Development of a quantitative FI-MS technique for the characterization of high- and nonboiling saturated hydrocarbon mixtures

Summary Using a saturated non-boiling hydrocarbon mixture, the influence of two parameters on the results of field ionization mass spectrometry (FI-MS) measurements was studied: (a) the potential difference between the FI emitter and the counterelectrode; (b) the emitter temperature.Variation of the potential difference had only a minor effect on the average molecular mass measured and had no evident effect on the relative ring number distribution in the sample. In contrast, when the emitter temperature was increased, higher average molecular masses were recorded. Moreover, the average molecular masses shifted to higher ring numbers. In order to control the relationship between the described influences during mixture analysis, measuring instructions have been developed that enable the quantitative analysis of unknown saturated samples. However, average molecular mass of the mixture must be known.

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Entwicklung einer quantitativen FI-MS-Methode zur Charakterisierung von gesättigten hoch- und nichtsiedenden Kohlenwasserstoffgemischen

     

Silver nitrate-acetonitrile and iodine-benzene complexes as studied by NMR in thermotropic liquid crystals

Silver nitrate-acetonitrile and π iodine-benzene complexes in thermotropic liquid crystals have been studied by ¹H, ²H, and ¹³C NMR spectroscopy and by optical microscopy. Evidence for at least two silver complexes in each liquid crystal is presented.     

Kreiszylindrische Behälter auf nachgiebiger Unterlage

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HREM studies of the structure and the oxidation process of copper clusters created by inert gas aggregation

Structure and reactivity with oxigen of Cu clusters in the size range of 4.5±2.5 nm created by the inert gas aggregation technique were studied by HREM. The pure Cu clusters investigated under clean conditions show the structures of MTP's with a small lattice dilatation of the (111) plane of 1.25%. For icosahedral and decahedral particles this dilatation corresponds to a splitting of the nearest neighbour distance showing two different values, i.e. dilatation of 2.2% and contraction of 2.8% for the two edges of the deformed tetrahedral subunits, respectively. Oxidation at room temperature and air pressure of 1 bar only begins after a few minutes of exposure to air, after having undergone creation of probably non-stoichiometric intermediate states in the cuprite Cu₂O structure with the bulk values of the bond lengths.     

A Practical Solution to a Cargo Loading Problem at Bethlehem Steel

The optimum assignment of structural steel shapes to rail cars is an important logistical problem in the steel industry. In this paper, we discuss an application at Bethlehem Steel that not only involves weight and dimensional constraints, but also customer unloading constraints. The formulation is a generalized bin packing problem which is solved by modifying and extending the first fit decreasing algorithm. The solution algorithm, SOLID (for Structural Optimal Loading IDentification), has been used extensively for one of Bethlehem's high tonnage customers providing very good practical (implementable) results that achieve the desired goals. Bethlehem has enhanced this approach for use with other customers.     

Phase dynamics of a detuned single-mode laser

We report measurements on the phase dynamics of a detuned single mode laser which has in the past shown correspondence to the complex Lorenz equation. The corresponding ranges of periodic pulsing, of detuned chaos and of windows within the chaotic domain are investigated.Invited paper