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Search results for: PHASE-TYPE DISTRIBUTIONS
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New type T-Source inverter
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Type of surface and tire rolling resistance
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Crystal growth of CsCl-type Yb0.24Sn0.76Ru
PublicationWzrost kryształów o stechiometrii Yb0.24Sn0.76Ru został przeprowadzony metodą topnikową. Kryształy poddano badaniom dyfrakcyjnym a także mikroskopii elektornowej. Yb0.24Sn0.76Ru krystalizuje w sześciennej strukturze typu chlorku cezu (CsCl).
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Displacement control in PWK-type pumps
PublicationW referacie zaprezentowano konstrukcję mechanizmu sterowania wydajnością zastosowanego w pompach z rozrządem krzywkowym typu PWK. Przedstawiono wyniki wstępnych badań prototypu PWKZ-78 oraz komputerową analizę zjawisk zachodzących w komorze cylindrowej pompy.
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Crystal growth of CsCl-type Yb0.24Sn0.76Ru
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Displacement control in PWK-type pumps
PublicationThe most important, strategic goal however is creation of the variable displacement version of the new pump PWK. Thanks to full discharge of it's commutation mechanism from hydrostatic forces the variable pump can be directly controlled by low-energy actuator like proportional electromagnet or stepping motor. It means that costly and complicated hydraulic servomechanism (applied in all present variable displacement pumps) is no...
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Taylor type predictor for pressure changes
PublicationCelem pracy jest ocena predykcji ciśnienia za pomocą rozwinięcia funkcji w szereg Taylora. Przewidywana wartość ciśnienia jest obliczana jako iloczyn wcześniejszych wartości mnożonych przez współczynniki wagowe wyznaczone w oparciu o szereg Taylora. Zaletą takiego podejścia jest możliwość analizy danych próbkowanych nierównomiernie. Podstawową wadą jest założenie, że ciśnienie jest dobrze aproksymowane przez wielomian niskiego...
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Conley type index and hamiltonian inclusions
PublicationOpisano definicję i własności indeksu dla zbiorów niezmienniczych wielowartościowego układu dynamicznego w nieskończenie-wymiarowej przestrzeni Hilberta. Podano nowe przykłady zastosowań do twierdzeń o istnieniu nietrywialnych rozwiązań okresowych układów hamiltonowskichz prawą stroną niegładką.
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New type T-Source inverter
PublicationThis paper presents different topologies of voltage inverters with alternative input LC networks. The basic topology is known in the literature as a Z-source inverter (ZSI). Alternative passive networks were named by the authors as T-sources. T-source inverter has fewer reactive components in comparison to conventional Z-source inverter. The most significant advantage of the T-source inverter (TSI) is its use of a common voltage...
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Personality Type and Neural Circulatory Control
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Bernstein-type theorem for ϕ-Laplacian
PublicationIn this paper we obtain a solution to the second-order boundary value problem of the form \frac{d}{dt}\varPhi'(\dot{u})=f(t,u,\dot{u}), t\in [0,1], u\colon \mathbb {R}\to \mathbb {R} with Sturm–Liouville boundary conditions, where \varPhi\colon \mathbb {R}\to \mathbb {R} is a strictly convex, differentiable function and f\colon[0,1]\times \mathbb {R}\times \mathbb {R}\to \mathbb {R} is continuous and satisfies a suitable growth...
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Determination of leakage inductances of multi-winding and single-phase transformer
PublicationThis paper presents the method for determination of leakage inductances of single-phase and multi-winding transformer. The matrix of leakage inductances takes into account leakage self and also leakage mutual magnetic couplings. It is assumed that there is a flux common to all windings and several leakage fluxes referred to a particular winding. The flux linkages of each coil needed fo calculation of leakage inductances was computed...
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Two-phase flow in heterogeneous porous media with non-wetting phase trapping
PublicationThis article presents amathematical model describing flowof two fluid phases in a heterogeneous porous medium. Zaproponowano model matematyczny przepływu dwufazowego w drobnoziarnistym ośrodku porowatym zawierającym inkluzje gruboziarniste. Inkluzje charakteryzują się niższą wartością ciśnienia wejścia dla płynu niezwilżającego (np. powietrze, ropa naftowa) niż materiał podstawowy. Podczas nawadniania takiego ośrodka dochodzi do...
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Sensorless Disturbance Detection for Five Phase Induction Motor with Third Harmonic Injection
PublicationThe paper presents a sensorless disturbance detection procedure that was done on a five phase induction motor with third harmonic injection. A test bench was developed where a three phase machine serves as disturbance generator of different frequencies. The control of the machines is based on multi scalar variables that ensures an independent control of the motor EMF and the rotor flux. For disturbance identification a speed observer...
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Numerical Simulations of Seepage in Dikes Using unsaturated and Two-Phase Flow Models
PublicationModeling of water flow in variably saturated porous media, including flood dikes, is often based on the Richards equation, which neglects the flow of pore air, assuming that it remains at constant atmospheric pressure. However, there is also evidence that the air flow can be important, especially when the connectivity between the pore air and atmospheric air is lost. In such cases a full two-phase air-water flow model should be...
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Phase change thermal energy storage – the experience of the materials preparation for the specific applications.
PublicationThermal energy storage and temperature stabilization is very important in many engineering applications. There are three kinds of thermal energy storage: sensible heat, latent heat and reversible chemical reaction heat. Phase change materials (PCM) absorb, store and release large amounts of energy in the form of latent heat, at constant temperature, called the transition temperature. Many innovative applications could be found...
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Radar Signal Parameters Estimation Using Phase Accelerogram in the Time-Frequency Domain
PublicationRadar signal parameter estimation, in the context of the reconstruction of the received signal in a passive radar utilizing other radars as a source of illumination, is one of the fundamental steps in the signal processing chain in such a device. The task is also a crucial one in electronic reconnaissance systems, e.g. ELINT (Electronic Intelligence) systems. In order to obtain accurate results it is important to measure, estimate...
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Design, modelling and analysis of a new type of piezoelectric motor. Multicell piezoelectric motor
PublicationThis paper describes a new type of piezoelectric motor. The results, obtained in the field of piezoelectric motors, have pointed out that these motors have potentially high possibilities in the future special applications. The research work presents the design, simulations and parameters of the piezoelectric motor with three rotation-mode actuators. The motor is characterized by a high power, relative high speed and torque. The...
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Styrene Oxidation by Copper(II) Complexes Salen-Type Encapsulated into Nay Zeolite
PublicationThe copper(II) complex with a Schiff-base salen-type ligand has been encapsulated in the nanopores of a NaY zeolite by using two different methodologies, the flexible ligand and in situ complex preparation methods. The encapsulated and non-encapsulated copper(II) complexes were screened as catalysts for styrene oxidation by using TBHP as the oxygen source in acetonitrile solvent. Under the optimized conditions, the catalysts exhibited...
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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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Representation of magnetic hysteresis in a circuit model of a single-phase transformer
PublicationThe paper presents a mathematical model for the hysteresis phenomenon in a multi-winding single-phase core type transformer. The set of loop differential equations was developed for K-th winding transformer model where the flux linkages of each winding includes a flux common Φ to all windings as function of magneto motive force Θ of all windings. The first purpose of this paper is to determine a hysteresis nonlinearity involved...
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Improvements to the two-phase sandwich method for calculating the melting points of pure metals
PublicationThe thermophysical properties of metal alloys are often investigated via molecular dynamics (MD) simulations.An exact and reliable estimation of the thermophysical parameters from the MD data requires a properly and carefullyelaborated methodology. In this paper, an improved two-phase sandwich method for the determination of the metal meltingtemperature is proposed, based on the solid-liquid equilibrium theory. The new method was...
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Testing Stability of Digital Filters Using Multimodal Particle Swarm Optimization with Phase Analysis
PublicationIn this paper, a novel meta-heuristic method for evaluation of digital filter stability is presented. The proposed method is very general because it allows one to evaluate stability of systems whose characteristic equations are not based on polynomials. The method combines an efficient evolutionary algorithm represented by the particle swarm optimization and the phase analysis of a complex function in the characteristic equation....
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A Theoretical and Experimental Study of Moderate Temperature Alfa Type Stirling Engines
PublicationThe Stirling engine is a device that allows conversion of thermal energy into mechanical energy with relatively high efficiency. Existing commercial designs are mainly based on the usage of high temperature heat sources, whose availability from renewable or waste heat sources is significantly lower than that of moderate temperature sources. The paper presents the results of experimental research on a prototype alpha type Stirling...
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Five-phase squirrel-cage motor. Construction and drive properties
PublicationThis paper presents the simulation and experimental results of a five-phase squirrel-cage induction motor. The new machine has been designed to operate in a drive system with third harmonic rotor flux injection in order to improve the motor torque utilization. The motor structure, the mathematical model as well as the laboratory prototype have been described. The motor speed-torque characteristics and transients are elaborated...
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Comparison of Transmission Capacities of Two Regulation Systems: Lateral and in-phase Control Transformers
PublicationThis paper presents a comparison of regulation capabilities of lateral and in-phase control transformers in a selected node of a power system. Their regulation capabilities are presented, as well as cross-system exchange options.
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3-phase medium frequency transformer for a 100kW 1.2kV 20kHz Dual Active Bridge converter
PublicationThe article presents a three-phase Medium Frequency Transformer being a part of a 100kW 1.2kV 20kHz Dual Active Bridge DC-DC converter. The transformer design is detailed focusing on winding and core power loss calculation. The high power three-phase MFT prototype is presented. The experimental results include the transformer impedance characteristics, no load test and three-phase DAB full load test waveforms
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Fatigue Performance of Double-Layered Asphalt Concrete Beams Reinforced with New Type of Geocomposites
PublicationThe reinforcement of asphalt layers with geosynthetics has been used for several decades, but proper evaluation of the influence of these materials on pavement fatigue life is still a challenging task. The presented study investigates a novel approach to the reinforcement of asphalt layers using a new type of geogrid composite, in which square or hexagonal polypropylene stiff monolithic paving grid with integral junctions is bonded...
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Solventless sample preparation techniques based on solid- and vapour-phase extraction
PublicationThe main objective of this review is to critically evaluate recent developments in solventless sample preparation techniques. The potential of a variety of sample preparation techniques based on solid- and vapour-phase extraction techniques is evaluated. Direct thermal extraction and derivatization processes to facilitate the extraction of analytes in different areas are included. The applicability, disadvantages and advantages...
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Investigation of changes in the type B PLC effect of Al–Mg–Cu type alloy for various strain rates
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Investigation of changes in the type B PLC effect of Al-Mg-Cu type alloy for various strain rates
PublicationEfekt Portevina-LeChateliera ujawnia się w postaci skokowych zmian naprężenia w trakcie procesu odkształcenia próbek pewnych stopów. Zjawisko PLC występuje w kilku odmianach charakteryzujących się istotnymi różnicami zarówno w przestrzennym rozkładzie pasm odkształcenia jak też przebiegu krzywej naprężeniowej. Przebiegi odpowiadające różnym odmianom serration charakteryzują się odmiennymi właściwościami rozkładu energetycznego...
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Sensorless Multiscalar Control of Five-Phase Induction Machine with Inverter Output Filter
PublicationThe paper presents a complete solution for speed sensorless control system for five-phase induction motor with voltage inverter, LC filter and nonlinear control of combined fundamental and third harmonic flux distribution. The control principle, also known as multiscalar control, nonlinear control or natural variables control, is based on a use of properly selected scalar variables in control feedback to linearize controlled system....
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Kinetics of Intermetallic Phase Precipitation in Manual Metal Arc Welded Duplex Stainless Steels
PublicationThe article presents the influence of heat treatment on the kinetics of transformations in lean duplex LDX2101 steel and a weld made of standard duplex 2209 material, which was welded by manual metal arc welding. Changes in the microstructure, hardness, and magnetic phase content were analyzed after heat treatment was conducted at a temperature of 800 °C for a period ranging from 15 to 1440 min. Light and scanning microscopy, Vickers...
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Size Exclusion Coupled to Reversed Phase Liquid Chromatography for the Characterization of Cranberry Products
PublicationA combination of solvent extraction, size exclusion purification, and reversed-phase liquid chromatography with UV absorption and fluorescence detection was here used for the determination of flavan-3-ols and related oligomeric compounds in cranberry products. The method relied on robust, simple, and inexpensive instrumental equipment present in most of routine analytical laboratories. Sample extracts in methanol/water/hydrochloric...
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Investigation of optical properties of Infitec and Active Stereo stereoscopic techniques for CAVE-type virtual reality systems
PublicationIn recent years, many scientific and industrial centres in the world developed virtual reality systems or laboratories. At present, among the most advanced virtual reality systems are CAVE-type (Cave Automatic Virtual Environment) installations. Such systems usually consist of four, five, or six projection screens arranged in the form of a closed or hemi-closed space. The basic task of such systems is to ensure the effect of user...
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Compact 4 × 4 butler matrix with non‐standard phase differences for IoT applications
PublicationButler matrices represent a popular class of feeding networks for antenna arrays. Large dimensions and the lack of flexibility in terms of achievable output phase difference make conventional Butler structures of limited use for modern communication devices. In this work, a compact planar 4 × 4 matrix with non-standard relative phase shifts of –30º, 150º, –120º, and 60º has been proposed. The structure is designed to operate at...
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Machine-learning-based precise cost-efficient NO2 sensor calibration by means of time series matching and global data pre-processing
PublicationAir pollution remains a considerable contemporary challenge affecting life quality, the environment, and economic well-being. It encompasses an array of pollutants—gases, particulate matter, biological molecules—emanating from sources such as vehicle emissions, industrial activities, agriculture, and natural occurrences. Nitrogen dioxide (NO2), a harmful gas, is particularly abundant in densely populated urban areas. Given its...
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Optimization-Based Robustness Enhancement of Compact Microwave Component Designs with Response Feature Regression Surrogates
PublicationThe ability to evaluate the effects of fabrication tolerances and other types of uncertainties is a critical part of microwave design process. Improving the immunity of the device to parameter deviations is equally important, especially when the performance specifications are stringent and can barely be met even assuming a perfect manufacturing process. In the case of modern miniaturized microwave components of complex topologies,...
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Solid phase microextraction: state of the art, opportunities and applications
PublicationSolid phase microextraction is one of the most popular green techniques used for sample preparations in analytical chemistry. It is a simple, rapid, sensitive, and solvent-free technique. Since SPME was first introduced in the early 1990s, there has been an intensification of research in order to elaborate new methodical solutions in many research facilities around the world, which could increase the use of this technique. More...
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The Corporate Museum: A New Type of Museum Created as a Component of Marketing Company
PublicationA new type of museum appeared – the corporate museum. The museum institution in this instance has been used as a new marketing device for building corporate identity strategies. Their inception is not based on the existing context of a place, but appears to be integrated with the corporate identity program, exposing the company’s values and philosophy. The corporate museums are thematic, commercial buildings, owned by a particular...
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Measurement method for capacitive sensors for microcontrollers based on a phase shifter
PublicationA complete measurement method dedicated to capacitive sensors has been developed. It includes the development of hardware (an analogue interface circuit for microcontrollers with built-in times/counters and analogue comparators) and software (a measurement procedure and a systematic error calibration (correction) algorithm which is based on a calibration dictionary). The interface circuit consists of a low-pass filter and a phase...
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Three-dimensional visualization and measurement of conformal dose distributions using magnetic resonance imaging of bang polymer gel dosimeters
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A Linear Phase Filter in Quadruplet Topology With Frequency-Dependent Couplings
PublicationThis letter presents a design of a linear phase microwave bandpass filter. The filter is composed of four resonators arranged in the quadruplet topology. Making the cross and one direct coupling dispersive gives additional design flexibility. The first advantage of using frequency-dependent couplings is the possibility to chose an arbitrary location of a pair of complex transmission zeros (TZs) in the s-domain. The second one is...
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Modern trends in solid phase extraction: New sorbent media
PublicationBased on the recently published literature, this review provides an update of the most important features and application of formats and devices employed in solid phase extraction (SPE). Special attention was paid on new trapping media proposed in SPE prior the chromatography analysis, based on the use of nanostructured materials, including carbon nanomaterials, electrospun nanofibers, dendrimes and magnetic nanoparticles, molecular...
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FPGA Acceleration of Matrix-Assembly Phase of RWG-Based MoM
PublicationIn this letter, the field-programmable-gate-array accelerated implementation of matrix-assembly phase of the method of moments (MoM) is presented. The solution is based on a discretization of the frequency-domain mixed potential integral equation using the Rao-Wilton-Glisson basis functions and their extension to wire-to-surface junctions. To take advantage of the given hardware resources (i.e., Xilinx Alveo U200 accelerator card),...
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Flow Boiling in Minigap in the Reversed Two-Phase Thermosiphon Loop
PublicationThe paper presents the results of experimental investigations of a model of a heat exchanger featuring a minigap, which is perceived as an evaporator for an inverted thermosiphon. The system works with a single component test fluid. The tested evaporator generates pumping power in the test loop in a way similar to the mammoth pump. The tests regarded a module of the heat exchanger, consisting of a hot leg and a cold leg with the...
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Separation of toluene from gas phase using supported imidazolium ionic liquid membrane
PublicationInvestigation on utilization of supported ionic liquids membranes for hydrocarbon separation from the gas phase was performed. Properties of membrane phase, wettability of supports, swelling effects and solubility of toluene were taken into account. Toluene permeation rates were significantly higher than those of pure nitrogen, the selectivity in a range of 17–341 was satisfying for separation. Despite the increase of viscosity...
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Selection of C-Type Filters for Reactive Power Compensation and Filtration of Higher Harmonics Injected into the Transmission System by Arc Furnaces
PublicationThis article presents a method for selecting the elements of a C-type filter working with a conventional LC-type filter for compensating reactive power and filtering out higher harmonics generated by arc furnaces and ladle furnaces. The study was conducted in a steel mill supplied by a 110 kV transmission system, where higher harmonic currents and nonlinear loads were measured. A series of computer simulations were performed under...
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Thermophysical properties of the phase change material mixtures – preliminary studies on macromolecular hydrocarbons example.
PublicationThe aim of this work is a theoretical and experimental analysis of the macromolecular hydrocarbon mixtures composition and the impact on thermophysical parameters of the phase change materials (PCM) made from these mixtures. The analysis of the current state of knowledge extended by the author’s own studies have been presented. Thermophysical characteristics of the hydrocarbons and their mixtures have been specified, in such a...
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Thermophysical Properties of the Phase Change Material Mixtures – Preliminary Studies on Macromolecular Hydrocarbons Example.
PublicationThe aim of this work is a theoretical and experimental analysis of the macromolecular hydrocarbons mixtures composition and the impact on thermophysical parameters of the phase change materials (PCM) made from these mixtures. The analysis of the current state of knowledge extended by the author's own studies have been presented. Thermophysical characteristics of the hydrocarbons and their mixtures have been specified, in such a...