Incompressible Turbulence as Nonlocal Field Theory

It is well known that incompressible turbulence is nonlocal in real space because sound speed is infinite in incompressible fluids. The equation in Fourier space indicates that it is nonlocal in Fourier space as well. Contrast this with Burgers equation which is local in real space. Note that the sound speed in Burgers equation is zero. In our presentation we will contrast these two equations using nonlocal field theory. Energy spectrum and renormalized parameters will be discussed.Comment: 7 pages; Talk presented in Conference on "Perspectives in Nonlinear Dynamics (PNLD 2004)" held in Chennai, 200

Qubit(s) transfer in helical spin chains

Qubit(s) transfer through a helical chain is studied. We consider the transfer of a single state and Bell states across a multiferroic spin chain and the possibility of an electric field control of the fidelity of the single state and the Bell pairs. We analyze pure and imperfect multiferroic spin chains. A scheme for an efficient transfer of spin states through a multiferroic channel relies on kicking by appropriate electric field pulses at regular interval. This electric field pulse sequence undermines the effect of impurity on the fidelity and improves the state transfer through the helical chain.Comment: 7 pages, 10 figure

Strategies for Improving Indian Railways’ Market Share of Port Based Coal Traffic: A Diagnostic Study

India is a vast country. After its independence in 1947, it steadily lost its position in international trade. With the beginning of economic liberalization in 1991, it has taken new initiatives in integrating itself with the world economy. Import restrictions have been removed for many commodities. One of the major impacts of liberalization has been on infrastructure: railways, roadways, ports and airports. Significant changes have also taken place in the composition of imported and exported commodities. Due to these changes, new challenges are being faced on the infrastructure front. One of the challenges is to rectify the mismatch of available infrastructure at ports where a modal change of commodities that are either imported or exported takes place. This paper examines such issues with a specific focus on improving infrastructure required for integration of railways and ports. This is achieved by focusing on coal which is a commodity that (i) brings significant revenues to Indian Railways, and (ii) is witnessing increasing imports. In this diagnostic study, we discuss the problems faced by Indian Railways and identify ways to increase its market share of coal movement between ports and the hinterland.

The aromatic amino acid hydroxylase genes AAH1 and AAH2 in Toxoplasma gondii contribute to transmission in the cat

The Toxoplasma gondii genome contains two aromatic amino acid hydroxylase genes, AAH1 and AAH2 encode proteins that produce L-DOPA, which can serve as a precursor of catecholamine neurotransmitters. It has been suggested that this pathway elevates host dopamine levels thus making infected rodents less fearful of their definitive Felidae hosts. However, L-DOPA is also a structural precursor of melanins, secondary quinones, and dityrosine protein crosslinks, which are produced by many species. For example, dityrosine crosslinks are abundant in the oocyst walls of Eimeria and T. gondii, although their structural role has not been demonstrated, Here, we investigated the biology of AAH knockout parasites in the sexual reproductive cycle within cats. We found that ablation of the AAH genes resulted in reduced infection in the cat, lower oocyst yields, and decreased rates of sporulation. Our findings suggest that the AAH genes play a predominant role during infection in the gut of the definitive feline host

Efficient absolute aspect determination of a balloon borne far infrared telescope using a solid state optical photometer

The observational and operational efficiency of the TIFR 1 meter balloon borne far infrared telescope has been improved by incorporating a multielement solid state optical photometer (SSOP) at the Cassegrain focus of the telescope. The SSOP is based on a 1-D linear photo diode array (PDA). The online and offline processing schemes of the PDA signals which have been developed, lead to improvement in the determination of absolute telescope aspect ($\sim$ 0\farcm8), which is very crucial for carrying out the observations as well as offline analysis. The SSOP and its performance during a recent balloon flight are presented here.Comment: To appear in the February 2000 issue of the PAS

Local shell-to-shell energy transfer via nonlocal Interactions in fluid turbulence

In this paper we analytically compute the strength of nonlinear interactions in a triad, and the energy exchanges between wavenumber shells in incompressible fluid turbulence. The computation has been done using first-order perturbative field theory. In three dimension, magnitude of triad interactions is large for nonlocal triads, and small for local triads. However, the shell-to-shell energy transfer rate is found to be local and forward. This result is due to the fact that the nonlocal triads occupy much less Fourier space volume than the local ones. The analytical results on three-dimensional shell-to-shell energy transfer match with their numerical counterparts. In two-dimensional turbulence, the energy transfer rates to the near-by shells are forward, but to the distant shells are backward; the cumulative effect is an inverse cascade of energy.Comment: 10 pages, Revtex

Pre-flight Functionality Check to Enhance Mission Efficacy of Precision Guided Munitions

Precision-guided munitions (PGMs), because of their precision strike capability, are used extensively in the modern warfare. The efficacy of the mission is critically dependent on the successful deployment of the weapon. To ensure high level of effectiveness of these sophisticated weapons, these must be tested at regular intervals. Periodic functionality checks of these weapons are carried out using comprehensive characterisation systems. In addition to comprehensive testing, pre-flight functionality checks with the weapon strapped on to the launchplatform using portable test systems should be carried out. These functionality checks, also referred to as serviceability checks, perform Go/No Go testing of the weapon by focusing on one or two vital parameters of the guided weapon. Pre-flight functionality check of PGM allows a quick appraisal on the functional status of the vital operational parameters of relevance to efficacy of the mission. This review highlights the parameters that need to be checked, both for comprehensive testing of these weapons on a periodic basis and also those required for pre-flight functionality or readiness checks. International systems available for the purpose have also been reviewed, vis-à-vis, their capabilities and limitations to perform the two types of tests with particular emphasis on the pre-flight functionality checks with guided weapon in strap-on condition. Some alternative design approaches have also been proposed.Defence Science Journal, 2009, 59(5), pp.459-465, DOI:http://dx.doi.org/10.14429/dsj.59.154