Cited Scientists: February 2019

The Cited Scientists project sums up the publication activity of TPU scientists in February 2019. H-index of the most cited co-author of TPU scientists is 55. The IF of the most rated journal where TPU scientists published their articles, is 4.908. 


Photo: Ekaterina Chudinova, a research participant.

School of Nuclear Science & Engineering

Compact Active S-Band Microwave Compressors for Producing Rectangular Pulses of Up To 100 ns

Journal: IEEE Transactions on Microwave Theory and Techniques, (IF 3.176, Q1)

Sergey Artemenko, Leading Research Fellow, Research Laboratory for Super High-Frequency Technology, Vladislav Igumnov, Research Fellow, Research Laboratory for Super High-Frequency Technology, Anatoly Shlapakovsky (H-index – 8), Technion – Israel Institute of Technology, Yuri Yushkov, Chief Expert, Research Laboratory for Super High-Frequency Technology.

This paper proposes and describes in detail a new approach to the design of very compact active microwave compressors capable of providing rectangular pulses of up to 100 ns. The approach consists in using a storage cavity, which comprises linear waveguide sections connected by tees such that the cavity geometry can be 2-D or 3-D or can be variable to allow direct space-saving integration of a compressor into a microwave source. Also presented are the scattering matrix data on uniform wave propagation along the storage cavity with little reflection and on conditions necessary for such uniformity. The S-band experiments demonstrate the capability of storage cavities with two and three parallel waveguide sections of about 1 m long to produce rectangular pulses of duration 5, 15, and 25 ns with a power gain and output power of about 16 dB, 80 MW; 15 dB, 60 MW; and 13 dB, 40 MW, respectively. Our estimates suggest that 12 waveguide sections can provide a rectangular pulse of 100 ns with a power gain 10 dB.

 

School of Energy & Power Engineering

Thermal enrichment of different types of biomass by low-temperature pyrolysis

Journal: Fuel (IF 4.908, Q1)

Roman Tabakaev, Research Fellow, the Butakov Research Center, Kanipa Ibraeva, PhD student, the Butakov Research Center, Alexander Astafev, PhD student, the Butakov Research Center, Prof. Alexander Zavorin, Head of the Butakov Research Center, Yuri Dubinin, Nikolay Yazykov, Boreskov Institute of Catalysis SB RAS, Vadim Yakovlev (H-index – 15), Boreskov Institute of Catalysis SB RAS.

An increase of renewable biomass resources in the world fuel and energy balance contributes to reducing the harmful impact of energetics on the environment. Low efficiency of biomass (in its natural form) processing for the energetics purposes by traditional combustion methods leads to the necessity of its preliminary conversion into energy-valuable products. The purpose of this work is an experimental study of low-temperature processing of biomass with varying composition. Physical experiment and differential-thermal analysis were used as the main methods of research. Based on the systematization of the obtained data and other investigations, the dependences of low-temperature pyrolysis products yield for solid organic raw materials on the hydrogen to carbon atomic ratio have been established. With increasing of H/C ratio, the yield of the carbonaceous residue decreases whereas the yield of liquid products and gas increases. It has been established that biomass pyrolysis proceeds with the predominance of exothermic reactions providing a positive heat effect that varies from +262 to +1809?kJ/kg. At the same time, an increase of the H/C ratio in the raw materials results in an increase of the exothermic effect of pyrolysis.

School of Earth Sciences & Engineering

Identification of geochemical anomalies of the porphyry–Cu deposits using concentration gradient modelling: A case study, Jebal-Barez area, Iran

Journal: Journal of Geochemical Exploration, (IF 2.858, Q2)

Timofey Timkin, Associate Professor, Division for Geology, Valery Voroshilov, Professor, Division for Geology, Tamara Yakich, Associate Professor, Division for Geology, Ziaii Mansour, Shahrood University of Technology, Safari Samaneh, Shahrood University of Technology.

This paper presents a novel gradient model for exploration of blind mineralization. The concentration gradient coefficient techniques have been proved to be very well-suited for typical mining geochemistry applications. Gradient concentration corresponds to concentration variations. Large concentration changes due to geochemical data distribution correspond to surfacing anomaly, and less concentration variations are more likely to be related to the deeper geochemical anomalies. The introduced technique is capable to distinguish the difference between the blind mineralization and zone dispersed mineralization, computationally and without exploration drilling. In this research, deep geochemical anomalies are investigated using the gradient concentration values for the porphyry–Cu deposits of the Jebal-Barez region in Iran. Based on the results obtained from the proposed gradient model, values >1.0 in G(Vz) reveal the existence of blind mineralization in the study zone. The findings based on this method suggest that SW of Jebal-Barez is a highly favourable zone for exploration of blind mineralization. The value for G(Vz) in this zone is equal to 5.04. The results obtained in this research were consistent well with the findings of the previous research in the area and the detected Kerver as the main blind mineralization in Jebal-Barez. A local exploration was carried out in this zone in four areas of Kerver using the gradient model.

 

Research School of Chemistry & Applied Biomedical Sciences

Decreased bacterial colonization of additively manufactured Ti6Al4V metallic scaffolds with immobilized silver and calcium phosphate nanoparticles

Journal: Applied Surface Science (IF 4.439, Q1)

Maria Surmeneva, Senior Research Fellow, Research Center for Physical Materials Science and Composite Materials, Leading Engineer at New Pharmaceutical Forms Laboratory, Roman Surmenev, Director, Leading Research Fellow, Research Center for Physical Materials Science and Composite Materials, Ekaterina Chudinova, Research Engineer, Research Center for Physical Materials Science and Composite Materials, Anna Ivanova, Junior Research Fellow, Laboratory of High-Intensity Ion Implantation, Andrey Koptyug, (H-index –  13), Mid Sweden University, Katerina Loza (H-index – 10), Oleg Primak (H-index – 19), Matthias Epple (H-index – 55), Franka Ennen-RothMathias Ulbricht (H-index – 53), University of Duisburg-Essen (Germany), Tomaz Rijavec, Jozef Stefan Institute (Slovenia).

The design of an ideal bone graft substitute has been a long-standing effort, and a number of strategies have been developed to improve bone regeneration. Electron beam melting (EBM) is an additive manufacturing method allowing for the production of porous implants with highly defined external dimensions and internal architectures. The increasing surface area of the implant may also increase the abilities of pathogenic microorganisms to adhere to the surfaces and form a biofilm, which may result in serious complications. The aim of this study was to explore the modifications of Ti6Al4V alloy scaffolds to reduce the abilities of bacteria to attach to the EBM-manufactured implant surface. The layers composed of silver (Ag), calcium phosphate (CaP) nanoparticles (NPs) and combinations of both were formed on the EBM-fabricated metallic scaffolds by electrophoretic deposition in order to provide them with antimicrobial properties. The assay of bacterial colonization on the surface was performed with the exposure of scaffold surfaces to Staphylococcus aureus cells for up to 17?h. Principal component analysis (PCA) was used to assess the relationships between different surface features of the studied samples and bacterial adhesion. The results indicate that by modifying the implant surface with appropriate nanostructures that change the hydrophobicity and the surface roughness at the nano scale, physical cues are provided that disrupt bacterial adhesion. Our results clearly show that AgNPs at a concentration of approximately 0.02?mg/сm2 that were deposited together with CaPNPs covered by positively charge polyethylenimine (PEI) on the surface of EBM-sintered Ti6Al4V scaffolds hindered bacterial growth, as the total number of attached cells (NAC) of S. aureus remained at the same level during the 17 h of exposure, which indicates bacteriostatic activity.