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wszystkich: 65
Wyniki wyszukiwania dla: PARAMETRIC SOUNDING OF SEA BOTTOM
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Pomiar odpowiedzi impulsowej kanału radiowego na obszarze morskim i przybrzeżnym
PublikacjaW artykule zaprezentowano wyniki pomiarów odpowiedzi impulsowej kanału radiowego na obszarze morskim i przybrzeżnym. Pomiary przeprowadzono na częstotliwości 1457 MHz a sygnałem sondującym był sygnał o paśmie 10 MHz z modulacją BPSK i pseudoprzypadkową zawartością binarną. Odbierane sygnały były rejestrowane przez dwie stacje ruchome, zainstalowane w samolocie i na łodzi patrolowej. Podczas późniejszej obróbki danych zastosowano...
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The hydrodynamic pressure field of the ship Zodiak, measurements and calculations
PublikacjaThe article presents the results of measurements of the slowly changing hydrodynamic pressure field HPF generated by the movement of the ship, Zodiak, in the Bay of Gdansk. The measurement results have been obtained in the framework of the program of the work in Siramis, under the auspices of the European Defence Administration of the EU, by the research team of the Naval Academy in Gdynia. The measurement results were compared with...
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A geophysical, geochemical and microbiological study of a newly discovered pockmark with active gas seepage and submarine groundwater discharge (MET1-BH, central Gulf of Gdańsk, southern Baltic Sea)
PublikacjaHigh-resolution bathymetric data were collected with a multi-beam echosounder in the southern part of the Baltic Sea (region MET1, Gulf of Gdańsk) revealing the presence of a 10 m deep and 50 m in diameter pockmark (MET1-BH) on the sea bottom (78.7 m). To date, no such structures have been observed to reach this size in the Baltic Sea. The salinity of the near-bottom water in the pockmark was about 2 PSU (about 31.22 mmol/l...
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Verification of algorithms determining wave loads on support structure of wind turbine
PublikacjaThe offshore wind turbines require determination of wave loads on their support structure. This structure is fixed and, therefore, this problem is reduced to solving only the diffraction problem, which is determined by Laplace equation and conditions on the following boundaries: on the support structure, on the sea free surface and on its bottom, and at infinity on free surface. The linear problem was applied to determine the wave...
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Numerical Analysis of Impact of Energy Buoy Anchoring Configurations on its Motion and Efficiency
PublikacjaThis paper presents a numerical analysis of the impact of energy buoy mooring configurations on its movement on the wave and effectiveness. The method used to analyse the buoy movement modelling in six degrees of freedom was described in a paper presented at the Conference 2011. Simulations of the buoy movement in regular wave and power calculations were conducted for several configurations of anchoring systems and position of...
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Investigation of the vertical distribution of the sound speed of the Gulf of Gdansk in the years 2000-2010
PublikacjaThe conditions of the acoustic wave propagation in the southern Baltic are much more complex than in other shallow waters. In the typical shallow water, seasonal changes in acoustical conditions in the upper layer, of the depth of about 60-70 m, are observed. They are caused by variation of the annual meteorological conditions. Most often, in the deep water layer, acoustical conditions are stable throughout the year. However, in...
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On Algorithm Details in Multibeam Seafloor Classification
PublikacjaRemote sensing of the seafloor constitutes an important topic in exploration, management, protection and other investigations of the marine environment. In the paper, a combined approach to seafloor characterisation is presented. It relies on calculation of several descriptors related to seabed type using three different types of multibeam sonar data obtained during seafloor sensing, viz.: 1) the grey-level sonar images (echograms)...
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The study of acoustic climate of the Southern Baltic
PublikacjaThis paper presents the statistical characteristics of seawater properties, which are necessary for predicting the propagation of acoustic waves in selected areas of the Baltic Sea. The statistics were elaborated based on long-term measurements of vertical distributions of sound speed, temperature, and salinity, and the nonlinearity parameter B/A. Nonlinear properties of the environment are considered, in connection...
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Stability analysis of a dike constructed of anthropogenic materials
PublikacjaNumerical analyses of stability are presented for a hypothetical dikes constructed of dredged materials and bottom ash, in varying proportions. The paper is related to the international research project DredgDikes, which focused on the use of anthropogenic materials in dikes construction and flood protection. The aim of this project was to investigate the possibility of using anthropogenic materials from rivers and sea dredging...
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Change in Heavy Metals Concentrations in Sediments Deposited in Retention Tanks in a Stream after a Flood
PublikacjaOur paper presents the results of heavy metal (HM) (Zn, Cu, Pb, Cd) content in bottom sediments from retention tanks along Oliwa Stream in Gdańsk, Poland, before a flood (BF) and after a flood (AF) 14-15 July 2016. The flood had a huge impact on the quality of bottom sediments and their displacement. The concentrations of HM differed significantly for research series conducted 3 months BF and 8 months AF. The concentration of Cu...
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Distribution and bioavailability of mercury in the surface sediments of the Baltic Sea
PublikacjaThe study aimed to determine the level of mercury (Hg) and its labile and stable forms in the surface sediments of the Baltic Sea. The work considers the impact of current and historical sources of Hg on sediment pollution, together with the influence of different environmental parameters, including water inflows from the North Sea. Surface sediments (top 5 cm) were collected in 2016–2017 at 91 stations located in different...
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Coastal cliff erosion as a source of toxic, essential and nonessential metals in the marine environment
PublikacjaDue to the rising environmental awareness, emissions and releases of pollutants, including metals, have been considerably reduced in the last decades. Therefore, the remobiliza-tion of natural and anthropogenic contaminants is gaining importance in their biogeochemical cycle. In the marine coastal zone, this process occurs during the erosion of a shore, especially the most vulnerable cliffs. The research was conducted in the...
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Seagrass vegetation and meiofauna enhance the bacterial abundance in the Baltic Sea sediments (Puck Bay)
PublikacjaThis study presents the first report on bacterial communities in the sediments of eelgrass (Zostera marina) meadows in the shallow southern Baltic Sea (Puck Bay). Total bacterial cell numbers (TBNs) and bacteria biomass (BBM) assessed with the use of epifluorescence microscope and Norland’s formula were compared between bare and vegetated sediments at two localities and in two sampling summer months. Significantly higher TBNs and...
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Usage of parametric echosounder with emphasis on buried object searching.
PublikacjaThe purpose of this article is to present the results of investigation to search for buried objects. The paper will contain echograms and other means of visualization from buried pipe placed between area of W?adys?awowo and gas platform and interesting in terms of the number of small and medium-sized unidentified objects found in the muddy bottom at different depths localized in the Gulf of Puck - results will be presented also...
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Bringing Bathymetry LiDAR to Coastal Zone Assessment: A Case Study in the Southern Baltic
PublikacjaOne of the major tasks in environmental protection is monitoring the coast for negative impacts due to climate change and anthropopressure. Remote sensing techniques are often used in studies of impact assessment. Topographic and bathymetric procedures are treated as separate measurement methods, while methods that combine coastal zone analysis with underwater impacts are rarely used in geotechnical analyses. This study presents...
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MAPPING SOUTH BALTIC NEAR-SHORE BATHYMETRY USING SENTINEL-2 OBSERVATIONS
PublikacjaOne of the most promising new applications of remote observation satellite systems (RO) is the near-shore bathymetry estimation based on spaceborn multispectral imageries. In recent years, many experiments aiming to estimate bathymetry in optically shallow water with the use of remote optical observations have been presented. In this paper, optimal models of satellite derived bathymetry (SDB) for relatively turbid waters of the...
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Whirling system of water exchangein breeding pools
PublikacjaTo secure the proper conditions of life for sea mammals existing in closed systems one has to maintain the character of the breeding basins (i.e. shape, dimensions, facing of walls and bottom, quality and motion of water) as natural as possible. An appropriate system of water exchange plays a very important role here. A full renewal of water is time-consuming, expensive and troublesome, so can be made only periodically, and should...
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The Application of a Mobile Unmanned Device for Monitoring Water and Sediment Pollution in the Port of Gdynia
PublikacjaPollution in the Port of Gdynia can encompass various types of substances and contaminants that affect the quality of water and sediment in this region. Ships entering and leaving the port can release pollutants such as oil, fuel, waste, and chemicals into the water. Controlling and monitoring these pollutants is a crucial part of environmental stewardship. In recent years, uncrewed units have been increasingly in use for in situ...
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Comparative analysis of the flow control over a circular cylinder with detached flexible and rigid splitter plates
PublikacjaA comparative study is performed on a circular cylinder with both flexible and rigid splitter plates (SPs). This study has the novelty of using single and dual detached SPs located downstream of the cylinder. The dimensionless gap distance between the first splitter plate and the cylinder as well as the distance between the SPs are varied. The strain of flexible SPs can be used for energy harvesting from the flow. Therefore, a...
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Trophic Transfer of Mercury in a Temperate Marine Food Web, Southern Baltic Sea
PublikacjaMercury (Hg) is considered to be one of the most dangerous global environmental pollutants. The toxicity and bioavailabilityof Hg depend on its chemical form, and the greatest hazard is posed by the organomercurial compounds. Hg is introduced into the human body primarily through the consumption of fish and seafood. Despite numerous studies on Hg in marine organisms, there is still a gap in the knowledge on Hg uptake and...