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Representation of magnetic hysteresis in single-phase transformer for circuit simulations
PublikacjaThe paper presents a mathematical model for the hysteresis phenomenon in a multi-winding single-phase core type transformer. In the circuit transformer model, it is assumed that there is a flux common Φ to all windings as nonlinear and hysteretic function of the total currents Θ (Ampere turns) of all windings. To simulate magnetic behaviour of the iron core the feedback scalar Preisach model of hysteresis is developed. The Preisach...
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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.
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New potential functions for greedy independence and coloring
PublikacjaA potential function $f_G$ of a finite, simple and undirected graph $G=(V,E)$ is an arbitrary function $f_G : V(G) \rightarrow \mathbb{N}_0$ that assigns a nonnegative integer to every vertex of a graph $G$. In this paper we define the iterative process of computing the step potential function $q_G$ such that $q_G(v)\leq d_G(v)$ for all $v\in V(G)$. We use this function in the development of new Caro-Wei-type and Brooks-type...
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On the Nonlinear Effects of Magnetoacoustic Perturbations in a Perfectly Conducting Viscous and Thermoconducting Gas
PublikacjaNonlinear effects of planar and quasi-planar magnetosound perturbations are discussed. The plasma is as- sumed to be a Newtonian thermoconducting gas with infinite electrical conductivity permeated by a magnetic field orthogonal to the trajectories of gas particles. Generation of the non-wave modes (magnetoacoustic heating and streaming) in the field of periodic and aperiodic magnetoacoustic perturbations is discussed. The results...
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Airborne and mobile laser scanning in measurements of sea cliffs on the southern Baltic
PublikacjaMeasurements of sea cliffs performed using periodic surveying based on laser scanning is currently one of the fastest and most accurate solutions. Supported with the technology of satellite measurements using GNSS (Global Navigation Satellite System) positioning and photographic measurements with the use of aerial vehicle, they enable an effective monitoring of the sea cliffs affected by the erosion. In case of the coast of southern...
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Generalized adaptive comb filters/smoothers and their application to the identification of quasi-periodically varying systems and signals
PublikacjaThe problem of both causal and noncausal identification of linear stochastic systems with quasiharmonically varying parameters is considered. The quasi-harmonic description allows one to model nonsinusoidal quasi-periodic parameter changes. The proposed identification algorithms are called generalized adaptive comb filters/smoothers because in the special signal case they reduce down to adaptive comb algorithms used to enhance...
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Substrate-integrated waveguide (SIW) filter design using space mapping
PublikacjaIn this paper, we present a fast technique for an automated design of microwave filters in substrate integrated wave (SIW) technology. The proposed methodology combines the space mapping technique with a cost function defined using the location of complex zeros and poles of filter’s transfer and reflection function and uses a rectangular waveguide as a surrogate model. The effectiveness of the proposed technique is presented with...
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Quality of limes juices based on the aroma and antioxidant properties
PublikacjaKaffir (Citrus hystrix) and Key (Citrus aurantifolia) limes juices were investigated and compared. Two dimensional gas chromatography coupled with time-of-flight mass spectrometry (GC×GC-TOF-MS) was applied to assess the botanical origin of Kaffir and Key limes juices, based on volatile substances. The biggest differences in the contents of selected terpenes in Kaffir and Key limes occur in chemical compounds such as Limonene,...
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Secure Italian domination in graphs
PublikacjaAn Italian dominating function (IDF) on a graph G is a function f:V(G)→{0,1,2} such that for every vertex v with f(v)=0, the total weight of f assigned to the neighbours of v is at least two, i.e., ∑u∈NG(v)f(u)≥2. For any function f:V(G)→{0,1,2} and any pair of adjacent vertices with f(v)=0 and u with f(u)>0, the function fu→v is defined by fu→v(v)=1, fu→v(u)=f(u)−1 and fu→v(x)=f(x) whenever x∈V(G)∖{u,v}. A secure Italian dominating...
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Multimodal Genetic Algorithm with Phase Analysis to Solve Complex Equations of Electromagnetic Analysis
PublikacjaIn this contribution, a new genetic-algorithm-based method of finding roots and poles of a complex function of a complex variable is presented. The algorithm employs the phase analysis of the function to explore the complex plane with the use of the genetic algorithm. Hence, the candidate regions of root and pole occurrences are selected and verified with the use of discrete Cauchy's argument principle. The algorithm is evaluated...
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Modeling variable curvature on the turnout diverging track length
PublikacjaThe paper presents three variants of variable curvature application on the entire length of the turnout diverging track. One linear and two nonlinear curvature cases: described the function of C1 and C0 class were considered. It turned out that both linear curve and the function of C1 class requires a significant (even twice) length of diverging track extending with respect to the base turnout. The curvature described by the function...
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Scientific Collaboration, Citation and Topic Analysis of International Conference on Agile Software Development Papers
PublikacjaThe International Conference on Agile Software Development (XP) was established almost sixteen years ago. Based on data from Scopus database, a total of 789 papers have been published in between years of 2002 and 2018. We employed bibliometrics analysis and topic modeling with R/RStudio to analyze these published papers from various dimensions, including the most active authors, collaboration of authorship, most cited papers, used...
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Efficiency of acoustic heating in the Maxwell fluid
PublikacjaThe nonlinear effects of sound in a fluid describing by the Maxwell model of the viscous stress tensor is the subject of investigation. Among other, viscoelastic biological media belong to this non-newtonian type of fluids. Generation of heating of the medium caused by nonlinear transfer of acoustic energy, is discussed in details. The governing equation of acoustic heating is derived by means of the special linear combination...
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A variational approach of homogenization of piezoelectric composites towards piezoelectric and flexoelectric effective media
PublikacjaThe effective piezoelectric properties of heterogeneous materials are evaluated in the context of periodic homogenization, whereby a variational formulation is developed, articulated with the extended Hill macrohomogeneity condition. The entire set of homogenized piezoelectric moduli is obtained as the volumetric averages of the microscopic properties of the individual constituents weighted by the displacement and polarization...
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Efficiency of acoustic heating in the Maxwell fluid
PublikacjaThe nonlinear effects of sound in a fluid describing by the Maxwell model of the viscous stress tensor is the subject of investigation. Among other, viscoelastic biological media belong to this non-newtonian type of fluids. Generation of heating of the medium caused by nonlinear transfer of acoustic energy, is discussed in details. The governing equation of acoustic heating is derived by means of the special linear combination...
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Connecting orbits for a periodically forced singular planar Newtonian system
PublikacjaW niniejszym artykule badamy problem istnienia i krotności rozwiązań homoklinicznych i heteroklinicznych dla nieautonomicznych układów Newtonowskich na płaszczyźnie z potencjałem okresowym ze względu na zmienną czasową, mającym maksimum globalne właściwe przyjmowane w dwóch punktach płaszczyzny i punkt osobliwy (studnię nieskończonej głębokości), w otoczeniu którego potencjał spełnia warunek Gordona (gradient potencjału ze względu...
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Gender, education and motivation of onwers of small firms and their growth
PublikacjaAlmost every article on the growht of SMEs begins with noting the lack of a unified theory or a model of growth in thei group of companies, although the growth of small and medium sized enterprises has been the subject of research for many years and early theories about it appeared already before the Second World War. In the paper some conlusions about the relation between gender, education and motivation of owner and the small...
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Measures of region failure survivability for wireless mesh networks
PublikacjaWireless mesh networks (WMNs) are considered as a promising alternative to wired local, or metropolitan area networks. However, owing to their exposure to various disruptive events, including natural disasters, or human threats, many WMN network elements located close to the failure epicentre are frequently in danger of a simultaneous failure, referred to as a region failure. Therefore, network survivability, being the ability...
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Termination functions for evolutionary path planning algorithm
PublikacjaIn this paper a study of termination functions (stop criterion) for evolutionary path planning algorithm is presented. Tested algorithm is used to determine close to optimal ship paths in collision avoidance situation. For this purpose a path planning problem is defined. A specific structure of the individual path and fitness function is presented. For the simulation purposes a close to real tested environment is created. Five...
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Investigation of Liquid–Gas Flow in a Horizontal Pipeline Using Gamma-Ray Technique and Modified Cross-Correlation
PublikacjaThis article presents the application of the radioisotope absorption method in the study of two-phase water–air flow in a horizontal pipe. The measurement principle and the test stand are briefly described. The main part of the article presents the signal analysis methods applied to data obtained from scintillation detectors. Because these signals are mostly stochastic waveforms, they were analyzed statistically using the cross-correlation...
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Representation of magnetic hysteresis in a circuit model of a single-phase transformer
PublikacjaThe 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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On Surface Kinetic Constitutive Relations
PublikacjaIn the framework of the strain gradient surface elasticity we discuss a consistent form of surface kinetic energy. This kinetic constitutive equation completes the statement of initial–boundary value problems. The proposed surface kinetic energy density is the most general function consistent with the constitutive relations in bulk. As the surface strain energy depends on the surface deformation gradient and its gradient, the kinetic...
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Virtual reality as a tool for development and simulation. Research projects and experience of the Gdańsk University of Technology
PublikacjaBy supporting the human imagination, virtual reality technology can be applied in almost every human activity. This is evidenced by the cooperation of the Immersive 3D Visualization Lab with specialists representing such different professions from architects and artists, astronomers and chemists, through historians and museologists, criminologists and military educators, mechanical and ship engineers, up to physicians and psychologists....
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Blood equivalent phantom vs whole human blood, a comparative study
PublikacjaPreclinical research of biomedical optoelectronic devices is often performed with the use of blood phantoms — a simpli¯ed physical model of blood. The aim of this study is the comparison and distinction between blood phantoms as well as whole human blood measurements. We show how the use of such phantoms may in°uence the incorrect interpretation of measured signal. On the other hand, we highlight how the use of blood phantoms enables...
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Wykładnicze równanie Arrheniusa jako funkcja dojrzałości twardniejącego betonu
PublikacjaPoprawne określenie funkcji dojrzałości dla mieszanki betonowej warunkuje powodzenie szacowania wytrzymałości na ściskanie na bazie pomiarów temperatury in situ. W artykule omówiono zastosowanie równania Arrheniusa do opisu funkcji dojrzewania twardniejącego betonu. Szczególną uwagę zwrócono na zależności szybkości zachodzenia reakcji w odmiennych warunkach temperaturowych. Przedstawiono wyniki własnych badań na kostkach zaprawy...
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Adaptive CAD-Model Construction Schemes
PublikacjaTwo advanced surrogate model construction techniques are discussed in this paper. The models employ radial basis function (RBF)interpolation scheme or artificial neural networks (ANN) with a new training algorithm. Adaptive sampling technique is applied withrespect to all variables. Histograms showing the quality of the models are presented. While the quality of RBF models is satisfactory, theperformance of the ANN models obtained...
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Density smoothness estimation problem using a wavelet approach
PublikacjaIn this paper we consider a smoothness parameter estimation problem for a density function. The smoothness parameter of a function is defined in terms of Besov spaces. This paper is an extension of recent results (K. Dziedziul, M. Kucharska, B. Wolnik, Estimation of the smoothness parameter ). The construction of the estimator is based on wavelets coefficients. Although we believe that the effective estimation of the smoothness...
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Stability by linear approximation for time scale dynamical systems
PublikacjaWe study systems on time scales that are generalizations of classical differential or difference equations and appear in numerical methods. In this paper we consider linear systems and their small nonlinear perturbations. In terms of time scales and of eigenvalues of matrices we formulate conditions, sufficient for stability by linear approximation. For non-periodic time scales we use techniques of central upper Lyapunov exponents...
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Interaction of Acoustic and Thermal Modes in the Vibrationally Relaxing Gases. Acoustic Cooling
PublikacjaThe dynamic equation which governs an excess temperature associated with the thermal mode in vibrationally relaxing gas is derived. The nonlinear transfer of acoustic energy to the energy of the thermal mode in a relaxing gas causes slow variation of temperature with time. The nal dynamic equation is instantaneous. All types of sound, including aperiodic, may be considered as an acoustic source of corresponding heating or cooling....
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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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The Unfolded Protein Response: A Double-Edged Sword for Brain Health
PublikacjaEfficient brain function requires as much as 20% of the total oxygen intake to support normal neuronal cell function. This level of oxygen usage, however, leads to the generation of free radicals, and thus can lead to oxidative stress and potentially to age-related cognitive decay and even neurodegenerative diseases. The regulation of this system requires a complex monitoring network to maintain proper oxygen homeostasis. Furthermore,...
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Technical Limitations in Merging Secular and Sacred Functions in Monumental Churches
PublikacjaThe abandonment of churches and their adaptation for secular purposes is a current subject in Europe and worldwide. Most cases involve objects that were desacralized and then rebuilt as a whole object for alternative functions. Thus far, the merging of secular and sacred functions in one monumental Catholic church has not raised any issues. The paper describes the case of St. Catherine’s Church in Gdansk, Poland, where sacred function...
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An assessment of Islamic banking in Bosnia and Herzegovina – a comparative analysis using the CAMELS approach
PublikacjaThis paper examines the phenomenon of Islamic banking in Bosnia and Herzegovina. Although almost half of the Bosnian population is recognized as Islamic, there is only one bank purely based on Sharia operating in this country. The aim of the article is to conduct a comparative analysis of the financial standing of this bank and the banking sector in this country and region. The chosen method of analysis is CAMELS which examines...
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Multi-Option Model of Railway Traffic Organization Including the Energy Recuperation
PublikacjaThe article presents the issue of organization of railway traffic within the station, taking into account energy recuperation. We identified a number of factors which affect the energy efficiency of recuperation, including the issue of transfer of energy technology between a few vehicles. We presented some aspects of the decision problem of graphic train timetable construction with regard to recuperation. As an indicator of quality...
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Zero-Pole Space Mapping for CAD of Filters
PublikacjaIn this paper, we propose a new space-mapping technique tailored to the CAD of microwave filters. The goal of space mapping is to achieve a satisfactory design with the minimal number of fine model evaluations. In our approach, the filter is represented by a rational function. To quickly align the coarse and fine models, and to speed up the direct optimization of the coarse model, we propose matching the zeros and poles of a rational...
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Możliwość oszacowania niezawodności silników o zapłonie samoczynnym z zastosowaniem teorii procesów semi-Markowa oraz podejmowania decyzji eksploatacyjnych z uwzględnieniem wiarygodności diagnozy o stanie technicznym tego rodzaju silników spalinowych = Possibility of estimating the reliability of diesel engines by applying the theory of semi-Markov processes and making operational decisions by considering reliability of diagnosis on technical state of this sort of combustion engines/
PublikacjaThe paper presents semi-Markov models of technical state transitions for diesel engines, useful for determining reliability of the engines. A possibility of application of a three-state model with a simplified matrix function, or even a two-state model, to determine reliability of the engines, has been described herein on examples of known from literature semi-Markov models, for the case when appropriate diagnosing systems (SDG)...
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Reduction of Computational Complexity in Simulations of the Flow Process in Transmission Pipelines
PublikacjaThe paper addresses the problem of computational efficiency of the pipe-flow model used in leak detection and identification systems. Analysis of the model brings attention to its specific structure, where all matrices are sparse. With certain rearrangements, the model can be reduced to a set of equations with tridiagonal matrices. Such equations can be solved using the Thomas algorithm. This method provides almost the same values...
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Testing Stability of Digital Filters Using Multimodal Particle Swarm Optimization with Phase Analysis
PublikacjaIn 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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Modelling of Mechanical Behaviour of High-Frequency Piezoelectric Actuators Using Bouc-Wen Model
PublikacjaThe paper presents the application of a modified, symmetrical Bouc-Wen model to simulate a mechanical behaviour of high-frequency piezoelectric actuators (PAs). In order to identify parameters of the model, a two-step algorithm was utilized. In the first stage, the mechanical parameters were identified by taking into account their bilinear variability and using a square input voltage waveform. In the second step, the hysteresis...
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Plasticity of Bead-On-Plate Welds Made with the Use of Stored Flux-Cored Wires for Offshore Applications
PublikacjaExtreme atmospheric conditions in the marine and offshore industry are harmful to engineering materials, especially to welded joints, and may cause degradation of their properties. This article presents the results of research on the plasticity of bead-on-plate welds made using two types of seamless, copper plated flux-cored wires. Before welding, spools with wire were stored for 1 month in two distinct locations with different...
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Influence of water and mineral oil on the leaks in satellite motor commutation unit clearances
PublikacjaThe article describes the flow rates of mineral oil and water flowing, as working media, through the commutation unit of a hydraulic satellite motor. It is demonstrated that geometrical dimensions of commutation unit clearances change as a function of the machine shaft rotation angle. Methods for measuring the rate of this flow and the pressure in the working chamber are presented. The results of pressure measurements in the working...
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Determination of the Theoretical and Actual Working Volume of a Hydraulic Motor—Part II (The Method Based on the Characteristics of Effective Absorbency of the Motor)
Publikacja: In this article, the second method of determination of the theoretical and actual working volume of a hydraulic motor is described. The proposed new method is based on the characteristics of effective absorbency of the motor. The effective absorbency has been defined as the ratio of flow rate in a motor to the rotational speed of the motor’s shaft. It has been shown that the effective absorbency is a nonlinear function of the...
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Port-Based Modelling of Distributed-Lumped Parameter Systems
PublikacjaThere in the paper is presented an uniform, port-based approach to modelling of both lumped and distributed parameter systems. Port-based model of the distributed system has been defined by application of bond graph methodology and distributed transfer function method (DTFM). The approach proposed combines versatility of port-based modelling and accuracy of distributed transfer function method. The concise representation of lumped-distributed...
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Effectiveness of the robust PSS design
PublikacjaThe paper discusses optimal PSS of synchronous generator synthesis. The optimal controller is an Hinf controller, what means that minimises Hinf norm of transfer function between the exogenous signals such as reference inputs and disturbances, and the error signals which are to be minimised to meet the control objective. The dynamic properties of the plant are shaped by choosing appropriate weighting function applied to the plant...
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Reliability Analysis of Data Storage Using Survival Signature and Logic Differential Calculus
PublikacjaThe Data storage system is an important part of any information system. All the necessary data that must be available for the successful operation of the information system are stored here. Therefore, it is advisable to think about the reliability of such a data storage system. As part of reliability engineering, it is possible to perform a reliability analysis of any system. Therefore, the data storage system can be analyzed as...
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The changes of groundwater quality of the ''Czarny Dwór'' intake as a result of the aquifer vulnerability
PublikacjaThe "Czarny Dwór" groundwater intake is one of the main sources of water for Gdańsk. It is situated on the Marine Terrace and exploits mainly Quaternary aquifer, but also Tertiary and Cretaceous. The water is generally of good quality although some undesirable changes were observed in the Quaternary aquifer during almost 40 years of exploitation. The changes are caused by developing urbanization, former high pumping rates and...
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Electoral support for extreme right-wing parties: A sub-national analysis of western European elections
PublikacjaThis paper addresses two major limitations of cross-national research on electoral support for extreme right parties (ERPs) in western Europe: its almost exclusive focus on national-level data and its failure to examine the role of the social welfare state and social capital. We employ Tobit I estimations in an additive and interactive model and compute conditional coefficients and standard errors for several interactive variables....
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The finite difference methods of computation of X-rays propagation through a system of many lenses
PublikacjaThe propagation of X-ray waves through an optical system consisting of many beryllium X-ray refrac- tive lenses is considered. In order to calculate the propagation of electromagnetic in the optical sys- tem, two differential equations are considered. First equation for an electric field of a monochromatic wave and the second equation derived for complex phase of the same electric The propagation of X-ray waves through an optical system...
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Structure of liquid gold from tight-binding driven molecular-dynamics
PublikacjaPraca przedstawia wyniki symulacji ciekłego złota w nadkomórce periodycznej przy użyciu stworzonego przez autorów programu komputerowego, za pomocą połączonych metod dynamiki molekularnej (MD) i ciasnego wiązania (TB). Omówiono strukturę tak symulowanej cieczy, porównując ją z dostępnymi danymi doświadczalnymi oraz wynikami innych symulacji, pod kątem radialnej i kątowej funkcji rozkładu i elektronowej gęstości stanów.A tight-binding...
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Taguchi sensors under temperature modulation
PublikacjaSemiconductor gas sensors are widely used in gas- analyzing applications for various gas species determination due to their low cost and possibility to detect number of different gases. However, one of the main problems with such sensors is their lack of selectivity. To overcome this issue different ap- proaches can be used. One of them is the operation with sensor temperature modulation combined with dedicated data process- ing...