Mean Jump Distance and Activation Length of Moving Dislocations in Al-Li Alloys

Author(s):  
J.Th.M. de Hosson ◽  
O. Kanert
Keyword(s):  
1971 ◽  
Vol 42 (9) ◽  
pp. 3388-3392 ◽  
Author(s):  
Masamitsu Kosaki ◽  
Koichi Sugiyama ◽  
Masayuki Ieda

1994 ◽  
Vol 116 (2) ◽  
pp. 164-171 ◽  
Author(s):  
P. D. Schreuders ◽  
K. R. Diller ◽  
J. J. Beaman ◽  
H. M. Paynter

A one-dimensional multicomponent kinetic model was developed to simulate the interstitial diffusion of macromolecules in a three component system, consisting of water, the macromolecule and the interstitial matrix. Movement of the individual components was modeled as occurring in finite jumps between discrete low energy wells along paths defined in terms of species occupation. The flow rate was expressed as a function of the local species concentration, the jump distance, and a kinetic frequency parameter. The model, implemented in pseudo-bond graph form, was examined by fitting it to data obtained for the transport of fluorescein tagged dextran to determine the kinetic constants for that specific system.


2021 ◽  
pp. 1-8
Author(s):  
John R. Harry ◽  
John Krzyszkowski ◽  
Luke D. Chowning ◽  
Kristof Kipp

This study sought to identify potential predictors of standing long jump (SLJ) performance using force–time strategy metrics within the unloading, eccentric yielding, eccentric braking, and concentric phases. Fifteen National Collegiate Athletic Association division 1 male soccer players (19 [1] y, 1.81 [0.94] m, 80.3 [22.4] kg) performed 3 maximum-effort SLJs, while 3-dimensional ground reaction force (GRF) data were obtained. Regularized regression models were used to investigate associations between force–time strategy metrics and 2 metrics of SLJ performance (ie, jump distance and modified reactive strength index). Jump height and eccentric yielding time were the only predictors of jump distance that also demonstrated large correlations to jump distance. Anterior–posterior unloading yank, average concentric vertical force, and concentric phase duration were the only predictors of modified reactive strength index that also demonstrated large correlations to modified reactive strength index. To maximize SLJ distance in high-level soccer athletes, human performance practitioners could design interventions to drive changes in strategy to increase jump height and decrease eccentric yielding time. To improve SLJ explosiveness, interventions to drive changes in unloading and concentric force application and decrease concentric time could be emphasized. Importantly, unique variable combinations can be targeted when training for SLJ distance and explosiveness adaptations.


1995 ◽  
Vol 11 (2) ◽  
pp. 142-162 ◽  
Author(s):  
William P. Berg ◽  
Nancy L. Greer

This study determined the kinematics of the final 11 steps of the long jump approach (LJA) for 19 novice long jumpers. Associations between takeoff accuracy and jump performance were identified, and comparisons of LJA kinematics were made with previous investigations of horizontal jumps performed by expert long jumpers. Results indicated that absolute takeoff error was not an important determinant of jump distance for the novice long jumpers. Additionally, novice jumpers differed from expert jumpers in terms of the relationships among specific variables. The results suggest that kinematic variables that appear to be causally related to jump performance in experts may not piay a similar role in the performance of novices. Hypotheses for these differences were offered. Differences between the LJAs of novice and expert long jumpers warrant further investigation, so that their origins can be determined and used to develop effective training regimes.


2019 ◽  
Vol 33 (19) ◽  
pp. 1950210 ◽  
Author(s):  
Mohamed Abd Allah El-Hadidy

In this paper, we present the multivariate distribution of independent Lévy flight jump diffusion molecules that cause water pollution. We consider that the waiting time of this jump has a Gaussian distribution. Rather than studying the statistical properties of this distribution in water, we estimate the length of the jump distance parameters for each molecule. These estimated jump distances of the molecules are used to predict the proportion of pollution in a large area of the sea.


2021 ◽  
Vol 13 (2) ◽  
pp. 128-135
Author(s):  
Argyro Kotsifaki ◽  
Vasileios Korakakis ◽  
Philip Graham-Smith ◽  
Vasileios Sideris ◽  
Rod Whiteley

Background: Single-leg vertical and horizontal hop tests are commonly used to assess performance of healthy athletes and as a measure of progress during rehabilitation from knee injury. It is unclear if they measure similar aspects of leg function, as the relative joint contributions of the hip, knee, and ankle joints during propulsion and landing are unknown. Hypothesis: The proportion of work done by the hip, knee, and ankle will not be the same for these 2 jump types and will vary for propulsive and landing phases. Study Design: Cross-sectional cohort study. Level of Evidence: Level 3. Methods: Twenty physically active participants completed instrumented single-leg hop analysis in both vertical and horizontal directions. Joint peak power, work generated or absorbed, and percentage contribution of each joint during propulsive and landing phases were compared between tasks using paired t tests. Results: Vertical hop was performed with roughly similar contributions of the hip, knee, and ankle for both propulsion (31%, 34%, 35%, respectively) and landing (29%, 34%, 37%, respectively). Horizontal hop distance was mostly (87%) determined by the hip and ankle (44% and 43%), but landing was mostly (65%) performed by the knee with lesser contribution from the hip and ankle (24% and 11%). Propulsive phase showed a proximal-to-distal temporal sequence for both hop types, but landing was more complex. Conclusion: Performance during vertical and horizontal hops (jump height and jump distance, respectively) measures different aspects of hip, knee, and ankle function during the propulsive and landing phases. Clinical Relevance: Assessment of knee joint function during rehabilitation should not be done using a horizontal hop. The knee contributes about a third to vertical hop height, but only about an eighth to horizontal hop distance. Practitioners carrying out performance testing using either vertical or horizontal hops should be mindful of the relative contributions for meaningful training inferences to be derived.


1998 ◽  
Vol 30 (Supplement) ◽  
pp. 116 ◽  
Author(s):  
J. Brand ◽  
J. A. Nyland ◽  
T. Armsey ◽  
R. Shapiro

2012 ◽  
Vol 36 (3) ◽  
pp. 297-305 ◽  
Author(s):  
L Nolan ◽  
Benjamin L Patritti ◽  
Kathy J Simpson

Background: Increasing numbers of long jumpers with lower limb amputations choose to take off from their prosthetic limb. It is not yet known what difference in technique, if any, this requires, or which is more advantageous. Objectives: To investigate kinematic differences in long jump technique in athletes with a unilateral transtibial ampution (TT) who take off from their prosthetic limb versus those who take off from their intact limb. Study Design: Naturalistic, field-based, observational; independent group, nonparametric comparison. Methods: Two-dimensional sagittal plane kinematic analysis was performed on all athletes competing in the men’s Paralympic TT long jump finals. Five athletes took off from their prosthetic limb (TOprosth) and five from their intact limb (TOintact). Results: No differences were seen between the two groups in terms of jump distance, approach speed or vertical velocity at touch down. While in contact with the take-off board, the two groups gained a similar amount of vertical velocity. However, the TOprosth group appeared to conserve horizontal velocity by using the prosthesis as a ‘springboard’, minimizing the large hip and knee range of motion displayed by the TOintact group and athletes in previous studies. Conclusions: While differences in technique were observed, no difference was found for jump distance. Clinical relevance Athletes choosing to take-off from their prosthetic limb in long jump require a different technique to those who choose to take-off from their intact limb. Knowledge of the correct technique can help reduce excessive training which can lead to injury, particularly in the residual limb.


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