Infrared emission from interstellar dust cloud with two embedded sources: IRAS 19181+1349

Mid and far infrared maps of many Galactic star forming regions show multiple peaks in close proximity, implying more than one embedded energy sources. With the aim of understanding such interstellar clouds better, the present study models the case of two embedded sources. A radiative transfer scheme has been developed to deal with an uniform density dust cloud in a cylindrical geometry, which includes isotropic scattering in addition to the emission and absorption processes. This scheme has been applied to the Galactic star forming region associated with IRAS 19181+1349, which shows observational evidence for two embedded energy sources. Two independent modelling approaches have been adopted, viz., to fit the observed spectral energy distribution (SED) best; or to fit the various radial profiles best, as a function of wavelength. Both the models imply remarkably similar physical parameters.Comment: 17 pages, 6 Figures, uses epsf.sty. To appear in Journal of Astronophysics & Astronom

An Eulerian–Eulerian formulation for erosion modelling: an alternate approach.

Sand is commonly produced besides petroleum fluids and it presents a major erosional hazard leading to pipe failures. Particle erosion is a complex process in which material is removed due to the repeated particle impacts. Conventionally, a CFD flow solver and computationally intensive lagrangian particle tracking sub–routines, known as Eulerian–Lagrangian (E–L) model, along with empirical erosion equations are used to predict the erosion rates. The present work introduces an Eulerian–Eulerian (E–E) approach in which the multiphase granular model resolves the solid phase and obviates the need of particles tracking. Particle–laden turbulent flow across a flow restrictor, based on an experimental study, is chosen for validation. Numerical experiments are done in Simcenter STAR–CCM+. Comparison with the experimental data demonstrate a good agreement and in particular, the E–E model yields reliable predictions of impact wear locations, erosion rates as those of E–L model. A 90° square bend is also simulated and comparison of erosion rates on the concave wall demonstrate that E–E model can be used as an alternate to computationally expensive approaches

Far Infrared Observations of the Galactic Star Forming Regions associated with IRAS 00338+6312 and RAFGL 5111

Two Galactic star forming regions, one in a very early phase of evolution and another evolved one, associated with the IRAS sources 00338+6312 and 03595+5110 (RAFGL 5111) respectively have been studied in detail. These sources have been mapped simultaneously in two far infrared bands at 143 & 185 \micron), with about 1.5 arcmin angular resolution, using the TIFR 100 cm balloon borne telescope. The HIRES processed IRAS maps at 12, 25, 60 & 100 \micron, have been used for comparison. Whereas IRAS 00338+6312 is resolved only in the TIFR bands, RAFGL 5111 is very well resolved in both the TIFR bands, as well as in at least 3 IRAS bands. The neighbouring fainter source IRAS 04004+5114 has also been resolved in the TIFR bands. Taking advantage of the identical beams in the two TIFR bands at 143 & 185 \micron, dust colour temperature, $T(143/185)$, and optical depth, $\tau_{150}$, maps have been generated for RAFGL 5111. These maps show interesting structural details. Radiative transfer modelling in spherical geometry has been carried out for individual sources. The best fit models are in good agreement with the observed spectral energy distribution (SED), radio continuum data etc. Another scheme of radiative transfer through the interstellar dust-gas cloud including the heavier elements has been used to predict ionic nebular line emission, which are in reasonable agreement with the measurements for RAFGL 5111. An important conclusion from the present study is that, for all the three sources (IRAS 00338+6312; 03595+5110; and 04004+5114, a faint source in the neighbourhood of RAFGL 5111), the best fit to the observed SED is obtained for a uniform density ($n(r) \sim r^0$) cloud

Comparison of Friedewald’s formula, modified Friedewald’s formula and Anandaraja’s formula with direct homogenous serum LDL cholesterol method in CHD patients

Background: Elevated serum Low-Density Lipoprotein Cholesterol (LDL-C) concentration is a well-known atherogenic risk factor with a high predictive value for coronary heart disease. An important aspect of the assessment of coronary heart disease risk for a dyslipidemic subject is the estimation of serum Low-Density Lipoprotein Cholesterol (LDL-C). There are many homogenous assays currently available for the estimation of serum LDL-C. Most clinical laboratories determine LDL-C (mg/dl) by Friedewald’s formula (FF), LD-=(TC)-HDL-C)-(TG/5), Modified Friedewald’s formula (MFF), LDL-C=(TC)-(HDL-C)-(TG/6), Recently Anandaraja and colleagues have derived a new formula for calculating LDL-C, AR-LDL-C=0.9 TC-(0.9 TG/5)-28.Methods: It is cross-sectional study. Lipid profile data was collected from known of CHD patients, who had come for lipid profile investigation to the Central Biochemistry laboratory of ACPM Medical College and hospital. LDL-C estimation was done by direct homogenous assay and also calculated using the Friedewald’s Formula, Modified Friedewald’s Formula and Anandaraja’s Formula for assessing and validity of the LDL cholesterol.Results: From the present study, The LDL-FF, MFW and AR are increased with levels of TGL > 200 mg/dl and decreased level of TC < 200 mg/dl seem to interfere with the estimation of Direct LDL cholesterolConclusions: Authors conclude that, LDL-C by direct method is most reliable and sensitive in CHD patients compare with FF, MFW, and ARF

Penaeid prawn fishery and its maximum sustainable yield at Versova, Mumbai

Penaeid prawn fishery at Versova, Mumbai was investigated for the ten-year period of 1988 to 1997. The average annual catch during the period was 3,764 t, of which the trawlers contributed 84.9% and 15.1% by the dol nets. The major species contributing to the fishery were Parapenaeopsis stylifera (61.2%), Solenocera crassicornis (12.4%), Metapenaeus affinis (8.9%) and M. brevicornis (8.5%)'in trawlers andP. stylifera (51.5%),S. crassicornis (28.3%) andP. hardwikii (11.0%) in dol nets. Month wise abundance, size range, mean size, maturity and sex ratio in the two gears averaged for the period are discussed. Trawling at Versova commenced in 1986-'87 and due to encouraging returns many dol net owners also shifted over to trawling. Consequently the catch of penaeid prawns also increased from 1,363.71 in 1988 to 4,740.71 in 1996, and thereafter it declined considerably. Using Schaefer's surplus yield model, maximum sustainable yield (MSY) and the related effort (FMSY) were estimated. The MSY was found to be 4,368.81 with the optimum effort of 3.75 X 105 hours of fishing for the dol nets and trawlers together, which corresponds to operation of 158 daily trawler trips and 38 dol net boats for the sustainable penaeid prawn fishery at Versova

Far and mid infrared observations of two ultracompact H II regions and one compact CO clump

Two ultracompact H II regions (IRAS 19181+1349 and 20178+4046) and one compact molecular clump (20286+4105) have been observed at far infrared wavelengths using the TIFR 1 m balloon-borne telescope and at mid infrared wavelengths using ISO. Far infrared observations have been made simultaneously in two bands with effective wavelengths of ~ 150 and ~ 210 micron, using liquid 3He cooled bolometer arrays. ISO observations have been made in seven spectral bands using the ISOCAM instrument; four of these bands cover the emission from Polycyclic Aromatic Hydrocarbon (PAH) molecules. In addition, IRAS survey data for these sources in the four IRAS bands have been processed using the HIRES routine. In the high resolution mid infrared maps as well as far infrared maps multiple embedded energy sources have been resolved. There are structural similarities between the images in the mid infrared and the large scale maps in the far infrared bands, despite very different angular resolutions of the two. Dust temperature and optical depth (tau_150 um) maps have also been generated using the data from balloon-borne observations. Spectral energy distributions (SEDs) for these sources have been constructed by combining the data from all these observations. Radiation transfer calculations have been made to understand these SEDs. Parameters for the dust envelopes in these sources have been derived by fitting the observed SEDs. In particular, it has been found that radial density distribution for three sources is diffrent. Whereas in the case of IRAS 20178+4046, a steep distribution of the form r^-2 is favoured, for IRAS 20286+4105 it is r^-1 and for IRAS 19181+1349 it the uniform distribution (r^0). Line ratios for PAH bands have generally been found to be similar to those for other compact H II regions but different from general H II regions.Comment: To appear in Astronomy & Astrophysics; (19 pages including 14 Figures and 6 Tables

A new scheme of radiation transfer in H II regions including transient heating of grains

A new scheme of radiation transfer for understanding infrared spectra of H II regions, has been developed. This scheme considers non-equilibrium processes (e. g. transient heating of the very small grains, VSG; and the polycyclic aromatic hydrocarbon, PAH) also, in addition to the equilibrium thermal emission from normal dust grains (BG). The spherically symmetric interstellar dust cloud is segmented into a large number of "onion skin" shells in order to implement the non-equilibrium processes. The scheme attempts to fit the observed SED originating from the dust component, by exploring the following parameters : (i) geometrical details of the dust cloud, (ii) PAH size and abundance, (iii) composition of normal grains (BG), (iv) radial distribution of all dust (BG, VSG & PAH). The scheme has been applied to a set of five compact H II regions (IRAS 18116- 1646, 18162-2048, 19442+2427, 22308+5812 & 18434-0242) whose spectra are available with adequate spectral resolution. The best fit models and inferences about the parameters for these sources are presented.Comment: 16 pages total including 3 tables and 2 figure