A numerical study of a method for measuring the effective in situ sound absorption coefficient

The accuracy of a method [Wijnant et al., “Development and applica- tion of a new method for the in-situ measurement of sound absorption”, ISMA 31, Leuven, Belgium (2010).], for measurement of the effective area-averaged in situ sound absorption coefficient is investigated. Based on a local plane wave assump- tion, this method can be applied to sound fields for which a model is not available. Investigations were carried out by means of finite element simulations for a typical case. The results show that the method is a promising method for determining the effective area-averaged in situ sound absorption coefficient in complex sound fields

Exploring the Implications of Monetary Policy Normalisation for Irish Mortgage Arrears. Quarterly Economic Commentary Special Article, Spring 2019.

The current level of the monetary policy rate in the Eurozone is low both by international and historical standards and will likely rise over the coming years. In this Article we consider what the impact of a rise in ECB policy rates would mean for the Irish mortgage market. First, we examine the structure of the Irish mortgage market in terms of interest rate contract types and explore the link between the mortgage rate and the policy rate. Second, we draw out the results of policy modelling linking arrears and interest rates using a model put forward in Slaymaker et al. (2019). We then use this model to provide some further scenarios exploring the impact of interest rate rises on the arrears rate for particular groups of Irish households. Our findings suggest a 25 basis point increase in the policy rate would lead to a 0.1 percentage point increase in new missed mortgage payments. While households are in a better economic position to withstand policy rate increases given the recovery in the labour market and in house prices, rate rises would lead to payments rising faster than long-term income growth. Younger, lower income households who are at an earlier stage in their mortgage contract are more at risk, as are households on tracker interest rates who have a contractual pass-through from the policy rate to the lending rate

Variational quantum Monte Carlo calculations for solid surfaces

Quantum Monte Carlo methods have proven to predict atomic and bulk properties of light and non-light elements with high accuracy. Here we report on the first variational quantum Monte Carlo (VMC) calculations for solid surfaces. Taking the boundary condition for the simulation from a finite layer geometry, the Hamiltonian, including a nonlocal pseudopotential, is cast in a layer resolved form and evaluated with a two-dimensional Ewald summation technique. The exact cancellation of all Jellium contributions to the Hamiltonian is ensured. The many-body trial wave function consists of a Slater determinant with parameterized localized orbitals and a Jastrow factor with a common two-body term plus a new confinement term representing further variational freedom to take into account the existence of the surface. We present results for the ideal (110) surface of Galliumarsenide for different system sizes. With the optimized trial wave function, we determine some properties related to a solid surface to illustrate that VMC techniques provide standard results under full inclusion of many-body effects at solid surfaces.Comment: 9 pages with 2 figures (eps) included, Latex 2.09, uses REVTEX style, submitted to Phys. Rev.