The Cyprus Institute

About: The Cyprus Institute is a other organization based out in Nicosia, Cyprus. It is known for research contribution in the topics: Aerosol & Environmental science. The organization has 418 authors who have published 1252 publications receiving 32586 citations.

Recrossing and Tunneling in the Kinetics Study of the OH + CH4 → H2O + CH3 Reaction.

Abstract: Thermal rate constants and several kinetic isotope effects were evaluated for the OH + CH4 hydrogen abstraction reaction using two kinetics approaches, ring polymer molecular dynamics (RPMD) and variational transition state theory with multidimensional tunneling (VTST/MT), based on a refined full-dimensional analytical potential energy surface, PES-2014, in the temperature range 200–2000 K For the OH + CH4 reaction, at low temperatures, T = 200 K, where the quantum tunneling effect is more important, RPMD overestimates the experimental rate constants due to problems associated with PES-2014 in the deep tunneling regime and to the known overestimation of this method in asymmetric reactions, while VTST/MT presents a better agreement, differences about 10%, due to compensation of several factors, inaccuracy of PES-2014, and ignoring anharmonicity In the opposite extreme, T = 1000 K, recrossing effects play the main role, and the difference between both methods is now smaller, by a factor of 15 Given that

Gluon momentum fraction of the nucleon from lattice QCD

Abstract: We perform a direct calculation of the gluon momentum fraction of the nucleon, taking into account the mixing with the corresponding quark contribution. We use maximally twisted mass fermion ensembles with ${N}_{f}=2+1+1$ flavors at a pion mass of about 370 MeV and a lattice spacing of $a\ensuremath{\approx}0.082\text{ }\text{ }\mathrm{fm}$ and with ${N}_{f}=2$ flavors at the physical pion mass and a lattice spacing of $a\ensuremath{\approx}0.093\text{ }\text{ }\mathrm{fm}$. We employ stout smearing to obtain a statistically significant result for the bare matrix elements. In addition, we perform a lattice perturbative calculation including two levels of stout smearing to carry out the mixing and the renormalization of the quark and gluon operators. We find, after conversion to the $\overline{\mathrm{MS}}$ scheme at a scale of 2 GeV, $⟨x{⟩}_{g}^{R}=0.284(27)(17)(24)$ for pion mass of about 370 MeV and $⟨x{⟩}_{g}^{R}=0.267(22)(19)(24)$ for the physical pion mass. In the reported numbers, the first parenthesis indicates statistical uncertainties. The numbers in the second and third parentheses correspond to systematic uncertainties due to excited states contamination and renormalization, respectively.

Changing Energy Requirements in the Mediterranean Under Changing Climatic Conditions

Abstract: This study investigates the impacts of climate change on energy requirements in the Mediterranean. Energy requirements, especially for space heating and cooling, are closely linked to several weather variables, mainly air temperature. The analysis is based on daily temperature outputs from several regional climate models run at a resolution of 25 km × 25 km in the framework of EU project ENSEMBLES using the A1B emissions scenario. The impacts of changes in temperature on energy requirements are investigated using the concept of degree days, defined as the difference of mean air temperature from a base temperature. Base temperature should be chosen to coincide with the minimum energy consumption. In this way, changes in heating and cooling requirements between the reference and the future period are calculated and areas about to undergo large changes identified. These changes are calculated between a 30-year reference period 1961-1990 and a near future period 2021-2050 taking the ensemble mean of all regional climate models. The near-term future has been chosen instead of the frequently used end-of-the-century period to assist policy makers in their planning. In general, a decrease in energy requirements is projected under future milder winters and an increase under hotter summers.

$\langle x\rangle$ and $\langle x^2\rangle$ of the pion PDF from Lattice QCD with $N_f=2+1+1$ dynamical quark flavours

Abstract: Using ${N}_{f}=2+1+1$ lattice QCD, we determine the fermionic connected contributions to the first and second moments of the pion parton distribution function. Based on gauge configurations from the European Twisted Mass Collaboration, chiral and continuum extrapolations are performed using pion masses in the range of 230 to 500 MeV and three values of the lattice spacing. Finite volume effects are investigated using different volumes. In order to avoid mixing under renormalization for the second moment, we use an operator with two nonzero spatial components of momentum. Momenta are injected using twisted boundary conditions. Our final values read $⟨x{⟩}_{\mathrm{R}}^{\mathrm{phys}}=0.2075(106)$ and $⟨{x}^{2}{⟩}_{\mathrm{R}}^{\mathrm{phys}}=0.163(33)$, determined at 2 GeV in the $\overline{\mathrm{MS}}$ scheme and with systematic and statistical uncertainties summed in quadrature.

Mechanisms of failure on terraced slopes: the Valtellina case (northern Italy)

Abstract: Slopes that are terraced by means of dry-stone retaining walls are very common in the alpine environment In Valtellina, a typical Italian alpine valley, these slopes are widespread and quite often involved in superficial mass movements that can result in severe damage and casualties For an in-depth understanding of the processes that can trigger these events, numerical modeling of groundwater movement and a related stability analysis were performed on a detailed scale, based on an intensive monitoring of rainfall events and groundwater movement Field observations suggest that the formation of a perched groundwater table at the contact between the bedrock and the backfill soil of walls as well as the concomitant saturation of this backfill soil are the determining factors of potential slope failure The numerical models support these observations In addition, the models are able to explain the mechanisms of formation of perched water tables, highlighting the factors that can influence groundwater levels and slope instabilities