Exploding Foil Initiator (EFI) flyer layer velocities measured down the barrel of an EFI are presented. Flyer velocity was shown to be proportional to supply voltage and of a similar order to other studies previously conducted. Bridge volume ejection was shown to be proportional to capacitor voltage. Current density increased with respect to capacitor voltage up to a point of saturation between 2400 V and 3000 V (evidenced electrically). Beyond the saturation voltage, high voltages demonstrated sustained energy delivery at a reduced current. This work indicates that control of active bridge volume or electrical supply signal may enable more closely controlled EFI flyer layer ejection behavior, and it demonstrates the relevance of using current per active bridge (specific current) as a metric to describe EFI electrical performance with relevance to dynamic response of the EFI. The impulse delivered by an EFI can be modulated via manipulation of the firing circuit input signal giving rise to system behavior variation.

To observe excimer laser machining through thin liquid films and the effects thereof on debris control, equipment was designed to contain a small control volume that can be supplied with a laminar thin film of DI water to flow over the workpiece. Using the same equipment, comparison with non-liquid ablation was possible. Reliable calculations of the debris size and density with respect to the distance from the centre of the shot, as well as the identification of modal trends in the dispersion of the debris were obtained from analysis of microscope images with graphical analysis software. The results suggest that the positional debris deposition of samples machined in ambient air show modal tendency reliant on the feature shape machined and according to species size. This is proposed to be due to the interaction of multiple shockwaves at the extent of ablation plumes generated at geometry specific locations in the feature. Debris is deposited where the shockwaves collide. Large debris did not typically travel much further than the boundary of the machined feature, whereas intermediate debris was found in radial streaks at a normal to the circular feature’s perimeter. Laminar flows of liquid have shown potential to modify the end position and typical size of the debris produced, as well as increased homogeneity of deposition density. The use of immersion has reduced typical range by 17%, and the deposition within the boundary of the ablation plume has a comparatively even population density with respect to the sample machined in ambient air. Outside the ablation plume extents, evidence of positional control of deposited debris species by laminar flow DI water immersion is shown by debris deposition in rippled flow line patterns for both circular and square features, indicating the action of transport by fluid flow. A typical increase in debris size by an order of magnitude when using DI water as an immersing liquid has been measured, a result that is in line with a colloidal interaction response

Spotted wing drosophila, Drosophila suzukii, is a serious invasive pest impacting the production of multiple fruit crops, including soft and stone fruits such as strawberries, raspberries and cherries. Effective control is challenging and reliant on integrated pest management which includes the use of an ever decreasing number of approved insecticides. New means to reduce the impact of this pest that can be integrated into control strategies are urgently required. In many production regions, including the UK, soft fruit are typically grown inside tunnels clad with polyethylene based materials. These can be modified to filter specific wavebands of light. We investigated whether targeted spectral modifications to cladding materials that disrupt insect vision could reduce the incidence of D. suzukii. We present a novel approach that starts from a neuroscientific investigation of insect sensory systems and ends with infield testing of new cladding materials inspired by the biological data. We show D. suzukii are predominantly sensitive to wavelengths below 405 nm (ultraviolet) and above 565 nm (orange & red) and that targeted blocking of lower wavebands (up to 430 nm) using light restricting materials reduces pest populations up to 73% in field trials.

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• This is an article from the journal, Proceedings of the IMechE, Part B: Abstract: Until now, progress in laser ablation micromachining has been significantly limited with respect to feature miniaturization and output yield by ablation-generated debris. Gasjetting techniques have proven to be inadequate and vacuum environments are unwieldy in an industrial setting. To this end, a controlled geometry for both the optical interfaces of a flowing liquid film can be provided by a closed flowing thick film filtered water immersion technique. This ensures repeatable machining conditions and allows control of liquid flow velocity. To investigate the impact of this technique on etch rate, bisphenol A polycarbonate samples have been machined using KrF excimer laser radiation passing through a medium of filtered water flowing at a number of flow velocities that are controllable by modifying liquid flowrate. A mean increase in etch rate of 8.5 per cent when using a turbulent flow velocity regime immersed ablation over ablation in ambient air was recorded. However, use of laminar flow velocities resulted in a mean loss of 26.6 per cent in etch rate compared to ablation in ambient air. Plotting the recorded etch rate achieved with respect to flow velocity gives support for previously proposed flow-plume interactions: the primary cause of a 37 per cent variance in etch rate over a 72 per cent change in laminar flow velocity was a shift in the ratio between the refresh rate of liquid volume over the feature and laser repetition rate. The small variance of etch rate achieved by modification of turbulent regime flow velocity indicates that laser etching provided the dominating contribution to the total etch rate measured. This work demonstrates that this technique developed for ablation debris control does not reduce the efficiency of laser etching with respect to that achieved with established gas media laser ablation machining. Therefore, this process shows great promise for industrial implementation development.