A finite element solver for 3-D compressible viscous flows

Computation of the flow field inside a space shuttle main engine (SSME) requires the application of state of the art computational fluid dynamic (CFD) technology. Several computer codes are under development to solve 3-D flow through the hot gas manifold. Some algorithms were designed to solve the unsteady compressible Navier-Stokes equations, either by implicit or explicit factorization methods, using several hundred or thousands of time steps to reach a steady state solution. A new iterative algorithm is being developed for the solution of the implicit finite element equations without assembling global matrices. It is an efficient iteration scheme based on a modified nonlinear Gauss-Seidel iteration with symmetric sweeps. The algorithm is analyzed for a model equation and is shown to be unconditionally stable. Results from a series of test problems are presented. The finite element code was tested for couette flow, which is flow under a pressure gradient between two parallel plates in relative motion. Another problem that was solved is viscous laminar flow over a flat plate. The general 3-D finite element code was used to compute the flow in an axisymmetric turnaround duct at low Mach numbers

X-ray properties of UV-selected star forming galaxies at z~1 in the Hubble Deep Field North

We present an analysis of the X-ray emission from a large sample of ultraviolet (UV) selected, star forming galaxies with 0.74<z<1.32 in the Hubble Deep Field North (HDF-N) region. By excluding all sources with significant detected X-ray emission in the 2 Ms Chandra observation we are able to examine the properties of galaxies for which the emission in both UV and X-ray is expected to be predominantly due to star formation. Stacking the X-ray flux from 216 galaxies in the soft and hard bands produces significant detections. The derived mean 2-10 keV rest-frame luminosity is 2.97+/-0.26x10^(40) erg/s, corresponding to an X-ray derived star formation rate (SFR) of 6.0+/-0.6 Msolar/yr. Comparing the X-ray value with the mean UV derived SFR, uncorrected for attenuation, we find that the average UV attenuation correction factor is \~3. By binning the galaxy sample according to UV magnitude and colour, correlations between UV and X-ray emission are also examined. We find a strong positive correlation between X-ray emission and rest-frame UV emission. A correlation between the ratio of X-ray-to-UV emission and UV colour is also seen, such that L(X)/L(UV) increases for redder galaxies. Given that X-ray emission offers a view of star formation regions that is relatively unaffected by extinction, results such as these can be used to evaluate the effects of dust on the UV emission from high-z galaxies. For instance we derive a relationship for estimating UV attenuation corrections as a function of colour excess. The observed relation is inconsistent with the Calzetti et al. (2000) reddening law which over predicts the range in UV attenuation corrections by a factor of ~100 for the UV selected z~1 galaxies in this sample (abridged).Comment: 10 pages, 7 figures, accepted for publication in MNRA

Ethnomedicinal Observations Among the Kondareddis of Khammam District, Andhra Pradesh, India

Ethnomedicinal information of Kondareddis has been collected from Khammam district of Andhra Pradesh, India during 2006-2008. A total of 40 plant species belonging to 39 genera and 31 families were used in traditional medicine to heal different diseases. The present work is an attempt to identify and conserve the medicinal plants in Khammam district. The study shows a high degree of ethnobotanical novelty and the use of plants among the Kondareddis reflects the revival of interest in traditional folk culture

Ethnobotanical Survey on Respiratory Disorders in Eastern Ghats of Andhra Pradesh, India

An Ethnopharmacological survey of the Eastern Ghats region of Andhra Pradesh, comprising Chittoor, Cuddapah, East Godavari, Guntur, Khammam, Krishna, Kurnool, Srikakulam, Visakhapatnam, Vijayanagaram and the West Godavari districts, was conducted during 2000-2005. Eighty-four species of folk drug plants belonging to 72 genera and 41 families were found to be used as a remedy for respiratory disorders by the rural people and forest ethnic people (Chenchus, Erukulas, Lambadas, Koyas, Kondareddies, Nukadoras, Yanadis). The scientific, vernacular and family names of these medicinal plants, along with the parts used and the mode of their administration are enumerated

The dynamics and control of large flexible space structures-V

A general survey of the progress made in the areas of mathematical modelling of the system dynamics, structural analysis, development of control algorithms, and simulation of environmental disturbances is presented. The use of graph theory techniques is employed to examine the effects of inherent damping associated with LSST systems on the number and locations of the required control actuators. A mathematical model of the forces and moments induced on a flexible orbiting beam due to solar radiation pressure is developed and typical steady state open loop responses obtained for the case when rotations and vibrations are limited to occur within the orbit plane. A preliminary controls analysis based on a truncated (13 mode) finite element model of the 122m. Hoop/Column antenna indicates that a minimum of six appropriately placed actuators is required for controllability. An algorithm to evaluate the coefficients which describe coupling between the rigid rotational and flexible modes and also intramodal coupling was developed and numerical evaluation based on the finite element model of Hoop/Column system is currently in progress

Stochastic Model and Computational Measures of Batch Process Queuing System with Hetero Multiservers

Multiprocessor system models at present are very important and widely used in modelling transaction processing systems, communication networks, mobile networks, and flexible machine shops with groups of machines. Heterogeneous processors system with one main server and several identical servers are studied. In this paper, reconfiguration and rebooting delays are considered to study the performance measures for both bounded and unbounded system. Numerical results are presented for various performability parameters

Ru (III) Catalyzed Oxidation of Aliphatic Ketones by N-Bromosuccinimide in Aqueous Acetic Acid: A Kinetic Study

Kinetics of Ru (III) catalyzed oxidation of aliphatic ketones such as acetone, ethyl methyl ketone, diethyl ketone, iso-butylmethyl ketone by N-bromosuccinimide in the presence of Hg(II) acetate have been studied in aqueous acid medium. The order of [N-bromosuccinimide] was found to be zero both in catalyzed as well as uncatalyzed reactions. However, the order of [ketone] changed from unity to a fractional one in the presence of Ru (III). On the basis of kinetic features, the probable mechanisms are discussed and individual rate parameters evaluated

FACTORIAL STUDIES ON ENHANCEMENT OF DISSOLUTION RATE AND FORMULATION OF ACECLOFENAC TABLETS EMPLOYING Î’CDAND KOLLIPHOR HS15

Aceclofenac is an effective anti inflammatory and analgesic drug. It belongs to class II under Biopharmaceutical classification system and exhibit low and variable oral bioavailability due to its poor solubility. It is practically insoluble in water and aqueous fluids and its oral absorption is dissolution rate limited. It needs enhancement in solubility and dissolution rate for improvement of its oral bioavailability and therapeutic efficacy. The objective of the present study is to enhance the dissolution rate and formulation development of aceclofenac tablets with fast dissolution characteristics employing βCD and Kolliphor HS15, a non ionic surfactant. The individual and combined effects of βCD (factor A) and Kolliphor HS15 (factor B) on the dissolution rate of aceclofenac from solid inclusion complexes and their tablets were evaluated in a series of 22 factorial experiments. The feasibility of formulating aceclofenac - βCD-Kolliphor HS15 inclusion complexes into tablets with fast dissolution rate characteristics was also investigated. Kolliphor HS15 has not been investigated earlier for this purpose. The individual and combined effects of βCD and Kolliphor HS15 in enhancing the dissolution rate and dissolution efficiency of aceclofenac from solid inclusion complexes and their tablets were highly significant (P &lt; 0.01). The dissolution of aceclofenac was rapid and higher in the case of aceclofenac- βCD and aceclofenac- βCD - Kolliphor HS15 complexes prepared when compared to aceclofenac pure drug. β CD alone gave a 8.66 fold increase and in combination with Kolliphor HS15 it gave 9.85 fold increase in the dissolution rate of (K1) of aceclofenac. Aceclofenac –βCD – Kolliphor HS15 inclusion complexes could be formulated into compressed tablets by wet granulation method and the resulting tablets also gave rapid and higher dissolution of aceclofenac. Aceclofenac tablets formulated with βCD and Kolliphor HS15 individually gave 4.75 and 6.1 fold increase in the dissolution rate and those containing drug - βCD -Kolliphor HS15 complex gave much higher enhancement (21.35 fold) in the dissolution rate when compared to tablets formulated with aceclofenac pure drug. Combination of βCD and Kolliphor HS15 gave much higher enhancement in the dissolution rate of aceclofenac tablets than is possible with them individually. A combination of βCD with Kolliphor HS15 is recommended to enhance the dissolution rate in the formulation development of aceclofenac tablets with fast dissolution rate characteristics