6,173 research outputs found

    Critical Shock Energy and Shock and Detonation Parameters of an Explosive

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    The present study deals with the connection between critical shock energy and detonation properties of an explosive. A relation for critical shock energy has been derived in terms of detonation velocity, width of reaction zone, initial density of the explosive, specific heat ratio of detonation products and either constants of linear relation between shock and particle velocity of the explosive or the constants of the Murnaghans type of equation of state of the explosive. These relations have been used to calculate the critical shock energy of RDX, HMX, RDX/TNT (60/40) and TNT explosives. The values of critical shock energies obtained in this study are in close agreement with those reported in the literature.Defence Science Journal, 2009, 59(4), pp.436-440, DOI:http://dx.doi.org/10.14429/dsj.59.154

    Anaesthetic considerations in patients with transverse myelitis

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    Transverse myelitis is an acute or subacute inflammatory disorder involving the spinal cord. Clinical signs are due to the involvement of the ascending and descending tracts in the transverse plane of the spinal cord. The most common cause is autoimmune. These patients may present with various clinical findings with which it is important for the anaesthesiologist to be familiar in order to manage such cases during the intraoperative and postoperative period. This report discusses issues relating to management of such cases

    Optical and Near-infrared survey of the stellar contents associated with the star-forming Complex Sh2-252

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    We present the analyses of the stellar contents associated with the HII region Sh2-252 using UBVRI photometry, slit and slitless spectroscopy along with the NIR data from 2MASS for an area ~1 degree x 1 degree. We studied the sub-regions of Sh2-252 which includes four compact-HII (CHII) regions, namely A, B, C and E and two clusters NGC 2175s and Teutsch 136 (Teu 136). Of the fifteen spectroscopically observed bright stars, eight have been identified as massive members of spectral class earlier than B3. From the spectro-photometric analyses, we derived the average distance of the region as 2.4+/-0.2 kpc and the reddening of the massive members is found to vary between 0.35 to 2.1 mag. We found that NGC 2175s and Teu 136, located towards the eastern edge of the complex are the sub-clusters of Sh2-252. The stellar surface density distribution in K-band shows clustering associated with the regions A, C, E, NGC 2175s and Teu 136. We have also identified the candidate ionizing sources of the CHII regions. 61 H_alpha emission sources are identified using slitless spectroscopy. The distribution of the H_alpha emission sources and candidate YSOs with IR excess on the V/(V-I) CMD shows that a majority of them have approximate ages between 0.1 - 5 Myr and masses in the range of 0.3 - 2.5 M_sun. The CMDs of the candidate YSOs in the individual regions also show an age spread of 0.1 - 5 Myr for each of them. We calculated the KLFs for the sub-regions A, C, E, NGC 2175s and Teu 136. Within errors, the KLFs for all the sub-regions are found to be similar and comparable to that of young clusters of age < 5 Myr. We also estimated the mass functions (MFs) of the PMS sample of the individual regions in the mass range of 0.3 - 2.5 M_sun. In general, the slopes of the MFs of all the sub-regions are found comparable to the Salpeter value.Comment: published in MNRA

    Deep optical survey of the stellar content of Sh2-311 region

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    The stellar content in and around Sh2-311 region have been studied using the deep optical observations as well as near-infrared (NIR) data from 2MASS. The region contains three clusters, viz. NGC 2467, Haffner 18 and Haffner 19. We have made an attempt to distinguish the stellar content of these individual regions as well as to re-determine their fundamental parameters such as distance, reddening, age, onto the basis of a new and more extended optical and infrared photometric data set. NGC 2467 and Haffner 19 are found to be located in the Perseus arm at the distances of 5.0 ±\pm 0.4 kpc and 5.7 ±\pm 0.4 kpc, respectively, whereas Haffner 18 is located at the distance of 11.2 ±\pm 1.0 kpc. The clusters NGC 2467 and Haffner 19 might have formed from the same molecular cloud, whereas the cluster Haffner 18 is located in the outer galactic arm, i.e. the Norma-Cygnus arm. We identify 8 class II young stellar objects (YSOs) using the NIR (JH)/(HK)(J - H)/(H - K) two colour diagram. We have estimated the age and mass of the YSOs identified in the present work and those by Snider et al. (2009) using the V/(VI)V/(V - I) colour-magnitude diagram. The estimated ages and mass range of the majority of the YSOs are \lesssim1 Myr and \sim0.4 - 3.5 \msun, respectively, indicating that these sources could be T-Tauri stars or their siblings. Spatial distribution of the YSOs shows that some of the YSOs are distributed around the H II region Sh2-311, suggesting a triggered star formation at its periphery.Comment: 19 pages, 13 figures, 9 table; Accepted for publication in New Astronom

    Screening of Selected Mulberry (Morus) Germplasm Varieties Through Propagation Parameters.

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    Nine mulberry varieties along with one check variety M5 were field tested at Bethamangala village of Kolar district, Karnataka. These mulberry varieties were evaluated for the propagation parameters, like sprouting, survival, shoot growth and rooting behaviour. Results showed that, sprouting percentage was above 95% inTR8, TR12 and S1708 mulberry varieties, while survival rate was as high as 93% in S1708. Mulberry variety S1708 recorded highest shoot length of 62.63cm and shorter shoot length was recorded in C6(35.55cm). Mulberry varieties studied exhibited considerable variations in fresh shoot and dry shoot weight. Among the mulberry varieties studied, Matigara black showed the longest root length (25.99cm) followed by TR12 (23.57cm) and TR8 (21.98cm). Numbers of roots / sapling were recorded more in Matigara black (42) and less in TR8 (14). Root volume was significantly high in Matigara black (16.27ml) and Tr20 (14.21ml) when compared to other varieties. Overall the mulberry variety S1708 showed better results in many propagation characters followed by TR8 and TR20 mulberry varieties. Key Words: Growth, mulberry germplasm; sprouting; survival; rooting; root length, root volume

    Supramolecular associations between atypical oxidative phosphorylation complexes of Euglena gracilis

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    In vivo associations of respiratory complexes forming higher supramolecular structures are generally accepted nowadays. Supercomplexes (SC) built by complexes I, III and IV and the so-called respirasome (I/III2/IV) have been described in mitochondria from several model organisms (yeasts, mammals and green plants), but information is scarce in other lineages. Here we studied the supramolecular associations between the complexes I, III, IV and V from the secondary photosynthetic flagellate Euglena gracilis with an approach that involves the extraction with several mild detergents followed by native electrophoresis. Despite the presence of atypical subunit composition and additional structural domains described in Euglena complexes I, IV and V, canonical associations into III2/IV, III2/IV2 SCs and I/III2/IV respirasome were observed together with two oligomeric forms of the ATP synthase (V2 and V4). Among them, III2/IV SC could be observed by electron microscopy. The respirasome was further purified by two-step liquid chromatography and showed in-vitro oxygen consumption independent of the addition of external cytochrome c

    Alpha-decay chains of 173288115^{288}_{173}115 and 172287115^{287}_{172}115 in the Relativistic Mean Field theory

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    In the recent experiments designed to synthesize the element 115 in the 243^{243}Am+48^{48}Ca reaction at Dubna in Russia, three similar decay chains consisting of five consecutive α\alpha-decays, and another different decay chain of four consecutive α\alpha-decays are detected, and the decay properties of these synthesized nuclei are claimed to be consistent with consecutive α\alpha-decays originating from the parent isotopes of the new element 115, 288115^{288}115 and 287115^{287}115, respectively\cite{ogan.03}. Here in the present work, the recently developed deformed RMF+BCS method with a density-independent delta-function interaction in the pairing channel is applied to the analysis of these newly synthesized superheavy nuclei 288115^{288}115, 287115^{287}115, and their α\alpha-decay daughter nuclei. The calculated α\alpha-decay energies and half-lives agree well with the experimental values and with those of the macroscopic-microscopic FRDM+FY and YPE+WS models. In the mean field Lagrangian, the TMA parameter set is used. Particular emphasis is paid on the influence to both the ground-state properties and energy surfaces introduced by different treatments of pairing. Two different effective interactions in the particle-particle channel, i.e., the constant pairing and the density-independent delta-function interaction, together with the blocking effect are discussed in detail.Comment: 17 pages, 5 figure
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