Four-handed dentistry with high-volume suction and a saliva ejector are essential mitigating fact... more Four-handed dentistry with high-volume suction and a saliva ejector are essential mitigating factors during AGPs.
AimTo calculate fallow time (FT) required following dental aerosol generating procedures (AGPs) i... more AimTo calculate fallow time (FT) required following dental aerosol generating procedures (AGPs) in both a dental hospital (mechanically ventilated) and primary care (non-mechanically ventilated). Secondary outcomes were to identify spread and persistence of aerosol in open clinics compared to closed surgeries (mechanically ventilated environment), and identify if extra-oral scavenging (EOS) reduces production of aerosol and FT.MethodsIn vitro simulation of fast handpiece (FHP) cavity preparations using a manikin was conducted in a mechanically and non-mechanically ventilated environment using Optical Particle Sizer™ and NanoScan™ at baseline, during the procedure and fallow period.ResultsAGPs carried out in the non-mechanically, non-ventilated environment failed to achieve baseline particle levels after one hour. In contrast, when windows were opened after AGP, there was an immediate reduction in all particle sizes.In mechanically ventilated environments the baseline levels of parti...
... Faidon Christakopoulos Corresponding Author Contact Information , a , E-mail The Correspondin... more ... Faidon Christakopoulos Corresponding Author Contact Information , a , E-mail The Corresponding Author , Dominic Jones a , E-mail The Corresponding Author and Jens-Dominik Müller a , E-mail The Corresponding Author. ...
Introduction This study was conducted in light of the SARS-CoV-2 pandemic, which brought UK denti... more Introduction This study was conducted in light of the SARS-CoV-2 pandemic, which brought UK dentistry to a standstill. The market has seen a recent influx of unproven extraoral scavengers (EOSs), which claim to reduce the risk of particulate spread.Aims To investigate the efficacy of a commercially available EOS device on contamination reduction during dental aerosol generating procedures (AGPs). The secondary aim was to investigate differences between open and closed dental operatories.Method Dental procedures were simulated on a dental manikin using citric acid (10%) added to the water lines with universal indicating paper (UIP) placed in strategic locations in the operatory, on the clinician and assistant. Chromatic change related to settling of splatter containing citric acid on the UIP was analysed to calculate percentage intensity of splatter contamination.Results EOSs resulted in 20% reduction in frequency and 75% reduction in mean intensity of contamination of operatory site...
Introduction: Transmission of SARS-Cov-2 through aerosol has been implicated particularly in the ... more Introduction: Transmission of SARS-Cov-2 through aerosol has been implicated particularly in the presence of highly concentrated aerosols in enclosed environments. It is accepted that aerosols are produced during a range of dental procedures, posing potential risks to both dental practitioners and patients. There has been little agreement concerning aerosol transmission associated with orthodontics and associated mitigation. Methods: Orthodontic procedures were simulated in a closed side-surgery using a dental manikin on an acrylic model using composite-based adhesive. Adhesive removal representing debonding was undertaken using a 1:1 contra-angle handpiece and fast hand-piece with variation in air and water flow. The removal of acid etch was also simulated with use of combined 3-in-1 air water syringe to remove etch. An optical particle scanner and a spectrometer particle scanner were both to assess particulate matter ranging from 'very small' (0.08 - 0.26 um) to large (2.7...
Volume 1: Compressors, Fans and Pumps; Turbines; Heat Transfer; Combustion, Fuels and Emissions
In the present work, transient liquid crystal thermography (LCT) has been used for capturing the ... more In the present work, transient liquid crystal thermography (LCT) has been used for capturing the temperature field as well as the local heat transfer distribution inside a rectangular duct. Experiments have been carried out in an open loop airflow system at a Reynolds number (based on the channel hydraulic diameter) of 58850 and for rib height to channel hydraulic diameter ratio of 0.125. This investigation emphases headed for assessing the potential impact of design parameters such as chamfering angle and rib pitch to height ratio of the trapezium ribbed rectangular duct on the thermo-hydraulic performances, which forms the basis of analysis while using response surface methodology (RSM). The chamfering angle has been varied from 0 to 20° in a step of 5°, while the rib pitch to height ratio is varied from 8 to 12 in a step of 2. The quadratic model generated by RSM is used to predict the optimal performance parameters. The results show that different geometrical parameters have to ...
In the final phase before submission to a journal, we have prepared an internal draft report for ... more In the final phase before submission to a journal, we have prepared an internal draft report for a limited distribution. This is not a final document. Updates and corrections are likely to be included prior to publication. In recognition of this, we would appreciate any comments or critics you might have on our research or this document. We welcome any opportunity to improve or clarify any part of our discussion, or to expand upon points of particular interest.
An unstructured grid generation method based o s the Delaunay triangulation is presented that is ... more An unstructured grid generation method based o s the Delaunay triangulation is presented that is capable of generating stretched layers along surface lines while retaining strong control over maximum angles. The method requires only minimum user input in form of a set of boundary nodes, the character of each boundary, the thickness of the stretched layer and the maximum aspect ratio desired. Upper and lower angular bounds and an upper bound in surface variation between neighboring cells are proven. 2 Generation of the background mesh The Delaunay triangulation of all boundary nodes is computed as an initial triangulation to begin the node gen
Solution adaptive mesh refinement using adjoint error analysis. Jens-Dominik Mueller, Michael B G... more Solution adaptive mesh refinement using adjoint error analysis. Jens-Dominik Mueller, Michael B Giles AIAA Computational Fluid Dynamics Conference, 15 th, Anaheim, CA, 2001. A solution adaptive mesh refinement method for unstructured meshes is presented. ...
A comparison of the treatment of hanging nodes for hybrid grid refinement. Jens-Dominik Mueller, ... more A comparison of the treatment of hanging nodes for hybrid grid refinement. Jens-Dominik Mueller, Thilo Schoenfeld, Michael Rudgyard AIAA, Computational Fluid Dynamics Conference, 13 th, Snowmass Village, CO, 1997. We ...
Four-handed dentistry with high-volume suction and a saliva ejector are essential mitigating fact... more Four-handed dentistry with high-volume suction and a saliva ejector are essential mitigating factors during AGPs.
AimTo calculate fallow time (FT) required following dental aerosol generating procedures (AGPs) i... more AimTo calculate fallow time (FT) required following dental aerosol generating procedures (AGPs) in both a dental hospital (mechanically ventilated) and primary care (non-mechanically ventilated). Secondary outcomes were to identify spread and persistence of aerosol in open clinics compared to closed surgeries (mechanically ventilated environment), and identify if extra-oral scavenging (EOS) reduces production of aerosol and FT.MethodsIn vitro simulation of fast handpiece (FHP) cavity preparations using a manikin was conducted in a mechanically and non-mechanically ventilated environment using Optical Particle Sizer™ and NanoScan™ at baseline, during the procedure and fallow period.ResultsAGPs carried out in the non-mechanically, non-ventilated environment failed to achieve baseline particle levels after one hour. In contrast, when windows were opened after AGP, there was an immediate reduction in all particle sizes.In mechanically ventilated environments the baseline levels of parti...
... Faidon Christakopoulos Corresponding Author Contact Information , a , E-mail The Correspondin... more ... Faidon Christakopoulos Corresponding Author Contact Information , a , E-mail The Corresponding Author , Dominic Jones a , E-mail The Corresponding Author and Jens-Dominik Müller a , E-mail The Corresponding Author. ...
Introduction This study was conducted in light of the SARS-CoV-2 pandemic, which brought UK denti... more Introduction This study was conducted in light of the SARS-CoV-2 pandemic, which brought UK dentistry to a standstill. The market has seen a recent influx of unproven extraoral scavengers (EOSs), which claim to reduce the risk of particulate spread.Aims To investigate the efficacy of a commercially available EOS device on contamination reduction during dental aerosol generating procedures (AGPs). The secondary aim was to investigate differences between open and closed dental operatories.Method Dental procedures were simulated on a dental manikin using citric acid (10%) added to the water lines with universal indicating paper (UIP) placed in strategic locations in the operatory, on the clinician and assistant. Chromatic change related to settling of splatter containing citric acid on the UIP was analysed to calculate percentage intensity of splatter contamination.Results EOSs resulted in 20% reduction in frequency and 75% reduction in mean intensity of contamination of operatory site...
Introduction: Transmission of SARS-Cov-2 through aerosol has been implicated particularly in the ... more Introduction: Transmission of SARS-Cov-2 through aerosol has been implicated particularly in the presence of highly concentrated aerosols in enclosed environments. It is accepted that aerosols are produced during a range of dental procedures, posing potential risks to both dental practitioners and patients. There has been little agreement concerning aerosol transmission associated with orthodontics and associated mitigation. Methods: Orthodontic procedures were simulated in a closed side-surgery using a dental manikin on an acrylic model using composite-based adhesive. Adhesive removal representing debonding was undertaken using a 1:1 contra-angle handpiece and fast hand-piece with variation in air and water flow. The removal of acid etch was also simulated with use of combined 3-in-1 air water syringe to remove etch. An optical particle scanner and a spectrometer particle scanner were both to assess particulate matter ranging from 'very small' (0.08 - 0.26 um) to large (2.7...
Volume 1: Compressors, Fans and Pumps; Turbines; Heat Transfer; Combustion, Fuels and Emissions
In the present work, transient liquid crystal thermography (LCT) has been used for capturing the ... more In the present work, transient liquid crystal thermography (LCT) has been used for capturing the temperature field as well as the local heat transfer distribution inside a rectangular duct. Experiments have been carried out in an open loop airflow system at a Reynolds number (based on the channel hydraulic diameter) of 58850 and for rib height to channel hydraulic diameter ratio of 0.125. This investigation emphases headed for assessing the potential impact of design parameters such as chamfering angle and rib pitch to height ratio of the trapezium ribbed rectangular duct on the thermo-hydraulic performances, which forms the basis of analysis while using response surface methodology (RSM). The chamfering angle has been varied from 0 to 20° in a step of 5°, while the rib pitch to height ratio is varied from 8 to 12 in a step of 2. The quadratic model generated by RSM is used to predict the optimal performance parameters. The results show that different geometrical parameters have to ...
In the final phase before submission to a journal, we have prepared an internal draft report for ... more In the final phase before submission to a journal, we have prepared an internal draft report for a limited distribution. This is not a final document. Updates and corrections are likely to be included prior to publication. In recognition of this, we would appreciate any comments or critics you might have on our research or this document. We welcome any opportunity to improve or clarify any part of our discussion, or to expand upon points of particular interest.
An unstructured grid generation method based o s the Delaunay triangulation is presented that is ... more An unstructured grid generation method based o s the Delaunay triangulation is presented that is capable of generating stretched layers along surface lines while retaining strong control over maximum angles. The method requires only minimum user input in form of a set of boundary nodes, the character of each boundary, the thickness of the stretched layer and the maximum aspect ratio desired. Upper and lower angular bounds and an upper bound in surface variation between neighboring cells are proven. 2 Generation of the background mesh The Delaunay triangulation of all boundary nodes is computed as an initial triangulation to begin the node gen
Solution adaptive mesh refinement using adjoint error analysis. Jens-Dominik Mueller, Michael B G... more Solution adaptive mesh refinement using adjoint error analysis. Jens-Dominik Mueller, Michael B Giles AIAA Computational Fluid Dynamics Conference, 15 th, Anaheim, CA, 2001. A solution adaptive mesh refinement method for unstructured meshes is presented. ...
A comparison of the treatment of hanging nodes for hybrid grid refinement. Jens-Dominik Mueller, ... more A comparison of the treatment of hanging nodes for hybrid grid refinement. Jens-Dominik Mueller, Thilo Schoenfeld, Michael Rudgyard AIAA, Computational Fluid Dynamics Conference, 13 th, Snowmass Village, CO, 1997. We ...
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