Aleksei Nikitenkov

Dr. Aleksei Nikitenkov

Tomsk polytechnic university

Research Focus & Metrics

Academic Career Length

13Years (2014-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 November 2017 in Journal of Environmental Radioactivity
Verified
Journal Article
Open access
EDEkaterina M. Dutova
Ekaterina M. Dutova
ANAleksei Nikitenkov
Aleksei Nikitenkov
VPVitaly D. Pokrovskiy
Vitaly D. Pokrovskiy
DBDavid Banks
David Banks
BFBjørn S. Frengstad
Bjørn S. Frengstad
VPValerii P. Parnachev
Valerii P. Parnachev
Generic hydrochemical modelling of a grantoid-groundwater system, using the Russian software "HydroGeo", has been carried out with an emphasis on simulating the accumulation of uranium in the aqueous phase. The baseline model run simulates shallow granitoid aquifers (U content 5 ppm) under conditions broadly representative of southern Norway and southwestern Siberia: i.e. temperature 10 °C, equilibrated with a soil gas partial CO2 pressure (PCO2, open system) of 10-2.5 atm. and a mildly oxidising redox environment (Eh = +50 mV). Modelling indicates that aqueous uranium accumulates in parallel with total dissolved solids (or groundwater mineralisation M - regarded as an indicator of degree of hydrochemical evolution), accumulating most rapidly when M = 550-1000 mg L-1. Accumulation slows at the onset of saturation and precipitation of secondary uranium minerals at M = c. 1000 mg L-1 (which, under baseline modelling conditions, also corresponds approximately to calcite saturation and transition to Na-HCO3 hydrofacies). The secondary minerals are typically "black" uranium oxides of mixed oxidation state (e.g. U3O7 and U4O9). For rock U content of 5-50 ppm, it is possible to generate a wide variety of aqueous uranium concentrations, up to a maximum of just over 1 mg L-1, but with typical concentrations of up to 10 μg L-1 for modest degrees of hydrochemical maturity (as indicated by M). These observations correspond extremely well with real groundwater analyses from the Altai-Sayan region of Russia and Norwegian crystalline bedrock aquifers. The timing (with respect to M) and degree of aqueous uranium accumulation are also sensitive to Eh (greater mobilisation at higher Eh), uranium content of rocks (aqueous concentration increases as rock content increases) and PCO2 (low PCO2 favours higher pH, rapid accumulation of aqueous U and earlier saturation with respect to uranium minerals).

1 September 2016 in IOP Conference Series: Earth and Environmental Science
Verified
Conference Paper
Open access
PDF file
VKV V Kramarenko
V V Kramarenko
ANAleksei Nikitenkov
Aleksei Nikitenkov
IMI A Matveenko
I A Matveenko
VMV Yu Molokov
V Yu Molokov
YVYe S Vasilenko
Ye S Vasilenko
The article deals with the techniques of soil water content determination using microwave radiation. Its practical application would allow solving the problems of resource efficiency in geotechnical survey due to reduction of energy and resource intensity of laboratory analysis as well as its acceleration by means of decreasing labour intensity and, as a result, cost reduction. The article presents a detail analysis of approaches to soil water content determination and soil drying, considers its features and application. The study in soil of different composition, typical for Western Siberia including organic and organic-mineral ones, is a peculiarity of the given article, which makes it rather topical. The article compares and analyzes the results of the investigation into soil water content, which are obtained via conventional techniques and the original one developed by the authors, consisting in microwave drying. The authors also give recommendation on microwave technique application to dry soil.

1 September 2015 in Thin Solid Films
Verified
Journal Article
Closed access
NNNukolay Nikolaevich Nikitenkov
Nukolay Nikolaevich Nikitenkov
OVO.V. Vilkhivskaya
O.V. Vilkhivskaya
ANAleksei Nikitenkov
Aleksei Nikitenkov
YTYu.I. Tyurin
Yu.I. Tyurin
VSV.S. Sypchenko
V.S. Sypchenko
ISI.A. Shulepov
I.A. Shulepov

1 March 2016 in IOP Conference Series: Earth and Environmental Science
Verified
Conference Paper
Open access
PDF file
VKV V Kramarenko
V V Kramarenko
ANAleksei Nikitenkov
Aleksei Nikitenkov
VMV Yu Molokov
V Yu Molokov
ASA V Shramok
A V Shramok
GPG P Pozdeeva
G P Pozdeeva
The problem of rapid drying arises when determining moisture, ash and organic matter content, as well as during many other soil tests. For highly-organic and organo-mineral peat soils the problem of advanced measurement of moisture content is of special importance, since after reweighing the dry sample increase in mass may be observed. The article examines the methods in determining the moisture content in peat and organic soils via microwave radiation, which will greatly speed up the process, simplify the complexity and cost of laboratory tests. The paper presents a detailed review of the methods determining moisture content in soils and characteristics, as well as application scope. The work contains the research results on moisture organic soils: drying in a microwave oven and the current domestic standards.

1 November 2014 in Journal of Surface Investigation: X-Ray, Synchrotron and Neutron Techniques
Verified
Journal Article
Closed access
PDF file
NNNukolay Nikolaevich Nikitenkov
Nukolay Nikolaevich Nikitenkov
EKE. S. Kiselyova
E. S. Kiselyova
MKM. E. Konischev
M. E. Konischev
VSV. S. Sypchenko
V. S. Sypchenko
ANAleksei Nikitenkov
Aleksei Nikitenkov
MEMatthias Epple
Matthias Epple
The structure, morphology and properties of titanium-oxynitride coatings deposited by pulsed reactive magnetron sputtering were investigated. The methods of X-ray diffractometry, Raman spectroscopy, secondary ion mass-spectrometry and scanning electron microscopy are used. It is established that the structure, and the elemental and phase composition of coatings depend on the size of the ratio of oxygen/nitrogen in the composition of the reactive gas, and also on the magnitude of the negative bias applied to the substrate. The increase in the fraction of nitrogen leads to a reduction in the speed of sputtering, to a reduction in the contact angle of wetting, an increase in hardness and a reduction in Young’s modulus when a negative offset was used.

7 June 2019 in E3S Web of Conferences
Verified
Conference Paper
Open access
PDF file
EDEkaterina Matveevna Dutova
Ekaterina Matveevna Dutova
ANAleksei Nikitenkov
Aleksei Nikitenkov
KKKonstantin Kuzevanov
Konstantin Kuzevanov
This article presents experience of development and application of the HydroGeo software package used to handle practical and scientific tasks in the field of hydrogeochemistry and hydrogeology. There are examples of its application and basic scientific and practical results.