward during the injection phase and remain stationary during withdrawal. Similarly, asymmetric cyclic fluid flow transports particles radially along fractures despite the net-zero fluid flow. The flow velocity decreases away from the injection point and particles migrate to a characteristic “terminal radial distance”. Unlike tube flow, a grain has a diminishing obstructing effect on the radial flow field, and the threshold flow rate required to mobilize grains increases with increasing particle size during radial flow

Antifungal and functional properties of starch-gellan films containing thyme (Thymus zygis) essential oil

[EN] Films based on starch-gellan blends at 9:1 and 8:2 ratios containing emulsified or lecithin encapsulated thyme (Thymus zygis) essential oil (EO) (0.25 or 0.5 g/g polymer), were obtained by casting method and characterized as to their structural, functional (mechanical, barrier and optical) and in vitro antifungal properties against Alternaria alternata (AA) and Botryotinia fuckeliana (BF). The EO retention during the film formation was also quantified. Lecithin encapsulation of the EO allowed for greater oil retention (45-55%), which enhanced the antifungal activity of the films, which were more effective against BF than AA. All films exhibited high oxygen barrier capacity, while lecithin improved the films water barrier properties and gloss, conferring them with a slightly brownish color. Lecithin also reduced the film stiffness and resistance to break and extensibility. Of the studied formulations, 8:2 S:G films with lecithin-encapsulated EO were very effective at controlling fungal growth, while exhibiting adequate functional properties as packaging/coating materials.The authors acknowledge the financial support for this study from the Ministerio de Economia y Competitividad (MINECO) of Spain, through the project AGL2016-76699-R. Mayra Sapper thanks the Conselleria de Educacion, Investigacion, Cultura y Deporte de la Comunitat Valenciana for the Santiago Grisolia grant GRISOLIA/2015/001.Sapper, MI.; Wilcaso, P.; Santamarina Siurana, MP.; Rosello Caselles, J.; Chiralt, A. (2018). Antifungal and functional properties of starch-gellan films containing thyme (Thymus zygis) essential oil. Food Control. 92:505-515. https://doi.org/10.1016/j.foodcont.2018.05.004S5055159

Direct calculation of the probability of pionium ionization in the target

We performed the first direct calculation of the probability of pionium (pi+pi- atom) ionization in the target. The dependence of the probability of pionium ionization in the target as a function of the pionium lifetime is established. These calculations are of interest of the DIRAC experiment at CERN, which aims to measure the pionium lifetime with high precision.Comment: 11 pages, 4 figures; submitted to "Physics of Atomic Nuclei" ("Yadernaya Fizika"

Antifungal starch-based edible films containing Aloe vera

[EN] Aloe vera gel, analysed as to its antifungal properties against six fungi causing plant diseases, was found to be most effective against Fusarium oxysporum. It was included in different ratios in starch based films plastiziced with glycerol to obtain antifungal films. These were characterized as to their physical (barrier and optical) and structural properties. Films containing the highest ratio of Aloe vera solids (1:1, with respect to starch) and different glycerol mass ratios with respect to starch (0.15 and 0.25) were analysed as to the water sorption and water plasticization effects, in order to discover the water sensitivity of the films in different RH ambients. Films with 0.15 g glycerol/g starch were more homogenous, with a lower degree of starch crystallization, reduced water vapour permeability and higher gloss and transparency. These films with the highest Aloe vera ratio were effective at controlling fungal decay and weight loss in cherry tomatoes. (C) 2017 Elsevier Ltd. All rights reserved.The authors acknowledge the financial support from the Spanish Ministerio de Economia y Competitividad throughout the project AGL2013-42989-R and AGL2016-76699-R. Rodrigo Ortega-Toro thanks Universidad Nacional Abierta y a Distancia from Colombia for their support through project PIE-01 2016. Authors also thank the Electron Microscopy Service of the Universitat Politecnica de Valencia for their technical assistance.Ortega-Toro, R.; Collazo-Bigliardi, S.; Rosello Caselles, J.; Santamarina Siurana, MP.; Chiralt, A. (2017). Antifungal starch-based edible films containing Aloe vera. Food Hydrocolloids. 72:1-10. https://doi.org/10.1016/j.foodhyd.2017.05.023S1107

Characterization and Engineering Properties of Dry and Ponded Class-F Fly Ash

Characterization studies conducted on Class-F fly-ash specimens gathered from different producers in the southeastern United States confirm general trends reported for fly ash worldwide. Additional tests and detailed analyses explain the spread in specific gravity (interparticle porosity cenospheres), highlight the tendency to segregation and layering, and show marked ferromagnetism. Furthermore, data show that early diagenetic cementation—within days after wetting—hinders densification and produces a fabric that is prone to collapse. New procedures are specifically developed to diagnose and characterize early diagenesis, including (1) pH measurements as an indicator of diagenetic potential, (2) test protocols to assess early diagenesis using oedometer tests and shear-wave velocity, and (3) procedures to determine realizable unit weights as reference values for the analyses of contractive or dilative tendencies and instability. In the absence of early diagenetic cementation, dilative fly-ash behavior is expected in the upper ≈20  m under monotonic shear loading. Flow instability may follow the failure of the containment structure if the ponded ash is saturated and has experienced hindered densification

Estimation of the hydraulic parameters of unsaturated samples by electrical resistivity tomography

In situ and laboratory experiments have shown that electrical resistivity tomography (ERT) is an effective tool to image transient phenomena in soils. However, its application in quantifying soil hydraulic parameters has been limited. In this study, experiments of water inflow in unsaturated soil samples were conducted in an oedometer equipped to perform three-dimensional electrical measurements. Reconstructions of the electrical conductivity at different times confirmed the usefulness of ERT for monitoring the evolution of water content. The tomographic reconstructions were subsequently used in conjunction with a finite-element simulation to infer the water retention curve and the unsaturated hydraulic conductivity. The parameters estimated with ERT agree satisfactorily with those determined using established techniques, hence the proposed approach shows good potential for relatively fast characterisations. Similar experiments could be carried out on site to study the hydraulic behaviour of the entire soil deposi