Interchange-turbulence-based radial transport model for SOLPS-ITER: A COMPASS case study

Mean-field plasma edge transport codes such as SOLPS-ITER heavily rely on ad-hoc radial diffusion coefficients to approximately model anomalous transport. Such coefficients are experimentally determined and vary between different machines, and also depend on the operational regime and plasma location within the same device. Therefore, to match experimental data the modeller is required to manually tune several free parameters in expensive simulations, and the code's predictive capabilities are significantly downgraded. As a solution, a new model has been developed for SOLPS-ITER, solving an additional transport equation for the turbulent kinetic energy k, derived by consistently time-averaging the Braginskii equations, and including a diffusive closure for the anomalous particle flux. This closure model relates the anomalous diffusion coefficient to the local k value. The resulting equation structure and its closure are inspired by TOKAM2D isothermal interchange turbulence simulation results. Within this model, fewer and hopefully more universal free parameters are retained, thus improving the code's predictive capabilities. The new model has been tested on a COMPASS case for which upstream plasma profiles were available. Experimental data and a reference solution, obtained by matching the profiles through manual tuning of radial diffusivities, have been used to estimate the parameters of our new transport model. A ballooned particle diffusivity profile is retrieved by the new radial transport model, thanks to the proposed interchange drive. The obtained upstream profiles qualitatively agree with the experiment and prove the new model is a promising first attempt to be further refined.     

Toward the Rational Design of Galactosylated Glycoclusters That Target Pseudomonas aeruginosa Lectin A (LecA): Influence of Linker Arms That Lead to Low‐Nanomolar Multivalent Ligands

Anti‐infectious strategies against pathogen infections can be achieved through antiadhesive strategies by using multivalent ligands of bacterial virulence factors. LecA and LecB are lectins of Pseudomonas aeruginosa implicated in biofilm formation. A series of 27 LecA‐targeting glycoclusters have been synthesized. Nine aromatic galactose aglycons were investigated with three different linker arms that connect the central mannopyranoside core. A low‐nanomolar (K_d=19 nm , microarray) ligand with a tyrosine‐based linker arm could be identified in a structure–activity relationship study. Molecular modeling of the glycoclusters bound to the lectin tetramer was also used to rationalize the binding properties observed.     

Model independent bounds on reaction cross-sections in heavy-ion scattering

The coupled cluster equations first proposed by Coester and Kümmel and developed by Kümmel, Lührmann, and Zabolitsky are derived explicitly from the variational principle for the ground state energy (the “true” energy) using a new set of simple formulas relating density matrices (equal time limits of Green functions) to the coupled cluster functions. In this respect a simplification appears to be achieved by working with a normalized ground state wave function. The further transformation of the variational equations into the standard forms given by the previous authors differs mainly in its pedagogical aspects from ideas found in the existing literature.     

A test of factorization methods in coupled channel reaction theory

Factorization methods used in shell-model approaches to nuclear reactions provide a good starting point for perturbative treatments of direct coupling. General algebraic equations are given for zero and higher orders. Problems of convergence of the Born series are tested with a soluble model. It is shown that the zero-order approximation is quite good. First- and second-order corrections are calculated and exhibit a rapid convergence. The influence of parameters entering in factorization formulae is discussed.     

Rare earth doped α-alumina thin films prepared by pulsed laser deposition: structural and optical properties

-Al₂O₃ films doped with about 1% Eu³⁺ were grown on sapphire (012) substrates by pulsed laser deposition using an ArF excimer laser under 10^-4 mbar oxygen pressure and at temperatures higher than 1050 °C. The Eu doping rate was measured by Rutherford backscattering spectroscopy. The crystalline structure was determined by X-ray diffraction and transmission electron microscopy. The films are grown epitaxially on the sapphire substrate. The Eu³⁺ fluorescence spectra are constituted of narrow lines. By means of pulsed laser deposition, Eu³⁺ ions may be introduced into a single site of the -phase lattice, with a concentration that cannot be reached using conventional crystal-growth methods. PACS 81.15.Fg; 68.37.Lp; 78.55.Hx     

Horizon Entropy

Although the laws of thermodynamics are well established for black hole horizons, much less has been said in the literature to support the extension of these laws to more general settings such as an asymptotic de Sitter horizon or a Rindler horizon (the event horizon of an asymptotic uniformly accelerated observer). In the present paper we review the results that have been previously established and argue that the laws of black hole thermodynamics, as well as their underlying statistical mechanical content, extend quite generally to what we call here causal horizons. The root of this generalization is the local notion of horizon entropy density.     

Reductive cyclizations of hydroxysulfinyl ketones: enantioselective access to tetrahydropyran and tetrahydrofuran derivatives

The stereocontrolled formation of cis-2,5-disubstituted tetrahydrofurans and cis-2,6-disubstituted tetrahydropyrans is achieved from enantiopure ketosulfinyl esters by reduction, Weinreb's amide, and ketone formation, followed by the reductive cyclization (Et3SiH/TMSOTf) of the resulting hydroxysulfinyl ketones. The sulfoxide-bearing heterocycles were transformed into two natural products, (-)-centrolobine (1) and both enantiomers of cis-(6-methyltetrahydropyran-2-yl)acetic acid (2).