Synthesis and optical properties of water-soluble poly(vinylpyrrolidone) - modified fullerene C<Subscript>60</Subscript>

Summary  The effect of fullerene on the radical polymerization of N-vinylpyrrolidone with lauroyl peroxide in toluene was investigated kinetically. C₆₀ was found to act both as inhibitor and as retarder because the polymerization rate and the molecular weight of resulting poly(vinylpyrrolidone) is decreasing with the increase of the fullerene concentration (0-6.94 x 10^-4 mol l^-1). The water-soluble poly(vinylpyrrolidone)-modified fullerene C₆₀ compound was characterized by differential scanning calorimetric, Infrared and Raman spectroscopy, UV absorption and photoluminescence. Based on the results obtained by optical measurements, it is argued that by the covalent attachment of the polymeric radicals to fullerene cage the extended electronic conjugation system of the C₆₀ is broken leading to the appearance of a polyene structure.     

Beliefs about birth rank and their reflection in reality.

Beliefs about birth rank reflect what the society regards as social reality, and they may also influence that reality. Three studies found that people believe those with different birth ranks differ in their personalities, that higher birth ranks are likely to attain higher occupational prestige, and that the personality characteristics attributed to the various birth ranks favor the actual attainment of higher occupational prestige. In one example of such beliefs, firstborns were rated as most intelligent but least creative whereas the opposite was true of last-borns. The 4th study found that those with higher birth ranks in fact attain more prestigious occupations and actually do complete more years of schooling. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

THE DISCIPLE–RKF LEARNING AND REASONING AGENT

Over the years we have developed the Disciple theory, methodology, and family of tools for building knowledge-based agents. This approach consists of developing an agent shell that can be taught directly by a subject matter expert in a way that resembles how the expert would teach a human apprentice when solving problems in cooperation. This paper presents the most recent version of the Disciple approach and its implementation in the Disciple–RKF (rapid knowledge formation) system. Disciple–RKF is based on mixed-initiative problem solving , where the expert solves the more creative parts of the problem and the agent solves the more routine ones, integrated teaching and learning , where the agent helps the expert to teach it, by asking relevant questions, and the expert helps the agent to learn, by providing examples, hints, and explanations, and multistrategy learning , where the agent integrates multiple learning strategies, such as learning from examples, learning from explanations, and learning by analogy, to learn from the expert how to solve problems. Disciple–RKF has been applied to build learning and reasoning agents for military center of gravity analysis, which are used in several courses at the US Army War College.     

Turing machines with access to history

We study remembering Turing machines, that is Turing machines with the capability to access freely the history of their computations. These devices can detect in one step via the oracle mechanism whether the storage tapes have exactly the same contents at the moment of inquiry as at some past moment in the computation. The s(n)-space-bounded remembering Turing machines are shown to be able to recognize exactly the languages in the time-complexity class determined by bounds exponential in s(n). This is proved for deterministic, non-deterministic, and alternating Turing machines.     

Power system optimization

Long-term gas purchase contracts usually determine delivery and payment for gas on the regular hourly basis, independently of demand side consumption. In order to use fuel gas in an economically viable way, optimization of gas distribution for covering consumption must be introduced. In this paper, a mathematical model of the electric utility system which is used for optimization of gas distribution over electric generators is presented. The utility system comprises installed capacity of 1500 MW of thermal power plants, 400 MW of combined heat and power plants, 330 MW of a nuclear power plant and 1600 MW of hydro power plants. Based on known demand curve the optimization model selects plants according to the prescribed criteria. Firstly it engages run-of-river hydro plants, then the public cogeneration plants, the nuclear plant and thermal power plants. Storage hydro plants are used for covering peak load consumption. In case of shortage of installed capacity, the cross-border purchase is allowed. Usage of dual fuel equipment (gas–oil), which is available in some thermal plants, is also controlled by the optimization procedure. It is shown that by using such a model it is possible to properly plan the amount of fuel gas which will be contracted. The contracted amount can easily be distributed over generators efficiently and without losses (no breaks in delivery). The model helps in optimizing of fuel gas–oil ratio for plants with combined burners and enables planning of power plants overhauls over a year in a viable and efficient way.     

Coal oxidation at low temperatures: oxygen consumption, oxidation products, reaction mechanism and kinetic modelling

Coal oxidation at low temperatures (i.e. <100 °C) is the major heat source responsible for the self-heating and spontaneous combustion of coal and is an important source of greenhouse gas emissions. This review focuses on the chemical reactions occurring during low-temperature oxidation of coal. Current understanding indicates that this process involves consumption of O₂, formation of solid oxygenated complexes, thermal decomposition of solid oxygenated complexes and generation of gaseous oxidation products. Parameters, such as mass change, heat release, oxygen consumption, and formation of oxidation products in the gas or solid phase, have been used to qualitatively and quantitatively describe the oxidation process. Reaction mechanisms have been proposed to explain the characteristics of consumption of O₂, and formation of oxidation products in the gas and solid phases. Various kinetic models have also been developed to describe the rate of oxygen consumption and the rates of formation of gaseous oxidation products in terms of the rate parameters of the relevant reactions, oxidation time, temperature, and initial concentration of oxygen in the oxidising medium. Further research emphasis should be placed on the formation of the complete reaction pathways proceeding in the oxidation process and on the development of kinetic models applicable for predicting the self-heating and gas emission in a coal seam or stockpile.     

Formation of dioxins and furans during combustion of treated wood

Polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/F, dioxin) are produced in combustion of wood treated with copper-based preservatives. This review summarises and analyses the pertinent literature on the role of preservatives in the formation of dioxin in the low-temperature, vitiated environment that exists in the domestic combustion of wood, and in large-scale fires. Until recently, the role of preservatives was not thoroughly examined in the literature with respect to fires, as incineration attracted most of the research focus. However, latest studies have demonstrated that some current and emerging wood preservatives significantly increase dioxin formation during combustion in domestic stoves and in fires. The following pathways are identified: (i) copper, a common biocide that is chemically bound to the wood, is an important dioxin catalyst, (ii) preservative metals promote smouldering of wood char following cessation of flaming, providing the required temperature environment for dioxin formation, and (iii) chlorinated organics added as secondary preservative components yield dioxin precursors upon thermal decomposition. These conclusions indicate that it remains hazardous to dispose of preservative impregnated timber via domestic combustion even if arsenic is not present.