4208 research outputs found
Sort by
Geopolymer Chemistry and Composition: A Comprehensive Review of Synthesis, Reaction Mechanisms, and Material Properties—Oriented with Sustainable Construction
Full text linkGeopolymers are an environmentally sustainable class of low-calcium alkali-activated materials (AAMs), distinct from high-calcium C–A–S–H gel systems. Synthesized from aluminosilicate-rich precursors such as fly ash, metakaolin, slag, waste glass, and coal gasification fly ash (CGFA), geopolymers offer a significantly lower carbon footprint, valorize industrial by-products, and demonstrate superior durability in aggressive environments compared to Ordinary Portland Cement (OPC). Recent advances in thermodynamic modeling and phase chemistry, particularly in CaO–SiO2–Al2O3 systems, are improving precursor selection and mix design optimization, while Artificial Neural Network (ANN) and hybrid ML-thermodynamic approaches show promise for predictive performance assessment. This review critically evaluates geopolymer chemistry and composition, emphasizing precursor reactivity, Si/Al and other molar ratios, activator chemistry, curing regimes, and reaction mechanisms in relation to microstructure and performance. Comparative insights into alkali aluminosilicate (AAS) and aluminosilicate phosphate (ASP) systems, supported by SEM and XRD evidence, are discussed alongside durability challenges, including alkali–silica reaction (ASR) and shrinkage. Emerging applications ranging from advanced pavements and offshore scour protection to slow-release fertilizers and biomedical implants are reviewed within the framework of the United Nations Sustainable Development Goals (SDGs). Identified knowledge gaps include standardization of mix design, LCA-based evaluation of novel precursors, and variability management. Aligning geopolymer technology with circular economy principles, this review consolidates recent progress to guide sustainable construction, waste valorization, and infrastructure resilience
Gender dimension of climate-induced migration and access to ecosystem services in the Tatale/Sanguli District of the Northern Region of Ghana
Full text linkClimate-induced migration is an escalating global phenomenon with profound socio-economic and environmental implications. The intersection of gender dynamics and climate-induced migration presents unique challenges and opportunities that warrant further comprehensive investigation due to limited understanding of current issues facing specific localities and communities. Available literature is very vast, however, fails to explain definitive areal challenges and issues particularly dealing with unique gender inequalities. Migration also fuels competition for access to ecosystem services in border districts in the West-African Sub-region, where population is increasing due to migration against climate change effects. Using a mixed-methods approach and a survey of 250 respondents and 20 interview participants, in the Tatale/Sanguli District of the Northern Region of Ghana, this study finds that, prominently, access to ecosystem services in the local district largely depends on gender and migration status, and women migrants are more disadvantaged than any other groups. Women migrants only enjoy cultural services at par with their men colleagues and disproportionately higher than indigenous men, nonetheless, still less than their indigenous women counterparts in the district. The significance of the study is to offer a better understanding on migration due to climate change to highlight and direct interventions for access to resources and promote gender equity. This research therefore contributes to climate-migration studies by highlighting gender-specific impacts to inform policy and foster inclusive, resilient communities in climate-vulnerable regions
The Evolutions of Reflectarray Antennas for Small Satellites: Navigating to Design, Fabrication, and Performance Techniques
Full text linkClassical antennas in small satellites such as reflectors and phased arrays have encountered significant challenges, including restricted beam steering capabilities and complex deployment mechanisms. Reflectarray antennas have emerged as a promising alternative, offering a compact and lightweight solution. However, performance constraints related to high-gain, phase control, and multi-beam operation require continued innovation to meet the demands of long-distance communication. This article explores recent advancements in reflectarray antenna design, fabrication, and implementation techniques specifically tailored for small satellite platforms. The study traces the technological evolution of reflectarrays from the 1960s to the present, with a particular emphasis on deployment strategies including foldable and stowable configurations, as well as the integration of solar energy harvesting. A comparative analysis of various reflectarray architectures is presented, highlighting their electromagnetic performance characteristics and suitability for diverse mission profiles. The article also explores novel applications of reflectarrays in emerging domains such as low Earth orbit (LEO) satellite constellations, 6G communication networks, Earth observation, and defense systems. By addressing current challenges and identifying future research directions, this study aims to support the development of next-generation reflectarray systems for advanced small satellite applications
The landscape of musical care during the beginning of life in the United Kingdom: a mixed-methods survey study
Full text linkBackground: The first 1001 days of life are a critical time in children’s development and can be challenging for parents and caregivers. Some families in the United Kingdom (UK) are not getting the support they need. Research indicates that musical care – the role of music in supporting any aspect of people’s developmental or health needs – can support families during, what we term, the beginning of life: pregnancy to two years of age. Musical care activities can take place in health and community settings and include music making, music listening, and music therapy. We must describe and understand the patterns of use of musical care activities during the beginning of life in the UK to capitalise on the potential of musical care to support families. Methods: This article explores, from parents’ and musical care providers’ perspectives, (1) participation and provision of musical care activities, (2) descriptions and experiences of musical care activities, and (3) motivations for, deterrents from, and perceived outcomes of participation in musical care activities. Data from two co-developed cross-sectional surveys for parents/caregivers (N = 578) and providers (N = 50) was analysed using descriptive statistics and thematic analysis. Results: Most parent/caregivers had participated in at least one musical care activity (83%). The most attended activity was play and development groups for babies that involve some music. Following our thematic analysis, personal preference, experiential and practical factors, recommendation by healthcare providers, and expectation of benefit were identified as motivators while deterrents included challenges in resources and logistics, and lack of inclusivity and diversity. Parents/caregivers perceived both positive and negative outcomes of attending musical care activities. Most providers had not had specific training and for many this work was not their primary income source. Conclusions: There is a wide range of musical care activities during the beginning of life in the UK. Reasons for attending them range from those specific to music and its care potential to seeing them as leisure activities. The findings have implications for the flexibility and role that musical care activities can play during the beginning of life and call for investigation into how musical care activities may be integrated into care
Exploring the support mechanisms to facilitate the uptake of bowel screening: A Group Concept Mapping study
Full text linkBowel cancer is a common cancer and the second leading cause of cancer mortality worldwide. Bowel screening aims to improve early detection and reduce mortality. Barriers to screening uptake are often associated with sociodemographic factors, cultural/religious issues, practical issues, psychological barriers, and lack of knowledge and awareness of the screening. However, little is known about the support required to remove these obstacles. A Group Concept Mapping study was carried out to explore the support mechanisms to facilitate the uptake of bowel screening from the perspectives of people living in an area of low uptake rate in Wales. A participatory, structured, mixed-methods approach called Group Concept Mapping was applied. Twenty-four participants were recruited and completed brainstorming, sorting and rating activities either online or offline. Fifty-six statements were generated and sorted into five conceptually similar clusters: ‘Easy-to-use test kits’; ‘Practical support’; ‘General Practitioner involvement’; ‘Information tailored to individual needs’; ‘Raising awareness and understanding of bowel screening’. Perspectives differed based on gender, disability and ethnicity. The findings highlight five broad areas of support that need to be addressed to facilitate the uptake of bowel screening. Health promotion interventions designed to improve screening uptake should consider a collective effort of providing simple and easy-to-use test kits, General Practitioner involvement, individualised practical support when required especially relating to gender and disability, accessible information, and awareness raising
Can Artificial Intelligence Revolutionise Surgical Decision-Making for Appendectomy? A Narrative Review
Full text linkIntroductionAcute appendicitis is a common cause of acute abdomen in secondary care. Despite advancements in diagnostics, misdiagnosis and negative appendectomies remain significant. Artificial Intelligence (AI), particularly machine learning (ML) and deep learning, shows promise in improving diagnostic accuracy.Materials and MethodsA literature review using PubMed and Cochrane databases included studies on AI's role in diagnosing and prognosing appendicitis. Studies relying solely on clinical or radiology reports were excluded.ResultsAI models, particularly random forest (RF), logistic regression (LR), and neural networks (NN), demonstrated high diagnostic accuracy, with RF outperforming others. Machine learning methods like SVM and XGBoost (XGB) were effective in predicting appendicitis prognosis, especially in distinguishing complicated cases. AI models outperformed traditional diagnostic scores, such as the Alvarado score.ConclusionAI has significant potential to enhance the diagnosis and prognosis of acute appendicitis, but challenges in data requirements and standardisation must be addressed for widespread clinical use
