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Wyniki wyszukiwania dla: VIBRATION CORRELATION TECHNIQUE
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Respiratory system modelling and simulation basing on the forced oscilation technique
PublikacjaConventional methods of testing lung functioning demand a specific respiratory action of the patient. In contrast, the forced oscillation technique (fot) provides measurements obtained with a minimal cooperation of the subject. The aim of this study is to verify the usefulness of the forced oscillation technique modelling in respiratory system diagnosing. in order to do it two models of fot measurements have been considered: the...
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Correlation between Fractal Dimension and Areal Surface Parameters for Fracture Analysis after Bending-Torsion Fatigue
PublikacjaThis paper investigates the fracture surface topography of two steel and aluminum alloys subject to bending-torsion fatigue loadings, as well as their susceptibility to fatigue performance and failure mechanisms. Using fracture surface topography data analysis, elements with different geometries were elaborated. A correlation between the fractal dimension, other selected parameters of surface topography such as areal Sx, and...
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Sensitivity study of correlation for flow boiling in tubes.
PublikacjaW referacie skupiono uwagę na szczegółowym zbadaniu wpływu wybranych typów modeli, opisujących współczynnik oporu przepływu oraz współczynnik przejmowania ciepła dla wrzenia w przepływie na korelację dla wrzenia w przepływie ( wyprowadzoną dla rur o konwencjonalnych wymiarach -półempiryczny model Mikielewicza ). Otrzymane wyniki porównano z danymi eksperymentalnymi.
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Correlation between shape errors in flat grinding
PublikacjaW pracy przedstawiono wyniki badań eksperymentalnych i symulacyjnych związanych z wpływem błędów kształtu narzędzia na błędy ksztaltu przedmiotu szlifowanego w układzie docierarki jednotarczowej. Szlifowanie realizowane było z wykorzystaniem specjalnych narzędzi z możliwością regulacji przekroju promieniowego.
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Multiple-Input Multiple-Output Technique for Underwater Acoustic Communication System
PublikacjaThe performance of an underwater acoustic communication (UAC) system is limited due to tough propagation conditions in the UAC channel. Multiple-Input Multiple-Output (MIMO) technique can improve the reliability of the data transmission system, increase its speed, increase its range, and reduce the energy consumption. The paper presents an implementation method of MIMO technique in the form of coding the Space-Time Block Code and...
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An in situ technique for the assessment of adhesive properties of a joint under load
PublikacjaSlow crack propagation in adhesive bonded joints has been characterised using an asymmetric wedge test. Crack position was evaluated from strain gauge measurements, both in the debonded partof the joint and in the bonded zone. Test temperature was changed during loading, giving insight into bond evolution. The technique allows accurate, and virtually continuous, determination of crack position to be made, and therefore the evaluation...
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Application of OFDM technique to underwater acoustic data transmission
PublikacjaPerformances of underwater acoustic communication (UAC) digital systems are strongly related to specific transmission properties of the underwater channel. Depending on the characteristics of the channel, an architecture and modulation techniques are usually implemented that are known as reliable solutions for data transmission in difficult radio channels. The OFDM technique seems to be the most promising nowadays. The parameters...
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Coacervative extraction as a green technique for sample preparation for the analysis of organic compounds
PublikacjaOne of the present trends in analytical chemistry is miniaturization, which is one of the methods of green analytical chemistry application. A particular emphasis is placed on the elimination of the use of large amounts of organic solvents which are toxic and harmful to the environment, maintaining high efficiency of the extraction process, high recovery values and low values of quantification (LOQ) and detection (LOD) limits....
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A Novel Synthesis Technique for Microwave Bandpass Filters with Frequency-Dependent Couplings
PublikacjaThis paper presents a novel synthesis technique for microwave bandpass filters with frequency-dependent couplings. The proposed method is based on the systematic extraction of a dispersive coupling coefficient using an optimization technique based on the zeros and poles of scattering parameters representing two coupled resonators.The application of this method of synthesis is illustrated using two examples involving four and five-pole...
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The potential of LC–MS technique in direct analysis of perfume content
PublikacjaPerfumes are products that consist of a wide range of natural and synthetic compounds. Due to complex composition, the determination of their ingredients is a difficult task. Most of the perfume components are either volatile or semi-volatile; however, most of the attention has been paid to volatile ones, and thus, gas chromatography or electronic noses are generally used. Nevertheless, in this study, liquid chromatography coupled...
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Vibration surveillance of dynamic systems and production processes
PublikacjaPraca dotyczy poszukiwania sposobów minimalizacji poziomu drgań podczas pracy maszyn i urządzeń wykonujących określone procesy robocze. Do modelowania dyskretnego wykorzystano metodę elementów skończonych. Rozważano dynamikę niestacjonarnego dyskretnego układu sterowanego, którego zachowanie opisano we współrzędnych uogólnionych, jak również - układu hybrydowego. Ten ostatni uzyskano dzięki wyodrębnieniu z całości podukładu stacjonarnego,...
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Failure characterisation of sandwich beams using integrated acoustic emission and digital image correlation techniques
PublikacjaThe paper presents the experimental study of the failure behaviour of sandwich beams subjected to bending. The samples examined are sandwich beams made of polyethylene terephthalate foam core and glass fibre-reinforced polymer laminate face sheets. In a series of experiments, it has been proposed to integrate diagnostic techniques with acoustic emission and digital image correlation to accurately track the cracking process on the...
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Sensitivity analysis of free torsional vibration frequencies of thin-walled laminated beams under axial load
PublikacjaThe paper addresses sensitivity analysis of free torsional vibration frequencies of thin-walled beams of bisymmetric open cross-section made of unidirectional fibre-reinforced laminate. The warping effect and the axial end load are taken into account. The consideration is based upon the classical theory of thin-walled beams of non-deformable cross-section. The first-order sensitivity variation of the frequencies is derived with...
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Control of the bridge span vibration with high coefficient passive damper. Theoretical consideration and application
PublikacjaThe research was carried out due to the problem of vibration on the lively pedestrian drawbridge across the Motlawa River in the city of Gdansk. In the design stage, the main span of the footbridge showed unfavorable dynamic properties, which may create a comfort problem for pedestrians. The first vertical bending eigenfrequency was recognized as 1.64 Hz. The original design of the footbridge was equipped with a driving cylinder...
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Correlation–polarization effects in electron/positron scattering from acetylene: A comparison of computational models
PublikacjaDifferent computational methods are employed to evaluate elastic (rotationally summed) integral and differential cross sections for low energy (below about 10 eV) positron scattering off gas-phase C2H2 molecules. The computations are carried out at the static and static-plus-polarization levels for describing the interaction forces and the correlation–polarization contributions are found to be an essential component for the correct...
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Real-Time PCR: molecular technique of many applications
PublikacjaReal-Time PCR is a sensitive DNA amplification technique initially applied in genetics and molecular biology. It enables in vivo copying of the selected DNA fragment (flanked by two primers) by the thermostable polymerase (in the presence of magnesium ions and deoxynucleotide triphosphates) and simultaneous measurement of the fluorescence. For one or more specific sequences in a DNA sample, real-time PCR enables both detection...
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A study of cavitation erosion resistance of an ion nitrided titanium alloy by means of the vibration and rotating disk methods
PublikacjaIn this work, a comparative analysis of the cavitation erosion resistance of the Ti– 6.7Al–2.5Mo–1.8Cr–0.5Fe–0.25Si alloy (known as brand VT3-1) before and after lowtemperature ion nitriding is carried out. Two test methods were applied, using vibrative (ASTM G-32) and rotating disk rigs, respectively. The kinetic dependences of the erosive destruction of samples of titanium alloy VT3-1 in the initial state, after ion nitriding...
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Correlation between Compressive Strength and Heat of Hydration of Cement Mortars with Siliceous Fly Ash
PublikacjaThis paper presents the results of calorimetric and strength tests of mortars with ordinary Portland cement and two substitution rates (10 and 20%) of cement by siliceous fly ash. The prepared samples were cured under isothermal conditions at four different temperatures: 23, 33, 43 and 53 °C. Heat of hydration was measured using an isothermal calorimeter dedicated to monitor the hydration process of cementitious composites such...
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A fast technique for diplexer design
Publikacjaw artykule zaprezentowano nową metodę projektowanie mikrofalowych diplekserów. metoda bazuje na dokładnej syntezie filtrów kanałowych wykorzystującej modele zastępcze współczynników sprzężeń w celu uzyskania wstępnych wartości wymiarów układu. następnie dokonywana jest pełnofalowa optymalizacja filtrów kanałowych. ostateczne strojenie numeryczne jest ograniczone do tylko jednego elementu.
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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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The Modifiable Areal Unit Problem – Analysis of Correlation and Regression
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Correlation between Length of Life and Exposure to Air Pollution
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Is the p-chloroaniline anion bound almost entirely by correlation?
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Analysis of correlation between heart rate and blood pressure
PublikacjaW artykule przedstawiono analizę korelacji pomiędzy częstością akcji serca (HR) i ciśnieniem krwi (BP). Wykorzystano rzeczywiste pomiary ciśnienia skurczowego i rozkurczowego krwi zmierzonego metodą inwazyjną w tętnicy promieniowej. Ze względu na możliwe zaszumienie sygnału przeanalizowano także dane po filtracji filttrem uśredniającycm oraz wykonano analizę trendów sygnałów. Wyniki analizy zarówno danych pomiarowych jak i filtrowanych...
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Airstrip Ground Improvement Works by Blasting Charge Technique and Dredged-Ash Material Mixture
PublikacjaSoil improvement by blasting charge technique is known in geotechnics as one of the efficient and inexpensive method. It can be used in preparing of underground to found road construction and buildings as well. The technique proves usefulness especially when dynamic load is applied. It is because of non-stiff or rather resilient type soil after improvement. In noncohesive or organic soil, blasting charge...
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Urban Mentoring as a new polish management technique in participatory planning
PublikacjaA decade of experience in implementation of numerous urban modernization projects in Poland resulted in a lively debate on socialization of the planning process, in which the matter of the public space quality has become the center of gravity. In those years, transformation from the classic administrative model of „bureaucracy planning” to the model of „management planning” has not been complete. The socialist primacy of the public...
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Recurrent potential pulse technique for improvement of glucose sensing ability of 3D polypyrrole
PublikacjaIn this work, a new approach for using a 3D polypyrrole (PPy) conducting polymer as a sensing material for glucose detection is proposed. Polypyrrole is electrochemically polymerized on a platinum screen-printed electrode in an aqueous solution of lithium perchlorate and pyrrole. PPy exhibits a high electroactive surface area and high electrochemical stability, which results in it having excellent electrocatalytic properties. The...
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Using Fast Frequency Hopping Technique to Improve Reliability of Underwater Communication System
PublikacjaAcoustic underwater communication systems designed to work reliably in shallow coastal waters must overcome major limitations such as multipath propagation and the Doppler effect. These restrictions are the reason for the complexity of receivers being built, whose task is to decode a symbol on the basis of the received signal. Additional complications are caused by the low propagation speed of the acoustic wave in the water and...
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Hybrid Technique for the EM Scattering Analysis with the Use of Ring Domain Decomposition
PublikacjaA hybrid technique combining finite-element and mode-matching methods for the analysis of scattering problems in open space is presented here. The main idea is based on impedance matrix descriptions of the boundary surrounding the discrete computational domain and combine it with external field described analytically. The discrete analysis, which is the most time- and memory-consuming, is limited here only to the close proximity...
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Scattering and Propagation Analysis for the Multilayered Structures Based on Field Matching Technique
PublikacjaA semi-analytical method is employed to the analysis of scattering and guiding problems in multilayer dielectric structures. The approach allows to investigate objects with arbitrary convex cross section and 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. For the scattering problems the scattered field in the far zone is calculated...
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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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An adaptation of modal control to vibration control of industrial robots
PublikacjaRozważania dotyczą drgań niestacjonarnego układu nośnego manipulatora IRb-6. Do nadzorowania drgań zastosowano algorytm sterowania modalnego przy energetycznym wskaźniku jakości. Celem proponowanego algorytmu jest minimalizacja poziomu drgań końcówki manipulatora, co spowoduje zwiększenie obciążeń dopuszczalnych współczesnych linii zrobotyzowanych, jak również poprawę dokładności oraz powtarzalności pozycjonowania robota.
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A mechatronic approach towards vibration surveillance of manipulator robots
PublikacjaW pracy przedstawiono nadzorowanie drgań niestacjonarnego układu nośnego manipulatora IRb-6 z wykorzystaniem sterowania modalnego przy energetycznym wskaźniku jakości. Celem proponowanego algorytmu jest minimalizacja poziomu drgań końcówki manipulatora, co prowadzi do zwiększenia dopuszczalnych obciążeń współczesnych linii zrobotyzowanych oraz do poprawy dokładności i powtarzalności pozycjonowania robota. Rozważania dotyczą zadanej...
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Optimum control of the selected vibration forms in mechanical systems
PublikacjaW artykule przedstawiono zagadnienie optymalnego sterowania wybranymi formami drgań układów mechanicznych. Dla zaprezentowania sposobu i procedury wyznaczania optymalnych nastaw regulatora i współczynników wagowych wskaźnika jakości posłużono się dwoma przykładami liczbowymi. W pierwszym z nich rozważano uproszczony układ mechaniczny składający się z dwóch sztywnych elementów skończonych połączonych za pomocą elementów sprężysto-tłumiących,...
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Active Damping of Impulse-Excited Flexible Plate Vibration
PublikacjaArtykuł prezentuje metodę aktywnego tłumienia drgań podatnej płytki wzbudzanych impulsowo. Układ sterowania składa się z aktywych wzbudników piezoelektrycznych przymocowanych do przedmiotu. Efektywnośc metody została potwierdzona badaniami eksperymentalnymi.
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Vibration transpotation of a viscoelastic raw materials in drying process.
PublikacjaPrzedstawiono zagadnienie transportu wibracyjnego surowca o własnościach lepko-sprężystych w procesie suszenia oraz propozycje rozwiązania technicznego umożliwiającego zastosowanie tego sposobu transportu w urządzeniach produkcyjnych. W rozwiązaniu tym zastosowano panele zawieszone na elementach sprężystych, których drgania sterowane są mikroprocesorowo w układzie sterowania w pętli sprzężenia zwrotnego w celu utrzymania właściwych...
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Vibration based damage localization in non-homogeneous structures
PublikacjaPrzedmiotem badań jest identyfikacja lokalnych uszkodzeń w konstrukcjach budowlanych. Przedstawione są trzy metody bazujące na teorii drgań. Są to metody badające: częstości własne, podatność i krzywizny postaci drgań układu. Skuteczność metod pokazana jest na przykładach symulacji komputerowych, wykonanych dla belki swobodnie podpartej, wspornikowej oraz podwieszonej kładki dla pieszych. Dodatkowo zaprezentowane są wyniki badań...
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Vibration monitoring of structures in the light of the Polish and international requirements
PublikacjaThe paper concerns the wide range of strategies used to protect structures against man-made dynamic excitation. The most popular approaches applied worldwide are compared, and the main differences and similarities are summarized. The literature studies are supported by the results of the measurements performed on different types of real structures, which are sensitive and insensitive to the dynamic load. To make the conclusions...
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Vibration and buckling characteristics of nonlocal beam placed in a magnetic field embedded in Winkler–Pasternak elastic foundation using a new refined beam theory: an analytical approach
PublikacjaIn this article, a new refined beam theory, namely one variable first-order shear deformation theory, has been employed to study the vibration and buckling characteristics of nonlocal beam. The beam is exposed to an axial magnetic field and embedded in Winkler–Pasternak foundation. The von Kármán hypothesis along with Hamilton’s principle has been implemented to derive the governing equations for both the vibration and buckling...
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Damped forced vibration analysis of single-walled carbon nanotubes resting on viscoelastic foundation in thermal environment using nonlocal strain gradient theory
PublikacjaIn this paper, the damped forced vibration of single-walled carbon nanotubes (SWCNTs) is analyzed using a new shear deformation beam theory. The SWCNTs are modeled as a flexible beam on the viscoelastic foundation embedded in the thermal environment and subjected to a transverse dynamic load. The equilibrium equations are formulated by the new shear deformation beam theory which is accompanied with higher-order nonlocal strain...
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Resonance Frequency Calculation of a Multilayer and Multipatch Spherical Microstrip Structure Using a Hybrid Technique
PublikacjaThis communication offers a rigorous analysis of the resonance frequency problem of a spherical microstrip structure mounted on a multilayer, dielectric-coated metallic sphere, with an electrically small radius. The structure consists of single or multiple metallic patches with arbitrary shapes. A full-wave analysis is employed with the use of proposed hybrid approach, combining the finite-difference technique with a spectral domain...
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The difficulties in polybrominated diphenyl ethers identification by GC-EI-MS technique
PublikacjaAwareness about the harmful effects of brominated flame retardants on living organisms increases mainly due to link their presence in the human environment with health disorders. Therefore is a need to conduct research aimed at content control of these chemicals in the environment. Recent improvements in injection techniques and mass spectrometer ionization methods have led to a variety of options to determine PBDEs in environmental...
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Application of soil nailing technique for protection and preservation historical buildings
PublikacjaSoil nailing is one of the recent in situ techniques used for soil improvement and in stabilizing slopes. The process of soil nailing consists of reinforcing the natural ground with relatively small steel bars or metal rods, grouted in the pre-drilled holes. This method has a wide range of applications for stabilizing deep excavations and steep slopes. Soil nailing has recently become a very common method of slope stabilisation...
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Computer simulation of vibration surveillance of discretely idealised mechanical systems. Part II: Tool-workpiece vibration in a non-stationary model of the cutting process
PublikacjaPrzedmiotem rozważań jest problem nadzorowania drgań narzędzie-przedmiot obrabiany w procesie skrawania. Dokonano analizy obiektu badań oraz dynamiki skrawania. Utworzono niestacjonarny model obliczeniowy. Przedstawiono różne podejścia oraz przykłady symulacji komputerowych nadzorowania drgań z wykorzystaniem modelu niestacjonarnego. Bazowały one na sterowaniu optymalnym oraz sterowaniu skokową zmiana prędkości obrotowej wrzeciona....
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EVALUATION OF LIQUID-GAS FLOW IN PIPELINE USING GAMMA-RAY ABSORPTION TECHNIQUE AND ADVANCED SIGNAL PROCESSING
PublikacjaLiquid-gas flows in pipelines appear in many industrial processes, e.g. in the nuclear, mining, and oil industry. The gamma-absorption technique is one of the methods that can be successfully applied to study such flows. This paper presents the use of thegamma-absorption method to determine the water-air flow parameters in a horizontal pipeline. Three flow types were studied in this work: plug, transitional plug-bubble,...
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Time Delay Estimation in Two-Phase Flow Investigation Using the γ-Ray Attenuation Technique.
PublikacjaTime delay estimation is an important research question having many applications in a range of technologies. Measurement of a two-phase flow in a pipeline or an open channel using radioisotopes is an example of such application. For instance, the determination of velocity of dispersed phase in that case is based on estimation of the time delay between two stochastic signals provided by scintillation probes. The proper analysis...
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Correlation between chemical composition and the presence of selected groups of bacteria in freshwater samples collected from Isfjorden and Billefjorde
PublikacjaThe average concentrations of pollutants in the arctic water, snow and the atmosphere are much lower than those observed in the temperate climate. Specific conditions occurring in the polar regions have apotential to accumulate the pollutants transported from other parts of the world. In this study, attempts were made to find a correlation between selected chemical components and the bacterial population. The analysis involved...
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Characterization of home-made and regional fruit wines by evaluation of correlation between selected chemical parameters
PublikacjaSince the last decade of the 20th century, there has been rising interest in the production of fruit wines, as evidenced by the high number of published papers and books covering this matter. When aiming to produce quality fruit wines, it is essential to evaluate the analytical parameters of the beverage. In this context, there are a large number of analyses for the evaluation of wines and fruit wines. This article characterizes...
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Application of the fluid–structure interaction technique for the analysis of hydrodynamic lubrication problems.
PublikacjaFluid–structure interaction technique seems to be one of the most promising possibilities for theoretical analysis of lubrication problems. It allows coupling of different physical fields in one computational task, taking into account the interaction between them. In this article, two sets of fluid–structure interaction analyses focusing on the bearing performance evaluation are presented. One analysis was applied to a water-lubricated...
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Signal Reconstruction from Sparse Measurements Using Compressive Sensing Technique
PublikacjaThe paper presents the possibility of applying a new class ofmathematical methods, known as Compressive Sensing (CS) for recovering thesignal from a small set of measured samples. CS allows the faithful recon-struction of the original signal back from fewer random measurements bymaking use of some non-linear reconstruction techniques. Since of all thesefeatures, CSfinds its applications especially in the areas where, sensing is...