Preparation, performances and reaction mechanism for the synthesis of H2O2 from H2 and O2 based on palladium membranes

Taking a critically informed approach, this innovative text examines emerging approaches to social procurement within the context of New Public Government (NPG), and examines the practices of social procurement across Europe, North America and Australia. Considering both the possibilities and limitations of social procurement, and the types of value it can generate, this book also provides empirically driven insights into the practicalities of 'triple bottom line' procurement, the related challenges of measuring social value and the management of both the strategic and operational dimensions of procurement processes. As such it will be invaluable reading for all those interest in social services, public governance and social enterprise

Catalysis on nano-carbon materials: Going where to?

This introductory contribution to the special issue of Catalysis Today is dedicated to selected contributions presented at the Carbocat-IV (Carbon for Catalysis) Symposium held in Dalian (China) on November 7–10 (2010). The introduction first shortly overviews the main reasons for the interest on carbon materials for catalysis and the elements of novelty discussed on the contributions of this issue, and then provide a concise outline of the general trends and developments in this field to give a glimpse on the progresses in the field, and on the perspectives of this exciting area of catalysis

Use of Pt/CexZr1-xAl2O3 as Advanced Catalyst for Hydrogen Peroxide Thrusters

The capability of different Pt/Ce0.6Zr0.4/Al2O3 catalytic systems of effectively decomposing H2O2 has been studied in view of their application to monopropellant thrusters. BET surface area measurements, X-Ray Diffractometry (XRD) and Scanning Electron Microscopy (SEM) have been used together with catalytic tests in order to evaluate the advantages of using CeO2-ZrO2 mixed oxide solid solution as an alternative to current three ways catalysts (TWCs). From the assessment of alternative solutions, a Pt/Ce0.6Zr0.4/Al2O3 catalyst suitable to effectively decompose H2O2 has been identified. SEM-EDX analyses ruled out the occurrence of phase segregation and selective deposition of Pt on Zr during the catalyst preparation. No changes in the crystalline arrangement of the catalyst samples after H2O2 decomposition have been detected by XRD measurements, except for a slight crystallization or grain size growth as a consequence of the high temperatures experienced during the reaction...

Performance Evaluation of Components Using a Granularity-based Interface Between Real-Time Calculus and Timed Automata

To analyze complex and heterogeneous real-time embedded systems, recent works have proposed interface techniques between real-time calculus (RTC) and timed automata (TA), in order to take advantage of the strengths of each technique for analyzing various components. But the time to analyze a state-based component modeled by TA may be prohibitively high, due to the state space explosion problem. In this paper, we propose a framework of granularity-based interfacing to speed up the analysis of a TA modeled component. First, we abstract fine models to work with event streams at coarse granularity. We perform analysis of the component at multiple coarse granularities and then based on RTC theory, we derive lower and upper bounds on arrival patterns of the fine output streams using the causality closure algorithm. Our framework can help to achieve tradeoffs between precision and analysis time.Comment: QAPL 201

Human Computation and Convergence

Humans are the most effective integrators and producers of information, directly and through the use of information-processing inventions. As these inventions become increasingly sophisticated, the substantive role of humans in processing information will tend toward capabilities that derive from our most complex cognitive processes, e.g., abstraction, creativity, and applied world knowledge. Through the advancement of human computation - methods that leverage the respective strengths of humans and machines in distributed information-processing systems - formerly discrete processes will combine synergistically into increasingly integrated and complex information processing systems. These new, collective systems will exhibit an unprecedented degree of predictive accuracy in modeling physical and techno-social processes, and may ultimately coalesce into a single unified predictive organism, with the capacity to address societies most wicked problems and achieve planetary homeostasis.Comment: Pre-publication draft of chapter. 24 pages, 3 figures; added references to page 1 and 3, and corrected typ

Interfacial Chemistry in the Electrocatalytic Hydrogenation of CO_{2} over C-Supported Cu-Based Systems

Operando soft and hard X-ray spectroscopic techniques were used in combination with plane-wave density functional theory (DFT) simulations to rationalize the enhanced activities of Zn-containing Cu nanostructured electrocatalysts in the electrocatalytic CO2 hydrogenation reaction. We show that at a potential for CO2 hydrogenation, Zn is alloyed with Cu in the bulk of the nanoparticles with no metallic Zn segregated; at the interface, low reducible Cu(I)-O species are consumed. Additional spectroscopic features are observed, which are identified as various surface Cu(I) ligated species; these respond to the potential, revealing characteristic interfacial dynamics. Similar behavior was observed for the Fe-Cu system in its active state, confirming the general validity of this mechanism; however, the performance of this system deteriorates after successive applied cathodic potentials, as the hydrogen evolution reaction then becomes the main reaction pathway. In contrast to an active system, Cu(I)-O is now consumed at cathodic potentials and not reversibly reformed when the voltage is allowed to equilibrate at the open-circuit voltage; rather, only the oxidation to Cu(II) is observed. We show that the Cu-Zn system represents the optimal active ensembles with stabilized Cu(I)-O; DFT simulations rationalize this observation by indicating that Cu-Zn-O neighboring atoms are able to activate CO2, whereas Cu-Cu sites provide the supply of H atoms for the hydrogenation reaction. Our results demonstrate an electronic effect exerted by the heterometal, which depends on its intimate distribution within the Cu phase and confirms the general validity of these mechanistic insights for future electrocatalyst design strategies