Temat: surface current - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Elastic electroconducting surface in magnetostatic field
Elektroprzewodząca powierzchnia sprężysta w polu magnetostatycznym
Autorzy:: Rudnicki, M.
Powiązania:: https://bibliotekanauki.pl/articles/279617.pdf
Data publikacji:: 2005
Wydawca:: Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:: magnetoelasticity
material surface
membrane theory
surface current
real electric conductor
perfect electric conductor
residual stress
Opis:: The dynamical linear theory of a material surface placed in vacuum and subjected to an external strong magnetostatic field is considered. Motion of the surface is described by a position function The material of the surface is assumed to be an isotropic elastic non-magnetizable electric conductor. The residual stress is taken into account. Displacement-based field equations are obtained in coordinate-free notation.
Przedmiotem rozważań jest teoria liniowa powierzchni materialnej umieszczonej w próżni i poddanej działaniu silnego zewnętrznego pola magnetostatycznego. Ruch powierzchni opisuje funkcja położenia. Założono, że materiał powierzchni jest izotropowy, sprężysty, niemagnetozywalny i przewodzący prąd elektryczny. Uwzględniono naprężenia rezydualne. Otrzymano równania rozwiązujące z użyciem przemieszczeń.
Źródło:: Journal of Theoretical and Applied Mechanics; 2005, 43, 1; 111-118
1429-2955
Pojawia się w:: Journal of Theoretical and Applied Mechanics
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Aggregating sea surface hydrodynamic forecasts from multi-models for European seas
Autorzy:: Frishfelds, V.
She, J.
Murawski, J.
Nielsen, J. W.
Powiązania:: https://bibliotekanauki.pl/articles/24201473.pdf
Data publikacji:: 2023
Wydawca:: Uniwersytet Morski w Gdyni. Wydział Nawigacyjny
Tematy:: weather research and forecasting
search and rescue
operational ocean forecasting
European Satellite Systems
surface current
drifting sea surface temperature
European waters
Opis:: Maritime information services supporting European agencies such as the FRONTEX require European‐wide forecast solutions. Following a consistent approach, regional and global forecasts of the sea surface conditions from Copernicus Marine Service and national met‐ocean services are aggregated in space and time to provide a European‐wide forecast service on a common grid for the assistance of Search and Rescue operations. The best regional oceanographic model solutions are selected in regional seas with seamless transition to the global products covering the Atlantic Ocean. The regional forecast models cover the Black Sea, Mediterranean Sea, Baltic Sea, North Sea and combine the North Sea – Baltic Sea at the Danish straits. Two global models have been added to cover the entire model domain, including the regional models. The aggregated product is required to have an update frequency of 4 times a day and a forecasting range of 7 days, which most of the regional models do not provide. Therefore, smooth transition in time, from the shorter timerange, regional forecast models to the global model with longer forecast range are applied. The set of parameter required for Search and Rescue operations include sea surface temperature and currents, waves and winds. The current version of the aggregation method was developed for surface temperature and surface currents but it will be extended to waves in latter stages. The method relies on the calculation of aggregation weights for individual models. For sea surface temperature (SST), near real‐time satellite data at clear‐sky locations for the past days is used to determine the aggregation weights of individual forecast models. A more complicated method is to use a weighted multi‐model ensemble (MME) approach based on best forecast features of individual models and possibly including near real time observations. The developed method explores how satellite observations can be used to assess spatially varying, near real time weights of different forecasts. The results showed that, although a MME based on multiple forecasts only may improve the forecast, if the forecasts are unbiased, it is essential to use observations in the MME approach so that proper weights from different models can be calculated and forecast bias can be corrected. It is also noted that, in some months, e.g., June in Baltic Sea, even SST was assimilated, the forecast still show quite high error. There are also visible difference between different Copernicus Marine Environment Monitoring Service (CMEMS) satellite products, e.g. OSTIA and regional SST products, which can lead different forecast quality if different SST observation products are assimilated.
Źródło:: TransNav : International Journal on Marine Navigation and Safety of Sea Transportation; 2023, 17, 3; 533--541
2083-6473
2083-6481
Pojawia się w:: TransNav : International Journal on Marine Navigation and Safety of Sea Transportation
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Waves, Currents and Seabed Level Change in the Port of Gdynia During Extreme Events
Autorzy:: Sapiega, P.
Zalewska, T.
Wochna, A.
Powiązania:: https://bibliotekanauki.pl/articles/24201476.pdf
Data publikacji:: 2023
Wydawca:: Uniwersytet Morski w Gdyni. Wydział Nawigacyjny
Tematy:: gulf of Gdansk
sea wave
hazard analysis
Harbour areas
transport from seabed
hydrodynamic effects
surface current
hydrodynamic model
Opis:: The primary purpose of the paper is to identify port areas most exposed to extreme hydrodynamic conditions (waves, sea currents, seabed level change). The results of modelling using SWAN wave model, MIKE 3D model, and reanalysis and measurement data were used in paper. Swell may exceed 0.8 m for winds exceeding 15 m s-1 from the west and south. During extreme conditions, sea currents can reach 0.4 ms-1 in the outer part of the bay adjacent to the port. Port basins do not show changes in the thickness of the seabed for the given maximum values of bottom currents. The most extensive deposition of the seabed and shore sediments (up to 0.04 m) is found on the Gdynia-Oksywie beach adjacent to the port and the approach fairway at the offshore currents. The outer area of the main breakwater is the most exposed to erosive activity (-0.012 m).
Źródło:: TransNav : International Journal on Marine Navigation and Safety of Sea Transportation; 2023, 17, 3; 515--521
2083-6473
2083-6481
Pojawia się w:: TransNav : International Journal on Marine Navigation and Safety of Sea Transportation
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Comparative analysis of the data on the surface currents and wind parameters generated by numerical models on the Szczecin Lagoon area
Autorzy:: Kijewska, M.
Pleskacz, K.
Kasyk, L.
Powiązania:: https://bibliotekanauki.pl/articles/117323.pdf
Data publikacji:: 2018
Wydawca:: Uniwersytet Morski w Gdyni. Wydział Nawigacyjny
Tematy:: Szczecin Lagoon
surface current
wind parameters
hydrodynamic model
weather forecast
numerical models
Geographic Information System (GIS)
High Frequency Surface Wave Radar (HFSWR)
Opis:: This study focuses on the investigation of available surface currents and wind parameters for employing them in order to predict the survivor movement in the Szczecin Lagoon waters. For this purpose, the surface currents and wind parameters were generated by selected numerical models and the wind parameters were also measured with the telemetry devices. In this paper, the PM3D hydrodynamic model and the NEMS, ECMWF, GFS weather forecast models have been investigated. The measurements of the wind parameters, recorded at the Brama Torowa I and Trzebież stations, were also analyzed. As part of the research, an expert method was used to evaluate the surface currents parameters. In turn, the method based on comparing the forecasted wind parameters with the measured wind parameters was applied in order to assess uncertainties of these parameters. The comparative analyses of the data on the surface currents and wind parameters have been done and probabilistic models for uncertainties of these forecasted parameters have been formulated. Additionally, relations between the surface currents speeds and the wind speeds, in the case when their directions were consistent, have been also discovered.
Źródło:: TransNav : International Journal on Marine Navigation and Safety of Sea Transportation; 2018, 12, 4; 729-737
2083-6473
2083-6481
Pojawia się w:: TransNav : International Journal on Marine Navigation and Safety of Sea Transportation
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Zastosowanie teorii perkolacji do wyznaczania mocy wydzielanej na próbkach kompozytowych
Application of percolation theory for determination of power emitted on composite samples
Autorzy:: Frączak, P. S.
Czajkowski, A. A.
Powiązania:: https://bibliotekanauki.pl/articles/135872.pdf
Data publikacji:: 2015
Wydawca:: Wyższa Szkoła Techniczno-Ekonomiczna w Szczecinie
Tematy:: prąd upływnościowy powierzchniowy
próbki kompozytowe
teoria perkolacji
moc pozorna
symulacja
MathCAD
surface leakage current
composite samples
percolation theory
apparent power
simulation
Opis:: Wstęp i cele: W pracy przedstawiono sposób analityczno-numeryczny wyznaczania wartości mocy wydzielanej na próbkach walcowych kompozytowych przez prąd upływnościowy powierzchniowy w ujęciu teorii perkolacji. W przyjętym modelu sformułowano w zapisie macierzowym prąd perkolacji, impedancję i moc wydzielaną na powierzchni próbek kompozytowych. Celem pracy było wyznaczenie wartości mocy traconej na powierzchni próbek kompozytowych. Materiał i metody: Podstawą opracowania była literatura dotycząca perkolacji. Badania starzeniowe oparto metodzie MGR (ang. Merry-Go-Round) dla próbek kompozytowych. Zastosowano metodę tak analityczno-numeryczną jak i doświadczalną. Wyniki opracowano numerycznie w programie MathCAD. Wyniki: W wyniku obliczeń analityczno-numerycznych uzyskano wartości mocy pozornej wydzielanej na powierzchni badanych próbek kompozytowych. Opracowano graficznie charakterystyki mocy pozornej. Wniosek: Podczas badania starzeniowego próbki kompozytowej metodą MGR, po osiągnięciu progu perkolacji następuje wzrost mocy pozornej wydzielanej na jej powierzchni.
Introduction: Analytical and numerical determination of power occurring on cylinder composite samples by surface leakage current in the aspect of percolation theory have been presented in the paper. In the given model the value of percolation current, impedance and power occurring on the samples have been defined in matrix notation. Some determinations of power in the aspect of percolation theory have been elaborated in the paper. The main aim of the paper is some determination of apparent power values on the surface of composite samples. Material and methods: The basis of the study was literature contained percolation theory. The study was based on aging method MGR (Merry-Go-Round) for composite samples. In the paper have been used not only the analytical and numerical but also some experimental method. The results have been numerically elaborated in the MathCAD program. Results: Using some analytical and numerical calculations have been obtained the values of apparent power emitted on the surface of the tested composite samples. The apparent power characteristics have been graphically elaborated in the study. Conclusion: During the senescence study of the composite sample by MGR method, after reaching the percolation threshold there is an increase apparent power emitted on its surface.
Źródło:: Problemy Nauk Stosowanych; 2015, 3; 107-116
2300-6110
Pojawia się w:: Problemy Nauk Stosowanych
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Seasonal Variations of Sea Surface Temperature and Sea Current in the Celebes Sea
Autorzy:: Hapsari, Siti Nirmala
Syamsuddin, Mega Laksmini
Riyantini, Indah
Sunarto, Sunarto
Powiązania:: https://bibliotekanauki.pl/articles/1031483.pdf
Data publikacji:: 2021
Wydawca:: Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:: Celebes Sea
Sea Current
Sea Surface Temperature
Opis:: The waters of the Celebes Sea are an area that has quite complex dynamics because it is influenced by several factors, either regionally or globally. This influence certainly has an impact on variations in oceanographic conditions in waters such as Sea Surface Temperature (SST) and sea currents. Currently, there are many observations of oceanographic data, one of which is by using remote sensing methods. The purpose of this study was to determine the seasonal variations in sea surface temperature and sea surface currents in the Celebes Sea using a remote sensing system in a time series for 5 years (2014-2018). The results of this study indicate data on seasonal variation of SST and sea surface currents have an average maximum SST value for 5 years occurring in the eastern season and the second transitional season (May, June, July) with an average value range of 30.6 °C - 31.1 °C and the average maximum sea current velocity for 5 years occurs in the western monsoon with a value range of 0.72 m/s - 0.77 m/s. The high SST value and sea current velocity are caused by the influence of the season which causes variations in the ongoing rainfall, also presumably due to the opposite direction between the monsoon wind and the direction of the main current flowing in the Celebes Sea.
Źródło:: World News of Natural Sciences; 2021, 35; 135-143
2543-5426
Pojawia się w:: World News of Natural Sciences
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: A simple and precise method for the threshold current determination in vertical-cavity surface-emitting lasers
Autorzy:: Pruszyńska-Karbownik, Emilia
Gębski, Marcin
Marciniak, Magdalena
Lott, James A.
Czyszanowski, Tomasz
Powiązania:: https://bibliotekanauki.pl/articles/174774.pdf
Data publikacji:: 2020
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:: VCSEL
vertical-cavity surface-emitting laser
threshold current
spontaneous emission
Opis:: In this paper, we present experimental results of spontaneous emission clamping in the threshold for vertical-cavity surface-emitting lasers (VCSELs) with oxide current confinement. We show that the spontaneous emission not wholly clamps in the threshold. We propose a new method for determining the threshold current value using the study of the clamping phenomena. This method has an advantage over the commonly used methods in the accuracy because the current of the spontaneous emission clamping is betted defined than the current of the slope change of the stimulated emission light-current curve. The estimated uncertainty of the method is no more than 20 μA.
Źródło:: Optica Applicata; 2020, 50, 2; 281-288
0078-5466
1899-7015
Pojawia się w:: Optica Applicata
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Dynamics of the FKT system with different mooring lines
Autorzy:: Wu, Jo-Ti
Chen, Jiahn-Horng
Hsin, Ching-Yeh
Chiu, Forng-Chen
Powiązania:: https://bibliotekanauki.pl/articles/258986.pdf
Data publikacji:: 2019
Wydawca:: Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:: ocean current energy
floating turbine system
mooring line
system dynamics
surface waves
Opis:: To harness the endless hydrokinetic energy of the Kuroshio current, the joint research team of the National Taiwan University and the National Taiwan Ocean University has developed a floating Kuroshio turbine (FKT) system in Taiwan. In normal operation, the system floats at a certain small depth from the ocean surface to reduce the wave effects and take advantage of faster current speeds. In the present study, the effect of the mooring line on the system dynamics is investigated computationally. Two different auxiliary mooring line designs and, for each design, three different common mooring lines (polyester ropes of neutral buoyancy, iron chains, and 6×19 wires ropes with wire core) are examined. The study makes use of several commercial and in-house packages, integrated to find various coefficients. It is found that the mooring line, the auxiliary mooring line design, and the gravity centre can have a significant effect on system fluctuations in normal operation if the combination of these factors is not properly matched.
Źródło:: Polish Maritime Research; 2019, 1; 20-29
1233-2585
Pojawia się w:: Polish Maritime Research
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Zmiany temperatury powierzchni Morza Barentsa w latach 1951-2006
Changes in the sea surface temperature of the Barents Sea in the years 1951-2006
Autorzy:: Zblewski, S.
Powiązania:: https://bibliotekanauki.pl/articles/260773.pdf
Data publikacji:: 2007
Wydawca:: Stowarzyszenie Klimatologów Polskich
Tematy:: temperatura powierzchni morza
NAO
Morze Barentsa
Prąd Zachodniospitsbergeński
Prąd Nordkapski
sea surface temperature
Barents Sea
West Spitsbergen Current
North Cape Current
Opis:: Praca charakteryzuje zmiany temperatury powierzchni Morza Barentsa (TPM) zachodzące w okresie 1951–2006. Stwierdzono występowanie słabych, dodatnich i istotnych statystycznie trendów TPM w gridach leżących poza obszarem bezpośredniego oddziaływania ciepłych prądów morskich. Odnotowano słaby i nierównomiernie rozłożony w przestrzeni wzrost temperatury powierzchni morza – silniejszy we wschodniej części Morza Barentsa. W badanym okresie (1951–2006) na obserwowaną zmienność rocznej TPM znacznie silniejszy wpływ wywierają procesy oceaniczne niż zmienność zimowej cyrkulacji atmosferycznej.
The aim of this work was to analyse monthly and annual values of sea surface temperatures of the Barents Sea in the years covering the period from 1951 up to 2006 averaged to chosen grids 2x2° (Fig. 1).The analysis showed that in the course of SST a clearly marked period (1976–1988) of significant decrease in annual values of water temperature was noted, with the minimum observed in 1980 (Fig. 2). This phenomenon is connected with Great Salinity Anomaly.The research showed that the general decrease in annual SST takes place towards north-east and at the same time, following the same direction, the increase in amplitude of inter-annual changes can be observed (Fig. 3). ‘The warm sources of the North Cape Current and West Spitsbergen Current moving away and the transfer of heat from the ocean to the atmosphere are the cause of this situation. This significant drop in annual sea surface temperature in the NE part of the Barents Sea is also influenced by flows of cold and fresh Surface Arctic Waters from the Arctic and Kara seas. There were also great differences observed in the course of annual SST in the western and eastern parts of the examined sea area. (Fig.4). In the eastern part rapid falls in water temperature can be noted by even 0.7°C from year to year. They result from the sea ice spreading and Surface Arctic Waters from the Kara Sea and from the north region of the Barents Sea which cut off the flow of heat from the deeper parts of the sea towards the surface and to the atmosphere.In the examined period weak positive trends in the annual sea surface temperature were observed and they are statistically significant in almost all grids (Tab.1). The strongest trends were noted in the east part of the examined sea area. Positive and statistically significant trends of the monthly SST are observed in summer and autumn in grids located farthest NE.The analysis showed that the influence of winter atmospheric circulation on the temperature of the sea surface is weak or rather moderate (Tab. 2) and that the observed changeability in annual sea surface temperature of the Barents Sea is mainly controlled by oceanic processes.
Źródło:: Problemy Klimatologii Polarnej; 2007, 17; 61-70
1234-0715
Pojawia się w:: Problemy Klimatologii Polarnej
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Heat and salt fluxes in the West Spitsbergen Current area in summer
Autorzy:: Piechura, J.
Osinski, R.
Petelski, T.
Wozniak, S.B.
Powiązania:: https://bibliotekanauki.pl/articles/49050.pdf
Data publikacji:: 2002
Wydawca:: Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:: Spitsbergen Current
temperature
radiation flux
energy flux
heat flux
sea surface
salt flux
ocean circulation
Opis:: Fluxes of radiation, sensible and latent heat, and fluxes of heat and salt within the upper layer of the ocean were calculated on the basis of measurements carried out in the area of the Norwegian-Atlantic and West Spitsbergen Currents during summer 2000. The sea surface radiation balance was calculated from direct measurements of downward and upward short-wave (solar) radiation, the net radiation fluxes and sea surface temperature. The daily doses of radiation energy reaching and leaving the sea surface were also estimated. To calculate the vertical heat fluxes in the atmospheric boundary layer the bulk parameterisation method was used. In most cases, the calculated heat fluxes were rather low, the average sensible heat flux was c. 10 Wm−2, and the latent heat flux about one order of magnitude higher; this is what could be expected in summer. Salt fluxes to the air in the process of aerosol production are very small and can be neglected. In summer the highest quantities of heat and salt are exchanged during mixing with surrounding waters. According to our measurements, Atlantic Water on its northward course from about 70◦N to 79◦ N loses about 100 TWof heat and 900 × 103 kg of salt. We thought it could be interesting to find out what happens to them. Some preliminary results of our investigation are presented here.
Źródło:: Oceanologia; 2002, 44, 3
0078-3234
Pojawia się w:: Oceanologia
Dostawca treści:: Biblioteka Nauki

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