Efficient energy systems with CO2 capture and storage from renewable biomass in pulp and paper mills

This paper investigates the impact of combining CO₂ capture and storage with alternative systems for biomass-based combined heat and power production (CHP) in Kraft pulp and paper mills. We compare heat, power, and CO₂ balances of systems with alternative configurations of the CHP and CO₂-capture systems. Because the captured CO₂ comes from renewable biomass, the studied systems yield negative CO₂ emissions. It is shown that pulp mills and integrated pulp and paper mills have the potential to become net exporters of biomass-based electricity while at the same time removing CO₂ from the atmosphere on a net basis. The study shows that that the overall best CO₂ abatement is achieved when CO₂ capture is carried out within a biomass integrated gasifier with combined cycle where the syngas undergoes a CO-shift reaction. This configuration combines efficient energy conversion with a high CO₂ capture efficiency. Furthermore, cost curves are constructed, which show how the cost of CO₂ capture and storage in pulp and paper mills depends on system configuration and the CO₂ transportation distance.     

Ozonation of unstretched natural rubber film from Hevea brasiliensis studied by ozone consumption and 13C NMR

Unstretched films of natural rubber (NR) from Hevea brasiliensis were exposed to ozone flow of 15 ml min^?1 from 4 to 300 min. The efficiency of reaction was determined by ozone consumption of NR films. Plots of reacted ozone mass versus film thickness show that the ozone penetration and the ozone reaction progressed into deeper layers (170 µm) than described in the literature (～0.5 µm). The previous proposed model based on viscometry measurements was corroborated by ozone consumption results. The effect of thickness on the O₃/NR stoichiometric ratio indicated that the diffusion process that controls the ozonation in unstretched film does not consist of the boundary progression behind which all reactive sites have been saturated. Ozonation in unstretched rubber film, while being less efficient than ozonolysis in solution, does have a reaction efficiency of the same order of magnitude. NMR spectroscopy was used to characterise the products formed by ozonation. Copyright © 2004 Society of Chemical Industry     

The emergence of social dominance in young boys' play groups: Developmental differences and behavior correlates.

This study examined relations among dominance, sociometric preference, and social behavior in groups of 1st- and 3rd-grade boys. 20 groups of 6 unacquainted boys met for 5 45-min semistructured play sessions on consecutive days. Sociometric interviews yielded daily social preference scores. Boys' social behaviors were coded from video records into discrete categories. Dominance hierarchies were formed on the basis of asymmetry (receiving vs initiating) of peer-directed aggression or persuasion attempts. Group-level results indicated that the least coherently organized groups were those containing younger boys and those in which aggression occurred at a high rate. Individual-level results indicated that dominance was associated with social preference to a greater degree among younger than older boys. Dominance was more highly related to leadership in older than younger boys. Implications of these findings are discussed with respect to the role of aggression in the social organization of boys' peer groups. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Self-administration of alcohol before and after a public speaking challenge by individuals with social phobia.

[Correction Notice: An erratum for this article was reported in Vol 16(3) of Psychology of Addictive Behaviors (see record 2009-17717-001). On page 121, in the abstract, the penultimate sentence incorrectly reads, “As predicted, participants consumed more alcohol following the anxiety challenge than following the control task; however, the opposite pattern was evidenced for drinking following the 2 activities.” The sentence should read as follows: “As predicted, participants consumed more alcohol following the anxiety challenge than following the control task; however, the opposite pattern was evidenced for drinking preceding the 2 activities.”] K. Abrams, M. Kushner, K. Medina, and A. Voight (2001) showed that alcohol attenuates social anxiety symptoms in socially phobic individuals. This article examines whether social anxiety symptoms can lead to increased alcohol use in this same population. Forty-four individuals with social phobia attended 2 laboratory sessions, spaced 1 week apart, in groups of approximately 10. Participants underwent a social anxiety challenge during 1 session and a control task during the other. Half of the sample self-administered alcohol immediately before, and half immediately after, these 2 activities. As predicted, participants consumed more alcohol following the anxiety challenge than following the control task; however, the opposite pattern was evidenced for drinking following the 2 activities. These findings add to an understanding of why social phobia and alcohol problems tend to co-occur. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reciprocal Citizens Exchange: A Confidence-Building Alternative to Nuclear Deterrence

This paper articulates a new and very different approach to deterrence in the nuclear age, one focussed on the underlying causes rather than the more easily visible effects of superpower intransigence, one based on positive rather than negative incentives, and one with the unusual potential to remove barriers (whether perceived or real) between political adversaries rather than continuously to create them. I suggest a deterrent ``force,' or perhaps more appropriately a ``restraining presence,' that uniquely combines inhibition of war-like or destabilizing acts in the short term with the simultaneous enhancement of transnational understanding over the longer term, at all levels of the body politic. Specifically, I propose a highly visible, mutially endorsed and deliberately massive effort by both the U.S. and the U.S.S.R. in support of a confidence-building program involving the reciprocal exchange, from one nation to the other, of large numbers of citizen ``hostages' chosen from all walks of life. Over a period of a generation or more, these carefully-selected and well-prepared volunteers would have the opportunity to lay the psychological and political groundwork for a significant and powerful, yet non-violent and gradual, shift in the conceptualization of deterrence currently endorsed by both superpowers.     

A subspace iteration method for the eigensolution of large undamped gyroscopic systems

This paper presents an efficient and numerically stable algorithm for computing accurately the eigenvalues of smallest moduli and the associated eigenvectors of the quadratic eigenproblem which arises in the analysis of spinning systems. Derived from the well-known standard subspace iteration method, this solution procedure takes full advantage of the banded configuration of the structural matrices, and of the specific nature of gyroscopic systems. A numerical example is presented to show the efficiency and accuracy of the algorithm.     

Adaptive gait control for a walking robot

Walking vehicles have the potential to emulate the superior off-road mobility of biological systems. However, it is important to make the walking machine terrain adaptive and versatile, and to minimize man's role as an operator in order to realize this potential. Terrain adaptive locomotion involves intelligent foothold selection and the control of gait to produce the desired motion. This requires a departure from the idealized, structured stepping patterns for statically stable gaits which have been the object of considerable research. A modified wave gait is used to demonstrate that it is possible for the vehicle velocity to be varied continuously in accordance with higher level commands even with irregular, asymmetric, and changing support patterns, A varying duty factor is employed to enable optimal leg cycling frequencies. Implementation of gait control algorithms and results from a computer simulation are also presented.