Designing lead-free piezoelectric ceramics with tailored electrical properties remains a critical challenge for various applications. In this paper we present a novel methodology integrating Machine Learning (ML) and optimization procedures to fine-tune electrical properties in lead-free (1-x) Na0.5 Bi0.5 TiO3 - x CaTiO3 piezoelectric ceramics. A comprehensive dataset of dielectric measurements serves as the foundation for training ML models that accurately predict the permittivity (𝜀′) and dielectric loss (tan 𝛿) as functions of Ca2+concentration (x % Ca), temperature and frequency. Two ML techniques are evaluated: random forest regression, and Multi-Layer Perceptron neural network Regression (MLPR). The MLPR model exhibited a superior regression performance, achieving a correlation coefficient of 0.931 and a root mean squared error of 0.029. The MLPR was then optimized by the Non-dominated Sorting Genetic Algorithm II (NSGA-II) to maximizes 𝜀′ while minimizes tan 𝛿. Within the NSGA-II framework, the optimal values were found at the Pareto curve knee, corresponding to a frequency, temperature, and x % Ca of 609.739 kHz, 398.15 K, and 6.10, respectively, resulting in 𝜀′ equal to 857.87 and tan 𝛿 equal to 0.0120. This approach demonstrates the effectiveness of combining ML andoptimization for designing the electrical properties of piezoelectric ceramics, paving the way for more efficient and targeted material development.
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This whitepaper explores what the impact is of the operating system (OS) of a smartphone on its lifespan, costs and environmental impact.
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Report in English on the results of the international Master Class by Stadslab on intercultural park design. The case described is a design for for a park in Eastern Ukrainian city of Melitopol. A redevelopment strategy is proposed for its historic Gorky Park (1936). The book also contains essays by intercultural cities expert Phil Wood and introductions by Marc Glaudemans, Beatriz Ramo and Olexandr Butsenko.
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Recent studies on urban policy responses to increasing tourism have moved beyond the physical impact of tourism to also include the way tourism is framed by social movements. This paper contributes to this line of research with a focus on frame resonance: the extent to which frames strike a responsive chord with the public in general and policymakers in particular. We introduce a specific form of frame amplification through cultural resonance; the appeal to pre-existing societal beliefs. Using an analysis of policy documents, print, online and social media, we demonstrate that frames around tourist shops in Amsterdam appealed to pre-existing beliefs that portray the inner city as: a delicate mix of functions, an infrastructure for criminal activities, and a business card reflecting the city’s quality of place. These beliefs amplified frame resonance to such an extent that they convinced an initially reluctant local government to ban tourist shops from the inner city, a policy that undermines the accessibility and inclusivity of urban spaces that the local government aims to promote (SDG 11). This suggests that the contingencies in the local context that enable or foreclose the cultural resonance of frames are essential in understanding policy responses to touristification.
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Sustainable consumption is interlinked with sustainable production. This chapter will introduce the closed-loop production, the circular economy, the steady state economy, and Cradle to Cradle (C2C) models of production. It will reflect on the key blockages to a meaningful sustainable production and how these could be overcome, particularly in the context of business education. The case study of the course for bachelor’s students within International Business Management Studies (IBMS) program at three Universities of Applied Science (vocational schools), and at Leiden University College in The Netherlands will be discussed. Student teams from these schools were given the assignment to make a business plan for a selected sponsor company in order to advise them how to make a transition from a linear to circular economy model. These case studies will illustrate the opportunities as well as potential pitfalls of the closed loop production models. The results of case studies’ analysis show that there was a mismatch between expectations of the sponsor companies and those of students on the one hand and a mismatch between theory and practice on the other hand. The former mismatch is explained by the fact that the sponsor companies have experienced a number of practical constraints when confronted with the need for the radical overhaul of established practices within the entire supply chain and students have rarely considered the financial viability of the "ideal scenarios" of linear-circular transitions. The latter mismatch applies to what students had learned about macro-economic theory and the application through micro-economic scenarios in small companies. https://www.springer.com/gp/book/9783319656076 LinkedIn: https://www.linkedin.com/in/helenkopnina/
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This chapter will introduce the circular economy (CE) and Cradle to Cradle (C2C) models of sustainable production. It will reflect on the key blockages to a meaningful sustainable production and how these could be overcome, particularly in the context of business education. The case study of the course for bachelor’s students within International Business Management Studies (IBMS), and at University College in The Netherlands will be discussed. These case studies will illustrate the opportunities as well as potential pitfalls of the closed loop production models. The results of case studies’ analysis show that there was a mismatch between expectations of the sponsor companies and those of students on the one hand and a mismatch between theory and practice on the other hand. Helpful directions for future research and teaching practice are outlined. https://www.springer.com/gp/book/9783319713113#aboutBook https://www.linkedin.com/in/helenkopnina/
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This book seeks to communicate what we learned, what I learned, in the hope that readers (particularly musicians in training) can find ways to learn for themselves as they challenge themselves to try new, and different, things.
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The present study examined efficacy of traditional Chinese medicine (TCM) treatment in Dutch children with asthma in areas with differing air pollution. The study results indicate that TCM treatment of children living in more polluted urban area is less successful then that of children living in cleaner air area. http://dx.doi.org/10.5402/2012/547534 https://www.linkedin.com/in/helenkopnina/
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With a market demand for low cost, easy to produce, flexible and portable applications in healthcare, energy, biomedical or electronics markets, large research programs are initiated to develop new technologies to provide this demand with new innovative ideas. One of these fast developing technologies is organic printed electronics. As the term printed electronics implies, functional materials are printed via, e.g. inkjet, flexo or gravure printing techniques, on to a substrate material. Applications are, among others, organic light emitting diodes (OLED), sensors and Lab-on-a-chip devices. For all these applications, in some way, the interaction of fluids with the substrate is of great importance. The most used substrate materials for these low-cost devices are (coated) paper or plastic. Plastic substrates have a relatively low surface energy which frequently leads to poor wetting and/or poor adhesion of the fluids on the substrates during printing and/ or post-processing. Plasma technology has had a long history in treating materials in order to improve wetting or promote adhesion. The µPlasma patterning tool described in this thesis combines a digital inkjet printing platform with an atmospheric dielectric barrier discharge plasma tool. Thus enabling selective and local plasma treatment, at atmospheric pressure, of substrates without the use of any masking materials. In this thesis, we show that dependent on the gas composition the substrate surface can either be functionalized, thus increasing its surface energy, or material can be deposited on the surface, lowering its surface energy. Through XPS and ATR-FTIR analysis of the treated (polymer) substrate surfaces, chemical modification of the surface structure was confirmed. The chemical modification and wetting properties of the treated substrates remained present for at least one month after storage. Localized changes in wettability through µPlasma patterning were obtained with a resolution of 300µm. Next to the control of wettability of an ink on a substrate in printed electronics is the interaction of ink droplets with themselves of importance. In printing applications, coalescence of droplets is standard practice as consecutive droplets are printed onto, or close to each other. Understanding the behaviour of these droplets upon coalescence is therefore important, especially when the ink droplets are of different composition and/or volume. For droplets of equal volume, it was found that dye transport across the coalescence bridge could be fully described by diffusion only. This is as expected, as due to the droplet symmetry on either side of the bridge, the convective flows towards the bridge are of equal size but opposite in direction. For droplets of unequal volume, the symmetry across the bridge is no longer present. Experimental analysis of these merging droplets show that in the early stages of coalescence a convective flow from the small to large droplet is present. Also, a smaller convective flow of shorter duration from the large into the small droplet was identified. The origin of this flow might be due to the presence of vortices along the interface of the bridge, due to the strong transverse flow to open the bridge. To conclude, three potential applications were showcased. In the first application we used µPlasma patterning to create hydrophilic patterns on hydrophobic dodecyl-trichlorosilane (DTS) covered glass. Capillaries for a Lab-on-a-chip device were successfully created by placing two µPlasma patterned glass slides on top of each other separated by scotch tape. In the second application we showcased the production of a RFID tag via inkjet printing. Functional RFID-tags on paper were created via inkjet printing of silver nanoparticle ink connected to an integrated circuit. The optimal operating frequency of the produced tags is in the range of 860-865 MHz, making them usable for the European market, although the small working range of 1 m needs further improvement. Lastly, we showed the production of a chemresistor based gas sensor. In house synthesised polyemeraldine salt (PANi) was coated by hand on top of inkjet printed silver electrodes. The sensor proved to be equally sensitive to ethanol and water vapour, reducing its selectivity in detecting changes in gas composition.
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Recent developments in digital technology and consumer culture have created new opportunities for retail and brand event concepts which create value by offering more than solely marketing or transactions, but rather a place where passion is shared. This chapter will define the concept of ‘fashion space’ and consumer experience, and delves into strategies for creating experiences that both align with a brand’s ethos and identity and build brand communities. It will provide insight on creating strong shared brand experiences that integrate physical and digital spaces, AR and VR. These insights can be used for consumer spaces but also for media and buyer events, runway shows, test labs and showrooms. Since its launch in 2007, international fashion brand COS has focused on creating fashion spaces that build and reinforce a COS fashion community. COS retail stores with their extraordinary architecture, both traditional and contemporary, contribute stories and facilitate intense brand experiences. Moreover, COS’ dedication to share the artistic inspirations of its people led to collaborating on interactive and multi-sensory installations which allow consumers to affectively connect to the brand’s personality and values. Thus, the brand was able to establish itself firmly in the lifestyle of its customers, facilitating and developing their aesthetics and values. This is an Accepted Manuscript of a book chapter published by Routledge/CRC Press in "Communicating Fashion Brands. Theoretical and Practical Perspectives" on 03-03-2020, available online: https://www.routledge.com/Communicating-Fashion-Brands-Theoretical-and-Practical-Perspectives/Huggard-Cope/p/book/9781138613560. LinkedIn: https://nl.linkedin.com/in/overdiek12345
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