scholarly journals Using thermodynamic equilibrium models to predict the effect of antiviral agents on infectivity: Theoretical application to SARS-CoV-2 and other viruses.

2021 ◽  
pp. 100198
Author(s):  
Paul Gale
Keyword(s):  
Thermodynamic Equilibrium ◽  
Antiviral Agents ◽  
Equilibrium Models ◽  
Theoretical Application

scholarly journals A Holistic Review on Biomass Gasification Modified Equilibrium Models

Energies ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 160 ◽  
Author(s):  
Sérgio Ferreira ◽  
Eliseu Monteiro ◽  
Paulo Brito ◽  
Cândida Vilarinho
Keyword(s):  
Mathematical Models ◽  
Thermodynamic Equilibrium ◽  
Model Prediction ◽  
Biomass Gasification ◽  
Correction Factors ◽  
Equilibrium Models ◽  
Gasification Process ◽  
Empirical Correction ◽  
Holistic Review ◽  
Almost All

Biomass gasification is realized as a settled process to produce energy in a sustainable form, between all the biomass-based energy generation routes. Consequently, there are a renewed interest in biomass gasification promoting the research of different mathematical models to enlighten and comprehend gasification process complexities. This review is focused on the thermodynamic equilibrium models, which is the class of models that seems to be more developed. It is verified that the review articles available in the literature do not address non-stoichiometric methods, as well as an ambiguous categorization of stoichiometric and non-stoichiometric methods. Therefore, the main purpose of this article is to review the non-stoichiometric equilibrium models and categorize them, and review the different stoichiometric equilibrium model’s categorization available in the literature. The modeling procedures adopted for the different modeling categories are compared. Conclusion can be drawn that almost all equilibrium models are modified by the inclusion of empirical correction factors that improves the model prediction capabilities but with loss of generality.

scholarly journals A critical evaluation of proxy methods used to estimate the acidity of atmospheric particles

2014 ◽  
Vol 14 (20) ◽  
pp. 27579-27618 ◽  
Author(s):  
C. J. Hennigan ◽  
J. Izumi ◽  
A. P. Sullivan ◽  
R. J. Weber ◽  
A. Nenes
Keyword(s):  
Thermodynamic Equilibrium ◽  
Critical Evaluation ◽  
Atmospheric Particles ◽  
Molar Ratio ◽  
Ratio Method ◽  
Thermodynamic Models ◽  
Equilibrium Models ◽  
Ion Balance ◽  
Phase Partitioning ◽  
Aerosol Acidity

Abstract. Given significant challenges with available measurements of aerosol acidity, proxy methods are frequently used to estimate the acidity of atmospheric particles. In this study, four of the most common aerosol acidity proxies are evaluated and compared: (1) the ion balance method, (2) the molar ratio method, (3) thermodynamic equilibrium models, and (4) the phase partitioning of ammonia. All methods are evaluated against predictions of thermodynamic models and against direct observations of aerosol-gas equilibrium partitioning acquired in Mexico City during the MILAGRO study. The ion balance and molar ratio methods assume that any deficit in inorganic cations relative to anions is due to the presence of H+; and that a higher H+ loading and lower cation/anion ratio both correspond to increasingly acidic particles (i.e., lower pH). Based on the MILAGRO measurements, no correlation is observed between H+ levels inferred with the ion balance and aerosol pH predicted by the thermodynamic models and ammonia–ammonium (NH3–NH4+) partitioning. Similarly, no relationship is observed between the cation / anion molar ratio and predicted aerosol pH. Using only measured aerosol chemical composition as inputs without any constraint for the gas phase, the Extended Aerosol Inorganics Model (E-AIM) and ISORROPIA-II thermodynamic equilibrium models tend to predict aerosol pH levels that are inconsistent with the observed NH3–NH4+ partitioning. The modeled pH values from both models run with gas + aerosol inputs agreed well with the aerosol pH predicted by the phase partitioning of ammonia. It appears that (1) thermodynamic models constrained by gas + aerosol measurements, and (2) the phase partitioning of ammonia provide the best available predictions of aerosol pH. Furthermore, neither the ion balance nor the molar ratio can be used as surrogates for aerosol pH, and published studies to date with conclusions based on such acidity proxies may need to be reevaluated. Given the significance of acidity for chemical processes in the atmosphere, the implications of this study are important and far reaching.

scholarly journals AEROSOL pH IN HO CHI MINH CITY, VIET NAM

2018 ◽  
Vol 55 (4C) ◽  
pp. 72
Author(s):  
Duong Huu Huy
Keyword(s):  
Particulate Matter ◽  
Air Quality ◽  
Thermodynamic Equilibrium ◽  
Fine Particulate Matter ◽  
Terrestrial Ecosystems ◽  
Ho Chi Minh City ◽  
Viet Nam ◽  
Equilibrium Models ◽  
Phase Partitioning ◽  
Fine Particulate

Aerosol pH is an important parameter that affects air quality, and the health of aquatic and terrestrial ecosystems. However, the lack of such data was reported in Ho Chi Minh City (HCMC), Vietnam. In this study, we estimated the aerosol pH in fine particulate matter (PM2.5) collected in HCMC, Vietnam using the thermodynamic equilibrium models (E-AIM Extended Aerosol Inorganics Model and ISORROPIA-II), and the phase partitioning of ammonia. Aerosol pHs estimated by different methods were 1.7 – 2.9. Good correlations between the phase-partitioning approach and models in predicting the aerosol pH were observed with R2 from 0.77 to 0.89, suggesting that the assumption of equilibrium is valid at the HCMC site.

scholarly journals A critical evaluation of proxy methods used to estimate the acidity of atmospheric particles

2015 ◽  
Vol 15 (5) ◽  
pp. 2775-2790 ◽  
Author(s):  
C. J. Hennigan ◽  
J. Izumi ◽  
A. P. Sullivan ◽  
R. J. Weber ◽  
A. Nenes
Keyword(s):  
Thermodynamic Equilibrium ◽  
Critical Evaluation ◽  
Atmospheric Particles ◽  
Molar Ratio ◽  
Ratio Method ◽  
Thermodynamic Models ◽  
Equilibrium Models ◽  
Ion Balance ◽  
Phase Partitioning ◽  
Aerosol Acidity

Abstract. Given significant challenges with available measurements of aerosol acidity, proxy methods are frequently used to estimate the acidity of atmospheric particles. In this study, four of the most common aerosol acidity proxies are evaluated and compared: (1) the ion balance method, (2) the molar ratio method, (3) thermodynamic equilibrium models, and (4) the phase partitioning of ammonia. All methods are evaluated against predictions of thermodynamic models and against direct observations of aerosol–gas equilibrium partitioning acquired in Mexico City during the Megacity Initiative: Local and Global Research Objectives (MILAGRO) study. The ion balance and molar ratio methods assume that any deficit in inorganic cations relative to anions is due to the presence of H+ and that a higher H+ loading and lower cation / anion ratio both correspond to increasingly acidic particles (i.e., lower pH). Based on the MILAGRO measurements, no correlation is observed between H+ levels inferred with the ion balance and aerosol pH predicted by the thermodynamic models and NH3–NH4+ partitioning. Similarly, no relationship is observed between the cation / anion molar ratio and predicted aerosol pH. Using only measured aerosol chemical composition as inputs without any constraint for the gas phase, the E-AIM (Extended Aerosol Inorganics Model) and ISORROPIA-II thermodynamic equilibrium models tend to predict aerosol pH levels that are inconsistent with the observed NH3–NH4+ partitioning. The modeled pH values from both E-AIM and ISORROPIA-II run with gas + aerosol inputs agreed well with the aerosol pH predicted by the phase partitioning of ammonia. It appears that (1) thermodynamic models constrained by gas + aerosol measurements and (2) the phase partitioning of ammonia provide the best available predictions of aerosol pH. Furthermore, neither the ion balance nor the molar ratio can be used as surrogates for aerosol pH, and previously published studies with conclusions based on such acidity proxies may need to be reevaluated. Given the significance of acidity for chemical processes in the atmosphere, the implications of this study are important and far reaching.

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