Delivery pattern planning in retailing with transport and warehouse workload balancing

Goods from warehouses must be scheduled in advance, prepared, routed, and delivered to shops. At least three systems directly interact within such a process: warehouse workforce scheduling, delivery scheduling, and routing system. Ideally, the whole problem with the preceding inventory management (restocking) would be solved in one optimization pass. In order to make the problem simpler, we first decompose the total problem by isolating the delivery scheduling. Then we connect the optimization model to the rest of the system by workload balancing goal that is a surrogate of coordination and criterion for the system robustness. This paper presents the practical application of top-down discrete optimization that streamlines operations and enables better reactivity to changes in circumstances. We search for repetitive weekly delivery patterns that balance the daily warehouse and transportation utilization in the absence of capacity constraints. Delivery patterns are optimized for the quality criteria regarding specific store-warehouse pair types, with a special focus on fresh food delivery that aims at reducing inventory write-offs due to aging. The previous setup included semimanual scheduling based on templates, historical prototypes, and domain knowledge. We have found that the system augmented with the new automated delivery scheduling system brings an improvement of 3% in the performance measure as well as speed in adjusting to the changes, such was the case with changes in policies during COVID-19 lockdowns

Hydrothermal growth of iron oxide NPs with a uniform size distribution for magnetically induced hyperthermia: Structural, colloidal and magnetic properties

Magnetic iron oxide nanoparticles with a narrow size distribution were synthesized by hydrothermally treating suspensions of iron oxide nanoparticles. Ricinoleic-acid-coated magnetic nanoparticles were co precipitated at room temperature from an aqueous solution of Fe2+/Fe3+ cations by the addition of a base. The presence of the ricinoleic acid on the nanoparticles' surfaces strongly suppressed their growth under the hydrothermal conditions. Because of the strong dependency of the rate of particle growth on their size, the size distribution significantly narrowed during the hydrothermal treatment. The size of the nanoparticles was successfully controlled by the temperature of the synthesis and the amount of ricinoleic acid present in the reaction mixture to between 9 and 30 nm. The presence of the ricinoleic acid on nanoparticles' surfaces enabled the preparation of colloidal suspensions in even moderately polar organic liquids. Measurements of the magnetic properties revealed that the nanoparticles smaller than 14 nm exhibited superparamagnetic behavior and nanoparticles larger than 15 nm displayed single domain ferrimagnetic behavior. The nanoparticles exhibited large values of saturation magnetization of up to 90 emu/g. The strong dependence of the nanoparticles' specific power losses when subjected to an alternating magnetic field on their average size and frequency was demonstrated. The ferrimagnetic nanoparticles showed much higher power losses than the superparamagnetic nanoparticles. (C) 2016 Elsevier B.V. All rights reserved