Pulsatile Flow Behavior in Elastic Systems Containing Wave Reflection Sites

1969 ◽  
Vol 91 (1) ◽  
pp. 95-102 ◽  
Author(s):  
J. L. Campbell ◽  
T. Yang
Keyword(s):  
Pulsatile Flow ◽  
Analytical Study ◽  
Wave Reflection ◽  
Flow Behavior ◽  
Reasonable Accuracy ◽  
One Dimensional ◽  
Test Conditions ◽  
Elastic Systems ◽  
Mass Flow Rates ◽  
Human Cardiovascular System

An analytical study is presented for one-dimensional, pulsatile flow of an incompressible fluid in systems of elastic tubing. Nonlinear terms are retained in the system of describing equations. Three experimental test systems with characteristics similar in some respects to those of the human cardiovascular system are described. These systems were used for experimental verification of the analytical predictions. Comparisons of the analytical predictions and experimental results show that pressures, mass flow rates, and velocities can be predicted with reasonable accuracy for all test conditions employed on the three models.

scholarly journals A psychrometric model to assess the biological decay of the SARS-CoV-2 virus in aerosols

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11024
Author(s):  
Clive B. Beggs ◽  
Eldad J. Avital
Keyword(s):  
Air Temperature ◽  
Vapour Pressure ◽  
Half Life ◽  
Analytical Study ◽  
Decay Constant ◽  
Meteorological Data ◽  
Environmental Parameters ◽  
Published Data ◽  
Reasonable Accuracy ◽  
The Impact

There is increasing evidence that the 2020 COVID-19 pandemic has been influenced by variations in air temperature and humidity. However, the impact that these environmental parameters have on survival of the SARS-CoV-2 virus has not been fully characterised. Therefore, an analytical study was undertaken using published data to develop a psychrometric model to assess the biological decay rate of the virus in aerosols. This revealed that it is possible to describe with reasonable accuracy (R2 = 0.718, p < 0.001) the biological decay constant for the SARS-CoV-2 virus using a regression model with enthalpy, vapour pressure and specific volume as predictors. Applying this to historical meteorological data from London, Paris and Milan over the pandemic period, produced results which indicate that the average half-life of the virus in aerosols outdoors was in the region 13–22 times longer in March 2020, when the outbreak was accelerating, than it was in August 2020 when epidemic in Europe was at its nadir. However, indoors, this variation is likely to be much less. As such, this suggests that changes in virus survivability due the variations in the psychrometric qualities of the air might influence the transmission of SARS-CoV-2.

scholarly journals Disordered elastic systems and one-dimensional interfaces

2012 ◽  
Vol 407 (11) ◽  
pp. 1725-1733 ◽  
Author(s):  
E. Agoritsas ◽  
V. Lecomte ◽  
T. Giamarchi
Keyword(s):  
One Dimensional ◽  
Elastic Systems

An Analytical Study of Cryosurgery in the Lung

1992 ◽  
Vol 114 (4) ◽  
pp. 467-472 ◽  
Author(s):  
J. C. Bischof ◽  
J. Bastacky ◽  
B. Rubinsky
Keyword(s):  
Finite Difference ◽  
Analytical Study ◽  
Outer Boundary ◽  
Temperature Profiles ◽  
One Dimensional ◽  
Thermal Phenomenon ◽  
Healthy Lung Tissue ◽  
Close Form ◽  
Finite Difference Techniques ◽  
Healthy Lung

The process of freezing in healthy lung tissue and in tumors in the lung during cryosurgery was modeled using one-dimensional close form techniques and finite difference techniques to determine the temperature profiles and the propagation of the freezing interface in the tissue. A thermal phenomenon was observed during freezing of lung tumors embedded in healthy tissue, (a) the freezing interface suddenly accelerates at the transition between the tumor and the healthy lung, (b) the frozen tumor temperature drops to low values once the freezing interface moves into the healthy lung, and (c) the outer boundary temperature has a point of sharp inflection corresponding to the time at which the tumor is completely frozen.

Floating Membrane Breakwater

1996 ◽  
Vol 118 (1) ◽  
pp. 46-52 ◽  
Author(s):  
A. N. Williams
Keyword(s):  
Wave Reflection ◽  
Structural Parameters ◽  
Unit Length ◽  
Fluid Motion ◽  
Integral Equation Method ◽  
Equation Of Motion ◽  
Boundary Integral ◽  
Mooring Line ◽  
Hydrodynamic Properties ◽  
One Dimensional

The hydrodynamic properties of a flexible floating breakwater consisting of a membrane structure attached to a small float restrained by moorings are investigated theoretically. The tension in the membrane is achieved by hanging a clump weight from its lower end. The fluid motion is idealized as linearized, two-dimensional potential flow and the equation of motion of the breakwater is taken to be that of a one-dimensional membrane of uniform mass per unit length subjected to a constant axial force. The boundary integral equation method is applied to the fluid domain, and the dynamic behavior of the breakwater is also described through an appropriate Green function. Numerical results are presented which illustrate the effects of the various wave and structural parameters on the efficiency of the breakwater as a barrier to wave action. It is found that the wave reflection properties of the structure depend strongly on the membrane length, the magnitude of the clump weight, and the mooring line stiffness, while the membrane weight and excess buoyancy of the system are of lesser importance.

A Mathematical Description for the Stress-Strain Behavior of Annealed 2 1/4 Cr-1 Mo Steel

1976 ◽  
Vol 98 (2) ◽  
pp. 118-125 ◽  
Author(s):  
R. L. Klueh ◽  
T. L. Hebble
Keyword(s):  
Mathematical Description ◽  
Flow Behavior ◽  
True Strain ◽  
Empirical Relationship ◽  
Tensile Tests ◽  
Strain Rates ◽  
Strain Behavior ◽  
Test Conditions ◽  
Wide Range ◽  
Strain Data

We have conducted a detailed series of tensile tests on one heat of annealed 2 1/4 Cr-1 Mo steel over the range 25 to 593°C (75 to 1100°F) and at nominal strain rates of 0.4, 0.04, 0.004, and 0.0004/min. To determine an empirical relationship to represent the flow behavior, we fitted the true-stress true-strain data from these tests to several proposed models. The models fit were those proposed by Hollomon, Ludwik, Ludwigson, and Voce. From a comparison of the standard error of estimate, the Voce equation was concluded to be the best mathematical description of the data under most test conditions and the best single representation over the wide range of test conditions.

Intervalley kinetic energy terms in the effective mass equation: a one-dimensional analytical study

1989 ◽  
Vol 67 (9) ◽  
pp. 896-903 ◽  
Author(s):  
Lorenzo Resca
Keyword(s):  
Kinetic Energy ◽  
Effective Mass ◽  
Analytical Study ◽  
Three Dimensional ◽  
Real Space ◽  
The Other ◽  
Alternative Formulation ◽  
One Dimensional ◽  
Symmetry Properties ◽  
Band Case

We show that a one-dimensional analytical study allows us to test and clarify the derivation, assumptions, and symmetry properties of the intervalley effective mass equation (IVEME). In particular, we show that the IVEME is consistent with a two-band case, and is in fact exact for a model that satisfies exactly all its assumptions. On the other hand, an alternative formulation in k-space that includes intervalley kinetic energy terms is consistent with a one-band case, provided that intra-valley kinetic energy terms are also calculated consistent with one band. We also show that the standard symmetry assumptions for both real space and k-space formulations are not actually exact, but are consistent with a "total symmetric" projection, or with taking spherical averages in a three-dimensional case.

The Formation of Stratified Combustible Mixtures in Closed Tubes by Molecular and Convective Diffusions

1985 ◽  
Vol 107 (3) ◽  
pp. 348-353 ◽  
Author(s):  
O. Badr
Keyword(s):  
Theoretical Study ◽  
Concentration Profiles ◽  
Dimensional Model ◽  
One Dimensional ◽  
Test Conditions ◽  
Experimental Justification ◽  
The One ◽  
Combustible Mixtures

This paper describes a theoretical study on the formation of stratified combustible mixtures in closed long vertical flame tubes. The concentration profiles of the fuel (methane) in air, just before ignition took place, were predicted using a one-dimensional model involving molecular and convective diffusional processes. Phenomenological and experimental justification of the one-dimensional assumption was given and some of the predicted data were compared with experiment for different test conditions. The model appears to have successfully predicted the concentration profiles in some situations where other models failed.

Sign in / Sign up

Export Citation Format

Share Document