Random packing of spheres in Menger sponge

Random packing of spheres inside fractal collectors of dimension 2 < d < 3 is studied numerically using Random Sequential Adsorption (RSA) algorithm. The paper focuses mainly on the measurement of random packing saturation limit. Additionally, scaling properties of density autocorrelations in the obtained packing are analyzed. The RSA kinetics coefficients are also measured. Obtained results allow to test phenomenological relation between random packing saturation density and collector dimension. Additionally, performed simulations together with previously obtained results confirm that, in general, the known dimensional relations are obeyed by systems having non-integer dimension, at least for d < 3.Comment: 13 pages, 6 figure

Influence of Hydrodynamic Interactions on the Kinetics of Colloidal Particle's Adsorption

The kinetics of irreversible adsorption of spherical particles onto a flat surface is theoretically studied. Previous models, in which hydrodynamic interactions were disregarded, predicted a power-law behavior $t^{-2/3}$ for the time dependence of the coverage of the surface near saturation. Experiments, however, are in agreement with a power-law behavior of the form $t^{-1/2}$. We outline that, when hydrodynamic interactions are considered, the assymptotic behavior is found to be compatible with the experimental results in a wide region near saturation.Comment: 4 pages, 1 figures, Phys. Rev. Lett. (in press

Experimental Studies of Di-Jets in Au + Au Collisions Using Angular Correlations With Respect to Back-to-Back Leading Hadrons

Jet-medium interactions are studied via a multihadron correlation technique ( called 2 + 1 ), where a pair of back-to-back hadron triggers with large transverse momentum is used as a proxy for a di-jet. This work extends the previous analysis for nearly symmetric trigger pairs with the highest momentum threshold of trigger hadron of 5 GeV/c with the new calorimeter-based triggers with energy thresholds of up to 10 GeV and above. The distributions of associated hadrons are studied in terms of correlation shapes and per-trigger yields on each trigger side. In contrast with di-hadron correlation results with single triggers, the associated hadron distributions for back-to-back triggers from central Au + Au data at √ˢᴺᴺ = 200 GeV show no strong modifications compared to d + Au data at the same energy. An imbalance in the total transverse momentum between hadrons attributed to the near-side and away-side of jetlike peaks is observed. The relative imbalance in the Au + Au measurement with respect to d + Au reference is found to increase with the asymmetry of the trigger pair, consistent with the expectation from medium-induced energy-loss effects. In addition, this relative total transverse momentum imbalance is found to decrease for softer associated hadrons. Such evolution indicates that the energy missing at higher associated momenta is converted into softer hadrons

THE PROCESS OF MINES LIQUIDATION AS AN ENVIRONMENTAL, ECONOMIC AND LEGAL PROBLEM

W pracy przeanalizowano problematykę likwidacji kopalń. Proces ten stanowi ostatni etap działalności górniczej. Jego skutkiem powinno być trwałe zminimalizowanie negatywnego oddziaływania środowiskowego byłego zakładu górniczego. Celem pracy było wykazanie złożoności omawianego procesu inwestycyjnego, który nie ogranicza się tylko do problemów środowiskowych. Odnosi się bowiem w całej rozciągłości do kwestii ekonomicznych i prawnych. Jako przykład poprawnie przeprowadzonego procesu likwidacyjnego omówiono działania przeprowadzone w KWK Jan Šverma w Žaclerzu (Republika Czeska). Wydaje się, iż w Polsce pomimo wydatkowania na ten cel znacznych środków nie przykłada się, przynajmniej dotychczas, należytej wagi do kompleksowej realizacji tego rodzaju przedsięwzięć.The article presents issues related to mines liquidation. This process is the last stage of mining activities. As a result the reduce of negative environmental impact should be obtained. The aim of the study was to demonstrate the complexity of this investment process. The last mentioned is not limited to environmental problems and also applies to the economic and legal issues. As an example of properly conducted mine liquidation process activities carried out in the coal mine Jan Šverma (Czech Republic) were presented. It seems that in Poland, despite of disbursement of funds for this purpose, at least so far, due attention isn’t applied to comprehensive implementation of such projects

Beam-Energy-Dependent Two-Pion Interferometry and the Freeze-Out Eccentricity of Pions Measured in Heavy Ion Collisions at the Star Detector

We present results of analyses of two-pion interferometry in Au + Au collisions at root s(NN) = 7.7, 11.5, 19.6, 27, 39, 62.4, and 200 GeV measured in the STAR detector as part of the BNL Relativistic Heavy Ion Collider Beam Energy Scan program. The extracted correlation lengths (Hanbury-Brown-Twiss radii) are studied as a function of beam energy, azimuthal angle relative to the reaction plane, centrality, and transverse mass (m(T)) of the particles. The azimuthal analysis allows extraction of the eccentricity of the entire fireball at kinetic freeze-out. The energy dependence of this observable is expected to be sensitive to changes in the equation of state. A new global fit method is studied as an alternate method to directly measure the parameters in the azimuthal analysis. The eccentricity shows a monotonic decrease with beam energy that is qualitatively consistent with the trend from all model predictions and quantitatively consistent with a hadronic transport model

Charged-to-Neutral Correlation at Forward Rapidity in Au + Au Collisions at √s(NN)=200 GeV

Event-by-event fluctuations of the multiplicities of inclusive charged particles and photons at forward rapidity in Au + Au collisions at √s(NN) = 200 GeV have been studied. The dominant contribution to such fluctuations is expected to come from correlated production of charged and neutral pions. We search for evidence of dynamical fluctuations of different physical origins. Observables constructed out of moments of multiplicities are used as measures of fluctuations. Mixed events and model calculations are used as base lines. Results are compared to the dynamical net-charge fluctuations measured in the same acceptance. A nonzero statistically significant signal of dynamical fluctuations is observed in excess to the model prediction when charged particles and photons are measured in the same acceptance. We find that, unlike dynamical net-charge fluctuation, charge-neutral fluctuation is not dominated by correlation owing to particle decay. Results are compared to the expectations based on the generic production mechanism of pions owing to isospin symmetry, for which no significant

Results on Total and Elastic Cross Sections in Proton–Proton Collisions at √s = 200 GeV

We report results on the total and elastic cross sections in proton-proton collisions at √s = 200 GeV obtained with the Roman Pot setup of the STAR experiment at the Relativistic Heavy Ion Collider (RHIC). The elastic differential cross section was measured in the squared four-momentum transfer range 0.045 ≤ −t ≤ 0.135 GeV². The value of the exponential slope parameter B of the elastic differential cross section dσ/dt ∼ e−Bt in the measured −t range was found to be B = 14.32 ± 0.09 (stat.)+0.13−0.28(syst.) GeV⁻². The total cross section σtot, obtained from extrapolation of the dσ/dt to the optical point at −t = 0, is σtot = 54.67 ± 0.21(stat.)+1.28−1.38(syst.) mb. We also present the values of the elastic cross section σel = 10.85±0.03 (stat.)+0.49−0.41 (syst.) mb, the elastic cross section integrated within the STAR t-range σeldet = 4.05 ± 0.01(stat.)−0.17+0.18(syst.) mb, and the inelastic cross section σinel= 43.82 ± 0.21(stat.)−1.44+1.37(syst.) mb. The results are compared with the world data

Gaussian limits for multidimensional random sequential packing at saturation (extended version)

Consider the random sequential packing model with infinite input and in any dimension. When the input consists of non-zero volume convex solids we show that the total number of solids accepted over cubes of volume $\lambda$ is asymptotically normal as $\lambda \to \infty$. We provide a rate of approximation to the normal and show that the finite dimensional distributions of the packing measures converge to those of a mean zero generalized Gaussian field. The method of proof involves showing that the collection of accepted solids satisfies the weak spatial dependence condition known as stabilization.Comment: 31 page