SR XRF and micro-PIXE studies on ancient metallurgy of thirteen Dacian gold bracelets

A thorough microscopic investigation by SR XRF and micro-PIXE brings insight into the probable techniques used in the manufacture of thirteen Dacian gold bracelets, one of the most spectacular archaeological finds ever on the territory of Romania.     

Existence Results for the Flow of Viscoelastic Fluids with an Integral Constitutive Law

We consider the flows of viscoelastic fluid which obey a constitutive law of integral type. Some theoretical results are proved: local existence, global existence with small data and uniqueness results for the initial boundary value problem.     

Microwave-assisted conversion of carbohydrates. State of the art and outlook

The valorisation of carbohydrates arising from the hydrolysis of renewable feedstocks (i.e., lignocellulosic biomass) is nowadays an area of utmost interest. In this context, the implementation of fast, expeditious and cost-effective methodologies for the modification of these naturally occurring compounds is becoming a prerequisite. With this aim, the application of microwaves has gained progressive attention in laboratories for making a range of high-added value sugars derivative scaffolds. The advantages of microwaves are numerous, and include enhancement of reaction rates and yields, combined with improved regio-, chemo- and anomeric selectivities.     

Asymptotic behavior of degenerate linear transport equations

We study in this paper a few simple examples of hypocoercive systems in which the coercive part is degenerate. We prove that the (completely explicit) speed of convergence is at least of inverse power type (the power depending on the features of the considered system).     

Instabilities for supercritical Schrödinger equations in analytic manifolds

In this paper we consider supercritical nonlinear Schrödinger equations in an analytic Riemannian manifold (Md,g), where the metric g is analytic. Using an analytic WKB method, we are able to construct an Ansatz for the semiclassical equation for times independent of the small parameter. These approximate solutions will help to show two different types of instabilities. The first is in the energy space, and the second is an immediate loss of regularity in higher Sobolev norms.     

Optimization of capacity expansion planning for gas transportation networks

This paper presents techniques for solving the problem of minimizing investment costs on an existing gas transportation network. The goal of this program is to find, first, the optimal location of pipeline segments to be reinforced and, second, the optimal sizes (among a discrete commercial list of diameters) under the constraint of satisfaction of demands with high enough pressure for all users.     

Rigidity of Poisson structures

We study germs of analytic Poisson structures which are suitable perturbations of a quasihomogeneous Poisson structure in a neighborhood of the origin of ℝ ⁿ or ℂ ⁿ , a fixed point of the Poisson structures. We define a “diophantine condition” relative to the quasihomogeneous initial part ie256-1 which ensures that such a good perturbation of 256-2 which is formally conjugate to 256-3 is also analytically conjugate to it.