COMPUTATIONAL STUDY OF THE EFFECT OF GEOMETRIC PARAMETERS ON THE PERFORMANCE OF SINGLE EXPANSION RAMP NOZZLE FLOWS

The present work deals with the computational study of the single expansion ramp nozzle (SERN) flows for the supersonic regime. Theoretical calculations are carried out for different geometries with certain assumptions. Based on the initial calculation and with the help of Method of Characteristics, nozzle configuration with similar axisymmetric convergent portion and distinct non-axisymmetric divergent portions are drafted. Commercial CFD software ANSYS 12 with Navier Stokes code is used for the computational studies. The study begins with a simple upper flat ramp at different angles with a very small lower cowl at fixed angles. The divergent section of a conventional three-dimensional nozzle is used as the upper ramp of the SERN. The study includes the variation of the ramp at different angles ranging from 16 deg. to 24 deg. with 2 deg. intervals, the cowl angle ranging from 0 deg. to 6 deg. with 2 deg. intervals and the length of the cowl varying from 0.2, 0.4, 0.6, 0.8 and 1.0 times the length of the ramp. The performance parameters like Thrust, Normal force and Mach Variation for these different contours are analyzed and compared. The various parameters used are nozzle length, cowl length, cowl angle, ramp-angle, and ramp length. The shape of the SERN is optimized for the design parameters. The grid sensitivity computational analysis is also performed before finalizing the grid for study

Experimental Investigation On Machining Performance of Ti6Al4V On Electro Discharge Machining Using Stationary and Rotary Electrode

Titanium alloys are commonly used in different industries due to its high strength and less in weight. Even though the machinability of titanium alloys is very less, due to its high strength, it becomes more useful in aerospace and medical industries. In this study, the performance of stationary and rotary copper electrodes on machining of Titanium alloy Ti-6Al-4V with Electro Discharge Machining (EDM). Material removal rate(MRR), tool ware rate(TWR) and surface roughness(SR) were analyzed with three controllable input parameters such as pulse on time (Ton), Peak Current(Ip) and Gap Voltage (V). The design of experiment chosen for the experimentation as the Box-Behnken response surface design method. The results are analysed using grey relational analysis(GRA) coupled with firefly algorithm. In both the case of stationary and rotary electrode, it was revealed that gap voltage is significant for overall grey relational grade. The machining performance of Titanium alloy Ti-6Al-4V in the case of rotary mode of electrode is quite better as compare to the stationary mode of operation

Experimental Investigation On Machining Performance of Ti6Al4V On Electro Discharge Machining Using Stationary and Rotary Electrode

Titanium alloys are commonly used in different industries due to its high strength and less in weight. Even though the machinability of titanium alloys is very less, due to its high strength, it becomes more useful in aerospace and medical industries. In this study, the performance of stationary and rotary copper electrodes on machining of Titanium alloy Ti-6Al-4V with Electro Discharge Machining (EDM). Material removal rate(MRR), tool ware rate(TWR) and surface roughness(SR) were analyzed with three controllable input parameters such as pulse on time (Ton), Peak Current(Ip) and Gap Voltage (V). The design of experiment chosen for the experimentation as the Box-Behnken response surface design method. The results are analysed using grey relational analysis(GRA) coupled with firefly algorithm. In both the case of stationary and rotary electrode, it was revealed that gap voltage is significant for overall grey relational grade. The machining performance of Titanium alloy Ti-6Al-4V in the case of rotary mode of electrode is quite better as compare to the stationary mode of operation

Phytochemical screening and evaluation of cytotoxic activity of Pandanus fascicularis L. (Fruits)

The present study was conducted to evaluate possible phytochemicals present, and cytoctoxic activity of extract of fruits of Pandanus fascicularis L. Phytochemical screening was carried out using the standard test methods of different chemical group. Evaluation of cytotoxic activity was done using the brine shrimp lethality bioassay. The aqueous, methanolic, ethanolic, ethyl acetate, pet ether and chloroform extracts show presence of maximum phytochemicals such as alkaloids, tannins, flavonoids, steroids, saponins, proteins, terpens, phenols, glycosides, carbohydrate in different fractions etc. During cytotoxicity test, the positive control groups showed nonlinear mortality rates at lower concentrations and linear rates at higher concentrations. The LC50 values of Chloroform extract was found 1.0636 µg/ml where the positive control vincristine sulphate showed LC50 at a concentration of 0.200µg/ml. Therefore, the plant extract possess potent cytotoxic effect

The Diversity Analysis of the Microbial Community in Wastewater by Amplified rDNA Restriction Analysis (ARDRA)ï€

AbstractActivated sludge, a common biological treatment method for both municipal and industrial waste water, represents a complex microbial community.  Due to intricate interactions within the microbial community, process control of waste water treatment plants can be difficult.  Population shifts within the microbial community may results from the changes in the plant operating conditions and cause sludge quality problems such as poor sludge settling, compaction and dewatering.  Monitoring of the microbial populations may help in the diagnosis and correction of such sludge problems. This study employed a PCR-based 16S rDNA, amplified rDNA restriction analysis (ARDRA) approach to characterize the microbial community structure in wastewater. Samples were collected from two wastewater treatment plants, in Jaipur City, India. Each PCR product was obtained by PCR with eubacteria 16S rDNA. After amplification, the 16S rDNA PCR products were digested with 4-base site specific restriction endonucleases. Restriction pattern was analyzed with four endonucleases (AluI, MspI, HhaI, and HaeIII). The result of the bacterial community analysis, by ARDRA revealed that the two wastewater treatment plants carry significantly different microbial population, whereas the diversity among the samples of same plant is not much. These results suggests that Amplified rDNA restriction analysis (ARDRA) is an extremely valuable tool for assessing the diversity from waste water treatment plants. Key words: ARDRA, Microbial community, Wastewater1Birla Inst of Scientific Research, Statue Circle, Jaipur, Rajasthan, India2Deptt of  Botany, University of Rajasthan, Jaipur, India---Please Cite This Article As: Shivani Chandra, Sivaramaiah Nalapeta, Sampat Nehra, Alok Kumar Varshney, Nupur Mathur, P C. Trivedi, Krishna Mohan Medicherla. 2010. The Diversity Analysis of the Microbial Community in Wastewater by Amplified rDNA Restriction Analysis (ARDRA). J. Ecobiotechnol. 2(4):51-55.Â

Distributed Consensus, Revisited

We provide a novel model to formalize a well-known algorithm, by Chandra and Toueg, that solves Consensus among asynchronous distributed processes in the presence of a particular class of failure detectors (Diamond S or, equivalently, Omega), under the hypothesis that only a minority of processes may crash. The model is defined as a global transition system that is unambigously generated by local transition rules. The model is syntax-free in that it does not refer to any form of programming language or pseudo code. We use our model to formally prove that the algorithm is correct

ILLUMINATING THE DARKEST GAMMA-RAY BURSTS WITH RADIO OBSERVATIONS

We present X-ray, optical, near-infrared (IR), and radio observations of gamma-ray bursts (GRBs) 110709B and 111215A, as well as optical and near-IR observations of their host galaxies. The combination of X-ray detections and deep optical/near-IR limits establish both bursts as "dark." Sub-arcsecond positions enabled by radio detections lead to robust host galaxy associations, with optical detections that indicate z ≾ 4 (110709B) and z ≈ 1.8-2.9 (111215A). We therefore conclude that both bursts are dark due to substantial rest-frame extinction. Using the radio and X-ray data for each burst we find that GRB 110709B requires A_V^(host) ≳ 5.3 mag and GRB 111215A requires A_V^(host) ≳ 8.5 mag (assuming z = 2). These are among the largest extinction values inferred for dark bursts to date. The two bursts also exhibit large neutral hydrogen column densities of N H, int ≳ 10^(22) cm^(–2) (z = 2) as inferred from their X-ray spectra, in agreement with the trend for dark GRBs. Moreover, the inferred values are in agreement with the Galactic A_V -N_H relation, unlike the bulk of the GRB population. Finally, we find that for both bursts the afterglow emission is best explained by a collimated outflow with a total beaming-corrected energy of E_γ + E_K ≈ (7-9) × 10^(51) erg (z = 2) expanding into a wind medium with a high density, Ṁ ≈ (6-20) x 10^(-5) M_☉ yr^(–1) (n ≈ 100-350 cm^(–3) at ≈ 10^(17) cm). While the energy release is typical of long GRBs, the inferred density may be indicative of larger mass-loss rates for GRB progenitors in dusty (and hence metal rich) environments. This study establishes the critical role of radio observations in demonstrating the origin and properties of dark GRBs. Observations with the JVLA and ALMA will provide a sample with sub-arcsecond positions and robust host associations that will help to shed light on obscured star formation and the role of metallicity in GRB progenitors

Butorphanol in Labour Analgesia

Introduction: Labour is the process where uterine contractions lead to expulsion of product of conception through the vagina into the outer world. Labour pain is one of the most severe pains which has ever been evaluated and its fear is one of the reasons women wouldn’t go for natural delivery. Delivery is a painful experience for all of the women except a few of them. The labor pain results from some physiological-psychological causes. Different pharmacological and non-pharmacological methods have been tried for pain relief in labour. The objective of this study is to see the effect of butorphanol injection in labour pain. Methods: It is a descriptive cross-sectional study conducted in B.P. Koirala institute of health sciences. We observed 200 pregnant women meeting the inclusion criteria and giving the informed consent who were on 1 mg butorphanol i.m. at the onset of active stage of labour every 4 hourly and on demand. Pain assessment was done by Numerical Pain analogue scale measured from 1 to 10. Fetal heart rate monitoring was done according to the hospital protocol. Caesarean section was performed for obstetrical indication. Neonatal outcome was evaluated by on duty pediatrician and APGAR score were noted at 1 and 5 min. Results: The pain scores in first, second, third, fourth hour were (8.83±0.773), (9.84±0.544), (9.94±0.338), (9.6±0.298) respectively, where 1st and 2nd hour is statistically significant. Conclusions: Butorphanol is an effective labour analgesia without significant adverse effects on women and the neonatal outcome

A Comparison of Solar Cycle Variations in the Equatorial Rotation Rates of the Sun's Subsurface, Surface, Corona, and Sunspot Groups

Using the Solar Optical Observing Network (SOON) sunspot-group data for the period 1985-2010, the variations in the annual mean equatorial-rotation rates of the sunspot groups are determined and compared with the known variations in the solar equatorial-rotation rates determined from the following data: i) the plasma rotation rates at 0.94Rsun, 0.95Rsun,...,1.0Rsun measured by Global Oscillation Network Group (GONG) during the period 1995-2010, ii) the data on the soft X-ray corona determined from Yohkoh/SXT full disk images for the years 1992-2001, iii) the data on small bright coronal structures (SBCS) which were traced in Solar and Heliospheric Observatory (SOHO)/EIT images during the period 1998-2006, and iv) the Mount Wilson Doppler-velocity measurements during the period 1986-2007. A large portion (up to approximate 30 deg latitude) of the mean differential-rotation profile of the sunspot groups lies between those of the internal differential-rotation rates at 0.94Rsun and 0.98Rsun.The variation in the yearly mean equatorial-rotation rate of the sunspot groups seems to be lagging that of the equatorial-rotation rate determined from the GONG measurements by one to two years.The amplitude of the latter is very small.The solar-cycle variation in the equatorial-rotation rate of the solar corona closely matches that determined from the sunspot-group data.The variation in the equatorial-rotation rate determined from the Mount Wilson Doppler-velocity data closely resembles the corresponding variation in the equatorial-rotation rate determined from the sunspot-group data that included the values of the abnormal angular motions (> 3 deg per day) of the sunspot groups. Implications of these results are pointed out.Comment: 22 pages, 10 figures, accepted by Solar Physic

Analytical and numerical investigation of escape rate for a noise driven bath

We consider a system-reservoir model where the reservoir is modulated by an external noise. Both the internal noise of the reservoir and the external noise are stationary, Gaussian and are characterized by arbitrary decaying correlation functions. Based on a relation between the dissipation of the system and the response function of the reservoir driven by external noise we numerically examine the model using a full bistable potential to show that one can recover the turn-over features of the usual Kramers' dynamics when the external noise modulates the reservoir rather than the system directly. We derive the generalized Kramers' rate for this nonequilibrium open system. The theoretical results are verified by numerical simulation.Comment: Revtex, 25 pages, 5 figures. To appear in Phys. Rev.