17 research outputs found
The rotation strategy in high-level European soccer teams
The purpose of the present study was to examine the rotation strategy in high-level soccer teams during a sequence of three games per week (1st domestic, 2nd European and 3rd domestic). Data were collected during the 2014-15, 2015-16, 2016-17 and 2017-18 competitive season for the soccer teams that were qualified in the quarter finals of the Champions League. Regression analysis showed that when a large number of players participated in the initial list for the three games, more points in the domestic league were lost. Similarly, increasing the changes of players in the initial list between the 1st and the 3rd game and between the 2nd and the 3rd game a negative effect on the domestic league was observed. In contrast, a positive effect of the number of changes of players in the starting line between the 1st and the 2nd game, regarding the total points won, was found. As the average time of the substitutes participated in the game increases in all three games, the total points of the teams are reduced. The biggest time of changes in the 2nd game had a negative impact on the points of European games. In order to achieve a more efficient rotation, coaches should have a qualitative and competitive roster of players. Furthermore, coaches should try to apply different tactics in previous matches in order, as many players as possible, to maintain high levels of homogeneity and competing readiness
Relationship between time and goal scoring of European soccer teams with different league ranking
The aim of the current study was to compare scored and conceded goals as well as the time period among teams of different league ranking. Researchers recorded the total games (n= 1446) of the top European leagues of Spain, Italy, Germany, and France for the period 2015-2016. The teams were divided into the ones which achieved their participation for European cups (L1), teams that remained to the category (L2), and teams which relegated to the lower category (L3). The researchers recorded the scored goals, the conceded goals, and the goal differences, per game, per half, and per 15min in total games for 2015-2016 season. The results showed that L1 teams were superior to L2 and L3 in overall goal scoring characteristics in both halves. The superior 15min periods were also explored. In addition, L2 teams performed higher than L3 teams in most of the variables. In conclusion, the difference between L1 with L2 and L3 teams is based in goal scoring during the whole game, in contrast with the difference between L2 and L3 teams that relies on stronger defense. On the other hand, L3 teams did not perform higher in any goal scoring pattern than the other two groups. It is obvious, that performance difference is achieved by the first half which is difficult to change during the second half. Thus, coaches have to emphasize achieving high performance in the first half of the game. Furthermore, they must use their substitutions so as to avoid poor performance periods and heighten the offensive and defensive play of their teams
Low temperature methane conversion with perovskite-supported exo/endo-particles
Lowering the temperature at which CH4 is converted to useful products has been long-sought in energy conversion applications. Selective conversion to syngas is additionally desirable. Generally, most of the current CH4 activation processes operate at temperatures between 600 and 900 °C when non-noble metal systems are used. These temperatures can be even higher for redox processes where a gas phaseâsolid reaction must occur. Here we employ the endogenous-exsolution concept to create a perovskite oxide with surface and embedded metal nanoparticles able to activate methane at temperatures as low as 450 °C in a cyclic redox process. We achieve this by using a non-noble, CoâNi-based system with tailored nano- and micro-structure. The materials designed and prepared in this study demonstrate long-term stability and resistance to deactivation mechanisms while still being selective when applied for chemical looping partial oxidation of methane
Endogenous nanoparticles strain perovskite host lattice providing oxygen capacity and driving oxygen exchange and CH4Â conversion to syngas
Particles dispersed on the surface of oxide supports have enabled a wealth of applications in electrocatalysis, photocatalysis, and heterogeneous catalysis. Dispersing nanoparticles within the bulk of oxides is, however, synthetically much more challenging and therefore less explored, but could open new dimensions to control material properties analogous to substitutional doping of ions in crystal lattices. Here we demonstrate such a concept allowing extensive, controlled growth of metallic nanoparticles, at nanoscale proximity, within a perovskite oxide lattice as well as on its surface. By employing operando techniques, we show that in the emergent nanostructure, the endogenous nanoparticles and the perovskite lattice become reciprocally strained and seamlessly connected, enabling enhanced oxygen exchange. Additionally, even deeply embedded nanoparticles can reversibly exchange oxygen with a methane stream, driving its redox conversion to syngas with remarkable selectivity and long term cyclability while surface particles are present. These results not only exemplify the means to create extensive, self-strained nanoarchitectures with enhanced oxygen transport and storage capabilities, but also demonstrate that deeply submerged, redox-active nanoparticles could be entirely accessible to reaction environments, driving redox transformations and thus offering intriguing new alternatives to design materials underpinning several energy conversion technologies
Dielectric Barrier Plasma Discharge Exsolution of Nanoparticles at Room Temperature and Atmospheric Pressure
Exsolution of metal nanoparticles (NPs) on perovskite oxides has been demonstrated as a reliable strategy for producing catalystâsupport systems. Conventional exsolution requires high temperatures for long periods of time, limiting the selection of support materials. Plasma direct exsolution is reported at room temperature and atmospheric pressure of Ni NPs from a model Aâsite deficient perovskite oxide (La0.43Ca0.37Ni0.06Ti0.94O2.955). Plasma exsolution is carried out within minutes (up to 15 min) using a dielectric barrier discharge configuration both with Heâonly gas as well as with He/H2 gas mixtures, yielding small NPs
Dielectric barrier plasma discharge exsolution of nanoparticles at room temperature and atmospheric pressure
Funding: his work was supported by EPSRC through the UK Catalysis Hub (EP/R027129/1) and the Emergent Nanomaterials-Critical Mass Initiative (EP/R023638/1, EP/R023921/1, EP/R023522/1, EP/R008841/1) as well as the Royal Society (IESâR2â212049). F.F. gratefully acknowledges support from the National Research Council of Italy (2020 STM program). I.S.M. acknowledges funding from the Royal Academy of Engineering through a Chair in Emerging Technologies Award entitled âEngineering Chemical Reactor Technologies for a Low-Carbon Energy Futureâ (Grant CiET1819â2â57). K.K. acknowledges funding from the Henry Royce Institute (EP/X527257/1), Royal Society (RGSâR2â222062), and EPSRC (EP/Y015487/1).Exsolution of metal nanoparticles (NPs) on perovskite oxides has been demonstrated as a reliable strategy for producing catalyst-support systems. Conventional exsolution requires high temperatures for long periods of time, limiting the selection of support materials. Plasma direct exsolution is reported at room temperature and atmospheric pressure of Ni NPs from a model A-site deficient perovskite oxide (La0.43Ca0.37Ni0.06Ti0.94O2.955). Plasma exsolution is carried out within minutes (up to 15 min) using a dielectric barrier discharge configuration both with He-only gas as well as with He/H2 gas mixtures, yielding small NPs (<30 nm diameter). To prove the practical utility of exsolved NPs, various experiments aimed at assessing their catalytic performance for methanation from synthesis gas, CO, and CH4 oxidation are carried out. Low-temperature and atmospheric pressure plasma exsolution are successfully demonstrated and suggest that this approach could contribute to the practical deployment of exsolution-based stable catalyst systems.Peer reviewe
Dielectric barrier plasma discharge exsolution of nanoparticles at room temperature and atmospheric pressure Dataset
The dataset that corresponds to the results reported in the paper are included within this record as an Excel file and with tabs corresponding to each figure. Additional results and raw data underlying this work (full set of microscopy images and size analysis and statistics, high resolution deconvoluted x-ray photoelectron spectra and control magnetic measurements) are available in the Supporting Information (in PDF format) or on request following instructions provided here. This work has been supported by EPSRC through the UK Catalysis Hub (EP/R027129/1) and the Emergent Nanomaterials-Critical Mass Initiative (EP/R023638/1, EP/R023921/1, EP/R023522/1, EP/R008841/1) as well as the Royal Society (IES\R2\212049). F.F. gratefully acknowledges support from the National Research Council of Italy (2020 STM program). I.S.M. acknowledges funding from the Royal Academy of Engineering through a Chair in Emerging Technologies Award entitled âEngineering Chemical Reactor Technologies for a Low-Carbon Energy Futureâ (Grant CiET1819\2\57). KK acknowledges funding from the Henry Royce Institute (EP/X527257/1)
The diagnosis and comparison of physical abilities of skiers and footballers
Purpose: The purpose of this research was to diagnose the physical abilities such as speed, strength, agility and endurance of alpine skiers and footballers through the same country tests. Also, the purpose was to compare the performance and test results of the above tested against one another. Methods: The sample of 58 individuals came from two groups of men of different sports: skiing (n = 29) aged 18-26 (20.97 ± 2.08 years) and football (n = 29) aged 18-25 (21, 28 ± 1.56 years), while the level in each group was the advanced and the beginner respectively. Until the trials, the ski and football teams had a training program exercising physical abilities and skills three days a week for the specialties and one day a week the select skiing session and the compulsory football session according to the curriculum. In order to diagnose and compare the physical abilities of ski students and football students, the following four tests of Alpine skiing on dry ground were used after the ski season on this day in April 2014: A) Route speed test (route 20m with flight start). B) Explosive power tests of the lower limbs (eightfold with alternating tossing of feet). C) Agility Tests (Slalom's track on a "folder" 5m x 5m). D) Anaerobic test (jumping obstacle 20cm height for 60sec). Results: In the skiing specialty we have a great correlation between speed tests and other physical abilities and agility with endurance (r = -0,72). In football specialty there was a great correlation between speed and power tests (r = - 0.65) and agility with the power (r = - 0.69). In optional skiing, we have a moderate correlation between the tests, while in the A year football students the correlation between speed and strength (r = - 0.81) is distinguished. Conclusions: It is noteworthy that the students of the first year of football as well as the specialists do not have as good results in endurance as compared to the students of the skiing, even though the football game lasts 90 minutes compared to Alpine skiing 1-2 minutes
Relative Age Effect: A Systematic Discrimination against Biologically Younger Athletes
Physical differences associated with birth-date among athletes of the same selection year have been described as the Relative Age Effect (RAE). The aim of this study was to examine whether RAE still exists in soccer and running sport disciplines as well as to evaluate its progress among different gender, age, and sport context and if it has an effect on performance. Using official archives of the international sportsâ associations (World Athletics-UEFA), birthdates and performance were collected for 7226 athletes (4033 males; 3198 females) who participated in soccer and running events. A chi-square test was used to assess differences between observed and expected birth date distributions. The study showed an over-representation of athletes born in the first quarter of the selection year for both soccer and running events. RAE is more obvious in younger age groups and in sports that require higher explosive speed, strength, power and anaerobic capacity such as soccer and short distance sprints. It was also found that RAE is associated with performance. In conclusion, athletes of younger age groups with greater biological age have a physical advantage in explosive sports (i.e. soccer and short distance running) that probably does not predict their future development