Hall Effects on MHD Flow Through a Porous Straight Channel

The effect of Hall currents on the flow of a viscous incompressible slightly conducting fluid through a porous straight channel under a uniform transverse magnetic field is considered. The pressure gradient is taken as constant quantity and the case of steady flow is obtained by taking the time since the start of the motion to be infinite. Skin friction, temperature distribution and coefficients of heat transfer at both the plates have been evaluated. The effects of Hall parameter, magnetic parameter and Reynolds number on the above physical quantities have been investigated. Velocity distribution when the pressure gradient (i) varies linearly with time, and (ii) decreases exponentially with time has also been evaluated

Magneto Hydrodynamic Flow of a Viscous Incompressible Fluid Between a Parallel Flat Wall and a Long Wavy Wall

Magneto-hydrodynamic flow of a viscous incompressible slightly conducting fluid between a parallel flat wall and a long wavy wall has been studied. The velocity distribution, the coefficient of skin friction and temperature distribution has been evaluated. The effects of magnetic, suction and frequency parameters are investigated on velocity, the coefficient of skin friction and temperature distribution

Studies on atmospheric gravity wave activity in the troposphere and lower stratosphere over a tropical station at Gadanki

MST radars are powerful tools to study the mesosphere, stratosphere and troposphere and have made considerable contributions to the studies of the dynamics of the upper, middle and lower atmosphere. Atmospheric gravity waves play a significant role in controlling middle and upper atmospheric dynamics. To date, frontal systems, convection, wind shear and topography have been thought to be the sources of gravity waves in the troposphere. All these studies pointed out that it is very essential to understand the generation, propagation and climatology of gravity waves. In this regard, several campaigns using Indian MST Radar observations have been carried out to explore the gravity wave activity over Gadanki in the troposphere and the lower stratosphere. The signatures of the gravity waves in the wind fields have been studied in four seasons viz., summer, monsoon, post-monsoon and winter. The large wind fluctuations were more prominent above 10 km during the summer and monsoon seasons. The wave periods are ranging from 10 min-175 min. The power spectral densities of gravity waves are found to be maximum in the stratospheric region. The vertical wavelength and the propagation direction of gravity waves were determined using hodograph analysis. The results show both down ward and upward propagating waves with a maximum vertical wave length of 3.3 km. The gravity wave associated momentum fluxes show that long period gravity waves carry more momentum flux than the short period waves and this is presented

SIMULTANIOUS DETERMINATION OF ANTIRETROVIRAL DRUGS EMTRICITABINE AND TENOFOVIR DESOPROXIL FUMERATE BY A STABILITY INDICATING RP-HPLC METHOD

Objective: The objective of the present investigation is to develop a stability indicating RP-HPLC method for the simultaneous estimation of Emtricitabine (EMT) and Tenofovir Desoproxil Fumerate (TDF) in pure and tablet dosage forms.Methods: Waters (Alliance) HPLC 2695 series systems equipped with UV detector was adopted for the chromatographic analysis. The separation was achieved by injecting 20 µl of working standard solution of concentration 60 µg/ml of EMT and 90 µg/ml of TDF into the Inertsil ODS C-18 (250 mm x 4.6 mm, 5 µm) column maintained at ambient temperature, elution was carried out by 0.1% triflouro acetic acid (TFA) buffer and methanol in the ratio 39:61 (v/v) as mobile phase at a flow rate of 1.2 ml/min, and the detection at a wavelength at 261 nm.Results: The system suitability parameters such as tailing factor (1.41&1.43), theoretical plates (2470&3059), resolution (4.21) and chromatographic parameters like retention time (2.387&3.293 min), peak area (147228&250057), peak height (20731&26892) of EMT and TDF were evaluated. The developed method was validated in terms precision (for system precision and method precision, the %RSD was found to be 0.4637&0.3176 and 0.3502&0.2789 for EMT and TDF respectively), accuracy (percent of recovery was found to be 99.21-100.16&100.78-101.16), linearity (20-100µg/ml&30-150 µg/ml), limit of detection (0.48&0.56 µg/ml), limit of quantitation (1.64&1.89 µg/ml) for EMT and TDF respectively. The developed method was applied for the determination of assay of Truvada and the percent of assay was found to be in the range of 100.74-101.56.Conclusion: A simple, rapid and economic RP-HPLC method for simultaneous determination of EMT and TDF in bulk and formulations was developed and validated. The developed method was found to be precise, accurate, linear, robust and rugged. This method was successfully applied for the assay of Truvada; hence it can be adopted for the determination of quality in any quality control laboratory.Â

First report of Groundnut Bud Necrosis Virus infecting Taro (Colocasia esculenta).

Abstract The natural occurrence of Groundnut Bud Necrosis Virus (GBNV) on Colocasia esculenta was detected by enzyme linked immunosorbent assay using an antiserum raised against GBNV and reverse transcription polymerase chain reaction using coat protein specific primers. Sequence analysis showed 93-99% and 95-99% identity at nucleotide and amino acid levels respectively with other reported GBNV isolates

Study on special ABL features observed over Tirupati using sodar

47-52A monostatic acoustic sounder (sodar) has been developed in the Department of Physics, Sri Venkateswara University, Tirupati, for the study of dynamical behaviour of the atmospheric boundary layer (ABL) phenomena over Tirupati. The infrasonic pressure variations have been recorded near sodar site using a microbarograph. Short-period waves/down-flow structures (rare phenomena) caused due to onset of drainage flow are reported. The short-period wave (fluctuations) is usually associated with either convective plume activity or ground-based inversions in the evening transition hours. It is inferred that these short-period waves are caused due to the onset of nocturnal drainage flows under convection/thermal inversion of variable depth

Investigation of gravity waves in the atmospheric boundary layer using sodar and microbarograph

247-259Presence of irregularities and irregular motions in the atmospheric boundary layer (ABL) have been detected and studied by a variety of techniques, including sodars and microbarographs. The infrasonic pressure variations have been recorded at Tirupati using a microbarograph. Wave motions associated with temperature inversions in ABL are studied using an acoustic sounder and a microbarograph. Two-year investigation of waves and wave perturbations in low-level inversions in the atmosphere over Tirupati valley region are reported. A detailed study on wave motions in terms of diurnal variation, seasonal variation, occurrence percentage and amplitude of the wave motion associated with different structures in ABL is made. Simultaneous study of the nature of waves in the atmosphere is made using echosonde and microbarograph data. Gravity waves are mostly observed in this region during winter and premonsoon seasons due to temperature inversions and thunderstorms. In order to characterize the wave nature and to study the effect of their motions occurring mostly at nighttime stable conditions, cross-correlation and power spectral density technique have been applied