Inhibition of the formation and stability of inorganic colloids in the alkaline disturbed zone of a cementitious repository

The generation and stability of inorganic colloids have been studied under hyperalkaline conditions. For the generation of colloids, intact cores of Bromsgrove Sandstone were flushed with simulated cement leachates, and the eluates were ultrafiltered sequentially (12 μm, 1 μm, 0.1 μm and 30 kDa) for the separation of any colloids found. No colloid formation was observed during the experiments; however the analysis by ICP-MS of the eluates showed significant increases in Si and Al, indicating silicate mineral dissolution, as well as reduction of the concentration of Ca in the leachates indicating precipitation of secondary Ca-rich phases. Flow experiments with cement leachates spiked with tritiated water showed a noticeable reduction of the porosity of the sandstone as well as changes in the pore distribution. Additional stability experiments were carried out using model silica and Fe2O3 colloids. The experiments indicated that the stability of the colloids was mainly controlled by the concentration of Ca in solution and that both types were unstable under the chemical conditions in the alkaline disturbed zone. The presence of cement additives such as superplasticisers could enhance the stability of the colloids

Retention of chlorine-36 by a cementitious backfill

Radial diffusion experiments have been carried out to assess the migration of 36Cl, as chloride, through a cementitious backfill material. Further experiments in the presence of cellulose degradation products were performed to assess the effect of organic ligands on the extent and rate of chloride diffusion. Results show that breakthrough of 36Cl is dependent on chloride concentration: as the carrier concentration increases, both breakthrough time and the quantity retained by the cement matrix decreases. Experiments in the presence of cellulose degradation products also show a decrease in time to initial breakthrough. However, uptake at various carrier concentrations in the presence of organic ligands converges at 45% of the initial concentration as equilibrium is reached. The results are consistent with organic ligands blocking sites on the cement that would otherwise be available for chloride binding, though further work is required to confirm that this is the case. Post-experimental digital autoradiographs of the cement cylinders, and elemental mapping showed evidence of increased 36Cl activity associated with black ash-like particles in the matrix, believed to correspond to partially hydrated glassy calcium-silicate-sulfate-rich clinker

Aspects on anatomical parameters of the ovaries coypu (Myocastor coypus bonariensis) at sexual maturity

The aim of the present study was to determine anatomical parameters of ovaries of coypu in the\nsexual maturity throughout in situ and post extraction analysis. Thirty two virgin and sexually mature\nfemales aged between 6 and 9 months (mean 7 ± 0.84 months) and weighted 4.795 ± 399.6 gr\nwere used. Ovaries were degreased and weighed after their in situ identification with the anatomical\nrelations. The shape and the superficial aspect were registered and their cephalocaudal, dorsoventral\nand lateromedial diameters were recorded. Ovaries volume were determined considering their\ndiameters. Ovaries were located in the sublumbar area, showed ovoidal shape and creamy white\ncolour. The ovarian surface was lobed or with convolutions and protrusions. The average weight\nof the ovaries was 0.12 ± 0.04 g and the average volume was 561.99 ± 144.32 mm3\n. No statistical\ndifferences were detected between the right and left ovary of the same animal. The ovaries were\nsupported by the distal mesovarium. Each ovary was partially surrounded by the oviductal fimbriae\nand by an open or incomplete ovarian bursa which was limited by the distal mesovarium and the\nmesosalpinx. The ovarian bursa closed the cefhalic half of each ovary, showing a large communication\nwith the peritoneal cavity.Fil: Felipe A.E. Universidad del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Veterinarias. Área de Ciencias Morfológicas; ArgentinaFil: Fumuso E. Universidad del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Veterinarias. Fisiopatología de la Reproducción; ArgentinaFil: Fumuso E. Universidad del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Veterinarias. Centro de Investigación Veterinaria de Tandil; ArgentinaFil: Lombardo D. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias. Área de Histología y Embriología; ArgentinaEn este trabajo se determinaron los parámetros anatómicos de los ovarios del coipo en la madurez\nsexual mediante su análisis in situ y postextracción. Se trabajó con 36 hembras vírgenes y sexualmente\nmaduras, con edades comprendidas entre los 6 y los 9 meses (media de 7 ± 0.84 meses) y peso\nde 4.795 ± 399.6 gr. Se identificaron las relaciones anatómicas in-situ. Se registraron su forma y\naspecto superficial, se determinaron sus diámetros céfalo-caudal, dorso-ventral y látero-medial y\nse calculó su volumen. Los ovarios, de forma ovoidal y color cremoso blanquecino, se ubicaron\nen el área sublumbar. La superficie ovárica fue ligeramente lobulada o con protrusiones. El peso\nmedio de los ovarios fue de 0.12 ± 0.04 g y el volumen medio fue de 561.99 ± 144.32 mm3\n, no\nobservándose diferencias significativas en esas variables entre los ovarios derecho e izquierdo de un\nmismo animal. Los ovarios se observaron sostenidos por el mesovario distal y rodeados parcialmente\npor las fimbrias oviductales y una bolsa ovárica abierta o incompleta. La misma estuvo delimitada\npor el mesovario distal y el mesosalpinx y encerró la mitad cefálica de cada ovario, presentando una\namplia comunicación con la cavidad peritoneal

Development of a dairy fouling model to assess the efficacy of cleaning procedures using alkaline and enzymatic products

Dairy fouling is defined as the accumulation of thermally insulating materials or deposits from process fluids which are especially formed on heat transfer surfaces. The selection of suitable cleaning strategies to remove dairy fouling requires the understanding of its composition and the relationships with the surfaces where it is formed. For the industry, the development of novel strategies to test cleaning products, as well reducing water and energy consumption during the dairy processing operations is of enormous interest. The results showed the development of a laboratory-milk fouling model (MFM) with an average content of 52.8 mg/cm2 of fouling in the test coupons. Seven different cleaners were tested with a fouling removal effectiveness of between 55% and 97%. Additionally, for evaluating the cleaning process of the model, the turbidity of the cleaning solutions was assessed. We presented an enzymatic alternative to the use of traditional cleaning products, with a similar efficacy against the dairy fouling. 78% of fouling removal after the use of enzymatic solution, in comparison to the 72% of fouling removal after the use of alkaline cleaning products. A reduction in water (−33.3%) and temperature (−28.5%), as well as shorter cleaning times (−33%) than its chemical alternative, was observed.info:eu-repo/semantics/acceptedVersio

Neutrino Masses, Mixing and New Physics Effects

We introduce a parametrization of the effects of radiative corrections from new physics on the charged lepton and neutrino mass matrices, studying how several relevant quantities describing the pattern of neutrino masses and mixing are affected by these corrections. We find that the ratio omega = sin theta / tan theta_atm is remarkably stable, even when relatively large corrections are added to the original mass matrices. It is also found that if the lightest neutrino has a mass around 0.3 eV, the pattern of masses and mixings is considerably more stable under perturbations than for a lighter or heavier spectrum. We explore the consequences of perturbations on some flavor relations given in the literature. In addition, for a quasi-degenerate neutrino spectrum it is shown that: (i) starting from a bi-maximal mixing scenario, the corrections to the mass matrices keep tan theta_atm very close to unity while they can lower tan theta_sol to its measured value; (ii) beginning from a scenario with a vanishing Dirac phase, corrections can induce a Dirac phase large enough to yield CP violation observable in neutrino oscillations.Comment: 14 pages, 21 figures. Uses RevTeX4. Added several comments and references. Final version to appear in PR

Hybrid Stars in a Strong Magnetic Field

We study the effects of high magnetic fields on the particle population and equation of state of hybrid stars using an extended hadronic and quark SU(3) non-linear realization of the sigma model. In this model the degrees of freedom change naturally from hadrons to quarks as the density and/or temperature increases. The effects of high magnetic fields and anomalous magnetic moment are visible in the macroscopic properties of the star, such as mass, adiabatic index, moment of inertia, and cooling curves. Moreover, at the same time that the magnetic fields become high enough to modify those properties, they make the star anisotropic.Comment: Revised version with updated reference