The fluctuation pressure that an infinitely extended fluid membrane exerts on two enclosing parallel hard walls is computed. Variational perturbation theory is used to extract the hard-wall limit from a perturbative expansion through six loops obtained with a smooth wall potential. Our result alpha=0.0821 +/- 0.0005 for the constant conventionally parametrizing the pressure lies above earlier M...

We measured the distribution of contact area and pressure between the acetabulum and the femoral head of cadaveric pelves in three different conditions: intact, with an operatively created fracture of the posterior wall, and after anatomical reduction and fixation of the fracture with a buttress plate and interfragmentary screws. The study involved eight cadaveric hip joints from five pelves lo...

BACKGROUND Many cardiovascular diseases, such as aortic dissection, frequently occur on the aortic arch and fluid-structure interactions play an important role in the cardiovascular system. Mechanical stress is crucial in the functioning of the cardiovascular system; therefore, stress analysis is a useful tool for understanding vascular pathophysiology. The present study is concerned with the s...

The purpose of this study was to determine the influence of radial motion of an arterial wall on the shear stress that flowing blood imposes on the wall (wall shear stress). Wall shear stress is known to influence endothelial cell function and may play a role in atherogenesis, but its magnitude and distribution in the circulation are not well understood. To simulate arterial wall motion, we use...

Left ventricular hypertrophy in left ventricular pressure overload occurs in response to excessive work load imposed on the left ventricle by increased impedance to ejection. Right ventricular hypertrophy may occur in patients with these findings, but has been considered to be secondary to pulmonary hypertension. To determine the frequency of right ventricular hypertrophy and its relation to in...

LAPLACE’S LAW plays a mayor role in explanations of the wall tension of structures like blood vessels, the bladder, the uterus in pregnancy, bronchioles, eyeballs, and the behavior of aneurisms or the enlarged heart. The general relation of Laplace’s law, expressing that the product of the radius of curvature (r) and pressure (P) is equal to wall tension (T) (i.e., r P T), is quite simple, but ...

BACKGROUND Biomechanical factors influence stress in the aortic wall. The aim of this study was to assess how the diameter and shape of the vessel, blood pressure and longitudinal systolic aortic stretching (SAS) caused by the contraction of the myocardium influence stress in the aortic wall. METHODS Three computational models of the non-dilated aorta and aneurysms of the ascending aorta and ...

Pollen tube growth is central to the sexual reproduction of plants and is a longstanding model for cellular tip growth. For rapid tip growth, cell wall deposition and hardening must balance the rate of osmotic water uptake, and this involves the control of turgor pressure. Pressure contributes directly to both the driving force for water entry and tip expansion causing thinning of wall material...

We experimentally investigate a partially shrouded sonic jet (a free-jet shielded by solid wall-extension on one side) exiting from planar nozzle at two different pressure ratio ($\zeta=4$ and $5$). show that the inherent unsteadiness shock-induced flow separation wall emitted noise in far-field is strongly coupled through series of experiments like high-speed schlieren, wall-static pressure, u...

This work is devoted to wall-pressure fluctuation analysis. The object of investigation was an isolated helicopter fuselage. Investigation carried out by experimental and numerical methods. Numerical simulation based on RANS DES approaches. experiment in a lowspeed wind tunnel with open test section. Wall-pressure measurement high-frequency pressure probes ENDEVCO 8510B-2. results were compared...