This article provides a nano (hyperlocal) view of climate change mitigation by viewing regenerative organizing through the eyes (as well as bodies and senses, etc.) of the households engaged in community-based energy projects. By showing what humans make up for in the largely absent relationship between nature and technology in these projects, we envision an incremental extension of the literature on community-based energy. The radically different contribution we aim to make is a tripartite imbrication that brings in natural agency alongside the human and the technical but specifies precisely how nano (smaller than micro) embodied practices afford mis- and realignments. https://doi.org/10.1177/1086026619886841 LinkedIn: https://www.linkedin.com/in/helenkopnina/
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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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Synthetic fibers, mainly polyethylene terephthalate (PET), polyamide (PA), polyacrylonitrile (PAN) and polypropylene (PP), are the most widely used polymers in the textile industry. These fibers surpass the production of natural fibers with a market share of 54.4%. The advantages of these fibers are their high modulus and strength, stiffness, stretch or elasticity, wrinkle and abrasion resistances, relatively low cost, convenient processing, tailorable performance and easy recycling. The downside to synthetic fibers use are reduced wearing comfort, build-up of electrostatic charge, the tendency to pill, difficulties in finishing, poor soil release properties and low dyeability. These disadvantages are largely associated with their hydrophobic nature. To render their surfaces hydrophilic, various physical, chemical and bulk modification methods are employed to mimic the advantageous properties of their natural counterparts. This review is focused on the application of recent methods for the modification of synthetic textiles using physical methods (corona discharge, plasma, laser, electron beam and neutron irradiations), chemical methods (ozone-gas treatment, supercritical carbon dioxide technique, vapor deposition, surface grafting, enzymatic modification, sol-gel technique, layer-by-layer deposition of nano-materials, micro-encapsulation method and treatment with different reagents) and bulk modification methods by blending polymers with different compounds in extrusion to absorb different colorants. Nowadays, the bulk and surface functionalization of synthetic fibers for various applications is considered as one of the best methods for modern textile finishing processes (Tomasino, 1992). This last stage of textile processing has employed new routes to demonstrate the great potential of nano-science and technology for this industry (Lewin, 2007). Combination of physical technologies and nano-science enhances the durability of textile materials against washing, ultraviolet radiation, friction, abrasion, tension and fading (Kirk–Othmer, 1998). European methods for application of new functional finishing materials must meet high ethical demands for environmental-friendly processing (Fourne, 1999). For this purpose the process of textile finishing is optimized by different researchers in new findings (Elices & Llorca, 2002). Application of inorganic and organic nano-particles have enhanced synthetic fibers attributes, such as softness, durability, breathability, water repellency, fire retardancy and antimicrobial properties (Franz, 2003; McIntyre, 2005; Xanthos, 2005). This review article gives an application overview of various physical and chemical methods of inorganic and organic structured material as potential modifying agents of textiles with emphasis on dyeability enhancements. The composition of synthetic fibers includes polypropylene (PP), polyethylene terephthalate (PET), polyamides (PA) or polyacrylonitrile (PAN). Synthetic fibers already hold a 54% market share in the fiber market. Of this market share, PET alone accounts for almost 50% of all fiber materials in 2008 (Gubitz & Cavaco-Paulo, 2008). Polypropylene, a major component for the nonwovens market accounts for 10% of the market share of both natural and synthetic fibers worldwide (INDA, 2008 and Aizenshtein, 2008). It is apparent that synthetic polymers have unique properties, such as high uniformity, mechanical strength and resistance to chemicals or abrasion. However, high hydrophobicity, the build-up of static charges, poor breathability, and resistant to finishing are undesirable properties of synthetic materials (Gubitz & Cavaco-Paulo, 2008). Synthetic textile fibers typically undergo a variety of pre-treatments before dyeing and printing is feasible. Compared to their cotton counterparts, fabrics made from synthetic fibers undergo mild scouring before dyeing. Nonetheless, these treatments still create undesirable process conditions wh
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In de zomer van 2005 drongen Amerikaanse wetenschappers aan op de ontwikkeling van een nationale strategie op het terrein van materials science & engineering (MSE). De National Research Council (NRC) van de National Academy of Sciences (NAS) had kort aarvoor het rapport ’Globalization of Materials R&D: Time for a National Strategy’ uitgebracht. In dit rapport ging het om een antwoord op de vraag ‘Waar staan de VS in vergelijking met de rest van wereld?’, ofwel ‘Zijn de VS nog steeds leidend op de verschillende materiaalgebieden of nemen andere landen deze positie over?’ De snelle opkomst van het materialenonderzoek in landen, zoals China en het groeiend onderzoek in Europa vormen immers voor de VS een geduchtere concurrentie dan ooit. Volgens dit rapport is de positie in composieten en superlegeringen dan ook zodanig afgenomen dat Amerika nog nauwelijks de vruchten kan plukken van de elbelovende ontwikkelingen op dit terrein. Ook de positie op het gebied van katalysatoren is vrijwel geheel verdwenen. Vaak is de kennis nog wel aanwezig maar de kracht om die kennis commercieel te benutten ontbreekt. Bedrijven kunnen dan de academische kennis niet meer omzetten in een winstgevende toepassing. Hoewel het vakgebied materials science & engineering in de VS niet meer over de hele linie aan de top van de wereld staat, is de Amerikaanse positie op de meeste terreinen van de materiaalwetenschappen onbetwist. Recente hoogtepunten zijn ruimschoots voorhanden, zoals het maken van grafeen, de verschillende toepassingen van anokoolstofbuisjes, de ontdekking van metamaterialen en het nabootsen van verschijnselen uit de natuur zoals de hechting van de poten van de gekko aan de ondergrond. De National Science Foundation speelt een belangrijke bij de financiering en valorisatie van onderzoek. Verschillende programma’s, waaronder het Materials Science Research and Engineering Centers programma, spelen een grote rol in kennisoverdracht naar bedrijfsleven en maatschappij. Michiel Scheffer is, tijdens zijn vijf maanden verblijf, in de Verenigde Staten zelf op zoek gegaan naar de Amerikaanse positie en heeft met veel onderzoekers gesproken. Ook hij heeft ontdekt dat er nog vele hoogtepunten en sterkten in het Amerikaanse materialenonderzoek te vinden zijn, waarvan hij in deze bundel enthousiast en gedetailleerd verslag doet.
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This study introduces a detailed method for analyzing the buckling behavior of laminated composite structures strengthened with multi-walled carbon nanotubes (MWCNTs). We propose a multi-scale analysis that combines analytical and computational techniques to assess the mechanical performance of MWCNT-reinforced composites under combined moisture, temperature, and mechanical stress conditions. The Halpin-Tsai equations are used to calculate the overall stiffness properties of the nano-enhanced matrix, considering factors like MWCNT clustering, alignment, and curvature. Additionally, we incorporate the nanoscopic, size-dependent features of MWCNTs into our model. The Chamis micromechanical formulas are applied to determine the individual elastic properties of the nanocomposite layers, considering the impacts of temperature and moisture. We then explore how variables such as MWCNT content and size, along with temperature and moisture levels, influence the critical buckling load of MWCNT-based laminated composite beams and plates using our multi-scale model. Our results are successfully compared with existing experimental and theoretical data to validate our approach. The developed method offers significant insights for the design and optimization of MWCNT-reinforced composites, potentially benefiting various engineering fields, including aerospace and automotive industries.
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Bespreking van onderzoek van Erik Danen in ‘Waar wij trots op zijn. De ontdekkingen van 2011’ van de Universiteit Leiden Faculteit der Wiskunde & Natuurwetenschappen. Celbioloog Erik Danen doet onderzoek naar de verwoestende – maar in evolutionaire termen ook wonderlijke – strategieën van de kankercel. Met welke trucs verspreiden kankercellen zich door het lichaam? Hoe overleven ze een aanval van een chemokuur? En hoe wrang is het dat de één procent cellen die de therapie overleeft vervolgens dubbelhard terugslaat.
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Bespreking van onderzoek van Anton Akhmerov in ‘Waar wij trots op zijn. De ontdekkingen van 2011’ van de Universiteit Leiden Faculteit der Wiskunde & Natuurwetenschappen. De Leidse theoretisch natuurkundige Anton Akhmerov promoveerde in mei op een onderzoek naar functionele toepassingen van grafeen, een eenlaags koolstofmateriaal dat de afgelopen jaren volop in de belangstelling staat. Daarnaast werkte hij ook nog aan quantumcomputers, omdat hij tijd over had in zijn onderzoek.
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Het gebruik van eenheden zal in de toekomst in belangrijke mate worden beïnvloed door de toepassing van het SI (het Internationale Stelsel van Eenheden). Op 1 JanuarI 1978 werd een gewijzigd artikel van de ijkwet van kracht dat het gebruik verplicht stelt van uitsluitend door de wet erkende eenheden - en dat zijn overwegend de eenheden van het SI - 'in de uitoefening van een beroep of bedrijf bij het vragen, het aanbieden of het leveren van goederen of diensten'.
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Droop control is used for power management in DC grids. Based on the level of the DC grid voltage, the amount of power regulated to or from the appliance is regulated such, that power management is possible. The Universal 4 Leg is a laboratory setup for studying the functionality of a grid manager for power management. It has four independent outputs that can be regulated with pulse width modulation to control the power flow between the DC grid and for example, a rechargeable battery, solar panel or any passive load like lighting or heating.
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The paper introduced an automatic score detection model using object detection techniques. The performance of sevenmodels belonging to two different architectural setups was compared. Models like YOLOv8n, YOLOv8s, YOLOv8m, RetinaNet-50, and RetinaNet-101 are single-shot detectors, while Faster RCNN-50 and Faster RCNN-101 belong to the two-shot detectors category. The dataset was manually captured from the shooting range and expanded by generating more versatile data using Python code. Before the dataset was trained to develop models, it was resized (640x640) and augmented using Roboflow API. The trained models were then assessed on the test dataset, and their performance was compared using matrices like mAP50, mAP50-90, precision, and recall. The results showed that YOLOv8 models can detect multiple objects with good confidence scores.
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