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1.
In scientific communication, ambiguities in term usage can go unnoticed due not only to the distance between reader and writer but also to the existence of highly specialized scientific subcommunities. This commentary therefore aims at raising awareness about the use of terms that have different meanings within different hydrological subcommunities such as field hydrology, hydrological modelling, or statistical hydrology. To do so, we discuss the use of the following commonly used hydrological terms: sample, runoff, discharge, and streamflow. We performed three types of analyses to provide evidence of term usage and understanding, including both qualitative and quantitative approaches: a drawing exercise, a survey, and a literature corpus analysis. These analyses allow for a comparison of spontaneous definitions and the actual use of these terms in scientific publications. Our various information sources revealed that the dialogue between hydrologists within and across subdisciplines is substantially influenced by personal conceptualizations of terms that are not always shared across conversational partners. The terms discussed and illustrated in this commentary have to be seen as a small sample used to demonstrate the need for a thoughtful use of hydrological terms when communicating research, not only to a general audience but even across subdisciplines within hydrology. 相似文献
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This study investigates the association between mean and turbulent flow variables and the movement of individual particles in a gravel‐bed river. The experimental design implemented in the Eaton‐North River (Québec, Canada) is based on the simultaneous observations at a high temporal resolution of both particle movements as bedload using an underwater video camera and of the streamwise and vertical flow velocity components using a vertical array of three electromagnetic current meters (ECMs). The frequency and distance of displacement of particles larger than 20 mm that were sliding or rolling on the bed were measured from a 10 minutes long film. Mean and turbulent flow properties obtained for periods without sediment transport are compared to those when particles were sliding and rolling. When particles are sliding, weak differences are present for the mean streamwise velocity and normal vertical stresses. Instantaneous Reynolds shear stresses are significantly lower for sliding events which was not expected but could be explained by the important dominance of Quadrant 3 events (inward interactions). When particles are rolling, only the vertical normal stresses show a weak difference from those observed in the absence of transport but they tend to occur when Quadrant 2 (ejections) dominate the flow field. For both sliding and rolling particles, vertical and/or streamwise fluid accelerations show high magnitude values when compared to periods without transport. For sliding particles, streamwise acceleration is mostly negative and combines most of the time with a positive vertical acceleration. For rolling particles, streamwise and vertical acceleration are predominantly of opposite sign. These results suggest that fluid acceleration or deceleration in the streamwise and vertical directions is affecting the pressure field around particles. In this study, fluid acceleration seems to play a more important role than Reynolds shear stress or normal stresses for bedload movements. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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The Adaptation Fund, established under the Kyoto Protocol of the United Nations Framework Convention on Climate Change (UNFCCC), has now been approving funding for adaptation projects for more than two years. Given its particular institutional status and specific focus on concrete adaptation, it is particularly relevant to study the initial experiences of it for any future upscaling of international adaptation finance, despite the fact that its own resources are getting scarce. Alternative rationales for allocating funds, based on equity and efficiency concerns at both international and subnational levels, are here tested against the criteria and priorities of the Fund and decisions made on project approval. It is concluded that equity concerns appear to be the primary motivation and that allocation is de facto made between states rather than by considering inequity between subnational communities. However, the currency of vulnerability for determining equitable outcomes in allocation decisions has not been formalized, despite its central importance to the Fund. Instead, uniform national caps have been introduced. Such an equality approach can be considered inequitable. Finally, it is noted that although the Adaptation Fund Board has continuously developed its proposal review practices and adopted a learning-by-doing approach, it should provide both a further specification of the evaluation criteria and a compilation of best practices from approved proposals, and moreover enhance the transparency of the review process, all of which would clarify its core priorities for current and future project proponents. 相似文献
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Mathematical models of hydrocarbon formation can be used to simulate the natural evolution of different types of organic matter and to make an overall calculation of the amounts of oil and/or gas produced during this evolution. However, such models do not provide any information on the composition of the hydrocarbons formed or on how they evolve during catagenesis.From the kinetic standpoint, the composition of the hydrocarbons formed can be considered to result from the effect of “primary cracking” reactions having a direct effect on kerogen during its evolution as well as from the effect of “secondary cracking” acting on the hydrocarbons formed.This report gives experimental results concerning the “primary cracking” of Types II and III kerogens and their modelling. For this, the hydrocarbons produced have been grouped into four classes (C1, C2–C5, C6–C15 and C15+). Experimental data corresponding to these different classes were obtained by the pyrolysis of kerogens with temperature programming of 4°C/min with continuous analysis, during heating, of the amount of hydrocarbons corresponding to each of these classes.The kinetic parameters of the model were optimized on the basis of the results obtained. This model represents the first step in the creation of a more sophisticated mathematical model to be capable of simulating the formation of different hydrocarbon classes during the thermal history of sediments. The second step being the adjustment of the kinetic parameters of “secondary cracking”. 相似文献
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Elise Brower 《Geochimica et cosmochimica acta》1973,37(1):155-158
Crystals of synthetic barite (BaSO4), celestite (SrSO4), and their solid solutions were recrystallized from brine by thermal cycling. Electron probe microanalyses show that the solid solutions are homogeneous within detection limits. The molar composition of solid solution crystals approximates the ideal value based on the ratio of equilibrium constants for barium and strontium sulfates. 相似文献
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