Continuous physical activity recognition for intelligent labour monitoring

Multimedia Tools and Applications - The paper addresses the problem of human activity recognition based on the data from wearable sensors. Human activity recognition depends on a wide context of...     

Structural study of titanium oxide films synthesized by ion beam-assisted deposition

The application of titanium dioxide (TiO(2)) films as surgical implant coatings for antibiotic attachment depends crucially on their available surface area and thus their surface morphology and crystallinity. Here, we report our fabrication of high Wenzel ratio TiO(2) films targeted to increase the film surface area using the ion beam-assisted deposition (IBAD) technique at high-deposition temperatures (approximately 610 degrees C). The modulation of the films' surface morphology was accomplished by varying the chemical identity of the concurrent ion beams bombarded on the films during the e-beam evaporation process. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) were employed to investigate the surface morphology of the as-deposited films. X-ray diffractometry (XRD) revealed that these nanocrystalline films primarily consist of anatase phase TiO(2). Wenzel ratio, the ratio of the actual surface area to the projected area, of IBAD films prepared with argon, oxygen, and nitrogen ion beams was measured to be 1.52, 1.31 and 1.49, respectively. The effect of the differences in chemical reactivity and ion size of these three type ion beams are discussed to explain the present results.     

Water purification from metal ions using carbon nanoparticle-conjugated polymer nanocomposites

The paper deals with a novel method of obtaining nanocarbon-conjugated polymer nanocomposites (NCPC) using nanocarbon colloids (NCC) and polyethylenimine (PEI) for water purification from metal ions. Size of NCC, process of NCPC synthesis, its chemical characteristics, ratio of NCC and PEI in NCPC, speed of coagulation of NCPC, mechanism of interaction of metal ions with NCPC, ability of removing metal ions from water by NCPC against pH have been studied. NCPC has a bonding capacity of 4.0-5.7 mmol/g at pH 6 for most of the divalent metal ions. Percent of sorption of Zn²⁺, Cd²⁺, Cu²⁺, Hg²⁺, Ni²⁺, Cr⁶⁺ ions is higher than 99%. Lifetime of NCPC before coagulation in the treated water is 1 s-1000 min and depends on the ratio of polymeric molecules and carbon nanoparticle concentrations. Results of laboratory tests of the method are described.     

New developments and implementations in the field of hydrocarbon-stock desulfurization

Processes involving the removal of sulfur compounds from gases and liquid petroleum products are analyzed. Economic expediency of the implementation of low-waste methods of demercaptanization of gases, gasoline and kerosene cuts, gas condensates, and light crudes with the polymeric catalyst KSM is substantiated. A complex desulfurization flow plan, which permits maximum extraction of natural sulfur-organic compounds, lowering of the content of total sulfur in the light cuts, and improvement of hydrofinishing conditions of the heavy cuts is proposed. Translated from Khimiya i Tekhnologiya Topliv i Masel, No. 6, pp. 3–8, November–December, 2008.     

Direct Reductive Amination versus Hydrogenation of Intermediates –A Comparison

The direct reductive amination of acetophenone with benzylamine or piperidine was studied in comparison with the hydrogenation of possible intermediates like a corresponding imine or enamine. No common features in terms of productivity and stereocontrol (in the case of chiral catalysts) have been found for both processes. Hence evaluation of efficient, selective and enantioselective catalysts for direct reductive amination appears to be a separate task.     

A Scrutiny on the Reductive Amination of Carbonyl Compounds Catalyzed by Homogeneous Rh(I) Diphosphane Complexes

The reductive amination of a series of aldehydes with secondary amines and H₂ in the presence of a homogeneous Rh-diphosphane catalyst was studied in order to establish a general mechanism of this reaction and to identify conditions for the improvement of the amine/alcohol ratio in the product. Several possible intermediates as constituents of changing equilibria like half-aminals, N,O-acetals and aminals were observed in the reaction mixture by means of ¹H NMR spectroscopy. In individual trials, these compounds could be successfully hydrogenated under the conditions applied for reductive amination (50 bar H₂ pressure, MeOH). Some evidence is accumulated that half-aminals and N,O-acetals might be key intermediates of the reductive amination. Moreover, it was found that the formation of the undesired product alcohol is likely based on the reduction of the starting carbonyl compound. However, due to numerous equilibria consisting of several intermediates, general conclusions are hard to be drawn. Proof will be given that, in several cases, the efficiency of the reductive amination of aliphatic aldehydes can be significantly improved by prehydrogenation of the cationic [Rh(dppb)(COD)]⁺ complex.     

Robust and Selective Metathesis Catalysts for Oleochemical Applications

The screening of known ruthenium alkylidene complexes in the ethenolysis of methyl oleate shows that the Grubbs-type Ru-catalysts bearing two phosphine donor ligands exhibit high selectivity for the formation of terminal olefins. Second-generation ruthenium catalysts promote almost the exclusive formation of self-metathesis products. Complexes with chelating alkylidene moieties (Hoveyda-type) generally exhibit poor selectivity for both ethenolysis and self-metathesis products. Complexes 2b and 2d promote self-metathesis of methyl oleate with catalyst loading of 2?ppm without significant isomerization up to 110?°C (using 2d) and up to 150?°C (using 2b).     

Oxidative Cleavage of Long Chain Olefins to Carboxylic Acids with Hydrogen Peroxide

The role of phase-transfer catalysts (PTC) (ammonium and phosphonium salts) with various anions on the biphasic oxidative cleavage of long chain olefins with aqueous hydrogen peroxide catalyzed by Na₂WO₄/H₃PO₄/PTC system has been investigated. It was shown that the nature of PTC widely affects the catalytic activity of the above system in the conversion of alkenes, cycloalkenes and unsaturated fatty acids into carboxylic acids.