783 research outputs found
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
Emission and Performance Analysis of Green Gas in a VCR Engine
634-638The current advancement in producing the organic-based fuels, the gaseous fuel such as Green gas promises to be used in the vehicular engine. The gasification technique is used to gasify biomass such as rice husk, bagasse, wood chips resulting in production of organic green gas. It is prepared by gliding air and steam through the thick coal at different temperature range. Due to inertness, knocking tendency is higher in green gas, use of green gas tends to higher emission of CO, especially at lean condition through gasification technique. In our results of emission analysis, there is significant reduction in SOx and NOx from the engine running on green gas dual fuel operation. The use of green gas as an alternative fuel is founded as the sustainable and eco-friendly energy source
Impact of micro-indentation load/time and Zinc concentration on the thermo-mechanical characteristics of amorphous SeTeSn alloy
We have performed hardness measurement experiments under different loads and
loading times by performing micro-indentation marks in the present work.
Chalcogenide glasses (ChGs) comprising SeTeSn and
SeTeSnZn (where ) alloys are the
subject of micro-indentation tests in this work. We have utilized both
micro-indentation and optical microscopic methods to determine Vickers
hardness. Thermal glass transition phenomena have been identified through DSC
techniques. The modulus of elasticity (E), an essential mechanical property,
has been evaluated using established empirical equations. Further, we have
studied other mechanical parameters [e.g., minimal micro-void formation energy
(Eh), glass's fragility index (m), micro-void volume (Vh), etc.] and the
covalent character of the glassy system. Additionally, various physical
parameters, including density, molar volume, and compactness, have also been
determined
Utilisation of High Energy Propellant Waste in Manufacturing of Fired Clay Bricks to Enhance the Acoustic Properties
The disposal and waste management of solid high energy propellant (HEP) is a considerate conservational problem. HEP waste is currently disposed in open or confined burning which may cause environmental hazards. In this paper, we examined and discussed results on recycling of HEP waste into fired clay bricks baked in different orientation. HEP modified bricks with 1.5%, 3% and 5 wt. % HEP waste content were manufactured and tested, and then compared against virgin clay bricks without HEP content. The effect of directional orientation of bricks baked with varying HEP content on acoustic properties were experimented and discussed. The sound transmission loss decreases with increase in HEP waste due to formation of independently closed directional pores. The transmission loss of horizontally baked during firing of bricks is nearly 5dB lower than vertically baked bricks. Results of the experimental studies indicate that HEP waste can be utilised in fired clay bricks and different orientation baking further enhances the acoustic properties
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
Selective-area high-quality germanium growth for monolithic integrated optoelectronics
Cataloged from PDF version of article.Selective-area germanium (Ge) layer on silicon (Si)
is desired to realize the advanced Ge devices integrated with
Si very-large-scale-integration (VLSI) components. We demonstrate
the area-dependent high-quality Ge growth on Si substrate
through SiO2 windows. The combination of area-dependent
growth and multistep deposition/hydrogen annealing cycles has
effectively reduced the surface roughness and the threading dislocation
density. Low root-mean-square surface roughness of 0.6 nm
is confirmed by atomic-force-microscope analysis. Low defect density
in the area-dependent grown Ge layer is measured to be as low
as 1 × 107 cm−2 by plan-view transmission-electron-miscroscope
analysis. In addition, the excellent metal–semiconductor–metal
photodiode characteristics are shown on the grown Ge layer to
open up a possibility to merge Ge optoelectronics with Si VLSI
Hydrographic changes in the Agulhas Recirculation Region during the late Quaternary
The strength of Southern Hemisphere westerlies, as well as the positions of
the subtropical front (STF), Agulhas Current (AC) and Agulhas Return Current
(ARC) control the hydrography of the southwestern Indian Ocean. Although
equatorward migration of the STF and reduction in Agulhas leakage were
reported during the last glacial period, the fate of ARC during the last
glacial–interglacial cycle is not clear. Therefore, in order to understand
changes in the position and strength of ARC during the last
glacial–interglacial cycle, here we reconstruct hydrographic changes in the
southwestern Indian Ocean from temporal variation in planktic foraminiferal
abundance, stable isotopic ratio (δ<sup>18</sup>O) and trace elemental ratio
(Mg/Ca) of planktic foraminifera <i>Globigerina bulloides</i> in a core
collected from the Agulhas Recirculation Region (ARR) in the southwestern
Indian Ocean. Increased abundance of <i>G. bulloides</i> suggests that the
productivity in the southwestern Indian Ocean increased during the last glacial
period which confirms previous reports of high glacial productivity in the Southern Ocean. The
increased productivity was likely driven by the intensified Southern
Hemisphere westerlies supported by an equatorward migration of the
subtropical front. Increase in relative abundance of <i>Neogloboquadrina
incompta</i> suggests seasonally strong thermocline and enhanced advection of
southern source water in the southwestern Indian Ocean as a result of
strengthened ARC, right through MIS 4 to MIS 2, during the last glacial
period. Therefore, it is inferred that over the last glacial–interglacial
cycle, the hydrography of the southwestern Indian Ocean was driven by
strengthened westerlies, ARC as well as a migrating subtropical front
Stellar Wind Accretion in GX301-2: Evidence for a High-density Stream
The X-ray binary system GX301-2 consists of a neutron star in an eccentric
orbit accreting from the massive early-type star WRAY 977. It has previously
been shown that the X-ray orbital light curve is consistent with existence of a
gas stream flowing out from Wray 977 in addition to its strong stellar wind.
Here, X-ray monitoring observations by the Rossi X-ray Timing Explorer (RXTE)/
All-Sky-Monitor (ASM) and pointed observations by the RXTE/ Proportional
Counter Array (PCA) over the past decade are analyzed. We analyze both the flux
and column density dependence on orbital phase. The wind and stream dynamics
are calculated for various system inclinations, companion rotation rates and
wind velocities, as well as parametrized by the stream width and density. These
calculations are used as inputs to determine both the expected accretion
luminosity and the column density along the line-of-sight to the neutron star.
The model luminosity and column density are compared to observed flux and
column density vs. orbital phase, to constrain the properties of the stellar
wind and the gas stream. We find that the change between bright and medium
intensity levels is primarily due to decreased mass loss in the stellar wind,
but the change between medium and dim intensity levels is primarily due to
decreased stream density. The mass-loss rate in the stream exceeds that in the
stellar wind by a factor of 2.5. The quality of the model fits is significantly
better for lower inclinations, favoring a mass for WRAY 977 of 53 to 62 Msun.Comment: 19 pages, 6 figure
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