Interaction between electrostatics and fluid dynamics in electrostatic precipitators

Significant effort has been devoted by past researchers in electrostatic precipitators to electrostatics and particle chemistry. Relatively little, however, has been published on the effect of turbulent flow and its interaction with electrostatics and particle dynamics. This paper describes an experiment and a fundamental model which is focused on the coupled effects of the fluid dynamics and electrostatics.A laboratory precipitator flow facility with laser beam illumination was used to visualize smoke flow. Detailed photographs of flow patterns with and without electric field were recorded in a horizontal plane through the precipitator.A theoretical model was used to numerically simulate the observed flow patterns in the experiment. In the model the flow was described by time-averaged mass and momentum equations with a two-equation turbulence model. The electric field was described by Maxwell electrostatic equation and the continuity of the current equation. The system of the coupled partial differential equations was solved by a finite difference scheme.The interaction between fluid dynamics and electrostatics is shown to have a significant role in altering the flow in the precipitator. The practical implication is that the interaction will aid in particle migration in some regions, but it will increase reentrainment and reduce particle migration in others. Comparison between the results from the experiment and numerical computations shows good qualitative agreement between the two. Since both the electrostatic and the fluid dynamic flow fields depend on the electrode geometry, further investigation may lead to improved design of precipitators.     

Strong link between coronavirus count and bad air: a case study of India

Environment, Development and Sustainability - The present study aims to highlight the contrast relationship between COVID-19 (Coronavirus Disease-2019) infections and air pollutants for the Indian...     

Ruffed grouse brood habitat on reclaimed surface mines in West Virginia

Human-imprinted ruffed grouse (Bonasa umbellus) chicks were used to evaluate grouse brood food and cover conditions on reclaimed surface mines in northern West Virginia. Reclaimed surface-mined areas did not provide the quality of habitat for ruffed grouse chicks that unmined land provided. On the surface-mined areas, grasslegume reclamation provided the poorest cover and next to the lowest feeding rates. Of the surface-mined areas a 25-year-old reclaimed mine planted to autumn olive had canopy provided a more favorable micro-climate for insects and herbaceous vegetation was established around the edge. Planting rows of shrubs in addition to the current practice of planting grasses and legumes on surface-mined areas is suggested to create ruffed grouse brood habitat.     

Application of decision tools to ethical analysis in biodiversity conservation

Achieving ethically responsible decisions is crucial for the success of biodiversity conservation projects. We adapted the ethical matrix, decision tree, and Bateson's cube to assist in the ethical analysis of complex conservation scenarios by structuring these tools so that they can implement the different value dimensions (environmental, social, and animal welfare) involved in conservation ethics. We then applied them to a case study relative to the decision-making process regarding whether or not to continue collecting biomaterial on the oldest of the two remaining northern white rhinoceroses (Ceratotherium simum cottoni), a functionally extinct subspecies of the white rhinoceros. We used the ethical matrix to gather ethical pros and cons and as a starting point for a participatory approach to ethical decision-making. We used decision trees to compare the different options at stake on the basis of a set of ethical desiderata. We used Bateson's cube to establish a threshold of ethical acceptability and model the results of a simple survey. The application of these tools proved to be pivotal in structuring the decision-making process and in helping reach a shared, reasoned, and transparent decision on the best option from an ethical point of view among those available.     

Environmental risk assessment in five rivers of Parana River basin,Southern Brazil,through biomarkers in Astyanax spp.

Environmental Science and Pollution Research - In the current study, water quality of five river sites in Parana River basin (Brazil), utilized for public water supply, was assessed through a set...     

Methyl tertiary hexyl ether and methyl tertiary octyl ether as gasoline oxygenates: assessing risks from atmospheric dispersion and deposition

Methyl tertiary hexyl ether (MtHxE) and methyl tertiary octyl ether (MtOcE) are currently being developed as replacement oxygenates for methyl tertiary butyl ether (MtBE) in gasoline. As was the case with MtBE, the introduction of these ethers into fuel supplies guarantees their introduction into the environment as well. In this study, a screening-level risk assessment was performed by comparing predicted environmental concentrations (PEC) of these ethers to concentrations that might cause adverse effects to humans or ecosystems. A simple box model that has successfully estimated urban air concentrations of MtBE was adapted to predict atmospheric concentrations of MtHxE and MtOcE. Expected atmospheric concentrations of these ethers were also estimated using the European Union System for the Evaluation of Substances (EUSES) multimedia fate model, which simultaneously calculates PECs in the various environmental compartments of air, water, soil, and sediment. Because little or no data are available on the physicochemical, environmental, and toxicological properties of MtHxE and MtOcE, estimation methods were used in conjunction with EUSES to predict both the PECs and the concentrations at which these ethers might pose a threat. The results suggest that these ethers would contaminate the air of a moderately sized U.S. city (Boston, MA) at levels similar to those found previously for MtBE. The risk assessment module in EUSES predicted risk characterization ratios of 10(-3) and 10(-2) for MtHxE and MtOcE, respectively, in Boston, and 10(-2) and 10(-1) in very large urban centers, suggesting that these ethers pose only a minimal threat to ecosystems at the anticipated environmental concentrations. The assessment also indicates that these compounds are possible human carcinogens and that they may be present in urban air at concentrations that pose an unacceptable cancer risk. Therefore, testing of the toxicological properties of these compounds is recommended before they replace MtBE in gasoline.     

Biodynamic modelling and the prediction of accumulated trace metal concentrations in the polychaete Arenicola marina

The use of biodynamic models to understand metal uptake directly from sediments by deposit-feeding organisms still represents a special challenge. In this study, accumulated concentrations of Cd, Zn and Ag predicted by biodynamic modelling in the lugworm Arenicola marina have been compared to measured concentrations in field populations in several UK estuaries. The biodynamic model predicted accumulated field Cd concentrations remarkably accurately, and predicted bioaccumulated Ag concentrations were in the range of those measured in lugworms collected from the field. For Zn the model showed less but still good comparability, accurately predicting Zn bioaccumulation in A. marina at high sediment concentrations but underestimating accumulated Zn in the worms from sites with low and intermediate levels of Zn sediment contamination. Therefore, it appears that the physiological parameters experimentally derived for A. marina are applicable to the conditions encountered in these environments and that the assumptions made in the model are plausible.     

Design for occupational safety and health of workers in construction in developing countries: a study of architects in Nigeria

Purpose. Design for safety (DfS) of workers is amongst the prominent ways of tackling poor occupational safety and health performance in construction. However, in developing countries there is extremely limited research on DfS. This study thus makes an important contribution to the subject of DfS in developing countries by specifically examining the awareness and practice of DfS amongst architects within the construction sector of Nigeria. Materials and methods. A survey of architects, yielding 161 valid responses, was conducted. Results. While there is high awareness of the concept of DfS, the actual practice is low. Additionally, although there is high interest in DfS training, the engagement in DfS training is low. Significantly, awareness of DfS, training and education related to DfS, and membership of a design professional body have very limited bearing on the practice of DfS by architects. Conclusions. The findings are thus symptomatic of the prevalence of influential DfS implementation barriers within the construction sector. Industry stakeholders should seek to raise the profile of DfS practice within the sector. Furthermore, similar empirical studies in the construction sector of other developing countries would be useful in shedding light on the status of DfS in these countries.