112 research outputs found
Antimycobacterial activity of linoleic acid and oleic acid obtained from the hexane extract of the seeds of Mesua ferrea L. and their in silico investigation
Tuberculosis is responsible for about 8 million deaths worldwide annually. The emergence of multidrug-resistant and extensively drug-resistant strains urgently requires the development of new drugs against tuberculosis. Drug discovery from plants against tuberculosis is an exciting area for exploration. In the present study, the fatty acids- linoleic and oleic acids isolated and identified from the seeds of the plant Mesua ferrea L. exhibited antimycobacterial activity. The analysis was done using Gas Chromatography-Mass Spectrometry and supplementary information was obtained using fourier transform-infra red and 1H and 13C nuclear magnetic resonance. The minimum inhibitory concentration of the purified fraction containing both the compounds was found to be 78 µg/mL. In silico molecular docking studies against the target proteins GlfT2, Inh A and mtKasB of Mycobacterium tuberculosis revealed high scores for both the compounds. Cytotoxicity studies of the compounds revealed no toxicity and high antioxidant activity was observed
Multi-Node Modeling of Cryogenic Tank Pressurization System using Generalized Fluid System Simulation Program
This paper presents a multi-node model of autogenous pressurization of cryogenic propellant in a flight tank using the Generalized Fluid System Simulation Program (GFSSP), a general purpose flow network code developed at NASA/Marshall Space Flight Center. Tests were conducted to measure the pressure and temperatures at the various axial locations of the stratified ullage at 75% and 45% fill level. Liquid nitrogen was pressurized by gaseous nitrogen from a supply tank while the drain valve from the tank remained closed during the pressurization process. The ullage was discretized into 25 uniformly distributed nodes: 5 in the radial direction and 5 in the axial direction assuming the flow to be axisymmetric. Heat and mass transfer between the liquid and vapor has been modeled at the liquid vapor interface. Heat transfer between wall and vapor at the ullage has been accounted for by assuming heat transfer occurs by natural convection. The model also accounts for heat leak to the tank through the insulation and metal wall by heat conduction. The predicted pressures and temperatures are compared with the measured data
Multi-Node Modeling of Cryogenic Tank Pressurization System Using Generalized Fluid System Simulation Program
Cryogenic Tanks are pressurized by inert gas such as Helium or Nitrogen to maintain the required pressure of the propellant delivered to the turbo-pump of a liquid rocket engine. Thermo-fluid system simulation tools are used to analyze the pressurization process of a cryogenic tank. Most system level codes (GFSSP and ROCETS) use single node1 to represent ullage which is the gaseous space in the tank. Ullage space in a cryogenic tank is highly stratified because the entering inert gas is at ambient temperature whereas the liquid propellant is at a cryogenic temperature. A single node model does not account for the effect of temperature gradient in the ullage. High fidelity Navier-Stokes based CFD model of Tank Pressurization is not practical for running a long duration transient model with thousands and millions of nodes. A possible recourse is to construct a multi-node model with system level code that can account for ullage stratification
Multi-Node Modeling of Cryogenic Tank Pressurization System using Generalized Fluid System Simulation Program
No abstract availabl
Chandra's tryst with SN 1995N
We present the spectroscopic and imaging analysis of a type IIn supernova SN
1995N observed with the Chandra X-ray observatory on 2004 March 27. We compare
the spectrum obtained from our Chandra observation with that of the previous
observation with ASCA in 1998. We find the presence of Neon lines in the
Chandra spectrum that were not reported in the ASCA observation. We see no
evidence of Iron in both epochs. The observed absorption column depth indicates
an extra component over and above the galactic absorption component and is
possibly due to a cool dense shell between the reverse-shock and the contact
discontinuity in the ejecta. The ASCA and the ROSAT observations suggested a
non-linear behavior of the X-ray light curve. However, with the higher spatial
resolution and sensitivity of Chandra, we separate out many nearby sources in
the supernova field-of-view that had additionally contributed to the supernova
flux due to the large Point Spread Function of the ASCA. Taking out the
contribution of those nearby sources, we find that the light curves are
consistent with a linear decline profile. We consider the light curve in the
high energy band separately. We discuss our results in the context of models of
nucleosynthesis and the interaction of the shock waves with the circumstellar
medium in core collapse supernovae.Comment: 35 pages, 12 figures, accepted for publication in Astrophysical
Journa
Exploring the logic of mobile search
After more than a decade of development work and hopes, the usage of mobile Internet has finally taken off. Now, we are witnessing the first signs of evidence of what might become the explosion of mobile content and applications that will be shaping the (mobile) Internet of the future. Similar to the wired Internet, search will become very relevant for the usage of mobile Internet. Current research on mobile search has applied a limited set of methodologies and has also generated a narrow outcome of meaningful results. This article covers new ground, exploring the use and visions of mobile search with a users' interview-based qualitative study. Its main conclusion builds upon the hypothesis that mobile search is sensitive to a mobile logic different than today's one. First, (advanced) users ask for accessing with their mobile devices the entire Internet, rather than subsections of it. Second, success is based on new added-value applications that exploit unique mobile functionalities. The authors interpret that such mobile logic involves fundamentally the use of personalised and context-based services
Results from an extensive simultaneous broadband campaign on the underluminous active nucleus M81*: further evidence for mass-scaling accretion in black holes
We present the results of a broadband simultaneous campaign on the nearby
low-luminosity active galactic nucleus M81*. From February through August 2005,
we observed M81* five times using the Chandra X-ray Observatory with the
High-Energy Transmission Grating Spectrometer, complemented by ground-based
observations with the Giant Meterwave Radio Telescope, the Very Large Array and
Very Large Baseline Array, the Plateau de Bure Interferometer at IRAM, the
Submillimeter Array and Lick Observatory. We discuss how the resulting spectra
vary over short and longer timescales compared to previous results, especially
in the X-rays where this is the first ever longer-term campaign at spatial
resolution high enough to nearly isolate the nucleus (17pc). We compare the
spectrum to our Galactic center weakly active nucleus Sgr A*, which has
undergone similar campaigns, as well as to weakly accreting X-ray binaries in
the context of outflow-dominated models. In agreement with recent results
suggesting that the physics of weakly-accreting black holes scales predictably
with mass, we find that the exact same model which successfully describes hard
state X-ray binaries applies to M81*, with very similar physical parameters.Comment: 58 pages (preprint version), 22 figures, accepted for publication in
the Astrophysical Journa
Coating with chitosan film of sea bream (Sparus aurata) fillets: determining shelf life in refrigerator conditions
A MISSING-LINK IN THE SUPERNOVA-GRB CONNECTION: THE CASE OF SN 2012ap
Gamma Ray Bursts (GRBs) are characterized by ultra-relativistic outflows,
while supernovae are generally characterized by non-relativistic ejecta. GRB
afterglows decelerate rapidly usually within days, because their low-mass
ejecta rapidly sweep up a comparatively larger mass of circumstellar material.
However supernovae, with heavy ejecta, can be in nearly free expansion for
centuries. Supernovae were thought to have non-relativistic outflows except for
few relativistic ones accompanied by GRBs. This clear division was blurred by
SN 2009bb, the first supernova with a relativistic outflow without an observed
GRB. Yet the ejecta from SN 2009bb was baryon loaded, and in nearly-free
expansion for a year, unlike GRBs. We report the first supernova discovered
without a GRB, but with rapidly decelerating mildly relativistic ejecta, SN
2012ap. We discovered a bright and rapidly evolving radio counterpart driven by
the circumstellar interaction of the relativistic ejecta. However, we did not
find any coincident GRB with an isotropic fluence of more than a sixth of the
fluence from GRB 980425. This shows for the first time that central engines in
type Ic supernovae, even without an observed GRB, can produce both relativistic
and rapidly decelerating outflows like GRBs.Comment: 8 pages, 5 figures, 1 table, accepted for publication in Ap
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