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This paper presents a fully RF-powered wireless transceiver integrating an efficient RF energy harvester (RFEH), a wake-up receiver (WuRx), and a wake-up transmitter (WuTx) on a single CMOS chip. The WuRx is designed to operate with supply voltages as low as 300 mV allowing to be entirely powered up by the RF energy at power levels as low as -26 dBm. The capability of the WuRx to operate without using a power management unit (PMU) enhances the sensitivity and overall conversion efficiency of RFEH system. By utilizing an ultra-low-power ultra-low-voltage envelope detector to obtain the required signal levels, using passive amplification instead of an active low-noise amplifier, and eliminating the voltage regulator removing its power overhead, the transceiver’s input sensitivity has been improved at least by a factor 2 (3 dB) compared to the other previously reported RF-powered transceivers.. The proposed transmitter consists of a fast start-up oscillator and an efficient class E power amplifier, which can be externally tuned for different output powers. Fabricated in TSMC’s 130 nm CMOS process, the measurement results show that the proposed WuRx consuming only 5.7 nW works with input powers as low as -26 dBm, and the proposed transmitter can work with input powers as low as -23 dBm. The WuTx outputs -11 dBm with 51% efficiency at 2.45 GHz using high-Q off-chip components.

This article presents a highly-efficient radio frequency energy harvester that utilizes an extra matching network to produce a passively-amplified adaptive compensation voltage. The compensation voltage produced on the gate of the transistors reduces the transistors’ conduction loss by increasing the gate-source voltage when transistors are on and reduces the leakage current by producing a negative gate-source voltage when the transistors are off. This is the first work that produces an adaptive compensation voltage without using active components, resulting in a significantly higher conversion efficiency if passive components of high quality are utilized. The mathematical derivations show that the forward conduction loss and the leakage current of the transistors are minimized by utilizing the proposed technique, increasing the overall efficiency. The proposed rectifier is fabricated in a TSMC 130 nm standard CMOS process, and measurement results and simulation results are in good agreement. Measurement results show that the rectifier achieves the maximum efficiency of 61% and 63.4% for battery load of 1.2 V and 1.5 V, respectively, which is at least 20 % larger than the efficiency of the conventional Dickson’s rectifiers.

The resistance of hospital bacterial isolates against traditional germicides, which used frequently, is one of the important factors contributing to emerging nosocomial infections. Moreover, due to having the side effects of chemical substances, the development of novel low-risk natural compounds seems necessary for control the spread of resistant pathogens in hospital environments. The aim of this study was to compare the effect of carvacrol and glutaraldehyde against two common hospital acquired pathogens, including Pseudomonas aeruginosa and Staphylococcus aureus. In this study 365 samples were collected from different wards of hospitals of Khorramabad, Iran. One hundred and sixty samples were identified as P. aeruginosa and S. aureus by using standard microbiological methods. Then the antibacterial effects of four combinations including carvacrol+ethanol, carvacrol+dimethyl sulfoxide (DMSO), glutaraldehyde 2%, and pure glutaraldehyde (50%) were evaluated and determined using dilution broth and disk diffusion methods. Our results showed that the carvacrol had more antibacterial effects against selected bacteria compared to glutaraldehyde. Moreover, the optimal time and concentration of carvacrol+ethanol against hospital isolates of P. aeruginosa and S. aureus was determined after 1 h at concentration of 64 μl/ml and 8 μl/ml, respectively. In conclusion by comparing the results of carvacrol and glutaraldehyde, seem that carvacrol, as an herbal and natural agent, may be a suitable alternative to glutaraldehyde in hospital equipment’s’ sterilization.

In this study, the concentration of fluoride in water resources and its associated health risks were investigated by collecting water samples from 43 villages around the city of Divandarreh during ...

With the rapid growth of population, development of different industries, and production of several ranges of products, the generation of municipal solid waste (MSW) has been growing significantly in the recent years. However, if MSW is not managed properly, it can greatly contribute to an environmental crisis. In the present study, we aimed to examine the characteristics and quantity of MSW generated in Iran through a meta-analysis and systematic review. The major international and Iranian national databases including Science direct, Scopus, PubMed, Google scholar, and SID and Magiran were searched completely using appropriate keywords to identify the articles that have been published from 2003 up to November 2019 on the topic on interest. Based on the inclusion criteria, a number of 13 papers were found eligible to be reviewed in this study. The results showed that the amount of generated waste per capita in Iran is 839 g/capita/day. Moreover, organic matters, paper and cardboard, plastics, glasses, textiles, rubber, polyethylene terephthalate (PET), metals (ferrous and non-ferrous), wood materials, and other wastes were found to be contributed to 65.85%, 8.79%, 8.39%, 2.73%, 2.74%, 1.18%, 1.07%, 2.83%, 1.20%, and 5.22% of total MSW in Iran, respectively. Due to the high level of organic waste in MSW stream in Iran, composting program is recommended as a practical and beneficial approach. Of note, the recyclable materials include plastic, PET, glass, metals, and paper and cardboard have accounted for 24.05% of total MSW in Iran.

This paper presents an ultra-low-power, low-voltage wake-up transmitter (WuTx) capable of transmitting two sensors’ analog output simultaneously using short pulses that their LOW and HIGH time are modulated with the analog inputs. A subthreshold relaxation oscillator along with an ultra-low-power comparator and voltage reference creates a baseband signal modulated based on two input analog signals, a ring oscillator upconverts the baseband signal to the desired transmission channel frequency (915 MHz or 2.4 GHz), and finally, an efficient Class E power amplifier with variable output power drives the antenna. The minimalist design of the proposed transmitter avoiding power-hungry data converters for sensor readout circuitry and modulation, short pulses at the output that enable the power amplifier for a short time during transmission along with the operation in the subthreshold region significantly reduces the overall power consumption. The proposed low-power and low-voltage transmitter is ideal for the long-term deployment of self-powered wireless sensors when the voltage gain and efficiency of harvesters are limited. Fabricated in a 65nm standard TSMC CMOS process, the proposed transmitter consumes a minimum of $5.41~\mu W$ average power when it is on while delivering the output power of −1dBm and $7nW$ when it is completely off.

Dye-containing wastewaters impose a serious threat to the environment. Adsorption is useful approach for decontamination of contaminated media. In this study, activated carbon prepared from stalk corn (namely SCBAC) was used for removal of Rhodamine B (RhB) from aqueous solution. The effect of pH (3–11), adsorbent dosage (0.5–2.5 g L−1), initial dye concentration (10–50 mg L−1), and contact time (30–110 min) was evaluated for RhB adsorption on SCBAC. In addition, the adsorption equilibrium was demonstrated with Langmuir and Freundlich isotherm models. Obtained results showed that the optimum pH and adsorbent dosage were 3 and 2.5 g L−1, respectively. The Freundlich isotherm model fitted well with the experimental adsorption data. The maximum adsorption capacity attained was 5.6 mg g−1. Adsorption of RhB onto adsorbent followed pseudo-second-order kinetics. Prepared SCBAC showed that can be utilized as economical and effective adsorbent for the adsorption of dyeing pollutants, like RB, from aqueous solutions.

This paper presents a systematic methodology for the co-design of matching network and rectifier of radio frequency (RF) harvesters that results in maximum power conversion efficiency (PCE) for a given available power. This method is based on our newly developed rectifier model capable of calculating the CMOS Dickson’s rectifier’s input/output voltages at a given input power developed for low/high input power regimes. The proposed model allows for the co-design of the matching network and the rectifier in a fraction of time that takes for the design of the RF energy harvester using previously developed models relying on the knowledge of rectifier’s input voltage levels where a computationally extensive iterative design procedure must be performed because of the interdependence of the rectifier’s input voltage, the input power, and the matching network’s and rectifier’s parameters. The proposed methodology is capable of accurately predicting matching network components’ sizes for both the lossless and lossy matching networks for a maximum power transfer. Utilizing the proposed methodology, the designers can produce efficiency contour plots for a given input power for finding the optimum matching network and rectifier’s parameters for maximum PCE. The model, simulation, and measurement results for different parameters and input power levels in a 130-nm process are in good agreement.

Water contamination by heavy metals has become a serious environmental issue due to its serious threat to human health. The current research was conducted to determine heavy metal concentrations in drinking groundwater samples in villages of Dehgolan, western Iran and to ascertain the potential health risk in terms of estimated non-carcinogenic risks by hazard quotient and hazard index and carcinogenic risk to the residents living in these areas from exposure to the metals via drinking water ingestion and skin contact routes. Health risks were conducted for resident adults based on the USEPA health risk assessment guidelines. The mean values of Pb, Cd, and As in the groundwater samples were 0.0026 mg/L (ranging from 0.0020–0.0030 mg/L), 0.0009 mg/L (ranging from 0.0007–0.0010 mg/L), and 0.0068 mg/L (ranging from 0.0011–0.0360 mg/L), respectively. Compared to the WHO drinking water guidelines for Pb, Cd and As, virtually all the trace elements in the drinking water of villages in the present study could meet the requirements of the regulation except As in some villages. The results of the study obtained in all cases demonstrated that the non-carcinogenic risk was below the safe limit. The calculated carcinogenic risk for adults obtained was all lower than USEPA’s acceptable cancer risk range of 1 × 10−4 to 1 × 10−6, suggesting no potential carcinogenic risk from drinking water consumption.

In the catalytic ozonation process used in this study, adsorption and chemical reactions were performed at the catalyst surface. This process can increase the efficiency of plain ozonation. The main aim of this study was to investigate the efficiency of the catalytic ozonation process in removing Alizarin Red S dye from colored water by Fe2O3 coated on PAC. In this work, activated carbon powder/γ-Fe2O3 nano-composite was modified. The BET results showed that the surface area in PAC and PAC-γ-Fe2O3 nano-composite was 654 and 450 m2 g−1, respectively. In this study, the best pH for removal of ARS was found to be 9. At a higher pH, the efficiency of the process decreased gradually. According to studies, catalysts increase surface area and active sites for more ozone degradation. Also, the characterization of the catalyst will play a very important role in the COP. Also, the maximum removal efficiency was observed in catalyst dose 1.1 g l−1. The study results showed that the highest mineralization rat...

Background Based on the cross-sectional and cohort studies, exposure to As via drinking water can cause hypertension. Methods We searched PubMed, ISI WOS, and Scopus for relevant studies up to 1 January 2018 using related keywords. The meta-analysis was done on 10 studies (n = 28255) that report Odds Ratio for hypertension. The extracted ORs between As concentration and hypertension were pooled using random effect models. Study heterogeneity was analyzed using I2. Results The estimated adjusted OR for association between As and hypertension was 1.44 (95% CI: 1.12, 1.84) with I2 = 71%. Dose-Response analysis showed a linear relationship between As and hypertension (OR = 1.0008 95% CI: 1.0003, 1.001). In general, by increase of each unit in arsenic concentration, odds of the hypertension would increase as 0.08%. Conclusion There was a significant relationship between As exposure and hypertension., Arsenic, Meta-analysis, Health risk, Chronic exposure, Drinking water

Three types of adsorbents of powdered activated carbon (PAC), treated PAC, and PAC/γ ≈ Fe2O3 nanocomposite were used. The adsorption experiments were performed in batch conditions. pHZPC of PAC/γ ≈ Fe2O3 was 6.7. As a result, at lower than pHZPC, acidic pH, the adsorption of alizarin red S on PAC/γ ≈ Fe2O3 was favourable. The maximum of alizarin red S adsorption of PAC, treated PAC, and PAC/γ ≈ Fe2O3 was 24.5 mg/g, 57.8 mg/g, and 112.56 mg/g, respectively. The models of Langmuir and pseudo-first-order were a fit model to describe the adsorption isotherm and the Kinetic, respectively. The PAC/γ ≈ Fe2O3 is a promising class of the adsorbents in the adsorption of various dyes from textile effluents. Keywords: Adsorption, Textile effluents, Dye, Aqueous solutions, Fe2O3

Nowadays in many countries, air pollution is one of the major issues affecting human health. Among the various air pollutants particulate matters are mainly present in ambient air pollution. The purpose of this study was to measure the concentration of particulate matter (PM) (namely PM2.5 and PM10) and to conduct zoning via GIS software in Khorramabad city (Summer – 2017). According to the findings, the average concentrations of PM2.5 in July, August and September were 100.1, 116.3, and 199.8 μg/m3, respectively. Furthermore, the average concentrations of PM10 in July, August and September were 199.8, 215.7, and 190.8 μg/m3, respectively. The findings of this study also indicated that due to continuous dust storms,particularly in recent years, the air pollution status in Khorramabad was not suitable that can adversely affect public health. Keywords: Air quality index, PM10, PM2.5, Khorramabad, GIS

The variables examined were initial fluoride concentration, ZIF-8 and Uio-66 dosage, pH, and contact time. The residual concentration of fluoride was measured by a spectrophotometer. According to BET, the specific surface area of the ZIF-8 and Uio-66 was 1050 m2/g and 800 m2/g, respectively. Total pore volume and average pore diameter of the ZIF-8 and Uio-66 were 0.57 cm3/g, 0.45 cm3/g and 4.5 nm, 3.2 nm, respectively. The best pH for fluoride adsorption was neutral conditions. By increasing the ZIF-8 and Uio-66 dose, the fluoride uptake increased at first, but then decreased. Also, the maximum adsorption for ZIF-8 and Uio-66 was observed in adsorbent dose 0.2 and 0.6 g/L, respectively. The best model for describing kinetic and isotherms of fluoride adsorption were the pseudo-second-order model and Langmuir isotherm model, respectively. Based on the Langmuir model, the adsorption capacity of fluoride by ZIF-8 and Uio-66 was reported to be 25 mg/g and 20 mg/g, respectively. Keywords: Fluoride, Aqueous solution, Adsorption, Metal-organic framework

Good quality of drinking water is very important in the maintenance of human health. The gathered data from the present work was used to evaluate the quality of drinking water resources in the rural villages of Divandarreh, Iran. Physicochemical quality of water was determined by a collection of 35 random samples during dry and rainy seasons in 2015. The APHA approach was used to determine the physicochemical parameters of the samples. The results showed that the average concentration of Ca, Mg, Na, K, Cl, SO4, TDS and TH during dry season was 85.64 mg/l, 13.41 mg/l, 34.11 mg/l, 2.8 mg/l, 9.9 mg/l, 45.7 mg/l, 326.06 mg/l and 269.61 mg/l, respectively. Also, the average concentration of the parameters during rainy season was 77.3 mg/l, 18.27 mg/l, 30.3 mg/l, 1.9 mg/l, 12.54 mg/l, 39 mg/l, 269.1 mg/l and 316.17 mg/l, respectively. Keywords: Divandarreh, Physicochemical quality, Drinking water, Rural area

Contamination of environment, especially soil, is in great concern and can cause health problems. Thus, remediation of these pollutants through environmentally friendly methods should be considered. The aim of this data was bioremediation of TNT from contaminated soil. Two plastic pans were used as bioreactor. In each pan, 3 kg of soil was used. Concentration of TNT in contaminated soil was 1000 mg/kg. Rhamnolipid in concentration of 60 mg/l was added to intended pan. Sampling was done in each two weeks. In order to assessment of TNT degradation, samples were analyzed with HPLC. The data showed that after 154 days of experiment, TNT removal in soil that amended with rhamnolipid was 73% and in experiment with no addition of rhamnolipid was 58%. Based on the obtained data rhamnolipid was effective in remediation of TNT contaminated soil. Keywords: TNT, Soil contamination, Rhamnolipid, Bioremediation, Soil

Pharmaceutical products, particularly antibiotics, due to their cumulative characteristics, undesirable effects and creating drug resistances, as inevitably pollutants, poses a major concern in environmental issues. In recent years, advanced oxidation processes (AOP) have been considerably used for degradation of new and emerging pollutants such as residual medications and resistant compounds in water and wastewater. Present investigation evaluates the removal of metronidazole from aqueous solution by electro coagulation and photoelectrophenton processes. The data will be informative for environmental agencies, pharmaceutical companies and wastewater treatment companies for choosing it as a practical oxidation advance process for treatment of water polluted by resistant material (drugs and pesticides).

The concentration of fluoride and nitrate in groundwater is usually higher than that of surface water. The main objective of this study was to estimate the health-risk assessment associated with fl...

Continuous monitoring of drinking water quality is essential in terms of heavy metals and toxic substances. The general objective of this study were to determine the concentration of heavy metals in drinking water of Khorramabad city and to determine the water quality indices (The heavy metal pollution index and heavy metal evaluation index). According to the city map, 45 points were selected for drinking water sampling through the city distribution system. The results of this study showed that the average concentration of heavy metals such as Zn, Pb, Cd, Cr, and Cu were 47.01 μg/l, 3.2 μg/l, 0.42 μg/l, 5.08 μg/l, and 6.79 μg/l, respectively. The HPI and HEI (water quality indices) for Zn, Pb, Cd, Cr, and Cu were 46.58, 46.58, respectively. According to the indices, the city drinking water quality is good in terms of heavy metals. Keywords: Drinking water quality, Heavy metals, Monitoring, Khorramabad city

Background: Cleanup of areas contaminated by explosives is a public health concern. Some explosives can be carcinogenic in humans. Pentaerythritol Tetranitrate (PETN), a powerful explosive with very low water solubility, can be easily transported to ground waters. Objective: This study was conducted to determine the removal efficiencies of PETN from soil by bioremediation, and obtain kinetic parameters of biological process. Methods: This experimental study was conducted at the Environmental Health Engineering Lab (Isfahan University of Medical Sciences, Isfahan, Iran) in 2015-2016. In the present work, bioremediation of the explosive-polluted soils by PETN in anaerobic-aerobic landfarming method was performed. The influence of seeding and biosurfactant addition on bioremediation was also evaluated. The data were analyzed using Microsoft Excel software. Results: The results show that, as the initial concentration of PETN increased, the lag phase was increased and the specific growth rate was increased up to 0.1/day in concentration of 50 mg/kg, and then it was decreased to 0.04/day. Subsequent decreases in specific growth rate can cause substrate inhibition. Seeding causes decrease in lag phase significantly. Biosurfactant addition had little to no impact on the length of lag phase, but biosurfactant plus seeding can increase the growth rate to 0.2/day, however, inhibitory effect of the initial concentration was started in very high concentration of PETN (150 mg/kg). Conclusion: Biosurfactant addition and seeding together have an impressive effect on biodegradation of PETN, furthermore seeding can enhance active microbial consortium and biosurfactant can improve the poor aqueous solubility of PETN, therefore making the substrate more accessible.

Background: Air Quality software is a useful tool for assessing the health risks associated with air pollutants. Quantifying the effects of exposure to air pollutants in terms of public health has become a critical component of policy discussion. The present study purposed to quantify the health effects of particulate matters on mortality and morbidity in a Bukan city hospital from 2015-2016. Methods: Information regarding coordinates, exposed population, number of stations used in profiling, mean and maximum concentrations (annual, winter, and summer), annual 98th percentile, baseline incidence (BI) per 100 000 per year, and relative risk was needed for use with the software. Results: The average particulate matter concentration was higher in summer than in winter. The concentrations of PM10 in summer and winter were 84.37 and 74.86 μg m-3, respectively. The Air Quality model predicted that total mortality rates related to PM10 and PM2.5 were 33.3 and 49.8 deaths, respectively. As a result, 3.79% of the total mortality was due to PM10. In Bukan city, 2.004% of total deaths were due to cardiovascular mortality. The Air Quality model predicted that the deaths of 92.2 people were related to hospital admissions for respiratory disease. Conclusion: The continual evaluation of air quality data is necessary for investigating the effect of pollutants on human health.

The aim of this study was to investigate the bioremediation of two explosives 2, 4, 6-trinitrotoluene (TNT) and Pentaerythritol Tetranitrate (PETN) in mixture by aerobic process. Microbial inocula were obtained from a textile wastewater treatment plant activated sludge. Addition of rhamnolipid surfactant (60 mg/l) increased the removal efficiencies of TNT and PETN from 53% and 57% to 98% and 91%, respectively. Explosives degradation reaction is expressed to be of first-order and the kinetic reaction parameters are calculated based on different initial concentrations of TNT and PETN. The first-order rate constants of the rhamnolipid amended experiments were at least 3 orders and 2.5 orders of magnitude higher for TNT and PETN, respectively, than those found for not amended rhamnolipid experiments. The metabolites pentaerythritoldinitrate, 3-hydroxy-2,2-bis [(nitrooxy) methyl] propanal, and2,2-bis-[(nitrooxy) methyl]-propanedialfor PETN and2-amino-4, 6dinitrotoluene and 4-amino-2, 6-dinitrotoluene for TNT were identified by LC-MS. Concomitant degradation of TNT and PETN resulted in decrease of environment pH. Inoculated bacteria have capability to use of explosive as source of nitrogen and energy. It seems that the addition of rhamnolipid showed great potential for treatment of explosives by textile activated sludge. Keywords Author Keywords:TNT; PETN; rhamnolipid; textile activated sludge KeyWords Plus:PENTAERYTHRITOL TETRANITRATE PETN; DEGRADATION; 2,4,6-TRINITROTOLUENE; BIOREMEDIATION; BIOSURFACTANTS; MINERALIZATION

The resistance of hospital bacterial isolates against traditional germicides, which used frequently, is one of the important factors contributing to emerging nosocomial infections. Moreover, due to having the side effects of chemical substances, the development of novel low-risk natural compounds seems necessary for control the spread of resistant pathogens in hospital environments. The aim of this study was to compare the effect of carvacrol and glutaraldehyde against two common hospital acquired pathogens, including Pseudomonas aeruginosa and Staphylococcus aureus. In this study 365 samples were collected from different wards of hospitals of Khorramabad, Iran. One hundred and sixty samples were identified as P. aeruginosa and S. aureus by using standard microbiological methods. Then the antibacterial effects of four combinations including carvacrol+ethanol, carvacrol+dimethyl sulfoxide (DMSO), glutaraldehyde 2%, and pure glutaraldehyde (50%) were evaluated and determined using dilution broth and disk diffusion methods. Our results showed that the carvacrol had more antibacterial effects against selected bacteria compared to glutaraldehyde. Moreover, the optimal time and concentration of carvacrol+ethanol against hospital isolates of P. aeruginosa and S. aureus was determined after 1 h at concentration of 64 μl/ml and 8 μl/ml, respectively. In conclusion by comparing the results of carvacrol and glutaraldehyde, seem that carvacrol, as an herbal and natural agent, may be a suitable alternative to glutaraldehyde in hospital equipment’s’ sterilization.

The dynamics of tornadolike vortices is investigated through a set of novel physical experiments and modal analyses for a wide range of swirl ratios (0.22 ≤ S ≤ 0.96). Various physical phenomena such as wandering, vortex breakdown, or transition from one-cell to two-cell structures are observed. To investigate the coherent structure of the tornado vortices, two different decomposition methods are applied: (i) proper orthogonal decomposition (POD), also referred to as principle component analysis, and (ii) a novel dynamic proper orthogonal decomposition to provide time evolutions of the POD modes. To foster the physical interpretation of these POD modes, we also applied modal decomposition on a simulated synthetic vortex. The results show that at low swirl ratios before vortex breakdown, the flow is characterized by a single vortex which is tilted at lower heights. For intermediate swirls, before vortex touchdown, the flow is characterized by a recirculation bubble with a single spiral rotating around it. By further increasing the swirl ratio, transition from a single spiral to a double spiral (one-cell to two-cell structures) occurs. Based on these observations, a simple vortex structure of tornadolike vortex is put forward which can be used to generate a low order, large scale turbulence model for these types of flows.

Nonlinear contact between tip and sample in tapping mode atomic force microscopy (AFM) systems induces higher harmonics, which may be useful for extraction of some characteristics of the sample. In this paper, a new efficient method for implementing multichannel digital lock-in technique is presented, which is able to measure the amplitude and phase of multiple modulated frequency signals. In order to solve the two most important problems in AFM systems, which are resolution and cost, previous multichannel lock-in amplifier methods are investigated and an improved algorithm for amplitude and phase extraction using fast Fourier transform is developed. In addition, we propose a novel multichannel digital lock-in algorithm including an $N$ -slow digital filter and a multichannel direct digital synthesis block for generating reference signals. We achieve optimal noise reduction using the appropriate decimation filters prior to harmonic extraction. This modification results in a significant hardware reduction in implementation compared with classical designs. Since the precision of the design is sensitive to the sampling frequency, we perform the suitable sampling rate conversion using fractional delay and decimation filters, which enhance the accuracy and noise resiliency of the designed architectures. Experimental results prove the efficiency of the proposed method in multiple modulated frequencies extraction. Also, FPGA implementation results show that the proposed architecture is superior to previous structures, especially in the aspect of area.

Surface pressure measurement is a general tool for evaluating wind flow qualitatively and quantitatively. Due to its complex temporal and spatial features, modal analysis is an interesting tool to be used for interpretation and discussion. The most common technique for modal representation is proper orthogonal decomposition (POD), also referred to as principal component analysis. However, it is believed that POD sometimes fails to extract meaningful features of the pressure field. To remove the non-physical POD modes and provide a closer physical description of the pressure field, an advanced method independent component analysis (ICA) is applied. Furthermore, these two methods are generalized in the frequency domain, called dynamic POD and dynamic ICA, to provide the temporal evolutions of coherent structures over the spatial domain. Modal analysis is used to isolate the different coherent structures in tornado-like vortices, e.g., wandering, vortex breakdown, and two-cell structure, and find the spectral characteristic of each phenomenon. Moreover, a comparison of modal analysis between the current paper and the previous paper on the velocity field {see Karami et al., [“Coherent structures in tornado-like vortices,” Phys. Fluids 31, 085118 (2019)]} presents new insight into the pressure–velocity correlation of the POD modes.

The sorption of As(V) on manganese oxide coated zeolite (MOCZ) was investigated through batch study to explore the feasibility of removing arsenic from groundwater. MOCZ was characterized by scanning electron microscopy, XRD, FTIR spectroscopy, and point of zero charge (pH PZC ) measurements. The effects of process parameters such as contact time, adsorbent size, temperature and pH were investigated. Arsenic detection was carried out by atomic fluorescence spectrometer. Arsenate adsorption onto MOCZ followed the pseudo-second-order kinetic model with a correlation coefficient more than 0.99. Optimum removal of arsenate occurred within pH range of 6–10. The equilibrium data were analyzed by Langmuir, Freundlich and Dubinin-Radushkevich (D-R) isotherm models. The maximum adsorption capacity calculated from the Langmuir and D-R models was 151 and 152.8 μg g−1, respectively, at 38 °C. The activation energy of adsorption (E a ) was found to be 3.68 kj mol−1, suggesting that the adsorption process may be physical sorption. Thermodynamic parameters: ΔH o , was 1.181 kj mol−1; ΔS o , was −0.29 kj mol−1, while the values of ΔG o were −83.9, −86.7 and 89.8 kj mol−1 at 18, 28 and 38, respectively, suggesting endothermic and spontaneous process and a rise in temperature favoring the adsorption.

This study was performed to evaluate formaldehyde degradation ratio in a batch reactor. For investigation of the synergism effect, formaldehyde degradation by each process (UV photolysis, ZnO catalyst, ultrasonic wave) was tested. In the next step, the influence of important operational parameters, such as pH of the solution (3–8), initial CH2O concentration (20–100 mg/l), dosage of nZnO (10–60 mg/l), ultrasonic wave power (40–150 W), and reaction time (10–60 min) was investigated. Ultrasonic wave process could slightly degrade CH2O and had a partial effect as synergism on formaldehyde degradation. Maximum formaldehyde removal ratio occurred with a nZnO dosage of 60 mg/l, pH of the solution of 8, ultrasonic wave power of 40 W, and initial formaldehyde concentration of 50 mg/l with a contact time of 30 min (78%). A comparison of the reaction orders of kinetic studies showed that formaldehyde degradation was in accordance with pseudo-second-order reaction. It could be found that the sonophotocatalyt...

At least 90% of the research on bioremediation has been based on the use of materials in cometabolism and/or as electron donors. The main purpose of this study was to evaluate biodegradatio...

Excessive intake of fluoride can cause adverse health effects. Consumption of tea as a popular drink could be a potential source of fluoride exposure to humans. This research aimed to evaluate the fluoride concentration in tea among the Iranian people using the available data in the literature and to assess the health risk related to the consumption of tea in men, women, and children. The health risk assessment was conducted using the chronic daily intake and hazard quotient according to the approach suggested by the Environmental Protection Agency. The fluoride content in published studies varied noticeably, ranging from 0.13 to 3.27 mg/L. The results revealed that the hazard quotient (HQ) in age groups of women (21&ndash, 72 years) and children (0&ndash, 11 years) was within the safe zone (HQ &lt, 1) which showed that there was no potential of non-carcinogenic risk associated with drinking tea in these groups. However, in one case of the men (21&ndash, 72 years), the HQ &gt, 1 which shows a probable risk of fluorosis. The order of non-carcinogenic health risks in the studied groups was in the order of men &gt, women &gt, children. The results of this can be useful for organizations with the responsibility of human health promotion.