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Search results for: NUMERICAL SIMULATIONS, POLLUTION MIGRATION, METHOD OF FINITE VOLUMES, DISPERSION
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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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Numerical Estimation of Hull Hydrodynamic Derivatives in Ship Maneuvering Prediction
PublicationPrediction of the maneuvering characteristics of the ship at the design stage can be done by means of model tests, computational simulations or a combination of both. The model tests can be realized as direct simulation of the standard maneuvers with the free running model, which gives the most accurate results, but is also the least affordable as it requires very large tank or natural lake, as well as complex equipment of the...
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Numerical Analysis of Steady Gradually Varied Flow in Open Channel Networks with Hydraulic Structures
PublicationIn this paper, a method for numerical analysis of steady gradually varied fl ow in channel networks with hydraulic structures is considered. For this purpose, a boundary problem for the system of ordinary differential equations consisting of energy equation and mass conservation equations is formulated. The boundary problem is solved using fi nite difference technique which leads to the system of non-linear algebraic equations....
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Smooth Particle Hydrodynamics (SPH) approach in simulating large penetration into soil
PublicationA study of Smooth Particle Hydrodynamics (SPH) approach for predicting large soil deformation is presented. Theoretical basics of SPH method, including the equations governing, discussion of the importance of smoothing function length, contact formulation, boundary treatment and finally utilization in hydrocodes simulations are presented. An application of SPH to a real case of large penetrations (crater creating) into soil caused...
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Wybrane elementy nieliniowej dynamiki struktur kratowych
PublicationW pracy jest dyskutowany problem nieliniowej dynamiki struktur kratowych. Zastosowano stacjonarny opis Lagrange'a (ang. Total Lagrange), pokazano silne i słabe sformułowanie dla pręta kratowego, jego aplikację do MES. W zakresie całkowania równań ruchu przedstawiono metodę Newmarka i metodę-a dla problemów liniowych i nieliniowych. Załączony przykład numeryczny ilustruje cechy przedstawionych metod.
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Matrix solid-phase dispersion (MSPD) as simple and useful sample preparation technique for determination of polybrominated diphenyl ethers (PBDEs) in dust
PublicationIn the present study a novel analytical procedure for the determination of polybrominated diphenylethers in dust samples was developed.The main aim of the research was the selection of the optimum conditions of the matrix solid-phasedispersion before thefinal determination of polybrominated diphenyl ethers in dust samples. In order toassess the best usefulness of this technique, a favourable ratio of sample amount to the mass ofdispersing...
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Fabrication of anti-corrosion nitrogen doped graphene oxide coatings by electrophoretic deposition
PublicationThis work assesses anti-corrosion properties of graphene and N-doped graphene coatings deposited on copper by an electrophoretic method. Graphene oxide (GO) precursor was synthesized by an improved Hummers' method, whereas N-doping was performed hydrothermally in the presence of ammonia. After nitrogenation, doped graphene oxide samples (NGO) contained a reduced amount of oxygen and about 9% w/w nitrogen as pyridinic, pyrrole,...
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Efficient knowledge-based optimization of expensive computational models using adaptive response correction
PublicationComputer simulation has become an indispensable tool in engineering design as they allow an accurate evaluation of the system performance. This is critical in order to carry out the design process in a reliable manner without costly prototyping and physical measurements. However, high-fidelity computer simulations are computationally expensive. This turns to be a fundamental bottleneck when it comes to design automation using numerical...
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Discrete identification of continuous non-linear and non-stationary dynamical systems that is insensitive to noise correlation and measurement outliers
PublicationThe paper uses specific parameter estimation methods to identify the coefficients of continuous-time models represented by linear and non-linear ordinary differential equations. The necessary approximation of such systems in discrete time in the form of utility models is achieved by the use of properly tuned `integrating filters' of the FIR type. The resulting discrete-time descriptions retain the original continuous parameterization...
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FEM modelling of screw displacement pile interaction with subsoil
PublicationPredicting the-settlement characteristics of piles is an important element in the designing of pile foundations. The most reliable method in evaluating pile-soil interaction is the static load test, preferably performed with instrumentation for measuring shaft and pile base resistances. This, however, is a mostly post-implementation test. In the design phase, prediction methods are needed, in which numerical simulations play an...
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Modelling hydraulic and capillary-driven two-phase fluid flow in unsaturated concretes at the meso-scale with a unique coupled DEM-CFD technique
PublicationThe goal of the research was to demonstrate the impact of thin porous interfacial transition zones (ITZs) between aggregates and cement matrix on fluid flow in unsaturated concrete caused by hydraulic/capillary pressure. To demonstrate this impact, a novel coupled approach to simulate the two-phase (water and moist air) flow of hydraulically and capillary-driven fluid in unsaturated concrete was developed. By merging the discrete...
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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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Numerical Modelling of Forced Convection of Nanofluids in Smooth, Round Tubes: A Review
PublicationA comprehensive review of published works dealing with numerical modelling of forced convection heat transfer and hydrodynamics of nanofluids is presented. Due to the extensive literature, the review is limited to straight, smooth, circular tubes, as this is the basic geometry in shell-and-tube exchangers. Works on numerical modelling of forced convection in tubes are presented chronologically in the first part of the article....
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A comparative analysis of numerically simulated and experimentally measured static responses of a floating dock
PublicationTwo numerical methods, dynamic and static analyses, are proposed to calculate the static responses of a floating dock under different ballast water distributions. Model-scale experimental tests were conducted to compare with these numerical methods. The dynamic analysis includes a 6-degree-of-freedom (6-DOF) model, a hydrostatic force model and a hydrodynamic force model to simulate the dock's freely floating processes. The dock's...
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Simulation of Signal Propagation Along Fractional-Order Transmission Lines
PublicationIn this paper, the simulation method of signal propagation along fractional-order (FO) transmission lines is presented. Initially, fractional calculus and the model of FO transmission line are introduced. Then, the algorithm allowing for simulation of the nonmonochromatic wave propagation along FO transmission lines is presented. It employs computations in the frequency domain, i.e., an analytical excitation is transformed to the...
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Comparison of AHP and Numerical Taxonomy Methods Based on Biogas Plant Location Analysis
PublicationThe paper presents a comparison of the multi-criteria Analytic Hierarchy Process (AHP) method and numerical taxonomy in biogas plant location selection. Biogas plants are sources that will significantly contribute to the implementation of the provisions of the energy and climate package for Poland by 2030. Increasing the share of energy produced from renewable sources, e.g. biogas plants, will increase the country’s energy security....
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A design framework for rigorous constrained EM-driven optimization of miniaturized antennas with circular polarization
PublicationCompact radiators with circular polarization are important components of modern mobile communication systems. Their design is a challenging process which requires maintaining simultaneous control over several performance figures but also the structure size. In this work, a novel design framework for multi-stage constrained miniaturization of antennas with circular polarization is presented. The method involves sequential optimization...
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Heat transfer intensification by jet impingement – numerical analysis using RANS approach
PublicationJet impingement is a method of the heat transfer enhancement applied in the engineering systems. The idea is to generate fast-flow fluid jet which impinge on the heated (or cooled) surface, causing significantly higher heat transfer rate. Although some flat surface jet impingement cases are described in the literature, the validated data is still limited. The reason is coming from the fact, that these flows are hydrodynamically...
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Miniaturized Solid Phase Extraction techniques for different kind of pollutants analysis: State of the art and future perspectives – PART 1
PublicationSolid Phase Extraction (SPE) has been practiced in a modern form for more than half a century. It was constantly developing, driven by the analysts needs. These needs are coming from the importance to select an appropriate analytical method, which should have satisfactory accuracy, precision and sensitivity. In the case of sorbent-based microextraction techniques, the choice of miniaturized variants that meet these requirements...
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About Unusual Diffraction and Thermal Self-Action of Magnetosonic Beam
PublicationThe dynamics of slightly diverging two-dimensional beams whose direction forms a constant angle θ with the equilibrium straight magnetic strength is considered. The approximate dispersion relations and corresponding links which specify hydrodynamic perturbations in confined beams are derived. The study is dedicated to the diffraction of a magnetosonic beam and nonlinear thermal self-action of a beam in a thermoconducting gaseous plasma....
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An Improved Method of Minimizing Tool Vibration during Boring Holes in Large-Size Structures
PublicationThe paper presents a thoroughly modified method of solving the problem of vibration suppression when boring large-diameter holes in large-size workpieces. A new approach of adjusting the rotational speed of a boring tool is proposed which concerns the selection of the spindle speed in accordance with the results of the simulation of the cutting process. This streamlined method focuses on phenomenological aspects and involves the...
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Diagnosis of Damage in a Steel Tank with Self-Supported Roof through Numerical Analysis
PublicationThe safety of civil engineering structures is one of the most important issues of building industry. That is why the assessment of the damage-involved structural response has recently become of major concern to engineers. Among a number of different approaches to diagnosis of damage, the method of measuring the changes in natural frequencies is considered to be one of the most effective indicators of global damage. From the practical...
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Guided Wave Propagation in Detection of Partial Circumferential Debonding in Concrete Structures
PublicationThe following article presents results of investigating the damage detection in reinforced concrete beams with artificially introduced debonding between the rod and cover, using a non-destructive method based on elastic waves propagation. The primary aim of the research was to analyze the possible use of guided waves in partial circumferential debonding detection. Guided waves were excited and registered in reinforced concrete...
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A Generalized Framework Towards Structural Mechanics of Three-layered Composite Structures
PublicationThree-layered composite structures find a broad application. Increasingly, composites are being used whose layer thicknesses and material properties diverge strongly. In the perspective of structural mechanics, classical approaches to analysis fail at such extraordinary composites. Therefore, emphasis of the present approach is on arbitrary transverse shear rigidities and structural thicknesses of the individual layers. Therewith...
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Computational analysis of power-law fluids for convective heat transfer in permeable enclosures using Darcy effects
PublicationNatural convection is a complex environmental phenomenon that typically occurs in engineering settings in porous structures. Shear thinning or shear thickening fuids are characteristics of power-law fuids, which are non-Newtonian in nature and fnd wide-ranging uses in various industrial processes. Non-Newtonian fuid fow in porous media is a difcult problem with important consequences for energy systems and heat transfer. In this...
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Validation of Hydraulic Mechanism during Blowout Trauma of Human Orbit Depending on the Method of Load Application
PublicationThe more we know about mechanisms of the human orbital blowout type of trauma, the better we will be able to prevent them in the future. As long as the buckling mechanism’s veracity is not in doubt, the hydraulic mechanism is not based on equally strong premises. To investigate the correctness of the hydraulic mechanism’s theory, two different methods of implementation of the hydraulic load to the finite element method (FEM) model...
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Identification of Unstable Reference Points and Estimation of Displacements Using Squared Msplit Estimation
PublicationThe article presents a new version of the method for estimating parameters in a split functional model, which enables the determination of displacements of geodetic network points with constrained datum. The main aim of the study is to present theoretical foundations of Msplit CD estimation and its basic properties and possible applications. Particular attention was paid to the efficacy of the method in the context of geodetic...
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Analiza wydajności kolektora słonecznego przeznaczonego dla systemu ogrzewania budynku o niskim zapotrzebowaniu na ciepło
PublicationNiniejsza praca przedstawia wyniki badań numerycznych kolektora słonecznego, przeznaczonego dla budynków o niskim zapotrzebowaniu na ciepło. W pracy przedstawiono nowatorską koncepcję kolektora słonecznego o obniżonej wydajności, niskich kosztach wykonania oraz wykorzystującego istniejące elementy konstrukcji przekryć budynku. Istotną zaletą kolektora jest brak ingerencji w architekturę zewnętrzną budynku. Za pomocą symulacji numerycznej...
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Determination of trace levels of eleven bisphenol A analogues in human blood serum by high performance liquid chromatography–tandem mass spectrometry
PublicationChemicals showing structural or functional similarity to bisphenol A (BPA), commonly called BPA analogues, have recently drawn scientific attention due to their common industrial and commercial application as a substitute for BPA. In the European Union, the use of BPA has been severely restricted by law due to its endocrine disrupting properties. Unfortunately, it seems that all BPA analogues show comparable biological activity,...
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Experimental and numerical evaluation of mechanical behaviour of composite structural insulated panels
PublicationComposite 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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A conceptual design and numerical analysis of the mixerless urea-SCR system
PublicationIn the present study, an innovative design of the urea-selective catalytic reduction (SCR) system without conventional mixing elements was developed. The aim was to obtain a high degree of urea decomposition, and uniform ammonia distribution at the inlet to the catalyst, while minimising the liquid film deposition and keeping the compact design. The concept of the design was based on creating high turbulences and elongating...
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Prediction of manoeuvring abilities of 10000 DWT pod-driven coastal tanker
PublicationThis paper aims to present a new approach in the prediction of manoeuvring abilities of pod-driven ships. A new mathematical model of motions based on MMG methodology was developed and a new type of description of forces acting on azimuth drives is presented. Captive model tests of medium-size coastal tanker and pod open water tests were carried out in CTO S.A. (Ship Design and Research Centre S.A.) to obtain hull hydrodynamic derivatives...
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Multi-Beam Antenna for Ka-Band CubeSat Connectivity Using 3-D Printed Lens and Antenna Array
PublicationIn this paper, the design of a passive multi-beam lens antenna is proposed for the CubeSat space communication system as an alternative application of a 2-D microstrip antenna array that has originally been designed for a 39 GHz 5 G MU-MIMO system. The half-ellipsoid lens is 3-D printed using stereolithography (SLA) technology. The antenna prototype is capable of selecting the main beam between 16 different directions with a gain...
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Modelling of sequencing batch reactor operating at various aeration modes
PublicationThe presented study involved designing a computer model of a sequencing batch reactor (SBR) at laboratory scale. The data pertaining to the technical aspects of the bioreactor and quality indicators of wastewater constituted the input for the employed simulation tool, i.e. GPS-X software package. The results of a simulation involving a 12-hour operation cycle are presented in this work; each cycle included 6 phases: filling, mixing,...
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Results of the “DPDT-Auger” Research Project on Screw Displacement Piles
PublicationThe main objective of the “DPDT-Auger” research project was to test the prototype DPDT auger for forming screw displacement piles in the ground (patented in Poland in 2020). An additional aim was to develop design methods and rules for the making of such piles. The augers and piles were first tested on a model scale, and then more extensively in the real scale on experimental field plots. The results found the overall functionality...
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Prediction of the fatigue lifetime of PUR structural elements using a combined experimental-numerical approach
PublicationThis paper presents a method for estimating the fatigue life of polyurethane elastomeric components. A rubber replacement - polyurethane of hardness 80ShA commonly used in vibration damping systems, for example, in motor vehicle suspensions, was used for the study. A metal-rubber bushing component was selected for analysis, and numerical analysis was carried out along with a fatigue model proposal based on a modification of the...
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MODELLING OF CONCRETE FRACTURE AT AGGREGATE LEVEL USING DEM BASED ON X-RAY mu CT IMAGES OF INTERNAL STRUCTURE
PublicationThe paper describes two-dimensional meso-scale numerical results of fracture in notched concrete beams under quasi-static three-point bending. Concrete was modelled as a random heterogeneous 4-phase material composed of aggregate particles, cement matrix, interfacial transitional zones (ITZs) and air voids. As a numerical approach, the discrete element method (DEM) was used. The concrete micro-structure in calculations was directly...
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Multi-layered mineral glass units used as viewport elements of underwater ship structures
PublicationIn the paper, Authors deals with viewport elements of underwater marine constructions. If a single-plate viewport constructions are considered, big thicknesses of the glass plate are required to resist the pressure. To build the viewports from the commercially accessible glass panes, multi-layered glass units are proposed in the paper. Numerical calculations are presented, summarized and compared with experimental tests. Focusing...
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Expedited Optimization of Passive Microwave Devices Using Gradient Search and Principal Directions
PublicationOver the recent years, utilization of numerical optimization techniques has become ubiquitous in the design of high-frequency systems, including microwave passive components. The primary reason is that the circuits become increasingly complex to meet ever growing performance demands concerning their electrical performance, additional functionalities, as well as miniaturization. Nonetheless, as reliable evaluation of microwave device...
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Typology of the Black Tents Architecture between Iranian nomad tribes
PublicationEvidence of the past shows variation in human settlements. Nomadic house the” Black Tent” shows relationship between humans and the natural environment surrounding them. Black Tents are made of natural materials consistant with environmental conditions. This paper discusses nomadic living space of some Iranian tribes located in different regions to show their unique architecture and culture. Rediscovering different architecture...
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Diagnosis of marine internal combustion engines by means of rapidly variable temperature and composition of exhaust gas as an alternative or support for currently used diagnostic methods
PublicationThe article points out relevance of parametric diagnostics of ship engines and analyzes the state of research in this field. A method is proposed for diagnosing engine systems on the basis of rapidly variable exhaust temperature while measuring its composition. A method for determining diagnoser tools from the signal within one engine cycle and mathematical and statistical treatment of test results is presented. The products of...
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Towards application of uncertainty quantification procedure combined with experimental procedure for assessment of the accuracy of the DEM approach dedicated for granular flow modeling
PublicationThere is a high demand for accurate and fast numerical models for dense granular flows found in many industrial applications. Nevertheless, before numerical model can be used its need to be always validated against experimental data. During the validation, it is important to consider how the measurement data sets, as well as the numerical models, are affected by errors and uncertainties. In this study, the uncertainty quantification...
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HILS for the Design of Three-Wheeled Mobile Platform Motion Surveillance System with a Use of Energy Performance Index
PublicationCurrent tendency in mechatronic design requires the use of comprehensive development of an environment, which gives the possibility to prototype, design, simulate and integrate with dedicated hardware. The paper discusses the Hardware-In-the-Loop Simulations (HILS) mechatronic technique, used during the design of the surveillance system based on energy performance index. The presented test configuration (physical controller – emulated...
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Chitin nanowhiskers from shrimp shell waste as green filler in acrylonitrile-butadiene rubber: Processing and performance properties
PublicationIn this work, chitin nanowhiskers with high crystallinity index were obtained from shrimp shells waste using acid hydrolysis method and then comprehensively characterized. Subsequently, the impact of chitin nanowhisker content on processing and performance of acrylonitrile-butadiene rubber based nanocomposites was evaluated. The results showed that the addition of chitin nanowhiskers increased tensile strength and tear strength...
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Resonant Frequencies in the Open Microstrip Structures Placed on Curved Surfaces
PublicationThe paper presents the research on open microstrip structures placed on curved surfaces such as cylindrical, elliptical or spherical. The numerical analysis of investigated structures is based on expansion of electric and magnetic fields into suitable function series. Utilizing the continuity conditions the boundary problem is formulated which is solved with the use of method of moments. The investigated structures find application...
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Scale effect in the self-propulsion prediction for Ultra Large Container Ship with contra-rotating propellers
PublicationThis article addresses the problem of the scale effect for an Ultra Large Container Ship (ULCS) with a novel twin-crp-pod propulsion system. Twin-crp-pod steering-propulsion arrangement is an innovative solution that gains from three well-known systems: twin-propeller, contra-rotating propellers and pod propulsors. It is expected that applying the twin-crp-pod system to the analysed Ultra Large Container Ship will increase propulsion...
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Healthier and Environmentally Responsible Sustainable Cities and Communities. A New Design Framework and Planning Approach for Urban Illumination
PublicationAlthough sustainability and sustainable development are both considered necessary practices in various fields today, a recent analysis showed that the Sustainable Development Goal SDG11: Sustainable Cities and Communities established by the United Nations does not address urban illumination and its impact. This oversight is of concern because research carried out in the last 20+ years indicates artificial light at night (ALAN)...
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Laboratory Determination of Burger's Model Parameters for Visco-elastic Analysis of Road Pavement Materials
PublicationBurger's Model is one of those models that describes performance of asphalt mixtures. Its parameters can be used in road construction analysis based on visco-elastic properties in wide variety of temperatures using dedicated programs (e.g. Veroad) or in Finite Element Method (FEM). Parameters of Burger's Model can be used for example in prediction of low temperature cracking in low winter temperatures or permanent deformation...
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Determination of magnetisation conditions in a Double-Core Barkhausen Noise measurement set-up
PublicationThe magnetic Barkhausen effect is useful forassessing 1D and 2D stress states of ferromagnetic steelobjects. However, its extension to technically importantmaterials, such as duplex anisotropic steels, remains challenging. The determination of magnetisation inside the studied object and the electromagnet for various geometries, materials and magnetisation angles is a key issue.Three-dimensional, dynamic finite element analysis...
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A Comparative Study on Methods of Distinction Between Near- and Far-Side Defects as Techniques Used Alongside with the Magnetic Flux Leakage Testing
PublicationResults of the finite element analysis show that a far-side defect in a steel plate, with the depth greater by 10% of the plate thickness than a near-side defect, can produce a very similar magnetic flux leakage (MFL) signal. Due to the fact that a measurement of MFL itself can lead to misclassification of a far-side defect as a near-side one, and thus to underestimation of its depth, a comparative study of three complementary...