Hot QCD equations of state and relativistic heavy ion collisions

We study two recently proposed equations of state (EOS) which are obtained from high temperature QCD, and show how they can be adapted to use them for making predictions for relativistic heavy ion collisions. The method involves extracting equilibrium distribution functions for quarks and gluons from the EOS, which in turn will allow a determination of the transport and other bulk properties of the quark gluon plasma. Simultaneously, the method also yields a quasi particle description of interacting quarks and gluons. The first EOS is perturbative in the QCD coupling constant and has contributions of $O(g^5)$. The second EOS is an improvement over the first, with contributions upto $O(g^6 ln(\frac{1}{g}))$; it incorporates the nonperturbative hard thermal contributions. The interaction effects are shown to be captured entirely by the effective chemical potentials for the gluons and the quarks, in both the cases. The chemical potential is seen to be highly sensitive to the EOS. As an application, we determine the screening lengths which are, indeed the most important diagnostics for QGP. The screening lengths are seen to behave drastically differently depending on the EOS considered., and yield, therefore, a way to distinguish the two equations of state in heavy ion collisions.Comment: 11 pages, fifteen figures, two column, accepted for publication in PR

Identification of Top Performing Economies

Using seven indicators of the economic performance of 187 countries, the paper identifies the top 50 performers during the decades of 1981-90 and 1991-2000. Five of these indicators are the trend rates of growth over a decade in imports, FDI, capital formation, per capita income and forex reserves. Average inflation rate and HDI are the remaining indicators. Comparison of top performers of the 1980s and the 1990s suggest that high performance in inflation and HDI are the precondition for consistency of high overall performance over time. The paper also examines the interrelationship among the indicators over time.

Internet connectivity for mobile Ad Hoc networks

Ad hoc networking allows portable devices to establish communication independent of a central infrastructure. However, the fact that there is no central infrastructure and that the devices can move randomly gives rise to various kind of problems, such as routing and security. In this thesis the problem of routing is considered. There are several ad hoc routing protocols, such as AODV, DSR, OLSR and ZRP, that propose solutions for routing within a mobile ad hoc network. However, since there is an interest in communication between not only mobile devices in an ad hoc network, but also between a mobile device in an ad hoc network and a fixed device in a fixed network (e.g. the Internet), the ad hoc routing protocols need to be modified. In this thesis the ad hoc routing protocol AODV is used and modified to examine the interconnection between a mobile adhoc network and the Internet. For this purpose Network Simulator 2, ns2, has been used. Moreover, three proposed approaches for gateway discovery are implemented and investigated. The goal of the thesis project is twofold: • To modify the source code of AODV in accordance with the Internet draft\Global connectivity for IPv6 Mobile Ad Hoc Networks " which presents a solution where AODV is used to provide Internet access to mobile nodes. • To implement and compare di®erent approaches for gateway discovery. In this thesis, three di®erent type of gateway discovery have been taken: • The proactive gateway discovery is initiated by the gateway itself. The gateway periodically broadcasts a gateway advertisement message which is transmitted after expiration of the gateways timer. The time between two consecutive advertisements must be chosen with care so that the network is not °ooded unnecessarily. All mobile devices residing in the gateways transmission range receive the advertisement and update information about gateway. After receiving advertisement, a mobile device just forward it broadcast it again. This process goes on within entire MANET. • In reactive gateway discovery a mobile device of MANET connects by gateway only when it is needed. For that the mobile device broadcasts request message to the ALL MANET GW MULTICAST address (the IP address for the group of all gateways in a mobile ad hoc network). Thus, only the gateways are addressed by this message and only they process it. Intermediate mobile nodes that receive the message just forward it by broadcasting it again up to gateway. • To minimize the disadvantages of proactive and reactive gateway discovery, the two approaches can be combined. This results is a hybrid gateway discovery. For mobile devices in a certain range around a gateway, proactive gateway discovery is used. Mobile devices residing outside this range use reactive gateway discovery to obtain information about the gateway. In comparing theses di®erent gateway discovery, three matrices are used. These are packet delivery ratio,average end-to-end delay and overhead. In case of proactive gateway discovery and hybrid gateway discovery, value of packet delivery ratio is larger than reactive gateway discovery. In case of proactive gateway discovery and hybrid gateway discovery, value of end to end delay is less than reactive gateway discovery. The overhead of proactive gateway discovery is greater than other two gateway discovery As for the average end-to-end delay, the proactive and hybrid methods perform slightly better than the reactive method. Concerning the routing overhead, when the advertisement interval is short the reactive method generates much less overhead than the proactive method, which in turn generates much less overhead than the hybrid method

Petrology and tectonic development of supracrustal sequence of Kerala Khondalite Belt, Southern India

The granulite terrain of southern India, of which the Kerala Khondalite belt (KKB) is a part, is unique in exposing crustal sections with arrested charnockite growth in different stages of transformation and in varied lithological association. The KKB with rocks of surficial origin and incipient charnockite development, poses several problems relating to the tectonics of burial of vast area and mechanisms involved in expelling initial H2O (causes of dryness) for granulite facies metamorphism. It is possible to infer the following sequence of events based on the field and laboratory studies: (1) derivation of protoliths of KKB from granitic uplands and deposition in fault bounded basin (cratonic rift); (2) subhorizontal deep burial of sediments; (3) intense deformation of infra and supracrustal rocks; (4) early granulite facies metamorphism predating F sub 2 - loss of primary structure in sediments and formation of charnockites from amphibole bearing gneisses and khondalites from pelites; (5) migmatisation and deformation of metasediments and gneisses; (6) second event of charnockite formation probably aided by internal CO2 build-up; and (7) isothermal uplift, entrapment of late CO2 and mixed CO2-H2O fluids, formation of second generation cordierites and cordierite symplectites