Cited Scientists: May 2019

The Cited Scientists project sums up the publication activity of TPU scientists in May 2019. H-index of the most cited co-author of TPU scientists is 40. The IF of the most rated journal where TPU scientists published their articles, is 10.733.

 

Research School of Chemistry & Applied Biomedical Sciences

 

Unprecedented plasmon-induced nitroxide-mediated polymerization (PI-NMP): a method for preparation of functional surfaces

Journal: Journal of Materials Chemistry A (IF 10.733; Q1)

Olga Guselnikova, a research engineer at Research School of Chemistry & Applied Biomedical Sciences (RSCABS), Marina Trusova, RSCABS Deputy Director, Pavel Postnikov, an associate professor at RSCABS, Sylvain R. A. Marque, Gerard Audran (h-index 17), Jean-Patrick Joly from University Aix-Marseille (France); Evgeny Tretyakov (h-index 22), Vorontsov Novosibirsk Institute of Organic Chemistry SB RAS; David Mares, Vitezslav Jerabek, Czech Technical University in Prague; Vaclav Svorcik (h-index 40), Oleksiy Lyutakov (h-index 17), University of Chemistry and Technology in Prague.  

A plasmon as a stimulus opens up new opportunities for selective and regulated “from-surface” polymerization and functionalization of surfaces. Here, the first example of plasmon-assisted nitroxide-mediated polymerization (NMP) of stimuli-responsive block copolymers poly(N-isopropylacrylamide)-co-4-vinylboronic acid is reported. The growth of a polymer film at room temperature was achieved via plasmon-induced homolysis of alkoxyamines covalently attached to the surface of plasmon-active gold gratings at room temperature. Control of temperature, finite-difference time-domain method simulation of plasmon intensity distribution shift during polymerization, electron paramagnetic resonance experiments and other assays provide strong support for the plasmon-initiated mechanism of NMP. We demonstrated not only the control of the resulting polymer thickness but also the preparation of a surface-enhanced Raman spectroscopy chip for the detection of glycoproteins as a powerful example of plasmon-assisted NMP potential. 


Photo: The schematic diagram of the polymerization process.

Quanfima: An open source Python package for automated fiber analysis of biomaterials

Journal: PLoS One (IF 2.766; Q1)

Svetlana Shkarina, a research engineer at the Research Center Physical Material Science and Composite Materials, Roman Surmenev, Director of the Research Center Physical Material Science and Composite Materials, Maria Surmeneva, SRF at the Research Center Physical Material Science and Composite Materials, Roman Shkarin, Andrei Shkarin,  Cecilia Angelica (h-index 23), Venera Weinhardt, Tilo Baumbach (h-index 34), Ralf Mikut (h-index 20) from the Karlsruhe Institute of Technology (Germany).

Hybrid 3D scaffolds composed of different biomaterials with fibrous structure or enriched with different inclusions (i.e., nano- and microparticles) have already demonstrated their positive effect on cell integration and regeneration. The analysis of fibers in hybrid biomaterials, especially in a 3D space is often difficult due to their various diameters (from micro to nanoscale) and compositions. Though biomaterials processing workflows are implemented, there are no software tools for fiber analysis that can be easily integrated into such workflows. Due to the demand for reproducible science with Jupyter notebooks and the broad use of the Python programming language, we have developed the new Python package quanfima offering a complete analysis of hybrid biomaterials, that include the determination of fiber orientation, fiber and/or particle diameter and porosity. Here, we evaluate the provided tensor-based approach on a range of generated datasets under various noise conditions. Also, we show its application to the X-ray tomography datasets of polycaprolactone fibrous scaffolds pure and containing silicate-substituted hydroxyapatite microparticles, hydrogels enriched with bioglass contained strontium and alpha-tricalcium phosphate microparticles for bone tissue engineering and porous cryogel 3D scaffold for pancreatic cell culturing. The results obtained with the help of the developed package demonstrated high accuracy and performance of orientation, fibers and microparticles diameter and porosity analysis. 


Photo: The generated datasets with different fiber configurations: a) aligned (A); b) moderately aligned (M); c) disordered (D);
d) the central slice from the YZ-plane of generated disordered dataset contaminated with additive Gaussian noise and smeared with the Gaussian filter.

 

Optical System With Brightness Amplification for Monitoring the Combustion of Aluminum- Based Nanopowders

Journal:  IEEE Transactions on Instrumentation and Measurement (IF 2.794; Q1)

Lin Li, a PhD student at RSCABS, a technician at the Division of Electronic Engineering of the School of Non-Destructive Testing (SNDT), Andrei Mostovshchikov, SRF at Research Laboratory for Super High Frequency Technology of the School of Nuclear Science & Engineering (SNSE), Alexander Ilyin, a professor at the Division of Natural Sciences at the School of Core Engineering Education (SCEE), Fedor Gubarev, an associate professor at SCABS, Andreas Smirnov from Nuremberg Technical University (Germany).

This paper presents the results of real-time monitoring of air combustion of aluminum nanopowder and its mixtures with aluminum micropowder and iron oxide III. An optical system with a brightness amplifier was used along with visual monitoring to characterize the reflectivity of the sample surface. The reflectivity was analyzed after registering by a photodiode the intensity of radiation reflected from the surface and then amplified by the brightness amplifier at 510.6- and 578.2-nm wavelengths. Analysis of the images obtained with a high-speed camera and the photodiode output oscillograms showed that the intensity of the brightness amplifier output corresponds to the main stages of the combustion process, including the beginning of combustion, spreading of the heat wave and rise of the second combustion wave. The proposed technique is adequate for real-time monitoring of the combustion process with temperatures of 2200 °C-2400 °C, which is accompanied by intensive lighting. 


Photo: A graphical abstract.

 

School of Energy & Power Engineering

Thermal effects investigation during biomass slow pyrolysis in a fixed bed reactor

Journal: Biomass and Bioenergy (IF 3.358; Q1)

Roman Tabakaev, an associate professor, a researcher at the Butakov Research Center, Alexander Astafev, an engineer at the School of Energy & Power Engineering (SEPE), Yulia Shanenkova, an assistant at the Division of Electrical Engineering, Yuri Dubinin, Nikolay Yazykov, Vadim Yakovlev from the  Boreskov Institute of Catalysis SB RAS.

The desire to increase the role of renewable biomass resources in the energy sector sets the task of finding promising areas for its resource-efficient use. Pyrolytic conversion (pyrolysis) of biomass can be considered as one of such directions. The efficiency of pyrolysis depends on the possibility of its implementation in the autothermal mode. In this regard, the purpose of this work is to study the thermal conversion of biomass in the process of slow low-temperature pyrolysis in relation to its implementation in a fixed bed reactor. Physical experiment methods, differential thermal analysis and electron scanning microscopy were used in the work. As a result of the study, it was shown that in the process of straw and peat low-temperature pyrolysis (heating rate of 10?°C/min) a thermal exothermic decomposition effect was observed when the reactor was heated to 500?°C. This effect led to an increase in the rate of heating of the biomass bed. Moreover, in the case of straw pyrolysis, the temperature in the bed began to exceed the temperature of the reactor wall (up to 55–60?°C) when heated above 303?°C. The total values of the exothermic effect of straw and peat pyrolysis in the temperature range of 170–600?°C were 1,475?kJ/kg and 862?kJ/kg, respectively (based on the dry mass of the feedstock). The scanning microscopy method shows the change in the biomass structure during the pyrolytic decomposition process.

 

Research School of High Energy Physics

 

Surface modification of Al by high-intensity low-energy Ti-ion implantation: Microstructure, mechanical and tribological properties

Journal:  Surface and Coatings Technology (IF 2.906; Q1)

Alexander Ryabchikov, the head of the Laboratory of High-Intensity at Ion Implantation Research School of High-Energy Physics (RSHEP), Egor Kashkarov, an assistant at the Division of Experimental Physics, JRF at International Research Laboratory for Hydrogen Energy Technologies, Alexei Shevelev, an engineer at the Laboratory of High-Intensity Ion Implantation, Denis Sivin, SRF at the Laboratory of High-Intensity Ion Implantation, Alexei Obrosov from Brandenburg University of Technology.

A high-intensity metal ribbon ion beam was generated using plasma immersion extraction and the acceleration of the metal ions with their subsequent ballistic focusing using a cylindrical grid electrode under a repetitively pulsed bias. To generate the dense metal plasma flow, two water-cooled vacuum arc evaporators with Ti cathodes were used. The ion current density reached 43?mA/cm2 at the arc discharge current of 130 A. High-intensity ion implantation (HIII) with a low ion energy ribbon beam was used for the surface modification of the aluminium. The irradiation fluence was changed from 1.5?×?1020 ion/cm2 to 4?×?1020 ion/cm2 with a corresponding increase in the implantation temperature from 623 to 823?K. The structure and composition of the Ti-implanted aluminium were studied using X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDX). The mechanical properties and wear resistance were measured using nanoindentation and “pin-on-disk” testing, respectively. It was shown that the HIII method can be used to form a deep intermetallic Al3Ti layer. It has been established that a thin (0.4?μm) modified layer with a hcp Ti(Al) structure is only formed on the surface at 623?K, while the formation of the ordered Al3Ti intermetallic phase occurs at the implantation temperatures of 723 and 823?K. Despite the significant ion sputtering of the surface, the thickness of the modified layer increases from ~1?μm to ~6?μm, and the implantation temperature rises from 723 to 823?K. It was found that the homogeneous intermetallic Al3Ti layer with a thickness of up to 5?μm was formed at 823 К. The mechanical and tribological properties of the aluminium were substantially improved after HIII. For the Ti-implanted aluminium, the hardness of the surface layer increases from 0.4?GPa (undoped Al) to 3.5–4?GPa, while the wear resistance increases by more than an order of magnitude.

 

School of Non-Destructive Testing

 

Kinetic modeling of spatio-temporal evolution of the gain in copper vapor active media

Journal:  Optics Communications (IF 1.887; Q2)

Stanislav Torgaev, an associate professor at the Division of Electronic Engineering, Anton Kulagin, an assistant at the Division of Experimental Physics, a laboratory assistant at the Division of Mathematics and Computer Science, Gennadiy Evtushenko, a professor at the Division of Electronic Engineering, Tatiana Evtushenko from Peter the Great Saint-Petersburg Polytechnic University.

This paper addresses the theoretical study of the spatio-temporal gain profile of the copper vapor active media. The description of a kinetic model of a copper vapor amplifier which allows us to study spatio-temporal evolution of the amplifying characteristics is described. Using the kinetic model time and radial evolution of the medium optical gain and factors which governs the radial gain profile inhomogeneity of the brightness amplifier is shown.

The study was conducted within the grant of the Russian Science Foundation (No. 14-19-00175).