Iranian Journal of Chemistry and Chemical Engineering
Volume:41 Issue: 9, Sep 2022

Despite the huge work concerning the applicability of polymeric hydrogels in the field of drug release, it is still a promising and interesting area for more improvements and trials for preparing newly designed drug delivery systems. In this study, acrylamide and hydroxyl ethyl methacrylate (HEMA) copolymer hydrogels were prepared with the aid of gamma radiation, and the P(AAM/HEMA) nanocomposite hydrogels were obtained by in situ absorption and reduction method of iron salts and silver nitrates (AgNO3) to form P(AAM/HEMA)-Fe3O4 and P(AAM/HEMA)-Ag nanocomposites. The prepared hydrogels and the formed nanoparticles were studied by various techniques; FT-IR, TEM, SEM, and the gel content and swelling behavior were evaluated. FT-IR confirmed the high interaction, which resulted in the successful formation of the AAm/HEMA copolymer hydrogel. TEM provides a good evaluation of the size of the formed Fe3O4 and Ag NPs  to be 12 and 8.5 nm respectively. The prepared hydrogels and nanocomposite hydrogels were examined as drug delivery systems for Ciprofloxacin HCl as a model drug. The results showed that PAM/HEMA-Fe3O4 nanocomposite gave the suitable load and release behavior towards Ciprofloxacin HCl.

Several extensive research studies have explored the advantages of green templates in the synthesis of structure and morphology-controlled photocatalytic nanomaterials. This study compares the potential aspect of Zingiber rhizome Extract (ZE) and Tapioca Starch (TS) extract in modifying the surface and optical properties of Titania NanoParticles (TNP) synthesized by the sol-gel technique. The synthesized nanocatalysts were characterized using various physicochemical techniques. While zingiber extract promotes effectively favored the formation of dual anatase and rutile phases, tapioca extract ended with single anatase phase titania, which was examined for the degradation of Congo red in the presence of sunlight. The photo mineralization and recyclability of catalysts have been evaluated through Total Organic Content analysis. The easy recovery and reusability of biosynthesized nanocatalysts with good control over the grain size, enable them to be an implicit novel green template in the successful synthesis of photoactive mesoporous nano titania.

Age-related Macular Degeneration (AMD) is one of the retinal degenerative diseases associated with some degree of dysfunction and loss of Retinal Pigmented Epithelium (RPE) cells and leads to permanent sight loss. Available treatments only slow down its progression. Applying a scaffold to help RPE cells proliferation and make layers has been proposed as a promising approach to treat this group of diseases. In this study, a fuzzy system was used to optimize the situation of making a scaffold. For better adhesion and proliferation of cells, the polycaprolactone scaffold's surface was modified by alkaline hydrolysis and plasma. Some analyses, such as water uptake and biodegradation rate, were done. Then, differentiated human embryonic stem cells (hESCs) were cultured on several groups of scaffolds. Finally, the viability, proliferation, and morphology of differentiated hESC-RPE cells on all groups of the scaffolds were investigated. The nanofibers' diameter was minimized by optimizing voltage and solution concentration with a fuzzy model for the first time, which obtained 110.5 nm, 18.9 kV, and 0.065 g/mL (w/v), respectively. The immersion time of the scaffold in alkaline solution and solution concentration during surface modification were achieved 4.3 M and 104 minutes, respectively, by response surface methodology. Results of the MTT assay showed that the hydrolyzed group had a high proliferation of cells. Scanning electron microscopy observation of cell morphology after 60 days confirmed this result. In conclusion, our results demonstrate that the hydrolyzed scaffold is a suitable bed for cell proliferation, a good option for AMD treatment.

Clostridium perfringens is an anaerobic bacterium that among its strains, only types B and C can produce beta-toxin. Beta-toxin plays an important role in many human and animal diseases and has detrimental effects on the intestine. The present study aimed to compare two purification methods for the extraction of beta-toxin from C. perfringens type B. As the first method, beta-toxin was purified using ammonium sulfate precipitation, column chromatography (Sephadex G-25), and ion-exchange chromatography (DEAE Sephadex), while the second method employed affinity chromatography. Hemolysis activity and protein content were measured in each step of purification. The purity of beta-toxin was monitored in each step using SDS-PAGE. According to the results, a comparison of these two methods indicated that the yield of the first method was 82.8%, and the yield of the second method was 90.1%. The specific activity values for the first and second methods were calculated to be 2368.1 U/mg and 164.5 U/mg, respectively. Our results show that affinity chromatography could be used to purify beta-toxin from clostridium perfringens type B with high purity and specific activity (4370 HU/mg).

The current study focuses on creating an initial highly alkaline simulated body fluid whose pH can be decreased to a physiological range by adding CO2 (protein-free simulated body fluid) or a combination of CO2 and human proteins (protein-containing simulated body fluid). The effects of dissolved human proteins, Ca2+ ions, and immersed plasma-sprayed hydroxyapatite coatings on the pH and chemical instability of prepared simulated body fluids were investigated. The physiological concentration of dissolved human proteins decreased the pH instability in prepared simulated body fluids by 60% and the physiological concentration of dissolved Ca2+ ions by 15%. The effect of immersing the hydroxyapatite coatings was negligible. In terms of chemical instability, the dissolution of Ca2+ ions caused the blurring of protein-free simulated body fluids after 0.6-1.0 h. In protein-containing simulated body fluids, this phenomenon was undetectable due to their opacity. The effects of human protein presence on the carbonated-apatite-forming ability on the surfaces of immersed hydroxyapatite coatings in the prepared simulated body fluids were also assessed. The experiments validated the bioactivity of plasma-sprayed hydroxyapatite coatings in the prepared simulated body fluids, regardless of protein presence. On the other hand, under the different experimental conditions (unregulated or regulated pH), the human protein presence had an inhibitory (unregulated pH) or indifferent/promoting (regulated pH) influence on the carbonated-apatite-forming ability. The results of the present study are discussed, as well as the strengths and shortcomings of the prepared simulated body fluids, and are compared to those of previous relevant investigations.

Colors are used in foods to make them more appealing. Roselle petals contain functional compounds such as anthocyanins and polyphenols in addition to natural pigments. The objective of this study was to investigate the physicochemical properties of grape and apple juice-based drinks containing anthocyanin extracted from roselle petals. To do this, the extracted pigments were added to the apple juice and the grape juice at concentrations of 5 and 10% w/w. pH, acidity, total phenolic content, anthocyanin, degradation index, hydroxymethylfurfural (HMF), as well as the sensory parameters, were measured for the drink samples stored at 4 and 25 ℃ for 30 days. The results showed that with increasing storage time, pH decreased and acidity increased. The anthocyanin content of the samples ranged from 3.530 to 9.55 mg/ L and their total phenol content ranged from 0.180 to 0.630 mg/mL and the degradation index of the samples ranged from 1.510 to 2.9 80 and their HMF content ranged from 5.560 to 10.260 ppm. With increasing temperature and storage time anthocyanin, total phenolic content decreased and the degradation index, HMF content increased. Apple juice drinks containing 10% anthocyanin stored at 4℃ had the highest polyphenolic and anthocyanin content. The results of the sensory evaluation revealed that the apple juice treatment containing 10% anthocyanin stored at 4℃ was the superior treatment due to its highest bioactive compounds and sensory score.

Multi metal ion sensing unsymmetrical Schiff bases containing ferrocene group attached imine at one side and aromatic moiety connected azomethine on the other side have been synthesized. Titration studies coupled with a UV-Visible spectrophotometer expose the binding aptitude of new receptors. Development of MLCT band near 457 nm for the coordination of Cu2+ ions with new ligands is also noticed. Electrochemical studies of receptor solutions with added metal ions expose quasi-reversible processes by giving superfluous ΔEP values (146-161 mV, then the expected 59 mV). The concentration of metal ions required for effective sensing is calculated from the percentage amount of ΔIpa extracted from the Ipa data. Results obtained in computational molecular docking studies and in-vitro analysis invite more focused research by the pharmacist to develop new formulations for antifungal medicines.

Palm Fatty Acid Distillate (PFAD) is a cheap and valuable by-product of edible oil processing industries. Palm fatty acid distillates are generally used in the soap industry, animal feed industry, and as raw materials for oleochemical industries, in the manufacture of candles, cosmetics, and toiletries. Other applications include their use as food emulsifiers, an aid in rubber processing, in the Flavors and fragrance industries well as in pharmaceutical products. Vitamin E has been extracted commercially from PFAD for encapsulation. This study was carried out to determine the optimization conditions for the esterification of Malaysian PFAD with high-degree polyhydric alcohols (TMP, Di-TMP, PE, and Di-PE) in the presence of sulphuric acid as a catalyst based on four reaction parameters; reaction temperature (°C), reaction time (h), the effect of different alcohols, and molar ratios. The results show that a high conversion of 89% USFA-TMP ester was observed at 150°C, the optimal time for the esterification at 6 h to obtain 91% tri-ester yield, TMP ester produced the highest yield percentage (91%) and the optimum molar ratios were 3.5:1 (USFA: TMP), 4.5:1 (USFA-Di-TMP and USFA: PE) and 6.5:1 (USFA: Di-PE).

In this study, the removal of Mn2+ ions from waters by the adsorption method using ash obtained from a treatment plant sludge burning unit, which is treatment plant waste and mostly disposed of in a landfill, was investigated. By determining the most suitable conditions for adsorption, adsorption kinetics, isotherms, and thermodynamic values were determined. In the experiments, 63.9% removal efficiency was achieved using 10 g/L adsorbent concentration for 10 mg/L Mn+2 under optimum conditions. As a result of the research, it was determined that the adsorption proceeds according to the pseudo-second-degree reaction and abides by the Langmuir isotherm. The thermodynamic constants of ΔH°= -4.866 kJ/mol and ΔS°= 21.44 J/mol were determined. As a result of this, the reaction was exothermic, spontaneous, and random, and adsorption was physical adsorption. As a result of the study, sewage sludge ash can be used in the treatment of water containing low concentrations of Mn2+.

In the presented study, the removal of oxytetracycline (OTC) from aqueous solution by adsorption was investigated onto Active Carbon (AC), Magnetic activated carbon (MagAC), Styrene-Butadiene-Styrene Magnetic Activated Carbon (SBS/MagAC) and poly charbon magnetic activated carbon (PC/MagAC). The process optimization was carried out by investigating the effects of pH, temperature, solid-liquid ratio, adsorbent type, and initial concentrations. The data showed that adsorption reached equilibrium in as little as one hour. less adsorption at low pH values and more at approximately 5.0 values. However, all the materials performed well at room temperature when the situation is examined in terms of kinetics. It was also observed that AC, MagAC, and PC/MagAC are more effective than SBS/MagAC and the initial concentration decreased from 100 ppm to 20 ppm with adsorbents. In addition, at lower concentrations, when 25 ppm and 50 ppm were used, it was observed to 2.5 ppm and 5.0 ppm values. The kinetic results presented that the pseudo-second-order model (r2 ⩾ 0.99) was more effective than that of the pseudo-first-order model (r2 < 0.90). Also, the Intra-particle kinetic model in the adsorption process exhibited two different stages with the diffusion of inter-particle and external diffusion. Adsorption isotherms for all adsorbents were fitted to Langmuir models more effectively than Freundlich models (r2 ⩾ 0.99). Thermodynamics parameters were also calculated. It is seen that OTC can be removed more easily from the aqueous medium by using magnetic and polymeric materials.

SBA (Santa Barbara Amorphous)-15 nano mesoporous molecular sieve was successfully synthesized by hydrothermal method and after its adsorption of Pb2+ the prepared material was used to adsorb S2- from aqueous solution. The surface and pore structure of SBA-15, the (SBA-15)-Pb(II), and the composite material of S2- adsorbed by the (SBA-15)-Pb(II) were characterized by powder X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and low-temperature nitrogen adsorption-desorption isotherm. The effects of solution acidity, S2- concentration, contact time, and temperature on the adsorption of S2- by the (SBA-15)-Pb(II) were investigated. The optimized adsorption conditions were obtained. The adsorption rate for S2- by the (SBA-15)-Pb(II) reached 96.33 %. The change of Gibbs free energy in the adsorption process, DG°<0, can judge that the adsorption process is spontaneous. The enthalpy change in the adsorption process is less than zero, showing that the adsorption process is an exothermic reaction. The negative value of entropy change indicates that the adsorption process is a process of entropy reduction. The adsorption of S2- by the (SBA-15)-Pb(II) belongs to the pseudo-second-order kinetics. Freundlich isothermal adsorption equation can better describe the adsorption process. A novel method has been developed to adsorb S2- from wastewater.

The hydrochloric acid leaching of cadmium, nickel, and cobalt from the dismantled powder of spent rechargeable nickel-cadmium batteries was optimized by the response surface methodology. The optimized parameters included HCl concentration, powder mass, temperature, and solid/solution contact time. The optimal values were 100 mL of 2.6 M HCl, 4.4 g of powder, temperature 48.6 °C, and time 3.19 h. The concentrations of Cd, Ni, and Co in the leach solution were 13500, 12150, and 900 mg/L, respectively. The designed process involved a two-step solvent extraction/back-extraction procedure using 0.5 mol/L trioctylamine (TOA) in dichloromethane as the organic phase. The first step consisted of four successive extraction experiments of the metals from the aqueous phase into the organic phase. The results of this step showed that 92.7% of cadmium and 26.7% of cobalt are extracted into the organic phase. In contrast, nickel ions remain quantitatively in the source phase. The different stability of the anionic chloride complexes of cadmium and cobalt leads to different extractability of these metals. By employing an appropriate back-extraction procedure a selective separation of these ions was achieved. The extracted Cd(II) and Co(II) ion pairs (i.e. [TOAH+][MCl¯3], M is Cd or Co) were back-extracted into the stripping phase by using ammonia solutions as a suitable complexing reagent for these metal ions. Selective back-extraction of cadmium (86.3%) from the organic phase by using 0.5 M NH3 solution has resulted. The second step included five consecutive extraction experiments on the raffinate of the preceding step. The total extraction of cobalt into the accumulated organic phase reached 83.0%. Efficient recovery of the extracted cobalt (79.3%) was obtained by a single back-extraction experiment using 7 M NH3. The investigated design allows for improving Ni/Co ratio from 13.9 in the starting aqueous solution to 106 in the ultimate raffinate.

In this study, a novel Spinning Disc Photo Reactor (SDPR) was designed for the treatment of penicillin v (PV) as objective contaminants under blue Light-Emitting Diodes (LEDs) irradiation. To this end, a visible light-activated Bi2O3/Ag/TiO2 catalyst thin film was deposited onto the surface of ceramic disc support through a facile sol-gel spin coating technique. The synthesized film is fully characterized by X-Ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), Energy-Dispersive Spectrometry (EDS), and Diffuse Reflectance Spectroscopy (DRS)techniques. A Central Composite Design (CCD) was exploited to optimize the operative variables including illumination time, rotational speed, initial PV concentration, and solution flow rate. The PV photodegradation efficiency of 97.67% was achieved at optimal operational conditions involving 80 minutes of illumination time, a rotational speed of 180 rpm, an initial PV concentration of 30 mg/L, and a solution flow rate of 0.8 L/min. Furthermore, the Langmuir-Hinshelwood (L–H) kinetic model fitted the empirical data well. Findings indicated that the developed SDPR can be a prominent alternative technology for the PV degradation process from wastewater.

Urea (NH2CONH2) is very important for the agriculture industry as a nitrogen-rich fertilizer. Urea synthesizes from ammonia (NH3) and carbon dioxide (CO2) at 170 - 180˚C and 143 kg/cm3. This study aims to reduce the amount of urea dust from the flue gas emitted from the Urea Prilling Tower of Khorasan Petrochemical Company. Since the conversion process of molten urea to urea seeds produce much dust, a large amount of environmental pollution caused by this industry can be prevented by examining various factors in dust production in this plant. Thus, the project was divided and implemented into six general phases (Six Sigma project), including problem definition and study phase, measurement and estimation of time and cost required, preliminary analysis, design, and implementation (DMAIC methodology). After implementing the plan, a significant reduction in urea emissions was observed, about 38%. Therefore, the results show that Six Sigma is a useful tool that can accurately predict the removal of urea dust from flue gases.

In this study, two-dimensional simulations are performed to separate polystyrene (PS) and polymethyl methacrylate (PMMA) particles suspended in water using an acoustic field. The acoustic waves are generated by two aluminum interdigitated transducers (IDTs) over a piezoelectric substrate. The effect of input power, inlet flow rate, acoustic frequency, and distance between IDTs and channels on separation efficiency is evaluated by considering channel thickness. It is observed that the separation efficiency is enhanced by increasing acoustic frequency and input power. Also, as the inlet flow rate and distance between IDTs and channel decrease, the separation efficiency increases. The optimum values for input power, flow rate, frequency, and distance are 1.4 W, 0.2 mL/min, 5 MHz, and 75 µm, respectively, and a maximum separation of 88% is achieved.

Biogas, latent energy inside organic components, is a by-product of the anaerobic digestion process. Biogas validity depends on methane composition value. Some organic compounds are not easily accessible to active microorganisms in the anaerobic digestion process due to their nature and structure. These compounds are made available to microorganisms by pretreatment and methane composition is increased. In this study, alkaline pretreatment of solid organic wastes by sodium hydroxide solution was studied through the anaerobic digestion laboratory apparatus. A mixed feed of organic solid waste, previous-stage digested matter, and bovine excrement were considered. Three tests were designed. In the first test, the feed was without pretreatment. Solid organic wastes of the second and third tests were immersed in 0.5 M and 0.1 M sodium hydroxide solution for 24 hours in the laboratory, respectively. The setup was subjected to -0.75 barg vacuum and mesophilic temperature conditions. The mechanical stirrer in digester homogenized substrate medium. The digestion period lasted 40 days. The percentage composition of dry matter, organic matter, humidity, ash, carbon, and nitrogen of the feed and digested were measured. Produced biogas analyzed by gas chromatography. According to the results, produced biogas and methane volume respectively at the 3rd test compare to the 1st test increased 15.52% and 21.31%, and in the 3rd test compare to the 2nd test 19.52% and 2.3 times. Vice versa, produced biogas and methane volumes respectively at the 2nd test compare to the 1st test decreased 3.32% and 63.7%. Sodium hydroxide solution destroys the hard tissue of cellulose lignin and hydrolyzes organic polymers. However, in high concentrations acetogenic and methanogenic microorganisms are inhibited by producing volatile fatty acids and saponification.

The pressure decay of ethylene due to diffusion into the stagnant liquid of N-methyl-2-pyrrolidone (NMP) is evaluated at temperatures of 278.15, 298.15, and 328.15 K, and at three initial pressures of about 0.6, 0.8, and 1.1 MPa. Then, an available graphical method named the initial model is implemented to calculate the diffusion coefficient. Some corrections on the initial model are applied as follows: 1) in the infinite series of the solution to Fick’s second law, more terms are considered. 2) the equilibrium pressure is considered a tuning parameter to eliminate the requirement for an inaccurate experimental measurement. The proposed model is proven to be more reliable and valid for a whole range of pressure decay data including the early times. Due to the large differences between the results of the initial and the proposed models, the Wilke-Chang relation is considered a basis for comparison. This comparative study shows that the results of the Wilke-Chang relation are more compatible with the proposed model.

In this research, the concentrations of several heavy metals such as chromium (Cr), arsenic (As), nickel (Ni), copper (Cu), zinc (Zn), lead (Pb), and cadmium (Cd) were measured using Enrichment Factor (EF), chemical separation, pollution index (Ipoll), ecological Risk Index (RI), and health risk assessments. The results of the soil EF showed that Cr, As, Ni, Zn, and Cu are at a minimum limit of pollution while Pb is at a moderate limit of pollution, and Cd has a significant level of pollution in the soil. The results of the chemical separation of anthropogenic and lithogenous phases demonstrated that the studied elements were of low pollution, except Cd. Based on Ipoll results, all metals were in the non-pollution zone except for Cd. The ER results of the metals in the soil of all metals were low except for Cd. According to USEPA guidelines, the risk of cancer from As, Ni, and Cr metals is high; the risk of Pb is medium; and the risk of Cd is low. The total risk of 9.68E-03 is unacceptable in the risk range because inhalation, ingestion, and skin contact with heavy metals increase cancer risk. During their average life expectancy of 70 years, 3,739 people develop various types of cancer. All metals’ hazard quotient (HQ) is lower than the safe level one in the non-cancer risk assessment. Even so, the total hazard index (HI) of 1.52E + 00 is more than 1, indicating that people are exposed to a variety of non-cancerous diseases due to breathing, swallowing, or skin contact with these metals. Eventually, Monte Carlo simulation uncertainty results in support of the results of cancer and non-cancer risk analysis. Overall, it is concluded that proper management strategies are required to control the concentration of these pollutants in Tehran’s soil to maintain the health of Tehran’s citizens.

Plants are a rich source of phenolic and flavonoid compounds which are among the most important natural antioxidants. The aim of this study was to optimize the extraction of flavonoid, total phenolic, antioxidant, and antimicrobial compounds from Ganoderma (G) Lucidum by the maceration method. To do so, independent variables including temperature, extraction time, and type of solvent along with Box-Behnken Response Surface Methodology (RSM) were used. The results of single optimization of the independent variables showed the highest flavonoid content (15.19 mg/g) with 100% desirability at an extraction time of 48 h, the temperature of 60 °C by using ethanol solvent. The highest total phenolic content (16.96 mg/g) with 99.96% desirability was observed at an extraction time of 26 h, a temperature of 60 °C by using ethanol solvent. The highest amount of antioxidant compounds (3.03 mg/g) or the lowest IC50 value (mg/mL) with 100% desirability was found at an extraction time of 48 h at a temperature of 60 °C by using ethanol solvent. The results of simultaneous optimization of the extraction conditions by maceration method showed the highest flavonoid content (15.20 mg/g), total phenolic content (16.01 mg/g), and the lowest IC50 (3.03 mg/mL) with 98.157% desirability at extraction time of 48 h, the temperature of 60 °C using ethanol solvent. The highest mean Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) of G. lucidum extract obtained by the maceration method were 2500 and 5000 μg/mL, respectively against Clostridium perfringens and Escherichia E. coli. The predicted optimized treatment had superior antimicrobial activity against Staphylococcus aureus with a non-growth halo (Zone of inhibition) diameter of 10.60 mm as compared to C. perfringens and E. coli. The results revealed that the G. lucidum extract obtained by the maceration method could be introduced as an antioxidant and antimicrobial source in marketable food products.

Static Mixers (SM), also generally known as inline mixers, form a newly developing industry trend. They have no moving parts, hence have lower energy consumption, lower installation cost, and very low maintenance cost, and are thus an attractive alternative to conventional agitators. Modifications were made to the design to reduce pressure drop and increase the mixing intensity across the mixer and increase the application of inline mixers in the industries. Three hybrid geometries (different combinations of Kenics and LPD) of static mixers were constructed and simulated using Computational Fluid Dynamics (CFD) tools. Kenics is an excellent radial mixing device, and Low-Pressure Drop (LPD) is an excellent axial mixing device. The key design parameter to modify LPD was the slope angle of elliptical plates which affects the mixer performance. Different slope angles from 90º to 120º were simulated. Kenics was modified for different aspect ratios, and the edge of Kenics was curved. Pressure drop, thermal, and Discrete Phase Model (DPM) analysis were performed on these three different classifications of hybrid geometries. The most promising geometry to emerge based on the low-pressure drop and good mixing efficiency was the curved edge Kenics. Keen-sighted these results, further analysis was performed on curved edge Kenics after the modification of the blend radius. It was concluded that for a lower Reynold number, the curved edge with a higher blend radius dominates all other mixers. Result validation was done by comparing the trends and sensitivity of process variables with the established results and standards.

Experiments were carried out for the numerical investigation of heat transfer enhancement in a solar air collector using different types of baffles and vortex generators. In this study, the vortex generator was implemented to increase the efficiency of the solar air collector. The variations in Nusselt number, pressure drop, friction coefficient, and thermal and exergy efficiency in four collectors with different baffles arrangement (type A, B, C, D) were investigated. Type A was chosen as the optimum collector for implementing the vortex generator on the absorber surface. In the solar air collector the effects of using a novel vortex generator - the Perforated Delta Wing Vortex Generator (PDWVG), in comparison with a flat one - the Flat Delta Wing Vortex Generator (FDWVG), were considered. In order to determine the maximum efficiency of the solar air collector, four different pitch ratios of vortex generators were studied. The Nusselt number and pressure drop increased with the Reynolds number but the friction coefficient decreased with Reynolds; the experimental and numerical results revealed that the thermal and exergy efficiency decreased from a specific range. The comparison of PDWVG and FDWVG showed that the presence of holes on the novel vortex generator led to reduced pressure drop and increased heat transfer between the airflow and the absorber surface. Increasing the number of vortex generator rows had a slight effect on increasing the studied parameters. The results showed that collector type A with ep=0.55 of PDWVG improves the energy and exergy efficiency 4.43% and 5.29% respectively.

Mixing and homogenization of cement paste are some of the most used phenomena in the construction and building industries. In most cases, a homogeneous mixture of cement paste is required and this is supplied by rotary mixers. In the present study, the rotary cement paste mixers in two-dimensional (2D) conditions are investigated by an Incompressible Smoothed Particle Hydrodynamics (ISPH) method. The method is validated and then used to model the cement paste mixer. The cement paste is considered a Bingham fluid. Two types of mixers are examined; shear mixer and blender. An appropriate mixing index that was previously applied to the discrete element method was successfully implemented for the ISPH method, and the performance of these two types of mixers is analyzed with this mixing index. The results show that the Reynolds number has a key role in the mixing in the shear mixers. In the low Reynolds numbers, an unmixed region is formed, which decreases with increasing Reynolds numbers. In blender mixers, the mixing rate is expected to increase with the multiplicity of vortices formed. But the coordinated motion of the vortices with the blades causes a fluid mass to move. Also, the resistance of the fluid to the moving components of the mixer is calculated and the difference in the performance of the two mixers in terms of energy consumption and mixing speed is compared and discussed.

Nanofluids are stable suspensions of nanoparticles in a conventional fluid. They have shown superior potential in heat transfer enhancement. In this research, ZnO/water nanofluids were prepared at various concentrations from 0.2 to 1.5vol%, and their thermal conductivity was measured. The results showed that the thermal conductivity of ZnO/water nanofluids depends on particle concentration and increases non-linearly with the volume fraction of nanoparticles. The effects of particle size and temperature on the thermal conductivity were also investigated at 1.5vol%. The results indicated that thermal conductivity enhanced with decreasing particle size and increasing with temperature. For nanofluids containing 10-15 nm and 45-50 nm particle sizes, the enhancements were 26.3 and 22.8% at 40oC, respectively. In this research, the convective heat transfer coefficient of ZnO/water nanofluids with the above particle sizes was also measured under laminar flow in a horizontal tube heat exchanger. It was observed that both nanofluids showed higher heat transfer coefficients compared to the base fluid at a constant concentration (1.5 vol%). For nanofluids with 10-15 nm and 45-50 nm particle sizes, the average heat transfer coefficient enhancement was 18.1 and 14.9% at Re=1115, respectively.

In this research, Rice Boiling Wastewater (RBW) has been used as inexpensive food wastewater for bio-hydrogen production by dark fermentation. The effective parameters such as temperature, pH, time reaction, and substrate concentration have been optimized.  The 2k-1 factorial design method and response surface methodology were used to optimize the best reaction conditions. According to the results, under optimal conditions pH (6.240), temperature (35.090°C), sugar concentration (5.400 g/l), and fermentation time (36 h), the highest hydrogen production in the proposed theoretical model was obtained equal to 3.30 mol H2/mol glucose. The proposed theoretical model demonstrated a good agreement with the obtained experimental data.

Spiral plate heat exchangers should be efficient devices because they are widely employed in the petrochemical and food industries; furthermore, their operation has a direct impact on electricity consumption in such sectors. For those reasons, this article aims to improve the efficiency of heat exchangers by means of optimization techniques. Using as an objective function the maximization of the overall heat transfer coefficient of a spiral plate heat exchanger. The mathematical formulation includes several variables in the problem: width, length, spacing between the plates, and plate thickness. And as a set of constraints the heat duty and the pressure drop, along with technical considerations associated with this type of system. The General Algebraic Modelling System (GAMS) was purposed as a solution method and compared with the Particle Swarm Optimization (PSO) algorithm, a Genetic Algorithm (GA), the original design proposed by Minton, and the Tuned Wind-Driven Optimizer (TWDO). Results show that the purposed method obtains the highest value of objective function being 1.5% better than the best of the used comparison methods with a computing time of 1e-4s, finding a solution with high quality at a low computational cost.

In this research, a series of experimental and numerical studies on the thermal performance of a single-turn Pulsating Heat Pipe (PHP) using distilled water as base fluid and distilled water including micro-coppers were performed. Thermal resistance, average temperatures of the hot region (evaporator), average temperatures of the cold part (condenser), and two-phase flow regime of the system were investigated at the different filling ratios, at input powers (20, 30, 40, 50 and 60W), at a concentration of micro-coppers (0.0625 g/mL). The oscillating heat pipe was fabricated with a copper capillary tube by choosing the internal and external diameters of 4 mm and 6 mm, respectively. Experiments showed adding micro-coppers into base fluid improves the main mechanism of the PHP based on the oscillating motion of vapor plugs and liquid slugs. The lowest thermal resistance of the system at a filling ratio of 40%, at a concentration of micro-coppers (0.0625 g/ml), at heat input (60 W) was 0.95 deg C/W. Meanwhile, CFD results illustrated adding micro-coppers into base fluid increases the turbulence intensity of the system especially in the evaporator up to 45% which enhances the heat transfer through the PHP in comparison to base fluid.

The synthesis of environmentally friendly biodegradable lubricants has been the focus of the attention of researchers in recent years. As a result of the research, it has been determined that petroleum-based oils can compete with their physical properties. In this study, we examined the synthesis of biolubricant such as trimethylolpropane (TMP) ester from fatty acids methyl esters (FAME) of waste edible oil (WEO) by immobilized lipase Lipozyme TL IM and Novozyme 435. The effects of reaction parameters were investigated. Experimental results, it's indicated that the conversion of FAME to biolubricant was obtained at 83%, and 99% with high diester (86%) and triester (89%) content in the presence of Lipozyme TL IM and Novozyme 435 respectively. As a result of the experimental studies the physical properties of trimethylolpropane triester obtained by Novozyme 435 catalysis showed a high flash point (229 ºC), pour point (-18 ºC), high viscosity index (170) with physical properties that met the requirements between ISO VG32-37 standards. This study showed that lubricant derived from WEO FAME’s has great potential to be used as a base stock regarding favorable biodegradability and physical performance.

Smart wells are unique tools for the management of oil reservoirs under waterflooding to increase the oil flow rate and reduce the associated wastewater production costs. The costs associated with smart completion are considerable. Consequently, the decision for designing and controlling such completion elements can have considerable impacts on project profitability. This work presents an efficient production scheduling for a multi-layer reservoir during water flooding by regulating water movement in the layers to control associated wastewater using intelligent elements. The central focus of this research is to give a production schedule using smart well completions. To achieve this, several segments of the production and injection wells are controlled independently with the schedules provided by a model-based optimization technique. To perform optimization, three methods are used to regulate waterfront and velocity in different layers; the first approach is used to regulate production well according to the saturation distribution in the reservoir without considering NPV. The second approach is the sequential optimization of well controls including flow rates and bottom-hole pressures, to find an optimized NPV. The third approach is to optimize flow rates and bottom-hole pressures for different segments in the production and injection wells, simultaneously, to achieve a maximized NPV using a genetic optimization algorithm. To evaluate these approaches, 2D and 3D reservoir models are used as case studies. The study shows a considerable increase in NPV concerning conventional wells in a fair comparison ground. In the 2D model, 9.89%, 11.75%, and 11.78% additional recoveries are achieved compared to a conventional production well using the first, second, and third optimization approaches, respectively. For the 3D model, 5.87%, 5.99%, and 6.20% were additional recoveries concerning the equivalent conventional production wells, for the first, second, and third approaches, respectively. This additional recovery is due to lower produced associated water and bypassed oil.

Benzene is one of the major constituents of the volatile organic pollutants family and one of the major pollutants in air pollution, which contains the most extensive chemical compound used in both natural processes and synthetic processes. The main way to contact benzene in the industry is through the respiratory tract. Exposure to benzene can cause many of the most dangerous adverse health effects, especially leukemia. The purpose of this study was to use a high-performance liquid chromatography analysis technique to determine the exposure level of benzene dyeing plant workers and the bioassay of trans-trans muconic acid in urine. This is a case-control study. 65 painting factory workers (in two groups exposed to benzene and not exposed to masks and without respiratory masks) participated in this study. Samples were collected at the beginning and end of the shift. High-performance liquid chromatography (HPLC) was used to determine the concentration of trans-trans muconic acid in urine samples. The results showed that the mean concentration of trans-trans muconic acid as a metabolite of benzene in the urine of exposed workers (mean ± standard deviation) was 2.7025± 3.18126 (ppm) and the mean concentration of trans-trans muconic acid in workers with mask (mean ± standard deviation) is 1.4079±2.73664 (ppm). Statistical analysis of the results between the two groups showed that the exposure to benzene concentration between workers with and without respiratory masks was (p=0.246) and was P> 0.05. Consequently, there was no significant difference between the two groups. The present study shows that the average concentration of transmucosal acid in workers' urine indicates exposure to higher concentrations than standard benzene, so it can be said that these people are at risk for occupational diseases, occupational cancers, and other side effects. are. From exposure to these pollutants.