Engineering serendipity: high-throughput discovery of materials that resist bacterial attachment

Controlling the colonisation of materials by microorganisms is important in a wide range of industries and clinical settings. To date, the underlying mechanisms that govern the interactions of bacteria with material surfaces remain poorly understood, limiting the ab initio design and engineering of biomaterials to control bacterial attachment. Combinatorial approaches involving high-throughput screening have emerged as key tools for identifying materials to control bacterial attachment. The hundreds of different materials assessed using these methods can be carried out with the aid of computational modelling. This approach can develop an understanding of the rules used to predict bacterial attachment to surfaces of non-toxic synthetic materials. Here we outline our view on the state of this field and the challenges and opportunities in this area for the coming years

Development of a novel system for in-situ repair of aeroengine airfoil via pulsed laser ablation

A novel system for performing in-situ micro-machining of aero-engines for repair applications is proposed in this paper. Using Pulsed Laser Ablation (PLA) as material removal technique, surface cracks caused by foreign objects colliding with airfoils are removed by performing a layer-by-layer micro-machining in the area surrounding the damaged zone. Compared to conventional repair performed by micro-grinding, our invasive PLA system demonstrates a similar level of performance, evaluated from the point of view of fatigue strength in the high cycle (>107) regime. The follow-up fractographic and metallurgical analysis, indicated that although some microstructural characteristics are different between the repair methods, the incurred surface damage is limited in magnitude to a thin surface layer (<30 μm) and the influence on fatigue life is comparable. In the last section, a novel prototype system is presented which allows performing the PLA repair in-situ by use of a miniaturized laser scanning head coupled with a flexible mechanical deployment arm. The system has been successfully tested inside a Roll-Royce Trent jet engine; effectively this proves the possibility of performing in-situ laser micro-machining inside complex mechanical systems such as aero-engines, without the need for complex/expensive disassembly

Lessons learned from stock collapse and recovery of North Sea herring: a review

The collapse and recovery of North Sea herring in the latter half of the 20th century had both ecological and economic consequences. We review the effect of the collapse and investigate whether the increased understanding about the biology, ecology, and stock dynamics gained in the past three decades can aid management to prevent further collapses and improve projections of recovery. Recruitment adds the most uncertainty to estimates of future yield and the potential to reach biomass reference points within a specified time-frame. Stock–recruitment relationships must be viewed as being fluid and dependent on ecosystem change. Likewise, predation mortality changes over time. Management aimed at maximum sustainable yield (MSY) fishing mortality targets implies interannual variation in TACs, and variability in supply is therefore unavoidable. Harvest control rules, when adhered to, aid management greatly. We advocate that well-founded science can substantially contribute to management through improved confidence and increased transparency. At present, we cannot predict the effects of collapse or recovery of a single stock on the ecosystem as a whole. Moreover, as managers try to reconcile commitments to single-species MSY targets with the ecosystem-based approach, they must consider the appropriate management objectives for the North Sea ecosystem as a whole