Maximum Displacement Velocity Research Articles

Study of dielectric particles motion in traveling and standing electrostatic waves using particle tracking velocimetry

The accumulation of dust and airborne particles on solar panels drastically reduces the quality of the produced energy. A promising solution consists of using traveling and standing electric waves to clean the solar panels or to avoid particle deposition on their surface. This work aims to better understand the motion mechanisms of micrometer-sized particles under the effect of electrostatic traveling and standing waves, by characterizing their displacement velocity using particle tracking velocimetry (PTV). In this experimental work, the particles motion is recorded using a high speed camera. Then, a PTV based post-processing has been carried out to get velocity vectors of individual particles based on Lagrangian approach. The velocity profiles in both and axis have been studied as a function of voltage, frequency, and particle size. The results show that the particles pass through levitation, falling, and acceleration phases during their motion. Increasing the voltage leads to a higher velocity. The small particles are more likely to be trapped in the electric potential wave because they are less affected by gravitational and drag forces. That makes their velocity higher than the bigger ones. The average velocity of particles goes through a maximum as a function of frequency in the forward direction of the traveling wave conveyor, and in both directions of the standing wave conveyor. The maximum displacement velocity in the traveling wave conveyor is higher than that obtained in standing wave one.

Study on the mitral valve geometry of the healthy subjects assessed by real-time three-dimensional transthoracic echocardiography and real-time three-dimensional transesophageal echocardiography

Objective To assess the correlation and agreement of the mitral valve geometry parameters obtained by real-time three-dimensional transthoracic echocardiography (RT-3D-TTE) and real-time three-dimensional transesophageal echocardiography (RT-3D-TEE). Methods RT-3D-TTE and RT-3D-TEE were performed on 29 healthy volunteers under conscious state and general anesthesia respectively. The mid-systole mitral valve parameters were analyzed by TomTec Imaging Systems. The repeatability test of the mitral valve parameters obtained by RT-3D-TTE was performed. The correlation and agreement of the mitral valve parameters obtained by RT-3D-TTE and RT-3D-TEE were assessed,and then the differences of mitral valve parameters between the two methods were compared. The study was approved by the Shanxi Dayi Hospital Ethics Committee (Approval no.YXLL-2015-040). Results ①The mitral valve parameters obtained by RT-3D-TTE showed excellent intra- and interobserver reproducibility,in intra-observer and inter-observer with ICC>0.8 for all the parameters,and the Bland-Altman plots displayed the average differences of anterior-posterior (AP),anterolateral-posteromedial (ALPM),annular circumference (AC),three-dimensional annular area (AA3D) for intra- and interobserver were 0.009±0.11,-0.008±0.10,-0.036±0.32,0.030±0.36 in intra-observer and -0.018±0.09,0.087±0.20,-0.037±0.44,-0.016±0.62 in inter-observers,respectively. ②There were close correlations (r=0.566-0.870,P 0.05). The rest of parameters including ALPM,sphericity (SPI),commissural diameter (CD),AC,AA3D,nonplanarity angle (NPA),tenting height (TH),maximum annular displacement (ADmax) and maximum annular displacement velocity (ADVmax) had significant differences (P<0.05). Conclusions The mitral valve parameters obtained by RT-3D-TTE are highly reproducible and similar to those obtained by RT-3D-TEE,and the two methods have close correlations and good agreement. Therefore,RT-3D-TTE has higher potential clinical application value in the evaluation of mitral valve geometry. Key words: Echocardiography,real-time three-dimensional; Mitral valve

Gschliefgraben mudslide (Austria): hazard evaluation and risk mitigation

A rock slide on top of the clayey–silty–sandy–pebbly masses in the Gschliefgraben (Upper Austria province, Lake Traunsee) having occurred in 2006, together with the humid autumn of 2007, triggered a mudslide comprising a volume up to 4 million m³ and moving with a maximum displacement velocity of 5 m/day during the winter of 2007–2008. The possible damage was estimated up to 60 million € due to the possible destruction of houses and of a road to a settlement with intense tourism. The movement front ran ahead in the creek bed. Therefore, it was assumed that water played an important role. Inclinometer measurements showed that a less permeable layer was sliding on a thin, more permeable layer. During the last centuries, mudslides had already pushed farms into the lake, as reported by chronicles. Thus, the inhabitants of 46 houses had to be evacuated for safety reasons. They could return to their homes after displacement velocities had decreased. It was decided (a) to prevent soaking of water into the uppermost, less permeable layer by transversal drainages, (b) to lower the pore water pressures by longitudinal trenches filled with blocky material, (c) to pump water out of the more permeable layer by well drillings upslope of the houses in order to create a stable block below the houses and (d) to remove material thrust over the stable blocks in order to avoid damage to the houses. These mitigation measures costing 11.5 million € led to a deceleration of the process to displacement velocities of some cm/year up to now. The houses and the road were not damaged.

A cladistic and comparative analysis of kinematic components of the fast-start of fishes, with a note on body size constraints

The fast-start is an ecologically relevant behavior pattern in fishes. The present article analyses the distribution of five continuous kinematic traits (latency for response initiation, time to maximum angular velocity, time to maximum displacement velocity, maximum angular velocity, and maximum displacement velocity) in eight of the eleven species described in Eaton (66:65-81, 1977). Phylogenetic generalized least square estimation of ancestor states demonstrated evolutionary changes in maximum angular velocity and maximum displacement velocity, consistent with species differences in the same variables. These changes in maximum velocity are also correlated (phylogenetically independent contrasts) with the mean body sizes of all species, pointing to the possibility that body size was an evolutionary constraint on maximum velocities. The conservation of the other traits suggest that they are mainly constrained by neural control, and a trade-off between neural and body size-constraints is proposed ex hypothesi.