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Recent Advances in Performance-Driven Surrogate Modeling of High-Frequency Structures
PublikacjaDesign of high‐frequency structures, including microwave and antenna components, heavily relies on full‐wave electromagnetic (EM) simulation models. Their reliability comes at a price of a considerable computational cost. This may lead to practical issues whenever numerous EM analyses are to be executed, e.g., in the case of parametric optimization. The difficulties entailed by massive simulations may be mitigated by the use of...
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Cost‐efficient performance‐driven modelling of multi‐band antennas by variable‐fidelity electromagnetic simulations and customized space mapping
PublikacjaElectromagnetic (EM) simulations have become an indispensable tool in the design of contemporary antennas. EM‐driven tasks, for example, parametric optimization, entail considerable computational efforts, which may be reduced by employing surrogate models. Yet, data‐driven modelling of antenna characteristics is largely hindered by the curse of dimensionality. This may be addressed using the recently reported domain‐confinement...
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Rapid tolerance‐aware design of miniaturized microwave passives by means of confined‐domain surrogates
PublikacjaThe effects of uncertainties, primarily manufacturing tolerances but also incomplete information about operating conditions or material parameters, can be detrimental to the performance of microwave components. Quantification of such effects is essential to ensure a meaningful evaluation of the structure, in particular, its reliability under imperfect fabrication procedures. The improvement of the circuit robustness can be achieved...
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Variable‐fidelity modeling of antenna input characteristics using domain confinement and two‐stage Gaussian process regression surrogates
PublikacjaThe major bottleneck of electromagnetic (EM)-driven antenna design is the high CPU cost of massive simulations required by parametric optimization, uncertainty quantification, or robust design procedures. Fast surrogate models may be employed to mitigate this issue to a certain extent. Unfortunately, the curse of dimensionality is a serious limiting factor, hindering the construction of conventional data-driven models valid over...
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Kriging metamodels and design re‐utilization for fast parameter tuning of antenna structures
PublikacjaThe paper addresses the problem of computationally efficient electromagnetic (EM)‐driven design closure of antenna structures. The foundations of the presented approach are fast kriging interpolation metamodels, utilized for two purposes: (a) producing a good starting point for further parameter tuning, and (b) yielding a reasonable Jacobian matrix estimate to jump‐start the optimization procedure. The models are rendered using...
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Editorial for the special issue on advances in forward and inverse surrogate modeling for high-frequency design
PublikacjaThe design of modern‐day high‐frequency devices and circuits, including microwave/RF, antenna and photonic components, historically has relied on full‐wave electromagnetic (EM) simulation tools. Initially used for design verification, EM simulations are nowadays used in the design process itself, for example, for finding optimum values of geometry and/or material parameters of the structures of interest. In a growing number of...
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Low-cost multi-criterial design optimization of compact microwave passives using constrained surrogates and dimensionality reduction
PublikacjaDesign of contemporary microwave circuits is a challenging task. Typically, it has to take into account several performance requirements and constraints. The design objectives are often conflicting and their simultaneous improvement may not be possible; instead, compromise solutions are to be sought. Representative examples are miniaturized microwave passives where reduction of the circuit size has a detrimental effect on its electrical...
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Size reduction of ultra-wideband antennas with efficiency and matching constraints
PublikacjaAntenna design is a multifaceted task that involves handling of various performance figures concerning both electrical performance of the structure as well as its geometry. Simultaneous control of several objectives through rigorous optimization is very challenging and virtually impossible through conventional approaches such as parameter sweeping. In this work, we investigate size reduction of ultra‐wideband antenna structures...
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EM‐driven constrained miniaturization of antennas using adaptive in‐band reflection acceptance threshold
PublikacjaNumerical optimization of geometry parameters is a critical stage of the design process of compact antennas. It is also challenging because size reduction is constrained by the necessity of fulfilling imposed electrical performance requirements. Furthermore, full‐wave electromagnetic (EM) analysis needs to be used for reliable performance evaluation of the antenna structure, which is computationally expensive. In this paper, an...
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A bisection‐based heuristic for rapid EM‐driven multiobjective design of compact impedance transformers
PublikacjaDesign of microwave structures is a multiobjective task where several conflicting requirements have to be considered at the same time. For contemporary circuits characterized by complex geometries, multiobjective optimization cannot be performed using standard population‐based algorithms due to high cost of electromagnetic (EM) evaluations. In this work, we propose a deterministic approach for fast EM‐driven multiobjective design...
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A Novel Trust-Region-Based Algorithm with Flexible Jacobian Updates for Expedited Optimization of High-Frequency Structures
PublikacjaSimulation-driven design closure is mandatory in the design of contemporary high-frequency components. It aims at improving the selected performance figures through adjustment of the structure’s geometry (and/or material) parameters. The computational cost of this process when employing numerical optimization is often prohibitively high, which is a strong motivation for the development of more efficient methods. This is especially...
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Rapid redesign of multiband antennas with respect to operating conditions and material parameters of substrate
PublikacjaThis work addresses geometry parameter scaling of multi-band antennas for Internet of Things applications. The presented approach is comprehensive and permits re-design of the structure with respect to both the operating frequencies and material parameters of the dielectric substrate. A two-step procedure is developed with the initial design obtained from an inverse surrogate model constructed using a set of appropriately prepared...
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Electrical properties of nanostructures in lead-silicate glasses and nanocomposites doped with iron oxide
Dane BadawczeElectrical properties of iron oxide nanostructures observed in silicate glasses and glass-ceramics were studied. Two different sets of glass samples were prepared. The first group of samples has the composition of (50 − 0.5x)SiO2–(50 − 0.5x)PbO– xFe2O3, where x = 15, 20 and 25 (in mol%). Composition of the second group was 50SiO2–(50−x)PbO–xFe2O3, where...
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The XRD diffraction patterns of (La0.3Sr0.6Ce0.1)0.9FexTi(1-x)O3-δ (x=0.1, 0.2 and 0.3) materials after reduction at 900 deg.C in hydrogen
Dane BadawczeThe (La0.3Sr0.6Ce0.1)0.9FexTi(1-x)O3-δ (x=0.1, 0.2 and 0.3) materials were synthesized via the Pechini method. First, the reagents in the form of nitrates were weighed and dissolved in DI water. In another beaker, a stoichiometric amount of titanium (IV) butoxide (Ti(OBu)4) was mixed together with reagent-grade ethylene glycol (EG), and citric acid...
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Magnetic properties of of lead-silicate glasses and nanocomposites doped with iron oxide
Dane BadawczeMagnetic properties of iron-doped glasses and glass-ceramics were studied. Two different sets of glass samples were prepared. The first group of samples has the composition of (50 − 0.5x)SiO2–(50 − 0.5x)PbO– xFe2O3, where x = 15 and 20 (in mol%). Composition of the second group was 50SiO2–(50−x)PbO–xFe2O3, where x=15, 20 and 25 (in mol%). All sampleswere...
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AFM analysis of duplex steel structure and composition
Dane BadawczeDue to the high content of alloying elements, duplex stainless steels are characterized by a complex structure of phase transitions. Among all types of intermetallic compounds, the sigma phase is of major interest due to its detrimental effect on both mechanical properties and corrosion behavior. It is an intermetallic phase enriched in Cr and Mo and...
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Promising Nanoparticle-Based Heat Transfer Fluids—Environmental and Techno-Economic Analysis Compared to Conventional Fluids
PublikacjaProviding optimal operating conditions is one of the major challenges for effective heating or cooling systems. Moreover, proper adjustment of the heat transfer fluid is also important from the viewpoint of the correct operation, maintenance, and cost efficiency of these systems. Therefore, in this paper, a detailed review of recent work on the subject of conventional and novel heat transfer fluid applications is presented. Particular...
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Upper Limb Bionic Orthoses: General Overview and Forecasting Changes
PublikacjaUsing robotics in modern medicine is slowly becoming a common practice. However, there are still important life science fields which are currently devoid of such advanced technology. A noteworthy example of a life sciences field which would benefit from process automation and advanced robotic technology is rehabilitation of the upper limb with the use of an orthosis. Here, we present the state-of-the-art and prospects for development...
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Instrumented End Notched Flexure - Crack propagation and process zonemonitoring. Part I: Modelling and analysis
PublikacjaAnalysis of the three-point bending, End Notched Flexure (ENF), test is presented for exploitation with a new experimental methodology using the backface strain monitoring technique. The model consists oftwo Timoshenko beams joined with a two parameter elastic foundation, to evaluate stress and strain fields in both adherends and the adhesive layer, together with the specimen compliance and energyrelease rate. This model is compared...
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Horizontally-split-drain MAGFET - a highly sensitive magnetic field sensor
PublikacjaWe propose a novel magnetic field sensitive semiconductor device, viz., Horizontally-Split-Drain Magnetic-Field Sensitive Field-Effect Transistor (HSDMAGFET) which can be used to measure or detect steady or variable magnetic fields. Operating principle of the transistor is based on one of the galvanomagnetic phenomena and a Gradual Channel Detachment Effect (GCDE) and is very similar to that of Popovic and Baltes's SDMAGFET. The...
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THE INFLUENCE OF THE URBAN DESIGN ON THE AIR EXCHANGE IN CITIES. SELECTED PROBLEMS IN POLISH REALITY
PublikacjaThe progress of the architecture and urbanism raises problems requiring interdisciplinary research conducted with the use of advanced experimental techniques and computer simulation. The fields of this research include aerodynamics, especially in intensively developed area of Environmental Wind Engineering (EWE). Aerodynamic phenomena occurring around buildings have a significant impact on the quality of the climate in the cities....
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Comparative Analysis of Numerical and Experimental Studies of the Airflow Around the Sample of Urban Development
PublikacjaIn 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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Novel Analytic-Numerical Model of Free Convection: with Leading Edge Considered
PublikacjaA novel solution of the free convection boundary problem is represented in analytical form for velocity and temperature for an isothermal vertical plate, as an example. These fields are built as a Taylor Series in the x coordinate with coefficients as functions of the vertical coordinate (y). We restrict ourselves by cubic approximation for both functions. The basic Navier-Stokes and Fourier-Kirchhoff equations and boundary conditions...
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Julita Wasilczuk dr hab.
OsobyUrodzona 5 kwietnia 1965 roku w Gdańsku. W latach 1987–1991 odbyła studia na Wydziale Ekonomiki Transportu Uniwersytetu Gdańskiego (obecnie Wydział Ekonomii). Od 1993 roku zatrudniona na nowo utworzonym Wydziale Zarządzania i Ekonomii, Politechniki Gdańskiej, na stanowisku asystenta. W 1997 roku uzyskała stopień doktora nauk ekonomicznych na WZiE, a w 2006 doktora habilitowanego nauk ekonomicznych w dyscyplinie nauki o zarządzaniu,...
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Projekt optymalnego łuku poziomego jako element nauczania kształtowania układów geometrycznych toru
PublikacjaAspekt geometryczny stanowi ważny element w nauczaniu projektowania dróg szynowych na studiach 1-go i 2-go stopnia na Wydziale Inżynierii Lądowej i Środowiska Politechniki Gdańskiej. Podstawowym, najczęściej spotykanym w praktyce elementem linii kolejowej w planie jest łuk poziomy z krzywymi przejściowymi. Z tego względu na Wydziale Inżynierii Lądowej i Środowiska Politechniki Gdańskiej wdrożono ćwiczenie projektowe ujmujące to...
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Optimizing the computation of a parallel 3D finite difference algorithm for graphics processing units
PublikacjaThis paper explores the possibilities of using a graphics processing unit for complex 3D finite difference computation via MUSTA‐FORCE and WENO algorithms. We propose a novel algorithm based on the new properties of CUDA surface memory optimized for 2D spatial locality and compare it with 3D stencil computations carried out via shared memory, which is currently considered to be the best approach. A case study was performed for...
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Connecting orbits for a periodically forced singular planar Newtonian system
PublikacjaW niniejszym artykule badamy problem istnienia i krotności rozwiązań homoklinicznych i heteroklinicznych dla nieautonomicznych układów Newtonowskich na płaszczyźnie z potencjałem okresowym ze względu na zmienną czasową, mającym maksimum globalne właściwe przyjmowane w dwóch punktach płaszczyzny i punkt osobliwy (studnię nieskończonej głębokości), w otoczeniu którego potencjał spełnia warunek Gordona (gradient potencjału ze względu...
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Selected aspects of the evolution of the industry analysis
PublikacjaPorter's five forces is a significant tool of analysis of industries. It helps evaluating variables of industry profitability and assessing firm performance. Using the framework, managers can take a decision as to which industries they can effectively compete in and position their companies to reduce the adverse effects of the mentioned forces. According to the critics, the five forces model is limited to its static nature. The...
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Identification of diagnostic parameter sensitivity during dynamic processes of a marine engine
PublikacjaChanging some parameters of the engine structure alters the emission of harmful components in the exhaust gas. This applies in particular to the damage of charge exchange system as well as fuel system and engine supercharger. These changes are much greater during the dynamic states and their accompanying transitional processes. The different sensitivity of diagnostic parameters to the same force, coming from the engine structure, but...
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INVESTIGATION OF JOURNAL SLIDE BEARINGS UNDER THE ANGLE OF THEIR FUNCTIONING
PublikacjaPaper presents the structure and principle of operation of a stand for measurements of influence of the lubrication method and process on functioning of journal slide bearings in their various technical states. Measurements performed on the stand make it possible to take advantage of the new method of evaluating the influence of physical and chemical properties of lubricating oil on the coefficient of friction in the mixed friction...
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Effectiveness of a mathematical model in simulating nonlinear mechanical behaviour of a seismic isolation system made of polymeric bearings
PublikacjaThe present study was focused on determining the effectives of a nonlinear mathematical model in simulating complex mechanical behaviour of a seismic isolation system made of Polymeric Bearings. The proposed mathematical model defines the lateral force as a nonlinear function of the shear displacement and the deformation velocity. The effectiveness of the proposed mathematical model was verified by comparing the seismic response...
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The networking of the justice system as part of public court networks
PublikacjaThe goal of this paper is to look at the organizational structure of the justice system and provide the answer to the basic question of the possible network relations, their force, and imapct. As part od the paper, I have defined public inetrorganisational court network, dividing them into regulatory inter-organisational networks nad voluntary inetrorganisational networks. Emphasis has also been placed on the benefits and threats...
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The mechanism of grouting action under the base of bored pile
PublikacjaThe grouting under the base of bored pile is carried out in order to reduce pile settlement and improve its bearing capacity. The principal aim of grouting is to introduce an initial force between the soil and the pile base. In non-cohesive soil, the grouting can also enlarge the pile base area and therefore improve the base resistance. The example of static load tests on instrumented bored piles installed with and without grouting...
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Sensorless induction motor drive with voltage inverter and sine-wave filter
PublikacjaThis paper presents a speed sensorless control system of an induction motor with an output LC filter. It is known that the parameters design of the filter gives sine wave motor supply voltage but complicates control and estimation process. The reason is that the voltage drop and phase shift between filter input and output signals are imposed, and hence the motor voltages and currents differ from the inverter output waveforms. To...
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Synergistic effect of multi walled carbon nanotubes and reduced graphene oxides in natural rubber for sensing application
PublikacjaUtilizing the electrical properties of polymer nanocomposites is an important strategy to develop high performance solvent sensors. Here we report the synergistic effect of multi walled carbon nanotubes (MWCNTs) and reduced graphene oxide (RGO) in regulating the sensitivity of the naturally occurring elastomer, natural rubber (NR). Composites were fabricated by dispersing CNTs alone and together with exfoliated RGO sheets (thermally...
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Two tests for adhesive bonding long term characterization: principles and applications
PublikacjaThis article describes recent refinement of the traditional wedge test technique used to characterize durability of the adhesive joints. We propose two types of measuring protocols to monitor precisely and continuously the propagation of an "effective" crack during long term mode I fracture mechanic test. First method is directly derived from the traditional wedge test technique and consist in monitoring the surface strain of adherent...
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Process zone in the Single Cantilever Beam under transverse loading. - Part I: Theoretical analysis
PublikacjaSingle Cantilever Beam (SCB) specimen loaded with a transverse force parallel to the crack front is proposed for the analysis of crack propagation phenomena under mixed mode conditions. The stress redistribution in the adhesive layer in the vicinity of the crack front so as the beam deformation are estimated using a Timoshenko beam on elastic foundation model. This model emphasizes the Mode II contribution due to flexural beam...
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Properties of Nasicon-based CO2 sensors with Bi8Nb2O17 reference electrode
PublikacjaPotentiometric CO2 sensors based on Nasicon (Na+ conductor, Na3Zr2Si2PO12) electrolyte, Bi8Nb2O17/Pt reference electrode and different sensing electrodes have been prepared. Besides the sensing electrode material, sensors differ from each other in the reference electrode preparation technique. The main aim of this study is to investigate sensor construction and electrode fabrication process influence on sensor properties. The optimal...
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AN OVERVIEW OF HEAT TRANSFER ENHANCEMENT BASED UPON NANOPARTICLES INFLUENCED BY INDUCED MAGNETIC FIELD WITH SLIP CONDITION VIA FINITE ELEMENT STRATEGY
PublikacjaThe mathematical model of heat generation and dissipation during thermal energy transmission employing nanoparticles in a Newtonian medium is investigated. Dimensionless boundary layer equations with correlations for titanium dioxide, copper oxide, and aluminium oxide are solved by the finite element method. Parameters are varied to analyze their impact on the flow fields. Various numerical experiments are performed consecutively...
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A current-controlled FET
PublikacjaA novel semiconductor device, viz., Horizontally-Split-Drain Current-Controlled Field-Effect Transistor (HSDCCFET) with two control electrodes is proposed in this works. For the sake of brevity, the device can be called a CCFET. Operating principle of the proposed transistor is based on one of the galvanomagnetic phenomena, the Biot-Savart-Laplace law and a Gradual Channel Detachment Effect (GCDE). The transistor is dedicated...
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E-learning in tourism and hospitality: A map
PublikacjaThe impact of information and communication technologies (ICT) on tourism and hospitality industries has been widely recognized and investigated as a one of the major changes within the domains in the last decade: new ways of communicating with prospective tourists and new ways of purchasing products arisen are now part of the industries’ everyday life. Poor attention has been paid so far to the role played by new media in education...
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Building Project and Project Team Characteristics For Creating Hybrid Management Processes
PublikacjaThis paper introduces a method of building the characteristic of Software Development Project. Project characteristic is determined on the basis of several factors such as the complexity of Software Development Project and Project Team, results of historical projects and information on processes and methodologies, which are implemented in analyzed organizations. Information on project complexity can be applied to many different...
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Combined Close Range Photogrammetry and Terrestrial Laser Scanning for Ship Hull Modelling
PublikacjaThe paper addresses the fields of combined close-range photogrammetry and terrestrial laser scanning in the light of ship modelling. The authors pointed out precision and measurement accuracy due to their possible complex application for ship hulls inventories. Due to prescribed vitality of every ship structure, it is crucial to prepare documentation to support the vessel processes. The presented methods are directed, combined...
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A Simple Neural Network for Collision Detection of Collaborative Robots
PublikacjaDue to the epidemic threat, more and more companies decide to automate their production lines. Given the lack of adequate security or space, in most cases, such companies cannot use classic production robots. The solution to this problem is the use of collaborative robots (cobots). However, the required equipment (force sensors) or alternative methods of detecting a threat to humans are usually quite expensive. The article presents...
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Longitudinal Motion Due to Action of Tunnel Thrusters
PublikacjaTunnel thrusters are propulsion and active control devises that provide a side force, or transverse thrust, to support mooring operations or position keeping. They shorten the time of manoeuvring, reduce the cost of towage and since inception, manoeuvrability specifically in ports has become a lot easier. Tunnel thrusters can either be operated manually or with the help of Dynamic Positioning systems which makes it even more efficient. Theoretically,...
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Towards a classification of networks with asymmetric inputs
PublikacjaCoupled cell systems associated with a coupled cell network are determined by (smooth) vector fields that are consistent with the network structure. Here, we follow the formalisms of Stewart et al (2003 SIAM J. Appl. Dyn. Syst. 2, 609–646), Golubitsky et al (2005 SIAM J. Appl. Dyn. Syst. 4, 78–100) and Field (2004 Dyn. Syst. 19, 217–243). It is known that two non-isomorphic n-cell coupled networks can determine the same sets of...
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Compression test results of fused filamend fabricated polylactyde and polylactyde with carbon fiber filler
Dane BadawczeThe DataSet contains the results of the mechanical behaviour of cube specimens with dimensions 30 x 30 x 30 cm3. The specimens were additively manufactured with the fused filament fabrication (FFF) method. They used two different materials polylactide (PURE PLA) and polylactide with carbon fibre filler (PLA+CF). The specimens were segregated into three...
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Tensile strength test of PE foils modified with zinc oxide and zinc salts
Dane BadawczeThis dataset contains the results of PE foils mechanical tests, in which the material was evaluated for strength and extensibility at the moment of breaking and based on the same tests preceded by material fatigue in 50 stretching cycles. The principle of the method is to stretch the test sample placed in the clamps of the stretching apparatus at a...
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Images of topography and mechanical properties (phase imaging) of cast iron samples from water installations
Dane BadawczeMeasurements in contact and semi-contact mode. NTEGRA Prima (NT-MDT) device. CSG 10.
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Imaging of graphene surface by means of tapping mode AFM
Dane BadawczeGraphene [1] is a material consisting of carbon planes with a hexagonal structure. One of the facts of interest from a purely scientific point of view is the very high mobility of electrons in the described material, allowing the study of relativistic effects inside a solid sample. Other features, such as bactericidal activity, make graphene an interesting...