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Wyniki wyszukiwania dla: GRAPHENE FIELD-EFFECT TRANSISTOR, BEHAVIOURAL MODEL, CIRCUIT SIMULATIONS, SENSORS
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Fiber optic microsphere with a ZnO thin film for potential application in a refractive index sensor – theoretical study
PublikacjaOptical fiber sensors of refractive index play an important role in analysis of biological and chemical samples. This work presents a theoretical investigation of spectral response of a fiber optic microsphere with a zinc oxide (ZnO) thin film deposited on the surface and evaluates the prospect of using such a structure for refractive index sensing. A microsphere is fabricated by an optical fiber tapering method on the base of...
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Influence of stirrups in a concrete shell on strengthening reinforced concrete column
PublikacjaTwelve concrete columns, with a 150x150mm square section and three columns with a circular section (d=200mm), are tested to investigate the effect of strengthening by RC jacket. Based on a confined concrete model for axial static loading, an analytical methods, reported in the literature are proposed to predict the behavior of columns with RC jacket. The results support the conception that the effect of strengthening depends...
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Prediction of maximum tensile stress in plain-weave composite laminates with interacting holes via stacked machine learning algorithms: A comparative study
PublikacjaPlain weave composite is a long-lasting type of fabric composite that is stable enough when being handled. Open-hole composites have been widely used in industry, though they have weak structural performance and complex design processes. An extensive number of material/geometry parameters have been utilized for designing these composites, thereby an efficient computational tool is essential for that purpose. Different Machine Learning...
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Performance of extended Lagrangian schemes for molecular dynamics simulations with classical polarizable force fields and density functional theory
PublikacjaIterative energy minimization with the aim of achieving self-consistency is a common feature of Born-Oppenheimer molecular dynamics (BOMD) and classical molecular dynamics with polarizable force fields. In the former, the electronic degrees of freedom are optimized, while the latter often involves an iterative determination of induced point dipoles. The computational effort of the self-consistency procedure can be reduced by re-using...
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Reconstruction of 3D structure of positive corona streamer by local methods
PublikacjaThe computer algorithms were used for reconstruction of streamer 3D structure. We propose the 3D tree structure model of corona discharge streamer composed with nodes and edges between chosen couples of nodes, which enables easy computation of some important parameters ofstreamers. The 3D model can be derived directly from two projection images by global methods like evolutionary searching or particle simulations. In this paper...
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Design space reduction and variable-fidelity EM simulations for feasible Pareto optimization of antennas
PublikacjaA computationally efficient procedure for multi-objective optimization of antenna structures is presented. In our approach, a response surface approximation (RSA) model created from sampled coarse-discretization EM antenna simulations is utilized to yield an initial set of Pareto-optimal designs using a multi-objective evolutionary algorithm. The final Pareto front representation for the high-fidelity model is obtained using surrogate-based...
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Experimental and Numerical Analysis of Air Trapping in a Porous Medium with Coarse Textured Inclusions
PublikacjaThe paper presents a 2D upward infiltration experiment performed on a model porous medium consisting of fine sand background with two inclusions made of coarser sands. The purpose of the experiment was to investigate the effects of structural air trapping, which occurs during infiltration as a result of heterogeneous material structure. The experiment shows that a significant amount of air becomes trapped in each of the inclusions. Numerical...
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Modeling, simulation, and validation of a TB41 crash test of the H2/W5/B concrete vehicle restraint system
PublikacjaThe paper addresses numerical simulations of a concrete vehicle restraint system. The model is described in detail. The advanced material law of the continuous surface cap model was used to analyze the damage locations in concrete barrier segments. The results were validated against the TB41 full-scale crash test. The test was conducted in compliance with European standard EN 1317, and the validation was performed in accordance...
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A novel one-variable first-order shear deformation theory for biaxial buckling of a size-dependent plate based on Eringen’s nonlocal differential law
PublikacjaPurpose – This paper aims to present a new one-variable first-order shear deformation theory (OVFSDT) using nonlocal elasticity concepts for buckling of graphene sheets. Design/methodology/approach – The FSDT had errors in its assumptions owing to the assumption of constant shear stress distribution along the thickness of the plate, even though by using the shear correction factor (SCF), it has been slightly corrected, the errors...
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An improved method for flow boiling heat transfer with account of the reduced pressure effect
PublikacjaIn the paper are presented the results using the authors own model to predict heat transfer coefficient during flow boiling. The model has been tested against a large selection of experimental data to investigate the sensitivity of the in-house developed model. In the work are presented the results of calculations obtained using the semi-empirical model on selected experimental flow boiling data of the refrigerants: R134a, R1234yf,...
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MULTI-CRITERIA MODEL IN MULTIFUNCTIONAL BUILDING SYSTEM DESIGN PROCESS
PublikacjaThe paper presents a multi-criteria approach in multifunctional building system design process. The aim is to develop a theory relative to the engineering system of multifunctional with a mathematical representation defined by a holistic network for the lifecycle of the designed object. The idea of work was to define the structure of a complex system. Background for the presented field is to develop a design strategy for multifunctional...
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Sensorless Control of Polyphase Induction Machines
PublikacjaThe basics of transformations of polyphase systems into orthogonal systems are explained. Vector models of induction machines in orthogonal planes are analysed and multiscalar models for rotor flux and main flux together with stator current are presented. A speed observer based on an extended model of the induction machine for selected variables is applied in the control system for the induction machine. On the basis of the model...
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The Attitude of Polish Entrepreneurs to the Fact of Staging the Mega Sport Event - the Case of Pomeranian SMEs Towards Euro 2012
PublikacjaIn the course of preparations to the 2012 European Football Championship (Euro 2012) many doubts have arisen as to the actual cost-benefit balance affecting the hosting country. The event is accompanied by intense promotion of the agglomeration and the region, especially abroad. In effect, one can anticipate the competitive position of both the region and the businesses operating there to improve. The investigation whether the...
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Activated persulfate and peroxymonosulfate based advanced oxidation processes (AOPs) for antibiotics degradation – A review
PublikacjaSulfate radical AOPs (SR-AOP) were successfully utilized in degradation of antibiotics in water and wastewater treatment. The review discusses details on SR-AOPs mechanisms and applications for antibiotics degradation. The progress in this field was discussed, highlighting the most promising developments and remaining challenges. The applicability of SR-AOPs was summarized revealing the most susceptible and persistent to oxidation...
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Rearrangeability in multicast Clos networks is NP-complete
PublikacjaPrzestrajalność w polach Closa z połączeniami jeden do jeden jest problemem wielomianowym. W pracy pokazano, że w polach z połączeniami jeden do wiele problem ten jest NP zupełny.Three-stage elos networks are commutation networks with circuit switching. So far, graph theory has been very useful tool for solving issues related to these networks with unicast connections. This is so because if elos network is represented as a bipartite...
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The use of spectrometric diagnostics in identification of the technical condition of tribological systems
PublikacjaThe paper presents, as an effect of the analysis of investigation results, a possibility of using the spectrometric diagnostics in the tribological system technical condition supervision arrangement. A model, based on the emission of solid particles in tribological system operation, allows to identify the system technical condition. After the analysis of tests carried out with the use of that model, it has been found that the content...
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Flexural behavior of composite structural insulated panels with magnesium oxide board facings
PublikacjaThe current report is devoted to the flexural analysis of a composite structural insulated panel (CSIP) with magnesium oxide board facings and expanded polystyrene (EPS) core, that was recently introduced to the building industry. An advanced nonlinear FE model was created in the ABAQUS environment, able to simulate the CSIP’s flexural behavior in great detail. An original custom code procedure was developed, which allowed to include...
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Analysis of positioning error and its impact on high frequency properties of differential signal coupler
PublikacjaThis paper presents the analysis of the effect of differential signal coupler positioning accuracy on its high frequency performance parameters for contact-less high speed chip-to-chip data transmission on PCB application. Our considerations are continuation of the previous works on differential signal coupler concept, design methodology and analysis for high speed data transmission monitoring. The theoretical analysis of possible...
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Effect of band gap on power conversion efficiency of single-junction semiconductor photovoltaic cells under white light phosphor-based LED illumination
PublikacjaOn the basis of the detailed balance principle, curves of efficiency limit of single-junction photovoltaic cells at warm and cool white light phosphor-based LED bulbs with luminous efficacy exceeding 100 lm/W have been simulated. The effect of energy band gap and illuminance on the efficiencies at warm and cool light is discussed. The simulations carried out show that maximum power conversion efficiency at 1000 lx reaches 52.0%...
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At the Limits of Criticality-Based Quantum Metrology: Apparent Super-Heisenberg Scaling Revisited
PublikacjaWe address the question of whether the super-Heisenberg scaling for quantum estimation is indeed realizable. We unify the results of two approaches. In the first one, the original system is compared with its copy rotated by the parameter-dependent dynamics. If the parameter is coupled to the one-body part of the Hamiltonian, the precision of its estimation is known to scale at most as N−1 (Heisenberg scaling) in terms of the number...
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On Bayesian Tracking and Prediction of Radar Cross Section
PublikacjaWe consider the problem of Bayesian tracking of radar cross section. The adopted observation model employs the gamma family, which covers all Swerling cases in a unified framework. State dynamics are modeled using a nonstationary autoregressive gamma process. The principal component of the proposed solution is a nontrivial gamma approximation, applied during the time update recursion. The superior performance of the proposed approach...
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High-Resolution Wind Wave Parameters in the Area of the Gulf of Gdańsk During 21 Extreme Storms
PublikacjaThis dataset contains the results of wind-wave parameter modelling in the area of the Gulf of Gdańsk (Southern Baltic). For the simulations, a high resolution SWAN model was used. The dataset consists of the significant wave height, the direction of the wave approaching the shore and the wave period during 21 historical, extreme storms. The storms were selected by an automatic search over the 44-year-long significant wave height...
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Oddziaływania taboru na mosty kolejowe przy zmiennych parametrach ruchu
PublikacjaW pracy poruszono zagadnienia związane z identyfikacją oraz modelowaniem układu dynamicznego most-pojazd ruchomy. Za element szczególnie istotny uznano czynnik obciążający. Opracowano i wdrożono metodykę identyfikacji cech dynamicznych rzeczywistego pojazdu szynowego. Eksperyment badawczy przeprowadzono dla jednostki trakcyjnej EN57, jednak nie ma żadnych ograniczeń w stosowaniu metody dla innego, konwencjonalnego taboru szynowego....
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Active management of equipment cooling in hoteling data centers
PublikacjaHoteling data centers are designated for housing computing and storage units of many, usually small customers, as opposed to traditional data centers supporting own computing and storage resources of a bigger company. One of the services to be provided to consumer’s equipment is cooling. Cooling in data centers is prevalently achieved by circulating air in computer room. Efficient cooling requires delivering cold air from central...
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Skutki zwarć łukowych w średnionapięciowych rozdzielnicach okrętowych z izolacją powietrzną
PublikacjaW artykule scharakteryzowano moc i napięcie łuku, jak również przedstawiono model termodynamiczny służący do obliczania ciśnienia i temperatury gazów w otoczeniu łuku zwarciowego. Przedstawiono przykładowy układ elektrowni okrętowej i zasilania najważniejszych odbiorników na statku do przewozu kontenerów, w tym 600 kontenerów chłodzonych. Na podstawie parametrów prądnic i silników, odbiorników zasilanych z rozdzielnicy głównej...
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Multi-objective optimization of the cavitation generation unit structure of an advanced rotational hydrodynamic cavitation reactor
PublikacjaHydrodynamic cavitation (HC) has been widely considered a promising technique for industrial-scale process intensifications. The effectiveness of HC is determined by the performance of hydrodynamic cavitation reactors (HCRs). The advanced rotational HCRs (ARHCRs) proposed recently have shown superior performance in various applications, while the research on the structural optimization is still absent. The present study, for the...
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Experimental and numerical evaluation of mechanical behaviour of composite structural insulated panels
PublikacjaComposite structural insulated panels (CSIPs) are novel prefabricated elements for structural applications. Panels under consideration are made from glass-fibre reinforced magnesia cement boards as facesheets and expanded polystyrene foam (EPS) as a core. Quasi-static full-scale and model bending tests under monotonic loading were performed to recognize mechanical properties of CSIPs in flexure. In addition, tensile, compressive,...
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Fading Modelling in Dynamic Off-Body Channels
PublikacjaThis paper presents an off-body fading channel model for Body Area Networks. The proposed model, based on both simulations and measurements at 2.45 GHz in a realistic indoor environment, consists of three components: mean path loss, body shadowing, and multipath fading. The first is modelled as a log function of distance, the path loss exponent being in between 0.4 and 1.6. A statistical perspective is taken for the other two components,...
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Fast Multi-Objective Optimization of Narrow-Band Antennas Using RSA Models and Design Space Reduction
PublikacjaComputationally efficient technique for multi-objective design optimization of narrow-band antennas is presented. In our approach, the corrected low-fidelity antenna model (obtained through coarse-discretization EM simulations) is enhanced using frequency scaling and response correction, sampled, and utilized to obtain a fast response surface approximation (RSA) antenna surrogate. The RSA model is constructed in the reduced design space....
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Detection and Direction-of-Arrival Estimation of Weak Spread Spectrum Signals Received with Antenna Array
PublikacjaThis paper presents a method for the joint detection and direction of arrival (DOA) estimation of low probability of detection (LPD) signals. The proposed approach is based on using the antenna array to receive spread-spectrum signals hidden below the noise floor. Array processing exploits the spatial correlation between phase-delayed copies of the signal and allows us to evaluate the parameter used to make the decision about the...
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Model and laboratory simulation of a induction motor for diagnostic purposes
PublikacjaStatistics say that bearings are this part of induction motors which is most susceptible to damage. The equipment employed for bearing diagnostics usually makes use of vibrations as the criterion for technical condition of the bearings. A faulty bearing results in additional motor vibrations. They are reflected in the harmonic content of stator currents. In certain operating conditions the current signal is the sole source of information...
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Numerically efficient algorithm for compact microwave device optimization with flexible sensitivity updating scheme
PublikacjaAn efficient trust-region algorithm with flexible sensitivity updating management scheme for electromagnetic (EM)-driven design optimization of compact microwave components is proposed. During the optimization process, updating of selected columns of the circuit response Jacobian is performed using a rank-one Broyden formula (BF) replacing finite differentiation (FD). The FD update is omitted for directions sufficiently well aligned...
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Simple 60 GHz Switched Beam Antenna for 5G Millimeter-Wave Applications
PublikacjaA new 60 GHz band single-input switched beam antenna is proposed for the fifth-generation (5G) millimeter-wave network applications. The presented design is capable of electronically switching the main beam in two different directions via a proposed microstrip-line-to-slotline single-pole dual-throw (SPDT) switch based on commercially available p-i-n diodes. The antenna is fabricated in a low-cost printed circuit board process...
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Comparative Analysis of Reactive Power Compensation Devices in a Real Electric Substation
PublikacjaA constant worldwide growing load stress over a power system compelled the practice of a reactive power injection to ensure an efficient power network. For this purpose, multiple technologies exist in the knowledge market out of which this paper emphasizes the usage of the flexible alternating current transmission system (FACTS) and presents a comparative study of the static var compensator (SVC) with the static synchronous compensator...
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Karol Grębowski dr inż.
OsobyKarol Grębowski (dr inż.) pracuje jako adiunkt w Katedrze Technicznych Podstaw Projektowania Architektonicznego na Wydziale Architektury Politechniki Gdańskiej. Jego badania naukowe dotyczą zjawisk szybkozmiennych zachodzących podczas drgań konstrukcji budowlanych, obiektów mostowych (trzęsienia ziemi) oraz badania w zakresie metodologii projektowania budynków stanowiących system ochrony pasywnej (SOP) odpornych na uderzenia pojazdów...
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The effect of reduced pressure on carbon dioxide flow boiling heat transfer in minichannels
Publikacja. In the paper presented are the results of the study on the effect of reduced pressure on flow boiling heat transfer data in minichannels as well as conventional ones. That effect renders that most of heat transfer correlations fail to return appropriate results of predictions. Mostly they have been developed for the reduced pressures from the range 0.1-0.3. The special correction has been postulated to the in-house model of flow...
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PARAMETRIC ANALYSIS OF THE EFFICIENCY OF THE COMBINED GAS-STEAM TURBINE UNIT OF A HYBRID CYCLE FOR THE FPSO VESSEL
PublikacjaA thermal diagram of the combined gas‒steam turbine unit of a hybrid cycle, which is an energy complex consisting of a base gas turbine engine with a steam turbine heat recovery circuit and a steam-injected gas turbine operating with overexpansion, is proposed. A mathematical model of a power plant has been developed, taking into consideration the features of thermodynamic processes of simple, binary, and steam-injected...
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Design and experimental validation of a single-stage PV string inverter with optimal number of interleaved buck-boost cells.
PublikacjaIncreasing converter power density is a problem of topical interest. This paper discusses an interleaved approach of the efficiency increase in the buck-boost stage of an inverter with unfolding circuit in terms of losses in semiconductors, output voltage ripples and power density. Main trends in the power converter development are reviewed. A losses model was designed and used for the proposed solution to find an optimal number...
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Excitation of Circularly Polarized Wave via Single-Feed Metasurface-Integrated Compact Antenna for Internet of Things
PublikacjaA compact circularly polarized (CP) quasi-omnidirectional antenna is introduced for internet of things (IoT). The structure consists of two components implemented on FR-4 substrates, and sep-arated by an air gap: one printed with a rectangular patch fed through a matching network, and another with a metasurface and a ground plane. Two different methods for impedance matching are employed. An equivalent circuit model of the antenna...
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Development of a Peptide Derived from Platelet-Derived Growth Factor (PDGF-BB) into a Potential Drug Candidate for the Treatment of Wounds
PublikacjaObjective: This study evaluated the use of novel peptides derived from platelet-derived growth factor (PDGF-BB) as potential wound healing stimulants. One of the compounds (named PDGF2) was subjected for further research after cytotoxicity and proliferation assays on human skin cells. Further investigation included evaluation of: migration and chemotaxis of skin cells, immunological and allergic safety, the transcriptional analyses...
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AN ALTERNATIVE WAY OF DETERMINING MECHANICAL PROPERTIES OF WOOD BY MEASURING CUTTING FORCES
PublikacjaThe cutting force is an energetic effect of splitting material, and might be therefore considered from a point of view of modern fracture mechanics. The dedicated mathematical model developed for description of the wood cutting has been developed here on the base of fracture theory, and includes work of separation (fracture toughness) in addition to the material plasticity and friction. The effect of the cutting edge dullness is...
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Risk Analysis by a Probabilistic Model of the Measurement Process
PublikacjaThe aim of the article is presentation of the testing methodology and results of examination the probabilistic model of the measurement process. The case study concerns the determination of the risk of an incorrect decision in the assessment of the compliance of products by measurement. Measurand is characterized by the generalized Rayleigh distribution. The model of the meas-urement process was tested in parallel mode by six risk...
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Isotope shifts of multipole lines of Pb I and Pb II
PublikacjaStudies of isotope shifts of three multipole lines between levels of the ground configuration 6s26p2 of Pb I, i.e.: 461.9 nm(1S0→3P1), 531.5 nm(1S0→3P2) and 733.2 nm(1D2→3P1), as well as 710.2 nm line (6s26p2P3∕2→6s26p2P1∕2) of Pb II are presented. We determined the isotope shifts between four stable isotopes: 204, 206, 207, 208. By the use of King plot analysis we were able to separate the mass and the field shifts. We found that...
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Particle Image Velocimetry Measurements of Airflow in Electrohydrodynamic Device for Dust Particle Collection
PublikacjaIn this paper the pumping effect of air in the electrohydrodynamic (EHD) device for dust particle collection is presented. To induce an airflow in this EHD device corona discharge was used. The discharge was generated between the one-sided spike electrodes and the plate electrodes. The asymmetric electric field and generated discharge resulted in a unidirectional airflow through the EHD device. The current-voltage characteristics...
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Solvation of ionic liquids based on N-methyl-N-alkyl morpholinium cations in dimethylsulfoxide – volumetric and compressibility studies
PublikacjaThe density and sound velocity of the solutions of ionic liquids based on N-alkyl-N-methyl-morpholinium cations, N-ethyl-N-methylmorpholinium bis(trifluoromethanesulfonyl)imide, N-butyl-N-methylmorpholinium bis(trifluoromethanesulfonyl)imide, N-methyl-N-octyl-morpholinium bis(trifluoromethanesulfonyl)imide and N-decyl-N-methylmorpholinium bis(trifluoromethanesulfonyl)imide in dimethylsulfoxide were measured at T = (298.15 to 318.15)...
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Self-assembly, stability and conductance of amphotericin B channels: bridging the gap between structure and function
PublikacjaAmphotericin B (AmB), one of the most powerful but also toxic drugs used to treat systemic mycoses, is believed to selectively permeabilize fungal cell membranes to ions in a sterol-dependent manner. Unfortunately, the structure of the biologically active AmB channels has long eluded researchers, obstructing the design of safer alternatives. Here, we investigate the structural and thermodynamic aspects of channel formation, stability,...
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Estimation of groundwater recharge in a shallow sandy aquifer using unsaturated zone modeling and water table fluctuation method
PublikacjaQuantification of groundwater recharge is one of the most important issues in hydrogeology, especially in view of the ongoing changes in climate and land use. In this study, we use numerical models of 1D vertical flow in the vadose zone and the water table fluctuation (WTF) analysis to investigate local-scale recharge of a shallow sandy aquifer in the Brda outwash plain in northern Poland. We show that these two methods can be...
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Mechanical properties of Precontraint 1202S coated fabric under biaxial tensile test with different load ratios
PublikacjaThe paper describes a method of laboratory tests necessary for identifying the mechanical properties of polyester coated fabrics named Precontraint 1202S with PVDF surface treatment. Two sets of initial material parameters for dense net model and orthotropic model are specified. Material parameters for Precontraint 1202S coated fabric are specified on the basis of the biaxial tensile tests for different load ratios. In order to...
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SIMULATION MODEL OF ASON/GMPLS ARCHITECTURE
PublikacjaGrowing demands of information society concerned with sophisticated applications could be satisfied by ASON/GMPLS architecture comprehended as Automatically Switched Optical Network (ASON) with Generalized Multi-Protocol Label Switching (GMPLS). The ASON/GMPLS proposition represents the future direction of Next Generation Network (NGN) architecture. Therefore considerable work has to be done to examine this solution. In this aspect...
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Possible effects of the 1984 St. Clair River ice jam on bed changes
PublikacjaThis study examines the possible effect of the record ice jam of 1984 in the St. Clair River on river bed changes and conveyance. Numerical simulations were made to examine the flow and bed shear stresses during the jam formation and release periods. Simulation results indicate that the ice jam in the river did not cause a significant increase in bed shear stress compared to pre- and post-jam open water conditions. The insignificant...
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Numerical Analysis of TB32 Crash Tests for 4-cable Guardrail Barrier System Installed on the Horizontal Convex Curves of Road
PublikacjaHorizontal curves are one of the elements of road infrastructure where statistically a relatively high number of accidents have been reported. In the last ten years in Poland approx. 10% of all road accidents happened on horizontal curves of roads and was responsible for approx. 14% of all fatalities on Polish roads. Thus, this issue is important and requires extensive research and proper road safety treatments. One possible measure...
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Water-lubricated stern tube bearing - experimental and theoretical investigations of thermal effects
PublikacjaThe paper presents research results of thermal phenomena accompanying operation of a water-lubricated stern tube bearing with axial grooves. Experimental tests revealed, that intensity of forced axial flow has strong influence on bush temperature. Numerical simulations focused on investigation of the thermal phenomena under operation of water-lubricated journal bearing showed, that restricted axial flow promotes backflow of the...
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Advanced Lithium-Ion Battery Model for Power System Performance Analysis
PublikacjaThe paper describes a novel approach in battery storage system modelling. Different types of lithium-ion batteries exhibit differences in performance due to the battery anode and cathode materials being the determining factors in the storage system performance. Because of this, the influence of model parameters on the model accuracy can be different for different battery types. These models are used in battery management system...
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Trust-Based Model for the Assessment of the Uncertainty of Measurements in Hybrid IoT Networks
PublikacjaThe aim of this paper is to introduce a NUT model (NUT: network-uncertainty-trust) that aids the decrease of the uncertainty of measurements in autonomous hybrid Internet of Things sensor networks. The problem of uncertainty in such networks is a consequence of various operating conditions and varied quality of measurement nodes, making statistical approach less successful. This paper presents a model for decreasing the uncertainty...
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Design Space Reduction for Expedited Multi-Objective Design Optimization of Antennas in Highly-Dimensional Spaces
PublikacjaA surrogate-based technique for efficient multi-objective antenna optimization is discussed. Our approach exploits response surface approximation (RSA) model constructed from low-fidelity antenna model data (here, obtained through coarse-discretization electromagnetic simulations). The RSA model enables fast determination of the best available trade-offs between conflicting design goals. The cost of RSA model construction for multi-parameter...
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Numerical and quantitative analysis of HIV/AIDS model with modified Atangana-Baleanu in Caputo sense derivative
PublikacjaFractional calculus plays an important role in the development of control strategies, the study of the dynamical transmission of diseases, and some other real-life problems nowadays. The time-fractional HIV/AIDS model is examined using a novel method in this paper. Based on the Atangana-concept Baleanu’s of a derivative in the Caputo sense, the current modified fractional derivative operator uses singular and non-local kernels....
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Hydraulic equations for vortex separators dimensioning
PublikacjaThe paper presents a set of hydraulic expressions developed to design vortex separators. These devices are used for gravitational removal of suspensions from wastewater. Measurements and theoretical considerations allowed the authors to formulate a mathematically simple velocity field model. Than, equations describing particle motion in the separator were derived. Finally, a technical procedure for hydraulic design of vortex separators...
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The analysis of soil resistance during screw displacement pile installation
PublikacjaThe analysis of soil resistances during screw displacement pile installation based on model and field tests. The investigations were carried out as a part of research project, financed by the Polish Ministry of Science and Higher Education. A proposal of empirical method for prediction of rotation resistance (torque) during screw auger penetration in non-cohesive subsoil based on CPT result.
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Measurements of radiation emission of a portable power bank with a capacity of 10400 mAh
Dane BadawczeThe dataset contains the emission measurement results that are part of comprehensive tests carried out for portable power banks with different capacities. The measurements were performed in the frequency range from 30 MHz to 3 GHz using a Gigahertz Transverse Electromagnetic (GTEM) cell (Fig. 1). The test setup was configured to measure a portable power...
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Model Correction and Optimization Framework for Expedited EM-Driven Surrogate-Assisted Design of Compact Antennas
PublikacjaDesign of compact antennas is a numerically challenging process that heavily relies on electromagnetic (EM) simulations and numerical optimization algorithms. For reliability of simulation results, EM models of small radiators often include connectors which—despite being components with fixed dimensions—significantly contribute to evaluation cost. In this letter, a response correction method for antenna models without connector,...
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Hydrological indicators of water zones in inundation, historical water levels, and forcing data for the 1881-2099 period in the lower Biebrza valley
Dane BadawczeThis data set contains hydrological (1) indicators of water source extents in the Biebrza River floodplain (NE Poland) simulated using an integrated hydrological model (IHM), (2) forcing data for the IHM, and (3) water levels in the Osowiec station from the period 1881-1910.
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Towards an efficient multi-stage Riemann solver for nuclear physics simulations
PublikacjaRelativistic numerical hydrodynamics is an important tool in high energy nuclear science. However, such simulations are extremely demanding in terms of computing power. This paper focuses on improving the speed of solving the Riemann problem with the MUSTA-FORCE algorithm by employing the CUDA parallel programming model. We also propose a new approach to 3D finite difference algorithms, which employ a GPU that uses surface memory....
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AC motor feeding cable consequences on EMC performance of ASD
PublikacjaHigh level of conducted EMI emissions of adjustable speed drives (ASD) is one of the most difficult problems in contemporary applications. Many investigations are carried out in order to find more effective methods allowing to predict this emission at early stage of design, and therefore to predict adequate countermeasures. This paper deals with the method which allows to estimate by simulation the influence of motor feeding cable...
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New Complementary Resonator for Permittivity- and Thickness-Based Dielectric Characterization
PublikacjaThe design of high-performance complementary meta-resonators for microwave sensors featur-ing high sensitivity and consistent evaluation of dielectric materials is challenging. This paper presents the design and implementation of a novel complementary resonator with high sensi-tivity for dielectric substrate characterization based on permittivity and thickness. A comple-mentary crossed arrow resonator (CCAR) is proposed and integrated...
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Intelligent monitoring the vertical dynamics of wheeled inspection vehicles
PublikacjaThe problem of intelligent monitoring of the vertical dynamics of wheeled inspection vehicles is addressed. With the independent MacPherson suspension system installed, the basic analysis focuses on the evaluation of the parameters of the so-called quarter car model. To identify a physically motivated continuous description, in practice, dedicated integral-horizontal filters are used. The obtained discrete model, which retains...
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Progressive failure analysis of laminates in the framework of 6-field nonlinear shell theory
PublikacjaThe paper presents the model of progressive failure analysis of laminates incorporated into the 6-field non-linear shell theory with non-symmetrical strain measures of Cosserat type. Such a theory is specially recommended in the analysis of shells with intersections due to its specific kinematics including the so-called drilling rotation. As a consequence of asymmetry of strain measures, modified laminates failure criteria must...
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COMPARISON OF SYSTEM ON CHIP TECHNOLOGIES FOR SPACE APPLICATIONS
PublikacjaThe paper presents a review of technologies available for the implementation of digital and mixed signal systems, particularly the system on a chip (SoC) for space applications. The phenomena encountered in the space environment are briefly presented, together with the known solutions, regarding the design of complex electronic systems. The most important norms regarding single die integrated circuits designed for space are also...
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Symulacje numeryczne jako wsparcie badania właściwości barier ochronnych
PublikacjaArtykuł przedstawia możliwości wykorzystania symulacji numerycznych do badań efektywności urządzeń bezpieczeństwa ruchu drogowego w aspekcie sposobów ich konfgurowania. Obecnie w celu dopuszczenia do stosowania bariery ochronne muszą przejść specjalistyczne testy zderzeniowe. Ze względu na wysoki koszt tych badań coraz częściej producenci barier oraz inne podmioty odpowiadające za urządzenia bezpieczeństwa ruchu drogowego (brd)...
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DETERMINATION OF SEAKEEPING PERFORMANCE FOR A CASE STUDY VESSEL BY THE STRIP THEORY METHOD
PublikacjaThe increase of seakeeping performance is of particular importance for car and passenger ferries, service ships in the gas and oil extraction industry and offshore wind power farm industry, as well as for special purpose ships (including military applications). In the water areas of the Baltic Sea, North Sea, and Mediterranean Sea, which are characterised by a short and steep wave, the hull shape has a substantial impact on the...
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Evaluation of Lombard Speech Models in the Context of Speech in Noise Enhancement
PublikacjaThe Lombard effect is one of the most well-known effects of noise on speech production. Speech with the Lombard effect is more easily recognizable in noisy environments than normal natural speech. Our previous investigations showed that speech synthesis models might retain Lombard-effect characteristics. In this study, we investigate several speech models, such as harmonic, source-filter, and sinusoidal, applied to Lombard speech...
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Wybrane aspekty modelowania matematycznego kolejowego odbieraka prądu
PublikacjaNieprawidłowa współpraca odbieraka z siecią jezdną, w niekorzystnych warunkach lokalnych, prowadzi do uszkodzeń sieci lub odbieraka. Może być to spowodowane niewłaściwym wykonaniem lub utrzymaniem tych istotnych elementów układu zasilania. Tego typu sytuacje awaryjne powodują duże opóźnienia w ruchu pociągów i generują olbrzymie koszty. Wskazuje to na duże znaczenie odpowiednich rozwiązań konstrukcyjnych sieci i odbieraków oraz...
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Experimental research on technical fabric of the Forest Opera Roof in Sopot
PublikacjaThe experimental analysis of the technical fabric Valmex is presented. The study involves uniaxial tensile, cyclic, rheological and biaxial tests. Some of the main differencies between two types of the analysed material have been identified. Mechanical properties of the textile have been modeled by the viscoelastic standard model with quite good effect.
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Durability of Asphalt Concrete Subjected to Deteriorating Effects of Water and Frost
PublikacjaThe paper presents testing of the detrimental effects of water and frost on asphalt pavements. It included laboratory testing of 5 fatigue life of asphalt concrete that was subjected to action of water and frost and field testing of damages caused by water and frost on 6 existing asphalt pavements, such as stripping, raveling, and potholes. Laboratory simulation of water and frost action was based on the 7 original AASHTO T283...
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Distribution of relaxation times as a method of separation and identification of complex processes measured by impedance spectroscopy
PublikacjaImpedance spectroscopy is one of the most commonly performed measurements to characterize electronic and electrochemical systems. Impedance spectra have limited resolution and many different processes may overlap what could be the reason of obstructions in its proper later analysis. Up to date, there are three approaches to solve this problem: examining impedance spectra itself, fitting spectra with equivalent circuits, and calculating...
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Explicit Size-Reduction-Oriented Design of a Compact Microstrip Rat-Race Coupler Using Surrogate-Based Optimization Methods
PublikacjaIn this paper, an explicit size reduction of a compact rat-race coupler implemented in a microstrip technology is considered. The coupler circuit features a simple topology with a densely arranged layout that exploits a combination of high- and low-impedance transmission line sections. All relevant dimensions of the structure are simultaneously optimized in order to explicitly reduce the coupler size while maintaining equal power...
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Fast EM-driven optimization using variable-fidelity EM models and adjoint sensitivities
PublikacjaA robust and computationally efficient technique for microwave design optimization is presented. Our approach exploits variable-fidelity electromagnetic (EM) simulation models and adjoint sensitivities. The low-fidelity EM model correction is realized by means of space mapping (SM). In the optimization process, the SM parameters are optimized together with the design itself, which allows us to keep the number...
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Influence of Flat Lapping Kinematics on Machinability of Ceramics
PublikacjaNew tools for flat grinding of ceramics are presented in the paper. Electroplated CBN tools (B64 and B107) were used in a modified single-disc lapping machine configuration. The results from experiments, such as the material removal rate and surface roughness parameters are presented and analyzed. Numerical simulations, based on the model for the shape error and tool wear estimation in machining with flat lapping kinematics, are...
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Robustified estimators of radar elevation angle using a specular multipath model
PublikacjaWe consider the problem of estimating the elevation angle in the presence of multipath. The proposed method belongs to the class of maximum likelihood-like estimators and employs a modified specular reflection model that accounts for the uncertainty of the steering vector by assuming that they are subject to unknown deterministic perturbations with bounded norms. The analysis, performed using convex optimization methods, allows...
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Simulation of parallel similarity measure computations for large data sets
PublikacjaThe paper presents our approach to implementation of similarity measure for big data analysis in a parallel environment. We describe the algorithm for parallelisation of the computations. We provide results from a real MPI application for computations of similarity measures as well as results achieved with our simulation software. The simulation environment allows us to model parallel systems of various sizes with various components...
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Hydropower potential of the lower Vistula
PublikacjaThis paper presents an estimate analysis of the hydropower potential of the lower Vistula River from Warsaw to Gdańsk Bay. The calculations were made for a hydraulic model of the lower Vistula which takes into account potential development of barrages in a cascade system. Results obtained from the model simulations and from hydrological calculations were used to estimate the power of hydropower plants and the average annual energy...
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Rapid design closure of linear microstrip antenna array apertures using response features
PublikacjaA simple yet reliable approach to a rapid design closure of linear antenna array apertures at the electromagnetic (EM)-simulation level is proposed. Our methodology exploits an underlying array factor (AF) model suitably corrected by means of characteristic points (angles and levels) of the radiation pattern of the EM model of the antenna array aperture. This conveniently allows for controlling both the side lobe levels...
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Large deformation modelling of CPT probing in soft soil—pore water pressure analysis
PublikacjaThis paper presents the results of finite element modelling with Updated Lagrangian formulation of the Cone Penetration Test in soft soil deposit located in Jazowa, Poland. The numerical calculations are carried out for homogenous, normally consolidated, organic soil layer. The Modified Cam Clay constitutive model for soft soil and Coulomb model for interface are used. The study compares the registered pore water pressure distributions...
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Modelling of Longitudinal Elastic Wave Propagation in a Steel Rod Using the Discrete Element Method
PublikacjaThe paper deals with the issue of modelling elastic wave propagation using the discrete element method (DEM). The case of a longitudinal wave in a rod with a circular cross-section was considered. A novel, complex algorithm consisting of the preparation of models and simulation of elastic waves was developed. A series of DEM models were prepared for simulations, differing in discretisation and material parameters. Additional calculations...
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The effect of elevated temperature on LCF damage growth in 2024AA – Experiment and modeling
PublikacjaThis paper presents the results of experimental low-cycle fatigue (LCF) tests conducted on EN-AW 2024 alloy in T3511 temper at 100 ◦C, 200 ◦C and 300 ◦C. The material’s basic fatigue characteristics were determined, such as fatigue life curve and cyclic strain curve. Both the hysteresis loop and nature of fracture surfaces obtained in macro- and microscopic observations (scanning electron microscope, SEM) were accounted for. The...
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Static electric multipole susceptibilities of the relativistic hydrogenlike atom in the ground state: Application of the Sturmian expansion of the generalized Dirac-Coulomb Green function
PublikacjaThe ground state of the Dirac one-electron atom, placed in a weak, static electric field of definite $2^{L}$ polarity, is studied within the framework of the first-order perturbation theory. The Sturmian expansion of the generalized Dirac-Coulomb Green function [R. Szmytkowski, J. Phys. B: At. Mol. Opt. Phys. 30, 825 (1997); erratum R. Szmytkowski, J. Phys. B: At. Mol. Opt. Phys. 30, 2747 (1997)] is used to derive closed-form analytical...
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Modelowanie dynamiki odbieraka prądu pojazdu kolejowego do celów diagnostycznych
PublikacjaNiewłaściwa współpraca odbieraka prądu i sieci trakcyjnej, w trudnych warunkach lokalnych, może prowadzić do uszkodzenia sieci trakcyjnej i pantografu. W ramach rozwoju metod monitoringu i diagnostyki dla tych podsystemów, tworzone są nowe i dokładniejsze narzędzia symulacyjne, których zakres obejmuje modelowanie zarówno napowietrznej sieci trakcyjnej i pantografu, a także ich dynamicznego oddziaływania. Głównym celem jest dokładniejsza...
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Robustness in Compressed Neural Networks for Object Detection
PublikacjaModel compression techniques allow to significantly reduce the computational cost associated with data processing by deep neural networks with only a minor decrease in average accuracy. Simultaneously, reducing the model size may have a large effect on noisy cases or objects belonging to less frequent classes. It is a crucial problem from the perspective of the models' safety, especially for object detection in the autonomous driving...
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Rotor-Flux Vector based Observer of Interior Permanent Synchronous Machine
PublikacjaThe sensorless control system of the interior permanent magnet machine is considered in this paper. The control system is based on classical linear controllers. In the machine, there occurs non-sinusoidal distribution of rotor flux together with the slot harmonics, which are treated as the control system disturbances. In this case, the classical observer structure in the (d-q) is unstable for the low range of rotor speed resulting...
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Analysis of Positioning Error and Its Impact on High Frequency Performance Parameters of Differential Signal Coupler of Differential Signal Coupler
PublikacjaThis paper presents the analysis of the effect of differential signal coupler positioning accuracy on its high frequency performance parameters for contact-less high speed chip-to-chip data transmission on PCB application. Our considerations are continuation of the previous works on differential signal coupler concept, design methodology and analysis for high speed data transmission monitoring presented in [1, 2]. The theoretical...
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Response of a fiber-optic Fabry-Pérot interferometer to refractive index and absorption changes – modelling and experiments
PublikacjaThis paper describes how the refractive index and the absorption of investigated substances change the spectrum of the optical radiation at the output of the fiber-optic Fabry-Pérot interferometer. The modeling of the operation of the interferometer takes into account not only the spectra of the refractive index and the absorption of the medium that is inside the cavity, but also spectra of the refractive indices of the core and...
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THE CONCEPT OF MODELING OF SNOW IMPACT ON THE STRUCTURE OF THE SUSPENDED TAURON ARENA ROOF IN CRACOW
PublikacjaThe article presents studies and numerical simulations on modeling snow influence on TAURON ARENA suspended roof structure in Cracow. The scope of work includes experimental tests, functions solutions taking into account various cases of snow impact according to PN and EC, as well as numerical simulations for the sport and entertainment arena in the Czyzyny district. The FEM roof structure model developed in the SOFISITK software...
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Rapid multi-objective antenna design using point-by-point Pareto set identification and local surrogate models
PublikacjaAntenna design is inherently a multicriterial problem.Determination of the best possible tradeoffs between conflicting objectives (a so-called Pareto front), such as reflection response, gain, and antenna size, is indispensable from the designer’s point of view, yet challenging when high-fidelity electromagnetic (EM) simulations are utilized for performance evaluation. Here, a novel and computationally...
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Safety issues referred to induced sheath voltages in high-voltage power cables – case study
PublikacjaLoad currents and short-circuit currents in high-voltage power cable lines are sources of the induced voltages in the power cables’ concentric metallic sheaths. When power cables operate with single-point bonding, which is the simplest bonding arrangement, these induced voltages may introduce an electric shock hazard or may lead to damage of the cables’ outer non-metallic sheaths at the unearthed end of the power cable line. To...
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Running characteristics of aerodynamic bearing with self-lifting capability at low rotational speed
PublikacjaAn aerodynamic journal bearing that is capable of self-generating squeeze-film pressure is presented and its dynamic characteristics investigated numerically and experimentally. A numerical method based on a time marching static model was applied to assess the orbit trajectory path of the rotor upon a perturbation. Experimental results were obtained to validate the effect of the self- generated squeeze-film pressure on the stability...
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Antenna Modeling Using Variable-Fidelity EM Simulations and Constrained Co-Kriging
PublikacjaUtilization of fast surrogate models has become a viable alternative to direct handling of fullwave electromagnetic (EM) simulations in EM-driven design. Their purpose is to alleviate the difficulties related to high computational cost of multiple simulations required by the common numerical procedures such as parametric optimization or uncertainty quantification. Yet, conventional data-driven (or approximation) modeling techniques...
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Finite-difference time-domain analyses of active cloaking for electrically-large objects
PublikacjaInvisibility cloaking devices constitute a unique and potentially disruptive technology, but only if they can work over broad bandwidths for electrically-large objects. So far, the only known scheme that allows for broadband scattering cancellation from an electrically-large object is based on an active implementation where electric and magnetic sources are deployed over a surface surrounding the object, but whose ‘switching on’...
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The use of a two-phase Monte Carlo material model to reflect the dispersion of asphalt concrete fracture parameters
PublikacjaThe work covers comprehensive laboratory tests of semi-circular bending (SCB) of asphalt concrete samples. The results of two test series, including four and 32 SCB specimens, indicate a substantial scatter of force–deflection (F-d) histories. The numerical analysis is aimed to reflect the maximum breaking load and fracture energy of the samples, pointing out their random character. The original simulation-based fictitious Monte...
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Bridge Non-Destructive Measurements Using a Laser Scanning during Acceptance Testing: Case Study
PublikacjaOwing to the recent proliferation of inventory works on roads and railways, bridge acceptance tests have increased exponentially. These tests’ results are often misinterpreted owing to the use of various measuring equipment types, rendering integrated interpretation problematic. It is also problematic that adjusting the measurement method is difficult when the structure’s response to load is uncertain. Therefore, it is important...
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On Alternative Approaches to Design of Corporate Feeds for Low-Sidelobe Microstrip Linear Arrays
PublikacjaTwo design approaches, illustrated by simulations and measurements, aiming at a systematic computer-aided design of printed circuit feeds for low-sidelobe microstrip antenna arrays are described. The novelty of these approaches resides in identification of the optimal feed architectures with subsequent simulation-based optimization of the feed and array aperture dimensions. In this work, we consider microstrip corporate feeds realizing...
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Fatigue life prediction of notched components under size effect using strain energy reformulated critical distance theory
PublikacjaNotch and size effects show significant impact on the fatigue performance of engineering components, which deserves special attention. In this work, a strain energy reformulated critical distance theory was developed for fatigue life prediction of notched components under size effect. Experimental data of different notched specimens manufactured from GH4169, TC4, TC11 alloys and low carbon steel En3B were used for model validation...