Towards maximum cost-effectiveness: multi-objective design optimisation of insulating glass flat-plate collectors

open access articleA significant challenge in the advancement of solar thermal heating systems lies in the unexplored techno-economic potential of insulating glass flat-plate collectors. These collectors are constructed in accordance with the specifications of standard insulating glass units and have emerged over the past decade as a promising design concept for enhancing the cost-effectiveness of solar thermal systems. However, substantial findings regarding the techno-economic viability of their production are still pending. The aim of this paper is to optimise insulating glass collector designs for solar district heating applications by identifying key design parameters that maximise cost-effectiveness. This study employed a five-stage methodology. It included thermo-hydraulic collector modelling using MATLAB/Simscape and the CARNOT Toolbox. The model was validated against experimental performance tests. A Latin hypercube computational design with 250,000 samples was set up to train supervised machine learning metamodels and perform a multi-objective optimisation using an elitist genetic algorithm. The study identified the argon concentration, collector length, and width as critical parameters influencing efficiency. Larger, thinner collectors demonstrated superior performance due to reduced convective losses and increased aperture-to-surface ratios. The optimisation revealed that the insulating glass collectors could achieve a 7.7 percentage point increase in efficiency, a 19.4 % reduction in material cost, and a 14.5 % decrease in weight compared to market-available flat-plate collectors. However, the direct economic comparison was not considered strong in evidence due to a lack of economic data from technology providers. The most cost-effective designs featured an argon concentration of 99 %, sealing thickness of 31.2 mm, and a glazing thickness of 4.1 mm, and 4.5 mm, while collector length and width varied more significantly. The research findings indicate the techno-economic potential of insulating glass collectors, demonstrating their ability to outperform conventional flat-plate collectors in terms of cost-effectiveness and efficiency. Future studies should focus on producing and testing larger modules and incorporating production costs to fully realise their potential for solar district heating applications. This study provides valuable guidelines for IGU designers and producers aiming to develop cost-effective and efficient solar thermal collectors for district heating systems

Help-seeking and access to care for stroke and heart attack during the COVID-19 pandemic: a qualitative study.

open access articleIn this paper we explore how people who experienced a stroke, transient ischaemic attack (TIA), or heart attack sought health care during the COVID-19 lockdown periods. Semi-structured interviews were conducted with 27 patients admitted to hospital between March 2020 and May 2021, and one carer, recruited from cardiac and stroke rehabilitation services in two large acute NHS trusts in England. Drawing on concepts of candidacy, illness and moral work, we discuss how people’s sense-making about their symptoms fundamentally shaped both their decisions about seeking help, and the impact of COVID-19 on help seeking. Risk perception and interactional ritual chain theory allow further exploration of constructing symbols of national identity in times of crises, managing risk and levels of acceptable risk, and critique of ambiguous national messaging over accessing healthcare services for people with emergency healthcare needs. Our findings have wider implications for supporting access into healthcare for those with life-threatening conditions under highly publicised strain on the health system, including winter pressure and staff strikes, also policy-making and public messaging

Effectiveness of different antioxidants in suppressing the evolution of thermally induced peroxidation products in hemp seed oil

open access articleSeveral scientific studies have warned that the ingestion of dietary lipid oxidation products (LOPs) may initiate or exacerbate the development of several chronic non-communicable diseases in humans. Indeed, the constantly increasing consumption of culinary oils by larger global populations indicates the need for scientific techniques to suppress the evolution of LOPs in thermo-oxidised oils. This study employed a 600.13 MHz frequency NMR spectrometer in evaluating the effect of 10, 50, and 100 ppm concentrations of chemical compounds reported to have antioxidant properties in continuously-stirred and thermally stressed polyunsaturated fatty acid (PUFA)-rich hemp seed oil at a frying temperature of 180℃ for 180 min. Research data acquired showed that the antioxidants α- and γ-tocopherol, γ-oryzanol, β-carotene, eugenol, resveratrol, ascorbyl palmitate, gentisic acid, and L-ascorbic acid all played a vital role in suppressing the evolution of secondary aldehydic lipid oxidation products in hemp seed oil. However, the most ineffective LOP-suppressing agent was L-lysine, an observation which may be accountable by its poor oil solubility. Nonetheless, trends deduced for compounds acting as antioxidants were mainly unique for each class of agent tested. Conversely, the antioxidant capacity of resveratrol was consistently higher, and this effect was found to be independent of its added amounts. This report provides a direct approach in developing scientific methods for the suppression of LOPs in thermo-oxidatively susceptible PUFA-rich cooking oils

Exploring dental anxiety as a mediator in the relationship between mindfulness or self-compassion and dental neglect

open access articleDental anxiety and dental neglect are interconnected constructs with profound consequences for oral health and corresponding challenges for dental professionals. Meanwhile, other literature has indicated that mindfulness and self-compassion relate negatively to different forms of anxiety, and propose elements of potential interventions. This study aimed to explore the potential impact of dental anxiety as a mediator on the relationships between mindfulness or self-compassion and dental neglect. The results showed significant negative associations between mindfulness and self-compassion with dental anxiety and dental neglect. Mediation analyses supported the hypothesis that dental anxiety mediates the positive associations between mindfulness or self-compassion and dental neglect, providing preliminary evidence for the potential effectiveness of mindfulness and self-compassion interventions in addressing dental anxiety and dental neglect. Future research and potential clinical implications are discussed

Continuous variation operator configuration for decomposition-based evolutionary multi-objective optimization

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.There are various multi-objective evolutionary algorithms (MOEAs) for solving multi-objective optimization problems (MOPs), and the significant difference between them lies in the way they generate offspring, which are the so-called variation operators. Since different variation operators have their own characteristics, it is often tedious to select a suitable EA for a given MOP. Even if the optimal operator is assigned, the fixed operator and hyper-parameters make it difficult to balance exploration and exploitation during the evolutionary process. It is imperative to configure variation operators and hyper-parameters automatically during the evolutionary process, which can improve the efficiency of algorithm search. However, numerous configurations only consider operators or discretize hyper-parameters, making it difficult to achieve satisfactory results. In this paper, we formulate the operator configuration as a continuous Markov Decision Process (MDP) and use a suitable Reinforcement Learning (RL) paradigm to realize the online configuration of EAs. To simplify the deployment of MDP, we adopt a decomposition-based framework and use a one-dimensional vector with a combination of weights and objectives as state spaces. In addition, we take the selection of crossover and mutation operators and the fine-tuning of their hyper-parameters as joint action spaces. With an RL technique, we expect to achieve maximum improvement in the performance of offspring on each preference by selecting an action in a given state. We further explore the effectiveness of the proposed methodology on different characteristic MOPs. Experimental results show that our method is more competitive than other configurations and state-of-the-art EAs

How is men’s mental health affected within male professional football?

open access articleResearch question: How is men’s mental health affected within male professional football? Research methods: Within this qualitative study, eighteen current first-team professional footballers were interviewed from across the English Football League (EFL) to explore how male professional footballers are affected by mental health. Braun and Clarke’s thematic analysis (2006) was applied along with “The Silences Framework” [Serrant-Green, L. (2010). The sound of “silence”: A framework for researching sensitive issues or marginalised perspectives in health. Journal of Research in Nursing, 16(4), 347–360] to allow the voices of this marginalised group to be heard. Results and findings: The five key themes of social networks, environment, masking vulnerabilities, help-seeking and support, and mental health emerged from the data. The mental health theme is split into two sub themes: impact on self and reaction of others. Implications: This study makes an original contribution to the knowledge base as it is the first study to innovatively apply The Silences Framework to a sporting context. This study has applied The Silences Framework to show that professional footballers are affected by their mental health, and without appropriate access to support they continue to suffer in silence. This is likely to have negative consequences in their personal life, their football career, and their eventual transition away from being a professional footballe

Electromagnetic time reversal for online partial discharge location in power cables: Influence of interfering reflections from grid components

open access articleIn online single-sided partial discharge (PD) location, the measured PD reflection patterns are affected by the characteristics of all the components of the associated power network. This paper analyses the performance of a PD location method based on electromagnetic time reversal (EMTR) theory, when interfering reflections contribute to the transient signals emitted by the PD event. The topology analysed is formed from a ring main unit (RMU) in a medium voltage grid with mixed cross-linked polyethylene and paper-insulated lead-covered (PILC) cable sections. The PD reflection patterns, observed at the RMU, are disturbed by the reflections coming from the impedance discontinuities of the circuit and by the reflections coming from the cable ends of the PILC cables connected to the RMU. The simulated configuration is chosen such that classical location techniques tend to fail due to overlapping peaks and other signal distortion. This is because the classic techniques are based on identifying individual reflection peaks from which the PD source can be determined via differences in time of arrival. The numerical investigation shows that the accuracy of the EMTR-based location method is robust against these effects, achieving a PD localisation with an error less than the 0.1%. The results also show that the EMTR-based method can localise PDs using a PD monitoring point located somewhere along the network and not necessarily at the line termination

Exploring salivary metabolic alterations in type 2 diabetes: Implications for dental caries and potential influences of HbA1c and vitamin D levels

open access articleDiabetes mellitus is considered to be the most common health issue affecting almost 1 in 11 adults globally. Oral health complications including xerostomia, periodontal disease, dental caries, and soft tissue lesions are prevalent among individuals with diabetes, and therefore an understanding of the potential association between salivary metabolites and dental caries progression would enable the early detection and prevention of this non-communicable disease. Therefore, the aim of this study was to compare salivary biomarkers between individuals with type 2 diabetes (T2DM) with those without this disorder (ND) using 1H NMR-based metabolomics strategies. The objectives were to identify T2DM-associated biomarker signatures and their potential impact on dental caries. In addition, HbA1c and vitamin D levels were also analysed for this purpose. Methods: Stimulated whole-mouth saliva (SWS) samples were collected from T2DM and ND (n = 30 in each case) participants randomly selected from a group of 128 participants recruited for this case–control study. All participants were advised to refrain from eating, drinking, and smoking for at least 1–2 h prior to sample collection. Following preparation, SWS supernatants underwent 1H NMR analysis at an operating frequency of 800 MHz, and the dataset acquired was analysed using a range of multivariate metabolomics techniques. Results: Metabolomics analysis of data acquired demonstrated that, together with up- and downregulated blood HbA1c and vitamin D levels, key salivary discriminators between these two classifications included lactate, taurine, creatinine, α-glucose, and formate to a lesser extent. The bacterial catabolites lactate and formate were both significantly upregulated in the T2DM group, and these have previously been implicated in the pathogenesis of dental caries. Significance analysis of metabolites (SAM)-facilitated AUROC analysis yielded an 83% accuracy for this distinction. Conclusion: In conclusion, this study highlights the significant differences in salivary metabolites between individuals with T2DM and healthy controls. Such differences appear to be related to the development and progression of dental caries in T2DM patients

Exploring blue-green roof for a sustainable built environment in South Africa

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.Purpose – The current adverse changes in climatic conditions have necessitated innovative nature-based solutions like blue-green roofs to ensure sustainable built environments. The use of blue-green roofs in combating climate change issues has continued to grow, and its benefits are showcased in many countries’ studies. However, there is an absence of reports on the use of this approach in South Africa. Therefore, in ensuring a sustainable built environment through nature-based solutions, this study explored the built environment professional’s knowledge of blue-green roofs, the hindrances to their use and motivations for much wider use of blue-green roofs in the country. Design/methodology/approach – Based on the nature of the study, a quantitative design was adopted and data were obtained from professionals within the built environment through a questionnaire. Data analyses were conducted using the Cronbach alpha test, Kruskal–Wallis H-Test, exploratory factor analysis and fuzzy synthetic evaluation. Findings – The findings revealed a growing knowledge of blue-green roofs, albeit its slow adoption in the country. Also, five critical clusters of hindrances affecting the use of blue-green roofs were identified. These are understanding the blue-green roof concepts, technical, economic, regulation and client hindrances. Furthermore, the ability to manage stormwater properly, provide climate change adaptation and deliver sustainable buildings were the key motivating factors that could drive the use of this innovative solution. Practical implications – This study offers actionable insights for built environment professionals and stakeholders to address the hindrances to using blue-green roofs in South Africa. Strategies such as improved education, financial incentives and policy development can help overcome some notable hindrances and promote the widespread adoption of blue-green roofs. Originality/value – The slow adoption of blue-green roofs and the scant nature of research within the built environment required adequate attention to which this current research contributes. Theoretically, being one of the foremost studies in South Africa to explore blue-green roofs, the findings offer a foundation for future studies seeking to explore this roofing system in the country further

HRD Practitioner Roles in Organizations: Challenges, Congruence and Changes

This chapter focusses on the HRD roles performed by present day organization-based professional “HRD practitioners” and their respective colleague managers. In the absence of a universally accepted definition of the HRD domain of practice, our thinking was guided by Ruona (2016) who suggests both practitioners and scholars could lean on Hamlin and Stewart’s (2011) assertion that HRD is “in essence, a process or activity that helps or enables individuals, groups, organizations or host systems to learn, develop, and change behaviour for the purpose of improving or enhancing their competence, effectiveness, performance and growth” (p. 213). We have used their conceptualization of HRD to inform our thinking for this chapter. Little is known about the extent to which HRD organizational practitioners perform the core roles of HRD practice because, as Garavan et al. (2020) claim: (i) there is a dearth of research on such roles and the associated competencies; and (ii) there has been very limited progress in the alignment and strategic impact of HRD as advocated by HRD scholars and professional bodies, over the past 25 years. Research shows that many HRD practitioners lack credibility in the eyes of line managers (Thornhill et al., 2000; Hamlin, 2001; Torraco & Lundgren, 2020) with many line managers perceiving them as lacking the necessary business-related competencies to be an effective “strategic partner” (Garavan et al., 2020). Research also shows that many line managers fail to appreciate the critical importance of their own role within the HRD domain, supported by HRD practitioners, bringing about effective organizational change, development, and sustainable business success (Hamlin, 2016). In short, HRD research shows that there is a discrepancy between what HRD is doing, and what HRD should be doing (Torraco & Lundgren, 2020). In response to the above lack of research and role misunderstanding, the purpose of this chapter is to explore the HRD roles and activities performed by HRD practitioners and managers within organizational contexts, to clarify HRDs contribution and highlight areas to build future credibility. This is achieved by discussing previous and current research including the results of a recent HRD role-related cross-case/cross-nation comparative study using empirical data previously collected in the USA, the UK, and the NL, respectively (Stewart et al., 2022). The specific research question addressed was as follows: To what extent is there congruence in role expectations of organization-based HRD practitioners and their colleague/line managers