A Detailed Investigation of the Proposed NN Serpentis Planetary System

The post-main sequence eclipsing binary NN Serpentis was recently announced as the potential host of at least two massive planetary companions. In that work, the authors put forward two potential architectures that fit the observations of the eclipsing binary with almost identical precision. In this work, we present the results of a dynamical investigation of the orbital stability of both proposed system architectures, finding that they are only stable for scenarios in which the planets are locked in mutual mean motion resonance. In the discovery work, the authors artificially fixed the orbital eccentricity of the more massive planet, NN Ser(AB) c, at 0. Here, we reanalyse the observational data on NN Serpentis without this artificial constraint, and derive a new orbital solution for the two proposed planets. We detail the results of further dynamical simulations investigating the stability of our new orbital solution, and find that allowing a small non-zero eccentricity for the outer planet renders the system unstable. We conclude that, although the original orbits proposed for the NN Serpentis planetary system prove dynamically feasible, further observations of the system are vital in order to better constrain the system's true architecture.Comment: Accepted for publication in Monthly Notices of the Royal Astronomical Society; 5 figures, 2 table

Some investigations of refractory metal systems of thermionic interest

Investigating interdiffusion of W-Ta, W-Mo, and W-Nb systems in refractory temperature rang

Laser Surface Texturing To Create Biomimetic Surface Topographies For Marine Antifouling Efficacy Testing

Biofouling is the unwanted colonisation of organisms on a living or artificial surface. Convergent evolution has led to the development of antifouling textures on many marine species. This thesis provides novel investigation into creating biomimetic antifouling surface directly onto marine grade stainless steel using laser micro machining. The investigation was split into three main research questions: (1) can laser surface texturing be used to create antifouling surfaces, and their effects on surface parameters (roughness / contact angle); (2) can biomimetic antifouling surfaces be created using laser surface texturing?; (3) can features of those successful surfaces be combined to create enhanced biomimetic antifouling surface?. All three experiments had similar methods, as laser processing was used to transfer the selected biomimetic micro-topography patterns onto marine grade stainless steel (316L). Samples were deployed in the field (Liverpool South Docks, UK) for 7 days. Abundance of biofilm was assessed using random systematic sampling. For the biomimetic surfaces, a fringe projection microscope (GFM) was used to investigate 3D scans of the surface topography of shells of bivalve and crab species, to provide bio-inspiration for the design of the surfaces created in this research. It was found that the micro-topography pattern limits the attachment of the biofilm to the surface. This thesis shows that (1) laser surface texturing can be used to create antifouling surfaces; (2) biomimetic antifouling surfaces can be created and enhance antifouling efficacy, and (3) that combining biomimetic features into multi-scale and multi-feature patterns have enhanced antifouling effects. This reinforces that biomimetic surfaces have the potential to be a non-toxic, eco-friendly antifouling technology that work directly on marine metal structures without the need for further coatings or chemicals