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Electron diffision coefficients in triatomic gases measurements and model
PublikacjaPraca zawiera porównanie współczynników dyfuzji elektronów w gazach trójatomowych (N2O, C2O) zmierzonych w doświadczeniu ze współczynnikami wyznaczonymi numerycznie z wykorzystaniem równania Boltzmanna oraz z zastosowaniem metody Monte Carlo. Przedstawiona procedura pozwala zweryfikować przekroje czynne na zderzenia elektronów z drobinami gazów.
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Parametric method applicable in assessing breakout force and time for lifting slender bodies from seabed
PublikacjaThe article presents a parametric method applicable in assessing the suction force of a slender body to the seabed, and prognosing the body extrication time. Along with the body weight in water, the information on the suction force is essential for assessing the force needed to lift the object from the seabed. Based on the Foda theory and the resulting integral equation, which relates the maximum suction force with basic parameters...
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Co-simulation strategy of transient CFD and heat transfer in building thermal envelope based on calibrated heat transfer coefficients
PublikacjaThe paper presents a strategy to develop a fully transient numerical model of a heat transfer in building, using a transient CFD model of indoor air and a thermal envelope model, running in a co-simulation. The strategy relies on the utilization of RANS with a high-Re turbulence model and a wall function, which enables to use a coarse computational mesh limiting the computational time. Since wall functions give invalid heat transfer...
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Piezoresponse force microscopy and dielectric spectroscopy study of Ba0.6Sr0.4TiO3 thin films
PublikacjaResearch on synthesis, characterization and determination of processing – structure – property relationships of commercially important ferroelectric thin films has been performed. The sol-gel-type solution deposition technique was applied to produce good quality thin films of Ba0.6Sr0.4TiO3 (BST60/40) chemical composition on the stainless steel substrates. The thin films were characterized in terms of their microstructure, crystal...
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Central-force decomposition of spline-based modified embedded atom method potential
PublikacjaCentral-force decompositions are fundamental to the calculation of stress fields in atomic systems by means of Hardy stress. We derive expressions for a central-force decomposition of the spline-based modified embedded atom method (s-MEAM) potential. The expressions are subsequently simplified to a form that can be readily used in molecular-dynamics simulations, enabling the calculation of the spatial distribution of stress in...
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Modeling the Structure, Dynamics, and Transformations of Proteins with the UNRES Force Field
PublikacjaThe physics-based united-residue (UNRES) model of proteins ( www.unres.pl ) has been designed to carry out large-scale simulations of protein folding. The force field has been derived and parameterized based on the principles of statistical-mechanics, which makes it independent of structural databases and applicable to treat nonstandard situations such as, proteins that contain D-amino-acid residues. Powered by Langevin dynamics...
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Homoclinics for singular strong force Lagrangian systems in R^N
PublikacjaWe will be concerned with the existence of homoclinics for second order Hamiltonian systems in R^N (N>2) given by Hamiltonians of the form H(t,q,p)=Φ(p)+V(t,q), where Φ is a G-function in the sense of Trudinger, V is C^2-smooth, periodic in the time variable, has a single well of infinite depth at a point ξ and a unique strict global maximum 0 at the origin. Under a strong force type condition aroud the singular point ξ, we prove...
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Characteristic of Morpholinium Ionic Liquids as Gas Chromatography Stationary Phases with McReynolds Constants and Activity Coefficients at Infinite Dilution
PublikacjaIn this work, four ionic liquids based on N-alkyl-N-methylmorpholinium cation ([Mor1,R] where R= 2, 4, 8, 10) and bis(trifluoromethanesulfonyl)imide anion [TFSI] were synthesized. Using gas-liquid chromatography a number of parameters describing the sorption properties of the investigated ionic liquids were determined. The values of Kovats indices, McReynolds constants, and activity coefficients at infinite dilution were the basis...
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The Role of Electrostatics in Enzymes: Do Biomolecular Force Fields Reflect Protein Electric Fields?
PublikacjaPreorganization of large, directionally oriented, electric fields inside protein active sites has been proposed as a crucial contributor to catalytic mechanism in many enzymes, and it may be efficiently investigated at the atomistic level with molecular dynamics simulations. Here, we evaluate the ability of the AMOEBA polarizable force field, as well as the additive Amber ff14SB and Charmm C36m models, to describe the electric...
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Shape and force control of cable structures with minimal actuators and actuation
PublikacjaShape adjustment and stress control can be considered as one of the effective parameters in prestressed cable structures since such structures are widely constructed nowadays due to their characteristics. The assembly errors and applied loads hugely affect the cables’ nodal positions and stress due to their delicacy. The former could disturb the shape, which affects the appearance and the function of the structure. In contrast,...
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PROBLEMS OF EXPERIMENTAL DETERMINATION OF COEFFICIENTS OF THE WEAR OF SHIP PIPING SYSTEMS
PublikacjaThe article presents series of considerations relating to experimental evaluation of the reliability of ship piping systems. The aim of this study is to attempt to answer the following questions: What should be the tested element? How to choose the diameter of the tested item? What should be the result of measurements and calculations? How to measure? How to choose the duration of the test? How to choose the sample size and elaborate...
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Coupling coefficients for the space group of the hexagonal close-packed structure
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Cation diffusion coefficients in CuAgI via molecular dynamics simulations
PublikacjaPraca prezentuje wyniki analizy strukturalnej otrzymane poprzez symulacje dynamiczno-molekularne (zespół NpT, dwuciałowy potencjał Vashisty-Rahmana) superjonowego związku o składzie (1-x)Cu-xAg-I, x = 0.0, 0.25, 0.5, 0.75, 1.0). Wyznaczono wartość współczynnika dyfuzji kationów i energii aktywacji w funkcji składu szkła i temperatury. Otrzymane rezultaty porównano z danymi literaturowymi.
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Electron scattering on N2O - from cross section to diffusion coefficients.
PublikacjaW pracy przedstawiono wyniki pomiarów współczynników transportu: stosunek współczynnika dyfuzji w kierunku prostopadłym do pola elektrycznego do ruchliwości, stosunek współczynnika dyfuzji podłużnej do ruchliwości oraz prędkość dryfu elektronów w funkcji zredukowanego pola elektrycznego. Współczynniki zmierzono metodą Townsenda-Huxley´a a prędkość dryfu otrzymano wykorzystując metodę Bradbury - Nielsena. Zmierzone współczynniki...
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Two families of infinitely many homoclinics for singular strong force Hamiltonian systems
PublikacjaWe are concerned with a planar autonomous Hamiltonian system with a potential possessing a single well of infinite depth at a point X and a unique strict global maximum 0 at a point A. Under a strong force condition around the singularity X, via minimization of an action integral and using a shadowing chain lemma together with simple geometrical arguments, we prove the existence of infinitely many geometrically distinct homoclinic...
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Nonlinear planar modeling of massive taut strings travelled by a force-driven point-mass
PublikacjaThe planar response of horizontal massive taut strings, travelled by a heavy point-mass, either driven by an assigned force, or moving with an assigned law, is studied. A kinematically exact model is derived for the free boundary problem via a variational approach, accounting for the singularity in the slope of the deflected string. Reactive forces exchanged between the point-mass and the string are taken into account via Lagrange...
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Modeling protein structures with the coarse-grained UNRES force field in the CASP14 experiment
PublikacjaThe UNited RESidue (UNRES) force field was tested in the 14th Community Wide Experiment on the Critical Assessment of Techniques for Protein Structure Prediction (CASP14), in which larger oligomeric and multimeric targets were present compared to previous editions. Three prediction modes were tested (i) ab initio (the UNRES group), (ii) contact-assisted (the UNRES- contact group), and (iii) template-assisted (the UNRES-template...
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Evaluation of Gas Chromatography Stationary Phases Based on Morpholinium Ionic Liquids by McReynolds Constants and Activity Coefficients at Infinite Dilution
PublikacjaIn this work, four ionic liquids (ILs) based on the N-alkyl-N-methylmorpholinium cation ([Mor1,R], in which R = 2, 4, 8, or 10) and bis (trifluoromethanesulfonyl)imide anion were synthesized. Using GLC, a number of parameters describing the sorption properties of the investigated ILs were determined. The values of Kovats indices, McReynolds constants, and activity coefficients at infinite dilution were the basis for the evaluation...
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Coefficients for Assessing the Visibility of Materials Used in Anti-Smog Face Masks
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Determination of Propeller-Rudder-Hull Interaction Coefficients in Ship Manoeuvring Prediction
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Experimental analysis of coefficients of local resistance on elbows in multilayer pipe systems
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Standing Waves in One-Dimensional Resonator Contaning an Ideal Isothermal Gas Affected by the Constant Mass Force
PublikacjaThe study is devoted to standing acoustic waves in one-dimensional planar resonator which containing an ideal gas. A gas is affected by the constant mass force. Two types of physically justified boundary conditions are considered: zero velocity or zero excess pressure at both boundaries. The variety of nodal and antinodal points is determined. The conclusion is that the nodes of pressure and antinodes of velocity do not longer...
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Nonlinear free and forced vibrations of a dielectric elastomer-based microcantilever for atomic force microscopy
PublikacjaThe majority of atomic force microcode (AFM) probes work based on piezoelectric actuation. However, some undesirable phenomena such as creep and hysteresis may appear in the piezoelectric actuators that limit their applications. This paper proposes a novel AFM probe based on dielectric elastomer actuators (DEAs). The DE is modeled via the use of a hyperelastic Cosserat model. Size effects and geometric nonlinearity are included...
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Atomic Force Microscope data post-processing algorithm for higher harmonics imaging
PublikacjaPrevious works have proved that higher harmonics topography imaging using atomic force microscope (AFM) can significantly enhanced its measurement capabilities. Integrated tools dedicated to most of microscopes allow to visualize the investigated surface only by one selected harmonic. Because of the different characteristics of a sample, scanning tip and the environment, appropriate harmonic selection is time consuming and requires...
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Problem of proper decomposition and initialization of acoustic and entropy modes in a gas affected by the mass force
PublikacjaThe relations connecting perturbations specific for acoustic and entropy modes in an accelerated fluid or in a fluid affected by constant mass force, are derived. They allow to decompose the total vector of perturbations and the overall energy into acoustic and non-acoustic parts uniquely at any instant. In order to do this, three quantities are required, for example total perturbations in entropy, pressure and velocity. The evaluations...
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Measurement system for nonlinear surface spectroscopy by atomic force microscopy for corrosion processes monitoring
PublikacjaIn addition to traditional imaging the surface, atomic force microscopy (AFM) enables wide variety of additional measurements. One of them is higher harmonic imaging. In tapping mode the nonlinear contact between tip and specimen results in higher frequency vibrations. More information available from the higher harmonics analysis proves to be helpful for more detailed imaging. Such visualization is especially useful for heterogeneous...
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Decomposition of Acoustic and Entropy Modes in a Non-Isothermal Gas Affected by a Mass Force
PublikacjaDiagnostics and decomposition of atmospheric disturbances in a planar flow are considered in this work. The study examines a situation in which the stationary equilibrium temperature of a gas may depend on the vertical coordinate due to external forces. The relations connecting perturbations are analytically established. These perturbations specify acoustic and entropy modes in an arbitrary stratified gas affected by a constant...
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Extension of the Force Matching Method to Anisotropic Coarse-Grained Transferable Force Fields: Application to the Unres Model of Proteins
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Parametric method applicable in calculating breakout force and time for lifting axisymmetric objects from seabed.
PublikacjaThe issue of calculating parameters for lifting objects of axisymmetric shapes from the seabed is studied. The article presents the results of numerical simulation examination of the equation formulated by Foda for the force needed to extricate the object from the seabed depending on soil and water parameters, extrication speed, and object diameter. The simulations were performed within the range of parameters characteristic for...
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Relieving the Measuring System of the Trailer for Tyre/Road Rolling Resistance Measurements from the Inertia Force
PublikacjaIn the article the principle of measuring of tyre/road rolling resistance tyres in road conditions applied in a special measuring trailer is presented. This trailer was built in Faculty of Mechanical Engineering at Gdansk University of Technology. The construction of two special devices used in this trailer was discussed. These devices eliminate the influence of some chosen confounding measurements factors such as: the inertia...
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A measurement system for nonlinear surface spectroscopy with an atomic force microscope during corrosion process monitoring
PublikacjaIn addition to traditional imaging the surface, atomic force microscopy (AFM) enables wide variety of additional measurements. One of them is higher harmonic imaging. In tapping mode the nonlinear contact between tip and specimen results in higher frequency vibrations. More information available from the higher harmonics analysis proves to be helpful for more detailed imaging. Such visualization is espe-cially useful for heterogeneous...
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Decoding of the FSK signal with noise and distortion with the use of coefficients of the time-frequency transform.
PublikacjaStreszczenie: Przeanalizowano sygnał z modulacją FSK wykorzystując metodę transformacji czasowo-częstotliwościowej różniące się sposobem podziału płaszczyzny TF na atomy: krótko-okresowej transformacji Fouriera, transformacji falkowej i transformacji pakietami falkowymi. Transformacja falkowa zapewnia dobrą lokalizację czasową zakłóceń o wielkiej częstotliwości, podczas gdy transformacja pakietami falkowymi zapewnia dobrą lokalizację...
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A Maximum-Likelihood Approach to Force-Field Calibration
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TINKTEP: A fully self-consistent, mutually polarizable QM/MM approach based on the AMOEBA force field
PublikacjaWe present a novel quantum mechanical/molecular mechanics (QM/MM) approach in which a quantum subsystem is coupled to a classical subsystem described by the AMOEBA polarizable force field. Our approach permits mutual polarization between the QM and MM subsystems, effected through multipolar electrostatics. Self-consistency is achieved for both the QM and MM subsystems through a total energy minimization scheme. We provide an expression...
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Force transfer and stress distribution in short cantilever deep beams loaded throughout the depth with a various reinforcement
PublikacjaDeep beams used as the main reinforced concrete structural elements which taking over the load and stiffening construction are often found in high-rise buildings. The architecture of these buildings is sometimes sophisticated and varied, arouse the admiration of the majority of recipients, and thus causing an engineering challenge to correctly design the structural system and force transfer. In such structures is important to shape...
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Performance of extended Lagrangian schemes for molecular dynamics simulations with classical polarizable force fields and density functional theory
PublikacjaIterative energy minimization with the aim of achieving self-consistency is a common feature of Born-Oppenheimer molecular dynamics (BOMD) and classical molecular dynamics with polarizable force fields. In the former, the electronic degrees of freedom are optimized, while the latter often involves an iterative determination of induced point dipoles. The computational effort of the self-consistency procedure can be reduced by re-using...
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Dissipated energy minimization in a combustion engine Mount system by position dependent damping coefficients
PublikacjaPraca opisuje rozważania na temat możliwości tłumienia drgań spalinowego silnika czterosuwowego. Do modelowania wykorzystano zasady dynamiki układów wielomasowych. Przedstawiono krótki opis wspomnianego sposobu modelowani. Zbudowano model numeryczny silnika. Model poddano analizie numerycznej. Podczas analizy dynamiki układu skoncentrowano się na elementach tłumiących drgania, obecnych w zawieszeniu silnika oraz na analizie wpływu...
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Measurement of activity coefficients at infinite dilution of organic solutes in the ionic liquid 1-hexyl-1,4-diaza[2.2.2]bicyclooctanium bis(trifluoromethylsulfonyl)imide using gas–liquid chromatography
PublikacjaBased on gas–liquid chromatography (GLC) retention data, activity coefficients at infinite dilution of 39 different solutes in the ionic liquid 1-hexyl-1,4-diaza[2.2.2]bicyclooctanium bis(trifluoromethylsulfonyl)imide ([HDABCO][NTf2]) have been determined. Measurements covered a broad range of types of organic solutes including alkanes, alcohols, ketones, benzene derivatives and McReynold’s compounds. Activity coefficients were...
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ECONOMIC GROWTH AND FEMALE LABOR FORCE PARTICIPATION – VERIFYING THE U-FEMINIZATION HYPOTHESIS. NEW EVIDENCE FOR 162 COUNTRIES OVER THE PERIOD 1990-2012.
PublikacjaThe paper contributes by providing new insights into relationship between female labor force and economic growth in 162 world countries over the period 1990-2012. It is anticipated uncovering U-shaped relationship between female labor force participation and economic growth. The analysis is run in two different perspectives – first the relationship is examined for sample encompassing 162 countries; and second – the evidence is...
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Application of dynamic impedance spectroscopy to atomic force microscopy
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Pounding force response spectrum under earthquake excitation
PublikacjaW artykule przedstawiono możliwość wykorzystania spektrum siły zderzenia jako zaproponowanego przez autora narzędzia pomocnego przy projektowaniu budynków narażonych na zderzenia podczas trzęsień ziemi. Przedstawione wykresy spektrów pokazały, iż właściwy dobór parametrów budowli, takich jak szerokość przerwy pomiędzy budynkami, okres drgań własnych konstrukcji, liczba tłumienia, masa, współczynnik ciągliwości, czy też przesunięcie...
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Simulation of Force Spectroscopy Experiments on Galacturonic Acid Oligomers
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Visualization and characterization of prolamellar bodies with atomic force microscopy
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The protein folding problem: global optimization of force fields
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Application of dynamic impedance spectroscopy to atomic force microscopy
PublikacjaMikroskopia sił atomowych jest uniwersalną techniką obrazowania powierzchni podczas gdy spektroskopia impedancyjna jest fundamentalną metodą charakteryzowania właściwości elektrycznych materiałów. Z powyższego względu użyteczne jest połączenie powyższych technik dla uzyskania przestrzennego rozkładu wektora impedancji. W pracy autorzy proponują nowe podejście polegające na połączeniu multiczęstotliwościowego pomiaru impedancyjnego...
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Decomposition of the wall force acting on the single bubble motion.
PublikacjaW referacie skupiono uwagę na rozkładzie siły hydrodynamicznej działającej na kulę (uproszczony model pęcherzyka) na kierunku prostopadłym do ścianki kanału. Pokazano stanowisko badawcze, omówiono procedurę pomiarową oraz zamiszczono przykładowe wyniki badań eksperymentalnych i modelowania matematycznego.
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Extension of the force-matching method to coarse-grained models with axially symmetric sites to produce transferable force fields: Application to the UNRES model of proteins
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Measurements of Activity Coefficients at Infinite Dilution for Organic Solutes in the Ionic Liquids N-Ethyl- and N-Octyl-N-methylmorpholinium Bis(trifluoromethanesulfonyl)imide. A Useful Tool for Solvent Selection
PublikacjaIn recent years, many papers describing ionic liquids (IL) as promising solvents in separation techniques have been published. The conscious choice of appropriate ionic liquid as absorption media in effective extraction of selected types of analytes requires deeper understanding of the analyte−IL interactions. Therefore, intensive research is conducted to determine the values of activity coefficient at infinite dilution, which...
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Numerical modeling of force and contact networks in fragmented sea ice
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Synthetic jet actuator efficiency based on the reaction force measurement
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