Vibrational Spectrum of a Platinum Complex of Piroxicam

The infrared and Raman spectra of a platinum complex of the antiinflammatory drug piroxicam (Pir) and dimethylsulfoxide (DMSO) of composition [PtCl₂Pir(DMSO)] were recorded and briefly discussed on the basis of its structural characteristics. The metal-to-ligand vibrations are analyzed in detail.     

Untersuchungen von Mischvorgängen bei der Herstellung technischer Kohleprodukte unter Anwendung der Methode der radioaktiven Markierung

Es werden die Ergebnisse von Mischverfahren für Kohlepulver, Pech und andere Komponenten mitgeteilt, die unter Markierungen mit ²⁴Na-Benzoat im Laboratorium (Mischvolumen etwa 1 Liter) und im Betrieb (Mischvolumen etwa 100 Liter) durchgführt wurden. Die Experimente dienten dem Vergleich der Vergleich der Wirksamkeit verschiedener Mischmaschinen, der Ermittlung optimaler Mischzeiten und der Bestimmung des Verhaltens einzelner Komponenten beim Mischprozeβ. Dis mittels Szintillationszählung gewonnenen Meβwerte werden dabei mit einem Ergebnisdrucker registriert und mit Hilfa einer Rechenanlage mathematisch ausfewertet.     

Phase transition to hyperon matter in neutron stars

Recent progress in the understanding of the high density phase of neutron stars advances the view that a substantial fraction of the matter consists of hyperons. The possible impacts of a highly attractive interaction between hyperons on the properties of compact stars are investigated. We find that a hadronic equation of state with hyperons allows for a first order phase transition to hyperonic matter. The corresponding hyperon stars can have rather small radii of R approximately equal 8 km.     

Exclusive measurement of the pp --> pppi(+)pi(-) reaction near threshold

The pp-->pp pi(+) pi(-) reaction has been measured exclusively near threshold at CELSIUS. The total cross sections are nearly an order of magnitude lower than expected from previous inclusive measurements. The differential cross sections reveal pp-->pp(*)(1440)-->pp sigma = pp(pi(+)pi(-))(I = l = 0) as the dominant process as well as significant contributions from p(*)-->Delta(++)pi(-)-->psigma. The observed anisotropy in the proton angular dependence is consistent with heavy-meson exchange. In the invariant mass spectra, no narrow structures of statistical relevance (3sigma) are found.     

Production of charged pions, kaons and antikaons in relativistic C + C and C + Au collisions

Production cross-sections of charged pions, kaons and antikaons have been measured in C+C and C+Au collisions at beam energies of 1.0 and 1.8 AGeV for different polar emission angles. The kaon and antikaon energy spectra can be described by Boltzmann distributions whereas the pion spectra exhibit an additional enhancement at low energies. The pion multiplicity per participating nucleon M(π⁺)/<A _part> is a factor of about 3 smaller in C+Au than in C+C collisions at 1.0 AGeV whereas it differs only little for the C and the Au target at a beam energy of 1.8 AGeV. The K⁺ multiplicities per participating nucleon M(K⁺)/ <A _part> are independent of the target size at 1 AGeV and at 1.8 AGeV. The K^- multiplicity per participating nucleon M(K^-)/ <A _part> is reduced by a factor of about 2 in C+Au as compared to C+C collisions at 1.8 AGeV. This effect might be caused by the absorption of antikaons in the heavy target nucleus. Transport model calculations underestimate the K^-/K⁺ ratio for C+C collisions at 1.8 AGeV by a factor of about 4 if in-medium modifications of K-mesons are neglected. Received: 10 December 1999 / Accepted: 14 November 2000     

Dependence of fracture stress upon diameter in strong polymeric fibers

The axial and radial dimensions of a fiber are known to be key factors with respect to the mechanical stress necessary to promote failure, this being known as the size effect. Usually different methods are used to quantify the two types of size effects: Linear elastic fracture mechanics (lefm) and related schemes provide the theoretical basis for the effect of diameter variability upon strength whereas statistical theories, generally based upon the Weibull probability distribution combined with the weakest-link theorem, describe length effects. Here we show that simple modifications of the classical Poisson/Weibull form yield a new failure probability function which provides a more adequate explanation for diameter effects on strength in polydiacetylene fibers, and also resolves in a satisfactory way a current problematic issue inherent to the Weibull/weakest-link model. A maximum likelihood estimation procedure is presented for the evaluation of the most appropriate parameters of the proposed failure probability function.     

Numerical study of a stochastic particle algorithm solving a multidimensional population balance model for high shear granulation

This paper is concerned with computational aspects of a multidimensional population balance model of a wet granulation process. Wet granulation is a manufacturing method to form composite particles, granules, from small particles and binders. A detailed numerical study of a stochastic particle algorithm for the solution of a five-dimensional population balance model for wet granulation is presented. Each particle consists of two types of solids (containing pores) and of external and internal liquid (located in the pores). Several transformations of particles are considered, including coalescence, compaction and breakage. A convergence study is performed with respect to the parameter that determines the number of numerical particles. Averaged properties of the system are computed. In addition, the ensemble is subdivided into practically relevant size classes and analysed with respect to the amount of mass and the particle porosity in each class. These results illustrate the importance of the multidimensional approach. Finally, the kinetic equation corresponding to the stochastic model is discussed.