105 research outputs found
Fertilization: trade-offs between manure abatement and plant productivity
No full textIn 2005, 30% of the Flemish farms faced a manure excess, while at aggregated level still 9.7% of the emission rights were unused. This means that, despite the various possibilities, Flemish farmers do not succeed in an effective exchange of manure between farms. In current paper is shown how inorganic fertilizer use influences the use and exchange of organic nitrogen. Because of the mutual interdependency between organic and inorganic nitrogen emission rights (or quota), inorganic nitrogen use limits the emission rights for organic nitrogen. Utilisation of these emission rights are analysed as a trade-offs choice between plant productivity (use of inorganic nitrogen) and manure disposal, as the major abatement alternative of manure production. Farmers still prefer inorganic fertilizers because of their effect on plant productivity and income. However, by changing the quota rent of organic nitrogen, the fertilization behaviour can be influenced. A higher quota rent of organic nitrogen would increase the use of manure. This trade-off behaviour seriously influences effectiveness of policies. When the objective is to lower the total nitrogen use, a mere reduction of organic quota can partially be counteracted by a higher inorganic nitrogen use. When the objective is to better spread the manure, increasing the quota rent for deficit farms will increase their acceptance of manure.manure abatement, nutrient emission rights, Tobit model, Crop Production/Industries,
Are EU spatial ex ante coexistence regulations proportional?
No full textThe EU is currently struggling to implement coherent coexistence regulations on genetically modified (GM) and non-GM crops in all member states. While it stresses that any approach needs to be “proportionate to the aim of achieving coexistence”, very few studies have actually attempted to assess whether the proposed spatial ex ante coexistence regulations (SEACERs) satisfy this proportionality condition. In this article, we define proportionality as a functional relationship which is weakly increasing in the incentives for coexistence. We propose a spatial framework based on an existing landscape and introduce the new concept of shadow factor as a measure for the opportunity costs induced by SEACERs. This enables comparing the proportionality of (i) rigid SEACERs which are based on large isolation distances imposed on GM farmers versus (ii) flexible SEACERs based on pollen barrier agreements between neighboring farmers. Our theoretical and empirical findings argue for flexibility as rigid SEACERs violate the proportionality condition and, hence, are not consistent with the objectives of the EU.policy analysis, GIS, shadow factor, Agricultural and Food Policy, Crop Production/Industries,
Prefigurative democracy : protest, social movements and the political institution of society /
No full textIn the wake of protest movements such as Occupy Wall Street and the Spanish 15-M movement, the past decade has seen an increased interest in prefigurative politics: the attempt of activists to already realise or embody their ideal of a future society within their own movements and practices. Engaging with the concept and its history, this book establishes a radical-democratic theory of prefiguration. Van de Sande builds on the work of political theorists as diverse as Hannah Arendt, Ernesto Laclau, Claude Lefort, Rosa Luxemburg, and Judith Butler to reveal the radical and representative role of protest and social movements today. He gives various accounts of how prefigurative practices and movements may continue to have political relevance long after they have ended.Specialized.Also issued in print: 2023.Includes bibliographical references and index.In the wake of protest movements such as Occupy Wall Street and the Spanish 15-M movement, the past decade has seen an increased interest in prefigurative politics: the attempt of activists to already realise or embody their ideal of a future society within their own movements and practices. Engaging with the concept and its history, this book establishes a radical-democratic theory of prefiguration. Van de Sande builds on the work of political theorists as diverse as Hannah Arendt, Ernesto Laclau, Claude Lefort, Rosa Luxemburg, and Judith Butler to reveal the radical and representative role of protest and social movements today. He gives various accounts of how prefigurative practices and movements may continue to have political relevance long after they have ended.Specialized.Description based on online resource; title from PDF title page (viewed on May 2, 2023)
Wat moet eruit komen? Reactie op de kritische bijdrage van Kalmijn en De Graaf
No full textThe article focuses on the views of the author regarding the evaluation of his test book by Mathijs Kalmijn and Paul M. De Graaf meant for measuring professional status. Both Kalmijn and Graff have compared the scales proposed by the author and other scales for measuring professional status. They have claimed that GK-schaal is more effective than that of the author. According to the author, they have based their theoretical foundation of objective scales on training and profession
Compliance in Resource-based Process Models
No full textpeer reviewedExecution of business processes often requires resources, the use of which is usually subject to constraints. In this paper, we study the compliance of business processes with resource usage policies. To this end, we relate the execution of a business process to its resource requirements in terms of resources consumed, produced or blocked by tasks of the business process. Policies specifying constraints on resource usage are specified in the form of obligations and the verification of whether a business process complies with a given resource usage policy is formally studied
Efficiency optimisation of the prototyping process for injection moulding
No full textThis research provides a recommendation for Sonion, a company specialised in the development and production of hearing aids, on the production of moulds for the injection moulding machine. The goal was to develop a process that reduces the cost and the time to manufacture an injection mould while maintaining a similar accuracy as in conventional mould production. Usually, Sonion outsources the production of injected moulded parts, resulting in parts with a tolerance of ~ ±10 µm that cost €15.000 for a 1000 pieces with a delivery time of 6-8 weeks. For Sonion’s development process, which is prototype heavy, this is too expensive and takes too much time. A micro injection moulding machine is acquired to shorten the iteration time of their design process and to reduce cost. Before and during this research, the possibilities of 3D printing the moulds with a thermal resistant resin were being explored. For that reason, 3D printing with these materials was left out of the scope of this project. Although the accuracy for this method is sufficient, it struggles with the high pressure and temperature it is exposed to while injection moulding.After identifying many possible manufacturing methods, the most promising techniques capable of withstanding the injection moulding temperature were chosen and validated through testing, research and consulting experts. For a total of six methods, the physical performance (a combination of accuracy, surface roughness and tool life) and the feasibility (iteration time, cost, form freedom and ease of execution) was determined. From the selected six methods, two were recommended for further exploration and investigation; Micro Metal Casting and Powder Injection Moulding. The other methods fell short due to a lack of accuracy, causing iteration time to be too long and the inability to manufacture certain parts of the mould. The Micro Casting method works on the principle of the lost wax casting and is taken to a higher level by increasing its ability to replicate a shape. Both fully outsourcing the production and in-house production have been tested with similar results; the in-house production being slightly more accurate with a lower surface roughness. Metal moulds can be produced with a tolerance of ±25 µm for a price of around €750 within one to two weeks. It is recommended that for the continuation of this method, first the already acquired moulds are tested and future designs are fully outsourced until higher accuracy and lower surface roughness are required. Powder Injection Moulding is a method capable of moulding metal parts at a temperature of 190 °C by mixing a fine metal grain with a polymeric binder and therefore could be used to produce a metal injection mould. In theory, the 3D printed moulds should be able to resist this temperature since it is relatively low. After moulding, the part goes into the oven for the polymer to debind and the grains to be sintered together. A collaboration with the Powder Injection Moulding company Demcon had been setup for testing, but due to misaligning agendas it could not be set in motion. A test with a similar material has been conducted with highly detailed results. It is suggested to explore the possibilities of this method further.Integrated Product Desig
Effects of silver nanoparticle- containing 3D printed antibacterial implants on macrophages
No full textOrthopedic implants used for total joint replacements are under a high clinical demand. Although most total joint replacements are successful, premature failures are still affecting tens of thousands of people annually. The major causes of implant failure are aseptic loosening and bacterial infections. To overcome these issues, multifunctional biomaterials that can on one hand battle implant associated infections (IAI), while on the other hand enhance osseointergration are being researched. Additive manufacturing and surface modification of titanium and its alloys are very promising strategies to enhance osseointergration, as the micro-architectural structures generated by these techniques have been shown to improve bone tissue integration. However, bacteria can more easily evade defense mechanisms in porous structures. To battle possible IAI, silver nanoparticles (AgNPs) can be incorporated into the surface. However, it is crucial that such antibacterial mechanisms do not interfere with tissue regeneration processes or impact cells that play a key role in regulating bone regeneration, such as macrophages. Therefore, the aim of this study was to generate an implant which could inhibit bacterial activity, while preventing adverse effects towards macrophages. 3D printed Ti-6Al-4V implants were modified by plasma electrolytic oxidation (PEO), during which different concentrations of AgNPs were incorporated into the surface. Surfaces were characterized by scanning electron microscopy (SEM) and energy- dispersive X-ray (EDX). The viability of human mesenchymal stem cells, mouse J774A.1 macrophages and primary human macrophages was determined following the culture of each cell type on the surface of implants. Additionally, inflammatory gene and secreted protein levels were determined following the culture of human primary macrophages on the surface of the most promising implant. Finally, antibacterial activity of these implants was investigated. Implants that were surface modified in the presence of 0.3 g AgNPs/L were identified as the most promising implant to support cellular viability. Furthermore, human macrophages cultured on the surface of PEO + 0.3 g AgNPs/L implants had comparable inflammatory gene expression and cytokine production levels compared to cells cultured on implants not containing AgNPS. Moreover, metabolic activity assessment of S. aureus and E. coli in the presence of PEO + 0.3 g AgNPs/L implants showed that E. coli was affected, while S. aureus was not. Interestingly, SEM images showed none of the bacteria were able to colonize the surface, highlighting the generation of an implant which can inhibit bacterial colonization, while not showing adverse effects towards macrophages.Biomedical Engineerin
A study on the stochastic modelling of load balances and the auxiliary power demand of superyachts in an early design phase
No full textDevelopment of a high resolution topography and colour scannner: Applied to the craquelure pattern of paintings
No full textRoute Planning with Breaks and Truck Driving Bans Using Time-Dependent Contraction Hierarchies
No full textMandatory breaks for truck drivers are nowadays scheduled after the route has been decided. However, in some cases it is beneficial to plan these breaks during waiting time caused by truck driving bans. Optimally planning a single break considering driving bans can be done using Dijkstra’s algorithm with multiple labels. This has large effects on predicted travel times: 17% of the analysed routes having a night rest obtain an earlier arrival time by 5 hours on average. However, the computation times of this algorithm are long. A novel heuristic version of time-dependent contraction hierarchies leads to significant reductions in computation times from several seconds to several milliseconds per route. Experiments show that the solutions are still optimal for a representative test set consisting of 10,000 route queries.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.AlgorithmicsTransport and Plannin
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