Synthesis, crystal structure and spectroscopic characterization of a new organic bismuthate (III) [C9H28N4][Bi2Cl10].H2O

The chemical preparation, crystal structure and spectroscopic characterization of [C9H28N4][Bi2Cl10].H2O have been reported. This compound crystallizes in the monoclinic system in space group P21/c and cell parameters a = 12.2385 (6), b = 17.3062 (7), c = 13.0772 (6) Å, β = 104.475 (5)°, Z = 4 and V = 2681.9 (2) Å3. Its crystal structure has been determined and refined to R = 0.049, using 5848 independent reflections. The atomic arrangement can be described by an alternation of organic and inorganic layers. The inorganic layer built up of [Bi2Cl10]4– bioctahedra arranged in sandwich between the organic layer. The organic groups are interconnected by the water molecules through N-H…O(W) hydrogen bonds to form infinite zig-zag chains spreading along the b-axis. These Chains are themselves interconnected by means of the N–H…Cl hydrogen bonds originating from [Bi2Cl10]4– anions, to form a three-dimensional network. Intermolecular Cl…Cl interactions between adjacent dimeric [Bi2Cl10]4– anions have been observed. The compound was also characterized by FT-IR and Raman spectrscopies

Experimental Analysis on the Counter-Current Dumitrescu- Taylor Bubble Flow in a Smooth Vertical Conduct of Small Diameter

In this paper, an experimental investigation on the Dumitrescu-Taylor bubble in counter-current laminar downward flow in vertical pipe of a small internal diameter pipe is presented. The experimental design is realized to work for low and stable liquid flow rates. The Dumitrescu-Taylor bubble may be stationary or can be in motion with an ascending or descending velocity, and this displacement depends on the downward liquid flow rates. Consequently, the advantage of this device is to carry out the measurements of the velocities inside the gas Dumitrescu-Taylor bubble by Laser Doppler Velocimetry (LDV). Starting from the visual observations and image acquisitions with a fast camera, a qualitative description was brought on the hydrodynamic behavior of the liquid film and the ripples created at the bottom of the Dumitrescu-Taylor bubble. The experimental results show a presence of a long toroïdal vortex inside the gas bubble. It should be noted that previous work using a hot wire does not show the existence of this vortex. Additionally, other hydrodynamic magnitudes were measured as the liquid film thickness, the Dumitrescu-Taylor bubble rising velocity as well as the erosion bubble. Detailed descriptions are brought concerned this erosion. Strange phenomena have been observed primarily ahead of the nose of bubble and on the side of its end

Vortex Structure in the Wall Region of an Impinging Plane Jet

The work presented here comes within a research program dealing with vortex detection in the impingement region of a planar jet. In this study, experiments have been performed for a submerged turbulent water slot jet impinging normally on a flat plate, and an emphasis was put on the flow field characteristics. For this purpose, particle image velocimetry (PIV) have been employed. A comprehensive fluid mechanical data includes instantaneous and mean flow field, variance of normal and cross velocity fluctuations have been presented. The present work is also concerned with the flow structure in the impingement region where the transfers (heat/mass) occur. An attempt has been made to understand the flow structure by employing the vortex detection criteria on the instantaneous velocity vector field. Accordingly, the PIV measurements were carried out for four different Reynolds numbers: 3000, 6000, 11000 and 16000, and at three different planes: a plane parallel to the impingement plate, transverse plane of the jet and a plane perpendicular to the jet. A method of filtration, based on proper orthogonal decomposition (POD) technique was applied first to the instantaneous velocity and filtered velocity database is then used for vortex detection. Further, the results about the size, shape, spatial distribution and energy content of the detected vortices have been provided

Uncertainty and crude oil returns

We use a copula approach to investigate the effect of uncertainty on crude-oil returns. Using copulas to construct multivariate distributions of time-series data permit the calculation of the dependence structure between the series independently of the marginal distributions. Further, we implement the copula estimation using a rolling window method to allow for a time-varying effect of equity and economic policy uncertainty on oil returns. The results show that higher uncertainty, as measured by equity and economic policy uncertainty indices, significantly increase crude-oil returns only during certain periods of time. That is, we find a positive dependence prior to the financial crisis and Great Recession. Interestingly, estimation of the copula over the entire sample period leads to a negative dependence between the equity and economic policy indices and the crude-oil return.http://www.elsevier.com/locate/eneco2017-03-31hb2016Economic

Germination and growth in control and primed seeds of pepper as affected by salt stress

Salinity is an important abiotic stress which can affect crop production in the world. One of the simplest methods for improving salinity tolerance of plants is seeds priming. This experiment was conducted to evaluate the effects of seeds priming with three solutions (KCl , NaCl and CaCl2) in germination and later growth of three pepper (Capsicum annuum L.) cultivars: Beldi, Baklouti and Anaheim Chili. Seeds germination was conducted in a completely randomized design under seven salinity levels (0, 2, 4, 6, 8, 10 and 12 g L-1) at room temperature for primed and control seeds. Plants derived from these germinated seeds (control and primed) were transplanted and cultivated in a greenhouse for 4 months and were irrigated permanently with seven salinity levels (0, 2, 4, 6, 8, 10 and 12 g L-1). The results showed that salinity affected all parameters under study like total germination percentage and chlorophyll level (a and b). As well, proline content increased as response to increasing salinity. The plants derived and grown from primed seeds showed a considerable tolerance to salt stress and gave better results. In fact, priming improved the salt resistance of pepper owing to more chlorophyll and proline accumulation. These results suggest that seed priming induced possible physiological adjustments in pepper seeds, especially in the early stages of development, and could be used as a suitable tool for improving germination and growth characteristics under salt stress conditions

Observations and Simulations of Electron Dynamics Near an Active Neutral Line

Recent observations in the Earth's magnetotail have shown rapid increases in the fluxes of energetic electrons with energies up to 100's of keV associated with dipolarization fronts that propagate into the inner magnetosphere. On August 15, 2001 the four Cluster spacecraft located slightly dawnward of midnight (yGSM approx. -5.4RE) at xGSM approx. -18RE observed a series of earthward propagating dipolarization fronts [Hwang et al., 2010]. At least 6 dipolarization fronts were observed in a 20m interval. Unlike previously reported cases the fluxes of electrons up to 95keV decreased during the passage of the first three fronts over the spacecraft. The energetic electron fluxes increased during the passage of the last three fronts. We have performed a global magnetohydrodynamic simulation of this event using solar wind observations from the ACE satellite to drive the simulation. In the simulation a very complex reconnection system in the near-Earth tail at XGSM approx. -20RE launched a series of earthward propagating dipolarization fronts that are similar to those observed on Cluster. The simulation results indicate that the Cluster spacecraft were just earthward of the reconnection site. In this paper we will present a study of the dynamics of electrons associated with these events by using the large-scale kinetic simulation approach in which we launch a large number of electrons into the electric and magnetic fields from this simulation

Effects of plyometric and short sprint with change-of-direction training in male U17 soccer players

This project investigated the effect of adding 8 weeks of bi-weekly plyometric and short sprint with change-of-direction (PSSCoD) training into standard training for elite youth soccer players from Tunisia. A training group (n = 18; age: 16.6 ± 0.5 years; body mass: 63.2 ± 4.8 kg; stature: 1.73 ± 0.07 m; body fat: 11.2 ± 1.7%), and control group (n = 16; age: 16.6 ± 0.5 years; body mass: 63.6 ± 4.3 kg; height: 1.73 ± 0.06 m; body fat: 11.6 ± 1.5%) participated. The pre- and post-intervention measures were squat-jump (SJ), countermovement jump (CMJ), standing long jump (SLJ), 5 m and 20 m sprint, change-of-direction ability (4 × 5 m sprint test (S 4 × 5 m)), repeated sprint ability (RSA), and static balance (stork balance test). The training group displayed superior jump (all p < 0.05; d > 0.49), sprint (p < 0.05; d > 0.52), change-of-direction ability (p < 0.01; d = 0.78), RSA (p < 0.01; d > 0.70), and static balance (p < 0.05; d > 0.49) improvements. Adding bi-weekly PSSCoD improves the athletic performance of young soccer players

On the stability of standing waves of Klein-Gordon equations in a semiclassical regime

We investigate the orbital stability and instability of standing waves for two classes of Klein-Gordon equations in the semi-classical regime.Comment: 9 page

Can gold be used as a hedge against the risks of Sharia-compliant securities? Application for Islamic portfolio management

In this paper, we investigate whether gold hedges Sharia-compliant stocks and Sukuk during the period from September 2005 to October 2017. The inference is taken by using both the DCC-GARCH model and the wavelet coherence analysis. On the whole, our finding suggests that gold is not effective in hedging the fluctuations of Sharia-compliant securities. However, we find that combining gold with stocks (and Sukuk) is useful in diversification and portfolio optimization. These results imply that, while gold is an excellent hedge for plain vanilla securities, it is not for Islamic exposures. This is important in light of the increasing amount of assets that are managed according to Islamic screening

Properties of biopolymer dispersions and films used as carriers of the biocontrol agent Candida sake CPA-1

[EN] The use of biocontrol agents (BCA) for controlling plant diseases is an alternative to reduce the use of pesticides. Their performance can be improved when applied in combination with coatings. Films and coatings formulated from different biopolymers were characterized as to their barrier and optical properties to analyse their impact on fruit when applied as carriers of the BCA Candida sake CPA-1. The properties of the film-forming dispersions were more affected by the type of polymer than by the incorporation of surfactants. Sodium caseinate formed the thickest coatings, but these were very thin in every case, which led to there being no predicted relevant effect on the gas exchanges of the fruit. The cell viability in the films was good during film drying, especially in the case of protein films; however, it decreased after storage.The authors are grateful to the Spanish Government for the financial support through project RTA2012-00067-0O2 and to the Conselleria d'Educacio of the Generalitat Valenciana, (Spain) for A. Marin's PhD grant (VALi+d 2013). The authors are also thankful to IRTA group, headed by Dra. Neus Teixido, for their assistance in the microbiological study.Marín-Gozalbo, A.; Atarés Huerta, LM.; Cháfer Nácher, MT.; Chiralt, A. (2017). Properties of biopolymer dispersions and films used as carriers of the biocontrol agent Candida sake CPA-1. LWT - Food Science and Technology. 79:60-69. https://doi.org/10.1016/j.lwt.2017.01.024S60697