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Optimum number of actuators to minimize the cross-sectional area of prestressable cable and truss structures
PublicationThis paper describes a new computational method for determining the optimum number of actuators to design the optimal and economic cross-sectional area of pin-jointed assemblies based on the conventional force method. The most active members are selected to be prestressed to redistribute stress in the whole structure, resulting in regulating the internal force of bars that face high stress. Reducing stress in critical members allows...
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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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Machine learning-based seismic fragility and seismic vulnerability assessment of reinforced concrete structures
PublicationMany studies have been performed to put quantifying uncertainties into the seismic risk assessment of reinforced concrete (RC) buildings. This paper provides a risk-assessment support tool for purpose of retrofitting and potential design strategies of RC buildings. Machine Learning (ML) algorithms were developed in Python software by innovative methods of hyperparameter optimization, such as halving search, grid search, random...
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Optimal reshaping and stress controlling of double-layer spherical structures under vertical loadings
PublicationOptimal reshaping and stress controlling of double-layer spherical structures under vertical loadings
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A New Adaptive Method for the Extraction of Steel Design Structures from an Integrated Point Cloud
PublicationThe continuous and intensive development of measurement technologies for reality modelling with appropriate data processing algorithms is currently being observed. The most popular methods include remote sensing techniques based on reflected-light digital cameras, and on active methods in which the device emits a beam. This research paper presents the process of data integration from terrestrial laser scanning (TLS) and image data...
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Revealing the Frank–Evans “Iceberg” Structures within the Solvation Layer around Hydrophobic Solutes
PublicationUsing computer simulations, the structural properties of solvation water of three model hydrophobic molecules, methane and two fullerenes (C60 and C80), were studied. Systems were simulated at temperatures in the range of 250−298 K. By analyzing both the local ordering of the molecules of water in the solvation layers and the structure of hydrogen bond network, it is shown that in the solvation layer of hydrophobic molecules, ordered...
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Improved Modeling of Microwave Structures Using Performance-Driven Fully-Connected Regression Surrogate
PublicationFast replacement models (or surrogates) have been widely applied in the recent years to accelerate simulation-driven design procedures in microwave engineering. The fundamental reason is a considerable—and often prohibitive—CPU cost of massive full-wave electromagnetic (EM) analyses related to solving common tasks such as parametric optimization or uncertainty quantification. The most popular class of surrogates are data-driven...
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Normalized Partial Scattering Cross Section for Performance Evaluation of Low-Observability Scattering Structures
PublicationThe development of diffusion metasurfaces created new opportunities to elevate the stealthiness of combat aircraft. Despite the potential significance of metasurfaces, their rigorous design methodologies are still lacking, especially in the context of meticulous control over the scattering of electromagnetic (EM) waves through geometry parameter tuning. Another practical issue is insufficiency of the existing performance metrics,...
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Reliable EM-driven size reduction of antenna structures by means of adaptive penalty factors
PublicationMiniaturization has become of paramount importance in the design of modern antenna systems. In particular, compact size is essential for emerging application areas such as internet of things, wearable and implantable devices, 5G technology, or medical imaging. On the other hand, reduction of physical dimensions generally has a detrimental effect on antenna performance. From the perspective of numerical optimization, miniaturization...
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Accurate Modeling of Antenna Structures by Means of Domain Confinement and Pyramidal Deep Neural Networks
PublicationThe importance of surrogate modeling techniques has been gradually increasing in the design of antenna structures over the recent years. Perhaps the most important reason is a high cost of full-wave electromagnetic (EM) analysis of antenna systems. Although imperative in ensuring evaluation reliability, it entails considerable computational expenses. These are especially pronounced when carrying out EM-driven design tasks such...
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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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On Nature-Inspired Design Optimization of Antenna Structures Using Variable-Resolution EM Models
PublicationNumerical optimization has been ubiquitous in antenna design for over a decade or so. It is indispensable in handling of multiple geometry/material parameters, performance goals, and constraints. It is also challenging as it incurs significant CPU expenses, especially when the underlying computational model involves full-wave electromagnetic (EM) analysis. In most practical cases, the latter is imperative to ensure evaluation reliability....
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Expedited Yield-Driven Design of High-Frequency Structures by Kriging Surrogates in Confined Domains
PublicationUncertainty quantification is an important aspect of engineering design, also pertaining to the development and performance evaluation of high-frequency structures systems. Manufacturing tolerances as well as other types of uncertainties, related to material parameters (e.g., substrate permittivity) or operating conditions (e.g., bending) may affect the characteristics of antennas or microwave devices. For example, in the case...
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On Improved-Reliability Design Optimization of High-Frequency Structures Using Local Search Algorithms
PublicationThe role of numerical optimization has been continuously growing in the design of high-frequency structures, including microwave and antenna components. At the same time, accurate evaluation of electrical characteristics necessitates full-wave electromagnetic (EM) analysis, which is CPU intensive, especially for complex systems. As rigorous optimization routines involve repetitive EM simulations, the associated cost may be significant....
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A spline-based FE approach to modelling of high frequency dynamics of 1-D structures
PublicationIn this paper a computational methodology leading to the development of a new class of FEs, based on the application of continuous and smooth approximation polynomials, being splines, has been presented. Application of the splines as appropriately defined piecewise elemental shape functions led the authors to the formulation of a new approach for FEM, named as spFEM, where contrary to the well-known NURBS approach, the boundaries...
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Damage location in beam and plate structures by wavelet analysis of experimentally determined mode shapes
PublicationArtykuł dotyczy zastosowania analizy falkowej do lokalizacji uszkodzeń w konstrukcjach belkowych i płytowych. Wykonano testy dynamiczne belki wspornikowej i płyty utwierdzonej wzdłuż jednej z krawędzi. Lokalizację defektu otrzymano za pomocą transformaty falkowej eksperymentalnie wyznaczonych postaci drgań.
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Victor Eremeev prof. dr hab.
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Effect of different crystalline structures on W/O and O/W/O wax emulsion stability
PublicationtThe possibility of emulsion stabilization using mineral and vegetable wax particles only (without sur-factant) was investigated. Mineral waxes, paraffin wax and ceresin, and a vegetable wax, carnauba wax,were used. The content of the wax particles and the water to oil proportion were found crucial for thestability of all emulsions. Some emulsions were also produced with a liquid wax (i.e. jojoba oil). Themultiple light scattering...
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Influence of separation gap on the response of colliding models of steel structures under seismic and paraseismic excitations
PublicationAs a result of high urbanization, the need to erect closely-spaced buildings forces designers to consider collisions between structures taking place during ground motions. Experimental and numerical studies have confirmed that such collisions (often referred to as structural pounding) may cause serious damage to the structural elements and even lead to total collapse of colliding structures. The main reason of earthquake-induced...
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Non-destructive testing of industrial structures with the use of multi-camera Digital Image Correlation method
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New Coordination Polymers of Selected Lanthanides with 1,2-Phenylenediacetate Linker: Structures, Thermal and Luminescence Properties
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New D−π–D−π–A Systems Based on Phenothiazine Derivatives with Imidazole Structures for Photovoltaics
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Modeling of the L and M x-ray line structures for tungsten in high-temperature tokamak plasmas
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Damage detection strategies for aircraft shell-like structures based on propagation guided elastic waves
PublicationW pracy przedstawiono mozliwości detekcji uszkodzeń w lotniczych konstrukcjach powłokowych z wykorzystaniem fal sprężystych. Omówiono kilka strategii detekcji uszkodzeń. Przedstawiono wyniki symulacji numerycznych z wykorzystaniem metody spektralnych elementów skończonych, jak również wynik badań eksperymentalnych z zastosowaniem wibrometrii laserowej.
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Expedited Multi-Objective Design Optimization of Miniaturized Microwave Structures Using Physics-Based Surrogates
PublicationIn this paper, a methodology for fast multi-objective design optimization of compact microwave circuits is presented. Our approach exploits an equivalent circuit model of the structure under consideration, corrected through implicit and frequency space mapping, then optimized by a multi-objective evolutionary algorithm. The correction/optimization of the surrogate is iterated by design space confinement and segmentation based on...
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CAVER Analyst 1.0: graphic tool for interactive visualization and analysis of tunnels and channels in protein structures
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Prediction of the structures of proteins with the UNRES force field, including dynamic formation and breaking of disulfide bonds
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Nano-particulate Structures with Glucose-Derived Char and Compacted Fumed Silica in Gaseous and Aqueous Media
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Syntheses, Structures and Reactivity of Terminal Phosphido Complexes of Iron(II) Supported by a β-Diketiminato Ligand
PublicationWe report the synthesis of the first series of terminal phosphido iron complexes supported by a β‐diketiminato ligand (Dippnacnac) and their catalytic activity in dehydrocoupling of secondary phosphines. Anionic and neutral mono‐ or diphosphido complexes were obtained from the reaction of [(Dippnacnac)FeCl2Li(dme)2] with the R2PLi (R = iPr, tBu, Cy, Ph) phosphides by tuning the stoichiometric ratio, polarity of the solvent, and...
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Towards Changes of Macro-Economic Structures in Middle Eastern Countries. Empirical Evidence for 1970–2018
PublicationMiddle East countries share a wide bundle of specific structural economic features and one of the latest is a high dependency of these economies on fossil fuels, which is quantitatively demonstrated through the share of oil and gas revenues in total export, but also in gross domestic product composition. This high economic dependency on natural resources on one hand has recently generated a material wealth of Middle Eastern countries...
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Fast EM-driven size reduction of antenna structures by means of adjoint sensitivities and trust regions
PublicationIn this letter, a simple yet robust and computationally efficient optimization technique for explicit size reduction of antenna structures is presented. Our approach directly handles the antenna size as the main design objective, while ensuring satisfactory electrical performance by means of suitably defined penalty functions. For the sake of accuracy, the antenna structure is evaluated using high-fidelity EM simulation. In order...
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Coordination polymers and molecular structures among complexes of mercury(II) halides with selected 1-benzoylthioureas
PublicationSix new 1-benzoyl-3-phenylthiourea and 1-benzoyl-3-(2-methylphenyl)thiourea complexes of mercury( II) were obtained in the reactions of the ligands with HgX2 in methanol (X = Cl, Br, I). Their structures, determined by single-crystal X-ray diffraction analysis, exhibit different stoichiometries and molecular organization. Coordination centers adopt more or less distorted tetrahedral geometry (five structures) or distorted trigonal...
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Composite thermoluminescent detectors based on the Ce3+ doped LuAG/YAG and YAG/LuAG epitaxial structures
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Distortions in structures of the twist bend nematic phase of a bent-core liquid crystal by the electric field
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Quasi-Global Optimization of Antenna Structures Using Principal Components and Affine Subspace-Spanned Surrogates
PublicationParametric optimization is a mandatory step in the design of contemporary antenna structures. Conceptual development can only provide rough initial designs that have to be further tuned, often extensively. Given the topological complexity of modern antennas, the design closure necessarily involves full-wave electromagnetic (EM) simulations and—in many cases—global search procedures. Both factors make antenna optimization a computationally...
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A Flexible Nafion Coated Enzyme‐free Glucose Sensor Based on Au‐dimpled Ti Structures
PublicationThe detection of glucose at low concentrations using electrochemical sensors is of great importance due to the possibility of using different human body fluids than blood, such as e.g. urine, saliva, sweat or tears. The interest behind those biofluids is related to their utility in non-invasive sugar determination. In this work, we present flexible, fully biocompatible electrode material based on Au nanoparticles immobilized onto...
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Electrochemical performance of MOF-5 derived carbon nanocomposites with 1D, 2D and 3D carbon structures
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Low-cost EM-Simulation-based Multi-objective Design Optimization of Miniaturized Microwave Structures
PublicationIn this work, a simple yet reliable technique for fast multi-objective design optimization of miniaturized microwave structures is discussed. The proposed methodology is based on point-by-point identification of a Pareto-optimal set of designs representing the best possible trade-offs between conflicting objectives such as electrical performance parameters as well as the size of the structure of interest. For the sake of computational...
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Buckling analysis of shell structures with stochastic imperfections using six parameter nonlinear shell theory
PublicationPrzedstawiono wpływ wstępnych losowych imperfekcji geometrycznych na wartość obciążenia krytycznego powłoki. W obliczeniach zastosowano autorski program MES wykorzystujący 6-cio parametrową nieliniową teorię powłok.
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Improved selectivity compact band-stop filter with gosper fractal-shaped defected ground structures
PublicationA novel band-stop filter using Gosper fractal-shaped defected ground structures has been designed and manufactured. The improvement in the filter selectivity has been achieved by introducing a multiresonance fractal-shaped defect leading to a higher filter order, simultaneously maintaining its compact size. The experimental results prove the validity of proposed solution and its utility in novel miniaturized and severe requirement...
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Towards mechanosynthesis of diamondoid structures: iv. The strategy for preliminary implementation of elenbogen's ''mater as software'' concept
PublicationOpublikowana wcześniej (Molecular Electronics and Molecular Electronic Devices, Vol. 1, Chap. 2, CRC Press, Inc. 1993, pp. 31-83) strategia budowy molekularnych urządzeń ulektronicznych w oparciu o polisilany jest rozszerzona w kierunku koncepcji Ellenbogena ''mater as software'' poprzez rozważenie użycia zamkniętej jednościennej nanorórki jako ostrza STM w celu umożliwienia manipulacji cząsteczkami sililenu.
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Diagnostics of civil engineering structures with use of continuous fiber optic sensors based on Brillouin scattering
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On dynamics of flexible branched shell structures undergoing large overall motion using finite elements
PublicationZaprezentowano autorski algorytm do analizy dynamicznej powłok sprężystych oparty na niejawnym schemacie Newmarka. Rozważania dotyczą całkowania po czasie dynamicznych równań ruchu sformułowanych w ramach nieliniowej sześcioparametrowej teorii powłok. Opracowanie zawiera pewne elementy analizy statycznej, poprzedzającej badania dynamiczne. Przykłady numeryczne prezentują zastosowanie algorytmu stanowią podstawową część pracy.
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Novel PCSE-based approach of inclined structures geometry analysis on the example of the Leaning Tower of Pisa
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On Accelerated Metaheuristic-Based Electromagnetic-Driven Design Optimization of Antenna Structures Using Response Features
PublicationDevelopment of present-day antenna systems is an intricate and multi-step process requiring, among others, meticulous tuning of designable (mainly geometry) parameters. Concerning the latter, the most reliable approach is rigorous numerical optimization, which tends to be re-source-intensive in terms of computing due to involving full-wave electromagnetic (EM) simu-lations. The cost-related issues are particularly pronounced whenever...
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Crystal structures of eight- and ten-membered cyclic bisanisylphosphonothioyl disulfanes and comparison with their P-ferrocenyl analogues
PublicationTwo new crystal structures of eight- and ten-membered cyclic bisanisylphosphonothioyl disulfanes, namely 2,5-bis(4-methoxyphenyl)-1,6,3,4,25,55- dioxadithiadiphosphocane-2,5-dithione, C16H18O4P2S4, and 2,5-bis(4-methoxyphenyl)-1,6,3,4,25,55-dioxadithiadiphosphecane-2,5-dithione, C18H22O4P2S4, have been determined and compared to structures of the ferrocenyl analogues. The eight-membered rings have similar conformations (TBC) but...
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Bonding in Phosphanylphosphinidene Complexes of Transition Metals and their Correlation with Structures, 31 P NMR Spectra, and Reactivities
PublicationTheoretical studies of the bonding interactions and most important properties are carried out for isolable phosphanylphosphinidene complexes of transition metals. Three main types of phosphanylphosphinidene complexes are distinguished, based on the way in which the phosphanylphosphinidene ligand bonds to the metal center: (i) side-on complexes of platinum, where the R2Pβ–Pα ligand mimics structural features of free singlet phosphanylphosphinidenes...
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Preventing of earthquake-induced pounding between steel structures by using polymer elements – experimental study
PublicationPounding between two, or more, adjacent buildings during earthquakes has been identified as one of the reasons for substantial damage or even total collapse of colliding structures, so it has been the subject of numerous studies in the recent years. A major reason leading to interactions between adjacent, insufficiently separated structures results from the differences in their dynamic properties. A number of different methods...
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Developing Polycentricity to Shape Resilient Metropolitan Structures: The Case of the Gdansk–Gdynia–Sopot Metropolitan Area
PublicationMaking the metropolitan area resilient, in many cases, calls for amending its spatial structures. This may take various forms, including both reshaping the metropolitan core and redeveloping the entire regional network of cities and centres, making them part of a coherent structure. The latter strategy is associated with reinforcing secondary urban centres as well as shaping new connections between them. In this case, the term...
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Theoretical and experimental analysis of guided wave propagation in plate-like structures with sinusoidal thickness variations
PublicationGuided waves have attracted significant attention for non-destructive testing (NDT) and structural health monitoring (SHM) due to their ability to travel relatively long distances without significant energy loss combined with their sensitivity to even small defects. Therefore, they are commonly used in damage detection and localization applications. The main idea of incorporating guided waves in NDT and SHM is based on processing...