نتایج جستجو برای: bod5 showed higher levels than these standards in some stations
تعداد نتایج: 17318148 فیلتر نتایج به سال:
data envelopment analysis (dea) is a powerful tool for measuring relative efficiency of organizational units referred to as decision making units (dmus). in most cases dmus have network structures with internal linking activities. traditional dea models, however, consider dmus as black boxes with no regard to their linking activities and therefore do not provide decision makers with the reasons...
fluorescence chemical sensors for the highly sensitive and selective determination of pb2+ , hg2+, co2+ and fe3+ ions in aqueous solutions are described. the ion sensing system was prepared by incorporating lipophilic ligand (l) as a neutral ion-selective fluoroionophore in the plasticized pvc membrane containing sodium tetraphenylborate or potasium tetrakis (p-chlorophenyl) borate as a liphoph...
aquatic organisms are one of most important human food sources but they can accumulate heavy metals entered aquatic ecosystems in their tissues and organs same time and can be transferred through the food chain to higher food levels and in the most top into the human body. shrimps are of the main groups of sea foods; and because they are benthic species, they can absorb high concentrations of h...
Background and Objective: Noise pollution is an important environmental problem that may cause hazardous effects, such as hearng loss, sleep disorders, hypertension and digestive problems in communities. To prevent these effects, achieving recommended standards of noise pollution measuring in cities is mandatory. This study was aimed to evaluate noise pollution in zanjan city in 2007. Materials...
abstract: advertisements are the most accessible type of authentic materials, and this is one reason why they are used more and more in english teaching classes. for this cause, studies in the field of advertisements are very widespread nowadays. for pun is one aspect which makes advertisements more interesting, it is used more than before in advertisements. use of puns makes an advertisement m...
Measurement of chlorophyll-a can be considered important to investigate the primary production of an ecosystem. This study aimed to investigate chlorophyll-a concentration, primary production and the factors affecting them in Shadegan Wetland located in Khouzestan Province - Iran. Sampling for measuring (NO3, PO4, BOD5, DO, pH, EC, salinity, temperature) was performed seasonally at five samplin...
The largest river in the southern basin of the Caspian Sea is Sefidroud, and the most important native fish of that river is the large head sea bass. Due to its long route and passing through different areas, this river is exposed to various contaminants including heavy metals. The aim of this research was to investigate the amount of bioaccumulation of lead and nickel heavy metals in L. capito...
Rainbow trout (Oncorhynchus mykiss) is one of the most-widely cultivated cold fresh water fish in the world. Gamasyab River, with a length of about 200 Km, is one of the longest rivers of Iran. The aim of this research is to determine the effects of trout farm effluents on this river water. From a total of 24 trout farms in the area, four farms were randomly selected and three sampling statio...
learning a second or foreign language requires the manipulation of four main skills, namely, listening, reading, speaking, and writing which lead to effective communication. it is obvious that vocabulary is an indispensible part of any communication, so without a vocabulary, no meaningful communication can take place and meaningful communication relies heavily on vocabulary. one fundamental fac...
anzali international wetland is one of the most valuable water resources as registered in ramsar convention with an extent of about 150 km2 in the south caspian sea. this wetland, not only has ecological and biological importance for migratory birds and rare fish species, but also is used for farms to discharge into the caspian sea through this wetland. therefore its pollution control is very i...
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