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Wyniki wyszukiwania dla: NONCENTROSYMMETRIC STRUCTURES
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Syntheses, Structures and Reactivity of Terminal Phosphido Complexes of Iron(II) Supported by a β-Diketiminato Ligand
PublikacjaWe 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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Preventing of earthquake-induced pounding between steel structures by using polymer elements – experimental study
PublikacjaPounding 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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Non-Linear Analysis of Structures Utilizing Load-Discretization of Stiffness Matrix Method with Coordinate Update
PublikacjaThis paper proposes a stiffness method based structural analysis algorithm for geometrically non-linear structures. In this study, the applied load on the joints has been discretized to a sequence of a few loadings applied. Each loading step produces incremental external nodal displacements, which are added to the corresponding coordinates to get a new geometrical shape of the structure. This process is iteratively repeated until...
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Design-oriented modeling of antenna structures by means of two-level kriging with explicit dimensionality reduction
PublikacjaThe employment of full-wave electromagnetic (EM) analysis is a practical necessity in the design of contemporary antenna structures. This is because simpler models are generally not available or of limited accuracy. At the same time, EM-based design is computationally expensive. Consequently, the ways of accelerating tasks such as parametric optimization or uncertainty quantification have to be sought. A possible workaround that...
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On Fast Multi-objective Optimization of Antenna Structures Using Pareto Front Triangulation and Inverse Surrogates
PublikacjaDesign of contemporary antenna systems is a challenging endeavor, where conceptual developments and initial parametric studies, interleaved with topology evolution, are followed by a meticulous adjustment of the structure dimensions. The latter is necessary to boost the antenna performance as much as possible, and often requires handling several and often conflicting objectives, pertinent to both electrical and field properties...
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Closer look into the structures of tetrabutylammonium bromide–glycerol-based deep eutectic solvents and their mixtures with water
PublikacjaIn recent years, deep eutectic solvents (DES) and it’s mixture with water have become more and more attention as green solvents used in chemistry. However, there are only a few theoretical studies on the mechanisms of pure DES and DES-water complex formation. Therefore, the structural properties of tetrabutylammonium bromide–glycerol-based deep eutectic solvents and their mixtures with water have been investigated by means of Molecular...
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Shaking table experimental study on pounding between adjacent structures founded on different soil types
PublikacjaThe aim of this study is to extensively investigate the effect of the soil type on the response of colliding structures based on shaking table experimental tests. Two single-storey models of steel buildings with different dynamic parameters were considered in this study. Three pounding scenarios were taken into account by applying different seismic gaps (0.5 cm, 1 cm and 1.5 cm as well as the no pounding case). First, the effect...
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Developing Polycentricity to Shape Resilient Metropolitan Structures: The Case of the Gdansk–Gdynia–Sopot Metropolitan Area
PublikacjaMaking 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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A Flexible Nafion Coated Enzyme‐free Glucose Sensor Based on Au‐dimpled Ti Structures
PublikacjaThe 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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Quasi-Global Optimization of Antenna Structures Using Principal Components and Affine Subspace-Spanned Surrogates
PublikacjaParametric 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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Theoretical and experimental analysis of guided wave propagation in plate-like structures with sinusoidal thickness variations
PublikacjaGuided 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...
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Crack Detection in Metallic Surfaces Based on Dumbbell-Shaped Defected Ground Structures in Microstrip Technology
PublikacjaIn this paper, a novel crack detection sensor using a microstrip loaded with a Dumbbell-Shaped Defected Ground Structure (DS-DGS) is proposed. The sensing element is etched in the ground plane of a microstrip line and it is easy to fabricate. The electromagnetic (EM) field of the microstrip couples to the DS-DGS, thus demonstrating a bandstop behavior. It is shown that in the presence of a crack in a metallic surface underneath the...
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Fast multi-objective optimization of antenna structures by means of data-driven surrogates and dimensionality reduction
PublikacjaDesign of contemporary antenna structures needs to account for several and often conflicting objectives. These are pertinent to both electrical and field properties of the antenna but also its geometry (e.g., footprint minimization). For practical reasons, especially to facilitate efficient optimization, single-objective formulations are most often employed, through either a priori preference articulation, objective aggregation,...
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Sub-national structures matter when evaluating physical activity promotion: Lessons from Germany
PublikacjaBackground Public policies are increasingly acknowledged as important part of promoting physical activity (PA). However, especially in states with sub-national administrative structures such as Germany, national and sub-national approaches differ considerably. In Germany, sport for all (SfA) promotion is mostly organized at sub-national level, which is usually not covered in national evaluations. Knowledge of these structures helps...
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Towards Changes of Macro-Economic Structures in Middle Eastern Countries. Empirical Evidence for 1970–2018
PublikacjaMiddle 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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Cost-Efficient EM-Driven Size Reduction of Antenna Structures by Multi-Fidelity Simulation Models
PublikacjaDesign of antenna systems for emerging application areas such as the Internet of Things (IoT), fifth generation wireless communications (5G), or remote sensing, is a challenging endeavor. In addition to meeting stringent performance specifications concerning electrical and field properties, the structure has to maintain small physical dimensions. The latter normally requires searching for trade-off solutions because miniaturization...
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SENSITIVITY ANALYSIS IN THE REHABILITATION OF HISTORIC TIMBER STRUCTURES ON THE EXAMPLES OF GREEK CATHOLIC CHURCHES IN POLISH SUBCARPATHIA
PublikacjaThis work concerns structural and sensitivity analysis of carpentry joints used in historic wooden buildings in south-eastern Poland and western Ukraine. These are primarily sacred buildings and the types of joints characteristic for this region are saddle notch and dovetail joints. Thus, in the study the authors focus on these types of corner log joints. Numerical models of the joints are defined and finite element simulations...
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Chitin and derivative chitosan-based structures — Preparation strategies aided by deep eutectic solvents: A review
PublikacjaThe high molecular weight of chitin, as a biopolymer, challenges its extraction due to its insolubility in the solvents. Also, chitosan, as the N-deacetylated form of chitin, can be employed as a primary material for different industries. The low mechanical stability and poor plasticity of chitosan films, as a result of incompatible interaction between chitosan and the used solvent, have limited its industrialization. Deep eutectic...
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Low-cost EM-Simulation-based Multi-objective Design Optimization of Miniaturized Microwave Structures
PublikacjaIn 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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Investigations of vortex-structures in granular bodies based on DEM and Helmholtz-Hodge flow field decomposition
PublikacjaArtykuł omawia wyniki numeryczne dotyczące struktur wirowych w materiałach granulowanych. Obliczenia wykonano dla stanu pasywnego przemieszczającej się sztywnej ścianki. W symulacjach wykorzystano metodę elementów dyskretnych i dekompozycję Helmholtza/Hodge’a pola prędkości. Struktury wirowe okazały się znakomitym prekursorem lokalizacji odkształceń stycznych w materiałach granulowanych.
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Ahmed Manguri PhD Student
OsobyJestem doktorantem I roku na Politechnice Gdańskiej w zakresie Dynamicznej Analizy Konstrukcji pod kierunkiem prof. Jankowskiego. Ukończyłem studia magisterskie z inżynierii strukturalnej na Uniwersytecie Cardiff w Wielkiej Brytanii oraz licencjat z inżynierii lądowej na Uniwersytecie Koya w Kurdystanie. Od 2016 roku jestem pracownikiem naukowym Uniwersytetu Raparin w Kurdytanie.
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On the relationship between the structural and volumetric properties of solvated metal ions in O-donor solvents using new structural data in amide solvents
PublikacjaThe structures of the N,N-dimethylformamide (dmf), N,N-dimethylacetamide (dma), and N,N-dimethylpropionamide (dmp) solvated strontium and barium ions have been determined in solution using large angle X-ray scattering and EXAFS spectroscopy. The strontium ion has a mean coordination number (CN) between 6.2 and 6.8, and the barium ion has a mean CN between 7.1 and 7.8 in these amide solvents. The non-integer numbers indicates that...
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Foundations of Software Science and Computational Structures
Konferencje -
Opir Materialiv i Teoria Sporud-Strength of Materials and Theory of Structures
Czasopisma -
A Review: Structural Shape and Stress Control Techniques and their Applications
PublikacjaThis review article presents prior studies on controlling shape and stress in flexible structures. The study offers a comprehensive survey of literature concerning the adjustment and regulation of shape, stress, or both in structures and emphasizes such control’s importance. The control of systems is classified into three primary classes: nodal movement control, axial force control, and controlling the two classes concurrently....
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Electrical and structural properties of Nb-doped SrTiO3 ceramics
PublikacjaPrzebadano wpływ zawartości niobu na strukturę i własności elektryczne tytanianu strontu. Zbadany został wpływ warunków redukcji i porowatości na właściwości materiału. Za optymalne uznano domieszkowanie niobem w wysokości 2% molowych.
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Structural and Electrical Properties of STF Materials for SOFC Applications
PublikacjaW tym artykule przedstawiono badania tytanian strontu domieszkowanego żelazem. Synteza dwuetapowa była niezbędna do uzyskania czystego fazowo proszku o pożądanych właściwościach. Przewodnictwo elektryczne wykazało właściwości typu zero-TCR dla składu STF35. Poziom przewodnictwa elektrycznego różnił się o więcej niż jeden rząd wartości dla wytworzonych materiałów. Reaktywność chemiczną między YSZ i STF badano w zakresie temperatur...
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Structural and magnetic properties of Cu-alloyed FePd films
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Structural analysis and predicting effects of natural mutations on telomerase
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Nanometer structural columns and frustration of magnetic ordering inNb12O29
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Structural properties of superconducting PrBa2Cu3O7−δ single crystals
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Application of structural dynamic methods in diagnosis of historic buildings
PublikacjaPraca prezentuje różnego rodzaju badania diagnostyczne wykonane dla dwóch obiektów historycznych. Analizy oparto na drganiach budowli pomierzonych podczas wymuszeń środowiskowych. Opisano sposób identyfikacji parametrów modalnych przy zastosowaniu teorii korelacyjnej, przykładową metodologię określania parametrów posadowienia oraz wykrywania uszkodzeń w konstrukcjach. Zaprezentowano wyniki otrzymane dla badanych obiektów wraz...
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Structural stability of invariant sets of vibro-impact systems
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Towards homoscedastic nonlinear cointegration for structural health monitoring
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Hydrogen degradation of structural steels in technical hydrocarbon liquids
PublikacjaDla stali stopowych przeprowadzono badania absorpcji wodoru, mechaniczno-korozyjne przy stałej małej prędkości odkształcania, przy stałym obciążeniu i przy obciążeniu cyklicznie-zmiennym. Środowiskiem było paliwo kotłowe, przepracowany olej mineralny oraz gliceryna. Stwierdzono, iż pochłonięty wodór nie powoduje przedwczesnego zniszczenia stali poddanych działaniu stałego obciążenia ponizej granicy plastyczności oraz, że zaabsorbowany...
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Two-particle entropy and structural ordering in liquid water
PublikacjaEntropies of simple point charge (SPC) water were calculated over the temperature range 278-363 K using the two-particle correlation function approximation. Then, the total two-particle contribution to the entropy of the system was divided into three parts, which we call translational, configurational, and orientational. The configurational term describes the contribution to entropy, which originates from spatial distribution of...
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Structural pounding models with Hertz spring and nonlinear damper
PublikacjaW artykule przedstawiono porównanie możliwości wykorzystania dwóch modeli zderzeń: nieliniowego modelu lepkosprężystego i modelu Hertz'a z dodatkowym tłumieniem. Efektywność każdego z modeli zbadano porównując wyniki analiz numerycznych z wynikami badań eksperymentalnych. Wyniki pracy pokazują, iż zastosowanie nieliniowego modelu lepkosprężystego prowadzi do mniejszych błędów w przebiegach czasowych siły zderzenia oraz do mniejszych...
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Elastic wave propagation software in structural health monitoring
PublikacjaW pracy omówiono program do analizy propagacji fal spręzytsych w lementach konstrukcji z uszkodzeniami, oraz omówiono mozliwości jego wykorzystania do monitorowania stanu konstrukcji.
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A Review: Structural Shape and Stress Control Techniques and their Applications
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Building damage due to structural pounding during earthquakes
PublikacjaEarthquake-induced pounding between adjacent buildings has been identified as one of the reasons for substantial damage or even total collapse of colliding structures. A major reason leading to interactions in buildings results from the differences in their dynamic parameters and also from insufficient distance between the structures. Although the research on structural pounding has been much advanced, the studies have mainly been...
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Structural and spectroscopic analysis of a new family of monomeric diphosphinoboranes
PublikacjaWe present a series of amino- and aryl(diphosphino)boranes R2PB(R’’)PR’2, where R2P, R’2P = tBu2P, tBuPhP, Ph2P, Cy2P, and R’’ = iPr2N, Ph, which were obtained via the metathesis reaction of iPr2NBBr2 or PhBBr2 with selected lithium phosphides. The structures of isolated diphosphinoboranes were characterized in the solid state and in solution by means of X-ray diffraction and NMR spectroscopy, respectively. The utility of these...
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SYNTHESIS AND STRUCTURAL CHARACTERIZATION OF NIOBIUM-DOPED HYDROXYAPATITE CERAMICS
PublikacjaHydroxyapatite (HAp) ceramic materials are considered as one of the most promising implant materials in bone surgery and in dentistry. They exhibit unique biocompatibility, bioactivity, and osteoconductivity, which are the most desirable biomaterial features. However, HAp itself is brittle, has low strength, high degree of crystallinity and low solubility at physiological pH. Doping synthetic HAp with metal ions plays an important...
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Intelligent Material Actuators and Their Applications for Structural Dynamic Control
PublikacjaThe paper presents an application of inteligent materials to vibration control of structures.
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Praseodymium substituted lanthanum orthoniobate: Electrical and structural properties
PublikacjaThe results of ionic transport and structural measurements for the lanthanum orthoniobate doped by praseodymium are presented and discussed. The influence of calcium co-doping on these properties has also been analyzed. The results suggest the predominant protonic conductivity for the investigated system in the whole range of investigated temperatures. The influence of calcium co-doping on phase purity is analyzed.
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Structural and electrical properties of titanium-doped yttrium niobate
PublikacjaIn this work, the influence of the substitution of niobium by titanium in Y3Nb1-xTixO7-δ on the structural and electrical properties is reported. Several experimental techniques, i.e. X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), X-Ray Photoelectron Spectroscopy (XPS) and Electrochemical Impedance Spectroscopy (EIS), were applied to investigate the system Y3Nb1-xTixO7-δ. Titanium in Y3Nb1-xTixO7-δ is an acceptor-type...
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Structural changes in the polish economy- the analysis of input-output
Publikacjathis paper analyses the structure of polish economy using three input-output tables for years 1995, 2000 and 2004. applying the traditional methods proposed by rasmussen the sector's backward and forward linkages are identified. industries with large backward and forward linkages are named "key sectors" and play an important role in the development strategy of a country, so the outcome of the paper may be used for the development...
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The effectiveness of polymer adhesive in reduction of vibrations of structural members
PublikacjaIn this paper, the idea of using polymer adhesive as a damping layer is proposed. An experimental study of two aluminium cantilevered beams has been conducted. One of them presents a plain cantilevered beam, while the second one considers two aluminium beams bonded with a polymer adhesive of different thickness (0,5; 1,2; 1,75; 3,1 and 5 mm). The polymer adhesive considered in the study is a specially designed flexible...
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GROWTH AND STRUCTURAL CHANGES IN TRANSITION COUNTRIES: THE CHICKEN OR THE EGG?
PublikacjaThe objective of this study is to test empirically the relationship between structural changes (changes in gross value added and employment) and economic growth. We used a panel Granger-causality analysis based on annual data for eight transition countries, covering the period 1995–2011. The main finding is that the causality relations analysed are heterogeneous processes and are identified more often...
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Terbium Substituted Lanthanum Orthoniobate: Electrical and Structural Properties
PublikacjaThe results of electrical conductivity studies, structural measurements and thermogravimetric analysis of La1−xTbxNbO4+δ (x = 0.00, 0.05, 0.1, 0.15, 0.2, 0.3) are presented and discussed. The phase transition temperatures, measured by high-temperature x-ray diffraction, were 480 °C, 500 °C, and 530 °C for La0.9Tb0.1NbO4+δ, La0.8Tb0.2NbO4+δ, and La0.7Tb0.3NbO4+δ, respectively. The impedance spectroscopy results suggest mixed conductivity...
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Impact of thermal loading into the structural performance of ships: A review
PublikacjaThe presented study reviews the recent advances done regarding the impact of thermal loading on the structural performance of ships. Firstly, the studies related to the mechanical and thermal properties of typical materials used in shipbuilding are outlined. Secondly, a brief introduction to the heat transfer analysis, Finite Element modelling and thermal stresses is provided. Finally, the review of papers dealing with the structural...