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.

3D enhanced model from multiple data sources for the analysis of the cylinder seal of Ibni-Sharrum

Abstract: In this paper we present the result of the integration of multiple data sources of different 3D acquisition techniques. These acquisitions have been done in order to create a new way to document works of art that have been applied to the "Cylinder seal of Ibni-Sharrum". X-ray tomography has been used to reveal the exact position of inclusions and the presence fissure in the mineral structure; optical micro topography gives the prints of the surface of the seal with a unparallelled precision of up to 0.1μm. Finally a lower resolution 3D model obtained via photogrammetry has been used as a starting point where the tomographic and micro topographic data sets have been superimposed and integrated without precision loss. Furthermore, the textures obtained from HDR photographs has been registered and merged onto the high resolution mesh. These methods have pros and cons that will be discussed and the final obtained model will be the sum of all the complementary cons. The final result of this interdisciplinary investigation will help the curator to better describe the fabrication techniques used in order to achieve the final object and a contemporary artist to do a reproduction of the cylinder at a scale of 1000:1.

Chemical Reaction Rate Coefficients from Ring Polymer Molecular Dynamics: Theory and Practical Applications

Abstract: This Feature Article presents an overview of the current status of ring polymer molecular dynamics (RPMD) rate theory. We first analyze the RPMD approach and its connection to quantum transition-state theory. We then focus on its practical applications to prototypical chemical reactions in the gas phase, which demonstrate how accurate and reliable RPMD is for calculating thermal chemical reaction rate coefficients in multifarious cases. This review serves as an important checkpoint in RPMD rate theory development, which shows that RPMD is shifting from being just one of recent novel ideas to a well-established and validated alternative to conventional techniques for calculating thermal chemical rate coefficients. We also hope it will motivate further applications of RPMD to various chemical reactions.

Pion and kaon ⟨ x 3 ⟩ from lattice QCD and PDF reconstruction from Mellin moments

Abstract: We present a calculation of the pion and kaon Mellin moment $⟨{x}^{3}⟩$ extracted directly in lattice QCD using a three-derivative local operator. We use one ensemble of gauge configurations with two degenerate light, a strange and a charm quark (${N}_{f}=2+1+1$) of maximally twisted mass fermions with clover improvement. The ensemble reproduces a pion mass $\ensuremath{\sim}260\text{ }\text{ }\mathrm{MeV}$, and a kaon mass $\ensuremath{\sim}530\text{ }\text{ }\mathrm{MeV}$. Excited-states contamination is evaluated using four values of the source-sink time separation within the range of 1.12--1.67 fm. We use an operator that is free of mixing, and apply a multiplicative renormalization function calculated nonperturbatively. Our results are converted to the $\overline{\mathrm{MS}}$ scheme and evolved at a scale of 2 GeV, using three-loop expressions in perturbation theory. The final values are $⟨{x}^{3}{⟩}_{\ensuremath{\pi}}^{{u}^{+}}=0.024(18{)}_{\mathrm{stat}}(2{)}_{\mathrm{syst}}$, $⟨{x}^{3}{⟩}_{K}^{{u}^{+}}=0.035(6{)}_{\mathrm{stat}}(3{)}_{\mathrm{syst}}$, and $⟨{x}^{3}{⟩}_{K}^{{s}^{+}}=0.075(5{)}_{\mathrm{stat}}(1{)}_{\mathrm{syst}}$, where the systematic error is the uncertainty due to excited state contamination. We combine $⟨{x}^{3}⟩$ with the two lower moments, namely $⟨x⟩$ and $⟨{x}^{2}⟩$, to obtain the ratios $⟨{x}^{3}⟩/⟨x⟩$ and $⟨{x}^{3}⟩/⟨{x}^{2}⟩$, as well as $⟨{x}^{3}{⟩}_{K}^{{u}^{+}}/⟨{x}^{3}{⟩}_{\ensuremath{\pi}}^{{u}^{+}}$ and $⟨{x}^{3}{⟩}_{K}^{{u}^{+}}/⟨{x}^{3}{⟩}_{\ensuremath{\pi}}^{{u}^{+}}$. In addition, we reconstruct the $x$-dependence of the pion and kaon PDFs via 2- and 3-parameter fits to our results. We find that the reconstruction is feasible and that our lattice data favor a large $x$-dependence that falls as $(1\ensuremath{-}x{)}^{2}$ for both the pion and kaon PDFs. We integrate the reconstructed PDFs to extract the higher moments with $4\ensuremath{\le}n\ensuremath{\le}6$. Finally, we compare the pion and kaon PDFs, as well as the ratios of their moments, to address the effect of SU(3) flavor symmetry breaking.

Aerosol sources in the western Mediterranean during summertime: a model-based approach

Abstract: . In the framework of ChArMEx (the Chemistry-Aerosol Mediterranean Experiment), the air quality model Polyphemus is used to understand the sources of inorganic and organic particles in the western Mediterranean and evaluate the uncertainties linked to the model parameters (meteorological fields, anthropogenic and sea-salt emissions and hypotheses related to the model representation of condensation/evaporation). The model is evaluated by comparisons to in situ aerosol measurements performed during three consecutive summers (2012, 2013 and 2014). The model-to-measurement comparisons concern the concentrations of PM 10 , PM 1 , organic matter in PM 1 (OM 1 ) and inorganic aerosol concentrations monitored at a remote site (Ersa) on Corsica Island, as well as airborne measurements performed above the western Mediterranean Sea. Organic particles are mostly from biogenic origin. The model parameterization of sea-salt emissions has been shown to strongly influence the concentrations of all particulate species (PM 10 , PM 1 , OM 1 and inorganic concentrations). Although the emission of organic matter by the sea has been shown to be low, organic concentrations are influenced by sea-salt emissions; this is owing to the fact that they provide a mass onto which gaseous hydrophilic organic compounds can condense. PM 10 , PM 1 , OM 1 are also very sensitive to meteorology, which affects not only the transport of pollutants but also natural emissions (biogenic and sea salt). To avoid large and unrealistic sea-salt concentrations, a parameterization with an adequate wind speed power law is chosen. Sulfate is shown to be strongly influenced by anthropogenic (ship) emissions. PM 10 , PM 1 , OM 1 and sulfate concentrations are better described using the emission inventory with the best spatial description of ship emissions (EDGAR-HTAP). However, this is not true for nitrate, ammonium and chloride concentrations, which are very dependent on the hypotheses used in the model regarding condensation/evaporation. Model simulations show that sea-salt aerosols above the sea are not mixed with background transported aerosols. Taking the mixing state of particles with a dynamic approach to condensation/evaporation into account may be necessary to accurately represent inorganic aerosol concentrations.