Immobilized Ru‐Pincer Complexes for Continuous Gas‐Phase Low‐Temperature Methanol Reforming‐Improving the Activity by a Second Ru‐Complex and Variation of Hydroxide Additives

Ru-pincer complexes were immobilized as supported liquid phase (SLP) materials to allow the methanol reforming reaction as continuous gas phase process. Under reaction conditions, the liquid phase forms from the hydroxide coating. Several hydroxides were screened and CsOH showed highest activity compared to the standard KOH coating. The well-known Ru-pincer complex carbonylchlorohydrido [bis(2-di-i-propylphosphinoethyl)amine]ruthenium(II) is limited in catalyzing the final step of the methanol reforming. Addition of a second complex, having a methylated backbone in the pincer-ligand, could overcome these limitations. Significant enhancement of the overall catalytic activity was observed

DisCoverage: From Coverage to Distributed Multi-Robot Exploration

DisCoverage transfers the well-known solution to the coverage problem to the exploration problem. Essentially, DisCoverage solves the multi-robot exploration problem through a spatially distributed optimization problem. Our contribution is a new objective function for DisCoverage based on the centroidal search. Each robot continuously creates and optimizes the proposed objective function, obtaining a gradient-based control law that leads into unexplored regions. A proof of convergence is given as well as a simulation and a statistical evaluation demonstrating DisCoverage

Improving the Performance of Supported Ionic Liquid Phase Catalysts for the Ultra-Low-Temperature Water Gas Shift Reaction Using Organic Salt Additives

The water gas shift reaction (WGSR) is catalyzed by supported ionic liquid phase (SILP) systems containing homogeneous Ru complexes dissolved in ionic liquids (ILs). These systems work at very low temperatures, that is, between 120 and 160 °C, as compared to >200 °C in the conventional process. To improve the performance of this ultra-low-temperature catalysis, we investigated the influence of various additives on the catalytic activity of these SILP systems. In particular, the application of methylene blue (MB) as an additive doubled the activity. Infrared spectroscopy measurements combined with density functional theory (DFT) calculations excluded a coordinative interaction of MB with the Ru complex. In contrast, state-of-the-art theoretical calculations elucidated the catalytic effect of the additives by non-covalent interactions. In particular, the additives can significantly lower the barrier of the rate-determining step of the reaction mechanism via formation of hydrogen bonds. The theoretical predictions, thereby, showed excellent agreement with the increase of experimental activity upon variation of the hydrogen bonding moieties in the additives investigated

Distributed Multi-Robot Exploration

This dissertation introduces the DisCoverage paradigm. DisCoverage describes a novel scheme for distributed multi-robot exploration. The objective of the multi-robot exploration problem is to explore and map an a priori unknown environment as quick as possible with a group of autonomous robots. DisCoverage solves this problem through effective coordination of the group, such that the robots simultaneously explore different parts of the environment. In contrast to existing approaches, DisCoverage provides a distributed solution to the multi-robot exploration problem: Robots communicate and exchange data only with robots in the respective neighborhood, such that no central coordinating unit is required. As a result, the local data exchange among the robots allows the group to globally act as one team, facilitating robust and efficient exploration of the entire environment

Distributed Multi-Robot Exploration

This dissertation introduces the DisCoverage paradigm. DisCoverage describes a novel scheme for distributed multi-robot exploration. The objective of the multi-robot exploration problem is to explore and map an a priori unknown environment as quick as possible with a group of autonomous robots. DisCoverage solves this problem through effective coordination of the group, such that the robots simultaneously explore different parts of the environment. In contrast to existing approaches, DisCoverage provides a distributed solution to the multi-robot exploration problem: Robots communicate and exchange data only with robots in the respective neighborhood, such that no central coordinating unit is required. As a result, the local data exchange among the robots allows the group to globally act as one team, facilitating robust and efficient exploration of the entire environment