1,204 research outputs found
Process and machine system development for the forming of miniature/micro sheet metal products
This paper reports on the current development of the process for the forming of thin sheet-metal micro-parts (t < 50µm) and the corresponding machine system which is part of the research and technological development of an EU funded integrated project - MASMICRO ("Integration of Manufacturing Systems for the Mass-Manufacture of Miniature/Micro-Products" (/www.masmicro.net/). The process development started with qualification of the fundamentals related to the forming of thin sheet-metals in industrial environment, for which a testing machine and several sets of the testing tools were developed. The process was further optimised, followed by new tool designs. Based on the experience gained during the process development, a new forming press which is suitable for industrial, mass-customised production, has been designed
Linking spatial patterns of leaf litterfall and soil nutrients in a tropical forest: a neighborhood approach
Leaf litter represents an important link between tree community composition, forest productivity and biomass, and ecosystem processes. In forests, the spatial distribution of trees and species-specific differences in leaf litter production and quality are likely to cause spatial heterogeneity in nutrient returns to the forest floor and, therefore, in the redistribution of soil nutrients. Using mapped trees and leaf litter data for 12 tree species in a subtropical forest with a well-documented history of land use, we: (1) parameterized spatially explicit models of leaf litter biomass and nutrient deposition; (2) assessed variation in leaf litter inputs across forest areas with different land use legacies; and (3) determined the degree to which the quantity and quality of leaf litter inputs and soil physical characteristics are associated with spatial heterogeneity in soil nutrient ratios (C:N and N:P). The models captured the effects of tree size and location on spatial variation in leaf litterfall (R2 = 0.31–0.79). For all 12 focal species, most of the leaf litter fell less than 5 m away from the source trees, generating fine-scale spatial heterogeneity in leaf litter inputs. Secondary forest species, which dominate areas in earlier successional stages, had lower leaf litter C:N ratios and produced less litter biomass than old-growth specialists. In contrast, P content and N:P ratios did not vary consistently among successional groups. Interspecific variation in leaf litter quality translated into differences in the quantity and quality (C:N) of total leaf litter biomass inputs and among areas with different land use histories. Spatial variation in leaf litter C:N inputs was the major factor associated with heterogeneity in soil C:N ratios relative to soil physical characteristics. In contrast, spatial variation soil N:P was more strongly associated with spatial variation in topography than heterogeneity in leaf litter inputs. The modeling approach presented here can be used to generate prediction surfaces for leaf litter deposition and quality onto the forest floor, a useful tool for understanding soil–vegetation feedbacks. A better understanding of the role of leaf litter inputs from secondary vegetation in restoring soil nutrient stocks will also assist in managing expanding secondary forests in tropical regions
Arbuscular mycorrhizal fungal diversity and natural enemies promote coexistence of tropical tree species
Negative population feedbacks mediated by natural enemies can promote species coexistence at the community scale through disproportionate mortality of numerically dominant (common) tree species. Simultaneously, associations with arbuscular mycorrhizal fungi (AMF) can result in positive effects on tree populations. Coupling data on seedling foliar damage from herbivores and pathogens and DNA sequencing of soil AMF diversity, we assessed the effects of these factors on tree seedling mortality at local (1 m2) and community (16 ha plot) scales in a tropical rainforest in Puerto Rico. At the local scale, AMF diversity in soil counteracted negative effects from foliar damage on seedling mortality. At the community scale, mortality of seedlings of common tree species increased with foliar damage while rare tree species benefited from soil AMF diversity. Together, the effects of foliar damage and soil AMF diversity on seedling mortality might foster tree species coexistence in this forest
New Technology, New Rules for Journalism and a New World of Engagement
UID/CCI/04667/2016The ways in which people learn, communicate and engage in discussion have changed profoundly during the past decade. As Jenkins related in her book, The Convergence Crisis: An Impending Paradigm Shift in Advertising, Millenials do not want to be told the whole story. Rather, they want someone to begin a conversation that will engage others to become participants in the development of that story (2015). Technology now allows that to happen, sometimes with unintended and/or ill consequences, but technology also generates a dynamic potential to create international and interactive discourse aimed at addressing shared global challenges.publishersversionpublishe
Analysis of instabilities in the Basque Coast Geopark coastal cliffs for its environmentally friendly management (Basque-Cantabrian basin, northern Spain)
Coastal cliffs provide a high landscape value to many natural sites around the world. This means that an ever-increasing number of people are attracted to them. At this point, there is a growing need to manage these spaces from the safety of visitors, but with a view to preserving the environment. With this aim, this paper presents an approach to analyze and manage instabilities in these environments, particularly those subjected to significant anthropic activity, which has been implemented in the cliffs of the Basque Coast Geopark. The starting point is a detailed topographic information, obtained from UAV flights, and the identification on site of unstable elements, including their typology, active source areas, dynamics and reach. From this information, the simulation of rockfall processes, which basically correspond to toppling and infinite slope instabilities favored by differential erosion along the coastline, is approached in two and three dimensions. Results allow the design of precise actions by sectors, according to the energy, height and reach of the detached blocks, including barriers, middle slope actions, ditches and information strategies, depending on the different uses of the sectors. Therefore, this approach leads to a more detailed and environmentally friendly management of these environments. © 2021This study has been carried out by the UPV/EHU Research GroupIT-1029/16 (Government of the Basque Country) in the framework of the strategic project ?Analysis of instabilities in coastal environments of the Basque Country? PES-18/97 (University of the Basque Country) and the collaboration of the Basque Coast Geopark (Geoparkea). Finally, the authors are grateful to the reviewers and the handling editor, for the valuable comments that highly improved the paper
Effect of forcing vine regrowth on 'Tempranillo' (Vitis vinifera L.) berry development and quality in Extremadura
In warmer regions, fruit ripening in the wine grape tends to take place during the hottest part of the growing season. This can have negative consequences on the qualitative characteristics of the grape berries at harvest. Forcing vines to regrow can be an aggressive but effective technique to delay the harvest date, but needs to be evaluated carefully in each growing condition. In 2017, in an experimental vineyard in Extremadura, forcing was conducted 3 (F1 treatment) and 22 (F2 treatment) days after anthesis (May 18 and June 6) by hedging growing shoots to seven nodes and removing summer laterals, leaves and primary clusters. Vines grown using conventional practices were used for the Control treatment. Forcing delayed the harvest date from August 22 (Control) to September 14 (F1) and October 19 (F2). Shifting the berry growth period modified the duration of the different fruit development stages. Compared to the Control treatment, the F1 and F2 berries were smaller at harvest, but had similar skin weight percentages; however, the seed weight percentage of the F2 berries was higher. The differences in grape composition observed at harvest between the various treatments were further accentuated in the wines. At harvest, the F2 berries had significantly higher total polyphenol and anthocyanin content than the Control and F1 berries, which had similar values. In the wines, both F1 and F2 characteristics differed considerably from the Control, most notably in the high F2 tannin concentration. These preliminary results from the first year of study indicate the potential of this technique to obtain wine grapes with very different characteristics, offering new viticultural perspectives in warm climate areas
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