Dielectric elastomer stack actuator-based autofocus fluid lens

Extremely small cameras and many cell phones simply do not have enough room to allow users to move a rigid lens the distance required for a varying range of focal lengths. An adaptive liquid lens, however, enables small cameras to focus without needing extra room. An autofocus liquid lens provides several advantages over a traditional lens in terms of efficiency, cost, compactness, and flexibility. But one of the main challenges in these lenses is a high driving voltage requirement of around at least 1.8 kV. In this paper, we propose a new design of a liquid lens based on a dielectric elastomer stack actuator (DESA), which significantly overcomes the aforementioned existing problem. The lens consists of a frame (a thin DESA membrane with a hole in the middle), silicon oil, and water. A voltage range is applied on the membrane in order to change the hole dimension. Due to change of hole dimension, a change in meniscus occurs that changes the focal length of the lens. In this research work, various experimental results are achieved by configuring two DESA with different active areas. Depending on the active area of the membrane, the length of the laser beam on the plane varies from 6 to 35 mm, and the driving voltage is in the range of 50–750 V

Subarachnoid Hemorrhage Revealing a Spinal Dural Arterio-Venous Fistula: About a Rare Complication

Teaching Point: Subarachnoid hemorrhage is a rare complication of spinal dural arteriovenous fistulas (dAVF) with very characteristic imaging features, knowledge of which is crucial for positive diagnosis and rapid management

Mitigation and screening for environmental assessment

This article considers how, as a matter of law and policy, mitigation measures should be taken into account in determining whether a project will have significant environmental effects and therefore be subject to assessment under the EU Environmental Impact Assessment (EIA) Directive. This is not straightforward: it is problematic to distinguish clearly between an activity and the measures proposed to minimise or mitigate for the adverse consequences of the activity. The issue is a salient one in impact assessment law, but under-explored in the literature and handled with some difficulty by the courts. I argue that there is an unnecessarily and undesirably narrow approach currently taken under the EIA Directive, which could be improved upon by taking a more adaptive approach; alternatively a heightened standard of review of ‘significance’, and within this of the scope for mitigation measures to bring projects beneath the significance threshold, may also be desirable

Pál Paricsy (Editor), Studies on modern black African literature.

Hous Maurice. Pál Paricsy (Editor), Studies on modern black African literature.. In: Journal de la Société des Africanistes, 1972, tome 42, fascicule 2. p. 237

Pál Paricsy (Editor), Studies on modern black African literature.

Hous Maurice. Pál Paricsy (Editor), Studies on modern black African literature.. In: Journal de la Société des Africanistes, 1972, tome 42, fascicule 2. p. 237