Abstract: Sustainable woody biofeedstock production systems require a reliable supply of woody biomass that could be affected by future climate change. However, there is limited understanding of the climatic sensitivity of short rotation woody crops, such as hybrid aspens. The general objective of this study is to identify climatically resilient hybrid aspen clones for woody biomass feedstock development. Specifically, tree-ring analysis methods (dendrochronology) were used to quantify the influence of climate on stem growth rates of hybrid aspens by measuring year-to-year changes in tree-ring width from different cultivars of hybrid aspen and relating annual growth patterns with past instrumental climate records (i.e., temperature and moisture index). Tree-ring analysis was conducted on a full-sib progeny plantation of different cultivars of hybrid aspens (Populus × smithii derived from different geographical variants of aspen parents: trembling aspen (Populus tremuloides) and bigtooth aspen (Populus grandidentata) located on Michigan State University property in the Sandhill Research Area (42.7°N latitude; 84.5°W longitude). Overall, the hybrid aspen families examined in this study were more sensitive to moisture related stressors compared to a weaker or no response to temperature stressors. By the end of the 21st century (2071–2100), 11 out of the 18 hybrid aspen families will be vulnerable to future changes in moisture stress, while the remaining families were screened to be resilient to future changes in moisture stress.
Abstract: A magnitude-frequency analysis of rockslide-debris avalanche deposits was performed. Hummocks are conical mounds formed in debris avalanche deposits from the catastrophic sector collapse of a mountain (often volcanic) that represent relatively cohesive fragments of the mountain edifice. Examination of 17 debris avalanche deposits in Japan and the Philippines showed that, in general, the larger the magnitude of the hummocks, the smaller their frequency. Hummocks followed an exponential distribution: log10N(x) = a – bx, where N(x) is the cumulative number of hummocks with magnitude ≥ x and a and b are constants; x is equal to log10A, where A is the area of a hummock. The constants a and b were positively correlated. The value of b, which differs among avalanches and in this analysis ranged between 1 and 3, may be controlled by the mobility of the debris avalanche. Avalanches with higher mobility (relatively longer runout) have higher b and potentially produce more numerous fragments forming hummocks (i.e., higher a). From the above correlation, the magnitude-frequency relationship can be used to roughly estimate the original height of the collapsed volcanic body, if the runout distance of the rockslide–debris avalanche can be estimated with sufficient accuracy.
Abstract: Air pollution induces the development of black crusts on the surface of built heritage materials. Black layers on the limestone used on an emblematic Madrilenian building dating from the early twentieth century, mainly built up in the 20 years lapsing between two façade cleaning operations, was studied with POM and SEM-EDS. Particulate matter deposited on surfaces in the same period was analyzed with XRD and IC. Climate change in the environs was also studied and façade coloring patterns were compared. Since black crust and settled dust composition, as well as façade soling intensity, were found to be closely related to the surrounding environment, both are proposed as environment and climate change markers. These are considerations, moreover, that must be addressed when designing conservation strategies. Domestic heating systems and vehicle traffic were identified as the two main sources of pollution throughout the period studied in the target area, where the temperature steadily rose and relative humidity declined. The progressive replacement of coal with gas oil in domestic heating boilers and the proliferation of vehicles with diesel engines have mostly determined the evolution of the pollutants emitted. The color of façade soiling, in turn, has been primarily conditioned by the typology of the particles deposited on the limestone surface, declining humidity and the passage of time.
Abstract: Thermodynamic data for platinum group (Os, Ir, Ru, Rh, Pd and Pt) minerals are very limited. The present study is focused on the calculation of the Gibbs free energy of formation (ΔfG°) for selected PGM occurring in layered intrusions and ophiolite complexes worldwide, applying available experimental data on their constituent elements at their standard state (ΔG = G(species) − ΔG(elements)), using the computer program HSC Chemistry software 6.0. The evaluation of the accuracy of the calculation method was made by the calculation of (ΔGf) of rhodium sulfide phases. The calculated values were found to be ingood agreement with those measured in the binary system (Rh + S) as a function of temperature by previous authors (Jacob and Gupta (2014). The calculated Gibbs free energy (ΔfG°) followed the order RuS2 < (Ir,Os)S2 < (Pt, Pd)S < (Pd, Pt)Te2, increasing from compatible to incompatible noble metals and from sulfides to tellurides.