Modeling of a new type of reinforcing insulation of 110 kV cable joints

This article is devoted to the creation of a new reinforcing insulation of high-voltage cable joints at 110 kV. According to statistics for 2016, about 65% of accidents on the cable line occur at the junction of the two cable segments. The problem of leveling the electric field in the cutting is one of the important in the cable industry. To date, it has become possible to create new composite materials with special properties. With this help, a new type of 110 kV amplifying insulation will work on a new combined method of leveling the electric field. Using the finite element method, the model of amplifying insulation (tube-regulator) was modeled. It consists of several components that are responsible for a different principle of leveling the field

Experimental study of negative photoconductivity in n-PbTe(Ga) epitaxial films

We report on low-temperature photoconductivity (PC) in n-PbTe(Ga) epitaxial films prepared by the hot-wall technique on -BaF_2 substrates. Variation of the substrate temperature allowed us to change the resistivity of the films from 10^8 down to 10_{-2} Ohm x cm at 4.2 K. The resistivity reduction is associated with a slight excess of Ga concentration, disturbing the Fermi level pinning within the energy gap of n-PbTe(Ga). PC has been measured under continuous and pulse illumination in the temperature range 4.2-300 K. For films of low resistivity, the photoresponse is composed of negative and positive parts. Recombination processes for both effects are characterized by nonexponential kinetics depending on the illumination pulse duration and intensity. Analysis of the PC transient proves that the negative photoconductivity cannot be explained in terms of nonequilibrium charge carriers spatial separation of due to band modulation. Experimental results are interpreted assuming the mixed valence of Ga in lead telluride and the formation of centers with a negative correlation energy. Specifics of the PC process is determined by the energy levels attributed to donor Ga III, acceptor Ga I, and neutral Ga II states with respect to the crystal surrounding. The energy level corresponding to the metastable state Ga II is supposed to occur above the conduction band bottom, providing fast recombination rates for the negative PC. The superposition of negative and positive PC is considered to be dependent on the ratio of the densities of states corresponding to the donor and acceptor impurity centers.Comment: 7 pages, 4 figure

Recent advances of collagen composite biomaterials for biomedical engineering: antibacterial functionalization and 3D-printed architecturalization

Abstract Collagen possesses high biocompatibility with all tissue and cell types in the body, enabling the creation of multifunctional composite materials for medical applications. In biomedical engineering, naturally-sourced collagen is often combined with diverse organic and inorganic bioactive components to eliminate defects and disorders in fields including orthopedics, dermatology, and more. At the same time, medical-related infection issues and the precise treatment needs of patients require collagen composite biomaterials to have antibacterial properties and customized structures. This paper reviews the antibacterial functionalization of collagen composite biomaterials in recent years, including the combination with inorganic or organic antibacterial agents, which is beneficial for preventing and controlling biological contamination in medical applications. Then, the existing problems and future development directions for the architecturalization of collagen composite materials with 3D printing were discussed, providing guidance for personalized customization of multifunctional materials to meet the specific needs of patients in the future. Graphical Abstrac

ДИАГНОСТИКА ПРОФЕССИОНАЛЬНОГО ЗДОРОВЬЯ ВОЕННОСЛУЖАЩИХ - ПРЕПОДАВАТЕЛЕЙ ОБРАЗОВАТЕЛЬНЫХ ОРГАНИЗАЦИЙ ВМФ - КАК НАПРАВЛЕНИЕ ОБЕСПЕЧЕНИЯ ИХ ПРОФЕССИОНАЛЬНОЙ ДЕЯТЕЛЬНОСТИ

The article deals with perspective directions of protecting the health of teachers of naval universities at the modern stage of construction of the Navy. The features of the activities of the faculty. The research reflects the high importance of ensuring a high reliability of professional activity of military men - teachers of educational institutions of the Navy, by maintaining their occupational health. One of the ways of its solution is a scientific and methodological substantiation and development of a system of measures for diagnosis, preservation and strengthening of professional health of the military personnel, teachers of educational institutions of the Navy. The article presents the rationale for the selection of the external criterion and the methodology of the expert assessment of the success of the military-professional activities of teachers of naval universities. The results of the development of diagnostic regression models characterizing the level of professional health and to predict the number of days of trumpeter in the polar regression equation groups of soldiers - teachers of naval universities. The inclusion of the methodical diagnostic model of psychophysiological characteristics, reflecting and fully describing the methodological principles of the system, reliably and effectively predict how the profession affects the health.Рассматриваются перспективные направления сохранения здоровья преподавателей военно-морских вузов на современном этапе строительства Военно-морского флота. Показаны особенности деятельности преподавательского состава. Исследование отражает высокую актуальность проблемы обеспечения высокой надежности профессиональной деятельности военнослужащих - преподавателей образовательных организаций ВМФ, путем сохранения их профессионального здоровья. Одним из способов ее решения является научно-методическое обоснование и разработка системы мероприятий по диагностике, сохранению и укреплению профессионального здоровья военнослужащих - преподавателей образовательных организаций ВМФ. В статье представлено обоснование выбора внешнего критерия и методики экспертной оценки успешности военно-профессиональной деятельности преподавателей военно-морских вузов. Приведены результаты разработки регрессионной диагностической модели, характеризующей уровень профессионального здоровья и позволяющей прогнозировать количество дней трудопотерь в полярных по регрессионному уравнению группах военнослужащих - преподавателей военно-морских вузов. Включение в методическую диагностическую модель психофизиологических характеристик, отражающих и полно описывающих методологический принцип системности, позволяет достоверно и эффективно прогнозировать, как профессия отражается на здоровье

Effect of Bacterial Cellulose Plasma Treatment on the Biological Activity of Ag Nanoparticles Deposited Using Magnetron Deposition

New functional medical materials with antibacterial activity based on biocompatible bacterial cellulose (BC) and Ag nanoparticles (Ag NPs) were obtained. Bacterial cellulose films were prepared by stationary liquid-phase cultivation of the Gluconacetobacter hansenii strain GH-1/2008 in Hestrin–Schramm medium with glucose as a carbon source. To functionalize the surface and immobilize Ag NPs deposited by magnetron sputtering, BC films were treated with low-pressure oxygen–nitrogen plasma. The composition and structure of the nanomaterials were studied using transmission (TEM) and scanning (SEM) electron microscopy and X-ray photoelectron spectroscopy (XPS). Using electron microscopy, it was shown that on the surface of the fibrils that make up the network of bacterial cellulose, Ag particles are stabilized in the form of aggregates 5–35 nm in size. The XPS C 1s spectra show that after the deposition of Ag NPs, the relative intensities of the C-OH and O-C-O bonds are significantly reduced. This may indicate the destruction of BC oxypyran rings and the oxidation of alcohol groups. In the Ag 3d5/2 spectrum, two states at 368.4 and 369.7 eV with relative intensities of 0.86 and 0.14 are distinguished, which are assigned to Ag0 state and Ag acetate, respectively. Nanocomposites based on plasma-treated BC and Ag nanoparticles deposited by magnetron sputtering (BCP-Ag) exhibited antimicrobial activity against Aspergillus niger, S. aureus and Bacillus subtilis