Highly selective synthesis of 2‐butoxy ethanol over Mg/Al/V mixed oxides catalysts derived from hydrotalcites

The catalytic activity of a series of mixed oxides obtained by the thermal decomposition of hydrotalcite‐like precursors was assessed for the alkoxylation of n-butanol with ethylene oxide. The calcination products of a decavanadate intercalated magnesium–aluminium layered double hydroxide were shown to possess extremely high activity for the alkoxylation reaction achieving up to 100% conversion in batch reaction. In all cases, the catalysts exhibit a much higher selectivity towards the monoglycol adduct than that obtained with the industrial catalyst. This revised version was published online in July 2006 with corrections to the Cover Date.     

Conditioned Alarm Behavior in Fathead Minnows (Pimephales promelas) Resulting from Association of Chemical Alarm Pheromone with a Nonbiological Visual Stimulus

Fathead minnows (Pimephales promelas) adopt antipredator (alarm) behavior when they detect alarm pheromone released from an injured conspecific. This is an adaptive response since alarm pheromone is generally released only in the context of a predation event. Alarm reactions may also occur in response to chemical and visual stimuli that minnows learn to associate with release of alarm pheromone. Here, we tested if fathead minnows can learn to associate a nonbiological, visual stimulus with predation risk. Minnows were simultaneously exposed to red light and conspecific alarm pheromone, inducing an alarm reaction. When retested using red light alone, small shoals of minnows displayed an antipredator response: dashing movements and disorganized swimming followed by decreased height in the water column and increased shoal cohesion. This resulted from a single-trial exposure to the combined cues and demonstrates a robust ecological mechanism by which minnows learn to recognize indicators of predation risk that may vary in space and time. However, learning to associate risk with biologically irrelevant stimuli may be an ecological liability. How minnows discern between relevant and irrelevant stimuli in nature is not known.     

Zwitterionic metallocenes via reactions of organozirconocenes with highly electrophilic perfluorophenyl substituted boranes

The highly electrophilic boranes HB(C₆F₅)₂ and B(C₆F₅)₃ are effective reagents for generating a variety of zwitterionic olefin polymerization catalysts. The former borane can be used to incorporate Lewis acid activators into ancillary ligand structures via hydroboration of pendant olefinic functions; alternatively, direct reaction with simple organozirconocenes can lead to a family of hydridoborate stabilized girdle-type zwitterions where charge separation is minimal. The ethylene polymerization activity of these compounds is, in general, poor by virtue of the tight intramolecular ion pairing. More active zwitterionic catalysts can be generated through reaction of B(C₆F₅)₃ with suitable organozirconium pre-catalysts. The solution and solid state structures of several of these compounds are discussed, highlighting the various mechanisms of stabilization found in the catalyst structures. This revised version was published online in June 2006 with corrections to the Cover Date.     

Evolution of a Materials Data Infrastructure

The field of materials science and engineering is writing a new chapter in its evolution, one of digitally empowered materials discovery, development, and deployment. The 2008 Integrated Computational Materials Engineering (ICME) study report helped usher in this paradigm shift, making a compelling case and strong recommendations for an infrastructure supporting ICME that would enable access to precompetitive materials data for both scientific and engineering applications. With the launch of the Materials Genome Initiative in 2011, which drew substantial inspiration from the ICME study, digital data was highlighted as a core component of a Materials Innovation Infrastructure, along with experimental and computational tools. Over the past 10 years, our understanding of what it takes to provide accessible materials data has matured and rapid progress has been made in establishing a Materials Data Infrastructure (MDI). We are learning that the MDI is essential to eliminating the seams between experiment and computation by providing a means for them to connect effortlessly. Additionally, the MDI is becoming an enabler, allowing materials engineering to tie into a much broader model-based engineering enterprise for product design.     

Synthesis,characterization, and thermal behaviors of tannin stearates prepared from quebracho and pine bark extracts

Reported is the preparation of various condensed tannin stearates and the associated chemical characterization and thermal properties of these products. Stearate esters of condensed tannins from both quebracho and pine bark extracts were prepared in generally high, isolated yields from reaction with stearic acid chloride. Tannin esterification was confirmed by both Fourier transform infrared and nuclear magnetic resonance (NMR), and the average degree of stearate substitution was calculated from ¹H‐NMR analysis. Product degree of substitution (DS) was observed to proportionately increase with higher stearic acid chloride ratio with maximum DS values of 4.0 and 5.1 achieved for quebracho and pine tannins, respectively. Thermal analysis revealed that tannin stearate products have increased thermal stability with a degradation onset at significantly higher temperature for those samples possessing relatively greater DS. Analysis using differential scanning calorimetry revealed isolated products to consist of multiple components which exhibit interesting melt behaviors, a likely result from their work up on isolation. However, multiple melt features of the individual components in products were lost on heating to give single, broad melt endotherms due to coalescence of sample components. Furthermore, tannin stearate samples with high DS show relatively greater endothermic melting at higher temperature than those samples with lower DS. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

CO2 process intensification of algae oil extraction to biodiesel

Algae-to-biodiesel processes are hindered by high costs and low energy return on investment.^1,2. Herein, three foci in research improve algae-to-biodiesel processes by: (1) reducing high installation and energy costs in the CO₂ sequestration, cultivation, and harvesting stages; (2) improving oil extraction and biodiesel generation; and (3) increasing utilization of the proteins in lipid-extracted biomass (e.g., for animal feed), as well as the omega-3 fatty acids for nutraceuticals and food supplements. A process is introduced that uses carbon dioxide to aid in all three of these foci. CO₂ is used first in the form of microbubbles to lyse algae cell walls, releasing triglyceride oils. CO₂ also aids with transesterification of these triglycerides using methanol. At low temperatures (353.15–368.15 K) and intermediate pressures (5–10 MMPa), carbon dioxide causes methanol to dissolve partially in the triglyceride phase and triglyceride to dissolve partially in the methanol phase, increasing the transesterification reaction rate. Due to the nondestructive nature of these processes, other metabolites can also be harvested providing improvements in both mass and economic efficiency with an overall sharp reduction in the modeled price of biodiesel.     

Michael J. Mahoney: A retrospective.

Michael Mahoney, who made seminal contributions not only to the Society for the Exploration of Psychotherapy Integration (SEPI) but also to the entire field of psychotherapy, died a tragic death at the age of 60 on May 31, 2006. He published more than 250 scholarly articles and chapters, authored and edited 19 books (one of which was awarded a Citation Classic by the Science Citation Index), edited 4 journals, and served on 23 editorial boards plus numerous guest editorships and advisory boards. His research spanned a tremendous breadth without sacrificing depth. Primarily, however, he inquired into development across the life course, including but not limited to psychotherapy. Initially trained as a behaviorist, he played a significant role in the cognitive revolution in psychology; he was also a leading figure in constructivist psychotherapies. He was a Fellow of the World Academy of Art and Science, as well as a Fellow of the American Association for the Advancement of Science. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A history of numerical modelling of the Wairakei geothermal field

The history of computer modelling of the Wairakei geothermal field is reviewed. It covers the development of lumped-parameter models during the 1970s and then discusses the evolution and first applications of geothermal reservoir simulation techniques. The development of reservoir models of Wairakei at the University of Auckland began in the early 1980s; current models produces good matches against field data. Many future scenarios have been run using the University's models and have been presented at various regulatory hearings. The general conclusion from these scenarios is that Wairakei can continue producing electricity at the current level for at least another 50 years, and if Wairakei is shut down after 100 years of operation it will recover to its pre-exploitation state after a further 300 years.     

Novel models of intertemporal valuation: Past and future outcomes.

Temporal discounting refers to the reduction in the present subjective value of an outcome as a function of the temporal distance to that outcome. Though a number of mathematical models have been proposed to describe this time/value relationship, this search has largely excluded insights from the literature on memory decay. This study examines the utility of memory decay models by comparing the fits of 4 of these models to fits from established temporal discounting models using past and future temporal discounting data. These results (a) suggest that a single model describes valuation of both future and past outcomes; (b) indicate the exponential-power model, from memory decay literature, is statistically superior in fitting discounting data from both past and future outcomes; and (c) support the advancing perspective of the psychological interconnectedness of the future and past. (PsycINFO Database Record (c) 2010 APA, all rights reserved)