abstract background: transtracheal jet ventilation is an alternative ventilatory approach in airway surgery. the purpose of this study was to compare respiratory efficacy of percutaneous transtracheal with endotracheal, low frequency jet ventilation during microlaryngeal surgery. methods: ninety asa class i-ii patients aged between 16 and 70 years undergoing elective microlaryngeal surgery were...

A liquid jet can stably bounce off a sufficiently soft gel by following the contour of the dimple created upon impact. This new phenomenon is insensitive to the wetting properties of the gels and was observed for different liquids over a wide range of surface tensions, γ=24-72  mN/m. In contrast, other jet rebound phenomena are typically sensitive to γ: only a high γ jet rebounds off a hard sol...

The effect of viscosity on jet formation for bubbles collapsing near solid boundaries is studied numerically. A numerical technique is presented which allows the Navier-Stokes equations with free-surface boundary conditions to be solved accurately and efficiently. Good agreement is obtained between experimental data and numerical simulations for the collapse of large bubbles. However, the bubbl...

Flip buckets are terminal spillway elements, generating free jets for energy dissipation. Deflectors are an alternative to flip buckets with constructional ease yet of similar hydraulic features. A first experimental study published at the 33 IAHR Congress, Vancouver, investigated deflectorgenerated jets in terms of their air concentration characteristics. For jet impact onto a movable bed, the...

A circular disc hitting a water surface creates an impact crater which after collapse leads to a vigorous jet. Upon impact an axisymmetric air cavity forms and eventually pinches off in a single point halfway down the cavity. Two fast sharp-pointed jets are observed shooting up- and downwards from the closure location, which by then has turned into a stagnation point surrounded by a locally hyp...

The rapid growth of the aviation sector around the globe has witnessed an overwhelming impact on fossil fuel resources. With the implementation of stricter environmental laws over emissions by conventional jet fuels, growing demand for research on alternative fuels has become imperative. One-hundred percent Synthetic Paraffinic Kerosene (SPK) and Fully Formulated Synthetic Jet Fuel have surface...

Abstract Splashes of high-temperature melt spreading over a water pool bottom can be reason for the formation zone where melt, and steam are mixed, providing conditions powerful explosions. The paper considers splashes arising from impact jet on surface melt. Numerical simulations performed in 3D formulation, using VOF method an improved phase change model. evolution following is demonstrated, ...

Collisions of bubble jets have been experimentally studied in normal gravity conditions. The experimental setup, designed for a future use in a low gravity environment, allows the control of the impact angle between jets, bubble size and velocity. Individual bubble properties and the whole jet structure are analyzed from the images recorded. We present results on the role played by the impact a...

As functional (total care) products emerge in the jet engine industry, the need for product life-cycle models capable of definition and evaluation of life cycle properties increases, since functional products (FP) includes both hardware and service. Recent life-cycle models are intended for hardware products and mostly handle design and manufacturing knowledge. The aim of this article is to pre...