Wyniki wyszukiwania dla: FIELD OF STUDY
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Characterization of fracture process in polyolefin fibre-reinforced concrete using ultrasonic waves and digital image correlation
PublikacjaThis study explores the monitoring of the fracture process in concrete beams and aims to characterize the evolution of damage in polyolefin fibre-reinforced concrete beams by utilizing the integrated application of two measurement techniques, digital image correlation and ultrasonic testing. The interpretation of registered wave time histories data was provided by the calculation of the magnitude-phase-composite metrics. An efficient...
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Local variability in snow concentrations of chlorinated persistent organic pollutants as a source of large uncertainty in interpreting spatial patterns at all scales
PublikacjaSingle point sampling, a widespread practice in snow studies in remote areas, due to logistical constraints, can present an unquantified error to the final study results. The low concentrations of studied chemicals, such as chlorinated persistent organic pollutants, contribute to the uncertainty. We conducted a field experiment in the Arctic to estimate the error stemming from differences in the composition of snow at short distances...
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Workbook for cooperative development of personnell and organisation for innovation in SME in the Baltic Sea Region
PublikacjaThis study highlights the potential for cooperative development of personnel and organisational innovations in SMEs and gives an example implemented by the University of Lund together with the Municipality of Astorp and local companies. This innovation field is of particular importance for all companies in the region, since it does apply to any professional sector, be it a service oriented company or a manufacturing business. This...
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HYGRO-MAGNETIC VIBRATION OF THE SINGLE-WALLED CARBON NANOTUBE WITH NONLINEAR TEMPERATURE DISTRIBUTION BASED ON A MODIFIED BEAM THEORY AND NONLOCAL STRAIN GRADIENT MODEL
PublikacjaIn this study, vibration analysis of single-walled carbon nanotube (SWCNT) has been carried out by using a refined beam theory, namely one variable shear deformation beam theory. This approach has one variable lesser than a contractual shear deformation theory such as first-order shear deformation theory (FSDT) and acts like classical beam approach but with considering shear deformations. The SWCNT has been placed in an axial or...
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State of the art in the field of emission reduction of sulphur dioxide produced during coal combustion
PublikacjaThe need for clean coal technologies to reduce the adverse environmental impact of coal combustion products has been grounded. The article deals with information concerning present and future technologies, directed towards the struggle against air pollution by SO2, produced during coal combustion. Their classification and critical rating from economical and technological points of views (including those developed by authors) have...
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Propagation in the Open Cylindrical Guide of Arbitrary Cross Section With the Use of Field Matching Method
PublikacjaA simple solution to propagation problem in open waveguides and dielectric fibers of arbitrary convex cross section is presented. The idea of the analysis is based on the direct field matching technique involving the usage of the field projection at the boundary on a fixed set of orthogonal basis functions. A complex root tracing algorithm is utilized to find the propagation coefficients of the investigated guides. Different convex...
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Spectral analysis of nonstationary low-frequency magnetic-field emissions from ship's power
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Application of matching pursuit based method to identify sources of time-vary magnetic field
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Numerical Simulation of Temperature Field in Steel under Action of Electron Beam Heating Source
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Magnetic field gradient as the most useful signal for detection of flaws using MFL technique
PublikacjaThe magnetic flux leakage (MFL) technique is extensively used for detection of flaws as well as for evaluation of their dimensions in ferromagnetic materials. However, proper analysis of the MFL signal is hindered by the MFL sensor velocity causing distortions of this signal. Traditionally measured components of the MFL signal are particularly sensitive to the scanning velocity. In this paper, an another signal – the gradient of...
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Electric field and charge induced quenching of luminescence in electroluminescent emitters based on lanthanide complexes
PublikacjaW pracy badano ładunkowe i elektrycznopolowe wygaszanie ekscytonóww układzie dwuamina TPD: organiczny kompleks europu przez pomiar zaników fotoluminescencji w zewnętrznym polu elektrycznym.
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Numerical Estimate of the Spectral Resonance Structure Frequency Scale of Natural ULF Magnetic Field
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Geomagnetic Storms and Substorms as Space Weather I nfluence on Atmospheric Electric Field Variations
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Simplified method of simulation of temperature field control system of induction heated calender rolls
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Dynamic Formation and Breaking of Disulfide Bonds in Molecular Dynamics Simulations with the UNRES Force Field
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Replica Exchange and Multicanonical Algorithms with the Coarse-Grained United-Residue (UNRES) Force Field
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Antimicrobial properties of pristine and Pt-modified titania P25 in rotating magnetic field conditions
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Exploring perceptions of pro environmental educational mobile applications based on semantic field analysis
PublikacjaThe paper aims to identify multidimensional perceptions of mobile apps by their users. Special attention has been paid to pro-environmental educational apps. Semantic field analysis and measurement of emotional temperatures were performed to achieve this goal. Transcripts from seven focus group interviews were used as research material. The results indicate that functionality based on a reward or benefit system reinforces environmentally...
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Analysis of Reliability Structures for Fire Signaling Systems in the Field of Fire Safety and Hardware Requirements
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Large electric field effects on photoluminescence of organic Eu3+ complex-based electroluminescent emitters
PublikacjaW pracy zaobserwowano silne wygaszenie fotoluminescencji pod wpływem zewnętrznego pola elektrycznego w organicznym kompleksie europu Eu(III). Wygaszenie fotoluminescencji przypisano elektrycznopolowej dysocjacji ekscytonów oraz anihilacji ekscytonów na wstrzykniętym do próbki ładunku elektrycznym.
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Propagation in a ferrite circular waveguide magnetized through a rotary four-pole magnetic field
PublikacjaOpracowano uproszczony model matematyczny użyteczny do badania zjawisk polowych występujących w falowodzie cylindrycznym magnesowanym czterobiegunowym polem obrotowym. Wykazano, że falowód ten może być wykorzystany jako przesuwnik fazy lub układ zmieniający polaryzację.
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Acoustic field and the entropy mode induced by it in a waveguide filled with some non-equilibrium gases
PublikacjaThe non-linear propagation of an acoustic beam in a rectangular waveguide is considered. The medium of sound propagation, is a gas where thermodynamically non-equilibrium processes take place: such as exothermic chemical reactions or excitation of vibrational degrees of a molecule’s freedom. The incident and reflected compounds of the acoustic field do not interact in the leading order in the case of periodic weakly nonlinear sound...
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The adaptive backstepping control of PMSM supplied by current source inverter for the field weakening region
PublikacjaThe sensorless control system of permanent magnet synchronous motor PMSM supplied by current source inverter for field weakening operation is presented in this paper. The adaptive backstepping control system and the backstepping speed observer are presented. The control system is based on multi-scalar variables. The control variables are: dc-link voltage and the output current vector pulsation. The control system was named voltage...
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Numerical tests of time-stepping schemes in the context of FEM for 6-field shell dynamics
PublikacjaThe paper deals with integration of dynamic equations of irregular shells performed with relatively long time steps. Numerical instability appearing often in this kind of analysis motivated the authors to present some studies based on numerical tests referring to convergence problems of finite element analysis as well the applied stability conditions. The analysis is carried out on simulations of shell dynamics with the where the...
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Detection and localization of selected acoustic events in 3D acoustic field for smart surveillance applications
PublikacjaA method for automatic determination of position of chosen sound events such as speech signals and impulse sounds in 3-dimensional space is presented. The events are localized in the presence of sound reflections employing acoustic vector sensors. Human voice and impulsive sounds are detected using adaptive detectors based on modified peak-valley difference (PVD) parameter and sound pressure level. Localization based on signals...
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Analysis of magnetic field distribution inside ferromagnetic thin shells during degaussing process
PublikacjaAnalysis of the demagnetization of a large ferromagnetic object like a ship, was conducted. The approximate mathematical model in the form of a long cylindrical shell of constant magnetic permeability was applied. The discrete degaussing winding was assumed and the current density and magnetic flux density distribution in the ferromagnetic shell wall were determined. Based on the frequential and temporal analysis the recommended...
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Stress anisotropy characterisation with the help of Barkhausen effect detector with adjustable magnetic field direction
PublikacjaIn the paper we describe a novel apparatus for the measurement of the Barkhausen noise (BN) angular dependence, which in turn may be indicative of the stress induced anisotropy of magnetic properties. Such dependence can be further used for the stress distribution evaluation. The change of magnetization direction in the material is obtained by varying the magnetic flux density in two perpendicular yokes of the apparatus. We present...
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Influence of plastic deformation on stray magnetic field distribution of soft magnetic steel sample
PublikacjaThe effect of various combinations of conditions, i.e., presence of the Earth’s magnetic field during and after deformation on the distribution of stray magnetic field of S355 steel sample, which is locally deformed, was investigated. Some of the stages of the experiment were carried out in zero magnetic field. Compensation of the Earth’s magnetic field was obtained by the application of a pair of Helmholtz coils. These coils are...
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Estimation of the effectiveness of nbpt for limiting ammonia emission from urea based on the field experiments
PublikacjaThe efectiveness of the ammonia emission reduction from NBPT-stabilized urea was investigating in 2011 during a field experiment on a grassland plot fertilized with a one-time dose of 60 kgN/ha. The obtained reduction coefficient of ammonia emission equaled 73% and 39-51% relative to erea without the inhibitor and ammonium nitrate, respectively.
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Extraction of antenna pattern from near field antenna measurements distorted by undesired emission
PublikacjaIn this paper authors present experimental correction of antenna pattern obtained from near field measurements when they are distorted by determined electromagnetic emission. Such situation may be met e.g. when feeding or supply subsystem interacts with antenna radiation pattern due to self-emission. Presented results of experiments show effectiveness of extraction of antenna pattern utilizing near field antenna measurements.
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Low Field NMR Studies of Wheat Bread Enriched with Potato Juice During Staling
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Phylogenetic and geographic analysis of fowl adenovirus field strains isolated from poultry in Poland
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Dielectric response of electric-field distortions of the twist-bend nematic phase for LC dimers
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Effect of GO-Fe3O4 and rotating magnetic field on cellular metabolic activity of mammalian cells
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Magnetic field effects in dye-sensitized solar cells controlled by different cell architecture
PublikacjaThe charge recombination and exciton dissociation are generally recognized as the basic electronic processes limiting the efficiency of photovoltaic devices. In this work, we propose a detailed mechanism of photocurrent generation in dye-sensitized solar cells (DSSCs) examined by magnetic field effect (MFE) technique. Here we demonstrate that the magnitude of the MFE on photocurrent in DSSCs can be controlled by the radius and...
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Scattering From a Cylindrical Object of Arbitrary Cross Section With the Use of Field Matching Method
PublikacjaA simple and intuitive solution to scattering problems in shielded and open structures is presented. The main idea of the analysis is based on the direct field matching technique involving the usage of projection of the fields at the boundary on a fixed set of orthogonal basis functions. Different convex shapes and various obstacle materials are considered to verify the validity of the method in open and closed structures. The...
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Sensorless Field Oriented Control of Five Phase Induction Motor with Third Harmonic Injection
PublikacjaIn this paper, a sensorless field oriented control system of five-phase induction machine with the 3rd harmonic rotor flux is presented. Two vector models, α1-β1 and α3-β3, were transformed into d1-q1, d3-q3 models oriented in rotating frames, which correspond to the 1st and 3rd harmonic plane respectively. The authors proposed the linearization of the model in d-q coordinate frames by introducing a new variable “x” which is proportional...
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Determination of odour concentration by TD-GC×GC–TOF-MS and field olfactometry techniques
PublikacjaField olfactometry is one of the sensory techniques used to determine odour concentration, in atmospheric air, directly in emission sources. A two-dimensional gas chromatography with time of flight mass spectrometer (GC×GC–TOF-MS) allows performing the chemical characterization of various groups of chemical compounds, even in complex mixtures. Application of these techniques enabled determination of odour concentration level in...
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Resonance microstrip structure with patch of arbitrary convex geometry with the use of field matching technique
PublikacjaAn analysis of the resonance frequency problem of planar microstrip structure with patch of arbitrary convex geometry is presented. A full-wave analysis is employed utilizing a combination of Galerkin’s moment method and field matching technique. In this approach, a field matching technique is adopted to calculate the patch surface current densities, and next the method of moments is utilized to calculate resonance frequencies...
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Field tests on hydrodynamic and hybrid operation of a bi-directional thrust bearing of a pump-turbine
PublikacjaIn vertical shaft pump turbines operating in pumped storage power plants an important role is played by a thrust bearing. Because of bi-directional character of operation, thrust bearing tilting pads have to be supported symmetrically, which is known to be unfavourable from the point of view of their performance. Large thrust bearings have to be carefully designed so as to minimise excessive thermo-elastic pad deformations. The...
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A Low-Cost System for Far-Field Non-Anechoic Measurements of Antenna Performance Figures
PublikacjaPrototype measurements are the key step in the development of antenna structures. Typically, their far-field characteristics are validated in expensive, dedicated facilities such as open range sites, or anechoic chambers. Despite being necessary for obtaining high-precision data (e.g., for device qualification), the use of costly infrastructure might not be fully justified when the main goal of measurements includes demonstration...
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Dynamic fracture of brittle shells in a space-time adaptive isogeometric phase field framework
PublikacjaPhase field models for fracture prediction gained popularity as the formulation does not require the specification of ad-hoc criteria and no discontinuities are inserted in the body. This work focuses on dynamic crack evolution of brittle shell structures considering large deformations. The energy contributions from in-plane and out-of-plane deformations are separately split into tensile and compressive components and the resulting...
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Experimental and theoretical investigation into pressure field in a shroud clearance. Part I: Experimental research
PublikacjaPrzedstawiono wyniki badań eksperymentalnych rozkładu ciśnienia w uszczelnieniu nadbandażowym stopnia powietrznej turbiny modelowej. Badania przeprowadzono dla różnej częstości obrotowej wirnika i różnego obciążenia turbiny. Wyniki porównano z rezultatami obliczeń teoretycznych w II części artykułu.
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A field programmable analog array for CMOS continuous-time OTA-C filter applications
PublikacjaW artykule opisano programowalny wzmacniacz transkonduktancyjny oraz konfigurowalny blok analogowy CAB składający się ze wzmacniacza transkonduktancyjnego, kluczy oraz programowalnego kondensatora. Z bloków CAB można zbudować uniwersalne, programowalne filtry. Wzmacniacz transkondukancyjny został przesymulowany oraz wykonany w technologii CMOS. Wyniki pomiarów pokazują, że transkonduktancja wzmacniacza może być przestrajana ponad...
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Design of hight voltage busbar: trade off between electrical field and stray inductance
PublikacjaArtykuł dotyczy optymalizacji konstrukcji i technologii szyny doprowadzenia zasilania do pojedynczej gałęzi falownika średniego napięcia. Dla szeregowego układu złożonego z trzech modułów elektroizolowanych (6 par tranzystorów i diod) rozważono warianty geometrii szyny zasilania przy uwzględnieniu wypadkowej indukcyjności obwodu komutacyjnego. Wyznaczono główne składniki indukcyjności rozproszenia oraz wykazano jej wpływ na przepięcia...
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Optimizing acoustic field intesity algorithms using the sound ray surface density method.
PublikacjaW artykule przedstawiono zagadnienia optymalizacji algorytmów komputerowych obliczeń rozkładów natężeń pola akustycznego w akwenie w zależności od za- mierzonych warunków hydrologicznych pod kątem skrócenia czasu obliczń.
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A new time-frequency detection method of stray current field interferenceon metal structures.
PublikacjaA new detection method has been presented of stray current field interference on underground metal structures. The method employs short time Fourier transformation (STFT). This method of analysis allows determination of signal spectral power density changes (e.g., structure potential) in the function of time. In the paper results have been presented of total time–frequency analysis of a pipeline potential in a stray current field...
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Development of globalization in culture on the example of Europe
PublikacjaThis article attempts to reflect on the consequences of cultural globalization i.e. the opporturnities and threats that exist it brings with it for existing local cultures. As we know, The processes of globalization contribute to the emergence of any, often contradictory phenomena in the field of culture which influence the existing local cultural systems in various ways. It is assumed that the most important consequence of cultural...
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generation of the vorticity mode by sound in a bingham plastic
PublikacjaThis study investigates interaction between acoustic and non-acoustic modes, such as vorticity mode,in some class of a non-newtonian fluid called Bingham plastic. The instantaneous equations describinginteraction between different modes are derived. The attention is paid to the nonlinear effects in the fieldof intense sound. The resulting equations which describe dynamics of both sound and the vorticity modeapply to both periodic...
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Observations of presumable groundwater seepage occurrence in Puck Bay (the Baltic Sea)
PublikacjaWe report the results of recent field measurements of seawater thermohaline structure and transparency carried out in early summer 2014 in Puck Bay. Near-bottom, less saline waters occurred almost in the entire study area. Their occurrence in the shallow part of Puck Bay was accompanied by an increase in the seawater transparency. The most likely explanation of these observations is a submarine fresh groundwater discharge.