Generic conditions for stable hybrid stars

We study the mass-radius curve of hybrid stars, assuming a single first-order phase transition between nuclear and quark matter, with a sharp interface between the quark matter core and nuclear matter mantle. We use a generic parameterization of the quark matter equation of state, which has a constant, i.e. density-independent, speed of sound ("CSS"). We argue that this parameterization provides a framework for comparison and empirical testing of models of quark matter. We obtain the phase diagram of possible forms of the hybrid star mass-radius relation, where the control parameters are the transition pressure, energy density discontinuity, and the quark matter speed of sound. We find that this diagram is sensitive to the quark matter parameters but fairly insensitive to details of the nuclear matter equation of state. We calculate the maximum hybrid star mass as a function of the parameters of the quark matter EoS, and find that there are reasonable values of those parameters that give rise to hybrid stars with mass above $2\,M_\odot$.Comment: 11 pages, 8 figures. Changes to nomenclature, references adde

Countering contagion: Does China's experience offer a blueprint?

China did not succumb to the Asian crisis of 1997-99, despite two apparent sources of vulnerability: a weak financial system and increased export competition from the Asian crisis economies. This article argues that both sources of vulnerability were more apparent than real. China's experience (especially its use of capital controls) does not offer a blueprint for other countries, because other countries would not want to replicate China's inefficient, non-market-oriented financial system.Banks and banking - China ; Economic conditions - China ; China

An architecture for object-oriented intelligent control of power systems in space

A control system for autonomous distribution and control of electrical power during space missions is being developed. This system should free the astronauts from localizing faults and reconfiguring loads if problems with the power distribution and generation components occur. The control system uses an object-oriented simulation model of the power system and first principle knowledge to detect, identify, and isolate faults. Each power system component is represented as a separate object with knowledge of its normal behavior. The reasoning process takes place at three different levels of abstraction: the Physical Component Model (PCM) level, the Electrical Equivalent Model (EEM) level, and the Functional System Model (FSM) level, with the PCM the lowest level of abstraction and the FSM the highest. At the EEM level the power system components are reasoned about as their electrical equivalents, e.g, a resistive load is thought of as a resistor. However, at the PCM level detailed knowledge about the component's specific characteristics is taken into account. The FSM level models the system at the subsystem level, a level appropriate for reconfiguration and scheduling. The control system operates in two modes, a reactive and a proactive mode, simultaneously. In the reactive mode the control system receives measurement data from the power system and compares these values with values determined through simulation to detect the existence of a fault. The nature of the fault is then identified through a model-based reasoning process using mainly the EEM. Compound component models are constructed at the EEM level and used in the fault identification process. In the proactive mode the reasoning takes place at the PCM level. Individual components determine their future health status using a physical model and measured historical data. In case changes in the health status seem imminent the component warns the control system about its impending failure. The fault isolation process uses the FSM level for its reasoning base

Economic Analysis of Transaction Cost on Kolaramma Tank Watershed in Eastern Dry Zone of Karnataka

The transaction cost incurred on the Kolaramma tank watershed in the Kolar district of Karnataka, with a geographical area of 6,570 hectares and covering 26 catchments has been found to be Rs 78,89,210. The decomposition of this transaction cost into information, contractual and enforcement costs has revealed that enforcement cost amounted to a vast share of 82.0 per cent, followed by contractual cost (13.6%) and information cost (4.4%) in the total transaction cost. Considering the overall transaction cost, the investment on information and contractual cost has been quite less. These need to be increased by economizing on the administrative expenses of the implementing agency. Any additional investment on information and contractual cost would greatly benefit the actual beneficiaries in the watershed.Resource /Energy Economics and Policy,

Frequency Dependence of Double Band Electroluminophors

In the present paper an attempt has been made to study the emission characteristics of the two peaks, blue and green of a (ZnS:Cu) double band electroluminophor, particularly the frequency effect. As regards voltage, both the peaks are found to behave in the usual way but the frequency relations give rise to somewhat new results With a rise in applied field frequency, the green band suffers a peak shift towards lower wavelength side, whereas the blue one is always shouldered and is little affected as far as peak position is concerned. The light output is observed to fall down at higher frequencies instead of showing a constant intensity of emission