432 research outputs found
Assessment of two versions of regional climate model in simulating the Indian Summer Monsoon over South Asia CORDEX domain
This study assess the performance of two versions of Regional Climate Model (RegCM) in simulating the Indian summer monsoon over South Asia for the period 1998 to 2003 with an aim of conducting future climate change simulations. Two sets of experiments were carried out with two different versions of RegCM (viz. RegCM4.2 and RegCM4.3) with the lateral boundary forcings provided from European Center for Medium Range Weather Forecast Reanalysis (ERA-interim) at 50 km horizontal resolution. The major updates in RegCM4.3 in comparison to the older version RegCM4.2 are the inclusion of measured solar irradiance in place of hardcoded solar constant and additional layers in the stratosphere. The analysis shows that the Indian summer monsoon rainfall, moisture flux and surface net downward shortwave flux are better represented in RegCM4.3 than that in the RegCM4.2 simulations. Excessive moisture flux in the RegCM4.2 simulation over the northern Arabian Sea and Peninsular India resulted in an overestimation of rainfall over the Western Ghats, Peninsular region as a result of which the all India rainfall has been overestimated. RegCM4.3 has performed well over India as a whole as well as its four rainfall homogenous zones in reproducing the mean monsoon rainfall and inter-annual variation of rainfall. Further, the monsoon onset, low-level Somali Jet and the upper level tropical easterly jet are better represented in the RegCM4.3 than RegCM4.2. Thus, RegCM4.3 has performed better in simulating the mean summer monsoon circulation over the South Asia. Hence, RegCM4.3 may be used to study the future climate change over the South Asia
Endoscopic Management of Perforation of Right Hepatic Duct Following Non-Surgical Abdominal Trauma
Isolated bile duct injuries after blunt abdominal trauma are rare. Surgery is the usual mode of treatment. We report a patient with a right hepatic duct injury following blunt abdominal trauma who was managed successfully by endoscopic papillotomy
REGENERATION AND ABNORMALITY IN BENTHIC FORAMINIFER ROSALINA LEEI: IMPLICATIONS IN RECONSTRUCTING PAST SALINITY CHANGES
A laboratory culture experiment has been conducted to assess the response of marginal marine benthic foraminifer Rosalina leei to salinity and associated pH changes. Live specimens of Rosalina leei were subjected to a range (10-35 psu) of salinity. It was observed that hyposaline condition leads to dissolution of the calcareous tests. However, if the hyposaline condition persists only for a short period, then even after considerable dissolution, specimens were able to regenerate the dissolved part of the test. Additionally, in all the specimens subjected to lower than normal salinity, the regenerated chambers were abnormal. The abnormalities included smaller or larger chambers and addition of new chambers in planes different than the normal plane of the tests. The regenerated specimens, however, attained a final size almost equal to that of control specimens that were not subjected to hyposaline conditions. The differential response of R. leei was attributed to decreased seawater pH under hyposaline condition. The findings can help understand the increased abundance of abnormal specimens under ecologically stressed environments.
Effect of Nozzle Divergence Angle on Plume Expansion In Outer-Space Conditions
We carry out numerical simulations to investigate
the effect of nozzle divergence angle on back flow of
plume expansion into rarefied atmosphere.
Results are
obtained using open source compressible computational
fluid dynamics (CFD) solver.
Non-equilibrium slip and
jump boundary conditions for velocity and temperature are
implemented to capture rarefaction rarefaction effects in
the slip flow regime. The solver has been validated with
the experimental data for a nozzle flow in the slip flow
regime. We explore the non-linear non-equilibrium gas flow
physics of a supersonic jet expansion. We report results of
pressure, heat and drag coefficients for different divergent
angles (
12
0
,
15
0
and
20
0
) at 80 km altitude conditions. The
slip based results for heat loads significantly under-predict
the no-slip ones, while for pressure and drag coefficients,
deviations are found to be minute. It is noticed that thrust
coefficient of nozzle increases with increase in divergence
angle, however, nozzle with divergent angle of
15
0
led to
minimum drag and heat transfer load on the critical region.
The current study is important from the perspective of the
overall aero-thermodynamic design of a typical supersonic rocket model operating under rarefied conditions
Study on High Energy Propellant Waste in the Processing of Fired Clay Bricks
Utilisation of propellant waste in fabrication of bricks is not only used as efficient waste disposal method but also to get better functional properties. In the present study, high energy propellant (HEP) waste additive mixed with soil and fly ash in different proportions during manufacturing of bricks has been investigated experimentally. X-ray diffraction (XRD) studies were carried out to confirm the brick formation and the effect of HEP waste. Ceramic bricks were fabricated with HEP waste additive in proper proportions i.e. 0.5 wt %, 1.0 wt %, 1.5 wt %, 2.0 wt %, 2.5 wt %, 3 wt %, 3.5 wt %, and 4 wt % and then evaluated for water absorption capability and compressive strength. Compressive strength of 6.7 N/mm2, and Water absorption of 22 % have been observed from modified fired bricks impregnated with HEM waste additive. Scanning electron microscopy (SEM) studies were carried out to analyze the effect of HEP waste additive on pore formation and distribution in the bricks. Further, the heat resulting from decomposition of propellants can cause a decrease in the energy required of baking process. The process of manufacturing of bricks with HEP waste additive is first of its kind till date
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