Openness, imported commodities and the Phillips Curve

This paper derives a Phillips curve with imported commodities as an additional input in the production process. Given greater reliance on exogenously priced imported commodities in production then changes in output lead to a reduced impact on marginal costs and prices. The Phillips curve becomes flatter relative to the bench-mark New Keynesian case. Empirical evidence supports the hypothesis that greater imported commodity intensity in production increases the sacrifice ratio. Econometrically controlling for imported commodity intensity also doubles the explanatory power of openness in determining the sacrifice ratio, as conjectured by Romer (1993).openness, imported commodities, sacrifice ratio

Synthesis and methane cracking activity of a silicon nitride supported vanadium nitride nanoparticle composite

The co-ammonolysis of V(NMe2)4 and Si(NHMe)4 with ammonia in THF and in the presence of ammonium triflate ([NH4][CF3SO3]) leads to the formation of monolithic gels. Pyrolysing these gels produces mesoporous composite materials containing nanocrystalline VN and amorphous silicon imidonitride. Elemental mapping indicated a thorough distribution of VN with no evidence of large cluster segregation. Whilst not active for ammonia synthesis, the silicon nitride based materials were found to possess activity for the COx-free production of H2 from methane, which makes them candidates for applications in which the presence of low levels of CO in H2 feedstreams is detrimental

Self-propagating metathesis preparations of inorganic materials.

The potential of self-propagating reactions, with reagents such as lithium nitride, calcium nitride, sodium arsenide and magnesium silicide, in the production of inorganic materials has been investigated. Reactions were performed with anhydrous d-block and rare earth metal chlorides and can be described by the following generic equation where M is a Group 3-12 metal, Alk is a Group 1 or 2 element and E is Si, N, P, As, Sb, Bi or O. MClm + xAlknE → yMαE + xAlkClβ + zEγ Crude products were obtained normally as fused masses of material consisting of the products coated in the alkali chloride co-products. Grinding followed by washing with an appropriate solvent yielded the pure products with low levels of contamination from the other elements present in the reaction flux. The phases produced include rare earth and transition metal nitrides, metals and alloys, d-block phosphides, arsenides and antimonides, metal silicides and d-block oxides. The products were variously characterised by X-ray powder diffraction, scanning electron microscopy, energy dispersive X-ray analysis, magnetic susceptability, X-ray photoelectron spectroscopy, microanalysisand solid state (magic angle spinning) nuclear magnetic resonance spectroscopy. Thermocouple experiments, differential scanning calorimetry, photography and constant pressure calculations were used to examine the thermal aspects and timescales of reactions. Dilution with inert solids was used to reduce voracity of reactions and to control crystallinity of products. Liquid chlorides (TiCl4 and VCl4) were successfully employed to make high quality ternary phases such as Ti0.5V0.5E (E= N, P, As). Such reactions can progress via ionic or elemental mechanisms and evidence for either of these was gathered. Examples were found for both mechanisms which supported that the process was occurring. These conclusions were based on end- product analysis since the reaction conditions and timescales precluded the use of other techniques

Redox supercapacitor performance of nanocrystalline molybdenum nitrides obtained by ammonolysis of chloride- and amide-derived precursors

Reactions of MoCl5 or Mo(NMe2)4 with ammonia result in cubic ?-Mo2N or hexagonal ?1-MoN depending on reaction time and temperature. At moderate temperatures the cubic product from Mo(NMe2)4 exhibits lattice distortions. Fairly high surface areas are observed in the porous particles of the chloride-derived materials and high capacitances of up to 275 F g?1 are observed when electrodes made from them are cycled in aqueous H2SO4 or K2SO4 electrolytes. The cyclic voltammograms suggest charge is largely stored in the electrochemical double layer at the surface of these materials. Amide-derived molybdenum nitrides have relatively low surface areas and smaller capacitances, but do exhibit strong redox features in their cyclic voltammograms, suggesting that redox capacitance is responsible for a significant proportion of the charge stored

Nitrogen-rich transition metal nitrides

The solid state chemistry leading to the synthesis and characterization of metal nitrides with N:M ratios >1 is summarized. Studies of these compounds represent an emerging area of research. Most transition metal nitrides have much lower nitrogen contents, and they often form with non- or sub-stoichiometric compositions. These materials are typically metallic with often superconducting properties, and they provide highly refractory, high hardness materials with many technological applications. The higher metal nitrides should achieve formal oxidation states (OS) attaining those found among corresponding oxides, and they are expected to have useful semiconducting properties. Only a very few examples of such high OS nitrogen-rich compounds are known at present. The main group elements typically form covalently bonded nitride ceramics such as Si3N4, Ge3N4 and Sn3N4, and the early transition metals Zr and Hf produce Zr3N4 and Hf3N4. However, the only main example of a highly nitrided transition metal compound known to date is Ta3N5 that has a formal oxidation state +5 and is a semiconductor with visible light absorption leading to applications as a pigment and in photocatalysis. New synthesis routes are being explored to study the possible formation of other N-rich materials that are predicted to exist by ab initio calculations. There is a useful interplay between theoretical predictions and experimental synthesis studies at ambient and high pressure conditions, as we explore and establish the existence and structure–property relations of these new nitride compounds and polymorphs. Here we review the state of current investigations and indicate possible new directions for further work

Performance of nanocrystalline Ni3N as a negative electrode for sodium-ion batteries

Nickel nitride is synthesised by high temperature ammonolysis of nickel(II) hexamine and tris(ethylenediamine) salts. Its electrochemical characteristics are examined in half-cells vs. lithium and sodium. Samples with high surface area are found to have significant reversible charge storage capacity in sodium cells and hence to be a promising negative electrode material for sodium-ion batteries

Localized states in the conserved Swift-Hohenberg equation with cubic nonlinearity

The conserved Swift-Hohenberg equation with cubic nonlinearity provides the simplest microscopic description of the thermodynamic transition from a fluid state to a crystalline state. The resulting phase field crystal model describes a variety of spatially localized structures, in addition to different spatially extended periodic structures. The location of these structures in the temperature versus mean order parameter plane is determined using a combination of numerical continuation in one dimension and direct numerical simulation in two and three dimensions. Localized states are found in the region of thermodynamic coexistence between the homogeneous and structured phases, and may lie outside of the binodal for these states. The results are related to the phenomenon of slanted snaking but take the form of standard homoclinic snaking when the mean order parameter is plotted as a function of the chemical potential, and are expected to carry over to related models with a conserved order parameter.Comment: 40 pages, 13 figure

Matched-filter study and energy budget suggest no detectable gravitational-wave 'extended emission' from GW170817

Van Putten & Della Valle (2018) have reported a possible detection of gravitational-wave 'extended emission' from a neutron star remnant of GW170817. Starting from the time-frequency evolution and total emitted energy of their reported candidate, we show that such an emission is not compatible with the current understanding of neutron stars. We explore the additional required physical assumptions to make a full waveform model, for example, taking the optimistic emission from a spining-down neutron star with fixed quadrupolar deformation, and study whether even an ideal single-template matched-filter analysis could detect an ideal, fully phase-coherent signal. We find that even in the most optimistic case an increase in energy and extreme parameters would be required for a confident detection with LIGO sensitivity as of 2018-08-17. The argument also holds for other waveform models following a similar time-frequency track and overall energy budget. Single-template matched filtering on the LIGO data around GW170817, and on data with added simulated signals, verifies the expected sensitivity scaling and the overall statistical expectation.Comment: 9 pages, 6 figures, updated version as accepted by MNRA