Estudio de laboratorio sobre utilización de zeolita natural versus zeolita sintética en la fabricación de mezclas semicalientes

Zeolite can be used as an ingredient in warm bituminous mixes to reduce manufacturing temperatures. The zeolite for this purpose is usually synthetic, but natural zeolite can also be used. The research presented in this paper analyzed the use of natural zeolite from Cuba in the form of sand and filler as an additive in warm asphalt mixes and compared it to asphalt mixes with synthetic zeolite. The mixes were given the Marshall tests, and their moisture sensitivity and stiffness modulus values were also obtained. The results showed that both types of mix had a similar performance, which was only slightly lower than that of the reference mix. The use of different dosages of natural zeolite in the mixes gave the best results when the zeolite was incorporated as filler. This study demonstrated that the use of natural zeolite is an effective way of reducing the temperature of bituminous mixes.Las mezclas semicalientes permiten una reducción de la temperatura de fabricación respecto a las mezclas tradicionales, mediante la modificación del proceso de producción en planta o el empleo de aditivos. En esta investigación se analiza el empleo de zeolita natural procedente de Cuba como aditivo para la fabricación de mezclas semicalientes, en comparación con el empleo de zeolitas artificiales. Para ello, a través de pruebas de estabilidad Marshall, sensibilidad al agua y módulos de rigidez se realiza un estudio comparativo. El resultado obtenido mostró un comportamiento similar entre las mezclas con zeolita natural y la sintética, resultando en ambos casos ligeramente inferior al obtenido por la mezcla patrón. Además, se evaluó la influencia de la adición de zeolita natural a la mezcla en diferentes porcentajes, como filler o como arena, obteniendo mejores resultados con la incorporación en la fracción filler

The Brightest Cluster Galaxy in Abell 85: The Largest Core Known so far

We have found that the brightest cluster galaxy (BCG) in Abell~85, Holm 15A, displays the largest core so far known. Its cusp radius, $r_{\gamma} = 4.57 \pm 0.06$ kpc ($4.26^{\prime\prime}\pm 0.06^{\prime\prime}$), is more than 18 times larger than the mean for BCGs, and $\geq1$ kpc larger than A2261-BCG, hitherto the largest-cored BCG (Postman, Lauer, Donahue, et al. 2012) Holm 15A hosts the luminous amorphous radio source 0039-095B and has the optical signature of a LINER. Scaling laws indicate that this core could host a supermassive black hole (SMBH) of mass $M_{\bullet}\thicksim (10^{9}-10^{11})\,M_{\odot}$. We suggest that cores this large represent a relatively short phase in the evolution of BCGs, whereas the masses of their associated SBMH might be set by initial conditions.Comment: 14 pages, 3 figure, 2 tables, accepted for publication in ApJ Letters on October 6th, 2014, replacement of previous manuscript submitted on May 30th, 2014 to astro-p

Does BIC Estimate and Forecast Better than AIC?

We test two questions: (i) Is the Bayesian Information Criterion (BIC) more parsimonious than Akaike Information Criterion (AIC)?, and (ii) Is BIC better than AIC for forecasting purposes? By using simulated data, we provide statistical inference of both hypotheses individually and then jointly with a multiple hypotheses testing procedure to control better for type-I error. Both testing procedures deliver the same result: The BIC shows an in- and out-of-sample superiority over AIC only in a long-sample context

A note about the ground state of the H3+{\rm H}_3^+ hydrogen molecular ion

Three simple $7-, (7+3)-, 10-$parametric trial functions for the ${\rm H}_3^+$ molecular ion are presented. Each of them provides subsequently the most accurate approximation for the Born-Oppenheimer ground state energy among several-parametric trial functions. These trial functions are chosen following a criterion of physical adequacy and includes the electronic correlation in the exponential form $\sim\exp{(\gamma r_{12})}$, where $\gamma$ is a variational parameter. The Born-Oppenheimer energy is found to be $E=-1.340 34, -1.340 73, -1.341 59$\,a.u., respectively, for optimal equilateral triangular configuration of protons with the equilibrium interproton distance $R=1.65$\,a.u. The variational energy agrees in three significant digits (s.d.) with most accurate results available at present as well as for major expectation values.Comment: 12 pages, 1 figure, 3 table

Does BIC Estimate and Forecast Better than AIC?

We test two questions: (i) Is the Bayesian Information Criterion (BIC) more parsimonious than Akaike Information Criterion (AIC)?, and (ii) Is BIC better than AIC for forecasting purposes? By using simulated data, we provide statistical inference of both hypotheses individually and then jointly with a multiple hypotheses testing procedure to control better for type-I error. Both testing procedures deliver the same result: The BIC shows an in- and out-of-sample superiority over AIC only in a long-sample context

The hydrogen molecule H2\rm{H}_{2} in inclined configuration in a weak magnetic field

Highly accurate variational calculations, based on a few-parameter, physically adequate trial function, are carried out for the hydrogen molecule \hh in inclined configuration, where the molecular axis forms an angle $\theta$ with respect to the direction of a uniform constant magnetic field ${\bf B}$, for $B=0,\, 0.1,\, 0.175$ and $0.2\,$a.u. Three inclinations $\theta=0^\circ,\,45^\circ,\,90^\circ$ are studied in detail with emphasis to the ground state $1_g$. Diamagnetic and paramagnetic susceptibilities are calculated (for $\theta=45^\circ$ for the first time), they are in agreement with the experimental data and with other calculations. For $B=0,\, 0.1$ and $0.2\,$a.u. potential energy curves $E$ vs $R$ are built for each inclination, they are interpolated by simple, two-point Pad\'e approximant $Pade[2/6](R)$ with accuracy of not less than 4 significant digits. Spectra of rovibrational states are calculated for the first time. It was found that the optimal configuration of the ground state for $B \leq B_{cr}=0.178\,$a.u. corresponds always to the parallel configuration, $\theta=0$, thus, it is a $^1\Sigma_g$ state. The state $1_g$ remains bound for any magnetic field, becoming metastable for $B > B_{cr}$, while for $B_{cr} < B < 12$\,a.u. the ground state corresponds to two isolated hydrogen atoms with parallel spins.Comment: 31 pages, 11 Tables, 7 Figures (2 new), following referee's suggestions parts 4,5,6 essentially rewritten, to be published at Journal of Quantitative Spectroscopy and Radiative Transfe

Closed-shell to split-shell stability of isovalent clusters

Metallic clusters containing 2, 8, 18, and 20 electrons are now known to exhibit enhanced stability that can be reconciled because of filled 1S, 1P, 1D, and 2S electronic shells within a simplified confined nearly free electron (NFE) gas. Here, we present first-principles studies on three isovalent clusters, i.e., ZnMg8, CuMg8−, and AuMg8−, each with 18 valence electrons. All the clusters exhibit local energetic stability but with differing origins. Although the stability of ZnMg8 can be reconciled within the conventional confined NFE picture with filled 1S2, 1P6, and 1D10shells, CuMg8− and AuMg8− are shown to be stable despite the unfilled D-shell. Their stability can be understood as a crystal field–like splitting of the otherwise degenerate D-shell because of internal electric fields of the positive ion cores that lead to a filled 1S2, 1P6, 1D8, 2S2 sequence separated by unfilled D2 states that form a large gap. We also examine the progression toward the metallic character in ZnMgn clusters, because isolated Mg and Zn atoms have filled valence 4s2 and 3s2 atomic states. As Mg atoms are added to a Zn atom, the excited atomic p-states in the Mg atoms hybridize rapidly with Zn and Mg s-states to promote a metallic character that evolves more rapidly than in pure Mgn clusters

Effect of disodium/calcium malate or Saccharomyces cerevisiae supplementation on growth performance, carcass quality, ruminal fermentation products, and bood metabolites of heifers

The aim of this study was to assess the effects of malate salts and Saccharomyces cerevisiae culture on growth performance, carcass quality, ruminal fermentation products, and blood metabolites in heifers raised under southern Europe practical farm conditions. A total of 108 Charolaise cross heifers (214 ± 27.3 kg BW and 6.4 ± 1.1 mo of age) were housed in 18 pens of 6 animals each and used in a 114-d feedlot study. There was a totally randomized experimental design, and 6 pens were assigned to each of the following experimental diets: a control (no supplementation), the control plus 4 g of disodium/calcium malate mixture per kilogram of concentrate (2.12 g malate/kg), and the control plus 0.15 g of S. cerevisiae CBS 493.94 per kilogram of concentrate (1.5 × 108 cfu/kg). The control diet consisted of wheat–barley–based pelleted concentrate (32% starch, DM basis) and full-length barley straw. Concentrate and straw were fed separately ad libitum (5% orts) in an 88:12 ratio. On Days 0, 56, and 114, ruminal fluid and blood samples were obtained from each heifer between 2 and 2.5 h after the morning feeding by ruminocentesis and tail venipuncture, respectively. Body weight, concentrate ADFI, and G:F were recorded at 28, 56, 84, and 114 d. At slaughter, hot carcass weight and yield and carcass classification were determined in 2 representative heifers per pen (12 animals per dietary treatment). Supplementation with malate salts or S. cerevisiae did not affect concentrate ADFI (P = 0.98), ADG (P = 0.74), or G:F (P = 0.50) at any time during the experiment. At slaughter, there were no differences in carcass weight (P = 0.86), classification (P = 0.18), or carcass yield (P = 0.84) among experimental groups. Also, there were no differences treatments on ruminal pH (P = 0.24), ruminal fermentation products (P = 0.69, P = 0.88, and P = 0.93 for total VFA, NH3–N, and lactate, respectively), and blood metabolites (P = 0.96, P = 0.82, and P = 0.15 for glucose, urea N, and lactate, respectively). In conclusion, under the feeding and management conditions of this study, diet supplementation with malate salts or S. cerevisiae did not have any significant effects on growth performance, carcass quality, ruminal fermentation products, and blood metabolites

SDSS IV MaNGA: Dependence of Global and Spatially Resolved SFR-M ∗ Relations on Galaxy Properties

Indexación: Scopus.The galaxy integrated Hα star formation rate-stellar mass relation, or SFR(global)-M ∗(global) relation, is crucial for understanding star formation history and evolution of galaxies. However, many studies have dealt with SFR using unresolved measurements, which makes it difficult to separate out the contamination from other ionizing sources, such as active galactic nuclei and evolved stars. Using the integral field spectroscopic observations from SDSS-IV MaNGA, we spatially disentangle the contribution from different Hα powering sources for ∼1000 galaxies. We find that, when including regions dominated by all ionizing sources in galaxies, the spatially resolved relation between Hα surface density (ΣHα(all)) and stellar mass surface density (Σ∗(all)) progressively turns over at the high Σ∗(all) end for increasing M ∗(global) and/or bulge dominance (bulge-to-total light ratio, B/T). This in turn leads to the flattening of the integrated Hα(global)-M ∗(global) relation in the literature. By contrast, there is no noticeable flattening in both integrated Hα(H ii)-M ∗(H ii) and spatially resolved ΣHα(H ii)-Σ∗(H ii) relations when only regions where star formation dominates the ionization are considered. In other words, the flattening can be attributed to the increasing regions powered by non-star-formation sources, which generally have lower ionizing ability than star formation. An analysis of the fractional contribution of non-star-formation sources to total Hα luminosity of a galaxy suggests a decreasing role of star formation as an ionizing source toward high-mass, high-B/T galaxies and bulge regions. This result indicates that the appearance of the galaxy integrated SFR-M ∗ relation critically depends on their global properties (M ∗(global) and B/T) and relative abundances of various ionizing sources within the galaxies.http://iopscience.iop.org/article/10.3847/1538-4357/aaa9bc/met