Large Amplitude Pulsatile Water Flow Across an Orifice

1975 ◽  
Vol 97 (1) ◽  
pp. 92-95 ◽  
Author(s):  
E. L. Yellin ◽  
C. S. Peskin
Keyword(s):  
Large Amplitude ◽  
Heart Valves ◽  
Equation Of Motion ◽  
Separated Flows ◽  
Prosthetic Heart Valves ◽  
One Dimensional ◽  
Water Flows ◽  
Lumped Parameter ◽  
Dimensional Equation ◽  
The One

The pressure-flow relations of large amplitude pulsatile water flows across an orifice have been investigated theoretically and experimentally. By retaining the unsteady term in the one-dimensional equation of motion, and by allowing the jet area to be a function of distance in the continuity equation, a lumped parameter relationship between pressure drop and flow has been developed which reflects the influence of inertia and dissipation. The results are applicable to the analysis of natural and prosthetic heart valves under normal and pathologic conditions. Within the physiologically possible conditions of frequency and flow rate, unsteady separated flows exhibit the same energy losses as comparable steady separated flows. Thus, the flow is quasi-steady, even when the waveforms and temporal relations indicate a significant inertial influence.

scholarly journals LOCAL FRACTIONAL SUPERSYMMETRY FOR ALTERNATIVE STATISTICS

1996 ◽  
Vol 11 (11) ◽  
pp. 899-913 ◽  
Author(s):  
N. FLEURY ◽  
M. RAUSCH DE TRAUBENBERG
Keyword(s):  
Group Theory ◽  
Braid Group ◽  
Equation Of Motion ◽  
Coset Space ◽  
One Dimensional ◽  
The One

A group theory justification of one-dimensional fractional supersymmetry is proposed using an analog of a coset space, just like the one introduced in 1-D supersymmetry. This theory is then gauged to obtain a local fractional supersymmetry, i.e. a fractional supergravity which is then quantized à la Dirac to obtain an equation of motion for a particle which is in a representation of the braid group and should describe alternative statistics. A formulation invariant under general reparametrization is given by means of a curved fractional superline.

Contractile Filament Stress in the Left Ventricle and its Relationship to Wall Stress

1979 ◽  
Vol 101 (4) ◽  
pp. 225-231 ◽  
Author(s):  
E. S. Grood ◽  
C. A. Phillips ◽  
R. E. Mates
Keyword(s):  
Three Dimensional ◽  
Wall Stress ◽  
One Dimensional ◽  
Muscle Work ◽  
Lumped Parameter ◽  
Pressure Development ◽  
The One ◽  
Active Force Generation ◽  
Muscle Models ◽  
Significant Underestimation

A three-dimensional composite model of heart muscle is proposed, consisting of one-dimensional (uniaxial) active contractile filaments embedded in a passive elastic binder. Equations are developed which relate the force developed by the filaments to the local tissue stress. An approximate analysis is employed to determine the time variation of the contractile filament stress throughout the cardiac cycle from catheterization data. Results from 15 patients with normal left ventricles demonstrate that the stress developed by the contractile filaments is up to 25 percent more tensile than the wall stress, and that the binder stress is compressive during most of systole. In contrast, the one-dimensional lumped parameter muscle models previously employed predict active (CE) stresses less tensile than the wall stress and binder (PE) stresses that are tensile. We conclude that the use of a one-dimensional muscle model results in a significant underestimation of the active force generation required for pressure development and the power requirements for ejection. Prior studies relating muscle work and power to ventricular oxygen consumption should be re-examined in this light.

Analysis of the Containment Thermal-Hydraulic Behavior of a Small Reactor During Loss of Coolant Accident

2017 ◽  
Author(s):  
Qian Lin ◽  
Weizhong Zhang
Keyword(s):  
Cooling System ◽  
Three Dimensional ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
One Dimensional ◽  
Loss Of Coolant Accident ◽  
Lumped Parameter ◽  
Loss Of Coolant ◽  
Calculation Results ◽  
The One

The containment thermal hydraulics of a small reactor during loss of coolant accident (LOCA) is studied by a lumped parameter one-dimensional model and a three-dimensional model. The capability of a kind of heat exchanger type passive containment cooling system (PCCS) is analyzed by the one-dimensional model. The calculation results show that, the decay heat can be removed and the containment pressure can be decreased by the proposed PCCS. The steam and non-condensable gas (the air) distribution in the containment is investigated, the mixing and stratification behaviors are analyzed for several different cases, in which the PCCS and condenser are located at higher, base or lower position. The sensitivity analysis of the PCCS elevation shows that, in despite of the different gas stratification, the containment pressures are nearly the same. Similar conclusions can be obtained by the one-dimensional model and three-dimensional model. The preliminary results may indicate that, the designed PCCS and condenser can be located at a lower part, which will be benefit for the economy of the small reactor or meet other requirements.

scholarly journals Radial Imbibition in Paper under Temperature Differences

Fluids ◽  
2019 ◽  
Vol 4 (2) ◽  
pp. 86
Author(s):  
Abel López-Villa ◽  
Abraham Medina ◽  
F. J. Higuera ◽  
Jonatan R. Mac Intyre ◽  
Carlos Alberto Perazzo ◽  
...  
Keyword(s):  
Experimental Data ◽  
Surface Tension ◽  
Porous Material ◽  
Radial Temperature ◽  
Temperature Variations ◽  
One Dimensional ◽  
Blotting Paper ◽  
Dimensional Equation ◽  
The One ◽  
Account Temperature

Spontaneous radial imbibition into thin circular samples of porous material when they have been subjected to radial temperature differences was analyzed theoretically and experimentally. The use of the Darcy equation allowed us to take into account temperature variations in the dynamic viscosity and surface tension in order to find the one-dimensional equation for the imbibition fronts. Experiments using blotting paper showed a good fit between the experimental data and theoretical profiles through the estimation of a single parameter.

scholarly journals Análisis de un oscilador no lineal utilizando el método de Euler en una planilla de cálculo

2019 ◽  
Vol 65 (2 Jul-Dec) ◽  
pp. 200
Author(s):  
A. Suárez ◽  
And F. Tornaría
Keyword(s):  
Video Analysis ◽  
Temporal Evolution ◽  
Nonlinear Oscillations ◽  
Equation Of Motion ◽  
Euler Method ◽  
Experimental Physics ◽  
One Dimensional ◽  
University Courses ◽  
The One

Se analizan teórica y experimentalmente las oscilaciones unidimensionales no lineales de un imán que está unido a un resorte e interactúacon un grupo de imanes. Se resuelve numéricamente la ecuación de movimiento del sistema utilizando el método de Euler en una planillade cálculo. Experimentalmente, la evolución temporal de la posición se obtiene mediante análisis de video. La correspondencia entre laspredicciones del modelo y los datos experimentales deja en evidencia la potencialidad de las herramientas utilizadas. La sencillez de lapropuesta presentada permite su aplicación en los primeros cursos universitarios de Física experimental. The one-dimensional nonlinear oscillations of a magnet attached to a spring and interacting with a set of magnets are analyzed theoreticallyand experimentally. The equation of motion is solved numerically using the Euler method in a spreadsheet. The temporal evolution of theposition is obtained using video analysis. The correspondence between the data and the predictions of the model shows the potential of thetools employed. The simplicity of the approach allows its application in the first university courses of experimental Physics.   

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