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31.
The present study assesses the feasibility of exploiting single- and double-basin solar stills in our daily lives. An investigation is carried out to determine the thermal performance and economic viability of making use of solar stills in water desalination. The climatic conditions of Tehran (35°44?N, 51°30?E) are considered to assess the feasibility of the basins. Transient energy and mass balance equations are utilized for modeling the thermal performance. The equations are solved by using fourth-order Runge–Kutta method in FORTRAN. The daily productivities of single- and double-basin solar stills are found to be 5.22 kg/m2 and 7.73 kg/m2, respectively, while the effect of different water masses (20–100 kg) on the productivity of each system was found to be optimum at 20 kg/m2. The results are compared with experimental work performed under different climatic conditions to examine the validity of the feasibility of basins in general. A life cycle cost analysis performed for Tehran, yields that single- and double-basin solar stills have savings-to-investment ratios of 4.2 and 4.8, respectively, indicating that they are economically feasible.  相似文献   
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One of the major reasons for desertification is unrestricted grazing leading to vegetation depletion, soil erosion and degradation, phenomena often considered irreversible in the short term. Here, we compare soil and biological parameters of degraded and conserved, recently rehabilitated arid shrubland in the Northern Negev, Israel. The study area was restored by conservation efforts including a strictly controlled grazing regime initiated in 1992. The visually recognizable improvement in the ecology of the restored shrubland is reflected in significant improvement in all examined biotic (herbaceous biomass, shrub patch density, and insect activity), and soil parameters (nutrients, organic matter content, moisture, and water infiltration). The difference is created predominantly by restoration of large biological patches composed of shrubs and other perennial plants often associated with ant or termite nests, where the most significant increases in productivity and soil quality were observed. In the conserved shrubland such patches covered 35 or 25 % of the area (in a normal and a drought year, respectively). In the degraded shrubland 5 % or less of the area was occupied by such patches that were much smaller and of lower biological complexity. With respect to plant biodiversity, six plant species were found only—and 18 others became significantly more common—in the rehabilitated area. The results of this article indicate that functional arid drylands can be restored within <16 years relying on strict conservation management with reduced grazing intensity.  相似文献   
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Prenatal diagnosis of 5p deletion syndrome, or cri du chat, following an abnormally low measurement of a screening of serum human chorionic gonadotrophin (hCG), is reported. Karyotyping following amniocentesis revealed a terminal deletion in the short arm of one chromosome 5. The pregnancy was electively terminated. 5p deletion syndrome has been described with abnormally high hCG levels and normal hCG levels. This is the first report of its association with abnormally low levels. The association between chromosomal abnormalities and hCG is discussed. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   
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Environmental Science and Pollution Research - Predictions of pore pressure and seepage discharge are the most important parameters in the design of earth dams and assessing their safety during the...  相似文献   
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Environmental Science and Pollution Research - This study aimed to investigate the effect of exposure to pesticides and the prevalence of type 2 diabetes (T2D). In a cross-sectional study with a...  相似文献   
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Journal of Material Cycles and Waste Management - Modeling of leaching process as a function of operational variables can specify an accurate perspective in the forecasting of valuable...  相似文献   
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Environmental Science and Pollution Research - Adopting methodologies utilizing exogenous data from ancillary stations for determining crop water requirement is a suitable approach to exempt local...  相似文献   
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