because microaspiration of contaminated supraglottic secretions past the endotracheal tube cuff is considered to be central in the pathogenesis of pneumonia, improved design of tracheal tubes with new cuff material and shape have reduced the size and number of folds, which together with the addition of suction ports above the cuff to drain pooled subglottic secretions leads to reduced aspiratio...

The general principles underlying the acoustic performance of the avian vocal tract are examined both theoretically and experimentally. The formant resonances produced both by the total vocal tract and by the bronchial tubes are evaluated quantitatively, and their dependence upon anatomical parameters is investigated. A simplified cylindrical model for the beak is examined theoretically, and ex...

this paper presents a three-dimensional numerical investigation carried out in turbulent forced convection in a tube with helical ribs. enhancement of heat transfer using helically corrugated tubes has beenstudied experimentally by many researchers but there exist a few published numerical analyses results. the paper also introduces the results of heat transfer and friction factor data for inco...

In previous work, the authors presented a generalized parametric model of a pressure controlled valve, allowing the user to design a continuum of reed configurations, including “blown open”, “blown closed” and the “swinging door”. Though the generalized reed model behaved as expected, the quality of the produced sound was somewhat limited, likely due to the dependence of reed oscillation on the...

PURPOSE This study compared the influence of implant design (cylindrical and conical) in the load transfer on bone surrounding 13mm and 7mm length implants under simulated occlusal loading, using photoelastic analysis. METHOD Dental implants of 4mm diameter were divided into four groups, which varied in length and design: Group 1- standard (13 mm) cylindrical implant; Group 2 - standard conic...

Polymers are interesting housing materials for the fabrication of inexpensive monolithic chromatography and solid phase extraction (SPE) devices. Challenges arise when polymeric monoliths are formed in non-conical, cylindrical tubes of larger diameter due to potential monolith detachment from the housing wall resulting in loss of separation performance and mechanical stability. Here, a two-step...

in cylindrical polar coordinates is derived. This is followed by a review of the current knowledge on analytical theories and numerical treatments of nonlinear diffraction of water waves by offshore cylindrical structures. A brief discussion is made on water waves incident on a circular harbor with a narrow gap. Special emphasis is given to the resonance phenomenon associated with this problem....

INTRODUCTION Spontaneous sedimentation is an important procedure for stool examination. A modification of this technique using conical tubes was performed and evaluated. METHODS Fifty fecal samples were processed in sedimentation glass and in polypropylene conical tubes. Another 50 samples were used for quantitative evaluation of protozoan cysts. RESULTS Although no significant differences ...

The use of 3D model to simulation dentistry problems with finite element method has been reported. The purpose of this study was to evaluate the stress distribution in the cortical bone under different shape of dental implants in cantilever loading. The models were constructed with commercial conical and cylindrical implants of 4.3 mm diameter and 11mm length using ANSYS program. All materials ...