CFD simulation of effects of dimension changes of buildings on pollution dispersion in the built environment

AbstractAs pollutions impose adverse effects on human health and environment, assessment of their dispersion within the urban regions can much help to control them. In urban regions, dynamics of pollutants will be affected by buildings and barriers, and to investigate the dispersion of the pollutants, these barriers must be considered. In this article, CFD simulation is done by applying the 3D approach, the k−ε Realizable turbulence model and two Schmidt numbers (0.3 and 0.7). It has seen that height, length and width of the building in front of the wind, and, the distance between the two buildings back to the main building (the building on which the stack is present), have much influence on the concentration of pollutions. Although there are some differences between the results with different Schmidt numbers, the trend of changes of the concentration in different locations is identical for the two Schmidt numbers

Comparison of Two Intravenous Fluid Maintenance Therapy with Different Sodium Concentrations in Hospitalized Children: A Randomized Trial Study

Introduction: Hyponatremia refers to the serum sodium levels less than 135 mEq/L, which can even lead to death. Accordingly, the present study compared the effects of intravenous fluid maintenance treatment with different concentration levels of sodium.Materials and Methods: In an investigative study to evaluate children admitted to the Pediatric Intensive Care Unit (PICU) of Bahrami Children's Hospital (2012-2013) which required intravenous fluid therapy and aged one to 14 years were evaluated. They were randomly divided into two groups: fluid treatment with 50 mEq/L (group I) and 100 mEq/L (group II) sodium concentrations. The fluids were calculated according to Holliday-Segar formula. Sodium of plasma [P (Na)] and Urine specific gravity (USG) were measured at the time of admittance (first P (Na) and USG) and 24 hrs after treatment (second P (Na) and USG).Results: 108 children were admitted into the study. Significant differences were noted in the second P (Na) levels and differing of first and second P (Na) (P<0.008 and P<0.011). In the first group, 14 cases and in second three cases were hyponatremia (P (Na) < 135 mmol/L), but they weren’t symptomatic during the study. The difference between first and second USG was greater in group I (P <0.023).Conclusions: There was relation between the sodium of the IV fluid and decreased P (Na) concentration in the children who were undergoing intravenous (IV) fluid therapy. There were no Symptomatic hyponatremia cases reported, due to the decrease of P (Na), nor in the 24 hours following the IV therapy treatment.    Keywords: Fluid Therapy; Specific Gravity; Sodium; Hyponatremi

Association between PM2.5 and risk of hospitalization for myocardial infarction: A systematic review and a meta-analysis

Background: It is generally assumed that there have been mixed results in the literature regarding the association between ambient particulate matter (PM) and myocardial infarction (MI). The aim of this meta-analysis was to explore the rate of short-term exposure PM with aerodynamic diameters �2.5 μm (PM2.5) and examine its potential effect(s) on the risk of MI. Methods: A systematic search was conducted on databases like PubMed, Scopus, Web of Science, and Embase with components: "air pollution" and "myocardial infarction". The summary relative risk (RR) and 95 confidence intervals (95CI) were also calculated to assess the association between the PM2.5 and MI. Results: Twenty-six published studies were ultimately identified as eligible candidates for the meta-analysis of MI until Jun 1, 2018. The results illustrated that a 10-μg/m 3 increase in PM2.5 was associated with the risk of MI (RR = 1.02; 95 CI 1.01-1.03; P � 0.0001). The heterogeneity of the studies was assessed through a random-effects model with p < 0.0001 and the I2 was 69.52, indicating a moderate degree of heterogeneity. We also conducted subgroup analyses including study quality, study design, and study period. Accordingly, it was found that subgroups time series study design and high study period could substantially decrease heterogeneity (I2 = 41.61, 41.78). Conclusions: This meta-analysis indicated that exposure-response between PM2.5 and MI. It is vital decision makers implement effective strategies to help improve air pollution, especially in developing countries or prevent exposure to PM2.5 to protect human health. © 2020 The Author(s)

Using Lattice Boltzmann Method to Investigate the Effects of Porous Media on Heat Transfer from Solid Block inside a Channel

A numerical investigation of forced convection in a channel with hot solid block inside a square porous block mounted on a bottom wall was carried out. The lattice Boltzmann method was applied for numerical simulations. The fluid flow in the porous media was simulated by Brinkman-Forchheimer model. The effects of parameters such as porosity and thermal conductivity ratio over flow pattern and thermal field were investigated. In this paper the effects of mentioned parameters were discussed in detail. The result show with increasing the thermal conductivity ratio and porosity the fluid temperature will reduce

Lattice Boltzmann Method in Modeling Biofilm Formation, Growth and Detachment

Biofilms are a complex and heterogeneous aggregation of multiple populations of microorganisms linked together by their excretion of extracellular polymer substances (EPS). Biofilms can cause many serious problems, such as chronic infections, food contamination and equipment corrosion, although they can be useful for constructive purposes, such as in wastewater treatment, heavy metal removal from hazardous waste sites, biofuel production, power generation through microbial fuel cells and microbially enhanced oil recovery; however, biofilm formation and growth are complex due to interactions among physicochemical and biological processes under operational and environmental conditions. Advanced numerical modeling techniques using the lattice Boltzmann method (LBM) are enabling the prediction of biofilm formation and growth and microbial community structures. This study is the first attempt to perform a general review on major contributions to LBM-based biofilm models, ranging from pioneering efforts to more recent progress. We present our understanding of the modeling of biofilm formation, growth and detachment using LBM-based models and present the fundamental aspects of various LBM-based biofilm models. We describe how the LBM couples with cellular automata (CA) and individual-based model (IbM) approaches and discuss their applications in assessing the spatiotemporal distribution of biofilms and their associated parameters and evaluating bioconversion efficiency. Finally, we discuss the main features and drawbacks of LBM-based biofilm models from ecological and biotechnological perspectives and identify current knowledge gaps and future research priorities

Employment Status of Midwifery Graduates of Babol University of Medical Sciences

Introduction. One of the important economical and social problems of our society is employment situation of higher education graduates which is necessary to consider for the development of future plans. This study aims to determine the employment situation of midwifery graduates in Babol University of Medical Sciences. Methods. In this cross-sectional survey, a questionnaire was sent to all midwifery graduates who had entered the university between 1992-1997 (n=120). A total number of 82 filled questionnaires were returned. The data analysis was done with SPSS-10 software using frequency distribution and Chi2 test. Results. Based on the results, 51.3% of subjects were employed which nearly half of them were spending their mandatory services. Statistical data revealed a significant relationship between the year of graduation and being employed. Twenty two point five percent of employed graduates worked in jobs other than midwifery. Eighty two point nine percent of them were employed at government section, 17.1% at private section and 75.9% of them did not have any office. There was a significant relationship between quota of acceptance to the university and the desire to work in deprived areas. Most midwives did not have any desire to work in the deprived areas, and in the case of having the opportunity to choose again, they would not choose midwifery as their future career. Conclusion. The unemployment rate between midwifery graduates of Babol medical university is high. So, it is recommended to provide them with appropriate job opportunities, and employ young graduates in counseling clinics for maternity car

The relationship between alexithymia and general symptoms of pregnant women

Introduction. Alexithymia is related to poor emotion regulation strategies as well as higher rates of somatic disorders. The aim of the present study was to assess the relationship between alexithymia and the general symptoms experienced by the pregnant women

Modelling phytoremediation: Concepts, methods, challenges and perspectives

Phytoremediation can be effective for the removal, immobilization, mineralization, and/or detoxification of various pollutants in soils and water, including inorganic and organic pollutants, and radioisotopes. Although the feasibility of phytoremediation has been proven in the last decades, its performance is uncertain due to the complex interactions among soil, water, plants, weather, microorganisms, and pollutants, leading to its underutilization globally. This paper aims to review the representations and methods for quantifying key phytoremediation processes via modelling. We examine the structures, methods and ability of phytoremediation models that characterize the biogeochemical, hydrological, and phenological processes accountable for phytoremediation dynamics, along with discussions about their advantages and limitations. Then, we identify the knowledge gaps and challenges in incorporating biogeochemical, hydrological, and phenological processes into phytoremediation models in contaminated sites and representing spatial heterogeneity and temporal variability in large-scale applications. The existing phytoremediation models are difficult to predict the phytoremediation period under real environmental conditions but it is a key assessment of phytoremediation performance and cost. Finally, we explore the opportunities to integrate the current knowledge from other disciplines, such as soil, agriculture, ecology, and plant research in a competition-based model. We highlight the key research priorities for effective integration of knowledge based on physical, chemical, and biological processes in modelling phytoremediation, including biogeochemical processes, soil amendments and agro-practices. Further studies need to consider the immobilization, mineralization and detoxification processes of pollutants in contaminated sites

EFFECT OF DISCRETE HEATER AT THE VERTICAL WALL OF THE CAVITY OVER THE HEAT TRANSFER AND ENTROPY GENERATION USING LBM

In this paper Lattice Boltzmann Method (LBM) was employed for investigation the effect of the heater location on flow pattern, heat transfer and entropy generation in a cavity. A 2D thermal lattice Boltzmann model with 9 velocities, D2Q9, is used to solve the thermal flow problem. The simulations were performed for Rayleigh numbers from 103 to 106 at Pr = 0.71. The study was carried out for heater length of 0.4 side wall length which is located at the right side wall. Results are presented in the form of streamlines, temperature contours, Nusselt number and entropy generation curves. Results show that the location of heater has a great effect on the flow pattern and temperature fields in the enclosure and subsequently on entropy generation. The dimensionless entropy generation decreases at high Rayleigh number for all heater positions. The ratio of averaged Nusselt number and dimensionless entropy generation for heater located on vertical and horizontal walls was calculated. Results show that higher heat transfer was observed from the cold walls when the heater located on vertical wall. On the other hand, heat transfer increases from the heater surface when it located on the horizontal wall