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Search results for: METROPOLITAN SPATIAL STRUCTURES
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Hybrid Finite Element Method Development for Offshore Structures’ Calculation with the Implementation of Industry Standards
PublicationIn the design process of offshore steel structures, it is typical to employ commercial calculation codes in which simulation and evaluation of results are performed on the basis of the available standards (e.g. API, DNV, Lloyds). The modeling and solution rely on finite element methods and cover the simulation of the structure’s properties along with the influence of the marine environment – sea currents, wave and wind loading,...
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Tolerance Optimization of Antenna Structures by Means of Response Feature Surrogates
PublicationFabrication tolerances and other types of uncertainties, e.g., the lack of precise knowledge of material parameters, have detrimental effects on electrical and field performance of antenna systems. In the case of input characteristics these are particularly noticeable for narrow- and multi-band antennas where deviations of geometry parameters from their nominal values lead to frequency shifts of the operating frequency bands. Improving...
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Measurement report: Spatial variations in ionic chemistry and water-stable isotopes in the snowpack on glaciers across Svalbard during the 2015–2016 snow accumulation season
PublicationThe Svalbard archipelago, located at the Arctic sea-ice edge between 74 and 81∘ N, is ∼60 % covered by glaciers. The region experiences rapid variations in atmospheric flow during the snow season (from late September to May) and can be affected by air advected from both lower and higher latitudes, which likely impact the chemical composition of snowfall. While long-term changes in Svalbard snow chemistry have been documented in...
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Analysis of graphene multi-strip planar guiding structures with the use of spectral domain approach
PublicationSpectral domain approach is modified and used to analyze some simple structures containing graphene strips. The modification is simple and concerns the Green’s function only. Moreover, the method is combined with the recently published root finding algorithms, which significantly improve the efficiency of the analysis. The results obtained for a simple guiding structure is verified and the field displacement effect is confirmed.
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Efficient model order reduction for FEM analysis of waveguide structures and resonators
PublicationAn efficient model order reduction method for three-dimensional Finite Element Method (FEM) analysis of waveguide structures is proposed. The method is based on the Efficient Modal Order Reduction (ENOR) algorithm for creating macro-elements in cascaded subdomains. The resulting macro-elements are represented by very compact submatrices, leading to significant reduction of the overall number of unknowns. The efficiency of the model...
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Modeling of the M X-ray line structures for tungsten and L X-ray line structures for molybdenum
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Slow-wave resonant structures in branch-line coupler miniaturization: a case study
PublicationA case study of novel slow-wave resonant structures dedicated to efficient microstrip branch-line coupler size reduction has been presented. A compact 3-dB branch-line coupler has been designed to mimic the performance of its conventional counterpart, simultaneously demonstrating a substantial 88% surface area reduction. The vital usefulness of the approach in the process of microstrip line abbreviation has been experimentally...
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Silver complexes stabilized by large silanethiolate ligands – crystal structures and luminescence properties
PublicationBulky silanethiolate and disiladithiolate ligands were applied to synthesize one mononuclear and three trinuclear silver complexes including two cyclic “microclusters” and a linear tri-nuclear silanethiolate complex. All obtained compounds are characterized by X-ray diffraction and FT-IR. NMR and emission spectroscopies were used where possible. The first trinuclear anionic silver thiolate is structurally characterized. The influence...
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Computationally Efficient Design Optimization of Compact Microwave and Antenna Structures
PublicationMiniaturization is one of the important concerns of contemporary wireless communication systems, especially regarding their passive microwave components, such as filters, couplers, power dividers, etc., as well as antennas. It is also very challenging, because adequate performance evaluation of such components requires full-wave electromagnetic (EM) simulation, which is computationally expensive. Although high-fidelity EM analysis...
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Crystal and electronic structures of Ni(II) silanethiolates containing flexible diamine ligands
PublicationFive nickel(II) complexes containing aliphatic diamines and tri-tert-butoxysilanethiolate ligand have been synthesized for the purpose of studying their structural, spectral (IR, UV–Vis, HF EPR) and thermal properties. Complexes (1)–(5) have been prepared in high yield by reactions of [Ni{SSi(OtBu)3}2(NH3)(H2O)] with 1.3-propanediamine (L1), 1,6-hexanediamine (L2), or 1,7-heptanediamine (L3). The X-ray structures were determined...
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Spatial Differences in the Chemical Composition of Surface Water in the Hornsund Fjord Area: A Statistical Analysis with A Focus on Local Pollution Sources
PublicationSurface catchments in Svalbard are sensitive to external pollution, and yet what is frequently considered external contamination may originate from local sources and natural processes. In this work, we analyze the chemical composition of surface waters in the catchments surrounding the Polish Polar Station in Svalbard, Hornsund fjord area. We have pooled unpublished and already published data describing surface water composition...
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DEM investigations of two-dimensional granular vortex- and anti-vortex- structures during plane strain compression.
PublicationDEM investigations of two-dimensional granular vortex- and anti-vortex- structures during plane strain compression.
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Hybrid Finite Element Method Development for Offshore Structures’ Calculation with the Implementation of Industry Standards
PublicationIn the design process of offshore steel structures, it is typical to employ commercial calculation codes in which simulationand evaluation of results are performed on the basis of the available standards (e.g. API, DNV, Lloyds). The modelingand solution rely on finite element methods and cover the simulation of the structure’s properties along with the influenceof the marine environment – sea currents, wave...
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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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Methodology for the Correction of the Spatial Orientation Angles of the Unmanned Aerial Vehicle Using Real Time GNSS, a Shoreline Image and an Electronic Navigational Chart
PublicationUndoubtedly, Low-Altitude Unmanned Aerial Vehicles (UAVs) are becoming more common in marine applications. Equipped with a Global Navigation Satellite System (GNSS) Real-Time Kinematic (RTK) receiver for highly accurate positioning, they perform camera and Light Detection and Ranging (LiDAR) measurements. Unfortunately, these measurements may still be subject to large errors-mainly due to the inaccuracy of measurement of the optical...
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Monitoring of metal structures with the dynamic methods
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Unusual structures of Mg2F5- superhalogen anion
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Simulation and identification of damage in bar structures.
PublicationPraca zawiera opis i testy 3 procedur badawczych dotyczących lokalizacjizniszczeń w konstrukcjach. Procedury bazują na danych modalnych jakie obiektgeneruje podczas swoich drgań tzn. częstościach własnych i postaciach drgań Badane są zmiany podatności układu, zmiany krzywizn postaci drgań i wrażli-wość częstości na założone zniszczenia. Odpowiednie procedury wiążące się ztymi trzema metodami są przestestowane na przykładzie wspornika...
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Development of quay structures for container harbour .
PublicationPrace poświęcono nowym rozwiązaniom konstrukcyjnym nabrzeży przeznaczonym do przeładunku kontenerów. Zwrócono przy tym głównie uwagę na spełnienie warunków stateczności w przypadku występowania dużych prędkości strumieni zaśrubowych wywołanych napędami statków podczas ich manewrowania.
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Strengthening of structures by shock transmission units.
PublicationCelem niniejszego artykułu jest analiza możliwości zastosowania tzw. przenośników drgań do wzmacniania konstrukcji budowlanych (w tym mostowych) narażonych na oddziaływania dynamiczne takie jak: wiatr, siły hamowania pojazdów czy trzęsienia ziemi.
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Geodesic monitoring of tower and mast structures
PublicationW artykule przedstawiono obciążenia jakim są poddawane konstrukcje wieżowe i masztowe. Opisano zakres oraz wymagania dotyczące pomiarów geodezyjnych przeprowadzanych w czasie eksploatacji konstrukcji smukłych. Wskazano metody pomiaru oraz zaprezentowano niektóre sposoby pomiaru w praktyce. Zamieszczono wyniki pomiarów przemieszczeń elektrowni wiatrowej o mocy 2 MW i wysokości elementu wsporczego 80 m oraz zaprezentowano pomiary...
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Structural Dynamics and Stability of Composite Structures
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Selected problems of stability of steel structures.
PublicationW pracy przedstawiono wyniki badań dotyczących stateczności wybranych konstrukcji stalowych. Prezentowane rozważania są oparte na klasycznych założeniach teorii prętów cienkościennych o nieodkształcalnym przekroju poprzecznym. Wyznaczono pierwszą wariację sił krytycznych pręta cienkościennego o bisymetrycznym otwartym przekroju poprzecznym uwzględniając następujące zmienne projektowe: ⎯wymiary przekroju poprzecznego, ⎯ charakterystyki...
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Geosynthetics tests in hydrotechnical structures design
PublicationW celu właściwego stosowania w konstrukcjach budowlanych (w tym również hydrotechnicznych)geosyntetyków - zarówno przepuszczalnych (geotekstylia i wyroby pokrewne) jak i nieprzepuszaczalnych (geomembrany i kompozyty uszczelniające), bardzo ważne jest wcześniejsze poddawanie go odpowiednim badaniom, których procedura musi być ściśle powiązana z późniejszym przeznaczeniem geomateriału i uwzględniać warunki, w jakich materiał będzie...
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Modal diagnostics of civil engineering structures.
PublicationKsiążka dotyczy zastosowania analizy modalnej do diagnostyki konstrukcji budowlanych.
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Seismic probabilistic assessment of steel and reinforced concrete structures including earthquake-induced pounding
PublicationRecent earthquakes demonstrate that prioritizing the retrofitting of buildings should be of the utmost importance for enhancing the seismic resilience and structural integrity of urban structures. To have a realistic results of the pounding effects in modeling process of retrofitting buildings, the present research provides seismic Probability Factors (PFs), which can be used for estimating collision effects without engaging in...
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Topological modifications for performance improvement and size reduction of wideband antenna structures
PublicationCompact antennas belong to the key components of modern communication systems. Their miniaturization is often achieved by introducing appropriate topological changes such as simple ground plane slots or tapered feeds. More sophisticated modifications are rarely considered in the literature because they normally lead to significant increase of the number of tunable parameters, which makes the antenna design process more challenging....
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Advanced Control Structures of Turbo Generator System of Nuclear Power Plant
PublicationIn the paper a synthesis of advanced control structures of turbine and synchronous generator for nuclear power plant working under changing operating conditions (supplied power level) is presented. It is based on the nonlinear models of the steam turbine and synchronous generator cooperating with the power system. Considered control structure consists of multi-regional fuzzy control systems with local linear controllers, including...
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Advanced Control Structures of Turbo Generator System of Nuclear Power Plant
PublicationIn the paper a synthesis of advanced control structures of turbine and synchronous generator for nuclear power plant working under changing operating conditions (supplied power level) is presented. It is based on the nonlinear models of the steam turbine and synchronous generator cooperating with the power system. Considered control structure consists of multi-regional fuzzy control systems with local linear controllers, including...
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On Reduced-Cost Design-Oriented Constrained Surrogate Modeling of Antenna Structures
PublicationDesign of contemporary antenna structures heavily relies on full-wave electromagnetic (EM) simulation models. Such models are essential to ensure reliability of evaluating antenna characteristics, yet, they are computationally expensive and therefore unsuitable for handling tasks that require multiple analyses, e.g., parametric optimization. The cost issue can be alleviated by using fast surrogate models. Conventional data-driven...
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Crystal structures of aminotransferases Aro8 and Aro9 from Candida albicans and structural insights into their properties
PublicationAminotransferases catalyze reversibly the transamination reaction by a ping-pong bi-bi mechanism with pyridoxal 5′-phosphate (PLP) as a cofactor. Various aminotransferases acting on a range of substrates have been reported. Aromatic transaminases are able to catalyze the transamination reaction with both aromatic and acidic substrates. Two aminotransferases from C. albicans, Aro8p and Aro9p, have been identified recently, exhibiting...
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Particle Shape Effect on Macroscopic Behaviour of Underground Structures: Numerical and Experimental Study
PublicationThe mechanical performance of underground flexible structures such as buried pipes or culverts made of plastics depend not only on the properties of the structure, but also the material surrounding it. Flexible drains can deflect by 30% with the joints staying tight, or even invert. Large deformations of the structure are difficult to model in the framework of Finite Element Method, but straightforward in Discrete Element Methods....
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Particle Shape Effect on Macroscopic Behaviour of Underground Structures: Numerical and Experimental Study
PublicationAbstract: The mechanical performance of underground flexible structures such as buried pipes or culverts made of plastics depend not only on the properties of the structure, but also on the material surrounding it. Flexible drains can deflect by 30% with the joints staying tight, or even invert. Large deformations of the structure are difficult to model in the framework of Finite Element Method, but straightforward in Discrete...
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Pareto Ranking Bisection Algorithm for Expedited Multi-Objective Optimization of Antenna Structures
PublicationThe purpose of this letter is introduction of a novel methodology for expedited multi-objective design of antenna structures. The key component of the presented approach is fast identification of the initial representation of the Pareto front (i.e., a set of design representing the best possible trade-offs between conflicting objectives) using a Pareto-ranking bisection algorithm. The algorithm finds a discrete set of Pareto-optimal...
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Accelerated Re-Design of Antenna Structures Using Sensitivity-Based Inverse Surrogates
PublicationThe paper proposes a novel framework for accelerated re-design (dimension scaling) of antenna structures using inverse surrogates. The major contribution of the work is a sensitivity-based model identification procedure, which permits a significant reduction of the number of reference designs required to render the surrogate. Rigorous formulation of the approach is supplemented by its comprehensive numerical validation using a...
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Chitin and derivative chitosan-based structures — Preparation strategies aided by deep eutectic solvents: A review
PublicationThe 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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Recent Advances in Performance-Driven Surrogate Modeling of High-Frequency Structures
PublicationDesign 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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Application of Shape Memory Alloys in Retrofitting of Masonry and Heritage Structures Based on Their Vulnerability Revealed in the Bam 2003 Earthquake
PublicationFor decades, one of the most critical considerations of civil engineers has been the construction of structures that can sufficiently resist earthquakes. However, in many parts of the globe, ancient and contemporary buildings were constructed without regard for engineering; thus, there is a rising necessity to adapt existing structures to avoid accidents and preserve historical artefacts. There are various techniques for retrofitting...
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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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The Revitalization Processes of the Port Structures in Gdynia and Gdansk on the Background of Contemporary Port Changes
PublicationTransformations of the port facilities against the modernization of the port structures are present in many city-port centers since more than 50 years. The modernization taking place in the ports located in Gdynia-Gdansk mainly concerns communication availability and adapted to the multimodal technology of transport and transshipment. Developing specialized tech-terminals serving a specific type of load, causes development of the...
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High-Efficacy Global Optimization of Antenna Structures by Means of Simplex-Based Predictors
PublicationDesign of modern antenna systems has become highly dependent on computational tools, especially full-wave electromagnetic (EM) simulation models. EM analysis is capable of yielding accurate representation of antenna characteristics at the expense of considerable evaluation time. Consequently, execution of simulation-driven design procedures (optimization, statistical analysis, multi-criterial design) is severely hindered by the...
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Influence of pitting corrosion on fatigue and corrosion fatigue of ship structures. Part I: pitting corrosion of ship structures.
PublicationThe paper is a literature survey focused on pitting corrosion and its influence on fatigue of ship and offshore steels. Mechanisms of short- and long-term pitting corrosion in marine environment have been described including pit nucleation and growth phases. Some models of pit growth versus time of exposure have been presented. Some factors which influence the pit growth have been discussed briefly.
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Transmission Losses Spatial Analysis of the Supply System of Electrified Urban Transport Network
PublicationThe paper presents mathematical model TOPSIS which was applied for MCDA benchmark of trolleybus supply system. Moreover, paper presents the novel method of transmission losses analysis in electrified urban transport system. Research work was based on measurements realized in Gdynia trolleybus network.
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Spatial Analysis of Water Infrastructure Development On Example of Eastern Europe Rural Regions
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Spatial and interannual variations of seasonal sea surface temperature patterns in the Baltic Sea
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Spatial diversity of tourist function development: the municipalities of Poland’s West Pomerania province
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Seasonal and spatial variation of the Montagu’s Harrier’s Circus pygargus diet in Eastern Poland
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The analysis of the accuracy of spatial models using photogrammetric software: Agisoft Photoscan and Pix4D
PublicationThis article was created as a result of research conducted within the master thesis. The purpose of the measurements was to analyze the accuracy of the positioning of points by computer programs. Selected software was a specialized computer software dedicated to photogrammetric work. For comparative purposes it was decided to use tools with similar functionality. As the basic parameters that affect the results selected the resolution...
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3d point-cloud spatial expansion by total least-squares line fitting
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Assessing historical church tower asymmetry using point cloud spatial expansion
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