Synthesis,pyrolytic and bioassay studies of complexes Ni(II), Cu(II) and Zn(II) bromides with a chelating ligand of N,N donor sites

Coordination complexes of modified hydrazine are prepared with Ni(II), Cu(II), and Zn(II) metal ions. The ligand is synthesized by removing the methoxy moiety of methyl anthranilate with nitrogen of hydrazine hydrate, creating new coordination site. The coordination complexes are synthesized by reacting the ABH ligand with dehydrated M(II) [Cu²⁺, Zn²⁺ and Ni²⁺] bromide in an inert environment. The structures of the coordination complexes are elucidated basing on the physical measurements including elemental analysis, NMR, IR, UV–Vis spectra, magnetic and conductance measurements. These results reflect the M(ABH)Br₂ composition of the corresponding complexes. Thermal studies show the Irving William trend for the stability of complexes. Antibacterial activities and antifungal studies are also carried out in order to investigate the biological activity upon complexation.     

Thermogravimetric, differential scanning calorimetric and experimental thermal transport study of MWCNT/NBR nanocomposites

Pristine multiwalled carbon nanotubes (MWCNTs) were impregnated in acrylonitrile butadiene rubber (NBR) using internal dispersion kneader and two roller mixing mill to investigate the effects of various nanotubes concentrations on the thermal transport/stability of rubber nanocomposites. Thermal conductivity (λ _N) and thermal impedance (R) measurement experimental setups were established according to ASTM E1225-99 and D5470-03. The 1 mass % addition of MWCNTs in the polymer matrix has enhanced R up to 44 % and reduced λ _N of the rubber nanocomposite up to 40 % compare to the base composite formulation. Thermal decomposition and differential thermal analyses of the fabricated composite specimens simulate that the thermal stability and endothermic capability are augmented with increasing the nanotubes contents in the host matrix. The progressive incorporations of carbon nanotubes into the rubber matrix have efficiently influenced the composite specimens regarding glass transition, crystallization, and melting temperatures including their specific enthalpies. Scanning electron microscopy along with the energy dispersive spectroscopy was used to analyze MWCNTs dispersion in NBR matrix, compositional analysis of the nanocomposite, and impregnated nanotubes.     

Weak linear bilevel programming problems: existence of solutions via a penalty method

We are concerned with a class of weak linear bilevel programs with nonunique lower level solutions. For such problems, we give via an exact penalty method an existence theorem of solutions. Then, we propose an algorithm.     

Exponential stabilization of a flexible structure with a local interior control and under the presence of a boundary infinite memory

In this paper, we deal with the interior stabilization problem of a flexible structure governed by a hyperbolic partial differential equation coupled to two ordinary differential equations. Contrary to the previous works on the system, the boundary control is subject to the presence of an infinite memory term. In order to deal with such a nonlocal term, the minimal state approach is invoked. Specifically, a localized interior control is proposed in order to compensate the infinite memory effect. Thereafter, reasonable assumptions on the memory kernel are evoked so that the closed-loop system is shown to be well-posed thanks to semigroups theory of linear operators. Furthermore, the resolvent method is used to establish the exponential stability of the system.     

Laser irradiation effects on the combination of levodopa and carbidopa in the presence and absence of magnetic field

Laser irradiation effects on the combination of levodopa and carbidopa in the presence and absence of magnetic field were studied. The structural and surface morphology of irradiated targets were measured by X-ray diffractometer (XRD) and scanning electron microscopy (SEM), respectively. Energy dispersive X-ray spectrometry (EDS) was used for chemical analysis. XRD analysis indicates increase in grain size for 2?min laser irradiation in the absence of magnetic field, but for 4 and 6?min it revealed decrease in grain size. While grain size decreased at 2 and 4?min exposures in the presence of magnetic field but grain size slightly increased with the increase of exposure time up to 6?min. Micro-nano-sized structures (including hydrodynamic sputtering, splashing and crater) were observed by SEM analysis. EDS displayed peaks for carbon (C) and oxygen (O), but peaks for hydrogen (H) and nitrogen (N) are missing. The present study will provide basis for the use of low-cost and environment-friendly diode laser to enhance the characteristics of this combination (levodopa?+?carbidopa).     

On exact Kerr-Schild type vacuum solutions to Salam's two-tensor theory of gravity

A Kerr-Schild type ansatz for thef andg tensor fields leads to a tractable form of the field equations of Salam's two-tensor theory of gravity in vacuo. While the general solution contains the Schwarzschild and Kerr metrics in the pure Einstein vacuum case, we can show in thef-g case that all non-trivial (fg) solutions are restricted to have the form of plane-fronted waves.Supported by Fonds zur Förd. d. wiss. Forsch. in Österr., Nr. 1255.     

On the fractional differential equations with uncertainty

This paper is based on the concept of fuzzy differential equations of fractional order introduced by Agarwal et al. [R.P. Agarwal, V. Lakshmikantham, J.J. Nieto, On the concept of solution for fractional differential equations with uncertainty, Nonlinear Anal. 72 (2010) 2859-2862]. Using this concept, we prove some results on the existence and uniqueness of solutions of fuzzy fractional differential equations.     

Nitric oxide delivery by core/shell superparamagnetic nanoparticle vehicles with enhanced biocompatibility

We report the synthesis of Fe(3)O(4)/silica core/shell nanoparticles and their functionalization with S-nitrosothiols. These nanoparticles are of immense interest because of their nitric oxide (NO) release capabilities in human alveolar epithelial cells. Moreover, they act as large storage reservoirs of NO that can be targeted magnetically to the specific site with a sustainable release of NO for up to 50 h. Such nanoparticles provide an enhancement of the biocompatibility with released NO while allowing intracellular accumulation ascribed to their small size.     

A value-adding approach to reliability under preventive maintenance costs and its applications

No equipment (system) can be perfectly reliable in spite of the utmost care and best efforts on the part of the designer, decision-maker and manufacturer. The two sides of maintenance are corrective and preventive maintenance. It is generally assumed that a preventive maintenance action is less costly than a repair maintenance action. We examine this proposition in detail on the basis of a failure-time model that relates conformance quality to reliability. Illustratively, we present reliability in the context of contracts with asymmetric information. The model shows how to overcome information rents through price distortions and quantity rationing. The paper ends with a conclusion and an outlook to future studies.