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AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

SummaryWe conducted a decomposition analysis of material flows in a dynamic system, focusing on factors in the generation of waste consumer durables. A methodology for the analysis of consumer durables was developed and applied to three common consumer durables: cathode ray tube TVs, refrigerators, and passenger cars. The methodology decomposed changes in the numbers of waste products into three factors: changes in lifespan distribution, past trends in replacement sales, and past trends in sales for additional purchases. The decomposed equation clearly showed that the number of waste products would not necessarily be reduced by lifespan extension alone. This is because the number of waste products generated is affected not only by current lifespan distribution but also by past trends in sales for replacement and in additional purchases. The results show that changes in past replacement sales influence the current generation of waste, even if current replacement sales are declining. To reduce the generation of waste products on a short‐term basis, lifespan must be extended until the waste‐reducing effect of lifespan extension exceeds the waste‐increasing effect of the other two factors. From a long‐term perspective, controlling current replacement and additional purchases can be used to prevent future waste product generation.

AbstractThe paper describes some of the simulations of measurements taken using EMTDC to estimate power system load models. It shows how different load structure and non‐ideal conditions in power systems influence results of the measurements. On the basis of simulations performed different load models are proposed for various classes of load compositions. An example of load parameter estimation from measured results is given.

A detailed pollen record from the Ocean Drilling Program Site 820 core, located on the upper part of the continental slope off the coast of northeast Queensland, was constructed to compare with the existing pollen record from Lynch's Crater on the adjacent Atherton Tableland and allow the production of a regional picture of vegetation and environmental change through the last glacial cycle. Some broad similarities in patterns of vegetation change are revealed, despite the differences between sites and their pollen catchments, which can be related largely to global climate and sea-level changes. The original estimated time scale of the Lynch's Crater record is largely confirmed from comparison with the more thoroughly dated ODP record. Conversely, the Lynch's Crater pollen record has assisted in dating problematic parts of the ODP record. In contrast to Lynch's Crater, which reveals a sharp and sustained reduction in drier araucarian forest around 38,000 yrs BP, considered to have been the result of burning by Aboriginal people, the ODP record indicates, most likely, a stepwise reduction, dating from 140,000 yrs BP or beyond. The earliest reduction shows lack of a clear connection between Araucaria decline and increased burning and suggests that people may not have been involved at this stage. However, a further decline in araucarian forest, possibly around 45,000 yrs BP, which has a more substantial environmental impact and is not related to a time of major climate change, is likely, at least partially, the result of human burning. The suggestion, from the ODP core oxygen isotope record, of a regional sea-surface temperature increase of around 4 degrees C between about 400,000 and 250,000 yrs BP, may have had some influence on the overall decline in Araucaria and its replacement by sclerophyll vegetation. (C) 2000 Elsevier Science B.V. All rights reserved.

Abstract Thermal hydraulic tests on the core and core–bottom structure of the high-temperature engineering test reactor (HTTR) were carried out with the helium engineering demonstration loop (HENDEL) under simulated reactor operating conditions. The HENDEL was composed of helium gas circulation loops, mother sections (M 1 and M 2 ) and adaptor section (A), and two test sections, i.e. the fuel stack test section ( T 1 ) and in-core structure test section ( T 2 ). In the T 1 test section simulating a fuel stack of the core, thermal and hydraulic performances of helium gas flowing through a fuel block were investigated for thermal design of the HTTR core. In the T 2 test section simulating the core–bottom structure, demonstration tests were performed to verify the structural integrity of graphite and metal components, seal performance against helium gas leakage among the graphite permanent blocks and thermal mixing performance of helium gas. The above test results in the T 1 and T 2 test sections were applied to the detailed design and licensing works of the HTTR and the HENDEL-loop was dismantled in 1999.

The purpose of this paper is to provide an overview of the engineering methods, tools, design solutions and verification methods used in the design of HVDC converter substations subject to acoustic requirements. The sound generation section of the paper describes how the sound power level radiated from electrical components can be calculated based on the load. The sound propagation section describes how the sources affect the sound pressure level at emission points of interest. A method to break down the acoustic requirement to the component level and practical studies to verify the concordance with the requirements are also illustrated. Different solutions for screening and absorption are described as well as measurement methods. The paper also describes a working method used to fulfil outdoor acoustic requirements. >

Phlebia sp. MG-60 is a white-rot fungus that produces ethanol with high efficiency from lignocellulosic biomass without additional enzymes. Through engineering of this powerful metabolic pathway for fermentation in Phlebia sp. MG-60, chemical compounds other than ethanol could be produced. Here, we demonstrate sugar accumulation from unbleached hardwood kraft pulp and conversion of xylose to xylitol by pyruvate decarboxylase (pdc)-negative Phlebia sp. MG-60. We isolated Phlebia sp. strain MG-60-P2 from protoplasts to unify the protoplast phenotypes of the regenerated strains. Homologous recombination achieved a stable pdc-knockout line, designated KO77. The KO77 line produced traces of ethanol, but accumulated xylitol from xylose or glucose from unbleached hardwood kraft pulp. These metabolic changes in the pdc-knockout strain reflect the potential of metabolic engineering in Phlebia sp. MG-60 for direct production of chemical compounds from lignocellulosic biomass.

Nanotechnology, and particularly nanoparticles (NPs), command significant attention across diverse fields such as medicine, chemistry, and engineering. NPs are integrated into a base material through various techniques, such as dispersion, coating, and encapsulation. This review intends to offer an evaluation of the implementation of NPs in nuclear energy and radiation protection. Particular focus is given to nanofluids - suspensions of NPs in a base fluid - and their impact on the thermal–hydraulic and neutronic attributes of nuclear reactor cores. Discussion centers on how substituting water with nanofluids as a coolant can modify these characteristics. Computational modeling and experimental methods of nanofluids are examined, highlighting an enhanced heat transfer capacity under both regular and emergency reactor conditions. The influence of nanofluids on neutronic parameters, aiming for optimized operation and safety of nuclear reactors, is also explored. Furthermore, the potential of NPs for radiation shielding is considered, underlining their capability to attenuate radiation effects. Examples are drawn from the addition of NPs to containment structures in nuclear facilities and their use in radiotherapy, as well as enhancing radiation shielding in imaging techniques. Finally, the review encompasses the effects of nanofluids on surface oxidation and corrosion. The importance of these factors lies in their substantial impact on heat transport properties and potential for corrosive damage.