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Search results for: CFD/CSD CALCULATIONS
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Diagnostics of bolted lap joint using guided wave propagation
PublicationThe paper presents numerical and experimental analyses of elastic waves propagation in a bolted lap joint. In experimental investigations condition assessment of the joint was performed with the use of symmetric waves excited by a piezoactuator. Numerical calculations were conducted in commercial finite element method software Abaqus. The influence of number of bolts and the value of the initial stress on recorded signals was examined....
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Numerical simulation of screw displacement pile interaction with non-cohesive soil
PublicationA trial numerical simulation of screw displacement pile interaction with non-cohesive subsoil during the transfer of compression load. The simulation was carried out in an axisymmetric system. The technological phases of pile installation in the ground were numerically modelled using equivalent processes which provided similar effects to real technical actions. The results of the numerical calculations were verified by comparing...
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Tesla Friction-Type Micro Turbine For Small-Scale Cogeneration
PublicationTesla turbine is rarely used in professional power installations due to its specific work characteristics and relatively low internal efficiency. However, it has some potential to be applied in micro-power plants operating in distributed co-generation systems, also working in an organic Rankine cycle. This paper presents results from numerical calculations of flow in three models of Tesla disk turbines assuming nitrogen as a working...
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A concept of zero-dimensional and three-dimensional thermodynamic modelling of steam storage in a steam cycle
PublicationThis work presents the thermodynamic model of steam storage in a steam cycle. The innovative steam storage is an integral part of the unit and thus responds quickly to changes in load. This enhances the primary control reserve while maintaining high efficiency of energy conversion. With regard to power plants, it improves the operational safety of generation units, as it prevents boiler and turbines overload in the case of steep...
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Equivalent temperature for design of airport pavements using mechanistic-empirical methods
PublicationThe paper presents implementation of equivalent temperature for design of airport asphalt pavements. The calculation methods of equivalent temperature: the Shell method, the French method and method that use the Asphalt Institute fatique criteria were presented. An example of calculations of equivalent temperature for Gdansk Airport was introduced and discussed. It was shown that methods of calculation of equivalent temperature...
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Receiver-side fingerprinting method based on quaternion sandwich product
PublicationIn this paper a new receiver-side fingerprinting method for color images is proposed. The proposed method belongs to the group of Joint Fingerprinting and Decryption (JFD) methods. Each component of the color image is represented as a point in 3D space, which is formed by 3 color channels. Encryption and fingerprinting can be interpreted as rotation, scaling and translation of these points. Calculations are performed using quaternion...
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Analysis of degaussing process of ferromagnetic objects
PublicationResults of the analytical and numerical analysis of the degaussing process phenomena of ferromagnetic objects were presented in this paper. The screening effectiveness of the electromagnetic field of magnetic screens in most cases depends on thickness, conductivity, magnetic permeability of the screen and angular frequency of degaussing currents. The magnetic field inside thin-layer ferromagnetic object was presented in this paper....
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Magnetizabilities of relativistic hydrogenlike atoms in some arbitrary discrete energy eigenstates
PublicationWe present the results of numerical calculations of magnetizability of the relativistic hydrogenlike atoms. Exploiting the analytical formula for $\chi$ we have found the values of the magnetizability for the ground state and for the first and the second set of excited states of the atom. The results for ions with the atomic number $0
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Experimental and numerical analysis of wave propagation in ground anchors
PublicationThe article focuses on wave propagation phenomenon in ground anchors. The main aim of the investigation is the non-destructive diagnostics and the assessment of the state of ground anchors, using the guided wave propagation method. Laboratory models of anchors with different lengths of the anchor body were tested and voltage signals of propagating waves were registered at several locations. For all tested specimens corresponding...
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Internationalization patterns of Polish family high-tech firms
PublicationThe objective of the article is to explore internationalisation patterns of family high-tech firms, especially their internationalisation motives, intensity, speed, and entry modes. The empirical part adopts a quantitative approach. The results of the survey are presented on the sample of 263 high-tech production firms from Poland, including 101 family firms. The survey was conducted in all 16 Polish regions. The calculations from...
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Theory of valence-band and core-level photoemission from plutonium dioxide
PublicationThe correlated-band theory implemented as a combination of the local-density approximation with the dynamical mean-field theory is applied to PuO2. An insulating electronic structure, consistent with the experimental valence-band photoemission spectra, is obtained. The calculations yield a nonmagnetic ground state that is characterized by a noninteger filling of the plutonium 5f shell. The noninteger filling as well as the satellites...
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A study of the photoelectron spectra of α-tetrahydrofurfuryl alcohol over the outer valence energy region (9–25 eV)
PublicationPhotoelectron spectra of α-tetrahydrofurfuryl alcohol (THFA) molecules, the threshold spectrum and spectra for constant photoelectron energies, have been measured over the photon energy range 9–25 eV. Analysis of the photoelectron spectra has allowed overlapping photoionization bands to be separated, tentatively assigned and their vertical photoionization energies to be determined. These energies are compared with existing theoretical...
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Intramolecular transformation of an antifungal antibiotic nystatin A1 into its isomer, iso-nystatin A1 - structural and molecular modeling studies
PublicationNystatin A1, a polyene macrolide antifungal antibiotic, in a slightly basic or acidic solution undergoes an intramolecular transformation, yielding a structural isomer, the translactonization product, iso-nystatin A1 with lactone ring diminished by two carbon atoms. Structural evidence is provided by advanced NMR and Mass Spectrometry (MS) studies. Molecular dynamics simulations and quantum mechanics calculations gave the insight...
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Hertzian Crack Propagation in Ceramic Rolling Elements
PublicationThe properties of ceramics are of most interest to rolling element manufacturers. The influence of ring crack size on rolling contact fatigue failure has been studied using numerical fracture analysis. Such crack are very often found on ceramic bearing balls and decrease fatigue life rapidly. The numerical calculations are based on a three dimensional model for the ring crack propagation. The stress intensity factors along crack...
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Entrepreneurial Business and Economic Review
PublicationThe objective of the article is to explore internationalisation patterns of family high-tech firms, especially their internationalisation motives, intensity, speed, and entry modes. The empirical part adopts a quantitative approach. The results of the survey are presented on the sample of 263 high-tech production firms from Poland, including 101 family firms. The survey was conducted in all 16 Polish regions. The calculations from...
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Numerical Modelling of Shear Localization in Granular Bodies using MPM and Non-local Hypoplasticity
PublicationThe paper deals with modelling of shear localization in granular bodies by means of an enhanced hypoplastic constitutive model and material point method (MPM). The calculations were carried out for plane strain compression of non-cohesive sand. In order to properly capture the width and inclination of shear zones, the constitutive model was enriched by a characteristic length of micro-structure by means of a non-local theory....
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A device for measuring heat flux on a rocket skin surface
PublicationA novel method for measuring heat flux on a surface is presented. It is an extensive upgrade of currently known heat flux sensors used mostly in civil engineering. As the thermal environment of launchers, especially sounding rocket can have an enormous negative effect on payload, careful considerations have to be taken in the process of preparing insulation. Usually, thermal data provided by the launch vehicle manufacturer is limited...
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Density functional theory-based simulations of sum frequency generation spectra involving methyl stretching vibrations: effect of the molecular model on the deduced molecular orientation and comparison with an analytical approach
PublicationThe knowledge of the first hyperpolarizability tensor elements of molecular groups is crucial for a quantitative interpretation of the sum frequency generation (SFG) activity of thin organic films at interfaces. Here, the SFG response of the terminal methyl group of a dodecanethiol (DDT) monolayer has been interpreted on the basis of calculations performed at the density functional theory (DFT) level of approximation. In particular,...
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DETERMINATION OF THE AERODYNAMIC DRAG OF PNEUMATIC LIFE RAFTS AS A FACTOR FOR INCREASING THE RELIABILITY OF RESCUE OPERATIONS
PublicationEnsuring the safety of ship crews at sea is of the utmost importance. Life rafts are one of the basic components of any seagoing vessel and ensuring their stability is an important component of maritime research. This study concerns the determination of the aerodynamic drag coefficients of pneumatic life rafts in a full range of wind speed and directions. The drag coefficients are based on full-scale experimental studies and numerical...
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Superconductivity and appearance of negative magnetocaloric effect in Ba1–xKxBiO3 perovskites, doped by Y, La and Pr
PublicationRecently, substantial attention is given to the bismuth-based perovskites for variety of electronic applications. The perovskites are used for quantum dots displays (QLED), photovoltaic systems and superconducting (HTS) devices. In this paper comprehensive studies of Ba1–xKxBi1–yREyO3 bismuth perovskites (REBKBO, RE = Y , La or Pr) are reported. Apart from structural anomalous behavior at low temperatures, the electronic properties...
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The importance of anchoring ligands of binuclear sensitizers on electron transfer processes and photovoltaic action in dye-sensitized solar cells
PublicationThe relatively low photon-to-current conversion efficiency of dye-sensitized solar cells is their major drawback limiting widespread application. Light harvesting, followed by a series of electron transfer processes, is the critical step in photocurrent generation. An in-depth understanding and fine optimization of those processes are crucial to enhance cell performance. In this work, we synthesize two new bi-ruthenium sensitizers...
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Reactive imines: Addition of 2-aminopyrimidine to the imine bond and isolation of the aminal from the equilibrium mixture aminal/imine
PublicationThe reaction between o-vanillin and 2-aminopyrimidine leads to the formation of a single crystalline product: aminal, 1, which results from the reaction of the initially formed imine with 2-aminopyrimidine. The reaction was followed by the NMR spectroscopy. VT NMR studies prove that in solution two major species are observed: aminal and imine and their ratio depends on the time or/and temperature with the imine content increasing...
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Lead(II) coordination polymers with imidazole-4- and pyrazole-3-carboxylate isomeric linkers: Structural diversity and luminescence properties
PublicationUsing 1H-imidazole-4-carboxylic acid (4imCOOH) and 1H-pyrazole-3-carboxylic acid (3pyrCOOH) coordination polymers [Pb(4imCOO)2(H2O)]n (1) and [Pb2(3pyrCOO)4]n (2) were constructed. Obtained polymers were characterized via FT-IR, X-ray, PL and TG methods. The coordination polyhedron around Pb(II) in 1 is described as distorted pentagonal pyramid with hemidirected coordination sphere (based on DFT calculations). Compound 2 consists...
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The thermal effort during marine steam turbine flooding with water
PublicationThe work discussed an extreme case of cooling a steam turbine. The ship's steam turbine was used as an example. In marine transport units with low-speed engines dominate, however, there are also units with steam turbines. An example of analysed marine steam turbine is shown in Fig. 1. When considering the issue of cooling steam turbines, it is necessary to estimate the extreme conditions that may occur during operation of the turbine....
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Load-settlement characteristics of piles working in a group
PublicationLoad-settlement characteristic (Q-s) of an axially loaded pile can be empirically determined from a static pile load test or on the basis of calculations using, e.g. transfer functions or numerical methods (FEM). The transfer functions method usually rely on empirical data, i.e. the function parameters are determined on the basis of numerous pile test results. Thus this method takes into account pile installation technology and...
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Analysis of Historic Brick Walls' Strengthening Methods
PublicationAnalysis of the behavior of historical brick walls is difficult and complicated. However, computer calculations are being increasingly used in the evaluation of cultural heritage buildings and some of their elements. The aim of this paper is to analyze the historic brick walls reinforcement. Different methods of strengthening are compared and discussed. Numerical analysis, based on finite element method, was conducted on the assumption...
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Image-based numerical modeling of the tensile deformation behavior and mechanical properties of additive manufactured Ti–6Al–4V diamond lattice structures
PublicationThis work concerns the numerical modeling of the deformation process and mechanical properties of structures obtained by the additive method laser power bed fusion (LPBF). The investigation uses diamond structures of Ti–6Al–4V titanium implantation alloy with various relative densities. To model the process of tensile deformation of the materials, geometric models were used, mapping the realistic shape of the examined structures....
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Design Analysis of Micro Gas Turbines in Closed Cycles
PublicationThe problems faced by designers of micro-turbines are connected with a very small volume flow rate of working media which leads to small blades’ height and high rotor speed. In the case of gas turbines this limitation can be overcome by the application of a closed cycle with very low pressure at the compressor inlet (lower than atmospheric pressure). In this way we may apply a micro gas turbine unit of accepted efficiency to work...
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Evolution of Ag nanostructures created from thin films: UV–vis absorption and its theoretical predictions
PublicationAg-based plasmonic nanostructures were manufactured by thermal annealing of thin metallic films. Structure and morphology were studied using scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HR-TEM) and X-ray photoelectron spectroscopy (XPS). SEM images show that the formation of nanostructures is influenced by the initial layer thickness as well as the...
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Arch bridges under test loadings
PublicationThis paper illustrates experience in arch bridges test loadings of the research team of Department of Structural Mechanics and Bridge Structures from the Gdansk University of Technology. The presented calculations results constist the analysis of spatial construction schemes made using the finite elements method (FEM) and its comparison to the field studies. Arch bridges with the longest spans, visualisation of the computational...
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Validation of a sampling procedure
PublicationEach step of the analytical procedure influences the final results in a significant way. In the majority of cases the analytical procedure encompasses sampling because the analysis of the entire object (material) is usually not possible. Thus it is necessary to include the uncertainty related to sampling procedure in the uncertainty budget calculations. This paper describes two basic ways of estimating the sampling uncertainty,...
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Effect of GIS parameters on modelling runoff from river basin. The case study of catchment in the Puck District
PublicationThe study was preceded to check the impact of the adopted digital elevation model resolution on the determination of catchment parameters and the further influence of the received information on calculations related to the hydrograph at the closing point of the basin after a synthetic 100-year precipitation episode. The study area are river basins located in the Puck commune convoying water directly to the Puck Bay. These studies...
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Equivalent temperature for design of asphalt pavements in Poland
PublicationThe paper presents application of equivalent temperature for design of asphalt pavements. The calculation methods of equivalent temperature: the Shell method, the French method, the methods that use the AASHTO and the Asphalt Institute fatigue criteria were presented. The results of calculations of equivalent temperature for Polish climatic conditions were presented and discussed. It was shown that different asphalt pavement design...
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Spatial Modelling in Environmental Analysis and Civil Engineering
PublicationAs can be seen, Spatial Modelling in Environmental Analysis and Civil Engineering applies to a multitude of applications. In an attempt to bring the topic closer to potential readers, the special issue referred to security methods, optimization of calculations, conducting measurements and empirical tests. Each article has made an original contribution to the development of practical science that can be replicated by researchers...
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Drewniane więźby dachowe żuławskich domów podcieniowych typu III – badania, stan zachowania, analiza
PublicationZabytkowe domy podcieniowe ujścia Delty Wisły były obiektem zainteresowań wielu badaczy, jednak ich prace koncentrowały się głównie na aspektach historyczno-architektonicznych. Nie ma publikacji skupiających się na szczegółach i dokładnych analizach ustrojów budowlanych dla tej grupy historycznych obiektów. Artykuł jest rezultatem badań terenowych, kwerendy archiwalnej i obliczeń wykonanych przez autora....
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Simulation of fluid structure interaction in a novel design of high pressure axial piston pump
PublicationA novel type of an axial, piston-driven high pressure hydraulic pump with variable capacity marks a significant improvement in the area of the hydraulic machinery design. Total discharge from hydrostatic forces eliminates a need for a servomechanism, thus simplifying operation, reducing weight and introducing the possibility of the pump displacement control by computer. PWK-type pumps, invented in the Gdansk University of Technology,...
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Applying response surface method to optimize the performance of a divergent-chimney solar power plant
PublicationOne of the effective tools to generate electricity from solar energy is Divergent-chimney solar power plant (DSPP). Divergent and cylindrical chimneys of solar power plants have different performances considering turbine pressure drop ratio (ft). For the first time, the divergent angle (DA) and solar radiation (SR) interaction effects on 〖ft〗_opt are discussed through applying the Computational Fluid Dynamics (CFD) and Response...
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The retrofitting of ships by applying retractable bow hydrofoils: a case study
PublicationIncreasing environmental requirements and a relatively long ship life of 30 years mean more attention is needed to retrofit existing ships. One possibility is using hydrofoils to reduce the ship’s resistance and improve comfort and safety in rough sea conditions. This study investigates the influence of retractable bow hydrofoils on the seakeeping performance and operational conditions of a selected case study vessel (V-shaped...
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Simulation of fluid structure interaction in a novel design of high pressure axial piston hydraulic pump
PublicationA novel type of an axial, piston-driven high pressure hydraulic pump with variable capacity marks a significant improvement in the area of the hydraulic machinery design. Total discharge from hydrostatic forces eliminates a need for a servomechanism, thus simplifying operation, reducing weight and introducing the possibility of the pump displacement control by computer. PWK-type pumps, invented in the Gdansk University of Technology,...
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Chip suction system in circular sawing machine: empirical research and computational fluid dynamics numerical simulations
PublicationThe experimental analysis of the wood chip removing system during its redesigning in the existing sliding table circular saw and computational fluid dynamic (CFD) numerical simulations of the air flow process is presented in the paper. The attention was focused on the extraction hood and the bottom shelter of the actual existing system. The main aim was to perform experimental research on the pressure distribution inside the...
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INNOVATIVE THERMODYNAMICAL CYCLES BASED ON ENHANCEMENT MASS, MOMENTUM, ENTROPY AND ELECTRICITY TRANSPORT DUE TO SLIP, MOBILITY, TRANSPIRATION, ENTROPY AND ELECTRIC JUMPS AS WELL AS OTHER NANO-FLOWS PHENOMENA
PublicationIn our work, a further development of the authors model of thermo-chemical flow of fuel, air, oxygen, steam water, species, ionic and electron currents within nano channels and nano-structures of novel devices is presented. Different transport enhancement models are taken into account -among them the most important are: the velocity slip connected with complex external friction, the Darcy mobility and the Reynolds transpiration....
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Parametric Study on a Performance of a Small Counter-Rotating Wind Turbine
PublicationA small Counter-Rotating Wind Turbine (CRWT) has been proposed and its performancehas been investigated numerically. Results of a parametric study have been presented in this paper.As parameters, the axial distance between rotors and a tip speed ratio of each rotor have been selected.Performance parameters have been compared with reference to a Single Rotor Wind Turbine (SRWT).Simulations were carried out with Computational Fluids...
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Locating and Identifying Ferromagnetic Objects
PublicationThe new non-iterative method of determining the dipole moment and location is presented in this paper. The algorithm of an object's localization and identification was achieved by using numerical calculations and approximation method. The arbitrary shapes of an object were assumed in the identification algorithm - axially symmetric spheroid (a prolate and an oblate). Several examples of localization and identification of an object's...
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Doppler effect in the CW FM sonar
PublicationWhen sonars are used for military purposes they have to ensure unobtrusive operation, a feature that can be potentially secured by 'silent sonar' or continuous wave frequency modulation sonars (CW FM sonars). The article presents how these sonars operate and identifies the relations between their parameters. The Doppler effect and its impact on the CW FM sonar are studied to identify how it affects the sonar's parameters. The results...
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Analysis of the selection of low-temperature medium for a turbine power plant using ocean thermal energy (OTEC)
PublicationThe paper presents the results and conclusions of numerical calculations modelled in the EES program of a closed OTEC cycle. The following mediums were analysed: ammonia, R32, R41, R404a, R407c, R410a, R423a, R500, R502, R507a and R114, R152a, R234fa, R600, R1234yf, R1234ze. Analogous assumptions were adopted as in the ORC cycle with heat regeneration for dry refrigerants without regeneration for wet refrigerants. Each of them...
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Locating and Identifying Ferromagnetic Objects
PublicationThe new non-iterative method of determining the dipole moment and location is presented in this paper. The algorithm of an object's localization and identification was achieved by using numerical calculations and approximation method. The arbitrary shapes of an object were assumed in the identification algorithm - axially symmetric spheroid (a prolate and an oblate). Several examples of localization and identification of an object's...
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Big Data from Sensor Network via Internet of Things to Edge Deep Learning for Smart City
PublicationData from a physical world is sampled by sensor networks, and then streams of Big Data are sent to cloud hosts to support decision making by deep learning software. In a smart city, some tasks may be assigned to smart devices of the Internet of Things for performing edge computing. Besides, a part of workload of calculations can be transferred to the cloud hosts. This paper proposes benchmarks for division tasks between an edge...
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Evaluation of the Impact of Different Types of Uncoupling on the Processing Capacity of Hump Yards
PublicationThe paper considers the issue of evaluating the impact of different types of uncoupling to increase the processing capacity of hump yards to ensure high technical-economic indicators in the conditions of limited capital funds. Moreover it describes the mathematical formulation of the sorting slide. For the mathematical formulation, the sorting slide is taken as a surface that is uniquely projected onto a horizontal plane. Based...
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Electromagnetic Simulations with 3D FEM and Intel Optane Persistent Memory
PublicationAbstract—Intel Optane persistent memory has the potential to induce a change in how high-performance calculations requiring a large system memory capacity are conducted. This article presents what this change may look like in the case of factorization of large sparse matrices describing electromagnetic problems arising in the 3D FEM analysis of passive highfrequency components. In numerical tests, the Intel oneAPI MKL PARDISO was...
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Diagnostics of historic columns using wave propagation
PublicationThis paper presents a numerical analysis of elastic wave propagation in columns of historical buildings for diagnostics purposes. Numerical calculations were performed using the finite element method in the Abaqus software package. The analysis was carried out for three types of brick columns: a full column, a column filled with debris, and a column empty inside. The excitation was in the form of a wave packet and signals of propagating...