Experimental Study of Magnetic Slurries Regarding Magnetic Properties

Abstract-The aim of this study was to assess the basic magnetic properties of a mixture composed of a commercial lubricant and soft magnetic iron particles, where the particle content is significantly higher than in conventional magnetic fluids, due to the fact that the particles verge on the sedimentation level. This so called magnetic slurry can, then, be regarded as a highly ductile magnetic conductin material for tentative use in magnetic circuit that can cgange shape under operation. The high particle content results in high saturation field densities that extend the application field towards electric power en ineering. This paper, therefore, focuses on properties life relative permeability, losses, the Q-factor and the efficiency for the power fre uencies 50 and 400 Hz. It shows that the relative permea%ilities are low (below 10). The values of the efficiency and the Q-factor decrease considerably above 0.5 T. That limit$ the application of the studied slurry in electric power engineering. In such applications, the powder properties must be improved

Developing a coal quality expert: The prediction of ash deposit effects on boiler performance

The overall objective of the Coal Quality Expert (CQE) Clean Coal I Program is the development of a Coal Quality Expert -- a comprehensive PC based expert system for evaluating the potential for coal cleaning, blending and switching options to reduce emissions while producing the lowest cost electricity. A key part of the CQE model will be the development of a sub-model to predict the effects of ash deposition on boiler performance under various operating conditions. To facilitate sub-model development, a combination of full, pilot, and bench scale testing has been carried out on a series of coals and coal blends which were of interest to the Public Service of Oklahoma (PSO) at their Northeastern Station. A series of full-scale tests were also performed on PSO's Northeastern Unit {number sign}4 to characterize boiler performance when firing a baseline coal'' (their normal or desired fuel feed stock) and two blends comprised of the baseline coal blended with various amounts of an alternate coal. Actual furnace conditions were then closely matched during a series of tests performed in Combustion Engineering's pilot scale combustor, the Fireside Performance Test Facility (FPTF). Pilot scale testing allowed in-depth analyses of furnace deposits during and after formation under well-controlled conditions. Ash deposit properties were characterized during pilot scale furnace operation and in subsequent bench scale analyses. Determination of deposit behavior as a function of important operating parameters during the FPTF testing has permitted the prediction of expected performance for various coal/coal blends in PSO's Northeastern Units and allows a prediction of boiler performance for other units firing these fuels

電極間の部分放電により発生する電磁波の周波数解析

The investigated electrode configuration was composed of a needle electrode and a plane electrode. The discharge inception voltage rose as the gap length increased. This change on the discharge inception voltage should be affected by changing the electric field. When the electromagnetic wave was measured using a spectrum analyzer, the electromagnetic waves with around 150 MHz were detected in oil. While, the waves with around 50 MHz were detected in air. In addition, the appearance of the discharge images was observed with the image-intensified still camera

Nanotechnology, governance, and public deliberation: What role for the Social Sciences?

In this article we argue that nanotechnology represents an extraordinary opportunity to build in a robust role for the social sciences in a technology that remains at an early, and hence undetermined, stage of development. We examine policy dynamics in both the United States and United Kingdom aimed at both opening up, and closing down, the role of the social sciences in nanotechnologies. We then set out a prospective agenda for the social sciences and its potential in the future shaping of nanotechnology research and innovation processes. The emergent, undetermined nature of nanotechnologies calls for an open, experimental, and interdisciplinary model of social science research

The role of hydrogen and fuel cells in the global energy system

Hydrogen technologies have experienced cycles of excessive expectations followed by disillusion. Nonetheless, a growing body of evidence suggests these technologies form an attractive option for the deep decarb onisation of global energy systems, and that recent improvements in their cost and performance point towards economic viability as well. This paper is a comprehensive review of the potential role that hydrogen could play in the provision of electricity, h eat, industry, transport and energy storage in a low - carbon energy system, and an assessment of the status of hydrogen in being able to fulfil that potential. The picture that emerges is one of qualified promise: hydrogen is well established in certain nic hes such as forklift trucks, while mainstream applications are now forthcoming. Hydrogen vehicles are available commercially in several countries, and 225,000 fuel cell home heating systems have been sold. This represents a step change from the situation of only five years ago. This review shows that challenges around cost and performance remain, and considerable improvements are still required for hydrogen to become truly competitive. But such competitiveness in the medium - term future no longer seems an unrealistic prospect, which fully justifies the growing interest and policy support for these technologies around the world