Fibre/matrix intermetallic phase formation in novel aluminium-basalt composites

A novel aluminium-basalt metal matrix composite has been produced by employing a combination of stir mixing and ultrasonication processing techniques. A study of the matrix-fibre interface has revealed the formation of Al-Si-Ca and Al-Fe-Si-Mn intermetallic compounds (IMC) with both phases displaying a polyhedral morphology. The new composite exhibited a tensile strength of 189 MPa, resulting in a 13 % improvement over the monolithic Al alloy. A 22% increase in yield strength and a 33% increase in wear resistance were also achieved, although the flexural and elastic moduli remained unchanged. It is proposed that these IMCs assist in load transfer from the matrix to the fibres

Immunological insights into COVID-19 in Southern Nigeria

Introduction: One of the unexpected outcomes of the COVID-19 pandemic was the relatively low levels of morbidity and mortality in Africa compared to the rest of the world. Nigeria, Africa's most populous nation, accounted for less than 0.01% of the global COVID-19 fatalities. The factors responsible for Nigeria's relatively low loss of life due to COVID-19 are unknown. Also, the correlates of protective immunity to SARS-CoV-2 and the impact of pre-existing immunity on the outcome of the COVID-19 pandemic in Africa are yet to be elucidated. Here, we evaluated the natural and vaccine-induced immune responses from vaccinated, non-vaccinated and convalescent individuals in Southern Nigeria throughout the three waves of the COVID-19 pandemic in Nigeria. We also examined the pre-existing immune responses to SARS-CoV-2 from samples collected prior to the COVID-19 pandemic. Methods: We used spike RBD and N- IgG antibody ELISA to measure binding antibody responses, SARS-CoV-2 pseudotype assay protocol expressing the spike protein of different variants (D614G, Delta, Beta, Omicron BA1) to measure neutralizing antibody responses and nucleoprotein (N) and spike (S1, S2) direct ex vivo interferon gamma (IFNγ) T cell ELISpot to measure T cell responses. Result: Our study demonstrated a similar magnitude of both binding (N-IgG (74% and 62%), S-RBD IgG (70% and 53%) and neutralizing (D614G (49% and 29%), Delta (56% and 47%), Beta (48% and 24%), Omicron BA1 (41% and 21%)) antibody responses from symptomatic and asymptomatic survivors in Nigeria. A similar magnitude was also seen among vaccinated participants. Interestingly, we revealed the presence of preexisting binding antibodies (N-IgG (60%) and S-RBD IgG (44%)) but no neutralizing antibodies from samples collected prior to the pandemic. Discussion: These findings revealed that both vaccinated, non-vaccinated and convalescent individuals in Southern Nigeria make similar magnitude of both binding and cross-reactive neutralizing antibody responses. It supported the presence of preexisting binding antibody responses among some Nigerians prior to the COVID-19 pandemic. Lastly, hybrid immunity and heterologous vaccine boosting induced the strongest binding and broadly neutralizing antibody responses compared to vaccine or infection-acquired immunity alone

Photoperiod controls vegetation phenology across Africa

Vegetation phenology is driven by environmental factors such as photoperiod, precipitation, temperature, insolation, and nutrient availability. However, across Africa, there’s ambiguity about these drivers, which can lead to uncertainty in the predictions of global warming impacts on terrestrial ecosystems and their representation in dynamic vegetation models. Using satellite data, we undertook a systematic analysis of the relationship between phenological parameters and these drivers. The analysis across different regions consistently revealed photoperiod as the dominant factor controlling the onset and end of vegetation growing season. Moreover, the results suggest that not one, but a combination of drivers control phenological events. Consequently, to enhance our predictions of climate change impacts, the role of photoperiod should be incorporated into vegetation-climate and ecosystem modelling. Furthermore, it is necessary to define clearly the responses of vegetation to interactions between a consistent photoperiod cue and inter-annual variation in other drivers, especially under a changing climate

Density and Viscosity of LiCl, LiBr, LiI and Kcl in Aqueous Methanol at 313.15K

The densities and viscosities of electrolytes are essential to understand many physicochemical processes that are taking place in the solution. In the present research, the densities and viscosities of lithium halides, LiX (X = Cl, Br, I ) and KCl in (0, 20, 40, 50, 60, 80 and 100) mass % of methanol + water at 313.15K were calculated employing experimental densities (ρ), the apparent molar volumes( ϕv) and limiting apparent molar volumes (0v) of the electrolytes. The (0v) of electrolyte offer insights into solute-solution interactions. In terms of the Jones-Dole equation for strong electrolyte solution, the experimental data of viscosity were explored. Viscosity coefficients A and B have been interpreted and discussed. The B-coefficient values in these systems increase with increase of methanol in the solvents mixtures. This implied that when the dielectric constant of the solvent decreases, so do the solvent-solvent interactions in these systems.</jats:p

Basalt fibre-reinforced high density polyethylene composite development using the twin screw extrusion process

Research data for this article: Data not available / Data will be made available on request. Supplementary data are available online at: https://www.sciencedirect.com/science/article/pii/S0142941819323797#appsec1 .Offshore renewable energy can lead the way towards sustainable energy harvesting and support the achievement of the CO2 reduction target by 2030. To achieve this goal it is necessary to decrease the manufacturing and deployment cost of the offshore devices. This paper focusses on the mechanical, chemical and microstructural assessment of a novel high density polyethylene (HDPE) reinforced with short basalt fibres for potential application as a hull material for wave energy devices. The choice of short fibres ensures the new composite can utilise existing low cost manufacturing methods for HDPE structures. In particular this study compares the properties of material with a recycled HDPE matrix with the properties of a material using a virgin HDPE matrix. The mechanical properties achieved by the novel composites exceed an improvement of ~300% in the properties of the monolithic polymer hence indicating the potential of this material, both for recycled and virgin HDPE. Furthermore, exploration in detail of the interaction fibres/matrix indicated the dynamic reaction between coupling agent and polymeric matrix showing the formation of molecular bonding perpendicular to the fibres, hence enhancing a 3D network that further increases the reinforcement abilities of the fibres.Innovate UK and EPSRC for funding this project (Innovate UK funded project 132958, funded in combination by Innovate UK and EPSRC)

Physicochemical Properties of Gum Arabic Blended with Cassava Starch and Carboxymethyl Cellulose

In this study the physicochemical properties of gum arabic blended with cassava starch and carboxymethyl cellulose was analyzed. The results obtained showed that blending of gum arabic with cassava starch and carboxymethyl cellulose led to increase in moisture content, pH and ash content, with moisture content and some ash content values lying within WHO/FAO standards of not more than 15% and 2-4% respectively for gums. The results also revealed that blending of gum arabic with carboxymethylcellulose led to increase in viscosity and swelling index while blending with cassava starch led to decrease in viscosity and swelling index. These results suggest that blending of gum arabic with carboxymethyl cellulose and/or cassava starch can be used as modification method to tailor the properties of gum Arabic to specific applications, and as cost cutting measure, as carboxymethyl cellulose and cassava starch are cheaper than gum arabic.</jats:p

Microstructural characteristics of a novel aluminium/basalt composite

Use of recycled aluminium feed-stock is limited due to its purity. Recycled aluminium can be reprocessed using just 5% of the energy required for virgin alloy production making it a resource of strategic importance. However, only half the aluminium produced/annum in the UK is of recycled origin. This limitation in uptake is due to excess iron in mixed alloy assemblies such as cars. The iron content generally forms detrimental acicular intermetallics. In this study we propose the addition of basalt fibres as reinforcement in addition to provoking a beneficial chemical reaction resulting in the transformation of the acicular intermetallics into a more desirable blocky morphology.Brunel University London, Erasmus + program and Innovate U