Search for X(3872) in gammagamma fusion and radiative production at CLEO

We report on a search for the recently reported X(3872) state using 15.1 fb(-1) of e(+)e(-) data taken in the sqrt[s] = 9.46-11.30 GeV region. Separate searches for the production of the X(3872) in untagged gammagamma fusion and e(+)e(-) annihilation following initial state radiation are made by taking advantage of the unique angular correlation between the leptons from the decay J/psi --> l(+)l(-) in X(3872) decay to pi(+)pi(-)J/psi. No signals are observed in either case, and 90% confidence upper limits are established as (2J+1)Gamma(gammagamma)(X(3872))B(X --> pi(+)pi(-)J/psi) < 12.9 eV and Gamma(ee)(X(3872))B(X- -> pi(+)pi(-)J/psi) < 8.3 eV.     

Modeling,Analysis, and Simulation of Biofilm Formation and Decay

In this article, we give a brief overview of our recent work on continuum mechanical modelling and simulation of microbial films. This comprises some classical tasks of applied mathematics such as computational fluid dynamics, analysis of partial differential equations, and mathematical biology.     

Determination of iron in the presence of large amounts of phosphate by titration with disodium dihydrogen ethylenediaminetetraacetate

Ferric iron, even in the presence of comparatively large amounts of phosphate, can be determined by titrating with the disodium salt of ethylenediaminetetraacetic acid (Versenate, Complexone III), using ammonium thiocyanate as indicator and extracting the red ferric thiocyanate into amyl alcohol, provided the pH is controlled at 2.0—2.4 at the end-point. The method has been successfully used for the determination of iron in phosphate-containing deposits from steam boilers.     

Hydrodynamic Limit of Brownian Particles Interacting with Short- and Long-Range Forces

We investigate the time evolution of a model system of interacting particles moving in a d-dimensional torus. The microscopic dynamics is first order in time with velocities set equal to the negative gradient of a potential energy term plus independent Brownian motions: is the sum of pair potentials, V(r)+ ^d J(r); the second term has the form of a Kac potential with inverse range . Using diffusive hydrodynamic scaling (spatial scale ^–1, temporal scale ^–2) we obtain, in the limit 0, a diffusive-type integrodifferential equation describing the time evolution of the macroscopic density profile.     

Measurement of the decay constant f(Ds+) using D(s+)-->l+ nu

We measure the decay constant f(Ds+) using the D(s+)-->l+ nu channel, where the l+ designates either a mu+ or a tau+, when the tau+ -->pi+ nu. Using both measurements we find f(Ds+)=274+/-13+/-7 MeV. Combining with our previous determination of f(D+), we compute the ratio f(Ds+)/f(D+)=1.23+/-0.11+/-0.04. We compare with theoretical estimates.     

Impact of atomic force microscopy on interface and colloid science

Since its invention twenty years ago the atomic force microscope (AFM) has become one of the most important tools in colloid and interface science. The reason for this impact is that the AFM allows doing experiments on length, time, force, and energy scales, which are not accessible by any other technique. These experiments can be carried out under natural conditions, for example in liquid environments. In this paper we specify the length and time scales involved, give examples where by using the AFM relevant questions in colloid and interface science have been solved, and we discuss future perspectives.     

On the derivation of Young's equation for sessile drops: nonequilibrium effects due to evaporation

Sessile liquid drops have a higher vapor pressure than planar liquid surfaces, as quantified by Kelvin's equation. In classical derivations of Young's equation, this fact is often not taken into account. For an open system, a sessile liquid drop is never in thermodynamic equilibrium and will eventually evaporate. Practically, for macroscopic drops the time of evaporation is so long that nonequilibrium effects are negligible. For microscopic drops evaporation cannot be neglected. When a liquid is confined to a closed system, real equilibrium can be established. Experiments on the evaporation of water drops confirm the calculations.