Gustavus Adolphus College Collections
Not a member yet
92910 research outputs found
Sort by
The impact of dilution air strategy on n-heptane turbulent swirl spray flames
No full textThis paper investigates the impact of dilution air addition on the stability and flame structure of n-heptane turbulent swirl spray flames. Particle Image Velocimetry (PIV) was used to study the flow fields with and without dilution air. OH Planar Laser Induced Fluorescence (OH-PLIF) measurements were utilized to assess the impact of dilution air addition on flame structure, local extinction, and lift-off. Experimental results were collected at different flow conditions including quenching point (global blow-off), near blow-off, and stable conditions. 1D non-premixed laminar counter-flow flame simulations were also conducted to gain preliminary understanding of the flame structure behaviour and temperature when adding more air with hot products. The numerical results showed that adding 10 % more air on the oxidiser side increased the peak values of the temperature, heat release rate (HRR) and OH mole fraction, with the maximum flame temperature rising by approximately 3.9 %. The flame’s stability limit increased when adding dilution air, and a 2 % addition made the flame persist longer. The flame restabilized with the addition of 5 % dilution air at the blow-off co-flow conditions of the non-diluted flames. OH* chemiluminescence results showed that the addition of dilution air up to 10 % of the co-flow increased the heat release rate by as much as 247 %, indicating a strong enhancement in flame intensity and reaction zone activity. The addition of dilution showed the droplets to spread more widely into the inner recirculation zone (IRZ). PIV showed a clear displacement of the vortex inwards and upwards when adding dilution air, with increased turbulence intensity aligned with shear layers. Without dilution air, the OH flame sheet appeared continuous, while with dilution air, it appeared to be wrinkled, cloud-shaped, and distributed. Statistical analysis of the OH-PLIF results showed that adding 5 % dilution air increased local extinction events by up to 7.5 %, primarily due to the intense aerodynamic strain imposed on the flame front under highly turbulent conditions. OH-PLIF results showed that the addition of dilution air increases the relative OH intensity in the outer flame branch (OFB) at the same horizontal plane downstream. The novel findings on extended operation condition effect by adding dilution air provide the first evidence of enhanced flame stabilization towards lean combustion strategy
From symbiosis to scarcity: evaluating disruption associated with decarbonisation to circular waste materials between the UK cement and steel sectors
No full textThe UK cement and steel industries are decarbonising rapidly to meet net-zero targets. This study explores the unintended consequences of these efforts, particularly the potential disruption of industrial symbiosis between sectors. Cement production in the UK increasingly relies on ground granulated blast furnace slag (GGBS), a low carbon supplementary cementitious material (SCM). However, the shift from primary to secondary steelmaking threatens domestic GGBS supply. This research uses material flow analysis, life cycle assessment, and economic modelling to evaluate future GGBS availability, carbon intensities, and supply chain vulnerabilities. Findings indicate that although the steel sector is expected to reduce its environmental impact, this will cause the cement sector to face a potential shortfall in domestic SCMs, increasing reliance on imports through cross-sector decoupling and stagnation of decarbonisation. Addressing these challenges is vital to ensure a sustainable cross-sector supply chain and support future UK and global infrastructure resilience
Radiotherapy for oesophageal cancer in the United Kingdom: patterns of practice & quality indicators
No full textAims
There is limited guidance relating to the provision of radiotherapy for patients with oesophageal cancer. Given this, we sought to assess variation in patterns of care in the UK and to devise quality improvement metrics to support future treatment standardisation.
Materials and Methods
We undertook a cross-sectional survey using a bespoke online survey to explore geographical variation in radiotherapy use for oesophageal cancer across the United Kingdom (UK) National Health Service (NHS). These data were combined with an observational registry analysis using the National Disease Registration Service Radiotherapy Dataset to explore temporal variation in radiotherapy utilization from January 2020 – June 2024.
Results
Survey responses were received from 75% (n = 45/60) of UK centres. These demonstrate considerable variation in the interpretation of radiotherapy indications, particularly in the non-curative setting, as well as in radiotherapy technique; with, for instance, one third (n = 15/45) of centres reporting that they do not use motion management strategies for lower third or junctional tumours. Induction chemotherapy use differs between centres and by concurrent regimen, with 93–96% (n = 42–43/45) of centres using induction treatment prior to concurrent platinum/fluoropyrimidine and 56–62% (n = 25–28/45) using it prior to concurrent platinum/taxane. Post-treatment surveillance and follow-up measures also differed with little evidence for more intensive surveillance in patients fit for salvage resection. Most centres reported the use of intensity modulated or volumetric arc therapy (IMRT/VMAT) for radical plans, which was supported by NDRS data demonstrating that the median proportion of patients in each centre treated using IMRT/VMAT increased from 60% (range 14.3–100%) in January-June 2020 to 91.7% (range 16.7–100%) in January-June 2024.
Conclusions
There is substantial variation in the radiotherapy-based care of patients with oesophageal cancer in the UK. Formal national guidance is required to build on the quality metrics outlined here
Cueing autobiographical memory in young and older adults: an exploration of the effect of cue type on retrieval rates and memory characteristics
No full textCurrent theories of autobiographical memory (AM) emphasise the involvement of several non-memory auxiliary processes, such as executive function and mental imagery. However, the contribution of these processes to AM retrieval under different circumstances remains poorly understood, particularly in the context of ageing. The extent to which different AM tasks rely on auxiliary processing could explain variability in age-related AM deficits across different contexts. The current study explores the effect of cues varying in format (words, questions, sentences, photos, and videos) and content (e.g., event cues, evaluative cues, imagery cues) on AM retrieval rates in young and older adults. In Experiment 1, young and older adults (n = 101) retrieved AMs in response to a set of 208 cues; dependent variables were the proportion of cues that produced a memory, and ratings of the characteristics of the retrieved memories. Results showed that retrieval rates were influenced by both cue format and cue content, with cues that most closely mapped the task requirements producing the largest proportion of memories, regardless of other cue features (e.g., detail, imagery). Study 2 collected data from a separate group of 106 adults concerning their interpretation of the same cues, and analysed the responses in relation to the data from Experiment 1. Both retrieval rates and memory characteristics were related to features of the cues, such as specificity, theme, and emotional content. Data suggested that less easily accessed memories tended to be more autobiographically important. All materials and data - including 2500 brief descriptions of participants' autobiographical memories - are freely available for further exploration
Application of continuous glucose monitoring and automated insulin delivery technologies for pregnant women with type 1, type 2, or gestational diabetes: an international consensus statement
No full textInsulin resistance increases after the first trimester of pregnancy, leading to glycaemic challenges for women with pregestational type 1 diabetes or type 2 diabetes. Additionally, insulin resistance can promote hyperglycaemia in pregnant women without type 1 diabetes or type 2 diabetes, who develop gestational diabetes. Although most (>95%) women with diabetes deliver healthy babies, maternal dysglycaemia can have consequences for the mother and child, including prenatal, perinatal, immediate, and long-term postnatal complications. Diabetes technologies, such as continuous glucose monitoring (CGM) and automated insulin delivery (AID) systems can aid in optimising glycaemia outside of pregnancy. These novel technologies have not been extensively tested in large randomised controlled trials before and during pregnancy. However, compelling data report the benefits of CGM in type 1 diabetes, and increasing data report on AID systems in pregnancies complicated by type 1 diabetes. Appropriate CGM glucose thresholds for the diagnosis of gestational diabetes and the recommended time in range treatment targets for the routine management of gestational diabetes and type 2 diabetes still need to be determined. The recommendations in this Consensus Statement emphasise the value of CGM during preconception and pregnancy for women with pregestational type 1 diabetes in reducing pregnancy complications. Recommendations also include the use of AID systems in women with pregestational type 1 diabetes to improve glycaemic management during preconception, during pregnancy and delivery, and in the postpartum period. This Consensus Statement has been endorsed by 24 societies and groups
Reducing the exceptional affordability of hand-rolling tobacco using tax escalators: a health and economic impact modelling study for England
No full textBackground
Hand-rolling tobacco (HRT) remains more affordable than factory-made (FM) cigarettes in the UK, which could undermine the health benefits of tobacco tax increases. This study modelled health and economic impacts of raising HRT duty annually to reduce this affordability gap.
Methods
We used the Sheffield Tobacco and Alcohol Policy Model V.2.5.0, an individual-level microsimulation, to project tobacco consumption, spending and health outcomes for adults in England aged 18–89 from 2024 to 2030. Four duty policies were compared against a business-as-usual scenario of duty rising 2% above the Retail Price Index (RPI) annually: Policy A increased duty by RPI+12% in 2024 only (the UK Government’s October 2023 policy); Policy B applied RPI+10% annually to align with FM duty by 2030; Policy C applied RPI+12% annually; and Policy D applied RPI+18% annually to equalise average HRT and FM prices by 2030.
Results Policy
A was estimated to prevent 1770 deaths, add 36 947 life years and save the National Health Service £12 million, with greater gains in deprived areas. Policies B–D achieved larger health benefits and reduced inequalities, but increased spending by people who smoke. Policy D generated £3.19 billion additional tax revenue and reduced tobacco industry revenue by £400 million by 2030. Revenue effects depended on assumptions about how higher HRT prices affected FM consumption.
Conclusions
Sustained duty increases on the least expensive tobacco products could deliver substantial public health gains and reduce health inequalities. Such measures should coincide with strong enforcement against illicit tobacco and comprehensive smoking cessation support
Corrigendum to “Catalytic dissociation of a water molecule on the (1 1 1) surfaces of Pt0₀.₅Ni₀.₅ bimetal: Density functional theory (DFT) study”. [Appl. Surf. Sci. 602 (2022) 154238]
No full textWritten input and the encoding of L2 phonological contrasts:L1 Arabic learners of L2 English
No full textMany adults learn languages with written forms that differ from their first language(s). Empirical research has demonstrated the influential role of written input on developing L2 phonology. However, existing studies are limited by (1) focusing on learning languages that share the same orthographic script, predominantly the Latin alphabet, (2) small sample sizes, and (3) limited consideration of L2 proficiency. This study investigated the influence of Arabic and English written input when lexically -encoding the difficult /f-v/ phonological contrast for L1 Arabic-speaking learners of L2 English. A word learning study was completed by 114 L1 Arabic-speakers, with varying English proficiency, and 117 L1 English-speaking controls. Mixed-effects modelling of L1 Arabic accuracy revealed an inhibitory effect of any written input when learning words differing by the difficult contrast. Performance improved with increasing L2 proficiency; however, the inhibitory effect of written input for words differing by /f-v/ persisted into high levels of L2 proficiency
Stone artefacts on submerged land surfaces:a response to Larcombe et al.
No full textLarcombe et al. (2025) challenge the work of the Deep History of Sea Country team regarding the provenance and mobility of lithic artefacts on the seafloor of Murujuga, Northwestern Australia. They propose that these artefacts were originally deposited on terrestrial Holocene landforms, and subsequently transported into the marine environment, challenging our interpretation of primary deposition on pre-inundation land surfaces. The authors largely base their conclusions on a hydrodynamic model and a 32-year satellite-derived shoreline dataset. Here we highlight the critical shortcomings in their approach including the application of a low resolution and poorly validated regional hydrodynamic model to infer current speeds at the local site level and by extension the transport of lithic artefacts at the seabed, and the analysis and interpretation of satellite derived shorelines which, when scrutinised, were found to be unrepresentative of real-world conditions. By emphasizing the importance of rigorous field validation and contextual site analyses, we reaffirm the preservation and integrity of Murujuga’s underwater cultural heritage, while challenging the scientific rigor of the conclusions presented by Larcombe et al