Journal articles: 'Ball launcher'

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Tomac, Mike. "The “holey” ball launcher." Physics Teacher 38, no. 2 (February 2000): 75. http://dx.doi.org/10.1119/1.880458.

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Ivashtenko, Oryna, Polina Kofman, Oleksiy Golubov, and Zakhar Maizelis. "Origami launcher." Emergent Scientist 3 (2019): 5. http://dx.doi.org/10.1051/emsci/2019004.

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The article studies the elastic and locomotive properties of Miura-ori-type paper origami. The mechanics of a single paper crease is studied experimentally, and its non-elastic properties turn out to be crucial. The entire origami construction is then described as a collection of individual creases, its capability to launch small objects is evaluated, and the equation of motion is found. Thus, the height of the launched ball is studied theoretically and experimentally as a function of governing parameters.

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Yamagami, Hiroshi, Hidemitsu Tanaka, Yoshiaki Okui, and Hajime Yamada. "Flying Velocity Characteristics of a Steel Ball by Means of Solenoid Type Electromagnetic Launcher." IEEJ Transactions on Industry Applications 112, no. 12 (1992): 1214–19. http://dx.doi.org/10.1541/ieejias.112.1214.

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Gies, Valentin, Thierry Soriano, Sebastian Marzetti, Valentin Barchasz, Herve Barthelemy, Herve Glotin, and Vincent Hugel. "Optimisation of Energy Transfer in Reluctance Coil Guns: Application to Soccer Ball Launchers." Applied Sciences 10, no. 9 (April 30, 2020): 3137. http://dx.doi.org/10.3390/app10093137.

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Reluctance coil guns are electromagnetic launchers having a good ratio of energy transmitted to actuator volume, making them a good choice for propelling objects with a limited actuator space. In this paper, we focus on an application, which is launching real size soccer balls with a size constrained robot. As the size of the actuator cannot be increased, kicking strength can only be improved by enhancing electrical to mechanical energy conversion, compared to existing systems. For this, we propose to modify its inner structure, splitting the coil and the energy storage capacitor into several ones, and triggering the coils successively for propagating the magnetic force in order to improve efficiency. This article first presents a model of reluctance electromagnetic coil guns using a coupled electromagnetic, electrical and mechanical models. Four different coil gun structures are then simulated, concluding that splitting the kicking coil into two half size ones is the best trade-off for optimizing energy transfer, while maintaining an acceptable system complexity and controllability. This optimization results in robust enhancement and leads to an increase by 104 % of the energy conversion compared to a reference launcher used. This result has been validated experimentally on our RoboCup robots. This paper also proves that splitting the coil into a higher number of coils is not an interesting trade-off. Beyond results on the chosen case study, this paper presents an optimization technique based on mixed mechanic, electric and electromagnetic modelling that can be applied to any reluctance coil gun.

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Wang, Bo, Yu Wang, and Jin Lin Huang. "A New Type of Pig Handling Trolley." Applied Mechanics and Materials 84-85 (August 2011): 347–51. http://dx.doi.org/10.4028/www.scientific.net/amm.84-85.347.

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The Pig is an important tool during the process of oil-gas pipeline’s production, replacement, daily operation and management. Its outer diameter is 2% to 5% larger than the inner diameter of pipelines. It stays a clamping state in the pipelines. The fluid pressure difference before and after the Pig push it from the beginning to the end of the pipelines in order to clear all kinds of impurities in the pipelines and detect the internal and external wall corrosion status of the pipelines or achieve other goals. But during the cleaning-up operation, it is difficult for the Pig to get in and out of the pipelines because of its heavy weight. So a Pig and Pigging ball handling trolley is designed in this paper to push and pull the Pig or Pigging ball to get in and out of the Pig launcher & receiver device. This handling trolley will mechanize the Pigging operations, reduce the labor intensity and improve the work efficiency.

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Moreno, Francisco J., Vicente Luis, Francisco Salgado, Juan A. García, and Raúl Reina. "Visual Behavior and Perception of Trajectories of Moving Objects with Visual Occlusion." Perceptual and Motor Skills 101, no. 1 (August 2005): 13–20. http://dx.doi.org/10.2466/pms.101.1.13-20.

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Experienced athletes in sports with moving objects have shown greater skill when using visual information to anticipate the direction of a moving object than nonexperienced athletes of those sports. Studies have shown that expert athletes are more effective than novices in occlusion situations in the first stages of the sports sequence. In this study, 12 athletes with different competitive experience in sports with moving objects viewed a sequence of tennis ball launches with and without visual occlusion, launched by a ball-shooting machine toward different areas with respect to the participant's position. The relation among visual behavior, occlusion time, and the precision of the task is reviewed. The spot where the balls bounced was analysed by a digital camera and visual behavior by an Eye Tracking System. Analysis showed that the nonexperienced athletes made significantly more errors and were more variable in visual occlusion conditions. Participants had a stable visual search strategy.

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Berdeni, Y., A. Champneys, and R. Szalai. "The two-ball bounce problem." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 471, no. 2179 (July 2015): 20150286. http://dx.doi.org/10.1098/rspa.2015.0286.

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A popular classroom demonstration is revisited in which a light ball and a much larger heavier ball are vertically aligned and dropped together onto a hard surface. Careful experimental data obtained using a high-speed camera is compared to a lumped-mass Newtonian restitution model. Good macroscopic agreement is found, provided there is sufficient separation between the two balls as they are dropped. An alternative continuum model based on elastic membrane theory is developed to explain the limit in which the balls are initially touching. The model assumes the lower ball deforms to a truncated sphere upon its impact with the floor, exciting an elastic wave which subsequently launches the upper ball like a particle on a trampoline, before the lower ball leaves the ground. A favourable comparison with experimental data is found for the case of negligible initial separation between the balls.

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Nakashima, Hirotaka, Gen Horiuchi, and Shinji Sakurai. "Standard of the Initial Ball Velocity for a Fly Ball in Baseball Hitting." Proceedings 49, no. 1 (June 15, 2020): 137. http://dx.doi.org/10.3390/proceedings2020049137.

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This study aimed to determine the minimum required initial velocity to hit a fly ball toward the same field (left-field for right-handed batters), center field, and opposite field (right field for right-handed batters). Six baseball players hit fastballs launched by a pitching machine. The movements of the balls before and after bat-to-ball impact were recorded using two high-speed video cameras. The flight distance was determined using a measuring tape. Seventy-nine trials were analyzed, and the minimum required initial velocities of batted balls were quantified to hit balls 60, 70, 80, 90, 100, 110, and 120 m in each direction through regression analysis. As a result, to hit a ball 120 m, initial velocities of 43.0, 43.9, and 46.0 m/s were required for the same field, center field, and opposite field, respectively. The result provides a useful index for batters to hit a fly ball in each of the directions.

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Pinto, Gustavo, Andresa Baptista, Francisco Silva, Jacobo Porteiro, José Míguez, and Ricardo Alexandre. "Study on the Influence of the Ball Material on Abrasive Particles’ Dynamics in Ball-Cratering Thin Coatings Wear Tests." Materials 14, no. 3 (February 1, 2021): 668. http://dx.doi.org/10.3390/ma14030668.

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Micro-abrasion remains a test configuration hugely used, mainly for thin coatings. Several studies have been carried out investigating the parameters around this configuration. Recently, a new study was launched studying the behavior of different ball materials in abrasive particles’ dynamics in the contact area. This study intends to extend that study, investigating new ball materials never used so far in this test configuration. Thus, commercial balls of American Iron and Steel Institute (AISI) 52100 steel, Stainless Steel (SS) (AISI) 304 steel and Polytetrafluoroethylene (PTFE) were used under different test conditions and abrasive particles, using always the same coating for reference. Craters generated on the coated samples’ surface and tracks on the balls’ surface were carefully observed by Scanning Electron Microscopy (SEM) and 3D microscopy in order to understand the abrasive particles’ dynamics. As a softer material, more abrasive particles were entrapped on the PTFE ball’s surface, generating grooving wear on the samples. SS AISI 304 balls, being softer than the abrasive particles (diamond), also allowed particle entrapment, originating from grooving wear. AISI 52100 steel balls presented particle dynamics that are already known. Thus, this study extends the knowledge already existing, allowing to better select the ball material to be used in ball-cratering tests.

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Allen, Mitchell. "The Autoethnographer’s Ball, 2040." Journal of Autoethnography 1, no. 1 (2020): 9–15. http://dx.doi.org/10.1525/joae.2020.1.1.9.

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Patricia A. and Peter Adler’s 1999 article on The Ethnographer’s Ball, a hypothetical geography of the community of ethnographers, launched this exercise in futurist speculation. What will happen to autoethnography in the future? What historical trajectory will it take? The adherents of autoethnography—now in its ascendance as a research movement, particularly with the launch of its new journal—will likely follow one or another trajectory that previous intellectual communities have traced. This paper projects five potential scenarios for the future of autoethnography twenty years from now: from universal acceptance, to a narrowly defined community, to being hijacked by a future intellectual movement, to institutionalization within the academy, to complete disappearance. It compares these scenarios to the fates of other scholarly communities such as symbolic interaction, world-systems analysis, and social impact assessment.

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Carlsson, Magnus, Johnny Nilsson, John Hellström, Fredrik Tinmark, and Tomas Carlsson. "The effect of ball temperature on ball speed and carry distance in golf drives." Proceedings of the Institution of Mechanical Engineers, Part P: Journal of Sports Engineering and Technology 233, no. 2 (November 28, 2018): 186–92. http://dx.doi.org/10.1177/1754337118812618.

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The purpose of this study was to investigate the effect of ball temperature on impact ball speed and carry distance during golf drives in a blind randomized test design. The balls were exposed to a temperature-controlled environment (4 °C, 18 °C, 32 °C, and 46 °C) for 24 h prior to the test and each temperature group consisted of 30 balls. The 120 drives were performed by an elite male golfer (handicap: 0.0) in an indoor driving range. All drives were measured by a Doppler-radar system to determine the club-head speed, launch angle, spin rate, ball speed, and carry distance. Differences between the groups were investigated using a one-way analysis of variance. The results indicated that ball-speed and carry-distance differences occurred within the four groups ( p < 0.001 and p < 0.01, respectively). The post hoc analyses showed that the ball temperatures of 18 °C and 32 °C had greater ball speeds and carry distances than balls at 4 °C and 46 °C (all p < 0.05). The intervals for the between-group differences were 0.6–0.7 m s−1 and 2.9–3.9 m for ball speed and carry distance, respectively. Hence, the results showed that ball temperature influences both the ball speed and the carry distance. Based on the findings in this study, standardization of ball temperature should be factored into governing body regulation tests for golf equipment.

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Goff, John Eric, Sungchan Hong, and Takeshi Asai. "Aerodynamic and surface comparisons between Telstar 18 and Brazuca." Proceedings of the Institution of Mechanical Engineers, Part P: Journal of Sports Engineering and Technology 232, no. 4 (May 19, 2018): 342–48. http://dx.doi.org/10.1177/1754337118773214.

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Aerodynamic coefficients were determined for Telstar 18 and Brazuca, match balls for the 2018 and 2014 World Cups, respectively. Experimental determination of aerodynamic coefficients prompted the development of computationally determined soccer ball trajectories for most launch speeds experienced in actual play. Although Telstar 18’s horizontal range will be nearly 10% shorter than Brazuca’s horizontal range for high-speed kicks, both Telstar 18 and Brazuca have similar knuckling effects due to nearly equal critical speeds and high-speed drag coefficients that differ by less than 10%. Surface comparisons suggest why aerodynamic properties for the two World Cup balls are so similar.

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Young, Douglas E., Doris Trachtman, Irving S. Scher, and Richard A. Schmidt. "High School and College Baseball Pitchers' Response and Glove Movements to Line Drives." Journal of Applied Biomechanics 22, no. 1 (February 2006): 25–32. http://dx.doi.org/10.1123/jab.22.1.25.

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The timing of glove movements used by baseball pitchers to catch fast approaching balls (i.e., line drives) was examined in two tests to determine the responses and temporal characteristics of glove movements in high school and college baseball pitchers. Balls were projected toward the head of participants at 34.8 m·s–1 (78 mph) on average in an indoor test and at speeds approaching 58.1 m·s–1 (130 mph) in a field test. Pitchers caught over 80% and 15% of the projected balls in the indoor and field tests, respectively. Analyses of glove responses indicated that all pitchers could track the line drives and produce coordinated glove movements, which were initiated 160 ms (± 47.8), on average, after the ball was launched. College pitchers made initial glove movements sooner than high school pitchers in the field test (p = 0.012). In contrast, average glove velocity for pitchers increased from 1.33 (± 0.61) to 3.45 (± 0.86) m·s–1 across the tests, but did not differ between experience levels. Glove movement initiation and speed were unrelated, and pitchers utilized visual information throughout the ball's flight to catch balls that approached at speeds exceeding the estimated speeds in competitive situations.

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Fidgen, Jeffrey G., Mark C. Whitmore, and Jean J. Turgeon. "Ball sampling, a novel method to detect Adelges tsugae (Hemiptera: Adelgidae) in hemlock (Pinaceae)." Canadian Entomologist 148, no. 1 (June 1, 2015): 118–21. http://dx.doi.org/10.4039/tce.2015.29.

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AbstractDetection of the exotic hemlock woolly adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae), in the crown of eastern hemlock, Tsuga canadensis (Linnaeus) Carrière (Pinaceae), relies mainly on two techniques: (1) sampling of branches from the lower half of the crown using pole pruners; and, (2) visual examinations of accessible foliage from the ground. As a result, infestations starting elsewhere than the lower crown may be missed because the upper crown is out of reach for both techniques. We developed a novel technique called ball sampling, and evaluated its sensitivity at detecting a range of A. tsugae ovisac densities as estimated by pole pruning branch tips of T. canadensis. We launched racquet balls covered with VELCRO® patches of hooks through branches and examined them for the presence of wool produced by A. tsugae. Ball sampling was as effective as pole pruning at detecting infestations in individual trees. If A. tsugae abundance on branches was ⩾0.1 per 10 cm of twig length, as estimated by branch-tip sampling, ball sampling always detected wool in 10 or fewer samples. This technique has the potential to improve detectability of A. tsugae infestations because it can effectively access foliage that is typically inaccessible to other ground-based detection tools.

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Mahoney, John F., and Daniel P. Connaughton. "Launch Velocities in Successful Golf Putting: An Analytical Analysis." International Journal of Kinesiology and Sports Science 5, no. 2 (April 30, 2017): 24. http://dx.doi.org/10.7575/aiac.ijkss.v.5n.2p.24.

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Background: This study is concerned with the special case of a putted ball intersecting a standard golf hole at its diameter. The velocity of the ball at the initial rim of the hole is termed the launch velocity and depending upon its value the ball may either be captured or it may escape capture by jumping over the hole. The critical value of the launch velocity (V) is such that lesser values result in capture while greater values produce escape. Purpose: Since the value of the V entered prominently in some theoretical studies of putting, the aim of the current study is to provide an original re-evaluation of V and to contrast our results with existing results. Method: This analytical analysis relies on trigonometry in conjunction with Newtonian mechanics and the mathematics of projectiles. The results of a recent study into the mathematics of a bouncing ball which included the notions of restitution and friction were also employed in the analysis. Results: If bouncing and slipping do not occur when the ball hits the far rim of the hole our analysis produces a value of V of 1.356 m/s. When bouncing and slipping are present we find that V is at least 1.609 m/s but increases beyond this value as slipping and friction become greater. Useful relations which relate the dynamics and geometry of the ball to V are provided. Conclusion: Since ambient conditions may influence the extent of bounce and slippage we conjecture that the value of V is not unique.

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Alcock, Alison, Wendy Gilleard, Nick A. T. Brown, John Baker, and Adam Hunter. "Initial Ball Flight Characteristics of Curve and Instep Kicks in Elite Women’s Football." Journal of Applied Biomechanics 28, no. 1 (February 2012): 70–77. http://dx.doi.org/10.1123/jab.28.1.70.

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Initial ball flight characteristics of curve and instep kicks were investigated. Fifteen international female footballers performed curve and instep kicks from a distance of 20 m from goal and at a 1 m2 target. Seventeen Vicon cameras tracked three-dimensional coordinates of four reflective markers adhered to the ball. Ball flight characteristics were quantified, and the coordinates of the ball relative to the target center were recorded. The lateral launch angle and the angle of the spin axis relative to the horizontal best predicted the horizontal placement of the ball relative to the target. The vertical launch angle, antero-posterior velocity and amount of backspin best predicted the vertical coordinate. Regression models demonstrated how carefully controlled the flight characteristics must be with launch angles constrained within 3° to hit the target. Curve kicks were characterized by significantly greater lateral and vertical launch angles, increased sidespin and spin about the antero-posterior axis, and a more vertical spin axis. This information is beneficial for coaches in training players to achieve the characteristics required to score a goal and avoid a defensive wall. For example, if players consistently kick above or below the target, these findings identify the variables that will help rectify that error.

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Higuchi, Takatoshi, Jun Morohoshi, Tomoyuki Nagami, Hiroki Nakata, and Kazuyuki Kanosue. "The Effect of Fastball Backspin Rate on Baseball Hitting Accuracy." Journal of Applied Biomechanics 29, no. 3 (June 2013): 279–84. http://dx.doi.org/10.1123/jab.29.3.279.

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The effectiveness of fastballs of equivalent speed can differ; for example, one element of this difference could be due to the effect of rate and orientation of ball spin on launched ball trajectory. In the present experiment, baseball batters’ accuracy in hitting fastballs with different backspin rates at a constant ball velocity of 36 m/s was examined. Thirteen skilled baseball players (professionals, semiprofessionals, and college varsity players) participated in the study. The movements of bat and ball were recorded using two synchronized high-speed video cameras. The Pearson product-moment correlation coefficient (r) was calculated and used to analyze the relationship between ball backspin rate and the vertical distance between ball center and sweet spot at the moment of ball-bat impact. Ball backspin rate was positively correlated with increases in the distance from the optimal contact point of the swung bat (sweet spot) to the actual point of contact (r= .38,P< .001). Batters were most effective at the usual backspin rate for the ball velocity used. The decrease in accuracy of the batter’s swing that was observed when the fastball’s backspin deviated from the usual rate likely occurred because experienced batters predict ball trajectory from perceived ball speed.

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Cortela, Caio Corrêa, Juan Pedro Fuentes García, Michael Davis Higuera, and Layla Maria Campos Aburachid. "The transition process towards the yellow ball in tennis teaching." ITF Coaching & Sport Science Review 27, no. 79 (December 31, 2019): 31–33. http://dx.doi.org/10.52383/itfcoaching.v27i79.82.

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More than 10 years have gone by since Play and Stay campaign was launched, and even today, there is a lack of scientific studies focusing their strategies on the transition process between the stages that make up Tennis 10s. So, on the basis of interviews with expert coordinators, who are responsible for sport initiation programmes in Brazilian clubs, this study tries to describe the strategies used for the transition between the “green ball” and the “yellow ball”.

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Penner, A. R. "The physics of putting." Canadian Journal of Physics 80, no. 2 (February 1, 2002): 83–96. http://dx.doi.org/10.1139/p01-137.

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The motion of a rolling golf ball on a sloped golf green is modeled. The resulting calculated path of a golf ball is then used, along with a model of the capture of the golf ball by the hole, to determine the resulting launch conditions required for a successful putt. Estimates of the probability of making certain putts are also presented. PACS No.: 01.80+b

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Henrikson, Erik, Paul Wood, Chris Broadie, and Tom Nuttall. "The Role of Friction and Tangential Compliance on the Resultant Launch Angle of a Golf Ball." Proceedings 49, no. 1 (June 15, 2020): 27. http://dx.doi.org/10.3390/proceedings2020049027.

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A thorough understanding of how the delivered face angle and club path of a golf club influences the initial launch direction of a golf ball can play a significant role in the design of various club types as well as help players and coaches better understand performance in the field. A theoretical model based on a Hertzian impact formulation with the inclusion of tangential compliance via Coulomb friction is compared to empirical results. This comparison demonstrates that the initial launch direction of a golf ball for a given club path and face angle can be sufficiently predicted by the theoretical model, providing insights into the mechanisms leading to different launch direction percentages relative to face angle for various club types. Additionally, the relationship between launch direction and the coefficient of friction is explored for various angles of incidence.

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Richardson, Ashley K., Andrew CS Mitchell, and Gerwyn Hughes. "The effect of movement variability on putting proficiency during the golf putting stroke." International Journal of Sports Science & Coaching 13, no. 4 (April 4, 2018): 590–97. http://dx.doi.org/10.1177/1747954118768234.

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Movement variability has been considered important to execute an effective golf swing yet is comparatively unexplored regarding the golf putt. Movement variability could potentially be important considering the small margins of error between a successful and a missed putt. The aim of this study was to assess whether variability of body segment rotations influence putting performance (ball kinematic measures). Eight golfers (handicap range 0–10) performed a 3.2 m level putt wearing retro-reflective markers which were tracked using a three-dimensional motion analysis system sampling at 120 Hz. Ball roll kinematics were recorded using Quintic Ball Roll launch monitor. Movement (segment) variability was calculated based on a scalene ellipsoid volume concept and correlated with the coefficient of variation of ball kinematics. Statistical analysis showed no significant relationships between segment variability and putting proficiency. One significant relationship was identified between left forearm variability and horizontal launch angle, but this did not result in deficits in putting success. Results show that performance variability in the backswing and downswing is not related to putting proficiency or the majority of ball roll measures. Differing strategies may exist where certain golfers may have more fluid movement patterns thereby effectively utilising variability of movement. Therefore, golf instructors should consider movement variability when coaching the golf putt.

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Blenkinsop, Glen M., Ying Liang, Nicholas J. Gallimore, and Michael J. Hiley. "The Effect of Uphill and Downhill Slopes on Weight Transfer, Alignment, and Shot Outcome in Golf." Journal of Applied Biomechanics 34, no. 5 (October 1, 2018): 361–68. http://dx.doi.org/10.1123/jab.2017-0310.

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The aim of the study was to examine changes in weight transfer, alignment, and shot outcome during golf shots from flat, uphill, and downhill slopes. Twelve elite male golfers hit 30 shots with a 6-iron from a computer-assisted rehabilitation environment used to create 5° slopes while collecting 3-dimensional kinematics and kinetics of the swing. A launch monitor measured performance outcomes. A shift in the center of pressure was found throughout the swing when performed on a slope, with the mean position moving approximately 9% closer to the lower foot. The golfers attempted to remain perpendicular to the slope, resulting in weight transfer toward the lower foot. The golfers adopted a wider stance in the sloped conditions and moved the ball toward the higher foot at address. Ball speed was not significantly affected by the slope, but launch angle and ball spin were. As the coaching literature predicted, golfers were more likely to hit shots to the left from an uphill slope and to the right from a downhill slope. No consistent compensatory adjustments in alignment at address or azimuth were found, with the change in final shot dispersion resulting from the lateral spin of the ball.

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Muroga, Takeo, Hiroyuki Noto, Yoshimitsu Hishinuma, and Bo Huang. "Technical Advancement in Fabricating Dispersion Strengthened Copper Alloys by Mechanical Alloying and Hot Isostatic Pressing for Application to Divertors of Fusion Reactors." Materials Science Forum 941 (December 2018): 778–83. http://dx.doi.org/10.4028/www.scientific.net/msf.941.778.

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National Institute for Fusion Science (NIFS) launched in 2014 a research program for developing Dispersion Strengthened (DS) Cu alloys for application to the heat sink materials of divertors of fusion reactors, using newly installed ball-milling, encapsulation, and Hot Isostatic Pressing (HIP) facilities. A unique feature of these facilities is that the entire process can be performed without exposing the materials to air, enabling precise impurity control. Cu-Al, Cu-Zr and Cu-Y alloys have been produced in this program. Various technological advancement has been made for the fabrication, such as suppression of powder adhesion to the wall of containers during the ball milling, and encapsulation technology including development of small volume tubular capsules.

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Ikenaga, Masahiro, Nobue Okuma, Hiroki Nishiyama, Shinichiro Chiba, Katsutoshi Nishino, Go Omori, and Hiroyuki Nunome. "Influence of Ball Impact Location on Racquet Kinematics, Forearm Muscle Activation and Shot Accuracy during the Forehand Groundstrokes in Tennis." Proceedings 49, no. 1 (June 15, 2020): 89. http://dx.doi.org/10.3390/proceedings2020049089.

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We aimed to clarify the effect of ball–racquet impact locations on the dynamic behavior of tennis racquet, the accuracy of shots and muscle activation of the forearm. Eight male intermediate tennis players performed ten forehand groundstrokes. A motion capture system was used to measure the motions of racquet, ball and human body at 2000 Hz, and electromyography (EMG) activities of wrist extensor and flexor muscles were measured simultaneously. The flight parameters of the ball were measured by ballistic measurement equipment. All shots were divided into tertiles based on ball impact location along the lateral axis of tennis racquet. We found that the off-center, upper-side impact induces a larger muscular activity in extensor carpi radialis. Passive radial deviation of the wrist occurring immediately after ball impact may account for this. Furthermore, the off-center, upper-side impact could be associated with a missed shot having a lower, outward ball launch angle.

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Outland, Lauren, and Yolanda Alvarado. "Preventing cesareans with peanut ball use." Journal of Nursing Education and Practice 10, no. 1 (October 22, 2019): 107. http://dx.doi.org/10.5430/jnep.v10n1p107.

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The Association of Women's Health Obstetrical and Neonatal Nurses (AWHONN) has launched a Peanut Ball campaign to help curb the high rate of cesarean births in the United States. Cesarean births are especially likely in women who receive epidural anesthesia due to immobility and pelvic laxity. The peanut ball (PB) is a birthing ball that when placed between the mother's legs can increase pelvic dimensions and facilitate fetal descent and birth. For PB to increase vaginal deliveries (VDs), nurses on obstetrical wards need to “buy in” to using this innovation. Having “innovator” nurses on the shift helped disseminate the PB intervention and increased the rate of VDs. Using a retrospective study design that uses data collected for non-research purposes saves time and cost. Our retrospective study examined the difference in VDs with patient controlled epidural anesthesia (PCEA) in the first five months of 2016 prior to PB use compared with the same months in 2017 post intervention. Using a paired t-test we found a significant difference of successful PCEA vaginal births in 2016 compared to 2017 (p = .008). This relatively inexpensive and easy survey can be done by most obstetrical services and help AWHONN in their campaign to decrease the rate of cesarean sections.

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Penner, A. R. "The run of a golf ball." Canadian Journal of Physics 80, no. 8 (August 1, 2002): 931–40. http://dx.doi.org/10.1139/p02-035.

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The run, which includes both the bounce and the roll, of a golf ball landing on turf is modeled. The effect of launch speed, impact angle, backspin, and green firmness on the run for a variety of golf shots is considered. It is found that the dominant factor that determines the length of the run, in the case of drives, is the impact angle. It is also found that for high-lofted iron shots, where the golf ball is given sufficient backspin, the ball may, for firm enough greens, initially bounce forward before running backwards. PACS No.: 01.80+b

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Reigstad, Ole, and Magne Røkkum. "Wrist arthroplasty using prosthesis as an alternative to arthrodesis: design, outcomes and future." Journal of Hand Surgery (European Volume) 43, no. 7 (July 9, 2018): 689–99. http://dx.doi.org/10.1177/1753193418784707.

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We developed an uncemented screw-shaped ball-and-socket wrist prosthesis and modified it during a decade of trails from 1996 to 2005. The final Motec® wrist prosthesis was launched in 2006. Since then we have used this prosthesis in 110 wrists (110 patients) from 2006 to 2018. This article reviews the design, functional outcomes, complications, clinical usefulness and possible future modifications of the Motec® wrist prosthesis.

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Danaei, Behzad, William McNally, Erik Henrikson, and John McPhee. "Adjusting a Momentum-Based Golf Clubhead-Ball Impact Model to Improve Accuracy." Proceedings 49, no. 1 (June 15, 2020): 47. http://dx.doi.org/10.3390/proceedings2020049047.

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In this paper, two simple and physically meaningful adjustments were made to a momentum-based clubhead-ball impact model to predict golf ball launch conditions with better accuracy. These adjustments were motivated by two shortcomings of the momentum-based impact model, namely the absence of shaft effects and golf ball deformation. Kinematic data from a golf impact motion capture experiment was used to empirically determine the parameter adjustments that minimized the ball speed and spin errors. It was found that the original model’s ball speed deficiency could be corrected by adding less than 3 g to the clubhead mass, and the amount of added mass correlated with the mass of the shaft. Additionally, the original model’s backspin and sidespin errors were significantly reduced by making a slight adjustment to the golf ball’s center of mass position relative to the impact location. Specifically, moving the golf ball center of mass approximately 0.5 mm downward and 0.07 mm towards the heel reduced the mean backspin and sidespin errors by approximately 85% each.

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ITO, Shinichiro, Masaki HIRATSUKA, and Masafumi KITAJIMASU. "Estimation of Aerodynamic Characteristics of Tennis Balls by Using a Pneumatic Launcher Machine." Proceedings of the Symposium on sports and human dynamics 2020 (2020): B—4–3. http://dx.doi.org/10.1299/jsmeshd.2020.b-4-3.

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Choi, Young Hoon, Sung-Cheol Lee, and Sung Eun Kim. "Effect of Golf Club Path to Ball Launch Direction at Impact." Korean Journal of Sport Studies 57, no. 5 (September 30, 2018): 407–15. http://dx.doi.org/10.23949/kjpe.2018.09.57.5.29.

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SAKAI, Shinobu, and Yuya KITADE. "Development of launch mechanism in ball shooting machine with four rollers." Transactions of the JSME (in Japanese) 83, no. 856 (2017): 17–00225. http://dx.doi.org/10.1299/transjsme.17-00225.

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최상민. "A study on the narrative construction of TV drama, A dwarf launches a small ball." Journal of Korean drama and theatre ll, no. 26 (October 2007): 351–81. http://dx.doi.org/10.17938/tjkdat.2007..26.351.

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Benacka, Jan, and Igor Stubna. "Ball launched against an inclined plane – an example of using recurrent sequences in school physics." International Journal of Mathematical Education in Science and Technology 40, no. 5 (July 15, 2009): 696–705. http://dx.doi.org/10.1080/00207390902825344.

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WANG, Xi, Hanyu CHEN, and Xiaofeng LI. "Numerical simulation and characteristics investigation of golf ball trajectory." HKIE Transactions 26, no. 3 (September 27, 2019): 105–14. http://dx.doi.org/10.33430/v26n3thie-2018-0040.

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In this study, MATrixLABoratory (MATLAB)’s ode 45 method was adopted to investigate the effects of the three main factors on golf trajectory characteristics, and the preferred striking conditions were concluded. Meanwhile, the results of interaction analysis were used to assess the dependence of carry distance and peak height on each factor. Eventually, the realistic normal swing tests were conducted in a laboratory to confirm the validation and accuracy of the mathematical model. The simulated results showed that a faster club head speed generally enabled to improve carry distance. However, once the rotational speed was more than 3,000 r·min-1, the increased tendency of carry distance turned to decrease. Moreover, the decreased tendency was aggravated as the increase of club head speed and launch angle, but the low launch angle benefited to alleviate the decrease. Compared to the carry distance, peak height always rose in any conditions. Meanwhile, the combined effects of the three factors on carry distance were more obvious than on the peak height. Finally, the optimised striking strategies were concluded for golfer-slow, golfer-medium and golfer-fast, respectively.

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Lambeth, Jacob, Dustin Brekke, and Jeff Brunski. "Exploration of Center of Gravity, Moment of Inertia, and Launch Direction for Putters with Ball Speed Normalizing Face Properties." Proceedings 49, no. 1 (June 15, 2020): 2. http://dx.doi.org/10.3390/proceedings2020049002.

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The forgiveness of golf putters is traditionally achieved through weight distribution. Putters are often designed with large footprints, which help to increase the moment of inertia (MOI), but consequently move the center of gravity (CG) farther behind the face. The use of higher MOI putters will result in less ball speed loss on impacts away from the sweet spot (i.e., more forgiveness). It has been shown that certain face properties, such as milling patterns, grooves, or soft inserts, can be leveraged to have a similar effect. This paper explores the relationships between impact location, MOI, CG depth, discretionary mass placement, and launch direction for these putters. A novel design strategy is proposed. Minimizing CG depth for putters with ball speed normalizing face properties, even at the expense of MOI, can result in more consistent launch direction and distance control for the average player.

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Lopez, Shaun T. "On Race, Sports, and Identity: Picking Up the Ball in Middle East Studies." International Journal of Middle East Studies 41, no. 3 (August 2009): 359–61. http://dx.doi.org/10.1017/s0020743809091065.

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In their love for sports, Egyptians are no different from people in other parts of the world. They follow closely their favorite local teams in national-cup competitions, the careers of those stars who have taken their games to professional clubs in Europe, and, of course, the fortunes of their national teams in international competition. Success, such as Egypt's victory in the 2008 Africa Cup of Nations can draw millions into the streets of Cairo and Alexandria in celebration. Losses can result in full-scale political investigations launched by President Hosni Mubarak.

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Choi, Young Hyu, Sung Hyun Jang, and Ji Han Oh. "Influencing Factors on Stick-Slip Behavior of a Ball Screw Driven Elevation Mechanism for MLRS." Applied Mechanics and Materials 271-272 (December 2012): 958–68. http://dx.doi.org/10.4028/www.scientific.net/amm.271-272.958.

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As an MLRS (Multiple Launch Rocket System) cage is moved with a uniform speed through an elevation mechanism for MRLS operated using ball screws, its stick-slip behavior can be observed by the friction in a ball screw actuator. In this study, a single-degree of freedom mathematical model of an MLRS elevation system is designed and its stick-slip behavior is analyzed using a friction force model considering the Stribeck effect. The stability of a vibration system is analyzed through deriving an equation of normalized motion for the mathematical model and the influences of mechanical parameters and friction parameters on the vibration response and stability are theoretically analyzed.

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Betzler, Nils F., Stuart A. Monk, Eric S. Wallace, and Steve R. Otto. "The relationships between driver clubhead presentation characteristics, ball launch conditions and golf shot outcomes." Proceedings of the Institution of Mechanical Engineers, Part P: Journal of Sports Engineering and Technology 228, no. 4 (July 16, 2014): 242–49. http://dx.doi.org/10.1177/1754337114541884.

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Qing, Zhang, Wu Xuelei, Yang Xianxue, Li Hongbiao, and Feng Hao. "Failure analysis of steel ball in the brake operating cylinder of heavy launch vehicle." Engineering Failure Analysis 60 (February 2016): 353–62. http://dx.doi.org/10.1016/j.engfailanal.2015.11.056.

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Kanwar, Kiran D., and Mark D. Mann. "Effects of a golf swing intervention on senior golfers’ ball striking and motivation to play golf." International Journal of Sports Science & Coaching 13, no. 4 (April 16, 2018): 607–15. http://dx.doi.org/10.1177/1747954118764179.

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Several golf swing movements have been correlated with the production of club speed in skilled golfers. However, less skilled golfers, such as senior golfers, may not be capable of many of those movements. One golf swing—Minimalist Golf Swing—reduces the downswing range of motion through which a golfer’s body must move to reach the impact positions seen in skilled golfers. The purpose of this study was to assess whether the MGS could improve senior golfers’ ball flight and consistency, and increase their motivation to play golf. Twenty-two seniors (16 males, 6 females), aged 54–81, participated in an 11-session study comprising pretest, intervention, and posttest sessions. During the test sessions, participants hit 20 shots with each of their own 6-iron and driver clubs. Ball movement immediately after impact was measured using a camera-based ball launch monitor. Participants’ motivation to play golf before and after the intervention was assessed using the Sports Motivation Scale II. A mixed effects model was used for the statistical analysis of this repeated measures study, in which participants served as their own controls. Statistically significant per-session results were an increase in the ball’s speed (6-iron and driver) and trajectory (6-iron), and a change in direction (both clubs) from left to slightly right (for right handed golfers). Consistency of ball flight, total motivation and intrinsic motivation increased slightly post-intervention, while amotivation decreased, none significantly. Therefore, some senior golfers can improve ball flight, consistency, and motivation to play golf after six MGS training sessions.

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Herbig, Ulrike, Karl Markus Valent, Ulrich Pont, and Ardeshir Mahdavi. "Conserving the Paradise: Toward Sustainable Touristic Development in the Westmanggarai, Indonesia." Applied Mechanics and Materials 887 (January 2019): 282–91. http://dx.doi.org/10.4028/www.scientific.net/amm.887.282.

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Indonesia has a large variety of socio-spatial patterns that have developed over centuries. These settlement patterns correspond to the social, economic and landscape conditions and are part of the deeply rooted cultural heritage of Indonesia. The cultural heritage but also outstanding natural sites are base for an increasing popularity in tourism all over the Indonesian Archipelago. One of it is the island of Flores including the Komodo National Park that has been inscribed on the UNESCO World Heritage List. The town Labuan Bajo as the entry point to the national park is facing a rapid growth number of visitors after being declared as one of the focal points in of tourist development by the Indonesian government in 2016. With the Sepuluh Bali Baru (10 New Bali) concept the ministry of tourism launched a plan that aims to replicate the economic effects of tourism in Bali nationally. This development brought a number of challenges to the region especially concerning planning matters. One of the plans to deal with the different issues is to create an independent, international and interdisciplinary research center to support the local government, stakeholders and the population of Flores. This paper will describe first studies for a project launched in cooperation of the TU Wien (Vienna University of Technology), Universitas Gadjah Mada, National University of Singapore and the University of Sydney to develop a label for a sustainable tourism for the island if Flores starting with investigations in Labuan Bajo.

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Wool, Jon. "Facilitating Pretrial Justice in New Orleans." Federal Sentencing Reporter 24, no. 1 (October 1, 2011): 13–14. http://dx.doi.org/10.1525/fsr.2011.24.1.13.

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New Orleans in 2011 finds itself facing many of the same problems New York City faced in 1961 when the founders of the Vera Institute of Justice launched the Manhattan Bail Project: Too many people are held in pretrial detention who could be released without risk to public safety; the reliance on bail results in disparate outcomes based on financial ability; and the unnecessary detention of thousands of defendants each year imposes excessive costs on the city government and taxpayers, as well as on those needlessly detained. Vera is now working with New Orleans stakeholders to develop a comprehensive pretrial services system. Following in the footsteps of the Manhattan Bail Project, the work will create a carefully conceived and locally sensitive pretrial services system, one that will result in a fairer and more efficient criminal justice system and a safer community.

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Doaa Ghareeb. "The culture of suffering and Semiology of Irony: Perusal of a Korean novel “A dwarf launches a little ball”." Arabic Language&Literature 13, no. 2 (October 2009): 51–112. http://dx.doi.org/10.18630/kaall.2009.13.2.003.

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Driggers, Austin R., and Kimitake Sato. "The effects of vertically oriented resistance training on golf drive performance in collegiate golfers." International Journal of Sports Science & Coaching 13, no. 4 (November 24, 2017): 598–606. http://dx.doi.org/10.1177/1747954117743374.

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The purpose of this study was to examine the effects of vertically oriented resistance training on golf driving performance. Ten Division-I collegiate golfers completed two resistance training sessions per week for 10 weeks during the fall tournament season. Pre- and post-training assessments of strength-power and golf performance were compared. To assess strength-power, jump height, peak force, and peak power were measured from static and countermovement vertical jumps; peak force and rate of force development from 0 to 250 ms were measured from an isometric mid-thigh pull. Golf performance was assessed in terms of ball launch speed, spin rate, carry yardage, and total yardage, averaged from five shots using a driver. Following training, all measures of strength-power improved, with countermovement jump peak power improving significantly ( p < 0.00625). The golf performance assessment indicated significant increases ( p < 0.0125) in ball speed, carry yardage, and total yardage. These results suggest that vertically oriented resistance training can improve golf driving performance.

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Wallace, E. S., S. R. Otto, and A. Nevill. "Ball launch conditions for skilled golfers using drivers of different lengths in an indoor testing facility." Journal of Sports Sciences 25, no. 7 (May 2007): 731–37. http://dx.doi.org/10.1080/02640410601113221.

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Lim, Seo-Hee, and Jun-Hee Hong. "The Effect of Putter Face Rotation on the Launch Direction of Putted Ball in Putting Stroke." Journal of Golf Studies 14, no. 3 (September 30, 2020): 297–305. http://dx.doi.org/10.34283/ksgs.2020.14.3.25.

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Ningsih, Ni Putu Diah Untari, Soenarto Soenarto, and Sugiyono Sugiyono. "Pengembangan dan Pemberdayaan Masyarakat Desa Temukus-Besakih, Karangasem, Bali untuk Mendukung Pariwisata Berbasis Desa Wisata." TATALOKA 22, no. 2 (May 29, 2020): 212–21. http://dx.doi.org/10.14710/tataloka.22.2.212-221.

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Tourism has become a leading sector for Bali Province, especially Karangasem. Karangasem Regency continues to improve itself by continuing to develop tourism potential that has both the potential of nature, culture and customs. Bali Provincial Government in 2015-2018 through the Bali Mandara Volume II Program launched the establishment of 100 tourism villages, one of which was Temukus-Besakih Village. The purpose of this study is to develop and empower the people of Temukus-Besakih Village to support village-based tourism. The method used in this study is interpretative naturalistic, with the following steps: grand tours, observations, surveys, and literature studies with literature relating to the topic of research. The results showed the potential possessed by Temukus-Besakih Village in realizing tourism villages seen from the criteria of tourist villages, among others: attractions, distance traveled, religion, and infrastructure availability. The basic concept of developing Temukus-Besakih Village as a tourism village is "Sustainable Tourism Village". The concept of development of the basic concept consists of spatial plans, namely: environmental zones, socio-cultural zones, and economic zones.

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신근혜. "Comparative study on what “house” symbolizes in Thai novel No Way Out and Korean novel A Dwarf Launches a Little Ball." 동남아연구 24, no. 3 (January 2015): 83–103. http://dx.doi.org/10.21485/hufsea.2015.24.3.004.

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MacKenzie, Sasho, Luc Champoux, and Erik Henrikson. "Influence of Grip Mass on Driving Performance." Proceedings 49, no. 1 (June 15, 2020): 81. http://dx.doi.org/10.3390/proceedings2020049081.

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The purpose of the study was to determine the influence of grip mass on driver clubhead kinematics at impact as well as the resulting kinematics of the golf ball. Three club mass conditions (275, 325, and 375 g) were tested by 40 experienced golfers (handicap = 7.5 ± 5.3) representing a range of clubhead speeds (36 to 54 m/s). Each participant executed 12 drives per condition using matched grips and shafts and a single clubhead. Club mass was modified by inserting 50 g and 100 g into the grips of the two heavier conditions. The heaviest condition was associated with the slowest clubhead speed (p = 0.018) and highest vertical launch (p = 0.002), which resulted in no net influence on driving distance (p = 0.91). Lateral dispersion was greatest with the 325 g condition (p = 0.017), as was horizontal impact spot variability on the driver face (p = 0.031). Findings at the individual golfer level were not reliable enough to suggest that grip mass could be effectively used in a fitting environment to either shift ball flight tendencies or improve consistency.

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Fekih, Lassaad Ben, Georges Kouroussis, and Olivier Verlinden. "Spectral-Based Fatigue Assessment of Ball Grid Arrays under Aerospace Vibratory Environment." Key Engineering Materials 569-570 (July 2013): 425–32. http://dx.doi.org/10.4028/www.scientific.net/kem.569-570.425.

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Ball grid arrays (BGAs) embedded in aerospace devices should satisfy strict standards in the purpose to ensure their mechanical safety, particularly in fatigue. In fact, critical phases of BGAs service life such as launch lead to high cycle fatigue (HCF) failure due to severe random accelerations.To face this problem, designers are still using experimental qualifications based on deterministic time-domain fatigue methods. This work is motivated principally to study the applicability of the principal spectral fatigue models as cost effective alternative to assess BGA HCF. The study includes an assembly made up of a BGA chip and a support board. Finite element spectrum analysis brings out that the fatigue failure is expected to occur at different interconnect locations like for instance a critical solder joint made of a ductile tin-lead alloy. Among all the studied spectral models, it emerges that the Dirlik’s fatigue prediction is the most relevant in the typical range of the solder fatigue coefficients.

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Journal articles on the topic 'Ball launcher'

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