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Search results for: NUMERICAL MODELING DOUFOURE AND SORRET EFFECT INCLINED MHD NONLINEAR RADIATIONS MICRO MOTILE ORGANISMS NANOFLUID MULTI SLIP CONDITIONS
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A Numerical Model Study on Ice Boom in a Coastal Lake
PublicationA numerical study on the effectiveness of the proposed ice boom to be installed near the entrance of Lake Notoro, Hokkaido, Japan to prevent sea ice moving into the lake is presented. A two-dimensional hydro–ice dynamics model was modified to allow for the treatment of ice-boom interaction with the effect of tidal current. The numerical model is a coupled hydrodynamic and ice dynamic model. The ice dynamic component uses a Lagrangian...
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Oversizing the photovoltaic generator capacity in a micro photovoltaic plant
PublicationA significant part of photovoltaic micro installations in Poland is characterized by photovoltaic generator oversizing in relation to the inverter. The idea of oversizing, however, still raises doubts among some plant owners. In the paper, the energy yield of installation with an oversized and not oversized photovoltaic generator is presented on selected examples, showing the legitimacy of oversizing.
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Two-Stage Variable-Fidelity Modeling of Antennas with Domain Confinement
PublicationSurrogate modeling has become the method of choice in solving an increasing number of antenna design tasks, especially those involving expensive full-wave electromagnetic (EM) simulations. Notwithstanding, the curse of dimensionality considerably affects conventional metamodeling methods, and their capability to efficiently handle nonlinear antenna characteristics over broad ranges of the system parameters is limited. Performance-driven...
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Enhancing Resilience of FSO Networks to Adverse Weather Conditions
PublicationOptical wireless networks realized by means of gigabit optical wireless communication (OWC) systems are becoming, in a variety of applications, an important alternative, or a complementary solution, to their fiber-based counterparts. However, performance of the OWC systems can be considerably degraded in periods of unfavorable weather conditions, such as heavy fog, which temporarily reduce the effective capacity of the network....
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An investigation of structural responses of inverted pavements by numerical approaches considering nonlinear stress-dependent properties of unbound aggregate layer
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Marine propeller shaft bearings under low-speed conditions: water vs. oil lubrication
PublicationThe bearings used in shipbuilding, hydropower, and water pumps have undergone a metamorphosis in recent decades. Because of environmental regulations, lubrication with grease or mineral oil is prohibited. Thus, the standard solutions include water-lubricated bearings with polymer bushings or sealed systems lubricated with oil. When properly designed, assembled, and operated, bearings can operate reliably for years. However, specific...
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Numerical modelling and experimental verification of compressible squeeze film pressure
PublicationThe validity of using the Reynolds equation for compressible squeeze film pressure was tested with computational fluid dynamics (CFD). A squeeze film air bearing was instrumented with pressure sensors and non-contacting displacement probes to provide transient measurements of film thickness and pressure. The film thickness measurements also provided input parameters to the numerical prediction. However, numerical results showed...
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Transportable, Portable and Micro Gas Chromatographs
PublicationSignificant benefits can be obtained by miniaturization of conventional benchtop gas chromatographs. The attractive features arising from miniaturization include low-power requirements, low heat capacity of separation columns, low consumption of mobile phase, enhanced performance, higher portability, and easily coupling to detectors and secondary chromatographic systems. In separation sciences, including gas phase separations,...
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Numerical methods for the assessment of bridge safety barriers
PublicationThe paper presents a numerical study of the bus crash test for bridge safety barriers. The analysis is conducted with the use of explicit code LS-DYNA. The problem of hourglass effect in shell elements is discussed. The simulations of bus impact against the barrier show that the analyzed barrier withstands the impact forces and restrains the bus trajectory to the bridge road.
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Low-Cost Multi-Objective Optimization Yagi-Uda Antenna in Multi-Dimensional Parameter Space
PublicationA surrogate-based technique for fast multi-objective optimization of a multi-parameter planar Yagi-Uda antenna structure is presented. The proposed method utilizes response surface approximation (RSA) models constructed using training samples obtained from evaluation of the low-fidelity antenna model. Utilization of the RSA models allowsfor fast determination of the best possible trade-offs between conflicting objectives in multi-objective...
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Mechanical durability and electroanalytical performance of 3D-printed multi-material sensors
Open Research DataThe data set consists tensile strength, electric resistance, electrochemical characteristics and physicochemical studies of multi-material 3D printed systems, including their sensing performance during detection of antibiotics in an industrial sewage. Additionally, contact angle measurements and SEM micrographs of the electrode surfaces were included.
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Changes in conditions of acoustic wave propagation in the Gdansk deep as an effect of climate changes in the Baltic Sea region
PublicationThe article presents the results from a research project investigating acoustic climate changes in the Gdansk Deep based on data extending from 1902 to 2019. This part of the southern Gotland Basin, is rarely discussed in the scientific literature. The speed of sound in the seawater is a function of temperature, salinity, and depth. In such shallow sea as Baltic Sea, the impact of depth is not substantial. The other two factors...
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Analysis of differences in the stability of proteins encoded in mitochondrial DNA of model organisms
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The influence of cold season warming on the mercury pool in coastal benthic organisms
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Mercury in Living Organisms: Sources and Forms of Occurrence, Bioaccumulation, and Determination Methods
PublicationMercury (Hg) is a heavy metal with well-known and broadly tested toxicity. Since Hg pollution and its impacts on human health are of global concern, it has become necessary to develop analytical methodologies that will provide tools to obtain reliable analytical information about the levels of Hg in samples, which very often have a complex matrix composition. This chapter summarizes key information on Hg and its chemical forms,...
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Nonlinear Interaction of Magnetoacoustic Modes in a Quasi-Isentropic Plasma Flow
PublicationThe nonlinear interaction of magnetoacoustic waves in a plasma is analytically studied. A plasma is an open system. It is affected by the straight constant equilibrium magnetic flux density forming constant angle with the wave vector which varies from 0 till . The nonlinear instantaneous equation which describes excitation of secondary wave modes in the field of intense magnetoacoustic perturbations is derived by use of projecting....
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Numerical analysis of high temperature minichannels heat exchanger performance
PublicationNowadays, the most difficult technological challenge in energy sector is connected with the gas micro-CHP units, dedicated to the distributed power generation. They are expected to be of high efficiency and at the same time of compact in size. Regarding the first reason, significant increase in microturbine efficiency can only be achieved by increase in the engine operating temperature. Therefore, one of the critical elements in...
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Janusz Cieśliński prof. dr hab. inż.
PeopleHe was born on April 15, 1954 in Slupsk. He graduated from the Faculty of Mechanical Engineering at Gdańsk University of Technology (1978). In 1986 he received the title of Doctor, in 1997 he obtained the title of Ph.D. with habilitation, and in 2006 he received the title of Professor. He worked as head of department and vice-dean for Education at the Faculty of Mechanical Engineering for two terms (2002-2008). His research interests...
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Numerical Modelling of Structures with Uncertainties
PublicationThe nature of environmental interactions, as well as large dimensions and complex structure of marine offshore objects, make designing, building and operation of these objects a great challenge. This is the reason why a vast majority of investment cases of this type include structural analysis, performed using scaled laboratory models and complemented by extended computer simulations. The present paper focuses on FEM modelling...
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Multi-state multi-reference Møller-Plesset second-order perturbation theory for molecular calculations
PublicationThis work presents multi‐state multi‐reference Møller–Plesset second‐order perturbation theory as a variant of multi‐reference perturbation theory to treat electron correlation in molecules. An effective Hamiltonian is constructed from the first‐order wave operator to treat several strongly interacting electronic states simultaneously. The wave operator is obtained by solving the generalized Bloch equation within the first‐order...
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Nano-Micro Letters
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Micro and Macro Marketing
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Micro and Nano Engineering
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Micro & Nano Letters
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Balance errors in numerical solutions of shallow water equations
PublicationThe analysis of the conservative properties of the shallow water equations is presented in the paper. The work focuses on the consistency of numerical solution of these equations with the conservation laws of mass and momentum. The investigations involve two different conservative forms which are solved by an implicit box scheme. The theoretical analysis supported by numerical experiments is carried out for rectangular channel...
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Changes in conditions of acoustic wave propagation in the Gdansk deep as an effect of climate changes in the Baltic Sea region
PublicationThe article presents the results from a research project investigating acoustic climate changes in the Gdansk Deepbased on data extending from 1902 to 2019. This part of the southern Gotland Basin, is rarely discussed in thescientific literature.The speed of sound in the seawater is a function of temperature, salinity, and depth. In such shallow sea asBaltic Sea, the impact of depth is not substantial....
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Comparison of experimental and numerical results on metallic plates subjected to explosions
PublicationA 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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Effect of the Climatic Conditions in Central Europe on the Growth and Yield of Cornelian Cherry Cultivars
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The Research into the Effect of Conditions of Combined Electric Powered Diamond Processing on Cutting Power
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The Effect of Welding Conditions on Mechanical Properties of Superduplex Stainless Steel Welded Joints
PublicationThe tests results of superduplex stainless steel welded joints made with a different heat input, using automatic submerged arc welding (SAW) and semi-automatic flux-cored arc welding (FCAW) have been presented. Metallographic examinations, the measurements of the ferrite content, the width of the heat affected zone (HAZ) and the hardness of the welds in characteristic areas have been performed. Significant differences in the amount of...
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Carbon dioxide photoconversion. The effect of titanium dioxide immobilization conditions and photocatalyst type.
PublicationBadanie efektywności procesu fotokonwersji CO2 prowadzono w fazie gazowej w obecności promieniowania UV-Vis, pary wodnej oraz fotokatalizatorów. Zbadano wpływ wybranych parametrów tj. masa, temperatura i czas suszenia fotokatalizatora oraz rodzaj nośnika na efektywność procesu fotokonwersji. Wyznaczono optymalne parametry prowadzenia procesu oraz przedstawiono wstępne wyniki badań w obecności fotokatalizatorów modyfikowanych nanoczastkami...
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Operational Enhancement of Numerical Weather Prediction with Data from Real-time Satellite Images
PublicationNumerical weather prediction (NWP) is a rapidly expanding field of science, which is related to meteorology, remote sensing and computer science. Authors present methods of enhancing WRF EMS (Weather Research and Forecast Environmental Modeling System) weather prediction system using data from satellites equipped with AMSU sensor (Advanced Microwave Sounding Unit). The data is acquired with Department of Geoinformatics’ ground...
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INTERNATIONAL JOURNAL OF NONLINEAR SCIENCES AND NUMERICAL SIMULATION
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The effect of numerical 2D and 3D FEM element modelling on strain and stress distributions at laser weld notches in steel sandwich type panels
PublicationLike other means of transport, merchant ships face the problem of increasing requirements concerning the environment protection, which, among other issues, implies the reduction of fuel consumption by the ship. Here, the conventional approach which consists in making use of higher strength steels to decrease the mass of the ship hull can be complemented by the use of new steel structures of sandwich panel type. However, the lack...
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Discrete-time estimation of nonlinear continuous-time stochastic systems
PublicationIn this paper we consider the problem of state estimation of a dynamic system whose evolution is described by a nonlinear continuous-time stochastic model. We also assume that the system is observed by a sensor in discrete-time moments. To perform state estimation using uncertain discrete-time data, the system model needs to be discretized. We compare two methods of discretization. The first method uses the classical forward Euler...
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An interactive system for remote modeling and design validation of hybrid photovoltaic systems
PublicationAbstract: A multi-functional demonstrator of the interactive system is presented. The demostrator enables modeling, monitoring and design validation of hybrid photovoltaic systems assisted by fuel cells and thermoelectric generators, as well as experimentation and scientific research. A block diagram of the system is presented and the selection of its components is discussed. Availability of the system via Ethernet or GSM...
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Thermal and Hydrodynamic Phenomena in the Stagnation Zone — Impact of the Inlet Turbulence Characteristics on the Numerical Analyses
PublicationOne of the methods of heat transfer enhancement is utilization of the turbulent impinging jets, which were recently applied, for example, in the heat exchangers. Their positive impact on the heat transfer performance was proven, but many questions related to the origin of this impact are still unanswered. In general, the wall-jet interaction and the near-wall turbulence are supposed to be its main reason, but their accurate numerical...
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Nonlinear increase in bubbles radii caused by sound in a bubbly liquid
PublicationThe nonlinear interaction of acoustic and entropy modes in a bubbly liquid is considered. The reasons for interaction are both nonlinearity and dispersion. In the field of intense sound, a decrease in the mixture density is predicted. That corresponds to the well-established growth of bubbles volumes due to rectified diffusion. The nonlinear interaction of modes as a reason for a bubble to grow due to sound, is discovered. The...
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Essentials of micro and macroeconomics - Summer 2024
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Numerical solution of threshold problems in epidemics and population dynamics
PublicationA new algorithm is proposed for the numerical solution of threshold problems in epidemics and population dynamics. These problems are modeled by the delay-differential equations, where the delay function is unknown and has to be determined from the threshold conditions. The new algorithm is based on embedded pair of continuous Runge–Kutta method of order p = 4 and discrete Runge–Kutta method of order q = 3 which is used for the...
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Nonlinear Control of a Doubly Fed Generator Supplied by a Current Source Inverter
PublicationNowadays, wind turbines based on a doubly fed induction generator (DFIG) are a commonly used solution in the wind industry. The standard converter topology used in these systems is the voltage source inverter (VSI). The use of reverse-blocking insulated gate bipolar transistor (RB-IGBT) in the current source inverter topology (CSI), which is an alternative topology, opens new possibilities of control methods. This paper presents...
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A study on application of Smoothed Particle Hydrodynamics to multi-phase flows
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Nonlinear viscoelasticity in Three Dimensional filler reinforced rubber composites and nanocomposites
PublicationThis chapter describes the influence of three-dimensional nanofillers used in elastomers on the nonlinear viscoelastic properties. In particular, this part focuses and investigates the most important three-dimensional nanoparticles, which are used to produce rubber nanocomposites. The rheological and the dynamic mechanical properties of elastomeric polymers, reinforced with spherical nanoparticles, like POSS, titanium dioxide and...
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Patch size setup and performance/cost trade-offs in multi-objective antenna optimization using domain patching technique
PublicationA numerical study concerning multi-objective optimization of antenna structures using sequential domain patching (SDP) technique has been presented. We investigate the effect of various setups of the patch size on the operation of the SDP algorithm and possible trade-offs concerning the quality of the Pareto set found by SDP and the computational cost of the optimization process. Our considerations are illustrated using a UWB monopole...
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Numerical Study of the Impinging Jets Formed by an Injector with Different Nozzle Diameters
Open Research DataThe data set contains the simulation files related to the research paper “Numerical Study of the Impinging Jets Formed by an Injector with Different Nozzle Diameters”, https://doi.org/10.4271/2022-01-1080.
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Application of the X-ray micro computed tomography to the analysis of the structure of polymeric materials
PublicationIn this paper the application of X-ray micro-computed tomography (micro-CT) as a non-destructive testing method of polymeric materials is presented. Increasing applicability of polymers in variedend-use industries such as automotive, building and construction, consumer goods, and packaging is propelling the growth of the global polymer processing market. However, controlling of the polymer structure is one of the most important...
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EVOLUTIONARY MULTI–OBJECTIVE WEATHER ROUTING OF SAILBOATS
PublicationThe paper presents a multi-objective method, which optimises the route of a sailboat. The presented method makes use of an evolutionary multi-objective (EMO) algorithm, which performs the optimisation according to three objective functions: total passage time, a sum of all course alterations made during the voyage and the average angle of heel. The last two of the objective functions reflect the navigator’s and passenger’s comfort,...
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Comparison of Two Nonlinear Predictive Control Algorithms for Dissolved Oxygen Tracking Problem at WWTP
PublicationThe wastewater treatment plant is classified as a complex system, due to its nonlinear dynamics, large uncertainty of disturbance inputs, multiple time scales in the internal process dynamics, and multivariable structure. The aeration process, in turn, is an important and expensive part of wastewater treatment plant operation. All operating parameters of the aeration in biological processes are to be precisely controlled to provide...
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A multi-level risk-based method for safety assessment of ships in critical conditions. Option for preliminary design
PublicationW pracy przedstawiono wybrane informacje na temat metody oceny bezpieczeństwa statków w warunkach krytycznych. Metoda umożliwia wielokryterialne i wieloparametryczne badanie bezpieczeństwa statków, w celu otrzymania wymaganego i optymalnego poziomu bezpieczeństwa. W metodzie wykorzystano podejście do projektowania oparte o ocenę osiągów statku i ocenę ryzyka. Istnieje możliwość dostosowania metody do oceny bezpieczeństwa statku...
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Effect of processing parameters on the cyclic behaviour of aluminium friction stir welded to spark plasma sintered aluminium matrix composites with bimodal micro-and nano-sized reinforcing alumina particles
PublicationUnderstanding the cyclic behaviour of Alumina reinforced Aluminium composites (Al-A2O3) was of critical importance, for their further application in the different industrial sectors. The present study is focussing on the cyclic behaviour of the Al-Alumina nanocomposite produced through the combination of spark plasma sintering (SPS) method and friction stir welding (FSW). The added Alumina with total content of 10% is the combination...