Informacja

Drogi użytkowniku, aplikacja do prawidłowego działania wymaga obsługi JavaScript. Proszę włącz obsługę JavaScript w Twojej przeglądarce.

English (EN)·Polski (PL)·Yкраїнський (UK)
Przejdź do strony domowej biblioteki Centralna Biblioteka Wojskowa Link otwiera się w nowym oknie Logo biblioteki Prolib Integro - strona głównaCentralna Biblioteka Wojskowa

Wyszukujesz frazę "Sawicki, J. M." wg kryterium: Autor

  Lista filtrów
Wyrównaj
Wyświetlanie 1-15 z 60
Tytuł:
Simplified modeliing of heat transfer in groundwater
Autorzy:
Sawicki, J. M.
Powiązania:
https://bibliotekanauki.pl/articles/241126.pdf
Data publikacji:
2001
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
heat transfer
groundwater
modelling
temperature
2D mathematical model
3D equations
2D equations
Opis:
The paper deals with a 2D mathematical model, which describes the groundwater temperature. Such a model is an interesting alternative for 3D equations, which re-quire much more additional information (i.e. shape and characteristics of the area, initial and boundary conditions) than 2D equations. In the first part of the paper the equations of energy conservation for two main versions of a 2D model (i.e. for a confined and for an unconfined area) were derived. Special attention was paid to two kinds of heat-transfer processes, viz. micro-dispersion, caused by pore-space averaging of the temperature and velocity, and macro-dispersion, due to averaging along the water-layer depth. The analysis of the thermal conditions in the region of the Kozienice electric-power-plant was presented, as an example of the model application.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2001, 48, 4; 85-102
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Transversal pressure effect in circulative separators
Autorzy:
Sawicki, J. M.
Powiązania:
https://bibliotekanauki.pl/articles/241248.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
centrifugal force
cyclones
rotational separators
sedimentation
wastewater treatment
Opis:
Progressive urban development of the human environment requires new methods of rain water treatment. Recently, there has been a growing interest in the improvement of gravitational suspension separation, and especially in the application of the centrifugal force. This important factor can be induced in two ways; by the circulation of the reservoir containing the fluid (centrifugal separators), or by a tangent supply of this reservoir (circulative separators). In addition to the centrifugal force, another essential transversal force is at work in this case, resulting from the local variability of the pressure. In the literature, this force is derived for centrifuge conditions, but applied also to circulative separators, which is questionable, as in the latter devices velocity and pressure fields are clearly different. The paper is devoted to the determination of the transversal pressure effect in circulative separators. First, a model of tangent and radial velocity profiles is introduced. The radial pressure distribution, calculated on this basis and verified experimentally, leads to the final result, that is, a technical formula describing the force in question.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2012, 59, 1-2; 3-12
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Rational determination of dynamic characteristics of fluid-flow reactors
Autorzy:
Sawicki, J. M.
Powiązania:
https://bibliotekanauki.pl/articles/241307.pdf
Data publikacji:
2005
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
fluid-flow reactors
waste treatment
dispersion
Opis:
A new model for water treatment and waste disposal reactors was developed. The startpoint to this model is a "triangular" approximation in the shape of the real flow-through curve. This approximation is defined by some characteristic points of time, which are strongly related to the characteristic velocities of wastewater. Combination of this simplified function with the kinetic equation of the reaction of the 1st order yields the sequence of the governing equations. Three practical examples show that the proposed "rational" model gives much better results than the traditional plug-flow model.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2005, 52, 3; 177-193
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparison of volume- and surface-detention-time distributions
Autorzy:
Sawicki, J. M.
Powiązania:
https://bibliotekanauki.pl/articles/241384.pdf
Data publikacji:
2002
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Opis:
The main process parameter for flow reactors (and in many cases also storage reservoirs) is the detention time. In technical practice the mean value of this parameter is commonly used. This version of the detention time results from the simplified plug-flow-model, which describes the real course of considered fluid-flow-phenomena only to a low degree. In order to obtain more precise characteristics of the system, one should make use of the so-called extrinsic distribution of detention time. Unfortunately, determination of such a curve for the whole reservoir (volume-detention-time) is rather expensive and time-consuming. Preceding this, a very attractive alternative is given by the surface-detention-time, which is determined for the upper layer of the liquid, close to the free surface. Investigation of the equivalence of both these possibilities is the subject of this paper.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2002, 49, 2; 59-70
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hydraulic Loss Coefficients in 1D Flows
Autorzy:
Sawicki, J. M.
Powiązania:
https://bibliotekanauki.pl/articles/241418.pdf
Data publikacji:
2007
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
hydraulic loss
closed-conduits flows
water hammer
open channel flow
Opis:
Determination of hydraulic losses is a very important problem, both from the cognitive and practical points of view. For the uniform and steady fluid streams these losses are described by the well known algebraic expressions, containing some experimental coefficients. In technical practice it is commonly assumed, that these coefficients can be applied also for more complex kinds of flow (non-uniform and even unsteady). However, the problem analysis shows that the proper level of conformity between the results of calculations and measurements can be obtained only after a considerable enlargement of the loss coefficient. Investigation of available characteristics of non-uniform and unsteady 1D velocity fields, presented in this article, leads to the conclusion that this enlargement is physically justified and in some cases it is possible to determine correction factors, which enable recalculation of "basic" coefficients into their new values, suitable for more complex models of 1D flows.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2007, 54, 2; 95-116
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental Determination of Limit Adhesive Shear Stress between Solid Wall and Liquid
Autorzy:
Sawicki, J. M.
Powiązania:
https://bibliotekanauki.pl/articles/241430.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
hydromechanics
slip boundary conditions
adhesion
Opis:
The slip boundary condition can be a very useful relation when some specific problems of hydromechanics are considered. According to the classical form of this condition, the slip of a fluid with respect to the solid wall should occur even at a very low velocity of motion. However, both theoretical analysis and certain empirical data suggest that there must be a limit value of the wall shear stress, below which the slip does not occur. According to the simplified balance of adhesive and gravitational forces, a simple experimental method for determining this stress has been proposed and applied in this paper.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2014, 61, 3-4; 175--181
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Stream Division by a Channel Bottom Orifice
Autorzy:
Sawicki, J. M.
Siebert, M.
Powiązania:
https://bibliotekanauki.pl/articles/241250.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
flow regulator
overfall
storm sewer
Opis:
A particularly important application of devices dividing a stream of liquid is in storm water drainage systems. Dividers of rainwater sewage streams have in recent years aroused considerable interest among producers of separators. It is therefore important to develop mathematically simple and, if possible, physically precise methods of sizing such structures. It is all the more important given that there are few such methods in the literature on hydraulics. This work is meant to partially remedy this deficiency by elaborating on the calculation methodology and by verifying it empirically. A circular orifice at the bottom of the supplying channel is technically the simplest type of stream divider (which makes it higly practical and particularly appealing to producers). A procedure for dimensioning the structure under consideration is proposed here. It is formally simple, being meant as a practical designing tool. This proposal has been verified experimentally. The degree of the division of the stream was measured in a laboratory model. The main issues were the stability of the characteristics of the lateral outflow and the possibility of applying the classical equations of hydraulics to size the type of divider considered here. In both cases the results obtained may be regarded as positive. Admittedly, the output of the lateral outflow exceeds the nominal value for greater inflows Qp, but it is at most double the nominal value. From a technical point of view, this may be regarded as a good result, considering the simplicity of the system. The answer to the second issue proved even more satisfactory. It turns out that the formally simple hydraulics relationships provide a technically consistency of theory with measurement results. Thus the designing of objective devices does not require the application of difficult, time-consuming and costly methodology.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2012, 59, 3-4; 155-163
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Model of Pressure Distribution in Vortex Flow Controls
Autorzy:
Mielczarek, S.
Sawicki, J. M.
Powiązania:
https://bibliotekanauki.pl/articles/241160.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
rotational flow
flow control
vortex valve
storm wastewaters
Opis:
Vortex valves belong to the category of hydrodynamic flow controls. They are important and theoretically interesting devices, so complex from hydraulic point of view, that probably for this reason none rational concept of their operation has been proposed so far. In consequence, functioning of vortex valves is described by CFD-methods (computer-aided simulation of technical objects) or by means of simple empirical relations (using discharge coefficient or hydraulic loss coefficient). Such rational model of the considered device is proposed in the paper. It has a simple algebraic form, but is well grounded physically. The basic quantitative relationship, which describes the valve operation, i.e. dependence between the flow discharge and the circumferential pressure head, caused by the rotation, has been verified empirically. Conformity between calculated and measured parameters of the device allows for acceptation of the proposed concept.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2015, 62, 1-2; 41-52
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Determination of Mechanical Energy Loss in Steady Flow by Means of Dissipation Power
Autorzy:
Artichowicz, W.
Sawicki, J. M.
Powiązania:
https://bibliotekanauki.pl/articles/241274.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
energy decay rate
energy loss
Opis:
When systems of simple geometry like pipes or regular channels are considered, the mechanical energy loss of the fluid flow can be expressed by local and longitudinal empirical energy loss coefficients. However, in the case of large spatially distributed objects, there are no simple approaches to this task. In practice, general recommendations addressing different types of objects are used, but they usually provide very coarse estimates of energy loss. In this work, a new methodology for determination of mechanical energy loss in steady flowis proposed. This methodology is based on the observation that the magnitude of the power of energy dissipation in turbulent flow can be determined using the averaged flow velocity and turbulent viscosity coefficient. To highlight this possibility, an analysis of the magnitudes of the power of the main and fluctuating components of turbulent flow is presented. The correctness of the method is verified using an example of laminar and turbulent flows in a circular pipe. The results obtained show clearly that the proposed methodology can be used for mechanical energy loss determination in flow objects. This methodology can be used as a basis for mechanical energy loss determination in different types of flow objects.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2017, 64, 2; 73-85
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Design criterion for hydrodynamic vortex separator
Autorzy:
Gronowska-Szneler, M.A.
Sawicki, J. M.
Powiązania:
https://bibliotekanauki.pl/articles/175226.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
centrifugal force
particle trajectory
sedimentation
suspended particle
vortex separator
Opis:
The process of designing technical objects involves determination of geometrical parameters that characterize a given device. When device operation is described by differential equations, an inverse problem brings difficulties, as geometrical values being sought condition the solution to the problem. Vortex separators, used for removal of suspension from storm wastewater are usually designed by the ‘criterion method’. Firstly, a critical particle is distinguished such that bigger particles are removed from wastewater stream, whereas smaller particles stay in the stream. Next, by comparing values of major forces acting on the critical particle at the most unfavourable point within the separator (usually at outflow cross-section), a force balance is made. The resulting algebraic relation becomes the design criterion.
Źródło:
Transactions of the Institute of Fluid-Flow Machinery; 2017, 135; 3-9
0079-3205
Pojawia się w:
Transactions of the Institute of Fluid-Flow Machinery
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Verification of Baffle Factor for Straight Pipe Flow
Autorzy:
Artichowicz, W.
Łuczkiewicz, A.
Sawicki, J. M.
Powiązania:
https://bibliotekanauki.pl/articles/240988.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
disinfection chamber
baffle factor
pipe flow
Opis:
The baffle factor is a parameter widely used to describe flow system characteristics. This indicator is very important in designing disinfection devices. For example, it is used to convert the plug flowtime to the actual fluid residence time in the flowsystem of interest. Its accurate determination is a complex problem requiring tracer experiments or computational fluid dynamics simulations. Therefore, in practice, it is often taken from tables provided in the literature. The literature sources, however, state that the baffle factor for a flow in a straight pipe is equal to unity, which implies the identity between the pipe flow model and the plug flow model. This assumption is doubtful. The aim of the present work is to verify the baffle factor values assumed for the pipe flow. The merit of this study is the analytical derivation of the expression describing the baffle factor value with respect to flow characteristics. To this purpose, the analytical solution of a one-dimensional advection-diffusion equation with a Heaviside initial condition was used. It was demonstrated that the aforementioned assumption is wrong, as the baffle factor for a straight pipe is significantly less than unity.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2018, 65, 1; 31-39
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Whirling System of Water Exchange in Breeding Pools
Autorzy:
Matej, K.
Pawliczka, I.
Sawicki, J. M.
Wielgat, P.
Zima, P.
Powiązania:
https://bibliotekanauki.pl/articles/241520.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
sea mammal breeding
sealarium
water circulation
breeding pools
Opis:
To create proper living conditions for sea mammals kept in closed systems, one has to make sure that the characteristics of breeding pools, such as their shape, dimensions, the facing of the walls and bottom, as well as the quality and motion of water, resemble as closely as possible the natural environment of the animals. An appropriate system of water exchange plays a very important role here. A complete exchange of water is time-consuming, expensive and troublesome, so it can be performed only periodically and should be supported by a supplementary continuous exchange. This operation improves water quality and can create a proper velocity field in breeding pools. The breeding pools investigated in the present study are located in a sealarium in Hel (Poland), which belongs to the Institute of Oceanography of the Gdansk University. Tracer measurements, carried out in these reservoirs made it possible to evaluate the intensity of continuous water exchange. It was found that this intensity was insufficient (as evidenced by large dead zones in the pools and short detention time), and therefore alterations to the existing system were proposed (i.e. a tangential position of the inlet and a centrally situated outlet). On the basis of a simplified model of circulative water flow, it was shown that the altered hydraulic system can considerably improve the situation.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2016, 63, 4; 253-263
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A comparison of PCR-based markers for the molecular identification of Sphagnum species of the section Acutifolia
Autorzy:
Sawicki, J.
Szczecinska, M.
Powiązania:
https://bibliotekanauki.pl/articles/57748.pdf
Data publikacji:
2011
Wydawca:
Polskie Towarzystwo Botaniczne
Tematy:
Acutifolia
random amplified polymorphic DNA
Sphagnum
genetic similarity
molecular identification
molecular marker
polymerase chain reaction
genetic relationship
species identification
peat moss
chloroplast
nuclear genome
Opis:
RAPDs, ISJs, ISSRs, ITS and katGs were applied to determine genetic relationships between common Sphagnum species of the section Acutifolia. Twenty populations were genotyped using ten ISJ primers, 12 pairs of katG primers, 10 ISSR and 10 RAPD primers, and a restriction analysis of ITS1 and ITS2. ISSR and katG markers revealed the greatest number of species-specific bands. An analysis of ITS1 and ITS2 regions with restriction enzymes also proved to be a highly effective tool for species identification.
Źródło:
Acta Societatis Botanicorum Poloniae; 2011, 80, 3
0001-6977
2083-9480
Pojawia się w:
Acta Societatis Botanicorum Poloniae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Theoretical analysis of model seabed behavior under water wave excitation
Autorzy:
Sawicki, A.
Mierczyński, J.
Smyczyński, M.
Powiązania:
https://bibliotekanauki.pl/articles/178964.pdf
Data publikacji:
2015
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
sea bed
liquefaction
wave-flume experiments
saturated soils
Opis:
Theoretical analysis of the behavior of a model seabed subjected to water wave excitation is presented. The experiments were performed in the wave flume at the Danish Technological University in Lyngby. Such experiments are unique in engineering sciences and therefore provide unique empirical data for testing various models of the seabed. A controversial explanation of the experiments is presented in the literature. The goal of this research was to study pore pressure changes caused by water waves and the subsequent liquefaction of the seabed. The authors of the present contribution offer their own theoretical explanation of the wave flume experiments and discuss errors found in the literature cited. The analysis is based on the classical soil mechanics, including the Biot type approach.
Źródło:
Studia Geotechnica et Mechanica; 2015, 37, 2; 33-37
0137-6365
2083-831X
Pojawia się w:
Studia Geotechnica et Mechanica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Practical Ways to Improve SAIDI and SAIFI Power Supply Reliability Indicators in an MV Grid
Praktyczne sposoby poprawy wskaźników niezawodności zasilania SAIDI i SAIFI w sieci SN
Autorzy:
Janiszewski, P.
Sawicki, J.
Kurpas, J.
Mróz, M.
Powiązania:
https://bibliotekanauki.pl/articles/952901.pdf
Data publikacji:
2018
Wydawca:
ENERGA
Tematy:
SAIDI
SAIFI indicators
power grid operation reliability
automatic control coordination
SAIFI
wskaźnik SAIDI
niezawodność pracy sieci
koordynacja automatyki
Opis:
Based on a mathematical model of an existing MV network and analysis of its failures, remedies to improve SAIDI and SAIFI reliability indicators are proposed. Factors are identified and described that significantly affect electricity supply interruptions’ duration, frequency of their occurrence, and the number of not supplied recipients. A methodology is proposed for a relatively quick location of the failure site, isolation of the damaged grid element, and restoration of the supply of as many recipients as possible, considering the specificity of grids in mountainous areas. By simulation of potential failures based on the deterministic reliability model (DRM), the effectiveness of the adopted solutions is demonstrated in the perspective of a dozen years or so.
Na podstawie modelu matematycznego rzeczywistej sieci SN oraz analizy awarii w niej występujących wskazano środki zaradcze mające na celu poprawę wskaźników niezawodności zasilania SAIDI i SAIFI. Zidentyfikowano i opisano czynniki istotnie wpływające na czas trwania przerw w dostawach energii elektrycznej, częstotliwość ich występowania oraz liczbę odbiorców pozostających wówczas bez napięcia. Zaproponowano metodykę pozwalającą na możliwie szybką lokalizację miejsca wystąpienia awarii, wyizolowanie uszkodzonego elementu sieci oraz przywrócenie napięcia maksymalnej liczbie odbiorców, uwzględniając specyfikę sieci w terenach górzystych. Symulując potencjalne awarie w oparciu o deterministyczny model niezawodnościowy (DMZ), wykazano poprawność przyjętych rozwiązań w kilkunastoletniej perspektywie.
Źródło:
Acta Energetica; 2018, 1; 45-50
2300-3022
Pojawia się w:
Acta Energetica
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 60

Ta witryna wykorzystuje pliki cookies do przechowywania informacji na Twoim komputerze. Pliki cookies stosujemy w celu świadczenia usług na najwyższym poziomie, w tym w sposób dostosowany do indywidualnych potrzeb. Korzystanie z witryny bez zmiany ustawień dotyczących cookies oznacza, że będą one zamieszczane w Twoim komputerze. W każdym momencie możesz dokonać zmiany ustawień dotyczących cookies