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 "boundary" wg kryterium: Temat

  Lista filtrów
Wyrównaj
Wyświetlanie 1-15 z 975
Tytuł:
Influence of viscous-elastic properties of a cylindrical sealing element on its sealing ability
Autorzy:
Abbasov, Elkhan
Rustamova, Kaklik
Darishova, Aynur
Powiązania:
https://bibliotekanauki.pl/articles/2055051.pdf
Data publikacji:
2021
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
contact pressure
sealing element
boundary condition
potential energy
functional
Opis:
The stress-strain state of a sealing element in the form of a hollow cylinder is defined with regard to viscous-elastic properties of its material. Based on linear laws of heredity, an analytical formula allowing one to determine the axial load necessary for tightness of the surface of the sealing element and the cylinder wall depending on its physic-mechanical properties and geometrical dimensions is found. Influence of viscous-elastic properties of the material of the sealing element on its sealing ability is realized based on the hypothesis of elastic analogy. The results of numerical calculations are represented in the form of graphs of the external force necessary for achieving sightless. It is shown that viscous-elastic properties of the sealer material greatly influence its sealing ability. Because of heredity of the sealer material, values of the external forces drop in some cases by about five times.
Źródło:
Journal of Theoretical and Applied Mechanics; 2021, 59, 3; 481--492
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Positive solution of a fractional differential equation with integral boundary conditions
Autorzy:
Abdo, M. S.
Wahash, H. A.
Panchal, S. K.
Powiązania:
https://bibliotekanauki.pl/articles/122788.pdf
Data publikacji:
2018
Wydawca:
Politechnika Częstochowska. Wydawnictwo Politechniki Częstochowskiej
Tematy:
fractional derivative and integral
positive solutions of nonlinear boundary value problems
upper and lower solutions
fixed point theorem
pochodna ułamkowa
twierdzenie o punkcie stałym
twierdzenia o punkcie stałym Schaudera
równania różniczkowe cząstkowe
nieliniowe cząstkowe równanie różniczkowe
zagadnienie brzegowe
Opis:
In this paper, we prove the existence and uniqueness of a positive solution for a boundary value problem of nonlinear fractional differential equations involving a Caputo fractional operator with integral boundary conditions. The technique used to prove our results depends on the upper and lower solution, the Schauder fixed point theorem and the Banach contraction principle. The result of existence obtained through constructing the upper and lower control functions of the nonlinear term without any monotone requirement.
Źródło:
Journal of Applied Mathematics and Computational Mechanics; 2018, 17, 3; 5-15
2299-9965
Pojawia się w:
Journal of Applied Mathematics and Computational Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Approximation of a Solidification Problem
Autorzy:
Aboulaich, R.
Haggouch, I.
Souissi, A.
Powiązania:
https://bibliotekanauki.pl/articles/908072.pdf
Data publikacji:
2001
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
optymalizacja
metoda elementów skończonych
Stefan problem
free boundary
shape optimization
Euler method
finite element method
Opis:
A two-dimensional Stefan problem is usually introduced as a model of solidification, melting or sublimation phenomena. The two-phase Stefan problem has been studied as a direct problem, where the free boundary separating the two regions is eliminated using a variational inequality (Baiocci, 1977; Baiocchi et al., 1973; Rodrigues, 1980; Saguez, 1980; Srunk and Friedman, 1994), the enthalpy function (Ciavaldini, 1972; Lions, 1969; Nochetto et al.., 1991; Saguez, 1980), or a control problem (El Bagdouri, 1987; Peneau, 1995; Saguez, 1980). In the present work, we provide a new formulation leading to a shape optimization problem. For a semidiscretization in time, we consider an Euler scheme. Under some restrictions related to stability conditions, we prove an L^2-rate of convergence of order 1 for the temperature. In the last part, we study the existence of an optimal shape, compute the shape gradient, and suggest a numerical algorithm to approximate the free boundary. The numerical results obtained show that this method is more efficient compared with the others.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2001, 11, 4; 921-955
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Seismic stratigraphic analysis for hydrocarbon exploration in the Beta Field, Coastal Swamp Depobelt, Niger Delta
Autorzy:
Adeleye, Mutiu A.
Yekeen, Kazeem O.
Amidu, Sikiru A.
Powiązania:
https://bibliotekanauki.pl/articles/1841773.pdf
Data publikacji:
2020
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
seismic stratigraphy
system tracts
sequence boundary
depositional sequences
reservoir presence
Nigeria
Opis:
Hydrocarbon exploration analysis from a seismic stratigraphic approach was carried out within the Beta Field, Coastal Swamp Depobelt, Niger Delta, to identify system tracts and sequence boundaries that could be associated with potential hydrocarbon accumulation. 3D seismic volume and data from four wells were analyzed. Depositional sequences, system tracts, sequence boundaries, and candidate maximum flooding surfaces were picked from logs, while reflection patterns and terminations were interpreted from seismic sections. Log shapes from gamma rays in combination with seismic facies analysis were interpreted in order to delineate lithology, depositional environments and depositional sequences. Seismic attributes were extracted and were draped on gridded surfaces from the interpreted seismic horizons. These were integrated with structure maps to obtain structural and stratigraphic trends, and possible presence of reservoir sand. Five depositional sequences and nine seismic facies were identified within the field. The depositional sequences were designated Sequences S1 to S5 based on the depth of the occurrences and stacking patterns. This study reveals a progression from fluvial depositional settings to the shelf. The main reservoirs identified are the sand units of the highstand and lowstand within three depositional sequences (S1, S4 and S5) although interbedded sands within the TST of S4 and S5 are also suspected of being potential reservoirs. The channel sand deposits within the study area are suspected to be hydrocarbon bearing as they occurred within the complex fault trapping system popular in the Niger Delta. The application of seismic stratigraphy, as shown in this study, serves to encourage exploration in the Niger Delta where it could be effectively employed for reducing risk in hydrocarbon exploration.
Źródło:
Geology, Geophysics and Environment; 2020, 46, 4; 259-271
2299-8004
2353-0790
Pojawia się w:
Geology, Geophysics and Environment
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of three-dimensional magnetic field in the interior of ring shaped sector
Trójwymiarowa analiza pola magnetycznego we wnętrzu pierścienia
Autorzy:
Afanasev, A.
Sidorov, N.
Powiązania:
https://bibliotekanauki.pl/articles/159196.pdf
Data publikacji:
2009
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Elektrotechniki
Tematy:
analiza pola magnetycznego
pole magnetyczne
problem brzegowy
równanie Laplace'a
magnetic field analysis
boundary problem
Laplace’s equations
Opis:
The subject of the paper is analytical solution of common boundary value problem for Laplace equation in the interior of sector of torus with rectangular cross-section using Fourier method of separation of variables.
Zaprezentowano rozwiązanie analityczne wyznaczenia wartości brzegowych dla równania Laplace'a we wnętrzu pierścienia. Zastosowano metodę Fouriera z rozdzieleniem zmiennych.
Źródło:
Prace Instytutu Elektrotechniki; 2009, 240; 163-178
0032-6216
Pojawia się w:
Prace Instytutu Elektrotechniki
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Effect of Angle of Attack and Flow Conditions on Turbulent Boundary Layer Noise of Small Wind Turbines
Autorzy:
Afanasieva, N.
Powiązania:
https://bibliotekanauki.pl/articles/177922.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
wind turbine
airfoil self-noise
turbulent boundary layer
flow conditions
angle of attack
Opis:
The article aims to solve the problem of noise optimization of small wind turbines. The detailed analysis concentrates on accurate specification and prediction of the turbulent boundary layer noise spectrum of the blade airfoil. The angles of attack prediction for a horizontal axis wind turbine (HAWT) and the estimation based on literature data for a vertical axis one (VAWT), were conducted, and the influence on the noise spectrum was considered. The 1/3-octave sound pressure levels are obtained by semi-empirical model BPM. Resulting contour plots show a fundamental difference in the spectrum of HAWT and VAWT reflecting the two aerodynamic modes of flow that predefine the airfoil self-noise. Comparing the blade elements with a local radius of 0.875 m in the HAWT and VAWT conditions the predicted sound pressure levels are the 78.5 dB and 89.8 dB respectively. In case of the HAWT with predicted local angle of attack ranging from 2.98º to 4.63º, the acoustic spectrum will vary primarily within broadband frequency band 1.74–20 kHz. For the VAWT with the local angle of attack ranging from 4º to 20º the acoustic spectrum varies within low and broadband frequency bands 2 Hz – 20 kHz.
Źródło:
Archives of Acoustics; 2017, 42, 1; 83-91
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of non-classical boundary conditions on the free vibration response of a cantilever Euler-Bernoulli beams
Autorzy:
Afras, Abderrachid
El Ghoulbzouri, Abdelouafi
Powiązania:
https://bibliotekanauki.pl/articles/2174479.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
Tematy:
free vibration
natural frequency
boundary conditions
DTM
non-dimensional stiffness
drgania swobodne
częstotliwość drgań
warunki brzegowe
Opis:
In this article, the problem of the free vibration behavior of a cantilever Euler-Bernoulli beam with various non-classical boundary conditions, such as rotational, translational spring, and attached mass is investigated. For describing the differential equation of the system. An analytical procedure is proposed firstly, and a numerical method based on the differential transform method DTM is developed in order to validate the obtained results. A parametric study for various degenerate cases is presented with the aim to analyze the influence of rotational stiffness, vertical stiffness, and mass ratio on the free vibration response of the beam, particularly on its modal characteristics. The results show that the non-classical boundary conditions significantly affect the natural frequency and mode shapes of the studied beam system in comparison to the case of a classical boundary conditions such as Simply supported, clamped-clamped, etc. The comparison between the obtained results based on the proposed analytical solution and numerical scheme, and those available in the literature shows an excellent agreement.
Źródło:
Diagnostyka; 2023, 24, 1; art. no. 2023107
1641-6414
2449-5220
Pojawia się w:
Diagnostyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Boundary value problems for n-th order differential inclusions with four-point integral boundary conditions
Autorzy:
Ahmad, B.
Ntouyas, S. K.
Powiązania:
https://bibliotekanauki.pl/articles/255975.pdf
Data publikacji:
2012
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
differential inclusions
four-point integral boundary conditions
existence
nonlinear alternative of Leray Schauder type
fixed-point theorems
Opis:
In this paper, we discuss the existence of solutions for a four-point integral boundary value problem of n-th order differential inclusions involving convex and non-convex multivalued maps. The existence results are obtained by applying the nonlinear alternative of Leray Schauder type and some suitable theorems of fixed point theory.
Źródło:
Opuscula Mathematica; 2012, 32, 2; 205-226
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A study of second order differential inclusions with four-point integral boundary conditions
Autorzy:
Ahmad, Bashir
Ntouyas, Sotiris
Powiązania:
https://bibliotekanauki.pl/articles/729334.pdf
Data publikacji:
2011
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
differential inclusions
four-point integral boundary conditions
existence
nonlinear alternative of Leray Schauder type
fixed point theorems
Opis:
In this paper, we discuss the existence of solutions for a four-point integral boundary value problem of second order differential inclusions involving convex and non-convex multivalued maps. The existence results are obtained by applying the nonlinear alternative of Leray Schauder type and some suitable theorems of fixed point theory.
Źródło:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization; 2011, 31, 2; 137-156
1509-9407
Pojawia się w:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An existence theorem for fractional hybrid differential inclusions of Hadamard type
Autorzy:
Ahmad, Bashir
Ntouyas, Sotiris
Powiązania:
https://bibliotekanauki.pl/articles/729503.pdf
Data publikacji:
2014
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
Hadamard fractional derivative
hybrid differential inclusions
Diriclet boundary conditions
existence
fixed point
Opis:
This paper studies the existence of solutions for fractional hybrid differential inclusions of Hadamard type by using a fixed point theorem due to Dhage. The main result is illustrated with the aid of an example.
Źródło:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization; 2014, 34, 2; 207-218
1509-9407
Pojawia się w:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nonlinear fractional differential inclusions with anti-periodic type integral boundary conditions
Autorzy:
Ahmad, Bashir
Ntouyas, Sotiris
Powiązania:
https://bibliotekanauki.pl/articles/729350.pdf
Data publikacji:
2012
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
fractional differential inclusions
anti-periodic
integral boundary conditions
existence
fixed point theorems
Opis:
This article studies a boundary value problem of nonlinear fractional differential inclusions with anti-periodic type integral boundary conditions. Some existence results are obtained via fixed point theorems. The cases of convex-valued and nonconvex-valued right hand sides are considered. Several new results appear as a special case of the results of this paper.
Źródło:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization; 2012, 32, 1; 45-62
1509-9407
Pojawia się w:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Chemically reacting ionized radiative fluid flow through an impulsively started vertical plate with induced magnetic field
Autorzy:
Ahmed, T.
Alam, M. M.
Ferdows, M.
Tzirtzilakis, E. E.
Powiązania:
https://bibliotekanauki.pl/articles/264343.pdf
Data publikacji:
2019
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
warstwa graniczna
promieniowanie
pole magnetyczne
gaz zjonizowany
boundary layer
radiative flow
strong magnetic field
ionized gas
flow field
Opis:
Numerical studies have been performed to examine the chemically reacting ionized fluid flow through a vertical plate with induced magnetic field. This study is performed for the cooling problem. To obtain the nondimensional non-similar momentum, the induced magnetic field, energy and concentration equations, usual nondimensional variables have been used. The numerical solutions for the velocity fields, induced magnetic fields, temperature distribution as well as concentration distribution are obtained for associated parameters using the explicit finite difference method. The local and average shear stresses, current densities, Nusselt number as well as the Sherwood number are also investigated. The obtained results are discussed with the help of graphs to observe effects of various parameters entering into the problem. Also the stability conditions of the explicit finite difference method are analyzed. Finally, a qualitative comparison of the present results with previously published results has been made.
Źródło:
International Journal of Applied Mechanics and Engineering; 2019, 24, 1; 5-36
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the applicability of integrated UAV photogrammetry and automatic feature extraction for cadastral mapping
Autorzy:
Ajayi, Oluibukun Gbenga
Oruma, Emmanuel
Powiązania:
https://bibliotekanauki.pl/articles/43852813.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
zarządzanie gruntami
segmentacja obrazu
mapowanie
land management
remote sensing applications
image segmentation
automatic boundary extraction
UAV mapping
Opis:
The applicability of integratedUnmannedAerialVehicle (UAV)-photogrammetry and automatic feature extraction for cadastral or property mapping was investigated in this research paper. Multi-resolution segmentation (MRS) algorithm was implemented on UAVgenerated orthomosaic for mapping and the findings were compared with the result obtained from conventional ground survey technique using Hi-Target Differential Global Positioning System (DGPS) receivers. The overlapping image pairs acquired with the aid of a DJI Mavic air quadcopter were processed into an orthomosaic using Agisoft metashape software while MRS algorithm was implemented for the automatic extraction of visible land boundaries and building footprints at different Scale Parameter (SPs) in eCognition developer software. The obtained result shows that the performance of MRS improves with an increase in SP, with optimal results obtained when the SP was set at 1000 (with completeness, correctness, and overall accuracy of 92%, 95%, and 88%, respectively) for the extraction of the building footprints. Apart from the conducted cost and time analysis which shows that the integrated approach is 2.5 times faster and 9 times cheaper than the conventional DGPS approach, the automatically extracted boundaries and area of land parcels were also compared with the survey plans produced using the ground survey approach (DGPS) and the result shows that about 99% of the automatically extracted spatial information of the properties fall within the range of acceptable accuracy. The obtained results proved that the integration of UAVphotogrammetry and automatic feature extraction is applicable in cadastral mapping and that it offers significant advantages in terms of project time and cost.
Źródło:
Advances in Geodesy and Geoinformation; 2022, 71, 1; art. no. e19, 2022
2720-7242
Pojawia się w:
Advances in Geodesy and Geoinformation
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of viscous dissipation and wall conduction on steady mixed convection Couette flow of heat generating / absorbing fluid
Autorzy:
Ajibade, A. O.
Umar, A. M.
Powiązania:
https://bibliotekanauki.pl/articles/264671.pdf
Data publikacji:
2019
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
strumień masy
kanał pionowy
konwekcja mieszana
mixed convection
viscous dissipation
vertical channel
boundary thickness
mass constant flux
Opis:
This article theoretically investigated mixed convection flow of heat generating/absorbing fluid in the presence of viscous dissipation and wall conduction effects. The flow is considered to be steady in a vertical channel with some boundary thickness. One of the plates is heated while the other is kept at ambient temperature. The governing flow equations were solved analytically using Homotopy Perturbation Method (HPM). The influences of the governing parameters were captured in graphs, tables and a table was constructed for validation of the work. It is worthwhile to stress that, both the velocity and temperature profiles decrease near the heated plate with an increase in boundary thickness (d) while the reverse cases were observed toward the cold plate. The velocity profile increases near the heated plate with increase in mixed convection parameter (Gre) and decreases towards the cold plate. Rate of heat transfer has been observed to decrease with increase in boundary plate thickness (d) while the critical value of (Gre) increases with growing boundary plate thickness. The study therefore established the importance of boundary plate thickness in mixed convection investigation.
Źródło:
International Journal of Applied Mechanics and Engineering; 2019, 24, 4; 12-35
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fast convergence of the Coiflet-Galerkin method for general elliptic BVPs
Autorzy:
Akbari, H.
Powiązania:
https://bibliotekanauki.pl/articles/330950.pdf
Data publikacji:
2013
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
general stationary elliptic BVPs
Robin boundary condition
orthogonal Coifman wavelets
trivariate connection coefficients
fast convergence
Opis:
We consider a general elliptic Robin boundary value problem. Using orthogonal Coifman wavelets (Coiflets) as basis functions in the Galerkin method, we prove that the rate of convergence of an approximate solution to the exact one is O(2-nN) in the H1 norm, where n is the level of approximation and N is the Coiflet degree. The Galerkin method needs to evaluate a lot of complicated integrals. We present a structured approach for fast and effective evaluation of these integrals via trivariate connection coefficients. Due to the fast convergence rate, very good approximations are found at low levels and with low Coiflet degrees, hence the size of corresponding linear systems is small. Numerical experiments confirm these claims.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2013, 23, 1; 17-27
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 975

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