PL
 |
EN
Preferencje help
Polish version English version Język
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 15

Liczba wyników na stronie
first rewind previous Strona / 1 next fast forward last
Wyniki wyszukiwania
help Sortuj według:

help Ogranicz wyniki do:
first rewind previous Strona / 1 next fast forward last
1
Content available Evaluation of the accuracy of the postural stability measurement with the Y-Balance Test based on the levels of the biomechanical parameters
Walaszek R., Chwała W., Walaszek K., Burdacki M., Błaszczuk J.
Acta of Bioengineering and Biomechanics
|
2017
|
Vol. 19, no. 2
121--128
EN
The testing of dynamic balance involves tests that assess the muscle control of spatial changes of the position of the centre of gravity over the base of support. The purpose of this work was to determine the structure of the Y-balance test and its accuracy based on the measurements of strength performance of the muscles acting on the knee joint, as well as the flexibility and balance in boys aged 14 years. Methods: The study included 43 schoolboys regularly participating in physical education lessons. The examination of postural stability was conducted with the use of the Y-balance test. The measurements of muscle strength and of resistance to fatigue of the extensors and flexors of knee joints in isometric contraction were performed on a measurement stand in a standard position with the use of tensometric sensors. The measurement of mobility range of the lower extremity joints was performed according to the SFTR. The examination of balance was performed with the use of the modified ‘Flamingo balance test’. Results: The factor structure of the Y-balance test results for the left and right lower extremities is similar and includes five principal independent factors that characterise the structure of analysed variables. They explain 76% and 74% of communality in total for the left and the right extremity, respectively. Conclusions: The extracted factor structure points to a hybrid structure of the Y-balance test and shows its accuracy in the measurements of the lower limb joint mobility and strength performance of knee joint extensors.
2
Content available The influence of thermal actions and complex support conditions on the mechanical state of sandwich structure
Błaszczuk J., Pozorski Z.
Journal of Applied Mathematics and Computational Mechanics
|
2013
|
Vol. 12, nr 4
13--21
EN
The paper concerns the problem of the influence of thermal actions on the structural behavior of sandwich panels with unspecified elastic supports. An ordinary sandwich panel theory is used. The boundary conditions have the arbitrary form of elastic supports. The solution of a statically undetermined system with limitations of horizontal displacement and rotation is derived. The illustrative examples are presented and the problem solution is discussed.
3
Content available remote Structural Behavior of Sandwich Panels with External Deep-Profiled and Internal Soft Facing
Pozorski Z., Sol R., Szajda J., Błaszczuk J.
Engineering Transactions
|
2013
|
Vol. 61, iss. 3
173--184
EN
Sandwich panels made of deep-profiled steel facesheet, thick and soft PUR core and thin aluminum facesheet are considered. The structural behavior of the panel in two arrangements is analyzed by the way of real experiments. Three-point bending tests were carried out. The laboratory tests unraveled non-linear characteristics of structural behavior. The local instability of the compressed faces was observed. The real experiments were compared with the results of numerical simulations.
4
Content available remote The analysis of the influence of core compression effect on the determination of the shear modulus of the sandwich panel core
Błaszczuk J., Pozorski Z.
Prace Naukowe Instytutu Matematyki i Informatyki Politechniki Częstochowskiej
|
2012
|
Vol. 11, nr 2
5-13
EN
The paper concerns the problem of the influence of core compression on core shear modulus determination. Two experimental methods of shear modulus determination are discussed. These methods are based on the estimation of the relation between bending and shear effects. Using the ordinary sandwich panel theory. The appropriate examples of the core compression influence are presented and discussed.
5
Content available remote Engineering aspects of the mathematical model of deep-profiled sandwich panel
Błaszczuk J., Pozorski Z.
Prace Naukowe Instytutu Matematyki i Informatyki Politechniki Częstochowskiej
|
2011
|
Vol. 10, nr 2
31-42
EN
The paper concerns the problem of static analysis of a deep-profiled sandwich panel. Equilibrium conditions in the form of differential equations are discussed. The solutions to example problems are given taking into account boundary conditions. The effects of transversal load and thermal excitations are presented and discussed.
6
Content available remote Engineering aspects of structural response of multi-span sandwich panels
Błaszczuk J., Pozorski Z.
Prace Naukowe Instytutu Matematyki i Informatyki Politechniki Częstochowskiej
|
2010
|
Vol. 9, nr 2
5-15
EN
The paper concerns a problem of static response of multi-span sandwich panels.The effects of transversal load and thermal actions are compared. The influence of material parameters on the sandwich behaviour is discussed. The examples illustrate practical approach to the problem of optimal design.
7
Content available remote Force distribution in granular systems with and without friction
Błaszczuk J.
Prace Naukowe Instytutu Matematyki i Informatyki Politechniki Częstochowskiej
|
2009
|
Vol. 8, nr 2
21-27
EN
Force distribution in granular media is discussed in this paper. The proper estimation of the force network has become a challenging issue because of a tendency to optimize packing processes. The aim of the study is numerical analysis of regular packings of grains in the frictionless and frictional 2D systems, as well as assessment of force distribution in static granular media and analysis of the influence of the load type and system size on force distribution.
8
Content available remote Mean-Field energy of elementary grain arrangements in wet granular ensembles
Błaszczuk J.
Prace Naukowe Instytutu Matematyki i Informatyki Politechniki Częstochowskiej
|
2008
|
Vol. 7, nr 1
11-15
EN
The energy of elementary grain arrangements in wet granular system is analyzed within the Mean Field Approximation. For an ensemble of vibrating grain it is calculated how the mean free energy of a grain depends on its surface curvature and porosity.
9
Content available remote Genetic algorithm approach to force chains in 2D granular packings
Kęsy J., Domański Z., Błaszczuk J.
Prace Naukowe Instytutu Matematyki i Informatyki Politechniki Częstochowskiej
|
2007
|
Vol. 6, nr 1
99-102
EN
We study the geometry of patterns formed by forces in 2D models of granular stacking using a genetic algorithm. As a fitness function we employ an entropy measure based on probability density functions of force-chain-arm lengths computed for different underlying lattice geometries.
10
Content available remote Application of the Lipschitz exponent and the wavelet transform to function discontinuity estimation
Błaszczuk J., Pozorski Z.
Prace Naukowe Instytutu Matematyki i Informatyki Politechniki Częstochowskiej
|
2007
|
Vol. 6, nr 1
23-29
EN
The paper concerns the problem of the application of the Discrete Wavelet Transform and the Lipschitz exponent to an estimation of function differentiability. The influence of number of discrete data (measurements points) and a class of function on the discontinuity indicator is analyzed. The problem is discussed on the example of functions which represent a structural response of a mechanical static system.
11
Content available remote An effective toroidal approximation for free liquid surface between ellipsoidal grains
Błaszczuk J., Biernat G., Domański Z.
Prace Naukowe Instytutu Matematyki i Informatyki Politechniki Częstochowskiej
|
2006
|
Vol. 5, nr 1
9-14
EN
The capillary bridge between ellipsoidal grains is modelled within an effective toroidal approximation. We analyse the case when major semi axes of grains are parallel.
12
Content available remote Toroidal approximation for capillary bridges between ellipsoidal grains
Błaszczuk J., Biernat G., Domański Z.
Prace Naukowe Instytutu Matematyki i Informatyki Politechniki Częstochowskiej
|
2005
|
Vol. 4, nr 1
13-17
EN
The capillary bridge between ellipsoidal grains is modelled within a toroidal approximation and the cohesive energy as function of grain's size, wetting angle and liquid content is computed. Some substrate-liquid examples are considered.
13
Content available remote Relaxation time in wet granular 2D systems of nonspherical particles
Błaszczuk J., Domański Z.
Prace Naukowe Instytutu Matematyki i Informatyki Politechniki Częstochowskiej
|
2004
|
Vol. 3, nr 1
13--18
EN
We apply the genetic algorithms - search procedures, to study the relaxation process in two-dimensional wet granular medium of non-spherical grains. We examine the equilibration of granulates under so-called tap dynamics and examine the dependence of relaxation times on system topology and on boundary conditions. Numerical computation are performed in the framework of genetic algorithm for sizes up to N = 2002 sites.
14
Content available remote Energy spectrum of frustrated granular materials
Błaszczuk J., Domański Z.
Prace Naukowe Instytutu Matematyki i Informatyki Politechniki Częstochowskiej
|
2003
|
Vol. 2, nr 1
25--29
EN
We study the statistical properties of low lying energy states for some special models of two dimensional frustrated granular materials.
15
Content available remote Upakowanie sfrustrowanego układu granularnego
Błaszczuk J., Domański Z.
Prace Naukowe Instytutu Matematyki i Informatyki Politechniki Częstochowskiej
|
2002
|
Vol. 1, nr 1
29--32
PL
Rozpatrywany jest model sieciowy niejednorodnego układu granularnego składającego się z dwóch rodzajów cząstek. Układ jest strukturalnie niejednorodny z możliwością występowania geometrycznej frustracji. Numerycznie analizowane są konfiguracje odpowiadające stanowi upakowania gęstego w obecności frustracji.
first rewind previous Strona / 1 next fast forward last
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.