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Measurement of phase transition, density and viscosity of supercritical carbon dioxide-Fischer-Tropsch wax mixtures2025

(2025-06) Swanepoel, Andri; Labuschagne, Philip W; Schwarz, CE

Melting temperature, phase behaviour and densities of binary mixtures of CO 2 and three Fischer-Tropsch waxes with varying molecular weights were experimentally determined. The melting temperatures of the lower molecular weight waxes increased with CO 2 pressure, and pressure induced crystallisation of the lowest molecular weight wax occurred above 20 MPa. CO 2 solubility in the waxes decreased with increasing wax molecular weight. Trends in mixture densities with changes in temperature and pressure mimicked that of pure CO viscosity of the lowest molecular weight wax decreased with increased CO 2 2 . The concentration, and decreased with increases in temperature and pressure, with the impact of pressure minimised above the temperature inversion point. Solubility data were correlated with a modified Chrastil and the Mendez-Santiago & Teja models. The Chrastil model accurately predicted solubility of CO 2 in all three waxes to within 1 % of the measured values.

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Effect of Cowpea Lignocellulosic Fibers as a Low-Value Reinforcing Filler on the Properties of Poly(butylene succinate-co-adipate) Bio-Composite Foams

(2025-03) Masanabo, MA; Keränen, JT; Ray, Suprakas S; Emmambux, MN

Herein, fully bio-based and biodegradable bio-composite foams are produced from poly(butylene succinate-co-adipate) (PBSA), reinforced with low-value , and azodicarbonamide as a chemical blowing agent. These are produced by melt extrusion followed by compression molding. Fiber addition increases the melt viscosity and melt strength, this restricts uncontrolled bubble growth during foaming to decrease the bubble size. The bio-composite foam containing 15% fibers has the largest decrease in bubble size from 209 μm in the unfilled PBSA foam to 95 μm in the foam containing 15% fibers. Fiber addition significantly increases the bubble density, from ≈1.05 × 109 cells cm−3 in the unfilled PBSA foam to 5.13 × 109 cells cm−3 in bio-composite foam containing 15% fibers, due to heterogeneous bubble nucleation induced by the fibers. The stiffness of the bio-composite foams increases with fiber addition, with the bio-composite foam containing 15% showing the largest increase relative to the unfilled PBSA foam as revealed by dynamic mechanical analysis. In conclusion, the f ibers not only induce heterogeneous bubble nucleation to increase bubble density and decrease bubble size during the foaming of PBSA, but also act as reinforcement to increase the stiffness of the bio-composite foams. These bio-composite foams have potential applications in packaging and agriculture.

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Sustained gamification in medication adherence: Strategies and conceptual framework

(2025-03) Adetunji, RO; Botha, Adele; Herselman, Martha E

This paper examines the current body of literature on medication adherence using sustained gaming strategies and approaches. The objective is to investigate the concepts of sustained gaming, gaming strategies, and gaming approaches in relation to medication adherence. The goal is to identify the elements that contribute to a conceptual framework for understanding medication adherence behavior in patients, as part of a broader study. A comprehensive literature review was performed on four scholarly databases: MEDLINE, BMC, Global health, and Embase. The study examined the strategies and methodologies employed by the Pokémon Go game as a location-based game (LBG), and its impact on patients' adherence to medication. The study has identified several components, namely physical activities, social connections, exploration, enhanced emotional expression, and Marlien Herselman Council of Scientific and Industrial Research, Pretoria South Africa Technology for Development (ICT4D) viewpoints should encompass various aspects, including economic, ecological, educational in nature, political, cultural, and technological dimensions [10-12]. The concept of sustainability has gained significant attention in the field of Information Systems [8, 13] while the concept of long-term gaming strategies and approaches is seldom addressed and has yet to be thoroughly examined in scholarly literature. Furthermore, there is a lack of theoretical research that specifically examines the use of strategies and approaches for sustained gaming in relation to medication adherence. This article aims to identify the strategies, approaches, and gaming experiences that promote sustained gaming in order to develop a conceptual framework for medication adherence in patients focusing on Pokémon Go as a game. This study adds to the growing body of knowledge in the field of digital health, gaming and medication adherence. individual/self-treatment. The study conducted a qualitative examination on Pokemon Go players to understand their experiences and what kept them playing the games for a longer period. Therefore, the findings from the study and data analysis helped in the development of conceptual framework for promoting medication adherence using sustained gaming strategies and approaches is hereby presented. The results of this study have the potential to contribute to a shared comprehension among practitioners, professionals, and academics in the field of digital health and serious games. Additionally, these findings can serve as a foundation for future research on the long-term viability of digital health through gaming.

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Physical oceanographic indicators for proactive management and early warning of harmful algal blooms

(2025-03) Mtetandaba, A; Veitch, J; Smith, Marié E

Harmful algal blooms (HABs) represent a significant threat to both the environment and the economy, particularly in coastal zones where aquaculture is a vital industry. These blooms, caused by the rapid growth of algae, can produce toxins that are detrimental to marine life, lead to hypoxic conditions (low oxygen levels), and contaminate seafood, posing risks to human health. The economic impact is substantial, as HABs can devastate fish populations, disrupt aquaculture operations, and result in costly closures of fisheries and tourism activities. Effective monitoring and prediction of HABs are therefore crucial for protecting marine ecosystems and ensuring the sustainability of aquaculture practices.

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Assessment of the inland wetland ecosystem types in South Africa: threats and protection

(2025-04) Van Deventer, Heidi; Nel, JL

Ecosystem threat status (ETS) and ecosystem protection levels (EPLs) are headline indicators that can assess freshwater ecosystems at a country-wide scale. A spatial layer of freshwater, inland wetland ecosystem types of South Africa was combined with a range of spatial data sets to model their ecological condition. The ETS and EPL of each ecosystem type were determined using the area of that type in good ecological condition relative to a biodiversity target, which represented 20% of the total area of that ecosystem type. Thresholds were applied to distinguish four ETS categories ranging from Least Concern to Critically Endangered, and four EPL categories ranging from Not Protected to Well Protected. A total of 79% of the 135 of South African inland wetland ecosystem types were found to be threatened, of which 83 (62% of the number of types) are Critically Endangered, 12 (9%) are Endangered, 12 (9%) are Vulnerable and 28 (21%) of Least Concern. Of the 135 inland wetland types, 61% were Not Protected, with 6% being Well Protected, 3% Moderately Protected, and 30% Poorly Protected. Protected and Ramsar sites hosted only 7% of the total area of inland wetlands, which means that the Aichi Biodiversity Target 11 for 2020 (17%) was not met.