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Scale environmental heterogeneity

The issue of spatio-temporal scaling is far from resolved but we postulate that from an evolutionary viewpoint at local geographic scales where dispersal limitations are minimal, environmental heterogeneity is the major driver of diversity over time. Across larger distances the effects of dispersal limitation become more... [Pg.39]

Quantifying adsorption of contaminants from gaseous or liquid phases onto the solid phase should be considered valid only when an equilibrium state has been achieved, under controlled environmental conditions. Determination of contaminant adsorption on surfaces, that is, interpretation of adsorption isotherms and the resulting coefficients, help in quantifying and predicting the extent of adsorption. The accuracy of the measurements is important in relation to the heterogeneity of geosorbents in a particular site. The spatial variability of the solid phase is not confined only to field conditions variability is present at all scales, and its effects are apparent even in well-controlled laboratory-scale experiments. [Pg.95]

Why adsorption, ion exchange and heterogeneous catalysis in one book The basic similarity between these phenomena is that they all are heterogeneous fluid-solid operations. Second, they are all driven by diffusion in the solid phase. Thus, mass transfer and solid-phase diffusion, rate-limiting steps, and other related phenomena are common. Third, the many aspects of the operations design of some reactors are essentially the same or at least similar, for example, the hydraulic analysis and scale-up. Furthermore, they all have important environmental applications, and more specifically they are all applied in gas and/or water treatment. [Pg.604]

Populations and communities integrate the effects of environmental conditions over different temporal and spatial scales. Natural communities are characterized as being spatially heterogeneous and temporally dynamic systems (Connell and Sousa 1983 Sousa 1984), and populations may show a high degree of stochastic... [Pg.187]

Semiconductor particles and films have been found to act as heterogeneous photocatalysts in a number of environmentally important reactions. Materials such as Ti02 and CdS have been found to be efficient in laboratory-scale pollution abatement systems, reducing both organic and inorganic pollutants/impurities to harmless species (see [1-35] and references therein). Photocatalysts have been shown to be useful for decomposition of O3 [36], destruction of bacteria [37-39] and viruses [40], purification of air [41], photosplitting of water [42,43] and clean-up of oil spills [44,45]. Photocat-... [Pg.452]


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Heterogeneity environmental

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