Control charts are an important statistical process control tool used to monitor changes in process location and variability. This study addresses issues regarding the proper choice of control chart for efficient monitoring of process variability. The choice of the best estimator to be used for variability charts has not been made clear in literature. We have analyzed the performance of eight control chart structures, based on different estimates of process standard deviation. The performance of control charts is investigated under the existence and violation of ideal assumptions of normality. Control chart constants and factors required for computing probability limits, considering normal and different non‐normal parent distributions, are provided for all variability charts. This study aims at providing guidance to quality practitioners in choosing the appropriate variability control chart for normal and non‐normal processes. Copyright © 2011 John Wiley & Sons, Ltd.

We report the synthesis of MnO nanoparticles (AI-MnO NAPs) using biological molecules of Abutilon indicum leaf extract. Further, they were evaluated for antibacterial and cytotoxicity activity against different pathogenic microbes (Escherichia coli, Bordetella bronchiseptica, Staphylococcus aureus, and Bacillus subtilis) and HeLa cancerous cells. Synthesized NAPs were also investigated for photocatalytic dye degradation potential against methylene blue (MB), and adsorption activity against Cr(VI) was also determined. Results from Scanning electron microscope (SEM), X-ray powder diffraction (XRD), Energy-dispersive X-ray (EDX), and Fourier-transform infrared spectroscopy (FTIR) confirmed the successful synthesis of NAPs with spherical morphology and crystalline nature. Biological activity results demonstrated that synthesized AI-MnO NAPs exhibited significant antibacterial and cytotoxicity propensities against pathogenic microbes and cancerous cells, respectively, compared with plant extract. Moreover, synthesized AI-MnO NAPs demonstrated the comparable biological activities results to standard drugs. These excellent biological activities results are attributed to the existence of the plant’s biological molecules on their surfaces and small particle size (synergetic effect). Synthesized NAPs displayed better MB-photocatalyzing properties under sunlight than an ultraviolet lamp. The Cr(VI) adsorption result showed that synthesized NAPs efficiently adsorbed more Cr(VI) at higher acidic pH than at basic pH. Hence, the current findings suggest that Abutilon indicum is a valuable source for tailoring the potential of NAPs toward various enhanced biological, photocatalytic, and adsorption activities. Consequently, the plant’s biological molecule-mediated synthesized AI-MnO NAPs could be excellent contenders for future therapeutic applications.

Face masks are primary line of defense to reduce the transmission risk of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). World Health Organization (WHO) has already updated the guidelines and advised the use of face masks in public areas essentially. This has dramatically increased the production and use of face masks in many parts of the world. Arabian Peninsula is comprised of six countries where the public perception of following WHO guidelines is high. In this study, we highlight the concerns relating to extensive use of face masks in this region, particularly in the context of (micro-)plastic pollution. We computed the number of face masks to be used in each of the countries of Arabian Peninsula for varying levels of acceptance rate and average number of daily usages. Accordingly, the amount of (micro-)plastic that could come into the terrestrial and marine environment is also reported. Saudi Arabia, being the most populated country in the region may contribute up to 32–235 thousand tons of (micro-)plastic which is nearly half of the amount in the whole Peninsula. On the other hand, an extremely high infection rate in Qatar (25.74%) may also lead to a significant increase of (micro-)plastic content due to high public acceptance rate and living standards. The high (micro-)plastic fraction is of significant concern because it ends up in the marine ecosystems. Further, it allows colonization of several pathogenic microorganisms (bacteria, viruses, fungal filaments, and spores) and might serve as carriers of disease transmission finally affecting the living organisms habituating these ecosystems. It is suggested that appropriate regulations on face masks waste should be devised to avoid any unwanted consequences in the near future.

Control chart is the most important statistical process control tool used to monitor changes in process location and dispersion. In this study, an EWMA control chart is proposed for efficient and robust monitoring of process dispersion. The proposed chart, namely the MDEWMA chart, is based on estimating the process standard deviation (σ ) using the mean absolute deviations (MD), taken from the sample median. The performance of the proposed chart has been compared with the EWMASR chart (a dispersion EWMA chart based on sample range) and MD chart (a Shewhart-type dispersion chart based on MD), under the existence and violation of normality assumption. It has been observed that the proposed MDEWMA chart is more efficient and robust when compared with both EWMASR and MD charts in terms of run length (RL) characteristics such as average RL, median RL and standard deviation of the RL distribution.

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