Chemical characterization of liquefaction products of an inertinite enriched northern Alaska coals

A Northern Alaskan coal rich in inertinites was further enriched by density gradient separations. The degree of condensation of the enriched coal was estimated to be low, mainly 3 ring. The reactivity of the inertinite enriched coal was determined by comparing yields from direct liquefaction with H2 at 0 and 30 minute residence times, 425°C, using an H-donor solvent in one case and moly-catalyst in the other with H2 pressures of 500 and 1000 psig respectively. Solid products were analyzed by Fourier Transform Infrared Spectroscopy while the hexane solubles were separated into various chemical classes, viz. alkanes, neutral polycyclic aromatic compounds, hydroxy polycyclic aromatic oxygen heterocycles, and secondary, tertiary amino polycyclic aromatic compounds. The chemical compounds in these fractions were further analyzed by gas chromatography - mass spectrometry (GC-MS)an dcapillary gas chromatography. This work confirmed earlier data showing that inertinites are not as determinental to liquefaction as previously thought

The Global Dimensions of Conflict in Sri Lanka

This paper seeks to identify and chart the global dimensions of the political conflict and civil war in Sri Lanka. The global dimensions are visualised in terms of the ways in which the dynamic of the conflict has been embedded within two parallel and closely inter-dependent trajectories relating to the global economy and global politics. The conflict, which has taken various forms since the inception of the separatist movement in the early 1970s, spans a number of distinct historical phases that straddle important external political, economic and cultural changes, including the end of the cold war, the rise of a global liberal economic order, and the effects of the emerging global "war on terrorism" - all of which are playing an important role in the dynamics of the conflict. In the face of the extended stalemate that has characterised the internal political and military dynamics of the conflict, this paper argues that the politics of the war/peace process can be better understood by situating them within these larger historical and global transformations.

Quickest Change Detection of a Markov Process Across a Sensor Array

Recent attention in quickest change detection in the multi-sensor setting has been on the case where the densities of the observations change at the same instant at all the sensors due to the disruption. In this work, a more general scenario is considered where the change propagates across the sensors, and its propagation can be modeled as a Markov process. A centralized, Bayesian version of this problem, with a fusion center that has perfect information about the observations and a priori knowledge of the statistics of the change process, is considered. The problem of minimizing the average detection delay subject to false alarm constraints is formulated as a partially observable Markov decision process (POMDP). Insights into the structure of the optimal stopping rule are presented. In the limiting case of rare disruptions, we show that the structure of the optimal test reduces to thresholding the a posteriori probability of the hypothesis that no change has happened. We establish the asymptotic optimality (in the vanishing false alarm probability regime) of this threshold test under a certain condition on the Kullback-Leibler (K-L) divergence between the post- and the pre-change densities. In the special case of near-instantaneous change propagation across the sensors, this condition reduces to the mild condition that the K-L divergence be positive. Numerical studies show that this low complexity threshold test results in a substantial improvement in performance over naive tests such as a single-sensor test or a test that wrongly assumes that the change propagates instantaneously.Comment: 40 pages, 5 figures, Submitted to IEEE Trans. Inform. Theor