736 research outputs found

    Criticality of tuning in athermal phase transitions

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    We experimentally address the importance of tuning in athermal phase transitions, which are triggered only by a slowly varying external field acting as tuning parameter. Using higher order statistics of fluctuations, a singular critical instability is detected for the first time in spite of an apparent universal self-similar kinetics over a broad range of driving force. The results as well as the experimental technique are likely to be of significance to many slowly driven non-equilibrium systems from geophysics to material science which display avalanche dynamics.Comment: 5 pages, 4 figure

    Volume Integral Theorem for Exotic Matter

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    We answer an important question in general relativity about the volume integral theorem for exotic matter by suggesting an exact integral quantifier for matter violating Averaged Null Energy Condition (ANEC). It is checked against some well known static, spherically symmetric traversable wormhole solutions of general relativity with a sign reversed kinetic term minimally coupled scalar field. The improved quantifier is consistent with the principle that traversable wormholes can be supported by arbitrarily small quantities of exotic matter.Comment: 7 page

    Development of cost-effective phasor measurement unit for wide area monitoring system applications

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    Sustained growth in the demand with unprecedented investments in the transmission infrastructure resulted in narrow operational margins for power system operators across the globe. As a result, power networks are operating near to stability limits. This has demanded the electrical utilities to explore new avenues for control and protection of wide area systems. Present supervisory control and data acquisition/energy management systems (SCADA/EMS) can only facilitate steady state model of the network, whereas synchrophasor measurements with GPS time stamp from wide area can provide dynamic view of power grid that enables supervision, and protection of power network and allow the operator to take necessary control/remedial measures in the new regime of grid operations. Construction of phasor measurement unit (PMU) that provide synchrophasors for the assessment of system state is widely accepted as an essential component for the successful execution of wide area monitoring system (WAMS) applications. Commercial PMUs comes with many constraints such as cost, proprietary hardware designs and software. All these constraints have limited the deployment of PMUs at high voltage transmission systems alone. This paper addresses the issues by developing a cost-effective PMU with open-source hardware, which can be easily modified as per the requirements of the applications. The proposed device is tested with IEEE standards

    Signature of Martensite transformation on conductivity noise in thin films of NiTi shape memory alloys

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    Slow time-dependent fluctuations, or noise, in the electrical resistance of dc magnetron sputtered thin films of Nickel Titanium shape memory alloys have been measured. Even in equilibrium, the noise was several orders of magnitude larger than that of simple diffusive metallic films, and was found to be non-monotonic around the martensitic transformation regime. The results are discussed in terms of dynamics of structural defects, which also lay foundation to a new noise-based characterization scheme of martensite transformation.Comment: 4 pages, 3 figure

    Nutritional status and socioeconomic empowerment of fisherwomen in the coastal ecosystem of Andhra Pradesh, Karnataka, Kerala and Tamil Nadu, India

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    This study was carried out in the coastal areas of Andhra Pradesh, Karnataka, Kerala and Tamil Nadu. From these states, 13 districts and 28 villages were selected. A total of 5,744 households were covered. Cereal consumption was highest in Andhra Pradesh followed by Kerala, Karnataka and Tamil Nadu. Pulse consumption was high in Kerala when compared to other states. The overall energy intake of the fisherwomen was 1,827 kcal/day; protein intake was 50.6 gm/day; carbohydrate intake was 343.5 gm/day; and fat intake was 27 gm/day. The mean intake of micronutrients was less than the recommended dietary allowance. The mean body mass index was 21.3. The nutritional status of the women was: 49% normal; 17% low normal; 10.5% mildly malnourished; 4% moderately malnourished; and 2.9% severely malnourished. About 11.5% of the fisherwomen were overweight and 4.6% were obese. A subsample of 915 women was clinically observed: 34.8% were diagnosed with angular stomatitis; 31 % with cheelosis; 42.8% with bleeding gums; and 44.2% with dry skin. Some 72% of the women were anemic. An assessment ofthe socioeconomic status indicated that very few households (15.4%) maintained livestock for income generation. About 60% of the fisherwomen carried out post-harvest activities to earn income. Food expenditure comprised 60.7% of the earned income contribvting to the major share of the spending. Debt servicing was a serious problem faced by 44.9% of the respondents who had procured loans mostly from non-institutional sources

    Semiclassical and Quantum Field Theoretic Bounds for Traversable Lorentzian Stringy Wormholes

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    A lower bound on the size of a Lorentzian wormhole can be obtained by semiclassically introducing the Planck cut-off on the magnitude of tidal forces (Horowitz-Ross constraint). Also, an upper bound is provided by the quantum field theoretic constraint in the form of the Ford-Roman Quantum Inequality for massless minimally coupled scalar fields. To date, however, exact static solutions belonging to this scalar field theory have not been worked out to verify these bounds. To fill this gap, we examine the wormhole features of two examples from the Einstein frame description of the vacuum low energy string theory in four dimensions which is the same as the minimally coupled scalar field theory. Analyses in this paper support the conclusion of Ford and Roman that wormholes in this theory can have sizes that are indeed only a few order of magnitudes larger than the Planck scale. It is shown that the two types of bounds are also compatible. In the process, we point out a "wormhole" analog of naked black holes.Comment: 15 page

    Socio-economic status of fisherwomen

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    In India, women constitute about 50 per cent of the population and comprise one third of the labour force. Women account for 32.5 per cent of the total work force of 121.63 million (1993-94) and the figure is still increasing day by day. Among the different sectors of the Indian economy where women contribute significantly, fishery sector is an important one. Out of the 5.4 million active fishers in India, 3.8 million (70.37%) are fishermen and 1.6 million (29.63%) are fisherwomen

    Anthropometric measurements of fisherwomen and preschool children

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    Anthropometry is one of the methods used in nutritional assessment. Nutritional anthropometry can be defined as measurement of variation of the physical dimensions and the gross composition of the human body at different age levels and degrees of malnutritio

    Role of women in Fisheries: An Overview

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    Women playa key role in the development of fisheries sector in addition to their role of sole household managers in most fisher families
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