Phytochemical Studies of Phyllanthus debilis

K.S.Chandrashekar,D.Satyanarayana,A.B.Joshi,E.V.S.Subrahmanyam 한국생약학회 2004 Natural Product Sciences Vol.10 No.3

Two Lignans Phyllanthin and Hypophyllanthin, and a steroid b-sitosterol has been isolated from the leaves of Phyllanthus debilis and their structures were established by spectral analysis and direct comparison with authentic samples. This is the first report of occurrence of these compound from P.debilis.

Novel room tempreature grown carbon based cathodes for field emission using diamond nano-particle seeding technique

B. S. Satyanarayana,A. Hiraki 한국표면공학회 2001 한국표면공학회지 Vol.34 No.5

In Vitro Clonal Propagation of Chlorophytum Borivilianum

B N. Maruthi Prasad,B N. Satyanarayana,Nagarajappa Adivappar,B G. Hanumantharaya 한국원예학회 2006 한국원예학회 기타간행물 Vol.- No.-

An Efficient Machine Learning Model for Clinical Support to Predict Heart Disease

Rao, B.Vara Prasada,Reddy, B.Satyanarayana,Padmaja, I. Naga,Kumar, K. Ashok International Journal of Computer ScienceNetwork S 2022 International journal of computer science and netw Vol.22 No.6

Early detection can help prevent heart disease, which is one of the most common reasons for death. This paper provides a clinical support model for predicting cardiac disease. The model is built using two publicly available data sets. The admissibility and application of the the model are justified by a sequence of tests. Implementation of the model and testing are also discussed

Effect of Aging and Oxidation on Strain Hardening Behaviour of a Nickel-free High Nitrogen Austenitic Stainless Steel

B. Karthik,R. Veerababu,D. V. V. Satyanarayana 대한금속·재료학회 2016 METALS AND MATERIALS International Vol.22 No.3

Effect of aging and oxidation on strain hardening behaviour of a nickel-free high nitrogen austenitic stainless steel has been investigated using room temperature tensile tests and TEM. The alloy in both oxidised and unoxidised conditions exhibits a transition in flow behaviour that can be described best by the Ludwigson flow relationship as evident from the lowest values of the sum of residual squares, χ 2 , of the fit. The transition in macroscopic flow behaviour with strain has been correlated to change in deformation mechanism from planar slip in the low strain regime (LSR) to deformation twinning and slip in the high strain regime (HSR) in solution treated (ST) condition of the alloy. However, the LSR of the alloy aged for longer times (>100 h) is characterized by the formation of dislocation tangles, while the HSR is marked by the formation of well-defined finer dislocation cell structure. This difference in deformation sub-structures in low and high strain regimes between ST and long term aged samples has been correlated to the change in stacking fault energy due to the precipitation of Cr2N and σ-phases. Further, the alloy in ST condition exhibits the highest strain hardening rate, which then progressively decreases with aging time.

Isolation and Characterization of Indole Alkaloids from the Flowers of Ervatamia Coronaria (Syn: Taberaemontana divaricata)

A.B.Joshi,D.Satyanarayana,K.S.Chandrashekar,E.V.S.Subrahmanyam 한국생약학회 2004 Natural Product Sciences Vol.10 No.3

From the flowers of Ervatamia coronaria four indole alkaloids have been isolated and characterized as harmine, heyneanine, voacristine and apparicine with the help of various spectral data. The alkaloids Harmine and Heyneanine are reported first time from the flowers of Ervatamia coronaria.

Cavitation studies on axi-symmetric underwater body with pumpjet propulsor in cavitation tunnel

Suryanarayana, Ch.,Satyanarayana, B.,Ramji, K.,Rao, M. Nageswara The Society of Naval Architects of Korea 2010 International Journal of Naval Architecture and Oc Vol.2 No.4

A pumpjet propulsor (PJP) was designed for an underwater body (UWB) with axi-symmetric configuration. Its performance was predicted through CFD study and models were manufactured. The propulsor design was evaluated for its propulsion characteristics through model tests conducted in a Wind Tunnel (WT). In the concluding part of the study, evaluation of the cavitation performance of the pumpjet was undertaken in a cavitation tunnel (CT). In order to assess the cavitation free operation speeds and depths of the body, cavitation tests of the PJP were carried out in behind condition to determine the inception cavitation numbers for rotor, stator and cowl. The model test results obtained were corrected for full scale Reynolds number and subsequently analyzed for cavitation inception speeds at different operating depths. From model tests it was also found that the cavitation inception of the rotor takes place on the tip face side at higher advance ratios and cavitation shifts towards the suction side as the RPS increases whereas the stator and cowl are free from cavitation.

Experimental evaluation of pumpjet propulsor for an axi-symmetric body in wind tunnel

Ch. Suryanarayana,B. Satyanarayana,K. Ramji,A Saiju 대한조선학회 2010 International Journal of Naval Architecture and Oc Vol.2 No.1

Design of a Pump-Jet Propulsor (PJP) was undertaken for an underwater body with axi-symmetric configuration using axial flow compressor design techniques supported by CFD analysis for performance prediction. Experimental evaluation of the PJP was carried out through experiments in Wind Tunnel Facility (WTF) using momentum defect principle for propulsive performance prior to proceeding with extensive experimental evaluation in towing tank and cavitation tunnel. Experiments were particularly conducted with respect to Self Propulsion Point (SPP), residual torque and thrust characteristics over a range of vehicle advance ratio in order to ascertain whether sufficient thrust is developed at the design condition with least possible imbalance torque left out due to residual swirl in the slip stream. Pumpjet and body models were developed for the propulsion tests using Aluminium alloy forged material. Tests were conducted from 0 m/s to 30 m/s at four rotational speeds of the PJP. SPP was determined confirming the thrust development capability of PJP. Estimation of residual torque was carried out at SPP corresponding to speeds of 15, 20 and 25 m/s to examine the effectiveness of the stator. Estimation of thrust and residual torque was also carried out at wind speeds 0 and 6 m/s for PJP RPMs corresponding to self propulsion tests to study the propulsion characteristics during the launch of the vehicle in water where advance ratios are close to Zero. These results are essential to assess the thrust performance at very low advance ratios to accelerate the body and to control the body during initial stages. This technique has turned out to be very useful and economical method for quick assessment of overall performance of the propulsor and generation of exhaustive fluid dynamic data to validate CFD techniques employed. Design of a Pump-Jet Propulsor (PJP) was undertaken for an underwater body with axi-symmetric configuration using axial flow compressor design techniques supported by CFD analysis for performance prediction. Experimental evaluation of the PJP was carried out through experiments in Wind Tunnel Facility (WTF) using momentum defect principle for propulsive performance prior to proceeding with extensive experimental evaluation in towing tank and cavitation tunnel. Experiments were particularly conducted with respect to Self Propulsion Point (SPP), residual torque and thrust characteristics over a range of vehicle advance ratio in order to ascertain whether sufficient thrust is developed at the design condition with least possible imbalance torque left out due to residual swirl in the slip stream. Pumpjet and body models were developed for the propulsion tests using Aluminium alloy forged material. Tests were conducted from 0 m/s to 30 m/s at four rotational speeds of the PJP. SPP was determined confirming the thrust development capability of PJP. Estimation of residual torque was carried out at SPP corresponding to speeds of 15, 20 and 25 m/s to examine the effectiveness of the stator. Estimation of thrust and residual torque was also carried out at wind speeds 0 and 6 m/s for PJP RPMs corresponding to self propulsion tests to study the propulsion characteristics during the launch of the vehicle in water where advance ratios are close to Zero. These results are essential to assess the thrust performance at very low advance ratios to accelerate the body and to control the body during initial stages. This technique has turned out to be very useful and economical method for quick assessment of overall performance of the propulsor and generation of exhaustive fluid dynamic data to validate CFD techniques employed.

Performance evaluation of an underwater body and pumpjet by model testing in cavitation tunnel

Ch. Suryanarayana,B. Satyanarayana,K. Ramji 대한조선학회 2010 International Journal of Naval Architecture and Oc Vol.2 No.2

Experimental investigations were carried out on an Axi-symmetric Body Model fitted with Pump-jet Propulsor (PJP) in the Cavitation Tunnel at Naval Science and Technological Laboratory (NSTL). The tests were intended for evaluating the propulsion characteristics of the body and propulsor. The self propulsion point of the model for two configurations was determined after finding the corrections for tunnel blockage effects and differences in model length at zero trim. The results were found to match closely with the towing tank results. The rotor and stator torques also matched closely over full range of experiment. Further experiments were carried out on the body at 4.5º angle of trim to investigate the propulsive performance and assess the operational difficulties in the sea. The results indicated an increase in resistance and decrease in rotor thrust; but the balance of torques between the rotor and stator was undisturbed, causing no concern to vehicle roll. Experimental investigations were carried out on an Axi-symmetric Body Model fitted with Pump-jet Propulsor (PJP) in the Cavitation Tunnel at Naval Science and Technological Laboratory (NSTL). The tests were intended for evaluating the propulsion characteristics of the body and propulsor. The self propulsion point of the model for two configurations was determined after finding the corrections for tunnel blockage effects and differences in model length at zero trim. The results were found to match closely with the towing tank results. The rotor and stator torques also matched closely over full range of experiment. Further experiments were carried out on the body at 4.5º angle of trim to investigate the propulsive performance and assess the operational difficulties in the sea. The results indicated an increase in resistance and decrease in rotor thrust; but the balance of torques between the rotor and stator was undisturbed, causing no concern to vehicle roll.

Cavitation studies on axi-symmetric underwater body with pumpjet propulsor in cavitation tunnel

Ch. Suryanarayana,B. Satyanarayana,K. Ramji,M. Nageswara Rao 대한조선학회 2010 International Journal of Naval Architecture and Oc Vol.2 No.4

A pumpjet propulsor (PJP) was designed for an underwater body (UWB) with axi-symmetric configuration. Its performance was predicted through CFD study and models were manufactured. The propulsor design was evaluated for its propulsion characteristics through model tests conducted in a Wind Tunnel (WT). In the concluding part of the study, evaluation of the cavitation performance of the pumpjet was undertaken in a cavitation tunnel (CT). In order to assess the cavitation free operation speeds and depths of the body, cavitation tests of the PJP were carried out in behind condition to determine the inception cavitation numbers for rotor, stator and cowl. The model test results obtained were corrected for full scale Reynolds number and subsequently analyzed for cavitation inception speeds at different operating depths. From model tests it was also found that the cavitation inception of the rotor takes place on the tip face side at higher advance ratios and cavitation shifts towards the suction side as the RPS increases whereas the stator and cowl are free from cavitation.