LLE data for the ionic liquid 3-methyl-N-butyl pyridinium dicyanamide with several aromatic and aliphatic hydrocarbons

(Liquid + liquid) equilibrium data for ternary systems of several aromatic and aliphatic hydrocarbons with the ionic liquid 3-methyl-N-butylpyridinium dicyanamide were determined at T = 303.15 K and 328.15 K and atmospheric pressure. As aromatics benzene, cumene and p-xylene have been chosen, as paraffins n-hexane and n-nonane were used. The experimental data were regressed and could be adequately correlated with the NRTL model. A logical order in the extraction capacity of 3-methyl-N-butylpyridinium dicyanamide for the different aromatics is obtained: benzene > p-xylene > cumene.     

Forward and inverse problems in fundamental and applied magnetohydrodynamics

This minireview summarizes the recent efforts to solve forward and inverse problems as they occur in different branches of fundamental and applied magnetohydrodynamics. For the forward problem, the main focus is on the numerical treatment of induction processes, including self-excitation of magnetic fields in non-spherical domains and/or under the influence of non-homogeneous material parameters. As an important application of the developed numerical schemes, the functioning of the von-Kármán-sodium (VKS) dynamo experiment is shown to depend crucially on the presence of soft-iron impellers. As for the inverse problem, the main focus is on the mathematical background and some initial practical applications of contactless inductive flow tomography (CIFT), in which flow induced magnetic field perturbations are utilized to reconstruct the velocity field. The promises of CIFT for flow field monitoring in the continuous casting of steel are substantiated by results obtained at a test rig with a low-melting liquid metal. While CIFT is presently restricted to flows with low magnetic Reynolds numbers, some selected problems from non-linear inverse dynamo theory, with possible applications to geo- and astrophysics, are also discussed.     

Measuring heat transfer during spray cooling using controlled induction-heating experiments and computational models

This paper presents a methodology combining experimental measurements with computational modeling to find the heat flux extracted during spray cooling of a metal surface. Controlled experiments are performed to impinge air-mist spray onto a metal probe surface while applying induction heating to follow a desired temperature history. A transient axisymmetric computational model of induction heating which couples electromagnetics and heat conduction has been developed and validated with a test problem. The model is calibrated to match transient dry measurements and then used to simulate a steady-state air-mist spray cooling experiment in order to quantify the heat extracted from the probe surface by the boiling water droplets. A detailed example is presented to illustrate this approach.     

Nodal Domains of Maass Forms I

This paper deals with some questions that have received a lot of attention since they were raised by Hejhal and Rackner in their 1992 numerical computations of Maass forms. We establish sharp upper and lower bounds for the L ²-restrictions of these forms to certain curves on the modular surface. These results, together with the Lindelof Hypothesis and known subconvex L ^∞-bounds are applied to prove that locally the number of nodal domains of such a form goes to infinity with its eigenvalue.     

A fuzzy difference equation with an application

Difference equations arise in the modeling of many interesting problems. “Measurements” of data or specified information for an underlying problem may be imprecise or only partially specified. This motivates us to initiate a study of “fuzzy difference equations.” In this paper, we will formulate and solve a given difference equation in the fuzzy setting and give a general method for dealing with any first order difference equation.     

Desorption electrospray ionization and electrosonic spray ionization for solid- and solution-phase analysis of industrial polymers

Desorption electrospray ionization (DESI) and electrosonic spray ionization (ESSI), two new techniques, are used to measure average molecular weights and molecular weight distributions of solid-phase and solution-phase samples of the same polymers.     

Open computing grid for molecular science and engineering

Grid is an emerging infrastructure for distributed computing that provides secure and scalable mechanisms for discovering and accessing remote software and data resources. Applications built on this infrastructure have great potential for addressing and solving large scale chemical, pharmaceutical, and material science problems. The article describes the concept behind grid computing and will present the OpenMolGRID system that is an open computing grid for molecular science and engineering. This system provides grid enabled components, such as a data warehouse for chemical data, software for building QSPR/QSAR models, and molecular engineering tools for generating compounds with predefined chemical properties or biological activities. The article also provides an overview about the availability of chemical applications in the grid.     

Improved Boussinesq-type equations for highly variable depth

^** Email: jcarlmz{at}yahoo.com^*** Email: nachbin{at}impa.br Intermediate-depth, Boussinesq-type modelling is used to generalizepreviously known results for surface water waves propagatingover arbitrarily shaped topographies. The improved reduced wavemodel is obtained after studying how small changes in the lineardispersion relation (over a flat bottom) can become dramaticallyimportant in the presence of a highly fluctuating topography.Numerical validation of the dispersive properties, regardingseveral possible truncations for the reduced models, are comparedwith the complete (non-truncated) linear potential theory model.Moreover, linear L²-estimates are extended from the analysisof KdV-type models to include the improved Boussinesq systemsin contrast with potential theory. Discrepancies observed amongthe different possible reduced models become even more importantin the wave-form inversion problem. The time reversal techniqueis used for recompressing a long fluctuating signal, representinga highly scattered wave that has propagated for very long distances.When properly back-propagated (through a numerical model), thescattered signal refocuses into a smooth profile representingthe onset of the ocean's surface disturbance. Previous Boussinesqmodels underestimate the original disturbance's amplitude. Theimproved Boussinesq system agrees very well with the full potentialtheory predictions.     

On the Frobenius stable part of Witt vector cohomology

For a proper (not necessarily smooth) variety over a finite field with q elements, Berthelot?CBloch?CEsnault proved a trace formula which computes the number of rational points modulo q in terms of the Witt vector cohomology. We show the analogous formula for Witt vector cohomology of finite length. In addition, we prove a vanishing result for the compactly supported étale cohomology of a constant p-torsion sheaf on an affine Cohen?CMacaulay variety.