The seismic assessment of unreinforced masonry (URM) buildings with cavity walls is of high relevance in regions such as in Central and Northern Europe, Australia, New Zealand and China because of the characteristics of the masonry building stock. A cavity wall consists of two separate parallel walls usually connected by metal ties. Cavity walls are particularly vulnerable to earthquakes, as the out-of-plane capacity of each individual leaf is significantly smaller than the one of an equivalent solid wall. This paper presents the results of an experimental campaign conducted by the authors on metal wall tie connections and proposes a mechanical model to predict the cyclic behaviour of these connections. The model has been calibrated by us- ing the experimental results in terms of observed failure modes and force-displacement responses. Results are also presented in statistical format.
The seismic assessment of unreinforced masonry (URM) buildings with cavity walls is of high relevance in regions such as in Central and Northern Europe, Australia, New Zealand and China because of the characteristics of the masonry building stock. A cavity wall consists of two separate parallel walls usually connected by metal ties. Cavity walls are particularly vulnerable to earthquakes, as the out-of-plane capacity of each individual leaf is significantly smaller than the one of an equivalent solid wall. This paper presents the results of an experimental campaign conducted by the authors on metal wall tie connections and proposes a mechanical model to predict the cyclic behaviour of these connections. The model has been calibrated by us- ing the experimental results in terms of observed failure modes and force-displacement responses. Results are also presented in statistical format.
Mexican oregano is a non-timber forest product harvested in natural vegetation and represents an important source of income for rural families. Recent reports have highlighted decreases in natural populations caused by increased harvest intensity. Oregano leaf harvesting is a complex problem, involving different components and views, and has a clear spatial dimension. We proposed an analytical framework based on multi-criteria-multi-objective analyses. GIS tools were used as the platform for managing, displaying and analyzing ecological and socioeconomic information from different sources in order to evaluate land suitability of three different management strategies for two competing land objectives: oregano Harvest and oregano Regeneration. The incorporation of environmental evaluation criteria in the analysis allowed the identification of new potential oregano harvesting areas which were neither reported by harvesters, nor registered during harvesting trips. Socio-economic criteria, such as land tenure, highlighted the fact that a substantial proportion of current oregano harvesting areas are located outside ejido limits resulting in potential conflicts for resource access. The proposed Balanced oregano management strategy, in which the same proportion of suitable area (50%) was assigned to both objectives, represents the most favorable management strategy. This option allows harvesters to continue earning an income from oregano leaf harvest; and at the same time helps in the selection of the best areas for oregano regeneration. It also represents a management strategy with a smaller impact on oregano populations and on the harvesters ́ income, as well as lower monitoring costs. The proposed analytical frame-work may contribute to advance the application of systematic approaches for solving decision-making problems in areas where oregano leaves and other NTFP are harvested.
MULTIFILE
Horticulture crops and plants use only a limited part of the solar spectrum for their growth, the photosynthetically active radiation (PAR); even within PAR, different spectral regions have different functionality for plant growth, and so different light spectra are used to influence different properties of the plant, such as leaves, fruiting, longer stems and other plant properties. Artificial lighting, typically with LEDs, has been used to provide these specified spectra per plant, defined by their light recipe. This light is called steering light. While the natural sunlight provides a much more sustainable and abundant form of energy, however, the solar spectrum is not tuned towards specific plant needs. In this project, we capitalize on recent breakthroughs in nanoscience to optimally shape the solar spectrum, and produce a spectrally selective steering light, i.e. convert the energy of the entire solar spectrum into a spectrum most useful for agriculture and plant growth to utilize the sustainable solar energy to its fullest, and save on artificial lighting and electricity. We will take advantage of the developed light recipes and create a sustainable alternative to LED steering light, using nanomaterials to optimally shape the natural sunlight spectrum, while maintaining the increased yields. As a proof of concept, we are targeting the compactness of ornamental plants and seek to steer the plants’ growth to reduce leaf extension and thus be more valuable. To realize this project the Peter Schall group at the UvA leads this effort together with the university spinout, SolarFoil, whose expertise lies in the development of spectral conversion layers for horticulture. Renolit - a plastic manufacturer and Chemtrix, expert in flow synthesis, provide expertise and technical support to scale the foil, while Ludvig-Svensson, a pioneer in greenhouse climate screens, provides the desired light specifications and tests the foil in a controlled setting.
Nederlandse glastuinbouwbedrijven, onderzoekers en technologie spelen een grote rol in de voedselvoorziening wereldwijd. De productiviteit ligt hier door de kennis en kunde hoog, met een kleine footprint in vergelijking met producenten in andere landen. Met de huidige bevolkingsgroei en druk op veilige en duurzame voedselvoorziening in het achterhoofd, leveren onderzoekers en ondernemers een versterking van de glastuinbouwsector. De inzet van sensoren, data en data-analyse is gewenst om groei en opbrengst beter te monitoren, ziektes beter te bestrijden, en de footprint verder te verkleinen. Nederlandse telers zijn proeftuinen voor deze innovaties: zij experimenteren als eerste, om technologieën of methoden toe te kunnen passen en tegen lagere kosten meer te produceren. Innovatieagenda’s van betrokken topsectoren dragen sterk bij aan deze ontwikkelingen. Dit project stelt data over de plant centraal. Nu heeft een teler data over zijn klimaat, hij of zij ziet zelf iets met de plant gebeuren en past dan klimaat aan. Dit project zorgt voor meer data over de plant zelf, zodat de telers de teelt directer kunnen aansturen, met betere opbrengst en lagere kosten tot gevolg. In dit project wil het consortium van onderzoekers en ondernemers een grote stap zetten naar grootschalige toepassing van sensortechnologie voor het volgen van gewasgroei. Daarvoor moeten te ontwikkelen sensoren zowel low-cost als nauwkeurig zijn. Daarnaast is draadloos en contactloos werken van groot belang. De belangrijkste te meten parameters zijn de kopdikte van het gewas en de Leaf Area Index. Beide parameters samen zeggen iets over de sapstroom en de sapstroom is de belangrijkste parameter voor de groei van het gewas. Dit project is een vliegwiel voor technologieontwikkeling. Resultaten van het onderzoek en de ontwikkeling, met toeleveranciers, kwekers en veredelaars samen, kunnen na dit proeftuin-stadium de technologie verder brengen, vooral naar het buitenland, waar de vraag naar Nederlandse kennis en expertise alsmaar groter wordt.
In dit onderzoek werken de Hanzehogeschool Groningen en The Leaf samen aan het ontwikkelen en testen van een oplossing voor klimaatproblemen in (binnen)steden. Een ‘Leaf’ is een groene pergola die op meerdere thema’s als hittestress, wateroverlast, biodiversiteit en circulariteit inspeelt. Doel van dit onderzoek is om de effectiviteit, haalbaarheid en rendabiliteit van een Leaf in de praktijk te toetsen. Centraal in dit onderzoek staat het ontwikkelen van meerdere prototypes met verschillende karakteristieken, en deze met verschillende onderzoeksmethodes testen en vergelijken. Het onderzoek wordt met een interdisciplinair team van studenten en onderzoekers en ondersteuning van verschillende experts uit de praktijk uitgevoerd.
