On the repetitive operation of a self-switched transversely excited atmosphere CO<Subscript>2</Subscript> laser

The repetition rate capability of self-switched transversely excited atmosphere (TEA) CO₂ laser was studied for different gas flow configurations. For an optimized gas flow configuration, repetitive operation was achieved at a much smaller gas replenishment factor between two successive pulses when compared with repetitive systems energized by conventional pulsers.     

Generalized Univex Functions in Nonsmooth Multiobjective Optimization

In this paper, we have considered a nonsmooth multiobjective optimization problem where the objective and constraint functions involved are directionally differentiable. A new class of generalized functions (d???ρ???η???θ)-type I univex is introduced which generalizes many earlier classes cited in literature. Based upon these generalized functions, we have derived weak, strong, converse and strict converse duality theorems for mixed type multiobjective dual program in order to relate the efficient and weak efficient solutions of primal and dual problem.     

Experimental and theoretical studies of Mn(II) and Co(II) metal complexes of a tridentate Schiff's base ligand and their biological activities

We have used the condensation method to synthesize 2-acetyl-5-methylsemicarbazone ligand. Manganese(II) and Cobalt(II) complexes having formula [ML₂]X₂ were synthesized where M = Mn(II) and Co(II), L = ligand, X = Cl⁻, CH₃COO⁻, NO₃⁻, ½SO₄²⁻. The characterization data suggests the octahedral geometry for all the synthesized complexes. Tridentate nature of the 2-acetyl-5-methylsemicarbazone ligand was revealed by IR studies. Molar conductance analysis suggested the electrolytic nature of the complexes. The theoretical study includes geometrical optimization, HOMO-LUMO energy gap, energetic parameters and dipole moment. These results also confirmed the tridentate nature of the ligand and the octahedral geometry of complexes. The molecular electrostatic potential (MEP) study suggested the reactive sites for an electrophilic or nucleophilic attack in the ligand. We tested the synthesized compounds for their antifungal and antibacterial action via well diffusion method and found that parent ligand after the coordination with the metal ion showed more effective inhibition against bacteria and fungi.     

Stress Degradation Behavior of Desipramine Hydrochloride and Development of Suitable Stability-Indicating LC Method

A simple reverse phase liquid chromatographic method was developed for the quantitative determination of desipramine hydrochloride and its related impurities in bulk drugs which is also stability-indicating. During the forced degradation at hydrolysis, oxidative, photolytic and thermal stressed conditions, the degradation results were only observed in the oxidative stress condition. The blend of the degradation product and potential impurities were used to optimize the method by an YMC Pack Pro C₁₈ stationary phase. The LC method employs a linear gradient elution with the water–acetonitrile–trifluoroacetic acid as mobile phase. The flow rate was 1.0 mL min^?1 and the detection wavelength 215 nm. The stressed samples were quantified against a qualified reference standard and the mass balance was found close to 99.0% (w/w) when the response of the degradant was considered to be equal to the analyte (i.e. desipramine). The developed RP-LC method was validated in agreement with ICH requirements.     

Experimental Investigations on Highly Conducting Solid Bio-Polymer Electrolytes Based on Latex of Calotropis gigantea Plant

The study has prepared highly conducting polymer electrolyte films using solution cast technique with poly(vinylidene fluoride-co-hexafluoropropylene) PVDF-HFP, mixture of ethylene carbonate (EC), and propylene carbonate (PC) as plasticizer and latex of Calotropis gigantea (CGL) as an ionic source. In this study, four films are prepared using PVDF-HFP:CGL in ratio 1:1 with the increasing concentration of EC+PC as 1, 2, 3, and 4 M named as 1:1:1, 1:1:2, 1:1:3, 1:1:4. The prepared polymer electrolyte is examined by polarized optical microscopy (POM), elemental dispersive X-ray technique (EDX), and complex impedance spectroscopy. EDX and POM are studied for the surface morphology of all prepared samples and to investigate the porous nature of films. The enhancement in ionic conductivity occurs due to CGL and increasing amount of EC-PC. Conductivity of highest composition (1:1:4) polymer electrolyte film is found to be ≈10⁻³ S cm⁻¹. The optimized polymer electrolyte film is considered as a promising candidate for application in supercapacitors.     

RP–LC Simultaneous Determination of Aconitine, Solanine and Piperine in an Ayurvedic Medicine

By optimizing the extraction, separation and analytical conditions, a reliable, rapid, simple and accurate liquid chromatography method with UV detection was developed for the simultaneous quantitative determination of aconitine, solanine and piperine in an ayurvedic preparation prepared from Aconitum ferox, Solanum indicum, Piper nigrum and Piper longum. The separation of these alkaloids was achieved on an reversed phase C-18 column (250 mm × 4.6 mm ID, 5 μm particle size), with isocratic elution using a mixture of acetonitrile–potassium hydrogen phosphate buffer (10 mM, pH 7.5)–methanol (60:25:15, v/v) at a flow rate of 1 mL min^?1 with UV detection at 227 nm for aconitine and solanine while 343 nm for piperine. The calibration curves were linear with correlation coefficients of 0.9990, 0.9942, 0.9989 for solanine, piperine and aconitine, respectively. The % Relative standard deviation (%RSD) values were less than 2% in the concentration range of 10–100 μg mL^?1 for all the three alkaloids. Intra-day assay and inter-day assay precision of the analytes were less than 2%, and the average recovery rates obtained were in the range of 98–102% for all with %RSD below 2%. Quantitative analysis of the alkaloids in the laboratory and marketed formulations showed that the contents of the alkaloids varied significantly. This method can provide a scientific and technical platform to the product manufacturers for setting up a quality control standard as well as to the public for quality and safety assurance of the proprietary ayurvedic formulations.     

An efficient stereoselective dihydroxylation of glycals using a bimetallic system, RuCl3/CeCl3/NaIO4

A catalytic dihydroxylation reaction on glycals has been developed using a bimetallic oxidizing system to furnish sugar 1,2-diols in a highly stereoselective manner.     

Designs of all-optical NOR gates using SOA based MZI

The paper investigates the non-linear behavior of semiconductor optical amplifier with Mach–Zehnder interferometer (SOA-MZI) configuration which makes it to work as a logic gate. The two designs of NOR gate based on SOA-MZI have been verified. The basic principal of both designs are same. The summation of data pulses have been taken and inverted to perform a NOR operation. In the design, the first 3 dB coupler creates a phase difference of π/2 in clock pulse and data pulse while passing through two interferometer arms. The clock and data pulses pass through SOA which attenuates the clock pulse wherever the data pulse is present. After passing through second 3 dB coupler a phase difference of π/2 is again created. Therefore, if the clock pulse is in the same phase will be added and if it is out of phase, will be canceled. The designs have been investigated at different bit-rates to achieve higher extinction ratio (ER), Q-factor and bit-error rate (BER) for different pump currents of SOA.     

Design and performance analysis in multiuser optical CDMA systems

The article presents comparative performance analysis of the proposed Optical CDMA system for 32 and 16 users with two dimensional codes. Numerical simulations have been done under interference significant environment, considering noise and dark current at data rates 2.5, 5, 7.5 and 10 Gbps over single mode fiber for transmission distance of more than 270 km. Results illustrate overall good performance, degraded with augment in bit rate and transmission distance, impervious with raise in number of simultaneous active users. Depicts significant performance improvement with inclusion of forward error correction RS (255,239), for low attenuation and chirp factor. It perceived, this is one of the efficient functional techniques for next generation broadband optical networks together with higher security owing to encoding and decoding, as it allow multiple users in the network to access the same fiber channel asynchronously.