Steam reforming of ethanol over Ni/support catalysts for generation of hydrogen for fuel cell applications

The paper reports experimental results concerning the influence of the support nature (TiO₂, ZnO, Al₂O₃ and Al₂O₃–Fe₂O₃) of nickel catalysts on their activity, selectivity and coking phenomenon in the steam reforming of ethanol in the range of 570–870 K. The chemical transformations of ethanol occurring on the catalyst support make its chemical nature an important factor affecting the productivity and selectivity of the process. It was found that the most suitable supports in nickel catalysts designed for hydrogen generation in the steam reforming of ethanol are ZnO and TiO₂. Taking into consideration both the efficiency of hydrogen generation and the intensity of carbon deposition, the optimum temperature of the process of the steam reforming of ethanol is below 750 K. An improvement in the selectivity of hydrogen generation and diminishing of the formation of undesirable products may be obtained by promoting nickel catalysts with sodium.     

Metallacarborane Derivatives Effective against Pseudomonas aeruginosa and Yersinia enterocolitica

Pseudomonas aeruginosa is an opportunistic human pathogen that has become a nosocomial health problem worldwide. The pathogen has multiple drug removal and virulence secretion systems, is resistant to many antibiotics, and there is no commercial vaccine against it. Yersinia pestis is a zoonotic pathogen that is on the Select Agents list. The bacterium is the deadliest pathogen known to humans and antibiotic-resistant strains are appearing naturally. There is no commercial vaccine against the pathogen, either. In the current work, novel compounds based on metallacarborane cage were studied on strains of Pseudomonas aeruginosa and a Yersinia pestis substitute, Yersinia enterocolitica. The representative compounds had IC₅₀ values below 10 µM against Y. enterocolitica and values of 20–50 μM against P. aeruginosa. Artificial generation of compound-resistant Y. enterocolitica suggested a common mechanism for drug resistance, the first reported in the literature, and suggested N-linked metallacarboranes as impervious to cellular mechanisms of resistance generation. SEM analysis of the compound-resistant strains showed that the compounds had a predominantly bacteriostatic effect and blocked bacterial cell division in Y. enterocolitica. The compounds could be a starting point towards novel anti-Yersinia drugs and the strategy presented here proposes a mechanism to bypass any future drug resistance in bacteria.     

Tribological characteristics of one-process and two-process cylinder liner honed surfaces under reciprocating sliding conditions

This paper reports an experimental study of the effect of surface texture on cylinder liner wear. This research is important because the conjunction between piston rings and cylinder liner is one of the major sources to frictional losses in internal combustion engines. Experiments were conducted on a reciprocating tester. Specimens were cut from cylinder liners honed or plateau honed made of grey cast iron of hardness 218 HB. The honing operation was performed in order to obtain very similar values of the Sq parameter of one-process and two-process surfaces. In addition, one-process specimens characterised by different Sq parameter values were tested. Counter-specimens were made from chromium-coated steel C45. It was found that wear of two-process surfaces was lower than that of one-process surfaces characterized by the same Sq parameter. Linear wear of specimens was proportional to initial Sq parameter value. The effect of additional oil pockets created by the burnishing technique on cylinder liner wear was negligible.     

On bounded lattices satisfying Elkan’s law

In this short paper we shall prove that every bounded lattice L with the conditions: (c1) 1′ =  0 and (EL): (a · b′)′ =  b +  a′ · b′ for all a, b ∈ L is a Boolean algebra. This is a more general result than that of Renedo et al. (Proceedings NAFIPS’04, 2004), in which it is proved that every orthocomplemented lattice with (EL) is a Boolean algebra.     

Damage localisation in plate-like structures based on PZT sensors

In this paper, signal processing algorithms for damage localisation purposes in plate-like structures were proposed. Algorithms use elastic wave propagation phenomenon for damage detection and localisation. As a result of application to signals registered from the structure, special maps are created that indicate damage location. In this work the algorithms were introduced, described and experimentally implemented. Also one example coming from numerical simulation was included. The proposed methods were successfully tested on aluminium alloy specimen and carbon–epoxy specimen.     

On singular equilibria of index-1 DAEs

Some qualitative properties of singular equilibria arising in semiexplicit index-1 differential-algebraic equations are discussed in this paper. We extend a taxonomy of singularities from index-0 problems to address situations not covered by the singularity induced bifurcation, singular flow, and associated theorems. Although some related phenomena may occur, different behavior can be expected when the assumptions supporting these results are not satisfied, as is illustrated by several examples. Special attention is paid to the effect that the singular nature of the underlying ordinary differential equation and, eventually, of the solution manifold, has on the behavior of the original singular index-1 problem.Supported by a graduate fellowship from Universidad Politécnica de Madrid. The work of this author was done while he was with the Department of Mathematics at North Carolina State University.Research supported in part by NSF Grants DMS-9714811 and DMS-9802259.     

Zeolite-catalyzed synthesis of 4-phenyl-1,3-dioxolanes from styrene oxide

Y, US-Y and ZSM-5 zeolites were used as suitable catalysts for the synthesis of 4-phenyl-1-1,3-dioxolanes from styrene oxide and aliphatic ketones. The results suggest that the diffusion factor as well as acidity influence the 1,3-dioxolane yield. The probable mechanism of the reaction is discussed.     

X-ray Photoelectron Spectroscopy Studies of Metallic Diborides

The binding energies of core electrons in d -type stoichiometric diborides of several transition metals were measured by X-ray photoelectron spectroscopy. Metal core lines in the diborides shifted either to higher or to lower binding energies compared with those appertaining to corresponding elemental states and varied with the metal. The shifts were < 0.6 eV. Carbides, oxides, and oxycarbides of variable stoichiometries were the major impurities detected in the diborides. The binding energy shifts showed a progressive change as the electronegativity difference between the and the metalloid (boron, carbon, nitrogen, oxygen) increased. This indicated that the bond in boro-oxycarbides may be partially ionic.