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Experimental Investigation on Foaming Factors and Foaming Characteristics of Oil/Refrigerant Mixtures
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Transition of buoyancy-driven flow from an axisymmetric to non-axisymmetric vortex inside an evaporating sessile droplet
No full textThe internal flow within an evaporating sessile droplet has intriguing fluid mechanics important to various microfluidics applications. In the present study, a phenomenon is observed through numerical methods wherein the buoyancy-driven flow structure inside a droplet on a non-wetting substrate transitions from an axisymmetric toroidal vortex flow to a non-axisymmetric single vortex flow with increase in the substrate temperature. As the axisymmetric nature of the droplet flow field and evaporation characteristics are broken, the internal velocity accelerates significantly. The transition, which is attributed to a flow instability inside the droplet, is more prone to occur as the droplet volume or the contact angle increases. The onset of the flow transition is analysed as the amplification of a small perturbation, thereby establishing a correlation between the flow instability and the Rayleigh number (Ra). Specifically, when Ra exceeds some critical value, the onset of the flow transition is observed, which explains the effects of substrate temperature and droplet volume on the internal flow. Next, the influence of the droplet contact angle on the critical Ra was investigated, and the underlying reasons were analysed. Finally, we discuss the heat transfer efficiency within the droplet and analyse why the internal flow tends to transition to a non-axisymmetric flow pattern from an energy minimization perspective
Identifying invasive species sightings from GeoAI-validated social media posts
Get PDFThe spread of invasive species requires scalable monitoring techniques to help guide management and conservation strategies. Here, we explore the potential of GeoAI for the rapid validation of invasive species sightings through social media data. We utilized the Flickr API to retrieve 23,000 images from posts that contained the names of 72 invasive species across various taxonomic categories within the contiguous USA. Then using BioCLIP, a computer vision model capable of identifying over 450,000 species, we assessed whether these posts genuinely contained the species that the user tagged. Results varied, with some species like the European Starling showing high match rates, while others like the Alewife had limited matches. This highlights both the strengths and limitations of using GeoAI for ecological monitoring. We also discuss the potential for passive monitoring by analyzing images from specific areas without relying on user-provided species tags. Our findings emphasize the need for scalable, automated solutions to complement manual validation efforts. The study provides reproducible code and instructions via the I-GUIDES platform, enabling ecologists and land managers to implement these tools for real-time monitoring and managing of invasive species. By fostering citizen science initiatives, we aim to enhance the practical application of these methods, ultimately contributing to more effective conservation strategies
Data-Intensive Convergence Science for Analyzing Place-Based Spatial Accessibility
Get PDFPlace-based spatial accessibility is a critical tool for measuring the health, resilience, and sustainability of communities. Accessibility methods are employed by a wide range of fields to measure access to food, healthcare, infrastructure and other critical needs. While measures of access are relatively simple, they attempt to capture the complexities of human mobility and spatial decision-making to assess how well populations are served by the infrastructure, resources, and services at their disposal. This paper describes four key areas where data-intensive convergence science can revolutionize our understanding of place-based spatial accessibility by addressing issues of scale, spatial impedance, diversity, and accessibility. By tackling these key issues, we can create measures of access that are more detailed, accurate, inclusive, and approachable, making place-based spatial accessibility a better diagnostic tool as we work towards more sustainable places
