Thesis by publication. 
Chapters 2, 3, 4, 5, published by Elsevier. Elsevier has a policy of allowing published articles to remain in theses.  https://www.elsevier.com/about/policies/copyright/permissions (click on Can I include/use my article in my thesis/dissertation)
Chapter 6 - permitted. https://www.springer.com/gp/rights-permissions/obtaining-permissions/882 "Authors have the right to reuse their article’s Version of Record, in whole or in part, in their own thesis. Additionally, they may reproduce and make available their thesis, including Springer Nature content, as required by their awarding academic institution. Authors must properly cite the published article in their thesis according to current citation standards." Author included citation on page 82.

Signature on PDF removed and full-text attachment replaced. LM 13/07/20