OBJECTIVES Despite many hypotheses, the pathophysiology of syringomyelia is still not well understood. In this report, the authors propose a hypothesis based on analysis of cerebrospinal fluid dynamics in the spine. METHODS An electric circuit model of the CSF dynamics of the spine was constructed based on a technique of computational fluid mechanics. With this model, the authors calculated h...

We study theoretically the quantum motion of a neutron in a horizontal wave-guide in the gravitational field of the Earth. The wave-guide in question is equipped with a mirror below and a rough surface absorber above. We show that such a system acts as a quantum filter, i.e. it effectively absorbs quantum states with sufficiently high transversal energy but transmits low-energy states. The stat...

In this paper, an incident angle- and polarization-insensitive metamaterial absorber is proposed for X-band applications. A unit cell of the proposed absorber has a square patch at the centre and four circular sectors are rotated around the square patch. The vertically and horizontally symmetric structure of the unit cell enables polarization-insensitivity. The circular sector of the unit cell ...

Low-frequency noise is difficult to deal with by traditional porous material due to its inherent high acoustic impedance. This study seeks to extend the effective range of sound absorption to lower frequencies by filling a low density gas, such as helium, in the porous material. Compared with conventional air-filled absorption material, the helium-filled porous material has a much reduced chara...

Wave energy has a large global resource and thus great potential to contribute low-carbon systems. This study quantifies the environmental impacts of 10MW array 28 point-absorber wave converters, by means process-based life cycle assessment (LCA). Midpoint Cumulative Energy Demand LCA results are presented over 19 impact categories, representing encompassing human health, ecosystems availabilit...

The present paper considers pitching wave energy converters (WECs) integrated in a floating platform, e.g., foundation for wind turbine. Each WEC consists of partially submerged absorber that rotates about the hinge located above still water level under influence waves. contains separated ballast tanks are used to ensure desired initial tilting angle with respect (called rest angle). same can b...

outdoor experiments on a once-through single glazed solar air heater with perforated metal absorber plate were conducted to determine the practical effect of absorber plate porosity as well as suction air flow rate on the collector thermal efficiency and its total pressure drop. three aluminum absorber plates were made perforated by drilling circular holes with different diameter/pitch ratios i...