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541.
Remotely sensed data have been used extensively for environmental monitoring and modeling at a number of spatial scales; however,
a limited range of satellite imaging systems often constrained the scales of these analyses. A wider variety of data sets
is now available, allowing image data to be selected to match the scale of environmental structure(s) or process(es) being
examined. A framework is presented for use by environmental scientists and managers, enabling their spatial data collection
needs to be linked to a suitable form of remotely sensed data. A six-step approach is used, combining image spatial analysis
and scaling tools, within the context of hierarchy theory. The main steps involved are: (1) identification of information
requirements for the monitoring or management problem; (2) development of ideal image dimensions (scene model), (3) exploratory
analysis of existing remotely sensed data using scaling techniques, (4) selection and evaluation of suitable remotely sensed
data based on the scene model, (5) selection of suitable spatial analytic techniques to meet information requirements, and
(6) cost–benefit analysis. Results from a case study show that the framework provided an objective mechanism to identify relevant
aspects of the monitoring problem and environmental characteristics for selecting remotely sensed data and analysis techniques. 相似文献
542.
水喷淋控制烟气输运的大涡模拟研究 总被引:4,自引:0,他引:4
本文采用大涡模拟方法研究了烟气输运和水喷淋之间的相互作用问题。研究目的是探讨水喷淋(或细水雾)对烟气输运的控制和抑制的有效性和要行性。为了有效地模拟烟气输运过程,本文采用了低马赫数近似下的三维可压缩滤波形式的Navier-Stokes方程进行有限差分法数值求解。烟气的生成和运动采用携带燃烧反应热的Lagrangian粒子(热元模型)来模拟,同时喷淋器喷出的细水雾也采用模型模拟。在本文的研究中,烟气由一个独立的火池产生并且被一股来流(或风)驱动,从而在一个方形槽道里形成烟气输运,在火池下游槽道的顶部布置若干个喷淋器并喷出水雾,以便探讨水雾对烟气输运的控制作用。本文着重分析讨论了不同喷淋角和水雾半径下水雾对烟气输运的控制和抑制效果。 相似文献
543.
544.
Anat Arbhabhirama Shlomo Angel Marcia R. Brewster 《Journal of the American Water Resources Association》1981,17(3):483-493
This paper discusses strategies for the development of water resources, emphasizing the delivery of reliable water supplies, for both domestic and production purposes, to every village and to every farmer. This necessitates a shift of emphasis from the construction of large storage reservoirs to the construction, operation, and maintenance of water distribution systems capable of reaching the largest number of farms, and a shift from projects that benefit the few, to projects that benefit the many. Water distribution in this context takes on three interrelated meanings: a geographical meaning, a technical meaning, and an economic meaning. The geographical meaning focuses on the spatial distribution of the recipient population as a key to identifying the proper distribution of water projects in physical space. The technical meaning relates to the physical distribution of water through canal systems to the farmers' fields. The economic meaning refers to the equitable distribution of benefits from water projects. The paper provides an illustration of the need for an emphasis on distribution, using the state of development of water resources in northeast Thailand as an example, with a proposed program for the further development of these resources. The northeast, the poorest region in the country, has been recognized by the Government of Thailand as a priority area for accelerated regional development efforts. 相似文献
545.
Edwin T. Engman William J. Gburek Leslie H. Parmele James B. Urban 《Journal of the American Water Resources Association》1971,7(3):495-505
ABSTRACT The problems encountered in estimating scale parameters in interdisciplinary watershed research are discussed. Meteorology, hydrology, geology and water quality are discussed with respect to their individual strengths and weaknesses when applied to different scale problems. Areas where incompatibilities exist are pointed out and suggestions are made for effecting compromise. A watershed scale of roughly a hundred acres may be the scale at which all disciplines can effect optimum interaction. 相似文献
546.
为了全面了解在不同通风模式下地铁十字换乘车站站厅火灾发展规律,通过在8A编组地铁十字换乘车站公共站厅层开展1 MW规模的全尺寸火灾实验,对不同通风模式下换乘地铁车站站厅层公共区火灾场景下的烟气前锋到达时间、烟气扩散与沉降范围和楼扶梯处温度等参数进行分析研究。研究结果表明:在换乘线路A线站厅层发生火灾时,受到出入口自然风以及站厅层空间结构的影响,站厅内形成了由站厅北侧向南侧方向的风压,有效抑制了烟气向B线站厅扩散;通风排烟系统能够有效降低烟气扩散速率,控制烟气扩散范围和沉降高度;针对此类结构车站站厅的防排烟设计,应综合考虑通风、出入口位置和空间构筑物对火灾烟气扩散的影响,确保火灾过程中人员疏散路径和楼扶梯处烟气层高度和烟气温度处于安全水平。 相似文献
547.
研究钢筋混凝土柱在升温、降温加热曲线作用下的截面温度场分布。完成了1根边长700mm方形钢筋混凝土柱的四面受火温度场试验,加热曲线升温段为ISO-834标准升温曲线,降温段为随炉冷却降温曲线。试验过程中测得了柱截面内不同位置的温度变化。建立有限元模型对试验结果进行了模拟分析。结果表明:方形柱截面内不同位置的升温速率、降温速率受其距受火面距离影响较大;截面内距离受火面越远的位置,升温滞后现象越明显;在ISO-834标准升温和随炉降温加热曲线作用下,当方形柱的截面边长大于等于700mm时,柱截面内的温度分布可反映大截面尺寸钢筋混凝土柱在火灾升、降温阶段的温度分布变化。 相似文献
548.
《组织行为杂志》2017,38(1):124-151
The Workplace Intergenerational Climate Scale (WICS) is designed to measure employees' attitudes and perceptions about workers of different ages in the workplace. In Study 1, an initial 18‐item measure was developed, reflecting five subscales: Intergenerational Contact, Workplace Intergenerational Retention, Positive Intergenerational Affect, Workplace Generational Inclusiveness, and Lack of Generational Stereotypes. Scores on the five WICS subscales were linked to workplace mentoring, opinions about older workers, and job satisfaction. In Study 2, the WICS items and subscales were further refined, and subscale relationships with similar constructs were explored via structural equation modeling. In Study 3, a more occupationally diverse sample was used to support criterion, incremental, discriminant, and external validity. Evidence supports the use of the WICS as a valid and reliable multidimensional measure of an organization's intergenerational climate. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
549.
550.
Yong Cui Shuming Liu Kate Smith Hongying Hu Fusheng Tang Yuhong Li Kanghua Yu 《环境科学学报(英文版)》2016,28(10):79-91
Stainless steels generally have extremely good corrosion resistance, but are still susceptible to pitting corrosion. As a result, corrosion scales can form on the surface of stainless steel after extended exposure to aggressive aqueous environments. Corrosion scales play an important role in affecting water quality. These research results showed that interior regions of stainless steel corrosion scales have a high percentage of chromium phases. We reveal the morphology, micro-structure and physicochemical characteristics of stainless steel corrosion scales. Stainless steel corrosion scale is identified as a podiform chromite deposit according to these characteristics, which is unlike deposit formed during iron corrosion. A conceptual model to explain the formation and growth of stainless steel corrosion scale is proposed based on its composition and structure. The scale growth process involves pitting corrosion on the stainless steel surface and the consecutive generation and homogeneous deposition of corrosion products, which is governed by a series of chemical and electrochemical reactions. This model shows the role of corrosion scales in the mechanism of iron and chromium release from pitting corroded stainless steel materials. The formation of corrosion scale is strongly related to water quality parameters. The presence of HClO results in higher ferric content inside the scales. Cl− and SO42 − ions in reclaimed water play an important role in corrosion pitting of stainless steel and promote the formation of scales. 相似文献