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Assessing and enhancing the circularity and sustainability of emergency hospital shelters
Get PDFLeading humanitarian organisations strive to enhance the sustainability of their aid to avoid negative impacts on the environment, economy, and society, particularly in low-resource areas. This study explores how the circularity and sustainability of emergency hospital shelters can be assessed using literature, expert interviews, co-creation and design sessions, and pilot testing. The approach combines a qualitative circularity checklist with a quantitative environmental impact assessment, providing valuable input for informed decision-making during procurement and design. The findings reveal that existing buildings are commonly repurposed before importing emergency hospital shelters—finite virgin materials are primarily used for the production of new shelters—and there is a lack of data with which to reflect on end-of-life scenarios. The study recommends enhanced monitoring of the shelter lifecycle through data collection as an input for continuous improvement procedures of design and supply. Crucial are extended stakeholder responsibilities for the entire lifecycle and sector-wide adoption of circularity and sustainability ambitions, mainstreaming approaches and showcasing benefits
Ratoon rice mapping based on Sentinel-1 and Sentinel-2 imagery
Get PDFRice ratooning has gained increasing interest in Asia as a way to boost rice production by allowing two rice harvests from a single growing season. Accurate mapping of this practice can improve rice production estimates. However, current efforts have mainly relied on optical sensors, which are limited by cloud cover, especially during the wet season when ratooning is common. This study systematically assessed the use of optical Sentinel-2, Synthetic Aperture Radar (SAR) Sentinel-1 data and their combination to map ratoon rice crops. Field data were collected in four provinces of the Philippines in 2018–19. Backscatter intensity from Sentinel-1, spectral information, and six commonly used vegetation indices (VIs) from Sentinel-2 were analysed using the Mann-Whitney U significance test to examine differences between the main and ratoon rice crops. Next, we compared the classification performance of decision tree (DT), support vector machine (SVM), and random forest (RF) classifiers. Results show that ratoon and main rice crop significantly differed in VV and VH polarisations, red edge and near-infrared bands, and all VIs. The highest accuracy was achieved with selected features in an RF classifier (overall accuracy of 92 %), compared to SVM (87 %) and DT (81 %). Classification using features from both Sentinel-1 and 2 consistently yielded higher accuracy than using features from one sensor alone. The total planting of ratoon rice was estimated at approximately 223 km2 (±4 % of the wet season rice area). This study demonstrates the value of combining SAR Sentinel-1 and optical Sentinel-2 for ratoon rice mapping
Effects of process parameters on dynamic and static load capacity of EN AW-2024-T3 aluminum alloy joints prepared by friction stir welding
Get PDFThis study investigates the impact of friction-stir welding (FSW) process parameters on the mechanical performance and fracture behavior of EN AW-2024-T3 aluminum alloy joints. A series of static and dynamic mechanical tests were conducted on six welded samples, revealing that the joint strength and fracture characteristics are highly sensitive to FSW parameters, particularly tool rotational rate, pin length, and traverse speed. Sample III, which exhibited the optimal combination of parameters, achieved the highest static load capacity, reaching 98.5% of the raw material's strength. Dynamic testing further confirmed Sample III's superior performance, with the highest recorded load capacity and significant energy absorption, as evidenced by ductile fracture features and high surface roughness. In contrast, Sample V, characterized by an excessive pin length, showed the lowest static and dynamic strength, along with a brittle fracture mode. The surface topography and SEM analysis of fracture surfaces indicated that optimized FSW conditions promote a ductile fracture mode, enhancing joint toughness under dynamic loading. These findings underscore the critical role of process parameter optimization in improving the mechanical properties and fracture resistance of FSW aluminum joints, making them more suitable for applications subjected to static and dynamic loading.</p
Optimization of 3D Printing Parameters for Enhanced Mechanical Strength:Effects of Glass Fiber Reinforcement and Fill Ratio Using RSM and ANOVA
Get PDFThis research aimed to provide valuable insights for future studies and enhance manufacturing processes by investigating the effect of incorporating fibers into 3D printing to improve the mechanical properties of fabricated components. The experimental design was carried out using Design-Expert software, employing the Central Composite Design (CCD) methodology. Seventeen experiments were conducted, with predefined input parameters, layer height, filler ratio, and printing speed, analyzed through the Response Surface Methodology (RSM) using Design-Expert version 12. An Analysis of Variance (ANOVA) revealed that the filler ratio had the most significant effect on fracture strength. The influence of different printing parameters printing speed, layer height, and filler ratio on the mechanical properties and print quality was systematically investigated. The results indicated that the filler ratio was the most critical factor, with a 100% fill ratio yielding the highest tensile strength. Conversely, a 50% fill ratio significantly reduced production costs, but at the expense of mechanical performance. Thus, if strength is the primary requirement, a higher fill ratio is recommended. The effect of printing speed was found to be less significant compared to layer height and filler ratio. The maximum recorded tensile strength was 540.65 N, achieved with a layer height of 0.5 mm, a 100% fill ratio, and a printing speed of 8 mm/s. In contrast, the lowest recorded tensile strength was 389.93 N, observed with a layer height of 0.4 mm, a 50% fill ratio, and a printing speed of 4 mm/s. After applying a transformation function, the data showed good alignment with the normal distribution on the probability plot, indicating that the assumption of normality was satisfied. Additionally, the incorporation of glass fibers significantly enhanced the mechanical strength of the printed samples.</p
Unleashing the potential of Turkish chatbots:a study on the validity and reliability of the bot usability scale
No full textThe objective of this study is to adapt and evaluate the Turkish version of the Chatbot Usability Scale (BUS-11) through a confirmatory factor analysis method. The BUS-11 scale has been established in various languages except for Turkish; thus, its validation and dissemination could serve as a means to improve chatbot interaction satisfaction among the Turkish-speaking population and hence foster growth in Turkey’s conversational agent market. To achieve this aim, seven customer-oriented chatbots were rated on pre-designed tasks by participants. Data collection involved using the Turkish-adapted BUS11 (TBUS-11) to assess individuals’ experiences after interacting with Turkish-speaking chatbots, along with the Turkish version of the UMUX-LITE scale. Results show that TBUS-11 has been demonstrated to be highly reliable with a strong convergent validity with the UMUX-LITE already validated in Turkish. Moreover, the analysis demonstrated that the dataset supported the five-factor structure of the original version of the scale, thus confirming the psychometric properties of the TBUS. The study successfully adapted the BUS-11 into Turkish, providing a reliable and valid tool for assessing chatbot usability in the Turkish-speaking market. This can potentially enhance user satisfaction and promote the growth of conversational agents in Turkiye.</p
The MyFlex-ζ Foot:A Variable Stiffness ESR Ankle-Foot Prosthesis
Get PDFMost commercially available foot prostheses are passive ESR feet, which store and release energy to reduce metabolic costs and improve comfort but cannot adjust to varying walking conditions. In contrast, bionic feet adapt to different tasks but are hindered by high weight, power consumption, and cost. This paper presents MyFlex-ζ, an ESR foot with a variable stiffness system, as a compromise between these two categories. MyFlex-ζadjusts stiffness by varying the sagittal-plane distance between two key points, altering force interactions within the prosthesis and affecting overall stiffness. Clinical tests with three transfemoral amputees evaluated stiffness variation across two sessions: the first subjective, where participants assessed stiffness settings during different tasks, and the second biomechanical, measuring performance parameters. Two participants selected different stiffness settings for various tasks, while the third, with limited perception of stiffness changes, showed less distinction in outcomes. Greater sagittal-plane rotation and higher energy absorption were observed in most tasks with more compliant settings, although one participant's results were limited due to selecting close stiffness settings. Overall, these findings suggest MyFlex-ζoffers adaptability and performance improvements over traditional ESR feet. With further actuation and control system development, MyFlex-ζcould mark significant progress in prosthesis technology.</p
TrackScorer:Skyrmion Logic-in-Memory Accelerator for Tree-Based Ranking Models
No full textRacetrack memories (RTMs) have been shown to have lower leakage power and higher density compared to traditional DRAM/SRAM technologies. However, their efficiency is often hindered by the need to shift the targeted data to access ports for read and write operations. Suitable mapping approaches are therefore essential to unleash their potential. In this work, we explore the mapping of the popular tree-based document ranking algorithm, Quickscorer, onto Skyrmion-based racetrack memories (SK-RTMs). Our approach leverages a Logic-in-Memory (LiM) accelerator, specifically designed to execute simple logic operations directly within SK-RTMs, enabling an efficient mapping of Quickscorer by exploiting its bitvector representation and inter-leaved traversal scheme of tree structures through bitwise logical operations. We present several mapping strategies, including one based on a quadratic assignment problem (QAP) optimization algorithm for optimal data placement of Quickscorer onto the racetracks. Our results demonstrate a significant reduction in read and write operations and, in certain cases, a decrease in the time spent shifting data during Quickscorer inference
Morphodynamics of sandy anthropogenic shores:Beach-dune systems affected by human action
Get PDFThis thesis investigates how human activities and natural dynamics jointly shape the long-term development of Sandy Anthropogenic Shores (SAS)—coastal landscapes created by large-scale sand nourishments, such as the Sand Motor and Hondsbossche Dunes in The Netherlands. These engineered interventions aim to improve flood safety, promote dune formation, and enable ecological and recreational use. However, how natural dynamics and human activities interact to influence the morphological development of SAS remains insufficiently understood.To address this, the thesis extends and applies the DuBeVeg model, a cellular automata framework for simulating decadal beach-dune evolution. DuBeVeg was enhanced to better represent aeolian sand transport, sediment availability, and surface armouring, which are processes especially relevant for SAS. These improvements made it possible to simulate the formation and spatial variability of embryonic dunes, and to explore how these patterns develop over time in a transient SAS such as the Sand Motor. The simulations also showed how initial design choices influence long-term dune development. For example, the armour layer that develops when the nourishment material is less well-sorted and coarser than native beach sand, led to the emergence of more scattered and isolated dunes compared to a nourishment with native beach sand.A key contribution of this thesis is the integration of recreational impacts into the model. By including the effects of car and foot traffic on vegetation, it was possible to explore how human use affects dune morphology and sand distribution. The results suggest trade-offs between recreation and ecological diversity, and point to management strategies such as zoning or limiting access.The extended DuBeVeg model serves as a tool for assessing design and management scenarios. It offers insights into how SAS can be planned to balance flood protection, ecological value, and recreation, supporting the development of resilient coastal landscapes through nature-based solutions
Small Tamagawa numbers of elliptic curves with isogenies or torsion
Get PDFIn this article with study Tamagawa numbers of elliptic curves defined over that have isogenies or torsion points. More precisely, our aim is either to bound the set of primes primes that can divide their Tamagawa numbers or, when such a bound is not possible, to find infinite subfamilies whose Tamagawa numbers are as small as possible. Finally, we also investigate Tamagawa numbers of specializations of elliptic surfaces
Operators’ Experiences with Intelligent Compaction Systems in Road Pavement: A Technological Mediation Approach
Get PDFThis study delves into the influence of intelligent compaction (IC) systems on the perceptions and actions of roller operators in road pavement practices. These operators occasionally tend to ignore these IC systems or even turn them off while performing their tasks. A major question is why the operators don’t always use IC systems. By using the technological mediation approach, operators’ reasons for ignoring or even turning IC systems off in road pavement practice are explored. In the technological mediation approach, users and technologies co-shape each other. Based on semi-structured interviews with roller operators, experiences with these systems are investigated. Physical, cognitive, and contextual mediation through IC systems is related to behavior-changing strategies encompassing coercive and persuasive interventions, as well as decisive designs. These interventions are now experienced as conflicting with the individual autonomy and responsibility of the operators for the quality of work. Because IC systems amplify certain facets of reality while reducing others, roller operators must ensure that the output of an IC system is judged in the light of the specific project context. Given their “thrownness” in such a specific context, operators’ experience and tacit knowledge remain important for taking action