Time Delay Induced Death in Coupled Limit Cycle Oscillators

We investigate the dynamical behaviour of two limit cycle oscillators that interact with each other via time delayed coupling and find that time delay can lead to amplitude death of the oscillators even if they have the same frequency. We demonstrate that this novel regime of amplitude "death" also exists for large collections of coupled identical oscillators and provide quantitative measures of this death region in the parameter space of coupling strength and time delay. Its implication for certain biological and physical applications is also pointed out.Comment: 4 aps formatted revtex pages; 3 figures; to be published in Phys. Rev. Let

Experimental Evidence of Time Delay Induced Death in Coupled Limit Cycle Oscillators

Experimental observations of time delay induced amplitude death in a pair of coupled nonlinear electronic circuits that are individually capable of exhibiting limit cycle oscillations are described. In particular, the existence of multiply connected death islands in the parameter space of the coupling strength and the time delay parameter for coupled identical oscillators is established. The existence of such regions was predicted earlier on theoretical grounds in [Phys. Rev. Lett. 80, 5109 (1998); Physica 129D, 15 (1999)]. The experiments also reveal the occurrence of multiple frequency states, frequency suppression of oscillations with increased time delay and the onset of both in-phase and anti-phase collective oscillations.Comment: 4 aps formatted RevTeX pages; 6 figures; to appear in Phys. Rev. Let

Preparation of some 5,7-diarylcyclohexeno[3,4-d]-l-selena-2,3-diazolyl-6- spiro-5'-(2',3'-pyrazolidine / 2',3'-oxazolidine)-l ',4'-diones and 5,7-diarylcyclohexeno[3,4-d]-1-thia-2,3-diazolyl-6-spiro-5'(2',3'-pyrazolidine/2',3'-oxazolidine )-1',4'-diones

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Experimental observation of the amplitude death effect in two coupled nonlinear oscillators

The amplitude death phenomenon has been experimentally observed with a pair of thermo-optical oscillators linearly coupled by heat transfer. A parametric analysis has been done and compared with numerical simulations of a time delayed model. The role of the coupling strength is also discussed from experimental and numerical results

Growth performance and carcass characteristics of growing ram lambs fed sweet sorghum bagasse-based complete rations varying in roughage-to-concentrate ratios

Different roughage-to-concentrate ratios of sweet sorghum bagasse (SSB) (a by-product of the biofuel industry)-based complete diets were assessed. Twenty four growing Nellore × Deccani ram lambs aged about 3 months (average body wt., 10.62 ± 0.25 kg) were randomly allotted to four complete rations (CR) varying in roughage-to-concentrate ratios viz. 60:40 (CR-I), 50:50 (CR-II), 40:60 (CR-III) and 30:70(CR-IV) for a period of 180 days. The feed intake was comparable among the lambs fed different experimental complete diets. Average daily weight gain (in grams) was 77.31 ± 4.90, 81.76 ± 5.16, 85.83 ± 2.83 and 86.30 ± 3.25, and feed conversion ratio (in kilograms of feed per kilogram gain) averaged 11.42 ± 0.68, 10.57 ± 0.64, 10.17 ± 0.37 and 9.96 ± 0.38 in ram lambs fed CR-I, CR-II, CR-III and CR-IV rations, respectively. Statistically, differences in daily weight gain and feed conversion ratio among the lambs fed four experimental rations were not significant (P > 0.05). The cost per kilogram gain was significantly (P < 0.01) higher in ram lambs fed CR-IV and CR-III rations compared to CR-I ration, and it was comparable between CR-I and CR-II rations. Dressing percentage averaged 44.90 ± 0.15, 42.57 ± 0.72, 43.67 ± 0.16 and 44.42 ± 0.76 for the respective diets. No significant difference and trend was observed in preslaughter weight, empty body weight, carcass weights, dressing percentage, wholesale cuts and edible and non-edible portions of experimental animals. Similarly, no significant variation could be seen in bone and meat yield (in per cent) and their ratios in various wholesale cuts among the dietary treatments. The roughage-to-concentrate ratio did not affect the chemical composition of meat; however, the fat content of meat was linearly increased with increase in the proportion of concentrate in the diets. The results of the experiment indicated that SSB can be included at 60 % level in the complete diet for economical mutton production from growing Nellore × Deccani ram lambs

Development of Wood Apple Shell ( Feronia acidissima

A biosorbent was prepared by using wood apple shell (WAS) powder and studied its application for the removal of Cd(II) from aqueous solution by a batch method. The biosorbent was characterized by infrared spectroscopy, X-ray diffraction, scanning electron microscopy, and elemental analysis. WAS is principally made up of lignin and cellulose, containing functional groups such as alcoholic, ketonic, and carboxylic groups which can be involved in complexation reactions with Cd(II). The effect of experimental parameters like initial pH, contact time, metal ion concentration, and sorbent dose on adsorption was investigated. The optimum pH for biosorption of Cd(II) onto WAS was found to be pH 5.0 and the quantitative removal of Cd(II) ions was achieved in 30 min. The kinetic study showed that the biosorption process followed the pseudo-second-order rate. Experimental data were analyzed by Langmuir, Freundlich, and Dubinin-Radushkevich isotherm models. Desorption studies were carried out using HCl solution

Enhancement of pigeonpea productivity through adoption of drought mitigating strategies

Pigeonpea (Cajanus cajan (L.) Millspaugh) is an important drought tolerant legume crop in Indian rainfed agriculture. Though India accounts for nearly 90% of the world’s pigeonpea acreage (3.73 million ha) and production (3.07 million t), the productivity is lower at 707 kg/ha than the world average. The Morocco India Food Legumes Initiative in collaboration with the ICRISAT is aimed at improving the livelihood of small farmers to strengthen food and nutritional security through adoption of improved technologies. This paper is focused on developing and disseminating strategies to improve pigeonpea productivity in dryland regions which are characterized by erratic rainfall, frequent and prolonged dry spells and soil nutrient depletion. During 2013-16, demonstrations were conducted in 1200 farmers’ fields in Mahabubnagar district, Telangana, India, with an objective of enhancing the productivity of pigeonpea using three drought mitigating strategies: (i) adoption of short-duration cultivar PRG 176, a high-yielding and early-maturing pedigree selection of ICPL 88034 x ICPL 88039 with a duration of 130-135 days; (ii) foliar application of soluble fertilizer to maintain vegetative growth and ultimately improve pod filling; (iii) life saving irrigation at the rate of 20 mm with water harvested from farm ponds during mid season drought and prolonged dry spells. Adoption of PRG 176 resulted in an average yield of 1400 kg/ha compared to LRG 41 (1120 kg/ha). The yield improvement of 25% can largely be attributed to the good branching habit (8- 13 primary branches) and high flower to pod conversion ratio of PRG 176 under dryland conditions. Foliar application of multi-K during flowering and pod formation stages enhanced the yield to 1360 kg/ha compared to the yield of 1100 kg/ha obtained in fields without foliar spray. Life saving irrigation in PRG 176 during mid season dry spell which persisted for 17-21 days improved the yields by 20 % compared to the yield of 1200 kg/ha obtained in rainfed crop. In conclusion, the study demonstrated that the productivity of pigeonpea in dryland regions can be enhanced to an average 1560 kg/ha through an integrated drought mitigating approach by exploiting the short-duration and high-yielding potential of PRG 176, providing life saving irrigation during critical growth stages and foliar application of nutrients at flowering and pod formation stages

Spontaneous phase oscillation induced by inertia and time delay

We consider a system of coupled oscillators with finite inertia and time-delayed interaction, and investigate the interplay between inertia and delay both analytically and numerically. The phase velocity of the system is examined; revealed in numerical simulations is emergence of spontaneous phase oscillation without external driving, which turns out to be in good agreement with analytical results derived in the strong-coupling limit. Such self-oscillation is found to suppress synchronization and its frequency is observed to decrease with inertia and delay. We obtain the phase diagram, which displays oscillatory and stationary phases in the appropriate regions of the parameters.Comment: 5 pages, 6 figures, to pe published in PR

Sweet Sorghum: A Smart Crop to Meet the Demands of Food, Fodder, Fuel and Feed

At present, energy demand for transport in India is primarily met through non-renewable energy sources like fossil fuels. Being short in domestic production, India mainly depends on crude oil imports. In the near future oil imports are slated to rise further with no major breakthrough in domestic oil production. A compounding factor is the rise in the number of vehicles on the road, which has grown by 10 % each year between 2001 and 2006, and is expected to rise further. Against this backdrop, there is a renewed interest in energy augmentation through biofuel crops to meet the energy demand in the country. One such promising biofuel crop is sweet sorghum, whose sugar-rich stocks can be crushed to produce juice, then fermented into bio-ethanol, and used to make a blended fuel replacing conventional gasoline (Reddy et al. 2005). Sweet sorghum is a C4 plant with high photosynthetic efficiency. It produces a high biomass (up to 40-50 t ha-1) in a short time (4 months) under rain-fed conditions (Reddy, et al., 2005). One advantage of sweet sorghum compared to other crops is that using sweet sorghum for fuel does not reduce its contribution as food because the grain can be harvested for food, and the bagasse (the fiber left over after extraction of juice from sweet sorghum) that remains after the extraction of juice used for biofuel may be used for fodder (Nalini Kumari et al. 2011). Hence, sweet sorghum is a “smart” crop, which meets the triple requirements of food, fuel and fodde