scholarly journals Identification of the acceleration phase in the 100 meters dash race attending to kinematic variable

2018 ◽  
Vol 13 (37) ◽  
pp. 39-50
Author(s):  
Manuel Nogueras Miranda ◽  
Ignacio Grande Rodríguez ◽  
Carlos Alberto Cordente Martínez
Keyword(s):  
Kinematic Variable ◽  
Acceleration Phase

scholarly journals A Wind-Storage Combined Frequency Regulation Control Strategy Based on Improved Torque Limit Control

2021 ◽  
Vol 13 (7) ◽  
pp. 3765
Author(s):  
Benxi Hu ◽  
Fei Tang ◽  
Dichen Liu ◽  
Yu Li ◽  
Xiaoqing Wei
Keyword(s):  
Control Strategy ◽  
Storage System ◽  
Energy Storage System ◽  
Frequency Regulation ◽  
Small Scale ◽  
Acceleration Phase ◽  
Deceleration Phase ◽  
Combined Control ◽  
Inertial Response ◽  
Battery Energy

The doubly-fed induction generator (DFIG) uses the rotor’s kinetic energy to provide inertial response for the power system. On this basis, this paper proposes an improved torque limit control (ITLC) strategy for the purpose of exploiting the potential of DFIGs’ inertial response. It includes the deceleration phase and acceleration phase. To shorten the recovery time of the rotor speed and avoid the second frequency drop (SFD), a small-scale battery energy storage system (BESS) is utilized by the wind-storage combined control strategy. During the acceleration phase of DFIG, the BESS adaptively adjusts its output according to its state of charge (SOC) and the real-time output of the DFIG. The simulation results prove that the system frequency response can be significantly improved through ITLC and the wind-storage combined control under different wind speeds and different wind power penetration rates.

scholarly journals A conceptual model of cyclical glacier flow in overdeepenings

2014 ◽  
Vol 8 (4) ◽  
pp. 4463-4495 ◽  
Author(s):  
J. B. Turrin ◽  
R. R. Forster
Keyword(s):  
Conceptual Model ◽  
The Other ◽  
Acceleration Phase ◽  
Alaska Range ◽  
Deceleration Phase ◽  
Surface Slopes ◽  
Glacier Dynamics ◽  
Major Tributary ◽  
Cyclical Behavior ◽  
Glacier Flow

Abstract. A nearly four-decade, satellite-based velocity survey of the largest glaciers in the Alaska Range, Chugach Mountains, and the Wrangell Mountains of southern Alaska, spanning the early- to mid-1970s through the 2000s, reveals nine pulsing glaciers: Capps, Copper, Eldridge, Kahiltna, Matanuska, Nabesna, Nizina, Ruth, and Sanford glaciers. The pulses increase velocity by up to 2449% (Capps Glacier) or as little as 77% (Nabesna Glacier), with velocity increases for the other glaciers in the range of 100–250%. The pulses may last from between six years (Copper Glacier) to 12 years (Nizina Glacier) and consist of a multi-year acceleration phase followed by a multi-year deceleration phase during which significant portions of each glacier move en masse. The segments of each glacier affected by the pulses may be anywhere from 14 km (Sanford Glacier) to 36 km (Nabesna Glacier) in length and occur where the glaciers are either laterally constricted or joined by a major tributary, and the surface slopes at these locations are very shallow, 1–2°, suggesting the pulses occur where the glaciers are overdeepened. A conceptual model to explain the cyclical behavior of these pulsing glaciers is presented that incorporates the effects of glaciohydraulic supercooling, glacier dynamics, surface ablation, and subglacial sediment erosion, deposition, and deformation in overdeepenings.

scholarly journals The Effects of a Running Consistency Programme on Footfall Variability and Performance in the Long Jump

2016 ◽  
Vol 23 (3) ◽  
pp. 145-152
Author(s):  
Marcin Starzak ◽  
Hubert Makaruk ◽  
Anna Starzak
Keyword(s):  
Training Programme ◽  
Control Group ◽  
Education Students ◽  
Acceleration Phase ◽  
Physical Education Students ◽  
Step Velocity ◽  
Post Test ◽  
Long Jump ◽  
And Performance ◽  
Experimental Group

Abstract Introduction. The main purpose of this study was to evaluate the effect of a training programme aimed to enhance toe-toboard consistency on footfall variability and performance in the long jump. Material and methods. The study involved 36 male physical education students. The experimental group participated in a 12-week training programme, whereas the control group was limited to taking part in the classes held at university. All participants performed 6 long jump trials during two testing sessions. The kinematic parameters were assessed using the Optojump Next device and were further analysed to determine the variability of footfall placement during the approach run. Results. The analysis revealed a significant (p < 0.01) decrease in footfall variability in the experimental group between the pre-test and post-test. After the completion of the training programme, the participants significantly (p < 0.05) improved their take-off accuracy. Additionally, they significantly (p < 0.05) increased their velocity in the last five steps before take-off and the effective distance of the jump (p < 0.001). Conclusions. The results of this study indicate that through specific training, it is possible to improve the consistency of the steps in the acceleration phase of the approach run in the long jump. Moreover, decreasing footfall variability helps achieve a more stable step pattern which may be beneficial for greater accuracy at the take-off board and makes it possible to increase step velocity at the final stage of the approach run.

scholarly journals Hip Range of Motion and Strength and Energy Flow During Windmill Softball Pitching

2021 ◽  
Author(s):  
Gretchen D. Oliver ◽  
Kyle Wasserberger ◽  
Anne de Swart ◽  
Kenzie Friesen ◽  
Jessica Downs ◽  
...  
Keyword(s):  
Range Of Motion ◽  
Energy Flow ◽  
Injury Risk ◽  
External Rotation ◽  
Whole Body ◽  
Net Energy ◽  
Acceleration Phase ◽  
Hip Range Of Motion ◽  
Flow Through ◽  
The Relationship

Context Inadequate hip range of motion (ROM) and isometric strength (ISO) may interfere with energy flow through the kinetic chain and result in increased injury susceptibility. Objective To examine the relationship of hip ROM and ISO with energy flow through the trunk and pitching-arm segments during the windmill softball pitch in youth athletes. A subsequent purpose was to examine the relationship between energy flow and pitch speed. Design Descriptive laboratory study. Setting University research laboratory. Patients or Other Participants A sample of 29 youth softball pitchers (age = 11.2 ± 1.3 years, height = 155.0 ± 10.4 cm, mass = 53.2 ± 12.6 kg). Main Outcome Measure(s) Bilateral hip internal-rotation and external-rotation (ER) ROM and ISO were measured. Net energy outflow and peak rates of energy outflow from the distal ends of the trunk, humerus, and forearm were calculated for the acceleration phase of the windmill softball pitch, and pitch speed was measured. Results Regression analysis revealed an effect of drive-hip ER ISO on the net energy flow out of the distal ends of the trunk (P = .045) and humerus (P = .002). Specifically, increased drive-hip ER ISO was associated with increased net energy outflow from the trunk to the humerus and from the humerus to the forearm. No significant effects of hip ROM or other hip ISO measures were observed. Additionally, pitchers who achieved higher peak rates of distal outflow tended to achieve higher pitch speeds. Conclusions An association was present between drive-hip ER ISO and the net energy flow out of the distal ends of the trunk and humerus during the acceleration phase of the windmill softball pitch, emphasizing the importance of hip and lower body strength in executing the whole-body windmill pitch. Overall, energy-flow analysis is an interesting new way to analyze pitching mechanics and will aid in furthering our understanding of performance and injury risk in windmill softball pitching.

Effects of Hip Range of Motion and Isometric Strength on Energy Flow during Windmill Softball Pitching

2021 ◽  
Author(s):  
Gretchen D. Oliver ◽  
Kyle Wasserberger ◽  
Anne de Swart ◽  
Kenzie Friesen ◽  
Jessica Downs ◽  
...  
Keyword(s):  
Range Of Motion ◽  
Energy Flow ◽  
External Rotation ◽  
Isometric Strength ◽  
Whole Body ◽  
Net Energy ◽  
Acceleration Phase ◽  
Hip Range Of Motion ◽  
Flow Through ◽  
The Relationship

Abstract Context:Inadequate hip range of motion (ROM) and isometric strength (ISO) may interfere with energy flow through the kinetic chain and result in increased injury susceptibility. Objective:To examine the relationship of hip ROM and ISO with energy flow through the trunk and pitching arm segments during the windmill softball pitch in youth athletes. A subsequent purpose was to examine the relationship between energy flow and pitch speed. Design:Descriptive laboratory study. Setting:University research laboratory. Participants:A sample of 29 youth softball pitchers (11.2±1.3 yrs.; 155.0±10.4 cm; 53.2±12.6 kg). Main Outcome Measure(s):Bilateral hip internal rotation (IR) and external rotation (ER) ROM and ISO were measured. Net energy outflow and peak rates of energy outflow from the distal ends of the trunk, humerus, and forearm were calculated for the acceleration phase of the windmill softball pitch, and pitch speed was measured. Results:Regression analysis revealed a significant effect of drive hip ER ISO on the net energy flow out of the distal ends of the trunk (p=0.045) and humerus (p=0.002). Specifically, increased drive hip ER ISO was associated with increased net energy outflow from the trunk to the humerus and from the humerus to the forearm. No significant effects of hip ROM or other hip ISO measures were observed. Additionally, pitchers who achieved higher peak rates of distal outflow tended to also achieve higher pitch speeds. Conclusions:There is an association between drive hip ER ISO and the net energy flow out of the distal ends of the trunk and humerus during the acceleration phase of the windmill softball pitch, emphasizing the importance of hip and lower body strength in the execution of the whole-body windmill pitch. Overall, energy flow analysis is an interesting new way to analyze pitching mechanics and will aid in further understanding of performance and injury risk in windmill softball pitching.

scholarly journals Cosmological dynamics of f(R) models in dynamical system analysis

2020 ◽  
Vol 35 (22) ◽  
pp. 2050124
Author(s):  
Parth Shah ◽  
Gauranga C. Samanta
Keyword(s):  
Dynamical System ◽  
Asymptotic Behavior ◽  
Critical Points ◽  
System Analysis ◽  
Late Time ◽  
Field Equations ◽  
Acceleration Phase ◽  
First Case ◽  
Acceleration Of The Universe ◽  
The Universe

In this work we try to understand the late-time acceleration of the universe by assuming some modification in the geometry of the space and using dynamical system analysis. This technique allows to understand the behavior of the universe without analytically solving the field equations. We study the acceleration phase of the universe and stability properties of the critical points which could be compared with observational results. We consider an asymptotic behavior of two particular models [Formula: see text] and [Formula: see text] with [Formula: see text], [Formula: see text], [Formula: see text] for the study. As a first case we fix the value of [Formula: see text] and analyze for all [Formula: see text]. Later as second case, we fix the value of [Formula: see text] and calculation are done for all [Formula: see text]. At the end all the calculations for the generalized case have been shown and results have been discussed in detail.

Analysis of ABS Plastic and Concentric Cylindrical Shells’ Chemical Detonation Scatter Process

2014 ◽  
Vol 574 ◽  
pp. 421-424
Author(s):  
Yue Guo Shen ◽  
Nai Juan Du ◽  
Jun Hai Zhang
Keyword(s):  
Mathematical Model ◽  
Water Molecules ◽  
Initial Moment ◽  
Acceleration Phase ◽  
Phase Form ◽  
Scatter Process ◽  
Deceleration Phase ◽  
Liquid Ring ◽  
Scatter Experiment ◽  
Phase Motion

In this paper, basing on the FAE theory, simulating the process of scatter from chemical detonation about ABS plastic and concentric cylindrical shell according to experiment, on the basis of the assumption that the initial moment of the explosion being at the source ,we analyzed the gaseous phase motion equation and liquid ring controlling equation, and build the liquid ring movement mathematical model, then analyze the scatter process according to the chemical detonation scatter experiment, and classify the chemical detonation scatter into acceleration phase and deceleration phase, form the initial fog group, then we can reveal the mechanism of changing the chemical detonation into the fog. After the initial fog being formed, the effect of the chemical detonation disappeared, and the water molecules are uniformly dispersed into the air.

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