Enhancing productivity of water under variable climate

Crop productionMaizeClimateRainFamersDecision making

Enhancing productivity of water under variable climate

Irrigated farmingProductivityCrop productionMaizeSimulation modelsClimateForecasting

Bibliografia

Bhaskara Ra

Bibliografia

Bhaskara Ra

Magnetic and electron transport properties of the rare-earth cobaltates, La0.7-xLnxCa0.3CoO3 (Ln = Pr, Nd, Gd and Dy) : A case of phase separation

Magnetic and electrical properties of four series of rare earth cobaltates of the formula La0.7-xLnxCa0.3CoO3 with Ln = Pr, Nd, Gd and Dy have been investigated. Compositions close to x = 0.0 contain large ferromagnetic clusters or domains, and show Brillouin-like behaviour of the field-cooled DC magnetization data with fairly high ferromagnetic Tc values, besides low electrical resistivities with near-zero temperature coefficients. The zero-field-cooled data generally show a non-monotonic behaviour with a peak at a temperatures slightly lower than Tc. The near x = 0.0 compositions show a prominent peak corresponding to the Tc in the AC-susceptibility data. The ferromagnetic Tc varies linearly with x or the average radius of the A-site cations, (rA). With increase in x or decrease in (rA), the magnetization value at any given temperature decreases markedly and the AC-susceptibility measurements show a prominent transition arising from small magnetic clusters with some characteristics of a spin-glass. Electrical resistivity increases with increase in x, showed a significant increase around a critical value of x or (rA), at which composition the small clusters also begin to dominate. These properties can be understood in terms of a phase separation scenario wherein large magnetic clusters give way to smaller ones with increase in x, with both types of clusters being present in certain compositions. The changes in magnetic and electrical properties occur parallely since the large ferromagnetic clusters are hole-rich and the small clusters are hole-poor. Variable-range hopping seems to occur at low temperatures in these cobaltates.Comment: 23 pages including figure

Remote Sensing of Sea Surface Temperature

A thorough knowledge of the distribution of sea surface temperature over large areas is important in the geophysical and marine sciences. This enables one to understand certain atmospheric and oceanic processes, in the detection and monitoring of ocean currents, upwelling zones and other circulation systems. Unfortunately, a true and complete picture of the sea surface temperature distribution has not been available due to observational difficulties. Sea surface temperature charts that are available now are based on commercial ship reports and on data from research cruises. Comprehensive survey of this feature by means of sensors carried in aircraft, ships or any other similar platforms would be time-consuming and is frequently impractical. An earth satellite in a near-polar orbit can best provide useful information about the sea surface temperature. After the launch of several TIROS and Nimbus satellites containing different radiometers, it has been shown that it is possible to measure the sea surface temperature distributions under relatively clear sky conditions. The observed temperature distributions are very complex and difficult to interpret in the absence of any ground truth information. In the future every effort should be made to obtain sufficient concurrent surface observations in order to successfully compare and interpret the data

Evolution of constrained layer damping using a cellular automaton algorithm

Constrained layer damping (CLD) is a highly effective passive vibration control strategy if optimized adequately. Factors controlling CLD performance are well documented for the flexural modes of beams but not for more complicated mode shapes or structures. The current paper introduces an approach that is suitable for locating CLD on any type of structure. It follows the cellular automaton (CA) principle and relies on the use of finite element models to describe the vibration properties of the structure. The ability of the algorithm to reach the best solution is demonstrated by applying it to the bending and torsion modes of a plate. Configurations that give the most weight-efficient coverage for each type of mode are first obtained by adapting the existing 'optimum length' principle used for treated beams. Next, a CA algorithm is developed, which grows CLD patches one at a time on the surface of the plate according to a simple set of rules. The effectiveness of the algorithm is then assessed by comparing the generated configurations with the known optimum ones

Optimal Control of Quantum Dynamics : A New Theoretical Approach

A New theoretical formalism for the optimal quantum control has been presented. The approach stems from the consideration of describing the time-dependent quantum system in terms of the real physical observables, viz., the probability density rho(x,t) and the quantum current j(x,t) which is well documented in the Bohm's hydrodynamical formulation of quantum mechanics. The approach has been applied for manipulating the vibrational motion of HBr in its ground electronic state under an external electric field.Comment: 4 figure

ESR evidence for disordered magnetic phase from ultra-small carbon nanotubes embedded in zeolite nanochannels

A multi-frequency electron spin resonance (ESR) study provides evidence for the occurrence of low temperature ferromagnetic/spin-glass behavior in aligned arrays of sub-nanometer single walled carbon nanotubes confined in zeolite nano-channels, owing to sp2-type non-bonding carbon associated localized states with density of ~3 x 1019 /g. Features related to the much anticipated conduction ESR are not detected. In the paramagnetic phase, the ESR linewidth is found to be weakly dependent on microwave frequency.Comment: Accepted to be published in EuroPhysics Letter

Indian edible oyster

In India pioneering attempts were made by James Hornell in 1910 in developing Oyster culture in the erstwhile Madras State. Scientific investigations were undertaken during early 70's by the Central Marine Fisheries Research Institute, at Tuticorin. The Institute has conducted R & D programmes on all aspects of Oyster farming during the last two decades, culminating in a wealth of informations on the technology of Oyster farming. The Brochure outlines various aspects of the technology of farming of the Indian Edible Oyster or the Indian Backwater Oyster Crasaostrea madrasensis (Preston} including information on biology, ecology and economics of Oyster farming