17 research outputs found
Sea Breeze Detection with Acoustic Radar
176-181A preliminary study on sea breeze fronts has been made at Visakhapatnam using a monostatic acoustic radar situated in the University campus, very near to the sea shore. During the summer of 1980 sea breeze was almost a daily phenomenon at Visakhapatnam, and was usually seen as a well marked distinct change in the character of the acoustic radar records. The increased thermal turbulence associated with the transfer of heat from the surface into the layer of marine air produced enhanced sound scattering up to the height of 150 m. The sea breeze often created an elevated layer usually in the height range 200-500 m. Acoustic backscatter records obtained in May 1980, when the sea breeze was strongest, are presented and discussed in the light of the prevailing weather conditions and previous experimental studies reported from this station
Simultaneous Study of Sea Breeze with Two Monostatic Acoustic Sounders
136-142Sea breeze at Visakhapatnamis influenced by the unique combination of topographic meteorological and oceanographic features To characterize the main features of sea breeze as it penetrates inland, two monostatic acoustic sounders have been operated simultaneousliy in May 1983 one at the University site about 1 km away from the coastline and other at the airport meteorological observatory about 11 km west inland. From the sounder records of the two sites and the supporting meteorological data it has been observed that the sea breeze at the two locations differs considerably in respect of its onset, duration, depth and thermal turbulence distribution. This marked variability is attributed to the peculiar orography of the locale
Acoustic Sounder Study of Sea Breeze in Southwest Monsoon Season
199-204Acoustic sounder echo patterns obtained at Visakhapatnam during periods of sea breeze in the month of July 1980 (monsoon month) are presented and discussed in the light of the prevailing weather conditions and surface meteorological data obtained from the antenna site. Sea breeze occurrence in July is occasional. unlike daily occurrence in summer, because of the dominant gradient flow from west to east due to the prevailing southwest monsoon. A large increase in the intensity and height of backscattered echoes was observed at the onset of sea breeze indicating the thermally inhomogeneous and turbulent nature of the air just behind the moving sea breeze front. The increase in the depth of the sea breeze as shown by the acoustic records was mirrored in hygrograrns
Acoustic Sounding of Coastal Boundary Layer
21-28The acoustic sounder data obtained during the period June 1980-May 1981 have been analyzed with special reference to sea breeze. Simultaneous measurements of sea breeze using pilot balloon ascents and acoustic sounder were made on eight days in May 1981. A reasonably good agreement has been obtained between the acoustic sounder estimation of the depth of the sea breeze and the height of the onshore flow as deduced from hourly balloon ascents. The height variations of the elevated layer on the sounder record were also reflected in the flow patterns. The development of the elevated layer associated with the sea breeze circulation was delayed due to the limited vertical extent of sea breeze in the first few hours after the onset. The alternation or land and sea breeze more than once during a day in the observational period was partly due to the oscillatory behaviour of a trough of low pressure inland. The monthly charts prepared for the 12 months showed a definite seasonal variation in the diurnal behaviour of the coastal boundary layer at Visakhapatnam
Seasonal Variation of Coastal Meteorological Phenomena as Revealed by Acoustic Sounder
57-60A climatology of the boundary layer of the atmosphere at Visakhapatnam is compiled using the acoustic sounder data collected for a period of 3 yr from May 1980 to April 1983. The meteorological phenomena as inferred from the facsimile records are classified into 13 categories and then analyzed for percentage period of occurrence of each category in each month. It is found that the complex meteorological processes in coastal zones have a significant seasonal dependence
The EXPERIMENTAL STUDY ON INTERMITTENT TURNING OF ALUMINUM METAL MATRIX COMPOSITES USING K10 GRADE CARBIDE INSERTS
Metal matrix composites containing fly ash as reinforcement are primarily preferred because these materials possess lower density and higher strength to weight ratio. While turning Aluminum fly ash composites, presence of hard ceramic particles in the fly ash leads to the failure of the cutting tool. However the presence of the hard ceramic particulates in the composites induces hetrogeneous structure which causes chipping of the cutting tool during intermittent turning application. Selection of optimal cutting conditions for a given machining process is utmost important to enhance the tool life during intermittent turning operation. Thus the research work was aimed at the experimental investigation of the tool life during intermittent turning of Al6061 composites containing 0% to 15% of fly ash. The experiments were carried out following ISO3685 standards. Tungsten carbide inserts of grade K10 and CGGN120304 style inserts were the turning tools. The cutting speed selected was 150m/min, 300m/min, 450m/min, 600m/min and 750m/min, feed of 0.08 mm/revolution, 0.12mm/revolution, 0.16mm/revolution and radial depth of 1.2 mm. The experimental results revealed that the performance of K10 grade carbide insert found better when composites machined below 600 m/min cutting speed and feed of 0.08 mm/revolution irrespective of percentage fly ash
Convenient and Scalable Synthesis of 2,3-Dihydroquinazolin-4(1<i>H</i>)-one Derivatives and Their Anticancer Activities
<div><p></p><p>An efficient and mild InBr<sub>3</sub>-catalyzed approach to synthesize 2,3-dihydroquinazolin-4(1<i>H</i>)-one derivatives (<b>3a–3aa</b>) has been developed. Notably, all the products were isolated by recrystallization and the reaction is accessible on a gram scale. Moreover, the reactions only require 10–60 min. All the synthesized compounds were evaluated for their in vitro anticancer activity against four human cancer cell lines.</p></div
Synthesis of novel triazole functionalized pyridine derivatives as potential antimicrobial and anti-biofilm agents
1361-1375A series of novel 1-substituted (1H-1,2,3-triazole-4-yl) methoxy functionalized pyridine derivatives 5 and 6 have been prepared starting from 2(1H) pyridone 1 via selective O-propargylation followed by reaction with diverse substituted azides under Sharpless conditions. All the compounds 5 and 6 have been screened for antimicrobial activity, minimum bactericidal concentration and biofilm inhibition activity. Compounds 5d, 5l and 5s which showed promising activity specifically towards Staphylococcus aureus MTCC 96 and Staphylococcus aureus MLS-16 MTCC 2940 have been identified. Further, in silico docking studies have been carried out on the inhibition of dehydrosqualene synthase enzyme of S. aureus. This is a key enzyme in the biosynthesis of staphyloxanthin, a virulence factor for S. aureus. Further, on screening for antioxidant activity, the compounds 5l, 5q and 5n showed promising activity