Scaling,propagation, and kinetic roughening of flame fronts in random media

We introduce a model of two coupled reaction-diffusion equations to describe the dynamics and propagation of flame fronts in random media. The model incorporates heat diffusion, its dissipation, and its production through coupling to the background reactant density. We first show analytically and numerically that there is a finite critical value of the background density below which the front associated with the temperature field stops propagating. The critical exponents associated with this transition are shown to be consistent with meanfield theory of percolation. Second, we study the kinetic roughening associated with a moving planar flame front above the critical density. By numerically calculating the time-dependent width and equal-time height correlation function of the front, we demonstrate that the roughening process belongs to the universality class of the Kardar-Parisi-Zhang interface equation. Finally, we show how this interface equation can be analytically derived from our model in the limit of almost uniform background density.     

Electronic and structural properties of Si10 cluster

Possible structures for Si₁₀ cluster are considered using a tight-binding model and drawing on significant work done in the past. It is shown that the tight-binding parametrization, fitted to the bulk, is also valid for smaller systems. This model is found to essentially reproduce other published results, but requires much less effort thanab initio techniques—thus, allowing the study of a wide variety of structures and their ions. However, unlike classical force-field calculations, it yields information about the electronic structure of clusters. A new geometric structure for Si₁₀ is found, which is not only of lowest energy, but which also matches the experimental photoelectron band gap and explains the experimental reactivity data. Because of the Jahn-Teller effect, the photoelectron spectrum is very sensitive to geometry. Also, ionization of the cluster alters the geometry slightly.     

Synthesis of 9-Alkyl- and 9-Arylthiophenanthrenes

A simple method for the preparation of 9-alkyl- and 9-arylthio-phenanthrenes from 9-bromophenanthrene and a thiol is described.     

On modeling the dissolution of sedimentary rocks in acidic environments. An overview of selected mathematical methods with presentation of a case study

Different environmental processes utilize calcium carbonate and sedimentary rocks, for instance sedimentary rocks are used for water purification as filters and utilized also for acid remediation of process waters before being discarded. Additionally sedimentary rocks are used in another very important environmental process, wet Flue Gas Desulfurization. In this process, limestone and carbonates in general play one important role because of their dissolution and provision of the necessary amount of calcium ions used for the precipitation of gypsum. The objective of this study is to present in a first place an overview of a reduced number of specific theoretical and empirical mathematical models applied to the dissolution of carbonates in acidic environments with provision of additional developments and details, secondly a case study was presented where a suitable time of exposure and surface diffusivity obtained analytically by different methods well describe the experimental results. There were justifications for this choice. The experimental data and the related mathematical modeling were performed considering transient conditions. In the present work diverse raw materials were tested in order to reveal their suitability for wet Flue Gas Desulfurization. The research was focused on products from $\text{ CO }_{2}$ CO 2 fixation processes materials as well as other types of limestone samples. In this way it was found that also waste materials from different environmental processes, like $\text{ CO }_{2}$ CO 2 fixation can be used for Flue Gas Desulfurization.     

Utilization of cascade chemo-bio catalysis for the synthesis of R -1-phenylethyl acetate

Liquid phase tert-butylation of m-cresol was carried out using 12-tungstosilicic acid supported on neutral alumina by varying different parameters. The reaction has also been carried out by using calcined samples under optimized conditions. The present catalyst shows an excellent activity of 93.2%, conversion of 100% selectivity for the o-isomer, an important industrial product.     

Influence of aqueous aging on surface properties of plasma sprayed oxide coatings

The influence of aging in mild aqueous conditions (pH 4, 7 and 9) on surface properties of plasma sprayed oxide was studied using electrophoretic mobility studies and measuring concentrations of dissolved species from exposure liquids. In addition, required acid/base additions to maintain constant pH, redox potentials suspension conductivities were measured. The experiment time was two weeks. The plasma sprayed materials were based on Al(2)O(3), TiO(2) and Cr(2)O(3). Materials based on Al(2)O(3) dissolved easily at pH 4 due to presence of metastable gamma-Al(2)O(3) phase. In addition there was clear change in surface charging properties (zeta potential) of Al(2)O(3) surfaces so that the estimated IEP value drifted from >9 at the beginning of aging and dropped down to 8.5-8.7 after 2 weeks of treatment. Plasma sprayed TiO(2) did not dissolve under the experiment conditions. Even thought the surface charging (zeta potential) changed during the exposure, the estimated IEP remained close to the values reported for pure TiO(2) materials. Plasma sprayed Cr(2)O(3) based materials were also insoluble at the studied pH values. On the other hand, the estimated IEP values deviated radically from the reported PZC values of similar materials.     

Microwave-Assisted Synthesis,Characterization and Modeling of CPO-27-Mg Metal-Organic Framework for Drug Delivery

The coordination polymer CPO-27-Mg was rapidly synthesized under microwave irradiation. This material exhibits a sufficiently high drug loading towards aspirin (~8% wt.) and paracetamol (~14% wt.). The binding of these two molecules with the inner surface of the metal-organic framework was studied employing the Gaussian and Plane Wave approach of the Density Functional Theory. The structure of CPO-27-Mg persists after the adsorption of aspirin or paracetamol and their desorption energies, being quite high, decrease under solvent conditions.     

Towards analytical model optimization in atmospheric tomography

Modern ground‐based telescopes rely on a technology called adaptive optics in order to compensate for the loss of angular resolution caused by atmospheric turbulence. Next‐generation adaptive optics systems designed for a wide field of view require a stable and high‐resolution reconstruction of the turbulent atmosphere. By introducing a novel Bayesian method, we address the problem via reconstructing the atmospheric turbulence strength profile and the turbulent layers simultaneously, where we only use wavefront measurements of incoming light from guide stars. Most importantly, we demonstrate how this method can be used for model optimization as well. We propose two different algorithms for solving the maximum a posteriori estimate: the first approach is based on alternating minimization and has the advantage of integrability into existing atmospheric tomography methods. In the second approach, we formulate a convex non‐differentiable optimization problem, which is solved by an iterative thresholding method. This approach clearly illustrates the underlying sparsity‐enforcing mechanism for the strength profile. By introducing a tuning/regularization parameter, an automated model reduction of the layer structure of the atmosphere is achieved. Using numerical simulations, we demonstrate the performance of our method in practice. Copyright © 2016 John Wiley & Sons, Ltd.