flight distance
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2021 ◽  
Vol 11 (19) ◽  
pp. 9269
Author(s):  
Takehiro Tamaru ◽  
Masaki Hiratsuka ◽  
Shinichiro Ito

A floater serve in volleyball is a technique of serving a non-rotating or low-rotating ball, which is difficult to return because the flight path of the ball changes irregularly. On the other hand, the randomness of the trajectory makes it difficult for the ball to fall on the target. Players are required to serve taking into account the variability of the trajectory. In previous studies using wind tunnels, it was shown that aerodynamic characteristics such as drag force and lateral force applied to the ball vary depending on the type of ball and the orientation of the panel. Therefore, in order to control the flight trajectory, it is necessary to understand the aerodynamic characteristics of each ball. Since the velocity of the ball and the fluid force applied to the ball changes during flight, it is important to measure not only the fluid force at a steady state in the wind tunnel but also the actual flight distance of the ball. In this study, to provide valuable information for precise control of floater serves, we measured the drag force applied to the ball in a wind tunnel and the flight distance of the ball using an ejection machine, and clarified the effects of the type of ball and the panel face. In the drag force measurement, the drag force on three types of balls, V200W, MVA200, and FLISTATEC, was measured in the wind speed range of 4 m/s to 30 m/s. In the ejection measurement, the ball flight distances were measured while changing the orientation of the panel using an ejection machine. Basically, the FLISTATEC, MVA200, and V200W, in that order, were more likely to increase the distance and the variability, but it was shown that the drop point could be adjusted slightly by selecting the panel face. This result was also obtained when a human player actually served the ball, indicating the tactical importance of the player consciously controlling the direction of the panel. The tactical importance of the player’s conscious control of the direction of the panel was demonstrated. We also proposed receiver positions that would be effective based on the characteristics of each ball.


2021 ◽  
Vol 136 (9) ◽  
Author(s):  
Mogens Dam

AbstractAt FCC-ee, about $$1.7 \times 10^{11}\,\hbox {Z} \rightarrow \uptau ^+\uptau ^-$$ 1.7 × 10 11 Z → τ + τ - events will be produced. This high statistics in the clean $$\hbox {e}^+\hbox {e}^-$$ e + e - environment opens the possibility of much improved determinations of $$\uptau $$ τ -lepton properties and, via the measurement of the $$\uptau $$ τ polarisation, of the neutral-current couplings of electrons and $$\tau $$ τ s. Improved measurements of $$\uptau $$ τ -lepton properties—lifetime, leptonic branching fractions, and mass—allow important tests of lepton universality. The experimental challenge is to match as far as possible statistical uncertainties generally at the $$10^{-5}$$ 10 - 5 level. This applies in particular to the lifetime measurement, which is derived from the 2.2-mm $$\uptau $$ τ average flight distance, and for the branching fraction and polarisation measurements, where the cross-channel contamination is of particular concern. These issues raise strict detector requirements, in particular, on the accuracy of the construction and alignment of the vertex detector and of the precise calorimetric separation and measurement of photons and $$\uppi ^0$$ π 0 s in the collimated $$\uptau $$ τ decay topologies.


2021 ◽  
Vol 15 (8) ◽  
pp. 2324-2328
Author(s):  
Işik Bayraktar ◽  
Murat Çilli ◽  
Tuncay Örs

It is the flight distance which is approximately ninety percent of jump distance in long jump. On the other hand, there are many biomechanical factors that determine the flight distance and horizontal velocity is considered to be the most effective factor. The aim of this study was to create a jump distance estimation model based on run-up velocity that can practically be used by trainers. The research data was included 858 valid trials of 156 female Turkish long jumpers (ages: 17.8±3.4 years). According to the correlation results of the current study; a nonlinear regression model was used between the variables found to have the highest correlation (age, last 10 meter run-up velocity, jump distance). According to this model, 79.10% of the jump distance can be estimated with the variables of age and run-up velocity in the last ten meters. Developed to be used for female long jumpers at a broad performance level, this model may make it possible to make technical evaluations about whether the velocity, technique and strength of a female long jumper are stable. Keywords: long jump, velocity, age, prediction model


The Auk ◽  
2021 ◽  
Author(s):  
Sean M Williams ◽  
Catherine A Lindell

Abstract We investigated whether context-specific behavior is responsible for the cohesion of mixed-species flocks of antshrikes and antwrens in Amazonian Peru. Antshrikes perform a behavior while spatially repositioning, to which antwrens respond by approaching. The cohesion of interspecific associations requires communication, although the mechanisms often are unexplored. In monospecific groups, cohesion among individuals is maintained with actions or vocalizations given in a certain context. Dusky-throated Antshrikes (Thamnomanes ardesiacus) vocalize while in flight and the number of times they vocalize covaries with the flight distance. We refer to this pairing of flight and vocalization as repositioning behavior. Furthermore, antshrikes pair a different call type with perching, which we refer to as perching behavior. We followed Long-winged (Myrmotherula longipennis) and White-flanked Antwrens (M. axillaris) and recorded their response following natural vocalizations (no playback used) given by the antshrikes. Long-winged Antwrens, but not White-flanked, flew toward an antshrike significantly sooner and were more likely to approach the antshrikes after the repositioning behavior than after perching behavior. In addition, Long-winged Antwrens, but not White-flanked, flew toward an antshrike sooner after a longer series of repositioning calls than after a shorter series. We did not distinguish between the Long-winged Antwrens’ response as a function of movement vs. vocalizations of the antshrikes, although we argue that vocalizations are likely a more important communication component of repositioning behavior than movement. It remains unclear whether the antshrikes are deliberately signaling the Long-winged Antwrens or the antwrens are taking advantage of the repositioning behavior; active signaling is possible since antshrikes benefit from antwrens. White-flanked Antwrens may be less responsive to the antshrikes since they have a lower propensity to occur in a mixed-species flock. The results indicate that the repositioning behavior of Dusky-throated Antshrikes is a key mechanism of interspecific cohesion of Amazonian mixed-species flocks of the understory.


Author(s):  
Federico Lessio ◽  
Carolina Giulia Pisa ◽  
Luca Picciau ◽  
Mariangela Ciampitti ◽  
Beniamino Cavagna ◽  
...  

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Tamer Savas ◽  
Oznur Usanmaz ◽  
Ozlem Sahin ◽  
Ertan Çınar ◽  
Murat Karaderili

Purpose The study aims to design a new route model for unmanned aerial vehicles (UAVs) to integrate them into non-segregated airspace. Design/methodology/approach The proposed route model was assessed and validated through real-time simulations. Findings The comparison results of baseline and proposed route model show that a reduction of 38% and 41% in the total flight time and total flight distance were obtained in favour of the proposed model, respectively. Practical implications The proposed route model can be applied by airspace designers and UAV users to perform safe and efficient landing in non-segregated airspace. Originality/value In this study, a new proposed route model is constructed for UAVs. Quantitative results, using a real-time simulation method, are achieved in terms of flight distance and flight time.


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