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

Design and characterization of a cobalt-free stainless maraging steel for laser-based powder bed fusion

This study presents a new Co-free stainless maraging variant for laser-based powder bed fusion developed using a computational alloy design approach. The goal was to develop an easily printable material with similar performance to 18Ni-300. After screening numerous compositions, Fe-13.2Cr-9.1Ni-1.1Al-0.6Mo-0.5Nb-0.23Ti-0.5Mn-0.5Si (wt.%) was selected. This composition showed excellent printability with low porosity levels. The precipitation strengthening response was evaluated by aging at 500 \ub0C for 15 min, 3 h and 18 h, measuring hardness, tensile strength, and by characterization using atom probe tomography. After 15 min of aging, 90% of the maximum hardness was reached, thanks to formation of (Ni, Al, Nb, Ti, Mn, Si) clusters with a density of 1.5 7 1024 m-3. Between 15 min and 3 h, distinct precipitates formed with a radius of ∼1.4 nm. The precipitates underwent a splitting phenomenon after 18 h, forming several unique Ni-rich precipitates including Ni16Si7(Ti, Nb)6 and Ni3(Al, Ti, Nb, Si). The splitting can be a reason for the slow coarsening rate, as the average precipitate radius after 18 h was only 2 nm. Simulations of the precipitation sequence using PRISMA indicated very rapid and dense precipitation of L12-Ni3X precipitates with a slow coarsening rate, in agreement with experimental observations

“Ridding the People of England of Tyranny”: Anglo-French Relations in the First Half of the XVI Century

In this article considers the Anglo-French relations of the first half of the XVI century. Special emphasis is placed on the study of two French projects of 1523 and 1544, directed against England. As a result, an attempt is made to understand the strategies and practices characteristic of international relations in the early sixteenth century.В статье исследуются англо-французские отношения первой половины XVI в. Особый акцент делается на изучении двух французских проектов 1523 и 1544 гг., направленных против Англии. В результате предпринимается попытка понять стратегии и практики, характерные для международных отношений начала XVI в

Statistical analysis of high-speed jet flows

The spatiotemporal dynamics of pressure fluctuations of a turbulent jet flow is examined from the viewpoints of symbolic permutations theory and Kolmogorov-Smirnov statistics. The methods are applied to unveil hidden structures in the near-field of the two jets corresponding to the NASA SHJAR SP3 and SP7 experiments. Large Eddy Simulations (LES) are performed using the high-resolution Compact Accurately Boundary-Adjusting high-REsolution Technique (CABARET) accelerated on Graphics Processing Units (GPUs). It is demonstrated that the decomposition of the LES pressure solutions into symbolic patterns of simpler temporal structure reveals the existence of some orderly structures in the jet flows. To separate the non-linear dynamics of the revealed structures from the linear part, the results based on the pressure signals obtained from LES are compared with the surrogate dataset constructed from the original data

Generating Secure Service Compositions

Ensuring that the compositions of services that constitute service-based systems satisfy given security properties is a key prerequisite for the adoption of the service oriented computing paradigm. In this paper, we address this issue using a novel approach that guarantees service composition security by virtue of the generation of compositions. Our approach generates service compositions that are guaranteed to satisfy security properties based on secure service orchestration (SESO) patterns. These patterns express primitive (e.g., sequential, parallel) service orchestrations, which are proven to have certain global security properties if the individual services participating in them have themselves other security properties. The paper shows how SESO patterns can be constructed and gives examples of proofs for such patterns. It also presents the process of using SESO patterns to generate secure service compositions and presents the results of an initial experimental evaluation of the approach

Application of Genetic Programming and Artificial Neural Network Approaches for Reconstruction of Turbulent Jet Flow Fields

Two Machine Learning (ML) methods are considered for reconstruction of turbulet signals corresponding to the Large Eddy Simulation database obtained by application of the high-resolution CABARET method accelerated on GPU cards for flow solutions of NASA Small Hot Jet Acoustic Rig (SHJAR) jets. The first method is the Feedforward Neural Networks technique, which was successfully implemented for a turbulent flow over a plunging aerofoil in (Lui and Wolf, 2019). The second method is based on the application of Genetic Programming, which is well-known in optimisation research, but has not been applied for turbulent flow reconstruction before. The reconstruction of local flow velocity and pressure signals as well as timedependent principle coefficients of the Spectral Proper Orthogonal Decomposition of turbulent pressure fluctuations are considered. Stability and dependency of the ML algorithms on the smoothness property and the sampling rate of the underlying turbulent flow signals are discussed

Rosemary essential oils as a promising source of bioactive compounds: Chemical composition, thermal properties, biological activity, and gastronomical perspectives

Rosemary (Rosmarinus officinalis L.) is a plant worldwide cultivated mainly for essential oils, extracts, and as a spice. Up-to-date results showed diversity in composition of the essential oils, which may influence their quality, biological activity, and thermal properties. Therefore, the aim of this study was to investigate the chemical composition, antimicrobial activity, and thermal properties of the rosemary essential oils originating from Serbia and Russia. Additionally, oils were added to the sunflower oils in order to investigate possible antioxidant activity during the frying. Investigation of the chemical profile marked α-pinene, eucalyptol, and camphor as the most abundant compounds in both oils. However, overall composition influenced in such manner that Russian oil showed significantly higher antimicrobial activity, while Serbian oil proved to be better antioxidant agent in case of frying of sunflower oil. This would significantly influence possible application of the oils, which could be used as an antioxidant agent for extension of the food shelf life, or antimicrobial agent for protection against different microbial strains

e+e- Pairs: a clock and a thermometer of heavy ion collisions

Recently, there is growing evidence that a new state of matter is formed in sqrt(s_NN)= 200 GeV Au+Au collisions at RHIC: a strongly coupled Quark Gluon Plasma of partonic degrees of freedom which develops a collective motion. Dilepton spectra are not affected by strong interaction and can therefore probe the whole time evolution of the collision. Thus they may be sensitive to onset of deconfinement, chiral symmetry restoration, as well as the production of thermal photons. The PHENIX experiment measured the production of e+e- pairs in p+p and Au+Au collisions at sqrt(s_NN)= 200 GeV. An enhanced dilepton yield in the mass range 150<m_ee<750 MeV/c^2 is measured. The excess increases faster with centrality than the number of participating nucleons and is concentrated at p_T<1GeV/c. At higher p_T the excess below 300 MeV/c^2 has been related to an enhanced production of direct photons possibly of thermal origin.Comment: Proceedings of Quark Matter 2008, 8 pages, 7 figure

Тяговый электропривод на основе батареи топливных элементов и бортового инерционного накопителя энергии для мотор-вагонного поезда

The aim of the work is to study the possibility and features of the use of inertial storage devices in the traction electric drive of multi unit train with a power plant based on fuel cells. Methodology. The principle of power flow control in traction electric drives in the modes of acceleration and braking of rolling stock is proposed. The mathematical model of the traction electric drive in the form of the combination of three components: the train, the traction unit and the battery of fuel cells is developed. It was used to study the operation of a traction electric drive when solving a test traction task for rolling stock. Results. It is established that the use of inertial energy storage reduces hydrogen consumption by at least 25 %, which increases the mileage of rolling stock between equipment by more than 30 %. Originality. The traction electric drive on the basis of fuel elements and the inertial energy storage for the multi unit train is offered. The work of the proposed traction electric drive in solving the test traction problem for rolling stock is investigated. Practical significance. A mathematical model of the traction electric drive has been developed. The test traction problem for rolling stock is solved.В роботі розглянуто тяговий електропривод на основі паливних елементів та інерційного накопичувача енергії для мотор-вагонного рухомого складу. Запропоновано принцип керування потоками потужності у тяговому електроприводі у режимах розгону та гальмування рухомого складу. Розроблено математичну модель тягового електропривода у вигляді сукупності трьох складових: поїзда, тягового блока і батареї паливних елементів. За допомогою неї досліджено роботу запропонованого тягового електроприводу при вирішенні тестової тягової задачі для рухомого складу. Встановлено, що застосування інерційного накопичувача енергії зменшує витрати водню не менш ніж на 25 %, що забезпечує збільшення пробігу рухомого складу між екіпіруванням понад 30 %