Variability source

In watersheds where surface runoff is limited by infiltration rate rather than soil-water storage capacity, areas of the watershed can alternate between sources and sinks of surface flow. This again will be a function of soil properties, rainfall intensity and duration, and antecedent moisture condition. As surface runoff is the main mechanism by which phosphorus is exported from most watersheds, it is clear that, if surface runoff does not occur, phosphorus export can be small. Thus, consideration of hydro-logic pathways and variable source areas is critical to a more detailed understanding of phosphorus export from agricultural watersheds. 

Depending on the source of the graphite, one obtains distinctly different IR/PA spectra (frequently caused by adsorbed species) and the response of the DTGS detector of an IR spectrometer turns out to be a more accurate measure of variable source intensity (12). A normalization technique (13) requiring measurement of the spectrum at two different mirror velocities and corrected by black body spectra taken at the same two velocities appears to be the best normalization method reported thus far. 

Duhamel s principle can be extended to cases of surface conditions being functions of both time and space variables and to variable source and sink terms as well (Zwillinger, 1989). 

Arguably, given its immediate and direct impact on public health, the pharmaceutical industry has additional reasons to achieve a higher level of technological execution where product quality is assured by effective automated systems and where variability sources are understood and minimized. Even removing this motivation, this industry should embrace model-based optimization enthusiastically, since it has reduced cost and accelerated product development across many other industries. 

Risk-based orientation Regulatory scrutiny based on the level of scientific understanding Mechanistic basis for understanding failure modes and variability Sources of variability and risk to quality Drive out fear Continuous improvement— Change control and life cycle management... 

The electrodes are connected to a suitable variable source of direct current (Note 6), the magnetic stirrer is started, and a potential of about 50 volts is applied. This results in a current flow of 1-2 amperes. The solution soon comes to boiling the voltage is then regulated so that a rapid reflux is maintained (Note 7). 

The mixture10 of diphosphorus tetraiodide and white phosphorus is introduced into flask A of the apparatus, which has been previously swept with carbon dioxide. This flask is constructed so as to fit a Glas Col spherical heating mantle which enables even heating. The connections between flask A and the condenser and between the condenser and flask B are wrapped in electrical heating tape which is connected to a variable source of power. 

When evaluating the health effects of barium compounds, it is important to keep in mind that different barium compounds have different solubilities in water and body fluids and therefore serve as variable sources of the Ba + ion. The Ba + ion and the soluble compounds of barium (notably chloride, nitrate, hydroxide) are generally highly toxic to humans and experimental animals. The insoluble barium compounds (notably sulfate and carbonate) are inefficient sources of the Ba + ion and therefore are generally nontoxic. Throughout the following section (2.2), the health effects by route of exposure of both soluble and insoluble barium compounds are discussed. 

The decompositions of bromobenzene [717] and chlorobenzene ions [716] have been studied by the special PIPECO experiment using variable source residence times. In the case of chlorobenzene, increasing the residence time from 0.7 to 8.9 ps resulted in a shift (kinetic shift) in the breakdown curves by 0.4 eV. Detailed analysis of the effects of varying residence time provided information on the k(E) vs. E curve in the vicinity of 104—106 s-1. The k(E) vs. E curve obtained differed significantly [by almost an order of magnitude in k(E) at some energies] from the curve reported in the earlier PIPECO study of metastable ions [22], The initial analysis [716] placed the critical energy for chlorine loss at 3.40 0.05 eV, but this has subsequently been revised to 3.19 0.02 eV [717]. The transition state was found to be loose . 

PIPECO with variable source residence time has been applied to benzonitrile [718] and the k(E) vs. E curves derived were in agreement with those in the earlier PIPECO study [278]. The kinetic shift observed on increasing the residence time from 1.07 to 6.90/is was about 0.4 eV. Analysis of the results led to a critical energy of 3.015 eV and indicated a tight transition state. 

Renewable electrolysis can help overcome one of the key barriers to realizing a hydrogen based economy by replacing the carbon intensive one that exists today. There is an excellent opportunity for research in renewable hydrogen production both in terms of understanding the operation of the electrolyzer under variable sources and optimizing, in terms of efficiency, cost, and robustness, the link between a renewable source and electrolyzer stack. 

Green D. H., Falloon T. J., and Taylor W. R. (1987) Mantle-derived magmas—roles of variable source peridotite and variable C-H-O fluid compositions. In Magmatic Processes and Physicochemical Principles, Geochemical Society Special Publication No. 1 (ed. B. O. Mysen). Geochemical Society, Universtiy Park, PA, pp. 139-154. 

Hirschmann M. M., Ghiorso M. S., and Stolper E. M. (1999b) Calculation of peridotite partial melting from thermodynamic models of minerals and melts 11. Isobaric variations in melts near the solidus owing to variable source composition. J. Petrol. 40, 297-313. 

For file periodic case, we just change the definition of file dimensionless time variable source term, as follows for the parallel-plates geometry ... 

Soil structure, geologic strata, and topography influence the location and movement of variable source areas of surface runoff in a watershed. Eragipans or other layers, such as clay pans of distinct permeability changes, can determine when and where perched water tables occur. Shale or sandstone strata also influence soil moisture content and location of saturated zones. For example, water will perch on less permeable layers in the subsurface profile and become evident as surface flow or springs at specific locations in a watershed. Converging topography in vertical or horizontal planes, slope breaks, and hill slope depressions or spurs, also influence... 

Calcite-cemented intervals are heterogeneously distributed within the field. They are a few metres thick, with lateral extents no greater than a few kilometres. The amount of Ca necessary to form the <1% calcite present in the reservoir is small and compatible with either internal or external sources. The exact source of Ca could not be pinpointed, nor could the mechanism of reconcentration in specific intervals. REE compositions of calcite samples, however, suggest that trace elements originated from local and variable sources, and support the prevalence of relatively closed conditions during calcite cementation. 

There are many equations which allow calculation of sediment transport rate within a water body, or sediment flux (see for example Task Committee of Computational Modeling of Sediment Transport Processes, 2004 for a review). However, these equations tend to be for a uniform sediment distribution, which is far from the variable source supply of material seen in events when the majority of sediment is moving. It is also generally considered that a particular flow has a maximum capacity to transport sediment, although the concentration this relates to depends again on sediment characteristics. Hence tliere are examples in China where sediment concentrations can reach several tens of thousands of parts per million for very fine particles, whereas a flow may become saturated with sand-sized particles at far lower concentrations. Rivers are often considered to be either capacity- or supply-limited in terms of their sediment transporting dynamics. However, in practice for most rivers, most of the time, sediment transport is limited by a complex and dynamic pattern of sediment supply. 

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