Artificial weathering pools of calcium-rich industrial waste for CO2 sequestration

Processes of carbonation of calcium-rich aqueous industrial wastes from acetylene production were performed mimicking rock weathering, using the atmospheric carbon dioxide as reactant. This residue was carbonated exposing it to the air in artificial pools with controlled solid-to-liquid and surface-to-volume ratios, and the efficiency of this simple mineral carbonation process was maximized. Considering realistic values of just one acetylene production plant, the intelligent handling of the calcium-rich waste would make it possible to counteract the emission of around 800t of carbon dioxide per year, so the CO2 emissions of the acetylene production could be completely compensated and its carbon footprint significantly reduced.X-ray diffraction patterns and thermogravimetric analyses reported the conversion, up to 88%, of the calcium hydroxide into calcium carbonate under atmospheric conditions. So, considering a realistic industrial scale-up, 476kg of CO2 could be captured with 1t of dry waste. The morphology of the grains is resolved by electron microscopy, and can be described as needles 15nm wide and 200nm long arranged in grains smaller than 1 micron. We exploit these nanometric textural parameters (nanometric pores and particles having a specific surface area ∼50m2/g) to design an efficient carbon fixation procedure. The aim of this work is to propose this simple carbonation technology, based on aqueous alkaline industrial waste, as a contribution to reducing global CO2 emissions.Junta de Andalucía TEP115Ministerio de Ciencia e Innovación PIA42008-3

A New Form of Path Integral for the Coherent States Representation and its Semiclassical Limit

The overcompleteness of the coherent states basis leads to a multiplicity of representations of Feynman's path integral. These different representations, although equivalent quantum mechanically, lead to different semiclassical limits. Two such semiclassical formulas were derived in \cite{Bar01} for the two corresponding path integral forms suggested by Klauder and Skagerstan in \cite{Klau85}. Each of these formulas involve trajectories governed by a different classical representation of the Hamiltonian operator: the P representation in one case and the Q representation in other. In this paper we construct a third representation of the path integral whose semiclassical limit involves directly the Weyl representation of the Hamiltonian operator, i.e., the classical Hamiltonian itself.Comment: 16 pages, no figure

Enlightening the atomistic mechanisms driving self-diffusion of amorphous Si during annealing

We have analyzed the atomic rearrangements underlying self-diffusion in amorphous Si during annealing using tight-binding molecular dynamics simulations. Two types of amorphous samples with different structural features were used to analyze the influence of coordination defects. We have identified several types of atomic rearrangement mechanisms, and we have obtained an effective migration energy of around 1 eV. We found similar migration energies for both types of samples, but higher diffusivities in the one with a higher initial percentage of coordination defects.Comment: 9 pages, 4 figure

Tourism in Azores Islands: Persistence in the Monthly Arrivals

This study analyses the persistence in the international monthly arrivals to the Azores Islands using a model based on fractional integration and seasonal autoregressions. The estimated fractional differencing parameter gives an indication of the long run evolution of the series. We use both aggregate data and disaggregate monthly data by location of origin and island destination. The results show that the aggregate series corresponding to the total number of arrivals is a nonstationary I(d) process with d above 1, and the most persistent ones are those travelling to Säo Miguel, especially from Holland, Finland, Norway, Germany, Denmark and the UK.Monthly arrivals; Seasonal fractional integration; Persistence; Azores Islands.

Radion stabilization from the vacuum on flat extra dimensions

Volume stabilization in models with flat extra dimension could follow from vacuum energy residing in the bulk when translational invariance is spontaneously broken. We study a simple toy model that exemplifies this mechanism which considers a massive scalar field with non trivial boundary conditions at the end points of the compact space, and includes contributions from brane and bulk cosmological constants. We perform our analysis in the conformal frame where the radion field, associated with volume variations, is defined, and present a general strategy for building stabilization potentials out of those ingredients. We also provide working examples for the interval and the $T^n/Z_2$ orbifold configuration.Comment: Comments and clarifications added throughout the text. Typos corrected and references added. Final version, 27 pages, five figures include

Ruthenium Catalyzed Oxidative Cleavage of High Oleic Sunflower Oil: Considerations Regarding the Synthesis of a Fully Biobased Triacid

Tricarboxylic acids are molecules of interest for the synthesis of highly cross-linked polymers, for instance, for the curing of epoxy resins. Herein, a synthesis route to a novel high oleic sunflower oil based triacid is described by applying a ruthenium catalyzed oxidative cleavage of its double bonds. A statistical concept is devised for the prediction of the yields of mono-, di-, and trifunctional derivatives that can be formed from high oleic sunflower oil, depending on the overall conversion of double bonds into this functional group and the overall oleic acid content of the used oil. This concept proved to be highly useful for the explanation of seemingly moderate triacid yields, which are inherently dependent on the unsaturated fatty acid content of the used oil. All obtained sunflower oil based polyacids are fully analyzed by attenuated total reflection infrared spectroscopy (ATR-IR), electrospray ionization mass spectrometry (ESI-MS), $^1$H, $^{13}$C, and quantitative $^{31}$P nuclear magnetic resonance (NMR) spectroscopy. In addition, a more sustainable purification procedure is developed to obtain a polymerizable mixture of polyacids containing more than 2.0 carboxylic acids per molecule in average. Practical applications: Tricarboxylic acids are valuable monomers for the synthesis of cross-linked polymers. The herein reported procedure represents a hitherto unknown synthesis route towards a new triacid and polyacid mixture directly from high oleic sunflower oil

Non-equilibrium dynamics of dipolar polarons

We study the out-of-equilibrium quantum dynamics of dipolar polarons, i.e., impurities immersed in a dipolar Bose-Einstein condensate, after a quench of the impurity-boson interaction. We show that the dipolar nature of the condensate and of the impurity results in anisotropic relaxation dynamics, in particular, anisotropic dressing of the polaron. More relevantly for cold-atom setups, quench dynamics is strongly affected by the interplay between dipolar anisotropy and trap geometry. Our findings pave the way for simulating impurities in anisotropic media utilizing experiments with dipolar mixtures.Comment: 23 pages, 6 figures

Atazanavir-Based Therapy Is Associated with Higher Hepatitis C Viral Load in HIV Type 1-Infected Subjects with Untreated Hepatitis C

Comunicación cortaWe assessed the relationship between atazanavir (ATV)-based antiretroviral treatment (ART) and plasma hepatitis C virus (HCV) viral load in a population of HIV/HCV-coinfected patients. HIV/HCV-coinfected patients who received ART based on a protease inhibitor (PI) or nonnucleoside reverse transcriptase inhibitor (NNRTI) were included. Patients were stratified by ART drug [ATV/rtv, lopinavir (LPV/rtv), efavirenz (EFV), nevirapine (NVP), and other PIs], HCV genotype (1/4 and 2/3), and IL28B genotype (CC and non-CC). The Kruskal-Wallis test and chi-squared test were used to compare continuous and categorical variables, respectively. Multivariate analysis consisted of a stepwise linear regression analysis. Six hundred and forty-nine HIV/HCV-coinfected patients were included. HCV genotype 1/4 patients who received ATV had higher HCV RNA levels [6.57 (5.9-6.8) log IU/ml] than those who received LPV [6.1 (5.5-6.5) log IU/ml], EFV [6.1 (5.6-6.4) log IU/ml], NVP [5.8 (5.5-5.9) log IU/ml], or other PIs [6.1 (5.7-6.4) log IU/ml] (p=0.014). This association held for the IL28B genotype (CC versus non-CC). The association was not found in patients carrying HCV genotypes 2/3. The linear regression model identified the IL28B genotype and ATV use as independent factors associated with HCV RNA levels. ATV-based therapy may be associated with a higher HCV RNA viral load in HIV/HCV-coinfected patients

Alternating-domain supersolids in binary dipolar condensates

Two-component dipolar condensates are now experimentally producible, and we theoretically investigate the nature of supersolidity in this system. We predict the existence of a binary supersolid state in which the two components form a series of alternating domains, producing an immiscible double supersolid. Remarkably, we find that a dipolar component can even induce supersolidity in a nondipolar component. In stark contrast to single-component dipolar supersolids, alternating-domain supersolids do not require quantum stabilization, and the number of crystal sites is not strictly limited by the condensate populations, with the density hence being substantially lower. Our results are applicable to a wide range of dipole moment combinations, marking an important step towards long-lived bulk-supersolidity