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Wyszukujesz frazę "variable parameters" wg kryterium: Temat


Wyświetlanie 1-5 z 5
Tytuł:
Analytical solutions to boundary value problem of free vibration of sandwich thin circular plates with discrete elements
Autorzy:
Żur, K. K.
Jaroszewicz, J.
Dragun, Ł.
Powiązania:
https://bibliotekanauki.pl/articles/265886.pdf
Data publikacji:
2015
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
free vibrations
non-homogeneous material
sandwich circular plate
variable parameters
annular mass
wibracje
płyta wielowarstwowa
zmienne parametry
Opis:
In the paper the influence function and the method of partial discretization in free axisymmetric vibration analysis of multilayered circular plates of constant and linearly variable thickness were presented. The effects of shear deformation and rotary inertia for the core as well as the facings were neglected. An analytical investigation based on the classical plate theory was made for the multilayered plate which satisfies Sokołowski’s condition. Discretization of mass and replacing stiffness of a fixed circular plate were presented. Formulas of influence matrix and Bernstein-Kieropian’s estimators for different steps of discretization were defined. The influence of variable distribution of parameters on the value of double estimators of natural basic and higher frequency of a sandwich circular plate was investigated.
Źródło:
International Journal of Applied Mechanics and Engineering; 2015, 20, 3; 617-627
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Variable-Intensity Running Training and Circuit Training on Selected Physiological Parameters of Soccer Players
Autorzy:
Ambroży, Tadeusz
Nowak, Mateusz
Omorczyk, Jarosław
Wrześniewski, Krzysztof
Ozimek, Mariusz
Duda, Henryk
Mucha, Dawid
Ceranowicz, Piotr
Pałka, Tomasz
Stanula, Arkadiusz
Mucha, Dariusz
Powiązania:
https://bibliotekanauki.pl/articles/1030576.pdf
Data publikacji:
2018
Wydawca:
Uniwersytet Szczeciński. Wydawnictwo Naukowe Uniwersytetu Szczecińskiego
Tematy:
circuit training
physiological parameters
soccer players
variable-intensity running training
Opis:
Proper planning of the training process based on individual LT and AT metabolic thresholds is essential to improve athletic performance. Development of endurance in soccer players is mainly based on continuous runs and variable-intensity runs, supplemented with strength conditioning and sport-specific training. The aim of the study was to analyse selected parameters of physical capacity of soccer players after 8-week variable-intensity running training and circuit training. The experiment was carried out in a group of 34 soccer players aged 21 to 26 years. The athletes were divided into two groups: 17 people in the experimental group and 17 people in the control group. The experimental group was involved in 30-minute tempo runs two times a week for 8 weeks with variable intensity at AT. In the same period, the control group performed two 60-minute continuous runs at the intensity of 70-75%HRmax. The determination of metabolic thresholds used two indirect tests: the multistage shuttle run test (beep test) and maximal lactate steady state test (MLSS) with author's own modification. In order to evaluate maximal heart rate (HRmax), the research procedure was started from the beep test (distance: 20 m). The speed at the first level was 8.5 km/h and increased with each level by 0.5 km/h. Training of the experimental group where variable exercise intensity was used caused a statistically significant increase in HRmax (by 1.9%) and blood lactate levels at the AT (by 20.5%). The training in the experimental group led to the statistically significant (p < 0.05) increase in the parameters of the following variables: HRmax (by 1.9%); lactate level (by 7.85); HR at the AT (by 1,9%); lactate level at the AT (by 20.5%). The assumptions of the experimental training did not cause statistically significant changes in pretest vs. posttest HRmax and blood lactate levels for the LT. Endurance training with high intensity is more effective in soccer players compared to training with moderate intensity. Development of special endurance in soccer should also assume the intensity and method of working similar to the method used during sport competition.
Źródło:
Central European Journal of Sport Sciences and Medicine; 2018, 23, 3; 25-35
2300-9705
2353-2807
Pojawia się w:
Central European Journal of Sport Sciences and Medicine
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dynamics of a mass variable drum winding a heavy rope
Autorzy:
Buśkiewicz, J.
Powiązania:
https://bibliotekanauki.pl/articles/38629421.pdf
Data publikacji:
2021
Wydawca:
Instytut Podstawowych Problemów Techniki PAN
Tematy:
angular momentum
two time parameters method
time-variable mass
dynamic equations
drum
Opis:
The paper focuses on a winch drum winding a heavy rope to present the variety of issues related to the dynamics of systems with rotating parts of time-varying mass. The dynamic motion equations for such systems are frequently either incorrect or derived under the assumption of mass constancy. When the mass variability is taken into account, simpler cases are discussed. The considerations on the angular momentum theorem enables formulating a new two time parameters form of the rotational motion equation for the system with time varying mass. Four cases are considered and different approaches of motion equations derivation are applied. The assumptions and solution methods of the analyzed systems as well as ambiguities and possible contradictions that may arise as a result of the trial of the problem formulation on the grounds of rigid body mechanics are discussed. The numerical simulations are presented.
Źródło:
Archives of Mechanics; 2021, 73, 5-6; 557-582
0373-2029
Pojawia się w:
Archives of Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Stanowisko laboratoryjne do wyznaczania parametrów termodynamicznych sprężarki tłokowej
Laboratory stand for determining piston compressor thermodynamic parameters
Autorzy:
Gawędzki, W.
Dziekan, A.
Hajto, P.
Powiązania:
https://bibliotekanauki.pl/articles/157042.pdf
Data publikacji:
2008
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
sprężarka tłokowa
parametry termodynamiczne
cykl termodynamiczny
pomiar szybkozmiennej temperatury
piston compressor
thermodynamic parameters
thermodynamic cycle
fast-variable temperature measurement
Opis:
W artykule omówiono stanowisko laboratoryjne do automatycznego wyznaczania parametrów i charakterystyk termodynamicznych sprężarki tłokowej, które może być również wykorzystane do badania innych typów obiektów, w których zachodzą przemiany termodynamiczne względnie dla celów dydaktycznych. Omówiono opracowane metody wyznaczania parametrów termodynamicznych, zastosowane układy kondycjonowania sygnałów oraz sposoby kalibracji torów pomiarowych. Opracowany system umożliwia pomiar chwilowych wartości temperatury, objętości czynnej w cylindrze sprężarki, ciśnień oraz przepływu powietrza, a także wyznaczenie cyklu termodynamicznego (p=f(V)) oraz wyznaczenie bilansu energetycznego i określenie sprawności sprężarki.
The paper presents the laboratory stand for automatic measurements of thermodynamic parameters and characteristics of a piston compressor. The stand can also be used for investigations of thermodynamic parameters of other systems as well as for didactics. The methods used for determining the thermodynamic parameters and calibrating the measurement equipment are discussed. The system enables measurements of the instantaneous values of temperature, active volume of a compressor cylinder, pressure and air flow velocity. The thermodynamic cycle (p=f(V)), energy balance and compressor efficiency factor can also be determined.
Źródło:
Pomiary Automatyka Kontrola; 2008, R. 54, nr 12, 12; 883-886
0032-4140
Pojawia się w:
Pomiary Automatyka Kontrola
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Some applications of Noether’s theorem
Autorzy:
Montiel-Pérez, J. Yaljá
López-Bonilla, J.
López-Vázquez, R.
Vidal-Beltrán, S.
Powiązania:
https://bibliotekanauki.pl/articles/1166045.pdf
Data publikacji:
2018
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Complex Riemann-Silberstein vector
Duality rotations
Ignorable variable
Invariance of the action
Lanczos variational method
Linear differential equation of second order
Maxwell equations
Noether’s theorem
Variation of parameters
Variational symmetry
Opis:
If the action S= ∫_(t_1)^(t_2)▒〖L(q,〗 (q,) ̇t) dt is invariant under the infinitesimal transformation t ̃=t+ε τ(q,t), q ̃_r= q_r+ε ξ_r (q,t),r=1,… ,n, with ε=constant ≪1, then the Noether’s theorem permits to construct the corresponding conserved quantity. The Lanczos approach employs to ε= q_(n+1) as a new degree of freedom, thus the Euler-Lagrange equation for this new variable gives the Noether’s constant of motion. Torres del Castillo and Rubalcava-García showed that each variational symmetry implies the existence of an ignorable coordinate; here we apply the Lanczos approach to the Noether’s theorem to motivate the principal relations of these authors. The Maxwell equations without sources are invariant under duality rotations, then we show that this invariance implies, via the Noether’s theorem, the continuity equation for the electromagnetic energy. Besides, we demonstrate that if we know one solution of p(x)y''+q(x)y'+r(x)y=0, then this Lanczos technique allows obtain the other solution of this homogeneous linear differential equation.
Źródło:
World Scientific News; 2018, 106; 69-80
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-5 z 5

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