Smart Bat : a baseball swing analysis and training product

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2005.Includes bibliographical references (p. 21).Few products exist that offer any form of feedback on a hitter's baseball swing. Since bat speed is so critical in hitting for power, a low cost device that gives information on bat speed and/or acceleration is needed. By having a visual and auditory response indicating the magnitude of acceleration, a batter can get a better idea of how much their swing is improving. That hitter could also work on maintaining control of a bat at different speeds. The SmartBat product meets this customer need. Using an accelerometer embedded on the side of a regular wooden baseball bat, it measures acceleration and outputs the signal to an LED bar display driver. This consists of 10 LEDs in a row. The number of LEDs that light up after a swing is directly proportional to bat acceleration. In addition, whistles at the end of the bat provide auditory feedback by whistling louder at higher speeds. The current prototype would be able to be sold for $40, less than half of existing swing speed radars. There is also significant room for future improvements based on customer feedback, including a digital display of speed and acceleration, as well as the ability to record data onto a computer for further analysis.by Ethan Trangle.S.B

Hysteresis of Backflow Imprinted in Collimated Jets

We report two different types of backflow from jets by performing 2D special relativistic hydrodynamical simulations. One is anti-parallel and quasi-straight to the main jet (quasi-straight backflow), and the other is bent path of the backflow (bent backflow). We find that the former appears when the head advance speed is comparable to or higher than the local sound speed at the hotspot while the latter appears when the head advance speed is slower than the sound speed bat the hotspot. Bent backflow collides with the unshocked jet and laterally squeezes the jet. At the same time, a pair of new oblique shocks are formed at the tip of the jet and new bent fast backflows are generated via these oblique shocks. The hysteresis of backflow collisions is thus imprinted in the jet as a node and anti-node structure. This process also promotes broadening of the jet cross sectional area and it also causes a decrease in the head advance velocity. This hydrodynamic process may be tested by observations of compact young jets.Comment: 9 pages, 5 figures, accepted for publication in ApJ

Hysteresis of Backflow Imprinted in Collimated Jets

We report two different types of backflow from jets by performing 2D special relativistic hydrodynamical simulations. One is anti-parallel and quasi-straight to the main jet (quasi-straight backflow), and the other is bent path of the backflow (bent backflow). We find that the former appears when the head advance speed is comparable to or higher than the local sound speed at the hotspot while the latter appears when the head advance speed is slower than the sound speed bat the hotspot. Bent backflow collides with the unshocked jet and laterally squeezes the jet. At the same time, a pair of new oblique shocks are formed at the tip of the jet and new bent fast backflows are generated via these oblique shocks. The hysteresis of backflow collisions is thus imprinted in the jet as a node and anti-node structure. This process also promotes broadening of the jet cross sectional area and it also causes a decrease in the head advance velocity. This hydrodynamic process may be tested by observations of compact young jets.Comment: 9 pages, 5 figures, accepted for publication in ApJ

PENGARUH METODE LATIHAN LOOSE HANDS DRILL DAN STEP BACK DRILL TERHADAP SPEED BAT HASIL PUKULAN UNTUK CABANG OLAHRAGA SOFTBALL

Penelitian ini menguraikan pengamatan tentang metode latihan loosehands drill dan step back drill terhadap speed bat pada atlet atau pemain softball. Masalah dalam penelitian ini adalah masih rendahnya atlet atau pemain softball saat memukul bola dengan menghadapi pitcher yang cepat. Cara pemecahannya dilakukan dengan memberikan treatment dengan dua cara yaitu dengan metode latihan loose hands drill dan step back drill. Loosehands drill merupakan latihan yang membuat pemain atau atlet merasa rileks saat memegang bat. Sedangkan step back drill merupakan latihan dengan ada gerakan kaki depan ke belakang lalu melangkah ke depan. Pemberian treatment dilakukan sebanyak 16 kali pertemuan kepada atlet atau pemain UKM softball putri. Tujuan dari penelitian ini adalah untuk meningkatkan speed bat saat memukul bola softball yang diberikan oleh pitcher yang cepat. Setelah diberikan treatment atlet atau pemain terdapat peningkatan dari metode latihan loose hands drill dari data tes awal dengan rata-rata 76.31 dan tes akhir 79.47, sedangkan untuk metode latihan step back drill tes awal dengan rata-rata 23.80 dan tes akhir 27.62. Sehingga dari kedua treatment yang diberikan terdapat peningkatan. ;---This study describes the observations about loose hands drill and step bac k drill methods on speed bat on athletes or softball players. Problems in this study is still low athletes or softball players when hitting the ball by facing a fast pitcher. How to solve it done by providing treatment in two ways that is by training methods loose hands drill and step back drill. Loose hands drill is an exercise that makes the player or athlete feel relaxed while holding the bat. While the step back drill is an exercise with no front foot movement to the back and then stepped forward. Provision of treatment conducted as much as 16 meetings to athletes or female players softball. The purpose of this research is to increase speed bat when hitting softball ball given by fast pitcher. After athlete or player treatment there is an increase of loose hands drill training methods from preliminary test data with an average of 76.31 and a final test of 79.47, while for the preliminary step back drill practice model with an average of 23.80 and a final test of 27.62. So from the second treatment given there is an increase

Scattering of a Baseball by a Bat

A ball can be hit faster if it is projected without spin but it can be hit farther if it is projected with backspin. Measurements are presented in this paper of the tradeoff between speed and spin for a baseball impacting a baseball bat. The results are inconsistent with a collision model in which the ball rolls off the bat and instead imply tangential compliance in the ball, the bat, or both. If the results are extrapolated to the higher speeds that are typical of the game of baseball, they suggest that a curveball can be hit with greater backspin than a fastball, but by an amount that is less than would be the case in the absence of tangential compliance.Comment: Accepted for publication in American Journal of Physic

Mitigating the negative impacts of tall wind turbines on bats: Vertical activity profiles and relationships to wind speed.

Wind turbines represent a source of hazard for bats, especially through collision with rotor blades. With increasing technical development, tall turbines (rotor-swept zone 50-150 m above ground level) are becoming widespread, yet we lack quantitative information about species active at these heights, which impedes proposing targeted mitigation recommendations for bat-friendly turbine operation. We investigated vertical activity profiles of a bat assemblage, and their relationships to wind speed, within a major valley of the European Alps where tall wind turbines are being deployed. To monitor bat activity we installed automatic recorders at sequentially increasing heights from ground level up to 65 m, with the goal to determine species-specific vertical activity profiles and to link them to wind speed. Bat call sequences were analysed with an automatic algorithm, paying particular attention to mouse-eared bats (Myotis myotis and Myotis blythii) and the European free-tailed bat (Tadarida teniotis), three locally rare species. The most often recorded bats were the Common pipistrelle (Pipistrellus pipistrellus) and Savi's pipistrelle (Hypsugo savii). Mouse-eared bats were rarely recorded, and mostly just above ground, appearing out of risk of collision. T. teniotis had a more evenly distributed vertical activity profile, often being active at rotor level, but its activity at that height ceased above 5 ms-1 wind speed. Overall bat activity in the rotor-swept zone declined with increasing wind speed, dropping below 5% above 5.4 ms-1. Collision risk could be drastically reduced if nocturnal operation of tall wind turbines would be restricted to wind speeds above 5 ms-1. Such measure should be implemented year-round because T. teniotis remains active in winter. This operational restriction is likely to cause only small energy production losses at these tall wind turbines, although further analyses are needed to assess these losses precisely

Determining proper bat activity survey methods for the monitoring of the effect of Pseudogymnoascus destructans in Michigan bat populations.

MammalogyPseudogymnoascus destructans, a fungal infection of European origin, was introduced to Michigan in the spring of 2014. The fungus is believed to wake hibernating bats more often than normal, which can be a problem because coming out of torpor decreases fat stores and makes it hard for bats to survive the winter months. It is important to determine an effective way to survey bat activity and obtain a baseline measurement of bat activity before P. destructans affects Michigan bat populations. Our study aims to find a way to monitor bat activity in order to give us an idea of how P. destructans might affect bat colonies. We monitored bat activity along two routes at the University of Michigan Biological Station (45.56 N, 84.67 W) for 7 weeks and compared it with wind speed, time after sunset, temperature, lunar phase, barometric pressure, humidity, and date. Our measurement of bat activity was strongly positively associated with time after sunset (Least-Squares Regression Slope=-0.02, F=16.674, p<0.001) and temperature (Least-Squares Regression Slope=2.08, F=4.851, p=0.034). We also found a decreasing relationship, although not statistically significant, between bat activity and date (Least-Squares Regression Slope=-0.502, F=2.511, p=0.122). Our results showed that an effective way to monitor bat activity is by monitoring activity on warmer nights closer to sunset. This allows studies to control for the variables that impact bat activity and focus on the effect of P. destructans.http://deepblue.lib.umich.edu/bitstream/2027.42/110788/1/Burrell_Galen_2014.pd