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8 results

  • 5 - Consonants

  • Ian R. A. MacKay, University of Ottawa
  • Book:
    Phonetics and Speech Science
    Published online:
    19 May 2023
    Print publication:
    11 May 2023, pp 100-142

  • Summary

    The word consonant means 'with a sonant' or vowel. Consonants are one of two main types of speech sounds, the other being vowels. In the production of consonants, the vocal tract is blocked, the vocal tract is seriously constricted, or the airflow is diverted through the nasal passage. The term articulation is used for the movements and adjustments required to produce an individual speech sound. Consonants are classified by (1) whether the vocal folds are vibrating, (2) where in the vocal tract articulation takes place, and (3) the manner of articulation (the type of articulation). Manners of articulation include plosives, nasals, fricatives, and approximants, the latter of which can be broken down into laterals and glides. Other manners of articulation include trills. Consonants may be produced with a secondary articulation in addition to the primary articulation.

  • 4 - Air Pressure and Aerodynamics

  • Ian R. A. MacKay, University of Ottawa
  • Book:
    Phonetics and Speech Science
    Published online:
    19 May 2023
    Print publication:
    11 May 2023, pp 81-99

  • Summary

    In the production of speech, airflow or heightened air pressure is required in order to produce the individual sounds of speech. Most usually this is achieved through the use of outgoing (egressive) air flowing from the lungs. Air pressures used in speech are generally not great, but involve a pressure differential from ambient air pressure. For the production of a small number of speech sounds, a negative air pressure is required, and for some speech sounds airflow is ingressive. Normal ambient air pressure at sea level is 101.325 kilopascals (kPa) or 14.7 pounds per square inch (psi). When air is permitted to flow unimpeded, air will flow from an area of higher pressure to an area of lesser pressure in order to equalize pressures. In speech, air may flow, causing the vocal folds to vibrate. Air may be forced to move through a constricted space such that it generates noise. Airflow may be blocked and a heightened pressure built up behind the blockage, which is then released with an explosive effect.

  • 9 - Controls of Dune Size and Spacing

  • from Part IV - Boundary Conditions for Dune Formation and Development
  • Nicholas Lancaster
  • Book:
    Geomorphology of Desert Dunes
    Published online:
    03 March 2023
    Print publication:
    23 March 2023, pp 175-185

  • Summary

    Dune height and spacing are commonly closely related. Sand particle size, airflow patterns, atmospheric boundary layer height, sand supply, and dune field geometry have all been suggested as controls on dune size and spacing, as have dune–dune interactions and pattern coarsening as part of self-organization of dune morphologic patterns.

  • The distribution of bleeding sites in idiopathic hidden arterial epistaxis

  • Z-C Lou, Z-H Lou
  • Journal:
    The Journal of Laryngology & Otology / Volume 133 / Issue 4 / April 2019
    Published online by Cambridge University Press:
    01 April 2019, pp. 309-312
    Print publication:
    April 2019
  • Objective

    To determine the frequency distribution of bleeding sites in idiopathic hidden arterial epistaxis.

    Methods

    In this retrospective cohort study, 107 patients with hidden arterial epistaxis were endoscopically examined for sites of bleeding.

    Results

    All sites of hidden arterial epistaxis were identified by endoscopic examination. Bleeding sites were identified at initial surgery in 103 patients and during the second surgery in 4. The bleeding sites included: the olfactory cleft region in 47 patients, the inferior meatus region in 29, the middle meatus region in 11, multiple bleeding sites (olfactory cleft and anterior septum) in 3, the anterior roof of the nasal cavity in 4, the nasal floor in 11 and the nasopharynx in 2. The bleeding points showed a white or red volcano-like bump in 75 patients, isolated prominent telangiectasia in 21 and mucosal ulceration in 11.

    Conclusion

    Common sites of hidden arterial epistaxis include the olfactory cleft, inferior meatus and middle meatus. However, there should be awareness of some uncommon bleeding sites (including the anterior roof of the nasal cavity, the nasal floor and the nasopharynx) and of multiple bleeding sites.

  • Analysis of indoor air quality in surgical operating roomsusing experimental and numerical investigations

  • Najla El Gharbi, Ahmed Benzaoui, Essam Eldin Khalil, Ramiz Kameel
  • Journal:
    Mechanics & Industry / Volume 13 / Issue 2 / 2012
    Published online by Cambridge University Press:
    17 April 2012, pp. 123-126
    Print publication:
    2012

  • The present work fosters experimental measurements and mathematical modelling techniquesto primarily determine the thermal and the relative humidity characteristics in theair-conditioned surgical operating room. The present work also demonstrates the effect ofthe various designs of surgical operating rooms and operational parameters on the flowpattern and temperatures characteristics. This study is a part of a more comprehensiveinvestigation of the more important factors affecting the air environments in surgicaloperating room. Measured and predicted temperatures and relative humidity profiles areshown to be in good agreement. The present paper introduces several recommendationsregarding the optimum design requirements of operating rooms to provide hygiene andcomfort environment. Low humidity affects comfort and health. The present work offersexamples of measured relative humidity profiles in an operating room in (New Kasr El-AiniTeaching Hospital – 1200 beds – Cairo University – Egypt). These experimental results werecarried out to verify the proposed numerical procedure and particularly in the vicinity ofthe supply outlets and operating table.

  • Chapter 10 - Tracheal tubes, tracheostomy tubes

  • from Section 2 - Clinical
  • Edited by Ian Calder, Adrian Pearce
  • Book:
    Core Topics in Airway Management
    Published online:
    10 January 2011
    Print publication:
    16 December 2010, pp 91-103

  • Summary

    This chapter discusses the fundamental thermodynamic concepts such as laminar flow and turbulent flow. Flow tends to be turbulent in upper airway obstruction, so gas density is influential. The functional anatomy of the upper airway can be reduced to a consideration of a collapsible segment (the pharynx) between two rigid segments (the nasopharynx and the trachea). This system behaves as a Starling resistor and airflow can become limited or completely abolished during spontaneous (negative intrathoracic pressure) breathing. Maintenance of pharyngeal airway patency is a complex neuromuscular phenomenon. In airway obstruction at the pharyngeal level, inspiratory flow may not be increased by increased inspiratory effort, but can be increased by positive pressure applied above the obstruction. The chapter describes the physics and function of a device which permitted ventilation of patients during bronchoscopy. There are a number of misconceptions regarding the operating principles of the Sanders injector.

  • Use of computational fluid dynamics to study the influence of the uncinate process on nasal airflow

  • G-X Xiong, J-M Zhan, K-J Zuo, L-W Rong, J-F Li, G Xu
  • Journal:
    The Journal of Laryngology & Otology / Volume 125 / Issue 1 / January 2011
    Published online by Cambridge University Press:
    27 September 2010, pp. 30-37
    Print publication:
    January 2011
  • Background:

    Chronic rhinosinusitis is commonly treated by functional endoscopic sinus surgery involving excision of the uncinate process and opening of the osteomeatal complex.

    Methods:

    Computational fluid dynamics were used to compare nasal airflow after two different surgical interventions which involved opening the paranasal sinuses, excising the ethmoid sinus, and excising or preserving the uncinate process, in a cadaveric head model. Cross-sectional computed tomography images were obtained before and after the interventions. Imaging data were used to prepare computer simulations, which were used to assess the airflow characteristics of the nasal cavities and paranasal sinuses during inspiration and expiration, before and after intervention.

    Results:

    Significantly larger nasal cavity airflow velocity changes were apparent following the uncinate process excising procedure. Nasal cavity airflow distribution remained relatively unchanged following the uncinate process preserving procedure. There was a significantly greater increase in airflow volume following the uncinate process excising procedure, compared with the uncinate process preserving procedure.

    Conclusion:

    Preservation of the uncinate process may significantly reduce the alteration of nasal cavity airflow dynamics occurring after functional endoscopic sinus surgery for chronic rhinosinusitis.

  • Tracking chemical plumes in constrained environments

  • R. Andrew Russell
  • Journal:
    Robotica / Volume 19 / Issue 4 / July 2001
    Published online by Cambridge University Press:
    05 July 2001, pp. 451-458

  • This paper describes an on-going project to develop robotic systems for locating chemical sources in constrained environments. There is increasing interest in applying chemical sensing to mobile robots. Locating the source of a chemical plume is seen as an important use for a chemical sensing robot. Current research tends to concentrate on source location in open and relatively obstacle free environments. Many of the applications for this technology will be areas where airflow is constrained and deflected by obstacles such as inside buildings, mines and subway tunnels. It is this kind of situation that this project aims to address.