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Asymmetrical morphological evolution and energy conversion of droplets impacting on the moving film
No full textDroplet impacting on the film has been an important research topic, which is relevant to many important industries and is of high utilization value. The droplet impacting process shows excellent mass and heat transfer capability, whereas the liquid film is often in a flowing state, the morphological deformation and energy conversion of successive droplets impacting a moving liquid film were investigated. A threedimensional volume of fluid model coupled with level-set function was established to investigate the single and successive droplet impact on the moving film. The asymmetry dynamic and energy dissipation and in the morphological evolution of the simultaneous single and successive droplet impacting processes under different droplet Weber numbers Wed and film Reynolds numbers Ref were thoroughly investigated. With smaller Wed and larger Ref , the liquid sheet downstream of the crown is more suppressed and the asymmetry of the crown is more significant. When Ref is constant, the dimensionless radius of the crown is related to the Wed 0:2 and also to the power of dimensionless time, with the exponents differing between the upstream and downstream. The relationship of energy dissipation with dimensionless number was discussed, in which the kinetic energy Ek reduction accounts for a major part of the dissipation even though the surface energy Es increases due to the formation of the crown. Additionally, the upstream liquid sheets merging of the inner and outer crowns due to successive droplets continuous impacting on the moving film were also observed. With larger Ref and lower impingement frequency, the merging of the upstream liquid sheets is earlier
Heat exchanger design and performance evaluation for a high-temperature heat pump system under different two-phase correlations:4E analysis
No full textSupplying district heat and assisting the integration of renewable electricity, high-temperature heat pump technology is foreseen to play an essential role in renewable energy-powered thermal energy storage systems. However, existing studies on high-temperature heat pump performance prediction are usually based on utilizing specific heat transfer correlations of heat exchangers. It is difficult to guide the selection and combination of the two-phase correlations in the heat exchanger design and system performance assessment of the high-temperature heat pump. In the present study, we aim to focus on the impact of different two-phase correlations, and a comparative study is conducted among 8 correlations (4 flow condensation ones and 4 flow boiling ones) adopted for component design and system performance prediction. The results show that for designed condensers or evaporators, the dimensions, costs, and carbon emissions are significantly affected by different two-phase correlations. Among 16 pairs of two-phase correlations, little fluctuation of the system performance is observed at the design heat source temperature 80 °C. While at off-design heat source temperatures of 85, 90 or 95 °C, the energetic and exergetic performance parameters are significantly affected with high relative differences (9.88% of heating capacity, 3.27% of coefficient of performance, and 6.76% of exergy efficiency). Also, the system's economic and environmental performance indexes are influenced to some extent, with visible relative uncertainties (1.91% of the heating cost, 4.44% of the payback time, and 6.38% of the carbon emission). This research will help to promote the selection and utilization of two-phase correlations for the plate heat exchanger design and system assessment in larger renewable energy-powered high-temperature heat pump applications.</p
Performance analysis of centrifugal compressors in supercritical CO₂ Brayton cycles considering non-equilibrium condensation
No full textEnergy storage technologies play a critical role in balancing energy supply and demand, as well as facilitating large-scale integration of renewable energy sources. The supercritical carbon dioxide (sCO₂) Brayton cycle, known for its high efficiency and compact design, is widely regarded as an ideal solution for large-scale energy storage. However, the dramatic variation in sCO₂ thermodynamic properties near the critical point can induce condensation within compressors, adversely affecting system performance and stability. To address this challenge, this paper presents a novel condensation flow model that integrates the entropy transport equation with real gas thermodynamics, enabling precise prediction of condensation behavior and its impact on compressor performance. The results show that when the inlet temperature decreases from 320 K to 310 K, condensation is significantly intensified, with phase-change entropy generation increasing by 9.16 times and heat transfer entropy generation increasing by 47.2 %, resulting in greater exergy destruction and reduced efficiency. Compared to conventional dry gas models, the proposed model provides a more accurate assessment of compressor efficiency, avoiding overestimation errors of up to 11.6 %. This theoretical tool offers the scientific community a new approach for in-depth analysis of condensation phenomena within compressors, supporting the optimization of sCO₂ energy storage system design, enhancing system stability and efficiency, and addressing engineering challenges such as blade corrosion.</p
Domestic Dusters:Exploring threat in vulnerable communities. An investigation of isolation and dislocation through embroidery of a duster.
Get PDFThis paper presents work from my award-winning collaborative research project Domestic Dusters, which invites women from across the globe to embroider their domestic experiences onto yellow dusters. Established in 2015, the 800+ ever growing collection is exhibited internationally in arts, community and academic contexts (fig. 1) alongside publications that explore the duster as a research tool through drawing with thread (Marr 2019), storytelling through craft as a feminist practice (Marr 2021), domesticated experiences of academia (Marr, 2023), and stitch-drawing into a duster as an autoethnographic practice for personal wellbeing (2025). Collectively, these dusters display perspectives on home and its often-gendered expectations, capturing experiences of both privilege and hardship as embroidered words and images, with humour, sadness, anger, frustration and joy.Dusters were selected as a metaphor for domesticity because of their cultural associations with invisible gendered labour (Kirkham 1996), whilst the use of hand embroidery women’s legacy of working with cloth (Barber, 1996), its association with oppression (Parker 1984) and more recent empowerment (Greer 2014). Participants are invited via an open call or through funded initiatives with community partners, addressing domestic issues from everyday discrimination through to unpaid care, gender-based violence, and asylum seeking. In each instance, the gendered inequalities of domestic labour that serve to threaten every aspect of women’s lives are at the fore, positioning this mundane domestic object to give women a voice where they are silenced, ignored and unheard.In line with the conference theme, it shares dusters embroidered by women whose domestic circumstances are under threat due to two contrasting situations, capturing the lived experience of enforced home confinement by unpaid carers, and dislocation from their own homes by asylum seekers living in temporary accommodation. Produced through community partnerships with We Care who campaign for the rights of unpaid carers, and Makani who work for the empowerment of refugee women, this research ‘strives for social justice’ (Adams, Holman Jones and Ellis, 2015, p.2) and offers insights into domesticity under siege through the lens of a humble yellow duster
Hate Crime Perpetrators: New Perspectives from Theory, Research and Practice , Volume I:Understanding Offender Profiles and Motivations
No full textThis two-volume edited collection showcases the work of leading scholars researching hate crime perpetration. It explores current research into hate crime perpetration, develops theoretical perspectives, and provides scholarly analysis of legal frameworks, policy responses and criminal justice practice. It seeks to understand how hate and intolerance manifest and are perpetrated. This Volume (I) focuses on offender profiles and motivation while Volume II examines developing responses to hate in online and offline settings. Together they highlight links between different forms and arenas of hate crime offending and provide new perspectives on the nature of contemporary hate and intolerance, how it can be understood, and how it might be effectively tackled.This two-volume collection contends that ‘difference’ in all its forms can be targeted by vitriol and abuse across and beyond the recognised ‘five strands’ of hate crime law and policy in England and Wales (racist, religiously motivated, homophobic, transphobic and disablist) alongside broader behaviours that underpin intolerance (such as scapegoating, stereotyping and microaggressions). These volumes bring together a range of perspectives to provide the readers – be they students, academics, policy makers, practitioners or the general public – with a comprehensive understanding of this topic
Association between redox dysregulation and vulnerability to cognitive deficits induced by maternal immune activation
Get PDFExposure to maternal immune activation (MIA) in utero is a major risk factor for neurodevelopmental disorders, including schizophrenia. However, a proportion of individuals are resilient to developing schizophrenia following exposure to MIA, which has also been reported in animal models of MIA. The molecular mechanisms leading to resilient and vulnerable behavioural phenotypes remain poorly understood, and we currently lack reliable blood biomarkers that predict resilience or vulnerability. Redox dysregulation, caused by an imbalance between oxidative stress and antioxidant defence mechanisms, has recently been predicted to be central to the pathogenesis of schizophrenia. Here, we use a poly(I:C)-induced MIA model of schizophrenia to investigate mechanisms underlying cognitive dysfunction and redox dysregulation in resilient and vulnerable individuals. We show that activity of the antioxidant enzyme superoxide dismutase (SOD) was reduced in the plasma of poly(I:C) offspring with a cognitive deficit, in contrast to individuals with typical cognition during both adolescence and adulthood. However, SOD activity in the hippocampus was not significantly different between vulnerable and resilient offspring. In addition, the lipid peroxidation marker malondialdehyde (MDA) and the pro-inflammatory cytokine IL-6 were not differentially expressed within the hippocampus or plasma of vulnerable poly(I:C) offspring. Our results suggest that reduced plasma SOD activity may be a potential blood biomarker to identify resilience or vulnerability to MIA-induced cognitive deficits. Further research is necessary to determine if reduced antioxidant capacity is present in plasma prior to symptom presentation and to understand if this predicts redox dysregulation in the brain
Origins of compositional diversity in natural zeolites within the Antrim Lava Group, Northern Ireland, UK
No full textThe Antrim Lava Group comprises voluminous alkaline basalts, less extensive tholeiitic basalts, and inter-flow sediments formed in the Palaeocene between 63.2 and 60.0 Ma during early rifting of the North Atlantic. Zeolites and associated minerals crystallized within vesicles during post-eruptive hydrothermal overprinting as the lava pile of >80 flows accumulated. Studies in the mid-20th century established geographical patterns in zeolite species distributions which reflect host rock chemistry (alkaline vs. tholeiitic) and coastal vs. inland exposures of the lava pile. Zeolites crystallized from relatively high-salinity hydrothermal fluids, such as phillipsite-Na, gmelinite-Na and gobbinsite, appear to be spatially associated with coastal outcrops of the Antrim Lava Group. Unusual Mg-rich varieties of chabazite and heulandite are geographically restricted to a coastal location on Islandmagee.Data presented here as bivariate and ternary compositional diagrams, from EMPA obtained in PhD research in the 1980s and more recent EMPA and SEM-EDS analyses, illustrates a wide heterogeneity in alkaline element chemistry and Si/Al ratios in Antrim zeolites. We explore the extent to which this diversity may be due to ionic exchange with modern seawater in specimens from coastal locations. Inland and coastal localities of Antrim zeolite specimens are distinguished on previously published discrimination diagrams utilizing graphs of Si/Al vs. (Na+K)/Ca in phillipsite and chabazite associated with freshwater and seawater-influenced environments in Antarctica. A marine influence is also clearly evident in erionite and gmelinite given their wide compositional ranges extending to high ratios of Si/Al and (Na+K)/Ca in specimens from the same localities where phillipsite and chabazite show high ratios. Individual crystals commonly show zonation from Ca-dominant cores to Na-dominant rims, for example changing from garronite in the core to gobbinsite in the rim. Chabazite from Rathlin Island and erionite and cowlesite from the north coast location of Dunseverick have exceptionally high Na contents. We infer that seawater interaction is more rapid and extensive with fibrous zeolites such as erionite than with species that form blocky crystals.<br/
FEPSAC position statement on safeguarding athletes in sport
Get PDFThrough the publication of this position statement, FEPSAC aims to continue with its commitment to quality and safe sport experiences through the promotion of safeguarding in sport, a responsibility collectively shared by both group and individual members of the organisation. In this paper, we provide a brief overview of the academic research on interpersonal violence and safeguarding in sport in a European context, focusing on safeguarding athletes. The position statement further includes recommendations and practical guidelines that will equip readers with knowledge and processes for recognising and responding to IV in sport. Through enhancing safeguarding literacy among FEPSAC members, we aim to inspire and empower both neophyte and more experienced practitioners in sport and exercise psychology toward fostering safer sporting relationships, spaces and practices
Feasibility of identifying two-phase flow quality by Shadowgraphy
Get PDFTwo-phase process conditions are applied across numerous applications due to their effectiveness in energy transfer, production and storage. Two-phase is important for heat transfer in cryogenics, dense expansion in power production, and storage in liquid-cooled batteries. Shadowgraphy capture offers a non-invasive technique that allows a real-time measurement of characteristics, such as steam wetness. If phase conditions could be determined during operation, optimum fluid wetness could be maintained, resulting in a more efficient energy system. This paper employs the optical technique of shadowgraphy, utilising a Photron SA4 camera for image capture, coupled to the developed algorithm in the imaging software tool, ImageJ, to develop a method for the process of estimating steam quality and void fraction captured in a horizontal orientation. Void fraction was achieved using chordal widths of 20 pixels, both horizontal and vertical across a 30 mm tubular sight glass, estimating the chordal liquid content with a time-averaged quantitative comparison, using processed greyscale images. Techniques for further optimisation of accuracy are detailed with respect to image visulisation, image processing, and importantly, results from a gravitational condensate trap are presented for validation. Results for a flow velocity of 50 m/s and at a pressure of 1.3 bar were calculated as near 0.98 gaseous content. This work demonstrates the feasibility of shadowgraphy for wet steam process conditions, and offers a new measurement technique for estimating the two-phase fraction in flows of high vapour content, thus complementing the advancement in parallel techniques such as vortex and orifice flow measurements