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Numerical solution analysis of fractional point kinetics and heat exchange in nuclear reactor
PublicationThe paper presents the neutron point kinetics and heat exchange models for the nuclear reactor. The models consist of a nonlinear system of fractional ordinary differential and algebraic equations. Two numerical algorithms are used to solve them. The first algorithm is application of discrete Grünwald-Letnikov definition of the fractional derivative in the model. The second involves building an analog scheme in the FOMCON Toolbox...
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Particle Shape Effect on Macroscopic Behaviour of Underground Structures: Numerical and Experimental Study
PublicationAbstract: The mechanical performance of underground flexible structures such as buried pipes or culverts made of plastics depend not only on the properties of the structure, but also on the material surrounding it. Flexible drains can deflect by 30% with the joints staying tight, or even invert. Large deformations of the structure are difficult to model in the framework of Finite Element Method, but straightforward in Discrete...
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Numerical Analysis of Impact of Energy Buoy Anchoring Configurations on its Motion and Efficiency
PublicationThis paper presents a numerical analysis of the impact of energy buoy mooring configurations on its movement on the wave and effectiveness. The method used to analyse the buoy movement modelling in six degrees of freedom was described in a paper presented at the Conference 2011. Simulations of the buoy movement in regular wave and power calculations were conducted for several configurations of anchoring systems and position of...
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Response of high voltage disconnector under seismic excitation - experimental and numerical study
PublicationThe efficiency of the energetic infrastructure system is a very import safety issue in the region experienced by the ground motion. The aim of the present paper is to show the results of the experimental and numerical study focused on the earthquake-induced response of the high voltage disconnector, which is an important element of energetic network. First, the impact tests as well as the sweep-sine shaking table tests were conducted....
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Experimental Validation of Numerical Model within a Flow Configuration of the Model Kaplan Turbine
PublicationThis paper investigates validation of flow within a model Kaplan turbine. This includes comparison of various turbulence models and their influence on torque and power generated by the turbine. Numerical results were compared with experimental data.
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Space-Time Conservation Method applied to numerical solution of water hammer equations
PublicationArtykuł poświęcony jest metodzie czasoprzestrzennych objętości skończonych (STC) zastosowanej do przypadku uderzenia hydraulicznego w stalowym przewodzie pracującym pod ciśnieniem. Metoda STC ze względu na swoje własności numeryczne - m.in. wysoką dokładność - może być interesującą alternatywą dla tradycyjnych metod numerycznych, szczególnie w przypadku, gdy efekty numeryczne mają bardzo silny wpływ na rozwiązanie, tym samym utrudniając...
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Influence of anisotropic stiffness in numerical analyses of tunneling and excavation problems in stiff soils
PublicationIn the stiff overconsolidated soil deposits anisotropy influences small and intermediate strain stiffness and hence it has important impact on the results of discplacement preditcions in soil-structure modelling. The authors developed a cross-anisotropic soil model which combines both stress dependent and micro-structural anisotropy. The model is based on the anisotropic hyperelastic kernel for small strain stiffness. Reference...
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Experimental and numerical studies of guided wave damage detection in bars with structural discontinuities
PublicationPraca dotyczy analizy propagacji fal podłużnych i poprzecznych w elementach prętowych z nieciągłościami strukturalnymi. Symulacje numeryczne przeprowadzone przy zastosowaniu metody elementów spektralnych zostały porównane z wynikami badań eksperymentalnych dla pręta w stanie nienaruszonym oraz dla prętów z rysą, spawem oraz dodatkową masą.
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Numerical Analysis of Magnetic Core Properties Influence on Residual Current Device Behaviour
PublicationW artykule przedstawiono analizę wpływu kształtu prądu w uzwojeniu pierwotnym transformatora prądowego na pracę przekładnika różnicowo-prądowego. Przeprowadzono obliczenia symulacyjne dla wymuszenia o kształcie sinusoidy i sinusoidy wyprostowanej dla częstotliwości 50 Hz. Wzięto pod uwagę dwa typy charakterystyki magnesowania transformatora: dla materiału magnetycznie miękkiego i materiału o prostokątnej pętli histerezy. Analiza...
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Application of extended Finite Element Method to cracked concrete elements - numerical aspects
PublicationArtykuł omawia zastosowanie rozszerzonej metody elementów skończonych do zarysowanych elementów betonowych. Obliczenia wykonano dla elementów poddanych zginaniu i mieszanemu ściskaniu - rozciąganiu. Wyniki porównano z doświadczeniami.
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New Generation of Water lubricated Foil bearing - Numerical Models and Experimental Verification
PublicationIn the paper a new idea of foil water lubricated bearing and methodology of hydrodynamic characteristics calculations is presented. To assesses the theoretical characteristics of these bearings two different computer models were built. First is structural model coupled with fluid model. It takes into account: fluid flow in the deformed fluid gap, specific design of bearing support and friction in bearing support. The second is...
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VALUATION OF EMBEDDED OPTIONS IN NON-MARKETABLE CALLABLE BONDS: A NEW NUMERICAL APPROACH
PublicationThe issue of how to price options embedded in callable bonds has attracted a lot of interest over the years. The usual bond valuation methods rely on yield curves, risk premium, and other parameters to estimate interest rates used in discounted cash flow calculations. The option to retire the bond is, however, neglected in the standard pricing models, causing a systematic overvaluation of callable bonds. In the event of a decline...
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Experimental-Numerical Analysis of the Effect of Bar Diameter on Bond in Pull-Out Test
PublicationBar diameter is one of the basic factors affecting bond behavior, which is still of interest due to opposing opinions regarding its effect on bond behavior in the pull-out test. This paper presents an experimental and numerical bond analysis of ribbed reinforcing bar in concrete. The aim was to experimentally evaluate the effect of bar diameter on the bond behavior in the pull-out test and to perform numerical simulations of the...
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Numerical analysis of lumbar spine injury during road safety barrier collision
PublicationPurpose: Enhancing road safety is a critical goal worldwide, necessitating the development of clear standards for road safety systems. This study focuses on lumbar spine (L-spine) compression injuries during collisions with concrete road safety barriers (RSBs). It aims to analyze internal forces during impact to understand L-spine injury biomechanics in such accidents. Methods: The research included a literature review, analyzing...
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Advanced numerical modelling for predicting residual compressive strength of corroded stiffened plates
PublicationAn advanced methodology for predicting the residual compressive strength of corroded stiffened plates is developed here using the non-linear finite element method. The non-uniform loss of a plate thickness is accounted for on a macro-scale. In contrast, mechanical properties are changed using the constitutive model to reflect the corrosion degradation impact on a micro-scale. Three different stiffened plate thicknesses are considered,...
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Experimental and Numerical Study on Mechanical Characteristics of Aluminum/Glass Fiber Composite Laminates
PublicationThe fiber-metal composites made of aluminum sheets and glass fibers reinforced with a polyester resin as the matrix were studied. The composites were prepared by hand lay-up method. Some aspects of manufacturing affecting the composite behavior were considered. In particular, the influences of the arrangement of layers and their number on the mechanical and physical properties of composites with ten different compositions were...
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Numerical investigation of multiphase blood flow coupled with lumped parameter model of outflow
PublicationPurpose The purpose of this paper is the application of the computational fluid dynamics model simulating the blood flow within the aorta of an eight-year-old patient with Coarctation of Aorta. Design/methodology/approach The numerical model, based on commercial code ANSYS Fluent, was built using the multifluid Euler–Euler approach with the interaction between the phases described by the kinetic theory of granular flow (KTGF). Findings A...
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Numerical Analysis of Turbulent Flow over a Backward-facing Step in an Open Channel
PublicationComputational examinations of the flow field in an open channel having a single Backward--Facing Step (BFS) with a constant water depth of 1.5 m were performed. The effects of the expansion ratio, and the flow velocity along the reattachment length, were investigated by employing two different expansion ratios of 1.5 and 2, and eight various flow velocities of 0.5, 1, 2, 3, 4, 5, 7.5 and 10 m/sec in the Computational Fluid Dynamic...
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Numerical study on seismic response of a base-isolated building modelled with shell elements
PublicationSeismic isolation is counted among the most popular and effective means of protecting structures against earthquake forces. Base isolators, like Lead-Rubber Bearings (LRB), High-Damping Rubber Bearings (HDB) or Friction Pendulum Systems (FPS) are extensively used in practice in many earthquake-prone regions of the world. The present paper reports the results obtained from the numerical study on seismic response of a base-isolated...
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Diagnosis of Damage in a Steel Tank with Self-Supported Roof through Numerical Analysis
PublicationThe safety of civil engineering structures is one of the most important issues of building industry. That is why the assessment of the damage-involved structural response has recently become of major concern to engineers. Among a number of different approaches to diagnosis of damage, the method of measuring the changes in natural frequencies is considered to be one of the most effective indicators of global damage. From the practical...
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Historical carpentry corner log joints—Numerical analysis within stochastic framework
PublicationThe paper presents the results of numerical analysis performed on historical, traditional carpentry corner logjoints of two basic topologies: the short-corner dovetail connection and the saddle notch connection. These types of carpentry joints are commonly used in currently preserved objects of wooden architecture. All connections have been modelled in pinewood, which has been defined in the Finite Element software MSC.Marc/Mentat...
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Composite Sandwich Footbridge – Numerical ESL FEM Calculations vs. In Situ Measurements
PublicationSelected results of the static analysis of composite sandwich footbridge with the corresponding in situ measured values are compared in the paper. The analysed bridge is a research object, which was built in 2015 and is currently located at the Gdańsk University of Technology campus. Since it is a novel structure, a proper definition of the bridge numerical model, allowing its safe design, is very important. Therefore, instead...
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Particle Shape Effect on Macroscopic Behaviour of Underground Structures: Numerical and Experimental Study
PublicationThe mechanical performance of underground flexible structures such as buried pipes or culverts made of plastics depend not only on the properties of the structure, but also the material surrounding it. Flexible drains can deflect by 30% with the joints staying tight, or even invert. Large deformations of the structure are difficult to model in the framework of Finite Element Method, but straightforward in Discrete Element Methods....
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Minichannel and minigap classification criteria based on the aspect ratio of the minigeometry: A numerical study
PublicationA detailed numerical investigation has been carried out to analyze the diabatic flow distribution and velocity profile in 18 minigeometries with various aspect ratios for V-type and I-type flow configurations (for 36 cases) assuming ethanol as a working fluid. The aim of the study is to distinguish the value of the aspect ratio for which the flow in minigeometry starts to be two-dimensional (minigap). Cases with a constant Reynolds...
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Numerical analysis of the container vessel's self-propulsion at different rudder deflection angles
PublicationNowadays, CFD becomes one of the most commonly used research method in ship hydrodynamics, limited to the analyses of hull resistance in calm water. With continuously improving computing power and increasingly more accurate numerical methods it is possible to simulate more complex cases. State of the art CFD tools also enable development of new ways of assessing ship maneuvering performance. This paper presents an attempt on using...
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Experimental and numerical analysis of the modified TB32 crash tests of the cable barrier system
PublicationRoad restraint systems, including safety barriers, are one of the means used to improve road safety. Currently, they can be allowed to general use after passing the specific crash tests. However, it is always important and desirable to evaluate their performance under various realistic conditions, which can happen on the roads. In this study, the behaviour of the cable barrier system in impact conditions different than assumed...
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Stability Assessment of Coastal Cliffs Incorporating Laser Scanning Technology and a Numerical Analysis
PublicationWe investigated the cli coast in Jastrzebia Gora, Poland. The measurements that were taken between 2014 and 2018 by applying terrestrial, mobile, and airborne laser scanning describe a huge geometric modification involving dislocations in a 2.5 m range. Dierential maps and a volumetric change analysis made it possible to identify the most deformed cli’s location. Part of the monitoring of coastal change involved the measurement...
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Heat transfer intensification by jet impingement – numerical analysis using RANS approach
PublicationJet impingement is a method of the heat transfer enhancement applied in the engineering systems. The idea is to generate fast-flow fluid jet which impinge on the heated (or cooled) surface, causing significantly higher heat transfer rate. Although some flat surface jet impingement cases are described in the literature, the validated data is still limited. The reason is coming from the fact, that these flows are hydrodynamically...
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Numerical Analysis of Recharge Rates and Contaminant Travel Time in Layered Unsaturated Soils
PublicationThis study focused on the estimation of groundwater recharge rates and travel time of conservative contaminants between ground surface and aquifer. Numerical simulations of transient water flow and solute transport were performed using the SWAP computer program for 10 layered soil profiles, composed of materials ranging from gravel to clay. In particular, sensitivity of the results to the thickness and position of weakly permeable...
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Comparison of AHP and Numerical Taxonomy Methods Based on Biogas Plant Location Analysis
PublicationThe paper presents a comparison of the multi-criteria Analytic Hierarchy Process (AHP) method and numerical taxonomy in biogas plant location selection. Biogas plants are sources that will significantly contribute to the implementation of the provisions of the energy and climate package for Poland by 2030. Increasing the share of energy produced from renewable sources, e.g. biogas plants, will increase the country’s energy security....
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Modelling and Measurement of Folk Guitar: Truss Rod and Strings in Numerical Analysis of Tone
PublicationThe study makes an attempt to model a complete vibrating guitar including its non-linear features, specifically the tension-compression of truss rod and tension of strings. The purpose of such a model is to examine the influence of design parameters on tone. Most experimental studies are flawed by uncertainties introduced by materials and assembly of an instrument. Since numerical modelling of instruments allows for deterministic...
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Comparative Analysis of Numerical and Experimental Studies of the Airflow Around the Sample of Urban Development
PublicationIn this paper, on the background of a short overview of the recent advances in the field of Environmental Wind Engineering (EWE), a comparison of wind tunnel experiment and numerical simulation for some cases of airflow around an urban layout have been reported. The purpose of the study is quantitative and qualitative comparison of measurements in the wind tunnel as well as numerical simulation using Ansys Fluent software. The...
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On Nonlinear Bending Study of a Piezo-Flexomagnetic Nanobeam Based on an Analytical-Numerical Solution
PublicationAmong 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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Effect of Flow Normalization in Micro-Pin-Finned Heat Sink: Numerical Study
PublicationThe micro-pin-fin heat sink (MPFHS) is widely employed for the heat transfer enhancement of microchannel heat sinks. In the current paper, the effect of flow normalization on the thermohydraulic performance of micro-pin-finned heat sinks is studied numerically. Two geometries of MPFHSs, the conventional design micro-pin-fin heat sink (CD-MPFHS) with a uniform-width micro pin fin and the proposed design micro-pin-fin heat sink (PD-MPFHS)...
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Experimental and numerical investigations of ultimate strength of imperfect stiffened plates of different slenderness
PublicationThe objective of this study is to analyse the behaviour of compressed stiffened plates of different slenderness using experimental and numerical methods. The presented results are part of a long-term project to investigate the ultimate strength of geometrically imperfect structures subjected to different degradation phenomena, including corrosion degradation and locked cracks. Several specimens were subjected to a uniaxial compressive...
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Experimental and Numerical Investigation of Mechanical Properties of Lightweight Concretes (LWCs) with Various Aggregates
PublicationHigh requirements for the properties of construction materials and activities directed at environment protection are reasons to look for new solutions in concrete technology. This research was directed at solutions affecting the reduction of energy consumption and CO2 emissions. The use of lightweight concretes (LWCs) allows one to meet both conditions at the same time. The purpose of the research presented in this paper was to...
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Experimental and Numerical Investigation of Tensile and Flexural Behavior of Nanoclay Wood-Plastic Composite
PublicationIn this study, the effect of wood powder and nanoclay particle content on composites’ mechanical behavior made with polyethylene matrix has been investigated. The wood flour as a reinforcer made of wood powder was at levels of 30, 40, and 50 wt.%, and additional reinforcement with nanoclay at 0, 1, 3, and 5 wt.%. Furthermore, to make a composite matrix, high-density polyethylene was used at levels of 70, 60, and 50% by weight....
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Numerical analysis of high temperature minichannel heat exchanger for recuperative microturbine system
PublicationConsidering the development of energy sector, distributed small-scale power generation, e.g., gas micro-CHP, is attracting considerable interest. In such installations, the heat exchanger is one of the key components possessing a significant influence on overall performance. Most studies concentrate on units operating below 900C, which do not fulfil the requirements of gas micro-CHP. Therefore, there remains a challenge to design...
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On numerical analysis of a thin-walled I-beam with warping stiffenes undertorsional loads
PublicationPraca jest streszczeniem referatu wygłoszonego na międzynarodowej konferencji Metody Komputerowe w Mechanice, Wisła, 3-6 czerwca 2003. Przedstawiono problem numerycznej analizy belek cienkościennych ze stężeniami. Omówiono dwa modele jednowymiarowe: jeden bazujący na koncepcji skupionej sztywności bimomentowej, a drugi na zastosowaniu superelementu MES. Otrzymane wyniki porównano z rezultatami analizy MES przy zastosowaniu dyskretyzacji...
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Numerical analysis of a test embankment on soft ground using an anisotropic model with destructuration
PublicationPrzeprowadzono analizę numeryczną konsolidacji podłoża słabonośnego pod obciążeniem próbnego nasypu drogowego metodą elementów skończonych. Zachowanie się gruntu słabonośnego zamodelowano przy użyciu nowego modelu konstytutywnego typu multi-laminate uwzględniającego anizotropię wytrzymałości oraz zjawisko destrukturyzacji. Wyniki obliczeń porównano z pomiarami polowymi.
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Some remarks about numerical stability in nonlinear dynamics on the basic of truss structures.
Publication.
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The computer numerical control system with permanent magnet synchronous motor servo-drives.
PublicationPrzedstawiono układ serwonapędów wieloosiowej maszyny sterowanej numerycznie. W układzie wykorzystano silniki synchroniczne z magnesami trwałymi oraz procesory synałowe DSP. Omówiono algorytmy sterowania nadrzędnego oraz problemy sterownia silnika PMSM.
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Numerical calculation of three-phase transformer's residual flux in ATP and PSpice programs.
PublicationW artykule przedstawiono analizę przebiegów prądu i strumienia magnetycznego podczas wyłączania transformatora energetycznego, wykonaną w celu określenia strumieni szczątkowych. Wykorzystano do tego celu modele obwodowe zbudowane w oparciu o programy symulacyjne ATP (Alternative Transients Program) i PSpice. Wyniki obliczeń okazały się bardzo zbliżone dla obu modeli. Przy ich wykorzystaniu obliczono strumienie szczątkowe w kolumnach...
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Statistical description and numerical calculations of cylindrical vertical tanks with initial geometric imperfections
PublicationDokonano identyfikacji rzeczywistych wstępnych imperfekcji geometrycznych stalowych pionowych zbiorników walcowych. Imperfekcje przedstawiono jako pole losowe opisane za pomocą odpowiednio dobranej funkcji korelacyjnej, wartości oczekiwanej oraz obwiedni pola. Wykorzystując własne programy numeryczne przeprowadzono generację zbioru odchyłek geometrycznych zbiornika. Porównano estymatory wygenerowanego pola losowego z parametrami...
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Numerical method of lines for first order partial differential equations with deviated variables
PublicationPraca traktuje o przybliżaniu rozwiązań klasycznych równańróżniczkowo-funkcyjnych cząstkowych pierwszego rzędu rozwiązaniamiukładów quasiliniowych równań różnicowych. Nowe podejście dorozwiązywania równań nieliniowych zawdzięczamy metodziequasilinearyzacji dla zagadnień początkowo - brzegowych z odchylonymargumentem. Dla przyrostów pochodnych funkcji danej zakładamy nieliniowe oszacowanie typu Perrona. Załączone są wyniki eksperymentów...
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Experimental and numerical investigations on RC beams with stirrups scaled along height or length.
PublicationBelki żelbetowe (RC) ze zbrojeniem poprzecznym (strzemiona) poddane czteropunktowemu zginaniu zostały zbadane eksperymentalnie i numerycznie. Belki były skalowane wzdłuż wysokości lub długości. Były przezbrojone, aby uniknąć płynięcia zbrojenia podłużnego. W pierwszej kolejności przeprowadzono badania laboratoryjne na belkach żelbetowych ze strzemionami. Ze względu na brak podobieństwa geometrycznego zaobserwowano dwa odrębne tryby...
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Numerical investigations of effect of indoor air quality on thermal comfort in residential buildings.
PublicationArtykuł przedstawia wyniki numeryczne MES odnośnie wpływu koncentracji CO2 w lokalnej strefie powietrza w budynkach mieszkalnych naturalnie wentylowanych na zachowanie mieszkańców. Obliczenia wykonano w 2 wymiarach. Zbadano wpływ położenia mieszkańców i prędkości wchodzącego powietrza.
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An facile Fortran-95 algorithm to simulate complex instabilities in three-dimensional hyperbolic systems
Open Research DataIt is well know that the simulation of fractional systems is a difficult task from all points of view. In particular, the computer implementation of numerical algorithms to simulate fractional systems of partial differential equations in three dimensions is a hard task which has no been solved satisfactorily. Here, we provide a Fortran-95 code to solve...
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Dataset of phase portraits of the fractional prey-predator model with Holling type-II interaction (without predator harvesting)
Open Research DataThe need for a fractional generalization of a given classical model is often due to new behaviors which cannot be taken into account by the model. In this situation, it can be useful to look for a fractional deformation of the initial system, trying to fit the fractional exponent of differentiation in order to catch properly the data.
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INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS
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