606 research outputs found
Dataset for Cavity collapse near slot geometries
No full textThis dataset supports the publication: Cavity collapse near slot geometries
E.D. Andrews, D. Fernandez Rivas and I.R. Peters, Journal of Fluid Mechanics (2020)</span
Dataset in support of the journal article 'Bubble collapse near porous plates'
No full textThis dataset supports the publication: 'Bubble collapse near porous plates' by Elijah D. Andrews, David Fernández Rivas, and Ivo R. Peters, Journal of Fluid Mechanics (2023)</span
sj-docx-1-sph-10.1177_19417381221083319 – Supplemental material for The Association Between Chronological Age and Maturity Status on Lower Body Clinical Measurements and Asymmetries in Elite Youth Tennis Players
No full textSupplemental material, sj-docx-1-sph-10.1177_19417381221083319 for The Association Between Chronological Age and Maturity Status on Lower Body Clinical Measurements and Asymmetries in Elite Youth Tennis Players by Alejandro Lopez-Valenciano, Francisco Ayala, Mark B.A. De Ste Croix, David Barbado, Víctor Moreno-Perez, David Sanz-Rivas and Jaime Fernandez-Fernandez in Sports Health: A Multidisciplinary Approach</p
Cavity collapse near slot geometries
Full text linkThe collapse of a gas or vapour bubble near a solid boundary produces a jet directed towards the boundary. High surface pressure and shear stress induced by this jet can damage, or clean, the surface. More complex geometries will result in changes in collapse behaviour, in particular the direction of the jet. The majority of prior research has focused on simple flat boundaries or cases with limited complexity. There is currently very little known about how complex geometries affect bubble collapse. We numerically and experimentally investigate how a slot in a flat boundary affects the jet direction for a single bubble. We use a boundary element model to predict how the jet direction depends on key geometric parameters and show that the results collapse to a single curve when the parameters are normalised appropriately. We then experimentally validate the predictions using laser-induced cavitation and compare the experimental results to the predicted dependencies. This research reveals a tendency for the jet to be directed away from a slot and shows that the jet direction is independent of slot height for slots of sufficient height
Bubble collapse near porous plates
Full text linkThe collapse of a gas or vapour bubble near a non-porous boundary is directed
at the boundary due to the asymmetry induced by the nearby boundary. High
surface pressure and shear stress from this collapse can damage, or clean, the
surface. A porous boundary, such as a filter, would act similarly to a
non-porous boundary but with reduced asymmetry and thus reduced effect. Prior
research has measured the cleaning effect of bubbles on filters using
ultrasonic cleaning, but it is not known how the bubble dynamics are
fundamentally affected by the porosity of the surface. We address this question
experimentally by investigating how the standoff distance, porosity, pore size,
and pore shape affect two collapse properties: bubble displacement and bubble
rebound size. We show that these properties depend primarily on the standoff
distance and porosity of the boundary and extend a previously developed
numerical model that approximates this behaviour. Using the numerical model in
combination with experimental data, we show that bubble displacement and bubble
rebound size each collapse onto respective single curves
Grain boundary networks and shape preferred orientation – : A fresh angle on pattern quantification with GBPaQ
Full text linkFunding Information: The author acknowledges support from an Aberdeen-Curtin Alliance International Postgraduate Scholarship and a Curtin Publication Grant. The author thanks Chris Elders for supervision throughout this project, the PhD thesis examiners Thomas Blenkinsop, Steve Reddy, Mark Jessell, and Ian Alsop for their contributions to this work, the two referees, who gave valuable input for this publication, and Isabel Zutterkirch for helpful discussions. David Healy acknowledges funding from the UKRI NERC grant NE/T007826/1 . Enrique Gomez-Rivas acknowledges the “Ramón y Cajal” fellowship RYC2018-026335-I , funded by the Spanish Ministry of Science and Innovation (MCIN) / State Research Agency of Spain (AEI) / European Regional Development Fund (ERDF) / 10.13039/501100011033 , the DGICYT research project PID2020-585 118999GB-I00 , funded by the Spanish Ministry of Science and Innovation (MCIN) / State Research Agency of Spain (AEI) / 10.13039/501100011033 , and the Grup Consolidat de Recerca “Geologia Sedimentària” ( 2021 SGR-Cat 00349 ), funded by the Catalan Council .. Publisher Copyright: © 2023 The AuthorsPeer reviewe
Interacting bubble clouds and their sonochemical production
Full text linkInternational audienceAcoustically driven air pockets trapped in artificial crevices on a sur- face can emit bubbles which organize in (interacting) bubble clusters. With increasing driving power Fernandez Rivas et al. [Angew. Chem. Int. Ed., 2010] observed three different behaviors: clusters close to the very pits out of which they had been created, clusters pointing toward each other, and merging clusters. The latter behavior is highly undesired for technological purposes as it is associated with a reduction of the radical production and an enhancement of the erosion of the reactor walls. The dependence on the control parameters such as the distance of the pits and the conditions for cluster-merging are examined. The underlying mechanism, governed by the secondary Bjerknes forces, turns out to be strongly influenced by the nonlinearity of the bubble oscillations and not directly by the number of nucleated bubbles. The Bjerknes forces are found to dampen the bubble oscillations, thus reducing the radical production. Therefore, the increased number of bubbles at high power could be the key to understand the experimental observation that, after a certain power threshold, any further increase of the driving does not improve the sonochemical efficiency
Introduction to property theory - the fundamental theorems
Full text linkThe market system consists of a price mechanism, built on the foundation of a system of property, and contract. In many developing, and transition economies, the market system functions poorly. In many cases, if not most, the malfunctioning is not simply in the price system (for example, anti-competitive activities), but in the underlying property system (such as contracts being breached, and externalities in the sense of transfers not covered by contracts). Economic theory tends to take the functioning of the system of property, and contract for granted, and focuses on the operation of the price mechanism. Property theory focuses on the underlying system of property, and contract. In this paper, the author inaugurates the mathematical treatment of property theory.In contrast with earlier work in"law and economics", and the"new institutional economics", this approach uses principles drawn from jurisprudence, and does not attempt to reduce"law"to"economics"in the sense of efficiency considerations, such as the minimization of transaction costs. The main results are the two fundamental theorems of property theory that are analogous to the two fundamental theorems of price theory that, in essence, state that: 1) A competitive equilibrium is Pareto optimal. 2) Given a Pareto optimal state, there exists a set of prices such, that a competitive equilibrium at those prices would realize that Pareto optimal state.Environmental Economics&Policies,Labor Policies,Banks&Banking Reform,Municipal Housing and Land,Economic Theory&Research,Environmental Economics&Policies,Banks&Banking Reform,Economic Theory&Research,Municipal Housing and Land,Land and Real Estate Development
The effects of a compensatory training program adding an isoinertial device in the shoulder function on young tennis players
No full textFernandez-Fernandez, J, Moreno-Perez, V, Cools, A, Nakamura, FY, Teixeira, AS, Ellenbecker, T, Johansson, F, and Sanz-Rivas, D. The effects of a compensatory training program adding an isoinertial device in the shoulder function on young tennis players. J Strength Cond Res 37(5): 1096-1103, 2023-The aim of this study was to analyze whether a compensatory training program, including isoinertial flywheel training, could reduce shoulder imbalances in a group of asymptomatic young tennis players. After an initial evaluation, 26 young tennis players were assigned to either a supervised flywheel training group (FTG, n = 13) or a control group (CG, n = 13). Shoulder passive internal (IR) and external rotation (ER) range of motion (ROM) as well as shoulder IR and ER maximal isometric strength were measured before and after a 12-week training intervention, performed 3 times per week. After the intervention, results showed significant changes for IR (p < 0.001, effect size [ES] = 1.83) and ER (p < 0.001, ES = 1.77) on the dominant (D) side, and IR on the nondominant (ND) side (p < 0.001, ES = 2.24) in the FTG compared with the CG. Regarding the ROM values, results showed that the FTG achieved significantly greater increases for the IR ROM (p < 0.001, ES = 3.32) and total ROM (TROM) (p = 0.004, ES = 1.39) on the D and ND sides (IR ROM: p = 0.002, ES = 1.53; TROM: p < 0.001, ES = 2.35) than the CG. Moreover, the CG displayed larger decrements in ER ROM (p = 0.016, ES = 1.12) on the ND side after the training period than the FTG. The conducted compensatory training program was effective to increase the ER strength and IR mobility of the FTG players, which led to a reduction in the glenohumeral imbalances.Fernandez-Fernandez, J, Moreno-Perez, V, Cools, A, Nakamura, FY, Teixeira, AS, Ellenbecker, T, Johansson, F, and Sanz-Rivas, D. The effects of a compensatory training program adding an isoinertial device in the shoulder function on young tennis players. J Strength Cond Res 37(5): 1096-1103, 2023-The aim of this study was to analyze whether a compensatory training program, including isoinertial flywheel training, could reduce shoulder imbalances in a group of asymptomatic young tennis players. After an initial evaluation, 26 young tennis players were assigned to either a supervised flywheel training group (FTG, n = 13) or a control group (CG, n = 13). Shoulder passive internal (IR) and external rotation (ER) range of motion (ROM) as well as shoulder IR and ER maximal isometric strength were measured before and after a 12-week training intervention, performed 3 times per week. After the intervention, results showed significant changes for IR (p < 0.001, effect size [ES] = 1.83) and ER (p < 0.001, ES = 1.77) on the dominant (D) side, and IR on the nondominant (ND) side (p < 0.001, ES = 2.24) in the FTG compared with the CG. Regarding the ROM values, results showed that the FTG achieved significantly greater increases for the IR ROM (p < 0.001, ES = 3.32) and total ROM (TROM) (p = 0.004, ES = 1.39) on the D and ND sides (IR ROM: p = 0.002, ES = 1.53; TROM: p < 0.001, ES = 2.35) than the CG. Moreover, the CG displayed larger decrements in ER ROM (p = 0.016, ES = 1.12) on the ND side after the training period than the FTG. The conducted compensatory training program was effective to increase the ER strength and IR mobility of the FTG players, which led to a reduction in the glenohumeral imbalances.A
Sequencing Effects of Neuromuscular Training on Physical Fitness in Youth Elite Tennis Players
No full textFernandez-Fernandez, J, Granacher, U, Sanz-Rivas, D, Sarabia Marin, JM, Hernandez-Davo, JL, and Moya, M. Sequencing effects of neuromuscular training on physical fitness in youth elite tennis players. J Strength Cond Res 32(3): 849-856, 2018-The aim of this study was to analyze the effects of a 5-week neuromuscular training (NMT) implemented before or after a tennis session in prepubertal players on selected components of physical fitness. Sixteen high-level tennis players with a mean age of 12.9 +/- 0.4 years participated in this study, and were assigned to either a training group performing NMT before tennis-specific training (BT; n = 8) or a group that conducted NMT after tennis-specific training (AT; n = 8). Pretest and posttest included: speed (5, 10, and 20 m); modified 5-0-5 agility test; countermovement jump (CMJ); overhead medicine ball throw (MBT); and serve velocity (SV). Results showed that the BT group achieved positive effects from pretest to posttest measures in speed (d = 0.52, 0.32, and 1.08 for 5, 10, and 20 m respectively), 5-0-5 (d = 0.22), CMJ (d = 0.29), MBT (d = 0.51), and SV (d = 0.32), whereas trivial (10 m, 20 m, CMJ, SV, and MBT) or negative effects (d = -0.19 and -0.24 for 5 m and 5-0-5, respectively) were reported for the AT group. The inclusion of an NMT session before the regular tennis training led to positive effects from pretest to posttest measures in performance-related variables (i.e., jump, sprint, change of direction capacity, as well as upper-body power), whereas conducting the same exercise sessions after the regular tennis training was not accompanied by the same improvements
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