Randomly selected order statistics in ranked set sampling: A less expensive comparable alternative to simple random sampling

Rank-based sampling designs are powerful alternatives to simple random sampling (SRS) and often provide large improvements in the precision of estimators. In many environmental, ecological, agricultural, industrial and/or medical applications the interest lies in sampling designs that are cheaper than SRS and provide comparable estimates. In this paper, we propose a new variation of ranked set sampling (RSS) for estimating the population mean based on the random selection technique to measure a smaller number of observations than RSS design. We study the properties of the population mean estimator using the proposed design and provide conditions under which the mean estimator performs better than SRS and some existing rank-based sampling designs. Theoretical results are augmented with some numerical studies and a real-life example, where we also study the performance of our proposed design under perfect and imperfect ranking situations.     

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...     

Composition of heavy metals and airborne fibers in the indoor environment of a building during renovation

The renovation of a building will certainly affect the quality of air in the vicinity of where associated activities were undertaken, this includes the quality of air inside the building. Indoor air pollutants such as particulate matter, heavy metals, and fine fibers are likely to be emitted during renovation work. This study was conducted to determine the concentration of heavy metals, asbestos and suspended particulates in the Biology Building, at the Universiti Kebangsaan, Malaysia (UKM). Renovation activities were carried out widely in the laboratories which were located in this building. A low-volume sampler was used to collect suspended particulate matter of a diameter size less than 10 μm (PM??) and an air sampling pump, fitted with a cellulose ester membrane filter, were used for asbestos sampling. Dust was collected using a small brush and scope. The concentration of heavy metals was determined through the use of inductively coupled plasma-mass spectroscopy and the fibers were counted through a phase contrast microscope. The concentrations of PM?? recorded in the building during renovation action (ranging from 166 to 542 μg m?3) were higher than the value set by the Department of Safety and Health for respirable dust (150 μg m?3). Additionally, they were higher than the value of PM?? recorded in indoor environments from other studies. The composition of heavy metals in PM?? and indoor dust were found to be dominated by Zn and results also showed that the concentration of heavy metals in indoor dust and PM?? in this study was higher than levels recorded in other similar studies. The asbestos concentration was 0.0038 ± 0.0011 fibers/cc. This was lower than the value set by the Malaysian Department of Occupational, Safety and Health (DOSH) regulations of 0.1 fibers/cc, but higher than the background value usually recorded in indoor environments. This study strongly suggests that renovation issues need to be considered seriously by relevant stakeholders within the university in order to ensure that the associated risks toward humans and indoor environment are eliminated, or where this is not feasible, minimized as far as possible.