نتایج جستجو برای: rivers and other natural resources
تعداد نتایج: 16930682 فیلتر نتایج به سال:
In this paper a concept of an integrated water quality model for a river catchment area is presented. The main focus is directed to the development of a water quality module for rivers. Necessary simplifications for calculation of hydraulics and water quality will be explained. Furthermore, by first simulation results possible applications of the model are presented.
abstract in aggregate, active forms of reactive silica with mineral names are sometimes associated with sand and gravel in concrete mixture. alkali hydroxides originated from alkalis in the cement or other resources form an alkaline silica gel with this reactive silica which becomes swallowed and expanded during time causing damage to concrete. there have been growing researches on alkaline r...
Background and Objectives: Natural organic matters (NOMs) are abundant in natural water resources and in many ways may affect the unit processes in water treatment. Although NOMs are considered harmless but they have been recognized as disinfection by-products (DBPs) precursors during the chlorination process. Formation of DBPs highly depends on the composition and concentration of NOMs. The ob...
the aim of this paper is eliminating cr(vi) by natural hap. hap is a inexpensive material which is used from bovine critical bone ash in order to remove heavy metal ions like cr(vi). some experiments in different ph are performed (ph=2,3,7). maximum adsorption was appeared at ph=2, dosage=0.3 gr, c0=10 mg/l. cr(vi) removal depends on ph value and initial amount of cr(vi) result of experiments w...
water resources suitability is one of the most important factors to sustainabilityutilization of natural potential by rangeland grazing suitability. to determine this factor inshort time, low cost and high accuracy are most challenges of experts and ranchers. usingsuitable technique for this subject can be sustainable utilization comprising from rangelandecosystems according to its degradation ...
development projects in natural water resources like rivers and lakes, specially transferring water to use in agriculture, domestic and industrial sector without considering environmental values, causes irrecoverable and irreversible damage to ecosystem and future options. if we consider the future generation and species rights, those damages and costs can be very much than we take in. the abov...
One of the most powerful ways to develop hypotheses regarding the biological functions of conserved genes in a given species, such as humans, is to first look at what is known about their function in another species. Model organism databases and other resources are rich with functional information but difficult to mine. Gene2Function addresses a broad need by integrating information about conse...
South Africa has a wide range of soils and climates. Extensive studies, especially over the past 25 years, have been conducted into practices and systems which could conserve the soil, water, energy and other resources required for sustainable crop production under various of these soil and climate combinations. Some of the results obtained and ongoing or envisaged work is outlined. It is hypot...
Groundwater is essential to modern human survival during drought periods. There is also growing geological evidence of springs associated with stone tools and hominin fossils in the East African Rift System (EARS) during a critical period for hominin evolution (from 1.8 Ma). However it is not known how vulnerable these springs may have been to climate variability and whether groundwater availab...
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