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Search results for: SCREW DISPLACEMENT PILES, PILE SETTLEMENT CHARACTERISTIC, NUMERICAL SIMULATIONS, FINITE ELEMEMENT METHOD, ZSOIL
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The contribution of Hans von Wartenberg to the development of the Czochralski method
PublicationThe contribution of Hans von Wartenberg to the development of the Czochralski Method for pulling single crystals is often overlooked. He was its earliest adopter, having introduced the use of seed crystals, and his detailed description of the method was the basis for its subsequent dissemination.
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Rothe’s method for physiologically structured models with diffusion
PublicationWe consider structured population models with diffusion and dynamic boundary conditions. The respective approximation, called Rothe’s method, produces positive and exponentially bounded solutions. Its solutions converge to the exact solution of the original PDE.
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Numerical simulation of the influence of the selected factors on the performance of a concrete road barrier H2/W5/B
PublicationThis paper discuss the influence of selected factors on the performance of a concrete road barrier H2/W5/B. Modelling techniques of a concrete road safety system were briefly discussed. Comparison to the full scale crash test results has been shown. The concrete road safety barrier has been investigated for evaluation of the overall damage after collision under various initial conditions. The failure assessment criterion has been...
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Expedited Globalized Antenna Optimization by Principal Components and Variable-Fidelity EM Simulations: Application to Microstrip Antenna Design
PublicationParameter optimization, also referred to as design closure, is imperative in the development of modern antennas. Theoretical considerations along with rough dimension adjustment through supervised parameter sweeping can only yield initial designs that need to be further tuned to boost the antenna performance. The major challenges include handling of multi-dimensional parameter spaces while accounting for several objectives and...
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Search for the most useful geometry of an acoustic journal bearing
PublicationComputer simulations of a number of journal bearing’s geometries utilising acoustic levitation were carried out. The choice of the best geometry depended on the ability of a deformed shape, created by piezo-electric elements, to facilitate squeeze film ultrasonic levitation, and also to create three evenly distributed diverging aerodynamic gaps. Deformations of analysed variants of the bearing’s shape were generated by numerical...
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Assessing groundwater vulnerability to pollution in the Puck region (denudation moraine upland) using vertical seepage method
PublicationDegradation of groundwater quality can cause a serious water supply and environmental problems. The identify of potential groundwater pollution can be determined by assessment of groundwater vulnerability method. The assessment of groundwater vulnerability to pollution was based on estimation of migration time of potential conservative contamination through the vadose zone. Area of investigation is a type of denudation moraine...
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Fabrication of Bi6Fe2Ti3O18 Ceramics by Mixed Oxide Method
PublicationIn the present study Bi6Fe2Ti3O18 (BFTO) ceramics has been fabricated by solid state reaction from the mixture of simple oxides viz. Bi2O3, TiO2 and Fe2O3. Stoichiometric mixture of the powders was thermally analyzed so parameters of the thermal treatment were determined. The EDS measurements have shown conservation of the chemical composition of the ceramic powder after calcination. Hot-pressing method was used for final densification...
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Separation of variables in molecular-dynamics simulations: A criterion to estimate the quality of the approximation
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Star Polymers vs. Dendrimers: Studies of the Synthesis Based on Computer Simulations
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Molecular dynamics simulations of the growth of poly(chloro-para-xylylene) films
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Modelling of soft fault propagation in sequential circuits by fuzzy-logic simulations
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Molecular dynamics simulations of the growth of poly (chloro-para-xylylene) films.
PublicationParylene C, poly(chloro-para-xylylene) is the most widely used member of the parylene family due to its excellent chemical and physical properties. In this work we analyzed the formation of the parylene C film using molecular mechanics and molecular dynamics methods. A five unit chain is necessary to create a stable hydrophobic cluster and to adhere to a covered surface. Two scenarios were deemed to take place. The obtained results...
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A simplified behavioral MOSFET model based on parameters extraction for circuit simulations.
PublicationThe paper presents results on behavior modeling of general purpose Metal-Oxide Semiconductor Field-Effect Transistor (MOSFET) for simulation of power electronics systems requiring accuracy both in steady-state and in switching conditions. Methods of parameters extraction including nonlinearity of parasitic capacitances and steady-state characteristics are based on manufacturer data sheet and externally measurable characteristics....
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From flow to jamming: Lattice Gas Automaton simulations in granular materials
PublicationWe introduce the first extension of a Lattice Gas Automaton (LGA) model to accurately replicate observed emergent phenomena in granular materials with a special focus on previously unexplored jamming transitions by incorporating gravitational effects, energy dissipation in particle collisions, and wall friction. We successfully reproduce flow rate evolution, density wave formation, and jamming transition observed in experiments....
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EFFICIENT LINE DETECTION METHOD BASED ON 2D CONVOLUTION FILTER
PublicationThe article proposes an efficient line detection method using a 2D convolution filter. The proposed method was compared with the Hough transform, the most popular method of straight lines detection. The developed method is suitable for local detection of straight lines with a slope from -45˚ to 45˚. Also, it can be used for curve detection which shape is approximated with the short straight sections. The new method is characterized...
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On the use of a charge balancing method for low energy measurements
PublicationThe paper presents the method for the estimation of the energy consumption of the low-power microcontroller-based devices. Due to high dynamics of the changes of the supply current of the tested devices during the operational cycle, the consumed energy estimation is not easy. In order to avoid disadvantages of known methods, the charge balancing method was employed similarly like in some types of A/D converters.
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Engineering method of tire rolling resistance evaluation
PublicationTire rolling resistance is one of the most difficult tire parameters to measure. The reason is that for modern tires the force of rolling resistance corresponds to 0.5–1% of tire load, thus measurements of very small forces must be performed in a heavily loaded system. This constitutes great problems, especially in road conditions. Laboratory measurements are easier to perform, as the environment may be better controlled, but roadwheel...
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A VISION-BASED UNMANNED AERIAL VEHICLE NAVIGATION METHOD
PublicationThe satellite navigation systems are the main position sources for unmanned aerial vehicles (UAVs). This fact limits the area of UAVs operation to the places where radio signals is visible for a satellite navigation system receiver, mounted on the vehicle-outdoor navigation. Closed spaced are unavailable for vehicles which navigation is based on global satellite navigation systems (GNSS). Miniature UAV (MiniUAV) is able to operate...
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Verification of the method of reconstructing convective velocity fields on the basis of temperature fields in vertical, differential and equally heated, open and closed channels
PublicationThis paper describes a method of reconstructing velocity fields, i.e. a numerical reconstruction procedure (NRP) that involves the numerical processing of experimentally measured temperature distributions in free convection heat transfer. The NRP consists in solving only the continuity and Navier–Stokes equations with an additional source term. This term is proportional to a known temperature (e.g. from a thermal imaging camera)...
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Expert assessment of arguments: a method and its experimental evaluation
PublicationArgument structures are commonly used to develop and present cases for safety, security and other properties. Such argument structures tend to grow excessively. To deal with this problem, appropriate methods of their assessment are required. Two objectives are of particular interest: (1) systematic and explicit assessment of the compelling power of an argument, and (2) communication of the result of such an assessment to relevant...
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Low Cost Method for Location Service in the WCDMA System
PublicationA new and low cost method for a location service (LCS) in the Wideband Code Division Multiple Access (WCDMA) system is outlined. This method, which is called TDOA + RTT, enables calculation of the geographical position of a mobile station (MS) without knowledge of relative time differences (RTDs) between base stations (BSs). The TDOA+RTT method is based on the measurement of round trip times (RTTs) between the MS and the serving...
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Development of Local IDF-formula Using Controlled Random Search Method for Global Optimization
PublicationThe aim of the study is to present the effective and relatively simple empirical approach to rainfall Intensity-Duration-Frequency-formulas development, based on Controlled Random Search (CRS) for global optimization. The approach is mainly dedicated to the cases in which the commonly used IDF-relationships do not provide satisfactory fit between simulations and observations, and more complex formulas with higher number of parameters...
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Analysis of Accuracy of Modified Gradient Method in Indoor Radiolocalisation System
PublicationIn this paper a new method, called modified gradient method, has been proposed for position calculation on the basis of distance measurement in indoor environment. It is shown that well known method of position calculation such as Foy is inefficient in indoor environment. In this article is also described the indoor radiolocalisation system which was used for collecting distance measurements which were employed for further comparative...
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Verification of punching shear outside the shear cap by the direct method
PublicationThe proposition of a method to verify the punching resistance for very large supports based on the EN 1992-1-1 standard is described in this paper. The present standard guidelines for the calculation of the punching resistance for large supports are also summarised. The proposed direct method is compared with other standard methods using an example taken from design practice. This method consists of a direct check of the shear...
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Evaluation of the fast impedance spectroscopy method in the laboratory measurement system
PublicationIn this paper the method for fast impedancespectroscopy of technical objects with very high impedance(|Zx| ≥ 1 GΩ) is evaluated by means of simulation and practicalexperiment. The method is based on excitation of an object, witha square pulse and measurements of voltage and currentresponses with DAQ card. The object impedance spectrum isobtained with use of continuous Fourier transform. Someimprovements of the method concerned...
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A Method of MOS Evaluation for Video Based Services
PublicationThis paper deals with a method for QoE evaluation for the services transmitting large amount of data perceived by the end user in relatively short time periods, e.g. streaming video in mobile operator...
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Port-based approach to distributed transfer function method
PublicationIn the paper there is presented an uniform, port-based approach to modeling of both lumped and distributed parameter systems. Port-based model of distributed system has been defined by application of distributed transfer function method (DTFM). The approach proposed combines versatility of port - based modeling and accuracy of distributed transfer function method. It enables to formulate appropriate input data for computer analysis...
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The effect of fishing basin construction on the behaviour of a footbrdge over the port channel
PublicationThe paper analyses possible causes of failure of the rotating footbridge over the Ustka port channel. In July, 2015, strange behaviour of this object was observed in the form of excessive vibrations of bridge platform suspension rods, with the accompanying acoustic effects. A preliminary geotechnical analysis has revealed that this destructive effect was caused by the nearby construction works, namely construction of a fishing...
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Charakterystyka stopu Ł83 wytworzonego metodami odlewania i natryskiwania cieplnego = Characteristic of the Ł83 alloy fabricated by casting and thermal spraying methods
PublicationPrzedstawiono mikrostrukturę i twardość stopu łożyskowego Ł83 wytworzonego metodami natryskiwania cieplnego i odlewania odśrodkowego. W tym aspekcie dokonano analizy przydatności metody natryskiwania w produkcji łożysk ślizgowych.
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"Creating a numerical model of noise conditions based on the analysis of traffic volume changes in cities with low and medium structure.
PublicationThe subject of this research study is to analyze noise conditions of the selected area in the city of Gdańsk using data related to traffic volume changes during a day. This is because daily distribution of noise levels is much more helpful for noise control and reduction than traditional maps with Lden levels indicated. Calculations are made with the use of a numerical model developed at the Gdansk Univ. of Technology and implemented...
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"Creating a numerical model of noise conditions based on the analysis of traffic volume changes in cities with low and medium structure.
PublicationThe subject of this research study is to analyze noise conditions of the selected area in the city of Gdańsk using data related to traffic volume changes during a day. This is because daily distribution of noise levels is much more helpful for noise control and reduction than traditional maps with Lden levels indicated. Calculations are made with the use of a numerical model developed at the Gdansk Univ. of Technology and implemented...
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Usefulness of the voltamperometric method for assessment of the purity of soil
PublicationThis paper presents a voltammetric analysis of soil. It shows that the voltammetry is a useful method for the assessment of soil contaminated with heavy metal ions. There are two major problems with voltammetry analysis: the diffusion coefficient and the measurement system. The paper contains a short literature study of mathematical equations and a study of differences between soil and water measurements. Suggestions of the solution...
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FEM and experimental investigations of concrete temperature field in the massive stemwall of the bridge abutment
PublicationThe paper deals with the prediction of early-age concrete temperature of cast-in-place stemwall of the bridge abutment. The considered object is an arch bridge located in Gda´nsk. In the case of massive structures, it is particularly important to not exceed the temperature difference between the core and the concrete surface. Too high temperature gradient generates an increase in thermal stresses, what could be the reason of exceeding...
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Assessment of tensile forces in Sopot Forest Opera membrane by in situ measurements and iterative numerical strategy for inverse problem
PublicationAssessment of tensile forces in newly build Sopot Forest Opera roofing membrane is presented. The procedure is based on in situ measurements and solution of the inverse problem by an iterative procedure. The goal of the analysis is to determine whether the stress state of the membrane is consistent with the design assumptions. The paper contains the description of measurements, used instruments, applied loadings, numerical investiga-tions...
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A Method and Device for 3D Recognition of Cutting Edge Micro Geometry
PublicationA very useful method was successfully applied in the investigation of tools for machining wood and wood based composites. It allows scanning of the cutting edge micro geometry in three dimensions and reproducing it in a virtual space as a 3D surface. The application of the method opens new possibilities of studying tool wear by scanning, including the calculation of volume loss and other analysis of tool wedge geometry along and...
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Numerical and experimental investigation of guided ultrasonic wave propagation in non-uniform plates with structural phase variations
PublicationThe article presents the results of numerical and experimental investigations of guided wave propagation in aluminum plates with variable thickness. The shapes of plate surfaces have been specially designed and manufactured using a CNC milling machine. The shapes of the plates were defined by sinusoidal functions varying in phase shift, which forced the changes in thickness variability alongside the propagation path. The main aim...
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Method of lines for Hamilton-Jacobi functional differential equations.
PublicationInitial boundary value problems for nonlinear first order partial functional differential equations are transformed by discretization in space variables into systems of ordinary functional differential equations. A method of quasi linearization is adopted. Suffcient conditions for the convergence of the method of lines and error estimates for approximate solutions are presented. The proof of the stability of the diffrential difference...
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A novel formulation of 3D spectral element for wave propagation in reinforced concrete
PublicationThe paper deals with numerical simulations of wave propagation in reinforced concrete for damage detection purposes. A novel formulation of a 3D spectral element was proposed. The reinforcement modelled as the truss spectral element was embedded in the 3D solid spectral finite element. Numerical simulations have been conducted on cuboid concrete specimens reinforced with two steel bars. Different degradation models were considered...
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Efficient Method for the Synthesis of Functionalized Basic Maleimides
PublicationA three-step procedure involving Diels-Alder condensation of maleic anhydride with furane, formation of N-substituted imide upon reaction with appropriate diamine and a final retro Diels-Alder regeneration of the maleic carbon-carbon double bond is proposed for an unequivocal synthesis of N-substituted basic maleimides. The novel method is characterized by mild reaction conditions, easy work-up, high yields and no need for additional...
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Rational method of grit chamber efficiency determination
PublicationAlthough grot chambers are designed with utmost care, they still remain difficuly to control. As concentration of grit is non-uniform, representative measurements of the sand concentration is a very complex issue. In the paper the results of measure,ents performed at WTP in Gdańsk and Gdynia were analyzed. The proposed method to determine grit chambers efficiency is based on comparison of suspension flow in the inlet and flux of...
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Application of the J-matrix method to multichannel scattering
PublicationIn this contribution we describe the multichannel extension to the nonrelativistic J-matrix method, and present differential cross sections for scattering of slow electrons from Argon atoms. Nonrelativistic phase shifts, then the S-matrix and the cross sections have been calculated using newly developed Fortran code, JMATRIX-MULTI.We applied the model Hartree-Fock potential as the scattering potential, which was truncated in the...
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Uncertainty estimation of loop impedance measurement determined by the vector method
PublicationThis article presents a detailed analysis of uncertainty estimation of loop impedance measurement determined by the vector method. The analysis includes the following estimates: resistance variance, voltage variance and time measurement variance. This paper presents a methodology for estimating the combined standard uncertainty of loop impedance by the vector method. The vector method allows to determine loop impedance based on...
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Pre-swirl energy saving device in marine application
PublicationThis paper covers topics of energy saving device (ESD) with application to marine propulsors. The form of ESD, considered in this paper, consists of fixed lifting foils mounted in front of the screw propeller (the pre-swirl stator/guide vanes). An algorithm for designing propulsion systems, consisting of guide vanes and screw propeller, is presented. The proposed method relies on hybrid lifting line (guide vanes)-lifting surface...
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Determination of the Bending Properties of Wire Rope Used in Cable Barrier Systems
PublicationThis paper presents research on the bending properties of 3 × 7 19-mm wire rope commonly used in road cable barriers. A total of 19 experimental tests were conducted. In addition, two nonlinear 3D numerical models of the wire rope using beam and solid finite elements were developed. Based on these models, four numerical simulations were carried out. The numerical results were validated against the experimental ones and a very good...
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Quaternion Encryption Method for Image and Video Transmission
PublicationQuaternions are hyper-complex numbers of rank 4. They are often applied to mechanics in 3D space and are considered to be one of the best ways of representing rotations. In this paper a quaternion encryption method, based on algorithm by Nagase et al. (2004) has been proposed. According to a computer-based simulation the results of the performed research yield a high level of security, which is additionally strengthened by the...
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Evaluation of the influence of the opening pressure of a marine Diesel engine injector on the results of numerical simulation of the working cycle and their comparison with the results of the laboratory experiment
PublicationThe article presents the results of a numerical simulation of the working process carried out in a diesel engine. In the applied utility program DIESEL-RK, the laboratory engine Farymann Diesel type D10 was implemented. A selected inoperability of its functional fuel supply system - reduced opening pressure of the injector pinj - was introduced. The values of adequate diagnostic parameters were determined: working gas temperature...
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Comparison of Compact Reduced Basis Method with Different Model Order Reduction Techniques
PublicationDifferent strategies suitable to compare the performance of different model order reduction techniques for fast frequency sweep in finite element analysis in Electromagnetics are proposed and studied in this work. A Frobenius norm error measure is used to describe how good job a reduced-order model is doing with respect to the true system response. In addition, the transfer function correct behavior is monitored by studying the...
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A Universal Gains Selection Method for Speed Observers of Induction Machine
PublicationProperties of state observers depend on proper gains selection. Each method of state estimation may require the implementation of specific techniques of finding those gains. The aim of this study is to propose a universal method of automatic gains selection and perform its verification on an induction machine speed observer. The method utilizes a genetic algorithm with fitness function which is directly based on the impulse response...
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Comparison of Absorbed and Intercepted Fractions of PAR for Individual Trees Based on Radiative Transfer Model Simulations
PublicationThe fraction of absorbed photosynthetically active radiation (fAPAR) is a key parameter for estimating the gross primary production (GPP) of trees. For continuous, dense forest canopies, fAPAR, is often equated with the intercepted fraction, fIPAR. This assumption is not valid for individual trees in urban environments or parkland settings where the canopy is sparse and there are well-defined tree crown boundaries. Here, the distinction...
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Application of gpr method in diagnostics of reinforced concrete structures
PublicationThis paper presents an application of the ground penetration method (GPR) for diagnostics of reinforced concrete structures. In situ measurements were conducted for three civil engineering structures: the ground floor structure, the abutment of the railway viaduct and the concrete well. The dual polarized ground penetrating radar with the antenna operating at a center frequency of 2 GHz was used for GPR surveys. Three different...