The applicability of the catalytic wet-oxidation to CELSS

The wet oxidation catalysis of Au, Pd, Pt, Rh or Ru on a ceramic honeycomb carrier was traced in detail by 16 to 20 repetitive batch tests each. As a result, Pt or Pd on a honeycomb carrier was shown to catalyze complete nitrogen gasification as N2. Though the catalysts which realize both complete nitrogen gasification and complete oxidation could not be found, the Ru+Rh catalyst was found to be most promising. Ru honeycomb catalyzed both nitrification and nitrogen gasification

Surface spin dynamics of antiferromagnetically coupled frustrated triangular films

Results are presented for spin-wave dispersions in geometrically frustrated stacked triangular antiferromagnets with a thin film or semi-infinite geometry having either zero, easy-plane, or easy-axis anisotropy. Surface effects on the equilibrium spin configurations and excitation spectrum are investigated for the case of antiferromagnetically coupled films, serving to extend previous results on ferromagnetically coupled layers [E. Meloche et al., Phys. Rev. B 74, 094424 (2006)]. An operator equation of motion formalism is applied to systems which are quasi-one and quasi-two dimensional in character. In contrast to the case of ferromagnetically coupled films the new results show surface modes that are well separated in frequency from bulk excitations. Magnetic excitations in thin films with an even or an odd number of layers show qualitatively different behavior. These results are relevant for a wide variety of stacked triangular antiferromagnetics materials.Comment: 24 pages, 9 figure

A study of long range order in certain two-dimensional frustrated lattices

We have studied the Heisenberg antiferromagnets on two-dimensional frustrated lattices, triangular and kagome lattices using linear spin-wave theory. A collinear ground state ordering is possible if one of the three bonds in each triangular plaquette of the lattice becomes weaker or frustrated. We study spiral order in the Heisenberg model along with Dzyaloshinskii-Moriya (DM) interaction and in the presence of a magnetic field. The quantum corrections to the ground state energy and sublattice magnetization are calculated analytically in the case of triangular lattice with nearesr-neighbour interaction. The corrections depend on the DM interaction strength and the magnetic field. We find that the DM interaction stabilizes the long-range order, reducing the effect of quantum fluctuations. Similar conclusions are reached for the kagome lattice. We work out the linear spin-wave theory at first with only nearest-neighbour (nn) terms for the kagome lattice. We find that the nn interaction is not sufficient to remove the effects of low energy fluctuations. The flat branch in the excitation spectrum becomes dispersive on addition of furthet neighbour interactions. The ground state energy and the excitation spectrum have been obtained for various cases.Comment: 18 pages, 9 figure

Magnetism and superconductivity in McM_{c}Ta2_{2}S2_{2}C (M = Fe, Co, Ni, and Cu)

Magnetic properties of $M_{c}$Ta$_{2}$S$_{2}$C ($M$ = Fe, Co, Ni, Cu) have been studied using SQUID DC and AC magnetic susceptibility. In these systems magnetic $M^{2+}$ ions are intercalated into van der Waals gaps between adjacent S layers of host superconductor Ta$_{2}$S$_{2}$C. Fe$_{0.33}$Ta$_{2}$S$_{2}$C is a quasi 2D $XY$-like antiferromagnet on the triangular lattice. It undergoes an antiferromagnetic phase transition at $T_{N}$ (= 117 K). The irreversible effect of magnetization occurs below $T_{N}$, reflecting the frustrated nature of the system. The AF phase coexists with two superconducting phases with the transition temperatures $T_{cu} = 8.8$ K and $T_{cl} = 4.6$ K. Co$_{0.33}$Ta$_{2}$S$_{2}$C is a quasi 2D Ising-like antiferromagnet on the triangular lattice. The antiferromagnetic phase below $T_{N} = 18.6$ K coexists with a superconducting phase below $T_{cu} = 9.1$ K. Both Ni$_{0.25}$Ta$_{2}$S$_{2}$C and Cu$_{0.60}$Ta$_{2}$S$_{2}$C are superconductors with $T_{cu}$ ($= 8.7$ K for Ni and 6.4 K for Cu) and $T_{cl}$ (= 4.6 K common to $M_{c}$Ta$_{2}$S$_{2}$C). Very small effective magnetic moments suggest that Ni$^{2+}$ and Cu$^{2+}$ spins are partially delocalized.Comment: 15 pages, 17 figures, and 3 table

Consumer perspectives on product lifetimes: a national study of lifetime satisfaction and purchasing factors

The extension of product lifetimes of consumer goods has the potential to encourage sustainable consumption, reduce carbon emissions and facilitate a transition to a circular economy. However, current understandings of consumer perspectives on product lifetimes are limited. This paper presents the findings of the first national study of consumer satisfaction with product lifetimes across an exhaustive range of consumer durables. The research was undertaken in the United Kingdom where consumer satisfaction and purchasing factors were studied across eighteen product categories. These product categories were devised from academic and market research undertaken at Nottingham Trent University. In total, 2,207 participants completed the survey and the sample profile was similar to the United Kingdom's population with respect to age and gender. The results indicate that consumers appear generally satisfied with the lifetimes of their products and suggest that efforts to extend product lifetimes should focus on developing business and policy options. However, participants also emphasised that longevity, reliability and guarantee length were important factors in their purchasing decisions. Consumer interest in these factors could indicate that lifetime labelling and the promotion of longer guarantees by manufacturers and retailers may offer pathways to reduce energy and material consumption associated with short-lived products, facilitating movement towards a low carbon circular economy