a well-known algorithm of clustering is k-means by which the data are divided into k classes based upon a distance criterion. in the present research, by using k-means method for classifying data derived from exploration boreholes in the parkam deposit, the optimum k has been calculated and then the data have been clustered and the relative geochemical behavioral characteristics analyzed. the c...

JULY 2012 50 High-temperature solder alloys are extensively used in dieattach, power semiconductor, and optical device packaging, flip-chip packaging, etc. Current industry standard solders for these applications are mainly high-lead solders (90–97 wt-% Pb) and gold-based eutectic solder alloys such as the 80Au20Sn solder. The die-attach process involves connecting the silicon die or chips to a...

Background: This research was investigated to evaluate effect of applying sunflower residues as a green manure on increasing zinc (Zn) concentration of two Iranian wheat cultivars in a Pb and cadmium (Cd) polluted soil. Methods: Treatments included the application of sunflower residuals grown in a Zn-polluted soil  at two levels of 0 and 8 t/ha, two wheat cultivars  in a soil contaminated with...

heavy metal contamination around the national iranian lead and zinc company (nilz) in zanjan province was evaluated in this paper. collected data were used to appraise the degree of soil contamination and also the source of pollution in the study area based on geoaccumulation index (igeo), and enrichment factor (ef). the levels of fe, zn, cd and pb in the samples exceed those reported in litera...

The chemically crosslinked metal-complexed chitosans were synthesized by using the ion-imprinting method from a chitosan with four metals (Cu(II), Zn(II), Ni(II) and Pb(II)) as templates and glutaraldehyde as a crosslinker. The influences of adsorption conditions, including molar ratios of crosslinker/chitosan and pH changes, were studied. They were used to investigate for comparative adsorptio...

Total concentrations and fractionation of Cu, Zn and Pb in seven operationally defined phases (exchangeable, carbonates, manganese oxides, organic complexes, amorphous iron oxides, crystalline iron oxides and residual) were determined in sediments colonised by the halophyte species Halimione portulacoides and Spartina maritima in a Tagus estuary salt marsh (Portugal). We aimed to determine whet...

The pollution characteristics of Pb, Cd, Zn, Cu and Ni in soil of lead−zinc mining area were studied. The results indicate that the contamination degree followed the sequence of Cd>Pb>Zn>Ni>Cu and concentrations of Pb, Cd and Zn exceeded corresponding limits of the Chinese National Soil Environmental Quality Standard III. The soil was extremely polluted by Cd (Iego=5.26), moderately to heavily ...

a field study was conducted around pb slag contaminated sites in ibadan, nigeria to assess theintake of trace metals by cows reared around the contaminated sites as indication of heavy metals contamination.levels of pb, cd, cu and zn in blood, milk and faeces were determined in 20 cows exposed to the sites and 20reference cows from uncontaminated areas. chemical analysis of pasture grasses and ...

during estuarine mixing of fresh water with saline water and due to the flocculation process, aportion of dissolved metals come into particulate phase, and the dissolved load decreases. this process plays an important role in self-purification of heavy metals in rivers. in this study, flocculation of cu, mn, ni, pb and zn during mixing of cheshme-kileh river water with caspian sea water has bee...

The aim of this study was to evaluate the aforementioned chemical elements in tibial plateau samples obtained during knee arthroplasty. The gender-specific analysis of chemical element levels in the bone samples revealed that there were statistically significant differences in the concentration of Pb and Se/Pb ratio. The contents of elements in the tibial plateau in the patients with osteoarthr...