wyświetlamy 1000 najlepszych wyników Pomoc
Wyniki wyszukiwania dla: MODEL-ORDER REDUCTION, A POSTERIORI ERROR ESTIMATOR, FINITE ELEMENT METHOD.
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Test of the antimicrobial properties against E. coli of the innovative CS-2b preservative.
Dane BadawczeThe dataset contains the results of a single series of determinations of the antimicrobial properties against E. coli of the innovative CS-2 b preservative in the solution of model fluids.During the test, the infected product is inoculated (on chromogenic Coliform Agar) at specified intervals (0 min. [cs2b 0] and after 1 day-24 h of incubation [cs2b...
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Test of the antimicrobial properties against Listeria monocytogenes of the innovative CS-2a preservative.
Dane BadawczeThe dataset contains the results of a single series of determinations of the antimicrobial properties against Listeria monocytogenes of the innovative CS-2 a preservative in the solution of model fluids.During the test, the infected product is inoculated (on Oxford Agar) at specified intervals (0 min. [Listeria cs2a 0] and after 1 day-24 h of incubation...
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FPGA computation of magnitude of complex numbers using modified CORDIC algorithm
PublikacjaIn this work we present computation of the magnitude of complex numbers using a modified version of the CORDIC algorithm that uses only five iterations. The relationship between the computation error and the number of CORDIC iterations are presented for floating-point and integer arithmetics. The proposed modification of CORDIC for integer arithmetic relies upon the introduction of correction once basic computations are performed...
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Heavy duty vehicle fuel consumption modelling using artificial neural networks
PublikacjaIn this paper an artificial neural network (ANN) approach to modelling fuel consumption of heavy duty vehicles is presented. The proposed method uses easy accessible data collected via CAN bus of the truck. As a benchmark a conventional method, which is based on polynomial regression model, is used. The fuel consumption is measured in two different tests, performed by using a unique test bench to apply the load to the engine. Firstly,...
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A study of a reduction of a micro- and nanometric bismuth oxide in hydrogen atmosphere
PublikacjaA reduction of bismuth oxide in hydrogen atmosphere was investigated. The reaction was performed with a material in various structural forms: powder: with micrometric grains, powder with nanometric grains and powder pressed into pellets. The process was performed in both isothermal and non-isothermal conditions. An activation energy of the reaction calculated with Friedman method was found to be about 85 kJ/mol for the reduction...
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Quasi-analytical Near-to-Far Field Transformation Based on Field Matching Method for Scattering Problems
PublikacjaA new quasi-analytical near-to-far field transformation based on field matching method (field expansion in a base of Hankel functions) is presented. This approach uses finite element method to obtain near field, then the field is expressed in a base of Hankel functions. The evaluated coefficients allow to calculate the field outside the numerical domain, also in a far distance. The main advantage of the proposed technique is avoiding of...
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Soil-structure interaction effects on modal parameters of office buildings with different number of stories
PublikacjaThe paper summarizes the results of a numerical investigation designed to study the soil-structure interaction effects on modal parameters of three office buildings. The reinforced-concrete 4-storey, 8-storey, and 12-storey office buildings, each with additional two levels of embedded basements, represent low, medium, and high-rise structures, respectively. In order to conduct this research, detailed finite-element structure models...
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Hybrid model of moving or rotating continua
PublikacjaThe paper introduces the method of the model reduction of systems that experience a Coriolis acceleration or gyroscopic effect component. In such causes that corresponding system equations are non-self-adjoined. Modal reduced model is built up for the system without Coriolis or gyroscopic effect terms. These phenomena are next included by application of any lumping technique. Hence, the final reduced model is a hybrid one, obtained...
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The Design of Cavity Resonators and Microwave Filters Applying Shape Deformation Techniques
PublikacjaThis article introduces shape deformation as a new approach to the computer-aided design (CAD) of high-frequency components. We show that geometry deformation opens up new design possibilities and offers additional degrees of freedom in the 3-D modeling of microwave structures. Such design flexibility is highly desirable if the full potential of additive manufacturing (AM) is to be exploited in the fabrication of RF and microwave...
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Akaike's final prediction error criterion revisited
PublikacjaWhen local identification of a nonstationary ARX system is carried out, two important decisions must be taken. First, one should decide upon the number of estimated parameters, i.e., on the model order. Second, one should choose the appropriate estimation bandwidth, related to the (effective) number of input-output data samples that will be used for identification/ tracking purposes. Failure to make the right decisions results...
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Szacowanie estymaty menzurandu temperatury skóry człowieka podczas próby wysiłkowej
PublikacjaW artykule zaprezentowano wyniki pomiarów temperatury skóry człowieka podczas próby wysiłkowej. Ponieważ uzyskane wyniki nie podlegają rozkładowi normalnemu, wyznaczono wartości pięciu różnych estymatorów menzurandu. Otrzymane rezultaty wykazały, że w rozważanym przypadku najlepszy estymator menzurandu otrzymujemy z metody bootstrap, ponieważ charakteryzuje się on najmniejszym odchyleniem standardowym.
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Comparison of experimental and numerical results on metallic plates subjected to explosions
PublikacjaA comparative study of dynamic response including damage and rupture processes of thin metallic plates subjected to shockwave impulses - explosions is presented. The results of the finite element numerical analysis are related to experiments. Due to high strain rate during explosions the elasto-viscoplastic Chaboches constitutive law including damage effects has been applied. For the assumed model proper material parameters identification...
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Numerical tests of time-stepping schemes in the context of FEM for 6-field shell dynamics
PublikacjaThe paper deals with integration of dynamic equations of irregular shells performed with relatively long time steps. Numerical instability appearing often in this kind of analysis motivated the authors to present some studies based on numerical tests referring to convergence problems of finite element analysis as well the applied stability conditions. The analysis is carried out on simulations of shell dynamics with the where the...
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On Nonlinear Bending Study of a Piezo-Flexomagnetic Nanobeam Based on an Analytical-Numerical Solution
PublikacjaAmong various magneto-elastic phenomena, flexomagnetic (FM) coupling can be defined as a dependence between strain gradient and magnetic polarization and, contrariwise, elastic strain and magnetic field gradient. This feature is a higher-order one than piezomagnetic, which is the magnetic response to strain. At the nanoscale, where large strain gradients are expected, the FM effect is significant and could be even dominant. In...
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Iterative‐recursive estimation of parameters of regression models with resistance to outliers on practical examples
PublikacjaHere, identification of processes and systems in the sense of the least sum of absolute values is taken into consideration. The respective absolute value estimators are recognised as exceptionally insensitive to large measurement faults or other defects in the processed data, whereas the classical least squares procedure appears to be completely impractical for processing the data contaminated with such parasitic distortions. Since...
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Monte Carlo simulations of the fracture resistance degradation of asphalt concrete subjected to environmental factors
PublikacjaThe paper presents the results of laboratory tests of SCB (semi-circular beam) samples of asphalt concrete, subjected to the destructive effect of water and frost as well as the aging processes. The determined values of material parameters show significant dispersions, which makes the design of mixtures difficult. Statistical analysis of the test results supplemented by computer simulations made with the use of the proprietary...
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Anna Sobieraj-Żłobińska dr inż.
OsobyAnna Sobieraj-Żłobińska (ur. 1977 w Przasnyszu) ukończyła Liceum Ogólnokształcące im. Komisji Edukacji Narodowej w Przasnyszu. Od 1996 kontynuowała naukę na Wydziale Geodezji i Gospodarki Przestrzennej na Akademii Rolniczo-Technicznej im. Michała Oczapowskiego w Olsztynie. W 2001 zdobyła tytuł magistra inżyniera na Uniwersytecie Warmińsko-Mazurskim w Olsztynie (temat pracy dyplomowej „Określenie modelu regresji wielokrotnej do...
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One-dimensional chaos in a system with dry friction: analytical approach
PublikacjaWe introduce a new analytical method, which allows to find chaotic regimes in non-smooth dynamical systems. A simple mechanical system consisting of a mass and a dry friction element is considered. The corresponding mathematical model is being studied. We show that the considered dynamical system is a skew product over a piecewise smooth mapping of a segment (the so-called base map). For this base map we demonstrate existence of...
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Regression points in non-intrusive polynomial chaos expansion method and D-optimal design
PublikacjaThe paper addresses selected issues of uncertainty quantification in the modelling of a system containing surgical mesh used in ventral hernia repair. Uncertainties in the models occur e.g. due to variability of abdominal wall properties among others. In order to include them, a non-intrusive regression-based polynomial chaos expansion method is employed. Its accuracy depends on the choice of regression points. In the study a relation...
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Topological-numerical analysis of a two-dimensional discrete neuron model
PublikacjaWe conduct computer-assisted analysis of a two-dimensional model of a neuron introduced by Chialvo in 1995 [Chaos, Solitons Fractals 5, 461–479]. We apply the method of rigorous analysis of global dynamics based on a set-oriented topological approach, introduced by Arai et al. in 2009 [SIAM J. Appl. Dyn. Syst. 8, 757–789] and improved and expanded afterward. Additionally, we introduce a new algorithm to analyze the return times...
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Recurrence times in the Morse sets for a two-dimensional discrete neuron model (low resolution)
Dane BadawczeThis dataset contains selected results of rigorous numerical computations conducted in the framework of the research described in the paper “Topological-numerical analysis of a two-dimensional discrete neuron model” by Paweł Pilarczyk, Justyna Signerska-Rynkowska and Grzegorz Graff. A preprint of this paper is available at https://doi.org/10.48550/arXiv.2209.03443.
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Estimation of the Regenerative Braking Process Efficiency in Electric Vehicles
PublikacjaIn electric and hybrid vehicles, it is possible to recover energy from the braking process and reuse it to drive the vehicle using the batteries installed on-board. In the conditions of city traffic, the energy dissipated in the braking process constitutes a very large share of the total resistance to vehicle motion. Efficient use of the energy from the braking process enables a significant reduction of fuel and electricity consumption...
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Medially positioned plate in first metatarsophalangeal joint arthrodesis
PublikacjaObjective The purpose of this study was to biomechanically compare the stability of first metatarsophalangeal (MTP1) joint arthrodesis with dorsally and medially positioned plates. Methods A physical model of the MTP1 joint consists of printed synthetic bones, a titanium locking plate and screws. In the experiments, samples with dorsally and medially positioned plates were subjected to loading of ground load character in a universal...
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Modal analysis of cylindrical steel tanks
PublikacjaCylindrical steel tanks are very popular structures used for storage of products of chemical and petroleum industries. Their safety and reliability is crucial because any failure could have serious consequences. The aim of present paper is to show the results of the first phase of investigation of seismic behaviour such structures. Modal analysis using Finite Element Method (FEM) for three models of real tanks used in Poland has...
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ESTIMATION OF YOUNG`S MODULUS OF THE POROUS TITANIUM ALLOY WITH THE USE OF FEM PACKAGE
PublikacjaPorous structures made of metal or biopolymers with a structure similar in shape and mechanical properties to human bone can easily be produced by stereolithographic techniques, e.g. selective laser melting (SLM). Numerical methods, like Finite Element Method (FEM) have great potential in testing new scaffold designs, according to their mechanical properties before manufacturing, i.e. strength or stiffness. An example of such designs...
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Suppression of distortions in signals received from Doppler sensor for vehicle speed measurement
PublikacjaDoppler sensors are commonly used for movement detection and speed measurement. However, electromagnetic interference and imperfections in sensor construction result in degradation of the signal to noise ratio. As a result, detection of signals reflected from moving objects becomes problematic. The paper proposes an algorithm for reduction of distortions and noise in the signal received from a simple, dual-channel type of a Doppler...
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A Numerical Study on Baseline-Free Damage Detection Using Frequency Steerable Acoustic Transducers
PublikacjaIn structural health monitoring (SHM) a considerable amount of damage detection algorithms based on guided waves (GW) have been developed. Most of them rely on extensive transducer networks, besides preliminary reference measurements of the structures. This originated a growing demand for hardware simplification and cost reduction of the wave-based SHM methods, driving the conception of new solutions enabling both: the reduction...
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Long-term hindcast simulation of water temperature and salinity in the Baltic Sea
Dane BadawczeThe dataset contains the results of numerical modelling of water temperature and salinity over a period of 50 years (1958-2007) in the Baltic Sea. A long-term hindcast simulation was performed using a three-dimensional hydrodynamic model PM3D (Kowalewski and Kowalewska-Kalkowska, 2017), a new version of the M3D model (Kowalewski, 1997). The hydrodynamic...
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SHORT REVIEW AND 3-D FEM ANALYSIS OF BASIC TYPES OF FOUNDATION FOR OFFSHORE WIND TURBINES
PublikacjaSome problems of the foundations of offshore wind turbines are considered in this paper. A short review is presented on the two basic types of foundations, i.e. monopiles and gravity foundations, including their basic features and applications as well as general design considerations. Also, some issues regarding analysis are discussed, including geotechnical problems and modelling techniques. A numerical model of offshores turbine...
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Biomimetic torene shells
PublikacjaThe genome inside the eukaryotic cells is guarded by a unique shell structure, called the nuclear envelope (NE), made of lipid membranes. This structure has an ultra torus topology with thousands of torus-shaped holes that imparts the structure a high flexural stiffness. Inspired from this biological design, here we present a novel ‘‘torene’’ architecture to design lightweight shell structures with ultra-stiffness for engineering...
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A Computationally Efficient Model for Predicting Successful Memory Encoding Using Machine-Learning-based EEG Channel Selection
PublikacjaComputational cost is an important consideration for memory encoding prediction models that use data from dozens of implanted electrodes. We propose a method to reduce computational expense by selecting a subset of all the electrodes to build the prediction model. The electrodes were selected based on their likelihood of measuring brain activity useful for predicting memory encoding better than chance (in terms of AUC). A logistic...
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Process engineering in circular economy
Kursy OnlineDefinition and principles of the circular economy (CE). The transition from a linear model to a circular model. Business models for the CE. Circular design and innovation. CE assessment carbon footprint, life cycle assessment. Case studies of the cities implementing the CE concept. CE policy and legislation (EU and Poland). Wastewater treatment plants as an element of the CE. Energy and nutrient recovery technologies in wastewater...
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Anharmonic Infrared Spectroscopy through the Fourier Transform of Time Correlation Function Formalism in ONETEP
PublikacjaDensity functional theory molecular dynamics (DFT-MD) provides an efficient framework for accurately computing several types of spectra. The major benefit of DFTMD approaches lies in the ability to naturally take into account the effects of temperature and anharmonicity, without having to introduce any ad hoc or a posteriori corrections. Consequently, computational spectroscopy based on DFT-MD approaches plays a pivotal role in...
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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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Mechanism of Solute and Thermal Characteristics in a Casson Hybrid Nanofluid Based with Ethylene Glycol Influenced by Soret and Dufour Effects
PublikacjaThis article models a system of partial differential equations (PDEs) for the thermal and solute characteristics under gradients (concentration and temperature) in the magnetohydrodynamic flow of Casson liquid in a Darcy porous medium. The modelled problems are highly non-linear with convective boundary conditions. These problems are solved numerically with a finite element approach under a tolerance of 10−8. A numerical algorithm...
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Mathematical and numerical modelling,W,IDE-EMSS,IIst,sem.01,lato,2023/24 (PG_00057379)
Kursy OnlineModelling of controlled mechanical systems by the mixed method of rigid and flexible finite elements: The finite element volume problems. Dynamics of multibody systems. Modelling of stationary closed loop systems. Modelling of systems whose configuration changes with time. Modelling of nonlinear controlled systems. Optimal control at energy performance index: Control of continuous nonstationary systems in domain of generalised...
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Mathematical and Numerical Modelling, L, IDE IInd, sem.01, summer, 2022/23(00057379)
Kursy OnlineModelling of controlled mechanical systems by the mixed method of rigid and flexible finite elements: The finite element volume problems. Dynamics of multibody systems. Modelling of stationary closed loop systems. Modelling of systems whose configuration changes with time. Modelling of nonlinear controlled systems. Optimal control at energy performance index: Control of continuous nonstationary systems in domain of generalised...
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Tensile validation tests with failure criteria comparison for various GFRP laminates
PublikacjaThe paper studies the mechanical properties of glass fibre reinforced polymers (GFRP) with various types and orientation of reinforcement. Analyzed specimens manufactured in the infusion process are made of polymer vinyl ester resin reinforced with glass fibres. Several samples were examined containing different plies and various fibres orientation [0, 90] or [+45, –45]. To assess the mechanical parameters of laminates, a series...
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Adhesive compliance effect in mode I separation:Profilometry approach
PublikacjaThe effect of adhesive compliance on the deflection of a loaded, bonded beam was studied using laser profilometry. Experimental data obtained were compared with both Euler-Bernoulli (encastré) and Winkler (one parameter elastic foundation) models. A third, analytical, 2D model, based on shear within the adhesive layer (two parameter elastic foundation), was introduced. Finite element analysis (FEA) was also used to study the effect...
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Piotr Skurski prof. dr hab.
OsobyPiotr Stanisław Skurski (ur. 25 sierpnia 1969 w Gdańsku) – polski chemik specjalizujący się w chemii kwantowej i fizycznej, profesor nauk chemicznych, profesor zwyczajny Wydziału Chemii Uniwersytetu Gdańskiego, kierownik Katedry Chemii Teoretycznej i Pracowni Chemii Kwantowej na tym wydziale, a także Professor of Chemistry w Henry Eyring Center for Theoretical Chemistry na Uniwersytecie Utah w Stanach Zjednoczonych. W latach 2011-2016 członek...
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Online sound restoration system for digital library applications
PublikacjaAudio signal processing algorithms were introduced to the new online non-commercial service for audio restoration intended to enhance the content of digitized audio repositories. Missing or distorted audio samples are predicted using neural networks and a specific implementation of the Jannsen interpolation method based on the autoregressive model (AR) combined with the iterative restoring of missing signal samples. Since the distortion...
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Simulations of hydro-fracking in rock mass at meso-scale using fully coupled DEM/CFD approach
PublikacjaThe paper deals with two-dimensional (2D) numerical modelling of hydro-fracking (hydraulic fracturing) in rocks at the meso-scale. A numerical model was developed to characterize the properties of fluid-driven fractures in rocks by combining the discrete element method (DEM) with computational fluid dynamics (CFD). The mechanical behaviour of the rock matrix was simulated with DEM and the behaviour of the fracturing fluid flow...
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A Method for The Assessing of Reliability Characteristics Relevant to an Assumed Position-Fixing Accuracy in Navigational Positioning Systems
PublikacjaThis paper presents a method which makes it possible to determine reliability characteristics of navigational positioning systems, relevant to an assumed value of permissible error in position fixing. The method allows to calculate: availability , reliability as well as operation continuity of position fixing system for an assumed, determined on the basis of formal requirements - both worldwide and national, position-fixing accuracy....
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Marek Zienkiewicz dr inż.
OsobyDoktor inżynier Marek Hubert dwojga imion Zienkiewicz jest absolwentem Wydziału Geodezji, Inżynierii Przestrzennej i Budownictwa Uniwersytetu Warmińsko-Mazurskiego w Olsztynie. Zainteresowania naukowe w okresie studiów inżynierskich, magisterskich i doktoranckich rozwijał pod opieką przedstawicieli olsztyńskiej szkoły geodezyjnego rachunku wyrównawczego. W roku 2011 uzyskał tytuł zawodowy magistra inżyniera w zakresie geodezji...
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The influence of the grid density of measurement points on damage detection in an isotropic plate by the use of elastic waves and laser scanning Doppler vibrometry
PublikacjaDamage detection in structural components, especially in mechanical engineering, is an 2 important element of engineering practice. There are many methods of damage detection, in which 3 changes in various parameters caused by the presence of damage are analysed. Recently, methods 4 based on the analysis of changes in dynamic parameters of structures, i.e. frequencies or mode shapes 5 of natural vibrations, as well as changes in...
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A MODEL FOR FORECASTING PM10 LEVELS WITH THE USE OF ARTIFICIAL NEURAL NETWORKS
PublikacjaThis work presents a method of forecasting the level of PM10 with the use of artificial neural networks. Current level of particulate matter and meteorological data was taken into account in the construction of the model (checked the correlation of each variable and the future level of PM10), and unidirectional networks were used to implement it due to their ease of learning. Then, the configuration of the network (built on the...
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THE INTERACTION BETWEEN STEEL COLUMN CHORD AND CLOSELY SPACED REINFORCEMENT.
PublikacjaNowadays, more often than before, civil engineering designers are willing to use steel build-up members composed of single or doubled cold-formed chords interconnected using different mechanical connectors. This paper subject is an analysis of cooperation of a closely spaced built-up cold-formed chord interconnected with series of bolts that are located along the length of the member in a specific spacing. This distance along the...
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Significant Production of Thermal Energy in Partially Ionized Hyperbolic Tangent Material Based on Ternary Hybrid Nanomaterials
PublikacjaNanoparticles are frequently used to enhance the thermal performance of numerous materials. This study has many practical applications for activities that have to minimize losses of energy due to several impacts. This study investigates the inclusion of ternary hybrid nanoparticles in a partially ionized hyperbolic tangent liquid passed over a stretched melting surface. The fluid motion equation is presented by considering the...
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Sensitivity analysis in design process of sandwich U-shaped composite footbridge
PublikacjaThe structure of the sandwich composite footbridge of a 14 metre span length and U-shaped cross-section was analysed. Sensitivity analysis was performed to support the design process of this innovative object. Linear discrete sensitivity analysis was performed by means of finite element method. The influence of vari-ation of several design variables i.e. thicknesses of inner and outer laminates on the mid-span deflection, as-sumed...
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A Parallax Shift Effect Correction Based on Cloud Height for Geostationary Satellites and Radar Observations
PublikacjaThe effect of cloud parallax shift occurs in satellite imaging, particularly for high angles of satellite observations. This study demonstrates new methods of parallax effect correction for clouds observed by geostationary satellites. The analytical method that could be found in literature, namely the Vicente et al./Koenig method, is presented at the beginning. It approximates a cloud position using an ellipsoid with semi-axes...