Electrochemical behavior of austenitic AISI 304 stainless steel in two different solutions is presented here. Effect of cold rolling conditions on corrosion behavior of the steel is studied with ...respect to strain-induced α′-martensite phase, residual stress, and texture of both the austenite and α′-martensite phases. The annealed steel plate has been unidirectionally cold, rolled-up to 90% reductions. X-ray diffraction (XRD) technique has been employed to quantify the volume fractions of austenite and martensite phases and to study the textural development in the steel in rolled conditions. The presence of close pack crystallographic planes parallel to the specimen surface found to improve the corrosion properties.
ABSTRACT
We study accretion disc–corona connection in Seyfert 1 galaxies using simultaneous UV/X-ray observations of NGC 4593 (2016 July 14–18) and NGC 7469 (2017 October 15–19) performed with ...AstroSat. We use the X-ray (0.5–7.0 keV) data acquired with the Soft X-ray Telescope (SXT) and the UV (FUV: 130–180 nm, NUV: 200–300 nm) data obtained with the Ultra-Violet Imaging Telescope (UVIT). We also use the contemporaneous Swift observations of NGC 4593 and demonstrate AstroSat’s capability for X-ray/UV correlation studies. We performed UV/X-ray cross-correlation analysis using the interpolated and the discrete cross-correlation functions and found similar results. In the case of NGC 4593, we found that the variations in the X-rays lead to those in the FUV and NUV bands by ∼38 ks and ∼44 ks, respectively. These UV lags favour the disc-reprocessing model; they are consistent with the previous results within uncertainties. In contrast, we found an opposite trend in NGC 7469 where the soft X-ray variations lag those in the FUV and NUV bands by ∼41 ks and ∼49 ks, respectively. The hard lags in NGC 7469 favour the thermal Comptonization model. Our results may provide direct observational evidence for the variable intrinsic UV emission from the accretion disk, which acts as the seed for thermal Comptonization in a hot corona in a lamp-post-like geometry. The non-detection of disk reverberation photons in NGC 7469, using AstroSat data, is most likely due to a high accretion rate resulting in a hot accretion disc and large intrinsic emission.
Identification of the transmitted/founder virus makes possible, for the first time, a genome-wide analysis of host immune responses against the infecting HIV-1 proteome. A complete dissection was ...made of the primary HIV-1-specific T cell response induced in three acutely infected patients. Cellular assays, together with new algorithms which identify sites of positive selection in the virus genome, showed that primary HIV-1-specific T cells rapidly select escape mutations concurrent with falling virus load in acute infection. Kinetic analysis and mathematical modeling of virus immune escape showed that the contribution of CD8 T cell-mediated killing of productively infected cells was earlier and much greater than previously recognized and that it contributed to the initial decline of plasma virus in acute infection. After virus escape, these first T cell responses often rapidly waned, leaving or being succeeded by T cell responses to epitopes which escaped more slowly or were invariant. These latter responses are likely to be important in maintaining the already established virus set point. In addition to mutations selected by T cells, there were other selected regions that accrued mutations more gradually but were not associated with a T cell response. These included clusters of mutations in envelope that were targeted by NAbs, a few isolated sites that reverted to the consensus sequence, and bystander mutations in linkage with T cell-driven escape.
The working of gaseous ionization detectors can be broadly broken into few major steps: generation of primaries, their transport and amplification due to applied electromagnetic field, and, finally, ...induction of signal on pick-up electrodes due to movement of electrons and ions. Proper design and optimum utilization of such detectors require thorough understanding of each of these steps. Since they possess significant complexity, numerical modelling turns out to be an important tool to explore the dynamics and response of these detectors. There are several possible approaches that may be adopted to carry out detailed and realistic numerical simulation of gaseous detectors. Among these, the Monte-Carlo particle approach adopted by the Garfield++ toolkit is among the most prominent possibilities. Recently, a deterministic hydrodynamic approach has also turned out to be useful for this purpose. The steps necessary to create mathematical and numerical models of a gaseous detector is presented here, utilizing both particle and hydrodynamic approaches. Simple examples are used to illustrate the advantages and disadvantages of both the approaches.
Identification followed by directionality measurement using reconstruction of tracks is very crucial for studying the reaction vertex kinematics. In the field of low-energy nuclear physics, ...Active-Target Time Projection Chambers (AT-TPCs) can be used to study the nuclear reaction kinematics through tracking of the reaction products which is important for cross-section measurement. Ions produced in primary ionization by any charged particle along their track in the active gas volume of TPC can be utilized for track reconstruction with position-sensitive electron collection system placed inside an electric field. The TPC gas volume acts as the tracker of the reaction products and the target for the reaction with the incoming projectile simultaneously which is advantageous to conventional detector arrays. In this context, the design of the electric field in the drift volume of the TPC is an important criterion for precise tracking as the tracking capability of the TPC is strongly governed by the homogeneity of the electric field. Due to the lesser mobility of positive ions produced in primary ionization, their accumulation in the drift volume can distort the local electric field. In low-energy nuclear physics, this effect may be substantial due to the significant amount of ionization produced by the low-energy projectile and reaction products. Here we report the spatial information of primary space charges produced by cosmic muon and alpha particle obtained with geant4 1 and Heed 2 simulation packages. We have used photo absorption and ionization physics lists in geant4 for the simulation and compared the results with that of the Heed. The simulation results for the change in pressure of gas volume will be reported. These results can be used for finding the distortion of the electric field due to the space charge in the drift region of the TPC which can be helpful for designing an AT-TPC for low-energy nuclear reaction experiments.
We present X-ray light curves of Cygnus X-3 as measured by the recently launched AstroSat satellite. The light curve folded over the binary period of 4.8 hr shows a remarkable stability over the past ...45 years and we find that we can use this information to measure the zero point to better than 100 s. We revisit the historical binary phase measurements and examine the stability of the binary period over 45 years. We present a new binary ephemeris with the period and period derivative determined to an accuracy much better than previously reported. We do not find any evidence for a second derivative in the period variation. The precise binary period measurements, however, indicate a hint of short-term episodic variations in periods. Interestingly, these short-term period variations coincide with the period of enhanced jet activity exhibited by the source. We discuss the implications of these observations on the nature of the binary system.
Here we assess the predictive skill of short-range weather forecasts from the Weather Research and Forecasting (WRF) model with the help of micrometeorological tower observations. WRF model forecasts ...at a 3-h temporal resolution and 5000-m spatial resolution are compared with ground observations collected at micrometeorological towers during the year 2011 over the Indian landmass. Results show good agreement between the WRF model forecast and tower observed surface temperature and relative humidity, 10-m wind speed, and surface pressure. The WRF model simulations of surface energy fluxes, such as incoming shortwave, longwave radiation, and ground heat flux are also compared with micrometeorological tower measurements. Relatively high errors in incoming shortwave radiation flux may be attributed to the lack of accurate cloud prediction and the non-inclusion of aerosol load. The cyclic pattern of errors in surface relative humidity is found to be tightly and oppositely coupled with the incoming longwave radiation flux. Errors in soil heat fluxes during daytime hours are dominated by errors in the incoming shortwave radiation flux.
One of the major reasons of reluctance by industries to implement ultrafiltration (UF) of black liquor (BL) is flux decline and associated fouling. Several attempts have been made in the past to ...study and to analyze the performance of ultrafiltration of BL using various module combinations under different conditions. BL, spent liquor from alkaline sulfite pulping industries, is known to contain organics (mainly lignosulphonates of wide range of molecular weights) as well as inorganics; thus posing design restrictions for its treatment. The present work employs a laboratory fabricated stirred and rotating disk batch UF cell in an attempt to minimize flux decline and thereby obtain enhanced flux for the treatment of BL obtained from sulfite pulping industries. Asymmetric cellulose triacetate membrane of 5000-molecular weight cut-off was used for experimentations. Reduction of concentration polarization was observed with membrane rotation in this shear induced dynamic filtration unit and correlations have been obtained with different operating variables, like transmembrane pressure (TMP), stirrer speed and membrane rotation speed. The rejection of solutes, measured in terms of total solids (mostly containing lignosulphonates) was also correlated with different operating parameters. Pretreatment methods like, centrifugation, followed by microfiltration were utilized to remove any traces of suspended solids; thus minimizing the occurrences of membrane fouling. Pretreatment steps proved to be highly efficient in restoring the permeability of the membrane during experimentations. Finally, a new model was developed based on pore-plugging theory in order to assess the performance of UF, which clearly showed the reduction in pore-plugging phenomenon as a result of membrane rotation. Further, membrane rotating was proved to be more efficient in reducing concentration polarization compared to stirring action.
Resistant superficial dermatophytic infections of the skin and its appendages have emerged as a major health problem in India. Mutations in Squalene epoxidase gene have led to increasing incidence of ...resistance to terbinafine in dermatophytic isolates. We examined six patients with recalcitrant dermatophytosis attending Dermatology OPD at a tertiary care hospital and demonstrated terbinafine resistance by molecular method. Immediate hyperitivity (IH) reaction to Trichophytin antigen was highlighted in these patients. The patients were treated with alternate antifungals after demonstration of resistance to terbinafine based on the antifungal susceptibility testing (AFST). On follow up the patients responded well to the substitute but the duration of therapy had to be prolonged beyond six weeks.
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