Hot Isostatic Pressing Technology for Defence and Space Applications

Hot isostatic pressing (HIP) technology has been established for the development of AISI-304 stainless steel and nickel base superalloy Inconel 718 integral turbine rotors, for liquid propulsion engine of Prithvi missile, and cryoengine of geostationary satellite launch vehicle (GSLV), respectively. Before making the full size rotors, the structure – property relationships in hot isostatic pressed (HIPed) 304 stainless steel and superalloy 718 were established. The HIPed steel and superalloy have shown near 100 per cent theoretical density, homogeneous, and fine grained microstructure. Their mechanical properties were found to be in agreement with those specified for the integral turbine rotors and hence, development of full size near net shaped integral turbine rotors was undertaken. The HIPed steel rotors subjected to the static engine tests have shown a satisfactory performance, and therefore a large number of rotors could be produced to fulfill the requirement of target labs. The HIP technology for the integral turbine rotors was found to be cost effective (about 50 per cent) over the conventional fabrication method which involves forging, machining, and welding of blades to the disk. The processing, structure, and properties of the HIPed 304 stainless steel and superalloy 718 in relation to the performance of integral turbine rotors for missile and space vehicle applications are discussed in this paper.Defence Science Journal, 2012, 62(1), pp.73-80, DOI:http://dx.doi.org/10.14429/dsj.62.37

Unusual landings of Goat fishes by Trawl nets at Visakhapatnam

Unusually heavy quantities of goat fishes were landed by private trawlers off Visakhapatnam operated at a depth of 25-35 metres

Ultrastructural and molecular characterization of altered plastids in nuclear gene controlled yellow stripe mutant of Pennisetum americanum

The ultrastructural and molecular biological studies were conducted to elucidate the changes in the nuclear gene controlled plastid alterations in yellow stripe mutant of Pennisetum americanum. The plastids in yellow tissue were bound by a double membrane envelope and no internal thylakoid membrane differentiation, whereas plastid development was normal in the green tissue. The nuclear gene apparently influences the individual plastids as evidenced by the presence of heteroplastidic cells. Ribosomal RNAs were extracted from green and yellow seedlings with homozygous recessive and heterozygous genotypes. Plastid specific 23S and 16S rRNAs were absent in the yellow seedlings irrespective of the genotype. The presence of disorganized lamellar membranes in the rRNA/ribosome deficient plastids indicate that they are synthesized outside the plastid compartment. Restriction endonuclease analysis revealed no detectable differences in fragmentation pattern of the plastid DNAs from green and reverted green seedlings. This is consistent with the suggestion that the nuclear gene is not inducing any change in the plastid genome size and in the restriction enzyme recognition sites

Long Term Variations of Ionospheric Horizontal Drift and Anisotropy of E-region Irregularities at Waltair

The study of long term variation of drift and anisotropy parameters of E region irregularities is particularly important because of the fact that D1 method measures movements of ionization that corresponds with neutral air motion in this region and facilitates a comparison with other methods of measuring winds in this region. The study of horizontal movements of small scale ionospheric irregularities at Waltair (17.70 N; 83.30 E) using D1 technique was started as early as I.G.Y.period. In this paper we present the results of observations of the drift and anisotropy parameters of ionospheric irregularities during equinox season over a span of about 10 years from 1957 to 1966 covering both the I.G.Y.and I.Q.S.Y.periods.About 140 midday (10-14 hrs) E-region drift records taken on frequency of 2.4 MHz are selected for the present study. There is an overall increase observed in the velocity parameters Va, V and Vc with the increase of sunspot number. The structure size, a of the irregularities shows a negative variation with sunspot number, decreasing magnitude with increase in sunspot number. There seem to be seasonal variation in the long term variation of some of the drift parameters with respect to solar epoch at Waltair.           

Development of a perfect prognosis probabilistic model for prediction of lightning over south-east India

A prediction model based on the perfect prognosis method was developed to predict the probability of lightning and probable time of its occurrence over the south-east Indian region. In the perfect prognosis method, statistical relationships are established using past observed data. For real time applications, the predictors are derived from a numerical weather prediction model. In the present study, we have developed the statistical model based on Binary Logistic Regression technique. For developing the statistical model, 115 cases of lightning that occurred over the south-east Indian region during the period 2006–2009 were considered. The probability of lightning (yes or no) occurring during the 12-hour period 0900–2100 UTC over the region was considered as the predictand. The thermodynamic and dynamic variables derived from the NCEP Final Analysis were used as the predictors. A three-stage strategy based on Spearman Rank Correlation, Cumulative Probability Distribution and Principal Component Analysis was used to objectively select the model predictors from a pool of 61 potential predictors considered for the analysis. The final list of six predictors used in the model consists of the parameters representing atmospheric instability, total moisture content in the atmosphere, low level moisture convergence and lower tropospheric temperature advection. For the independent verifications, the probabilistic model was tested for 92 days during the months of May, June and August 2010. The six predictors were derived from the 24-h predictions using a high resolution Weather Research and Forecasting model initialized with 00 UTC conditions. During the independent period, the probabilistic model showed a probability of detection of 77% with a false alarm rate of 35%. The Brier Skill Score during the independent period was 0.233, suggesting that the prediction scheme is skillful in predicting the lightning probability over the south-east region with a reasonable accuracy

Forward Sweeping Method for Solving Radial Distribution Networks

ABSTRACT: Practical rural distribution feeders have failed to converge while using NR and FDLF methods. Therefore, a new load flow technique for radial distribution networks by using node and branch numbering scheme will be developed. In the forward sweep, the voltage at each downstream bus is then updated by the real and imaginary components of the calculated bus voltages. The procedure stops after the mismatch of the calculated and specified Voltages at the substation is less than a convergence tolerance. A Forward sweeping method for solving radial distribution networks will be implemented. Thus, computationally, the proposed method will be a very efficient and requires less computer memory storage as all data is stored in vector form. The load flow will be run in MATLAB for solving the equations

Inverse relationship between chitobiase and transglycosylation activities of chitinase-D from Serratia proteamaculans revealed by mutational and biophysical analyses

Serratia proteamaculans chitinase-D (SpChiD) has a unique combination of hydrolytic and transglycosylation (TG) activities. The TG activity of SpChiD can be used for large-scale production of chito-oligosaccharides (CHOS). The multiple activities (hydrolytic and/or chitobiase activities and TG) of SpChiD appear to be strongly influenced by the substrate-binding cleft. Here, we report the unique property of SpChiD substrate-binding cleft, wherein, the residues Tyr28, Val35 and Thr36 control chitobiase activity and the residues Trp160 and Trp290 are crucial for TG activity. Mutants with reduced (V35G and T36G/F) or no (SpChiDΔ30–42 and Y28A) chitobiase activity produced higher amounts of the quantifiable even-chain TG product with degree of polymerization (DP)-6, indicating that the chitobiase and TG activities are inversely related. In addition to its unprecedented catalytic properties, unlike other chitinases, the single modular SpChiD showed dual unfolding transitions. Ligand-induced thermal stability studies with the catalytically inactive mutant of SpChiD (E153A) showed that the transition temperature increased upon binding of CHOS with DP2–6. Isothermal titration calorimetry experiments revealed the exceptionally high binding affinities for E153A to CHOS with DP2–6. These observations strongly support that the architecture of SpChiD substrate-binding cleft adopted to control chitobiase and TG activities, in addition to usual chitinase-mediated hydrolysis

DEVELOPMENT AND VALIDATION OF A NEW AND STABILITY INDICATING LC METHOD FOR ANALYSIS OF PINAVERIUM BROMIDE IN BULK DRUG AND PHARMA- CEUTICAL DOSAGE FORM

ABSTRACT A simple, rapid, and stability indicating reverse phase high performance liquid chromatographic assay method was developed for pinaverium bromide in the presence of its degradation products generated from decomposition studies.LC separation was achieved isocratic mode on a Zorbax SB C8 (4.6x250) mm, 5 µm column using mobile phase containing solution A (0.1% ortho phosphoric acid) with solution B (acetonitrile) (30:70) (v/v) at flow rate 1.0 ml/min. The UV detector was operated at 245 nm and temperature was 25˚C. The retention time was 4.84 min and linearity was observed in the concentration range of 20-150µg/ml with correlation coefficient of 0.9999. The percentage relative standard deviation in accuracy and precision studies was found to be less than 2%. The method was successfully validated as per International Conference on Harmonization (ICH) guidelines. pinaverium bromide undergoes degradation under acidic, basic, oxidation, dry heat and photolytic conditions, degradation impurities did not interfere with the retention time of pinaverium bromide, and assay method is thus stability indicating

Marine Fish Calendar. 2. Visakhapatnam

Gear wise landing details of the fish species in the important families (e.g. Clupeidae,Scombridae, Sciaenidae, etc.), groups (e.g. sardines,mackerel, croakers, etc.) in the Vishakapatnam landing centre during 1981-1986 was provided in the article