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31.
Peter Lloyd Woodfield Andrew Seagar Wayne Hall 《International Journal of Thermophysics》2012,33(2):259-278
Vibrating wire viscometers rely on the principle that the viscosity of the fluid surrounding the wire provides the dominant
damping action on the motion of the wire. However, some residual damping is always present due to other effects such as internal
friction of the wire (anelastic relaxation), losses through the wire supports, and magnetic damping. Magnetic damping is a
physical mechanism that has received relatively less attention than internal friction in the context of viscometers. The phenomenon
arises because the current induced by the motion of the wire contributes to the magnetic field in such a way as to oppose
its own motion. For a test circuit using a 40 μm diameter tungsten wire in a 0.3 T magnetic field, surprisingly, the effect
of magnetic damping was found to be of a similar order of magnitude to other non-viscous damping effects. The effect can be
accounted for by including the internal impedance of the oscillating voltage source in the model and it disappears completely
for a perfect oscillating current source. 相似文献
32.
33.
Careful selection of steaming and attrition conditions during thermo‐mechanical pretreatment can increase enzymatic conversion of softwood
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34.
Douglas A. Stow Christopher D. Lippitt Lloyd L. Coulter Andrew C. Loerch 《International journal of remote sensing》2018,39(5):1441-1458
The objective of this article is to synthesize research findings and requirements pertaining to development of time-sensitive remote-sensing systems (TSRSS) that support decision-making pertaining to post-hazard assessment of damage to what we define as hyper-critical infrastructure (HCI), based on an aerial imaging approach known as repeat station imaging (RSI). The following TSRSS components are addressed and related findings are reported: (1) understanding information requirements of emergency managers pertaining to damage of HCI; (2) flight planning and data capture requirements for supporting bi-temporal RSI pairs; (3) automatic image registration and shadow classification and normalization routines applied to RSI pairs; (4) damage detection and delineation approach that exploits simple temporal differences in image brightness to automatically, reliably, and robustly delineates new cracks associated with damage; and (5) rapid data and information transfer to emergency managers. The highest priority follow-on research topics are: (1) integrating small unmanned aerial systems (sUAS) with the RSI approach, while enabling multiple view perspectives other than vertical (i.e. nadir pointing) and (2) developing and testing of machine learning routines for automatic identification of damage features from RSI pairs, particularly those captured from integrated sUAS–RSI. 相似文献
35.
Acid resistance of inorganic polymer binders. 1. Corrosion rate 总被引:1,自引:1,他引:0
Redmond R. Lloyd John L. Provis Jannie S. J. van Deventer 《Materials and Structures》2012,45(1-2):1-14
The resistance to acid-induced corrosion of inorganic polymer (including ??fly ash geopolymer??) binders is examined, by exposing specimens to nitric and sulphuric acids at pH values between 1 and 3, and measuring the corroded depth as a function of exposure time. The inorganic polymer binders are shown to be affected by acid attack by surface corrosion, which contradicts some previous claims of extremely high acid resistance in such binders. Corroded depth is shown to be a more sensitive measure of the performance of inorganic polymer binders than change in mass, because acid attack on the highly-connected aluminosilicate network of an inorganic polymer binder leads to the formation of an apparently intact, but physically weak and porous, reaction product layer on the sample surface, rather than complete disappearance of the binder as is often the case for other binder types. A strong correlation between permeability and resistance to acid attack is noted across a wide range of inorganic polymer formulations, including samples based on fly ash, ground granulated blast furnace slag, and mixtures of the two. The presence of calcium (supplied either by a Class C fly ash or by slag) and of high alkali concentrations each show a positive influence on acid resistance, which is attributed to the reduction in mass transport rates through the finer and more tortuous pore networks of such binders. 相似文献
36.
37.
S. R. J. Saunders M. K. Hossain B. Kent D. M. Lloyd 《Materials at High Temperatures》2013,30(2):63-73
The results of an investigation of the sulphidation behaviour of lncoloy BOOH and AISI 310 stainless steel in coal combustion conditions at temperatures between 650°C and 900°C are presented. Laboratory tests were carried out in controlled environments in the presence of solids representative of fluidized bed combustor operation. The morphology and composition of scale formed during sulphidation was examined and compared with that from tube samples removed from test rigs operated by the National Coal Board. The results have shown that at 900°C a gas mixture corresponding to the equilibrium conditions close to the coexistence point for CaS04, CaO and CaS on the phase stability diagram is sufficient to induce sulphidation. However, at lower temperatures an interaction between the deposit and the protective oxide is necessary and in some cases the presence of typical contaminants found in coals is an added requirement. The morphology of the corrosion products found in practice can be reproduced under controlled conditions in laboratory tests. The results are interpreted in terms of likely mechanisms of the processes involved. 相似文献
38.
在澳大利亚,伴随着妇女就业和单亲家庭的增长,多数家庭和儿童都非常依赖于儿童看护服务,比如,社区幼儿园、幼儿中心、临时家 相似文献
39.
Lloyd Rod Win 《Journal of the American Planning Association. American Planning Association》2013,79(4):175-180
The land use model recasts an unsuccessful urban form of the past. Concentric rings of declining land value begin at the intense, historic center and grade down through concentric rings to become the city plan. Little planning remains after such a model is accepted. The new freedom of the auto-age city is lost to the principle of a falling body. Further, the land use model plan restricts mobility of resident and employer by type, each to his ring Urban land value patterns are sustained by public action or inaction. A true city plan musters this power to form the best possible city. 相似文献
40.
João P. F. Mota Viviane G. P. Ribeiro Fernando L. F. da Silva Antônio E. C. Junior Davi R. Oliveira Lloyd R. V. Kotzebue 《分离科学与技术》2016,51(14):2473-2483
The present work made a comparative study between two purification methods, column chromatography and recrystallization, for compounds derived from cardanol, a by-product of the cashew industry (Anacardium occidentale L.). The compounds were successfully synthesized and characterized, focusing our attention to results obtained in terms of yield, purity, generation of solid waste and amount of solvent used in each purification process. For all the synthesized compounds, the amount of solvent used was greatly reduced in the recrystallization process, with purities above 80%, when compared to chromatographic column, which still demands high amounts of eluent. 相似文献