Unsteady thin Casson-nanoliquid film flow over a porous stretching sheet

In this article, the flow of thin Casson-nanoliquid (CNL) film is examined over a porous stretching sheet with suction/injection and transverse magnetic. Appropriate similarity transformations are used to transmute the governing set of equations to a set of partial differential equations. Analytical expressions for the velocity and temperature fields are obtained by the singular perturbation technique. The non-linear film evolution equations for long time are solved by fourth-order Runge–Kutta method. It is observed that the thickness of the liquid film enhances with the nanoparticle volume fraction, Casson parameter, Hartmann number, and porosity parameter. The rate of film thinning increases for suction, whereas reverse phenomenon is found for injection. A curve $$x=X_c$$ is drawn within the CNL which divides total flow region in two parts, such that in one region, heat is transferred from sheet to the CNL film and on other zone from film to sheet

Taboos, toilets and biogas: Socio-technical pathways to acceptance of a sustainable household technology

Toilet-linked anaerobic digesters (TLADs) can provide users with a clean gaseous fuel and a fertiliser product as well as offer waste management services. Socio-cultural resistance towards domestic TLADs, due to the use of human excreta as a feedstock, is often articulated as a finite barrier to adoption. However, no research has specifically investigated the issues associated with TLADs separately from those associated with domestic digesters without toilet connections, consequently, there has been little attempt to discover what motivates users to use TLADs. Drawing on qualitative data from Nepal this paper explores how socio-cultural resistance impacts TLAD adoption and subsequent use of the biogas, and how adoption and transition pathways evolve. We argue that socio-cultural resistance is not a finite barrier to adoption and the opportunity to observe or trial a TLAD can positively influence adoption, especially amongst the older generations. Technical issues affected how TLADs were utilised more than socio-cultural norms and we discuss how socio-technical factors might co-evolve to influence sustainable adoption and use of TLADs. Caste and gender were not found to influence adoption pathways as much as the leadership or ‘risk-taking’ characteristics of specific adopters. Adoption of TLADs can occur within a year of a user first observing or trialling a TLAD; however, most users still do not use biogas for ritual cooking, despite having had a TLAD for many years. Grassroots initiatives that understand the diversity of localised socio-cultural norms will likely be imperative for successful TLAD dissemination