Wyniki wyszukiwania - BazTech

1

Chronology of seafloor massive sulfides formation within the Pobeda hydrothermal cluster (Mid-Atlantic Ridge)

Kuznetsov V., Cherkashov G., Kuksa K., Firstova A., Maksimov F., Bel’Tenev V., Lazareva L., Levchenko S., Baranova N.

Geochronometria

|

2020

|

Vol. 47, no.1

63--70

EN

A geochronological and mineralogical study on the seafloor massive sulfides from the Pobeda hydrothermal cluster at the Mid-Atlantic Ridge was carried out. To improve the reliability of geochronological data, the 230Th/U ages were measured for both the bulk samples and monomineral separates. The oldest age ca. 52 kyr within Pobeda-1 and ca. 107 kyr within Pobeda–2 fields have been obtained. Then, several episodes of hydrothermal activity were identified within both fields up to ca. 0.3 kyr ago and up to ca. 4.3 kyr ago, respectively.

2

The efficiency of using artificial feedforward neural networks with a single hidden layer of eight neurons for the analysis of overload conditions of selected tramway traction substations

Dudzik M., Prusak J., Drapik S., Kuznetsov V.

Technical Transactions

|

2018

|

Vol. 115, iss. 11

119--131

EN

This paper presents further results of research on the load variability of rectifier units for the selected tram traction substation. Actual measurements were used in the performed analysis. This time, the analysis was focused on the characteristics of maximum loads and overloads for time periods of five minutes and sixty minutes, for a number of selected cases. The second part of the article discusses the effectiveness of the use of artificial neural networks of the feedforward type with one hidden layer with eight neurons to analyse the overloads of the traction substation over a longer time scale. The obtained positive results indicate that this type of research should be continued, using different variants of artificial neural networks.

PL

W artykule przedstawiono kolejne wyniki badań zmienności obciążeń zespołów prostownikowych wybranej tramwajowej podstacji trakcyjnej. Do analiz wykorzystano rzeczywiste wyniki pomiarów. Tym razem zwrócono uwagę na specyfikę maksymalnych obciążeń i przeciążeń w odcinkach czasowych 5 min i 60 min – dla kilku wybranych przypadków. W drugiej części artykułu przedstawiono efektywność wykorzystania sztucznych sieci neuronowych, typu feedforward o jednej warstwie ukrytej z ośmioma neuronowami, do analizy przeciążeń dla eksploatacji podstacji trakcyjnej w dłuższej skali czasowej. Uzyskane pozytywne wyniki wskazują na konieczność kontynuowania tego typu badań, m.in. wykorzystując inne warianty sztucznych sieci neuronowych.

3

The method for increasing the efficiency of equipment’s maintenance in railway traction power supply systems

Matusevych O., Kuznetsov V., Sychenko V.

Archives of Transport

|

2018

|

Vol. 47, iss. 3

39--47

EN

Purpose. To develop the method for increasing the efficiency of the equipment’s maintenance and repair system, ensuring necessary level of operational reliability of the equipment, safety and reliability of the electric equipment with minimal expenses on operation. Relevance. Aging of the power equipment in railway power supply systems sharply raised a need for assessment of its states and degree of risk for operation outside rated service life. In critical conditions of technological processes and operational modes of the railways it is necessary to increase the equipment’s operational reliability. The scheduled maintenance and repair system whose main technical and economic criterion is the minimum of equipment’s downtimes on the basis of a rigid regulation of repair cycles, in the conditions of market regulations in the field of repair in many cases does not provide the optimal decisions due to insufficient financing. The solution of this problem is possible by improvement of the maintenance and repair system. Under these conditions the main direction for supporting the operational reliability of power electric equipment on TS is a development of the modern methods based on individual supervision over real changes of technical condition of power equipment. Scientific novelty. In this article the authors proposed an integrated approach, on the basis of which can be developed the effective maintenance and repair system for traction power supply systems. Proposed approach allowed to react quickly to changes of service conditions on traction substations, to control the technical condition of power electric equipment under the conditions of uncertainty, to establish interrelation between quality of service and operational reliability of the equipment, to choose a service strategy on traction substations. Practical importance. The validity of the developed method was confirmed by the results of calculations and practically by choosing the optimal maintenance's option for transformer TDTN-25000/150-70 U1 (ТДТН-25000/150-70 У1) on traction power supply substation.

4

Resource-saving technologies of railway transportation of grain freights for export

Kozachenko D., Vernigora R., Kuznetsov V., Lahvinova N., Rustamov R., Papahov A.

Archives of Transport

|

2018

|

Vol. 45, iss. 1

63--74

EN

The research objective is to increase the efficiency of export railway transportation of grain freights in Ukraine by the introduction of consignor routing, a concentration of loading of grain on junction elevators and the organization of the movement of grain routes according to the schedule. According to the researchers in USA and EU, one of the effective directions for decreasing the expenses in a logistic chain of grain delivery to ports is consignor routing of railway transportation. Consignor routing of transportations of grain freights provides a concentration of their loading at junctions. The choice of junctions is proposed to be carried out on the basis of methods of the cluster analysis. For formation of regions for a concentration of grain loading the theory of sets and multicriteria optimization are used. As a result, on the basis of the modified simplex method are chosen 24 regions of possible concentration of grain loading that cover 70 stations on Ukrainian railways providing 7,5 million t consignor routing for grain in a year with minimal additional expenses. The assessment of the efficiency of railway transportation routing of grain freights is calculated with use of the developed simulation model. Researches showed that application of consignor routing allows to reduce a turn-round cycle for grain wagon in a logistic chain of deliveries up to 27%, and application of the schedule for consignor routes allows to reduce a turn-round cycle up to 62%, in comparison with transportation by car loading. Thus, as showed the calculations executed for one of the directions of grain transportation for export, the necessary operation park of grain-carrier wagons is reduced twice, thereby allowing to cut logistic expenses on a delivery of the Ukrainian grain through seaports to the world markets.

5

Recent developments in Qucs-s Equation-Defined modelling of semiconductor devices and IC’s

Brinson M., Kuznetsov V.

International Journal of Microelectronics and Computer Science

|

2017

|

Vol. 8, nr 1

29--35

EN

The Qucs Equation-Defined Device was introduce roughly ten years ago as a versatile behavioural simulation component for modelling the non-linear static and dynamic properties of passive components, semiconductor devices and IC macromodels. Today, this component has become an established element for building experimental device simulation models. It’s inherent interactive properties make it ideal for device and circuit modelling via Qucs schematics. Moreover, Equation-Defined Devices often promote a clearer understanding of the factors involved in the construction of complex compact semiconductor simulation models. This paper is concerned with recent advances in Qucs-S/Ngspice/XSPICE modelling capabilities that improve model construction and simulation run time performance of Equation-Defined Devices using XSPICE model syntheses. To illustrate the new Qucs-S modelling techniques an XSPICE version of the EPFL EKV v2.6 long channel transistor model together with other illustrative examples are described and their performance simulated with Qucs-S and Ngspice.

6

Current conveyor equation-defined macromodels for wideband RF circuit design

Brinson M., Kuznetsov V.

International Journal of Microelectronics and Computer Science

|

2017

|

Vol. 8, nr 2

65--71

EN

A high percentage of analogue integrated circuit designs use voltage domain signal processing techniques. Given the fact that integrated circuit current conveyors are high bandwidth current processing devices, often with superior RF performance compared to comparable voltage domain devices, it is surprising that the number of current mode integrated circuits available, as standard of-the-shelf industrial items, is so small. This paper introduces equation-defined device and Verilog-A synthesis approaches to the macromodelling of current conveyor integrated circuits. To illustrate the proposed modelling techniques the properties of a number of modular behavioural level current conveyor macromodel cells are described and their performance compared. The material presented is intended for analogue device modellers and circuit designers who wish to simulate large signal current domain integrated circuit designs. It also demonstrates how synthesized Verilog-A modules can be derived from equation-defined device and conventional subcircuits to form functional, computationally efficient current conveyor macromodels. To illustrate the application of behavioural current conveyor macromodels the design of a six cell CCII+ instrumentation amplifier is introduced and its performance discussed.

7

Distribution of Excess Regenerative Energy in Electric Transport Systems on the Basis of Fuzzy Logic Application

Sablin O., Kuznetsov V., Shinkarenko V., Ivanov A.

Archives of Transport

|

2017

|

Vol. 42, iss. 2

53--63

EN

Purpose. To develop the fuzzy model of distribution of excess regenerative energy in traction and external power supply systems allowing to exercise effective operation of the power equipment. Relevance. For effective distribution of excess regenerative energy in systems of electric transport, as well as for systems equipped with stationary stores of energy and inverting traction substations with regulators of output voltage it is necessary to solve a number of the problems with high degree of uncertainty demanding taking into account a set of random factors such as the modes of power lines and traction loadings. These factors have to be considered in operation for choosing the rational modes of energy stores, inverters and regulators of voltage on buses of substations to provide the rational conditions for energy regeneration on electric transport. Scientific novelty. The control system of energy storage devices, inverters and traction substation output voltage regulators, designed on the basis of fuzzy logic, can provide the necessary conditions for the regeneration on electric transport on sections with a shortage of traction power consumption and allows to optimize the distribution of excess braking energy of transport vehicles. It is achieved by determining the rational relationship between the components of the excess current of regeneration in real time, which can ensure a minimum of power losses of regenerative energy in traction and external power supply systems. Practical importance. The use of the developed approach is effective under the conditions of incomplete information received by measurement systems and on the basis of additional studies it can allow to minimize rated capacity of stores, inverters and traction substation output voltage regulators that could reduce the costs of modernization of existing sections and electrification of new electric transport systems.

8

Badanie skali zmienności obciążeń wybranej tramwajowej podstacji trakcyjnej na podstawie rzeczywistych wyników pomiarowych dla spójnego okresu czasowego obejmującego szesnaście tygodni

Drapik S., Kuznetsov V., Markowski P., Prusak J., Woszczyna B.

Logistyka

|

2015

|

nr 6

1026--1035, CD

PL

Zmienność obciążeń trakcyjnych powoduje, że projektanci muszą dobierać moc zespołów prostow-nikowych dla podstacji trakcyjnych DC ze znacznym przewymiarowaniem. W artykule, na podstawie wyników pomiarowych eksploatowanej tramwajowej podstacji trakcyjnej, przedstawiono skalę przewy-miarowania mocy zespołów prostownikowych tej podstacji. Stwierdzono występowanie znacznych od-cinków czasowych, w których moce zespołów prostownikowych nie są wykorzystywane. Obliczono współczynniki przeciążeń chwilowych dla różnych odcinków czasowych, następnie przeprowadzono ich analizę statystyczną. Zwrócono uwagę na rozwiązanie techniczne mogące w przyszłości ograniczyć straty energii w podstacjach trakcyjnych DC.

EN

Traction load variation causes that designers need to choose the power rectifier units for DC traction substations with significant overcapacity. In the article, based on the measurement results of the exploited tram traction substation, was presented the scale of power oversizing of rectifier units for that substation. Has been identified significant time intervals in which the powers of the rectifier units are not used. Was also calculated instantaneous overload coefficients for the different time intervals, and then base on the results was carried out the statistical analysis. Attention was drawn for the technical solution that could in future reduce energy loss in the DC traction substations.

9

Qucs equation-defined and Verilog-A higher order behavioral device models for harmonic balance circuit simulation

Brinson M., Kuznetsov V.

International Journal of Microelectronics and Computer Science

|

2015

|

Vol. 6, nr 2

49--58

EN

This paper is concerned with the development and evaluation of a number of modeling techniques which improve Qucs Harmonic Balance simulation performance of RF compact device models. Although Qucs supports conventional SPICE semiconductor device models, whose static current/voltage and dynamic charge characteristics exhibit second and higher order derivatives may not be continuous, there is no guarantee that these will function without Harmonic Balance simulation convergence problems. The same comment also applies to a number of legacy compact semiconductor device models. The modeling of semiconductor devices centered on non-linear Equation-Defined Devices and blocks of Verilog-A code, combined with linear components, is introduced. These form a class of compact macromodel that has improved Harmonic Balance simulation performance. To illustrate the presented modeling techniques RF diode, BJT and MESFET macromodels are described and their Harmonic Balance performance simulated with Qucs and Xyce©.

10

The oldest seafloor massive sulfide deposits at the Mid - Atlantic Ridge: 230th/u chronology and composition

Kuznetsov V., Tabuns E., Kuksa K., Cherkashov G., Maksimov F., Bel’Tenev V., Lazareva L., Zherebtsov I., Grigoriev V., Baranova N.

Geochronometria

|

2015

|

Vol. 42, no.1

100--106

EN

A geochronological and geochemical study on 10 samples of seafloor massive sulfides (SMS) from the inactive Peterburgskoye hydrothermal field at the Mid-Atlantic Ridge (MAR) was carried out. The 230Th/U ages of the SMS are the oldest for the Quaternary hydrothermal ores ever found at the ocean floor. According to them the hydrothermal activity at Peterburgskoye field started at least 170 ka and continued down to 63 ka. The oldest hydrothermal ores from this field consist mainly of pyrite and chalcopyrite and have geochemical properties typical for SMS associated with basalts.

11

Comparative 230Th/U and 14C Dating of a Buried Stump Layer (Western Siberia)

Maksimov F., Kuznetsov V., Laukhin V., Kuksa K., Levchenko S., Grigoriev V.

Geochronometria

|

2015

|

Vol. 42, no.1

139--147

EN

Dating of late Pleistocene sediments remains a challenge in Quaternary chronology, due to the inherent limitations of the 14C and OSL methods. The 230Th/U radioisotope method is theoretically applicable to wood remnants contained within Pleistocene sediments, but few results have been published to date and in some cases, the age data are ambiguous. This paper tests the use of 230Th/U dating of fossil wood remnants dated earlier by radiocarbon method. We analyzed a buried larch trunk from a well-known stump layer in the Lipovka outcrop, located on the Tobol River bank in Western Siberia. The stump layer is preserved in situ. We determined the specific activities of U and Th isotopes in samples of both modern pine and fossil larch and proposed a model for the incorporation and distribution of U and Th in the buried wood during aging. Complications related with the recognition of geochemical closed systems with respect to U did not allow obtaining completely reliable 230Th/U age. Despite this the 230Th/U age obtained for the uppermost heartwood sample and 14C ages of the same larch trunk and other wood and vegetation remnants gave consistent results. These age data in combination with previously obtained pollen data testify the stump layer formation during the late cooling stage of the Karganian time (MIS-3, Middle Valdai).

12

230Th/U chronology of ore formation within the Semyenov hydrothermal district (13°31' n) at the Mid-Atlantic Ridge

Kuznetsov V., Maksimov F., Zheleznov A., Cherkashov G., Bel’tenev V., Lazareva L.

Geochronometria

|

2011

|

Vol. 38, no. 1

72-76

EN

A radiochemical study was carried out on massive sulfides from Semyenov hydrothermal district at the Mid-Atlantic Ridge. New and published results provide evidence that 230Th/U ages obtained for massive sulfides are reliable. The sulfide deposits from the West, North-West, North-East, and East hydrothermal sites at the Semyenov hydrothermal district were formed between ~124 ka and ~37 ka ago. The hydrothermal activity might have started in the eastern part of the district and moved to the west by episodic ore formation.

13

230TH/U dating of massive sulfides from the logatchev and rainbow hydrothermal fields (Mid-Atlantic Ridge)

Kuznetsov V., Cherkashev G., Lein A., Shilov V., Maksimov F., Arslanov K., Stepanova T., Baranova N., Chernov S., Tarasenko D.

Geochronometria

|

2006

|

Vol. 25

51-55

EN

A radiochemical study was carried out on massive sulfides from three hydrothermal fields in the Mid-Atlantic Ridge. The main objective was to check whether 230Th/U dating yields reliable results. The absolute 230Th/U ages of massive sulfide samples of three hydrothermal fields at the Mid Atlantic Ridge were determined 58.2±4.2 ka and 16.8±1.0 ka for the "Logatchev-1" site, 3.9±0.4 ka for the "Logatchev-2" site and 23.0±1.5 ka, 3.9±0.6 ka and 2.2±0.3 ka for the "Rainbow" site. The dates correspond to the activation periods of hydrothermal ore formation systems.

14

Eigenfunctions of rod systems

Stephanov A., Kuznetsov V.

Zeszyty Naukowe. Górnictwo / Politechnika Śląska

|

2000

|

z. 246

503-509

EN

The purpose of this paper is to inform the reader about the applying of distributions in problem of definition of rod system eigenfunctions. The distributions are used for describing system parameters. It is be shown that usage of distributions allow defining analytical solution of eigenfunctions valid for all define area and at the same time diminishing definition complexity of eigenfunctions for different systems.

PL

Celem artykułu jest zaznajomienie czytelnika z zastosowaniem uogólnionych funkcji do rozwiązywania zadań związanych z określeniem funkcji własnych układów prętowych. Funkcje uogólnione wykorzystano do opisania parametrów układu. Zastosowanie funkcji uogólnionych pozwoli na analityczne określenie funkcji własnych ważnych dla całego określonego obszaru, przy czym maleje złożoność określenia funkcji własnych dla różnych układów.

15

Hydrodynamic model of the srim-process and its verification

Polushkin E., Kuznetsov V., Polushkina O., Malkin A. Y., Kleba I., Blaurock J., Michaeli W.

Applied Mechanics and Engineering

|

1999

|

Vol. 4, no spec.

297-302

EN

A two-dimentional hydrodynamic model of a rheokinetic fluid during filling a thin and long mold packed with reinforcement materials are proposed. A core layer of the mold is a porous and rather thick spacer mat. The location of other denser and thinner reinforcement materials into the mold was symmetrical with respect to the spacer mat. During mold filling the fluid easily flows along the core spacer mat and simultaneously impregnates the peripheral reinforcement mats. The model allows to simulate the flow front propagation of the fluid and pressure rise inside the mold during filling. In order to verify the model an original glass mold has been designed and built. The experimental results for the flow front propagation of the fluid were compared with the model predictions and a good coincidence between them has been obtained. For correct comparison of the experimental pressure profiles with the calculated data, the pressure losses in the mold gate must be taken into consideration. These losses can essentially exceed the pressure level into the mold.