1,506 research outputs found
Impact of Land Tenure System in Watershed Development Programmes in the Meghalaya State, North-East India
Besides the analysis of technical and ecological viability, knowledge of the existing land tenure systems is an essential pre-requisite for the success of watershed projects and policy reforms required for their effective implementation. Using descriptive analysis, Lorenz curve and Gini concentration ratio (GCR), this study has explained the relationship between the existing land tenure systems and the prospects for the success of watershed projects in the Meghalaya State, North-East India. The study has revealed that the Umsiang watershed project having community ownership system of tenure produced more positive changes in the landuse pattern after the project implementation than the Maweit watershed project practising individual ownership system. The area under jhum cultivation in the Umsiang watershed decreased significantly due to transformation of jhum sloppy lands into permanent contour cultivation. The area under horticulture plantations particularly fruit crops increased by 2118 per cent; afforested and aquaculture areas also increased by 296 and 2480 per cent, respectively after the project. The area under jhum cultivation in the Maweit watershed decreased only marginally (by 2%) and the area under permanent contour cultivation was negligible after the project. The absence of ownership rights to the tenants in the Maweit watershed has resulted in little incentive for the adoption of long-term development measures. The annual average income per household increased to Rs 40,227 (36% increase) in the Umsiang watershed and to Rs 36,313 (19% increase) in the Maweit watershed after the project. The offfarm income went up by 49 per cent in the Umsiang watershed and 38 per cent in the Maweit watershed. The watershed projects under the Community ownership system of land tenure would be more successful in increasing farm income and employment opportunities. The income inequality also decreased in the Umsiang watershed after the project as shown by Lorenz curve and GCR. But the gap between the rich and the poor in the Maweit watershed increased after the project. The study has clearly indicated that land tenure system is an important factor in the implementation of watershed projects successfully. Effective land reform policy would be essential for the successful implementation of watershed development programmes.Agricultural and Food Policy,
Single CFTA Based Current-Mode Universal Biquad Filter
This paper introduces a new current-mode (CM) universal biquad filter structure with optimum number of active and passive elements. In the design, the proposed circuit uses a single active element namely, current follower trans-conductance amplifier (CFTA) and two grounded capacitors as passive elements. The main feature of the proposed circuit is that it can realize all five standard filtering functions such as low pass (LP), band pass (BP), high pass (HP), band stop (BS) and all pass (AP) responses across an explicit high impedance output terminal through the appropriate selection of three inputs. In addition, the same circuit is also capable to simultaneously realize three filtering functions (LP, BP and HP) by the use of single current input signal. Moreover, the proposed structure is suited for low voltage, low power operations and offers the feature of electronic tunability of pole-frequency and quality factor. Further to extend the utility of the proposed circuit block higher order current-mode filters are also realized through direct cascading. A detailed non-ideal and parasitic study is also included. The performance of the circuits has been examined using standard 0.25 μ m CMOS parameters from TSMC
Experimental study of the erosion of Ar/H2 plasma facing carbon surfaces: optical emission spectroscopy, mass spectrometry and spectroscopic ellipsometry measurements
Carbon materials could be used for divertor plates in the ITER fusion device. Numerous studies (experimental or modeling) have been undertaken to better understand the chemical processes involved in carbon erosion by hydrogen atoms or ions. These works have been performed for several kinds of carbon layers and different hydrogen (or deuterium) ion fluxes. Results of an experimental study on carbon-material erosion under hydrogen bombardment will be presented. Optical emission spectroscopy and mass spectrometry have been employed to determine the presence of excited and stable molecules that are formed under these conditions. Ex situ spectroscopic ellipsometry has been used to calculate the erosion rate. In order to determine this erosion rate during plasma exposure and with a better precision, preliminary results on in situ spectroscopic ellipsometry will be presented
Trajectory and stability of Lagrangian point in the Sun-Earth system
This paper describes design of the trajectory and analysis of the stability
of collinear point in the Sun-Earth system. The modified restricted three
body problem with additional gravitational potential from the belt is used as
the model for the Sun-Earth system. The effect of radiation pressure of the Sun
and oblate shape of the Earth are considered. The point is asymptotically
stable upto a specific value of time correspond to each set of values of
parameters and initial conditions. The results obtained from this study would
be applicable to locate a satellite, a telescope or a space station around the
point .Comment: Accepted for publication in Astrophysics & Space Scienc
An ARPES view on the high-Tc problem: phonons vs spin-fluctuations
We review the search for a mediator of high-Tc superconductivity focusing on
ARPES experiment. In case of HTSC cuprates, we summarize and discuss a
consistent view of electronic interactions that provides natural explanation of
both the origin of the pseudogap state and the mechanism for high temperature
superconductivity. Within this scenario, the spin-fluctuations play a decisive
role in formation of the fermionic excitation spectrum in the normal state and
are sufficient to explain the high transition temperatures to the
superconducting state while the pseudogap phenomenon is a consequence of a
Peierls-type intrinsic instability of electronic system to formation of an
incommensurate density wave. On the other hand, a similar analysis being
applied to the iron pnictides reveals especially strong electron-phonon
coupling that suggests important role of phonons for high-Tc superconductivity
in pnictides.Comment: A summary of the ARPES part of the Research Unit FOR538,
http://for538.wmi.badw.d
Destruction of diagonal and off-diagonal long range order by disorder in two-dimensional hard core boson systems
We use quantum Monte Carlo simulations to study the effect of disorder, in
the form of a disordered chemical potential, on the phase diagram of the hard
core bosonic Hubbard model in two dimensions. We find numerical evidence that
in two dimensions, no matter how weak the disorder, it will always destroy the
long range density wave order (checkerboard solid) present at half filling and
strong nearest neighbor repulsion and replace it with a bose glass phase. We
study the properties of this glassy phase including the superfluid density,
energy gaps and the full Green's function. We also study the possibility of
other localized phases at weak nearest neighbor repulsion, i.e. Anderson
localization. We find that such a phase does not truly exist: The disorder must
exceed a threshold before the bosons (at weak nn repulsion) are localized. The
phase diagram for hard core bosons with disorder cannot be obtained easily from
the soft core phase diagram discussed in the literature.Comment: 7 pages, 10 eps figures include
How Should Diverse Stakeholder Interests Shape Evaluations of Complex Water Resources Systems Robustness When Confronting Deeply Uncertain Changes?
Robustness analysis can support the design and operation of large-scale water infrastructure projects confronting deeply uncertain futures. However, diverse actors, contextual specificities, sectoral interests, and risk attitudes make it difficult to identify an appropriate robustness metric to rank decision alternatives under deep uncertainty. Here, we clarify how methodological choices affect robustness evaluation using the multi-actor, multi-sector Inchampalli-Nagarjuna Sagar water transfer megaproject in Southern India. We compare a suite of water transfer strategies discovered using evolutionary multi-objective direct policy search (EMODPS), a strategy proposed by regional authorities and the status quo of no water transfer. We stress-test these strategies across scenarios that capture climatic and socioeconomic uncertainties and rank them using robustness metrics representing sectoral perspectives and priorities of different actors with varying risk attitudes. Results show a considerable impact of metric choices on robustness rankings of strategies, with compromise solution discovered via EMODPS as robust. The no-transfer strategy results in the worst water supply robustness with an average volumetric deficit of 17% of total historical demands but emerges as a robust alternative for 6 out of 12 combinations of actor-sectors with high risk aversion. Also, changes in the amplitude of the Indian Summer Monsoon is identified as the most important uncertain factor determining the failure of strategies. Our findings highlight that the selection of robust solutions should be guided by an understanding of how assumed risk attitudes shape stakeholders' perceptions of vulnerabilities. These findings are generalizable to large infrastructure projects with diverse stakeholders and multisectoral impacts
Comparison of superconductivity in Sr_2RuO_4 and copper oxides
To compare the superconductivity in strongly correlated electron systems with
the antiferromagnetic fluctuations in the copper oxides and with the
ferromagnetic fluctuations in Sr_2RuO_4 a t-J-I model is proposed. The
antiferromagnetic coupling J results in the superconducting state of
d_{x^2-y^2} symmetry and the ferromagnetic coupling constant I results in the
spin-triplet p-type state. The difference in the gap anisotropies provides the
large difference in T_c values, for the typical values of the coupling
constants: T_c of order of 1K for the ruthenate and T_c of order of 100K for
the cuprates.Comment: 4 pages, RevTEX, 3 figs. Submitted to Phys. Rev. Let
Searching for the Slater Transition in the Pyrochlore CdOsO with Infrared Spectroscopy
Infrared reflectance measurements were made on the single crystal pyrochlore
CdOsO in order to examine the transformations of the
electronic structure and crystal lattice across the boundary of the metal
insulator transition at . All predicted IR active phonons are
observed in the conductivity over all temperatures and the oscillator strength
is found to be temperature independent. These results indicate that charge
ordering plays only a minor role in the MIT and that the transition is strictly
electronic in nature. The conductivity shows the clear opening of a gap with
. The gap opens continuously, with a temperature
dependence similar to that of BCS superconductors, and the gap edge having a
distinct dependence. All of these
observables support the suggestion of a Slater transition in CdOsO.Comment: 4 pages, 4 figure
First-principles Calculation of the Formation Energy in MgO-CaO Solid Solutions
The electronic structure and total energy were calculated for ordered and
disordered MgO-CaO solid solutions within the multiple scattering theory in
real space and the local density approximation. Based on the dependence of the
total energy on the unit cell volume the equilibrium lattice parameter and
formation energy were determined for different solution compositions. The
formation energy of the solid solutions is found to be positive that is in
agreement with the experimental phase diagram, which shows a miscibility gap.Comment: 11 pages, 3 figure
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