Direct alcohol fuel cells: A novel non-platinum and alcohol inert ORR electrocatalyst

In the present investigation, a series of binary Pd_xFe_y/C electrocatalysts for the oxygen reduction reaction (ORR) was synthesized in a very short time by employing a pulse-microwave assisted polyol method. The physico-chemical properties were obtained by employing the techniques of X-ray diffraction (XRD) and transmission electron microscopy (TEM). The electrochemical activity was studied by the aid of the techniques of cyclic voltammetry and rotating disk electrode. Based on the obtained experimental results, it can be deduced that the addition of Fe increases the activity of Pd towards the reaction of oxygen reduction. More precisely, when the molar ratio between Pd and Fe was 3:1, the highest oxygen reduction activity among all the investigated Pd_xFe_y/C catalysts was obtained. It was also found that Pd₃Fe₁/C exhibited an oxygen reduction activity comparable to that of Pt/C, while showed almost no activity for alcohols oxidation. Moreover, in the simultaneous presence of both methanol and oxygen, Pd₃Fe₁/C displayed an excellent selectivity for oxygen reduction reaction.     

Robust output feedback control of quasi-linear parabolic PDE systems

This paper proposes a methodology for the synthesis of nonlinear robust output feedback controllers for systems of quasi-linear parabolic partial differential equations with time-varying uncertain variables. The method is successfully applied to a typical diffusion–reaction process with uncertainty.     

Silver Nanoparticles and Graphitic Carbon Through Thermal Decomposition of a Silver/Acetylenedicarboxylic Salt

Spherically shaped silver nanoparticles embedded in a carbon matrix were synthesized by thermal decomposition of a Ag(I)/acetylenedicarboxylic acid salt. The silver nanoparticles, which are formed either by pyrolysis at 300 °C in an autoclave or thermolysis in xylene suspension at reflux temperature, are acting catalytically for the formation of graphite layers. Both reactions proceed through in situ reduction of the silver cations and polymerization of the central acetylene triple bonds and the exact temperature of the reaction can be monitored through DTA analysis. Interestingly, the thermal decomposition of this silver salt in xylene partly leads to a minor fraction of quasicrystalline silver, as established by HR-TEM analysis. The graphitic layers covering the silver nanoparticles are clearly seen in HR-TEM images and, furthermore, established by the presence of sp² carbon at the Raman spectrum of both samples.     

Performance evaluation of supercomputers using HPCC and IMB Benchmarks

The HPC Challenge (HPCC) Benchmark suite and the Intel MPI Benchmark (IMB) are used to compare and evaluate the combined performance of processor, memory subsystem and interconnect fabric of five leading supercomputers—SGI Altix BX2, Cray X1, Cray Opteron Cluster, Dell Xeon Cluster, and NEC SX-8. These five systems use five different networks (SGI NUMALINK4, Cray network, Myrinet, InfiniBand, and NEC IXS). The complete set of HPCC Benchmarks are run on each of these systems. Additionally, we present Intel MPI Benchmarks results to study the performance of 11 MPI communication functions on these systems.     

Initial use of 1-hydroxybenzotriazole in the chemistry of group 12 metals: An 1D zinc(II) coordination polymer and a mononuclear cadmium(II) complex containing the deprotonated ligand in a novel monodentate ligation mode

The chemistry of 1-hydroxybenzotriazole (btaOH) with the group 12 metal ions Zn(II) and Cd(II) resulted in the 1D coordination polymer [Zn(btaO)₂]_n (1) and the mononuclear complex [Cd(btaO)₂(H₂O)₄] · 3H₂O (2 · 3H₂O), respectively. Polymer 1 forms double-stranded chains which are further supported by weak C–H?O hydrogen bonds resulting in a pcu (primitive cubic) rod packing. The mononuclear complexes of 2 form undulating hydrogen bonded layers while the lattice water molecules form 1D hydrogen bonded tapes, comprising 4- and 6-membered rings, within the layers and bridge them to the third dimension. The thermal and optical properties of both compounds are presented. IR data are discussed in terms of the chemical composition of the compounds and the coordination mode of btaO^?.     

Classification and calculation of primary failure modes in bread production line

In this study, we describe the classification methodology over a 2-year period of the primary failure modes in categories based on failure data of bread production line. We estimate the probabilities of these categories applying the chi-square goodness of fit test, and we calculate their joint probabilities of mass function at workstation and line level. Then, we present numerical examples in order to predict the causes and frequencies of breakdowns for workstations and for the entire bread production line that will occur in the future. The methodology is meant to guide bread and bakery product manufacturers, improving the operation of the production lines. It can also be a useful tool to maintenance engineers, who wish to analyze and improve the reliability and efficiency of the manufacturing systems.     

Evaluation of thermally-dried Kluyveromyces marxianus as baker’s yeast

The aim of the present study was to evaluate the use of thermally-dried Kluyveromyces marxianus as baker’s yeast. Bread samples produced by thermally-dried K. marxianus were compared with samples produced by wet K. marxianus culture and by commercial baker’s yeast. The type of the culture had no effect on loaf weight, loaf volume, specific loaf volume, density or moisture loss, in contrast to pH, total titrable acidity (TTA), and moisture content. The use of thermally-dried K. marxianus resulted in lower pH values and higher TTA, while the bread samples showed higher resistance to spoilage as counts of moulds and yeasts were significantly lower during preservation. The SPME GC/MS analysis of volatiles and the preliminary sensory evaluation showed no significant differences in the profile of aroma-related compounds or overall quality of the tested samples.     

Stereodifferentiation of geosmin in wine

Geosmin (trans-1,10-dimethyl-trans-9-decalol), a well-known, highly odorous compound, has recently been identified and quantified in red and sweet white wines, as well as in grape juice before alcoholic fermentation. Geosmin is a chiral compound and the (-) form is much more odoriferous than the (+) form. Enantioselective multidimensional gas chromatography analysis of a purified Cabernet Sauvignon wine extract revealed the presence of only one enantiomer: (-) geosmin. In grape juices obtained from rotten grapes and in wines this compound can be found at concentrations much higher than its olfactory perception threshold, indicating that it contributes to their earthy aroma. (-) Geosmin is also the only enantiomer to have been identified in pure cultures of Streptomyces sp. and Penicillium sp. strains isolated from rotten grapes.