CHEMICAL COMPOSITION OF THE SURFACE LAYER OF BOTTOM SEDIMENTS IN THE NORTHERN PART OF THE CHOTT EL JERID PERIODIC LAKE IN TUNISIA

Author(s):  
Robert Machowski
2019 ◽  
Vol 47 (5) ◽  
pp. 26-51
Author(s):  
V. V. Gordeev ◽  
N. V. Kozina ◽  
G. N. Baturin

Atomic absorption determinations of a group of heavy metals (Cu, Zn, Ni, Co, Cr, Pb, Fe, Mn) in 190 samples of surface bottom sediments of the Middle and Southern Caspian Sea that were sampled by crab in middle of XX century (the collection of G.N. Baturin) and in 30 samples of recent sampling by grab also (2012–2015) were carried out. The aim of the investigations was to construct the schematic maps of heavy metal distribution in bottom sediments of both parts of the Caspian Sea on the materials of a half of century prescription that may serve as a base for comparison with the data of recent researches in frameworks of the program “The Caspian Sea System” under leadership of academic A.P.Lisitzin from 2012 till present time. The comparison between chemical composition of old and new sediment samples was realized, their similarities and divergences were revealed and probable reasons of divergences were presented. The maps of distribution of several metals (Fe, Mn, Co, Cr) are submitted together with necessary for interpretation maps of CaCO3, Corg and some other. It was shown that the structure of maps for all metals investigated was very similar because all these metals had concern to the group of iron.


2004 ◽  
Vol 6 (2) ◽  
pp. 186-198
Author(s):  
G. K. Khursevich ◽  
A. V. Kudelskiy ◽  
S. A. Fedenya ◽  
J. Marphy

2017 ◽  
Vol 22 (1) ◽  
pp. 81-103 ◽  
Author(s):  
Nataliya Michailovna Kalinkina ◽  
Natalya Alexandrovna Belkina ◽  
Anastasiya Ivanovna Sidorova ◽  
Nataliya Alekseevna Galibina ◽  
Kseniya Mikhailovna Nikerova

2019 ◽  
Vol 91 (2) ◽  
Author(s):  
Paweł Widomski ◽  
Zbigniew Gronostajski ◽  
Marcin Kaszuba ◽  
Jagoda Kowalska ◽  
Mariusz Pawełczyk

In response to the growing need to use wear-resistant layers that increase durability of tools in forging pro-cesses, hybrid layers have been proposed that combine hardfacing with nitriding treatment. This article presents the results of laboratory tests of surface wear-resistant layers made with a new hybrid technology Gas-Shielded Metal Arc surfacing (hardfacing) with ZeroFlow gas nitriding. Specimens made with hardfacing or nitriding were prepared and examined. Analysis covered the thorough microstructure study, EDX chemical composition analysis and microhardness analysis. In experiment, 3 different types of nitrided layers were proposed for alpha, gamma prim and epsilon nitrides in the surface layer. The results of metallographic research in the surface layer was presented. The analysis of chemical composition in the particular overlay welds was performed to determine the content of alloying elements in the particular overlay welds. The susceptibility to nitriding of used weld materials as well as the ability to form particular types of nitrides on selected welded substrates was also tested.


2019 ◽  
Vol 57 (11) ◽  
pp. 1213-1220
Author(s):  
N. V. Kuzmenkova ◽  
V. V. Krupskaya ◽  
E. V. Duriagina ◽  
I. N. Semenkov ◽  
S. E. Vinokurov

2012 ◽  
Vol 12 (4) ◽  
pp. 207-212 ◽  
Author(s):  
Daniel Szymański ◽  
Julita Dunalska ◽  
Michał Łopata ◽  
Izabela Bigaj ◽  
Rafał Zieliński

AbstractThe aim of this study was to determine the chemical composition of Lake Widryńskie bottom sediments (max. depth. 27.0 m, area 123.9 ha). The sampling of bottom sediments was conducted once, on 16 August 2010. Sampling was made in 10 specific areas. Among the 10 samples, 4 samples were taken from the littoral and sublittoral zones, while the rest were taken from the profundal zone. The dominant component of the sediments was silica and calcium carbonates were subdominant. Based on the survey, it was determined that silica occurred in greater numbers in littoral sediments, while in sublittoral sediments there was increased participation in the chemical composition of organic matter. The elements that build a capacity complex were a small percentage of the dry weight of sediment. Sediment from the vicinity of inflows contains higher amounts of silica, which confirmed the impact of the catchment on the chemical composition of sediments.


2007 ◽  
Vol 48 (11) ◽  
pp. 886-900 ◽  
Author(s):  
T.V. Pogodaeva ◽  
T.I. Zemskaya ◽  
L.P. Golobokova ◽  
O.M. Khlystov ◽  
H. Minami ◽  
...  

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