Mixed-species stands are hypothesized to be more structurally diverse because of inherent differences in growth rates between tree species. We investigated three combinations of even-aged, single- and mixed-species coniferous stands in western Canada: (i) shade-tolerant western hemlock (Tsuga heterophylla (Raf.) Sarg.) and western redcedar (Thuja plicata (Donn ex D. Don) Spach), (ii) shade-intolerant lodgepole pine (Pinus contorta Dougl. ex Loud.) and western larch (Larix occidentalis Nutt.), and (iii) shade-intolerant lodgepole pine and shade-tolerant black spruce (Picea mariana (Mill.) BSP). We quantified stand structural diversity based on tree diameter and height by using Shannon's index and the coefficient of variation. Regression analysis was applied to examine the relationships between structural diversity, species composition, and stand age. Mixed-species stands of western hemlock and western redcedar had similar structural diversity to their respective single-species stands. Pine–larch and pine–spruce mixed-species stands had higher tree-size diversity than their respective single-species stands. Stand age was a significant factor for tree-size diversity, but its effect changed in different ways depending on the type of mixtures and index used to measure diversity.

Stand volumes were determined for naturally established, even-aged, single- and mixed-species stands involving three combinations of shade-tolerant and shade-intolerant conifers on similar sites: (i) western redcedar – western hemlock (Thuja plicata Donn ex D. Don – Tsuga heterophylla (Raf.) Sarg.), (ii) lodgepole pine – western larch (Pinus contorta Dougl. ex Loud. – Larix occidentalis Nutt.), and (iii) lodgepole pine – black spruce (Pinus contorta – Picea mariana (Mill.) BSP). Stand volume was significantly increased with site index and breast-height age in all three studies. Stand volume was also related to relative stand density in the lodgepole pine – black spruce study. When both species were shade tolerant (hemlock–redcedar), stand volume increased linearly with the proportion of hemlock; the mixed-species stands had intermediate volume compared with single-species stands. The combination of two shade-intolerant species (pine–larch) had lower stand volume than that anticipated from single-species stands, implying that one species may inhibiting the growth of the other. Mixtures of shade-intolerant and shade-tolerant species with different growth patterns (spruce–pine) may be more productive than single-species stands in specific ecological contexts and developmental stages. The effect of one species on the productivity of another species is tree-species and site specific: at maturity, even-aged, mixed-species coniferous stands are not necessarily more productive than single-species stands.

In this work, Cu based sulfides (chalcopyrite CuFeS 2, mohite Cu 2 SnS 3, tetrahedrite Cu 12 Sb 4 S 13 , mawsonite Cu 6 Fe 2 SnS 8 and kesterite Cu 2 ZnSnS 4 ) were synthesized by industrial milling in an excentric vibration mill to demonstrate scalability of their synthesis. For comparison, laboratory scale milling in a planetary mill was performed. The properties of the obtained samples were characterized by X-ray diffraction, and in some cases, also by Mössbauer spectroscopy. For densification of powders the method of Spark Plasma Sintering was applied to prepare suitable samples for thermoelectric (TE) characterization which created the core of this paper. Comparison of the figure-of-merit ZT, representative of the efficiency of thermoelectric performance, show that the scaling process of mechanochemical synthesis leads to the similar values than using laboratory methods. This makes the cost effective production of Cu-based sulfides as prospective energy materials for converting heat to electricity feasible. Several new concepts have been developed involving combinations of natural and synthetic species (tetrahedrite) and nanocomposite formation (tetrahedrite/digenite, mawsonite/stannite) offer sustainable approaches in solid state chemistry. Mechanochemical synthesis is selected as a simple, one-pot and facile solid-state synthesis of thermoelectric materials with the capability to reduce, or even eliminate solvents, 3 toxic gases, high temperatures with controllable enhanced yields. The synthesis is environmentally friendly and essentially waste-free. The obtained results illustrate the possibility of large-scale deployment of energy-related materials.

The paper deals with the stability of centerline inhomogenity of continuously cast slabs and hot rolled products. The centerline segregation is a disadvantageous failure of slabs which can affect the quality properties of the final products. During hot rolling of slabs the centerline segregation pattern will become thin and stretch and it can also be detected in the middle part of heavy plates and coils. It is a common experience that the centerline segregation of heavy plates can not be easily decreased by post heat treatment. The pattern of the centerline segregation was modeled physically by preparing a sandwich structure of steel plates with different levels of carbon and alloying elements. Homogenization experiments were performed and the samples were examined metallographically. Diffusional calculations proved the governing role of carbon activity which is influenced by the distribution of alloying elements.

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