PTF 11kx: A Type Ia Supernova with a Symbiotic Nova Progenitor

There is a consensus that type Ia supernovae (SNe Ia) arise from the thermonuclear explosion of white dwarf stars that accrete matter from a binary companion. However, direct observation of SN Ia progenitors is lacking, and the precise nature of the binary companion remains uncertain. A temporal series of high-resolution optical spectra of the SN Ia PTF 11kx reveals a complex circumstellar environment that provides an unprecedentedly detailed view of the progenitor system. Multiple shells of circumstellar material are detected, and the SN ejecta are seen to interact with circumstellar material starting 59 days after the explosion. These features are best described by a symbiotic nova progenitor, similar to RS Ophiuchi

Variability Profiles of Millisecond X-Ray Pulsars: Results of Pseudo-Newtonian 3D MHD Simulations

We model the variability profiles of millisecond period X-ray pulsars. We performed three-dimensional magnetohydrodynamic simulations of disk accretion to millisecond period neutron stars with a misaligned magnetic dipole moment, using the pseudo-Newtonian Paczynski-Wiita potential to model general relativistic effects. We found that the shapes of the resulting funnel streams of accreting matter and the hot spots on the surface of the star are quite similar to those for more slowly rotating stars obtained from earlier simulations using the Newtonian potential. The funnel streams and hot spots rotate approximately with the same angular velocity as the star. The spots are bow-shaped (bar-shaped) for small (large) misalignment angles. We found that the matter falling on the star has a higher Mach number when we use the Paczynski-Wiita potential than in the Newtonian case. Having obtained the surface distribution of the emitted flux, we calculated the variability curves of the star, taking into account general relativistic, Doppler and light-travel-time effects. We found that general relativistic effects decrease the pulse fraction (flatten the light curve), while Doppler and light-travel-time effects increase it and distort the light curve. We also found that the light curves from our hot spots are reproduced reasonably well by spots with a gaussian flux distribution centered at the magnetic poles. We also calculated the observed image of the star in a few cases, and saw that for certain orientations, both the antipodal hot spots are simultaneously visible, as noted by earlier authors.Comment: 9 pages, 10 figures, accepted for publication in ApJ; corrected some typo

Calcium-rich gap transients in the remote outskirts of galaxies

From the first two seasons of the Palomar Transient Factory, we identify three peculiar transients (PTF09dav, PTF10iuv, PTF11bij) with five distinguishing characteristics: peak luminosity in the gap between novae and supernovae (M_R ≈ - 15.5 to -16.5), rapid photometric evolution (t_(rise) ≈12-15 days), large photospheric velocities (≈6000 to 11000 km s^(-1)), early spectroscopic evolution into nebular phase (≈1 to 3 months) and peculiar nebular spectra dominated by Calcium. We also culled the extensive decade-long Lick Observatory Supernova Search database and identified an additional member of this group, SN 2007ke. Our choice of photometric and spectroscopic properties was motivated by SN 2005E (Perets et al. 2010). To our surprise, as in the case of SN 2005E, all four members of this group are also clearly offset from the bulk of their host galaxy. Given the well-sampled early and late-time light curves, we derive ejecta masses in the range of 0.4--0.7 M_⊙. Spectroscopically, we find that there may be a diversity in the photospheric phase, but the commonality is in the unusual nebular spectra. Our extensive follow-up observations rule out standard thermonuclear and standard core-collapse explosions for this class of "Calcium-rich gap" transients. If the progenitor is a white dwarf, we are likely seeing a detonation of the white dwarf core and perhaps, even shock-front interaction with a previously ejected nova shell. In the less likely scenario of a massive star progenitor, a very non-standard channel specific to a low-metallicity environment needs to be invoked (e.g., ejecta fallback leading to black hole formation). Detection (or lack thereof) of a faint underlying host (dwarf galaxy, cluster) will provide a crucial and decisive diagnostic to choose between these alternatives

Estimation of Heat Loss in a Closed Vessel

Power cartridges are designed and developed for use in military aircraft in association withHigh Energy Materials Research Laboratory, Pune. During development, the cartridge is firedin a closed vessel to generate basic design parameters. When the cartridge is fired, the heat islost to the walls of the vessel due to conduction, convection, radiation, and to some extent, byexpansion of the vessel. An attempt has been made to estimate the heat loss from the vesseland the surrounding. The aim of this study was to lay down the technical results theoreticallyand their validation through experiments

A NEW REVERSED-PHASE HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY METHOD FOR THE SIMULTANEOUS ESTIMATION OF SERRATIOPEPTIDASE AND DICLOFENAC SODIUM IN BULK AND TABLET DOSAGE FORM

Objective: The objective is to study the development of a simple, rapid, specific, precise, and accurate reversed-phase high-performance liquid chromatography (RP-HPLC) method for the simultaneous estimation of serratiopeptidase (SER) and diclofenac (DC) sodium in bulk and tablet formulation.Methods: RP-HPLC method was developed for the simultaneous estimation of SER and DC sodium in tablet formulation. The separation was achieved by Kromasil C18 column (250 mm × 4.6 mm, 5 μm particle size) with phosphate buffer pH-7 and o-phosphoric acid:methanol:acetonitrile (5:4:1% v/v/v). Flow rate was maintained at 1 mL/min and UV detection was carried at 270 nm.Result: For RP-HPLC method, the retention time for SER and DC sodium was found to be 3.3833 min and 8.1667 min, respectively. The method was validated for accuracy, precision, and specificity. Linearity for SER and DC sodium was in the range of 5–50 μg/ml.Conclusion: The developed RP-HPLC method is simple, accurate, rapid, sensitive, precise, and economic. Hence, this method can be employed successfully for the estimation of SER and DC sodium in both bulk and tablet dosage forms

AN EXPERIMENTAL DESIGN APPROACH FOR OPTIMIZATION OF MODIFIED COLORIMETRIC FIRST-ORDER DERIVATIVE METHOD FOR ESTIMATION OF SERRALYSIN IN BULK AND PHARMACEUTICAL FORMULATION

Objective: The aim of the present work is to use experimental design to screen and optimize experimental variables for developing a colorimetric first-order derivative method for determining content of serralysin (SER) using biuret and Folin–Ciocalteu phenol reagent for stable color development. The method is based on the reaction of peptide bond in the protein with Biuret reagent in alkaline medium and further reaction of remaining tryptophan and tyrosine residues with Folin–Ciocalteu Phenol reagent to form a stable blue-colored complex (first-order derivative λmax 620 nm).Materials and Methods: A two-level full factorial design was utilized to screen the effect of Volume of NaOH (A), volume of biuret reagent (B), volume of Folin–Ciocalteu phenol reagent (C), and concentration of NaOH (D) on the formation of blue-colored SER - reagent complex (response - absorbance). A box Behnken experimental design with response surface methodology was then utilized to evaluate the main interaction and quadratic effects of these factors on the selected response.Results: With the help of a response surface plot and contour plot, the optimum values of the selected factors were determined and used for further experiments. These values were volume of NaOH (A) of 1.0 mL, volume of biuret reagent (B) of 0.25 mL, and volume of Folin–Ciocalteu phenol reagent (C) of 10 μL. The proposed method was validated according to the ICH Q2(R1) method validation guidelines. The developed colorimetric first-order derivative method was found to be simple, accurate, rapid, sensitive, precise, and economic. Further optimization of the method with experimental design approach makes it convenient for use in laboratory.Conclusion: The results of present study have clearly shown that an experimental design approach may be effectively applied to the optimization of a modified visible spectrophotometric method for estimation of SER in bulk and in pharmaceutical formulation with the least number of experimental runs possible. The method can be employed successfully for the estimation of SER in both bulk and tablet dosage form.Â

Effect of Wind Load on Structural Performance of Dimensionally Regular & Irregular High rise Buildings with different Outrigger Systems

Outriggers system is used as one of the best way of increasing the lateral stiffness and has been generally utilized in tall building structures. The outrigger system is very effective in increasing structure’s flexural stiffness. It is likewise viable in decreasing the horizontal top deflection and bending moments in the core of high-rise frame-core structures. This study presents the detailed analysis on how the top drift, inter-story drift, base moment in the core are influenced by the outriggers stiffness, outriggers optimum locations, columns axial stiffness and foundations flexibility. outrigger braced structures can strengthen a structure without disturbing its aesthetic appearance and this is a significant advantage over other lateral load resisting systems. The thesis compare between many outriggers systems including both concrete & steel Outriggers. The Rectangular shape & L- shaped building structures are taken for analysis. The study also presents simplified procedure to optimize the location of the outriggers that will result in a maximum reduction in the lateral displacement at the top of the building. The modeling of the structure is done using “ETABS” program. The investigation of the model is completed by comparable static technique. Finally, the thesis proposed a simplified analysis for outriggers structures with core for both regular and irregular high rise building

PSR J1909-3744, a Binary Millisecond Pulsar with a Very Small Duty Cycle

We report the discovery of PSR J1909-3744, a 2.95 millisecond pulsar in a nearly circular 1.53 day orbit. Its narrow pulse width of 43 microseconds allows pulse arrival times to be determined with great accuracy. We have spectroscopically identified the companion as a moderately hot (T = 8500 K) white dwarf with strong absorption lines. Radial velocity measurements of the companion will yield the mass ratio of the system. Our timing data suggest the presence of Shapiro delay; we expect that further timing observations, combined with the mass ratio, will allow the first accurate determination of a millisecond pulsar mass. We have measured the timing parallax and proper motion for this pulsar which indicate a transverse velocity of 140 (+80/-40) km/s. This pulsar's stunningly narrow pulse profile makes it an excellent candidate for precision timing experiments that attempt to detect low frequency gravitational waves from coalescing supermassive black hole binaries.Comment: 12 pages, 4 figures. Accepted for publication in ApJ

Direct esterification of poly (ethylene glycol) with amino acid hydrochlorides

Diesters of poly (ethylene glycol) with various a amino acid hydrochlorides were synthesized using dicyclohexyl carbodiimide as coupling agent. The use of hydrochloride as amino protecting group in dicyclohexyl carbodiimide mediated condensation reactions of amino acids was demonstrated for the first time