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Tytuł:
The use of the time reverse acoustics in a shallow sea
Autorzy:
Stromkov, A. A.
Powiązania:
https://bibliotekanauki.pl/articles/331672.pdf
Data publikacji:
2008
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
acoustics
shallow sea
TRM
Opis:
In this report the results of theoretical, numerical and experimental analysis of TRM in a shallow sea are submitted. It is shown that in shallow sea the characteristics of focusing depend first of all on the sizes of the array of imaginary sources which essentially exceeds the sizes of any real array. The method of an experimental research of characteristics of TRM is founded only on the receiving elements and a probe sources is offered. The spatial sizes and the form of focal area of TRM are measuired. It is experimentally confirmed the identity of focal area of TRM with one element and the vertical arrays. The estimation of efficiency of such systems is executed.
Źródło:
Hydroacoustics; 2008, 11; 353-363
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Underwater noise properties in waterway areas of the South Baltic Sea
Autorzy:
Jaśniewicz, D.
Klusek, Z.
Neves, S.
Powiązania:
https://bibliotekanauki.pl/articles/331866.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
shipping noise
shallow sea
Opis:
Results of underwater noise records completed with single and multi-hydrophone systems performed in the shallow water in the close vicinity of shipping lanes to the Gdansk/Gdynia and Świnoujście/Szczecin harbours are presented. Due to the fact that the bottom properties, bathymetry, and temporally varying sea surface alter the original sound spectra and reduce the acoustic energy, the sound transmission losses have been modelled, and an attempt to predict source levels of ships was performed. The KRAKEN sound propagation model illustrates the problems of the recognition of sources noise spectra on the basis of observations in a far zone from the sources. On the basis of the observed noise data, jointly with the AIS system the potential ecological effects of anthropogenic underwater noise on marine organisms are given for the Pomeranian Bight. In the paper, some examples of algorithms of ship noise recognition are given.
Źródło:
Hydroacoustics; 2016, 19; 173-184
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Non-linear water waves - experiments and theory
Autorzy:
Wilde, P.
Sobierajski, E.
Sobczak, Ł.
Powiązania:
https://bibliotekanauki.pl/articles/241057.pdf
Data publikacji:
2001
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
shallow water waves
laboratory experiments
Opis:
The paper concems laboratory experiments on shallow water waves. The waves in our flume were generated as programmed groups, with gentle fading-in and fading-out of amplitudes of the wavemaker's piston's motions. The higher harmonic components have been considered in the motion. Their influence on characteristics of generated waves has also been studied. The measurements were carried out at 6 cross sections along the propagation path; both wave profiles and velocities were recorded. As a description of phenomena, the wave profiles were approximated by harmonic com-ponents according to the Stokes solution. It was noted, that parameters of harmonic components change along the propagation path; there are energy transfers between them. The higher harmonic components are more significant for the description of wave profiles, than for the velocities. The results of the experiments were used in verifications in a research program on the theoretical description and numerical al-gorithm for shallow water waves generated and propagated in a flume.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2001, 48, 2; 107-128
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical investigating the effect of water depth on ship resistance using RANS CFD method
Autorzy:
Hoa, Nguyen Thi Ngoc
Vu, Bich Ngoc
Tran, Ngoc Tu
Chien, Nguyen Manh
Le, Tat Hien
Powiązania:
https://bibliotekanauki.pl/articles/259677.pdf
Data publikacji:
2019
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
ship resistance
shallow water
RANS
Opis:
On inland waterways the ship resistance and propulsive characteristics are strictly related to the depth of the waterway, thus it is important to have an understanding of the influence of water depth on ship hydrodynamic characteristics. Therefore, accurate predictions of hydrodynamic forces in restricted waterways are required and important. The aim of this paper is investigating the capability of the commercial unsteady Reynolds– Averaged Navier–Stokes (RANS) solver to predict the influence of water depth on ship resistance. The volume of fluid method (VOF) is applied to simulate the free surface flow around the ship. The hull resistance in shallow and deep water is compared. The obtained numerical results are validated against related experimental studies available in the literature.
Źródło:
Polish Maritime Research; 2019, 3; 56-64
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An Approximate solution to the Boussinesq type equations describing periodic waves
Autorzy:
Szmidt, J. K.
Powiązania:
https://bibliotekanauki.pl/articles/240984.pdf
Data publikacji:
2003
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
Boussinesq type equations
shallow water
Opis:
The paper concerns the non-linear problem of description of shallow-water waves of finite amplitude. The description is based on the conservation-law formulation, which seems to be particularly convenient in constructing an approximate solution of the problem considered. The analysis is confined to the one-dimensional case of waves propagating in water of constant depth. In the model considered, vertical acceleration of the fluid is taken into account, and thus, the fundamental equations of the problem are similar to those given by Boussinesq (Abbott 1979). The equations differ from those frequently used in shallow-water hydrodynamics which are based on the assumption of hydrostatic pressure. An approximate solution of the problem is constructed by means of a perturbation scheme with the third order expansion of the equations with respect to a small parameter. It is demonstrated that the solution procedure may be successfully applied only within a certain range of the two ratios defining wave height to water depth and the depth to wave length, respectively.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2003, 50, 3; 269-285
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Tracking of the broadband source of the underwater noise in the very shallow water conditions
Autorzy:
Grelowska, G.
Kozaczka, E.
Powiązania:
https://bibliotekanauki.pl/articles/331537.pdf
Data publikacji:
2015
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
broadband signals
shallow water
sound propagation
Opis:
The paper contains the results, both theoretical and experimental, connected with the tracking of the underwater noise source as small ships, pontoon, diver and so on. The problem of security in the shallow water area is the challenge for underwater acousticians. In this paper there is taken into account the detection of the sources that move on the surface of the sea or underwater in shallow and very shallow water. The main goal deals with characterization of the sound propagation at the shallow water channel. The next problem is formulation of the sound propagation inside of this acoustic duct including normal mode creations and dispersion of the acoustic energy. When we take into account the small ships noise the two main sources are analyzed. The first one is the vibration energy produced by the mechanisms located inside of the ship hull. The acoustical energy is transformed through structural elements of the hull to surrounding water. This energy propagates as broadband underwater noise. The next source is the ship propeller. The sources of the underwater noise give the some deposit to the total acoustical energy that means the ambient noise. The problem that should be solved is to discover these acoustical disturbances along with their classification, identification and tracking.
Źródło:
Hydroacoustics; 2015, 18; 77-86
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental studies of low-frequency acoustic fields in a shallow sea
Autorzy:
Luchinin, A. G.
Powiązania:
https://bibliotekanauki.pl/articles/332794.pdf
Data publikacji:
2009
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
experimental studies
acoustic fields
shallow sea
Opis:
The results of the studies of excitation and propagation of low-frequency acoustic fields in a shallow sea, which have been carried out at the IAP RAS for several years, are discussed. A novel equipment complex designed specially for these experiments and intended for the selective excitation and reception of waveguide modes is described. Examples of measurements of various characteristics of low-order mode acoustic signals are given, which demonstrate high efficiency of the applied equipment and measurement technique.
Źródło:
Hydroacoustics; 2009, 12; 117-126
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Metodika ocenki dvizenia sudov na melkovodnyh ucastkah
Techniques for the assessment of ships in shallow areas
Autorzy:
Arefyev, I.
Powiązania:
https://bibliotekanauki.pl/articles/359847.pdf
Data publikacji:
2012
Wydawca:
Akademia Morska w Szczecinie. Wydawnictwo AMSz
Tematy:
transport
shallow water
ship
environment
evaluation
Opis:
A method for assessing the impact of low water in the fairway on the movement of ships in the rivers and canals is shown in the work. The growth speed of the ship breaks down the river (channel), the territory of the area. It is important that when the motion is regular. This paper is an analysis of this problem.
Źródło:
Zeszyty Naukowe Akademii Morskiej w Szczecinie; 2012, 31 (103); 19-23
1733-8670
2392-0378
Pojawia się w:
Zeszyty Naukowe Akademii Morskiej w Szczecinie
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A method of hybrid MT for related languages
Autorzy:
Homola, P.
Kubon, V.
Powiązania:
https://bibliotekanauki.pl/articles/969803.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
machine translation
related languages
shallow methods
Opis:
The paper introduces a hybrid approach to a very specific field in machine translation - the translation of closely related languages. It mentions previous experiments performed for closely related Scandinavian, Slavic, Turkic and Romanic languages and describes a novel method, a combination of a simple shallow parser of the source language (Czech) combined with a stochastic ranker of (parts of) sentences in the target language (Slovak, Russian, Slovenian). The ranker exploits a simple stochastic model of the target language and its main task is to choose the best translation among those provided by the system. The last section of the paper presents results indicating better translation quality compared to the existing MT system for Czech and Slovak and compares them with the results obtained by the translation from Czech to Russian using the same system.
Źródło:
Control and Cybernetics; 2010, 39, 2; 421-438
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
White noise excited vibrations of viscoelastic shallow shells
Autorzy:
Nizioł, J.
Kozień, M. S.
Powiązania:
https://bibliotekanauki.pl/articles/279764.pdf
Data publikacji:
2000
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
shallow shells
vibrations
viscoelasticity
white noise
Opis:
The paper presents the results of the analysis of randomly excited vibrations of viscoelestic shallow shells. The parameter of interest is the dispersion of velocity normal to the element surface. The choice of parameter is motivated by estimation of the noise generated by a vibrating panel.
Drgania lepkosprężystych powłok małowyniosłych poddanych wymuszeniu losowemu typu białego szumu W artykule omówiono rezultaty analiz drgań powłok małowyniosłych wykonanych z materiału lepkosprężystego i poddanych wymuszeniu losowemu typu białego szumu. Jako parametr opisujący drgania przyjęto dyspersję składowej prędkości normalnej do powierzchni środkowej powłoki. Wybór tego parametru jest uzasadniony faktem, iż jego wartość może być miarą wartości mocy akustycznej promieniowanej przez drgający element.
Źródło:
Journal of Theoretical and Applied Mechanics; 2000, 38, 2; 351-366
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of the vertical distribution of the sound speed of the Gulf of Gdansk in the years 2000-2010
Autorzy:
Grelowska, G.
Witos, D.
Powiązania:
https://bibliotekanauki.pl/articles/332481.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
shallow water acoustics
underwater acoustic climate
Opis:
The 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 the Southern Baltic they change during the year also in the deep water layer. They depend on the inflows of highly saline water from the Northern Sea through the Danish Straits, which evoke a dense bottom current increasing the salinity at the bottom. The vertical sound speed distribution in the Southern Baltic is strongly dependent on the hydrological conditions. In the paper the characteristic elements of acoustic climate of the Southern Baltic will be considered, based on data concerning the Gulf of Gdansk. Averaged characteristics of temperature, salinity and sound speed for the years 2000-2010, as well as anomalies, have been determined.
Źródło:
Hydroacoustics; 2016, 19; 129-137
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Two-dimensional shallow water model for rapidly and gradually varied flow
Autorzy:
Szydłowski, M.
Powiązania:
https://bibliotekanauki.pl/articles/241012.pdf
Data publikacji:
2001
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
Two-dimensional shallow water model
rapidly varied flow
gradually varied flow
shallow water equations
eddy viscosity terms
Opis:
The numerical solution of full shallow water equation (SWE) including the eddy viscosity terms is presented. In the first part of the paper the solution of the homogeneous part of SWE for discontinuous, rapidly varied flow is reported. The method presented here is based on Roe idea of numerical fluxes of mass and momentum. The numerical solution of SWE on unstructured, triangular mesh is reported and the influence of geometry approximation is examined. The imposing of the boundary condition on a triangular numerical mesh is described in detail. The consistent with finite volume method (FVM) approximation of the viscous part of SWE is presented. The procedure similar to the finite element method (FEM) is used to calculate the function derivatives inside the finite volumes. The specific difficulties of source terms numerical integration are studied and some methods to avoid these problems are presented. To integrate the bottom friction term the splitting technique is implemented. The computed results are compared to analytical solution of Saint-Venant equations, experimental data and results available in the literature. Good agreement between these results is observed.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2001, 48, 1; 35-61
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Determination of Groundwater Vulnerability Using the DRASTIC Method in Ouargla Shallow Aquifer (Algerian Sahara)
Autorzy:
Satouh, Adel
Boualem, Bouselsal
Chellat, Smaine
Benaabidate, Lahcen
Powiązania:
https://bibliotekanauki.pl/articles/1838286.pdf
Data publikacji:
2021
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
Ouargla
shallow aquifer
vulnerability
DRASTIC
land-use
Opis:
Groundwater is the main source for many uses around the city of Ouargla. In this study, the DRASTIC method was used to assess the vulnerability of the groundwater aquifer. Seven hydrogeological parameters of the model (D water depth, R efficient charging, A aquifer type, S soil type, T topography, I unsaturated zone and C hydraulic conductivity) were measured and mapped. The intrinsic vulnerability map of the shallow aquifer, using the DRASTIC method, shows a high to very high vulnerability to pollution; 91.6% of the study area has high vulnerability, 8.4% of it has very high vulnerability. The comparison of the DRASTIC maps with the land use map illustrates that the agglomerations and irrigated areas are the most vulnerable areas to pollution, due to the low depth of the aquifer and the infiltration of significant domestic and irrigation wastewater. The results show that the relationship coefficient between the DRASTIC index and nitrate concentration is R = 0.73. This indicates that the groundwater vulnerability mapping by using the DRASTIC method can be applied for sensible groundwater resources management and land-use planning in the study area.
Źródło:
Journal of Ecological Engineering; 2021, 22, 6; 12-19
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Determination of Groundwater Vulnerability Using the DRASTIC Method in Ouargla Shallow Aquifer (Algerian Sahara)
Autorzy:
Satouh, Adel
Boualem, Bouselsal
Chellat, Smaine
Benaabidate, Lahcen
Powiązania:
https://bibliotekanauki.pl/articles/1838393.pdf
Data publikacji:
2021
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
Ouargla
shallow aquifer
vulnerability
DRASTIC
land-use
Opis:
Groundwater is the main source for many uses around the city of Ouargla. In this study, the DRASTIC method was used to assess the vulnerability of the groundwater aquifer. Seven hydrogeological parameters of the model (D water depth, R efficient charging, A aquifer type, S soil type, T topography, I unsaturated zone and C hydraulic conductivity) were measured and mapped. The intrinsic vulnerability map of the shallow aquifer, using the DRASTIC method, shows a high to very high vulnerability to pollution; 91.6% of the study area has high vulnerability, 8.4% of it has very high vulnerability. The comparison of the DRASTIC maps with the land use map illustrates that the agglomerations and irrigated areas are the most vulnerable areas to pollution, due to the low depth of the aquifer and the infiltration of significant domestic and irrigation wastewater. The results show that the relationship coefficient between the DRASTIC index and nitrate concentration is R = 0.73. This indicates that the groundwater vulnerability mapping by using the DRASTIC method can be applied for sensible groundwater resources management and land-use planning in the study area.
Źródło:
Journal of Ecological Engineering; 2021, 22, 6; 12-19
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The extent of the unconfined aquifer based on the Dempster-Shafer theory on the example of postglacial sandur area
Autorzy:
Kachnic, M.
Powiązania:
https://bibliotekanauki.pl/articles/2063008.pdf
Data publikacji:
2010
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
unconfined aquifer
shallow aquifer
Dempster-Shafer theory
probabilistic
Opis:
The research aimed to present an application of the technique based on the Dempster-Shafer theory for the determination of the shallow unconfined aquifer extent in a nonparametric (probabilistic) scale. The geology of research area is predominantly composed of the Pleistocene postglacial sediments. Only unconfined aquifers were taken into account in the study described in these paper. The resulting image showed a map of the aquifers’ extents in a probabilistic scale i.e. in a range between 0 (the lack of the aquifer, which is confirmed by research) and 1 (confirms the occurrence of the aquifer proved by research). Data analyses were carried out in the Geographic Information System. All the data were imported to the IDRISI. The Dempster-Shafer probability theory supported by the module BELIEF of IDRISI software was applied to the algebra of pixel maps.
Źródło:
Biuletyn Państwowego Instytutu Geologicznego; 2010, 441 Hydrogeologia z. 10; 55--61
0867-6143
Pojawia się w:
Biuletyn Państwowego Instytutu Geologicznego
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ultra-shallow nitrogen plasma implantation for ultra-thin silicon oxynitride (SiOxNy) layer formation
Autorzy:
Bieniek, T.
Beck, R. B.
Jakubowski, A.
Kudła, A.
Powiązania:
https://bibliotekanauki.pl/articles/308830.pdf
Data publikacji:
2005
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
MOS technology
plasma processing
shallow implantation
radiation damage
Opis:
The radiation damage caused by low energy r.f. plasmas has not been, to our knowledge, studied so far in the case of symmetric planar plasma reactors that are usually used for PECVD processes. The reason is that, unlike nonsymmetrical RIE reactors, such geometry prevents, basically, high-energy ion bombardment of the substrate. In this work, we present the results of experiments in which we have studied the influence of plasma processing on the state of silicon surface. Very low temperature plasma oxidation has been used as a test of silicon surface condition. The obtained layers were then carefully measured by spectroscopic ellipsometry, allowing not only the thickness to be determined accurately, but also the layer composition to be evaluated. Different plasma types, namely N2, NH3 and Ar, were used in the first stage of the experiment, allowing oxidation behaviour caused by the exposure to those plasma types to be compared in terms of relative differences. It has been clearly proved that even though the PECVD system is believed to be relatively safe in terms of radiation damage, in the case of very thin layer processing (e.g., ultra-thin oxynitride layers) the effects of radiation damage may considerably affect the kinetics of the process and the properties of the formed layers.
Źródło:
Journal of Telecommunications and Information Technology; 2005, 1; 70-75
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the Description of Long Water Waves in Material Variables
Autorzy:
Szmidt, K.
Hedzielski, B.
Powiązania:
https://bibliotekanauki.pl/articles/241085.pdf
Data publikacji:
2009
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
long waves
shallow water
unsteady motion
sloping beach
Opis:
Shallow water equations formulated in material variables are presented in this paper. In the model considered, a three-dimensional physical problem is substituted by a two-dimensional one describing a transformation of long waves in water of variable depth. The latter is obtained by means of the assumption that a vertical column of water particles remains vertical during the entire motion of the fluid. Under the assumption of small, continuous variation of the water depth, the equations for gravity waves are derived through Hamilton's principle formulated in terms of the material coordinates. This formulation ensures the conservation of mechanical energy. The approximation depends on the wave parameters as well as on the bed bathymetry. The latter may influence a solution of the model decisively; thus, one should be careful in applying the description to complicated geometries of fluid domains encountered in engineering practice.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2009, 56, 1-2; 63-83
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ship seakeeping in UKC determination – a further study on wave force transfer functions
Autorzy:
Artyszuk, J.
Powiązania:
https://bibliotekanauki.pl/articles/359064.pdf
Data publikacji:
2012
Wydawca:
Akademia Morska w Szczecinie. Wydawnictwo AMSz
Tematy:
ship seakeeping
ocean wave
shallow water
motion dynamics
Opis:
Modeling of ship motions in waves concentrates in most applications on the response amplitude operator (RAO). This mathematically not demanding method of analysis is very attractive, but loses some essential information in certain situations. The objective of present contribution is to establish and investigate preliminary foundations for a seakeeping model as optimal for under keel clearance (UKC) estimation. A special attention was devoted to transients of motions, stationary harmonic motions, coupling between degrees of freedom, and the wave force transfer functions – all in the aspect of shallow water environment.
Źródło:
Zeszyty Naukowe Akademii Morskiej w Szczecinie; 2012, 32 (104) z. 2; 5-15
1733-8670
2392-0378
Pojawia się w:
Zeszyty Naukowe Akademii Morskiej w Szczecinie
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Free sailing model tests of evasive action manoeuvre of a river cargo motor barge in shallow waters
Autorzy:
Górski, W.
Reichel, M.
Powiązania:
https://bibliotekanauki.pl/articles/259673.pdf
Data publikacji:
2007
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
shallow water
free sailing
inland water motor barge
Opis:
The paper presents shallow water experiments of a self-propelled, free running model of an inland water motor barge. In accordance with the Rhine Manoeuvring Standards Rheinschiffsuntersuchungsordnung (RheinSchUO 1995, issue 2005), evasive action manoeuvring tests were realised. Model obtained from DST Duisburg Germany was a 5.00 meters long motor barge built to a scale of 1:20 and propelled with an 80 mm diameter ducted propeller. Tests were carried out in the auxiliary towing tank of the Ship Hydromechanics Division in Gdańsk. The experiment consisted of efficiency analysis of different rudder blades with variable rudder profiles and rudder blade areas. In total the evasive action test was repeated for three different rudder profiles, with three different chord lengths and at three different water depths each. For each particular case the total standard manoeuvre time and side rudder force was measured. These results were compared with the RheinSchUO standards. The model tests programme was realised within the EU CREATING project supported in the 6th Framework Programme.
Źródło:
Polish Maritime Research; 2007, S 2; 95-97
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the Transformation of Long Gravitational Waves in a Region of Variable Water Depth: a Comparison of Theory and Experiment
Autorzy:
Szmidt, K.
Powiązania:
https://bibliotekanauki.pl/articles/241424.pdf
Data publikacji:
2007
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
shallow water
nonlinear waves
non-uniform water depth
Opis:
The paper describes investigations on transformation of long gravitational waves in water of variable depth with reflection of the waves from a shelf barrier. In the model considered, a long water wave arrives from an area of constant water depth to an area of constant, smaller water depth, where it reflects at a vertical wall. The analysis is confined to a finite fluid domain, relevant to experimental investigations in a laboratory flume. In theoretical analysis of the phenomenon, we follow a non-linear shallow water approximation to the problem considered. The fundamental equations of fluid motion are derived with the help of a standard variational procedure in a material system of coordinates. The equations proved to be a reasonable approximation to a description of the long waves propagating in fluid with small variation of its depth. In the discussed case of reflection of such waves from a vertical barrier, however, the motion of the fluid is more complicated and therefore the long water wave theory does not deliver as good results as in the case of pure propagation of the waves. The primary objective of this paper is thus to compare the theoretical solution proposed with data obtained in experiments, and to answer the question about accuracy and applicability of the theoretical model in the description of the problem investigated.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2007, 54, 2; 137-158
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Rola płytkiego nizinnego zbiornika zaporowego w układzie "rzeka-zbiornik-rzeka" Część II. Przemiany i bilans związków fosforu w zbiorniku Słupsko
The role of shallow, lowland dam reservoir in the river-lake-river system. Part II. The phosphorus changes and budget in the Slupsko Dam-Reservoir
Autorzy:
Kostecki, M.
Nocoń, W.
Powiązania:
https://bibliotekanauki.pl/articles/296754.pdf
Data publikacji:
2010
Wydawca:
Politechnika Częstochowska. Wydawnictwo Politechniki Częstochowskiej
Tematy:
płytki zbiornik zaporowy
fosfor
shallow dam reservoir
phosphorus
Opis:
Przedstawiono wpływ płytkiego nizinnego zbiornika zaporowego Słupsko (Górny Śląsk) na zmiany stężeń i ładunków związków fosforu w Potoku Toszeckim. Zbiornik Słupsko funkcjonuje w warunkach wysokiego obciążenia zewnętrznego fosforem, co stwarza warunki dla degradacji tego ekosystemu. Bilans fosforu wykazał, że zbiornik nie zmniejsza dopływającego ładunku fosforu, zatem z punktu widzenia ochrony zbiornika Pławniowice jego rola jest niewielka. Zbiornik Słupsko na obecnym etapie swojego funkcjonowania i w aktualnych uwarunkowaniach zmienia mineralne formy fosforu na organiczne. Odwrotna zależność wielkości ładunków fosforu od wielkości przepływu na dopływie do zbiornika oraz widoczny efekt rozcieńczania wskazują na równomierne w czasie wprowadzanie do wód związków fosforu na terenie zlewni. Ustalenie źródeł pochodzenia fosforu na terenie zlewni zbiornika oraz ich eliminacja wydatnie poprawi jakość wody zarówno w Potoku Toszeckim, jak i w zbiornikach Słupsko i Pławniowice.
The influence of a shallow, lowland dam-reservoir (the Słupsko reservoir in Upper Silesia) on the changes of concentration and loads of phosphorus in the Potok Toszecki is presented. The Słupsko reservoir functions in the high phosphorus external load conditions, what causes its degradation. The phosphorus budget showed that only small amount of the phosphorus load inflowed to the reservoir is reduced. In this case the role of reservoir for protection of the Pławniowice reservoir is not important. At the present phase of the reservoir functioning and in the current environmental conditions, in the Słupsko dam-reservoir mineral forms of phosphorus change to the organic forms. The inverse function relationship between phosphorus loads and velocity of flow as well as the dilution effect show that the regular load of phosphorus is introduced from the catchment area. Location of phosphorus sources in the Słupsko dam-reservoir basin and their elimination could improve the water quality in the Potok Toszecki as well as in the Słupsko and the Pławniowice dam-reservoirs.
Źródło:
Inżynieria i Ochrona Środowiska; 2010, 13, 4; 245-257
1505-3695
2391-7253
Pojawia się w:
Inżynieria i Ochrona Środowiska
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Propagation of ship-generated noise in shallow sea
Autorzy:
Kozaczka, E.
Grelowska, G.
Powiązania:
https://bibliotekanauki.pl/articles/259166.pdf
Data publikacji:
2018
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
shallow water acoustics
propagation of acoustic waves in water layer
wave modes in shallow sea
underwater noise produced by ship
Opis:
Contamination of sea environment by noise and any energy radiated to water constitutes today a problem to which more and more attention is paid, in view, a.o., of consequences of an impact of these factors onto marine fauna. European Union has introduced a directive by which EU countries are made responsible to undertake efforts aimed at reaching a good envirenmental status of European seas by 2020. A main source of underwater noise is sea transport of any kind. Propagation of underwater acoustic disturbances in the Baltic Sea highly differs from the course of the phenomenon in a deep sea. Model of spherical propagation cannot be applied to this case in view of water environment limitation by seabed and free water surface, i.e. a reduction of the problem to wave propagation in a water layer of the depth comparable with acoustic wave length. This paper is aimed at demonstration of possible assessment of range of acoustic disturbances generated by a ship sailing in shallow sea, by using a method described in the work [13]. The research was made on the basis of results of own measurements of underwater noise produced by ships in the Gdansk Bay area. An important factor which decIdes on a range of underwater disturbances is a kind of seabed sediments. In this paper there are presented results of numerical investigations based on real data dealing with noise produced by a selected floating unit (ship) for selected characteristic spectral components. The simulations were conducted for the shallow sea model of definite physical parameters such as acoustic wave propagation velocity, geometrical dimensions (water depth) and seabed acoustic parameters as well.
Źródło:
Polish Maritime Research; 2018, 2; 37-46
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Disappeared almost without a trace : Taphonomic pathways and the recognition of hidden bioturbation events in Eocene storm deposits (Paují Formation, Lake Maracaibo, Venezuela)
Autorzy:
Buatois, L. A.
Delgado, M.
Mángano, M. G.
Powiązania:
https://bibliotekanauki.pl/articles/191974.pdf
Data publikacji:
2015
Wydawca:
Polskie Towarzystwo Geologiczne
Tematy:
trace fossils
ichnofabric
taphonomic pathways
tempestites
shallow marine
Eocene
Opis:
Shallow-marine deposits, included in the “Basal Sands” of the Eocene Paují Formation of the Maracaibo Basin in western Venezuela, record deposition in fore shore to lower off shore settings. These deposits are stacked in coarsening-upward parasequences that reflect variable intensities and frequencies of storms. Of particular interest are sharp-based, amalgamated, hummocky cross-stratified and rippled, very fine-grained sandstone beds, observed in the core MOT-X from the Motatán Field. These beds record storm deposition, under purely oscillatory to combined flows in an offshore-transition setting. The amalgamated nature of the sand stone interval indicates repeated erosion, due to multiple storm events. The ichnofabrics in these tempestites result from a distinctive taphonomic pathway, reflecting the interplay between bioturbation events and storm erosion and deposition. The storm-related trace-fossil suite is represented by Diplocraterion parallelum and local occurrences of Palaeophycus tubularis, Bergaueria isp. and Thalassinoides isp., which is consistent with the relatively high energy of formation of these deposits. Fair-weather deposits are absent from the sand stone interval. However, high densities of Chondrites isp. are present in the infills of Diplocraterion parallelum and, more rarely, Thalassinoides isp. providing the sole evidence of the establishment of a resident fauna during inter-storm intervals. Deposits containing the fair-weather suites were erosionally removed during the subsequent storm. The deep-tier emplacement of Chondrites and the ability of its producer to rework other biogenic structures favour preservation, allowing recognition of a “hidden” bioturbation event that otherwise might have remained undetected.
Źródło:
Annales Societatis Geologorum Poloniae; 2015, 85, 3; 473-479
0208-9068
Pojawia się w:
Annales Societatis Geologorum Poloniae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A nonlinear model of a turbine blade by asymptotic analysis
Autorzy:
Rodriguez, J. M.
Powiązania:
https://bibliotekanauki.pl/articles/907896.pdf
Data publikacji:
2002
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
matematyka
asymptotic analysis
nonlinear elasticity
junctions
shallow shells
multistructures
Opis:
In this paper we obtain a limit model for a turbine blade fixed to a 3D solid. This model is a three-dimensional linear elasticity problem in the 3D part of the piece (the rotor) and a two-dimensional problem (the nonlinear shallow shell equations) in the 2D part (the turbine blade), with junction conditions in the part of the turbine blade fixed to the rotor. To obtain this model, we perform an asymptotic analysis, starting with the nonlinear three-dimensional elasticity equations on all the pieces and taking as a small parameter the thickness of the blade.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2002, 12, 1; 101-113
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evaluation of shallow groundwater suitability for irrigation purposes : A case study from Doornfontein area, South Africa
Autorzy:
Moges, Simeneh S.
Dinka, Megersa O.
Powiązania:
https://bibliotekanauki.pl/articles/28411663.pdf
Data publikacji:
2023
Wydawca:
Instytut Technologiczno-Przyrodniczy
Tematy:
irrigation
Johannesburg
physico-chemical parameters
shallow groundwater
water quality
Opis:
The present study aims at evaluating the quality of shallow groundwater (SGW) and its suitability for irrigation purpose in the most urbanised part of Johannesburg city, South Africa. The SGW samples were collected in three consecutive years and analysed for 20 selected physicochemical parameters, and heavy metals. The results were compared with the South African water quality, and Food and Agricultural Organization irrigation water quality guidelines, and standard indices derived from laboratory outputs. The results of the study show that all physiochemical parameters and heavy metals were within the limits set by both guidelines for irrigation purposes, except for potassium (3.58 mg∙dm-3) and manganese levels (3.152 mg∙dm-3). The calculated irrigation parameter values of sodium adsorption ratio (SAR), sodium percentage (Na%), residual sodium carbonate (RSC), magnesium hazard (MH), Kelly’s ratio (KR) and permeability index (PI) were within the permissible range of irrigation water quality standards. The findings of this study provide helpful information for decision-makers such as utilisation of the studied groundwater for irrigation uses.
Źródło:
Journal of Water and Land Development; 2023, 58; 189--197
1429-7426
2083-4535
Pojawia się w:
Journal of Water and Land Development
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
2D Modeling of Wave Propagation in Shallow Water by the Method of Characteristics
Autorzy:
Khalilabadi, Mohammad Reza
Powiązania:
https://bibliotekanauki.pl/articles/31340098.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
wave propagation
shallow water
MOC method
waveguide
transmission loss
Opis:
In this paper, a 2D numerical modeling of sound wave propagation in a shallow water medium that acts as a waveguide, are presented. This modeling is based on the method of characteristic which is not constrained by the Courant–Friedrichs–Lewy (CFL) condition. Using this method, the Euler time-dependent equations have been solved under adiabatic conditions inside of a shallow water waveguide which is consists of one homogeneous environment of water over a rigid bed. In this work, the stability and precision of the method of characteristics (MOC) technique for sound wave propagation in a waveguide were illustrated when it was applied with the semi-Lagrange method. The results show a significant advantage of the method of characteristics over the finite difference time domain (FDTD) method.
Źródło:
Archives of Acoustics; 2022, 47, 3; 407-412
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Contribution of Soft-shelled Monothalamous Taxa to Foraminiferal Assemblages in the Adriatic Sea
Autorzy:
Sabbatini, Anna
Nardelli, Maria Pia
Morigi, Caterina
Negri, Alessandra
Powiązania:
https://bibliotekanauki.pl/articles/763441.pdf
Data publikacji:
2013
Wydawca:
Uniwersytet Jagielloński. Wydawnictwo Uniwersytetu Jagiellońskiego
Tematy:
Soft-shelled foraminifera, Allogromiids, shallow water setting, Adriatic Sea, bioindicator
Opis:
Monothalamous foraminifera with organic and agglutinated test walls (‘‘allogromiids’’ sensu lato) deserve attention because of their importance in deep-sea and shallow-water soft-bottom communities and their crucial phylogenetic position at the base of the foraminiferal evolutionary tree. However, our knowledge of the biodiversity and ecology of monothalamous foraminifera is very incomplete and geographically patchy. Here, we present a short review based on the available data on monothalamous, soft-walled foraminiferal taxa from the Adriatic Sea in response to several environmental parameters (i.e., organic matter, oxygen, grain size, depth). The main results of the studies provide evidence of the importance of these foraminiferal taxa in this shallow, temperate latitude area;they represent a start for the identification of soft-shelled monothalamous morphotypes that could be potential bioindicators of environments influenced by inputs of fresh waters, increasing eutrophication and consequent fluctuations in bottom-water oxygenation. The contribution of this soft-shelled component to living benthic foraminiferal assemblages appears not negligible and excluding it from foraminiferal studies can potentially lead to a loss of ecological information. The study, therefore, provide an atlas of the Adriatic soft-shelled foraminiferal taxa in order to 1) encourage the species-level description, if possible, or alternatively a basic morphotype characterization, 2) facilitate future comparisons of taxa from similar settings, 3) promote their potential use in future biomonitoring investigations together with the hard-shelled foraminifera.
Źródło:
Acta Protozoologica; 2013, 52, 3
1689-0027
Pojawia się w:
Acta Protozoologica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ichnology of the Cambrian Ociesęki Sandstone Formation (Holy Cross Mountains, Poland)
Autorzy:
Stachacz, M.
Powiązania:
https://bibliotekanauki.pl/articles/191282.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Geologiczne
Tematy:
Cambrian
trace fossils
shallow-water marine deposition
Holy Cross Mountains
Opis:
Quartz arenites and wackes with intercalations of silty shales of the Ociesęki Formation were analysed in small outcrops and one core. The succession contains about forty-three ichnogenera and seventy-four ichnospe- cies, among which thirty-three ichnogenera and fifty-three ichnospecies are described by present author. The formation belongs to the Schmidtiellus-Holmia Superzone and to the Protolenus-Issafeniella Zone. Most strata are totally bioturbated. The diverse and numerous trace fossils represent the Cruziana ichnofacies in the lower part of the formation and the Skolithos ichnofacies in the upper part. A few possibly new ichnospecies of different ichnogenera have been described in open nomenclature. Sedimentary structures and trace fossil assemblages indicate that the older part of this formation was deposited on the upper offshore to lower shoreface, while its younger part was deposited on the lower to middle shoreface, where storm episodes were the main factor controlling sedimentation and the activity of benthos. The trace fossil associations studied are similar to those from the lower Cambrian in many places around the world. The ichnoassociations from the Polish part of the East European Platform and from Sweden, which represent the Baltica palaeocontinent, display the closest similarity.
Źródło:
Annales Societatis Geologorum Poloniae; 2016, 86, 3; 291-328
0208-9068
Pojawia się w:
Annales Societatis Geologorum Poloniae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of the quality of shallow groundwaters on the occurrence of selected relic plant species of peatlands in the Łęczna-Włodawa Lakeland
Autorzy:
Serafin, Artur
Pogorzelec, Magdalena
Bronowicka-Mielniczuk, Urszula
Powiązania:
https://bibliotekanauki.pl/articles/292495.pdf
Data publikacji:
2020
Wydawca:
Instytut Technologiczno-Przyrodniczy
Tematy:
groundwater quality
peatlands
physical-chemical parameters
relic species
shallow groundwaters
Opis:
The aim of the study was to compare the physical-chemical quality parameters of shallow groundwater quality in peat bogs of the Łęczna-Włodawa Lake District in the context of the occurrence of selected boreal species of plant relics: dwarf birch (Betula humilis Schrank), downy willow (Salix lapponum L.) and swamp willow (Salix myrtylloides L.). Analyzes of shallow groundwater quality parameters included physical-chemical parameters: reaction (pH), electrolytic conductivity (EC), dissolved organic carbon (DOC), total nitrogen (TN), ammonium nitrogen (NH4), nitrite nitrogen (NO2), nitrate nitrogen (NO3), total phosphorus (TP), phosphate (PO4), sulfate (SO2), sodium (Na), potassium (K), calcium (Ca) and magnesium (Mg) by certified laboratory tests. It was found that the natural hydrochemical specification of peat bogs is characterized by fluctuations associated with the dynamics of internal metabolism of peat ecosystems without the visible impact of anthropopressure. This is confirmed by the concentration of nutrients: TN at the study sites were within a broad range of mean values: 16.92–45.31 mg·dm–3; NH4 (0.55–0.76 mg·dm–3); NO2 (0.06–4.33 mg·dm–3); and NO3 did not exceed 0.2 mg·dm–3, and concentration of TP adopted mean values in a range of 0.22–0.42 mg·dm–3. The studied physical-chemical factors of shallow groundwater were within the habitat preferences of the studied species, but in differentiated qualitative and quantitative ways determined optimal conditions for building the population of the studied species. Particularly values of TP lower than other obtained values in a range of: 0.08–0.32 mg·dm–3; PO4 = 0.1 mg·dm–3; TN = 2.2–21.2 mg·dm–3; NH4 = 0.1–0.46 mg·dm–3; DOC = 24.6–55.9 mg·dm–3, as well as higher than average pH values in a range of: 5.34–5.95 and concentration of Ca = 5.67–28.1 mg·dm–3 and Mg = 0.56–2.41 mg·dm–3, as well as EC = 72.1–142.3 μS·cm–1 can be treated as a condition favouring proper development of the population of dwarf birch. For Salix lapponum: a reduced level of values of nitrogen fractions (TN = 3.01–18.84 mg·dm–3; NH4 = 0.1–0.41 mg·dm–3), a reduced level of values of phosphorus fractions (TP = 0.09–0.44 mg·dm–3; PO4 = 0.1–0.44 mg·dm–3), part of ions (Ca = 4.39–19.63 mg·dm–3; Mg = 0.77–3.37 mg·dm–3), pH = 5.9–6.4, EC = 124–266 μS·cm–1 and DOC = 24.1–57.5 mg·dm–3. For the equally studied Salix myrtylloides, such conditions were met by: TP = 0.1–0.41 mg·dm–3; PO4 = 0.1–0.18 mg·dm–3, DOC = 27.5–50.9 mg·dm–3, pH = 5.3–5.94 and EC = 62.2–139.3 μS·cm–1.
Źródło:
Journal of Water and Land Development; 2020, 45; 133-142
1429-7426
2083-4535
Pojawia się w:
Journal of Water and Land Development
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Integrated sedimentological and ichnological study of the Coniacian sedimentation in North Sudetic Basin, SW Poland
Autorzy:
Leszczyński, S.
Powiązania:
https://bibliotekanauki.pl/articles/2060087.pdf
Data publikacji:
2018
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
lithofacies
ichnofacies
trace fossils
shallow marine
paralic
North Sudetic Synclinorium
Opis:
Lithofacies and ichnological features of the Coniacian deposits of the upper part of Żerkowice Member and lowest part of the overlying Czerna Formation in southeastern part of the North Sudetic Synclinorium are described and their sedimentary palaeoenvironment is interpreted. The study confirms a shallow-marine to paralic/paludine palaeoenvironment. Sedimentation of the Żerkowice Member occurred in an upper shoreface environment dominated by waves, tidal currents and wave-generated alongshore currents, with an episodic encroachment of fore shore zone and shoal-water deltas. The interpretation is supported by a high-diversity assemblage of trace fossils with 21 ichnogenera, representing a stressed expression of the Skolithos Ichnofacies dominated by Ophiomorpha nodosa and a proximal expression of the Cruziana Ichnofacies with Thalassinoides and rare specimens of diverse other ichnotaxa. Sedimentation of the Czerna Formation commenced after a stasis, with at least a local hiatus caused by emergence, and proceeded in a laterally and vertically more varied environment, with transgressive coastal lagoons evolving into freshwater lakes and marshes and with a repetitive regressive intrusion of shoreface and shoal-water deltas. The emergence of the area is recorded by coal-bearing deposits with plant-root traces. Local occurrence of the Teredolites Ichnofacies in coal (peat) deposits above the base of the Czerna Formation indicates renewed marine flooding. Continuation of the latter is locally evidenced by a trace-fossil assemblage with 17 ichnogenera, representing proximal expression of the Cruziana Ichnofacies followed by distal expression of the Skolithos Ichnofacies in the overlying transgressive-regressive cyclothems. The palaeoenvironmental changes recorded by the sedimentary succession indicate bathymetric fluctuations and imply considerable shoreline shifts and palaeogeographic changes in the basin. These changes are interpreted as a combined signal of 2nd- and 3rd-order eustatic cycles, modified and partly obliterated by the effects of intrabasinal tectonic forcing and by palaeogeographically controlled variation in sediment supply.
Źródło:
Geological Quarterly; 2018, 62, 4; 767--816
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mention Detection for Coreference Resolution in Polish. Development of the Formal Grammar
Autorzy:
Wójcicka, Alicja
Kopeć, Mateusz
Powiązania:
https://bibliotekanauki.pl/articles/677372.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Instytut Slawistyki PAN
Tematy:
coreference resolution
mention detection
shallow parsing
Formal Grammar for Polish
Opis:
Mention Detection for Coreference Resolution in Polish. Development of the Formal GrammarThis paper presents the results of an improvement and extension of the Shallow Grammar of Polish, designed for the needs of the Computer-based Methods for Coreference Resolution in Polish Texts (CORE) project. The role of the Grammar was to detect nominal groups (i.e. multi-level nested phrases) that could be considered as mentions in coreference resolution tasks. In this article, the reorganization and changes to the Grammar are described, as well as the results of an evaluation of the Polish Coreference Corpus with manual annotations of mentions and coreferential expressions. A comparison of the second version of the Grammar with an evaluation of the first version reveals an improvement to the recall and F1 measures. Parsing płytki relacji koreferencji w języku polskim. Rozwój gramatyki formalnejCelem artykułu jest przedstawienie rezultatów prac zmierzających do rozszerzenia gramatyki powierzchniowej języka polskiego, stworzonej na potrzeby projektu "Komputerowe metody identyfikacji nawiązań w tekstach polskich" (grant NCN nr 6505/B/T02/2011/40), oraz poprawy wyników jej działania. Rolą gramatyki powierzchniowej jest wykrywanie grup nominalnych, które mogą wchodzić w relację koreferencji z innymi wyrażeniami w tekście. Nowa gramatyka została przetestowana z użyciem Polskiego Korpusu Koreferencyjnego, w którym grupy nominalne oraz relacje koreferencji między nimi zostały oznaczone ręcznie. Porównanie nowej wersji gramatyki z wersją poprzednią wykazało poprawę zarówno skuteczności wykrywania odpowiednich grup, jak i wzrost miary F1.
Źródło:
Cognitive Studies; 2016, 16
2392-2397
Pojawia się w:
Cognitive Studies
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Precipitation amounts triggering landslide processes in the western part of the Nałęczów Plateau (Lublin Upland, Poland)
Autorzy:
Demczuk, Piotr
Zydroń, Tymoteusz
Szafran, Tomasz
Powiązania:
https://bibliotekanauki.pl/articles/15805023.pdf
Data publikacji:
2022
Wydawca:
Uniwersytet im. Adama Mickiewicza w Poznaniu
Tematy:
slope stability
shallow landslide
rainfall thresholds
loess
the Nałęczów Plateau
Opis:
This study covers the western part of Poland’s loess Nałęczów Plateau (Kazimierz Dolny, Zbędowice). Mass movements in the Lublin Upland occur during periods of increased precipitation or after a snowy and cold winter. To date, there are no comprehensive studies on active (precipitation, hydrology, vegetation, land use, anthropogenic factors) or passive factors (lithology, slope angle) causing such geohazards in this region. This area’s formations are characterised by high sensitivity to even small changes in moisture content; thus, their geotechnical parameters deteriorate as a result of precipitation or rising groundwater levels. The calculations in this study were chosen to determine the time necessary for ground response to external factors, in addition to determining the impact of these factors on decreases in the factor of safety (FS). Based on calculations in GeoStudio software, the impacts of rainfall totals and duration on slope failure, interpreted as an event where the FS falls below 1.0, were analysed. Accordingly, the threshold rainfall value was determined as the total rainfall at the time of slope failure. The study’s results indicate that loess covers are characterised by average water permeability, relatively high internal friction angles and low cohesion, which, combined with high slope inclination, favour landslide formation even when the slope is only partially saturated. The most unfavourable stability conditions occur at the beginning of spring, indicating that loess stability is significantly affected by snowmelt and precipitation at the beginning of the vegetation season, as well as the occurrence of episodic intense precipitation during the summer.
Źródło:
Quaestiones Geographicae; 2022, 41, 3; 33-51
0137-477X
2081-6383
Pojawia się w:
Quaestiones Geographicae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Agresywność chemiczna płytkich wód podziemnych Wrocławia
Chemical aggressiveness of shallow groundwater in Wrocław
Autorzy:
Trałka, Marta
Modelska, Magdalena
Błachowicz, Marek
Powiązania:
https://bibliotekanauki.pl/articles/2076166.pdf
Data publikacji:
2021
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
agresywność chemiczna
płytkie wody gruntowe
Wrocław
chemical aggressiveness
shallow groundwater
Opis:
Evaluation of the chemical aggressiveness of shallow ground - water for the area of Wrocław was performed in accordance with the Polish Standard (PN-EN 206+A1:2016-12). This standard requires determination of pH and concentration of ammonium, magnesium, sulphate and aggressive carbon dioxide in water. The research was carried out on 96 groundwater samples collected in the period March-May 2021 from Holocene, Pleistocene and Neogene deposits. The results show that 58% of shallow groundwater in Wrocław was aggressive towards concrete and steel. The slight (XA1), moderate (XA2) and high (XA3) aggressiveness was characteristic for 32%, 23% and 3% of the analysed waters, respectively. The significant classification factors were the concentrations of aggressive carbon dioxide, sulphate ions and, less significant, pH. The presence of magnesium and ammonium ions in groundwater did not have any classification significance because of low concentrations. The occurrence of aggressive groundwater is associated with the environment of river sediments, mainly of Holocene and Pleistocene age. Groundwater beneath till and clay formations, mainly of Pleistocene age, and of anthropogenic banks and dumps shows significantly lower aggressiveness. Aggressiveness of groundwater sampled from the aquifer covered by Neogene clay deposit is not demonstrated. The aggressiveness of Wrocław groundwater shows a mosaic space character resulting from the geological structure of the city's subsurface formations and is probably also related to the form of land development. The most aggressive ones were associated with green, agricultural and liquidated municipal waste dump areas.
Źródło:
Przegląd Geologiczny; 2021, 69, 12; 901--908
0033-2151
Pojawia się w:
Przegląd Geologiczny
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sedimentological study of the Nikolčice Formation : evidence of the Middle Jurassic transgression onto the Bohemian Massif (subsurface data)
Autorzy:
Nehyba, S.
Opletal, V.
Powiązania:
https://bibliotekanauki.pl/articles/2060331.pdf
Data publikacji:
2017
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Nikolčice Formation
Middle Jurassic
provenance
shallow marine
nearshore depositional environment
Opis:
The Jurassic sedimentary succession along the eastern margin of the Bohemian Massif starts with mostly fluvial deposits of the Gresten Formation and continues after marine transgression with the deposition of the Nikolčice Formation (Middle Jurassic, Callovian). The provenance and depositional environment of the Nikolčice Formation showed that deposition occurred within offshore, transitional zone, shoreface, foreshore and littoral sand bar environments; however, shoreface and foreshore deposits dominate in the cores studied. The crystalline units along the eastern margins of the Bohemian Massif represent the primary source of deposits of the Nikolčice Formation. An important role was played by acidic and intermediate plutonites and highly metamorphosed metasedimentary rocks (granulite and amphibolite metamorphic facies), which indicates an advanced stage of erosion of the source area. The role of volcanic and intrusive rocks was small. The primary source was followed by an additional recycled source from older sedimentary rocks (especially the Moravo-Silesian Paleozoic deposits – the Líšeň Formation, the Myslejovice Formation). A similarity of the source areas for the Nikolčice Formation and the underlying Gresten Formation was recognized. Identified differences in their source areas are mainly explained by varied erosional levels due to successive exhumation of the source Variscan orogen and possibly also by an expansion of the source area.
Źródło:
Geological Quarterly; 2017, 61, 1; 138--155
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Geneza krzemieni górnego oksfordu w Krzemionkach Opatowskich
Genesis of the Upper Oxfordian flints in Krzemionki Opatowskie, Poland
Autorzy:
Gutowski, P.
Pieńkowski, G.
Powiązania:
https://bibliotekanauki.pl/articles/2077299.pdf
Data publikacji:
2004
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
krzemionka opatowska
krzemień
shallow water carbonates
decapod burrows
sedimentary discontinuities
Opis:
Early diagenetic concretionary flint nodules from the Upper Oxfordian oolitic and micritic limestones represent silicified crustacean burrows. Their occurence is confined to very shallow carbonate facies of barrier, lagoonal, and tidal flat origin. Fills of crustacean burrows commonly provided a nucleation centre for flint formation and thereby the template on which flint nodule beds were constructed. The reason for the special relationship between flint and crustacean burrows probably lie in the original texture (high permeability) of the burrow networks and also in the organic content (including the microbial assemblages) lowering the pH. Nodule horizons are developed more or less parallel to bedding, to form several widespread horizons of the regional correlative significance.
Źródło:
Volumina Jurassica; 2004, 2, 1; 29-36
1896-7876
1731-3708
Pojawia się w:
Volumina Jurassica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Theoretical model of acoustic wave propagation in shallow water
Autorzy:
Kozaczka, E.
Grelowska, G.
Powiązania:
https://bibliotekanauki.pl/articles/258460.pdf
Data publikacji:
2017
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
shallow water acoustics
propagation of acoustic waves in water layer
Opis:
The work is devoted to the propagation of low frequency waves in a shallow sea. As a source of acoustic waves, underwater disturbances generated by ships were adopted. A specific feature of the propagation of acoustic waves in shallow water is the proximity of boundaries of the limiting media characterised by different impedance properties, which affects the acoustic field coming from a source situated in the water layer “deformed” by different phenomena. The acoustic field distribution in the real shallow sea is affected not only by multiple reflections, but also by stochastic changes in the free surface shape, and statistical changes in the seabed shape and impedance. The paper discusses fundamental problems of modal sound propagation in the water layer over different types of bottom sediments. The basic task in this case was to determine the acoustic pressure level as a function of distance and depth. The results of the conducted investigation can be useful in indirect determination of the type of bottom.
Źródło:
Polish Maritime Research; 2017, 2; 48-55
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Exact Cnoidal Solutions of the Extended KdV Equation
Autorzy:
Infeld, E.
Karczewska, A.
Rowlands, G.
Rozmej, P.
Powiązania:
https://bibliotekanauki.pl/articles/1030809.pdf
Data publikacji:
2018-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
shallow water waves
extended KdV equation
analytic solutions
inverted cnoidal waves
Opis:
The KdV equation can be derived within the shallow water limit of the Euler equations. Over the last few decades, this equation has been extended to include both higher order effects (KdV2) and an uneven river bottom. Although this equation is not integrable and has only one conservation law, exact periodic and solitonic solutions exist for the even bottom case. The method used to find them assumes the same functional forms as for KdV solutions. The KdV2 equation imposes more constraints on the parameters of solutions. Quite unexpectedly, we found two regions in m parameter space for periodic solutions. For the range of m close to one the cnoidal waves are upright as expected, but are inverted in the m region close to zero which is a completely new feature. The properties of exact solutions for KdV and KdV2 are compared. Numerical evolution of all the discussed exact solutions to KdV2 is stable and confirms the properties of the analytic solutions.
Źródło:
Acta Physica Polonica A; 2018, 133, 5; 1191-1199
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Shallow Layer Convolutional Features with Correlation Filters for UAV Object Tracking
Autorzy:
Syihabuddin, Budi
Wibowo, Suryo Adhi
Prasetyo, Agus D.
Saputri, Desti Madya
Powiązania:
https://bibliotekanauki.pl/articles/2142310.pdf
Data publikacji:
2022
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
CNN
convolutional features
correlation filter
object tracking
shallow layer
UAV tracking
Opis:
In this paper, convolutional shallow features are proposed for unmanned aerial vehicle (UAV) tracking. These convolutional shallow features are generated by pre-trained convolutional neural networks (CNN) and are used to represent the target objects. Furthermore, to estimate the location of the target objects, an adaptive correlation filter based on the Fourier transform is used. This filter is multiplied with the convolutional shallow features by using pixel-wise multiplication in the Fourier domain. Then, the inverse of Fourier is performed to estimate the location of the target object, where its location is represented by the maximum value of the response map. Unfortunately, the target object always changes its appearance during tracking. Therefore, we proposed an updated model to address this issue. The proposed method is evaluated by using the UAV123 10fps benchmark dataset. Based on the comprehensive experimental results, the proposed method performs favorably against state-of-the-art tracking algorithms.
Źródło:
Journal of Telecommunications and Information Technology; 2022, 2; 49--57
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Two-dimensional modelling of wave motion in shallow-water areas
Autorzy:
Kapiński, J.
Powiązania:
https://bibliotekanauki.pl/articles/241315.pdf
Data publikacji:
2004
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
swash zone
shallow water
wave transformation
Lagrangian approach
two-dimensional model
Opis:
A new mathematical model for prediction of a two-dimensional wave motion in shallow water is presented herein. It can be applied to investigate shoaling, diffraction, refraction, breaking, bottom friction and wave run-up on a beach, as well as mass transport and orbital motion. The model also includes an oblique wave approach to the shore and irregular bottom topography. Such engineering constructions as seawalls, breakwaters and groins are simulated numerically. Simple results of computations, shown in graphic form, indicate possible practical applications of the model.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2004, 51, 1; 3-24
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Observation and Modelling on the Shipping Noise in Shallow Waters with Complex Islands and Reefs of the East China Sea
Autorzy:
Peng, Zilong
Zhou, Fulin
Fan, Jun
Wang, Bin
Wen, Huabing
Powiązania:
https://bibliotekanauki.pl/articles/1953475.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
shipping noise
spectral source level
noise mapping
shallow water
merchant ship
Opis:
The impact of the noise radiated from merchant ships on marine life has become an active area of research. In this paper, a methodology integrating observation at a single location and modelling the whole noise field in shallow waters is presented. Specifically, underwater radiated noise data of opportunistic merchant ships in the waters of Zhoushan Archipelago were collected at least one day in each month from January 2015 to November 2016. The noise data were analyzed and a modified empirical spectral source level (SSL) model of merchant ships was proposed inspired by the RANDI-3 model (Research Ambient Noise Directionality) methodology. Then combining the modified model with the realistic geoacoustic parameters and AIS data of observed merchant ships, the noise mappings in this area were performed with N × 2D of Normal Mode calculations, in which the SSL of each ship was estimated using the modified model. The sound propagation at different receiving positions is different due to the shielding effect of islands and bottom topography. The methodology proposed in this paper may provide a reference for modelling shipping noise in shallow waters with islands and reefs.
Źródło:
Archives of Acoustics; 2021, 46, 2; 301-311
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Model experiments to assess effect of cavities on bearing capacity of two interfering superficial foundations resting on granular soil
Autorzy:
Saadi, Djamel
Abbeche, Khelifa
Boufarh, Rafik
Powiązania:
https://bibliotekanauki.pl/articles/1845136.pdf
Data publikacji:
2020
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
bearing capacity
shallow foundation
cavity
interference effect
model test
granular soil
Opis:
The objective of this paper is to describe the effect of cavities on the bearing capacity of two interfering footings based on granular soil using an exclusively experimental approach with a test model designed in the laboratory. The experimental protocol was carried out based on the variation of several parameters such as the spacing (x) (axis to axis) between the footings, and the distance (H) between the footings and cavities and between the cavities axes (L). The results highlight the effect of cavities and the interference of two strip footings on the bearing capacity factor (q) and efficiency factor (EF). Moreover, the results revealed that, in the case wherein the distance between the footings and the cavity is greater than 3, the cavity impact is eliminated.
Źródło:
Studia Geotechnica et Mechanica; 2020, 42, 3; 222-231
0137-6365
2083-831X
Pojawia się w:
Studia Geotechnica et Mechanica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis and Modelling on Radiated Noise of a Typical Fishing Boat Measured in Shallow Water Inspired by AQUO Project’s Model
Autorzy:
Peng, Z.
Fan, J.
Wang, B.
Powiązania:
https://bibliotekanauki.pl/articles/177092.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
radiated noise
South China Sea
predicted model
shallow water
transmission loss
Opis:
The shipping noise near channels and ports is an important contribution to the ambient noise level, and the depth of these sites is often less than 100 m. However less attention has been paid to the measurement in shallow water environments (Brooker, Humphrey, 2016). This paper presents extensive measurements made on the URN (underwater radiated noise) of a small fishing boat in the South China Sea with 87 m depth. The URN data showed that the noise below 30 Hz was dominated by the background noise. The transmission loss (TL) was modelled with FEM (finite element method) and ray tracing according to the realistic environmental parameters in situ. The discrepancy between the modelled results and the results using simple law demonstrates both sea surface and bottom have significant effect on TL for the shallow water, especially at low frequencies. Inspired by the modelling methodology in AQUO (Achieve QUieter Oceans) project (Audoly et al., 2015), a predicted model applied to a typical fishing boat was built, which showed that the URN at frequencies below and above 100 Hz was dominated by non-cavitation propeller noise and mechanical noise, respectively. The agreement between predicted results and measured results also demonstrates that this modelling methodology is effective to some extent.
Źródło:
Archives of Acoustics; 2018, 43, 2; 263-273
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Methods to Estimate the Channel Delay Profile and Doppler Spectrum of Shallow Underwater Acoustic Channels
Autorzy:
Nguyen, Van Duc
Nguyen, Tien Hoa
Ho, Hoa Xuan Thi
Powiązania:
https://bibliotekanauki.pl/articles/176670.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
shallow underwater acoustic
channel parameters detection
channel delay profile
Doppler spectrum
Opis:
In this paper, we present the methods to detect the channel delay profile and the Doppler spectrum of shallow underwater acoustic channels (SUAC). In our channel sounding methods, a short impulse in form of a sinusoid function is successively sent out from the transmitter to estimated the channel impulse response (CIR). A bandpass filter is applied to eliminate the interference from out-of-band (OOB). A threshould is utilized to obtain the maximum time delay of the CIR. Multipath components of the SUAC are specified by correlating the received signals with the transmitted sounding pulse with its shifted phases from 0 to 2π. We show the measured channel parameters, which have been carried out in some lakes in Hanoi. The measured results illustrate that the channel is frequency selective for a Barrow band transmission. The Doppler spectrum can be obtained by taking the Fourier transform of the time correlation of the measured channel transfer function. We have shown that, the theoretical maximum Doppler frequency fits well to that one obtained from measurement results.
Źródło:
Archives of Acoustics; 2019, 44, 2; 375-383
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Przestrzenna i czasowa zmienność stężenia azotanów w płytkich wodach gruntowych w miejscu lokalizacji polowej pryzmy obornika
Spatial and temporal variability of nitrates concentration in shallow groundwater at the field location of the manure heap
Autorzy:
Pietrzak, S.
Rossa, L.
Marcinkowski, T.
Wojcieszak, Ł.
Powiązania:
https://bibliotekanauki.pl/articles/401579.pdf
Data publikacji:
2018
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
azotany
wody gruntowe
polowa pryzma obornika
nitrates
shallow groundwater
field manure heap
Opis:
Płytkie wody podziemne są szczególnie podatne na zanieczyszczenie azotanami pochodzenia rolniczego. W pracy podjęto próbę rozpoznania kierunku przestrzennych i czasowych zmian stężenia azotanów w płytkich wodach gruntowych, zalegających pod warstwą piaszczystej gleby, w miejscu okresowego składowiska obornika i w jego najbliższym otoczeniu. Badania przeprowadzono w latach 2009–2015 na terenie gospodarstwa rolnego ukierunkowanego na produkcję mleka, położonego w północno-zachodniej części środkowego basenu Biebrzy, w województwie podlaskim. Stanowisko badawcze zlokalizowano na skraju pola, na którym corocznie uprawiano kukurydzę i gdzie na przełomie lat 2010/2011 i 2014/2015 okresowo składowano obornik. Próbki wód gruntowych pobierano korzystając z 7 studzienek kontrolno-pomiarowych, w odstępach miesięcznych, 4-8 razy w roku. Uzyskane zbiory wyników zawartości azotanów poddano analizie statystycznej z wykorzystaniem analizy wariancji z testem Kruskala-Wallisa. Przeprowadzono również analizę korelacji stężenia azotu azotanowego w wodzie z różnych punktów badawczych oraz analizę jego regresji w kolejnych latach badań. Średnie, roczne stężenie azotu azotanowego w próbkach wód gruntowych pobieranych z poszczególnych studzienek kształtowało się szerokim zakresie wartości od 1,1 do 101,8 mg N-NO3∙dm–3. W zdecydowanej większości przypadków (86%) wielokrotnie przekraczało ono graniczną wartość dla III klasy jakości wód podziemnych czyli 11,3 mg N-NO3∙dm–3. Zatem badane wody należy zaliczyć do wód zanieczyszczonych bądź zagrożonych zanieczyszczeniem. Ponad to w ujęciu przestrzennym i czasowym, średnie, roczne zawartości azotanów w badanych próbach wód gruntowych, pobieranych ze studzienek zainstalowanych na terenie stanowiska badawczego charakteryzowały się znacznym zróżnicowanym przestrzennym, miały odmienne nasilenie jak też kierunki zmian w czasie, w niewielkim stopniu były ze sobą skorelowanie.
Shallow groundwater is particularly susceptible to contamination by nitrates from agricultural sources. The paper attempts to recognize the direction of spatial and temporal changes in the concentration of nitrates in shallow groundwater, lying under a layer of sandy soil, in the place of a temporary manure storage place and in its immediate vicinity. The study was conducted in the years 2009–2015 on farm focused on milk production, located in the north-western part of the central basin of Biebrza, in Podlaskie voivodeship . The research stand was located at the edge of the field where maize was grown every year and where manure was periodically stored at the turn of 2010/2011 and 2014/2015. Groundwater samples were collected using 7 control and measurement wells, on a monthly basis, 4-8 times a year. The obtained results of nitrates content were subjected to statistical analysis using the analysis of variance with the Kruskal-Wallis test. The analysis of correlation of nitrate nitrogen concentration in water from various research points and analysis of its regression in subsequent years of research was also performed. The average annual concentration of nitrate nitrogen in groundwater samples collected from individual wells was in the wide range from 1.1 to 101.8 mg NO3∙dm–3. In the vast majority of cases (86%) it repeatedly exceeded the limit value for the third class of groundwater quality, or 11.3 mg N-NO3∙dm–3. Thus, the tested water should be classified as polluted or at risk of contamination. In addition, in spatial and temporal terms, the average annual nitrates content in the tested groundwater samples collected from wells installed on the research site was characterized by a significant different spatial, has a different intensity as well as directions of changes in time, to a small extent correlated with each other.
Źródło:
Inżynieria Ekologiczna; 2018, 19, 5; 75-82
2081-139X
2392-0629
Pojawia się w:
Inżynieria Ekologiczna
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Miękka podkładka pod centralną częścią fundamentu bezpośredniego elektrowni wiatrowej
Soft comprehesive layer under the central part of wind turbine shallow foundations
Autorzy:
Dołżyk, K.
Szypcio, Z.
Chmielewska, I.
Powiązania:
https://bibliotekanauki.pl/articles/402709.pdf
Data publikacji:
2013
Wydawca:
Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Tematy:
elektrownie wiatrowe
fundamenty bezpośrednie
obciążenie wiatrem
wind turbines
shallow foundations
wind load
Opis:
W pracy omówiono niektóre problemy fundamentowania bezpośredniego elektrowni wiatrowych. Elektrownie wiatrowe są bardzo specyficznymi budowlami. Główne siły przekazywane na fundament są wywołane działaniem wiatru. Wiatr wieje o różnej sile z różnych kierunków, zatem fundament musi mieć dużą sztywność. Zwykle fundamentem jest płyta kołowa o różnej grubości i średnicy kilkunastu metrów. W pracy wykazano, że celowym jest wykonanie miękkiej podkładki w centralnej części fundamentu, znacząco eliminującej różnice osiadań nieodwracalnych części środkowej i brzegów fundamentu. Miękka podkładka o promieniu mniejszym niż 0,3 promienia fundamentu nie zmniejsza jego nośności i sztywności na obrót.
The paper discusses some problems relating to shallow foundations of wind turbines. Wind turbines are very specific buildings. Main actions transmitted onto foundations are produced by wind. The power of wind varies as it blows from different directions and at a different speed so the foundation must be very stiff. Usually, the foundation is a circular plate of different thickness and a diameter of more than ten meters. It has been shown in this study that it is reasonable to build soft compressive material under the central part of the foundation. The compressive material significantly eliminates irreversible settlement differences of the center and edge of the foundation. The soft compressive material which radius is smaller than 0.3 of foundation radius does not reduce its bearing capacity and rotational stiffness.
Źródło:
Budownictwo i Inżynieria Środowiska; 2013, 4, 3; 193-197
2081-3279
Pojawia się w:
Budownictwo i Inżynieria Środowiska
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mathematical model of forecasting the formation of sinkhole using Salustowicz’s theory
Model matematyczny prognozowania zapadlisk przy wykorzystaniu teorii sklepienia ciśnień Sałustowicza
Autorzy:
Strzałkowski, P.
Powiązania:
https://bibliotekanauki.pl/articles/219816.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
rock mechanics
shallow caverns
predicting sinkholes
mechanika górotworu
prognozowanie zapadlisk
płytkie pustki
Opis:
In area affected by old, shallow extraction in some cases sinkholes are formed, causing security issues in urbanized areas. Problem of working out deterministic forecast of this threat seems to be important and up-to-date. Mathematical model presented in this work let us predict the possibility of sinkhole formation. That prediction is essential for analyzing possibility of investments in such areas. Basing on presented work, it is also possible to determine dimensions of sinkhole. Considerations are based on known from literature Sałustowicz’s theory, which is utilises Huber’s solution of equation describing the stress state around elliptic void made in flat plate.
Początki eksploatacji górniczej na Górnym Śląsku sięgają XVIII stulecia. Dawna eksploatacja prowadzona na głębokościach nie przekraczających 80 m, do dziś generuje zagrożenia bezpieczeństwa powszechnego z uwagi na możliwość wystąpienia zapadlisk. Jak to wynika z pracy (Chudek i in., 2013), obszary pod którymi prowadzono w minionych latach płytką eksploatację zajmują znaczną powierzchnię śląskich miast, które w dalszym ciągu się rozbudowują. Dlatego problem występowania zapadlisk należy w dalszym ciągu uznać za ważny i aktualny. Duża liczba zapadlisk, ze zrozumiałych względów, jest wynikiem utraty stateczności płytkich wyrobisk korytarzowych. Istniejące metody prognozowania zapadlisk pozwalają głównie określać prawdopodobieństwo wystąpienia zapadliska. Jeśli wartość prawdopodobieństwa wystąpienia zapadliska jest większa od 0, wówczas należy się liczyć z zagrożeniem bezpieczeństwa terenu i co istotniejsze ludności. Taki sposób prognozowania wystąpienia zapadlisk nie daje jednoznacznej odpowiedzi na pytanie, czy teren objęty analizą jest rzeczywiście zagrożony. Dlatego istotnym jest stworzenie możliwości deterministycznego prognozowania tego typu deformacji. W tym kierunku zmierza propozycja autora pracy, w której wykorzystano teorię sklepienia ciśnień (Sałustowicz, 1956). Teoria ta znakomicie nadaje się do tego celu, gdyż jako jedyna z wielu w tym zakresie pozwala określić, czy pustka związana z wyrobiskiem znajduje się w stanie stateczności. Znane są bowiem przypadki, gdy płytkie wyrobiska górnicze, bez obudowy przez wiele lat pozostają w stanie nienaruszonym. W ramach pracy dokonano szczegółowych obliczeń pola strefy odprężonej nad wyrobiskiem, bez stosowania uproszczeń przyjętych przez autora metody. Stosując podobne założenia jak w innych, znanych z literatury rozwiązaniach, podano warunki, mówiące o tym kiedy gruzowisko skalne zapełni szczelnie pustkę, bez powstania pustki wtórnej, a kiedy pustka wtórna powstanie. Zależy to od wymiarów i głębokości lokalizacji pustki oraz własności górotworu nad pustką. Warunkiem wystąpienia zapadliska jest aby strefa odprężona, związana z pustką pierwotną lub wtórną osiągnęła wysokość, przy której obejmować będzie nadkład, zbudowany ze skał luźnych. W dalszej kolejności zaproponowano wzory umożliwiające określenie wymiarów zapadlisk. Wyróżniono przy tym dwa przypadki: gdy strop pustki osiąga spąg nadkładu – wzór (15), gdy strefa odprężona obejmuje swym zasięgiem luźne skały nadkładu – wzór (19). Dalszym etapem badań prowadzonych przez autora jest sformułowanie warunków, pozwalających stwierdzić, kiedy eksploatacja górnicza prowadzona pod pustką może wywołać jej samopodsadzenie, a w konsekwencji spowodować powstanie zapadliska na powierzchni. Prowadzone są również prace związane z utworzeniem oprogramowania komputerowego, wykorzystującego podane wzory i z weryfikacją rozwiązania w oparciu o przypadki znane z praktyki górniczej.
Źródło:
Archives of Mining Sciences; 2015, 60, 1; 63-71
0860-7001
Pojawia się w:
Archives of Mining Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ekologia głęboka a edukacja. W poszukiwaniu nowego paradygmatu
Deep Ecology and Education: Searching for a New Reference Point
Autorzy:
Nawrocki, Radosław
Powiązania:
https://bibliotekanauki.pl/articles/2149062.pdf
Data publikacji:
2019
Wydawca:
Uniwersytet w Białymstoku. Wydział Pedagogiki i Psychologii
Tematy:
ekologia głęboka
płytka ekologia
antropocentryzm
Arne Naess
deep ecology
shallow ecology
anthropocentrism
Opis:
Celem niniejszego tekstu jest przedstawienie podstawowych założeń tzw. głębokiej ekologii. Twierdzę, że skrupulatne i uważne wyciągnięcie wniosków z tej koncepcji może stać się ważnym i inspirującym punktem odniesienia dla edukacji. Chodzi tu zarówno o dyskursy pedagogiczne, jak i praktykę edukacyjną. Głęboka ekologia zawiera w sobie odmienną od najbardziej utrwalonej w kulturze zachodniej koncepcję człowieka oraz jego miejsca w świecie. Odmienność ta związana jest z definiowaniem człowieka i jego relacji ze światem, powinnościami wobec środowiska, sposobem myślenia, strategią budowania tożsamości. To istotnie wpływa na koncepcję edukacji, jaką przyjmujemy.
The purpose of this text is to present the basic assumptions of deep ecology. In my view, meticulous and careful drawing of conclusions from this concept can become an important and inspiring reference point for education, both in terms of pedagogical discourses and educational practice. Deep ecology involves a concept of human and their place in the world different from the majority of concepts well-established in the Western culture. This difference is related to the definition of human and their relationship with the world, obligations towards the environment, way of thinking, and strategy of building identity. This significantly affects the concept of education that we adopt.
Źródło:
Parezja. Czasopismo Forum Młodych Pedagogów przy Komitecie Nauk Pedagogicznych PAN; 2019, 1(11); 30-42
2353-7914
Pojawia się w:
Parezja. Czasopismo Forum Młodych Pedagogów przy Komitecie Nauk Pedagogicznych PAN
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ranking of the utility of selected geostatistical interpolation methods in conditions of highly skewed seismic data distributions: a case study of the Baltic Basin (Poland)
Ranking przydatności wybranych metod interpolacji geostatystycznej w warunkach silnie skośnych rozkładów danych sejsmicznych: studium przypadku Basenu Bałtyckiego (Polska)
Autorzy:
Sowińska-Botor, Justyna
Mastej, Wojciech
Maćkowski, Tomasz
Powiązania:
https://bibliotekanauki.pl/articles/27311659.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Instytut Gospodarki Surowcami Mineralnymi i Energią PAN
Tematy:
seismic data
data processing
shallow subsurface
dane sejsmiczne
przetwarzanie danych
strefa przypowierzchniowa
Opis:
The suitability of several low-labor geostatistical procedures in the interpolation of highly positively skewed seismic data distributions was tested in the Baltic Basin. These procedures were a combination of various estimators of the model of spatial variation (theoretical variogram) and kriging techniques, together with the initial data transformation to normal distribution or lack thereof. This transformation consisted of logarithmization or normalization using the anamorphosis technique. Two variations of the theoretical variogram estimator were used: the commonly used classical Matheron estimator and the inverse covariance estimator (InvCov), which is robust with regard to non-ergodic data. It was expected that the latter would also be resistant to strongly skewed data distributions. The kriging techniques used included the commonly used ordinary kriging, simple kriging useful for standardized data and the non-linear median indicator kriging technique. It was confirmed that normalization (anamorphosis) is the most useful and less laborious geostatistical procedure of those suitable for such data, which results in a standardized normal distribution. The second, not obvious statement for highly skewed data distributions suggests that the non-ergodic inverted covariance (InvCov) estimator of variogram has an advantage over the Matheron’s estimator. It gives a better assessment of the C0 (nugget effect) and C (sill) parameters of the spatial variability model. Such a conclusion can be drawn from the fact that the higher the estimation of the relative nugget effect L = C0/(C0 + C) using the InvCov estimator, the weaker the correlation between the kriging estimates and the observed values. The values of the coefficient L estimates obtained by using the Matheron’s estimator do not meet this expectation.
W ramach studium przypadku w rejonie basenu bałtyckiego przetestowano przydatność kilku mało pracochłonnych procedur geostatystycznych do interpolacji silnie skośnych rozkładów danych sejsmicznych. Były one kombinacją różnych estymatorów modelu zmienności przestrzennej (wariogramu teoretycznego) i technik krigingu, wraz ze wstępną transformacją danych do rozkładu normalnego lub jej brakiem. Transformacja ta polegała na logarytmowaniu bądź na normalizacji z użyciem techniki anamorfozy. Zastosowano dwie odmiany estymatora wariogramu teoretycznego: powszechnie stosowany klasyczny estymator Matherona oraz estymator odwróconej kowariancji (InvCov) odporny na dane nieergodyczne. Spodziewano się, że ten drugi okaże się również odporny na silnie skośne rozkłady dane. Wśród zastosowanych technik krigingu znalazł się powszechnie stosowany kriging zwyczajny, kriging prosty użyteczny dla danych zestandaryzowanych i nieliniowa technika krigingu wskaźnikowego. Najbardziej użyteczną i mało pracochłonną procedurą geostatystyczną, nadającą się do zastosowania w przypadku takich danych, okazała się normalizacja (anamorfoza), w efekcie której uzyskuje się rozkład normalny standaryzowany. Drugim, nieoczywistym wnioskiem dla silnie skośnych rozkładów danych, jest sugestia, iż estymator InvCov ma przewagę nad estymatorem Matherona, ponieważ pozwala na bardziej realistyczną ocenę parametrów C0 (efektu samorodka) i C (wariancji progowej) modelu zmienności przestrzennej. Taki wniosek można wyciągnąć z faktu, że im wyższa wartość relatywnego efektu samorodków L = C0/(C0 + C) obliczona za pomocą estymatora InvCov, tym słabsza korelacja między wartościami obliczonymi a danymi. Wartości współczynnika L obliczone za pomocą estymatora Matherona nie posiadają tej właściwości.
Źródło:
Gospodarka Surowcami Mineralnymi; 2023, 39, 3; 149--172
0860-0953
Pojawia się w:
Gospodarka Surowcami Mineralnymi
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Two-dimensional Numerical Model of Heat Exchange in the Soil Massif During the Operation of a Shallow Horizontal Soil Heat Exchanger
Autorzy:
Basok, Boris
Pavlenko, Anatoliy
Nedbailo, Oleksandr
Bozhko, Ihor
Moroz, Maryna
Powiązania:
https://bibliotekanauki.pl/articles/30145705.pdf
Data publikacji:
2023
Wydawca:
Politechnika Koszalińska. Wydawnictwo Uczelniane
Tematy:
shallow horizontal soil heat exchanger
heat flux
numerical modelling
renewable energy sources
Opis:
The current article uses a two-dimensional numerical model to represent the results of theoretical studies of the heat exchange in the soil massif during the operation of a shallow horizontal soil heat exchanger. The analysis of literature sources showed that one of the important conditions for the effective operation of a shallow-soil heat exchange is its rational design parameters, such as the total length of the pipeline, the diameter of the pipe, the distance between the axis of the adjacent pipes, the depth of the heat exchanger placement, etc. A two-dimensional heat exchange model in the soil mass was developed, which made it possible to investigate the operation of a shallow horizontal soil heat exchanger. It was found that the step between the axis of the adjacent pipes of the multi-loop heat exchanger, which is 0.95 m, is optimal when creating a shallow horizontal soil heat exchanger in the soil conditions of Kyiv.
Źródło:
Rocznik Ochrona Środowiska; 2023, 25; 274-281
1506-218X
Pojawia się w:
Rocznik Ochrona Środowiska
Dostawca treści:
Biblioteka Nauki
Artykuł
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