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Tytuł:
Hydraulic Research of Sediment Transport in the Vertical Slot Fish Passes
Autorzy:
Mumot, J.
Tymiński, T.
Powiązania:
https://bibliotekanauki.pl/articles/124389.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
vertical slot fishway
physical model
flow conditions
sediment
Opis:
The physical model of vertical slot fishway was conducted. On the fishway a device used for sediment dispense was installed. The sediment was dispensed to each chamber. Measurements of approx. height of the water table, measurements of flow rate, observation of line streams in chambers were carried out during the studies. The flows of sediment and hydraulic parameters inside designed fishway, single compartments and their connection with sedimentation process in individual chambers were also studied. the obtained research results constitute starting point for experimental analyses and research analyses. Based on the observation and measurements it is possible to state that the constructed physical model reflects the activity conditions of the vertical slot fishway. During the studies a place of deposition in sediments of individual fishway chambers were determined.
Źródło:
Journal of Ecological Engineering; 2016, 17, 1; 143-148
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Effect of Angle of Attack and Flow Conditions on Turbulent Boundary Layer Noise of Small Wind Turbines
Autorzy:
Afanasieva, N.
Powiązania:
https://bibliotekanauki.pl/articles/177922.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
wind turbine
airfoil self-noise
turbulent boundary layer
flow conditions
angle of attack
Opis:
The article aims to solve the problem of noise optimization of small wind turbines. The detailed analysis concentrates on accurate specification and prediction of the turbulent boundary layer noise spectrum of the blade airfoil. The angles of attack prediction for a horizontal axis wind turbine (HAWT) and the estimation based on literature data for a vertical axis one (VAWT), were conducted, and the influence on the noise spectrum was considered. The 1/3-octave sound pressure levels are obtained by semi-empirical model BPM. Resulting contour plots show a fundamental difference in the spectrum of HAWT and VAWT reflecting the two aerodynamic modes of flow that predefine the airfoil self-noise. Comparing the blade elements with a local radius of 0.875 m in the HAWT and VAWT conditions the predicted sound pressure levels are the 78.5 dB and 89.8 dB respectively. In case of the HAWT with predicted local angle of attack ranging from 2.98º to 4.63º, the acoustic spectrum will vary primarily within broadband frequency band 1.74–20 kHz. For the VAWT with the local angle of attack ranging from 4º to 20º the acoustic spectrum varies within low and broadband frequency bands 2 Hz – 20 kHz.
Źródło:
Archives of Acoustics; 2017, 42, 1; 83-91
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Badania modelowe hydraulicznych warunków przepływu w przepławce z zabudową roślinną
Model tests of hydraulic flow conditions in the vegetation build-up fishway
Autorzy:
Tymiński, T.
Mumot, J.
Powiązania:
https://bibliotekanauki.pl/articles/950013.pdf
Data publikacji:
2015
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
przepławki dla ryb
hydrauliczne warunki przepływu
badania modelowe
fishway
flow conditions
hydraulic model investigations
Opis:
Działania mające na celu zachowanie „korytarzy ekologicznych” w rzekach są zagadnieniem trudnym i złożonym, które wymaga wiedzy specjalistycznej z wielu dyscyplin nauki. Jednym z ważniejszych rozwiązań zapewniających ciągłość ekologiczną rzek są przepławki dla ryb, zwłaszcza te o charakterze naturopodobnym. Cechą charakterystyczną ich budowy jest zastosowanie naturalnego budulca (kamienie, pnie drzew, żwir, roślinność) w taki sposób, by swoim wyglądem przypominały małe cieki naturalne. Projektowanie hydrauliczne przepławek oparte wyłącznie na kryteriach prędkości dopuszczalnych v oraz parametru jednostkowej energii wody E, nie daje pełnej informacji o skuteczności działania tych urządzeń. W celu wytworzenia w przepławce optymalnych dla ichtiofauny warunków przepływu przydatne są badania struktury przestrzennej parametrów hydraulicznych np. zaburzeń pola prędkości lub rozkładów stopnia turbulencji Tu. W pracy zaprezentowano przykład takich badań, które autorzy przeprowadzili na modelu przepławki seminaturalnej w laboratorium wodnym IIŚ UP we Wrocławiu. Otrzymane wyniki posłużyły do oceny poprawności funkcjonowania przepławki. Badana przepławka z zabudową roślinną w formie rygli i komór spełnia wymogi hydrauliczne dla migrującej ichtiofauny i stanowi ciekawą, proekologiczna alternatywę do „ciężkiej” zabudowy technicznej.
Our engineering activity aiming at keeping ecological corridors in rivers are a difficult and complex issue that requires specialist knowledge in many disciplines. One of the installations for ensuring ecological continuum river are fishways, particularly their “near-natural” designs. They resemble mountain streams and creeks. Natural materials, such as wood, vegetation, gravel, stones and rocks are used for their construction. Design of hydraulic fishways based solely on the criteria of maximum speed v max and parameter of unitary energy of water E, it does not give complete information about the effectiveness of these devices. In order to produce the optimal flow conditions for ichthyofauna, very useful are spatial structure research of hydraulic parameters, such as disorders of flow velocity field or distributions of the turbulence number Tu. The article presents an example of such a study, which the authors carried out on the model seminatural fishway in the water laboratory in Institute of Environmental Engineering in Wrocław. The results were used to assess the accuracy of the functioning of the fishway. The tested combination of “vegetated baffles” and “pools” in the fishway model was found to be optimal for the ichthyofauna. Vegetation build-up in fishways is an interesting and proecological alternative for “heavy” technical build-up.
Źródło:
Inżynieria Ekologiczna; 2015, 44; 227-234
2081-139X
2392-0629
Pojawia się w:
Inżynieria Ekologiczna
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Extended Reynolds analigy for different flow conditions of the heated plate
Rozszerzona analogia Reynoldsa w warstwie przyściennej na grzanej płycie w różnych warunkach opływu
Autorzy:
Wierciński, Z.
Kaiser, M.
Żabski, J.
Powiązania:
https://bibliotekanauki.pl/articles/213050.pdf
Data publikacji:
2007
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Lotnictwa
Tematy:
rozszerzona analogia Reynoldsa
warstwa przyścienna
grzana płyta
różne warunki opływu
extended Reynolds analogy
different flow conditions
heated plate
Opis:
The investigation of the extended Reynolds analogy of the transitional boundary layer on the heated plate with different onflow condition was carried out. The coefficients of intermittency were determined on the basis of the tree-parametric cumulative distribution function of Weibull using the local shear stress Cf and Stanton number St distributions along the plate which are experimentally measured. For the unsteady flow with wakes the extended Reynolds analogy coefficient s is equal to 1.10 while for the flow without unsteadiness it is equal to 1.0. Finally, using the cumulative distribution function of Weibull the formula was proposed for the Prandtl number distribution in the region of laminar-turbulent transition.
W pracy przedstawiono rezultaty badań rozszerzonej analogii Reynoldsa w warstwie przyściennej na grzanej płycie w różnych warunkach jej opływu. Na podstawie pomiarów lokalnego współczynnika oporu Cf oraz liczby Stantona wzdłuż płyty w strumieniach o różnym poziomie turbulencji wyznaczono rozkład współczynnika intermitencji jako trójparametrowej dystrybuanty rozkładu Weibulla. Dla niestacjonarnego przepływu ze śladami spływowymi wartość współczynnika rozszerzonej analogii Reynoldsa wynosi 1.10, zaś w pozostałych badanych przypadkach wartość tego współczynnika wynosi 1. Ponadto, zaproponowano zastosowanie rozkładu współczynnika intermitencji w postaci dystrybuanty trójparametrowego rozkładu Weibulla do wyznaczenia rozkładu liczby Prandtla w obszarze przejścia laminarno-turbulentnego w warstwie przyściennej dla przepływów o różnym poziomie niestacjonarności.
Źródło:
Prace Instytutu Lotnictwa; 2007, 4(191); 83-91
0509-6669
2300-5408
Pojawia się w:
Prace Instytutu Lotnictwa
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analiza wpływu kształtu stożkowatej części prądownicy na jej właściwości hydrauliczne
Analysis of the shape of the conoidal part of the fire-hose nozzle on its hydraulic properties
Autorzy:
Przydatek, M.
Powiązania:
https://bibliotekanauki.pl/articles/136653.pdf
Data publikacji:
2018
Wydawca:
Szkoła Główna Służby Pożarniczej
Tematy:
instalacja wodociągowa przeciwpożarowa
prądownica
straty ciśnienia
warunki przepływu
strumień wody
plumbing water supply installation
fire-hose nozzle
pressure losses
flow conditions
stream of water
Opis:
W skład hydrantu wewnętrznego wchodzi: wąż, zawór odcinający oraz prądownica. O charakterze swobodnego strumienia wody decyduje kształt (profil) nasadki z przewodu zasilającego. Celem artykułu jest analiza wpływu kształtu stożkowatej części prądownicy, poprzedzającej pyszczek, na jej właściwości hydrauliczne obejmujące prędkość i przyspieszenie strumienia na kierunku przepływu, a także straty ciśnienia wywołane oporami tarcia. W rozważaniach przyjęto trzy rodzaje tworzącej części stożkowatej: w postaci linii wklęsłej, prostej (stożek) oraz wypukłej. Zwrócono także uwagę na oddziaływanie kształtu stożkowatego na kontrakcję wewnętrzną strumienia we wstawce uspokajającej (pyszczku), co ma istotny wpływ na zwartość strumienia wypływającego z prądownicy. Na podstawie przeprowadzonych obliczeń i analiz stwierdzono, że prądownica o wypukłej tworzącej jest najkorzystniejszym rozwiązaniem z punktu widzenia minimalizacji oporów tarcia, zaś wpływ stosowanych długości pyszczka ma drugorzędne znaczenie. Z praktycznego punktu widzenia, pewnym wyzwaniem przy wymiarowaniu części zbieżnej prądownicy pozostaje dobór krzywizny wypukłości, co wiąże się z przyjęciem wartości wykładnika funkcji krzywizny c > 1.
A typical hydrant installation includes a hose, a shut-off valve and a nozzle. The construction of a fire-hose nozzle determines the character of free water stream. The aim of the article is to analyse the impact of the shape of conoidal part of the fire-hose nozzle on its hydraulic properties, including: speed and acceleration of stream in the flow direction, as well as the pressure losses due to the frictional resistance. Three types of the conoidal part of the fire-hose nozzle: in the form of a concave, straight and convex line, were taken in the considerations. Attention was also paid to the flow conditions, in the cylindrical outlet section (fire extinguisher nozzle) which has a significant impact on the content of the stream flowing out of the fire-hose nozzle. Based on the calculations and analyses carried out, it was found out that the convex fire-hose nozzle is the most favourable solution from the point of view of minimizing the frictional resistance. The impact of the length of fire extinguisher nozzle on the pressure losses is of the secondary importance. From the practical point of view, a certain challenge when dimensioning the conical part of the fire-hose nozzle remains the selection of curvature, which is related to the value of the exponent c> 1.
Źródło:
Zeszyty Naukowe SGSP / Szkoła Główna Służby Pożarniczej; 2018, 1, 66; 77-96
0239-5223
Pojawia się w:
Zeszyty Naukowe SGSP / Szkoła Główna Służby Pożarniczej
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The effect of crosslinking conditions on the dynamic viscosity of organosilicon polymers
Autorzy:
Nowacka, Agnieszka
Klepka, Tomasz
Powiązania:
https://bibliotekanauki.pl/articles/109560.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
abrasive flow machining
organosilicon polymers
abrasive medium
crosslinking conditions
Opis:
This study presents research concerning the development of an organosilicon polymer medium (polymethylhydroborosiloxane), that allows for the optimal selection of viscosity in the medium, for use as an admixture abrasive paste for abrasive flow machining. Based on the results of actual dynamic viscosity medium measurements, the influence of changes in temperature (25 °C, 50 °C and 75 °C) and in the concentration of the crosslinking solution (anhydrite boric acid – 2 wt.%, 4 wt.% and 6 wt.%) were studied. A number of crosslinking medium experiments were carried out, in which the characteristics of storage modulus G' and loss modulus G" of the medium containing different concentrations of crosslinking solutions at different temperature were determined. Due to the results obtained, it was possible to select the parameters of the crosslinking solution optimally both in terms of the temperature (50 °C) as well as its concentration (4 wt.%).
Źródło:
Physicochemical Problems of Mineral Processing; 2019, 55, 6; 1557-1567
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Desulfurization of Crude Oil by Laboratory Developed Multipumping Flow Injection Analysis System with Optimization by Response Surface Methodology
Autorzy:
Hadi, Ahmed Abdulrazzaq
Ali, Ali Abdulkhabeer
Khathi, Mohammed Turki
Powiązania:
https://bibliotekanauki.pl/articles/2202370.pdf
Data publikacji:
2023
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
multi-pumping flow system
desulfurisation
response surface
optimal conditions
Opis:
Sour crude oil is the crude oil that contains a high level of sulfur impurity. It can be toxic and corrosive. Before this lower-quality crude can be processed into other crude oil derivatives, the sulfur content must be reduced, raising the processing cost. A homemade semi-automated multipumping flow analysis system was constructed, consisting of several parts available on the local markets and at low economic costs to decrease the sulfur content of crude oil samples collected. The central composite design (CCD) and response surface methodology (RSM) have been used for modeling and optimization. The effects of the operational parameters, including polar and nonpolar solvent types, solvent flow rates (10–40 ml/min), mixing coil lengths (120–200 min), temperature (30–60 °C), and solvent entry time to the system (0–60 sec) were studied. Experimental and theoretical applications were made to determine the optimal sulfur content, which came out to be 1.438 and 1.395 wt.%, respectively. This system evaluated the effectiveness of the sulfur removal content for actual heavy crude oil by experimentally and theoretically to be 65.73 and 66.75% respectively. The semi-automated system was applied successfully to reduce the sulfur content in a highly sensitive and accurate way.
Źródło:
Journal of Ecological Engineering; 2023, 24, 2; 328--339
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Multifrequency-based non-linear approach to analyzing implied volatility transmission across global financial markets
Autorzy:
Boateng, Ebenezer
Asafo-Adjei, Emmanuel
Gatsi, John Gartchie
Gherghina, Ştefan Cristian
Simionescu, Liliana Nicoleta
Powiązania:
https://bibliotekanauki.pl/articles/19322599.pdf
Data publikacji:
2022
Wydawca:
Instytut Badań Gospodarczych
Tematy:
shocks transmission
information flow
Rényi transfer entropy
multi-scale
market conditions
Opis:
Research background: The contagious impact of the COVID-19 pandemic has heightened financial market's volatility, nonlinearity, asymmetric and nonstationary dynamics. Hence, the existing relationship among financial assets may have been altered. Moreover, the level of investor risk aversion and market opportunities could also alter in the pandemic. Predictably, investors in the heat of the moment are concerned about minimizing losses. In order to determine the level of hedge risks between implied volatilities in the COVID-19 pandemic through information flow, it is required to take into account the increased vagueness of economic projections as well as the increased uncertainty in asset values as a result of the pandemic. Purpose of the article: The study aims to examine the transmission of information between the VIX-implied volatility index for S&P 500 and fifteen other implied volatility indices in the COVID-19 pandemic. Methods: We relied on daily changes in the VIX and fifteen other implied volatility indices from commodities, currencies, and stocks. The study employed the improved complete ensemble empirical mode decomposition with adaptive noise which is in line with the heterogeneous expectations of market participants to denoise the data and extract intrinsic mode functions (IMFs). Subsequently, we clustered the IMFs based on common features into high, low, and medium frequencies. The analysis was carried out using Rényi transfer entropy (RTE), which allowed for the evaluation of both linear and non-linear, as well as varied distributions of the market dynamics. Findings & value added: Findings from the RTE revealed a bi-directional flow of negative information amid the VIX and each of the volatility indices, particularly in the long term. We found this behavior of the markets to be consistent at varying levels of investors' risk aversion. The findings help investors with their portfolio strategies in the time of the pandemic, which has resulted in fluctuating levels of risk aversion. Our findings characterize global financial markets to be "non-linear heterogeneous evolutionary systems". The results also lend support to the emerging delayed volatility of market competitiveness and external shocks hypothesis.
Źródło:
Oeconomia Copernicana; 2022, 13, 3; 699-743
2083-1277
Pojawia się w:
Oeconomia Copernicana
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Shock wave induced flow separation control by Air-Jet and Rod Vortex Generators
Autorzy:
Tejero, F.
Doerffer, P.
Szulc, O.
Powiązania:
https://bibliotekanauki.pl/articles/1938633.pdf
Data publikacji:
2015
Wydawca:
Politechnika Gdańska
Tematy:
airfoil
boundary layer
flow control
separation
shock wave
transonic conditions
vortex generator
Opis:
Flow separation control by Vortex Generators (VGs) has been analyzed over the last decades. The majority of the research concerning this technology has been focused on subsonic flows where its effectiveness for separation reduction has been proven. Less complex configurations should be analyzed as a first step to apply VGs in transonic conditions, commonly present in many aviation applications. Therefore, the numerical investigation was carried out for a Shock Wave-Boundary-Layer Interaction (SWBLI) phenomenon inducing strong flow separation at the suction side of the NACA 0012 profile. For this purpose, two kinds of VGs were analyzed: well documented Air-Jet Vortex Generators (AJVGs) and our own invention of Rod Vortex Generators (RVGs). The results of the numerical simulations based on the RANS approach reveal a large potential of this passive flow control system in delaying stall and limiting separation induced by a strong, normal shock wave terminating a local supersonic area.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2015, 19, 2; 167-180
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hydromorphological Effect of Introducing Small Water Structures in River Restoration – the Example of PBHS Implementation
Autorzy:
Kałuża, T.
Szoszkiewicz, K.
Szałkiewicz, E.
Powiązania:
https://bibliotekanauki.pl/articles/123707.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
river restoration
hydromorphology
river flow pattern
hydrodynamic conditions
plant basket hydraulic structure
Opis:
The work attempts to determine the impact of small hydrotechnical structures on channel hydromorphology as a measure of river restoration. The experiment was set up in Flinta River in Polish lowland where extensive hydromorphological survey was competed. At the first stage of restoration project containers filled with plant clumps working as sediment traps (plant basket hydraulic structures – PBHS) were introduced. Those structures were relatively small but at the same time, large enough to change the river flow efficiently – working like low crested weirs. Two year monitoring program provided information about the impact of introducing such structures on river morphology and explained the PBHS impact on flow pattern of the river.
Źródło:
Journal of Ecological Engineering; 2016, 17, 2; 90-96
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An overview of heat transfer enhancement based upon nanoparticles influenced by induced magnetic field with slip condition via finite element strategy
Autorzy:
Hafeez, Muhammad B.
Krawczuk, Marek
Shahzad, Hasan
Powiązania:
https://bibliotekanauki.pl/articles/2105987.pdf
Data publikacji:
2022
Wydawca:
Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Tematy:
magnetohydrodynamic flow
porous medium
nanofluids
heat transfer
thermal performance
convective boundary conditions
FEM
Opis:
The mathematical model of heat generation and dissipation during thermal energy transmission employing nanoparticles in a Newtonian medium is investigated. Dimensionless boundary layer equations with correlations for titanium dioxide, copper oxide, and aluminium oxide are solved by the finite element method. Parameters are varied to analyze their impact on the flow fields. Various numerical experiments are performed consecutively to explore the phenomenon of thermal performance of the combination fluid. A remarkable enhancement in thermal performance is noticed when solid structures are dispersed in the working fluid. The Biot number determines the convective nature of the boundary. When the Biot number is increased, the fluid temperature decreases significantly. Among copper oxide, aluminium oxide, and titanium oxide nanoparticles, copper oxide nanoparticles are found to be the most effective thermal enhancers.
Źródło:
Acta Mechanica et Automatica; 2022, 16, 3; 200--206
1898-4088
2300-5319
Pojawia się w:
Acta Mechanica et Automatica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A boundary condotions at modeling 1-D pulsating flows in pipes according to the method of characteristics
Autorzy:
Pałczyński, T.
Powiązania:
https://bibliotekanauki.pl/articles/246623.pdf
Data publikacji:
2012
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
1D simulations
Valve boundary conditions
method of characteristics
pulsating flow at pipes
Opis:
At this paper, there were compared three conceptions of boundary conditions and their definition at partially opened pipes. This is typical at inlet and exhaust pipes of internal combustion engines and piston compressors. At an introduction there were listed the current state of affairs at a one dimensional modelling pulsations according to the Method of Characteristics (MOC). Subsequently, there was presented the main idea of MOC. At the third chapter there were presented general guidelines at initial and boundary conditions definition. Next there are three descriptions of the analyzed problem. Firstly, there was presented partially open end phenomena at space and stage plane. Secondly, there was shown the theory of acoustic wave propagation with description of stage waves at analyzed ends of pipe. Lastly, there is a new conception of constant pressure valve boundary conditions, which is the synthesis of the both mentioned earlier. At the fourth paragraph there was shortly presented existing test rig dedicated to research of pulsating flow in pipes. This test rig was built at Flow Metrology Division of Lodz University of Technology [9]. At the second part of this chapter there were shown main assumption of elaborated simulation algorithm at Matlab Simulink environment. Lastly there were discussed simulation results compared with presented conceptions of boundary conditions.
Źródło:
Journal of KONES; 2012, 19, 2; 395-402
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Traffic conditions assessment for crossing: Sandomierska - Źródłowa streets in Kielce
Ocena warunków ruchu na skrzyżowaniu ulic: Sandomierska - Źródłowa w Kielcach
Autorzy:
Stępień, M.
Powiązania:
https://bibliotekanauki.pl/articles/402334.pdf
Data publikacji:
2011
Wydawca:
Politechnika Świętokrzyska w Kielcach. Wydawnictwo PŚw
Tematy:
skrzyżowania
warunki drogowe
natężenie ruchu
ruch tranzytowy
crossing
traffic conditions
traffic flow
through traffic
Opis:
For better flow of the traffic in the cities crossings with central islands are good solution. Problems begin with overload caused by heavy urban traffic as well as through traffic. Moreover, the traffic is much heavier from year to year. The results of traffic analysis at one of the most important crossing in Kielce are presented in this paper. There are also presented the results of functionality of this crossing after amending to traffic regulation, geometry factors and program group diagram. This elaboration signalizes that the only alternative to improve traffic condition on the crossing could be an elimination some groups of users, building and ensuring an access to the beltway or rebuilding of the crossing to the other type. The elimination of through traffic from the city should automatically reduce the traffic load factor on the crossing and reinstate an acceptable traffic conditions.
Źródło:
Structure and Environment; 2011, 3, 3; 5-9
2081-1500
Pojawia się w:
Structure and Environment
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Extreme Hydrological Phenomena in the Esil River Basin: Genesis, General Patterns of Manifestation
Autorzy:
Plekhanov, Petr Andreevich
Medeu, Nadira Nusupkyzy
Powiązania:
https://bibliotekanauki.pl/articles/124716.pdf
Data publikacji:
2019
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
inundation
floods
snow-melt floods
flood control
maximum flow
factors
conditions
occurrence
air temperature
precipitation
Opis:
The research subject involves dangerous hydrological phenomena (floods) in the Esil River Basin (Akmola and North Kazakhstan regions). The aim set by the authors was to improve the theoretical knowledge about floods and inundations, in order to contribute to solving the general problem of ensuring the safety of the territories in the Esil Water Management Basin (WMB) against harmful effects of water. In Kazakhstan, floods are caused by almost all known causes in the world: in most of the country – spring floods, the high-intensity rainfall. Additionally, there were cases when floods occurred as a result of dam failures (e.g. in the case of the Kyzylagash village in the Almaty region). Annually, the damage caused by floods throughout Kazakhstan amounts to several tens of billions of tenge. The predicted increase in air temperature and precipitation, coupled with the intensive development of farmland river valleys, will undoubtedly lead to the increase in the frequency and destructive power of floods. Therefore, developing a set of measures to prevent and protect against floods constitutes an urgent task. These measures will significantly reduce the expenses for the liquidation of the flood effects. The data on extreme hydrological phenomena (EHP) in the Esil River basin were collected and systematized. The conditions for the formation of high floods on the rivers of the researched region were studied. Various “typical” scenarios of the formation of dangerous and catastrophic floods were presented. The periods of passage of snow-melt floods (high floods) and other regularities of the intra-annual water regime in the Esil river basin were determined.
Źródło:
Journal of Ecological Engineering; 2019, 20, 7; 187-195
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Characteristic parameters of soil failure criteria for plane strain conditions – experimental and semi-theoretical study
Autorzy:
Sławińska-Budzich, Justyna
Powiązania:
https://bibliotekanauki.pl/articles/1845147.pdf
Data publikacji:
2021
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
soil failure criteria
soil peak strength
plane strain conditions
true triaxial apparatus
plastic flow rule
Opis:
The paper concerns the characteristic parameters of the selected isotropic failure criteria, i.e. Mohr–Coulomb, Drucker–Prager, Matsuoka–Nakai and Lade–Duncan. The parameters are determined directly from the failure criteria and stress measurements or by semi-theoretical approach, assuming that the soil obeys the associated flow rule and using the plane strain condition. In the latter case, the parameters can be expressed as functions of the plane strain internal friction angle, which is determined from measurements. The principal stress tensor components, corresponding to the soil peak strength and necessary to obtain the failure criteria parameters, are measured in a series of true triaxial, plane strain tests, on coarse Skarpa sand samples of different initial relative density, subjected to various confining pressures.
Źródło:
Studia Geotechnica et Mechanica; 2021, 43, 3; 237-254
0137-6365
2083-831X
Pojawia się w:
Studia Geotechnica et Mechanica
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 30

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