Comments on the use of buckminsterfullerene encapsulated in zeolite Y as a potential catalyst

Buckminsterfullerene encapsulated within zeolite Y is found not to be a reactive radical initiator for the formation of dimethoxyethane from dimethyl ether below 200° C. Above this temperature the expected acid catalysed conversion of dimethyl ether to hydrocarbons is observed. Dimethoxyethane formation is observed when bibenzoyl peroxide is used as a radical initiator. These studies indicate that any radical formed by the encapsulated buckminsterfullerene is relatively unreactive.     

Azide Reactive Dyes

Reactive dyes containing a sulphonylazide group can undergo fixation on nylon substrates by two different mechanisms. Under aqueous dyeing conditions, at or below 120d? C, the free amino end-groups of the polymer attack the sulphonylazide group with displacement of azide ion, and results in attachment of the dye to the substrate by a sulphonamide linkage. In contrast, if the dyed substrate is subjected to dry heat fixation at 170d? C, the azide group decomposes to a sulphonylnitrene species which undergoes insertion into C-H bonds of the polymer. The dye is again attached by a sulphonamide bridge, but in this case the amount of dye that can be fixed is independent of the amino end-group content of the polymer.     

The Effect of Organic Diluent on the Extraction of Eu(III) by HEH[EHP]

ABSTRACT

Because there are fewer tools available to probe the interactions therein, the effect of the fundamental chemistry of the organic diluent on solvent extraction equilibria has been under-characterized relative to the aqueous. As a result, diluents for solvent extraction are often selected for an application not for their utility as a medium for reaction, but for other (often equally) important reasons (like low flammability). To begin to improve this imbalance in the science, twenty different diluents have been used in a study of the extraction of radiotracer ^152/154Eu³⁺ from dilute nitric acid solutions using the extractant 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (HEH[EHP]). To increase the utility of the study and to honor the memory of Professor Jan Rydberg, this investigation was conducted by a cadre of comparatively inexperienced separation scientists (who are as a result no longer inexperienced separation scientists) as a radioanalytical chemistry and solvent extraction educational exercise. Slope analysis was used to determine the apparent stoichiometry of the extracted metal complex. The results discussed in the following indicate that, while the pH dependence exhibits the expected three H⁺ exchanged per metal ion extracted, the extractant dependence suggests that the number of protonated extractant molecules in the extracted complex changes with the organic diluent. The experimentally observed “extractant dependency” ranges from 2.5 to 3.0 dimer equivalent molecules per extracted metal ion. Ironically, in the diluents exhibiting the highest apparent M:(HA)₃ stoichiometry, HEH[EHP] extracts Eu³⁺ less efficiently. Europium luminescence spectroscopy was used to probe for changes in the first coordination sphere of the complex in different diluents. A model and conceptual framework for understanding these observations is described.     

TEM Characterization of Single- and Multilayer Triol-Based Sol–Gel PZT (53/47) Thin Films

Integrated lead zirconate titanate thin films deposited on Pt/Ti/SiO₂/Si substrates using a novel triol-based route were characterized using X-ray diffraction and transmission electron microscopy. Crack-free single-layer PZT films of up to 200 nm thick were prepared by triol-based sol–gel processing onto Pt/Ti/SiO₂/Si substrates. Films ∼75 nm thick exhibited a microstructure free of pores and second phase. As film thickness increased, film texture changed from {100} to {111} perovskite. Essentially, single-phase multilayer films could be prepared by the deposition and pyrolysis of several 75 nm layers, followed by a single crystallization step. The influence of heat-treatment schedule on the microstructure and orientation of the multilayer films is discussed. Comparison has been made between multilayer films prepared using the triol-based sol and an inverted mixing order/acetic acid-based sol.     

Temperature and processing effects on lithium ion conductivity of solution-deposited lithium zirconium phosphate (LiZr2P3O12) thin films

Lithium zirconium phosphate (LiZr₂P₃O₁₂) thin films have been prepared on platinized silicon substrates via a chemical solution deposition approach with processing temperatures between 700°C and 775°C. Films that were subject to a single high-temperature anneal were found to crystallize at temperatures above 725°C. Crystallization was observed in films annealed after each deposited layer at 700°C and above. In both cases, grain size was found to increase with annealing temperature. Ion conductivity was found to increase with annealing temperature in singly annealed films. In per-layer annealed films ion conductivity was found to initially increase then decrease with increasing annealing temperature. A maximum ion conductivity of 1.6 × 10⁻⁶ S/cm was observed for the singly annealed 775°C condition, while a maximum ion conductivity of 5.8 × 10⁻⁷ S/cm was observed for the 725°C per-layer annealed condition. These results are consistent with an increasing influence of cross-plane, internal interface resistance and vapor phase carrier loss in the per-layer annealed samples. This work demonstrates that post-deposition processing methods can strongly affect the ion conducting properties of LiZr₂P₃O₁₂ thin films.     

Biobased flexible polyurethane foams manufactured from lactide-based polyester-ether polyols for automotive applications

In this study, biobased polyester-ether polyols derived from meso-lactide and dimer acids were evaluated for flexible polyurethane foams (PUF) applications. Initially, the catalyst concentration was optimized for the biobased PUF containing 30% of biobased polyol (70% petroleum-based polyol). Then, the same formulation was used for biobased PUF synthesis containing 10%–40% of biobased polyols. The performance of biobased PUF was compared with the performance of the control foam made with 100% petroleum-based polyol. The characteristic times (cream, top of the cup, string gel, rise, tack-free) of biobased PUF were determined. The biobased PUF were evaluated for the mechanical (tensile and compressive) and morphological properties. As the wet compression set is important for automotive applications, it was measured for all biobased PUF. The thermal degradation behavior of biobased PUF was also evaluated and compared with the control foam. The effect of different hydroxyl and acid values of polyols on the mechanical properties of biobased PUF is also discussed. The miscibility of all components of PUF formulations is crucial in order to produce a foam with uniform properties. Thus, the miscibility of biobased polyols with commercial petroleum-based polyol was studied.     

Subroutine based detection of APT malware

Statistical detection of mass malware has been shown to be highly successful. However, this type of malware is less interesting to cyber security officers of larger organizations, who are more concerned with detecting malware indicative of a targeted attack. Here we investigate the potential of statistically based approaches to detect such malware using a malware family associated with a large number of targeted network intrusions. Our approach is complementary to the bulk of statistical based malware classifiers, which are typically based on measures of overall similarity between executable files. One problem with this approach is that a malicious executable that shares some, but limited, functionality with known malware is likely to be misclassified as benign. Here a new approach to malware classification is introduced that classifies programs based on their similarity with known malware subroutines. It is illustrated that malware and benign programs can share a substantial amount of code, implying that classification should be based on malicious subroutines that occur infrequently, or not at all in benign programs. Various approaches to accomplishing this task are investigated, and a particularly simple approach appears the most effective. This approach simply computes the fraction of subroutines of a program that are similar to malware subroutines whose likes have not been found in a larger benign set. If this fraction exceeds around 1.5 %, the corresponding program can be classified as malicious at a 1 in 1000 false alarm rate. It is further shown that combining a local and overall similarity based approach can lead to considerably better prediction due to the relatively low correlation of their predictions.     

A versatile facility for laboratory studies of viscoelastic and poroelastic behaviour of rocks

Novel laboratory equipment has been modified to allow both torsional and flexural oscillation measurements at sub-microstrain amplitudes, thereby providing seismic-frequency constraints on both the shear and compressional wave properties of cylindrical rock specimens within the linear regime. The new flexural mode capability has been tested on experimental assemblies containing fused silica control specimens. Close consistency between the experimental data and the results of numerical modelling with both finite-difference and finite-element methods demonstrates the viability of the new technique. The capability to perform such measurements under conditions of independently controlled confining and pore-fluid pressure, with emerging strategies for distinguishing between local (squirt) and global (specimen-wide) fluid flow, will have particular application to the study of frequency-dependent seismic properties expected of cracked and fluid-saturated rocks of the Earth's upper crust.