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Search results for: PROPAGATION IN THE SHALLOW SEA
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Evaluation of propagation parameters of open guiding structures with the use of complex root finding algorithms
PublicationAn efficient complex root tracing algorithm is utilized for the investigation of electromagnetic wave propagation in open guiding structures. The dispersion characteristics of propagated and leaky waves are calculated for a couple of chosen waveguides. The efficiency of the root tracing algorithm is discuses and compared to a global root finding algorithm.
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Numerical and experimental investigation of guided ultrasonic wave propagation in non-uniform plates with structural phase variations
PublicationThe article presents the results of numerical and experimental investigations of guided wave propagation in aluminum plates with variable thickness. The shapes of plate surfaces have been specially designed and manufactured using a CNC milling machine. The shapes of the plates were defined by sinusoidal functions varying in phase shift, which forced the changes in thickness variability alongside the propagation path. The main aim...
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Smart Asset Management for District Heating Systems in the Baltic Sea Region.
PublicationThe purpose of this review is to provide insight and a comparison of the current status of district heating (DH) systems for selected Baltic Sea countries (Denmark, Germany, Finland, Latvia, Lithuania, Poland, and Sweden), especially from viewpoints of application and solutions of novel smart asset management (SAM) approaches. Furthermore, this paper considers European projects ongoing from 2016, involving participants from the...
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Propagation Characteristics of Partial Discharges in an Oil-Filled Power Transformer
PublicationPower transformers are among the most important assets in the power transmission and distribution grid. However, they suffer from degradation and possible faults causing major electrical and financial losses. Partial discharges (PDs) are used to identify the insulation health status and their degradation level. PDs are incipient, low-magnitude faults caused by localized dielectric breakdown. Those activities emit signals in many...
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44 Years Hindcast of the sea level and circulation in the Baltic Sea
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Numerical modelling of thermodynamics and dynamics of sea ice in the Baltic Sea
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Wave propagation in delaminated beam
PublicationW pracy przedstawiono model oraz wyniki analizy propagacji fali sprezystejw belce z delaminacją.
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Non-Perfect Propagation of Information to a Noisy Environment with Self-Evolution
PublicationWe study the non-perfect propagation of information for evolving a low-dimensional environment that includes self-evolution as well as noisy initial states and analyse the interrelations between the degree of objectivization and environment parameters. In particular, we consider an analytical model of three interacting qubits and derive its objectivity parameters. The numerical analysis shows that the quality of the spectrum broadcast...
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Simulating coherent light propagation in a random scattering materials using the perturbation expansion
PublicationMultiple scattering of a coherent light plays important role in the optical metrology. Probably the most important phenomenon caused by multiple scattering are the speckle patterns present in every optical imaging method based on coherent or partially coherent light illumination. In many cases the speckle patterns are considered as an undesired noise. However, they were found useful in various subsurface imaging methods such as...
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Numerical investigation of the core eccentricity effect on wave propagation in embedded waveguide
PublicationThe paper presents results of theoretical and numerical investigation of guided wave propagation in two-layer bars with geometric imperfections in the form of eccentric location of steel core. Steel rod of diameter equal to 1 cm embedded in composite mortar-type cover with external diameter equal to 5 cm has been taken into consideration. Several different rods with variable size of eccentricity are analysed. Results for rods with...
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Sea surface temperature distribution during upwelling along the Polish Baltic coast
PublicationAmong over 150 maps of sea surface temperature in the Polish Baltic coastal region derived from satellite data during the warm period of the year (April-October) in 2000-2002, 41 cases were noted where its distribution showed characteristic features indicating the occurrence of coastal upwelling. The fundamental parameters of range, probability of occurrence and temperature modification caused by water from deeper sea layers...
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Converting beach wrack into a resource as a challenge for the Baltic Sea (an overview)
PublicationThe paper distinguishes beach wrack, the marine generated organic part of beach cast, as a separate management object and discusses research questions related to its management and economically viable use. Based on experiences from the Baltic Sea and existing practices from countries with different management systems clear distinction between the management of natural and anthropogenic components of cast material is seen as an...
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Guided wave propagation in debonding detection in CFRP-reinforced steel plate-like structures
PublicationThe present study investigates the guided wave propagation in multilayered steel specimens reinforced with carbon fiber reinforced polymer (CFRP) through theoretical, numerical, and experimental means. The effectiveness of externally bonded reinforcement (EBR) relies heavily on the bonding quality between the CFRP and the substrate. Premature debonding, a prevalent and hazardous defect, can arise from suboptimal manufacturing processes,...
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Design and characterization of apatite La9.8Si5.7Mg0.3O26±δ-based micro-tubular solid oxide fuel cells
PublicationIn this study, electrolyte-supported (Cell A) and anode-supported (Cell B) micro-tubular solid oxide fuel cells (SOFCs) based on the La9.8Si5.7Mg0.3O26±δ (LSMO) electrolyte is built through an extrusion and dip-coating processes. The formulations and process conditions for these cells are established and optimized. Both cell configurations show no visible delamination or cracking, and reaction zones and inter-diffusion of any species...
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Effects of Ca2+, Mg2+, Na+, and K+ substitutions on the microstructure and electrical properties of GdCoO3 ceramics
PublicationGdCoO3-δ, Gd0.975Na0.025CoO3-δ, Gd0.98K0.02CoO3-δ, Gd0.98Ca0.02CoO3-δ, and GdCo0.99Mg0.01O3-δ ceramics were prepared via a solid-state reaction route. Among the dopants studied, substitution with Ca2+ slightly enhanced the densfication of GdCoO3 ceramics. All the lattice parameters of the doped ceramics were larger than those of pure GdCoO3-δ ceramic (a = 5.223 Å, b = 5.389 Å and c = 7.451 Å), and their cell volumes increased by...
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Processing of Ce0.8Gd0.2O2-δ barrier layers for solid oxide cells: The effect of preparation method and thickness on the interdiffusion and electrochemical performance
PublicationCe0.8Gd0.2O1.9 (CGO) barrier layers are required to mitigate the chemical reactions between Sr-containing oxygen electrode materials and Zr-based oxygen ion conductors in high-temperature solid oxide cells. Barrier layers produced by different methods were studied in this work. As a reference, a cell with no barrier layer was measured. The application of the powder-processed barrier layers, considerably increases the performance....
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Debonding Detection in Reinforced Concrete Beams with the Use of Guided Wave Propagation
PublicationOne of the most frequent damage of the reinforced concrete structures is debonding between steel bar and concrete cover. In the case of debonding occurrence not only the strength of the structure decreases, but also it is more vulnerable to corrosion damages. For this reason fast and effective methods of debonding detection in an early stage of its development need a significant boost. The paper presents analytical and experimental...
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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...
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FEM-based wave propagation modelling for SHM: Certain numerical issues in 1D structures
PublicationThe numerical modelling of structural elements is an important aspect of modern diagnostic systems. However, the process of numerical implementation requires advanced levels of consideration of multiple aspects. Important issues of that process are the positive and negative aspects of solution applied methods. Therefore the aim of this article is to familiarise the reader with the most important aspects related to the process of...
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Sea-dumped ammunition as a possible source of mercury to the Baltic Sea sediments
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Exposure status of sea-dumped chemical warfare agents in the Baltic Sea
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Deep sea habitats in the chemical warfare dumping areas of the Baltic Sea
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A high-accuracy method of computation of x-ray waves propagation through an optical system consisting of many lenses
PublicationThe propagation of X-ray waves through an optical system consisting of many X-ray refractive lenses is considered. Two differential equations are contemplated for solving the problem for electromagnetic wave propagation: first – an equation for the electric field, second – an equation derived for a complex phase of an electric field. Both equations are solved by the use of a finite-difference method. The simulation error is estimated...
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Operational algae bloom detection in the Baltic Sea using GIS and AVHRR data
PublicationDuring the blooming season, algal colonies can, in extreme cases, cover up to 200 000 square kilometres of the Baltic Sea water surface. Because the position and shape of the blooms may significantly change in very short time due to the influence of wind and waves, regular monitoring of the blooms' development is necessary. Currently, the desired monitoring frequency may only be achieved by means of remote sensing. The article...
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Processing data on sea bottom structure obtained by means of the parametric sounding
PublicationThe aim of the paper is to analyze data obtained during sounding the Gdansk Bay sea bed by means of the parametric echo-sounder. The accuracy of the sea bottom structure investigation needs correct configuration of research equipment and proper calibration of peripheral devices (GPS, heading sensor, MRU-Z motion sensor and navigation instruments which provide necessary data to bathymetrical measurement system, enabling its work...
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A GIS based approach for the mitigation of surface runoff to a shallow lowland reservoir
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Underwater communication system for shallow water using modified MFSK modulation
PublicationOpisano budowę i zasadę działania systemu komunikacji podwodnej z modulacją MMFSK. System służy do przekazywania danych i komend ze statku do obiektów podwodnych w płytkich wodach przybrzeżnych i jeziorach. Priorytetowe wymagania postawione systemowi to bardzo małe zużycie energii w części podwodnej i bardzo mała liczba błędów transmisji. Szczególną uwagę zwrócono na nietypowe źródło błędów, jakim są zniekształcenia nieliniowe...
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Instrumented end notched flexure - Crack propagation and process zonemonitoring Part II: Data reduction and experimental
PublicationA mode II instrumented end notched flexure three point bending (ENF) adhesion test is described. The adhesive joint consists of two aluminium alloy (AW7075-T6) plates bonded with a structural epoxy adhesive (Hysol EA 9395™). Strain gauges are attached to the outer surface (backface) of the substrates in the lengthwise direction to measure local surface strain during crack propagation. Simultaneously, load/displacement measurements...
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Sea spectra revisited
PublicationPokazano, że widma falowania ITTC, wywodzące się z widma Bretschneidera, zależnego od dwóch parametrów, można zredukować do wspólnego widma bezwymiarowego, co oznacza, że są one geometrycznie powinowate. To samo dotyczy widma JONSWAP, które dodatkowo charakteryzuje trzeci paprametr, związany z kształtem piku. Umożliwia to aproksymację tych widm za pomocą rozkładu log-normalnego, co zapewnia realistyczny parametr szerokości widma,...
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Estimation of groundwater recharge in a shallow sandy aquifer using unsaturated zone modeling and water table fluctuation method
PublicationQuantification of groundwater recharge is one of the most important issues in hydrogeology, especially in view of the ongoing changes in climate and land use. In this study, we use numerical models of 1D vertical flow in the vadose zone and the water table fluctuation (WTF) analysis to investigate local-scale recharge of a shallow sandy aquifer in the Brda outwash plain in northern Poland. We show that these two methods can be...
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EDUCATIONAL ENGAGEMENT OF THE ELDERLY – THE EXPERIENCES OF THE SELECTED BALTIC SEA REGION (BSR) COUNTRIES
PublicationThe aim of this article is to present the engagement of the elderly being close to retirement age in the Baltic Sea Region countries in the education of the adults, as well as to discuss the possibilities and conditions for the educational activity of the elderly. The authors also refer to the relationship between the participation of the elderly in education and their socio-economic situation.
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Oriented Gaussian beams for high-accuracy computation with accuracy control of X-ray propagation through a multi-lens system
PublicationA highly accurate method for calculating X-ray propagation is developed. Within this approach, the propagating wave is represented as a superposition of oriented Gaussian beams. The direction of wave propagation in each Gaussian beam agrees with the local direction of propagation of the X-ray wavefront. When calculating the propagation of X-ray waves through lenses, the thin lens approximation is applied. In this approximation,...
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BP-EVD: Forward Block-Output Propagation for Efficient Video Denoising
PublicationDenoising videos in real-time is critical in many applications, including robotics and medicine, where varying light conditions, miniaturized sensors, and optics can substantially compromise image quality. This work proposes the first video denoising method based on a deep neural network that achieves state-of-the-art performance on dynamic scenes while running in real-time on VGA video resolution with no frame latency. The backbone...
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Detection of ferromagnetic objects in local magnetic anomaly of the Baltic Sea
PublicationIn geological researches several kinds of methods are applied to discovering the natural resources. Planes, helicopters and UAVs (UnmAnned Vehicle) are used in researches in large areas. The gravity, electromagnetic and magnetic methods, which are used in geological researches, are presented in this paper. The special attention was paid to magnetic systems installed on mobile platforms. The magnetic field of the Earth obtained...
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Maritime Communication and Sea Safety of the Future - Machnine-type 5G Communication Concept
PublicationThe article presents the concept of a system based on 5G network and M2M communication increasing maritime safety. Generally, the focus was on presenting a proposal for a hierarchical, hybrid, cooperative system with M2M communication coordinated with BAN networks. The possi-ble applications of M2M communication at sea were also presented.
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High Frequency Conducted Emission in AC Motor Drives Fed By Frequency Converters: Sources and Propagation Paths
PublicationProvides a concise and thorough reference for designing electrical and electronic systems that employ adjustable speed drives Electrical and electronic systems that employ adjustable speed drives are being increasingly used in present-day automation applications. They are considered by many application engineers as one of the most interfering components, especially in a contemporarily faced industrial environment. This book fills...
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Analysis of the objects images on the sea using Dempster-Shafer Theory
PublicationThe paper presents the concept of using aerial and satellite imagery or images coming from the marine radar to identify and track vessels at sea. The acquired data were subjected to a highly advanced image analysis. The development of remote sensing techniques allows to gain a huge amount of data. These data are useful information source however usually we have to use different data mining methods to gain interested information....
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Chemical composition of shells from red (Strongylocentrotus franciscanum) and green (Strongylocentrotus droeba-chiensis) sea urchin
PublicationThe shells from red and green sea urchins accounted for 47.9 and 40.7% of their body weights, respectively. The red and green sea urchin shells contained 91.08 and 90.77% minerals and 4.06 and 4.99% proteins, respectively. The shells did not contain any chitin. Sea urchin shells had a relatively large amount of naphthoquinone pigments, 121 mg per 100 g in red and 163 mg per 100 g in green species. The small quantities of glucosamine...
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FINANCIAL COMPARISON OF WESTERN BALKAN AND BALTIC SEA STATES USING THE CAMEL APPROACH
Publication• The aim - This article aims to compare the situation in the banking sectors of two regions, which due to their political and economic history have much in common. These are the Western Balkan States of Serbia, Croatia and Macedonia, and the Baltic Sea States of Lithuania, Estonia, and Latvia. • Methods - It presents three approaches to defining banking stability that can be found in the literature and carries out an initial...
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Toward Safe and Efficient Recovery of Gas Munitions Dumped at Sea
PublicationThe proposal of a system for the safe recovery of unexploded ordnance (UXO), chemical weapons (CW) and chemicalwarfare agents (CWA) dumped at sea mainly after WWI and WWII is described in this work. The proposed solutionaddresses the tasks required to neutralise thousands of tons of dumped material and the currently available solutionsand proposed ideas. Requirements concerning the features of a recovery system are defined and...
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Simulating propagation of coherent light in random media using the Fredholm type integral equation
PublicationStudying propagation of light in random scattering materials is important for both basic and applied research. Such studies often require usage of numerical method for simulating behavior of light beams in random media. However, if such simulations require consideration of coherence properties of light, they may become a complex numerical problems. There are well established methods for simulating multiple scattering of light (e.g....
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Numerical Model of Surface and Quasi-Spherical Sea Noise and Its Application to Analysis of DIFAR Systems
PublicationVarious types of passive sonar systems are used to detect submarines. These activities are complex and demanding. Therefore, computer simulations are most often used at the design stage of these systems. For this reason, it is also necessary to simulate the acoustic ambient noise of the sea. The article proposes a new numerical model of surface and quasi-spherical sea noise and presents its statistical parameters. The results of...
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The effect of multiaxial geocomposite reinforcement on fatigue performance and crack propagation delay in double-layered asphalt beams
PublicationThe presented study investigates the effect of a recently developed multiaxial geocomposite made of polypropylene geogrid and non-woven fabric on the delay of crack propagation, based on four-point bending tests of large asphalt concrete beams – both for reinforced and non-reinforced specimens. Several approaches are described in this study, including analysis of stiffness modulus decrease and analysis of crack propagation using...
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System information propagation for composite structures
PublicationWe study in details decoherence process of a spin register, coupled to a spin environment. We use recently developed methods of information transfer study in open quantum systems to analyze information flow between the register and its environment. We show that there are regimes when not only the register decoheres effectively to a classical bit string, but this bit string is redundantly encoded in the environment, making it available...
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Modeling of light propagation in canine gingiva
PublicationThis study is a preliminary evaluation of the effectivenes of laser-based surgery of maxillary and mandibular bone in dogs. Current methods of gingivial surgery in dogs require the use of general anaesthesia.1, 2 The proposed methods of laser surgery can be performed on conscious dogs, which substantially reduces the associated risks. Two choices of lasers, Nd:YAG and a 930 nm semiconductor lasers were evaluated. The former is...
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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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Sea, River, Lake Ice Properties and Their Applications in Practices
PublicationThis Special Issue aims to highlight research articles focusing on the geographical scale of glacier and lake ice variations, as well as the engineering scale of ice properties and their practical applications via laboratory tests and numerical modeling. Additionally, it includes research on ecosystems under lake ice. The main goal is successfully achieved through the joint efforts of authors, anonymous reviewers, and editorial...
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Spatial and interannual variations of seasonal sea surface temperature patterns in the Baltic Sea
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REVERSE MODELLING OF MICROSEISMIC WAVES PROPAGATION FOR THE INTERPRETATION OF THE DATA FROM HYDRAULIC FRACTURING MONITORING IN POLAND
PublicationA hydraulic fracturing job was performed to stimulate gas flow from a horizontal wellbore located in Poland. The whole operation was overseen by means of microseismic monitoring. For this purpose, an array of 12000 geophones was deployed on ground in form of patches distributed unevenly in a region of 4km from the wellbore. The array was constantly recording seismic signals during whole fracturing processed. Such recorded signals...
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Propagation of initially sawtooth periodic and impulsive signals in a quasi-isentropic magnetic gas
PublicationThe characteristics of propagation of sawtooth periodic and impulsive signals at a transducer are analytically studied in this work. A plasma under consideration is motionless and uniform at equilibrium, and its perturbations are described by a system of ideal magnetohydrodynamic equations. Some generic heating/cooling function, which in turn depends on equilibrium thermodynamic parameters, may destroy adiabaticity of a flow and...