A Wasserstein approach to the one-dimensional sticky particle system

We present a simple approach to study the one-dimensional pressureless Euler system via adhesion dynamics in the Wasserstein space of probability measures with finite quadratic moments. Starting from a discrete system of a finite number of "sticky" particles, we obtain new explicit estimates of the solution in terms of the initial mass and momentum and we are able to construct an evolution semigroup in a measure-theoretic phase space, allowing mass distributions with finite quadratic moment and corresponding L^2-velocity fields. We investigate various interesting properties of this semigroup, in particular its link with the gradient flow of the (opposite) squared Wasserstein distance. Our arguments rely on an equivalent formulation of the evolution as a gradient flow in the convex cone of nondecreasing functions in the Hilbert space L^2(0,1), which corresponds to the Lagrangian system of coordinates given by the canonical monotone rearrangement of the measures.Comment: Added reference

Contraction of general transportation costs along solutions to Fokker-Planck equations with monotone drifts

We shall prove new contraction properties of general transportation costs along nonnegative measure-valued solutions to Fokker–Planck equations, when the drift is a monotone operator. A new duality approach to contraction estimates has been developed: it relies on the Kantorovich dual formulation of optimal transportation problems and on a variable-doubling technique. The latter is used to derive a new comparison property of solutions of the backward Kolmogorov (or dual) equation. This technique directly applies to distributional solutions without requiring stronger regularity, and it extends the Wasserstein theory of Fokker–Planck equations with gradient drift terms, started by Jordan, Kinderlehrer and Otto (1998), to more general costs and monotone drifts, without requiring the drift to be a gradient and without assuming any growth conditions

Ageing of lanthanum strontium copper orthoferrite powders for sensing layers

Nanosized powders of lanthanum strontium copper orthoferrites La0.8Sr0.2Fe1-xCuxO3-w(LSFC) have been recently proposed as sensing component in chemical sensors for humidity detection. The LSFC powders were prepared by citrate auto-combustion of dry gel obtained from a solution of corresponding nitrates in a citric acid solution. The aged powders were investigated by chemical and structural analysis using X-ray Photoelectron Spectroscopy (XPS), Infrared Spectroscopy and X-Ray Powder Diffraction as a total loss of their sensing properties has been observed after about one year storage of the sensors at room temperature in the laboratory. The detection of surface hydroxides and carbonates species as well as very large Sr and Cu excess within the surface area were important results. Copyright © 2015, AIDIC Servizi S.r.l

C60@Lysozyme: Direct observation by nuclear magnetic resonance of a 1:1 fullerene protein adduct

Integrating carbon nanoparticles (CNPs) with proteins to form hybrid functional assemblies is an innovative research area with great promise for medical, nanotechnology, and materials science. The comprehension of CNP-protein interactions requires the still-missing identification and characterization of the 'binding pocket' for the CNPs. Here, using Lysozyme and C-60 as model systems and NMR chemical shift perturbation analysis, a protein-CNP binding pocket is identified unambiguously in solution and the effect of the binding, at the level of the single amino acid, is characterized by a variety of experimental and computational approaches. Lysozyme forms a stoichiometric 1:1 adduct with C-60 that is dispersed monomolecularly in water. Lysozyme maintains its tridimensional structure upon interaction with C-60 and only a few identified residues are perturbed. The C-60 recognition is highly specific and localized in a well-defined pocket

Coprecipitation of Oxalates: An Easy and Reproducible Wet-Chemistry Synthesis Route for Transition-Metal Ferrites

In this work, an easy, quick and reproducible wet-synthesis coprecipitation route starting from oxalate precursors was optimised to synthesise cobalt, nickel, zinc and magnesium spinel ferrites CoFe2O4, NiFe2O4, ZnFe2O4 and MgFe2O4, as well as the manganese perovskite ferrite MnFeO3. Crystalline purity and crystallite sizes ranging from 30 to 190 nm were investigated by means of powder X-ray diffraction, and uniform morphology of the particles was shown through transmission electron microscopy. The chosen synthetic route afforded an excellent stoichiometric control over the products, as confirmed by combined X-ray photoelectron spectroscopy and inductively coupled plasma atomic emission spectroscopy analyses. The site geometry, degree of inversion in the spinels and chemical environments in the ferrites were explored by M\uf6ssbauer spectroscopy. The thermal evolution of the compounds during calcination and the decomposition pattern of the oxalates were studied through differential scanning calorimetry coupled with thermogravimetric analysis as well as in situ temperature-programmed X-ray diffraction. Magnetic properties of these oxides, as well as the transition of the perovskite from paramagnetic to ferrimagnetic behaviour at low temperatures, were investigated by superconducting quantum interferometer magnetometr