554 research outputs found

    Supernova SN 2012dn: A spectroscopic clone of SN 2006gz

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    We present optical and UV analysis of the luminous type Ia supernova SN 2012dn covering the period \sim -11 to +109 days with respect to the BB band maximum, that occurred on JD 2456132.89 ±\pm 0.19, with an apparent magnitude of mBmaxm_{B}^\text{max} = 14.38 ±\pm 0.02. The absolute magnitudes at maximum in BB and VV bands are MBmax=19.52±0.15M_{B}^\text{max} = -19.52 \pm 0.15 and MVmax=19.42±0.15M_{V}^\text{max} = -19.42 \pm 0.15, respectively. SN 2012dn is marginally luminous compared to normal type Ia supernovae. The peak bolometric luminosity of logLbolmax=43.27±0.06\log L_\text{bol}^\text{max} = 43.27 \pm 0.06 erg s1^{-1} suggests that 0.82±0.120.82 \pm 0.12 M_\odot of 56^{56}Ni was synthesized in the explosion. The decline rate Δm15(B)true=0.92±0.04\Delta m_{15}(B)_\text{true}= 0.92 \pm 0.04 mag is lower than that of normal type Ia supernovae, and similar to the luminous SN 1991T. However, the photometric and spectroscopic behaviour of SN 2012dn is different from that of SN 1991T. Early phase light curves in RR and II bands are very broad. The II band peak has a plateau-like appearance similar to the super-Chandra SN 2009dc. Pre-maximum spectra show clear evidence of C\,{\sc ii} 6580 \AA\, line, indicating the presence of unburned materials. The velocity evolution of C\,{\ sc ii} line is peculiar. Except for the very early phase (\sim-13 d), the C\,{\sc ii} line velocity is lower than the velocity estimated using the Si\,{\sc ii} line. During the pre-maximum and close to maximum phase, to reproduce observed shape of the spectra, the synthetic spectrum code {\sc syn++} needs significantly higher blackbody temperature than those required for normal type Ia events. The photospheric velocity evolution and other spectral properties are similar to those of the carbon-rich SN 2006gz.Comment: Accepted for publication in MNRAS, 19 pages, 20 figure

    Development of Corrugated Fiber Board Cartons for Long Distance Transport of Tomato in India

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    Tomato growers of Gujarat , north-west India , traditionally send produce to wholesale market in Ahmedabad city for auction. Growing areas lie about 250-300 km from the city. Growers were constrained to sell there even if the prices were not attractive which the case usually as season advanced was. Lack of sturdy packaging deterred them from sending produce to more distant markets such as Bombay ( 600 km ) , Delhi ( 900 km) or Bangalore ( 2000) . Peti, the box used presently, made of strips of wood nailed together does not protect the produce adequately. Although, there are many large packaging firms in the region producing boxes for various consumer products, problem of tomato growers was not recognized. Their view was that tomato being a low-value commodity, growers will not buy better packaging. Being mostly small, growers were not organized enough to raise funds to sponsor research at public R&D institutions in the area. That task was therefore taken up. Boxes that protected the produce better on long journey and were affordable were designed and introduced successfully in the region. This paper describes the development.

    ASASSN-14dq: A fast-declining type II-P Supernova in a low-luminosity host galaxy

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    Optical broadband (UBVRI) photometric and low-resolution spectroscopic observations of the type II-P supernova (SN) ASASSN-14dq are presented. ASASSN-14dq exploded in a low-luminosity/metallicity host galaxy UGC 11860, the signatures of which are present as weak iron lines in the photospheric phase spectra. The SN has a plateau duration of \sim\,90 d, with a plateau decline rate of 1.38 mag (100d)1\rm mag\ (100 d)^{-1} in V-band which is higher than most type II-P SNe. ASASSN-14dq is a luminous type II-P SN with a peak VV-band absolute magnitude of -17.7±\,\pm\,0.2 mag. The light curve of ASASSN-14dq indicates it to be a fast-declining type II-P SN, making it a transitional event between the type II-P and II-L SNe. The empirical relation between the steepness parameter and 56Ni\rm ^{56}Ni mass for type II SNe was rebuilt with the help of well-sampled light curves from the literature. A 56Ni\rm ^{56}Ni mass of \sim\,0.029 M_{\odot} was estimated for ASASSN-14dq, which is slightly lower than the expected 56Ni\rm ^{56}Ni mass for a luminous type II-P SN. Using analytical light curve modelling, a progenitor radius of 3.6×1013\rm \sim3.6\times10^{13} cm, an ejecta mass of 10 M\rm \sim10\ M_{\odot} and a total energy of 1.8×1051\rm \sim\,1.8\times 10^{51} ergs was estimated for this event. The photospheric velocity evolution of ASASSN-14dq resembles a type II-P SN, but the Balmer features (Hα\alpha and Hβ\beta) show relatively slow velocity evolution. The high-velocity Hα\alpha feature in the plateau phase, the asymmetric Hα\alpha emission line profile in the nebular phase and the inferred outburst parameters indicate an interaction of the SN ejecta with the circumstellar material (CSM).Comment: 28 pages, 29 figures, Accepted in MNRA

    Herstellung rekombinanter Antikörperfragmente für die Immun-PCR und Aufklärung der Primärstruktur der Maltosephosphorylase aus Lactobacillus brevis

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    Im Rahmen des EU-Projektes BE 97-428 (ULISA) wurde die nt-Sequenz der VH-/VL-Regionen der mAK gegen humanes H-FABP (IT13B8/E6) und CEA (2-4.4, 3-55.4) aufgeklärt. Funktionelle Fab- und scFv-Fragmente des mAK IT13B8/E6 wurden exprimiert und via ELISA detektiert. Bei Untersuchung des Klons IT13B8 wurde ein nicht-produktives VH-Gen entdeckt. Die Produktion der scFv-Fragmente erfolgte im Vektor pASKscFvIT1 ohne vorangehende SOE-PCR. Funktionelles CSav wurde zur Produktion von scFv-CSav-Fragmenten exprimiert. Zur Detektion der I-PCR-Produkte wurde ein PCR-ELISA-Verfahren optimiert. Der Nachweis von Pi mittels Enzymbiosensor erfolgt über Maltosephosphorylase (mapA) aus Lactobacillus brevis. Die ermittelte nt-Sequenz umfasst ca. 98,5 Prozent des nativen mapA-Gens. MALDI-TOF-Analyse ergab, dass der C-Terminus des mapA weitere 10-12 AS aufweist. Mittels der nt-Sequenz und Röntgenkristallographie wurde die Tertiärstruktur der mapA ermittelt und Hinweise auf den molekularen Katalysemechanismus erhalten

    Microstructure evolution and densification during spark plasma sintering of nanocrystalline W-5wt.%Ta alloy

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    The present work reports the effect of Ta on densification and microstructure evolution during non-isothermal and spark plasma sintering of nanocrystalline W. Nanocrystalline W-5wt.%Ta alloy powder was synthesized using mechanical alloying. The nanocrystalline powder was characterized thoroughly using X-ray diffraction line profile analysis. Furthermore, the shrinkage behavior of nanocrystalline powder was investigated during non-isothermal sintering using dilatometry. Subsequently, the alloy powder was consolidated using spark plasma sintering up to 1600 {\deg}C. The role of Ta on stabilizing the microstructure during spark plasma sintering of nanocrystalline W was investigated in detail using electron backscatter diffraction. The average grain size of spark plasma sintered W-5wt.%Ta alloy was observed as 1.73 micron.Comment: 14 pages, 3 figure
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