afsaneh maleki

This study investigated the efficiency of membrane polyetheretherketone/polyetherimide modified with magnesium oxide nanoparticles to remove xylene and toluene from the air with gas chromatography. The influence of effective parameters such as sorbent dosage, extraction time, and extraction temperature of the sample was investigated and the optimum conditions were chosen. Various techniques including FT-IR, XRD, EDX, and SEM, were used to characterize this membrane. To optimize adsorption efficiency, factors such as xylene and toluene concentration, adsorbent dosage, temperature, and contact time were carefully fine-tuned. It was found that 50 mg of membranes has the best adsorption efficiency for both pollutants. The maximum adsorption capacities were found to be 163 mg/g for xylene and 200 mg/g for toluene on the PEEK/PEI nanocomposite adsorbent. Moreover, 190 mg/g for xylene and 230 mg/g for toluene were observed on the PEEK/PEI membrane modified with MgO nanoparticles. These results clearly demonstrate that PEEK/PEI membrane modified with MgO nanoparticles is a highly efficient adsorbent for eliminating xylene and toluene from air, making it a promising solution for air quality purification and environmental remediation applications.

The oil and gas industry is facing a critical challenge with the growing emissions of flare gases, driven by the global expansion of the industry and increased fossil fuel consumption in refineries and petrochemical plants. The significant environmental impact of these flare gas emissions has created a pressing need to develop effective strategies to minimize the associated environmental risks. However, implementing technologies to reduce flare gas emissions presents both economic and environmental hurdles.
In this study, we investigated the application of nanoadsorbents in packed bed towers as a promising approach to recover and repurpose flare gases. Using MATLAB software, we conducted two case studies to evaluate the performance of different adsorbent materials, including Ws and H silica gels, as well as a 4 Å molecular sieve, for the recovery and conversion of sour flare gas into sweet, moist gas. The analysis revealed that the Langmuir isotherm model provided the most suitable simulation results, demonstrating the technical feasibility and effectiveness of this approach.

Activated carbon from the walnut shell modified by sepiolite (AC/SEP) composite was synthesized and applied for the adsorption of toxic lead (Pb(II)) ions from industrial effluents.  AC/SEP composite was characterized by Fourier Transform InfraRed (FT-IR) spectrometer, Field Emission Scanning Electron Microscopy (FESEM), Brunauer–Emmett–Teller (BET), and X-Ray Diffraction (XRD) analyses. Effects of pH, amount of adsorbent, Lead initial concentration, and contact time on removal percentage were studied by Central Composite Design  (CCD). The optimal condition for maximum Lead removal by AC/SEP adsorbent (99.07%) was as follows: pH= 5.00, adsorbent amount: 0.05 g, initial concentration 20.00 mg/L, and contact time: 25.00 min in 10 mL of pollutant volume. Also, the adsorption kinetics, thermodynamics, and isotherms were determined. Adsorption isotherms (qmax: 269.67 mg/g) and kinetics showed that the sorption process was better modeled by the Langmuir and pseudo-second-order equation.

In the current study, an in-depth examination was conducted to evaluate how the particle size of titanium dioxide (TiO2) will affect the mechanical, thermal, and morphological properties of the modified Pebax/TiO2 nanoparticle membrane. TiO2 nanoparticles were initially modified with amino silane and then incorporated into the nanocomposite Pebax/TiO2 membrane. The obtained membranes were characterized by FT-IR, SEM, TEM, TGA, and XRD to assess the effect of modification. The result of membrane performance evaluation indicated that the solubility of the gas molecules increased within the polymer matrix when an increase in CO2 permeability was observed. To test the performance of the nanocomposite membrane in the high-pressure separation process, the feed pressure was increased from 2 to 10 bar and the results demonstrated that the CO2/CH4 selectivity boosted from 16.05 to 97.74, respectively. Furthermore, when the surface of TiO2 nanoparticles was modified by amino silane and its concentration increased in the polymer matrix, the CO2 permeability of the nanocomposite membrane increased from 87.12 to 24.71 compared to that of the pure Pebax membrane. Experimental data were correlated with ANN (artificial neural network. The ANN of the model applied in this study includes the Levenberg-Marquardt algorithm, purelin or a linear transfer function at the output layer, and tansig or a tangent sigmoid transfer function in the hidden layer with 5 neurons.

In recent years, interest in the synthesis and use of boron-nitride (BN) structures has increased due to their distinct properties. These properties include low density, high-temperature stability, oxidation resistance, high dispersion stability, high shear force (compared to its equivalent structure, graphene), high absorption capacity, and wide bandwidth. In this study, using the Density Functional Theory (DFT), the effect of the Electric Field (EF) on Na and Na + adsorption on BN nanosheets as the anode in sodium batteries was investigated. The results showed that Na+ adsorption was much stronger than Na and the cell voltage (Vcell) increased linearly with increasing electric field. In the absence of a field, Vcell = 1 / 13V, it increases by increasing the field to Vcell = 1 / 87V, which results in high energy storage in a long discharge battery.

The identification of the factors related to adoption of skin cancer preventive behaviors in adolescents plays a significant role in the appropriate design and implementation of relevant educational approaches. The aim of present study was toinvestigate the factors associated with skin cancer preventive behaviors in the male high school students of Isfahan, using the protection motivation theory (PMT). This descriptive cross-sectional study was conducted on 311 male high school students of Isfahan in 2018. A reliable questionnaire was used for data collection, whose validity and reliability had been confirmed before. The data were analyzed, using the SPSS software (version 20), Pearson’s correlation coefficient, multiple linear regression, one-way ANOVA, independent t test, and Spearman’s correlation coefficient. Pearson’s correlation coefficient indicated that the score of skin cancer preventive behaviors was inversely associated with response cost score (P < 0.001), while it was directly related to perceived susceptibility, perceived severity, self-efficacy, response efficacy, fear, and protection motivation (P < 0.001). The multiple linear regression model showed that among the constructs of the PMT, the scores for self-efficacy, response cost, and perceived susceptibility were significant predictors of skin cancer preventive behaviors, respectively, in order of importance. This study showed that the PMT constructs were associated with the skin cancer preventive behaviors, which could be promoted by designing and implementing educational studies based on the constructs

Physicians play a key role in the effectiveness of the health system in each country. Providing favorable job conditions for physicians, including appropriate payment system increase the quality of medical services. The aim of this study was to compare general physicians’ (GP) income and taxation system in Iran and other countries. In this study, GP's income in Iran and 16 other countries was compared with per capita income in these countries. Data was extracted from peer reviewed literatures and reliable websites. Sources for GP's income in Iran were Guideline of Family Physician Program and Referral System in Urban Areas, Version 02 and Guideline of Implementation of Family Physician Program and Health Insurance in Rural Areas, Version 13. The per capita income considered for each country was gross domestic product based on purchasing-power-parity (PPP) according to International Monetary Fund statistics. Annual income of GPs in the United States ($98,000), Canada ($92,642), Australia ($80,532) and Japan ($71,688) were the highest and in Romania ($4,444), China ($5,675); India ($8,180) and Iran ($12,160) were the lowest. Considering the ratio of annual income of GPs to PPP, physicians in Japan (236%), Canada (224%), India (211%) and the United States (195%) had the highest and physicians in Romania (47%), Czech Republic (69%), China (75%) and Kuwait (96%) had the lowest ratio of income. In this respect, although GPs in India earned one of the lowest annual incomes, they were in one of the top countries according to the ratio of income to PPP. Irrational low incomes for physicians may result in decreased job satisfaction, long working hours, increased risk of medical errors or illegal earnings and consequently decrease in quality of health-care services provided to patients. GPs additional and illegal earnings in the countries with higher income are low and quality of services provided to patients is high. A rational and flexible payment system according to existing conditions can help physicians to achieve their rights in Iran and therefore increase quality of health-care services.