Graphene nanosheet-sandwiched platinum nanoparticles deposited on a graphite pencil electrode as an ultrasensitive sensor for dopamine.

An ultra-sensitive sensor of dopamine is introduced. The sensor is constructed by encapsulating platinum nanoparticles (PtNPs) between reduced graphene oxide (GR) nanosheets. The sandwiched PtNPs between GR layers acted as a spacer to prevent aggregation and provided a fine connection between the GR nanosheets to provide fast charge transfer.

New Lightweight Cement Formulation for Shallow Oil and Gas Wells.

The use of lightweight pozzolanic aggregates as partial replacement of cement results in low-density cement systems. Such systems ensure effective zonal isolation in zones where low equivalent circulating densities are required. However, low pozzolanic materials, such as fly ash and ground granulated blast furnace slag (GGBFS), have poor early-age strength development and long set times, especially when used in high volume, that is, exceeding 50% by weight of cement.