1,076 research outputs found
Suitability analysis for extrusion-based additive manufacturing process
Additive manufacturing (AM) is a widely applied manufacturing paradigm used for the layer-by-layer fabrication of desired components and objects, especially for those with highly intricate geometry. Extrusion-based AM, which is a subcategory of AM processing technologies, is characterized by the facilitation of controlled and successive deposition of feedstock AM materials through the nozzles of printer heads onto a print bed. Extrusion-based AM processing enables design freedom but offers cost efficiency and process simplicity when compared to other AM categories i.e. liquid- and powder-based AM technologies. The extrusion-based AM process has become increasingly widespread over the last two decades because of the expanding material options that can be used in this technology, and its capacity to be hybridised through the addition of multiple printheads or incorporation into a secondary manufacturing system. Despite the promising aspects of the extrusion-based AM process, increasing demands for customised extrusion-based printed products and an expanding range of extrusion-based AM materials create both material- and process-related challenges that limit the suitability of extrusion-based AM processes for some specific applications. Consequently, the principal objective of this review paper is to conduct a suitability analysis of extrusion-based AM processes. The suitability analysis follows a review and discussion about the extrusion-based AM process, and an assessment of easy- and hard-to-print extrusion-based AM materials. This paper, therefore, provides a comprehensive suitability analysis of each extrusion-based AM process while also providing some promising ideas for improving their current suitability levels. The findings and ratings reported in this paper importantly offers viewpoints that would support better futuristic comparisons between developed and developing extrusion-based AM processes, especially as businesses look to adopt the right AM solutions
Welfare of ducks, geese and quail on farm
This Scientific Opinion concerns the welfare of Domestic ducks (Anas platyrhynchos domesticus),Muscovy ducks (Cairina moschata domesticus) and their hybrids (Mule ducks), Domestic geese (Anseranser f. domesticus) and Japanese quail (Coturnix japonica) in relation to the rearing of breeders, birdsfor meat, Muscovy and Mule ducks and Domestic geese for foie gras and layer Japanese quail for eggproduction. The most common husbandry systems (HSs) in the European Union are described for eachanimal species and category. The following welfare consequences are described and assessed for eachspecies: restriction of movement, injuries (bone lesions including fractures and dislocations, soft tissuelesions and integument damage and locomotory disorders including lameness), group stress, inabilityto perform comfort behaviour, inability to perform exploratory or foraging behaviour and inability toexpress maternal behaviour (related to prelaying and nesting behaviours). Animal-based measuresrelevant for the assessment of these welfare consequences were identified and described. The relevanthazards leading to the welfare consequences in the different HSs were identified. Specific factors suchas space allowance (including minimum enclosure area and height) per bird, group size,floor quality,characteristics of nesting facilities and enrichment provided (including access to water to fulfilbiological needs) were assessed in relation to the welfare consequences and, recommendations onhow to prevent the welfare consequences were provided in a quantitative or qualitative way
Systemic Circular Economy Solutions for Fiber Reinforced Composites
This open access book provides an overview of the work undertaken within the FiberEUse project, which developed solutions enhancing the profitability of composite recycling and reuse in value-added products, with a cross-sectorial approach. Glass and carbon fiber reinforced polymers, or composites, are increasingly used as structural materials in many manufacturing sectors like transport, constructions and energy due to their better lightweight and corrosion resistance compared to metals. However, composite recycling is still a challenge since no significant added value in the recycling and reprocessing of composites is demonstrated. FiberEUse developed innovative solutions and business models towards sustainable Circular Economy solutions for post-use composite-made products. Three strategies are presented, namely mechanical recycling of short fibers, thermal recycling of long fibers and modular car parts design for sustainable disassembly and remanufacturing. The validation of the FiberEUse approach within eight industrial demonstrators shows the potentials towards new Circular Economy value-chains for composite materials
Bio-Based Materials: Contribution to Advancing Circular Economy
This reprint focuses on studies dealing with bio-based materials and its contribution to a circular economy. Research dealing with recycling, waste conversion to bio-based products, the development of bio-based composites, and surface treatments on cellulose fibres have been included in this reprint
Alternative Water Supply Systems
This is the final version. Available on open access from IWA Publishing via the DOI in this recordOwing to climate change related uncertainties and anticipated population growth, different parts of the developing and the developed world (particularly urban areas) are experiencing water shortages or flooding and security of fit-for-purpose supplies is becoming a major issue. The emphasis on decentralized alternative water supply systems has increased considerably. Most of the information on such systems is either scattered or focuses on large scale reuse with little consideration given to decentralized small to medium scale systems. Alternative Water Supply Systems brings together recent research into the available and innovative options and additionally shares experiences from a wide range of contexts from both developed and developing countries.
Alternative Water Supply Systems covers technical, social, financial and institutional aspects associated with decentralized alternative water supply systems. These include systems for greywater recycling, rainwater harvesting, recovery of water through condensation and sewer mining. A number of case studies from the UK, the USA, Australia and the developing world are presented to discuss associated environmental and health implications.
The book provides insights into a range of aspects associated with alternative water supply systems and an evidence base (through case studies) on potential water savings and trade-offs. The information organized in the book is aimed at facilitating wider uptake of context specific alternatives at a decentralized scale mainly in urban areas.
This book is a key reference for postgraduate level students and researchers interested in environmental engineering, water resources management, urban planning and resource efficiency, water demand management, building service engineering and sustainable architecture. It provides practical insights for water professionals such as systems designers, operators, and decision makers responsible for planning and delivering sustainable water management in urban areas through the implementation of decentralized water recycling
Advancements in electrical steels: a comprehensive review of microstructure, loss analysis, magnetic properties, alloying elements, and the influence of coatings
Electrical steels play a crucial role in modern electrical devices and power systems due to their exceptional magnetic properties. This comprehensive review delves into the advancements in the field of electrical steels, focusing on key aspects such as microstructure, loss analysis, magnetic properties, alloying elements, and the influence of coatings. The microstructural characteristics of electrical steels are explored in relation to their impact on magnetic behaviour and overall performance. Loss analysis techniques are discussed, highlighting the importance of minimizing energy dissipation in applications. The intricate relationship between magnetic properties and material composition, including the role of alloying elements, is examined to elucidate the mechanisms governing magnetic behaviour. Furthermore, the influence of coatings on the performance of electrical steels is investigated, considering both protection against environmental factors and their impact on magnetic properties. Through a comprehensive synthesis of recent research, this review provides valuable insights into the multifaceted nature of electrical steels and sets the stage for further advancements in their design and application
The performance of high voltage; outdoor insulation in polluted environments
"An iron wire, 12000 feet in length, was suspended about five feet from the ground by silk cords; one end of it was connected to the globe of an electrical machine, and at the other a lead ball was hung in order to perceive when the matter reached it. After five or six turns of the wheel, the matter had passed along the whole wire and communicated its virtue to the ball, which instantly attracted and repelled light bodies. 2. As this ball was equally electrified with every part of the wire, it is probable that the electric matter would instantly pervade a wire of a still greater length, provided we had a proper apparatus for the purpose. 3. Several metals and other conductors were substituted in place of the ball, and all received the electricity in the same manner. The ball and touched with other non-conductors, :when' the finger, gave a luminous spark and as smart a shock as when the end of the wire next to 'the 'gTobe·vas touched. All these effects instantly ceased whenever .. any person not electrified touched any part of the wire and commenced again a few seconds after his hand was withdrawn. The same effects are produced, though with more difficultly, when hair or woollen ropes were substituted in place of the silk ones: But they were entirely stopped by hemp ropes or when the silk ones were wetted.
Wettability, water droplet dynamics and freezing on irregularly roughened stainless-steel surfaces for ice protection application
In the Arctic and other cold environments, ice can jeopardize local infrastructure, hinder field operations, damage buildings, offshore and ship superstructures and threaten life and property. Ice protection techniques are essential for equipment, structures, and personnel in these environments. Passive techniques rely on the physical properties of the target surface to dispose of ice or prevent ice build-up without any required external energy source. As a passive ice protection technology, (super)hydrophobic metallic surfaces can significantly delay the water droplet impact and freezing process. However, hydrophobic surfaces are not always icephobic. The droplet impact dynamics and freezing process on irregularly roughened (super)hydrophobic metal surfaces have not been fully understood. Previous experimental studies have limited the impact and freezing of water droplets on cold surfaces at room temperature. Most experimental and modelling investigations have also been limited to separately studying droplet impingement and freezing processes. Hence, this study aims to investigate dynamic wetting behaviours and freezing processes coupled with the impact dynamics of a water droplet on irregularly roughened metal surfaces experimentally and analytically.
To achieve this, irregularly roughened stainless-steel surfaces are fabricated by applying sandblasting, Zinc electrodeposition, stearic acid coating, and their combinations to receive various water wettability. The combination of electrodeposition and sandblasting can significantly increase the static contact angle from 91° ± 6° to 151° ± 2°, and these techniques can be applied on an industrial scale.
Surface dynamic wetting characterization illustrates the challenges of understanding the wetting dynamics on irregularly roughened surfaces, including dynamic contact angles and pinning that affect the sliding behaviour on inclined surfaces. These effects result in a poor
correlation between the measured dynamic contact angles and the observed critical sliding angles. Significant variations in the values of these dynamic wetting parameters are inherent to the heterogeneity of surface roughness, which limits the utility of standard dynamic wetting criteria. These findings have implications for academic and industrial research that focuses on achieving a uniform wettability of coating materials throughout their service life.
This study examines the droplet impact dynamics and freezing process on the above-fabricated surfaces through experiments and analytical analysis. The freezing delay of water droplets on the metal surfaces is measured in a cold room below the freezing point of water. The experimental results demonstrate that the superhydrophobic surfaces can significantly delay water droplet freezing, with up to a 57.47 ± 5.22 s freezing delay. Also, the freezing delay time increases with the static contact angles of water on the sample surfaces.
Furthermore, droplet impact from a higher distance on the same target surface leads to faster freezing. The heat transfer analysis demonstrates that a poor wetting condition (e.g., on the superhydrophobic surfaces) contributes to a smaller final contact area of a water droplet on the surface. The average freezing rate per unit mass is approximately proportional to the final contact area. This indicates the longer freezing delay on the (super)hydrophobic surfaces.
The analytical framework coupled the droplet impact dynamic and the freezing process. This model can estimate the total freezing delay time for a water droplet impact and freezing on a surface by evaluating the droplet impact and freezing processes. The experimental results validate the analytical predictions, which verify the feasibility of the method and assumptions used in this study. The analytical consideration not only provides a straightforward and valid solution but also simplifies the rather complicated mechanism of the droplet dynamic and freezing process on metal surfaces and provides a directly estimated total freezing delay time under different conditions. This
approach benefits engineers and reduces extensive and sophisticated computations. This fast and effective method for predicting the droplet impact and the freezing process has also filled the gap in the literature.
This comprehensive study of wettability, droplet impact dynamics and freezing processes connects surface wettability and ice repellency by investigating the wetting behaviour of water droplets on irregular rough solid surfaces; at the same time, connecting droplet impact dynamics and freezing delay and providing a better theoretical analysis of droplet impact, subcooling, nucleation, recondensation and solidification processes will benefit the research field
Tunable Functionality of Pure Nano Cu- and Cu-based Oxide Flexible Conductive Thin Film with Superior Surface Modification
Flexible and soft conductive thin film using pure Cu and Cu-based oxide nanostructures equally benefit from the versatility of their assembling individual materials and robustness of device design components. Their small-scale soft conductive thin film made of curved elastomeric bilayers driven by the responsive forces acting by the embedded printed liquid of pure Cu and/or Cu-based oxide nanostructures channels carrying alternating currents of those compact integrated circuits. As such, the localised oxide growth of those complex multiphase thin film architectures is the empirical knowledge that guides to further understanding of many interrelated factors of their intrinsic multiscale physical-electro-chemical interactions characteristics. Although not much literatures have been reported on the soft, flexible pure Cu and Cu-based oxide nanostructured thin films, still, the compelling unusual shapes/forms/construct of such nanostructures in the preparation of those superior functionalities thin film using various curvilinear shapes would seem to establish a predominant foundation in technologically important MEMS/NEMS devices. Herein, this article attempts to summarise the recent advances, challenges, and prospects of employing pure Cu and Cu-based oxide nanostructures in both fundamental and applied tunable functionality of varying dimensionality. Also, special emphasis on the emerging related critical issues and outlook of technical challenges that pave to research improvement opportunities are included
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