The effect of sodium on refractory phase formation in a model Calcium Aluminate Cement-bonded refractory was investigated from 700°C to 1500°C. Sodium reacts with a-alumina to form sodium b-alumina (b-Al 2 O 3 ) via the intermediate NaAlO 2 . Formation of b-Al 2 O 3 disrupts the reaction path of calcia with alumina, delaying crystallization of calcium hexaluminate, CaOÁ6Al 2 O 3 , from 1350°C to 1500°C. b-Al 2 O 3 is also shown to reduce Young's modulus and delay sintering. The presence of NaAlO 2 and b-Al 2 O 3 result in an increase in internal friction. Increased linear expansion of up to 47% is observed when 1 wt% Na is added. The expansion is shown to scale with the amount of dopant with only 0.3 wt% Na leading to an additional 31% linear expansion. On cooling, the presence of bAl 2 O 3 can be demonstrated by a peak in internal friction between 1200°C and 1000°C which could be caused by Na + ion hopping along the spinel-like planes.

Background Global plastic production has increased exponentially since the 1960s, with more than 6300 million metric tons of plastic waste generated to date. Studies have found a range of human health outcomes associated with exposure to plastic chemicals. However, only a fraction of plastic chemicals used have been studied in vivo, and then often in animals, for acute toxicological effects. With many questions still unanswered about how long-term exposure to plastic impacts human health, there is an urgent need to map human in vivo research conducted to date, casting a broad net by searching terms for a comprehensive suite of plastic chemical exposures and the widest range of health domains. Methods This protocol describes a scoping review that will follow the recommended framework outlined in the 2017 Guidance for the Conduct of Joanna Briggs Institute (JBI) Scoping Reviews, to be reported in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) Checklist. A literature search of primary clinical studies in English from 1960 onwards will be conducted in MEDLINE (Ovid) and EMBASE (Ovid) databases. References eligible for inclusion will be identified through a quality-controlled, multi-level screening process. Extracted data will be presented in diagrammatic and tabular form, with a narrative summary addressing the review questions. Discussion This scoping review will comprehensively map the primary research undertaken to date on plastic exposure and human health. Secondary outputs will include extensive databases on plastic chemicals and human health outcomes/impacts. Systematic review registration Open Science Framework (OSF)-Standard Pre-Data Collection Registration, https://archive.org/details/osf-registrations-gbxps-v1, https://doi.org/10.17605/OSF.IO/GBXPS

Background: Global plastic production has increased exponentially since the 1960s, with more than 6300 million metric tons of plastic waste generated to date. Studies have found a range of human health impacts associated with exposure to plastic chemicals. However, only a fraction of plastic chemicals used have been studied in vivo, and then often in animals, for acute toxicological effects. With many questions still unanswered about how long-term exposure to plastic impacts human health, there is an urgent need to map human in vivo research conducted to date, casting a broad net by searching terms for a comprehensive suite of plastic chemical exposures and the widest range of health domains. Methods: This protocol describes a scoping review that will follow the recommended framework outlined in 2017 Guidance for the Conduct of Joanna Briggs Institute (JBI) Scoping Reviews, to be reported in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) Checklist. A literature search of primary clinical studies in English from 1960 onwards will be conducted in MEDLINE (Ovid) and EMBASE (Ovid) databases. References eligible for inclusion will be identified through a quality-controlled, multi-level screening process. Extracted data will be presented in diagrammatic and tabular form, with a narrative summary addressing the review questions. Discussion: This scoping review will comprehensively map the primary research undertaken to date on plastic exposure and human health. Secondary outputs will include extensive databases on plastic chemicals and human health outcomes/impacts.

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