Utjecaj negativnih iona na ionsko-zvučne solitarne valove u plazmi s dvije temperature elektrona

Ion-acoustic solitary waves in a drift negative ion plasma have been investigated for two-electron temperatures. Tagare and Reddy studied the effect of higher-order nonlinearity on ion-acoustic waves with cold positive and negative ions for isothermal and non-isothermal electrons using reductive perturbation technique. In this work, we study warm positive and negative ions with two-temperature isothermal electrons using the pseudopotential method. It is found that the concentration of negative ions, drift velocities, mass ratios, equal temperatures of ions (particular case) and presence of two groups of electrons and their ratios modify the profiles of the Sagdeev pseudopotential curves of the solitary waves in the plasma of the first- (φ1) and second-order (φ2) solitary-wave solutions.Istražujemo ionsko-zvučne solitarne valove u protječnoj negativnoj plazmi s dvije temperature elektrona. Tagare i Reddy su proučavali učinak nelinearnosti višeg reda na ionsko-zvučne valove s hladnim pozitivnim i negativnim ionima primjenom reduktivne metode smetnje. U ovom se radu proučavaju vrući pozitivni i negativni ioni metodom pseudopotencijala. Nalazimo da koncentracija negativnih iona, brzine protjecanja, omjeri masa, poseban slučaj jednakih temperatura iona i prisutnost dvije grupe elektrona i njihov omjer mijenjaju profile krivulja Sagdeevog pseudopotencijala solitarnih valova u plazmi za rješenja prvog (φ1) i drugog (φ2) reda

Utjecaj negativnih iona na ionsko-zvučne solitarne valove u plazmi s dvije temperature elektrona

Ion-acoustic solitary waves in a drift negative ion plasma have been investigated for two-electron temperatures. Tagare and Reddy studied the effect of higher-order nonlinearity on ion-acoustic waves with cold positive and negative ions for isothermal and non-isothermal electrons using reductive perturbation technique. In this work, we study warm positive and negative ions with two-temperature isothermal electrons using the pseudopotential method. It is found that the concentration of negative ions, drift velocities, mass ratios, equal temperatures of ions (particular case) and presence of two groups of electrons and their ratios modify the profiles of the Sagdeev pseudopotential curves of the solitary waves in the plasma of the first- (φ1) and second-order (φ2) solitary-wave solutions.Istražujemo ionsko-zvučne solitarne valove u protječnoj negativnoj plazmi s dvije temperature elektrona. Tagare i Reddy su proučavali učinak nelinearnosti višeg reda na ionsko-zvučne valove s hladnim pozitivnim i negativnim ionima primjenom reduktivne metode smetnje. U ovom se radu proučavaju vrući pozitivni i negativni ioni metodom pseudopotencijala. Nalazimo da koncentracija negativnih iona, brzine protjecanja, omjeri masa, poseban slučaj jednakih temperatura iona i prisutnost dvije grupe elektrona i njihov omjer mijenjaju profile krivulja Sagdeevog pseudopotencijala solitarnih valova u plazmi za rješenja prvog (φ1) i drugog (φ2) reda

Study of Thermo-Sensitive In-Situ Gels for Ocular Delivery

The aim of the present study was the development of thermo-sensitive in-situ gels for in-vitro evaluation of ophthalmic delivery systems of ketorolac tromethamine (KT), based on methylcellulose (MC) in combination with hydroxypropylmethyl cellulose (HPMC). The gel temperature of 1% MC solution was observed at 60°C. It was found that 6% oral rehydration salt without dextrose (ORS) was capable to reduce the gel temperature below physiological temperature. HPMC was added to increase viscosity and drug release time. The results indicated a large increase in viscosity at 37°C with addition of HPMC whch provided sustained release of the drug over a 4h period. From in-vitro release studies, it could be concluded that the developed systems were thus a better alternative to conventional eye drops

High temperature creep of tungsten free cobalt based Superalloys

The current study reports the high temperature creep behaviour of the recently discovered1,2,3 Co-Al-Mo-Nb/Ta superalloys with additions of Ni, Cr and Ti. These alloys have a classical microstructure, where the L12 ordered is present uniformly throughout the matrix of cobalt in the form of coherent precipitates. The in these alloys, has been stabilized without the addition of tungsten. This results in lower density as well as easier homogenization treatment, since slowly diffusing tungsten is absent. The solvus of these alloys is beyond 1000o C. The alloys exhibit excellent mechanical properties at higher temperatures, with specific strengths that are attractive compared to commercially available current cast polycrystalline cobalt based superalloys. Please click Additional Files below to see the full abstract

Butea monosperma bark extract mediated green synthesis of silver nanoparticles: Characterization and biomedical applications

AbstractThe work deals with an environmentally benign process for the synthesis of silver nanoparticle using Butea monosperma bark extract which is used both as a reducing as well as capping agent at room temperature. The reaction mixture turned brownish yellow after about 24h and an intense surface plasmon resonance (SPR) band at around 424nm clearly indicates the formation of silver nanoparticles. Fourier transform-Infrared (FT-IR) spectroscopy showed that the nanoparticles were capped with compounds present in the plant extract. Formation of crystalline fcc silver nanoparticles is analysed by XRD data and the SAED pattern obtained also confirms the crystalline behaviour of the Ag nanoparticles. The size and morphology of these nanoparticles were studied using High Resolution Transmission Electron Microscopy (HRTEM) which showed that the nanoparticles had an average dimension of ∼35nm. A larger DLS data of ∼98nm shows the presence of the stabilizer on the nanoparticles surface. The bio-synthesized silver nanoparticles revealed potent antibacterial activity against human bacteria of both Gram types. In addition these biologically synthesized nanoparticles also proved to exhibit excellent cytotoxic effect on human myeloid leukemia cell line, KG-1A with IC50 value of 11.47μg/mL

Garcinol loaded vitamin E TPGS emulsified PLGA nanoparticles: preparation, physicochemical characterization, in vitro and in vivo studies

Garcinol (GAR) is a naturally occurring polyisoprenylated phenolic compound. It has been recently investigated for its biological activities such as antioxidant, anti-inflammatory, anti ulcer, and antiproliferative effect on a wide range of human cancer cell lines. Though the outcomes are very promising, its extreme insolubility in water remains the main obstacle for its clinical application. Herein we report the formulation of GAR entrapped PLGA nanoparticles by nanoprecipitation method using vitamin E TPGS as an emulsifier. The nanoparticles were characterized for size, surface morphology, surface charge, encapsulation efficiency and in vitro drug release kinetics. The MTT assay depicted a high amount of cytotoxicity of GAR-NPs in B16F10, HepG2 and KB cells. A considerable amount of cell apoptosis was observed in B16f10 and KB cell lines. In vivo cellular uptake of fluorescent NPs on B16F10 cells was also investigated. Finally the GAR loaded NPs were radiolabeled with technetium-99m with >95% labeling efficiency and administered to B16F10 melanoma tumor bearing mice to investigate the in vivo deposition at the tumor site by biodistribution and scintigraphic imaging study. In vitro cellular uptake studies and biological evaluation confirm the efficacy of the formulation for cancer treatmen

Prompt emission polarimetry of Gamma Ray Bursts with ASTROSAT CZT-Imager

X-ray and Gamma-ray polarization measurements of the prompt emission of Gamma-ray bursts (GRBs) are believed to be extremely important for testing various models of GRBs. So far, the available measurements of hard X-ray polarization of GRB prompt emission have not significantly constrained the GRB models, particularly because of the difficulty of measuring polarization in these bands. The CZT Imager (CZTI) onboard {\em AstroSat} is primarily an X-ray spectroscopic instrument that also works as a wide angle GRB monitor due to the transparency of its support structure above 100 keV. It also has experimentally verified polarization measurement capability in the 100 $-$ 300 keV energy range and thus provides a unique opportunity to attempt spectro-polarimetric studies of GRBs. Here we present the polarization data for the brightest 11 GRBs detected by CZTI during its first year of operation. Among these, 5 GRBs show polarization signatures with $\gtrapprox$3$\sigma$, and 1 GRB shows $\>$2$\sigma$ detection significance. We place upper limits for the remaining 5 GRBs. We provide details of the various tests performed to validate our polarization measurements. While it is difficult yet to discriminate between various emission models with the current sample alone, the large number of polarization measurements CZTI expects to gather in its minimum lifetime of five years should help to significantly improve our understanding of the prompt emission.Comment: Accepted for Publication in ApJ ; a figure has been update

AstroSat-CZTI detection of variable prompt emission polarization in GRB 171010A

We present spectro-polarimetric analysis of \thisgrb\ using data from \asat, \fermi, and \swift, to provide insights into the physical mechanisms of the prompt radiation and the jet geometry. Prompt emission from \thisgrb\ was very bright (fluence $>10^{-4}$~ergs~cm$^{-2}$) and had a complex structure composed of the superimposition of several pulses. The energy spectra deviate from the typical Band function to show a low energy peak $\sim 15$~keV --- which we interpret as a power-law with two breaks, with a synchrotron origin. Alternately, the prompt spectra can also be interpreted as Comptonized emission, or a blackbody combined with a Band function. Time-resolved analysis confirms the presence of the low energy component, while the peak energy is found to be confined in the range of 100--200~keV. Afterglow emission detected by \fermi-LAT is typical of an external shock model, and we constrain the initial Lorentz factor using the peak time of the emission. \swift-XRT measurements of the afterglow show an indication for a jet break, allowing us to constrain the jet opening angle to $>$ 6\degr. Detection of a large number of Compton scattered events by \asat-CZTI provides an opportunity to study hard X-ray polarization of the prompt emission. We find that the burst has high, time-variable polarization, with the emission {\bf have higher polarization} at energies above the peak energy. We discuss all observations in the context of GRB models and polarization arising due to {\bf due to physical or geometric effects:} synchrotron emission from multiple shocks with ordered or random magnetic fields, Poynting flux dominated jet undergoing abrupt magnetic dissipation, sub-photospheric dissipation, a jet consisting of fragmented fireballs, and the Comptonization model.Comment: Accepted for publication in Ap