Shell model of turbulence perturbed by L��vy noise

In this work we prove the existence and uniqueness of the strong solution of the shell model of turbulence perturbed by Lévy noise. The local monotonicity arguments have been exploited in the proofs.     

Mono and dinuclear complexes of half-sandwich platinum group metals (Ru, Rh and Ir) bearing a flexible pyridyl-thiazole multidentate donor ligand

The mononuclear cationic complexes [(η⁶-C₆H₆)RuCl(L)]⁺ (1), [(η⁶-p-ⁱPrC₆H₄Me)RuCl(L)]⁺ (2), [(η⁵-C₅H₅)Ru(PPh₃)(L)]⁺ (3), [(η⁵-C₅Me₅)Ru(PPh₃)(L)]⁺ (4), [(η⁵-C₅Me₅)RhCl(L)]⁺ (5), [(η⁵-C₅Me₅)IrCl(L)]⁺ (6) as well as the dinuclear dicationic complexes [{(η⁶-C₆H₆)RuCl}₂(L)]²⁺ (7), [{(η⁶-p-ⁱPrC₆H₄Me)RuCl}₂(L)]²⁺ (8), [{(η⁵-C₅H₅)Ru(PPh₃)}2(L)]²⁺ (9), [{(η⁵-C₅Me₅)Ru(PPh₃)}₂(L)]²⁺ (10), [{(η⁵-C₅Me₅)RhCl}₂(L)]²⁺ (11) and [{(η⁵-C₅Me₅)IrCl}₂(L)]²⁺ (12) have been synthesized from 4,4′-bis(2-pyridyl-4-thiazole) (L) and the corresponding complexes [(η⁶-C₆H₆)Ru(μ-Cl)Cl]₂, [(η⁶-p-ⁱPrC₆H₄Me)Ru(μ-Cl)Cl]₂, [(η⁵-C₅H₅)Ru(PPh₃)₂Cl)], [(η⁵-C₅Me₅)Ru(PPh₃)₂Cl], [(η⁵-C₅Me₅)Rh(μ-Cl)Cl]₂ and [(η⁵-C₅Me₅)Ir(μ-Cl)Cl]₂, respectively. All complexes were isolated as hexafluorophosphate salts and characterized by IR, NMR, mass spectrometry and UV-vis spectroscopy. The X-ray crystal structure analyses of [3]PF₆, [5]PF₆, [8](PF₆)₂ and [12](PF₆)₂ reveal a typical piano-stool geometry around the metal centers with a five-membered metallo-cycle in which 4,4′-bis(2-pyridyl-4-thiazole) acts as a N,N′-chelating ligand.     

Thermally stimulated current and differential scanning calorimetry spectroscopy for the study of polymer nanocomposites

The thermally stimulated discharge current (TSC) and differential scanning calorimetry (DSC) spectroscopy have been recorded in 25 μm thick samples of pristine polycarbonate (PC) and zinc oxide nano particle-filled polycarbonate. Polycarbonate (PC)/zinc oxide (ZnO) nanocomposites of different mass ratio (e.g., 1, 3, and 5%) were prepared by sol–gel method, followed by film casting. The glass transition temperature of nanocomposite samples increases with increase in concentration of ZnO nano fillers. It is due to the strong interaction between inorganic and organic components. The TSC peaks of nanocomposite and pristine PC indicate the multiple relaxation process. It has been observed that the magnitude of TSC decreases with increase in concentration of nanofillers. The TSC characteristics of 5% filled nanocomposites shows exponential increase of current at higher temperature region. This increase in current is caused by formation of charge-transfer complex between inorganic phase (e.g., ZnO) and organic phase (e.g., PC). Thus, the nano material like zinc oxide transfers the charge carriers from inorganic phase to organic phase rapidly and resultant current increases exponentially. This current is known as leakage current or breakdown current. TSC peak height is observed as a function of the polarizing field. The height of TSC peak increases as the field increases in pristine PC, while TSC peak height is suppressed in nanocomposite samples. This indicates the amount of space charge is smaller in the nanocomposites with a proper addition of ZnO nano fillers than in the pristine PC.     

Comparison of aromatic NH···π, OH···π, and CH···π interactions of alanine using MP2, CCSD, and DFT methods

A comparison of the performance of various density functional methods including long‐range corrected and dispersion corrected methods [MPW1PW91, B3LYP, B3PW91, B97‐D, B1B95, MPWB1K, M06‐2X, SVWN5, ωB97XD, long‐range correction (LC)‐ωPBE, and CAM‐B3LYP using 6‐31+G(d,p) basis set] in the study of CH···π, OH···π, and NH···π interactions were done using weak complexes of neutral (A) and cationic (A⁺) forms of alanine with benzene by taking the Møller–Plesset (MP2)/6‐31+G(d,p) results as the reference. Further, the binding energies of the neutral alanine–benzene complexes were assessed at coupled cluster (CCSD)/6‐31G(d,p) method. Analysis of the molecular geometries and interaction energies at density functional theory (DFT), MP2, CCSD methods and CCSD(T) single point level reveal that MP2 is the best overall performer for noncovalent interactions giving accuracy close to CCSD method. MPWB1K fared better in interaction energy calculations than other DFT methods. In the case of M06‐2X, SVWN5, and the dispersion corrected B97‐D, the interaction energies are significantly overrated for neutral systems compared to other methods. However, for cationic systems, B97‐D yields structures and interaction energies similar to MP2 and MPWB1K methods. Among the long‐range corrected methods, LC‐ωPBE and CAM‐B3LYP methods show close agreement with MP2 values while ωB97XD energies are notably higher than MP2 values. © 2010 Wiley Periodicals, Inc. J Comput Chem 2010     

Comparison of single and sequential extraction procedures for the study of rare earth elements remobilisation in different types of soils

With the continual increase in the utilisation of rare earth elements (REE) for industrial and agricultural purposes, research into the environmental and biogeochemical behaviour of REE had attracted much interest in recent times. This study principally describes the distribution of REE in four different types of soils like lateritic soil (S-1), in situ natural soil (S-2), soil contaminated by mining activity (S-3) and accidentally polluted soil (S-4) utilizing the optimised BCR sequential extraction procedure and partial extractions with various types of single extractants such as unbuffered salt solutions 0.1 M NaNO₃, 0.01 M CaCl₂, 1 M NH₄NO₃; complexing agents 0.005 M DTPA and 0.05 M EDTA; acid solutions 0.43 M CH₃COOH and 1 M HCl. Comparison of the sum of the four BCR fractions, which included an aqua regia attack on the residue, with the pseudo-total aqua regia digest values to assess the accuracy of the BCR partioning approach has been undertaken. Partial extraction results with several single extractants have also been reported for all the REE elements including yttrium which have been analysed by the optimised BCR procedure. Results obtained after 24 h extraction with each of the single extractant have also been discussed. The extraction with 1 M HCl during 24 h yielded similar quantities of REE as those released under the combined steps of 1, 2 and 3 of the BCR sequential extraction for all the four different type of soil samples indicating that this reagent can be used successfully to estimate the total extractable contents of REE in various types of soil samples.     

Kinetics and mechanism of the ligand substitution reaction between aquapentacyanoruthenate(II) and 4-cyanopyridine in the presence of anionic surfactant micelles

The kinetics of ligand substitution between aquapentacyanoruthenate(II) ion, [Ru(CN)₅H₂O]³⁻ and 4-cyanopyridine (4-CNpy) has been investigated spectrophotometrically in the presence of anionic surfactant micelle, namely sodium dodecylsulphate (SDS) at 400 nm (λ_max of the intense yellow product [Ru(CN)₅4-CNpy]³⁻) under pseudo-first-order conditions using at least 10% excess of 4-CNpy over [Ru(CN)₅H₂O]³⁻. The reaction was studied as a function of [Ru(CN)₅H₂O³⁻], [4-CNpy], [SDS], pH, ionic strength and temperature, by varying each of these variables one at a time. The reaction exhibited overall second-order kinetics, being first order each in [4-CNpy] and [Ru(CN)₅H₂O³⁻] over a wide concentration range. Variation of ionic strength of the medium had a significant negative effect on the rate. The SDS micelle, being negatively charged, does not reveal any regular effect except at or near its critical micelle concentration (c.m.c). The rate of reaction was measured at different temperatures, and the activation parameters were computed using Arrhenius and Eyring plots. A plausible mechanism consistent with the experimental results has been proposed.     

Simulation of FTTH at 10 Gbit/s for 8 OTU by GE-PON Architecture

In this paper a fiber communication system is employed using Giga Ethernet Passive Optical Network (GE-PON) architecture. In this architecture an optical fiber is employed directly from a Central Office to the home. A 1:8 splitter is used as a PON element which establishes communication between a Central Office to different users. In this paper GE-PON architecture has investigated for different lengths from a Central Office to the PON in the terms of BER. For 10 Gbit/s system the plots between the BER and transmission distance is plotted and it is seen that as the distance increases beyond the 15 km the BER is increased very sharply. Results in the form of Voice and Data spectrum for different users of FTTH with GE-PON architecture are shown.     

Performance analysis of metro WDM network based on an optical cross connects and arrayed waveguide grating demultiplexer

In this paper, we have demonstrated the quality-of-service offered by the metropolitan area network which is based on optical cross connect (OXC) and arrayed waveguide grating (AWG) demultiplexer operating at 10 Gb/s with 0.1 nm channel spacing for NRZ signal transmission. The data is successfully transmitted to a distance of 40 km with a reasonably good BER of 2.388 × 10⁻³⁵. The OXC and AWG demultiplexers in the proposed architecture allow incremental expansion in terms of the number of wavelength channels to be transmitted. Dispersion and crosstalk are the main signal-degrading factors arising from the operation of the OXC and the effectiveness of each factor is individually investigated.     

Antibacterial,SOD mimic and nuclease activities of copper(II) complexes containing ofloxacin and neutral bidentate ligands

Drug‐based mixed‐ligand copper(II) complexes of type [Cu(OFL)(Aⁿ)Cl]·5H₂O (OFL = ofloxacin, A¹ = pyridine‐2‐carbaldehyde, A² = 2,2′‐bipyridylamine, A³ = thiophene‐2‐carbaldehyde, A⁴ = 2,9‐dimethyl‐1,10‐phenanthroline, A⁵ = 2,9‐dimethyl‐4,7‐diphenyl‐1,10‐phenanthroline, A⁶ = 4,5‐diazafluoren‐9‐one, A⁷ = 1,10‐phenanthroline‐5,6‐dione and A⁸ = 5‐nitro‐1,10‐phenanthroline) were synthesized and characterized. Spectral investigations of complexes revealed square pyramidal geometry. Viscosity measurement and absorption titration were employed to determine the mode of binding of complexes with DNA. DNA cleavage study showed better cleaving ability of the complexes compared with metal salt and standard drug by conversion of a supercoiled form of pUC19 DNA to linear via circular. From the SOD mimic study, concentration of complexes ranging from 0.415 to 1.305 µM is enough to inhibit the reduction rate of NBT by 50% (IC₅₀) in the NADH‐PMS system. Antibacterial activity was assayed against selective Gram‐negative and Gram‐positive microorganisms using the doubling dilution technique. Copyright © 2010 John Wiley & Sons, Ltd.