Iranian Journal of Chemistry and Chemical Engineering
Volume:41 Issue: 7, Jul 2022

Most chemical and biological processes are affected by pH. Also, different physiology organs and subcellular partitions could be characterized by their pH levels, as well as their pathophysiological characterization. Sometimes the pH has an extremely critical role in some procedures that the entire research or article focused on pH effect for example the pH was found to play a crucial role, pH has a high effect in different parts of nanotechnology such as shape, size, stability, activity, and morphology of nanostructure materials. Also, several nanochannels and smart doors are developed based on pH changes. In electrochemistry, pH has brilliant roles in oxidation/reduction potential land sensitivity of peak. In the biosensing process, the pH could affect the interaction of the analyte and biorecognition layer by different force and strategies, in some chemical and biochemical reaction and H+ has a catalytic effect, therefore, pH act as a catalyst in several chemical and biological processes. Therefore, finding the best pH for the optimum speed of these processes is critical, especially in biological processes. Electron and proton transfer are rather strongly coupled in many biological processes, also in the separation process for cleaning or measuring process. It is best to check the role of pH in the adsorption and release steps. Usually, it is necessary to find the optimum pH in the first step of the study before optimizing the other parameters.

Protecting the hair, skin, or products of itself are utilized by sunscreen filters which were frequently blocked hazardous UV-Vis radiation. Considering its photoprotective impact on the skin facing the radiation of ultraviolet and visible, TiO2 is a common and cost-efficient photocatalytic structure utilized in sunscreens. In this research, the continual process was done to optimize the green synthesis of TiO2 nanoparticles and nanocomposites through a new, easy, cost-efficient, and quick approach to making nanostructures utilizing a sonochemistry method. SiO2, Al2O3, ZnO, and MnO were utilized to compose green synthesized TiO2 nanoparticles for this purpose. The samples were recognized by XRD, FT-IR, DLS, and SEM. Also, the cytotoxicity and antibacterial activity were assessed. DFT computation was performed to identify the connected energy and band gap energy of nanocomposites by B3LYP/Lan2DZ quantum approach. TiO2/Al2O3 showed a lower size and the lowest agglomeration than synthesized TiO2 and other nanocomposites. Furthermore, all samples indicated strong antibacterial activity against investigated bacteria due to cell death caused by membrane permeability increase and bacterial wall integrity disruption. Nanostructures have cytotoxicity with a low level on A172 cells. The only exception is TiO2/ZnO which indicated a potent index of cytotoxicity on the cancerous cell lines as demonstrated by a low IC50 value of 50 ppm. The relative energy and band gap of nanocomposites indicated that TiO2/Al2O3 has the best stability in chemical and biochemical mediums among other nanocomposites. These green synthesized TiO2/Al2O3 nanostructures may have promising applications in nanoformulation to combat bacterial infections in the future.

Wool proteins have various chemical active groups which could create chemical reactions and bonds with functional groups existent in different substances. Hence, to have special features and competencies, one could perform surface modification of wool fibers using various chemical composites. This paper aims mainly to achieve surface modification of wool fibers by chitosan-nitrogen doped graphene quantum dots (Ch-NGQDs) as bio-based nanocomposites, and to investigate its consequent effects on the various properties of wool fibers such as color fastness, colorimetric parameters, and antibacterial activities. To do this, first, Ch-NGQDs nanocomposites were synthesized including certain weight percentages. Then, wool fibers were modified by prepared nanocomposites. In order to characterize and confirm the synthesis of NGQDs and Ch-NGQDs nanocomposites, FT-IR, XRD, HR-TEM, UV-Visible, and photoluminescence spectrometry were applied. Subsequently, surface modification of wool fibers by Ch-NGQDs nanocomposites was studied using FESEM spectrometry, analysis of fastness properties, colorimetric parameters, and Mueller-Hinton broth antibacterial test. Findings showed that surface modification of wool fibers by Ch-NGQDs nanocomposites led to partial improvement in their color fastness and colorimetric parameters. Additionally, surface modification of wool fibers resulted in the elimination of Staphylococcus aureus bacteria.

This study deals with the interaction between the Amantadine drug (Ad) and the Boron Nitride NanoSheet (BNNSh). The interactions between the Ad molecule and BNNSh, doped Si-BNNSh, Ge-BNNSh, and Ga-BNNSh were carried out at the RCAM-B3LYP method with 6-31G(d) basis set using the Gaussian 09 program. The DFT calculations clarified a weak interaction between the Ad drug and BNNSh. The doped Si, Ge, and Ga-BNNSh were examined to obtain a suitable interaction between the Ad drug and BNNSh to make a suitable sensing device. The adsorption energy (Ead), as well as the gap energy between HOMO and LUMO (Eg), were calculated for the Ad drug and BNNSh and its doped Si-, Ge-, and Ga-BNNSh. The DFT calculations indicated that the Ead of the Ge-BNNSh/Ad complex is -19.67 which was suitable adsorption energy for the sensing ability with low recovery time. Also, the change of % ΔEg for the Ge-BNNSh/Ad is -21.50% which shows a high sensitivity of Ge-BNNSh to the Ad drug. This study showed that Ge-BNNSh is a promising candidate for being a possible sensor of the Ad drug.

In recent times biomolecules engineered magnetically isolable nanoparticles have garnered significant attention in the nanocatalysis arena due to their outstanding features. Doping of rare earth metals over them brings further novelty to their properties. In this current work, we describe the successful synthesis of rare earth lanthanide (M = Pr, Dy) impregnated asparagine-adorned CoFe2O4 as two novel magnetically isolable nanocomposite catalysts following a post-functionalization approach. The synthesized materials were characterized using physicochemical techniques like FT-IR, SEM, EDX, elemental mapping, and ICP-OES analyses. Subsequently, the catalytic efficiency of the materials was investigated in the reduction of 4-Nitrophenol (4-NP), a well-known carcinogenic contaminant of water. The progress of the reaction and its kinetics were monitored over UV-Vis spectroscopy. Among the two variants, Dy anchored catalyst was found to be more efficient than the Pr which led the reaction to completion in just 8 min. Kinetically, also Dy catalyst exhibited higher rate constants. This is the first report of Pr and Dy-anchored heterogeneous catalysts in the reduction of 4-NP. The current methodology is advantageous in terms of cleanliness, simple procedure, excellent yields in short reaction time, easy magnetic retrieval, and reusability of catalysts following several runs without significant change in catalytic activity.

Metal surface coating occupies an important place in the industry. The most important external factor on metal surfaces is corrosion. Corrosion is a natural process that occurs because of a chemical reaction between the metal surfaces and the medium. It causes the degradation of metals. Three methods are used the prevent corrosion. These methods are cathodic protection, anodic protection, and barrier coatings. In this study, it was aimed to develop environmentally friendly corrosion-resistant paint for the barrier coatings, by using zeolite material which has natural characteristics of corrosion resistance. In other words, it was aimed to gain the anticorrosive effect to the production of corrosion-resistant paint by adding modified natural zeolite to the paint. Microscale zeolite was modified by using lanthanum (III) nitrate, zinc acetate, and magnesium chloride solutions. The best results were obtained with a zeolite size of 0.8869 μm and using a 60% zeolite/solution volume ratio. It can be said from the results of the experiments that; thin zeolite film applications are very successful for corrosion resistance paint production. Modified natural zeolite coatings show a very good ability to protect surfaces from corrosion. The results of these procedures are positive and promising. The best result is obtained by zeolite with size reduction and 60% zeolite/solution by volume ratio. The amount of zinc phosphate was greatly reduced. High and low contents of zinc phosphates have almost the same anticorrosive effect with zeolite-modified paint formulations. As a result, cation-exchanged zeolites can be considered a safe and efficient alternative to traditional hazardous pigments in protecting steel surfaces.

In this investigation, a combination of Z1-Z5 hydrazone compounds is obtained from the reaction between 4-methylbenzohydrazide and aryl-aldehydes. A subsequent unique synthetic approach to the preparation of di-substituted tetrazoles T6-T10 was achieved through a 1,3- dipolar cycloaddition of sodium azide and prepared hydrazone compounds in ethyl alcohol. Results have been verified by Fourier-Transform InfraRed (FT-IR)spectroscopy, 1H and 13C-Nuclear Magnetic Resonance (NMR) spectroscopy, and mass spectrometry. The activity of anti-microbial screening has shown that (Z1–Z6 and T10) presented antifungal activity. The other tested Z2 compound was found to exhibit good antibacterial activity, while the other tested compounds revealed low antibacterial activity.

Dibutyltin(IV) complex of 2-[(E)-(4-hydroxy-3-{(E)-[(quinolin-2-yl)imino] methyl} phenyl) diazenyl]benzoic acid was synthesized by refluxing 2-[(E)-(4-hydroxy-3-{(E)-[(quinolin-2-  yl) imino] methyl} phenyl) diazenyl]benzoic acid with dibutyltin(IV) oxide in hot toluene. The complex was characterized by elemental analysis in combination with UV-visible, IR, 1H, 13C, 119Sn NMR spectroscopy, and Mass spectrometry technique. The carboxylate ligand acts as a chelating bidentate mode of coordination with the tin atom in the complex. The complex exhibited a cyclic dimeric structure in the solution state where the tin centers adopt 6- coordinate octahedral geometry. The in vitro antifungal property of the ligand and the complex was observed and compared with the reference drug, Amphotericin-B.

The waste Selective Catalytic Reduction (SCR) catalysts were regenerated by active components supplement on the basis of alkali/acid washing treatment. Through orthogonal design, the regenerated SCR catalyst restored the denitration activity of 98.36% at optimal regeneration parameters of 6% WO3 loaded after 1.2% V2O5 loaded and then calcined at 500 oC. The catalysts were characterized by XRD and H2-TPR techniques. The XRD patterns and the FT-IR spectrogram showed that the supplemented V2O5 and WO3 were dispersed uniformly in an amorphous state on the surface of TiO2 support which remained as the anatase phase. The H2-TPR characterization reported that V2O5 significantly affected the low-temperature activity while WO3 mainly affected the high-temperature activity, the loading sequence of V2O5 before WO3 not only enhanced the interaction between V2O5 and TiO2 but also facilitated the enrichment of WO3 on TiO2 surface.

Methane aromatization reaction to produce benzene using tungsten and molybdenum catalysts supported on ZSM-5 was investigated at 800 ºC. Catalysts were prepared by impregnating tungsten and molybdenum salts on ZSM-5 zeolite with various metal loadings in the range of 2-10 wt. %. To obtain the catalytic structures before and after the reaction, catalysts were characterized by XRD and FT-IR analysis. It was indicated from reactor tests that an increase in metal loading
on the catalyst surface leads to an increase in methane conversion (1.1% and 3.2% for 2W/ZSM-5 and 6 W/ZSM-5, and 2.4% and 4.8% for 2W/ZSM-5 and 6 W/ZSM-5, respectively, at the time of stream, equals 120 min). It was also concluded that Mo catalysts show higher activity and stability than W (methane conversion of 3.2 and 9 % using 10Mo/ ZSM-5 and 10 W/ZSM-5 catalysts respectively, at the time of stream equals 100 min). An increase in Mo loading leads to the enhancement of catalytic activity and methane conversion, indicating that methane's initial activation has occurred on metal sites of catalysts. This activation leads to occur the later reactions and production of final benzene. These conditions confirm the two-factor mechanism which includes two stages: i) hemolysis break of C-H bond and CH3 radical formation and then ethylene formation, and ii) cyclization of ethylene species in the presence of acidic sites within the zeolite channels. Investigations on mesoporous HMS support showed no aromatic production, which shows an increase in support channel diameter leads to reduce the possibility of ring formation.

The extraction of gold in any part of the world is left in the hands of artisanal local miners who do this with the use of mercury which is considered to be a very hazardous chemical to humans and the biophysical environment. This research investigated the use of borax as a replacement for mercury in the extraction of gold from its ore. The sample used for the study was collected from Chanchaga mining site in Niger State. Calcination of the sulphide ore was done at a temperature of 600 oC in order to oxidize the sulphur content of the ore. The Borax in its modified form was used as a metal flux in the extraction process and this was optimized through Box-Behnken experimental design method using Design Expert 7.0 software. The effect of temperature, the mole ratio of heavy mineral concentrate to borax, and time were studied at 800 – 1000 oC, 0.8 – 3.5, and 15-30 min respectively. Sieve, X-Ray Fluorescence (XRF), and carat analysis of the samples were carried out. The percentage yield of gold extract was 70.2 % at 900 oC, 30 min, and 0.8 mole ratio of heavy mineral concentrate to modified borax. The sieve analysis shows that visible gold liberation was achieved between 0.3 and 0.15 mm, and the X-Ray Fluorescence showed 88.7 % extract gold purity with 22 carats. This method can be a replacement for the current toxic method of gold extraction using mercury.

T. callosum an endemic plant, used in this study, efficiently inhibited enzymes, with IC50 values of 28.87 mg/mL, 15.75 mg/mL, 36.47 mg/mL, and 60.0 mg/mL, for AChE, BChE, α-Gly, and GST respectively. The antioxidant activities of the water and methanol extracts of T. callosum were investigated using four in vitro techniques. The antioxidant activity of water extract against ABTS radical was very strong as in the case of standards. Rosmarinic acid (2080.4 µg /g), quercetin-3-D-glycoside (853.8 µg /g), and shikimic acid (784.8 µg /g) were detected as the most intensive phenolic compound in T. Callosum by using the advanced LC-MS/MS technique. The computational screening of the studied ligands revealed the docking energies in the range of -4.217to -9.027kcal/mol for used enzymes. Rosmarinic acid and quercetin 3-O-glucoside showed binding energies of < -8 kcal/mol with AchE and BChE respectively. In conclusion, the biological activities of the plant might be due to its rich chemical composition.

In this study, the optimum conditions for different process parameters were determined for solvent extraction of copper ions from wastewater using reverse micelles. The process parameters viz. copper ion concentration, sodium bis-2-ethyl hexyl sulphosuccinate (AOT) concentration, solution pH, organic to aqueous phase volume ratio, and  NaCl concentration were taken into consideration in response surface methodology, ranging from 30-150 mg/L, 0.04-0.2 [M], 3-11, 0.2-1.0, 0-4 g/100 mL respectively and their effect on percentage removal of copper ions were studied. A regression model was developed by conducting response surface methodology for the analysis of the percentage removal of copper ions from wastewater. As many as fifty-four experiments were procured from the design of experiments for the percentage removal of copper ions. The developed model was employed to optimize the process parameters being considered to maximize the response. The optimum conditions were found to be 30 mg/L copper ion concentration, 0.20 [M] AOT concentration, 3.12 and pH, 0.57 organic to aqueous phase volume ratio, and 0.134 g/100 mL NaCl concentration. The obtained model was validated with experimental data and found to be best fitted within the tolerance limit. The effect of cross-interaction among the process parameters on the percentage removal of copper ions was also investigated. In this study, the copper ion concentration was analyzed by Atomic Absorption Spectroscopy (AAS).

Sargassum Vulgare was used as an effective biosorbent for the removal of Fe3+ from aqueous solutions. Results for batch operation are presented for biosorption onto algal biomass, raw and modified with HNO3, HCl, NaCl, and CaCl2. NaCl was selected as the best modifier for the algae surface for the improvement of the sorption capacity. Optimum biosorption conditions were determined as a function of contact time, biomass dosage, initial metal concentration, and temperature.
The Langmuir isotherm yields high regression values for a maximum monolayer sorption capacity of the modified biomass of 30.52 mg/g at optimum conditions (pH = 2, dose = 5 g/L, t = 120 min, and T= 298 K). This represents an increase of more than 50 % concerning the raw algae. The kinetics of sorption followed the pseudo-first-order rate equations and is fast enough to prove the technique feasible. The thermodynamic parameters showed that the adsorption of Fe3+ using algal biomass was feasible, spontaneous, and exothermic. Modified algae could be regenerated once using 0.001M EDTA solution, and a recovery of 90% of Fe3+ was obtained. Fourier Transform InfraRed (FT-IR) spectroscopy and Scanning Electron Microscopy (SEM) were used to characterize the surface of modified algae.

The applicability of the synthesized NiO-SiO2NPs as a novel adsorbent for eliminating Methylene Blue (MB) dye from aqueous media was investigated. Various techniques including BET, FT-IR, XRD, SEM, and EDS were used to characterize this novel adsorbent. The investigation showed the applicability of NiO-SiO2NPs as an available, suitable, and low-cost adsorbent for the proper removal of MB dye from aqueous media. The effect of pH, adsorbent dosage (dose), initial MB dye concentration (C0) contact time (tc), and temperature (T) on the removal percentage (Ad%) of MB dye onto NiO-SiO2NPs was studied and the optimum value of each factor was determined (pH=7, dose=0.1g, C0=30 mg/L, tc=15 min, and T=298.0 K). The experimental equilibrium data were fitted to the conventional isotherm models and accordingly, Langmuir isotherm has good applicability for the explanation of experimental data with maximum adsorption capacity of the MB dye for SiO2 and NiO-SiO2NPs were roughly 117.0 and 140.0 mg/g respectively. Kinetics experiments were performed to investigate the adsorption kinetics, the pseudo-second-order kinetics coincided quite with the kinetic results. The thermodynamic behavior of the adsorption process was studied by considering the effect of temperature on the adsorption capacity, where the results showed that the process is spontaneous (DG0ad < 0) at the used temperature range and exothermic (DHad0 < 0) with DS0ad < 0. Based on the magnitude of DH0ad < 0, it was concluded that the studied adsorption process is a physisorption one.

The applicability of the synthesized Ricinus Communis-capeed Fe3O4NPs as a novel adsorbent for eliminating Methyl Paraben (MP) from aqueous media was investigated. Various techniques including Brunauer Emmett Teller theory (BET), Fourier Transform InfraRed (FT-IR) spectroscopy, X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Energy Dispersive X-ray (EDX) were used to characterize this novel adsorbent. The maximum adsorption efficiency of (MP) dye onto Ricinus Communis-capeed Fe3O4 NPs was 98.6% at an optimum pH value of 7.0, the adsorbent dosage of 0.01 g, (MP) dye concentration of 15 mg/L, and contact time of 12 min were considered as the ideal values for (MP) dye. The adsorption data fitted well with the Langmuir isotherm model with a correlation coefficient (R2 > 0.97), whereas the adsorption kinetics followed the pseudo-second-order kinetics. The use of an artificial neural network model in predicting data with the Levenberg–Marquardt algorithm, purlin, or a linear transfer function at the output layer, and training was helpful. ANN model as a tool (mean square error) MSEANN = 0.0034, MSEFL = 0.023, and MSEANFIS = 0.0020 for removal of the (MP) dye onto Ricinus Communis-capeed Fe3O4 NPs synthesis. Thermodynamic parameters of free energy (ΔG0), enthalpy (ΔH0), and entropy (ΔS0) of adsorption were determined using isotherms. ∆H0=59.58 kJ/mol, ∆G0= -2.8324 kJ/mol and ∆S0=221.15 kJ/mol. K. The value of (ΔGo, ΔHo, and ΔSo) confirmed the sorption process was endothermic reflecting the affinity of Ricinus Communis-capeed Fe3O4NPs for removing (MP) dye onto Ricinus Communis-capeed Fe3O4NPs process requires heat. The maximum monolayer capacity (qmax) was observed to be 195.0 mg/g for (MP) dye at desired conditions.

The removal of basic dyestuffs (Basic Red 46 and Basic Blue 41) from synthetic dye solutions was examined by using perfluorosulfonic acid-based polymer for the first time in the present study. The effects of four different variables, such as pHs (3.0, 5.0, 7.0, 9.0, and 11.0), temperature (25 °C, 35 °C, 45 °C, 55 °C, and 65 °C), initial dyestuffs concentration (20, 40, 60, 80 and 100 mg L-1) and treatment time (20, 40, 60, 80 and 100 min.) on the removal performance were investigated. The optimum conditions were determined for R46 as pH: 6.5; temperature: 54.1 °C; concentration: 97.4 mg L-1; time: 60.8 min. and for B41 as pH: 7.5; temperature: 54.6 °C; concentration: 67.1 mg L-1; time: 69.5 min. by using Response Surface Methodology. Removal performance values for R46 and B41 were determined respectively 99.9% and 99.5% at the optimum conditions. Also, perfluorosulfonic acid-based polymer was able to regenerate up to 20 cycles without significant performance change for the dyestuff removal process.

Determination of efflux time for draining water, a Newtonian liquid from a large cylindrical open tank through a hole located at the center of the bottom of the tank has been used to study the effect of the addition of water-soluble drag-reducing agents. Two polymers (Polyacryl amide, (PAM) and guar gum), two surfactants (Lauryl sulfate and surf excel), and mixed solutions of guar gum and surf excel were studied.  Four different concentrations of drag-reducing agents were considered for their impact on efflux time. There is a maximum of 1.3% reduction in efflux time (i.e drag reduction) with the addition of aqueous solutions of poly acryl amide while there is 2.8% maximum drag reduction due to guar gum. In the presence of aqueous solutions of Lauryl sulfate surfactant, there is an increase in efflux time i.e (enhancement of drag) while there is a maximum of 2.3% drag reduction when aqueous solutions of Surf excel are used.  With the mixed solutions of Surf excel and Guar gum, a maximum drag reduction of 2.9% has been observed.  This suggests that drag reduction is possible in the tank. and also, at the contraction point at the bottom of the tank. In the concentration ranges considered, polymers either had no effect or reduced drag while the same conclusion cannot be drawn in the case of surfactant solutions.

Noise pollution is one of the challenges of installing equipment and developing industries. The control of noise generated by small power plants is a necessity for its use development. Designing the synthesis of copper and nickel alloy foam and using this foam to reduce noise pollution in the exhaust is an effective method to control and reduce noise pollution in power plants. This study aimed to synthesize copper and nickel alloy foam and compare the effect of results of Sound pressure level) SPL (changes in software ANSYS for three ductless, ideal wall, and multilayer wall modes at different frequencies. In this regard, the adjunct duct is modeled in 3D by the software ANSYS, and the output sound intensity of the duct in the acoustic setting is analyzed in several different modes. The results show that three different modes in the exhaust output indicate that the multilayer wall at most frequencies reduces the sound pressure level relative to ductless or ideal wall modes.

Mahyaveh is a traditional Iranian fish sauce produced by fermentation and hydrolysis. Fish sauce is considered a rich source of protein and contains essential amino acids. The type of fish, salt concentration, and fermentation time are effective on the nitrogen properties of Iranian fish sauce and its quality. Therefore, the aim of this research is to study the type of fish, the salt concentration, and fermentation time on the nitrogen properties and increase the bioactive compounds of Iranian fish sauce (Mahyaveh). The results are shown that the increase in time (30 to 120 days), and salt concentration (35 to 15%) has a significant effect (P≤0.05) on the increase of nitrogen properties, fermentation time (30 to 120 days) and salt concentration (15 to 35%), but decrease on trimethylamine. Multiple optimizations to achieve the maximum nitrogen properties and minimum trimethylamine in the Mahyaveh with 95.56% desirability is obtained at 120 days of fermentation, the salt concentration of 18.73% with the use of sardine. By optimizing the conditions of production, Mahyaveh can be produced with nutritional value and higher quality.

To reduce the importance of fossil fuels, the identification of biofuels plays a vital role. The plant oil chosen for this study is novel plant oil named Jojoba oil (the botanical name is Simmondsia Chinensis).  To utilize this type of oil in higher proportion to diesel, engine modifications were carried out. The engine modifications include optimizing salient operating parameters with Thermal Barrier Coating (TBC). Taguchi and Gray relational methods were used for finding the optimized values of salient operating parameters like injection pressure, compression ratio, injection timing, and intake air temperature as 275 bar, 19.5 CR, 27.5 bTDC, and 65˚C, respectively [1]. This has helped to combust the higher blends of jojoba oil, namely 60J, 70J, and 80J, without adverse performance and emission characteristics. The fundamental aim of coating Aluminium oxide, Molybdenum, and Titanium oxide (40%, 30%, and 30%) on the inner surface of the piston crown and the cylinder head is to retain heat and thereby achieve higher thermal efficiency.  Combustion, performance, and emission analysis were done and found that 60% by volume of jojoba oil can be applied in a TBC engine which offers 11.5% higher BTE, 74.3% lower CO, 31.2% lower HC, 8.6% higher NOx and 25.9% lower smoke than 70% and 80% by volume of jojoba oil.

The thermal performance of a new modified hydronic skirting board heating system with an air supply is investigated in the present work. In the modified system indoor airflow is forced through a duct that is located between the systems. The main aim of the present work is to achieve a system with higher efficiency and lower energy consumption than conventional cases. The heat output rate of the system is evaluated experimentally for different water flow rates and inlet water temperatures based on standard No. En-442. A comparison of the results between the new system and the conventional models shows that heating performance improved by about 23%. Thermal comfort conditions in the room are analyzed according to Fanger’s method and results show that people dissatisfied (PDD) in the different parts of the room is less than 40%. Also to validation of the numerical results, the temperature distribution of the simulation is compared with experimental data and obtained results show that there is a good agreement between them.

The crude oil refinery heat exchanger network (HEN) cleaning schedule is critical to maximize energy recovery and simultaneously maintain HEN performance. In reality, the HEN configuration consists of multiple heat exchanger units with different sizes, fouling rates, and initial efficiencies. The plant availability and the HEN efficiency may decrease to a certain level after a period of operation due to fouling and heat exchangers taken offline for cleaning. Therefore, the cleaning and bypass procedure is deemed necessary. In this study, the heat exchanger performance represented by the overall heat transfer coefficient is evaluated based on a proposed heuristics algorithm for seeking the optimum cleaning schedule while incorporating rigorous cleaning rules. Four heuristic values for HEN cleaning schedule scenarios are proposed to evaluate the overall performance of the HEN. The additional heat duty on the process heater due to cleaning operation and the total annual cost are considered in a crude oil refinery HEN that consists of 11 heat exchanger units. The cleaning frequency of the heat exchanger is found to have a significant effect on HEN performance. The results from the scenario analysis suggest that there is a proper cleaning schedule for the optimum operation of a crude oil refinery HEN. It is also indicated that the design of the cleaning schedule depends on fouling resistance and the capacity of related heat exchangers.

In this work, we study numerically the natural convection of nanofluids (NF) in an inclined flat bottom flask; it is one of the laboratory flasks used in organic chemistry synthesis. The main reason for this study is to enhance the thermal properties of the reaction medium inside the flat bottom flask and to ameliorate the rate of chemical reactions using nanofluids. The flat bottom wall is maintained at a constant high-temperature Th. While the top, left and right walls of the cavity are maintained at a low-temperature TL. The NF comprises Cu and Al2O3 NanoParticles (NP) suspended in pure water. The governing equations are solved numerically using the finite-volume approach and formulated using the Boussinesq approximation. In this simulation we examined the effects of the NP volume fraction (φ) from 0% to 5%, the Rayleigh number from 103 to 106, the various inclination angles of enclosure (γ=0°,5°,10°, 15°) and the NF type (Cu and Al2O3) on the flow streamlines, isotherm distribution, and Nusselt number. The obtained results show that the addition of Cu and Al2O3 NP increases the mean Nusselt number which enhances the heat transfer in the flat bottom flask and causes significant changes in the flow pattern. In addition, the mean Nusselt number is increased with increasing the Rayleigh number and the volume fraction, and the best results have been obtained from the Cu nanofluid. Also, as the inclination angle increases the mean Nusselt number decreases, and the highest value of the Nusselt number was obtained for a vertical enclosure (γ=0°). The obtained streamlines are mostly symmetric and their values are generally increased by increasing the Rayleigh number and volume fractions of NPs. Besides, the obtained isotherms generally follow the geometry of the flat bottom flask.

There are no literature data on the effects of air velocity and relative humidity on moisture diffusivity, mass transfer coefficient, and energy-exergy analysis of chili pepper during cabinet-tray hot-air drying. This study tends to address this gap by presenting comprehensive drying kinetic, energy, and exergy analyses of a cabinet-tray hot-air drying for red chili pepper. Drying was conducted at varying levels of air temperature (40-70 oC), air velocity (0.5-2.0 m/s), and relative humidity (60-75%). The effect of drying conditions on drying time, drying coefficient, lag factor, drying efficiency, moisture ratio, effective moisture diffusivity, mass transfer coefficient, total energy consumption (TEC), specific energy consumption (SEC), energy utilization ratio (EUR), heat loss, energy efficiency, exergy loss, exergy efficiency, exergetic improvement potential (EIP), and exergy sustainability index (ESI)) was evaluated. Five different mass transfer models (Dincer-Dost, Bi-Di, Bi-S, Bi-G, and Bi-Re) were applied to determine the mass transfer parameters. A new drying mathematical model was developed for the prediction of drying kinetic, energy, and exergy parameters. Effective moisture diffusivity values of 1.58×10–8 - 5.10×10–8 m2/s and mass transfer coefficient values of 0.053×10–6 - 8.79×10–6 m/s over the drying conditions range were respectively obtained. The TEC, SEC, and EUR achieved over the range of drying conditions in the course of drying were in the range of 43.56-77.36 MJ, 49.0-87.02 MJ/kg, and 0.035-0.325, respectively. Heat loss and exergy loss varied from 0.16 to 2.39 MJ and from 0.026 to 0.622 kW, respectively. Drying, energy, and exergetic efficiency values obtained varied in the range of 2.80-8.25%, 2.69-7.91%, and 73-94.5%, respectively. EIP and the ESI values varied from 0.0068-0.114 kW and 3.70-18.18, respectively. The developed multivariate linear regression model provided an innovative model to predict drying kinetic, energy, and exergy parameters.

Changing the structure of the microchannel or setting obstacles in the microchannel has become an effective way to improve the mixing performance of a passive micromixer. Here, we design a three-dimensional micromixer with fractal obstacles based on Cantor fractal principle. The effect of fractal obstacle level, micromixer height, spacing between fractal obstacles, and different Re (Reynold number) on the mixing efficiency is studied. Some valuable conclusions are obtained. The micromixer with quadratic fractal obstacles has better mixing efficiency than the micromixer with primary fractal obstacles. With the increase of the micromixer height, the effective folding area of the fluid can be increased. When the spacing between the fractal barriers is 0 µm, the mixing efficiency of the micromixer is better. The mixing efficiency of all micromixers can reach more than 90% at Re is less 0.1 or more than 40. When Re is 70 and 100, the fluid convection in the micromixer is very strong. Finally, the best micromixer CSM600(Cantor structure micromixer with height 600µm) is obtained. The mixing effect is superior to other micromixers under any conditions.

Mahyaveh is the name of a traditional Iranian fish sauce made from the fermentation of small and low-consumption fish, anchovies, and sardines, and contains essential amino acids, vitamins, salts, metal ions, and desirable fatty acids such as Docosahexaenoic acid and Eicosapentaenoic acid. Production conditions and fermentation time can be effective in improving nutritional value and improving its health capabilities. The general purpose of this study was to compare and evaluate the physicochemical, nitrogen, microbial, antioxidant, bioactive, and sensory peptides of Mahyaveh prepared in optimal conditions with traditional Mahyaveh. The results showed that the amount of fat, dry matter, ash, fiber, and carbohydrates of Mahyaveh prepared under optimal conditions was significantly (p≤0.05) higher than traditional Mahyaveh. The amount of moisture and protein in traditional Mahyaveh was significantly (p≤0.05) higher than Mahyaveh prepared in optimal conditions. The amount of total nitrogen, formalin nitrogen, amino nitrogen, proteolysis of essential amino acids, total phenol, and sensory evaluation score in Mahyaveh prepared under optimal conditions was significantly (p≤0.05) higher than the traditional Mahyaveh sample. The amount of trimethylamine, volatile nitrogen, IC50, and microbial load of Mahyaveh prepared under optimal conditions was significantly (p≤0.05) lower than traditional Mahyaveh. The results of this study showed that by optimizing the production conditions of Mahyaveh, fish sauces with higher nutritional value, greater safety, and more desirable sensory properties can be produced than traditional Mahyaveh.

The ‘X’ well is an oil well located in South Sumatra, Indonesia, the well began production (on stream) in June 2017 and is still in production today. Fluid characteristics of heavy oil with a value of 24.6 ºAPI and a high pour point of 48ºC originating from the Talang Akar Formation reservoir. The analysis problem shut-in well after two months of production, and the results of laboratory analysis of oil samples are oils with asphalts problems so that the oil freezes before it reaches the surface. The analysis is carried out in the production well has been done twice with a chemical injection of xylene (C8H10) + toluene (C7H8) and the 'X' well is back in production for 9 days but has decreased oil production by 16% per day until the 'X' well shut-in on 18 January 2018, due to indications of heavy oil deposits in production tubing. Based on data from the EMR (Electric Memory Recorder) starting at a depth of 400 m from the surface the temperature is below the pour point (48ºC) of oil produced. On July 22, 2018, a thermal stimulation project with thermochemical by injecting (HCl 15% + NH3 5% + Ester) was carried out to overcome the asphaltenes problem in the 'X' well.  Thermochemical stimulation succeeded in turning on the 'X' well with Qoi 325 BOPD and raising the wellhead temperature from 30ºC / 86ºF to 50ºC / 122ºF for 100 days and then production lasts  58 BOPD  for 120 days. This research was successful in handling production problems at a mature oil field for 230 days  (almost 8 months) economically and can  operate at low oil price  conditions