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Suppression of Supply Current Harmonics of 18-Pulse Diode Rectifier by Series Active Power Filter with LC Coupling
PublicationThe reported research aims at improving the quality of three-phase rectifier supply currents. An effective method consists of adding properly formed booster voltages to the fundamental supply voltages using a series active filter. In the proposed solution, the booster voltages are generated by three single-phase systems consisting of inverters, LC filters, and single-phase transformers. The application of LC couplings ensures low...
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Multivariate Statistical Approach for Nephrines in Womenwith Obesity
PublicationCatecholamines are physiological regulators of carbohydrate and lipid metabolism during stress, but their chronic influence on metabolic changes in obese patients is still not clarified. The present study aimed to establish the associations between the catecholamine metabolites and metabolic syndrome (MS) components in obese women as well as to reveal the possible hidden subgroups of patients through hierarchical cluster analysis...
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Reliable data-driven modeling of high-frequency structures by means of nested kriging with enhanced design of experiments
PublicationData-driven (or approximation) surrogate models have been gaining popularity in many areas of engineering and science, including high-frequency electronics. They are attractive as a way of alleviating the difficulties pertinent to high computational cost of evaluating full-wave electromagnetic (EM) simulation models of microwave, antenna, and integrated photonic components and devices. Carrying out design tasks that involve massive...
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Psychological capital and happiness at work: The mediating role of employee thriving in multinational corporations
PublicationWorking in multicultural work environments of multinational corporations (MNCs) creates challenges whose expected impact on happiness is equivocal. In the following paper, we examine the relationship between psychological capital and happiness at work in the specific MNCs’ context. We assume that thriving (eudemonic well-being) at work fosters individuals’ development and enhances their happiness composed of both the affective...
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Low Cost Hexacopter Autonomous Platform for Testing and Developing Photogrammetry Technologies and Intelligent Navigation Systems
PublicationLow-cost solutions for autonomous aerial platforms are being intensively developed and used within geodetic community. Unmanned aerial vehicles are becoming very popular and widely used for photogrammetry and remote sensing applications. Today’s market offers an affordable price components for unmanned solution with significant quality and accuracy growth. Every year market offers a new solutions for autonomous platforms with better...
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Time-Gating method with automatic calibration for accurate measurements of electrically small antenna radiation patterns in Non-Anechoic environments
PublicationNon-anechoic sites represent a cheap alternative to measurements of antennas in dedicated facilities. However, due to a high noise—from the external EM signal sources and multipath interferences—the quality of radiation patterns obtained in non-anechoic conditions is poor. The characteristics can be corrected using a time-gating method (TGM), which involves filtering of the noise based on temporal analysis of the measured signals....
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Recuperator with microjet technology as a proposal for heat recovery from low-temperature sources
PublicationA tendency to increase the importance of so called dispersed generation, based on the local energy sources and the working systems utilizing both the fossil fuels and the renewable energy resources is observed nowadays. Generation of electricity on industrial or domestic scale together with production of heat can be obtained for example through employment of the ORC systems. It is mentioned in the EU directive 2012/27/EU for cogenerative...
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Constrained optimization for generating gain-bandwidth design trade-offs of wideband unidirectional antennas
PublicationBroadband unidirectional antennas realised in microstrip technology find applications in many wireless communication systems. One of their design challenges is the necessity of handling multiple performance figures which is difficult when using traditional design methods, largely based on parameter sweeping. This work presents a simple optimisation-based framework that permits generation of gain-bandwidth trade-off designs for...
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Fabrication of anti-corrosion nitrogen doped graphene oxide coatings by electrophoretic deposition
PublicationThis work assesses anti-corrosion properties of graphene and N-doped graphene coatings deposited on copper by an electrophoretic method. Graphene oxide (GO) precursor was synthesized by an improved Hummers' method, whereas N-doping was performed hydrothermally in the presence of ammonia. After nitrogenation, doped graphene oxide samples (NGO) contained a reduced amount of oxygen and about 9% w/w nitrogen as pyridinic, pyrrole,...
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Analiza wpływu transmisji danych na jakość działania rozproszonych systemów sterowania
PublicationW artykule przedstawiono zagadnienia związane z transmisją danych w rozproszonych systemach sterowania. Opisano cechy charakterystyczne przemysłowych sieci i protokołów informatycznych. Utworzono model rozproszonego systemu sterowania poziomem cieczy w zbiorniku, w którym komunikacja oparta została na protokole Modbus RTU. Na podstawie zmian parametrów transmisji danych wykazano, że poprawna komunikacja pomiędzy elementami systemu...
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Modelowanie współpracy odbieraka prądu z siecią trakcyjną
PublicationW artykule przedstawiono aspekty oceny współpracy odbieraka prądu z górną siecią trakcyjną na podstawie porównania modeli matematycznych. Zaprezentowano modele odbieraków prądu i sieci jezdnej wskazując na ich użyteczność do oceny siły stykowej i uniesienia przewodów jezdnych. Wykonano szereg symulacji stanów dynamicznych interakcji górnej sieci trakcyjnej i odbieraka prądu dla różnych parametrów. W szczególności zwrócono uwagę...
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Wytrzymałość pętli wplatanych na linach podwójnie plecionych
PublicationCechą wyróżniającą statki żaglowe z grona innych obiektów pływających są żagle. To cecha widoczna, za którą kryją się mniej romantyczne elementy, takie jak maszty, liny i osprzęt. Rozpostarcie białych płócien na maszcie i następnie żeglowanie wymaga sprawnego operowania nimi, co wiąże się z doborem odpowiedniego ich zestawu, ułożenia i napięcia. To maszty są kręgosłupem takielunku, a liny jego mięśniami i ścięgnami. Do poprawnego...
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Concentrations and loads of DOC, phenols and aldehydes in a proglacial arctic river in relation to hydro-meteorological conditions. A case study from the southern margin of the Bellsund Fjord – SW Spitsbergen
PublicationClimate warming accelerates the melting and thawing of cryosphere components. Therefore, it favours the release of contaminants stored in High-Arctic glaciers for many years. The rate of land-based glacier retreat is of particular importance for the hydrological regime of glacial rivers, but also for the chemical composition of their waters. In this study, we examined 84 surface water samples collected during a period of 42 days...
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Development and performance analysis of a novel multiphase doubly-fed induction generator
PublicationThis paper presents the research into the design and performance analysis of a novel five-phase doubly-fed induction generator (DFIG). The designed DFIG is developed based on standard induction motor components and equipped with a five-phase rotor winding supplied from the five-phase inverter. This approach allows the machine to be both efficient and reliable due to the ability of the five-phase rotor winding to operate during...
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Assessment of fitness for service of Cr-Mo steel tubes in catalytic reforming charge heaters
PublicationIn this paper characteristic features of metal dusting corrosion in high temperature gas mixtures of high carbon activity in catalytic reforming units, including Continuous Catalyst Regeneration (CCR) platformer are presented. Examples of 2.25Cr-1Mo and 9Cr-1Mo steel tubes at advanced stages of metal dusting process after long-term service in charge heaters are used to prove that destructive examinations are necessary to provide...
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ASIC Design Example of Complex SoC with FPGA Prototyping
PublicationThe paper presents an example of the System on a Chip design, where the FPGA prototyping has been used. Two FPGA prototypes have been realized. The first FPGA prototype uses AVNET board containing Xilinx Virtex4 device accompanied by custom board with required devices. The second FPGA prototype has been built using the custom PCB with Xilinx Virtex-4 XC4VLX60 FPGA accompanied by all needed external components. The final system...
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Evaluation of Sound Enhancement in Mobile Device Using Virtual Bass Synthesiss Algorithm
PublicationAn experiment conducted to validate possibility of use virtual bass synthesis (VBS) algorithm in a portable computer is presented. The subjective listening tests based on the procedure of pairwise comparison between VBS, based on the so-called missing fundamental phenomenon, and standard bass boost technique are employed. The evaluation was carried out in two types of conditions: in a professional listening room and employing an...
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ASIC Design Example of Complex SoC with FPGA Prototyping
PublicationThe paper presents an example of the System on a Chip design, where the FPGA prototyping has been used. Two FPGA prototypes have been realized. The first FPGA prototype uses AVNET board containing Xilinx Virtex4 device accompanied by custom board with required devices. The second FPGA prototype has been built using the custom PCB with Xilinx Virtex-4 XC4VLX60 FPGA accompanied by all needed external components. The final system...
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Development of the sound field 3D intensity probe based on miniature microphones
PublicationThe engineered measuring probe uses three pairs of miniature microphones coupled. The signals from the microphones after an initial amplification are fed to differential circuits. Due to the required symmetry of the circuit it was necessary to select electronic components very carefully. Moreover, additional digital signal processing techniques were applied to avoid amplitude and phase mismatch. The view of the engineered probe...
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SELECTION OF DIAGNOSTIC FUNCTIONS IN A WHEELED TRACTOR
PublicationIn a classical approach to damage diagnosis, the technical condition of an analyzed machine is identified based on the measured symptoms, such as performance, thermal state or vibration parameters. In wheeled tractor the fundamental importance has monitoring and diagnostics during exploitation concerning technical inspection and fault element localizations. The main functions of a diagnostic system are: monitoring tractor components...
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Action-reaction based synthesis of acoustic wavefield equations
PublicationThe analysis of acoustic fields is usually based on the well-known mathematics of second order partial differential equations called wave equations. The author explores the duality and symmetry of linear fluid mechanics and develops two distinct equations of acoustics on the basis of a causal approach to local small-scale phenomena. Wavefields that are solutions of these equations have different composition, the spherical pressure...
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Sparse vector autoregressive modeling of audio signals and its application to the elimination of impulsive disturbances
PublicationArchive audio files are often corrupted by impulsive disturbances, such as clicks, pops and record scratches. This paper presents a new method for elimination of impulsive disturbances from stereo audio signals. The proposed approach is based on a sparse vector autoregressive signal model, made up of two components: one taking care of short-term signal correlations, and the other one taking care of long-term correlations. The method...
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Observation on red blood cells fluctuations by diffraction phase microscopy
PublicationNowadays there is quite huge need for more and more precise and effective fast diagnostics methods in hematology diseases. One of the most important blood components are erythrocytes – Red Blood Cells (RBCs). Due to their size they are easy to observe using microscopy. It is commonly known that the shape and lifetime of RBCs allows for early disease identification. Authors present special measurement system for RBCs fluctuations...
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Dielectric Barrier Discharge Systems with HV Generators and Discharge Chambers for Surface Treatment and Decontamination of Organic Products
PublicationThe article presents applications of systems with power electronic converters, high voltage transformers, and discharge chambers used for nonthermal, dielectric barrier discharge plasma treatment of a plastic surface and decontamination of organic loose products. In these installations, the inductance of the high voltage transformers and the capacitances of the electrode sets form resonant circuits that are excited by inverters....
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Standards on Cyber Security Assessment of Smart Grid
PublicationSecurity evaluation of communication systems in smart grid poses a great challenge to the developers and operators. In recent years many new smart grid standards were proposed, which paradoxically results in the difficulty in finding a relevant publication in this plethora of literature. This paper presents the results of a systematic analysis which aimed at addressing this issue by identifying standards that present sound security...
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REGULATION OF CELLULAR REDOX HOMEOSTASIS BY (-)-EPICATECHIN AND COCOA EXTRACTS – PILOT STUDY
PublicationCocoa polyphenols play an important role in protection against diseases in which oxidative stress is implicated as a causal or contributing factor. The main aim of this study was to elucidate the influence of different cocoa extracts and main cocoa bioactive compound (–)-epicatechin on cell growth and support of antioxidant cellular barrier in colon adenocarcinoma cell line model (HT29). Results show that the tested cocoa bioactivity...
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Regulation of Cellular Redox Homeostasis by (–)-Epicatechin and Cocoa Extracts—A Pilot Study
PublicationCocoa polyphenols play an important role in protection against diseases in which oxidative stress is implicated as a causal or contributing factor. The main aim of this study was to elucidate the influence of different cocoa extracts and main cocoa bioactive compound (–)-epicatechin on cell growth and support of antioxidant cellular barrier in colon adenocarcinoma cell line model (HT29). Results show that the tested cocoa bioactivity...
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A method for testing the wide-sense stationary uncorrelated scattering assumption fulfillment for an underwater acoustic channel
PublicationWide-sense stationary and uncorrelated scattering (WSSUS) assumptions are often applied for the statistical description of wireless communication channels. However, in the case of underwater acoustic channels the WSSUS model is of limited value. The degree of similarity of in-phase and quadrature components of the channel impulse response, measured with the use of bandpass modulated signals, can be used as an indicator of WSSUS...
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REALIZACJA PRÓBNIKA SYSTEMU REJESTROWANIA I MONITOROWANIA PARAMETRÓW JAKOŚCIOWYCH STOSUJĄCEGO STANDARD IPFIX
PublicationNadzór parametrów jakościowych w sieci z protokołem IP jest jedną z ważniejszych funkcji jaką musi dysponować Operator sieci telekomunikacyjnej. W pracy przedstawiono koncepcję systemu rejestracji i monitorowania przeznaczonego do realizacji tego celu. Jest to rozwiązanie pasywne stosujące rozszerzenie standardu IPFIX, które określono mianem SIPFIX. Opisano praktyczną realizację i wyniki testów Próbnika, jednego z podstawowych...
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Mechanizmy bezpieczeństwa transmisji w systemie netBaltic
Publicationartykule zaprezentowano założenia dotyczące zabezpieczania węzłów sieci realizowanej w ramach systemu netBaltic. Ze względu na dużą różnorodność rozważanych mechanizmów komunikacyjnych architektura bezpieczeństwa została podzielona na kilka elementów – infrastrukturę klucza publicznego (PKI), bezpieczeństwo systemowe węzłów, zabezpieczanie komunikacji w modelu samoorganizującej wieloskokowej sieci kratowej, a także sieci niewrażliwej...
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Underground Water Level Prediction in Remote Sensing Images Using Improved Hydro Index Value with Ensemble Classifier
PublicationThe economic sustainability of aquifers across the world relies on accurate and rapid estimates of groundwater storage changes, but this becomes difficult due to the absence of insitu groundwater surveys in most areas. By closing the water balance, hydrologic remote sensing measures offer a possible method for quantifying changes in groundwater storage. However, it is uncertain to what extent remote sensing data can provide an...
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A model for agribusiness supply chain risk management using fuzzy logic. Case study: Grain route from Ukraine to Poland
PublicationIn order to establish new logistics routes, it is necessary to address several technical and organizational issues, among others. One of the most important criteria for evaluating the performance of a supply chain is the delivery time, proactive consideration of potential hazards and associated uncertainties that may occur along the route. However, the existing solutions are often passive and reactive, based on statistics, thus...
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System subwencjonowania jednostek samorządu terytorialnego w Polsce: dysfunkcje i pożądane kierunki racjonalizacji
PublicationMonografia poświęcona jest problematyce racjonalizacji subwencjonowania samorządu terytorialnego w Polsce. Jej głównym celem jest określenie roli i znaczenia subwencji w systemie finansowym jednostek samorządu terytorialnego. Za dysfunkcje w największym stopniu zniekształcające system subwencjonowania uznano: ― brak powiązania globalnej kwoty subwencji ogólnej ze składowymi budżetu państwa, ― pomijanie, przy ocenie potencjału...
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Wpływ polietylenu szczepionego bezwodnikiem maleinowym oraz sił ścinających na właściwości mieszanin polietylen wysokiej gęstości-miał gumowy
PublicationScharakteryzowano wpływ kompatybilizatora w postaci polietylenu szczepionego bezwodnikiem maleinowym na właściwości mieszanin PE-HD–miał gumowy. Kompozycje termoplastyczne zawierające 50 cz. mas. rozdrobnionych odpadów gumowych, otrzymano przy użyciu współbieżnej wytłaczarki dwuślimakowej. Poziom sił ścinających generowanych podczas mieszania, regulowano za pomocą zmian prędkości obrotowych ślimaków. Przeprowadzono charakterystykę...
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Architektura bezpieczeństwa systemu netBaltic
PublicationW artykule zaprezentowano założenia dotyczące zabezpieczania węzłów sieci realizowanej w ramach systemu netBaltic. Ze względu na dużą różnorodność rozważanych mechanizmów komunikacyjnych architektura bezpieczeństwa została podzielona na kilka elementów – infrastrukturę klucza publicznego (PKI), bezpieczeństwo systemowe węzłów, zabezpieczanie komunikacji w modelu samoorganizującej wieloskokowej sieci kratowej, a także sieci niewrażliwej...
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Uczelnia organizacją z domieszka turkusu - sznasa czy iluzja?
PublicationPo kilkuletnich dyskusjach nad przyszłym kształtem szkolnictwa wyższego w Polsce, zarówno na poziomie systemowym, jak i instytucjonalnym, w 2018 r. uchwalono ustawę Prawo o szkolnictwie wyższym i nauce, zwaną dalej Ustawą (2018). Regulacja ta wraz z pakietem rozporządzeń poszerzyła autonomię uczelni w zakresie organizacyjno-zarządczym, jednocześnie potęgując znaczenie ich rozliczalności. Wzmocnienie władzy rektora spowodowało zmianę...
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Modyfikacja cementu kostnego w celu uzyskania długotrwałej ochrony antybakteryjnej
PublicationNiniejsza rozprawa doktorska stanowi przewodnik po jednotematycznym cyklu publikacji, dotyczącym modyfikacji akrylowego cementu kostnego celem uzyskania długotrwałej i efektywnej ochrony antybakteryjnej. W ramach niego przeprowadzono badania eksperymentalne polegające na opracowaniu technologii wytwarzania modyfikowanego cementu kostnego oraz procedury medycznej jego stosowania. Cement kostny był modyfikowany przez zastosowanie...
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An adaptive approach to non-destructive evaluation (NDE) of cast irons containing precipitated graphite particles with the help of magnetoacoustic emission
PublicationPhysical properties of cast irons strongly depend on both their microstructure and the presence of casting defects. The paper analyses the possibility of application of magnetoacoustic emission (MAE) for nondestructive detection of flawed cast iron components. The investigated samples containing dross, chunky graphite and lamellar graphite were compared with the reference, flawless, spheroidal cast iron sample. The optimisation...
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Modified SPWM Technique with Zero-Sequence Voltage Injection for a Five-Phase, Three-Level NPC Inverter
PublicationThis article presents a modified sinusoidal pulse-width modulation (SPWM) scheme for a five-phase, three-level neutral-point-clamped inverter. The modulation scheme deploys a modified min–max function to inject the zero-sequence components into the reference modulating signals; hence enabling the effective utilization of the DC-link voltage. Balanced split-input DC-link voltages were achieved through further incorporation of adjustable...
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Data Partitioning and Task Management in the Clustered Server Layer of the Volunteer-based Computation System
PublicationWhile the typical volunteer-based distributed computing system focus on the computing performance, the Comcute system was designed especially to keep alive in the emergency situations. This means that designers had to take into account not only performance, but the safety of calculations as well. Quadruple-layered architecture was proposed to separate the untrusted components from the core of the system. The main layer (W) consists...
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A novel method of time-frequency analysis: an essential spectrogram
PublicationA novel precise method of time-frequency analysis is presented. In the algorithm, a new energy distribution is estimated by simultaneously discard or displacement of the classical spec- trogram energy. A channelized instantaneous frequency and a local group delay are used in order to replacement in the same manner as formulated by Kodera et al. [1, 2]. Additionally, new representations: a channelized instantaneous bandwidth and...
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Usage of concentrated spectrogram for analysis of acoustical signals
PublicationA novel precise method of signal analysis in the time-frequency domain is presented. A signal energy distribution is estimated by discard and displacement of energy parts of the classical spectrogram. A channelized instantaneous frequency and a local group delay are used in order to energy replacement. Additionally, newly introduced representations such as: a channelized instantaneous bandwidth and a local group duration are used...
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Analyzing the Geometry of the Turnouts and Their Adjustment Basing on the Tacheometer Measurements
PublicationThe article presents the results of tacheometric measurements of a station throat, as well as the method of data preparation and analysis. The calculations covered the verification of the geometry and the location of railway turnouts and crossings. The analyses were performed for the selected parameters of the turnout geometry, including their lengths and track gauge in main sections. In addition, the data were analyzed to confirm...
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Uncertainty estimation of loop impedance measurement determined by the vector method
PublicationThis article presents a detailed analysis of uncertainty estimation of loop impedance measurement determined by the vector method. The analysis includes the following estimates: resistance variance, voltage variance and time measurement variance. This paper presents a methodology for estimating the combined standard uncertainty of loop impedance by the vector method. The vector method allows to determine loop impedance based on...
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Evaluation of Wear Resistance of Ti alloys used for elements friction of knee endoprosthesis
PublicationThe paper presents research results of resistance to abrasive wear of titanium alloys: Ti6Al4V (commonly used) and Til3Nb13Zr (alloy of new generation) in association with polyethylene (UHMW-PE) predisposed for elements on pair of the knee endoprosthesis. The results were analysed from the point of possibility of an use of new generation titanium alloys as components of such implants. The tests of resistance to abrasive wear of...
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Software tool for modelling of mechatronic systems with elastic continua
PublicationThe paper presents a systematic computational package for modelling and analysis of complex systems composed of multiple lumped and distributed parameter subsystems. The constructed computer program enables the frequency domain analysis of a class of linear systems and to obtain reduced order model in the form of bond graph. Obtained modal bond graph can be directly exported into 20-Sim package to further processing including nonlinear...
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Higher harmonics produced by traction substations – computer modelling and experimental verification
PublicationVoltage and current harmonics have a detrimental effect on the components of a power system. Current harmonics may result in the overload and damage to power transformers, although the rms value of load current does not exceed their current-carrying capacity. Voltage harmonics may result in, for example, damage to capacitor banks used to compensate reactive power. Devices which contribute to both current and voltage distortion...
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Raman spectroscopic investigation of blood and related materials
PublicationThis paper reports preliminary studies on use of Raman spectroscopy for investigation of blood. High quality blood spectra were recorded in-vitro with excitation wavelengths of 830 nm. Because of complex composition of the blood as well as by light attenuation and scattering in the tissues, spectra set up from wide, low-intensive Raman bands and intensive optical background. To get information about origin of bands in Raman spectra...
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Wideband Modeling of DC-DC Buck Converter with GaN Transistors
PublicationThe general wideband modeling method of the power converter is presented on the example of DC-DC buck converter with GaN High Electron Mobility Transistors (HEMT). The models of all basic and parasitic components are briefly described. The two methods of Printed Circuit Board (PCB) layout parameter extraction are presented. The results of simulation in Saber@Sketch simulation software and measurements are compared. Next, the model...
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EFFICIENCY OF HEALTHCARE SYSTEMS IN EUROPEAN COUNTRIES - THE DEA NETWORK APPROACH
PublicationHealthcare systems in Europe are constantly undergoing reforms which adapt them to social, economic and political requirements. The aim of this article is to examine the efficiency of healthcare systems in 30 European countries in 2014. The Network Data Envelopment Analysis (NDEA) model was used. The efficiency of the countries’ overall health systems and their two main components were examined: the public health system and the...