Search
Filters
total: 2342
filtered: 2056
displaying 1000 best results Help
Search results for: FUNCTIONAL DIFFERENTIAL EQUATIONS
-
Geometrically nonlinear FEM analysis of 6-parameter resultant shell theory based on 2-D Cosserat constitutive model
PublicationWe develop the elastic constitutive law for the resultant statically and kinematically exact, nonlinear, 6-parameter shell theory. The Cosserat plane stress equations are integrated through-the- thickness under assumption of the Reissner-Mindlin kinematics. The resulting constitutive equations for stress resultant and couple resultants are expressed in terms of two micropolar constants: the micropolar modulus Gc and the micropolar...
-
Reduction of Computational Complexity in Simulations of the Flow Process in Transmission Pipelines
PublicationThe 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...
-
Ellipticity of gradient poroelasticity
PublicationWe discuss the ellipticity properties of an enhanced model of poroelastic continua called dilatational strain gradient elasticity. Within the theory there exists a deformation energy density given as a function of strains and gradient of dilatation. We show that the equilibrium equations are elliptic in the sense of Douglis–Nirenberg. These conditions are more general than the ordinary and strong ellipticity but keep almost all...
-
Elastic electron scattering and vibrational excitation of isoxazole molecules in the energy range from 2 to 20 eV
PublicationDifferential cross sections for elastic electron scattering and the excitation of the C-H vibrational modes of isoxazole molecules were measured in the energy range from 2 to 20 eV and over the scattering angle range from 10◦ to 180◦. The cross sections at the scattering angles of and above 90◦ were accessible with the use of a magnetic angle changer. The differential cross sections were integrated to yield integral and momentum...
-
Use of Sensory Analysis Methods to Evaluate the Odor of Food and Outside Air
PublicationSensory analysis is applied in many areas of daily life. It is used to carry out the sensory evaluation of foodstuffs or other products and to evaluate the properties of odors present in the environment. The authors attempt to summarize the knowledge on the classification and application of sensory analysis methods to evaluate the odor nuisance of air, which allows the identification of sensory impressions and determination of...
-
Projekt mechanizmu różnicowego do pojazdu samochodowego z zachowaniem wymogów jakościowych ISO/TS 16949
PublicationW artykule przedstawiono proces projektowania mechanizmu różnicowego. Dokonano wyboru koncepcji z pośród istniejących rozwiązań stosowanych obecnie w pojazdach samochodowych. Skupiono się przede wszystkim na przebiegu procesu wykonania prototypu z zachowaniem wymogów i standardów ISO/TS 16949 dla produktu i projektu.
-
Fractional Order Circuit Elements Derived from Electromagnetism
PublicationIn this paper, derivations of fractional-order (FO) circuit-element equations from electromagnetism are presented. Whilst many papers are devoted to FO modelling of electrical circuits, there are no strong foundations for such an approach. Therefore, we investigate relations between the FO electromagnetism and the FO circuit theory. Our derivations start from quasi-static (QS) approximations of Maxwell's equations in media with...
-
Automatic Discovery of IaaS Cloud Workload Types
PublicationThe paper presents an approach to automatic discovery of workloads types. We perform functional characteristics of the workloads executed in our cloud environment, that have been used to create model of the computations. To categorize the resources utilization we used K-means algorithm, that allow us automatically select six types of computations. We perform analysis of the discovered types against to typical computational benchmarks,...
-
Prebiotics and probiotics in food
PublicationNowadays, food is not only used to satisfy hunger and is a source of nutrients, but is also considered a factor that directly affects human health. Consumers are looking for high-quality products that contain bioactive ingredients that affect the proper functioning of the body and good mood. Functional foods, which must exhibit health benefits when consumed as part of a balanced diet, are becoming increasingly popular among health-conscious...
-
Ligand-Modified Boron-Doped Diamond Surface: DFT Insights into the Electronic Properties of Biofunctionalization
PublicationWith the increasing power of computation systems, theoretical calculations provide a means for quick determination of material properties, laying out a research plan, and lowering material development costs. One of the most common is Density Functional Theory (DFT), which allows us to simulate the structure of chemical molecules or crystals and their interaction. In developing a new generation of biosensors, understanding the nature...
-
N-point estimators of the Instantaneous Complex Frequency
PublicationIn this paper estimators of the instantaneous complex frequency (ICF) are presented and discussed. The differential approach for the estimation of the ICF is used, therefore the estimators are based on maximally flat N-point FIR filters: differential and delay. The investigation of the filter performance includes static characteristics of ICF estimation and the error of the ICF estimation in the discrete frequency domain.W pracy...
-
Asynchronous time difference of arrival (ATDOA) method
PublicationA new method for a location service in the asynchronous wireless sensor networks is outlined. This method, which is called asynchronous time difference of arrival (ATDOA), enables calculation of the position of a mobile node without knowledge of relative time differences (RTDs) between measuring sensors. The ATDOA method is based on the measurement of time difference of arrival between the node and the same sensor at the discrete...
-
On a fully three-dimensional bending analysis of very thick smart composite cube-like bulk structures
PublicationHere we discuss the behaviour of very thick composite plates considering electro-magneto-elastic coupling of various types using fully three-dimensional (3D) kinematics. Published research highlights a lack of studies on the 3D mechanics of smart composite plates that integrate both higher-order (flexoelectric/flexomagnetic) and lower-order (piezoelectric/piezomagnetic) multiple physical fields (electro-magneto-elastic). The common...
-
Bounded solutions of odd nonautonomous ODE
PublicationBorsuk-Ulam type argument is used in order to prove exstence of nontrivial bounded solutions to some nonautonomous differential euations which are odd with respect to the spatial variable. A Poincare compactification trick is also applied.
-
On the convergence of a nonlinear finite-difference discretization of the generalized Burgers–Fisher equation
PublicationIn this note, we establish analytically the convergence of a nonlinear finite-difference discretization of the generalized Burgers-Fisher equation. The existence and uniqueness of positive, bounded and monotone solutions for this scheme was recently established in [J. Diff. Eq. Appl. 19, 1907{1920 (2014)]. In the present work, we prove additionally that the method is convergent of order one in time, and of order two in space. Some...
-
Shub’s conjecture for smooth longitudinal maps of S^m
PublicationLet f be a smooth map of the m-dimensional sphere Sm to itself, preserving the longitudinal foliation. We estimate from below the number of fixed points of the iterates of f , reduce Shub’s conjecture for longitudinal maps to a lower dimensional classical version, and prove the conjecture in case m = 2 and in a weak form for m = 3.
-
Magnetoacoustic heating in a quasi-isentropic magnetic gas
PublicationThe nonlinear heating of a plasma which associates with the transfer of energy of magnetoacoustic waves into that of the entropy mode, is analytically studied. A plasma is uniform and motionless at equilibrium. Perturbations in a plasma are described by a system of ideal magnetohydrodynamic equations. The equilibrium straight magnetic strength and the wave vector form a constant angle which varies from 0 to π/2. There exist four...
-
Categorization of Cloud Workload Types with Clustering
PublicationThe paper presents a new classification schema of IaaS cloud workloads types, based on the functional characteristics. We show the results of an experiment of automatic categorization performed with different benchmarks that represent particular workload types. Monitoring of resource utilization allowed us to construct workload models that can be processed with machine learning algorithms. The direct connection between the functional...
-
On analog comparators for CMOS digital pixel applications. A comparative study
PublicationVoltage comparator is the only – apart from the light-to-voltage converter – analog component in the digital CMOS pixel. In this work, the influence of the analog comparator nonidealities on the performance of the digital pixel has been investigated. In particular, two versions of the digital pixel have been designed in 0.35 μm CMOS technology, each using a different type of analog comparator. The properties of both versions have...
-
Displacement Sensors Based on the Phase of the Reflection Coefficient of a Split Ring Resonator Loaded Transmission Line
Publication— In this paper, novel displacement sensors using a microstrip loaded with a pair of split ring resonators (SRRs) are proposed. It is shown that the phase of the reflection coefficient from the loading SRRs can be used for displacement sensing. The paper also proposes a differential version of the sensor that benefits from a higher sensitivity and reference zero, which is useful for alignment purposes. It is further shown that...
-
On Applications of Fractional Derivatives in Electromagnetic Theory
PublicationIn this paper, concepts of fractional-order (FO) derivatives are analysed from the point of view of applications in the electromagnetic theory. The mathematical problems related to the FO generalization of Maxwell's equations are investigated. The most popular formulations of the fractional derivatives, i.e., Riemann-Liouville, Caputo, Grünwald-Letnikov and Marchaud definitions, are considered. Properties of these derivatives are...
-
Nonlinear resultant theory of shells accounting for thermodiffusion
PublicationThe complete nonlinear resultant 2D model of shell thermodiffusion is developed. All 2D balance laws and the entropy imbalance are formulated by direct through-the-thickness integration of respective 3D laws of continuum thermodiffusion. This leads to a more rich thermodynamic structure of our 2D model with several additional 2D fields not present in the 3D parent model. Constitutive equations of elastic thermodiffusive shells...
-
Buckling analysis of a non-concentric double-walled carbon nanotube
PublicationOn the basis of a theoretical study, this research incorporates an eccentricity into a system of compressed double-walled carbon nanotubes (DWCNTs). In order to formulate the stability equations, a kinematic displacement with reference to the classical beam hypothesis is utilized. Furthermore, the influence of nanoscale size is taken into account with regard to the nonlocal approach of strain gradient and the van der Waals interaction...
-
Absorbing Boundary Conditions Derived Based on Pauli Matrices Algebra
PublicationIn this letter, we demonstrate that a set of absorbing boundary conditions (ABCs) for numerical simulations of waves, proposed originally by Engquist and Majda and later generalized by Trefethen and Halpern, can alternatively be derived with the use of Pauli matrices algebra. Hence a novel approach to the derivation of one-way wave equations in electromagnetics is proposed. That is, the classical wave equation can be factorized...
-
Fundamentals of classical and analytical mechanics
PublicationThe book is a monographic description of the present attempt to Newtonian and Lagrangian mechanics. But also, it could be found as a supplementary educational material useful for the graduate courses in mechanics taken by students majoring in mechanical engineering, physics or physical science. In the book you can find a brief introduction to concepts and principles of algebra of vectors; Kinematics of particles, mainly focused...
-
Quantum corrections to phi^4 model solutions and applications to Heisenberg chain dynamics
PublicationThe Heisenberg spin chain is considered in φ^4 model approximation. Quantum corrections to classical solutions of the one-dimensional φ^4 model within the correspondent physics are evaluated with account of rest d−1 dimensions of a d-dimensional theory. A quantization of the model is considered in terms of spacetime functional integral. The generalized zeta-function formalism is used to renormalize and evaluate the functional integral...
-
Quantum corrections to 4 model solutions and applications to Heisenberg chain dynamics
PublicationThe Heisenberg spin chain is considered in φ^4 model approximation. Quantum corrections to classical solutions of the one-dimensional φ^4 model within the correspondent physics are valuated with account of rest d − 1 dimensions of a d-dimensional theory. A quantization of the model is considered in terms of space- time functional integral. The generalized zeta-function formalism is used to renormalize and evaluate the functional...
-
Minimum drag shape bodies moving in inviscid fluid - revisited
PublicationThis paper presents the classic approach to minimum drag shape body problem, moving at hypersonic speeds, leading to famous power law shapes with value of the exponent of 3/4. Two- and three-dimensional cases are considered. Furthermore, an exact pseudo solution is given and its uselessness is discussed. Two new solutions are introduced, namely an approximate solution due to form of the functional and solution by means of optimisation...
-
Effects of laser pulse duration in two-photon vision threshold measurements
PublicationPulsed near-infrared (NIR) light sources can be successfully applied for both imaging and functional testing of the human eye, as published recently1. These two groups of applications have different requirements. For imaging applications, the most preferable is invisible scanning beam while efficiently visible stimulating beam is preferable for functional testing applications. The functional testing of human eye using NIR laser...
-
Respiratory compensation point during incremental test in overweight and normoweight boys: is it useful in assessing aerobic performance? A longitudinal study
Publication -
Will Music Give Me Power? Effects of Listening to Music during Active and Passive Rest Intervals on Power Output during Resistance Exercise
Publication -
Technique to improve CMRR at high frequencies in CMOS OTA-C filters
PublicationIn this paper a technique to improve the common-mode rejection ratio (CMRR) at high frequencies in the OTA-C filters is proposed. The technique is applicable to most OTA-C filters using CMOS operational transconductance amplifiers (OTA) based on differential pairs. The presented analysis shows that a significant broadening of CMRR bandwidth can be achieved by using a differential pair with the bodies of transistors connected to...
-
Geometrically nonlinear FEM analysis of FGM shells based on neutral physical surface approach in 6-parameter shell theory
PublicationThe paper presents the formulation of the elastic constitutive law for functionally graded materials (FGM) on the grounds of nonlinear 6-parameter shell theory with the 6th parameter being the drilling degree of freedom. The material law is derived by through-the-thickness integration of the Cosserat plane stress equations. The constitutive equations are formulated with respect to the neutral physical surface. The influence of...
-
A Nonlinear Model of a Mesh Shell
PublicationFor a certain class of elastic lattice shells experiencing finite deformations, a continual model using the equations of the so-called six-parameter shell theory has been proposed. Within this model, the kinematics of the shell is described using six kinematically independent scalar degrees of freedom — the field of displacements and turns, as in the case of the Cosserat continuum, which gives reason to call the model under consideration...
-
Electromagnetic-based derivation of fractional-order circuit theory
PublicationIn this paper, foundations of the fractional-order circuit theory are revisited. Although many papers have been devoted to fractional-order modelling of electrical circuits, there are relatively few foundations for such an approach. Therefore, we derive fractional-order lumped-element equations for capacitors, inductors and resistors, as well as Kirchhoff’s voltage and current laws using quasi-static approximations of fractional-order...
-
Macro-elements and Model Order Reduction for Efficient Three-Dimensional FEM Analysis
PublicationAn efficient model order reduction (MOR) methodology for three dimensional vector finite element method (FEM) is developed to accelerate simulations of the structures containing features that cause strong variations of mesh density. As the result of presented algorithm, FEM subsystems of equations corresponding to the selected refined region are converted into a very compact sets of linear equations, called macro-elements.Numerical...
-
On a 3D material modelling of smart nanocomposite structures
PublicationSmart composites (SCs) are utilized in electro-mechanical systems such as actuators and energy harvesters. Typically, thin-walled components such as beams, plates, and shells are employed as structural elements to achieve the mechanical behavior desired in these composites. SCs exhibit various advanced properties, ranging from lower order phenomena like piezoelectricity and piezomagneticity, to higher order effects including flexoelectricity...
-
The Realization of NGN Architecture for ASON/GMPLS Network
PublicationFor the last decades huge efforts of telecommunication,Internet and media organizations have been focusingon creating standards and implementing one common networkdelivering multimedia services - Next Generation Network.One of the technologies which are very likely to beused in NGN transport layer is ASON/GMPLS optical network.The implementation of ASON/GMPLS technology usingopen source software and its results are the subject...
-
Bezpieczeństwo funkcjonalne i ochrona informacji w obiektach i systemach infrastruktury krytycznej - analiza i ocena
PublicationW niniejszym rozdziale monografii przedstawiono bardzo aktualną problematykę związaną z analizą bezpieczeństwa funkcjonalnego rozproszonych systemów sterowania i automatyki zabezpieczeniowej w obiektach infrastruktury krytycznej, wykorzystujących przemysłową sieć komputerową, z uwzględnieniem zagadnień ochrony informacji. W obiektach tego typu systemy sterowania i automatyki zabezpieczeniowej są projektowane jako systemy rozproszone,...
-
The Doppler effect in a bistatic system for determining the position of moving targets
PublicationThe article presents the theoretical analysis and the results of numerical calculations of the Doppler effect it occurs in a system designed to determine the position and speed of a moving target. The transmitter is the source of the signal and it emits a sinusoidal, acoustic and continuous wave. Signal reflected off a moving target is received by four hydrophones. Based on the signals, four Doppler shifts are determined and inserted...
-
generation of the vorticity mode by sound in a bingham plastic
PublicationThis 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...
-
Bending analysis of functionally graded nanoplates based on a higher-order shear deformation theory using dynamic relaxation method
PublicationIn this paper, bending analysis of rectangular functionally graded (FG) nanoplates under a uniform transverse load has been considered based on the modified couple stress theory. Using Hamilton’s principle, governing equations are derived based on a higher-order shear deformation theory (HSDT). The set of coupled equations are solved using the dynamic relaxation (DR) method combined with finite difference (FD) discretization technique...
-
Weryfikacja Poziomów Nienaruszalności Bezpieczeństwa z uwzględnieniem Zagadnień Ochrony Informacji
PublicationNiniejszy rozdział poświęcono wybranym istotnym zagadnieniom analizy bezpieczeństwa funkcjonalnego, w szczególności weryfikacji poziomów nienaruszalności bezpieczeństwa SIL funkcji bezpieczeństwa implementowanych w rozproszonych systemach sterowania i zabezpieczeń z uwzględnieniem zagadnień ochrony informacji. Zaproponowano metodę opartą na informacji ilościowej i jakościowej do weryfikacji SIL (IEC 61508, 61511) z uwzględnieniem...
-
Numerical solutions for blood flow in elastic vessels
PublicationWe consider the differential–algebraic system for the blood flow and pressure in the systemic arteries. By the operator splitting method, we transform the system into the hyperbolic one, introduce the bicharacteristics, and perform the time–space nonuniform discretization, obtaining the innovative difference scheme. Our results are illustrated with numerical experiments.
-
Calculating the Partition Coefficients of Organic Solvents in Octanol/Water and Octanol/Air
PublicationPartition coefficients define how a solute is distributed between two immiscible phases at equilibrium. The experimental estimation of partition coefficients in a complex system can be an expensive, difficult, and time-consuming process. Here a computational strategy to predict the distributions of a set of solutes in two relevant phase equilibria is presented. The octanol/water and octanol/air partition coefficients are predicted...
-
Public spaces connecting cities. Green and Blue Infrastructures potential.
PublicationA city fragmentation causes a lot of negative effects in urban environment such as: disconnecting the environmental, functional and compositional relations, a loss of urban compactness, chaotic development, visual chaos, a domination of technical landscape, reduction of security. This is why one of main challenges for urban planners is to connect the fragmented structures by creating friendly, attractive and safe public space....
-
Mobilny system do detekcji obiektów ferromagnetycznych z magnetometrami pompowanymi optycznie
PublicationW pracy przedstawiono mobilny system do detekcji obiektów ferromagnetycznych. Każdy obiekt ferromagnetyczny zaburza w swoim otoczeniu równomierność pola magnetycznego Ziemi. Zaburzenie to może być zmierzone za pomocą precyzyjnych magnetometrów. W prezentowanym mobilnym systemie zastosowano magnetometry pompowane optycznie pracujące w układzie różnicowym. W pracy opisano magnetometryczny system do detekcji obiektów ferromagnetycznych,...
-
Formulation of Time-Fractional Electrodynamics Based on Riemann-Silberstein Vector
PublicationIn this paper, the formulation of time-fractional (TF) electrodynamics is derived based on the Riemann-Silberstein (RS) vector. With the use of this vector and fractional-order derivatives, one can write TF Maxwell’s equations in a compact form, which allows for modelling of energy dissipation and dynamics of electromagnetic systems with memory. Therefore, we formulate TF Maxwell’s equations using the RS vector and analyse their...
-
Ellipticity in couple-stress elasticity
PublicationWe discuss ellipticity property within the linear couple-stress elasticity. In this theory, there exists a deformation energy density introduced as a function of strains and gradient of macrorotations, where the latter are expressed through displacements. So the couple-stress theory could be treated as a particular class of strain gradient elasticity. Within the micropolar elasticity, the model is called Cosserat pseudocontinuum...
-
Wpływ błędów parametrów modelu maszyny indukcyjnej na działanie rozszerzonego obserwatora prędkości
PublicationW artykule opisano metodę odtwarzania prędkości wirnika maszyny indukcyjnej przy wykorzystaniu rozszerzonego obserwatora prędkości. Zbadano wpływ błędów parametrów modelu maszyny indukcyjnej na właściwości dynamiczne obserwatora poprzez porównanie macierzy stanu obserwatora obarczonego oraz nieobarczonego błędami parametrów. Zbadany został także wpływ błędów parametrów na jakość odtwarzania zmiennych maszyny w stanie ustalonym.