Geometric approach to non-relativistic Quantum Dynamics of mixed states

In this paper we propose a geometrization of the non-relativistic quantum mechanics for mixed states. Our geometric approach makes use of the Uhlmann's principal fibre bundle to describe the space of mixed states and as a novelty tool, to define a dynamic-dependent metric tensor on the principal manifold, such that the projection of the geodesic flow to the base manifold gives the temporal evolution predicted by the von Neumann equation. Using that approach we can describe every conserved quantum observable as a Killing vector field, and provide a geometric proof for the Poincare quantum recurrence in a physical system with finite energy levels.Comment: 19 pages, 1 figure. Minor corrections. Accepted to Journal of Mathematical Physic

Geochemical characterisation and modelling of the Luchon hydrothermal system (Central Pyrenees, France) and lessons learnt for the use of geochemical modelling techniques in granite-hosted alkaline thermal waters

Alkaline hydrothermal systems hosted in granitic rocks have been extensively investigated as natural analogues for radioactive waste disposal and for the geological storage of CO2. Thereby, their geochemical characterisation provides useful information for the long-term performance assessment predictions. The geochemical modelling of one of these alkaline hydrothermal systems has been performed in Luchon (France), together with the application of different geothermometrical techniques to determine the temperature, pH and mineral equilibrium conditions at depth. The modelling results show that the main processes controlling the hydrogeochemical evolution of this system are: (1) the mixing between deep thermal and cold surface waters, (2) the conductive cooling and (3) the external input of CO2. Other important results are that the most alkaline thermal waters are characterised by a high pH-buffering capacity during the mixing processes, and that the high pH values that characterise these thermal waters are not only inherited from the deep reservoir but strongly enhanced by conductive cooling. The reservoir temperature predicted by the geothermometrical modelling is in the range of 117 ± 8 °C, in good agreement with the temperatures ranging from 108 to 133 °C predicted by the classical geothermometers. The results of these calculations indicate as well that the thermal solutions have reached equilibrium with quartz, albite, potassium feldspar, zoisite and prehnite, and that a re-equilibirum with kaolinite and calcite is reached during their ascent to the surface. Another important outcome is that the precipitation of calcite in the deep reservoir could take place as a CO2 mineral trapping mechanism in similar systems. Further, the sharp influence of the surface waters on the deep thermal waters reveals a high susceptibility of the system to potential contamination processes

Trans-amidate platinum complexes anchoring water and N-donor molecules. The importance of hydrogen bonding

The square planar bisnitrile platinum(II) derivatives PtCl2(NCR)2 (R=Ph (1 a); Et (1 b); p-C6H4F (1 c); p-C6H4tBu (1 d); m-C6H3Me2 (1 e); o, p-C6H2Me3 (1 f)) react with tetrabutylammonium hydroxide to render the monoaquo NBu4]trans-PtCl(HNCOR)2(OH2)] (2 a–2 f). The water molecule is s-coordinated to platinum and the binding is reinforced by two strong hydrogen bonds to the neighboring amidate ligands (OH···OC). Substitution of water in 2 a by N-donor ligands can be efficiently achieved only in the presence of a dehydrating agent as magnesium sulphate or 4 Å molecular sieves. By following this strategy, compounds NBu4]trans-PtCl(HNCOPh)2(NH2R’)] (R’=H (3), NH2 (4), tBu (5 a), p-C6H4Me (5 b) have been isolated. The incoming ligands are s-coordinated to platinum and also establish strong hydrogen bonds to the amidates (NH···OC). Treatment of 2 a with halogens causes oxidation at the metal center, rendering the platinum(IV) derivatives NBu4]PtClX2(HNCOPh)2(OH2)] (X=Cl (6 a), Br (6 b), I (6 c))

Enhancing resonant circular-section haloscopes for dark matter axion detection: approaches and limitations in volume expansion

Haloscopes, microwave resonant cavities utilized in detecting dark matter axions within powerful static magnetic fields, are pivotal in modern astrophysical research. This paper delves into the realm of cylindrical geometries, investigating techniques to augment volume and enhance compatibility with dipole or solenoid magnets. The study explores volume constraints in two categories of haloscope designs: those reliant on single cavities and those employing multicavities. In both categories, strategies to increase the expanse of elongated structures are elucidated. For multicavities, the optimization of space within magnets is explored through 1D configurations. Three subcavity stacking approaches are investigated, while the foray into 2D and 3D geometries lays the groundwork for future topological developments. The results underscore the efficacy of these methods, revealing substantial room for progress in cylindrical haloscope design. Notably, an elongated single cavity design attains a three-order magnitude increase in volume compared to a WC-109 standard waveguide-based single cavity. Diverse prototypes featuring single cavities, 1D, 2D, and 3D multicavities highlight the feasibility of leveraging these geometries to magnify the volume of tangible haloscope implementations

Modulating the bitterness of Empeltre olive oil by partitioning polyphenols between oil and water phases: Effect on quality and shelf life

Bitterness is a positive sensorial attribute of olive oil that mainly depends on phenol concentration. However, excessive bitterness may be unpleasant for consumers. The aim of this investigation was to evaluate if partitioning polyphenols between oil and water phases could modulate the bitterness of an Empeltre olive oil containing a phenolic concentration higher than the typical content for this olive oil variety. The linear relationship observed between the percentage of oil in the extraction system and the percentage of phenols removed from the oil permitted estimating the olive oil-to-water ratio required to reduce the concentration of phenols for a given value in order to modulate Empeltre olive oil bitterness. Olive oils after liquid–liquid extraction did not develop any negative sensory attributes, and their physicochemical parameters were not substantially affected. Liquid–liquid extraction using water as a solvent is a procedure capable of effectively reducing the total phenol compounds of Empeltre extra virgin olive oil and, as a consequence, of reducing its bitterness intensity without affecting the highest commercial category determined by the parameters legally established by European Community regulations just after extraction and during nine months of storage

The effect of sepiolite on the compatibilization of polyethylene thermoplastic starch blends for environmentally friendly films

The final publication is available at Springer via http://dx.doi.org/10.1007/s10853-014-8647-8[EN] Green polyethylene is a new and attracting polymer from biobased resources (sugarcane) and identical properties to petroleum-based polyethylene. Its potential in the packaging industry is really promising. In this work, we report the use of different compatibilizer systems for green polyethylene (from sugarcane) and thermoplastic starch (30 wt% TPS) in order to increase ductile mechanical properties and biodegradable content. Typical petroleum-based graft copolymer of polyethylene with maleic anhydride (PE-g-MA) is used as reference compatibilizer, and new compatibilizer systems are developed using sepiolite. The obtained results show that sepiolite-based compatibilizers provide good compatibilization properties as observed by a remarkable increase in elongation at break and a noticeable size reduction of the TPS domains dispersed in the green polyethylene matrix as observed by scanning electron microscopy (SEM).This study has been funded by the ‘‘Conselleria d’Educacio´, Cultura i Esport’’—Generalitat Valenciana (Reference number: GV/2014/008). Authors thank Tolsa S.A for kindly supply sepiolite for this study and Microscopy Services at UPV for helping in using SEM and TEM techniques.Samper Madrigal, MD.; Fenollar Gimeno, OÁ.; Dominici, F.; Balart Gimeno, RA.; Kenny, JM. (2015). The effect of sepiolite on the compatibilization of polyethylene thermoplastic starch blends for environmentally friendly films. 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Synthesis, Photochemical, and Redox Properties of Gold(I) and Gold(III) Pincer Complexes Incorporating a 2,2′:6′,2″-Terpyridine Ligand Framework

Reaction of [Au(C6F5)(tht)] (tht = tetrahydrothiophene) with 2,2′:6′,2″-terpyridine (terpy) leads to complex [Au(C6F5)(η1-terpy)] (1). The chemical oxidation of complex (1) with 2 equiv of [N(C6H4Br-4)3](PF6) or using electrosynthetic techniques affords the Au(III) complex [Au(C6F5)(η3-terpy)](PF6)2 (2). The X-ray diffraction study of complex 2 reveals that the terpyridine acts as tridentate chelate ligand, which leads to a slightly distorted square-planar geometry. Complex 1 displays fluorescence in the solid state at 77 K due to a metal (gold) to ligand (terpy) charge transfer transition, whereas complex 2 displays fluorescence in acetonitrile due to excimer or exciplex formation. Time-dependent density functional theory calculations match the experimental absorption spectra of the synthesized complexes. In order to further probe the frontier orbitals of both complexes and study their redox behavior, each compound was separately characterized using cyclic voltammetry. The bulk electrolysis of a solution of complex 1 was analyzed by spectroscopic methods confirming the electrochemical synthesis of complex 2

Influence of SO2 on CO2 storage for CCS technology: Evaluation of CO2/SO2 co-capture

In this work, we determined the influence of SO2 as an impurity in anthropogenic CO2 on carbon capture and storage (CCS) technology. We evaluated the impact on selected injection and storage parameters and the Joule-Thomson coefficient to assess the safety of long-term geological storage of CO2. For this purpose, we obtained new pressure-density-temperature-composition, vapor-liquid-equilibrium, and pressure-speed of sound-temperature-composition experimental data for CO2-rich mixtures containing SO2. To increase the general understanding of the impact of SO2, the compositions cover possible co-capture mixtures, SO2-enriched mixtures, and mixtures similar to industrial emissions. Temperatures and pressures were based on relevant geological storage site values. Our experimental results were used to validate the EOS-CG and PC-SAFT equations of state (EoSs) for CO2 + SO2 under the studied CCS conditions. On the understanding that the chemical reactivity effects due to SO2 have not been considered, we concluded that the presence of SO2 is profitable in most of the studied aspects, especially in the case of shallow reservoirs, and that CO2/SO2 co-capture may be considered as an alternative approach to reduce the costs of CO2 purification. Based on the assessment of the impact of 5 mol% SO2 in the injected fluid in seven saline aquifers, we determined that the reservoirs that would receive the most benefit were Sleipner, Nagaoka and Frio

Ferrocenyl gold complexes as efficient catalysts

More than half a century after the discovery of the ferrocene structure in 1951, it remains as a suitable building block in many research areas, including catalysis with the development of key chiral catalysts. On the other hand, gold-mediated catalysis has been raised in recent years, allowing the creation of a great variety of C-C bonds and C-heteroatom bonds. In this context, this review covers the recent advances made with the combination of these two iconic figures in the organometallic chemistry field, since the first gold catalyzed reaction using a ferrocene ligand reported in 1986. The combination of the excellent properties and versatility of this metallocene, has allowed the obtainment of a plethora of ligands for metal catalysis, although their use joined to gold catalysis is still scarcely explored

Modelización cinética de la interacción agua-roca

A review of basic concepts in kinetics of low temperature natural systems is given: elementary and overall reactions, steady state and reaction mechanism, sequential reactions, parallel reactions and rate-determining step, temperature dependence of rate constant and principle of detailed balancing. The current status of kinetics modeling of water/rock interaction is treated. The comparison of the mean life of the processes with the residence time of the water in the system is very useful to decide the application or not of the kinetics treatment to the water/rock interaction processes. The right application of the kinetics treatment to the water/rock interaction needs the knowledge of the magnitude of the surface through which the water/rock reaction take place and its variation with time. Two ways to treat kinetically the water/rock interaction are the Mass Transfer method and the quasi-stationary state method.En este artículo se hace una descripción de los conceptos básicos utilizados en el tratamiento cinético de sistemas naturales de baja temperatura: reacciones elementales y completas, estado estacionario y mecanismo de reacción, reacciones secuenciales y paralelas, dependencia de la temperatura en la tasa de reacción y relaciones entre termodinámica y cinética. Asimismo se expone el estado del arte actual de la modelización cinética de la interacción agua/roca. Para decidir la aplicación o no del tratamiento cinético en la interacción agua/roca, es importante el estudio de la relación entre las vidas medias de los procesos y el tiempo de residencia del agua en el sistema. El éxito de la aplicación del tratamiento cinético a la interacción agua/roca pasa por el conocimiento de la superficie a través de la cual se verifican las reacciones agua/roca y su variación con el tiempo. Dos formas de aplicar el tratamiento cinético a los procesos de interacción agua/roca son el método de la transferencia de masa y el del estado cuasi-estacionario