No abstract

Abstract:In many European countries, there are building stocks in need of extensive renovation. This constitutes an important opportunity to perform energy-saving measures and improve indoor environmental quality aiming at a more sustainable built environment. In this paper, we report results from an interview study with the aim of obtaining an in-depth understanding of renovation processes and how sustainability aspects are handled by various Swedish property owners. Examples of important barriers revealed in the interviews are insufficient inspection of existing buildings, absence of both overarching and detailed sustainability targets and guidelines, and lack of knowledge about sustainability aspects. Based on the interview study, conclusions are drawn for the further development of a process model which aims at systematize integration and effectively address energy, environmental, and indoor environmental quality aspects throughout a renovation process; we refer to this as sustainable renovation. Some key starting points for the process model are to suggest routines, provide checklists and tools, and offer guidance for formulating sustainability targets. However, the interviews show that in order to reach a more sustainable built environment, there is a need for government subsidies, other incentives or new business models that value environmental aspects higher.

The influence of the strain state on the thermodynamics of hydrogen in quasi-two-dimensional potentials is reported. The host lattice is V embedded in Fe in the form of a Fe/V(001) superlattice, which represents a strongly confined absorption potential extending over just 13 monolayers. ΔH̄H and ΔS̄H for the continuous solubility region are calculated from the measured isotherms. Two phase transitions are observed for atomic ratios up to c = 1 in the temperature region 50-300 °C. The first transition occurs in the range 0.03⩽c⩽0.07, and shows a Curie-Weiss behaviour. No corresponding phase boundary exists in bulk vanadium hydrides. The second transition, at c≃0.35 and T<150 °C, exhibits large hysteresis and involves an ordering not previously observed in thin vanadium layers. The site blocking at low concentrations scales linearly with the initial strain and yields a blocking concentration of c = 0.083(1) at zero strain, as compared to 0.415(9) in bulk V. This difference is ascribed to the finite-size of the host lattice.

No abstract

The elastic interaction of hydrogen in Nb/W͑110͒ superlattices and the effect of biaxial compressive strain of the Nb layers on the hydrogen lattice-gas to hydrogen lattice-liquid (␣Ϫ␣Ј) phase boundary are explored. The epitaxial growth of Nb on W introduces biaxial compressive strain in the Nb layers and the degree of compression is governed by the thickness ratio of the constituents. Hydrogen solubility isotherms of four samples of increasing W-layer thickness (D W ϭ3 -18 ML) and a constant Nb-layer thickness ͑12 ML͒ were measured by combining resistivity measurements and the 1 H( 15 N,␣␥) 12 C nuclear reaction. ⌬H H and ⌬S H as functions of the hydrogen concentration and W-layer thickness were deduced. The H-H-interaction was found to depend strongly on the initial strain of the Nb host-lattice. The critical temperature for the ␣-␣Ј transition was determined to be 287 K for the sample with least compressed Nb layers (D W ϭ3), while no transition of this kind is verified for the other samples.