PYTHIA status report
Recent improvements in the PYTHIA event generator are summarized: new hard subprocesses, γ*γ* physics, QCD final-state showers, and more.
The Lund Model
Preface 1. Relativistic kinematics, electromagnetic fields and the method of virtual quanta 2. The harmonic oscillator and the quantum field 3. The vacuum as a dielectric medium and renormalisation 4. Deep inelastic scattering and the parton model 5. The classical motion of the massless relativistic string 6. The decay kinematics of the massless relativistic string 7. A stochastic process for string decay 8. The properties of the Lund model fragmentation formulae: external part formulas 9. The internal part fragmentation formulae and their relations to the unitarity equations of Regge theory 10. The dynamical analogues of the Lund model fragmentation formulae 11. Flavour and transverse momentum generation, and the vector to pseudoscalar meson ratio 12. Heavy quark fragmentation and Baryon production 13. The Hanbury-Brown-Twiss-effect and polarisation in the Lund model 14. The Lund gluon model, the kinematics and the decay properties 15. Gluon emission via the Bremsstrahlung process 16. Multigluon emission, the dipole moment and parton coherence cascade models 17. The lambda measure in the leading log, and the modified lead log approximation of perturbative QCD 18. The parton model and QCD 19. Inelastic lepto-production in the Lund model, the soft radiation model and heretical structure functions 20. Hadronic interaction models References Index.
Experimental energy barriers to anions transporting through nanofiltration membranes.
Environmentally relevant contaminants fluoride, chloride, nitrate, and nitrite face Arrhenius energy barriers during transport through nanofiltration (NF) membranes. The energy barriers were quantified using crossflow filtration experiments and were in the range of 7-17 kcal·mol(-1), according to ion type and membrane type (Filmtec NF90 and NF270). Fluoride faced a comparatively high energy barrier for both membranes. This can be explained by the strong hydration energy of fluoride rather than other ion properties such as bare ion radius, fully hydrated radius, Stokes radius, diffusion coefficient, or ion charge. The energy barrier for fluoride decreased with pressure, indicating an impact of directional force on energy barriers. The influence of temperature-induced pore radius variability and viscosity on energy barriers was considered. The novel link between energy barriers and ion properties emphasizes the importance of ion hydration and/or partial dehydration mechanisms in determining transport in NF.