Pattern of disinfectants use and their adverse effects on the consumers after COVID-19 outbreak

Background and objective: The aim of this study was to investigate the pattern of disinfectants use within outbreak of COVID-19 and estimate their adverse effects on the consumer�s health. Methods: In this descriptive-analytical study, 1090 participants were entered into the study without age and gender limitations. A researcher-made electronic checklist containing 43 questions was applied to collect data. The checklist included three sections: demographic characteristics (8 questions), disinfection of body and non-living surfaces (21 questions), and adverse effects of disinfectants on health (15 questions). Results: 87 of participants used the incorrect proportions of water and alcohol to make this disinfectant available at home. The percentage of people with wrong proportion of sodium hypochlorite was 74.2. Approximately 42 of participants experienced at least one disorder on their hands, feet, eyes, respiratory or gastrointestinal systems after sequential uses of disinfectants. The most common disorders among the participants were found to be skin dryness (76.3), obsession (42.2), skin itching (41.2), coughing (41.1), and eyes irritation (39.5). The mean frequency of hand washing and hand disinfecting were 15.28 and 10.74 times per a day, respectively, and the clean-up in case of surfaces was 2.99 times a day. The frequency of hand washing and disinfecting in women group (16.4 and 11.2 times a day) were higher than in men (14.0 and 10.3 times a day) group. In addition, these self-care actions in married people (15.6 and 11.0 times a day) were higher compared to those in single people (14.0 and 10.6 times a day). Conclusion: Being unaware of participants with instruction for preparation and use disinfectants may harm their health. Therefore, it is suggested that the authorities provide the necessary training program for public through official media. © 2020, Springer Nature Switzerland AG

Optimization of metal working fluids treatment using calcium chloride by response surface methodology

Background: Extensive use of metal working fluids degrades their chemical composition. They should be treated using a safe method. Chemical coagulation-flocculation process is one the treatment methods. Objective: The aim of this study was to optimize the coagulation-flocculation process using calcium chloride in metal working fluids treatment. Methods: This laboratory based study was performed in School of Health affiliated to Qazvin University of Medical Sciences in 2014. Using calcium chloride and a six-compartment jar, the efficiency of coagulation-flocculation process was assessed for removal of chemical oxygen demand (COD) and turbidity and amount of released oil. Central composite design (CCD) and response surface methodology (RSM) were applied to optimize the treatment operation parameters (pH and dosage of coagulant). Quadratic models were developed for calculation of the three responses (COD, turbidity, and released oil). Findings: The optimum condition for coagulation-flocculation process was seen after treatment with 4.2 g/L calcium chloride at pH 3.71 in which COD and turbidity removal efficiency were 93% and 96.9%, respectively and the amount of released oil was 31.8 ml. The level of desirability was 91.2%. The values of laboratory study were in good agreement with the values predicted by the model. Conclusion: Metal working fluids treatment with calcium chloride was efficient in the removal of pollution parameters. Dosage of calcium chloride was similar to the conventional coagulants such as Alum, but its efficiency was higher. Keywords: Treatment, Metal Working Fluid, Flocculation, Calcium Chloride, Response Surface Methodolog

Determination Effective Dose of Radon 222 in the Packaged Drinking Water in Various age Groups Tehran, Iran

Background: Radon 222 is a natural radioactive material with a half-life of 3.8 days, colorless and odorless. Consumption of water containing high concentration of Radon 222 leads to increase in the effective dose received in different age groups and following that increase in the prevalence of gastric cancer. Material and Methods: In this descriptive cross-sectional study, concentration of Radon 222 of 17 packaged widely-consumed water in Tehran city was measured by portable Radon detector RTM1688-2 model. Also the received effective dose by the group ages of adult men and women, children and infants was calculated through the provided equation of UNSCEAR. Results: The mean and range concentration of Radon 222 was 69.6±0.58 Bq/m3 and 0 – 458.6±5.3 Bq/m3, respectively. The received effective dose by the age groups of infants, children, adult men and women was 0009, 0.004, 0.006 and 0.008 mSv/y, respectively. Conclusion: The mean concentration of Radon 222 is lower than WHO and EPA standard limits. The arrangement of the received effective dose in different age groups is infants>adult men>adult women>children. The received effective doses of Radon 222 in all age groups especially infants and adult men was lower than the of 0.1 mSv/y standard limit

Optimization of metal working fluids treatment using calcium chloride by response surface methodology

Background: Extensive use of metal working fluids degrades their chemical composition. They should be treated using a safe method. Chemical coagulation-flocculation process is one the treatment methods. Objective: The aim of this study was to optimize the coagulation-flocculation process using calcium chloride in metal working fluids treatment. Methods: This laboratory based study was performed in School of Health affiliated to Qazvin University of Medical Sciences in 2014. Using calcium chloride and a six-compartment jar, the efficiency of coagulation-flocculation process was assessed for removal of chemical oxygen demand (COD) and turbidity and amount of released oil. Central composite design (CCD) and response surface methodology (RSM) were applied to optimize the treatment operation parameters (pH and dosage of coagulant). Quadratic models were developed for calculation of the three responses (COD, turbidity, and released oil). Findings: The optimum condition for coagulation-flocculation process was seen after treatment with 4.2 g/L calcium chloride at pH 3.71 in which COD and turbidity removal efficiency were 93% and 96.9%, respectively and the amount of released oil was 31.8 ml. The level of desirability was 91.2%. The values of laboratory study were in good agreement with the values predicted by the model. Conclusion: Metal working fluids treatment with calcium chloride was efficient in the removal of pollution parameters. Dosage of calcium chloride was similar to the conventional coagulants such as Alum, but its efficiency was higher

Preparation, characterization and Cr(VI) adsorption evaluation of NaOH-activated carbon produced from Date Press Cake; an agro-industrial waste

Date Press Cake (DPC) is an inevitable by-product of date processing industries and may pose environmental problems if not managed properly. In this study, DPC was converted into activated carbon using solid NaOH under various activation conditions. The prepared activated carbon showed high specific surface area (2025.9 m(2) g(-1)) and microporous texture (86.01). It was successfully applied for the adsorption of Cr(VI) from aqueous solutions with maximum monolayer adsorption capacities as high as 282.8 mg g(-1) (pH = 2) and 198.0 mg g(-1) (pH = 5). The kinetic and isotherm experimental data of Cr(VI) adsorption onto the activated carbon were best described by Elovich and Redlich-Peterson models, respectively. It was found that the Cr(VI) adsorption onto the DPC-derived activated carbon was predominantly a chemisorption process with limited desorption rates (below 50). Overall, Date Press Cake could be considered as an abundant and renewable agroindustrial precursor for the production of high quality activated carbon

Enhanced K-Nearest Neighbors Method Application in Case of Draglines Reliability Analysis

Dragline’s availability plays a major role in sustaining economicfeasibility and operation of opencast coal mine. Thus, its reliability is essentialfor the production availability of mine. The dragline’s reliability and maintenanceoptimization are key issues, which should seriously be considered. Draglines’unexpected failures and consequently unavailability result in delayed productionsand increased maintenance and operating costs. The applications ofmethodologies which can predict the failure mode of dragline based on thehistorical dataset of failure are not only useful to reduce the maintenance andoperating costs but also increase the availability and the production rate of miningmachineries. In this research a historical failure dataset of a dragline has beenutilized in order to analyze and conduct predictive maintenance. Authors havealready utilized the K-Nearest Neighbors (KNN) algorithm in order to predict thefailure mode; however, there was a chance of getting into local optimum byutilization of the mentioned methodology. In this case, combination of GeneticAlgorithm and K-Nearest Neighbor algorithm (i.e. called enhanced K-NearestNeighbors) was applied for the failure dataset, so the probability of localoptimum has been decreased by application of Genetic Algorithm. In previousstudies, the Artificial Neural Network methods and conventional method of KNearestNeighbor has been applied to the same dataset, yet the result fromenhanced K-Nearest Neighbor reveals better regression analysis.ISBN för värdpublikation: 978-3-319-99219-8, 978-3-319-99220-4</p