Aerosol Characteristics at a high-altitude station Nainital during the ISRO-GBP Land Campaign-II

During the second land campaign (LC-II) organised by ISRO-GBP, extensive ground-based measurements of aerosol characteristics were carried out over Manora Peak (29.4oN; 79.5oE; 1951 metres above mean sea level), Nainital (a high altitude station located in the Shivalik ranges of Central Himalayas) during the dry, winter season (December) of 2004. These measurements included the spectral aerosol optical depths (AOD), columnar water vapour content (W), Total Columnar Ozone (TCO), total number concentration (NT) of near surface aerosols, mass concentration of black carbon (MB), aerosol mass loading (MT), and Global Solar Radiation. Based on these measured parameters, we present the results on the near-surface and columnar properties of atmospheric aerosols at Nainital.Comment: Published in the Proceedings of the ISRO-GBP Land-Campaign-II meeting, Physical Research Laboratory, Ahmadabad (Inida), March 200

Accuracy and Precision of Near Infra-red Spectroscopy (NIRS) versus Wet Chemistry in Forage Analysis

Near Infra-red Spectroscopy (NIRS) is an attractive option for forage analysis. NIRS is less labor intensive, nondestructive, rapid, environmentally friendly and provides accurate and precise results. However, many nutritionists are quick to brush off NIRS, citing ‘poor accuracy’. We evaluated the accuracy and precision of dry matter (DM), crude protein (CP), acid detergent fiber (ADF), and neutral detergent fiber (NDF) of 33 National Forage Testing Association (NFTA) proficiency test (PT) alfalfa hay samples analyzed by NIRS in 7 NIRS Forage and Feed Testing Consortium (NIRSC) member laboratories. The reference method averages (RMA), used to evaluate the NIRS results, were based on the wet chemistry results reported by numerous laboratories participating in the corresponding NFTA proficiency testing rounds. Thus, this study is a robust comparison of NIRS determined results with the corresponding wet chemistry results, which is still a “gold standard” to many nutritionists. These results demonstrate that when NIRS calibrations are developed using good science and applied properly, NIRS is as accurate as wet chemistry in forage nutritional analysis. Further, both intra-laboratory and inter-laboratory precision of NIRS methods are superior to wet chemistry method

Replica Placement on Bounded Treewidth Graphs

We consider the replica placement problem: given a graph with clients and nodes, place replicas on a minimum set of nodes to serve all the clients; each client is associated with a request and maximum distance that it can travel to get served and there is a maximum limit (capacity) on the amount of request a replica can serve. The problem falls under the general framework of capacitated set covering. It admits an O(\log n)-approximation and it is NP-hard to approximate within a factor of $o(\log n)$. We study the problem in terms of the treewidth $t$ of the graph and present an O(t)-approximation algorithm.Comment: An abridged version of this paper is to appear in the proceedings of WADS'1

Phase stability analysis in Fe-Pt and Co-Pt alloy systems: An augmented space study

We have studied the problem of phase stability in Fe-Pt and Co-Pt alloy systems. We have used the orbital peeling technique in the conjunction of augmented space recursion based on the tight binding linear orbital method as the method for the calculation of pair interaction energies. In particular, we have generalized our earlier technique to take into account of magnetic effects for the cases where the magnetic transition is higher than the order disorder chemical transition temperature as in the case of Co$_3$Pt. Our theoretical results obtained within this framework successfully reproduce the experimentally observed trends.Comment: 17 pages, 9 Figures. Accepted for publication in Journal of Physics : Condensed Matte

Anomalous Raman scattering from phonons and electrons of superconducting FeSe0.82_{0.82}

We report interesting anomalies in the temperature dependent Raman spectra of FeSe$_{0.82}$ measured from 3K to 300K in the spectral range from 60 to 1800 cm$^{-1}$ and determine their origin using complementary first-principles density functional calculations. A phonon mode near 100 cm$^{-1}$ exhibits a sharp increase by $\sim$ 5% in frequency below a temperature T$_s$ ($\sim$ 100 K) attributed to strong spin-phonon coupling and onset of short-range antiferromagnetic order. In addition, two high frequency modes are observed at 1350 cm$^{-1}$ and 1600 cm$^{-1}$, attributed to electronic Raman scattering from ($x^2-y^2$)to $xz$ / $yz$ $d$-orbitals of Fe.Comment: 19 pages, 4 figures, 1 tabl

Arsenic awareness creation

An estimated 20-30 million people consume water with arsenic concentrations above 0.05 mg/L (Ground Water Studies for Arsenic Contamination in Bangladesh, 2000) and are under risk of arsenic poisoning and adverse impact on health. With the huge number of people at risk and the widespread nature of the arsenic contamination (excess amounts of arsenic in tube-wells have been detected in 53 out of 64 Districts in Bangladesh), effective community participation is reckoned as a pre-requisite for a sustained arsenic mitigation program. To test promising arsenic mitigation treatment technologies (Rahman et al., 2000), the DPHE-Danida Arsenic Mitigation Pilot Project selected 4,000 families in the fringe areas of Chaumuhani and Lakshmipur Pourashavas in the coastal region of Bangladesh. In these Pilot Areas the Project employed and trained local women to carry out a Baseline survey, to conduct an intensive awareness creation campaign, to create demand for arsenic mitigation and to install and train the users in the operation of the DPHEDanida developed Bucket Treatment Unit (BTU) technology

A Congestion Controlled Logical Topology for Multihop Optical Networks

This paper considers the problem of designing the logical topology for any wavelength routed optical network, given the traffic matrix. An heuristic algorithm is proposed here for designing topologies based on the De-Bruijn graph and we compare our results with those obtained through the deterministic approach. The De-Bruijn graph is selected in this context as the logical topology due to some of its characteristic features like simple routing scheme, low diameter and small degree