58622 research outputs found
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A spatial agent-based approach to simulating the ride-hailing system and its environmental impacts
Get PDFRide-hailing services could potentially optimize vehicle use and reduce emissions. To investigate the diffusion of ride-hailing services and its impacts at the individual level, we proposed a spatial agent-based model, which integrated the supply-demand dynamics, to simulate the behaviors of the service provider, drivers, and users in Shenzhen, China, from 2023 to 2038 in various future scenarios. The results of the baseline scenario (assuming the market would evolve as before from 2023 to 2038) show a 36 % increase in annual ride-hailing usage, a 24.63 % decrease in the average ride-hailing price, and a 73.16 % increase in drivers' compensation. Carbon emissions reduces by 33.13 % (given that ride-hailing services replace existing combined transportation modes). The what-if scenarios show that price and compensation affect the ride-hailing system in the early stages and further its carbon emission reduction potential. The results would be useful for policy making and optimization of a ride-haling system.<br/
Apprenticeship by another name? Media discourses and the vocational turn in Nigerian higher education
Get PDFPurposeAs the UK marks a decade since the introduction of degree apprenticeships, sparking international interest in work-integrated models of Higher Education (HE), this paper shifts focus to Nigeria, a former British colony where global pressures, national priorities, and inherited academic traditions converge. Situated within a postcolonial context, Nigeria continues to grapple with British-influenced educational ideals while increasingly seeking to transform its HE system in response to youth unemployment and global competitiveness.Design/methodology/approachThis study investigates how HE is constructed in public discourse through a media analysis of three Nigerian news media, Punch, Daily Trust, and Daily Post, between 2021 and 2022, following the introduction of the Core Curriculum and Minimum Academic Standards (CCMAS) policy. The study combines thematic and discourse-historical approaches to analyse dominant media narratives and identify which voices influence public debates. Bourdieu's capital and institutional habitus logic guide the interpretation of how power and ideology shape media representations of HE.FindingsThe analysis identifies two main framings: HE as a pipeline for producing future workers and as a site increasingly focused on vocational, apprenticeship, and entrepreneurial training. Also, there is a hegemonic construction of HE in Nigeria, where academics and the government have prominent voices in the media. The findings visibilised the need for more inclusive conversations about HE's role, involving a wider range of stakeholders.Originality/valueThis paper adds a Southern perspective to international debates on HE reform, showing how apprenticeship-like models, though not formally institutionalised, are discursively promoted through media narratives advocating for employability, entrepreneurship, and work-readiness in Nigerian HE
Passively pitching blades for tidal turbines:Experimental Demonstration
Get PDFTidal turbines operate in adverse flow environments, resulting from high turbulence, waves, and shear, which can lead to large unsteady forces acting on the blades and thus to structural fatigue. To mitigate these unsteady loads, and to cap the maximum power when the flow speed is above rated, turbines use active pitch control systems that adapt the blade pitch to the flow condition. Active pitch control systems require additional gearboxes and motors that increase capital and operational costs, require additional maintenance and may decrease system reliability. To address these challenges, Viola et al. (2022) introduced a novel passive pitching blade concept. The blades passively adjust their pitch in response to the oncoming flow conditions. One way of achieving this is to mount each blade onto a torsional spring. Liu et al. (2024) showed numerically that passive pitching foils can mitigate lift fluctuations by at least two-thirds. Otomo et al. (2024) developed a mathematical framework for optimising the pivot point location to maximise unsteady load mitigation. Gambuzza et al. (2025) demonstrated experimentally that passively pitching blades can be used to keep the power constant above rated conditions while reducing thrust loads.Most previous studies have focused on the effect of varying the tip speed ratio and the freestream speed on power and thrust loads. Instead, in the present work, we study the effect of spring preload on the system performance by conducting experiments on a 1.39-metre-diameter turbine equipped with three independently passively pitching blades. Experiments were conducted at the University of Edinburgh’s Flowave Ocean Energy Research Facility. Results indicate that a turbine equipped with passively pitching blades achieves design-point performance similar to that of a turbine with fixed pitch blades. It is shown that there is an optimum spring preload that enables the turbine to operate at rated power despite a change in tip speed ratio, while reducing both mean and fluctuating thrust by nearly 20% and 30%, respectively. By changing the spring preload, the tip speed ratio at which the power is matched can be tuned - lower preload gives matched performance at a lower tip speed ratio. Passive pitch blades are also shown to have higher hydrodynamic efficiency at the design point(78% as opposed to 55% for fixed pitch blades)
Expert Memories:The Professional Construction of the Past and the Mnemonic Making of Occupations
Get PDFThis article introduces the special issue on occupations and memory in organizations. To foster increasing collaboration from scholars from both fields, we offer a general argument connecting memory and occupations on two levels. At the societal level, we show how memory experts, such as historians, archivists, and museologists, have played a fundamental role in the development of modernity and the emergence of our contemporary historical consciousness. At the occupational level, we argue that occupations are transgenerational communities maintained through various practices and technologies of memory whose legitimacy and professional status increasingly depend on their ability to cultivate both practical and historical memory. We further explore three related topics covered by the papers from this special issue: expert and memory work, occupational and mnemonic communities, and professional and mnemonic projects. At the end, we identify three promising themes for future research: the negotiation of boundaries and resources among communities; the interaction between technology, expertise, and memory; and the occupational ethics and responsibility towards past actions and memories.</p
Dataset for the dynamic and static loading of fibrous plaster ceilings, featuring in-situ monitoring, large and small scale samples
No full textThe dataset contains the predominantly excel spreadsheets for the dynamic and static loading of fibrous plaster ceilings. The dataset cover the in-situ monitoring of accelerations in a historic partner theatre, termed Theatre 'A' and the monitoring of accelerations, displacement and strain of laboratory large scale fibrous plaster ceiling panels, small scale sample tests include flexural, compressive and tensile tests. Tensile tests featured newly manufactured and historic material, with the newly manufactured specimens featuring both traditional materials and modern alternative repair material options. Tensile tests on wads were conducted at both the Diamond Light Source and in the structures laboratory. The compressive tests feature historic material
Relightable Detailed Human Reconstruction from Sparse Flashlight Images
Get PDFWe present a lightweight system for reconstructing human geometry and appearance from sparse flashlight images. Our system produces detailed geometry including garment wrinkles and surface reflectance, which are exportable for direct rendering and relighting in traditional graphics pipelines. By capturing multi-view flashlight images using a consumer camera equipped with an co-located LED (e.g., a cell phone), we obtain view-specific shading cues that aid in the determination of surface orientation and help disambiguate between shading and material. To enable the reconstruction of geometry and appearance from sparse-view flashlight images, we integrate a pre-trained model into a differentiable physics-based rendering framework. As the learned image features from synthetic data cannot accurately reflect the shading features on real images, which is crucial for the high-quality reconstruction of geometry details and appearance, we propose to jointly optimize the image feature extractor with two MLPs for SDF and BRDF prediction using the differentiable physics-based rendering. Compared with existing methods for relightable human reconstruction, our system is able to produce high-fidelity 3D human models with more accurate geometry and appearance under the same condition. Our code and data are available at http://github.com/Jarvisss/Relightable_human_recon.</p
Enhanced piezoelectric properties of additively manufactured BCZT with an oriented ceramic lamellar structure formed via vat photopolymerization
Get PDFAdvances in additive manufacturing have enabled the creation of piezoceramic materials with complex architectures. However, the lack of a clear structural design strategy limits their performance and application in high-performance piezoelectric transducer devices. This work outlines the additive manufacture of a novel sandwich architecture based on a porous (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 (BCZT) layer containing oriented ceramic lamellae. The d33 charge coefficients and g33 voltage coefficients of the optimized porous ceramic were 1.16 times and 2.11 times higher than those of the dense counterparts respectively. After electroding the aligned lamellar ceramic with an indium tine oxide film a piezoelectric sensor was obtained which, when subject to a pressure of 7.5 MPa, produced a open circuit voltage of 173 V. This paper provides a new structural design strategy to effectively improve the performance of piezoelectric ceramics, and provides new opportunites for the design and production of additive manufactured piezoelectric sensors and energy harvesting devices.</p
Rotordynamics of a Single-Stage Brush Seal in Isolation:The Effects of Variable Stiffness and Back Plate Geometry
Get PDFBrush seals control leakage around rotating components from areas of high to low pressure inside turbomachinery. They are known to contribute to the overall stability of gas turbines, therefore their dynamic behavior is of particular importance to engine designers. Despite this, limited research exists in the literature on the rotordynamic behavior of brush seals. This paper aims to experimentally characterize the leakage and rotordynamic performance of two seals with different bristle diameters tested with both conventional and pressure-relieved back plates with a slight interference. A dynamic test facility was utilized to study the dynamic characteristics of an isolated seal with changes in excitation frequency, rotational speed, and pressure drop. Seal leakage increased with bristle diameter and with the use of the pressure-relieved back plate but reduced with increasing rotational speed for all tests. The direct dynamic coefficients were shown to increase with pressure difference. The back plate geometry influenced the change in stiffness coefficient with rotational speed. The larger bristle diameter resulted in a stiffer seal, however, the damping coefficient reduced with the reduction in packing density. The insight provided by these results will help inform engine manufacturers on the suitability of implementing brush seals in future gas turbine designs
Researching organized crime:A novel approach combining inductive and storyline paradigms
Get PDFThis article examines the methodological process employed in two recent research projects about mafias and organized crime groups (OCGs) and considers the self-reflexion that took place as part of the research process. Whereas most contemporary studies that focus on mafias and OCGs use theoretically informed approaches, which follow a hypothetical-deductive model, here a novel approach of combining an inductive model based on a Grounded Theory Method (GTM) with a storyline approach is presented. This results in perhaps a more thorough understanding of mafias and OCGs and produces a clear knowledge and evidence-based account of these realities that could be useful for practitioners. This article presents an innovative research design used in the general study of organized crime, the combination of a GTM with a storyline approach. Firstly, it explains the rationale and the steps involved in this combination. Secondly, its application in two specific research projects on organized crime is explained, empirically and theoretically. Thirdly, a critical reflection on the suitability of these two paradigms for the study of contemporary social phenomena is presented. Lastly, the conclusions suggest that while a GTM may be considered to lack positivist rigour, the contribution it makes to our understanding of mafias and OCGs must not be underestimated, in particular when combined with the storyline approach, which anchors evidence to theory
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