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61.
A comprehensive, GIS‐based modelling approach is developed to estimate runoff and phosphorus transport within a watershed at a daily time step. The approach relies on the use of GIS data for deriving major critical model parameters that exhibit distinct spatial variability over the catchment. Surface runoff is calculated by a modified rational method, which depends upon rainfall intensity, soil moisture status, slope, land‐use and soil characteristics. Phosphorus loading is estimated as a function of the runoff volume and the event mean concentration for different land use categories. A diffusive approximation method is used to trace runoff and phosphorus transport to the basin outlet. The modelling approach is tested in the Margecany catchment, Hornad River basin, Slovakia, to simulate runoff, phosphorus loading, and its transport on a daily time scale using data observed between 1995 and 2000. Satisfactory results of the hydrographs and phosphorus concentration at the basin outlet are obtained, though more efforts regarding the phosphorus cycling and its biochemical reactions need to be clarified by further research. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
62.
63.
The in situ measurement of dynamic changes in viscosity induced by illumination has been performed on a range of photosensitive urethane dimethacrylates (UDMA) evaluating the response at three different illuminations intensities (1, 2, and 5 W cm?2) and at three different diluent concentrations (15, 30, and 50%), using 1,6‐hexanediol dimethacrylate (HDDMA). The initial viscosity value ranged between 1 and 10 Pa s for the mixtures with final viscosities approaching 1 × 107 Pa s after illumination. The initial rise in viscosity was analyzed using an exponential model with an exponent ranging from 1.0 to 2.5 with time under exposure. Higher conversion rates were observed with both higher intensity and lower HDDMA content. The analytical approach taken here could aid in developing more sophisticated models that consider simultaneous flow and cure advancement in other thermosets. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 相似文献
64.
In this work, we co‐formulated an oil‐borne copper naphthenate/permethrin wood preservative system with synthetic polymer‐based fire‐retardant additives prior to the impregnation of Pinus radiata sapwood. We evaluated what effect, if any, the preservative had upon the fire performance properties of the fire retardants and whether the fire retardants impacted on the fungicidal and termiticidal efficacy of the preservative. The fire retardants included halogenated and phosphorus‐based systems. A mass loss calorimeter, in conjunction with a thermopile, was used to measure the time to ignition and the peak heat release rate (PHRR) from which the fire performance index (FPI) was determined. The preservative properties were evaluated using termite and soil‐block decay bioassays. In summary, we found that the rate of fire growth was reduced when the fire retardants were used in combination with the wood preservative. We also found that the PHRR was a better determinant of fire performance than the FPI. The performance of the wood preservative was enhanced against fungal decay and termite attack when used in combination with the fire retardants. The fire retardants also demonstrated some wood preservative properties of their own. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
65.
66.
Nutrient availability has long been considered one of the most important factors regulating production of benthic algae in oligotrophic rivers; yet, empirical relationships do not have as wide an application as similar models derived for lentic systems. The aim of this research was to derive empirical relationships between nutrient concentrations and benthic algal abundance and to identify commonalities with other studies to improve our understanding of constraints on algae in oligotrophic rivers. Surveys of physical, chemical and biological attributes of oligotrophic mountain rivers in spring, summer and autumn for 2 years confirmed that small amounts of anthropogenic phosphorus (0.1–5.6 µg/L total phosphorus (TP)) resulted in 4‐ to 30‐fold increases in abundance of benthic algae and benthic macroinvertebrates (BMIs). Algal accrual along a gradient in nutrient availability was not masked by grazing pressure but was positively correlated with abundance of scrapers. Epilithic abundance was highest downstream of anthropogenic nutrient sources in autumn. We concluded that benthic algal abundance in these mountain rivers was weakly correlated with phosphorus availability if light was not limiting but ultimately controlled by temperature and river discharge. Therefore, we recommend more direct measures of nutrient limitation be used to predict changes in ecological integrity at the lower end of the resource gradient. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
67.
Separations through reactions can provide reliable and economically viable alternatives to established methods of separation,
particularly for close boiling substances. New strategies in ‘Dissociation Extraction’ and ‘Dissociation Extractive Crystallization’
for separation of close boiling acidic/basic mixtures have been highlighted. Separations with aqueous solutions of hydrotrope
and aqueous micellar solutions have been brought out. Separations by membranes with facilitated transport is potentially attractive.
This paper is dedicated to Dr L K Doraiswamy on his sixtieth birthday. 相似文献
68.
速溶奶粉中卵磷脂含量的测定 总被引:10,自引:1,他引:9
叙述了速溶奶粉中卵磷脂的测定方法,样品通过一系列处理后,测定其磷含量,回收率为96% ̄98%。 相似文献
69.
D.M. LEWIS 《International journal of cosmetic science》1996,18(3):123-135
The strength and nature of dye–fibre interactions vary according to fibre type and dye type. In the case of acid dyes for polyamide fibres, cationic dyes for acrylic fibres, disperse dyes for hydrophobic fibres, and direct dyes for cellulosic fibres, these interactions may be classified as non-covalent, a classification which includes van der Waals (VDW), electrostatic, induction, solvophobic and charge-transfer interactions.
Reactive dyes are a notable exception to the above, since the interaction which is responsible for their excellent wet fastness is the dye–fibre covalent bond, however, these dyes are increasingly viewed as environmentally unfriendly due to high salt usage and residual unfixed colour. This situation may be improved by either incorporating amine sites in the cellulose or by reversing the system to incorporate reactive residues in the fibre and nucleophilic sites in the dye.
Nonionic disperse dyes are valuable for hydrophobic fibres such as polyester but have made little impact on hydrophilic fibres such as silk, wool and cotton. Experiments to develop simple treatments to render the latter fibres disperse dyeable are described and the combined role of solvophobic and – interactions discussed. 相似文献
Reactive dyes are a notable exception to the above, since the interaction which is responsible for their excellent wet fastness is the dye–fibre covalent bond, however, these dyes are increasingly viewed as environmentally unfriendly due to high salt usage and residual unfixed colour. This situation may be improved by either incorporating amine sites in the cellulose or by reversing the system to incorporate reactive residues in the fibre and nucleophilic sites in the dye.
Nonionic disperse dyes are valuable for hydrophobic fibres such as polyester but have made little impact on hydrophilic fibres such as silk, wool and cotton. Experiments to develop simple treatments to render the latter fibres disperse dyeable are described and the combined role of solvophobic and – interactions discussed. 相似文献
70.
David C. Whitehead Katherine M. Goulden Roy D. Hartley 《Journal of the science of food and agriculture》1985,36(5):311-318
The distribution of 10 nutrient elements was assessed in three fractions of herbage samples of perennial ryegrass, tall fescue, white clover and lucerne. The cell wall fraction, prepared by mechanical disintegration of undried material, contained the following proportions of the total herbage content of the major elements: N, 2.9–16.4%; P, 3.0–6.9%; S, 3.6–17.2%; Ca, 11.3–51.8%; Mg. 6.4–27.6% and K, 0.1–1.7%. Substantial though more variable proportions of the trace element cations, Fe, Mn, Zn and Cu were also present in the cell wall fraction. The extent to which the elements were soluble in water was assessed by analysis of the water-insoluble fraction prepared from freeze-dried samples of each herbage. The proportions of the total herbage content of the major elements soluble in water were: N, 30–57%; P, 80–92%; S, 35–71%; Ca, 48–69%; Mg. 65–83% and K, 90–96%. With the trace element cations the proportions soluble in water were more variable, though they were generally less than 70% of the total. The extent to which the various elements were soluble in 80% aqueous ethanol was assessed by analysis of the insoluble fraction prepared from freeze-dried materials. With each of the major elements, smaller proportions of the total herbage content were soluble in 80% ethanol than in water, which may reflect in part the lower solubility of proteins and pectin. With the trace element cations, the differences in solubility between 80% ethanol and water were generally small and inconsistent. 相似文献