Search results for "VELOCITY"

Effects of Rastering Velocity on Electrospun Polyeurthane Structure and Mechanical Properties

2010

Computation of flow velocity in rough channels

2006

Accurate estimate of flow-velocity profile is of crucial importance both for scientific purposes and for solving numerous engineering problems that include, among others, sediment transport, contaminant transport, flow resistance evaluation. This paper presents a new empirical equation to represent the vertical velocity profile. The proposed equation is essentially a modified form of the well-known logarithm law of the wall and contains three parameters having a clear physical meaning. The applicability of the equation and its accuracy assessment for different hydraulic conditions, including non-uniform conditions, is verified by using experimental data obtained by different sources. The va…

The Effect of Periodontal Treatment on the Reactive Hyperemia Index. A 1-Year Follow-Up Pilot Study

2022

BackgroundPeriodontitis is a chronic multifactorial inflammatory disease of the supportive tissues of the teeth. In more recent years, remarkable epidemiological and pathophysiological associations between periodontitis and cardiovascular disease (CVD) have been presented. Whether or not treatment of periodontitis is valuable for primary or secondary prevention of cardiovascular disease, has not yet been fully established. In this practice-based pilot study we focused on primary prevention of cardiovascular disease, by investigating the effect of periodontal treatment on the earliest detectable stage of CVD; endothelial dysfunction.MethodsOtherwise healthy periodontitis and non-periodontiti…

An Example: Money

1995

The institution of money, like that of language, or that of the State, has often been seen to be based on some kind of contractual agreement. Aristotle describes the nature of money as follows: Money has become by convention a sort of representative of demand; and that is why it has the name ‘money’ (nomisma) because it exists not by nature but by law (nomos) and it is in our power to change it and make it useless. (Ethica Nicomachea, V.5.II33a) The word nomos is ambiguous: in another translation of Ethica it has been translated as “custom”. This ambiguity reflects a theoretical problem in the classical social theory: money has been seen either as a result of an act of will of the legislato…

Money and the natural rate of interest: structural estimates for the United States and the Euro area

2008

We examine the role of money, allowing for three competing environments: the New Keynesian model with separable utility and static money demand; a non-separable utility variant with habit formation; and a version with adjustment costs for holding real balances. The last two variants imply forward-looking behavior of real money balances, as it is optimal for agents to allow their forecast of future interest rates to affect current portfolio decisions. We distinguish between these specifications by conducting a structural econometric analysis for the U.S. and the euro area. FIML estimates confirm the forward-looking character of money demand. Using these estimates we find that, in response to…

The endoscopic measurement of intravascular pressure and flow in oesophageal varices.

1988

Numerical Simulations of the Hydrodynamics of the Abdominal Aorta Aneurysm (AAA) Using a Smoothed Particle Hydrodynamics Code with Deformable Wall Pr…

2018

We present some preliminary results of the numerical simulations of the hydrodynamic characteristics of an abdominal aorta aneurysm (AAA) patient specific test case. Images of the AAA lumen have been acquired in 10 discrete time-steps through a stabilized cardiac cycle by electrocardiogram-gated computer tomography angiography, and are used to approximate the in vivo, time dependent kinematic fields of the (internal) arterial wall. The flow field is simulated by a Smoothed Particle SPH numerical model, where the kinematics of the boundary of the computational domain (the internal aortic vessel) is the one computed by the above procedure. The outputs of the SPH model, i.e., pressure and flow…

An adaptive control law for robotic manipulator without velocity feedback

2003

In this paper, a new adaptive control law is designed for robotic manipulators, based on the use of reference velocities instead of the actual ones and feedback signals generated from position errors. The law in question is suitable for trajectory tracking and positioning tasks. Its peculiarities are implementation without velocity measurements and estimation, high signal-to-noise ratio in control torques and absence of parameter drift in positioning tasks. Experimental tests are shown with the aim to confirm the validity of the control law and to illustrate its actual effects on the behaviour of the system.

Influence of the channel design on the heat and mass exchange of induction channel furnace

2011

PurposeThe purpose of this paper is to present in‐depth numerical modelling of heat and mass exchange in industrial induction channel furnace (ICF).Design/methodology/approachThe turbulent heat and mass exchange in the melt is calculated using a three‐dimensional (3D) electromagnetic model and a 3D transient large eddy simulation method. The simulation model has been verified by flow velocity and temperature measurements, which were carried out using an industrial sized channel inductor operating with Wood's metal as a low temperature model melt.FindingsThe ICF is well‐established for melting, holding and casting in the metallurgical industry. But there are still open questions regarding th…

Experimental Study of Cross-flow Micro-turbines for Aqueduct Energy Recovery

2014

An important component of the management cost of aqueducts is given by the energy costs. Part of these costs can be recovered by transforming some of the many existing energy dissipations in electric energy by means of economic turbines. In this study an experimental work has been carried out: 1) to test the performance of an economic Cross-Flow turbine which maintains high efficiency within a large range of water discharges, and 2) to validate a new approximated formula relating main inlet velocity to inlet pressure. It is proved that the proposed formula, according to some simplifying assumption, exactly links inlet velocity to inlet pressure according to any possible geometry of the Cros…