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Wyszukujesz frazę "depth factor" wg kryterium: Temat


Wyświetlanie 1-6 z 6
Tytuł:
Augmentation in heat transfer and friction of three sides over one side dimple roughened solar duct
Autorzy:
Kumar, Vikash
Powiązania:
https://bibliotekanauki.pl/articles/240256.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
dimple roughened
relative roughness pitch
relative roughness height
dimple depth to diameter ratio
nusselt number
friction factor
Opis:
Providing roughness is an effective method to heat fluids to high temperature. Present paper make use of concave dimple roughness on one and three sides of roughened ducts aimed at determining rise in heat transfer and friction of three sides over one side roughened duct. Three sides roughened duct produces high heat transfer compared to one side roughened. Results are shown as a rise in Nusselt number and friction factor of three sides over one side roughened duct. Experimental investigation was conducted under actual outdoor condition at National Institute of Technology Jamshedpur, India to test various sets of roughened collectors. Roughness parameter varied as relative roughness pitch 8–15, relative roughness height 0.018–0.045, dimple depth to diameter ratio 1–2, Reynolds number 2500– 13500 at fixed aspect ratio (width/hight) 8. Highest enhancement in Nusselt number for varying relative roughness pitch, height, and diameter ratio was respectively found as 2.6 to 3.55 times, 1.91 to 3.42 times and 3.09 to 3.94 times compared to one side dimple roughened duct. Highest rise in friction for three sides over one side roughened duct for these varying parameters was respectively found as 1.62 to 2.79 times, 1.52 to 2.34 times and 2.21 to 2.56 times. To visualize the effect of roughness parameter on heat transfer and friction factor, variation in Nusselt number and friction factor for varying roughness parameters with Reynolds number is shown.
Źródło:
Archives of Thermodynamics; 2020, 41, 3; 57-89
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Determining the best possible speed of the ship in shallow waters estimated based on the adopted model for calculation of the ship’s domain depth
Autorzy:
Rutkowski, Grzegorz
Powiązania:
https://bibliotekanauki.pl/articles/1573899.pdf
Data publikacji:
2020
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
safe speed
best possible speed
optimal speed
ship’s domain
safety depth
under keel clearance (UKC)
navigational risk factor
ship squat
Opis:
The purpose and scope of this article is to present the best marine practices used to determine the ship’s domain depth (compared to the safety depth parameter in ECDIS) and the safest and best possible speed (also known as optimal speed) of the ship in restricted sea areas limited by the depth of navigation waters. The author also presents a method that can be used to estimate the safe speed of a ship in shallow waters and the so-called navigational risk factor (specified in the range from 0 to 1), using the safety depth parameter specified in ECDIS based on the analysis of a three-dimensional model of the ship’s domain. The essence of the method proposed in this paper is a systematic approach to the operation of a seagoing ship in the aspect of assessing its navigation safety (navigational risk factor) when manoeuvring in restricted sea areas, in particular in shallow waters including navigable canals and fairways.
Źródło:
Polish Maritime Research; 2020, 3; 140-148
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A method for reliability assessment of structural components of aircraft and sea-going ships with taking into account a given failure generation model
Autorzy:
Tomaszek, H.
Zieja, M.
Ważny, M.
Powiązania:
https://bibliotekanauki.pl/articles/258768.pdf
Data publikacji:
2016
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
bearing capacity factor
displacement
compression
tension
depth factor
Opis:
This paper presents a metod for reliability assessment of structural components on the basis of diagnostic parameters recorded during operation of aircraft and sea going ships. It was assumed that a potential failure may simultaneously concerns surface wear process and fracture of an arbitrary structural component. In order to develop a reliability assessment model some elements of random walk theory were applied. This work covers surface wear density functions of a component. In the case of surface wear the model is based on a difference equation from which , after transformation, a Fokker-Planck partial differential equation was obtained. By solving the equation component’s surface wear density function is achieved. In the second part of the work a generalization of the model was made by introducing to it probability of disastrous fracture of a component. As a result, a generalized Fokkera-Planck’s equation was obtained. By making use of the equation, was obtained a relationship for assessment of reliability of a structural component in case when failure occurs due to surface wear with taking into account possible fracture of the component. In the end a numerical example which shows practical application of the developed method,is attached.
Źródło:
Polish Maritime Research; 2016, 2; 83-90
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical investigation of the undrained compression and pull-out capacity of suction foundations in clay
Autorzy:
Du, J.
Du, S.
Shena, S.
Yina, Z.
Powiązania:
https://bibliotekanauki.pl/articles/260167.pdf
Data publikacji:
2015
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
bearing capacity factor
displacement
compression
tension
depth factor
Opis:
This paper presents the results of three-dimensional finite difference analysis of suction foundations in uniform and non-uniform clays under undrained conditions. The Tresca criterion was used to simulate the stress-strain response. The bearing capacity of the foundations was investigated, with the degree of nonhomogeneity (kD/sum) of soil varying from 0 to 5, and the embedment depth being up to four times the foundation diameter. The end bearing capacity factor in compression and the reverse bearing capacity factor in tension were both calculated and were compared with each other under different foundation displacements. Numerical results showed that the ultimate bearing capacity factor can have the same value in cases of both compression and tension. The recommended ultimate bearing capacity factor is determined on the basis of the embedment ratio and displacement magnitude, and the displacement is not more than 30% of the foundation diameter. Finally, two equations are proposed to evaluate both the bearing capacity factor and the effective depth factor.
Źródło:
Polish Maritime Research; 2015, S 1; 126-135
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Practical applicability and preliminary results of the Baltic environmental satellite remote sensing system (SATBAŁTYK)
Autorzy:
Ostrowska, M.
Darecki, M.
Krężel, A.
Ficek, D.
Furmańczyk, K.
Powiązania:
https://bibliotekanauki.pl/articles/259162.pdf
Data publikacji:
2015
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
bearing capacity factor
displacement
compression
tension
depth factor
Opis:
The SatBałtyk (Satellite Monitoring of the Baltic Sea Environment) project is being realized in Poland by the SatBałtyk Scientific Consortium, specifically appointed for this purpose, which associates four scientific institutions: the Institute of Oceanology PAN in Sopot – coordinator of the project, the University of Gdańsk (Institute of Oceanography), the Pomeranian Academy in Słupsk (Institute of Physics) and the University of Szczecin (Institute of Marine Sciences). The project is aiming to prepare a technical infrastructure and set in motion operational procedures for the satellite monitoring of the Baltic Sea ecosystem. The main sources of input data for this system will be the results of systematic observations by metrological and environmental satellites such as TIROS N/NOAA, MSG (currently Meteosat 10), EOS/AQUA and Sentinel -1, 2, 3 (in the future). The system will deliver on a routine basis the variety of structural and functional properties of this sea, based on data provided by relevant satellites and supported by hydro-biological models. Among them: the solar radiation influx to the sea’s waters in various spectral intervals, energy balances of the short- and long-wave radiation at the Baltic Sea surface and in the upper layers of the atmosphere over the Baltic, sea surface temperature distribution, dynamic states of the water surface, concentrations of chlorophyll a and other phytoplankton pigments in the Baltic waters, spatial distributions of algal blooms, the occurrence of coastal upwelling events, and the characteristics of primary production of organic matter and photosynthetically released oxygen in the water and many others. The structure of the system and preliminary results will be presented.
Źródło:
Polish Maritime Research; 2015, 3; 43-49
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Variability of the portion of functional PS2 reaction centres in the light of a fluorometric study
Autorzy:
Ficek, D.
Ostrowska, M.
Kuzio, M.
Pogosyan, S.I.
Powiązania:
https://bibliotekanauki.pl/articles/48365.pdf
Data publikacji:
2000
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
marine phytoplankton
variability
quantum yield
chlorophyll a
optical depth
PS2 reaction
environmental factor
photosynthetic apparatus
sea
fluorometric method
light
photosynthesis
Opis:
The paper contains a preliminary analysis of the links between the portion fc of functional PS2 reaction centres in the photosynthetic apparatus of marine phytoplankton and environmental factors. The analysis is based inter alia on fluorometric measurements of fc (see Kolber & Falkowski 1993) in water sampled from different depths and trophic types of sea. From the statistical generalisations was derived an analytical form of the relationship between fc, and the optical depth and trophic type of sea (the trophicity index was taken to be the surface concentration of chlorophyll a). According to this relationship, fc rises as the trophicity of the sea does so. Moreover, there is a certain optimal optical depth for each type of water at which the number of functional PS2 reaction centres reaches a maximum. Above or below this depth the value of fc falls. At the present stage of investigations it seems reasonable to assume that this drop in the number of functional PS2 reaction centres close to the surface is due to the destructive effect of excessive irradiance. On the other hand, their reduced number at greater depths, below the fc maximum, can be attributed to the deficit of light and the consequent destruction of reaction centres.
Źródło:
Oceanologia; 2000, 42, 2
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-6 z 6

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