34 research outputs found

    Energy-efficient casting processes

    Get PDF
    Metal casting is one of the most energy-intensive manufacturing processes that have developed along the evolution of mankind. Although nowadays its scientific and technological aspects are well established, in the context of future resource scarcity and environmental pollution pressures, new studies appear necessary to describe the “foundry of the future” where energy and material efficiency are of great importance to guarantee competitiveness alongside environmental protection. In this chapter, both managerial and technical good practices aimed at implementing energy-efficient casting processes are presented alongside a few examples. The “Small is Beautiful” philosophy is presented as a systematic approach towards energy resilient manufacturing and, potentially, sustainability in the long term. Thus, this chapter aims at providing an overview of the different aspects comprising the state of the art in the industry and examples of research themes in academia about energy-efficient casting processes

    Limited role of spatial selfstructuring in emergent trade-offs during pathogen evolution

    Get PDF
    Pathogen transmission and virulence are main evolutionary variables broadly assumed to be linked through trade-offs. In well-mixed populations, these trade-offs are often ascribed to physiological restrictions, while populations with spatial self-structuring might evolve emergent trade-offs. Here, we reexamine a spatially-explicit, SIR model of the latter kind proposed by Ballegooijen and Boerlijst with the aim of characterising the mechanisms causing the emergence of the trade-off and its structural robustness. Using invadability criteria, we establish the conditions under which an evolutionary feedback between transmission and virulence mediated by pattern formation can poise the system to a critical boundary separating a disordered state (without emergent trade-off) from a self-structured phase (where the trade-off emerges), and analytically calculate the functional shape of the boundary in a certain approximation. Beyond evolutionary parameters, the success of an invasion depends on the size and spatial structure of the invading and invaded populations. Spatial self-structuring is often destroyed when hosts are mobile, changing the evolutionary dynamics to those of a well-mixed population. In a metapopulation scenario, the systematic extinction of the pathogen in the disordered phase may counteract the disruptive effect of host mobility, favour pattern formation and therefore recover the emergent trade-off.This work has been supported by the Spanish Ministerio de EconomĂ­a, Industria y Competitividad and FEDER funds of the EU through grants ViralESS (FIS2014-57686-P and FIS2017-84256-P). The internship of VB was financed by the Severo Ochoa Centers of Excellence Program (SEV-2013-0347)

    Importance and controls of anaerobic ammonium oxidation influenced by riverbed geology

    Get PDF
    Rivers are an important global sink for excess bioavailable nitrogen: they convert approximately 40% of terrestrial N runoff per year (∌47 Tg) to biologically unavailable N 2 gas and return it to the atmosphere. At present, riverine N 2 production is conceptualized and modelled as denitrification. Anaerobic ammonium oxidation, known as anammox, is an alternative pathway of N 2 production important in marine environments, but its contribution to riverine N 2 production is not well understood. Here we use in situ and laboratory measurements of anammox activity using 15 N tracers and molecular analyses of microbial communities to evaluate anammox in clay-, sand-and chalk-dominated river beds in the Hampshire Avon catchment, UK during summer 2013. Abundance of the hzo gene, which encodes an enzyme central to anammox metabolism, varied across the contrasting geologies. Anammox rates were similar across geologies but contributed different proportions of N 2 production because of variation in denitrification rates. In spite of requiring anoxic conditions, anammox, most likely coupled to partial nitrification, contributed up to 58% of in situ N 2 production in oxic, permeable riverbeds. In contrast, denitrification dominated in low-permeability clay-bed rivers, where anammox contributes roughly 7% to the production of N 2 gas. We conclude that anammox can represent an important nitrogen loss pathway in permeable river sediments

    The Alberta Health Technology Assessment (HTA) Ambassador Program: The Development of a Contextually Relevant, Multidisciplinary Clinical Practice Guideline for Non-specific Low Back Pain: A Review

    No full text
    Purpose: To describe the development of a contextually relevant multidisciplinary clinical practice guideline (CPG) for non-specific low back pain (LBP) and to discuss its value to the management of LBP and the practice of physiotherapy

    Surface water linkages regulate trophic interactions in a groundwater food web

    No full text
    Groundwaters are increasingly viewed as resource- limited ecosystems in which fluxes of dissolved organic carbon (DOC) from surface water are effi- ciently mineralized by a consortium of microorgan- isms which are grazed by invertebrates. We tested for the effect of groundwater recharge on resource supply and trophic interactions by measuring phys- ico-chemistry, microbial activity and biomass, structure of bacterial communities and invertebrate density at three sites intensively recharged with surface water. Comparison of measurements made in recharge and control well clusters at each site showed that groundwater recharge significantly increased fluxes of DOC and phosphate, elevated groundwater temperature, and diminished dissolved oxygen (DO). Microbial biomass and activity were significantly higher in recharge well clusters but stimulation of autochthonous microorganisms was not associated with a major shift in bacterial community structure. Invertebrate assemblages were not significantly more abundant in recharge well clusters and did not show any relationship with microbial biomass and activity. Microbial communities were bottom-up regulated by DOC and nutrient fluxes but trophic interactions between microorganisms and invertebrates were apparently limited by environmental stresses, particularly DO depletion and groundwater warming. Hydrological connectivity is a key factor regulating the function of DOC-based groundwater food webs as it influ- ences both resource availability for microorganisms and environmental stresses which affect energy transfer to invertebrates and top-down control on microorganisms
    corecore