The method of lines solution of discrete ordinates method for non-grey media

A radiation code based on method of lines (MOL) solution of discrete ordinates method (DOM) for radiative heat transfer in non-grey absorbing-emitting media was developed by incorporation of a gas spectral radiative property model, namely wide band correlated-k (WBCK) model, which is compatible with MOL solution of DOM. Predictive accuracy of the code was evaluated by applying it to 1-D parallel plate and 2-D axisymmetric cylindrical enclosure problems containing absorbing-emitting medium and benchmarking its predictions against line-by-line solutions available in the literature. Comparisons reveal that MOL solution of DOM with WBCK model produces accurate results for radiative heat fluxes and source terms and can be used with confidence in conjunction with computational fluid dynamics codes based on the same approach.     

Discontinuous Boundary Value Problems with Retarded Argument and Eigenparameter-Dependent Boundary Conditions

In this paper we study the asymptotic formulas for the eigenvalues and corresponding eigenfunctions of discontinuous boundary value problems with retarded argument and eigenparameter-dependent boundary conditions.     

Two-dimensional inverse quasilinear parabolic problem with periodic boundary condition

In this study, we consider a coefficient problem of a quasi-linear two-dimensional parabolic inverse problem with periodic boundary and integral over determination conditions. We prove the existence, uniqueness and continuously dependence upon the data of the solution by iteration method. Also, we consider numerical solution for this inverse problem by using linearization and the implicit finite-difference scheme.     

Randomized first order algorithms with applications to ℓ 1-minimization

In this paper we propose randomized first-order algorithms for solving bilinear saddle points problems. Our developments are motivated by the need for sublinear time algorithms to solve large-scale parametric bilinear saddle point problems where cheap online assessment of the solution quality is crucial. We present the theoretical efficiency estimates of our algorithms and discuss a number of applications, primarily to the problem of ? ₁ minimization arising in sparsity-oriented signal processing. We demonstrate, both theoretically and by numerical examples, that when seeking for medium-accuracy solutions of large-scale ? ₁ minimization problems, our randomized algorithms outperform significantly (and progressively as the sizes of the problem grow) the state-of-the art deterministic methods.     

Improved Sensing Performance of Amperometric Urea Biosensor by Using Platinum Nanoparticles

A novel Platinum nanoparticle (PtNPs) modified Poly(pyrrole-co-1-(2-Aminophenyl)pyrrole)/Urease film coated Au electrode was designed for amperometric detection of urea. PtNPs quantity, film density and pH were optimized and interference effect of some substances readily found in municipal wastewater and blood was investigated. The biosensor responded to urea with a measurement concentration range of 0.1 to 30 mM, a sensitivity of 31.8 μA mM⁻¹ cm⁻², a LOD of 7.58 μM, an accuracy of 104 % and a RSD% of only 0.82. It sensed the concentration of urea in the municipal sewage water with recovery of 97.6 % (n=3) and remained 78 % of its initial response at 28^th day. Results confirmed that PtNPs with strong conductivity improved the electron transfer ability of the working electrode.     

Ab initio and density functional computations of the vibrational spectrum, molecular geometry and some molecular properties of the antidepressant drug sertraline (Zoloft) hydrochloride

Sertraline hydrochloride is a highly potent and selective inhibitor of serotonin (5HT). It is a basic compound of pharmaceutical application for antidepressant treatment (brand name: Zoloft). Ab initio and density functional computations of the vibrational (IR) spectrum, the molecular geometry, the atomic charges and polarizabilities were carried out. The infrared spectrum of sertraline is recorded in the solid state. The observed IR wave numbers were analysed in light of the computed vibrational spectrum. On the basis of the comparison between calculated and experimental results and the comparison with related molecules, assignments of fundamental vibrational modes are examined. The X-ray geometry and experimental frequencies are compared with the results of our theoretical calculations.     

Verifiable conditions of <Emphasis Type="Italic">ℓ</Emphasis><Subscript>1</Subscript>-recovery for sparse signals with sign restrictions

We propose necessary and sufficient conditions for a sensing matrix to be “s-semigood” – to allow for exact ℓ ₁-recovery of sparse signals with at most s nonzero entries under sign restrictions on part of the entries. We express error bounds for imperfect ℓ ₁-recovery in terms of the characteristics underlying these conditions. These characteristics, although difficult to evaluate, lead to verifiable sufficient conditions for exact sparse ℓ ₁-recovery and thus efficiently computable upper bounds on those s for which a given sensing matrix is s-semigood. We examine the properties of proposed verifiable sufficient conditions, describe their limits of performance and provide numerical examples comparing them with other verifiable conditions from the literature.     

One-pot synthesis of gold nanoparticles using tetradentate porphyrins

In this study, the meso-tetra (p-hydroxyphenyl) porphyrin and meso-tetra (m-hydroxyphenyl) porphyrin were coated on to gold nanoparticles (AuNPs) via thioacetate anchors which easily dissociate to form S–Au bonds. 4-tert-butyl phenyl thioacetate-AuNPs were prepared and used as a monodentate passivant to control the size of the tetradentate porphyrin-AuNPs. The porphyrin-coated AuNPs were characterized by UV–Vis, TEM, XRD, and XPS analyses. The tetradentate porphyrin-AuNPs size is within a range of 5–15 nm in diameter with exotic shapes. The plausible network formation for AuNP@p-TPP-SAc and the capping structure of the AuNP@m-TPP-SAc have been suggested.     

Determination of lead separated selectively with ion exchange method from solution onto BCW in Sirnak, East Anatolia of Turkey

There are approximately 82 million of tons asphaltites reserves in ?irnak, East Anatolia of Turkey. The present study was investigated to employ ashes of S?rnak BCW (burned coal waste) as an ion exchange in removal of important toxic metal, Lead (Pb), in high yields by adsorption. The ion exchange characteristics of lead onto BCW from aqueous solution were investigated with respect to the changes in pH of solution, adsorbent dosage, initial metal ion concentration, contact time and temperature of solution. For the adsorption of lead, the Langmuir isotherm model fitted to equilibrium data better than the Freundlich isotherm model. Thermodynamic functions, the change of free energy (ΔG°), enthalpy (ΔH°) and entropy (ΔS°) of adsorption were also calculated for lead. These parameters showed that the adsorption was feasible, spontaneous and exothermic at 293–333 K. Experimental data were also evaluated in terms of kinetic characteristics of adsorption. The batch kinetic data were correlated to the pseudo-first order and pseudo-second order models. The data fitted better to the pseudo-second order equation. The activation energy of systems was determined. Experimental data have shown that BCW that was used in unmodified form; as low cost, readily available ion exchange; can be used for removal of lead from industrial waste waters. Analysis was determined using Flame Atomic Absorption Spectrometry (FAAS).     

Immobilization of laccase on polymer grafted polytetrafluoroethylene membranes for biosensor construction

In this study, Trametes versicolor laccase was immobilized on polytetrafluoroethylene (PTFE) membranes using two different techniques, entrapment to gelatin and covalent immobilization to the surface. For surface immobilization, functional groups were formed on PTFE surface by radiofrequency (RF) plasma treatment followed by polymer grafting. Two different polymers, polyacrylamide (pAAm) and polyacrylic acid (pAAc) were tried. For polyacrylamide grafted PTFE, a two-step polymerization process was used. The membranes were first treated with hydrogen plasma and pAAm grafted PTFE (pAAm-g-PTFE) was then formed by argon plasma treatment. To produce pAAc grafted PTFE (pAAc-g-PTFE), the surface was first treated with argon plasma and AAc was then attached to the surface by heat treatment (70 °C, 6 h). For both cases, an optimized carbodiimide coupling reaction was used for laccase immobilization. Enzyme activity was measured by an oxygen electrode using guaiacol as substrate. All three biosensing membranes were characterized and compared in terms of optimum working conditions, storage stability and reusability. Our study concluded that although a higher activity was obtained by gelatin entrapped laccase, its mechanical instability and poor storage life makes the gelatin biosensor unattractive for multiple usages and for field measurements. pAAc-g-PTFE biosensor was found to be more stable and highly reusable (ca. 50 times) when compared with the other two biosensors. In addition, its sensitivity was suitable for field applications. Therefore, the pAAc-g-PTFE biosensor could be proposed as an alternative on-site detection tool for phenolic compound monitoring.