Kinetic study on the thermal degradation of heavy oil in presence of SBA-15 containing aluminum and cerium

In research for materials that can be applied in processing heavy oil (petroleum), this work proposes to synthesize mesoporous heterogeneous catalysts, type SBA-15, with the addition of cerium metal and aluminum. These catalysts were characterized by X-ray diffraction, scanning electron micrographs coupled to energy dispersive spectrometry, spectroscopy in the infrared region by Fourier transform, N₂ adsorption and desorption and thermal analysis-thermogravimetry. Thermal tests were performed to evaluate the thermal and catalytic degradation process with a sample of heavy oil (°API = 14). Through the non-isothermal kinetic model of Ozawa Flynn Wall (OFW) some parameters for determining the apparent activation energy of decomposition were obtained. The petroleum with 12% of Ce₅Al₅₀SBA-15 showed a catalytic activity for this material. It has been seen that there was a decrease in the Ea in model free of the order from 89.0 to 104.9 kJ mol^?1 in α = 50% ± 10%, and it was repeated from the first percentage until the last showing performance of Ce₅Al₅₀SBA-15 as a catalyst.     

Lagrangian relaxation for maximum service in multicast routing with QoS constraints

In this paper, we propose a new variant of the Multicast Routing Problem called Maximum Service in Multicast Routing with Quality of Service constraints applied in the context of vehicular ad hoc networks, for which data must be sent from a root node to a set of terminal nodes. The use of all nodes is not mandatory and each connection between the root and a terminal aims to satisfy the quality of service according to the limits established for each metric. The objective is to maximize the number of serviced terminals according to the network's quality of service metrics. We present an integer programming formulation and four Lagrangian relaxations, to obtain good primal and dual bounds. We also develop a local search applied during the resolution of the Lagrangian relaxations. These methodologies were subjected to computational experiments with a set of 40 instances generated with characteristics of vehicular ad hoc networks. Statistical analyses were performed to compare the performance between methodologies, where the model achieved optimal values for 29 instances, and the Lagrangian relaxations rendered competitive bounds, especially for large instances.