Al-Mn-Ce quasicrystalline composites: Phase formation and mechanical properties

Aluminium-based composites with quasicrystalline particles as reinforcements were synthesized via the powder metallurgy processing route. In order to obtain bulk samples with a nanoscale microstructure most equivalent to that resulting from rapid solidification, powders of Al-Mn-Ce alloys were prepared by pulverization of melt-spun ribbons using a planetary ball mill. Significant differences in the phase formation upon quenching, composite microstructure and thermal stability of the microstructure were found for different alloy compositions. Severe grain growth during the subsequent consolidation by hot extrusion caused the formation of a micrometre-scale composite instead of the nanoscale phase mixture initially existing after rapid solidification. After hot extrusion, the specimens were deformed by compression at a constant compression rate at room temperature. With an ultimate strength of up to 975 MPa and a ductility of more than 4% the material yields excellent properties compared with conventionally produced aluminium-based alloys.     

A simple proof of the Rogers–Selberg identities

A short and simple proof of the Rogers–Selberg identities is obtained from the work of Andrew Sills on identities of the Rogers–Ramanujan type.     

Magnetomechanical training of single crystalline Ni-Mn-Ga alloy

A 5M Ni-Mn-Ga single crystal was investigated, supplied by Adaptamat Ltd, Finland. Especially low temperature magnetic actuation as well as cyclic tensile-compression tests revealed promising properties, which provide useful insights for training concepts in polycrystalline materials. Successive compressions lead to a significant reduction of the twinning stress by a factor of two.     

Characterization of Coal Tar Pitch Oils by Nuclear Magnetic Resonance

Nuclear Magnetic Resonance (NMR) spectrometry has been used to characterize coal tar pitch oils, which had been obtained from a low-temperature carbonization of high volatile bituminous coal. NMR provides data on hydrogen distribution in coal oils and structural correlations established on elution chromatographic, on distillation fractions, and on the residues remaining after distillation. This research is the first report on the hydrogen distribution of coal tar pitch oils by NMR.     

The definition of the toxicologically relevant applicability domain for the SNAr reaction for substituted pyridines and pyrimidines

This study outlines how results from a glutathione reactivity assay (so-called in chemico data) can be used to define the applicability domain for the nucleophilic aromatic substitution (S_NAr) reaction for nitrogen-containing aromatic compounds. S_NAr is one of the six mechanistic domains that have been shown to be important in toxicological endpoints in which the ability to bind covalently to a protein is a key molecular initiating event. This study has analysed experimental data (2 h RC₅₀ values), allowing a clear and interpretable structure–activity relationship to be developed for pyridines and pyrimidines which reside within the S_NAr domain. The in-ring nitrogen(s) act as activating groups in the S_NAr reaction. The position(s) of the in-ring nitrogen(s) as well as other activating groups, especially in relationship to the leaving group, affect reactive potency. The experimentally defined applicability domain has resulted in a series of structural alerts. These results build on early work on the benzene derivatives residing in the S_NAr domain. The definition of the applicability domain for the S_NAr reaction and the resulting structural alerts are likely to be beneficial in the development of computational tools for category formation and read-across in hazard identification, and the development of adverse outcome pathways.