New Approaches to Coupling TLC with TOF-SIMS

JPC – Journal of Planar Chromatography – Modern TLC - A new hyphenated technique that enables coupling of thin-layer chromatography (TLC) with time-of-flight secondary-ion mass...     

An acceleration of Erlenkotter-Körkel’s algorithms for the uncapacitated facility location problem

This contribution is focused on an acceleration of branch and bound algorithms for the uncapacitated facility location problem. Our approach is based on the well-known Erlenkotters’ procedures and Körkels’ multi-ascent and multi-adjustment algorithms, which have proved to be the efficient tools for solving the large-sized instances of the uncapacitated facility location problem. These two original approaches were examined and a thorough analysis of their performance revealed how each particular procedure contributes to the computational time of the whole algorithms. These analyses helped us to focus our effort on the most frequent procedures. The unique contribution of this paper is a new dual ascent procedure. This procedure leads to considerable acceleration of the lower bound computation process and reduces the resulting computational time. To demonstrate more efficient performance of amended algorithms we present the results of extensive numerical experiments.     

Photoinduzierte umlagerung von isoxazolinen: Syntheseweg zu 2,4,5,8-Tetrahedron-1,3-dicx-5-azocinen

A high yield 2,4,5,8-tetrahydro-1,3-diox-5-azocine synthesis, which employs a sequence of cycloaddition and photoinduced rearrangement has been developed.     

Classification of wine distillates using multivariate statistical methods based on their direct GC-MS analysis

This work describes a novel methodology for the recognition of brandies based on direct injection of a raw sample followed by GC-MS analysis. Direct injection was chosen for its simplicity and the fact that the composition of the samples analysed remains unchanged compared to original brandy. The repeatability of the analytical procedure was evaluated by a comparison of the peak areas for randomly selected compounds obtained from 10 parallel measurements. A novel chemometric procedure was investigated in order to separate the samples studied on the basis of their geographical origin, processing technology or maturation time. In this procedure, a principal component analysis was applied to full chromatograms to select the time interval that shows the significant differences between the samples studied. It was shown that the chromatogram recorded at 36–39 min bore the maximal differences, hence it could be used to classify the brandy samples. The chromatographic peaks found within this time interval were identified and their peak areas determined. These compounds could be used as specific markers for determining geographical origin or processing technology.     

Topological Properties of the Space of Convex Minimal Usco Maps

Set-Valued and Variational Analysis - We investigate the space of convex minimal usco maps from a Tychonoff space to the space of real numbers. Its elements are set-valued maps that are important...     

Quasicontinuous Subcontinuous Functions and Compactness

Mediterranean Journal of Mathematics - Let X be a locally compact space and (Y, d) be a metric space. A subfamily $${\mathcal E}$$ of the space of quasicontinuous subcontinuous functions from X to...