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Blending interventions to achieve green hydrogen cost competitiveness for industrial decarbonisation
No full textIndustrial decarbonisation can be supported by green hydrogen as a fuel and feedstock, but its cost remains too high to compete with natural gas. In this study, the achievement of cost competitiveness for green hydrogen is examined through a combination of internal interventions, including the reduction of electrolysis costs via waste heat sales to district heating networks and the use of curtailed wind, alongside external interventions such as market-based policies and sustainability-linked bonds. A novel temporal market penetration assessment model has been developed and applied to evaluate the impact of these interventions, both individually and in combination, on achieving cost parity. The methodology has been implemented in a UK case study to assess these dynamics within the energy landscape and policy framework. The findings indicate that cost reductions of 17.5 % can be achieved through hydrogen from curtailed wind, while waste heat utilisation contributes a 24.7 % reduction. Existing policy measures are found to have the potential to lower costs by 39 %. A total cost reduction of 78 % is observed when interventions are blended, with green hydrogen from curtailed wind projected to reach cost parity with natural gas by the mid-2030s under high natural gas price scenarios. The feasibility of blended interventions in facilitating the industrial adoption of green hydrogen is thereby demonstrated
Randomized Nyström approximation of non-negative self-adjoint operators
No full textThe randomized singular value decomposition (SVD) has become a popular approach to computing cheap, yet accurate, low-rank approximations to matrices due to its efficiency and strong theoretical guarantees. Recent work by Boullé and Townsend [Found. Comput. Math., 23 (2023), pp. 709–739] presents an infinite-dimensional analogue of the randomized SVD to approximate Hilbert–Schmidt operators. However, many applications involve computing low-rank approximations to symmetric positive semi-definite matrices. In this setting, it is well established that the randomized Nyström approximation is usually preferred over the randomized SVD. This paper explores an infinite-dimensional analogue of the Nyström approximation to compute low-rank approximations to non-negative self-adjoint trace-class operators. We present an analysis of the method and, along the way, improve the existing infinite-dimensional bounds for the randomized SVD. Our analysis yields bounds on the expected value and tail bounds for the Nyström approximation error in the operator, trace, and Hilbert–Schmidt norms. Numerical experiments on integral operators arising from Gaussian process sampling and Bayesian inverse problems are used to validate the proposed infinite-dimensional Nyström algorithm
Effects of laser powder bed fusion parameters on the delta-ferrite to austenite phase transformation in duplex stainless steels
No full textLaser powder bed fusion (LPBF) of 2205 duplex stainless steels is attractive for making complex shaped engineering parts for applications requiring unique combinations of strength-toughness-corrosion properties. However, as-built parts possess highly non-equilibrium microstructures (>98 % δ-ferrite). The desirable balanced austenite/δ-ferrite microstructure can be recovered after a brief heat treatment, potentially achieving much finer duplex microstructures than in wrought counterparts. However, systematic understanding of how LPBF parameters control the microstructural characteristics of the parent δ-ferrite and, hence, the transformed austenite product, is currently missing. We aim to close this gap by establishing the process-microstructure-property relationship using multi-scale characterization and nano-indentation. We compare as-built and heat-treated conditions fabricated with eight different combinations of laser power and scan speed. We show how variations in residual stress, texture, and characteristics of dislocations and inclusions in the parent δ-ferrite control the phase fraction, morphology, grain size, texture, and variant selection of the daughter austenite. A higher dislocation density in δ-ferrite is found to be associated with lower laser power and/or higher scan speed, contributing to higher hardness in as-built δ-ferrite and smaller intragranular austenite grain sizes in heat-treated conditions. Higher residual stress and/or stronger δ-ferrite texture contribute to higher austenite phase fractions. Intragranular austenite variant selection is revealed to be related to the complexity of δ-ferrite dislocation structures, and results in significant hardness increments in the heat-treated conditions. These findings highlight the capability of microstructural engineering via adjusting LPBF parameters and controlling materials performance through manipulating solid-state phase transformations
Late-life affective disorders and risk of progression to dementia: retrospective cohort study of patients in secondary care
No full textBackground:
Late-life affective disorders (LLADs) are common and are projected to increase by 2050. There have been several studies linking late-life depression to an increased risk of dementia, but it is unclear if bipolar affective disorder or anxiety disorders pose a similar risk.
Aims:
We aimed to compare the risk of LLADs progressing to all-cause dementia, and the demographic and clinical variables mediating the risk.
Methods:
We used the South London and Maudsley National Health Service Foundation Trust Clinical Records Interactive Search system to identify patients aged 60 years or older with a diagnosis of any affective disorder. Cox proportional hazard models were used to determine differences in dementia risk between late-life anxiety disorders versus late-life depression, and late-life bipolar disorder versus late-life depression. Demographic and clinical characteristics associated with the risk of dementia were investigated.
Results:
Some 5695 patients were identified and included in the final analysis. Of these, 388 had a diagnosis of bipolar affective disorder, 1365 had a diagnosis of an anxiety disorder and 3942 had a diagnosis of a depressive disorder. Bipolar affective disorder was associated with a lower hazard of developing dementia compared to depression (adjusted model including demographics and baseline cognition, hazard ratio: 0.60; 95% CI: 0.41–0.87). Anxiety disorders had a similar hazard of developing dementia (adjusted hazard ratio: 1.05; 95% CI: 0.90–1.22). A prior history of a depressive disorder reduced the risk of late-life depression progressing to dementia – suggesting the new onset of a depressive disorder in later life is associated with higher risk – but a prior history of anxiety disorders or bipolar affective disorder did not alter risk.
Conclusions:
LLADs have a differential risk of developing all-cause dementia, with demographic- and illness-related factors influencing the risk. Further prospective cohort studies are needed to explore the link between LLADs and dementia development, and mediators of the lower risk of dementia associated with late-life bipolar disorder compared to late-life depression
Concordance between FVC and FEV6 for identifying chronic airflow obstruction and spirometric restriction in the Burden of Obstructive Lung Disease (BOLD) study
No full textIntroduction: We investigated whether the forced expiratory volume in six seconds (FEV6) can be used
as a surrogate for the forced vital capacity (FVC).
Methods: The Burden of Obstructive Lung Disease is a multinational cohort study. At baseline, data were collected from adults, aged 40 years or older, from 41 sites across 34 countries. Participants from eighteen sites were followed-up after a median of 8.3 years. Participants who completed the study core questionnaire and had acceptable post-bronchodilator spirometry were included. We performed receiver operating characteristic (ROC) analyses to measure the ability of FEV1/FEV6 less than the LLN to correctly classify FEV1/FVC less than the LLN, and FEV6 less than the LLN to correctly classify FVC less
than the LLN. We used multi-level regression analyses to assess the association of discordant measurements with respiratory symptoms, quality of life and lung function decline.
Results: At baseline, 28 604 participants were included. 53% were female (15 060). Ten percent (2876) had chronic airflow obstruction for FEV1/FVC, compared to 9% (2704) for FEV1/FEV6. Thirty-seven percent (10 637) had spirometric restriction for FVC, compared to 35 (9978) for FEV6. The FEV1/FEV6 had excellent accuracy in identifying FEV1/FVC less than the LLN (area under the curve (AUC): 0.90, 95% CI, 0.89-0.91, κ coefficient 0.82). The FEV6 also had excellent agreement in identifying FVC less
than the LLN (AUC: 0.95, 95%CI, 0.94-0.95, κ coefficient 0.90). Discordant reductions in FEV1/FEV6 (1%, 345) and FEV6 (1%, 309) were associated with greater odds of having respiratory symptoms and a lower physical quality of life. 3870 participants were followed up. Those with discordant reductions in FEV1/FEV6 and FEV6 were more likely to have chronic airflow obstruction and spirometric restriction at follow-up.
Conclusions: There is strong agreement between the FVC and FEV6 in the identification of chronic airflow obstruction and spirometric restriction
Cerebral oxygenation measurements during immediate neonatal transition in the delivery room: a systematic review
No full textObjective
To systematically review the use of NIRS measured cerebral oxygenation and analyse these parameters during the immediate postnatal period.
Data Sources
EMBASE, MEDLINE, and Maternity and Infant Care databases using keywords: “Infants,” “NIRS,” and “Cerebral oxygenation.”
Study selection
Inclusion criteria were clinical trials and observational studies measuring cerebral oxygenation up to 15 min of life. Exclusion criteria were non-human studies, non-English articles and case reports.
Data extraction
Two authors independently performed study selection, data extraction, and risk of bias assessment. Cerebral regional tissue Oxygenation (CrSO2) and cerebral fractional tissue oxygenation extraction (cFTOE) values were extracted.
Results
Fifty nine studies, out of 4067 were included in the qualitative analysis. Studies included aimed to establish oxygenation reference ranges, assess the impact of delivery mode, cord clamping, and delivery room interventions on cerebral oxygenation, and evaluated its role in predicting long-term neurodevelopmental outcomes. Most studies focused on term neonates experiencing normal neonatal transitions. Aggregate mean values for CrSO2 and cFTOE in the first 15 min of life were calculated, showing that a steady state is achieved by 10–15 min of life. ANOVA demonstrated no significant differences between preterm and term infants in CrSO2 (p = 0.54) and cFTOE (p = 0.50).
Conclusions
NIRS measurement of CrSO2 is feasible and can be used alongside other clinical tools to inform delivery room management. There were no significant differences in CrSO2 or cFTOE between term and preterm infants although most studies focussed on late preterm infants. Future research is therefore required for extremely preterm infants, those requiring ventilatory management, or those with congenital anomalies
Domestic cultures of plant care: a moss terrarium probe
No full textHouseplants are increasingly being used as part of interactive sys- tems that aim to foster pro-environmental concern and awareness of more-than-human life. Yet such interventions rely on conflicting and untested assumptions about how people relate to houseplants. We therefore studied domestic plant care in 11 purposefully sampled households, applying a sensor-equipped moss terrarium as a living ‘thing ethnography’ probe, supplemented with semi-structured in- terviews. We find that social and intergenerational cultures of plant care inform people’s individual concern and accountability through constituents and mechanisms like gift-giving, signalling, knowledge transfer, or joint practical care. We identify five domestic cultures of plant care in our sample, each of which frames plants differently and leads to different practical approaches to plant care. We propose design considerations that emphasise enculturation and shared care over individual behaviour change and reframe houseplants from decorative objects into living household members
Matching frictions and distorted beliefs: evidence from a job fair experiment
No full textWe evaluate the impacts of a randomized job-fair intervention in which jobseekers and employers can meet at low cost. The intervention generates few hires, but it lowers participants’ expectations and causes both firms and workers to invest more in search as predicted by a theoretical model; this improves employment outcomes for less-educated jobseekers. Through a unique two-sided belief-elicitation survey, we confirm that firms and jobseekers have over-optimistic expectations about the market. This suggests that, beyond slowing down matching, search frictions have a second understudied cost: they entrench inaccurate beliefs, further distorting search strategies and labour-market outcomes
Pore- and density-related characteristics of a lightweight aggregate
No full textPorous lightweight aggregates are frequently used in civil engineering to produce low-density concrete. As individual particles contain air voids (micropores), when evaluating particle assemblies it is necessary to consider both micro- and macro-porosity. Micropores are important when assessing water absorbency as they affect cement–water ratios and can be used to store self-healing admixtures/agents for slow release during curing. The physical characteristics of ‘Lytag’ are investigated, namely particle density, porosity, water absorption and dry density. The apparent particle density, ρa, of Lytag particles at their manufactured size and shape (typically 4–14 mm) is about 2.00 t/m3 because of the presence of micropores. This value increases to a maximum, intrinsic, ρs, value of about 2.62 t/m3 as particle size is progressively reduced through grinding to minimise the effects of micropores. With apparent and intrinsic density values known, micro- and macro-pore porosity can be established. Water absorption, measured with time, under negative, atmospheric and elevated pressures, is compared with theoretical values. The role of capillarity on water absorption is assessed conceptually using the Young–Laplace formulation. Combined, these characteristics provide insights into the time-dependent absorbency capacity of lightweight porous particles, which is relevant when used in concrete, filtration beds and backfill
Clustering pulmonary hypertension patients using the plasma proteome
No full textIntroduction: Patients with pulmonary hypertension are classified according to clinical criteria to inform treatment decisions. Knowledge of the molecular drivers of pulmonary hypertension might better inform treatment choice. Methods: Between 2013 and 2021, 470 patients with pulmonary hypertension, 136 disease controls and 59 healthy controls were enrolled as a discovery cohort. Plasma levels of 7288 proteins were assayed (SomaScan 7K platform). Proteins that distinguished pulmonary hypertension from both control groups were selected for unsupervised clustering (k-means clustering of UMAP dimensions). Clinical characteristics and outcomes were compared across clusters. Separate cohorts of serially sampled patients from pulmonary hypertension centers in the United Kingdom (n=229) and France (n=79) provided independent validation. Results: 156 plasma proteins that distinguished pulmonary hypertension from disease and healthy controls formed 4 clusters with diverse 5-year survival rates: 78% (cluster 4), 62% (cluster 2), 44% (cluster 3), and 33% (cluster 1). The distinction and clinical relevance of the clusters were confirmed in validation cohorts by their association with survival. To further characterise the therapeutic relevance of the clusters we investigated 2 experimental drug targets: the Platelet-Derived Growth Factor (PDGF) pathway was up-regulated in cluster 3 compared to other clusters and the Transforming Growth Factor-β (TGF-β) pathway was up-regulated in cluster 1. Conclusion: Plasma proteomic profiling of patients with pulmonary hypertension distinguishes 4 clusters, independent of the clinical classification. These groups, based on differential plasma protein levels, could act as theragnostic biomarkers for new therapies targeting PDGF and TGF-β pathways. This article is open access and distributed under the terms of the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/)