Reverse logistics practices for recovering mobile phones in Spain

The main objective of this article is to characterize the reverse logistics system for mobile phones in Spain. The study includes the characterization of the different actors involved in the reverse logistics system and the description of the most common logistics practices in the sector. We will also opose alternative practices for managing this complex reverse logistics system and finally, we analyse the challenges of the current reverse logistics model. Some alternatives for the current model are location of reception points for end-of-use mobiles, the need to legislate the secondhand mobile phone market, and the location of the necessary recycling centres according to current legislation.

Increasing the accuracy of positive displacement meters for the measurement of volume in liquid hydrocarbon logistics

Accuracy in the liquid hydrocarbons custody transfer is mandatory because it has a great economic impact. By far the most accurate meter is the positive displacement (PD) meter. Increasing such an accuracy may adversely affect the cost of the custody transfer, unless simple models are developed in order to lower the cost, which is the purpose of this work. PD meter consists of a fixed volume rotating chamber. For each turn a pulse is counted, hence, the measured volume is the number of pulses times the volume of the chamber. It does not coincide with the real volume, so corrections have to be made. All the corrections are grouped by a meter factor. Among corrections highlights the slippage flow. By solving the Navier-Stokes equations one can find an analytical expression for this flow. It is neither easy nor cheap to apply straightforward the slippage correction; therefore we have made a simple model where slippage is regarded as a single parameter with dimension of time. The model has been tested for several PD meters. In our careful experiments, the meter factor grows with temperature at a constant pace of 8?10?5?ºC?1. Be warned