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Wyszukujesz frazę "energy decay" wg kryterium: Temat


Wyświetlanie 1-13 z 13
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:
Uniform energy decay rates of hyperbolic equations with nonlinear boundary and interior dissipation
Autorzy:
Lasiecka, I.
Triggiani, R.
Powiązania:
https://bibliotekanauki.pl/articles/970305.pdf
Data publikacji:
2008
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
non-linear hyperbolic equations
uniform energy decay rates
Opis:
We consider the problem of uniform stabilization of nonlinear hyperbolic equations, epitomized by the following three canonical dynamics: (1) the wave equation in the natural state space L2(Ω) x H^-1(Ω), under nonlinear (and non-local) boundary dissipation in the Dirichlet B.C., as well as nonlinear internal damping; (2) a corresponding Kirchhoff equation in the natural state space [wzór), under nonlinear boundary dissipation in the 'moment' B.C. as well as nonlinear internal damping; (3) the system of dynamic elasticity corresponding to (1). All three dynamics possess a strong, hard-to-show 'boundary → boundary' regularity property, which was proved, also by invoking a micro-local argument, in Lasiecka and Triggiani (2004, 2008). This is by no means a general property of hyperbolic or hyperbolic-like dynamics (Lasiecka and Triggiani, 2003, 2008). The present paper, as a continuation of Lasiecka and Triggiani (2008), seeks to take advantage of this strong regularity property in the case of those PDE dynamics where it holds true. Thus, under the above boundary → boundary regularity, as well as exact controllability of the corresponding linear model, uniform stabilization of nonlinear models is obtained under minimal nonlinear assumptions, provided that a corresponding unique continuation property holds true. The treatment of the present paper is cast in the abstract setting (Lasiecka, 1989, 2001; Lasiecka and Triggiani, 2000, Ch. 7, 2003, 2008), which is proper for these hyperbolic dynamics and recovers the results of Lasiecka and Triggiani (2003, 2008) in the absence of the nonlinear interior damping, in particular in the linear case.
Źródło:
Control and Cybernetics; 2008, 37, 4; 935-969
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Existence and decay of finite energy solutions for semilinear dissipative wave equations in time-dependent domains
Autorzy:
Nakao, Mitsuhiro
Powiązania:
https://bibliotekanauki.pl/articles/1397374.pdf
Data publikacji:
2021
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
energy decay
global existence
semilinear wave equation
noncylindrical domains
Opis:
We consider the initial-boundary value problem for semilinear dissipative wave equations in noncylindrical domain $\cup_{0 \leq t \leq \infty} \Omega(t) \times \{t\} \subset \mathbb{R}^N \times \mathbb{R}$. We are interested in finite energy solution. We derive an exponential decay of the energy in the case Ω(t) is bounded in $\mathbb{R}^N$ and the estimate $\int_0^\infty E(t)dt \leq C(E(0), ||u(0)||) < \infty $ in the case Ω (t) is unbounded. Existence and uniqueness of finite energy solution are also proved.
Źródło:
Opuscula Mathematica; 2020, 40, 6; 725-736
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Global solutions to the initial-boundary value problem for the quasilinear viscoelastic equation with a derivative nonlinearity
Autorzy:
Nakao, M.
Powiązania:
https://bibliotekanauki.pl/articles/255382.pdf
Data publikacji:
2014
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
global solutions
energy decay
quasilinear wave equation
Kelvin-Voigt dissipation
derivative nonlinearity
Opis:
We prove the existence and uniqueness of a global decaying solution to the initial boundary value problem for the quasilinear wave equation with Kelvin-Voigt dissipation and a derivative nonlinearity. To derive the required estimates of the solutions we employ a ‘loan’ method and use a difference inequality on the energy.
Źródło:
Opuscula Mathematica; 2014, 34, 3; 569-590
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Synthesis of heaviest nuclei and heaviest chemical elements
Autorzy:
Sobiczewski, A.
Powiązania:
https://bibliotekanauki.pl/articles/146684.pdf
Data publikacji:
2011
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
heaviest nuclei
heaviest chemical elements
nuclear reactions
alfa-decay energy
alfa-decay half-life
alfa-decay genetic chains
Opis:
Studies of the heaviest nuclei and heaviest chemical elements are shortly described. Methods of synthesis and identification of these nuclei are discussed. Some details of the studies are illustrated on the example of the nucleus 277Cn, the isotope of the element 112 (copernicium) the discovery of which has been recently approved by IUPAC. General results of the research on superheavy nuclei (atomic number Z = 104–118), synthesized within the period from 1969 (discovery of rutherfordium, Z = 104) up to the present are outlined.
Źródło:
Nukleonika; 2011, 56, 3; 212-216
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of excitation migration on the decay of excited states via electron transfer to acceptors
Autorzy:
Gutman, M.
Hilczer, M.
Tachiya, M.
Powiązania:
https://bibliotekanauki.pl/articles/147856.pdf
Data publikacji:
2005
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
electron transfer
energy migration
simulation
fluorescence decay
polymer matrix
Opis:
Simulation of fluorescence quenching due to electron transfer from a photoexcited donor to an acceptor, in a rigid matrix has been performed. The model assumes competition between processes of the electron transfer and the resonant excitation energy transfer among donors. Electron and energy transfers are described in terms of the Marcus and the Förster theories, respectively. Dependence of the fluorescence quenching on the donor concentration and on the parameters of the Marcus and Förster equations has been investigated at a fixed acceptor concentration. Fluorescence decay curves calculated for various concentrations of donors have been compared with experimental decays.
Źródło:
Nukleonika; 2005, 50,suppl.2; 39-43
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Transient stability analysis and control of power systems with considering flux decay by energy function approach
Autorzy:
Lu, D.
Zhang, X.
Powiązania:
https://bibliotekanauki.pl/articles/201016.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
transient stability
dynamic performance
flux decay
structure preserving models
energy function
Opis:
In this paper, transient stability of power systems with structure preserving models is considered. A Hamiltonian function which can be regarded as a Lyapunov function for the system is proposed. Based on this, the influence of flux decay dynamics, especially during a fault, on transient stability is analyzed. With the increase of load power, the variation of stability boundary in the rotor angle/Eq plane is shown. The Energy-based excitation control, aiming at injecting additional damping into the post-fault system may reduce the critical clearing time (CCT). This can be demonstrated by the comparison of different flux decay dynamics in the fault-on condition, and the reason is illustrated by the relationship between rotor angle/Eq and the stability boundary. An improved control strategy is proposed and applied to increase the CCT. Simulation results verify that improvement is obtained both in transient stability and dynamic performance.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2012, 60, 1; 3-8
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evaluation of the Energy Capacity of the Controlled Landfill from Mohamedia Benslimane by Three Theoretical Methods – Land Gem, IPCC, and TNO
Autorzy:
Oukili, Ahlam Idrissi
Chhiba, Mostafa
Powiązania:
https://bibliotekanauki.pl/articles/2202375.pdf
Data publikacji:
2023
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
controlled landfill
municipal solid waste
biogas
first order decay model
electrical energy
Opis:
The objective of this study was to estimate the content of methane produced and generated by the anaerobic biodegradation of the main organic fraction of municipal solid waste from the controlled landfill of Mohammedia-Benslimane (Morocco) by three theoretical models, based on the first order decay equation: LandGEM, IPCC and TNO. To carry out this study, the quantities of solid waste buried in this landfill since its inauguration in 2012 were used and the composition of the biogas in-situ in 2020 and 2021was determined. The quantities of waste that will be buried in this landfill from 2022 to 2032 were estimated by projection.The results of the analysis of the biogas generated in this controlled landfill in 2020–2021 indicate that it is composed of 59.59% CH4, 38.9% CO2, and 0.14% O2. This result indicates that the waste is in a stable methanogenesis phase. The results obtained by using the three methodologies show that the total volume of CH4 generated during the period 2012–2021 was 32.59 Mm3 according to the IPCC model, 20.95 Mm3 according to the LandGEM model and 20.96 Mm3 according to the TNO model. The total volume of CH4 that will be produced during the period 2022–2032 has been projected to 107.48 Mm3 by the IPCC model, to 76.84 Mm3 by the LandGEM model, while the total volume of CH4 projected under the TNO method will be 67.67 Mm3. The maximum methane production will reach a value of 12.07 Mm3, 9.46 Mm3 and 7.82 Mm3 for the IPCC, LandGEM and TNO models, respectively. In 2021, the volume of methane estimated by the three models is higher than that on-site measurement by a factor of 3.5(IPCC), 2.4 (LandGEM) and 2.3 (TNO). The results clearly indicate that the three models over predict methane generations when compared to the on-site generations. According to the LandGEM methodology, the electricity estimated will reach a maximum value of 33 GWh/year in 2032.The efficient use of methane generated by this controlled landfill as a source of electrical energy in the upcoming years can be an option for the sustainable management of waste.
Źródło:
Journal of Ecological Engineering; 2023, 24, 2; 19--30
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Energy Method for Elastic Problems With Non-Homogeneous Boundary Conditions
Autorzy:
Quintanilla, R.
Powiązania:
https://bibliotekanauki.pl/articles/907887.pdf
Data publikacji:
2002
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
matematyka
weighted energy method
decay estimates
Navier equations
non-homogeneous boundary conditions
Opis:
In this paper we propose the weighted energy method as a way to study estimates of solutions of boundary-value problems with non-homogeneous boundary conditions in elasticity. First, we use this method to study spatial decay estimates in two-dimensional elasticity when we consider non-homogeneous boundary conditions on the boundary. Some comments in the case of harmonic vibrations are considered as well. We also extend the arguments to a class of three-dimensional problems in a cylinder. A section is devoted to the study of an ill-posed problem. Some remarks are presented in the last section of the paper.In this paper we propose the weighted energy method as a way to study estimates of solutions of boundary-value problems with non-homogeneous boundary conditions in elasticity. First, we use this method to study spatial decay estimates in two-dimensional elasticity when we consider non-homogeneous boundary conditions on the boundary. Some comments in the case of harmonic vibrations are considered as well. We also extend the arguments to a class of three-dimensional problems in a cylinder. A section is devoted to the study of an ill-posed problem. Some remarks are presented in the last section of the paper.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2002, 12, 1; 91-100
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Some new aspects of femtoscopy at high energy
Autorzy:
Stavinskiy, A.
Mikhailov, K.
Vlassov, A.
Erazmus, B.
Renault, G.
Powiązania:
https://bibliotekanauki.pl/articles/147368.pdf
Data publikacji:
2004
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
residual correlations
strange baryon decay
reference sample
low energy scattering parameters
space-time
Opis:
It was shown within simple model simulations that particles momenta for strange baryon decay are correlated with its parents momenta. It can affect measure correlation function for different particle species.
Źródło:
Nukleonika; 2004, 49,suppl.2; 23-25
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Characterization of some modern scintillators recommended for use on large fusion facilities in γ-ray spectroscopy and tomographic measurements of γ-emission profiles
Autorzy:
Sibczynski, P.
Broslawski, A.
Gojska, A.
Kiptily, V.
Korolczuk, S.
Kwiatkowski, R.
Mianowski, S.
Moszyński, M.
Rzadkiewicz, J.
Swiderski, L.
Szydlowski, A.
Zychor, I.
Powiązania:
https://bibliotekanauki.pl/articles/146137.pdf
Data publikacji:
2017
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
gamma spectrometry
scintillators
decay time
non-proportionality
energy resolution
detection efficiency
fusion plasma
Opis:
LaBr3:Ce,CeBr3 and GAGG:Ce scintillators were investigated and the determined characteristics were compared with those obtained for the well-known and widely used CsI:Tl and NaI:Tl crystals. All the detectors were of the same size of 10 × 10 × 5 mm3. The aim of this test study was to single out scintillation detectors most suitable for γ-ray spectrometry and γ -ray emission radial profile measurements in high-temperature plasma experiments. Decay time, energy resolution, non-proportionality and full energy peak detection efficiency were measured for γ -ray energies up to 1770 keV. Due to their good energy resolution, short decay time and high detection efficiency for MeV gamma rays, LaBr3:Ce and CeBr3 scintillators are proposed as the best candidates for use especially under conditions of high count rates, which are expected in the forthcoming DT experiments.
Źródło:
Nukleonika; 2017, 62, 3; 223-228
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Revised Sound Energy Theory Based on a New Formula for the Reverberation Radius in Rooms with Non-Diffuse Sound Field
Autorzy:
Arau-Puchades, H.
Berardi, U.
Powiązania:
https://bibliotekanauki.pl/articles/177958.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
reverberation radius
critical distance
non-diffuse sound field
sound energy
revised sound decay theory
Opis:
This paper discusses the concept of the reverberation radius, also known as critical distance, in rooms with non-uniformly distributed sound absorption. The reverberation radius is the distance from a sound source at which the direct sound level equals the reflected sound level. The currently used formulas to calculate the reverberation radius have been derived by the classic theories of Sabine or Eyring. However, these theories are only valid in perfectly diffused sound fields; thus, only when the energy density is constant throughout a room. Nevertheless, the generally used formulas for the reverberation radius have been used in any circumstance. Starting from theories for determining the reverberation time in non-diffuse sound fields, this paper firstly proposes a new formula to calculate the reverberation radius in rooms with non-uniformly distributed sound absorption. Then, a comparison between the classic formulas and the new one is performed in some rectangular rooms with non-uniformly distributed sound absorption. Finally, this paper introduces a new interpretation of the reverberation radius in non-diffuse sound fields. According to this interpretation, the time corresponding to the sound to travel a reverberation radius should be assumed as the lower limit of integration of the diffuse sound energy.
Źródło:
Archives of Acoustics; 2015, 40, 1; 33-40
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Interpolated-DFT-Based Fast and Accurate Amplitude and Phase Estimation for the Control of Power
Autorzy:
Borkowski, J.
Kania, D.
Powiązania:
https://bibliotekanauki.pl/articles/221570.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
control of power
grid signal
amplitude and phase estimation
renewable energy
interpolated DFT
maximum decay side-lobes windows
Opis:
Quality of energy produced in renewable energy systems has to be at the high level specified by respective standards and directives. One of the most important factors affecting quality is the estimation accuracy of grid signal parameters. This paper presents a method of a very fast and accurate amplitude and phase grid signal estimation using the Fast Fourier Transform procedure and maximum decay side-lobes windows. The most important features of the method are elimination of the impact associated with the conjugate’s component on the results and its straightforward implementation. Moreover, the measurement time is very short ‒ even far less than one period of the grid signal. The influence of harmonics on the results is reduced by using a bandpass pre-filter. Even using a 40 dB FIR pre-filter for the grid signal with THD ≈ 38%, SNR ≈ 53 dB and a 20‒30% slow decay exponential drift the maximum estimation errors in a real-time DSP system for 512 samples are approximately 1% for the amplitude and approximately 8.5・10‒2 rad for the phase, respectively. The errors are smaller by several orders of magnitude with using more accurate pre-filters.
Źródło:
Metrology and Measurement Systems; 2016, 23, 1; 13-26
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-13 z 13

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