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31.
In most used rotary valves in GM-type pulse-tube refrigerators the rotor makes heavy mechanical contact with the stator, so the valve is liable to wear, and large torques are needed. In this paper we will describe two types of valves, which have balanced forces on the rotor. In the first valve the rotor and the stator make no mechanical contact. The second type is a contact valve, like the classical valves, but the forces on the rotor are balanced in a different way. Therefore, these valves are less liable to wear, and the torques needed to rotate the valves are small. 相似文献
32.
A combination of experimental surface science techniques and density functional theory calculations has been employed to understand the adsorption and surface chemistry of a variety of C4 cyclic oxygenates on the (111) surface of Pd. These C4 cyclic oxygenates represent important probe molecules for production of chemicals from biomass-derived carbohydrates. The surface level studies of these intermediates reveal that adsorption and reactivity trends are determined by ring size/strain, degree of unsaturation, nature of the oxygenate function, and composition of the metal surface. 相似文献
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Tim Lynam John Drewry Will Higham Carl Mitchell 《Environmental Modelling & Software》2010,25(11):1291-1301
The development and use of a Bayesian Belief Network (BBN) model, within an adaptive management process for the management of water quality in the Mackay Whitsunday region of Queensland, Australia is described. The management goal is firstly to set achievable targets for water quality entering the Great Barrier Reef lagoon from the Mackay Whitsunday natural resource management region and then secondly to define and implement a strategy to achieve these targets. The BBN serves as an adaptive framework that managers and scientists may use to articulate what they know about the managed system. It then provides a tool to guide where, when and what interventions (including research) are most likely to achieve management outcomes. Importantly the BBN provides a platform for collective learning.BBN estimates of total suspended sediment (TSS) loads and event mean concentrations (EMCs) were compared to observed data and results from current best practice models. The BBN estimates were reasonable relative to empirical observations. Example results from the BBN are thereafter used to illustrate the use of the model in estimating the likelihood of exceeding water quality targets with and without proposed actions to improve water quality. Example results are also used to illustrate what spatial or land use elements might contribute most to exceeding water quality targets. Finally key limitations of the tool are discussed and important learnings from the process are highlighted. 相似文献
35.
Jürgen Weiss Ryan Hledik Roger Lueken Tony Lee Will Gorman 《The Electricity Journal》2017,30(10):50-57
The intersection of autonomous vehicles, ride sharing and transportation electrification could have significant implications for electric utilities. This paper analyses how the development of shared autonomous electric vehicles may make electrified transportation more likely and why this may lead to a more rapid than expected shift in the current transportation paradigm. We also discuss how these trends may affect utilities and suggest what they can do to prepare for the transition. 相似文献
36.
In a continuous development for more than three decades, dynamic light scattering (DLS) has evolved into a versatile and powerful technique for the determination of transport and other thermophysical properties of fluids. The success is founded on its application in a macroscopic thermodynamic equilibrium, i.e., without the need for employing external gradients, to determine a large variety of properties, which can be derived, in some instances even simultaneously, by an appropriate experimental approach and a corresponding signal analysis. The principles, essential features, and variants of the technique are reviewed, and a survey on the determination of various desired transport and thermophysical properties is given, both for the application of light scattering from bulk fluids and for the variant of surface light scattering (SLS). The stage of development and the corresponding uncertainties are discussed for the measurement of the individual quantities, and the performance of the method is demonstrated by representative experimental results for relevant fluids. 相似文献
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Patrick L Jacobs Erica R Goldstein Will Blackburn Ihsan Orem John J Hughes 《Journal of the International Society of Sports Nutrition》2009,6(1):9-11
Background
Recent research has indicated that short term administration of glycine propionyl-L-carnitine (GPLC) significantly elevates levels of nitric oxide metabolites at rest and in response to reactive hyperaemia. However, no scientific evidence exists that suggests such supplementation enhances exercise performance in healthy, trained individuals. The purpose of this study was to examine the effects of GPLC on the performance of repeated high intensity stationary cycle sprints with limited recovery periods in resistance trained male subjects. 相似文献39.
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