Pub Date : 2023-09-01DOI: 10.1080/02786826.2023.2253302
Nicolas Castro, Qiang Wang, Jingjie Zhang, Weiling Li, Y. Pithawalla, Michael Oldham, Ali Rostami
Abstract A unique adult human mouth/throat physical model has been developed to study e-cigarette aerosol dynamics during inhalation. The 3D printed physical model was created from the CT scan of a 28 yr. old healthy male. Internal walls of the physical model were lined with a thin layer of cotton gauze that can be saturated with water to replicate the high relative humidity conditions in a human Oral/Pharyngeal cavity. Aerosol hygroscopic growth and deposition inside the physical model from a cartomizer style e-cigarette using a prototype e-liquid formulation was determined by measuring cumulative aerosol mass from five puffs (gravimetric) and for individual constituents (propylene glycol, glycerol, and nicotine) from a single puff (GC/MS analysis). Measurements were taken at constant temperature of 37 °C under both wet and dry inner wall conditions for a for a 3-sec. 55 mL puff. The condition of holding aerosol inside the physical model without airflow for a duration of 3-sec. was also included. For the same puffing conditions of 3-sec puff of 55 mL and a 3-sec. puff hold time, dry wall conditions resulted in a mean aerosol mass loss of 20.9 ± 3.8%, while the total aerosol mass was increased by 150.9 ± 19% under wet wall condition when compared to total aerosol mass entering the physical model entrance. The dramatic increase is due to water vapor uptake by the aerosol particles when flowing through the wetted physical model. Aerosol evolution of individual chemical constituent analysis appeared to vary as a function of volatility.
{"title":"Application of a Physical Model of the Human Mouth and Throat to Study the Complex Dynamics of Inhaled Aerosols","authors":"Nicolas Castro, Qiang Wang, Jingjie Zhang, Weiling Li, Y. Pithawalla, Michael Oldham, Ali Rostami","doi":"10.1080/02786826.2023.2253302","DOIUrl":"https://doi.org/10.1080/02786826.2023.2253302","url":null,"abstract":"Abstract A unique adult human mouth/throat physical model has been developed to study e-cigarette aerosol dynamics during inhalation. The 3D printed physical model was created from the CT scan of a 28 yr. old healthy male. Internal walls of the physical model were lined with a thin layer of cotton gauze that can be saturated with water to replicate the high relative humidity conditions in a human Oral/Pharyngeal cavity. Aerosol hygroscopic growth and deposition inside the physical model from a cartomizer style e-cigarette using a prototype e-liquid formulation was determined by measuring cumulative aerosol mass from five puffs (gravimetric) and for individual constituents (propylene glycol, glycerol, and nicotine) from a single puff (GC/MS analysis). Measurements were taken at constant temperature of 37 °C under both wet and dry inner wall conditions for a for a 3-sec. 55 mL puff. The condition of holding aerosol inside the physical model without airflow for a duration of 3-sec. was also included. For the same puffing conditions of 3-sec puff of 55 mL and a 3-sec. puff hold time, dry wall conditions resulted in a mean aerosol mass loss of 20.9 ± 3.8%, while the total aerosol mass was increased by 150.9 ± 19% under wet wall condition when compared to total aerosol mass entering the physical model entrance. The dramatic increase is due to water vapor uptake by the aerosol particles when flowing through the wetted physical model. Aerosol evolution of individual chemical constituent analysis appeared to vary as a function of volatility.","PeriodicalId":7474,"journal":{"name":"Aerosol Science and Technology","volume":" ","pages":""},"PeriodicalIF":5.2,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48850190","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-22DOI: 10.1080/02786826.2023.2244548
R. V. Vander Wal, Madhu Singh, W. Bachalo, G. Payne, J. Manin, R. Howard
Abstract Carbonaceous particulate produced by a diesel engine and turbojet engine combustor are analyzed by transmission electron microscopy (TEM) for differences in nanostructure before and after pulsed laser annealing. Soot is examined between low/high diesel engine torque and low/high turbojet engine thrust. Small differences in nascent nanostructure are magnified by the action of high-temperature annealing induced by pulsed laser heating. Lamellae length distributions show occurrence of graphitization while tortuosity analyses reveal lamellae straightening. Differences in internal particle structure (hollow shells versus internal graphitic ribbons) are interpreted as due to higher internal sp3 and O-atom content under the higher power conditions with hypothesized greater turbulence and resulting partial premixing. TEM in concert with fringe analyses reveal that a similar degree of annealing occurs in the primary particles in soot from both diesel engine and turbojet engine combustors—despite the aggregate and primary size differences between these sources. Implications of these results for source identification of the combustion particulate and for laser-induced incandescence (LII) measurements of concentration are discussed with inter-instrument comparison of soot mass from both diesel and turbojet soot sources. Graphical Abstract
{"title":"Pulsed laser heating of diesel engine and turbojet combustor soot: Changes in nanostructure and implications","authors":"R. V. Vander Wal, Madhu Singh, W. Bachalo, G. Payne, J. Manin, R. Howard","doi":"10.1080/02786826.2023.2244548","DOIUrl":"https://doi.org/10.1080/02786826.2023.2244548","url":null,"abstract":"Abstract Carbonaceous particulate produced by a diesel engine and turbojet engine combustor are analyzed by transmission electron microscopy (TEM) for differences in nanostructure before and after pulsed laser annealing. Soot is examined between low/high diesel engine torque and low/high turbojet engine thrust. Small differences in nascent nanostructure are magnified by the action of high-temperature annealing induced by pulsed laser heating. Lamellae length distributions show occurrence of graphitization while tortuosity analyses reveal lamellae straightening. Differences in internal particle structure (hollow shells versus internal graphitic ribbons) are interpreted as due to higher internal sp3 and O-atom content under the higher power conditions with hypothesized greater turbulence and resulting partial premixing. TEM in concert with fringe analyses reveal that a similar degree of annealing occurs in the primary particles in soot from both diesel engine and turbojet engine combustors—despite the aggregate and primary size differences between these sources. Implications of these results for source identification of the combustion particulate and for laser-induced incandescence (LII) measurements of concentration are discussed with inter-instrument comparison of soot mass from both diesel and turbojet soot sources. Graphical Abstract","PeriodicalId":7474,"journal":{"name":"Aerosol Science and Technology","volume":"57 1","pages":"1044 - 1056"},"PeriodicalIF":5.2,"publicationDate":"2023-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42764442","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-18DOI: 10.1080/02786826.2023.2242901
J. Rose, A. Kuczaj, A. Mukhin, J. Hoeng, K. Sai
Abstract We recently developed an in vitro system for quantification of deposited mass of labeled aerosol constituents in the human airway under realistic inhalation conditions including temperature and humidity control. The in vitro system consists of the upper respiratory airway cast with separate flow controls within distinct branches of the cast. The complete workflow including generation of the labeled aerosol particles, flow setup, and scanning deposited labeled constituent using positron emission tomography is presented. The system was used for evaluating deposition of 11C-radiolabeled nicotine from pH-modified liquid formulations generated by a typical tank electronic nicotine delivery system. The airway deposition patterns were modulated by adjusted liquid pH-value, suggesting modified gas-liquid aerosol partitioning. This can be visually assessed in a qualitative manner, but more importantly measured in a quantitative manner by evaluating the total administered dose. The effects of temperature and humidity were separately assessed, showing significant influence of realistic inhalation conditions (temperature of 37 °C and nearly 100% relative humidity) on total nicotine deposition in the airway cast. Developed capabilities allow their future applications in generating validation data for modeling purposes as well as for conducting further studies concerning understanding of challenges in aerosol delivery and dosimetry assessments.
{"title":"Deposition of 11C-radiolabeled nicotine-containing aerosol in an airway cast model using positron emission tomography (PET)","authors":"J. Rose, A. Kuczaj, A. Mukhin, J. Hoeng, K. Sai","doi":"10.1080/02786826.2023.2242901","DOIUrl":"https://doi.org/10.1080/02786826.2023.2242901","url":null,"abstract":"Abstract We recently developed an in vitro system for quantification of deposited mass of labeled aerosol constituents in the human airway under realistic inhalation conditions including temperature and humidity control. The in vitro system consists of the upper respiratory airway cast with separate flow controls within distinct branches of the cast. The complete workflow including generation of the labeled aerosol particles, flow setup, and scanning deposited labeled constituent using positron emission tomography is presented. The system was used for evaluating deposition of 11C-radiolabeled nicotine from pH-modified liquid formulations generated by a typical tank electronic nicotine delivery system. The airway deposition patterns were modulated by adjusted liquid pH-value, suggesting modified gas-liquid aerosol partitioning. This can be visually assessed in a qualitative manner, but more importantly measured in a quantitative manner by evaluating the total administered dose. The effects of temperature and humidity were separately assessed, showing significant influence of realistic inhalation conditions (temperature of 37 °C and nearly 100% relative humidity) on total nicotine deposition in the airway cast. Developed capabilities allow their future applications in generating validation data for modeling purposes as well as for conducting further studies concerning understanding of challenges in aerosol delivery and dosimetry assessments.","PeriodicalId":7474,"journal":{"name":"Aerosol Science and Technology","volume":"57 1","pages":"1057 - 1068"},"PeriodicalIF":5.2,"publicationDate":"2023-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45325433","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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