We study the collaborative transport planning for two autonomous business units of Fritom, a Dutch logistics service provider. This difficult planning problem does not fit any existing type of vehicle routing problem proposed in the academic literature; therefore, we define a new problem class, the generalized pickup and delivery problem. We also propose and evaluate methods to structure and improve Fritom's existing collaborative transport planning process. Using an extensive real-world data set from Fritom, our experiments show that our proposed methods significantly outperform Fritom's collaborative planning approach in total travel distance. We formulate managerial recommendations for Fritom and describe the implementation process for these recommendations. Finally, we present several recommendations for future research.

When an alternative fuel is introduced, the infrastructure through which that fuel is made available to the market is often underdeveloped. Transportation service providers relying on such infrastructures are unlikely to adopt alternative fuel vehicles as it may impose long detours for refueling. In this paper, we design and apply a new solution approach to derive minimum infrastructure requirements, in terms of the number of alternative fuel stations. The effectiveness of our approach is demonstrated by applying it to the case of introducing liquefied natural gas (LNG) as a transportation fuel in The Netherlands. From this case, we learn that, depending on the driving range of the LNG trucks and the size of area on which those trucks operate, a minimum of 5-12 LNG fuel stations is necessary to render LNG trucks economically and environmentally beneficial.

The European Union aims for a 40% reduction in greenhouse gas emissions by 2030, compared to 1990 levels, and recognizes the opportunities of Liquefied Natural Gas (LNG) as an alternative fuel for transportation to reach this goal. The lack of a mature supply chain for LNG as a fuel results in a need to invest in new (satellite) terminals, bunker barges and tanker trucks. This network design problem can be defined as a Two-Echelon Capacitated Location Routing Problem with Split Deliveries (2E-CLRPSP). An important feature of this problem is that direct deliveries are allowed from terminals, which makes the problem much harder to solve than the existing location routing literature suggests. In this paper, we improve the performance of a hybrid exact algorithm and apply our algorithm to a real-world network design problem related to the expansion of the European supply chain for LNG as a fuel. We show that satellite terminals and bunker barges become an interesting option when demand for LNG grows and occurs further away from the import terminal. In those situations, the large investments associated with LNG satellites and bunker barges are offset by reductions in operational costs of the LNG tanker trucks.

In this paper, we study a novel stochastic inventory management problem that arises in storage and refueling facilities for Liquefied Natural Gas (LNG) as a transportation fuel. In this inventory problem, the physio-chemical properties of LNG play a key role in the design of inventory policies. These properties are: (1) LNG suffers from both quantity decay and quality deterioration and (2) the quality of on-hand LNG can be upgraded by mixing it with higher-quality LNG. Given that LNG quality can be upgraded, an inventory control policy for this problem needs to consider the removal of LNG as a decision variable. We model and solve the problem by means of a Markov Decision Process (MDP) and study the structural characteristics of the optimal policy. The insights obtained in the analysis of the optimal policy are translated into a simple, though effective, inventory control policy in which actions (i.e., replenishment and/or removal) are driven by both the quality and the quantity of the inventories. We assess the performance of our policy by means of a numerical study and show that it performs close to optimal in many numerical instances. The main conclusion of our study is that it is important to take quality into consideration when design inventory control policies for LNG, and that the most effective way to cope with quality issues in an LNG inventory system involves both the removal and the replenishment of inventories.

ResumenSe presenta el diseño y evaluación experimental de seis mezcladores para un quemador de premezcla de 1,5 kW de potencia térmica, usando gas licuado de petróleo como gas combustible. Se realiza una investigación centrada en los parámetros de diseño del mezclador para mejorar el desempeño de la cocina doméstica a gas en el proceso de combustión. Esto se manifiesta en el rendimiento térmico y las emisiones generadas. Se presenta el análisis de los mezcladores de aire-gas combustible a diferentes condiciones para determinar la más conveniente según el modelo. Se propone el desarrollo de una cocina de alta eficiencia y bajas emisiones, entregando a la entidad competente un proyecto de norma técnica en rendimiento térmico de cocinas domésticas a gas licuado de petróleo a nivel del mar. Palabras clave: quemadores domésticos de GLP; rendimiento térmico; emisiones, diseño de cocinas Design and Evaluation of Mixers in Domestic Burner using Liquiefied Petroleum Gas AbstractThe design and experimental evaluation of six mixers for a premix burner of 1,5 kW thermal power, using liquefied petroleum gas as fuel gas is presented. An investigation focused on the design parameters of the mixer to improve the performance of the domestic gas cooker in the combustion process is developed. This is manifested in the thermal performance and the emissions generated, so the analysis of the air-fuel gas mixers is presented for different conditions to determine the most suitable according to the model. The construction of a high efficiency and low emissions cooker is proposed, delivering to the competent entity a project of a technical standard on thermal performance of domestic cookers with liquefied petroleum gas at sea level.