Production of muon pairs in the continuum region by 39.5 GeV/cπ±, K±, p and p beams incident on a copper target

General features of the inclusive hadroproduction of muon pairs of mass greater than 1.5 GeV/c² are shown. For incident π^?, the data extend up to M=5.7 GeV/c² (i.e.M²/s≈0.4). The scaling cross section M³dσ/dM for π^?N reactions is much flatter than that for pN reactions and exceeds the latter by two to three orders of magnitude at large M²/s.     

Probing the evaporation of ternary ethanol-methanol-water droplets by cavity enhanced Raman scattering

Cavity enhanced Raman scattering is used to characterise the evolving composition of ternary aerosol droplets containing methanol, ethanol and water during evaporation into a dry nitrogen atmosphere. Measurements made using non-linear stimulated Raman scattering from these ternary alcohol-water droplets allow the in situ determination of the concentration of the two alcohol components with high accuracy. The overlapping spontaneous Raman bands of the two alcohol components, arising from C-H stretching vibrational modes, are spectrally-resolved in stimulated Raman scattering measurements. We also demonstrate that the evaporation measurements are consistent with a quasi-steady state evaporation model, which can be used to interpret the evaporation dynamics occurring at a range of pressures at a particular evaporation time.     

Reactivity of di‐iodine toward thiol: Desulfuration reaction of 5‐nitro‐2‐mercapto‐benzimidazole upon reaction with di‐iodine

The reaction of 2‐mercapto‐benzoic acid (H₂MBA), 2‐mercato‐nicotinic acid (H₂MNA), and 2‐mercapto‐pyrimidine (PMTH) with a twofold molar amount of di‐iodine (I₂) results in the isolation of crystals of the neutral disulfides of formulae: {(HMBA)₂·1/2(CH₃CN)} ( 1 ), {(HMNA)₂·(H₂O)} ( 2 ), and (PMT)₂ ( 3 ), respectively, when dichloromethane/acetonitrile/methanol ( 1 ) or dichloromethane ( 2,3 ) were used as solvents. The reaction of di‐iodine with thethiol PMTH and 2‐mercapto‐benzothiazole (MBZTH) yields the disulfide (PMT)₂ ( 3 ), and the di‐iodine adduct of formula {[MBZTH‐I₂]·[MBZTH]₂} ( 4 ), respectively. The reaction of di‐iodine with 5‐nitro‐2‐mercapto‐benzimidazole (O₂N‐MBZIMH) ( 5 ) in the presence of ferric trichloride hydrate (FeCl₃·6H₂O), in a 6:3:1 (I₂:thiol:FeCl₃·6H₂O) molar ratio, results in cocrystal ( 6 ), which contain the desulfurated hydroxyl derivative O₂N‐BZIMOH ( 6a ) and unreacted O₂N‐MBZIMH ( 6b ) in a 3:1 molar ratio. The compounds were characterized by elemental analysis, FT‐IR, and ¹H NMR spectroscopy. The crystal structures of compounds 1 – 6 were also determined by X‐ray crystallography. Cyclic voltammetry measurements showed that thiols with low oxidation potentials (< 1.0 V) mainly form disulfides upon a reaction with di‐iodine, whereas those with higher oxidation potential form charge transfer (CT), resulting in desulfurated products, MBZIMH. However, in the case of O₂N‐MBZIMH a desulfurated species was isolated. The formation of the final product also requires the presence of FeCl₃. © 2012 Wiley Periodicals, Inc. Heteroatom Chem 23:498–511, 2012; View this article online at wileyonlinelibrary.com . DOI 10.1002/hc.21042     

On the dynamics of a nonlinear energy harvester with multiple resonant zones

Nonlinear Dynamics - The dynamics of a nonlinear vibration energy harvester for rotating systems is investigated analytically through harmonic balance, as well as by numerical analysis. The...     

Energy dependence of site‐specific radiation damage in protein crystals

It is important to consider radiation damage to crystals caused by data collection when solving structures and critical when determining protein function, which can often depend on very subtle structural characteristics. In this study the rate of damage to specific sites in protein crystals cooled at 100 K is found to depend on the energy of the incident X‐ray beam. Several lysozyme crystals were each subjected to 3–26 MGy of cumulative X‐ray exposure by collecting multiple data sets from each crystal at either 9 keV or 14 keV. The integrated electron density surrounding each S atom in the structure was calculated for each data set and the change in electron density was evaluated as a function of dose at the two energies. The rate of electron density decrease per cubic Å per MGy was determined to be greater at 14 keV than at 9 keV for cysteine sulfurs involved in disulphide bridges; no statistically significant differences in the decay rates were found for methionine sulfurs. These preliminary results imply that it might be possible to minimize certain types of specific radiation damage by an appropriate choice of energy. Further experiments studying a variety of photolabile sites over a wider range of energies are needed to confirm this conclusion.     

Split supersymmetry in brane models

Type-I string theory in the presence of internal magnetic fields provides a concrete realization of split supersymmetry. To lowest order, gauginos are massless while squarks and sleptons are superheavy. For weak magnetic fields, the correct Standard Model spectrum guarantees gauge coupling unification with sin² ϑW=3/8 at the compactification scale of M _GUT ⋍ 2 × 10¹⁶ GeV. I discuss mechanisms for generating gaugino and higgsino masses at the TeV scale, as well as generalizations to models with split extended supersymmetry in the gauge sector.     

Results from a set of low speed blade-vortex interaction experiments

The results of a Blade-Vortex Interaction (BVI) experiment are presented. The experiments were the second series to be carried out at Glasgow University (see Kokkalis and Galbraith 1986, 1987), and reflect improvement to the facility. These improvements have resulted in sufficient resolution to observe clear evidence of vortex passage and propagative disturbances caused by the BVI. Additionally the quality of the pressure data permitted a meaningful assessment of force and moment coefficients, and a clear correspondence between their detailed time histories was observed. The data obtained are also compared with the results of previous studies, and qualitative and quantitative similarities are discussed.     

C-bifurcations and period-adding in one-dimensional piecewise-smooth maps

This paper examines the behaviour of piecewise-smooth, continuous, one-dimensional maps that have been derived in the literature as normal forms for grazing and sliding bifurcations. These maps are linear for negative values of the parameter and non-linear for positive values of the parameter. Both C¹ and C² maps of this form are considered. These maps display both period-adding and period-doubling behaviour. For maps with a squared or 3/2 term the stability and existence conditions of fixed points and period-2 orbits in the vicinity of the border-collision are found analytically. These agree with the Feigin classification proposed by di Bernardo et al. [Chaos Solitons and Fractals 10 (1999) 1881]. The period-adding behaviour is examined in these maps, where analytical solutions for the boundaries of periodic solutions are found. Implicit equations for the boundaries of periodic windows for varying power term are also found and plotted. Thus, it is proved that period-adding scenarios are generic in maps of this form.