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Wyświetlanie 1-8 z 8
Tytuł:
Experimental investigation of local scour under two oblong piers of a bridge crossing a sharp bend river
Autorzy:
Abdulwahd, Abdulrazaq K.
Maatooq, Jaafar S.
Powiązania:
https://bibliotekanauki.pl/articles/28411623.pdf
Data publikacji:
2023
Wydawca:
Instytut Technologiczno-Przyrodniczy
Tematy:
flow intensity
local scour
oblong pier
sharp bend
Opis:
Bridges built across a river bend and supported by more than one pier has been experimentally studied regarding the shape and nature of erosion and deposition. For this purpose, a U-shaped laboratory channel was used with two oblong piers installed at different locations. The first one was at the mid-section of the upstream straight reach, whereas in the second site within the bend, the piers have been installed at sections of central angles 0°, 30°, 60°, 90°, 120°, 150°, 170°, and 180°, from the beginning to the end of the bend segment respectively. The studies were conducted under clear water and threshold flow conditions. The results show that the higher and lower values of local scour around the pier positioned close to the outer bank, are 1.803 and 0.623 times the pier width when the bridge was installed at an angle of 90° and 30° respectively. As for the pier close to the inner bank, the deepest local scour was 1.786 times of the pier width when the bridge was installed at 60° of the bend, while the least one was 0.516 times of the pier width when the bridge was located in the 180° sector. It is worth noting that the presence of piers within sector 150 is less affected by local scour than in the other sections.
Źródło:
Journal of Water and Land Development; 2023, 58; 129--135
1429-7426
2083-4535
Pojawia się w:
Journal of Water and Land Development
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Biostratigraphic re-evaluation of the lower to middle Miocene succession in the Eastern Carpathians : a case study related to the oil fields of the Diapir Fold Zone, Romania
Autorzy:
Filipescu, Sorin
Tămaş, Dan M.
Bercea, Răzvan-Ionuţ
Tămaş, Alexandra
Bălc, Ramona
Ţabără, Daniel
Bindiu-Haitonic, Raluca
Silye, Lóránd
Auer, Andreea
Krézsek, Csaba
Schléder, Zsolt
Săsăran, Emanoil
Powiązania:
https://bibliotekanauki.pl/articles/2060242.pdf
Data publikacji:
2020
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
biostratigraphy
re-evaluation
Carpathian Bend Zone
Miocene
microfossils
Opis:
Romania has a long history of hydrocarbon production and tens of thousands of boreholes have penetrated Miocene strata. Many well cores or cuttings have been either lost or damaged, but lab reports containing valuable petrographic, paleontological and structural data are still available. Most of the knowledge of the subsurface relies on old descriptions and interpretations used by the oil industry. These data have not been recently updated, while research results from the last decade suggest potential changes in stratigraphy, especially for the lower to middle Miocene succession. In order to update, calibrate, and reduce uncertainties regarding the subsurface stratigraphic record, we have reviewed the lab reports and used equivalent field samples for an updated interpretation of the lower to middle Miocene succession. Core and cutting descriptions from boreholes covering an area of ~10,000 km2 in the Diapir Fold Zone of the Eastern Carpathians have been selected and biostratigraphically re-evaluated based on microfossils and calcareous nannofossils. In many cases, highly uncertain ages were previously interpreted as Oligocene and early Miocene. Our recent data suggest that most of the lower Miocene is either difficult to determine or has been reinterpreted as middle Miocene (e.g., Cornu and Doftana formations). This significant change in ages requires an updated model for the timing of regional structural evolution and may open new exploration opportunities in this highly mature hydrocarbon area. This study demonstrates the need for a new complete and reliable stratigraphic framework for the whole Miocene stratigraphic record of the Eastern Carpathians.
Źródło:
Geological Quarterly; 2020, 64, 3; 781--800
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Minimum Bend Shortest Rectilinear Route Discovery for a Moving Sink in a Grid Based Wireless Sensor Network
Autorzy:
Thomas, Sanu
Mathew, Thomaskutty
Powiązania:
https://bibliotekanauki.pl/articles/226096.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
minimum bend shortest paths
travelling salesman problem
binary integer programming
edge orientation index
Vertex Bend Index
Vertex-Edge Incident Matrix
Opis:
In a rectilinear route, a moving sink is restricted to travel either horizontally or vertically along the connecting edges. We present a new algorithm that finds the shortest round trip rectilinear route covering the specified nodes in a grid based Wireless Sensor Network. The proposed algorithm determines the shortest round trip travelling salesman path in a two-dimensional grid graph. A special additional feature of the new path discovery technique is that it selects that path which has the least number of corners (bends) when more than one equal length shortest round trip paths are available. This feature makes the path more suitable for moving objects like Robots, drones and other types of vehicles which carry the moving sink. In the prosed scheme, the grid points are the vertices of the graph and the lines joining the grid points are the edges of the graph. The optimal edge set that forms the target path is determined using the binary integer programming.
Źródło:
International Journal of Electronics and Telecommunications; 2019, 65, 2; 267-276
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of vessel traffic flows on a waterway bend
Autorzy:
Przywarty, M.
Dzwonkowski, J.
Powiązania:
https://bibliotekanauki.pl/articles/135120.pdf
Data publikacji:
2017
Wydawca:
Akademia Morska w Szczecinie. Wydawnictwo AMSz
Tematy:
vessel traffic flows
traffic intensity
fairway width
fairway bend
Opis:
This paper presents preliminary results of research to develop a method of analysis of chosen parameters of vessel traffic flows on a bend in a waterway. Assumptions within the model are based on the geometrical dependences and, for a significant part, on expert experience and real life manoeuvring tactics. The work is focused on the analysis of coordinates of a ship, reduced to its centre of gravity, for different input and assumed output parameters. The proposed method allows also for the analysis of other parameters that influence navigational safety such as rate of turn. The results confirm the possibility of assessment of traffic flow parameters with use of the developed method. In the next stages of the work, algorithms which are capable of accounting for human factors and external conditions can be implemented.
Źródło:
Zeszyty Naukowe Akademii Morskiej w Szczecinie; 2017, 50 (122); 68-74
1733-8670
2392-0378
Pojawia się w:
Zeszyty Naukowe Akademii Morskiej w Szczecinie
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The coefficient of head loss at the pipe bend 90° with the sliced bend
Autorzy:
Abduh, Moh
Suhardjono, Suhardjono
Sumiadi, Sumiadi
Dermawan, Very
Powiązania:
https://bibliotekanauki.pl/articles/293330.pdf
Data publikacji:
2020
Wydawca:
Instytut Technologiczno-Przyrodniczy
Tematy:
direction change
head loss
loss coefficient
pipeline network
sliced bend
slice numbers
Opis:
The head loss is a decrease in compressive height caused by friction and direction changes of flow at the sliced bend. This method expected to provide is easy, fast, and economical. The elements of influence are the velocity of flow, the number of slices, average length of sliced walls, angle changes of the sliced, coefficient of friction, acceleration of gravity, and slope of the pipe. Equation for coefficient of head loss (Kb) is an analysis method for the head loss (hL) calculation. The analysis results that have obtained are the larger diameter of the pipe, and the more slices with a fixed discharge, the coefficient of hL becomes small. Conversely, if the diameter of the pipe is getting smaller, and the slice is getting less, then the coefficient of hL becomes bigger. This method, expected to give new knowledge in pipeline network applications, especially for the large diameter of pipelines.
Źródło:
Journal of Water and Land Development; 2020, 46; 1-9
1429-7426
2083-4535
Pojawia się w:
Journal of Water and Land Development
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Ovality in Inlet Pigtail Pipe Bends Under Combined Internal Pressure and in-Plane Bending for Ni-Fe-Cr B407 Material
Autorzy:
Ramaswami, P.
Senthil Velmurugan, P.
Rajasekar, R.
Powiązania:
https://bibliotekanauki.pl/articles/352083.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
ovality
inlet pigtail pipe bend
reformer
finite element analysis
in-plane bending
Opis:
The present paper makes an attempt to depict the effect of ovality in the inlet pigtail pipe bend of a reformer under combined internal pressure and in-plane bending. Finite element analysis (FEA) and experiments have been used. An incoloy Ni-Fe-Cr B407 alloy material was considered for study and assumed to be elastic-perfectly plastic in behavior. The design of pipe bend is based on ASME B31.3 standard and during manufacturing process, it is challenging to avoid thickening on the inner radius and thinning on the outer radius of pipe bend. This geometrical shape imperfection is known as ovality and its effect needs investigation which is considered for the study. The finite element analysis (ANSYS-workbench) results showed that ovality affects the load carrying capacity of the pipe bend and it was varying with bend factor (h). By data fitting of finite element results, an empirical formula for the limit load of inlet pigtail pipe bend with ovality has been proposed, which is validated by experiments.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 3; 1881-1887
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optimizing the Structure of Vector Bend and Strain Sensor on the Base of Three-Core Microstructured Fiber
Autorzy:
Goncharenko, I.
Marciniak, M.
Konojko, A.
Reabtsev, V.
Powiązania:
https://bibliotekanauki.pl/articles/307596.pdf
Data publikacji:
2012
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
fiber bend
method of lines
microstructured fiber
mode field distribution
multicore fiber
optical sensor
Opis:
In the paper the optical sensor allowing measuring a direction, values and localization of bends and stresses in building structures is described. The sensitive element of the sensor is the microstructured fiber with three cores. The use of three-core fiber makes it possible to define the direction of deformation. Distribution of mode fields in fiber cores depending on fiber structure and bend value and direction is analyzed. The optimization of the sensitive element parameters depending on the application is proposed.
Źródło:
Journal of Telecommunications and Information Technology; 2012, 4; 63-69
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of shear stress distribution in a 90 degree channel bend
Autorzy:
Lee, S. K.
Dang, T. A.
Le, V. T.
Powiązania:
https://bibliotekanauki.pl/articles/265109.pdf
Data publikacji:
2019
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
zginanie
naprężenie ścinające
erozja
experimental channel
90 degree bend
shear stress
erosion
deposition
Opis:
Shear stress is a key parameter that plays an important role in sediment transport mechanisms; therefore, understanding shear stress distribution in rivers, and especially in river bends, is necessary to predict erosion, deposition mechanisms and lateral channel migration. The aim of this study is to analyze the shear stress distribution near a river bed at 90-degree channel bend using a depth-average method based on experimental measurement data. Bed shear stress distribution is calculated using the depth-averaged method based on velocity components data has been collected from a 3D-ADV device (three-dimensional acoustic doppler velocity) at different locations of a meandering channel. Laboratory experiments have been made at the hydraulic laboratory of the RCRFIDF (Research Center for River Flow Impingement and Debris Flow), Gangneung-Wonju National University, South Korea to provide data for simulating the incipient motion of the riverbed materials and then predicting the river morphological changes in the curved rivers. The calculated results show that the maximum value of shear stress distribution near the riverbed in the different cross sections of the surveyed channel occurs in a 70-degree cross section and occurs near the outer bank. From the beginning of a 40-degree curved channel section, the maximum value of the shear stress occurs near the outer bank at the end of the channel.
Źródło:
International Journal of Applied Mechanics and Engineering; 2019, 24, 1; 213-220
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-8 z 8

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