28 research outputs found
Synchronizing inventory and transport within supply chain management
The problem considers synchronized optimization of inventory and transport, and focuses on producer-distributor relations. Particular attention is paid to developing a mathematical model and an optimization problem that can be used to minimize the overall distribution cost by an appropriate placement of warehouses and cross-docking points. Solutions to this problem are explored using genetic algorithms and ideas from graph/network theory.
Note: there are three separate reports contained within the uploaded .pdf file
Dynamical simulations of polaron transport in conjugated polymers with the inclusion of electron-electron interactions
Dynamical simulations of polaron transport in conjugated polymers in the
presence of an external time-dependent electric field have been performed
within a combined extended Hubbard model (EHM) and Su-Schrieffer-Heeger (SSH)
model. Nearly all relevant electron-phonon and electron-electron interactions
are fully taken into account by solving the time-dependent Schr\"{o}dinger
equation for the -electrons and the Newton's equation of motion for the
backbone monomer displacements by virtue of the combination of the adaptive
time-dependent density matrix renormalization group (TDDMRG) and classical
molecular dynamics (MD). We find that after a smooth turn-on of the external
electric field the polaron is accelerated at first and then moves with a nearly
constant velocity as one entity consisting of both the charge and the lattice
deformation. An ohmic region (3 mV/ 9
mV/) where the stationary velocity increases linearly with the
electric field strength is observed for the case of =2.0 eV and =1.0 eV.
The maximal velocity is well above the speed of sound. Below 3 mV/
the polaron velocity increases nonlinearly and in high electric fields with
strength 10.0 mV/ the polaron will become unstable and
dissociate. The relationship between electron-electron interaction strengths
and polaron transport is also studied in detail. We find that the the on-site
Coulomb interactions will suppress the polaron transport and small
nearest-neighbor interactions values are also not beneficial to the
polaronic motion while large values favor the polaron transport