• DC grid structure • Control • Switching • Protection • Stability
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The application of DC grids is gaining more attention in office applications. Especially since powering an office desk would not require a high power connection to the main AC grid but could be made sustainable using solar power and battery storage. This would result in fewer converters and further advanced grid utilization. In this paper, a sustainable desk power application is described that can be used for powering typical office appliances such as computers, lighting, and telephones. The desk will be powered by a solar panel and has a battery for energy storage. The applied DC grid includes droop control for power management and can either operate stand-alone or connected to other DC-desks to create a meshed-grid system. A dynamic DC nano-grid is made using multiple self-developed half-bridge circuit boards controlled by microcontrollers. This grid is monitored and controlled using a lightweight network protocol, allowing for online integration. Droop control is used to create dynamic power management, allowing automated control for power consumption and production. Digital control is used to regulate the power flow, and drive other applications, including batteries and solar panels. The practical demonstrative setup is a small-sized desktop with applications built into it, such as a lamp, wireless charging pad, and laptop charge point for devices up to 45W. User control is added in the form of an interactive remote wireless touch panel and power consumption is monitored and stored in the cloud. The paper includes a description of technical implementation as well as power consumption measurements.
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In order to gain a more mature share in the future energy supply, green gas supply chains face some interesting challenges. In this thesis green gas supply chains, based on codigestion of cow manure and maize, are considered. The produced biogas is upgraded to natural gas quality and injected into the existing distribution gas grid and thus replacing natural gas. Literature research showed that relatively much attention has been paid up to now to elements of such supply chains. Research into digestion technology, agricultural aspects of (energy) crops and logistics of biomass are examples of this. This knowledge is indispensable, but how this knowledge should be combined to help understand how future green gas systems may look like, remains a white spot in the current knowledge. This thesis is an effort to fill this gap. A practical but sound way of modeling green gassupply chains was developed, taking costs and sustainability criteria into account. The way such supply chains can deal with season dependent gas demand was also investigated. This research was further expanded into a geographical model to simulate several degrees of natural gas replacement by green gas. Finally, ways to optimize green gas supply chains in terms of energy efficiency and greenhouse gas reduction were explored.
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Publicatie naar aanleiding van de internationale Master Class van Stadslab European Urban Design Laboratory. Onderwerp was het ontwikkelen van een regionale ruimtelijke strategie voor deze Poolse universiteitsstad. In de publicatie, naast de resultaten van de Master Class, ook essays van Ruud Vreeman, Ewa Kipta en Didier Rebois.
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Wind and solar power generation will continue to grow in the energy supply of the future, but its inherent variability (intermittency) requires appropriate energy systems for storing and using power. Storage of possibly temporary excess of power as methane from hydrogen gas and carbon dioxide is a promising option. With electrolysis hydrogen gas can be generated from (renewable) power. The combination of such hydrogen with carbon dioxide results in the energy carrier methane that can be handled well and may may serve as carbon feedstock of the future. Biogas from biomass delivers both methane and carbon dioxide. Anaerobic microorganisms can make additional methane from hydrogen and carbon dioxide in a biomethanation process that compares favourably with its chemical counterpart. Biomethanation for renewable power storage and use makes appropriate use of the existing infrastructure and knowledge base for natural gas. Addition of hydrogen to a dedicated biogas reactor after fermentation optimizes the biomethanation conditions and gives maximum flexibility. The low water solubility of hydrogen gas limits the methane production rate. The use of hollow fibers, nano-bubbles or better-tailored methane-forming microorganisms may overcome this bottleneck. Analyses of patent applications on biomethanation suggest a lot of freedom to operate. Assessment of biomethanation for economic feasibility and environmental value is extremely challenging and will require future data and experiences. Currently biomethanation is not yet economically feasible, but this may be different in the energy systems of the near future.
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The real-time simulation of human crowds has many applications. In a typical crowd simulation, each person ('agent') in the crowd moves towards a goal while adhering to local constraints. Many algorithms exist for specific local ‘steering’ tasks such as collision avoidance or group behavior. However, these do not easily extend to completely new types of behavior, such as circling around another agent or hiding behind an obstacle. They also tend to focus purely on an agent's velocity without explicitly controlling its orientation. This paper presents a novel sketch-based method for modelling and simulating many steering behaviors for agents in a crowd. Central to this is the concept of an interaction field (IF): a vector field that describes the velocities or orientations that agents should use around a given ‘source’ agent or obstacle. An IF can also change dynamically according to parameters, such as the walking speed of the source agent. IFs can be easily combined with other aspects of crowd simulation, such as collision avoidance. Using an implementation of IFs in a real-time crowd simulation framework, we demonstrate the capabilities of IFs in various scenarios. This includes game-like scenarios where the crowd responds to a user-controlled avatar. We also present an interactive tool that computes an IF based on input sketches. This IF editor lets users intuitively and quickly design new types of behavior, without the need for programming extra behavioral rules. We thoroughly evaluate the efficacy of the IF editor through a user study, which demonstrates that our method enables non-expert users to easily enrich any agent-based crowd simulation with new agent interactions.
MULTIFILE
A year later, in 2013, the Westerkwartier Area Cooperative was established – a new form of cooperation at the regional level, involving hundreds of dairy farmers, other SMEs, Terra MBO as the representative of the knowledge institutions in the region, the National Forest Service in the Netherlands (‘Staatsbosbeheer’), the Groningen Countryside Association (‘Landschapsbeheer Groningen’) and, later on, the De Zijlen healthcare institution. A year later, this initiative was followed by the establishment of the Southwest Drenthe Area Cooperative, another formalised multi-stakeholder cooperative on a large scale, bound together by a shared agenda. The members of these two new cooperatives sought to bring together and strengthen local and sectoral initiatives at the regional level. Because of their close cooperation with knowledge institutions, they hoped that practice-based research would yield a lot of results. At the many evening meetings and during workshops, spirited debates were held about new concepts such as bio-based economy, new concepts in food and health, alternative methods of energy production, but also ways of improving the quality of life in the region, strengthening the tourism industry and creating jobs for young people. Those involved were all too aware that the existing educational and research institutes and government agencies, and the organisational structures used by businesses, tend to do more harm than good, which led to the call for Next Education, Next Governance and Next Business. It became apparent from these discussions that there were many knowledge questions to be explored, and the need arose for a permanent link with the knowledge institutions through the establishment of a separate professorship focused on sustainable and cooperative entrepreneurship for the benefit of the entrepreneurs involved as well as for the education sector, the government and the general public. This is how the Sustainable Cooperative Entrepreneurship professorship came about, as part of the Sustainable Financial Management professorship chaired by Dr Margreet Boersma at Hanze University of Applied Sciences Groningen’s School of Financial and Economic Management. I am honoured to be giving this new professorship shape, and I would like to point out that I will not be doing this on my own – I am only the figurehead of a very substantial group of innovative and ambitious entrepreneurs, students, lecturers, public servants, citizens and colleagues. The Innovation Army is marching. And if you are not a part of it yet, now is the time to get involved!
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This paper presents a report of some of the activities of the International Energy Agency's (IEA) Wind TCP Task 39. By identifying best practices in an international collaboration, Task 39 hopes to provide the scientific evidence to inform improved regulations and standards, increasing the effectiveness of quiet wind turbine technology. Task 39 is divided into five separate work packages, which address the broad wind turbine noise topic in successive steps; from wind turbine noise generation (WP2), to airborne noise propagation over large distances (WP3). The assessment of wind turbine noise and its impact on humans is addressed in WP4, while WP5 is dealing with other aspects of perception and acceptance, which may be related to noise. All WPs contribute to a dedicated Work Package on dissemination (WP1). This paper provides an update of activities primarily associated with the socio-psychological aspects of wind turbine noise (WP4 and WP5). Through the consideration of a wide variety of factors, including measurement technologies, auralisation and psychology, the effects on noise perception, annoyance and its impact on wellbeing and health is being further investigated. This paper presents a discussion of the activities of each member country and highlights some of the key research questions that need to be further considered.
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Bitter gourd is also called sopropo, balsam-pear, karela or bitter melon and is a member of the cucumber family (Cucurbitaceae). It is a monoecious, annual, fast-growing and herbaceous creeping plant. The wrinkled fruit of the bitter gourd is consumed as a vegetable and medicine in Asia, East Africa, South America and India. The aim of this bitter gourd cultivation manual is to make this cultivation accessible to Dutch growers and in this way be able to meet market demand. In addition, this cultivation manual aims to provide insight into the standardized production of the medicinal ingredients in the fruit.
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