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A Lamb wave-based liquid sensor for biomedical applications
No full textThis study presents an AlN-based Lamb wave (A0 mode) liquid sensing device designed for biomedical applications. The Lamb wave device features a 1.5 μm composite membrane consisting of a 500 nm LPCVD SiN and a 1 μm of a c-axis oriented AlN film. Additionally, an innovative 45° rotated IDT design was explored to minimize edge reflections towards the output IDT. Liquid testing experiments, involving IPA, DI water, and D-PBS, were conducted to see if the devices were able to differentiate between these liquids. Results demonstrate that the fabricated Lamb wave devices exhibit sensitivity to mass loading and can distinguish between liquids based on phase, frequency, and gain characteristics. Devices with the rotated IDT design have shown a significant increase in resonance by 15 dB, as well as enhanced sensitivity compared to those with the normal design. Furthermore, devices with the rotated design demonstrated a higher Q factor of 680, indicating superior performance over the normal design (Q factor of 450). These findings suggest that a Lamb wave device with the 45° rotated IDT design holds considerable potential for applications that demand accurate liquid characterization and detection.Electrical Engineerin
The Funnel of Game Design – An Adaptive Game Design Approach for Complex Systems
No full textBackground: In a world of ever-increasing complexity, organizations and people have an ever-increasing need for support systems that help them understand and shape the world around them. While simulation game design derived from the very idea to propose an instrument able to address complexity, seminal approaches dealt with a different level of complexity. In a networked, digitalized world, complexity has increased, and traditional approaches towards designing games show certain shortcomings that have to be overcome. Aim: This article proposes a new process of game design for complex problems and complex systems that can both be used by game designers as well as the scientific community in the field. This process is represented within a framework, based on two parts. The so-called ‘Funnel of Game Design’ based on the IDEAS approach represents the process of problem derivation, while the ‘House of Game Design’ also covers possible steps towards the final game product and process, including de-briefing and evaluation. Method: Based on hands-on experiences and related work, we developed several steps of a game design process (IDEAS approach). In face-to-face interviews, we discussed the first version of the framework with experts in the field of simulation game studies. Results: This process led to the framework presented in this article, which shows the steps of problem derivation as well as challenges that can occur, and proposes adaptive methods to overcome these challenges. The framework includes elements that support the definition of complex problems, and their translation into game designs. Recommendation: We recommend practitioners and scientists to apply the new framework presented here in their efforts to define the underlying problem that should be addressed by an envisioned simulation game, and in translating this into a valid, engaging and meaningful game experience.Policy Analysi
Design capability when visioning for transitions: A case study of a new food system
No full textIn recent years, more designers have been engaging in transitions, for which design expertise is used to develop visions of long-term desirable futures. However, little is known about how design expertise is positioned in transition visioning processes. In this case study, we follow a design agency in envisioning a future food system for a consortium working on the food transition. Based on our findings, we unpack several tensions that emerge between the transition context and design expertise. Such as the tension for designers to explore alternative futures that challenge the current system yet support stakeholders in seeing their place in the future. We conclude by reflecting on avenues for methodological development to optimally position design expertise for visioning in transitions.Design Aesthetic
Design Thinking Tools to Catalyse Sustainable Circular Innovation
No full textDesign thinking is an innovation approach for organisations aiming to solve complex and open-ended problems, including those arising in the transition from a linear to a circular economic system. Although the importance has been recognised in business and academia, to date, insight is lacking on how design thinking can be applied within circular innovation specifically. We investigate the following research question: How can design thinking tools catalyse sustainable circular innovation? Based on the literature, we first create a framework that characterises design thinking principles, criteria and phases that could support circular innovation. The design thinking phases are ideate and design, implement and test, and evaluate and improve. The criteria include desirability, feasibility, viability and sustainability, and circularity. Finally, we identify the following principles that make design thinking suitable to tackle complex circular innovation challenges: human-centred, future-oriented, holistic, co-creative, and experimental. Consequently, against this framework, we map 11 tools that are suitable to catalyse circular innovation theory into practice through design thinking. Finally, we reflect on the future of research and practice around this subject.The publication was funded by the University of Eastern Finland, Tampere University, LUT University, and the University of Turku.Design for Sustainabilit
Sustainable urban logistics: A case study of waterway integration in Amsterdam
No full textThis paper tackles the growing challenges in urban logistics by presenting an optimal distribution network that integrates urban waterways and last-mile delivery, tailored for cities boasting extensive waterway networks. We examine Amsterdam's city center as a case study, prompted by the strain on quay walls, congestion, and emissions, urging a reevaluation of its urban logistics design. We formulate the problem as a two-echelon location routing problem with time windows and introduce a hybrid solution approach for effective resolution. Our algorithm consistently outperforms existing methods, with a superior solution quality, demonstrating its effectiveness across established and newly developed benchmark instances. In our case study, we evaluate the benefits of transitioning from a roadway-centric to a waterway-based system, showcasing significant cost savings (approximately 28 %), reductions in vehicle weight (approximately 43 %), and minimized travel distances (approximately 80 %) within the city center. The integration of electric vehicles enhances environmental sustainability, resulting in a total daily emission reduction of 43.46 kg. Our study underscores the untapped potential of inland waterways in easing urban logistics challenges. Inspired by Amsterdam's experience, global cities can adopt innovative approaches for sustainable logistics, providing valuable insights for managers striving to enhance efficiency, cut costs, and promote sustainable transportation practices.Rivers, Ports, Waterways and Dredging Engineerin
The present and future contribution of ships to the underwater soundscape
No full textSince the industrial revolution the ocean has become noisier. The global increase in shipping is one of the main contributors to this. In some regions, shipping contributed to an increase in ambient noise of several decibels, especially at low frequencies (10 to 100 Hz). Such an increase can have a substantial negative impact on fish, invertebrates, marine mammals and birds interfering with key life functions (e.g. foraging, mating, resting, etc.). Consequently, engineers are investigating ways to reduce the noise emitted by vessels when designing new ships. At the same time, since the industrial revolution (starting around 1760) greenhouse gas emissions have increased the atmospheric carbon dioxide fraction x(CO2) by more than 100 μmol mol-1. The ocean uptake of approximately one third of the emitted CO2 decreased the average global surface ocean pH from 8.21 to 8.10. This decrease is modifying sound propagation, especially sound absorption at the frequencies affected by shipping noise lower than 10 kHz, making the future ocean potentially noisier. There are also other climate change effects that may influence sound propagation. Sea surface warming might alter the depth of the deep sound speed channel, ice melting could locally decrease salinity and more frequent storms and higher wind speed alter the depth of the thermocline. In particular, modification of the sound speed profile can lead to the appearance of new ducts making specific depths noisier. In addition, ice melting and the increase in seawater temperature will open new shipping routes at the poles increasing anthropogenic noise in these regions. This review aims to discuss parameters that might change in the coming decades, focusing on the contribution of shipping, climate change and economic and technical developments to the future underwater soundscape in the ocean. Examples are given, contrasting the open ocean and the shallow seas. Apart from the changes in sound propagation, this review will also discuss the effects of water quality on ship-radiated noise with a focus on propeller cavitation noise.Ship Hydromechanics and StructuresFluid Mechanic
Transformatie naar Woningen
No full textOm het woningtekort op te lossen moeten er jaarlijks zo’n 90.000 nieuwbouwwoningen aan het woningbestand worden toegevoegd. Transformatie van leegstaande gebouwen en herbestemming naar woningen draagt bij aan de oplossing hiervoor. Transformatie werd tot rond 2014 gezien als een oplossing voor de leegstand op de kantorenmarkt, die in de periode 2001–2013 hoog opliep, landelijk van rond 5% in 2001 tot bijna 15% in 2013. De hoge leegstand was mede het gevolg van de dotcom-crisis en de financiële crisis, die samen met technologische ontwikkelingen en een toename in flexwerken leidden tot minder benodigde vierkante meters kantoren, terwijl er juist een overschot aan kantoren werd ontwikkeld en gebouwd.Rond 2014 is een kantelpunt zichtbaar geworden. Transformatie werd steeds vaker gemotiveerd door de vraagzijde van de woningmarkt en niet meer door de aanbodzijde van de kantorenmarkt. De aandacht voor duurzaam bouwen en het verduurzamen van de bestaande gebouwenvoorraad nam toe. In het boek Transformatie van kantoorgebouwen uit 2007 werd duurzaamheid nauwelijks genoemd. Hooguit werd transformatie vermeld als intrinsiek duurzaam, omdat het gebouw werd hergebruikt. Door toegenomen energiekosten en kosten van bouwmaterialen, en door de klimaatcrisis zijn duurzaamheidsaspecten zoals energie-efficiënt, circulair en aanpasbaar bouwen echter veel belangrijker geworden, hoewel ze nog niet overal worden toegepast.Nederland kent een grote vraag naar woningen, maar daarnaast staan veel gebouwen leeg. Op veel plekken in de Randstad staan verouderde kantoorgebouwen waar geen vraag meer naar is. In het hele land komen kerken leeg te staan door vergrijzing en ontkerkelijking. Door verplaatsing van industrie uit de binnensteden naar beter bereikbare locaties of naar het buitenland verliest industrieel vastgoed zijn functie. Schoolgebouwen komen leeg te staan door vergrijzing van de buurt. Ziekenhuizen komen leeg te staan door de invoering van nieuwe zorgconcepten en schaalvergroting. Veel winkels komen leeg te staan door centralisatie en online winkelen. Gebouwen oorspronkelijk gebouwd voor deze (en andere) functies kunnen worden getransformeerd naar woningen.Versmelting van oud en nieuw draagt bij aan behoud van identiteit. Wanneer ook nog eens sprake is van architectonisch interessante gebouwen draagt transformatie bij aan behoud van het cultureel erfgoed. Transformatie kan bijdragen aan verduurzaming van de gebouwenvoorraad en het reduceren van grondstoffengebruik en sloopafval. Transformatie zou jaarlijks 10-15% van de woningproductie kunnen bijdragen.Real Estate ManagementUrban Development ManagementSupport Management in the Built Environmen
Integrated multi-proxy source-to-sink analysis of Late Barremian (Lower Cretaceous) clastic systems in the Essaouira-Agadir Basin
No full textThis study investigates the provenance of the continental and marine Late Barremian clastics of the Bouzergoun Formation, exposed in the Essaouira-Agadir Basin (EAB). Thin section petrography, Scanning Electron Micrography, heavy minerals analysis, and detrital zircon dating were conducted and integrated with a large dataset of published Low-Temperature Thermochronology (LTT) studies to reconstruct the associated source-to-sink system(s). The results constrain the source and size of the system, and composition of deposited clastics, and investigate the mechanism for delivery of coarse clastics into the offshore domain, a key target for hydrocarbon exploration. The homogeneity of rock composition fingerprints throughout the basin indicates a common provenance for both the northern and southern studied transects. Hinterland analysis based on LTT data identifies the Western Meseta and Massif Ancien de Marrakech (MAM) regions as the only possible source candidates exhuming during the Late Barremian, confirmed by detrital zircon geochronology. Heavy mineral populations reveal partly recycled sediment including a probable igneous source. Rock fragment populations comprise limestones, sandstones, and volcanic composition, which correlate with lithologies of the MAM. The integration of all data suggests a best-fit model for the Late Barremian of a source-to-sink system of moderate size (200–300 km long), dominantly sourced from the MAM (western High Atlas). This provided a sand-rich mix of sediment resulting from the erosion of exhuming Triassic continental basins, with associated clays from the weathering of basalts and Triassic/Jurassic mudstones. Late Barremian eustatic sea level fall, together with regional uplift in the hinterland, is interpreted to have resulted in a forced regression that allowed the system to prograde towards the slope margin, offering enhanced potential for sand delivery into the deep offshore domain. Seismic imaging offshore provides tentative interpretation of synchronous high reflectivity deepwater channels located in structural lows controlled by diapiric salt movement. The Mesetian domain was likely undergoing denudation at the same time and shedding clastic-rich sediments to the northern part of the EAB, beyond the studied region. Sediment supply from the MAM may be mixed with the Mesetian sands to the northern part of the EAB and tentatively in the offshore Essaouira.Applied Geolog
Development of a hazard risk map for assessing pedestrian risk in urban flash floods: A case study in Cúcuta, Colombia
No full textThe rapid growth of impervious areas in urban basins worldwide has increased the number of impermeable surfaces in cities, leading to severe flooding and significant economic losses for civilians. This trend highlights the urgent need for methodologies that assess flood hazards and specifically address the direct impact on pedestrians, which is often overlooked in traditional flood hazard analyses. This study aims to evaluate a methodology for assessing the risk to pedestrians from hydrodynamic forces during urban floods, with a specific focus on Cúcuta, Colombia. The methodology couples research outcomes from other studies on the impact of floodwaters on individuals of different ages and sizes with 1D/2D hydrological modeling. Advanced computational algorithms for image recognition were used to measure water levels at 5-s intervals on November 6, 2020, using drones for digital elevation model data collection. In Cúcuta, where flood risk is high and drainage infrastructure is limited, the PCSWMM (Computer-based Urban Stormwater Management Model) was calibrated and validated to simulate extreme flood events. The model incorporated urban infrastructure details and geomorphological parameters of Cúcuta's urban basin. Four return periods (5, 10, 50, 100), with extreme rainfall of 3 h, were used to estimate the variability of the risk map. The output of the model was analyzed, and an integrated and time-varying comparison of the results was done. Results show that the regions of high-water depth and high velocity could vary significantly along the duration of the different extreme events. Also, from 5 to 100 years return period, the percentage of area at risk increased from 9.6% to 16.6%. The pedestrian sensitivity appears much higher than the increase in velocities or water depth individually. This study identified medium to high-risk locations, which are dynamic in time. We can conclude dynamics are spatiotemporal, and the added information layer of pedestrians brings vulnerability information that is also dynamic. Areas of immediate concern in Cúcuta can enhance pedestrian safety during flash flood events. The spatiotemporal variation of patterns requires further studies to map trajectories and sequences that machine learning models could capture.Urban Desig
A DfT Strategy for Guaranteeing ReRAM’s Quality after Manufacturing
No full textMemristive devices have become promising candidates to complement the CMOS technology, due to their CMOS manufacturing process compatibility, zero standby power consumption, high scalability, as well as their capability to implement high-density memories and new computing paradigms. Despite these advantages, memristive devices are susceptible to manufacturing defects that may cause faulty behaviors not observed in CMOS technology, significantly increasing the challenge of testing these novel devices after manufacturing. This work proposes an optimized Design-for-Testability (DfT) strategy based on the introduction of a DfT circuitry that measures the current consumption of Resistive Random Access Memory (ReRAM) cells to detect not only traditional but also unique faults. The new DfT circuitry was validated using a case study composed of a 3x3 word-based ReRAM with peripheral circuitry implemented based on a 130 nm Predictive Technology Model (PTM) library. The obtained results demonstrate the fault detection capability of the proposed strategy with respect to traditional and unique faults. In addition, this paper evaluates the impact related to the DfT circuitry’s introduced overheads as well as the impact of process variation on the resolution of the proposed DfT circuitry.Computer Engineerin