TNT Equivalency of Unconfined Aerosols of Propylene Oxide

The unconfined aerosols of propylene oxide (PO) are formed by dispersing the fuel in air. These aerosols undergo detonation by suitable initiation and produce high impulse blast. Tri-nitro Toluene (TNT) equivalence is an important parameter used to represent the power of explosive materials and compare their relative damage effects wrt TNT. The parameters commonly used for estimation of TNT equivalency are total energy of explosive source and properties of resulting blast wave, viz., blast peak overpressure and positive impulse. In the present study, the unconfined aerosols of 4.2 kg PO were formed by breaking open the cylindrical canister with the help of axially positioned central burster charge and then detonated using a secondary explosive charge after a preset time delay. The resulting blast profiles were recorded and the blast parameters were analysed. Being a non-ideal explosive source, the TNT equivalency depends on fraction of total energy utilised for blast formation, the rate of energy release, cloud dimensions, and concentration of fuel. Hence, various approaches based on energy release, experimental blast profiles, triangulated blast parameters, and ground reflected blast parameters were considered to determine the TNT equivalency of unconfined PO aerosols. It was observed that the TNT equivalency is not a single value but vary with distance. The paper provides various options for weapon designer to choose a suitable approach for considering TNT equivalency. The scaling laws established from the experimental data of unconfined aerosols of PO for blast peak over pressure and scaled impulse help in predicting the performance for different values of fuel weight and distance.Defence Science Journal, Vol. 64, No. 5, September 2014, pp.431-437, DOI:http://dx.doi.org/10.14429/dsj.64.685

Abundance of low energy (50-150 MeV) antiprotons in cosmic rays

The progress is presented of the nuclear emulsion experiment to determine abundance of low energy antiprotons in cosmic rays. No antiprotons have been detected so far at upper limit of p/p less than or similar to 4 x .0001 in the energy range 50 MeV to 15 MeV

First observations of the X-ray transient EXO 2030+375 with IBIS/ISGRI

We present a first INTEGRAL observation of the 42s transient X-ray pulsar EXO 2030+375 with IBIS/ISGRI. The source was detected during Cyg X-1 observations in December 2002. We analyzed observations during the outburst period from 9 to 21 December 2002 with a total exposure time of ~770 kiloseconds. EXO 2030+375 was almost always detected during single ~30 minute exposures in the 18-45 energy bands. The source light curve shows the characteristic outburst shape observed in this source.Comment: 4 pages, 3 figures (1 in CMYK color), accepted by Astronomy and Astrophysics, INTEGRAL special issue, 200

Estimating Be Star Disk Radii using H-alpha Emission Equivalent Widths

We present numerical models of the circumstellar disks of Be stars, and we describe the resulting synthetic H-alpha emission lines and maps of the wavelength-integrated emission flux projected onto the sky. We demonstrate that there are monotonic relationships between the emission line equivalent width and the ratio of the angular half-width at half maximum of the projected disk major axis to the radius of the star. These relationships depend mainly upon the temperatures of the disk and star, the inclination of the disk normal to the line of sight, and the adopted outer boundary for the disk radius. We show that the predicted H-alpha disk radii are consistent with those observed directly through long baseline interferometry of nearby Be stars (especially once allowance is made for disk truncation in binaries and for dilution of the observed H-alpha equivalent width by continuum disk flux in the V-band).Comment: 12 pages, 2 figures, ApJL in pres

BeppoSAX survey of Be/X-ray binary candidates

We present a BeppoSAX survey of five Be/X-ray binary candidates. We report on the identification of two of them, HD 110432 and HD 141926, as low luminosity Be/X-ray binaries. For HD 110432 we report on the detection of a pulsation period of ~14 ks. Because the luminosity of these sources is low and their spectra do not require non-thermal emission models, these systems are good Be+White Dwarf candidates. If the pulsation period for HD 110432 is confirmed, this system would be the most firm Be+WD candidate found up to date. The other three objects HD 65663, HD 249179 and BD+53 2262 did not show detectable X-ray emission. We argue that, while the properties of BD+53 2262 are still consistent with a quiescent Be+Neutron Star scenario, the lack of detection for the other two objects implies that they are most probably not X-ray binaries.Comment: 8 pages, 5 figures, accepted for publication in A&

4U2206+54 - an Unusual High Mass X-ray Binary with a 9.6 Day Orbital Period but No Strong Pulsations

Rossi X-ray Timing Explorer All-Sky Monitor observations of the X-ray source 4U2206+54, previously proposed to be a Be star system, show the X-ray flux to be modulated with a period of approximately 9.6 days. If the modulation is due to orbital variability then this would be one of the shortest orbital periods known for a Be star X-ray source. However, the X-ray luminosity is relatively modest whereas a high luminosity would be predicted if the system contains a neutron star accreting from the denser inner regions of a Be star envelope. Although a 392s pulse period was previously reported from EXOSAT observations, a reexamination of the EXOSAT light curves does not show this or any other periodicity. An analysis of archival RXTE Proportional Counter Array observations also fails to show any X-ray pulsations. We consider possible models that may explain the properties of this source including a neutron star with accretion halted at the magnetosphere and an accreting white dwarf.Comment: Accepted for publication in the Astrophysical Journa

Genetic divergence in chironji (Buchanania lanzan) under semi-arid ecosystem of western India

The present study was undertaken to evaluate the performance of 30 genotypes of chironji (Buchanania lanzan spreng) at Experimental Farm of Central Horticultural Experiment Station (CIAH), Vejalpur, Panchmahals (Godhra), Gujarat under rainfed hot semi-arid ecosystem of western India during the years 2011-2013. The results of study revealed that the different genotypes of chironji exhibited considerable variation for vegetative, floral, yield and physicochemical characters. The vegetative growth in terms of plant height, rootstock girth, plant spread (East-West) and plant spread (North-South) varied between 5.96-1.63m, 23.99-53.38cm, 1.40-5.10 m and 1.50-5.38 m, respectively. Time of flowering and fruit set ranged between 1st week February- 3rd week February and 3rd week February- 2nd week March, respectively. Maximum panicle length (35.13 cm) was noted in CHESC 1, while number of fruits per panicle was recorded highest in CHESC 7. Peak period of ripening in all the genotypes was recorded in May. Fruit yield, fruit weight, pulp per cent, TSS, acidity, total sugar and vitamin C varied from 1.00 kg-11.00 kg/plant, 0.94g-1.34g, 43.52- 63.06%, 19.05-23.900brix,1.00-1.34%,13.01-15.51% and 42.24-64.09%, respectively. Stone weight, shell weight, kernel weight and protein content ranged between 0.38-0.68g, 0.27-0.55 g, 0.08-0.15g and 23.53-31.36%, respectively. Based on the horticultural traits studied, the genotypes, CHESC7, CHESC2, CHESC 4 and CHESC11 were found to be promising under rainfed hot semi-arid conditions of western India. The genotype CHESC 7 was released as variety named as Thar Priya

Crustal Heating and Quiescent Emission from Transiently Accreting Neutron Stars

Nuclear reactions occurring deep in the crust of a transiently accreting neutron star efficiently maintain the core at a temperature >5e7 K. When accretion halts, the envelope relaxes to a thermal equilibrium set by the flux from the hot core, as if the neutron star were newly born. For the time-averaged accretion rates typical of low-mass X-ray transients, standard neutrino cooling is unimportant and the core thermally re-radiates the deposited heat. The resulting luminosity has the same magnitude as that observed from several transient neutron stars in quiescence. Confirmation of this mechanism would strongly constrain rapid neutrino cooling mechanisms for neutron stars. Thermal emission had previously been dismissed as a predominant source of quiescent emission since blackbody spectral fits implied an emitting area much smaller than a neutron star's surface. However, as with thermal emission from radio pulsars, fits with realistic emergent spectra will imply a substantially larger emitting area. Other emission mechanisms, such as accretion or a pulsar shock, can also operate in quiescence and generate intensity and spectral variations over short timescales. Indeed, quiescent accretion may produce gravitationally redshifted metal photoionization edges in the quiescent spectra (detectable with AXAF and XMM). We discuss past observations of Aql~X-1 and note that the low luminosity X-ray sources in globular clusters and the Be star/X-ray transients are excellent candidates for future study.Comment: 5 pages, 2 ps figures, uses AASTEX macros. To appear in ApJ letters, 10 September 1998. Revised to conform with journal; minor numerical correction

The Outbursts and Orbit of the Accreting Pulsar GS 1843-02 = 2S 1845-024

We present observations of a series of 10 outbursts of pulsed hard X-ray flux from the transient 10.6 mHz accreting pulsar GS 1843-02, using the Burst and Transient Source Experiment on the Compton Gamma Ray Observatory. These outbursts occurred regularly every 242 days, coincident with the ephemeris of the periodic transient GRO J1849-03 (Zhang et al. 1996), which has recently been identified with the SAS 3 source 2S 1845-024 (Soffitta et al. 1998). Our pulsed detection provides the first clear identification of GS 1843-02 with 2S 1845-024. We present a pulse timing analysis which shows that the 2S 1845-024 outbursts occur near the periastron passage of the neutron star's highly eccentric (e = 0.88+-0.01) 242.18+-0.01 day period binary orbit about a high mass (M > 7 solar masses) companion. The orbit and transient outburst pattern strongly suggest the pulsar is in a binary system with a Be star. Our observations show a long-term spin-up trend, with most of the spin-up occurring during the outbursts. From the measured spin-up rates and inferred luminosities we conclude that an accretion disk is present during the outbursts.Comment: Accepted for publication in Astrophysical Journa

Quasi-periodic flares in EXO 2030+375 observed with INTEGRAL

Context: Episodic flaring activity is a common feature of X-ray pulsars in HMXBs. In some Be/X-ray binaries flares were observed in quiescence or prior to outbursts. EXO 2030+375 is a Be/X-ray binary showing "normal" outbursts almost every ~46 days, near periastron passage of the orbital revolution. Some of these outbursts were occasionally monitored with the INTEGRAL observatory. Aims: The INTEGRAL data revealed strong quasi-periodic flaring activity during the rising part of one of the system's outburst. Such activity has previously been observed in EXO 2030+375 only once, in 1985 with EXOSAT. (Some indications of single flares have also been observed with other satellites.) Methods: We present the analysis of the flaring behavior of the source based on INTEGRAL data and compare it with the flares observed in EXO 2030+375 in 1985. Results: Based on the observational properties of the flares, we argue that the instability at the inner edge of the accretion disk is the most probable cause of the flaring activity.Comment: Accepted for publication in A&A Lette