Dielectric relaxation studies of acetonitrile/propylene glycol and their binary mixtures

Dielectric relaxation spectra in the frequency range 0.02 < ν/GHz < 20 have been collected for propylene glycol (PG), acetonitrile (AN) and their binary mixtures between 303 K-323 K. The average relaxation times have been calculated by the Cole-Davidson and Cole-Cole relaxation models. The experimental determined values of static dielectric permittivity (ε0), relaxation time (τ), excess permittivity (εE) and excess inverse relaxation time (1/τ)E show smooth temperature dependence. The larger relaxation time values of propylene glycol when compared to acetonitrile are due to the co-operative process of multimers with O-H-O linkage and also the steric hindrance behavior phenomena. The activation entropy (ΔS*), activation enthalpy (ΔH*), Kirkwood correlation factor (gf), Helmholtz energy (ΔFE) parameters have also been determined for propylene glycol and acetonitrile and the results have been correlated

Accretion Flow Dynamics During 1999 Outburst of XTE J1859+226 - Modeling of Broadband Spectra and Constraining the Source Mass

We examine the dynamical behavior of accretion flow around XTE J1859+226 during the 1999 outburst by analyzing the entire outburst data ($\sim$ 166 days) from RXTE Satellite. Towards this, we study the hysteresis behavior in the hardness intensity diagram (HID) based on the broadband ($3 - 150$ keV) spectral modeling, spectral signature of jet ejection and the evolution of Quasi-periodic Oscillation (QPO) frequencies using the two-component advective flow model around a black hole. We compute the flow parameters, namely Keplerian accretion rate (${\dot m}_d$), sub-Keplerian accretion rate (${\dot m}_h$), shock location ($r_s$) and black hole mass ($M_{bh}$) from the spectral modeling and study their evolution along the q-diagram. Subsequently, the kinetic jet power is computed as $L^{\rm obs}_{\rm jet}\sim 3 - 6 \times 10^{37}$ erg~s$^{-1}$ during one of the observed radio flares which indicates that jet power corresponds to $8-16\%$ mass outflow rate from the disc. This estimate of mass outflow rate is in close agreement with the change in total accretion rate ($\sim 14\%$) required for spectral modeling before and during the flare. Finally, we provide a mass estimate of the source XTE J1859+226 based on the spectral modeling that lies in the range of $5.2 - 7.9 M_{\odot}$ with 90\% confidence.Comment: 12 pages, 8 figures, 3 tables, Accepted for publication in Astrophysics and Space Scienc

Chlorfenapyr: a new insecticide with novel mode of action can control pyrethroid resistant malaria vectors

<p>Abstract</p> <p>Background</p> <p>Malaria vectors have acquired widespread resistance to many of the currently used insecticides, including synthetic pyrethroids. Hence, there is an urgent need to develop alternative insecticides for effective management of insecticide resistance in malaria vectors. In the present study, chlorfenapyr was evaluated against <it>Anopheles culicifacies </it>and <it>Anopheles stephensi </it>for its possible use in vector control.</p> <p>Methods</p> <p>Efficacy of chlorfenapyr against <it>An. culicifacies </it>and <it>An. stephensi </it>was assessed using adult bioassay tests. In the laboratory, determination of diagnostic dose, assessment of residual activity on different substrates, cross-resistance pattern with different insecticides and potentiation studies using piperonyl butoxide were undertaken by following standard procedures. Potential cross-resistance patterns were assessed on field populations of <it>An. culicifacies</it>.</p> <p>Results</p> <p>A dose of 5.0% chlorfenapyr was determined as the diagnostic concentration for assessing susceptibility applying the WHO tube test method in anopheline mosquitoes with 2 h exposure and 48 h holding period. The DDT-resistant/malathion-deltamethrin-susceptible strain of <it>An. culicifacies </it>species C showed higher LD50 and LD99 (0.67 and 2.39% respectively) values than the DDT-malathion-deltamethrin susceptible <it>An. culicifacies </it>species A (0.41 and 2.0% respectively) and <it>An. stephensi </it>strains (0.43 and 2.13% respectively) and there was no statistically significant difference in mortalities among the three mosquito species tested (p > 0.05). Residual activity of chlorfenapyr a.i. of 400 mg/m²on five fabricated substrates, namely wood, mud, mud+lime, cement and cement + distemper was found to be effective up to 24 weeks against <it>An. culicifacies </it>and up to 34 weeks against <it>An. stephensi</it>. No cross-resistance to DDT, malathion, bendiocarb and deltamethrin was observed with chlorfenapyr in laboratory-reared strains of <it>An. stephensi </it>and field-caught <it>An. culicifacies. </it>Potentiation studies demonstrated the antagonistic effect of PBO.</p> <p>Conclusion</p> <p>Laboratory studies with susceptible and resistant strains of <it>An. culicifacies </it>and <it>An. stephensi</it>, coupled with limited field studies with multiple insecticide-resistant <it>An. culicifacies </it>have shown that chlorfenapyr can be a suitable insecticide for malaria vector control, in multiple-insecticide-resistant mosquitoes especially in areas with pyrethroid resistant mosquitoes.</p

Triplet-state E.P.R. studies of exchange coupled copper(II) and silver(II) pairs in zinc(II) bis[N.N.-diisopropyldithiocarbamate]

Ambient temperature single crystal triplet-state E.P.R. studies on exchange coupled Cu2+-Cu2+ pairs in zinc(II) bis[N,N-diisopropyldithiocarbamate] matrix and temperature dependent E.P.R. studies on powder samples of Cu2+-Cu2+ and Ag2+-Ag2+ pairs, separated by a distance of 3·545 Å, in the same host lattice are reported. In addition to the doublet spectra, we observed the triplet lines arising due to spin-spin interactions. The directions of g and D-tensors in Cu2+-Cu2+ pairs vary by 42° in the xz-plane. The D-tensor seems to receive its contribution both from the dipolar and pseudo-dipolar interactions. The zero-field splitting (Z.F.S.) tensor, ‘D’, increases linearly with decrease in temperature down to 80K. This effect is seen in both Cu2+-Cu2+ and Ag2+-Ag2+ pairs: it is tentatively attributed to a crystal contraction at low temperatures. The integrated intensities of ΔM s = ±2 E.P.R. transitions of the triplets have been used to estimate the magnitude and sign of isotropic exchange coupling constants (2J). The values of 2J for Cu2+-Cu2+ and Ag2+-Ag2+ pairs are found to be 40·2 cm-1 and 62·5 cm-1, respectively. The interaction in both the systems has been found to be ‘ferromagnetic’

Crystal and molecular structure of dimeric bis[N,N-di-n-propyldithiocarbamato]zinc(II) and the study of exchange-coupled copper(II)-copper(II) pairs in its lattice

This article does not have an abstract

Ridge split and implant placement in deficient alveolar ridge: Case report and an update

Dr. Hilt Tatum 1970s introduced a method of ridge splitting or bone spreading, which over a period have been used in implant dentistry for esthetic rehabilitation and implant site preparation in cases of deficient alveolar ridges to satisfy the basic ideal need of hard tissue augmentation for functional and esthetic outcome of implant. In this case report, we describe a case of horizontal ridge augmentation using ridge split and simultaneous implant placement in esthetic maxillary premolar zone

Erratum to "Crystal and molecular structure of dimeric bis[N,N-di-n-propyldithiocarbamato]zinc(II) and the study of exchange-coupled copper(II)-copper(II) pairs in its lattice"

This article does not have an abstract

Optimization of process parameters of the activated tungsten inert gas welding for aspect ratio of UNS S32205 duplex stainless steel welds

The activated TIG (ATIG) welding process mainly focuses on increasing the depth of penetration and the reduction in the width of weld bead has not been paid much attention. The shape of a weld in terms of its width-to-depth ratio known as aspect ratio has a marked influence on its solidification cracking tendency. The major influencing ATIG welding parameters, such as electrode gap, travel speed, current and voltage, that aid in controlling the aspect ratio of DSS joints, must be optimized to obtain desirable aspect ratio for DSS joints. Hence in this study, the above parameters of ATIG welding for aspect ratio of ASTM/UNS S32205 DSS welds are optimized by using Taguchi orthogonal array (OA) experimental design and other statistical tools such as Analysis of Variance (ANOVA) and Pooled ANOVA techniques. The optimum process parameters are found to be 1 mm electrode gap, 130 mm/min travel speed, 140 A current and 12 V voltage. The aspect ratio and the ferrite content for the DSS joints fabricated using the optimized ATIG parameters are found to be well within the acceptable range and there is no macroscopically evident solidification cracking