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The quantitative relationship between kicking motion and ball behaviour can be easily explained by detecting the impact point and foot posture. In previous studies, the impact point of a kicking foot was difficult to capture using visual tracking. Thus, a virtual surface modelling technique was applied in this study to clarify the differences in the three-dimensional foot speed, impact point and foot posture between straight, curve, and knuckle kicks in soccer, as well as the relationship between the kick motion and ball rotation. An optical three-dimensional motion capture system (VICON) was used to record the kicking motion. The impact points of the straight, curve, and knuckle kicks were found to be centrally located in the instep area, at a lower (more downwards) inside area, and at the medial area between the instep and inside areas of the kicking foot, respectively. Moreover, an impact with a greater 'swing vector deviation angle (relative to the direction from the impact point to the centre of gravity of the ball)' is necessary for ball rotation. The impact point detection method employed in this study can be applied to other ball impact estimations beyond soccer kicks. [ABSTRACT FROM AUTHOR]

Copyright of Acta Materiae Compositae Sinica is the property of Acta Materiea Compositae Sinica Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study investigates the trajectory and spreading of a horizontal circular dense jet flow discharged above the water surface, the flow of which falls into shallow stagnant ambient water. For this purpose, 27 experiments were performed using three diameters, flow rates, and falling heights to investigate jet trajectory. In addition, nine experiments with constant falling height were conducted to study jet spreading. The densimetric Froude number of the jet flow at the nozzle outlet and water surface of the present study ranged from 0.72 to 4.22 and 36.96 to 86.10, respectively. The data pertaining to this study were extracted and analyzed through image processing. The results of the experiments showed that by increasing both the momentum and falling height, the trajectory of the jet flow reached a farther distance from the discharge nozzle. The spreading of the outer boundaries of the dense circular falling jet flow tended to extend downstream of the impact point and had an elliptical motion on the bed. The relationship between radial distance from the impingement point to the outer boundary of flow and time was determined to have a power of 0.67 for flow along the flume and 0.59 for flow along the flume's width.

In the research field of projectile penetration into reinforced concrete, the penetration depth discreteness generally exists in experiments and empirical formulas, and the difference of impact positions is one of the main reasons for this discreteness. To explore the penetration depth discreteness caused by the impact position difference and reveal its mechanism, the finite element models of 3 typical impact positions were established with reference to a published penetration test. The main reasons for the differences in the penetration processes of 3 typical impact positions were compared and analyzed. Based on the numerical calculation results, the expression characterizing the discreteness of penetration depth was summarized. The results show that, the penetration depth of the projectile impacting reinforced concrete is a range value. The expression was preliminarily verified. The main factors causing the penetration depth discreteness are the number of rebars hit by the projectile and the duration of contact with steel bars. This discreteness decreases with the ratio of the projectile diameter to the mesh size of rebars. [ABSTRACT FROM AUTHOR]

Abstract This work presents an alternative method of getting tracking, and the impact point of the actual flight of a rocket, by telemetry data and slant-range device. The tracking and impact point data were obtained from an actual flight path by merging the angular components of a telemetry antenna (Azimuth, and Elevation) and the radial distance information provided by the slant-range device. The position components were analyzed with the telemetry antenna in automatic mode, target tracking, comparing with the tracking results performed by the radar. The result obtained by the composition of the coordinates of the telemetry/slant-range set, it was observed that the point of impact generated by this group had a distance of 237.64 (meters), in relation to the impact generated by the tracking of the radar. Indicating a significant reduction of the search area and can be used as na alternative form of use. It allows you to provide additional location information for payload recovery around the actual point of impact.

Since software packages, which predict the charge motion of single ball in the mineral processing tumbling mills, use the Powell (1991) relationships, the accuracy of these relationships was investigated in this research. The test results indicated that the difference between the impact points for two balls with different materials was lower than 2o. A change in friction coefficient had no significant effect on the ball impact point, whereas in the Powell relationships changing the friction coefficient to 0.4 increased the impact point difference 15o. The friction coefficient in the Powell relationships considers to be more than zero at the point of equilibrium. The impact point difference between the results from the Powell relationships and the relationships that considers static friction coefficient (µs) equal to zero at the point of equilibrium were compared. The results indicated that the difference is negligible when µs is near to zero and is high when µs is more than 0.1.

The rotation of a soccer ball is affected by several factors, such as impact point and foot posture, which are generated by joint torque in the lower limb. This study aimed to investigate joint torque in the lower limb that generates foot posture and swing trajectory, and compare three types of kicks before and after a practice period for participants to learn to control the ball rotation. An optical three-dimensional motion capture system was used to record the kicking motion of the participants. The results indicate that the adduction torque of the hip joint at the moment of impact decreased for curve kicks (from 0.56 to 0.25 Nm/kg) and increased for knuckle kicks (from −0.09 to 0.37 Nm/kg). We considered that the curve and knuckle kicks swing towards the inside (because of their positive values in the post experiment) with hip joint adduction before impact to control ball rotation.

The projectile landing position has to be determined for its recovery and range in the targeting test. In this paper, a global search method based on the velocity variance is proposed. In order to verify the applicability of this method, simulation analysis within the scope of four million square meters has been conducted in the same array structure of the commonly used linear positioning method, and MATLAB was used to compare and analyze the two methods. The compared simulation results show that the global search method based on the speed of variance has high positioning accuracy and stability, which can meet the needs of impact point location. [ABSTRACT FROM AUTHOR]

Copyright of Telecommunication Engineering is the property of Telecommunication Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Ballistics / Dandao Xuebao is the property of Journal of Ballistics Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The aim of this paper is to analyse and compare injuries and injury sources in pedestrian and bicyclist non-fatal real-life frontal passengercar crashes, considering in what way pedestrian injury mitigation systems also might be adequate for bicyclists. Data from 203 non-fatal vehicle-to-pedestrian and vehicle-to-bicyclist crashes from 1997 through 2006 in a city in northern Sweden were analysed by use of the hospitals injury data base in addition to interviews with the injured. In vehicle-to-pedestrian crashes (n = 103) head and neck injuries were in general due to hitting the windscreen frame, while in vehicle-to-bicycle crashes (n = 100) head and neck injuries were typically sustained by ground impact. Abdominal, pelvic and thoracic injuries in pedestrians and thoracic injuries in bicyclists were in general caused by impacting the bonnet. In vehicle-to-pedestrian crashes, energy reducing airbags at critical impact points with low yielding ability on the car, as the bonnet and the windscreen frame, might reduce injuries. As vehicle-to-bicyclist crashes occurred mostly in good lighting conditions and visibility and the ground impact causing almost four times as many injuries as an impact to the different regions of the car, crash avoidance systems as well as separating bicyclists from motor traffic, may contribute to mitigate these injuries. [ABSTRACT FROM AUTHOR]

The kick skill and its analysis are important in Soccer. To detect impact point by using virtual impact model is aim of this study. The virtual impact model was made as a surface composed of virtual markers. As the result, mean coordinate values of impact point were below; straight (Lateral: −24.0 ± 5.6 mm, Horizontal: 152.7 ± 8.4 mm, Vertical: 52.3 ± 4.0 mm), curve (Lateral: −35.6 ± 4.8 mm, Horizontal: 151.6 ± 13.7 mm, Vertical: 47.5 ± 5.2 mm), knuckle (Lateral: −33.3 ± 9.0 mm, Horizontal: 140.8 ± 10.7 mm, Vertical: 52.1 ± 2.7 mm). According to comparison of coordinate value of each trial, mean point of straight was near the center line of foot on instep, mean point of curve was located on inside of foot, mean point of knuckle was near the foot joint. We revealed difference of impact point and showed trajectory of impact point.

Direct observation of the charge shape and its motion in industrial mills is not possible, it is then customary to use transparent end, small-scale mills (i.e., model mills) to determine the charge trajectory directly by visualization methods. Because of a short length of the model mills, the end-wall effects could introduce a significant bias on the observed charge trajectories and shape. In this research, the end-wall effect was investigated by gradually increasing the model mill length and analysing the charge trajectory and shape variation at given operating conditions (i.e., ball filling, mill speed, liner type). The special design of the model mill with the diameter of 100 cm made it possible to increase the mill length in steps of 3.6 cm up to 21.6 cm. Four types of liners, five steel ball fillings (10, 15, 20, 25, 30% v / v ) and three mill speeds (55, 70, 85% of critical speed) were tested. The results indicated that when the mill length was below 10.8 cm the end-walls prevented the charge from free falling. This resulted in lower impact point angles and lower power draws compared with the case of no end-wall effect. When the same experiments were performed using an iron ore instead of balls with the same size range, the impact of end-wall effect was more pronounced. For a mill length of 3.6 cm, an increase of 30% in the speed (from 55 to 85%) with the iron ore charge, the torque decreased by 41% (from 3.7 to 2.2 kgf·m) when mill filling was 30%. At the same operating conditions, when steel balls were used the torque decreased only by 19% (from 9 to 7.2 kgf·m). Three-dimensional DEM simulations also resulted in similar conclusions. [ABSTRACT FROM AUTHOR]

Highlights: [•] Correcting charge shape and single ball trajectory considering charge effect. [•] Increasing liner lifter face angle from 7° to 30°. [•] Converting AG to SAG milling caused 31% increase in throughput. [ABSTRACT FROM AUTHOR]

The aims of this study were to examine whether batters hit stationary balls at the time of peak speed of the bat head and whether the impact occurs at the lowest point of the bat trajectory. Eight university baseball players hit three balls, each hung with a string; each ball was made of a different material and was different in weight. Bat movement was captured by four 240-Hz infrared cameras and analysed three-dimensionally. Time for peak speed of the bat head varied according to the conditions. When stationary balls of standard weight were used, the bat head was at maximum speed at impact with the ball; then, it decelerated drastically owing to the impact. In contrast, maximum speed was obtained after impact when lightweight stationary balls were used. The time-speed profile of the bat head before impact in the lightweight ball condition was identical with that in the standard weight ball condition. Regardless of conditions, the timing of the lowest point of the bat head was nearly identical for each batter and most participants hit the stationary balls at about the lowest point of the bat trajectory [ABSTRACT FROM AUTHOR]

Bicyclist and pedestrian injuries in collisions with vehicles in Japan were investigated based on national and in-depth accident data analyses and mathematical simulations. In an impact with a bonnet-type vehicle, a bicyclist slides over the bonnet of the vehicle, behavior that is not observed for pedestrians. As a result, the bicyclist’s head tends to strike a bonnet-type vehicle at a more rearward location in comparison with pedestrians. The first contact position of a bicycle with a vehicle, the vehicle front-end geometry and the bicycle velocity affect whether the bicyclist’s head strikes the vehicle or not. Due to the bent-knee posture of a bicyclist’s legs, the types of leg injuries sustained by bicyclists and their causes differ from those seen for pedestrians. Component test procedures have been proposed for evaluating pedestrian safety, but some modifications of the head impact area and angle are necessary when applying these methods to bicyclists. [Copyright &y& Elsevier]

A numerical model is presented which describes the strain level build-up in yarns due to multiple strain wave reflections from yarn crossover intersections in a woven fabric subject to ballistic impact. Crossing yarns present barriers from which strain waves are partially reflected. The maximum yarn strain occurs at the point of impact and decays with distance along the yarn away from this point. The rapidity of decay is governed by the crossover reflection coefficient. Using observations of the deformation cone size of ballistically impacted fabric panels, it is concluded that the reflection coef ficient is small (approximately 0.01). The strain increases with time at different rates for different reflection coefficients until failure at the impact point. Extensions of this model to other fibrous structures are discussed. [ABSTRACT FROM PUBLISHER]