Peaks In Velocity Profiles Research Articles

Upper limb evaluation with robotic exoskeleton. Normative values for indices of accuracy, speed and smoothness

Robotic rehabilitation devices for upper limb function (ULF) provide global indicators of a patient's ability, but the temporal evolution of motion related to motor control is disregarded. To determine normative values for indices of accuracy, speed and smoothness in the evaluation of upper limb function. Twenty-five healthy individuals performed the Armeo®Spring device "Vertical Capture" task. Custom stand-alone software was developed to provide the following indices: global Hand Path Ratio (HPR), local HPR in the target area (locHPR), vertical and horizontal overshoot (vertOS, horOS), maximum and mean velocity (maxVel, meanVel), mean/maximum velocity, number of peaks in velocity profiles (NVelPeaks) and normalized jerk (NormJerk). The dependence of indices on task characteristics was analyzed by an ANCOVA test. Indices inner relationships were assessed by a correlation and a factor analysis. Normative values were then provided. 4,268 single reaching movements were analyzed. Four indices were not affected by movement direction. Indices were minimally influenced by the difficulty level. Based upon correlation and factor analysis indices and can be grouped into three assessment fields, dealing with precision, velocity and smoothness. We have developed a tool to assess ULF in dynamic condition. Normative values were obtained to be used as references in assessing patients.

MHD Convection of an Electrically Conductive Fluid with Variable Thermal Conductivity

The effect of temperature-dependent thermal conductivity on the magneto-convection in a low Prandtl number liquid is investigated numerically. The liquid is contained in a closed square cavity with isothermal vertical walls kept at different temperatures. The top and bottom walls are assumed to be insulated. To solve the governing non-linear differential equations (mass, momentum and energy) a finite volume code based on SIMPLER algorithm is utilized. The results for different Rayleigh numbers (Ra), Hartmann numbers (Ha) and temperature coefficient of thermal conductivity (η) are presented in form of streamlines, isotherms and Nusselt number. It is found that the heat transfer decreases appreciably across the cavity with a decrease in thermal conductivity. It is observed that at low Hartmann number (Ha=30) the thermal boundary layer is formed near the side walls and as η increases the thickness of these boundaries decreases. Also it is found that as non-dimensional thermal conductivity increases the peak of velocity profile increases; however, this phenomenon is very weak at high Hartmann number.

874 The assessment of right and left ventriclar assynchrony in patients with chronic pulmonary thromboembolism prior and post surgical trombendartherectomy

Background: The pressure overload of the right ventricle (RV) in patients with pulmonary hypertension in the course of chronic pulmonary thromboembolism (CTEPH) alters the mechanical properties of the RV and may result in dyssynchroneous work of both ventricles. Aim: The assessment of changes in synchrony of both ventricles prior and post thrombendartherectomy. Methods: The study group consisted of 7 patients (mean age 50±13 years, 3 male, 4 female) with a diagnosis of CTEPH confirmed by angiography, who had had a surgical thrombendartherectomy. The intraventricular conduction disturbances were not detected neither before nor post operation. Follow up data were collected 1 month post operation: RV diastolic dimension, PV-AcT, RVEF and time form the beginning of QRS till the onset and peak of velocity profile of RV free wall by TDI (respectively RVwall-time to onset, RVwall-time to peak), interventricular septum (IVS-time to onset, IVS-time to peak) and lateral LV wall (LVlat-time to onset, LVlat-time to peak). The intraventricular delay for RV and LV (LVlat-IVS delay; RVwall-IVS delay) and interventricular delay (LVlat-RVwall delay) were calculated. Results: After the endartherectomy NYHA class has changed from 3.2±0.7 to 1.4±0.5, p<0.001; mean pulmonary artery pressure from 51.3±11.7 vs 25±3 mm Hg, p<0.01; total pulmonary resistance from 890±413 to 202±64 dyn/ /cm/s-5, p<0.01. Interand intraventricular delays are shown in the table.

Avoiding spurious velocity overshoots in hydrodynamic simulations of deep submicron devices by a physical modelling of heat transport

We show that spurious peaks in velocity profiles emerging from hydrodynamic simulators of submicron n+nn+ Si structures are washed out by using a field-dependent thermal conductivity calculated within a correlation function formalism.