Tennis Shoe Outsole Temperature Changes During Hard Court Sliding and Their Effects on Friction Behaviour

Tennis is a sport played around the world on a variety of surfaces like grass, clay and hard courts. The types of surface and the surface properties influence the movements that are used by players. On hard courts, players have recently increased their tendency to perform sliding movements, possibly to reposition faster and be ready for the next shot. In order to enhance player's performance and reduce injury risk, there is a need to understand the tribological mechanisms occurring at the shoe-surface contact. The present study has developed an effective method to accurately measure temperature changes throughout a sliding movement. Friction and temperature measurements of a commercial tennis shoe outsole were measured during simulated sliding over hard court surfaces. Results indicated how the temperature changed during and after a slide. Additionally, it was found that the temperature of the shoe sole is significantly affected by the vertical load applied, and this varies depending on the shoe location tested. It was also found an inconsistent effect of surface roughness under a range of vertical loads tested. For multiple sliding tests during a rally, the shoe will increase temperature incrementally for each new slide, which could result in large changes in friction behaviour during a slide. The findings from this study could have important implications for the sport of tennis, both in terms of performance and injury-risk

Experimental and numerical study of fast gas heating and O atom production in a capillary nanosecond discharge

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140420/1/6.2014-1030.pd

The local structure of SO2 and SO3 on Ni(1 1 1): a scanned-energy mode photoelectron diffraction study

O 1s and S 2p scanned-energy mode photoelectron diffraction (PhD) data, combined with multiple-scattering simulations, have been used to determine the local adsorption geometry of the SO2 and SO3 species on a Ni(1 1 1) surface. For SO2, the application of reasonable constraints on the molecular conformation used in the simulations leads to the conclusion that the molecule is centred over hollow sites on the surface, with the molecular plane essentially parallel to the surface, and with both S and O atoms offset from atop sites by almost the same distance of 0.65 Å. For SO3, the results are consistent with earlier work which concluded that surface bonding is through the O atoms, with the S atom higher above the surface and the molecular symmetry axis almost perpendicular to the surface. Based on the O 1s PhD data alone, three local adsorption geometries are comparably acceptable, but only one of these is consistent with the results of an earlier normal-incidence X-ray standing wave (NIXSW) study. This optimised structural model differs somewhat from that originally proposed in the NIXSW investigation

Reactions of Tetracyclone Molybdenum Complexes with Electrophilic Alkynes: Cyclopentadienone-Alkyne Coupling and Alkyne Coordination

The reactions of the complexes [Mo(CO)2(η4-C4Ph4CO)2] and [Mo(CO)3(NCMe)(η4-C4Ph4CO)] with the alkynes dimethyl acetylenedicarboxylate (DMAD; RC≡CR where R = CO2Me) and methyl propiolate (RC≡CH) have been studied. In the case of DMAD, the initial product is the green carbonyl complex [Mo(CO)(RC≡CR)(η5,σ-C4Ph4COCR═CR)] (3), in which two alkyne molecules have been incorporated: one is linked to the carbonyl group of the tetracyclone ligand, whereas the other is π-bound to the metal as a four-electron donor. Oxidation of this compound affords yellow [Mo(O)(RC≡CR)(η5,σ-C4Ph4COCR═CR)] (8). When the π-acceptor carbonyl ligand is replaced by the π-donor oxo group, the alkyne ligand changes orientation: it lies parallel to the Mo–CO bond in 3 but perpendicular to the Mo═O group in 8. Analogous complexes (9, 10) were isolated in the case of methyl propiolate; each exists as a mixture of two isomers depending on the orientation of the unsymmetrical alkyne ligand

Reactions of Tetracyclone Molybdenum Complexes with Electrophilic Alkynes: Cyclopentadienone-Alkyne Coupling and Alkyne Coordination

The reactions of the complexes [Mo(CO)2(η4-C4Ph4CO)2] and [Mo(CO)3(NCMe)(η4-C4Ph4CO)] with the alkynes dimethyl acetylenedicarboxylate (DMAD; RC≡CR where R = CO2Me) and methyl propiolate (RC≡CH) have been studied. In the case of DMAD, the initial product is the green carbonyl complex [Mo(CO)(RC≡CR)(η5,σ-C4Ph4COCR═CR)] (3), in which two alkyne molecules have been incorporated: one is linked to the carbonyl group of the tetracyclone ligand, whereas the other is π-bound to the metal as a four-electron donor. Oxidation of this compound affords yellow [Mo(O)(RC≡CR)(η5,σ-C4Ph4COCR═CR)] (8). When the π-acceptor carbonyl ligand is replaced by the π-donor oxo group, the alkyne ligand changes orientation: it lies parallel to the Mo–CO bond in 3 but perpendicular to the Mo═O group in 8. Analogous complexes (9, 10) were isolated in the case of methyl propiolate; each exists as a mixture of two isomers depending on the orientation of the unsymmetrical alkyne ligand

Electron Electric Dipole Moment from Lepton Flavor Violation

The general Minimal Supersymmetric Standard Model introduces new sources for Lepton Flavor Violation (LFV) as well as CP-violation. In this paper, we show that when both sources are present, the electric dipole moment of the electron, $d_e$, receives a contribution from the phase of the trilinear $A$-term of staus, $\phi_{A_\tau}$. For $\phi_{A_\tau}=\pi/2$, the value of $d_e$, depending on the ratios of the LFV mass elements, can range between zero and three orders of magnitude above the present bound. We show that the present bound on $d_e$ rules out a large portion of the CP-violating and the LFV parameter space which is consistent with the bounds on the LFV rare decays. We show that studying the correlation between $d_e$ and the P-odd asymmetry in $\tau \to e\gamma$ helps us to derive a more conclusive bound on $\phi_{A_\tau}$ We also discuss the possibility of cancelation among the contributions of different CP-violating phases to $d_e$.Comment: 35 pages, 9 figure

Classical heisenberg antiferromagnet away from the pyrochlore lattice limit: entropic versus energetic selection

The stability of the disordered ground state of the classical Heisenberg pyrochlore antiferromagnet is studied within extensive Monte Carlo simulations by introducing an additional exchange interaction $J'$ that interpolates between the pyrochlore lattice ($J'=0$) and the face-centered cubic lattice ($J'=J$). It is found that for $J'/J$ as low as $J'/J\ge 0.01$, the system is long range ordered : the disordered ground state of the pyrochlore antiferromagnet is unstable when introducing very small deviations from the pure $J'=0$ limit. Furthermore, it is found that the selected phase is a collinear state energetically greater than the incommensurate phase suggested by a mean field analysis. To our knowledge this is the first example where entropic selection prevails over the energetic one.Comment: 5 (two-column revtex4) pages, 1 table, 7 ps/eps figures. Submitted to Phys. Rev.

Higher serum immunoglobulin G3 levels may predict the development of multiple sclerosis in individuals with Clinically Isolated Syndrome

Clinically isolated syndrome (CIS) is a first episode of neurological symptoms that may precede a diagnosis of multiple sclerosis (MS). Therefore, studying individuals with CIS may lead to breakthroughs in understanding the development and pathogenesis of MS. In this study, serum levels of immunoglobulin (Ig)G, IgA, IgM, and IgG1–4 were measured in 20 people with CIS and compared with those in 10 healthy controls (HC) and 8 people with MS. Serum Ig levels in individuals with CIS were compared with (a) the time to their conversion from CIS to MS, (b) serum levels of antibodies to Epstein–Barr virus, (c) frequencies of T regulatory (Treg), T follicular regulatory (Tfr), and B cell subsets, and (d) Treg/Tfr expression of Helios. Serum IgG, IgM, and IgG2 levels were significantly lower in people with CIS than HC, and IgG, IgM, and IgG1 levels were significantly lower in people with CIS than MS. After adjusting for age, sex, and serum 25(OH) vitamin D3 [25(OH)D] levels, CIS was associated with lower serum levels of IgG and IgG2 compared with HC (p = 0.001 and p < 0.001, respectively). People with MS had lower IgG2 levels (p < 0.001) and IgG2 proportions (%IgG; p = 0.007) compared with HC. After adjusting for age, sex, and 25(OH)D, these outcomes remained, in addition to lower serum IgA levels (p = 0.01) and increased IgG3 levels (p = 0.053) in people with MS compared with HC. Furthermore, serum from people with MS had increased proportions of IgG1 and IgG3 (p = 0.03 and p = 0.02, respectively), decreased proportions of IgG2 (p = 0.007), and greater ratios of “upstream” to “downstream” IgG subclasses (p = 0.001) compared with HC. Serum IgG3 proportions (%IgG) from people with CIS correlated with the frequency of plasmablasts in peripheral blood (p = 0.02). Expression of Helios by Treg and Tfr cell subsets from individuals with CIS correlated with levels of serum IgG2 and IgG4. IgG3 levels and proportions of IgG3 (%IgG) in serum at CIS diagnosis were inversely correlated with the time until conversion to MS (p = 0.018 and p < 0.001, respectively), suggesting they may be useful prognostic markers of individuals with CIS who rapidly convert to MS

Hadronic Electromagnetic Properties at Finite Lattice Spacing

Electromagnetic properties of the octet mesons as well as the octet and decuplet baryons are augmented in quenched and partially quenched chiral perturbation theory to include O(a) corrections due to lattice discretization. We present the results for the SU(3) flavor group in the isospin limit as well as the results for SU(2) flavor with non-degenerate quarks. These corrections will be useful for extrapolation of lattice calculations using Wilson valence and sea quarks, as well as calculations using Wilson sea quarks and Ginsparg-Wilson valence quarks.Comment: 19 pages, 0 figures, RevTeX