Model of pulsating current traction motor taking into consideration magnetic losses in steel

The aim of the work is to develop a mathematical model of the traction motor of the pulsating current of an electric locomotive taking into account the magnetic losses in the motor steel to determine the starting parameters depending on the voltage of the armature winding. Methodology. Mathematical modeling of electromagnetic processes in a traction motor of pulsating current is applied taking into account the nonlinear nature of the armature inductance, the inductance of the excitation winding and the nonlinear nature of the universal magnetic characteristic. The magnetic losses in the steel of the traction motor were taken into account by establishing the dependence of these losses on the frequency of reversal, the magnetic flux in the magnetic circuit of the motor and the geometric dimensions of the motor. Results. The mathematical model of calculation of starting parameters of the traction engine of the pulsating current of the traction drive of the electric locomotive of alternating current taking into account the equation of instantaneous value of losses in engine steel is developed. The dynamic characteristics of the traction motor with pulsating current are obtained. It allows to investigate starting parameters of the traction engine on the basis of the received mathematical model and to design elements of the traction drive of the electric locomotive according to the specification, to choose optimum design parameters. Originality. For the first time a comprehensive study of the pulsating current traction motor was carried out taking into account the nonlinear nature of the armature inductance, excitation winding inductance and nonlinear nature of the universal magnetic characteristic and taking into account the magnetic losses in the motor steel. Practical significance. The model of the traction motor of pulsating current taking into account losses in steel of the engine on the basis of the carried-out calculation is developed. Experimental studies have confirmed the adequacy of the model, which allows to apply the obtained model to develop a mathematical model of an AC electric locomotive to study the electrodynamic processes in it at different modes of operation of the electric locomotive.Запропоновано підхід до імітаційного моделювання тягових електродвигунів пульсуючого струму, заснований на врахуванні нелінійного характеру магнітної характеристики, індуктивностей якоря та обмотки збудження. Розроблено модель магнітних втрат у магнітопроводі якоря електродвигуна та досліджено їх вплив на характер електромагнітних процесів у електродвигуні. Показано, що отримані при цьому рішення узгоджуються з отриманими раніше результатами, але відкриваються додаткові можливості при дослідженні роботи двигуна в складі тягового електроприводу електровозу однофазно-постійного струму

Syria in Regional Security System in 2000-2011

Syria’s role in regional security in the period of 2000-2011 is discussed. Special attention is paid to the coming to power of Bashar Assad, marked by attempts to soften the confrontation of Syria with regional and extra-regional powers, while simultaneously building a flexible system of situational alliances. The relevance of the study is determined by the fact that an independent foreign policy of Syria have angered the US, which during the presidency of George W. Bush sought to establish a doctrine of American leadership in several regions of the world. It is proved that the aggravation of contradictions with the USA and Israel objectively was promoted by the Second Intifada, since Damascus has traditionally supported the Palestinian people’s struggle for national self-determination. Special attention is paid to the fact that Syria made a “turn to the East,” was to improve relations with Iran and Russia. The novelty of the research is seen in the fact that the reasons are shown for the uncompromising attitude of the West towards the fate of the Syrian political regime in the civil war in the country, namely that the government of Bashar Assad has intensified confrontation with the West

Оптимізація вмісту добавок у епокси-поліефірному зв'язувачі для підвищення когезійної міцності композитів

Protective coatings of polymeric composites are proved to be effective in protecting metal surfaces from corrosion and wear. In order to create a polymeric composite material with improved cohesive properties, fillers of different nature and dispersion, modifiers and plasticizers should be introduced into the epoxy-polyester binder. For optimization of the content of components in epoxy-polyester binder, the method of orthogonal central compositional planning was used. Analysing the experimental obtained data, the regression equations for properties such as fracture stresses during the flexion and impact strength were obtained. For the statistical processing of the experimental results, testing of the reproducibility of experiments was performed on the Cochran criterion. Significance of regression coefficients was determined according to Student's criterion. The adequacy of the obtained model was confirmed by Fischer's criterion. According to the results received we have found that the introduction of two-component filler of different nature and dispersion affects the indices of fracture stresses during the flexion of composite material. It is proved that in order to create a composite with increased values of fracture stresses during the flexion, a discrete carbon fiber with particle sizes d = 6…8 μm, l = 0.5…1.5 mm – 0.05 pts. wt. and an oxidized nanodispersed additive with a dispersion d = 5…8 nm – 0.05…0.075 pts. wt. should be introduced per 100 pts. wt. of epoxy-polyester binder. At this content, the parameters of fracture stresses during the flexion increase to σfl = 72.6…75.5 MPa. Additionally, the effect of two-component filler on the impact strength of the developed epoxy-polyester composite was determined. It is analyzed that the introduction of a discrete carbon fiber at the content from 0.10 to 0.15 pts. wt. and an oxidized nano-dispersed additive at the content from 0.05 to 0.075 pts. wt. per 100 pts. wt. of the epoxy-polyester matrix allows to receive the increased indexes of the impact strength of the composite material (W = 9.1…9.4 kJ/m2). The obtained results allow creating a polymeric material with the improved parameters of cohesive properties in the complex.Доведено, що для захисту елементів металевих поверхонь від корозії та зношення ефективним є використання захисних полімерних композитних покриттів. Встановлено, що для створення полімерного композитного матеріалу з поліпшеними когезійними властивостями потрібно вводити в епокси-поліефірний зв'язувач наповнювачі різної природи та дисперсності, модифікатори та пластифікатори. Експериментально встановлено, що введення двокомпонентного наповнювача різної природи та дисперсності впливає на показники руйнівних напружень під час згинання композитного матеріалу. Методом ортогонального центрального композиційного планування експерименту доведено, що для створення композиту з підвищеними показниками руйнівних напружень під час згинання потрібно вводити дискретне вуглецеве волокно з розмірами часток d = 6…8 мкм, l = 0,5…1,5 мм – 0,05 мас. ч. та окиснену нанодисперсну добавку з дисперсністю d = 5…8 нм – 0,05…0,075 мас. ч. на 100 мас. ч. епокси-поліефірного зв'язувача. При цьому показники руйнівних напружень під час згинання підвищуються до σзг = 72,6…75,5 МПа. Додатково встановлено вплив двокомпонентного наповнювача на ударну в'язкість розробленого епокси-поліефірного композиту. Проаналізовано, що введення дискретного вуглецевого волокна за вмісту 0,10…0,15 мас. ч. та окисненої нанодисперсної добавки 0,05…0,075 мас. ч. на 100 мас. ч. епокси-поліефірної матриці дає змогу отримати підвищені показники ударної в'язкості композитного матеріалу (W = 9,1…9,4 кДж/м2). Отримані результати дають змогу створити полімерний матеріал із поліпшеними в комплексі показниками когезійних властивостей

CHARACTERIZATION OF AVIAN INFLUENZA H5N8 VIRUS STRAINS THAT CAUSED THE OUTBREAKS IN THE RUSSIAN FEDERATION IN 2016–2017

Objective of the study is to investigate biological properties of avian influenza virus strains that caused the outbreaks in Russia in 2016–2017.Materials and methods. The study was performed using advanced virological and molecular-biological methods in state-of-the-art equipment.Results and conclusion. In 2016, the outbreaks among wild birds and poultry caused by highly pathogenic avian influenza H5N8 virus have occurred in the territory of the Russian Federation. In May, 2016 an outbreak of H5N8 among wild birds was registered in the territory of the Republic of Tyva. In October-November, 2016 influenza virus H5N8 was isolated in the territory of the Republics of Tatarstan and Kalmykia, Krasnodar and Astrakhan Regions of Russia. In 2017 avian influenza H5N8 has become widespread in European part of Russia and caused multiple outbreaks among wild birds and poultry. Results of the investigations of the isolated strains show that all of them are highly pathogenic and belong to the clade 2.3.4.4. Molecular-genetic and virological analysis has revealed the differences between the viruses isolated in 2016–2017 and the virus of the same clade 2.3.4.4 that was isolated in 2014

Sterowalność pojazdów szynowych

The term steerability is widely used in the motion theory of wheel and track-laying machines, water and air vehicles, spacecraft. Steerability is a property of a transport machine to submit to the managing influence. Steerability of the machine is defined by its reaction to managing influence on the part of managing in the form of changing travelling course or lateral kinematical parameters. For example, in automobiles this influence is shown in the turn of a steering wheel, in planes it is a rum of steering wheel or controller handle and so on. Railway vehicles, as known, have no similar bodies of control. The change of the moving is carried out by a rail track under the influence of horizontal travelling forces. Using the terminology from the control of wheel carriers, the author considers qualitative parameters of steerability of rail vehicles, connecting them with additional influence on vehicles of the railway in the process of control