The paper presents a survey of recent results in the area of controllability of second order dynamical systems. Controllability problem for finite and infinite dimensional, linear, semilinear, deterministic and stochastic dynamical systems (with delays and undelayed) is taken into consideration. Different types of controllability are discussed.
2
Dostęp do pełnego tekstu na zewnętrznej witrynie WWW
The paper contains derivation of reciprocity principle for boundary problem of magnetostriction. The results obtained in this work can become the theoretical basis to formulate the numerical solutions of different scientific and engineering problems connected with magnetostrictive materials.
3
Dostęp do pełnego tekstu na zewnętrznej witrynie WWW
The paper shows how to transform a given nonlinear boundary problem of magnetostriction into a variational formulation. A sufficient condition for the construction of variational principle is formulated in the theorem of VAINBERG. The results obtained in this work can become the theoretical basis to formulate the numerical solutions of different scientific and engineering problems connected with magnetostrictive materials.
4
Dostęp do pełnego tekstu na zewnętrznej witrynie WWW
The paper contains derivation of reciprocity principle for boundary problem of electrostriction. The results obtained in this work can become the theoretical basis to formulate the numerical solutions of different scientific and engineering problems connected with electrostrictive materials.
5
Dostęp do pełnego tekstu na zewnętrznej witrynie WWW
The paper shows how to transform a given nonlinear boundary problem of electrostriction into a variational formulation. A sufficient condition for the construction of variational principle is formulated in the theorem of VAINBERG. The results obtained in this work can become the theoretical basis to formulate the numerical solutions of different scientific and engineering problems connected with electrostrictive materials.
6
Dostęp do pełnego tekstu na zewnętrznej witrynie WWW
The paper contains derivation of reciprocity theorem for boundary problem of nonlinear piezoelectricity. The results obtained in this work can become the theoretical basis to formulate the numerical solutions of different scientific and engineering problems connected with piezoelectric materials.
7
Dostęp do pełnego tekstu na zewnętrznej witrynie WWW
The paper contains balance equations, constitutive equations and initial-boundary value conditions of linear higrothermopiezoelectricity. The results obtained in this work can become the theoretical basis to formulate the numerical solutions of different scientific and engineering problems connected with piezoelectric materials.
8
Dostęp do pełnego tekstu na zewnętrznej witrynie WWW
The paper contains derivation of reciprocity theorem for initial-boundary value problem of linear thermopiezoelectricity. The results obtained in this work can become the theoretical basis to formulate the numerical solutions of different scientific and engineering problems connected with piezoelectric materials.
10
Dostęp do pełnego tekstu na zewnętrznej witrynie WWW
The article presents basic problems concerning durability and degradation of old brick walls in monumental and industrial building. The work contains the impact of quality of brick and lime mortar on degradation rate. It also includes problems of masonry resistance to factors like moisture, soluble salts, air pollution, microorganisms, thermal changes and mechanical factors.
11
Dostęp do pełnego tekstu na zewnętrznej witrynie WWW
Modeling energy transfer in salt-affected monumental building walls requires knowledge of heat, salt, and water interaction. Effective thermal conductivity is a very important parameter in the thermal performance analysis of building walls. In this paper the effect of soluble salts on the effective thermal conductivity of porous materials is investigated and the MAXWELL-EUCKEN model is evaluated.
12
Dostęp do pełnego tekstu na zewnętrznej witrynie WWW
The measurements of water vapour diffusion coefficient in porous materials generate many specific errors. In the paper two ways of this coefficient evaluation are compared: a classical one (deterministic) and one based on simulation method SBRA, with Monte Carlo approach.
13
Dostęp do pełnego tekstu na zewnętrznej witrynie WWW
Effective thermal conductivity of porous building materials is a very important parameter particularly in the thermal performance analysis of building envelopes. There are many different analytical models to estimate or calculate effective thermal conductivity of N–phase porous media partially or fully filled with air and/or water. In this paper the selected models of effective thermal conductivity for 2 and 3–phase porous material are selected and reviewed.
14
Dostęp do pełnego tekstu na zewnętrznej witrynie WWW
The diffusion energy causes significant difficulties with its evaluation and physical interpretation. In this paper an attempt of estimation of energy of diffusion in case of binary mixture of dry air and water vapour was made. It was pointed out that its magnitude is negligible low in comparison with internal partial energy.
15
Dostęp do pełnego tekstu na zewnętrznej witrynie WWW
Frost damages of porous building materials (such as concrete) have been observed in a number of structures that are exposed to water and subfreezing temperature. As the frost damages are associated with the freezing of water, so the physical properties of water and ice near freezing point are reviewed. The macroscopic process of the freezing of water has also been analysed.
Dokonano próby oszacowania współczynnika dyfuzji pary wodnej w układach warstwowych. Zestawy pomiarowe składały się z gipsu i folii paroprzepuszczalnych różnych rodzajów. W obliczeniach zastosowano model ośrodka wieloskładnikowego, wykorzystując wyniki pomiarów laboratoryjnych w komorze klimatycznej.
EN
The estimation of vapour transport coefficient in multilayer systems has been achieved. The measuring set was built with layer of gypsum covered with water permeable foils of different properties. Model of multicomponent body with use of laboratory measuring results from climatic chamber is built.
The simple system of coupled non-linear differential equation is solved by the (Adomian) decomposition method which provides an analytical approximation requiring no linearization. The method presents a new approach to non-linear problems.
PL
Przy wykorzystaniu metody dekompozycji (Adomiana) rozwiązano prosty układ nieliniowych równań różniczkowych zwyczajnych, uzyskując analityczną aproksymację rozwiązania bez konieczności linearyzacji równań wyjściowych.
W artykule rozważamy nieliniowe równania różniczkowe zwyczajne, których rozwiązanie może być uzyskane metodą dekompozycji. Rozwiązanie- na ogół w postaci szybko zbieżnego szeregu - może być weryfikowane na każdym etapie aproksymacji. Metoda jest ilustrowana dwoma przykładami.
EN
In this paper, we consider nonlinear differential equations whose solution can be obtained by the decomposition method. The approximation - generally a very rapidły convergent series - can be verified at any stage of approximation. The method is illustrated with two examples.
W pracy analizowano nieliniowe równanie różniczkowe przewodnictwa cieplnego. Porównano dwie różne postacie funkcji materiałowych. Otrzymano zamkniętą, analityczną postać pola temperatury. Rozwiązanie nieliniowego równania różniczkowego otrzymano przy wykorzystaniu metody dekompozycji.
EN
Nonlinear differential equation of heat conduction is analyzed. Two different fonns of material functions are compared. Closed form analytical expression for temperature is obtained. The solution of the nonlinear differential equation has been obtained by the decomposition method.