Optimized processing power and trainability of neural network in numerical modeling of Al Matrix nano composites

In this research, an experimental study of reinforcing alumina nano-particles into the aluminum alloy matrix was implemented to verify the accuracy of modeling results obtained by feed forward neural networks. Artificial neural network combined with numerical technique were used to predict the various parameters of mechanical properties such as hardness, tensile and compressive yield stress, UTS and elongation percentage. Much experimentation were taken to discover a suitable number of hidden neurons, avoid detraction from the trainability and enable feed forward neural networks to solve more complex problems. The predictions were found to be consistent with experimental measurements.     

Are photocatalytic processes effective for removal of airborne viruses from indoor air? A narrative review

A wide variety of methods have been applied in indoor air to reduce the microbial load and reduce the transmission rate of acute respiratory diseases to personnel in healthcare sittings. In recent months, with the occurrence of COVID-19 pandemic, the role of portable ventilation systems in reducing the load of virus in indoor air has received much attention. The present study delineates a comprehensive up-to-date overview of the available photocatalysis technologies that have been applied for inactivating and removing airborne viruses. The detection methods for identifying viral particles in air and the main mechanisms involving in virus inactivation during photocatalysis are described and discussed. The photocatalytic processes could effectively decrease the load of viruses in indoor air. However, a constant viral model may not be generalizable to other airborne viruses. In photocatalytic processes, temperature and humidity play a distinct role in the inactivation of viruses through changing photocatalytic rate. The main mechanisms for inactivation of airborne viruses in the photocatalytic processes included chemical oxidation by the reactive oxygen species (ROS), the toxicity of metal ions released from metal-containing photocatalysts, and morphological damage of viruses.

     

Accuracy,uncertainty, and interpretability assessments of ANFIS models to predict dust concentration in semi-arid regions

Environmental Science and Pollution Research - Accurate prediction of the dust concentration (DC) is necessary to reduce its undesirable environmental effects in different geographical areas....     

Global trends and characteristics of vermicompost research over the past 24 years

This study aims to investigate a practical bibliometric analysis and discuss its trends to evaluate the global scientific production of vermicompost research from 1993 to 2017 and explain its several advantages to our environment and waste management. The data were from the database of the Science Citation Index (SCI) published by the ISI Web of Science and illustrated by Excel and VOS viewer. According to the 2174 publications, this article was conducted based on four significant aspects, including publications growth trends, countries/territories, categories and journals, and keywords co-occurrence network analysis. This study revealed remarkable positive growth trends of the research and the number of articles related to vermicompost over the last 24 years with more countries participating in this field. Although the USA has the most collaboration with other countries, developing countries such as India, which was the most productive one, made significant progress in sharing articles within the study period. Based on analyses of dominant categories, the most common subject category was Environmental Science, and the most productive journal was Bioresource Technology. Finally, we analyzed author keywords to the extracted research article emphasis. The results showed that mainstream research claim vermicomposting with the help of Eisenia fetida earthworms which converts several wastes such as sewage sludge to a soil improvement fertilizer. It is an essential approach to eliminate heavy metals from the wastes and provide essential nutrients to improve the growth and yield of plants.

     

Rapid photodegradation and detection of zolpidem over β-SnWO4 and α-SnWO4 nanoparticles: optimization and mechanism

Environmental Science and Pollution Research - We reported the tin (II) tungstate nanoparticles as the photocatalyst and sensor modifier that were synthesized via chemical precipitation reaction...     

Evaluation of the available strategies to control the emission of microplastics into the aquatic environment

Environmental Science and Pollution Research - No effective strategy has been found so far to control the emission of microplastics. The purpose of this article is to review the available control...     

Comparative cancer risk assessment of THMs in drinking water from well water sources and surface water sources

This research evaluates the lifetime cancer risks from trihalomethanes in Tehran's drinking water. The Trihalomethanes were measured in seven different water districts. Sixty-three samples were taken from tap water across the city for 7 months. The samples were analyzed for trihalomethanes using US EPA method 524.2. The average concentration of total trihalomethanes in different districts were between 0.81 and 9.0 μg/L, and the highest concentrations were detected in district 2 at 19.5 μg/L. Total lifetime cancer risks assessment from exposure to trihalomethanes in drinking water (ingestion, inhalation, and skin routes) were performed for people living in different districts in Tehran. The lifetime cancer risk was 7.19 × 10(-5) in district 2 (a more affluent neighborhood) where mostly surface water sources is used to supply drinking water and 9.38 × 10(-6) in district 7 (a less affluent neighborhood) which is mainly supplied with well water sources. Based on the population data, the total expected lifetime cancer cases from exposure to trihalomethanes are 104, 108, 81, 81, 41, 27, and three for districts 1 through 7, respectively. The average lifetime cancer risk was 4.33 × 10(-5) which means a total of 606 lifetime cancer cases for the entire province of Tehran. The highest risk from THMs seems to be from the inhalation route followed by ingestion and dermal contacts.     

Examination of the operator and compensator tank role in urban wastewater treatment using activated sludge method

No doubt, operator is one of the main fundaments in wastewater treatment plants. By identifying the inadequacies, the operator could be considered as an important key in treatment plant. Several methods are used for wastewater treatment that requires spending a lot of cost. However, all investments of treatment facilities are useable when the expected efficiency of the treatment plant was obtained. Using experienced operator, this goal is more easily accessible. In this research, the wastewater of an urban community contaminated with moderated, diluted and highly concentrated pollution has been treated using surface and deep aeration treatment method. Sampling of these pilots was performed during winter 2008 to summer 2009. The results indicate that all analyzed parameters were eliminated using activated sludge and surface aeration methods. However, in activated sludge and deep aeration methods in combination with suitable function of operator, more pollutants could be eliminated. Hence, existence of operator in wastewater treatment plants is the basic principle to achieve considered efficiency. Wastewater treatment system is not intelligent itself and that is the operator who can organize even an inefficient system by its continuous presence. The converse of this fact is also real. Despite the various units and appropriate design of wastewater treatment plant, without an operator, the studied process cannot be expected highly efficient. In places frequently affected by the shock of organic and hydraulic loads, the compensator tank is important to offset the wastewater treatment process. Finally, in regard to microbial parameters, existence of disinfection unit is very useful.     

Stand-alone PV-hydrogen energy system in Taleghan-Iran using HOMER software: optimization and techno-economic analysis

One of the most attractive features of hydrogen as an energy carrier is that it can be produced from water. Hydrogen has the highest energy content per unit mass as compared to chemical fuel and can be substituted. Its burning process is non-polluting, and it can be used in the fuel cells to produce both electricity and useful heat. Photovoltaic arrays can be used in supplying the water electrolysis systems by their energy requirements. During the daylight hours, the sunlight on the photovoltaic array converts into electrical energy which can be used for electrolyzer. The hydrogen produced by the electrolyzer is compressed and stored in hydrogen vessel and provides energy for the fuel cell to meet the load when the solar energy is insufficient. This study investigates a stand-alone power system that consists of PV array as power supply and electrolyzer. They have been integrated and worked at the Taleghan renewable energies’ site in Iran. The National Renewable Energy Laboratory’s Hybrid Optimization Model for Electric Renewables simulation software has been used to carry out the optimal design and techno-economic viability of the energy system. The simulation results demonstrate that energy system is composed of 10-kW PV array, 3.5-kW electrolyzer, 0.4-kW proton exchange membrane fuel cell, 2.5-kW inverter, and 60 batteries (100 Ah and 12 V). The total initial capital cost, net present cost, and cost of electricity produced from this energy system are 193,563 US$, 237,509 US$, and 3.35 US$/kWh, respectively.     

Electrochemical treatment of livestock waste streams. A review

Environmental Chemistry Letters - Wastewater from the livestock industries contains high concentration of nutrients, organic pollutants, suspended solids, and pathogenic microorganisms. Discharge...