A designed organic–zeolite hybrid acid–base catalyst

An organic–zeolite hybrid catalyst was synthesised via solid-state impregnation of the zeolite with an amount of melamine corresponding to 20 mol% of the aluminium content. A high density of basic sites is formed in the zeolite. From infrared spectroscopy and TGA measurements we infer that melaminium cations are formed in the zeolite which are highly thermally stable. IR spectroscopic and TGA measurements showed the presence of melaminium after pre-treatment in vacuum at 450 °C. The catalyst exhibited activity in the Knoevenagel condensation reaction between benzaldehyde and ethyl cyanoacetate which is suggested to be promoted by the presence of acid and base sites. The catalyst activity was compared with other known base catalysts including hydrotalcites and magnesium oxide on alumina support.     

Quantifying the stress relaxation modulus of polymer thin films via thermal wrinkling

The viscoelastic properties of polymer thin films can have a significant impact on the performance in many small-scale devices. In this work, we use a phenomenon based on a thermally induced instability, termed thermal wrinkling, to measure viscoelastic properties of polystyrene films as a function of geometric confinement via changes in film thickness. With application of the appropriate buckling mechanics model for incompressible and geometrically confined films, we estimate the stress-relaxation modulus of polystyrene films by measuring the time-evolved wrinkle wavelength at fixed annealing temperatures. Specifically, we use time-temperature superposition to shift the stress relaxation curves and generate a modulus master curve for polystyrene films investigated here. On the basis of this master curve, we are able to identify the rubbery plateau, terminal relaxation time, and viscous flow region as a function of annealing time and temperatures that are well-above its glass transition. Our measurement technique and analysis provide an alternative means to measure viscoelastic properties and relaxation behavior of geometrically confined polymer films.     

An integrated electrochromic nanoplasmonic optical switch

We demonstrate an electrochemically driven optical switch based on absorption modulation of surface plasmon polaritons (SPPs) propagating in a metallic nanoslit waveguide containing nanocrystals of electrochromic Prussian Blue dye. Optical transmission modulation of ～96% is achieved by electrochemically switching the dye between its oxidized and reduced states using voltages below 1 V. High spatial overlap and long interaction length between the SPP and the active material are achieved by preferential growth of PB nanocrystals on the nanoslit sidewalls. The resulting orthogonalization between the directions of light propagation and that of charge transport from the electrolyte to ultrathin active material inside the nanoslit waveguide offers significant promise for the realization of electrochromic devices with record switching speeds.     

Rethinking adaptation for a 4°C world

With weakening prospects of prompt mitigation, it is increasingly likely that the world will experience 4°C and more of global warming. In such a world, adaptation decisions that have long lead times or that have implications playing out over many decades become more uncertain and complex. Adapting to global warming of 4°C cannot be seen as a mere extrapolation of adaptation to 2°C; it will be a more substantial, continuous and transformative process. However, a variety of psychological, social and institutional barriers to adaptation are exacerbated by uncertainty and long timeframes, with the danger of immobilizing decision-makers. In this paper, we show how complexity and uncertainty can be reduced by a systematic approach to categorizing the interactions between decision lifetime, the type of uncertainty in the relevant drivers of change and the nature of adaptation response options. We synthesize a number of issues previously raised in the literature to link the categories of interactions to a variety of risk-management strategies and tactics. Such application could help to break down some barriers to adaptation and both simplify and better target adaptation decision-making. The approach needs to be tested and adopted rapidly.     

Preservation of high-moisture dried prunes with sodium benzoate instead of potassium sorbate

The relative efficacy of sodium benzoate and potassium sorbate as preservatives for high-moisture dried prunes was determined using prunes with moisture contents between 31 and 38%. As the moisture content of the prunes increased, the level of preservative required increased. Higher concentrations of sodium benzoate than potassium sorbate were required to achieve equal protection of prunes from spoilage. The relative efficacy of these preservatives varies with the type of microbial spoilage. While sodium benzoate generally appeared to be about equally effective against the yeast and moulds used, potassium sorbate was more effective against the mould than against the yeasts. It appeared that it would take 40 to 90% more sodium benzoate than potassium sorbate to preserve high-moisture dried prunes from both types of spoilage. On the basis of the present commercial levels of potassium sorbate, it should be possible to preserve commercially produced high-moisture dried prunes using sodium benzoate without exceeding the U.S. legal limit of 0.1%.     

Embedding reading comprehension training in content-area instruction.

This study evaluated the effectiveness of comprehension training embedded in a program that taught science content to 2nd graders. The program included instruction about the structure of compare-contrast expository text, emphasizing clue words, generic questions, graphic organizers, and the close analysis of well-structured text exemplars. This program was compared with a program that focused on the science content but included no compare-contrast training as well as with a no-instruction control. Regular classroom teachers (14 from 4 schools), randomly assigned to treatment, provided the instruction; 215 students (7-8 years old) participated. The study replicated acquisition and transfer effects found in an earlier study, that is, transfer to compare-contrast text with content related and unrelated to the instructional content (with no loss in the amount of science content acquired). The program also led to better performance on written and oral response measures and on 1 of the 2 measures involving authentic (less well-structured) compare-contrast text. These findings support and extend previous findings that explicit instruction in comprehension is effective as early as the primary-grade level. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A statistical based circumferentially cracked pipe fracture mechanics analysis for design or code implementation

This paper discusses a simple engineering approach to evaluate surface flaws in carbon steel or stainless steel piping and their weldments. It is based on statistical data from a large number of pipe fracture experiments. To ensure a reasonably conservative approach, a 95-percent confidence level was established. Toughness and pipe size effects are accounted for in one correction factor, while ovalization and flow stress effects are accounted for in two other factors. The limitations and possible improvements to such an approach are also discussed.     

Psychopathy in instrumental and reactive violent offenders.

Can violent offenders who commit acts of instrumental aggression for goal-oriented purposes such as robbery be distinguished from those who commit acts of reactive (or hostile) aggression in response to provocation? Because violent offenders often have a history of both instrumental and reactive aggression, this study distinguished between offenders with a history of at least 1 instrumental violent offense and offenders with a history of reactive violent offenses. Two studies tested the hypothesis that instrumental offenders would score higher than reactive offenders and nonviolent offenders on R. D. Hare's (1991) Psychopathy Checklist. The first study sample consisted of 106 violent and nonviolent offenders recruited from a medium-security correctional facility. The second study sample consisted of 50 violent offenders referred for pretrial forensic evaluation. In both samples, instrumental offenders could be reliably distinguished from reactive offenders on the basis of violent crime behavior and level of psychopathy. Group differences could not be attributed to participant age, race, length of incarceration, or extent of prior criminal record. (PsycINFO Database Record (c) 2010 APA, all rights reserved)