Alumina-based fiber for solid phase microextraction of alcohols from gaseous samples.

On the basis of the affinity of alumina towards hydroxyl functional groups, a solid phase microextraction (SPME) fiber was constructed using alumina powder and poly(vinyl chloride) (PVC). Different compositions were tested and alumina:PVC (97:3) was selected as an optimun composition. A piece of silver wire was used as fiber support. The fiber producing was simple and could be completed in a few minutes. The mechanical durability of the fiber was so good that only a single fiber was used during this study. Ethanol, 1-butanol, 2-butanol, 1-pentanol, 2-pentanol and cyclohexanol were selected as target analytes. Finally, ethanol concentration in the fruit juices and vinegar was measured using SPME-capillary gas chromatography followed by flame ionization detection.     

BOOK REVIEWS

Book reviewed in this article: Cabell's Directory of Publishing Opportunities in Education, Third Edition, David W. E. Cabell The Bones Book And Skeleton Gamebook, Stephen Cumbaa Thinking Connections: Learning to Think and Thinking to Learn, D.N. Perkins, H. Goodrich, S. Tishman, J. M. Owen     

Fe(Cp)2PF6 catalyzed efficient Strecker reactions of ketones and aldehydes under solvent-free conditions

The synthesis of α-aminonitriles of ketones and aldehydes was performed in very short reaction times (20 min) with excellent yields in the presence of 5 mol % of Fe(Cp)₂PF₆ under solvent-free conditions.     

Influence of N+ ion implantation at different temperatures on nanostructural modifications and characteristics of Al alloy surface

Thick (3.0 mm) Al samples (7049 an alloy with 15 elements) were implanted by N⁺ ions of 30 keV energy and fluence of 5 × 10 ¹⁷ N⁺ cm^?2 at different temperatures. The surface modification of the samples was studied using X-ray diffraction (XRD) and atomic force microscope (AFM) analysis. XRD spectra of the samples clearly showed the formation of different phases of AlN. Crystallite sizes (coherently diffracting domains) obtained from AlN diffraction lines showed that at a certain substrate temperature the crystallite size decreases considerably. AFM images showed the formation of grains on Al samples, and it was observed that both grain size and sample surface roughness first decrease and then increase with temperature (i.e. a minimum at a certain temperature is observed). In addition at this temperature, a minimum of intensity is also observed for the intensity of different phases of AlN and the intensity ratio of AlN (200)/AlN (311). This phenomenon is similar to those obtained for thin films and pure metal foils though the sample studied in this work is an Al alloy and the minimum for Al occurred at a value three times larger than that reported for the above cases. Alloy nature of this sample with 14 elements is responsible for the observed results because they may act as defects. Results may also be affected by the residual gases, substrate temperature, dissociation of water in the chamber and the ion energy. Results also showed that the processes of Al nitride and Al oxide formations are competing with each other; decrease of aluminium nitride phases are associated with increase of aluminium oxide phases.     

CR-hypersurfaces of a conformal Kenmotsu manifold satisfying certain shape operator conditions

In this paper, conformal Kenmotsu manifolds are introduced. We consider CR-hypersurfaces of a conformal Kenmotsu manifold whose shape operator is parallel, scalar, recurrent or Lie \( \xi \)-parallel. It is proved that if the Lee vector field of a conformal Kenmotsu manifold is tangent and normal to these type of CR-hypersurfaces then the CR-hypersurfaces are totally geodesic and totally umbilic, respectively. An example of a three-dimensional conformal Kenmotsu manifold is constructed for illustration that is not Kenmotsu.