Stochastic process model for timber-concrete composite beam deterioration

The aim of this paper is to present a new stochastic process model that will capture the true nature of deterioration of timber-concrete composite beams. Composite elements such as timber-concrete composite sections are designed to take advantage of compatibility of materials under sustained loading. Applied sustained load on timber-concrete composite structures causes gradual increase of deformation and deflection. In particular for timber-concrete composite beams, component materials will deteriorate at different pace over the life-cycle. In order to enable efficient management of structures in terms of required maintenance, repair and/or replacement, it is essential to be able to capture the uncertain nature of the deterioration process. We focus on modeling the deterioration of mid-span deflection of the timber-concrete composite beam over long term under sustained load. As the increasing deflection of the timber-concrete composite beam over time is generally uncertain and non-decreasing, it can best be regarded as a continuous gamma process. Examples of continuous gamma process representation have been included

Gamma process model for timber-concrete composite beam deterioration prediction

This paper presents the application of the advanced probabilistic slope stability model with precipitation effects (APSMP) developed to assess the performance of small homogeneous earthfill embankment dam slopes, when exposed to future seasonal precipitation scenarios. Here, the UKs latest probabilistic climate model known as UKCP09 is applied. To reflect the critical conditions conducive to slope failure, a benchmark has been developed to identify the change, if any, in the risk classification of the slope’s performance level due to precipitation. Thus, enabling the reassessment of the dam’s risk classification, as categorized by the Flood and Water Management Act 2010. Such an approach could therefore be well placed to support and enhance the decision making process, its impact on the public, especially in relation to future climate effects

Role of magnetic and orbital ordering at the metal-insulator transition in NdNiO3

Soft x-ray resonant scattering at the Ni L2,3 edges is used to test models of magnetic and orbital-ordering below the metal-insulator transition in NdNiO3. The large branching ratio of the L3 to L2 intensities of the (1/2,0,1/2) reflection and the observed azimuthal angle and polarization dependence originates from a non collinear magnetic structure. The absence of an orbital signal and the non collinear magnetic structure show that the nickelates are materials for which orbital ordering is absent at the metal-insulator transition.Comment: 10 pages, 4 figures, Physical Review B rapid communication, to be publishe

Selective capture of CO2 over N2 and CH4: B clusters and their size effects

Using density-functional theory (DFT), we investigate the selectivity of adsorption of CO2 over N2 and CH4 on planar-type B clusters, based on our previous finding of strong chemisorption of CO2 on the B10-13 planar and quasiplanar clusters. We consider the prototype B8 and B12 planar-type clusters and perform a comparative study of the adsorption of the three molecules on these clusters. We find that, at room temperature, CO2 can be separated from N2 by selective binding to the B12 cluster and not to the B8 cluster. Selective adsorption of CO2 over CH4 at room temperature is possible for both clusters. Based on our DFT-adsorption data (including also a semi-infinite Boron sheet) and the available literature-adsorption value for N2 on the planar-type B36 cluster, we discuss the selectivity trend of CO2 adsorption over N2 and CH4 with planar-cluster size, showing that it extends over sizes including B10-13 clusters and significantly larger.Comment: 4 figures, 20 page

Bulk synthesis of stoichiometric/meteoritic troilite (FeS) by high-temperature pyrite decomposition and pyrrhotite melting

Stoichiometric troilite (FeS) is a common phase in differentiated and undifferentiated meteorites. It is the endmember of the iron sulfide system. Troilite is important for investigating shock metamorphism in meteorites and studying spectral properties and space weathering of planetary bodies. Thus, obtaining coarse-grained meteoritic troilite in quantities is beneficial for these fields. The previous synthesis of troilite was achieved by pyrite or pyrrhotite heating treatments or chemical syntheses. However, most of these works lacked a visual characterization of the step by step process and the final product, the production of large quantities, and they were not readily advertised to planetary scientists or the meteoritical research community. Here, we illustrate a two-step heat treatment of pyrite to synthesize troilite. Pyrite powder was decomposed to pyrrhotite at 1023-1073 K for 4-6 h in Ar; the run product was then retrieved and reheated for 1 h at 1498-1598 K in N-2 (gas). The minerals were analyzed with a scanning electron microscope, X-ray diffraction (XRD) at room temperature, and in situ high-temperature XRD. The primary observation of synthesis from pyrrhotite to troilite is the shift of a major diffraction peak from similar to 43.2 degrees 2 theta to similar to 43.8 degrees 2 theta. Troilite spectra matched an XRD analysis of natural meteoritic troilite. Slight contamination of Fe was observed during cooling to troilite, and alumina crucibles locally reacted with troilite. The habitus and size of troilite crystals allowed us to store it as large grains rather than powder; 27 g of pyrite yielded 17 g of stochiometric troilite.Peer reviewe