The Experts below are selected from a list of 180 Experts worldwide ranked by ideXlab platform
Peter A. Cistulli - One of the best experts on this subject based on the ideXlab platform.
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Three-dimensional assessment of anatomical balance and oral appliance treatment outcome in obstructive sleep apnoea
Sleep and Breathing, 2016Co-Authors: Kate Sutherland, Andrew S. L. Chan, Peter A. CistulliAbstract:Purpose Mandibular advancement splints (MAS) are an effective treatment for obstructive sleep apnoea (OSA). However, MAS are not equally efficacious across all patients and the reasons are not well understood. Craniofacial and upper airway structure individually influence MAS response. We aimed to assess anatomical balance, defined as the ratio of upper airway soft tissue (ST) Volume to maxillomandibular Enclosure Volume, between MAS treatment responders and non-responders. Methods OSA patients (apnoea-hypopnea index (AHI) >10 h^−1) were recruited for MAS treatment. Magnetic resonance imaging of the upper airway was performed during wakefulness without and with MAS in situ. Images were processed for Volumetric analysis of upper airway soft tissues (tongue, soft palate, paraphayrngeal fat pads and lateral pharyngeal walls) and three-dimensional cephalometry to acquire intra-mandibular space area (IMA) and total maxillomandibular (Mm) Volume. Anatomical balance ratios were compared between MAS treatment responders (AHI
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Three-dimensional assessment of anatomical balance and oral appliance treatment outcome in obstructive sleep apnoea.
Sleep & breathing = Schlaf & Atmung, 2016Co-Authors: Kate Sutherland, Andrew S. L. Chan, Peter A. CistulliAbstract:Purpose Mandibular advancement splints (MAS) are an effective treatment for obstructive sleep apnoea (OSA). However, MAS are not equally efficacious across all patients and the reasons are not well understood. Craniofacial and upper airway structure individually influence MAS response. We aimed to assess anatomical balance, defined as the ratio of upper airway soft tissue (ST) Volume to maxillomandibular Enclosure Volume, between MAS treatment responders and non-responders.
Vladimir Molkov - One of the best experts on this subject based on the ideXlab platform.
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Pressure peaking phenomenon for indoor hydrogen releases
International Journal of Hydrogen Energy, 2018Co-Authors: Sile Brennan, Vladimir MolkovAbstract:Abstract The pressure peaking phenomenon can be observed when hydrogen is released in Enclosures with vent(s). The unforeseen physical phenomena of pressure peaking has been described and explained. This phenomenon occurs for hydrogen releases in Enclosures where the vent(s), Volume, and leak rate are such that there will be no air ingress to the Enclosure. Pressure peaking describes the physical phenomenon of a peak in the pressure transient during such a release for some release conditions in a vented Enclosure. This phenomenon is pronounced only for gases lighter than air, e.g. hydrogen and helium. For particular release flow rates and vent sizes the peak can be an order of magnitude higher compared to the steady-state overpressure that is reached when the Enclosure is fully filled with hydrogen over time. This finding is relevant to all hydrogen applications indoors from a fuel cell in an Enclosure or laboratory scale storage up to a forklift in a warehouse. The peak magnitude depends on the release flow rate, hydrogen inventory, Enclosure Volume and the ventilation area, and potentially can exceed the maximum pressure which the Enclosure can withstand. A look up nomogram for applicability of the developed theory that is based on vent area and leak rate has been created for sustained releases. Experimental evidence of the phenomena is described. Reduced analytical equations are presented for the case of a constant flow rate release, and the associated nomogram is presented for use by hydrogen safety engineers and regulators.
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Pressure peaking phenomenon: Model validation against unignited release and jet fire experiments
International Journal of Hydrogen Energy, 2018Co-Authors: Dmitriy Makarov, Volodymyr Shentsov, M. Kuznetsov, Vladimir MolkovAbstract:Abstract The aim of this study is validation of pressure peaking phenomenon models for unignited and ignited releases of hydrogen in Enclosures with limited ventilation, e.g. residential garages. The existence of “unexpected” peak in the pressure transient during release of a lighter than air gas in a vented Enclosure was observed by Brennan et al. (2010) by carrying out theoretical and numerical research. The amplitude and duration of this pressure peak vary depending on the Enclosure Volume, vent size and leak flow rate. The peak can significantly exceed the steady-state overpressure, which is reached when the Enclosure is fully occupied by leaking with a constant rate gas. The pressure peaking phenomenon can jeopardise a civil structure integrity in the case of accident if it is ignored at the design stage of hydrogen-powered vehicles. This could cause serious life safety and property protection issues that requires development of prevention and mitigation strategies and innovative safety engineering solutions. The experimental validation of the phenomenon was absent up to this work. The previous model for unignited release and developed in this study model for ignited release (jet fire) have been validated against experiments performed in a vented Enclosure of 1 m3 Volume with three different gases: air, helium, and hydrogen. The model for unignited release reproduces closely the experimental pressure peak and the pressure dynamics within the Enclosure. The model for ignited release reproduces the pressure peak with acceptable engineering accuracy, and the simulation of pressure dynamics after the peak requires the increase of the discharge coefficient due to the change of vent flow from heavier air at the start to lighter hot combustion products afterwards and ultimately hydrogen. The methodology to calculate the pressure peaking phenomenon in two steps is described in detail. Examples of pressure peaking phenomenon calculation for typical hydrogen applications are presented. The phenomenon is relevant to most of indoor applications, when release of lighter than air gas is possible in an Enclosure with limited ventilation. It must be considered when performing safety engineering design of inherently safer hydrogen systems and infrastructure.
Kate Sutherland - One of the best experts on this subject based on the ideXlab platform.
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Three-dimensional assessment of anatomical balance and oral appliance treatment outcome in obstructive sleep apnoea
Sleep and Breathing, 2016Co-Authors: Kate Sutherland, Andrew S. L. Chan, Peter A. CistulliAbstract:Purpose Mandibular advancement splints (MAS) are an effective treatment for obstructive sleep apnoea (OSA). However, MAS are not equally efficacious across all patients and the reasons are not well understood. Craniofacial and upper airway structure individually influence MAS response. We aimed to assess anatomical balance, defined as the ratio of upper airway soft tissue (ST) Volume to maxillomandibular Enclosure Volume, between MAS treatment responders and non-responders. Methods OSA patients (apnoea-hypopnea index (AHI) >10 h^−1) were recruited for MAS treatment. Magnetic resonance imaging of the upper airway was performed during wakefulness without and with MAS in situ. Images were processed for Volumetric analysis of upper airway soft tissues (tongue, soft palate, paraphayrngeal fat pads and lateral pharyngeal walls) and three-dimensional cephalometry to acquire intra-mandibular space area (IMA) and total maxillomandibular (Mm) Volume. Anatomical balance ratios were compared between MAS treatment responders (AHI
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Three-dimensional assessment of anatomical balance and oral appliance treatment outcome in obstructive sleep apnoea.
Sleep & breathing = Schlaf & Atmung, 2016Co-Authors: Kate Sutherland, Andrew S. L. Chan, Peter A. CistulliAbstract:Purpose Mandibular advancement splints (MAS) are an effective treatment for obstructive sleep apnoea (OSA). However, MAS are not equally efficacious across all patients and the reasons are not well understood. Craniofacial and upper airway structure individually influence MAS response. We aimed to assess anatomical balance, defined as the ratio of upper airway soft tissue (ST) Volume to maxillomandibular Enclosure Volume, between MAS treatment responders and non-responders.
Andrew S. L. Chan - One of the best experts on this subject based on the ideXlab platform.
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Three-dimensional assessment of anatomical balance and oral appliance treatment outcome in obstructive sleep apnoea
Sleep and Breathing, 2016Co-Authors: Kate Sutherland, Andrew S. L. Chan, Peter A. CistulliAbstract:Purpose Mandibular advancement splints (MAS) are an effective treatment for obstructive sleep apnoea (OSA). However, MAS are not equally efficacious across all patients and the reasons are not well understood. Craniofacial and upper airway structure individually influence MAS response. We aimed to assess anatomical balance, defined as the ratio of upper airway soft tissue (ST) Volume to maxillomandibular Enclosure Volume, between MAS treatment responders and non-responders. Methods OSA patients (apnoea-hypopnea index (AHI) >10 h^−1) were recruited for MAS treatment. Magnetic resonance imaging of the upper airway was performed during wakefulness without and with MAS in situ. Images were processed for Volumetric analysis of upper airway soft tissues (tongue, soft palate, paraphayrngeal fat pads and lateral pharyngeal walls) and three-dimensional cephalometry to acquire intra-mandibular space area (IMA) and total maxillomandibular (Mm) Volume. Anatomical balance ratios were compared between MAS treatment responders (AHI
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Three-dimensional assessment of anatomical balance and oral appliance treatment outcome in obstructive sleep apnoea.
Sleep & breathing = Schlaf & Atmung, 2016Co-Authors: Kate Sutherland, Andrew S. L. Chan, Peter A. CistulliAbstract:Purpose Mandibular advancement splints (MAS) are an effective treatment for obstructive sleep apnoea (OSA). However, MAS are not equally efficacious across all patients and the reasons are not well understood. Craniofacial and upper airway structure individually influence MAS response. We aimed to assess anatomical balance, defined as the ratio of upper airway soft tissue (ST) Volume to maxillomandibular Enclosure Volume, between MAS treatment responders and non-responders.
Knut Vaagsaether - One of the best experts on this subject based on the ideXlab platform.
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Pressure peaking phenomena: Unignited hydrogen releases in confined spaces – Large-scale experiments
International Journal of Hydrogen Energy, 2020Co-Authors: Agnieszka Weronika Lach, André Vagner Gaathaug, Knut VaagsaetherAbstract:Abstract The aim of this study was to validate a model for predicting overpressure arising from accidental hydrogen releases in areas with limited ventilation. Experiments were performed in a large-scale setup that included a steel-reinforced container of Volume 14.9 m3 and variable ventilation areas and mass flow rates. The pressure peaking phenomenon, characterized as transient overpressure with a characteristic peak in a vented Enclosure, was observed during all the experiments. The model description presented the relationship between the ventilation area, mass flow rate, Enclosure Volume, and discharge coefficient. The experimental results were compared with two prediction models representing a perfect mix and the real mix. The perfect mix assumed that all the released hydrogen was well stirred inside the Enclosure during the releases. The real mix prediction s used the hydrogen concentration and temperature data measured during experiments. The prediction results with both perfect mix and real mix showed possible hazards during unignited hydrogen releases.