1,424 research outputs found
Watershed development: A solution to water shortages in semi-arid India or part of the problem?
There have been dramatic changes in the hydrology of many of the dry areas of South India in recent years as a result of increased groundwater-based irrigation, watershed development and land use change. Although intensive development of water resources has brought about huge benefits, its very success has thrown up new challenges. Demand and competition for water has increased to the extent that — in some areas — current levels of annual water use are so high that, in all but the wettest years, annual water use approximates towards annual replenishment of surface and ground water resources. In these areas, it is clear that the emphasis should switch from development to the management of water resources to ensure that water is allocated to activities with the highest economic and social value. Although current watershed development programmes bring a range of benefits, they may also change the temporal and spatial pattern of water availability and use. This can result in significant negative trade-offs such as more unreliable domestic water supplies in ‘downstream’ areas, particularly during low rainfall or drought years. As part of the Karnataka Watershed Development Project (KAWAD), a water resource audit assessed the status of water resources in the project watersheds and identified resource management practices that should be promoted by the project. This paper summarises the audit’s findings and recommendations, the main lessons learned and progress to date in implementing recommendations. For comparison, findings and recommendations from a water audit in southern Andhra Pradesh are also summarised.Resource /Energy Economics and Policy,
Simulation of mirror inversion of quantum states in an XY spin chain using NMR
We report an experimental quantum simulation of unitary dynamics of an XY
spin chain with pre-engineered couplings. Using this simulation, we demonstrate
the mirror inversion of quantum states, proposed by Albanese et al. [Phys. Rev.
Lett. 93, 230502 (2004)]. The experiment is performed with a 5-qubit dipolar
coupled spin system using nuclear magnetic resonance techniques. To perform
quantum simulation we make use of the recently proposed unitary operator
decomposition algorithm of Ajoy et al. [Phys. Rev. A 85, 030303 (2012)] along
with numerical pulse optimization techniques. Further, using mirror inversion,
we demonstrate that entangled states can be transferred from one end of the
chain to the other end. The simulations are implemented with high experimental
fidelity, which implies that these kind of simulations may be possible in
larger systems.Comment: 9 pages, 6 figure
Violation of Entropic Leggett-Garg Inequality in Nuclear Spins
We report an experimental study of recently formulated entropic Leggett-Garg
inequality (ELGI) by Usha Devi et al. (arXiv: 1208.4491v2 (2012)). This
inequality places a bound on the statistical measurement outcomes of dynamical
observables describing a macrorealistic system. Such a bound is not necessarily
obeyed by quantum systems, and therefore provides an important way to
distinguish quantumness from classical behavior. Here we study ELGI using a
two-qubit nuclear magnetic resonance system. To perform the noninvasive
measurements required for the ELGI study, we prepare the system qubit in a
maximally mixed state as well as use the `ideal negative result measurement'
procedure with the help of an ancilla qubit. The experimental results show a
clear violation of ELGI by over four standard deviations. These results agree
with the predictions of quantum theory. The violation of ELGI is attributed to
the fact that certain joint probabilities are not legitimate in the quantum
scenario, in the sense they do not reproduce all the marginal probabilities.
Using a three-qubit system, we experimentally demonstrate that three-time joint
probabilities do not reproduce certain two-time marginal probabilities.Comment: 5 pages, 5 figures, 1 page supplementar
Bending of Composite Plates-I
The problems of bending of aelotropic incompressible composite circular blocks into elliposidal shell have been studied following the method of Seth, et al. and a particular case has been obtained
Development of a creep data base management system for engineering materials
A fully menu driven creep data base management system has been developed for various high temperature materials using the client /server (C/S) architecture with Sybase system. 10 as backend and power builder 4.0 as an inter-face. The relational data base constitutes of various classes of materials, their heat treatment, prior history and the related creep properties at different test condit-ions, in addition to the source process route and chemical composition details.Top-down approach has been adopted in designing the entity-relationship (E-R) model. The creep data is organized into the third normal form, and the
entire system is divided into manageable modules. Coding for the system is done using Transact-SQL for data defin- ition, manipulation and control operations, and power script language for application development. This article briefly outlines the formulation of data base design, and the implemented E-R model, in addition , to the prese-ntation of various screen formats used for data entry and retrieval modules
Love Wave Propagation in Poro elasticity
It is observed that on similar reasons as in classical theory of elasticity, SH wave propagation in a semi infinite poroelastic body is not possible and is possible when there is a layer of another poro elastic medium over it i.e., Love waves. Two particular cases are considered in one of which phase velocity can be determined for a given wave length. In the same case, equation for phase velocity is of the same form as that of the classical theory of Elasticity
First report on observation of abnormal creep in a Zr-2.5wt.%Nb alloy at low stresses
Low-stress creep behaviour of a two-phase Zr-2.5%Nb alloy, differently heat treated, has been investigated using helical test specimens. The phase diagram of the α (hcp) + β (bcc) alloy is characterized by the monotectoid reaction at 893 ± 10 K: β1 → (α + β2) where β1 (Zr-20Nb) and β2 (Zr-80Nb) have widely differing compositions. At the creep testing temperature, 818 K, which is close to but below the monotectoid temperature, the creep rate for samples with the equilibrium α + β2 structure has been found to be considerably higher, over an order of magnitude, than that in samples with the metastable α + β1 structure. Microstructural changes accompanying the markedly enhanced creep rate for the α + β2 structure at stresses as low as 1-4 MPa have been explained in terms of the relative stability of the β1 and the β2 phases during the creep process. An attempt has been made to elicit the likely mechanism underlying the observed enhancement of creep rate and the changes in morphology, composition and volume fraction of the β phase
Stacking faults in double hexagonal close-packed crystals
Possible deviations in the regular ....ABACA.... sequence of stacking (0004) close-packed planes in the double hexagonal close-packed (d.h.c.p.) structure have been considered. Six intrinsic and one extrinsic type stacking faults have been suggested. The schemes of stacking sequences have been usefully considered in terms of the configurational symbols suggested by Jagodzinski. Extending the Hirth and Lothe procedure, estimates of theoretical fault energies are given in terms of the number of pairs of planes of separation N which are not in the shceme of perfect structure sequence. Relative fault energies have been arrived at reckoning only the first and second nearest neighbour interactions for three ideal situations: (a) the transformation energy of d.h.c.p. structure to either f.c.c. or h.c.p. structure is the same; (b) d.h.c.p. ⇌ f.c.c. transformation occurs; and (c) d.h.c.p. ⇌ h.c.p. transformation occurs
DSP Based Sensorless Control Of A BLDC Motor With Direct Back EMF Detection Method.
This paper proposes a scheme for sensorless control of brushless dc (BLDC) motor by a direct back EMF detection method
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