Multiplicity Fluctuations and Bose-Einstein Correlations in DIS at HERA

Results of the recent studies of the multiplicity fluctuations and Bose-Einstein correlations (BEC) in deep-inelastic scattering (DIS) at large Q$^2$ are reviewed. The measurements were done with the ZEUS detetor at HERA.Comment: 4 pages, 3 figures in eps, talk given at XXXI International Symposium on Multiparticle Dynamics, Sept 1-7, 2001, Datong China. URL http://202.114.35.18

Parton Branching in Color Mutation Model

The soft production problem in hadronic collisions as described in the eikonal color mutation branching model is improved in the way that the initial parton distribution is treated. Furry branching of the partons is considered as a means of describing the nonperturbative process of parton reproduction in soft interaction. The values of all the moments, and $C_q$, for q=2,...,5, as well as their energy dependences can be correctly determined by the use of only two parameters.Comment: 8 pages (LaTeX) + 2 figures (ps files), submitted to Phys. Rev.

Enhancement of vortex pinning in superconductor/ferromagnet bilayers via angled demagnetization

We use local and global magnetometry measurements to study the influence of magnetic domain width w on the domain-induced vortex pinning in superconducting/ferromagnetic bilayers, built of a Nb film and a ferromagnetic Co/Pt multilayer with perpendicular magnetic anisotropy, with an insulating layer to eliminate proximity effect. The quasi-periodic domain patterns with different and systematically adjustable width w, as acquired by a special demagnetization procedure, exert tunable vortex pinning on a superconducting layer. The largest enhancement of vortex pinning, by a factor of more than 10, occurs when w ~ 310 nm is close to the magnetic penetration depth.Comment: 5 pages, 3 figures, accepted to Phys. Rev. B, Rapid Communication

Single inclusive pion pT-spectra in proton-proton collisions at sqrt(s) = 22.4GeV: data versus perturbative QCD calculations

We compare the inclusive transverse momentum spectra of single pions above pT = 3 GeV/c measured in proton-proton (p-p) collisions at sqrt(s) = 21.7 - 23.8 GeV, with next-to-leading order (NLO) perturbative QCD (pQCD) predictions using recent parametrizations of the parton densities and parton-to-pion fragmentation functions. Although the dependence on the theoretical scales is large, the calculations can reproduce the experimental results both in magnitude and shape. Based on the existing data and on a pQCD $\sqrt{s}$-rescaling of the measured spectra, we provide a practical parametrization of the baseline p-p pion transverse momentum spectrum to be compared to nucleus-nucleus collisions data at sqrt(s_NN) = 22.4 GeV.Comment: 16 pages, 7 figure

Superconductor-insulator transition in Josephson junction chains by quantum Monte-Carlo

We study the zero-temperature phase diagram of a dissipationless and disorder-free Josephson junction chain. Namely, we determine the critical Josephson energy below which the chain becomes insulating, as a function of the ratio of two capacitances: the capacitance of each Josephson junction and the capacitance between each superconducting island and the ground. We develop an imaginary-time path integral Quantum Monte-Carlo algorithm in the charge representation, which enables us to efficiently handle the electrostatic part of the chain Hamiltonian. We find that a large part of the phase diagram is determined by anharmonic corrections which are not captured by the standard Kosterlitz-Thouless renormalization group description of the transition

Query Optimization by Indexing in the ODRA OODBMS

We present features and samples of use of the index optimizer module which has been implemented and tested in the ODRA prototype system. The ODRA index implementation is based on linear hashing and works in a scope of a standalone database. The solution is adaptable to distributed environments in order to optimally utilize data grid computational resources. The implementation consists of transparent optimization, automatic index updating and management facilities

Intermittency and Exotic Channels

It is pointed out that accurate measurements of short-range two-particle correlations in like-charge $K\pi$ and in $\pi^ 0\pi^ 0$ channels should be very helpful in determining the origin of the \lq\lq intermittency\rq\rq\ phenomenon observed recently for the like-charge pion pairs.Comment: 5 p., plain tex, preprint T94/078(Saclay), LPTHE 94/58(Orsay

Uniaxial compression of 3D printed samples with voids: laboratory measurements compared with predictions from Effective Medium Theory

3D printing technology offers the possibility of producing synthetic samples with accurately defined microstructures. As indicated by effective medium theory (EMT), the shapes, orientations, and sizes of voids significantly affect the overall elastic response of a solid body. By performing uniaxial compression tests on twenty types of 3D-printed samples containing voids of different geometries, we examine whether the measured effective elasticities are accurately predicted by EMT. To manufacture the sample, we selected printers that use different technologies; fused deposition modelling (FDM), and stereolithography (SLA). We show how printer settings (FDM case) or sample cure time (SLA case) affect the measured properties. We also examine the reproducibility of elasticity tests on identically designed samples. To obtain the range of theoretical predictions, we assume either uniform strain or uniform stress. Our study of over two hundred samples shows that measured effective elastic moduli can fit EMT predictions with an error of less than 5% using both FDM and SLA methods if certain printing specifications and sample design considerations are taken into account. Notably, we find that the pore volume fraction of the designed samples should be above 1% to induce a measurable softening effect, but below 5% to produce accurate EMT estimations that fit the measured elastic properties of the samples. Our results highlight both the strengths of EMT for predicting the effective properties of solids with low pore fraction volume microstructural configurations, and the limitations for high porosity microstructures.Comment: 43 pages, 19 figs, 9 table