Experimental evidence for vibrational resonance and enhanced signal transmission in Chua's circuit

We consider a single Chua's circuit and a system of a unidirectionally coupled n-Chua's circuits driven by a biharmonic signal with two widely different frequencies \omega and \Omega, where \Omega >> \omega. We show experimental evidence for vibrational resonance in the single Chua's circuit and undamped signal propagation of a low-frequency signal in the system of n-coupled Chua's circuits where only the first circuit is driven by the biharmonic signal. In the single circuit, we illustrate the mechanism of vibrational resonance and the influence of the biharmonic signal parameters on the resonance. In the n(= 75)-coupled Chua's circuits enhanced propagation of low-frequency signal is found to occur for a wide range of values of the amplitude of the high-frequency input signal and coupling parameter. The response amplitude of the ith circuit increases with i and attains a saturation. Moreover, the unidirectional coupling is found to act as a low-pass filter.Comment: 15 pages, 12 figures, Accepted for Publication in International Journal of Bifurcation and Chao

Design and Performance Validation of Vapour Absorption Solar Air Conditioning System

The Solar based absorption systems are used for the reduction of power load that is caused because of the utilization of the compressors. There have been different absorption sets that are tried for space cooling applications by bringing in different solar based heat inputs. The NH3 � H2O based absorption system need a working temperature of 120�C to 150�C, and requires concentrators with tracking and attracting higher qualities, however NH3 � H2O vapour absorption systems can operate at lower temperatures and can utilize FPC or ETC solar water heating frameworks as generators. In the near future, this will bring in low cost and low maintenance. The single effect 1 KW, NH3 � H2O absorption system with evacuated tube solar collector is attempted in this research work. The testing of the system and comparison of COPs with standard vapour absorption Solar Air Conditioning system are done

An Electron Microscope Study of Biomineralisation for Geotechnical Engineering Purposes

XJTL

SCREENING OF PHYTOCHEMICAL, ANTIOXIDANT ACTIVITY AND ANTI-BACTERIAL ACTIVITY OF MARINE SEAWEEDS

Objective: Phytochemical is naturally present in the seaweeds which biologically play a significant role. The intention of this study was designed to screen the phytochemical constituents and antimicrobial potential of selected seaweed collected from Rameshwaram and Tuticorin Southern coast of India.Methods: The present study investigated the presence of phytochemical constituents and also total phenol, total carbohydrate and total protein quantity of the brown seaweed. Dictyopteris delicatula, Padina gymnospora, Acanthophora spicifera, Portieria hornemannii and Ulva faciata were extracted with solvents having different polarities like methanol, ethanol, chloroform and water and screened for the phytochemical constituents, total phenol, total carbohydrate, total protein and DPPH with standard procedure. The antibacterial activities of the seaweeds were examined by agar well diffusion method.Results: Among the five seaweeds, U. faciata showed the maximum number of active constituents in the methanol extract likewise P. gymnospora was found to have a number of diligent compounds in ethanol extract. A. spicifera showed minimum compounds in ethanol as well as chloroform extract. Moreover A. spicifera, P. hornemannii have shown the superior quantity of protein and carbohydrate when compared to other species. The scavenging activity of methanol extracts at 5 mg/ml concentration P. hornemannii shows 18.2% and A. spicifera possess 17.1%. In the antibacterial activity, methanol extracts of all the seaweed showed a potential inhibitory activity against B. cereus and P. aeruginosa compared to other pathogens.Conclusion: The crude extract of seaweed manifest preferable antimicrobial and antioxidant activities, hence in the future, it would be good if it is further taken for treatment of human diseases or as new antimicrobial agents to replace synthetic antimicrobial agents

Relationship of pulse pressure variation and stroke volume variation with cardiac output changes during mechanical ventilation in ASA 2 & 3 patients, undergoing major spine surgeries in prone position

OBJECTIVES OF THE STUDY: To determine the correlation between Pulse Pressure Variation and Stroke Volume Variation with Cardiac Index in ASA 2 & 3 patients, during mechanical ventilation in patients undergoing major spine prone surgeries. METHODS OF THE STUDY: We conducted an observational study in 30 patients who underwent major spine surgeries in prone position, in ASA class 2 and 3 patients with either long-term Diabetes or Hypertension with possible altered Arterial elastance. All the patients were given 10ml/kg of crystalloid before proning. Baseline values of Cardiac Index (CI), Pulse Pressure Variation (PPV) and Stroke Volume Variation (SVV) were noted. The changes in PPV and SVV during (>20%) change in CI was noted. Similar measurements were taken after correcting CI. Data was analysed using the Spearman's Rank Correlation Coefficient between PPV and SVV and between PPV and Cardiac Index. RESULTS AND CONCLUSION: Out of 29 patients, 26 patients were ASA class 2 and three were ASA 3 patients. We obtained a consistent statistically significant strong correlation between PPV and SVV (correlation coefficient of (r=0.87) and (P<0.001). We found a consistent weakly negative correlation between PPV and CI with [r= (-0.21)] and [P (>0.3)]. Though there was a strong Clinical correlation between CI and PPV, there was only a weak statistical correlation. We conclude that PPV and SVV correlate with each other even in patients with altered Arterial elastance in the prone position

Larvicidal and repellent activity of tetradecanoic acid against Aedes aegypti (Linn.) and Culex quinquefasciatus (Say.) (Diptera:Culicidae)

AbstractObjectiveTo investigate the larvicidal and repellent efficacy of tetradecanoic acid against Aedes aegypti (Ae. aegypti) L. and Culex quinquefasciatus (Cx. quinquefasciatus) Say (Diptera: Culicidae).MethodsLarvicidal efficacy of tetradecanoic acid was tested at various concentrations against the early third instar larvae of Ae. aegypti and Cx. quinquefasciatus. The repellent activity was determined against two mosquito species at three concentrations viz., 1.0,2.5 and 5.0 ppm under the laboratory conditions.ResultsThe tetradecanoic acid was found to be more effective against Cx. quinquefasciatus than Ae. aegypti larvae. The LC50 values were 14.08 ppm and 25.10 ppm, respectively. Tetradecanoic acid showed lesser repellency against Ae. aegypti and Cx. quinquefasciatus. The highest repellency was observed in higher concentration of 5.0 mg/cm2 provided 100% protection up to 60 and 90 min against Ae. aegypti and Cx. quinquefasciatus respectively.ConclusionsFrom the results it can be concluded the tetradecanoic acid is a potential for controlling Cx. quinquefasciatus and Ae. aegypti mosquitoes