There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

THE DESIGN AND ANALYSIS OF EXPERIMENTS. By Oscar Kempthorne. New York, John Wiley and Sons, Inc., 1952. 631 pp. $8.50. This book by a teacher of statistics (as well as a consultant for \"experimenters\") is a comprehensive study of the philosophical background for the statistical design of experiment. It is necessary to have some facility with algebraic notation and manipulation to be able to use the volume intelligently. The problems are presented from the theoretical point of view, without such practical examples as would be helpful for those not acquainted with mathematics. The mathematical justification for the techniques is given. As a somewhat advanced treatment of the design and analysis of experiments, this volume will be interesting and helpful for many who approach statistics theoretically as well as practically. With emphasis on the \"why,\" and with description given broadly, the author relates the subject matter to the general theory of statistics and to the general problem of experimental inference. MARGARET J. ROBERTSON

The Design and Analysis of Experiments

CO2 conversion covers a wide range of possible application areas from fuels to bulk and commodity chemicals and even to specialty products with biological activity such as pharmaceuticals. In the present review, we discuss selected examples in these areas in a combined analysis of the state-of-the-art of synthetic methodologies and processes with their life cycle assessment. Thereby, we attempted to assess the potential to reduce the environmental footprint in these application fields relative to the current petrochemical value chain. This analysis and discussion differs significantly from a viewpoint on CO2 utilization as a measure for global CO2 mitigation. Whereas the latter focuses on reducing the end-of-pipe problem “CO2 emissions” from todays’ industries, the approach taken here tries to identify opportunities by exploiting a novel feedstock that avoids the utilization of fossil resource in transition toward more sustainable future production. Thus, the motivation to develop CO2-based chemistry does...

Sustainable Conversion of Carbon Dioxide: An Integrated Review of Catalysis and Life Cycle Assessment

Despite being first demonstrated over 160 years ago, and offering significant environmental benefits and high electrical efficiency, it is only in the last two decades that fuel cells have offered a realistic prospect of being commercially viable. The solid oxide fuel cell (SOFC) offers great promise and is presently the subject of intense research activity. Unlike other fuel cells the SOFC is a solid-state device which operates at elevated temperatures. This review discusses the particular issues facing the development of a high temperature solid-state fuel cell and the inorganic materials currently used and under investigation for such cells, together with the problems associated with operating SOFCs on practical hydrocarbon fuels.

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Solid oxide fuel cells

A study is conducted to demonstrate catalytic dehydrogenation of light alkanes on metals and metal oxides. The study provides a complete overview of the materials used to catalyze this reaction, as dehydrogenation for the production of light olefins has become extremely relevant. Relevant factors, such as the specific nature of the active sites, as well as the effect of support, promoters, and reaction feed on catalyst performance and lifetime, are discussed for each catalytic Material. The study compares different catalysts in terms of the reaction mechanism and deactivation pathways and catalytic performance. The duration of the dehydrogenation step depends on the heat content of the catalyst bed, which decreases rapidly due to the endothermic nature of the reaction. Part of the heat required for the reaction is introduced to the reactors by preheating the reaction feed, additional heat being provided by adjacent reactors that are regenerating the coked catalysts.

Catalytic dehydrogenation of light alkanes on metals and metal oxides.

Hydrogen plays an essential role during the in situ assembly of tailored catalytic materials, and serves as key ingredient in multifarious chemical reactions promoted by these catalysts. Despite intensive debate for several decades, the existence and nature of hydrogen-involved mechanisms - such as hydrogen-spillover, surface migration - have not been unambiguously proven and elucidated up to date. Here, Pt-Ga alloy formation is used as a probe reaction to study the behavior and atomic transport of H and Ga, starting from Pt nanoparticles on hydrotalcite-derived Mg(Ga)(Al)Ox supports. In situ XANES spectroscopy, time-resolved TAP kinetic experiments, HAADF-STEM imaging and EDX mapping are combined to probe Pt, Ga and H in a series of H2 reduction experiments up to 650 °C. Mg(Ga)(Al)Ox by itself dissociates hydrogen, but these dissociated hydrogen species do not induce significant reduction of Ga(3+) cations in the support. Only in the presence of Pt, partial reduction of Ga(3+) into Ga(δ+) is observed, suggesting that different reaction mechanisms dominate for Pt- and Mg(Ga)(Al)Ox-dissociated hydrogen species. This partial reduction of Ga(3+) is made possible by Pt-dissociated H species which spillover onto non-reducible Mg(Al)Ox or partially reducible Mg(Ga)(Al)Ox and undergo long-range transport over the support surface. Moderately mobile Ga(δ+)Ox migrates towards Pt clusters, where Ga(δ+) is only fully reduced to Ga(0) on condition of immediate stabilization inside Pt-Ga alloyed nanoparticles.

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The role of hydrogen during Pt–Ga nanocatalyst formation

Kinetics of chemical processes: From molecular to industrial scale

An alternative method for parameter identification from temperature programmed reduction (TPR) data

Electrocatalytic conversion of metane in a cell with a solid oxygen conducting electrolyte: CH 4 , Ni|0.9ZrO 2 + 0.1Y 2 O 3 |Pt + PrO 2 , air was studied at the temperature range 750°C–850°C. The Ni electrode was found to be an active electrode-catalyst for partial oxidation of CH 4 to syngas with the concentration ratio [H 2 ] : [CO]≈2 . The CH 4 conversion and CO selectivity attained 85%–95% and 90%–95%, respectively, at 800°C–850°C. Under these conditions the Ni electrode-catalyst was stable to coking and had a negative value of electrode potential with respect to an air counter electrode. The direct partial oxidation mechanism was shown to be the most probable for the electrocatalytic conversion of CH 4 to syngas.

Electrocatalytic conversion of methane to syngas over Ni electrode in a solid oxide electrolyte cell

Studies of carbon monoxide oxidation on an Ag-25 at% Pd alloy electrode in a cell with a solid oxygen-conducting electrolyte - CO+O2, Ag-Pd | 0.9 ZrO2+0.1Y2O3 | Pt+PrO2-x, air - were carried out. XRD, SEM and XPS techniques were used for characterisation of the Ag-Pd alloy electrode. The non-Faradaic effect of electrochemical oxygen pumping on the rate of carbon monoxide oxidation was demonstrated. The induced change in the reaction rate at cathodic polarization of the Ag-Pd alloy electrode was an order of magnitude higher than the rate of oxygen pumping from the reaction zone through the electrolyte. The observed phenomenon was qualitatively explained on the base of a chain reaction mechanism involving electrochemically generated oxygen species.

Vladimir Galvita

Papers

The role of hydrogen during Pt–Ga nanocatalyst formation

Kinetics of chemical processes: From molecular to industrial scale

An alternative method for parameter identification from temperature programmed reduction (TPR) data

Electrocatalytic conversion of methane to syngas over Ni electrode in a solid oxide electrolyte cell

Non-Faradaic catalysis : the case of CO oxidation over Ag-Pd alloy electrode in a solid oxide electrolyte cell