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71.
Mohamed F. Yassin 《Environmental monitoring and assessment》2012,184(6):3749-3760
This paper presents a model for coupling the statistics of wind velocity distribution and atmospheric pollutant dispersion.
The effect of wind velocity distribution is modeled as a three-dimensional finite-impulse response (3D-FIR) filter. A phase
space representation of the 3D-FIR filter window is discussed. The resulting pollutant dispersion is the multiplication in
the phase space of the 3-D Fourier transform of the pollutant concentration and the volume described by the filter window
coefficients. The shape of the filter window in the phase space enables representing such effects as vortex shedding thermal
currents, etc. The impact of spatial distribution of the sensors on the resulting pollutant spatial distribution and the 3-D
FIR filter model employed also discuss. The case of a neutrally buoyant plume emitted from an elevated point source in a turbulent
boundary layer considers. The results show that wind turbulence is an important factor in the pollutant dispersion and introduces
expected random fluctuations in pollutant distribution and leads to spreading the distribution due to wind mixing. 相似文献
72.
73.
Giant reed for selenium phytoremediation under changing climate 总被引:1,自引:0,他引:1
Hassan R. El-Ramady Neama Abdalla Tarek Alshaal Ahmed S. Elhenawy Mohamed S. Shams Salah E.-D. A. Faizy El-Sayed B. Belal Said A. Shehata Mohamed I. Ragab Megahed M. Amer Miklós Fári Attila Sztrik József Prokisch Dirk Selmar Ewald Schnug Elizabeth A. H. Pilon-Smits Samia M. El-Marsafawy Éva Domokos-Szabolcsy 《Environmental Chemistry Letters》2015,13(4):359-380
74.
A high-performance liquid chromatography with photodiode array detector analytical method was developed to determine the residue levels of flusilazole in grape and investigate the dissipation pattern and safety. The results showed that the mean recoveries were in the range of 86%–90%. Limits of detection and quantification were 0.008 and 0.02 mg/kg, respectively. The residue levels of flusilazole were best described by first-order rate kinetics and with half-lives ranging from 4.2 days (recommended dose) to 4.6 days (double the recommended dose). In conclusion, flusilazole at the recommended or even at double the recommended doses does not pose any apparent hazards to consumers. 相似文献
75.
76.
Andrea Camperio Ciani § Loredana Martinoli Claudio Capiluppi † Mohamed Arahou ‡ and Mohamed Mouna‡ 《Conservation biology》2001,15(1):259-265
Abstract: The cedar oak forest of the Middle Atlas in Morocco is not only the last of the large forests in the southern Mediterranean, but it also contains all the surviving forest biodiversity. This forest has been severely affected by drought, overgrazing by mixed herds of goat and sheep, and excessive logging for timber, firewood, and livestock fodder. Recently, cedar bark stripping by Barbary Macaques ( Macaca sylvanus ) has begun to have an effect on the forest. We investigated this behavior by monitoring a 500-km2 mosaic forest of cedar and oak in the Middle Atlas of Morocco between 1994 and 1996. We surveyed the forest 18 times in four different seasons along a 90-km transect. We recorded observations of bark stripping and a variety of quantitative ecological factors that could predict this behavior, such as livestock density, forest quality, undergrowth condition, water availability, and monkey density. The statistical analysis (including rank correlation, regression, and nonparametric variance analysis) strongly suggests that water scarcity and monkey exclusion from previously available permanent water sources are correlated with intense cedar bark-stripping behavior by macaques. The density of cedars and of monkeys appeared to be only secondary factors. As a conservation policy, making water more accessible to wild monkeys might reduce bark-stripping behavior. 相似文献
77.
The delafossite CuCrO2 elaborated by sol-gel from 40 nm diameter colloid is optically active in the visible region. It is characterized physically and photoelectrochemically. The microstructure is fairly homogenous with a mean crystallite size of ca. 2 μm. The optical gap (1.30 eV), determined from the diffuse reflectance, is well suited to the sunlight spectrum. The Mott Schottky plot is characteristic of P-type conductivity with a flat band potential of -0.26 VSCE. As application, the photoreduction of chromate is successfully achieved in air-equilibrated suspension CuCrO2/ZnO (1/1). CuCrO2 is photoactivated by visible light and the electrons in the conduction band (-1.34 VSCE) are injected to ZnO. In the presence of salicylic acid, a conversion of Cr(VI) to Cr(III) of 57% is obtained under optimal conditions (pH 3 at 25℃, 5×10-4 mol/L) because of the HCrO4- dark adsorption onto ZnO (4HCrO4- + 3C7H6O3 + 18O2 + 16H+ → 4Cr3+ + 21CO2 + 19H2O, ΔG0 = -557 kcal/mol). Prolonged illumination is accompanied by a deceleration in the photoactivity owing to the competitive water reduction, an issue of energetic concern. The hetero-system exhibits self sensitization for hydrogen production with an evolution rate of 149 μmol/(hr·g). 相似文献
78.
The distribution of Cd, Cu, Fe, Hg, Mn, Ni, Pb, and Zn concentration in five algae species (Enteromorpha intestinalis, Enteromorpha linza, Ulva lactuca, Corallina mediterranea, Pterocladia capillacea) collected from three areas having different types of metal contamination along Alexandria coastal waters (Egypt) were determined by Atomic Absorption Spectrometry. The recovery study was carried out using a Certified Reference Material TORT-2. The obtained heavy metal contents indicate that different species demonstrate various degree of metal accumulation. Enteromorpha intestinalis (green algae) recorded the highest levels of Fe and Mn while Corallina mediterranea (Calcareous red algae) recorded the highest concentration of Pb, Ni, and Cd in the three areas under study. According to the present study, filamentous algae (Enteromorpha intestinalis) showed the ability to concentrate greater amount of trace elements than the foliaceous ones (Enteromorpha linza). In each area, mercury concentration has nearly the same value for all species under study. 相似文献
79.
The effect of the microbial flora of municipal sewage, with special reference to faecal coliform and faecal streptococci groups, on the hydrocarbons biodegradation of the refinery wastewater from the Moustorod Oil Refinery has been studied. The results indicate that sewage with its microbial flora seems to have a significant role in the biodegradation of hydrocarbons in refinery wastewater. In addition, the early degradation in the wastewater seeded by sewage reveals that faecal streptococci, in addition to other microbial flora, have a significant role in the biodegradation of hydrocarbons. 相似文献
80.
Mohamed A. Shreadah Tarek O. Said Alaa M. Younis Rabie S. Farag 《Chemistry and Ecology》2006,22(5):395-404
Organotin compounds were measured in sediments of four different semi-closed areas of the Mediterranean coast of Alexandria: the Eastern Harbour, Western Harbour, El-Max Bay, and Abu-Qir Bay. Due to the commercial trade activity inside the Western Harbour, in addition to the effect of wastes discharged from El Noubaria canal, it shows the highest concentrations of total tin (6.34 μg g-1 dry weight), dibutyl tin (1.63 μg g-1 wet weight), tributyl tin (0.33 μg g-1 wet weight) and diphenyl tin (1.06 μg g-1 wet weight) compared with other locations. The concentrations of TBT species showed the highest contents compared with DBT and DPhT compounds in all sampling areas. This trend might be due to the worldwide use of TBT not only as biocides in antifouling paints but also as preserving agents for wood, fungicides in agricultural activities, and heat and UV stabilizers of PVC, which results in a direct release of TBT into the water body, accumulation in aquatic fauna. There is also precipitation into sediments and a decrease in degradation rate into its derivatives. Variations, types, concentrations, and distribution of different organotin compounds are discussed in the areas under investigation. The study reveals a new record of organotin compounds along the Alexandria coast and makes comparisons with other surrounding areas of interest. 相似文献