Η αριθμητική μοντελοποίηση της μεταφοράς σωματιδίων που βρίσκονται διασκορπισμένα σε ρέοντα βιορε... more Η αριθμητική μοντελοποίηση της μεταφοράς σωματιδίων που βρίσκονται διασκορπισμένα σε ρέοντα βιορευστά είναι ο βασικός σκοπός της παρούσας διατριβής. Συγκεκριμένα, διερευνώνται οι μηχανισμοί που διέπουν τις αλληλεπιδράσεις σωματιδίων – ρευστών χρησιμοποιώντας τεχνικές της δυναμικής ρευστών. Η συνεχής φάση (ρευστό) επιλύεται με χρήση υπάρχοντος κώδικα, ο οποίος βασίζεται σε μεθόδους της υπολογιστικής ρευστοδυναμικής (computational fluid dynamics – CFD). Ιδιαίτερη σημασία κατά την ανάπτυξη του μοντέλου δόθηκε στην επίλυση της μεταφοράς της σωματιδιακής φάσης με προσέγγιση Euler. Η χρήση της περιγραφής κατά Euler έχει ως αποτέλεσμα την άμεση αντιμετώπιση της διάχυσης των σωματιδίων και του υπολογισμού τη συγκέντρωσης τους. Ωστόσο, τα αδρανειακά φαινόμενα δεν ενσωματώνονται εύκολα στην κατά Euler μορφή της Εξίσωσης Μεταφοράς των Σωματιδίων (particle transport equation – PTE). Για να συμπεριληφθούν, επομένως, τα αδρανειακά φαινόμενα στην μεθοδολογία Euler, θα πρέπει να χρησιμοποιηθεί μια ...
International journal of occupational and environmental health, Jul 1, 2016
Occupational exposure to manufactured nanomaterials (MNMs) and its potential health impacts are o... more Occupational exposure to manufactured nanomaterials (MNMs) and its potential health impacts are of scientific and practical interest, as previous epidemiological studies associate exposure to nanoparticles with health effects, including increased morbidity of the respiratory and the circulatory system. To estimate the occupational exposure and effective internal doses in a real production facility of TiO2 MNMs during hypothetical scenarios of accidental release. Commercial software for geometry and mesh generation, as well as fluid flow and particle dispersion calculation, were used to estimate occupational exposure to MNMs. The results were introduced to in-house software to calculate internal doses in the human respiratory tract by inhalation. Depending on the accidental scenario, different areas of the production facility were affected by the released MNMs, with a higher dose exposure among individuals closer to the particles source. Granted that the study of the accidental relea...
Environmental science and pollution research international, 2018
The paper presents an integrated methodology that combines experimental and modeling techniques a... more The paper presents an integrated methodology that combines experimental and modeling techniques and links exposure to airborne particulate matter (PM) with internal dose in the respiratory system and burden in adjacent tissues over a period of time. The methodology is used to estimate doses in the respiratory systems of elders that reside in 10 elderly care centers (ECCs) in the metropolitan area of Lisbon. Measurements of PM were performed in the ECCs and combined with a time-budget survey for the occupants. This information served as input to the first model that estimated particle doses in the different regions of the respiratory tract of the elderly, and then a second model was used to calculate particle build-up in the alveolar region, the interstitium and the hilar lymph nodes of the elders over a 5-year exposure period. It was found that in 5 years of continuous exposure to the average particle concentration measured over all ECCs, 258 mg of all particles are deposited on the...
2020 IEEE 20th International Conference on Bioinformatics and Bioengineering (BIBE), 2020
The present work focuses on the study of particle deposition in the human lung under different br... more The present work focuses on the study of particle deposition in the human lung under different breathing patterns. Transport and deposition of particles, with diameters from a few nanometers to several micrometers, is calculated using a well validated, 1-D, fully Eulerian, mechanistic numerical model that solves the particle general dynamic equation in the whole lung taking into account breathing dynamics. The examined breathing patterns include normal breathing and a variety of abnormal ones with tidal volumes and/or breathing frequencies outside the normal ranges. The numerical experiments indicate that breathing patterns do not alter significantly whole lung deposition fraction. They do, however, affect where the deposited particles are located within the lung, and the effect varies for different sized particles.
Exposure to airborne particulate matter (PM) is of utmost importance in the area of nanotechnolog... more Exposure to airborne particulate matter (PM) is of utmost importance in the area of nanotechnology safety as it has been associated with increased hazard to human health. Exposure characterization of particle concentration by size though a key determinant of the ability of PM to induce adverse health effects, is not enough for assessment of its potential health impact; estimation of particle intake, translocation and clearance are equally important parameters. In the present study, a biomathematical, mechanistic model is used to calculate internal doses from PM exposure in an office environment. The model consists of two parts; the first is a lung transport and deposition model that deals with aerosol and breathing dynamics, whereas the second is a compartmental model that calculates particles clearance/retention. For the monitoring of the airborne exposure levels, a Grimm 1.108 spectrometer was used, measuring particles’ number concentration in a diameter range between 0.30μm and 2...
There are numerous applications that aerosols are used as drugs, where the delivery of the partic... more There are numerous applications that aerosols are used as drugs, where the delivery of the particulate matter in specific sites of the respiratory tract is crucial for their effectiveness. Aerosol flows in bifurcations, which can be considered as building blocks of the lungs, are therefore of great importance for biomedical applications. In the present study, in-house computational models are used for constructing the computational grid [Makris et al.,2011,Comp Meth in Biomech and Biomed Eng(In press)], calculating the fluid flow field [Neofytou & Tsangaris,2006,Int J for Numerical Meth in Fluid (51),p.489–510] and studying the transport and deposition of inertial particles [Pilou et al.,2011,Aerosol Sc & Tech(45),p.1376-1387] in a single physiologically realistic bifurcation under steady state inspiratory flow. The effects of fluid flow characteristics (Reynolds number, asymmetry in the branches) and particle size are investigated. The model results are compared with experimental f...
A numerical model for the simulation of aerosol flows via an Eulerian-Eulerian, one-way coupled, ... more A numerical model for the simulation of aerosol flows via an Eulerian-Eulerian, one-way coupled, two-phase flow description is presented. An in-house computational fluid dynamics code, which utilizes the finite volume method and incorporates high order discretisation schemes, is used to obtain the velocity and pressure fields of the gaseous (continuous) phase. A modified convective diffusion equation, which includes inertial, gravitational and diffusive particle transport, is solved by the use of computational fluid dynamics techniques in steady state. The model is validated by comparing the calculated laminar fluid flow and particle deposition fractions with experimental studies of aerosol flows in a laminar-flow 90o bend of circular cross-section. Model predictions are also compared to numerical predictions of Eulerian-Lagrangian models. Particle concentration profiles at different cross-section are calculated and deposition sites on the wall boundary are indicated. For the range ...
ABSTRACT This paper presents a general overview of the work carried out by European project SCAFF... more ABSTRACT This paper presents a general overview of the work carried out by European project SCAFFOLD (GA 280535) during its 30 months of life, with special emphasis on risk management component. The research conducted by SCAFFOLD is focused on the European construction sector and considers 5 types of nanomaterials (TiO2, SiO2, carbon nanofibres, cellulose nanofibers and nanoclays), 6 construction applications (Depollutant mortars, selfcompacting concretes, coatings, self-cleaning coatings, fire resistant panels and insulation materials) and 26 exposure scenarios, including lab, pilot and industrial scales. The document focuses on the structure, content and operation modes of the Risk Management Toolkit developed by the project to facilitate the implementation of “nano-management” in construction companies. The tool deploys and integrated approach OHSAS 18001 - ISO 31000 and is currently being validated on 5 industrial case studies.
Η αριθμητική μοντελοποίηση της μεταφοράς σωματιδίων που βρίσκονται διασκορπισμένα σε ρέοντα βιορε... more Η αριθμητική μοντελοποίηση της μεταφοράς σωματιδίων που βρίσκονται διασκορπισμένα σε ρέοντα βιορευστά είναι ο βασικός σκοπός της παρούσας διατριβής. Συγκεκριμένα, διερευνώνται οι μηχανισμοί που διέπουν τις αλληλεπιδράσεις σωματιδίων – ρευστών χρησιμοποιώντας τεχνικές της δυναμικής ρευστών. Η συνεχής φάση (ρευστό) επιλύεται με χρήση υπάρχοντος κώδικα, ο οποίος βασίζεται σε μεθόδους της υπολογιστικής ρευστοδυναμικής (computational fluid dynamics – CFD). Ιδιαίτερη σημασία κατά την ανάπτυξη του μοντέλου δόθηκε στην επίλυση της μεταφοράς της σωματιδιακής φάσης με προσέγγιση Euler. Η χρήση της περιγραφής κατά Euler έχει ως αποτέλεσμα την άμεση αντιμετώπιση της διάχυσης των σωματιδίων και του υπολογισμού τη συγκέντρωσης τους. Ωστόσο, τα αδρανειακά φαινόμενα δεν ενσωματώνονται εύκολα στην κατά Euler μορφή της Εξίσωσης Μεταφοράς των Σωματιδίων (particle transport equation – PTE). Για να συμπεριληφθούν, επομένως, τα αδρανειακά φαινόμενα στην μεθοδολογία Euler, θα πρέπει να χρησιμοποιηθεί μια ...
International journal of occupational and environmental health, Jul 1, 2016
Occupational exposure to manufactured nanomaterials (MNMs) and its potential health impacts are o... more Occupational exposure to manufactured nanomaterials (MNMs) and its potential health impacts are of scientific and practical interest, as previous epidemiological studies associate exposure to nanoparticles with health effects, including increased morbidity of the respiratory and the circulatory system. To estimate the occupational exposure and effective internal doses in a real production facility of TiO2 MNMs during hypothetical scenarios of accidental release. Commercial software for geometry and mesh generation, as well as fluid flow and particle dispersion calculation, were used to estimate occupational exposure to MNMs. The results were introduced to in-house software to calculate internal doses in the human respiratory tract by inhalation. Depending on the accidental scenario, different areas of the production facility were affected by the released MNMs, with a higher dose exposure among individuals closer to the particles source. Granted that the study of the accidental relea...
Environmental science and pollution research international, 2018
The paper presents an integrated methodology that combines experimental and modeling techniques a... more The paper presents an integrated methodology that combines experimental and modeling techniques and links exposure to airborne particulate matter (PM) with internal dose in the respiratory system and burden in adjacent tissues over a period of time. The methodology is used to estimate doses in the respiratory systems of elders that reside in 10 elderly care centers (ECCs) in the metropolitan area of Lisbon. Measurements of PM were performed in the ECCs and combined with a time-budget survey for the occupants. This information served as input to the first model that estimated particle doses in the different regions of the respiratory tract of the elderly, and then a second model was used to calculate particle build-up in the alveolar region, the interstitium and the hilar lymph nodes of the elders over a 5-year exposure period. It was found that in 5 years of continuous exposure to the average particle concentration measured over all ECCs, 258 mg of all particles are deposited on the...
2020 IEEE 20th International Conference on Bioinformatics and Bioengineering (BIBE), 2020
The present work focuses on the study of particle deposition in the human lung under different br... more The present work focuses on the study of particle deposition in the human lung under different breathing patterns. Transport and deposition of particles, with diameters from a few nanometers to several micrometers, is calculated using a well validated, 1-D, fully Eulerian, mechanistic numerical model that solves the particle general dynamic equation in the whole lung taking into account breathing dynamics. The examined breathing patterns include normal breathing and a variety of abnormal ones with tidal volumes and/or breathing frequencies outside the normal ranges. The numerical experiments indicate that breathing patterns do not alter significantly whole lung deposition fraction. They do, however, affect where the deposited particles are located within the lung, and the effect varies for different sized particles.
Exposure to airborne particulate matter (PM) is of utmost importance in the area of nanotechnolog... more Exposure to airborne particulate matter (PM) is of utmost importance in the area of nanotechnology safety as it has been associated with increased hazard to human health. Exposure characterization of particle concentration by size though a key determinant of the ability of PM to induce adverse health effects, is not enough for assessment of its potential health impact; estimation of particle intake, translocation and clearance are equally important parameters. In the present study, a biomathematical, mechanistic model is used to calculate internal doses from PM exposure in an office environment. The model consists of two parts; the first is a lung transport and deposition model that deals with aerosol and breathing dynamics, whereas the second is a compartmental model that calculates particles clearance/retention. For the monitoring of the airborne exposure levels, a Grimm 1.108 spectrometer was used, measuring particles’ number concentration in a diameter range between 0.30μm and 2...
There are numerous applications that aerosols are used as drugs, where the delivery of the partic... more There are numerous applications that aerosols are used as drugs, where the delivery of the particulate matter in specific sites of the respiratory tract is crucial for their effectiveness. Aerosol flows in bifurcations, which can be considered as building blocks of the lungs, are therefore of great importance for biomedical applications. In the present study, in-house computational models are used for constructing the computational grid [Makris et al.,2011,Comp Meth in Biomech and Biomed Eng(In press)], calculating the fluid flow field [Neofytou & Tsangaris,2006,Int J for Numerical Meth in Fluid (51),p.489–510] and studying the transport and deposition of inertial particles [Pilou et al.,2011,Aerosol Sc & Tech(45),p.1376-1387] in a single physiologically realistic bifurcation under steady state inspiratory flow. The effects of fluid flow characteristics (Reynolds number, asymmetry in the branches) and particle size are investigated. The model results are compared with experimental f...
A numerical model for the simulation of aerosol flows via an Eulerian-Eulerian, one-way coupled, ... more A numerical model for the simulation of aerosol flows via an Eulerian-Eulerian, one-way coupled, two-phase flow description is presented. An in-house computational fluid dynamics code, which utilizes the finite volume method and incorporates high order discretisation schemes, is used to obtain the velocity and pressure fields of the gaseous (continuous) phase. A modified convective diffusion equation, which includes inertial, gravitational and diffusive particle transport, is solved by the use of computational fluid dynamics techniques in steady state. The model is validated by comparing the calculated laminar fluid flow and particle deposition fractions with experimental studies of aerosol flows in a laminar-flow 90o bend of circular cross-section. Model predictions are also compared to numerical predictions of Eulerian-Lagrangian models. Particle concentration profiles at different cross-section are calculated and deposition sites on the wall boundary are indicated. For the range ...
ABSTRACT This paper presents a general overview of the work carried out by European project SCAFF... more ABSTRACT This paper presents a general overview of the work carried out by European project SCAFFOLD (GA 280535) during its 30 months of life, with special emphasis on risk management component. The research conducted by SCAFFOLD is focused on the European construction sector and considers 5 types of nanomaterials (TiO2, SiO2, carbon nanofibres, cellulose nanofibers and nanoclays), 6 construction applications (Depollutant mortars, selfcompacting concretes, coatings, self-cleaning coatings, fire resistant panels and insulation materials) and 26 exposure scenarios, including lab, pilot and industrial scales. The document focuses on the structure, content and operation modes of the Risk Management Toolkit developed by the project to facilitate the implementation of “nano-management” in construction companies. The tool deploys and integrated approach OHSAS 18001 - ISO 31000 and is currently being validated on 5 industrial case studies.
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