A case study on raw material blending for the recycling of ferrous wastes in a blast furnace

The utilisation of ferrous wastes in a blast furnace is a well established recycling process to cope with the enormous amounts of ferrous residues in the iron and steel industry. The further input flows of this process, that is especially coke and fluxes, as well as its output flows, that is pig iron and by-products, are highly dependent on the blending of the ferrous wastes while they differ highly in the revenues gained for the treatment and their chemical composition. So far, no planning approach exists for the blending of the residues on the operational planning level that models the dependency of the costs and revenues on the raw material blend and the thermodynamic reactions in the recycling processes adequately. Therefore we present an approach for this operational production planning problem focusing on an integration of such a sufficiently detailed modelling of the underlying metallurgical processes into the planning model. The basis of our approach is a thermodynamic simulation of the processes. From this simulation we derive linear input-output functions for the relevant material and energy flows by using multiple linear regression. These input–output functions form the core of our blending model developed for the planning task. The model is implemented as an integrated decision support system. Exemplary application results are given. These results validate the approach and show that ecological the economic optimisation leads also to results which are advantageous in terms of resource efficiency and emission reduction. Though developed for a specific recycling process, the methodology can be transferred to other metallurgical (recycling) processes, as well as other parts of the process industries, and is therefore of high relevance.     

Babbling behavior in the sac-winged bat (Saccopteryx bilineata)

Infant babbling in humans and a few other primates plays an important role in allowing the young to practice the adult vocal repertoire during early behavioral development. Vocalizations uttered during babbling resemble, to some degree, the acoustic structure of adult vocalizations and are often produced in long bouts independent of any social context. Similar behavior, termed subsong or plastic song, is known from a variety of songbirds. Here, we show that pups of the sac-winged bat (Saccopteryx bilineata), a species with an unusually large vocal repertoire, produce renditions of all known adult vocalization types during bouts of vocalizations, which appear to be independent of a distinct social context. Babbling occurs in pups of both sexes, even though only adult males, not females, utter all different vocalization types produced in infancy. To our knowledge, this is the first evidence of babbling in a nonprimate mammal and suggests that infant babbling may be necessary for the ontogeny of complex vocal repertoires.     

Questioning complacency: climate change impacts, vulnerability, and adaptation in Norway

Most European assessments of climate change impacts have been carried out on sectors and ecosystems, providing a narrow understanding of what climate change really means for society. Furthermore, the main focus has been on technological adaptations, with less attention paid to the process of climate change adaptation. In this article, we present and analyze findings from recent studies on climate change impacts, vulnerability, and adaptation in Norway, with the aim of identifying the wider social impacts of climate change. Three main lessons can be drawn. First, the potential thresholds and indirect effects may be more important than the direct, sectoral effects. Second, highly sensitive sectors, regions, and communities combine with differential social vulnerability to create both winners and losers. Third, high national levels of adaptive capacity mask the barriers and constraints to adaptation, particularly among those who are most vulnerable to climate change. Based on these results, we question complacency in Norway and other European countries regarding climate change impacts and adaptation. We argue that greater attention needs to be placed on the social context of climate change impacts and on the processes shaping vulnerability and adaptation.     

Temperature and wetland plant species effects on wastewater treatment and root zone oxidation

Constructed wetlands are widely used for wastewater treatment, but there is little information on processes affecting their performance in cold climates, effects of plants on seasonal performance, or plant selection for cold regions. We evaluated the effects of three plant species on seasonal removal of dissolved organic matter (OM) (measured by chemical oxygen demand and dissolved organic carbon) and root zone oxidation status (measured by redox potential [Eh] and sulfate [SO4(2-)]) in subsurface-flow wetland (SSW) microcosms. A series of 20-d incubations of simulated wastewater was conducted during a 28-mo greenhouse study at temperatures from 4 to 24 degrees C. Presence and species of plants strongly affected seasonal differences in OM removal and root zone oxidation. All plants enhanced OM removal compared with unplanted controls, but plant effects and differences among species were much greater at 4 degrees C, during dormancy, than at 24 degrees C, during the growing season. Low temperatures were associated with decreased OM removal in unplanted controls and broadleaf cattail (Typha latifolia L.) microcosms and with increased removal in beaked sedge (Carex rostrata Stokes) and hardstem bulrush [Schoenoplectus acutus (Muhl. ex Bigelow) A. & D. L?ve var. acutus] microcosms. Differences in OM removal corresponded to species' apparent abilities to increase root zone oxygen supply. Sedge and bulrush significantly raised Eh values and SO4(2-) concentrations, particularly at 4 degrees C. These results add to evidence that SSWs can be effective in cold climates and suggest that plant species selection may be especially important to optimizing SSW performance in cold climates.