ABSTRACT
Pathogen droplets released from respiratory events are the primary means of dispersion and transmission of the recent pandemic of COVID-19. Computational fluid dynamics (CFD) has been widely employed as a fast, reliable, and inexpensive technique to support decision-making and to envisage mitigatory protocols. Nonetheless, the airborne pathogen droplet CFD modeling encounters limitations due to the oversimplification of involved physics and the intensive computational demand. Moreover, uncertainties in the collected clinical data required to simulate airborne and aerosol transport such as droplets' initial velocities, tempo-spatial profiles, release angle, and size distributions are broadly reported in the literature. There is a noticeable inconsistency around these collected data amongst many reported studies. This study aims to review the capabilities and limitations associated with CFD modeling. Setting the CFD models needs experimental data of respiratory flows such as velocity, particle size, and number distribution. Therefore, this paper briefly reviews the experimental techniques used to measure the characteristics of airborne pathogen droplet transmissions together with their limitations and reported uncertainties. The relevant clinical data related to pathogen transmission needed for postprocessing of CFD data and translating them to safety measures are also reviewed. Eventually, the uncertainty and inconsistency of the existing clinical data available for airborne pathogen CFD analysis are scurtinized to pave a pathway toward future studies ensuing these identified gaps and limitations.
ABSTRACT
In the current global situation, the release of large amounts of potential effluents into the environment is considered as one of the most important and challenging issues. Innovations in the treatment methods to deal with this problem are among the research priorities within the scientific communities. Even though innumerable methods including physicochemical and biological have been used, yet no proper sustainability of the methods have been introduced. Membrane bioreactors (MBRs) have gained world-wide attention in recent years, but still there is no report in the literature to map the global research on this subject. The present manuscript describes a scientometric study on the global trend on the application of MBRs during the period 1991-2018 by employing variables such as: (1) distribution of documents over the adopted duration, (2) type of documents in this area, (3) rate of contribution among the different countries, (4) rate of cooperation among the authors, (5) frequency of the keywords co-occurring, (6) cited authors, (7) cited journals, (8) the frequency of categories appeared and (9) the cited documents. A total of 2452 bibliographic records from the Web of Science database were retrieved and analysed to generate results, thereby to create geospatial maps for a better understanding. The findings reveal an increase in the number of papers published in the world, especially China and USA being the top. The existing studies in MBRs research focus mainly on subject categories of the performance and fouling as the main criteria of the sustainable application of MBRs. This study therefore, provides an extensive understanding about the trends and research patterns of MBRs efforts worldwide.
