6,600 research outputs found
The spin alignment of galaxies with the large-scale tidal field in hydrodynamic simulations
The correlation between the spins of dark matter halos and the large-scale
structure (LSS) has been studied in great detail over a large redshift range,
while investigations of galaxies are still incomplete. Motivated by this point,
we use the state-of-the-art hydrodynamic simulation, Illustris-1, to
investigate mainly the spin--LSS correlation of galaxies at redshift of .
We mainly find that the spins of low-mass, blue, oblate galaxies are
preferentially aligned with the slowest collapsing direction () of the
large-scale tidal field, while massive, red, prolate galaxy spins tend to be
perpendicular to . The transition from a parallel to a perpendicular trend
occurs at in the stellar mass, in the g-r
color, and in triaxiality. The transition stellar mass decreases with
increasing redshifts. The alignment was found to be primarily correlated with
the galaxy stellar mass. Our results are consistent with previous studies both
in N-body simulations and observations. Our study also fills the vacancy in the
study of the galaxy spin--LSS correlation at using hydrodynamical
simulations and also provides important insight to understand the formation and
evolution of galaxy angular momentum.Comment: 9 pages, 6 figures, 1 table. Accepted for publication in ApJ, match
the proof versio
Pore-scale simulation of multicomponent multiphase reactive transport with dissolution and precipitation
Multicomponent multiphase reactive transport processes with
dissolution-precipitation are widely encountered in energy and environment
systems. A pore-scale two-phase multi-mixture model based on the lattice
Boltzmann method (LBM) is developed for such complex transport processes, where
each phase is considered as a mixture of miscible components in it. The
liquid-gas fluid flow with large density ratio is simulated using the
multicomponent multiphase pseudo-potential LB model; the transport of certain
solute in the corresponding solvent is solved using the mass transport LB
model; and the dynamic evolutions of the liquid-solid interface due to
dissolution-precipitation are captured by an interface tracking scheme. The
model developed can predict coupled multiple physicochemical processes
including multiphase flow, multicomponent mass transport, homogeneous reactions
in the bulk fluid and heterogeneous dissolution-precipitation reactions at the
fluid-solid interface, and dynamic evolution of the solid matrix geometries at
the pore-scale. The model is then applied to a physicochemical system
encountered in shale gas/oil industry involving multiphase flow, multicomponent
reactive transport and dissolution-precipitation, with several reactions whose
rates can be several orders of magnitude different at a given temperature. The
pore-scale phenomena and complex interaction between different sub-processes
are investigated and discussed in detail
Reactive organoallyl species generated from aryl halides and allene: allylation of alpha,beta-unsaturated aldehydes and cyclic ketones employing Pd/In transmetallation processes
Allylation of α,β-unsaturated aldehydes and cyclic ketones promoted by Pd/In transmetallation processes has been studied. The unsaturated aldehydes underwent regioselective 1,2-addition to afford secondary homoally alcohols. The reactions have been performed using Pd(OAc)2/PPh3 as catalytic system and metallic indium affording the products in good yields. The same transformation with unsaturated ketones proved to be less efficient, while saturated cyclic ketones delivered generally excellent yields in the presence of CuI. In these latter processes the presence of a distal heteroatom influences the reaction rate
Fysisk prestation och matchkrav inom elitfotboll - Samband mellan smålagsspel och de mest intensiva perioder inom fotboll
De fysiska kraven hos elitfotbollsspelare är stora och såväl aerob som anaerob förmåga är viktiga för prestationen. Individuella skillnader i fysisk kapacitet spelare emellan är välkänt men individuell träningsplanering med lämplig belastning för att optimera spelares enskilda behov är inte lika väl studerat. Syftet med denna studie är att undersöka sambandet mellan spelares matchkrav i fotboll i form av högintensiva perioder (peakperioder) och träningsrespons på smålagsspel. Vi har studerat individuella spelares högintensiva perioder i match, olika typer av smålagsspel (4v4, 6v6 och 8v8) och andra fysiska tester. Studien har en kvantitativ experimentell design där GPS-data i fotboll är analyserad. 17 elitfotbollsspelare (Ålder 23.7 ± 4.8 år, vikt 76.4 ± 4.8 kg, längd 181.1 ± 5.2 cm) från allsvenskan och superettan i svensk herrfotboll deltog i studien. Resultaten visar att olika typer av smålagsspel belastar spelarna på olika sätt, där vissa fysiska variabler har ett medel (>0.30) till stark korrelation (>0.70), medan andra variabler visar en svag (>0.10) till ingen korrelation (<0.10). Sambandet mellan fysiska tester och matchkrav i form av peakperioder visar att endast Repeated Sprint Ability (RSA) kan ha en relevant användning för att förutse prestation i peakperioder. Information om vilken typ av smålagsspel som har vilken effekt och hur de belastar spelaren samt matchkrav på individ- och gruppnivå kan underlätta för tränaren vid utformning av träningsplanering. Slutligen krävs mer forskning inom området för att säkerhetsställa att tillämpningen av smålagsspel samt de fysiska testerna, gentemot matchkraven i form av peakperioder, blir så matchlik och optimal som möjligt
Electrochemical Characterization of Clean Shape-Controlled Pt Nanoparticles Prepared in Presence of Oleylamine/Oleic Acid
A collection of shape-controlled Pt nanoparticles has been prepared using two different and previously described methodologies, both using oleylamine/oleic acid as capping material/solvent. A new decontamination protocol is presented to effectively clean the surface of the different nanoparticles thus allowing a full exposure of their surface area and consequently to make the most of their surface structure dependent reactivity. Subsequently, the clean shape-controlled Pt nanoparticles have been electrochemically characterized and their electrocatalytic properties evaluated towards some surface structure reactions of interest. The results indicate that the full characterization of the surface structure cannot be done exclusively by the available microscopy techniques, since it is very difficult to determine the presence of surface defects. Additional surface characterization probes, such as those provided by electrochemical surface sensitive reactions, have been used to assess the surface structure of the samples.This work has been financially supported by the MICINN (Feder) of Spain and Generalitat Valencia through Projects CTQ2013-44083-P and PROMETEOII/2014/013, respectively
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