نتایج جستجو برای: pollution index pi
تعداد نتایج: 502762 فیلتر نتایج به سال:
in this paper, at first we mention to some results related to pi and vertex co-pi indices and then we introduce the edge versions of co-pi indices. then, we obtain some properties about these new indices.
topological indices are numerical parameters of a graph which characterize its topology. inthis paper the pi, szeged and zagreb group indices of the tetrameric 1,3–adamantane arecomputed.
High concentrations of heavy metals in street dust are considered to be a serious risk to the human health and the environment. In this study, 30 dust samples were collected from the pavements in the main streets of Abadan to determine the level of pollution of heavy metals in the street dust. Heavy metal concentrations were analyzed by inductively coupled spectroscopy (ICP-OES) method. The lev...
the sadhana index (sd) is a newly introduced cyclic index. efficient formulae for calculatingthe sd (sadhana) index of linear phenylenes are given and a simple relation is establishedbetween the sd index of phenylenes and of the corresponding hexagonal sequences.
This study aimed to investigate the risk of element/heavy metal pollution caused by listvenitization. In this context, heavy listvenite-derived soils in region where listvenitized ultrabasic rocks are present as a result hydrothermal alterations vicinity Alakeçi (Bayramiç Çanakkale/Western Türkiye) was investigated with index, geoaccumulation index and integrated parameters. For purpose, Cu, Zn...
Background and Objective: Street dust is considered as one of the important sources of particulate matters and heavy metals in the atmosphere. The goal of this study was to assess the heavy metals pollution in street dust of Tehran and evaluate their ecological risk. Materials and Methods: The sampling of street dust was carried out in two areas at the east and west of Tehran. After preparatio...
Background and Objective: Today, soil and water pollution with heavy metals is one of the major challenges around the world. The aim of this study is to investigate the contamination of soils around a lead and zinc mine. Materials and Methods: In the summer of 2019, 100 soil samples were taken from the mine vicinity and the characteristics of texture, acidity, salinity, calcium carbonate, orga...
The objective of this study was to investigate the concentration and spatial distribution patterns of six potentially toxic heavy metal elements (Mn, Zn, Cr, Pb, Cu and Ni) in bus station dusts in the Xifeng district of Gansu province, NW China. The contents were analyzed for Mn, Zn, Cr, Pb, Cu and Ni by using S8 TIGER Brochures wavelength dispersive X-ray fluorescence spectrometry. Geoaccumula...
let g and h be two graphs. the corona product g o h is obtained by taking one copy of gand |v(g)| copies of h; and by joining each vertex of the i-th copy of h to the i-th vertex of g,i = 1, 2, …, |v(g)|. in this paper, we compute pi and hyper–wiener indices of the coronaproduct of graphs.
در سالیان اخیر پدیده حزن انگیز گرد و غبار گاها آسمان غرب ایران را اشغال کرده و زندگی مردم را تحت تاثیرات زیانبار خود قرار داده است. پدیده گرد و غبار که به عنوان مهمترین معضل زیست محیطی کشور در دهه اخیر قلمداد می شود واجد طیف وسیعی از خسارات و اثرات منفی است که باعث گردیده این موضوع از یک شکل محلی به بحرانی بین المللی تبدیل شود. این پایان نامه به مقایسه خصوصیات فیزیکوشیمیایی ذرات گرد و غبار در...
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