scholarly journals Modelling and simulation of functioning of the GSh-23 aviation autocannon mechanisms

2021 ◽  
Author(s):  
Michał Jasztal
Keyword(s):  
Simulation Model ◽  
Multibody Systems ◽  
High Speed ◽  
Modelling And Simulation ◽  
Belt Drive ◽  
High Speed Camera ◽  
Kinematic Parameters ◽  
Piston Mechanism ◽  
Time Courses ◽  
Solid Edge

Article presents the simulation model and the study of the basic mechanisms of the GSh-23 aviation autocannon. The research made use of Solid Edge ST9 software and the multibody systems method implemented in it. Simulation of functioning cannon mechanisms was carried out for two variants of forcing a piston mechanism movement by the gunpowder gases. The results obtained are time courses of a bolt and a cartridge belt drive mechanism elements movement. Assumed variants of a piston mechanism movement and elaborated simulation model will be verified in the next (planned) stage of studies basing on the results of the measurements of the experimental kinematic parameters utilising high-speed camera (Phantom) and TEMA software.

NEUROMECHANICAL STRATEGY IN VISUALLY IMPAIRED STUDENT DURING DOWNWARD STEPPING

2005 ◽  
Vol 05 (02) ◽  
pp. 261-265 ◽  
Author(s):  
YUN-CHING HUANG ◽  
WEN-JIE HUANG ◽  
FENG-JEN TSAI ◽  
YU LIU
Keyword(s):  
Visually Impaired ◽  
High Speed ◽  
Reaction Force ◽  
Peak Performance ◽  
Emg Activity ◽  
High Speed Camera ◽  
Normal Vision ◽  
Kinematic Parameters ◽  
Neuromuscular Activation ◽  
Visually Impaired Students

The purpose of the present study was to evaluate leg muscular regulation and neuromuscular activation by investigating the stiffness and EMG amplitude between normal vision students and visually impaired students. Ten normal vision (age: 24.3 ± 2 years; 171.5 ± 4.6; mass: 65.9 ± 8.0) and 10 visually impaired students (age: 23.2 ± 2.4 years; 163.4 ± 9.6; mass: 62.8 ± 15.0) served as subjects. An AMTI force platform (1200 Hz) and a Peak Performance high speed camera (60 Hz) were used synchronously to record the ground reaction force, the kinematic parameters and EMG signals of lower extremity during the subjects stepped down from height 20, 30 and 40 cm. After treating the data and discussion, the conclusions were obtained. The regulation of neuromusclar system of the impaired is less efficient compared to the normal one because of softer stiffness and lower EMG activity.

Kinematic analysis of new and used reciprocating endodontic motors in 2 different modes

2017 ◽  
Vol 41 (1) ◽  
pp. 17-22 ◽  
Author(s):  
Özgür Irmak ◽  
Ekim O. Orhan
Keyword(s):  
Statistical Analysis ◽  
Kinematic Analysis ◽  
High Speed ◽  
Angle Measurement ◽  
High Speed Camera ◽  
Reciprocating Motion ◽  
Kinematic Parameters ◽  
Full Rotation ◽  
Number Of Cycles ◽  
One Way Anova

Purpose: The actual reciprocating angles of endodontic motors might differ from the manufacturers’ set values. This study analyzed the effect of clinical usage on the kinematics of reciprocating endodontic motors with 2 different reciprocal modes. Methods: 1 new and 3 used reciprocating endodontic motors (X-Smart Plus, Dentsply Maillefer) with 2 different reciprocating modes, WaveOne mode (W-mode) or Reciproc mode (R-mode), were analyzed. An angle measurement disc was inserted into a contra-angle. Reciprocating motions were recorded with a high-speed camera at 1,200 fps and analyzed on a computer. The following kinematic parameters were calculated: duration of each reciprocating motion, engaging and disengaging angles, cycle rotational speeds, engaging and disengaging rotational speeds, net cycle angle, total cycle angle, and number of cycles to complete full rotation. One-way ANOVA and Kruskal-Wallis test followed by multiple comparison tests were used for statistical analysis (p = 0.05). Results: In W-mode, the actual engaging angles of all used and new motors were different from the manufacturer’s set values (p<0.0001), whereas there was no difference between actual engaging angles among the motors (p>0.05). In R-mode, the actual engaging angles of all used and new motors were similar to the manufacturers’ set values (p>0.05). There was no difference between the actual engaging angles among motors (p>0.05). Both the W-mode and R-mode showed statistically different values of actual disengaging angles for all used and new motors when compared with the manufacturers’ set value (p<0.0001). Conclusions: This study confirmed that the actual kinematics of reciprocating endodontic motors differ from the manufacturers’ set values. Some kinematic parameters were influenced by the clinical usage of the motors.

Articulatory Behavior Pre and Post Full-Mouth Tooth Extraction and Alveoloplasty

1980 ◽  
Vol 23 (3) ◽  
pp. 630-645 ◽  
Author(s):  
Gerald Zimmermann ◽  
J.A. Scott Kelso ◽  
Larry Lander
Keyword(s):  
Control Subject ◽  
High Speed ◽  
Tooth Extraction ◽  
Kinematic Parameters ◽  
Experimental Conditions ◽  
Mean Values ◽  
Articulatory Movements ◽  
The Mean ◽  
Experimental Subjects ◽  
Normal Speech

High speed cinefluorography was used to track articulatory movements preceding and following full-mouth tooth extraction and alveoloplasty in two subjects. Films also were made of a control subject on two separate days. The purpose of the study was to determine the effects of dramatically altering the structural dimensions of the oral cavity on the kinematic parameters of speech. The results showed that the experimental subjects performed differently pre and postoperatively though the changes were in different directions for the two subjects. Differences in both means and variabilities of kinematic parameters were larger between days for the experimental (operated) subjects than for the control subject. The results for the Control subject also showed significant differences in the mean values of kinematic variables between days though these day-to-day differences could not account for the effects found pre- and postoperatively. The results of the kinematic analysis, particularly the finding that transition time was most stable over the experimental conditions for the operated subjects, are used to speculate about the coordination of normal speech.

scholarly journals Tracking by Deblatting

2021 ◽  
Author(s):  
Denys Rozumnyi ◽  
Jan Kotera ◽  
Filip Šroubek ◽  
Jiří Matas
Keyword(s):  
High Speed ◽  
High Performance ◽  
Motion Blur ◽  
Velocity Estimation ◽  
High Speed Camera ◽  
Trajectory Function ◽  
Novel Approach ◽  
Blind Deblurring ◽  
Object Trajectories ◽  
Complex Trajectories

AbstractObjects moving at high speed along complex trajectories often appear in videos, especially videos of sports. Such objects travel a considerable distance during exposure time of a single frame, and therefore, their position in the frame is not well defined. They appear as semi-transparent streaks due to the motion blur and cannot be reliably tracked by general trackers. We propose a novel approach called Tracking by Deblatting based on the observation that motion blur is directly related to the intra-frame trajectory of an object. Blur is estimated by solving two intertwined inverse problems, blind deblurring and image matting, which we call deblatting. By postprocessing, non-causal Tracking by Deblatting estimates continuous, complete, and accurate object trajectories for the whole sequence. Tracked objects are precisely localized with higher temporal resolution than by conventional trackers. Energy minimization by dynamic programming is used to detect abrupt changes of motion, called bounces. High-order polynomials are then fitted to smooth trajectory segments between bounces. The output is a continuous trajectory function that assigns location for every real-valued time stamp from zero to the number of frames. The proposed algorithm was evaluated on a newly created dataset of videos from a high-speed camera using a novel Trajectory-IoU metric that generalizes the traditional Intersection over Union and measures the accuracy of the intra-frame trajectory. The proposed method outperforms the baselines both in recall and trajectory accuracy. Additionally, we show that from the trajectory function precise physical calculations are possible, such as radius, gravity, and sub-frame object velocity. Velocity estimation is compared to the high-speed camera measurements and radars. Results show high performance of the proposed method in terms of Trajectory-IoU, recall, and velocity estimation.

scholarly journals Influence of tool edge form factor and cutting parameters on milling performance

2021 ◽  
Vol 13 (4) ◽  
pp. 168781402110090
Author(s):  
Xuefeng Zhao ◽  
Hao Qin ◽  
Zhiguo Feng
Keyword(s):  
Form Factor ◽  
Simulation Model ◽  
Cutting Force ◽  
Surface Quality ◽  
High Speed ◽  
Orthogonal Cutting ◽  
Cutting Temperature ◽  
Tool Edge ◽  
Drag Finishing ◽  
Edge Preparation

Tool edge preparation can improve the tool life, as well as cutting performance and machined surface quality, meeting the requirements of high-speed and high-efficiency cutting. In general, prepared tool edges could be divided into symmetric or asymmetric edges. In the present study, the cemented carbide tools were initially edge prepared through drag finishing. The simulation model of the carbide cemented tool milling steel was established through Deform software. Effects of edge form factor, spindle speed, feed per tooth, axial, and radial cutting depth on the cutting force, the tool wear, the cutting temperature, and the surface quality were investigated through the orthogonal cutting simulation. The simulated cutting force results were compared to the results obtained from the orthogonal milling experiment through the dynamometer Kistler, which verified the simulation model correctness. The obtained results provided a basis for edge preparation effect along with high-speed and high effective cutting machining comprehension.

Influence of Main Swirler Vane Angle on the Ignition Performance of TeLESS-II Combustor

2016 ◽  
Vol 139 (1) ◽  
Author(s):  
Bo Wang ◽  
Chi Zhang ◽  
Yuzhen Lin ◽  
Xin Hui ◽  
Jibao Li
Keyword(s):  
High Speed ◽  
Inlet Temperature ◽  
Main Stage ◽  
Ignition Process ◽  
High Speed Camera ◽  
Fuel Distribution ◽  
Fuel Droplets ◽  
Planar Laser ◽  
Cfd Method ◽  
Vane Angle

In order to balance the low emission and wide stabilization for lean premixed prevaporized (LPP) combustion, the centrally staged layout is preferred in advanced aero-engine combustors. However, compared with the conventional combustor, it is more difficult for the centrally staged combustor to light up as the main stage air layer will prevent the pilot fuel droplets arriving at igniter tip. The goal of the present paper is to study the effect of the main stage air on the ignition of the centrally staged combustor. Two cases of the main swirler vane angle of the TeLESS-II combustor, 20 deg and 30 deg are researched. The ignition results at room inlet temperature and pressure show that the ignition performance of the 30 deg vane angle case is better than that of the 20 deg vane angle case. High-speed camera, planar laser induced fluorescence (PLIF), and computational fluids dynamics (CFD) are used to better understand the ignition results. The high-speed camera has recorded the ignition process, indicated that an initial kernel forms just adjacent the liner wall after the igniter is turned on, the kernel propagates along the radial direction to the combustor center and begins to grow into a big flame, and then it spreads to the exit of the pilot stage, and eventually stabilizes the flame. CFD of the cold flow field coupled with spray field is conducted. A verification of the CFD method has been applied with PLIF measurement, and the simulation results can qualitatively represent the experimental data in terms of fuel distribution. The CFD results show that the radial dimensions of the primary recirculation zone of the two cases are very similar, and the dominant cause of the different ignition results is the vapor distribution of the fuel. The concentration of kerosene vapor of the 30 deg vane angle case is much larger than that of the 20 deg vane angle case close to the igniter tip and along the propagation route of the kernel, therefore, the 30 deg vane angle case has a better ignition performance. For the consideration of the ignition performance, a larger main swirler vane angle of 30 deg is suggested for the better fuel distribution when designing a centrally staged combustor.

Sign in / Sign up

Export Citation Format

Share Document