1,179 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
Get PDFThe 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
Get PDFThe 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
Interim report on public schools facilities study
No full textprepared by: Luis Caraballo, Task Force Chairman, Luis Javier Fernandez, Task Force Vice-Chairman, Subcommittee Chairmen Dennis Whitehouse, Assessment, Carol Samuels, Financial Issues, David Krumbien, Educational Standards ; with administrative support from: the Department of Administrative Services, Facilities Division.Title from PDF caption (viewed on February 25, 2020).This archived document is maintained by the State Library of Oregon as part of the Oregon Documents Depository Program. It is for informational purposes and may not be suitable for legal purposes.Mode of access: Internet from the Oregon Government Publications Collection.Text in English
Interacting bubble clouds and their sonochemical production
Get PDFInternational 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
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
Polymer multimode waveguide optical and electronic PCB manufacturing
No full textThe paper describes the research in the £1.3 million IeMRC Integrated Optical and Electronic Interconnect PCB Manufacturing (OPCB) Flagship Project in which 8 companies and 3 universities carry out collaborative research and which was formed and is technically led by the author. The consortium’s research is aimed at investigating a range of fabrication techniques, some established and some novel, for fabricating polymer multimode waveguides from several polymers, some formulations of which are being developed within the project. The challenge is to develop low cost waveguide manufacturing techniques compatible with commercial PCB manufacturing and to reduce their alignment cost. The project aims to take the first steps in making this hybrid optical waveguide and electrical copper track printed circuit board disruptive technology widely available by establishing and incorporating waveguide design rules into commercial PCB layout software and transferring the technology for fabricating such boards to a commercial PCB manufacturer. To focus the research the project is designing an optical waveguide backplane to tight realistic constraints, using commercial layout software with the new optical design rules, for a demonstrator into which 4 daughter cards are plugged, each carrying an aggregate of 80 Gb/s data so that each waveguide carries 10 Gb/s
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