A molecular dynamics simulation of the effect of the toluene catalytic ratios and initial temperature on the catalytic combustion of air/methane inside a microchannel.

METHODS: This research studied the effect of initial temperature (300-400K), and atomic percentage of toluene catalyst (1-10%) on the atomic and thermal performance of air/methane catalytic combustion. The present study was performed using molecular dynamics (MD) simulation. CONTEXT: The results demonstrate that by increasing the initial temperature from 300 to 400 K, the maximum velocity and temperature increased from 0.52 Å/ps and 585 K to 0.72 Å/ ps and 629 K, respectively. Moreover, the heat flux, thermal conductivity, and combustion efficiency increased from 2020 W/m2, 1.45 W/mK, and 93% to 2208 W/m2, 1.55 W/mK, and 97% by increasing initial temperature to 400 K. On the other hand, by increasing the atomic percentage of toluene catalyst from 1% to 4%, the maximum velocity and temperature increased from 0.41Å/ps and 546 K to 0.49 Å/ ps and 573 K, respectively. Thermal conductivity and combustion efficiency increased from 1.451.22 W/mK and 77% to 1.33 W/mK and 89%. With further increasing of the catalyst to 10%, the thermal performance of sample declined. This decrease could be attributed to the agglomeration process, where an excessive amount of catalyst may lead to agglomeration, negatively affecting the structure's catalytic activity and overall thermal performance.

Sonocrystallization of a novel ZIF/zeolite composite adsorbent with high chemical stability for removal of the pharmaceutical pollutant azithromycin from contaminated water.

Water pollution management, reduction, and elimination are critical challenges of the current era that threaten millions of lives. By spreading the coronavirus in December 2019, the use of antibiotics, such as azithromycin increased. This drug was not metabolized, and entered the surface waters. ZIF-8/Zeolit composite was made by the sonochemical method. Furthermore, the effect of pH, the regeneration of adsorbents, kinetics, isotherms, and thermodynamics were attended. The adsorption capacity of zeolite, ZIF-8, and the composite ZIF-8/Zeolite were 22.37, 235.3, and 131 mg/g, respectively. The adsorbent reaches the equilibrium in 60 min, and at pH = 8. The adsorption process was spontaneous, endothermic associated with increased entropy. The results of the experiment were analyzed using Langmuir isotherms and pseudo-second order kinetic models with a R2 of 0.99, and successfully removing the composite by 85% in 10 cycles. It indicated that the maximum amount of drug could be removed with a small amount of composite.

Science and Technology of Additive Manufacturing Progress: Processes, Materials, and Applications.

As a special review article, several significant and applied results in 3D printing and additive manufacturing (AM) science and technology are reviewed and studied. Which, the reviewed research works were published in 2020. Then, we would have another review article for 2021 and 2022. The main purpose is to collect new and applied research results as a useful package for researchers. Nowadays, AM is an extremely discussed topic and subject in scientific and industrial societies, as well as a new vision of the unknown modern world. Also, the future of AM materials is toward fundamental changes. Which, AM would be an ongoing new industrial revolution in the digital world. With parallel methods and similar technologies, considerable developments have been made in 4D in recent years. AM as a tool is related to the 4th industrial revolution. So, AM and 3D printing are moving towards the fifth industrial revolution. In addition, a study on AM is vital for generating the next developments, which are beneficial for human beings and life. Thus, this article presents the brief, updated, and applied methods and results published in 2020.

Investigation of the effects of porosity and volume fraction on the atomic behavior of cancer cells and microvascular cells of 3DN5 and 5OTF macromolecular structures during hematogenous metastasis using the molecular dynamics method.

BACKGROUND AND OBJECTIVE: The molecular dynamics (MD) simulation is a powerful tool for researching how cancer patients are treated. The efficiency of many factors may be predicted using this approach in great detail and with atomic accuracy. METHODS: The MD simulation method was used to investigate the impact of porosity and the number of cancer cells on the atomic behavior of cancer cells during the hematogenous spread. In order to examine the stability of simulated structures, temperature and potential energy (PE) values are used. To evaluate how cell structure has changed, physical parameters such as gyration radius, interaction force, and interaction energy are also used. RESULTS: The findings demonstrate that the samples' gyration radius, interaction energy, and interaction force rose from 41.33 Å, -551.38 kcal/mol, and -207.10 kcal/mol Å to 49.49, -535.94 kcal/mol, and -190.05 kcal/mol Å, respectively, when the porosity grew from 0% to 5%. Also, the interaction energy and force in the samples fell from -551.38 kcal/mol and -207.10 kcal/mol to -588.03 kcal/mol and -237.81 kcal/mol Å, and the amount of gyration radius reduced from 41.33 to 37.14 Å as the number of cancer cells rose from 1 to 5 molecules. The strength and stability of the simulated samples will improve when the radius of gyration is decreased. CONCLUSIONS: Therefore, high accumulation of cancer cells will make them resistant to atomic collapse. It is expected that the results of this simulation should be used to optimize cancer treatment processes further.

Molecular dynamics simulation of thermal characteristics of globulin protein dissolved in dilute salt solutions using equilibrium and non-equilibrium methods.

The aggregation of 7S globulin protein (7SGP) in mature soybean (Glycine max) seeds is an extracellular matrix protein. This atomic compound can be detected in various food products. So, this protein structure's thermal properties (TP) can be important for various food industry products. Molecular Dynamics (MD) simulations describe the atomic arrangement of this protein and forecast TP of them in various initial conditions. The present computational work estimates the 7SGP thermal behavior (TB) by equilibrium (E) and non-equilibrium (NE) methods. In these two methods, the 7SGP is represented using DREIDING interatomic potential. MD outputs predicted 0.59 and 0.58 W/mK values for thermal conductivity (TC) of 7SGP at T0 = 300 K and P0 = 1 bar using E and NE methods. Furthermore, computational results represented that the pressure (P) and temperature (T) are significant factors for the TB of 7SGP. Numerically, TC of 7SGP reaches 0.68 W/mK, 0.52 W/mK by T/P increasing. MD results predicted the interaction energy (IE) between 7SGP and aqueous media could fluctuate between -110.64 and 161.53 kcal/mol by the change in T/P after t = 10 ns?These results should be supposed to design new methods for various food industry purposes, such as producing and processing edible oils.

A novel competitive exact approach to solve assembly line balancing problems based on lexicographic order of vectors.

The assembly line balancing problem (ALBP) is an eminent NP-hard topic that is discussed in mass production systems with low diversity. Primarily, two types of ALBPs are discussed in the literature as type I, which aims to find the minimum number of workstations for a given cycle time, and type II, which assigns some tasks to a given number of workstations such that the maximum workstation load is minimized. To solve ALBPs, various exact, heuristic, and metaheuristic methods have been proposed. However, these methods lose their efficiency when handling large-size problems. Therefore, researchers have focused on proposing heuristic and metaheuristic algorithms to solve large-size problems, especially when they deal with real-life case problems in the industry. This study aims to present a novel and competitive exact method for solving ALBP type II based on the lexicographic order of vectors for feasible solutions. To evaluate the performance of the developed method, a group of highly used standard test problems in the literature is utilized, and the results are compared and discussed in detail. The computational results in this study specify that the developed solution approach performs efficiently and yields the best global solution of all the ALB test problems, which proves the proposed method's potential and its competitive advantage.

Numerical study of location and depth of rectangular grooves on the turbulent heat transfer performance and characteristics of CuO-water nanofluid flow.

This current work expresses numerical simulation of forced turbulent flow convection in a grooved cylinder. Rectangular grooves with a spacing of A = 1, A = 1.1, and A = 1.3, and groove depth to cylinder diameter of e/D = 0.1 and 0.2 were considered. This research concentrates on the effect of groove depth, location of the grooves and CuO nanoparticles on the heat transfer for Reynolds numbers 10000, 12,500, 15,000 and 17,500 in volume fractions of 0, 1, 2, 3 and 4% of nanoparticles. Results show that grooves improve heat transfer. This behavior at a lower A ratio results in a significant Nu number increase so that the highest Nu number occurs for A ratio of 1, 1.1 and 1.3. Increasing e/D ratio, due to increasing the channel section in this area, results in loss of velocity and dissipation of flow momentum, resulting in lower convective heat transfer and lower Nu number. Changing the pitch for e/D = 0.1 results in a 1.1 to 1.6 times increase of Nu number compared with the smooth channel, and for e/D = 0.2 this value is 1.1-1.5 times the smooth channel for similar Re, φ and geometry. Changing groove pitch at e/D = 0.1 results in a 2.1-2.9 times increase in friction factor compared with the smooth channel in similar conditions. For e/D = 0.2, this increase is 1.8-2.8 times the smooth channel. In low Re, the thermal performance is higher than in higher velocities. This is because the grooved channel acts as a smooth channel at high Re, and the average Nu does not have significant growth.

Characterization and synthesis of new adsorbents with some natural waste materials for the purification of aqueous solutions.

In this study, hexavalent chromium Removal from aqueous environments was investigated by using polyaniline composites with some natural waste materials. Batch experiments were used, and some parameters such as contact time, pH and adsorption isotherms were determined for the best composite with the highest removal efficiency. Scanning Electron Microscope (SEM), Fourier Transform Infrared (FTIR) spectroscopy, and X-ray Diffraction (XRD) were used to characterize the composites. According to the results, the polyaniline/walnut shell charcoal/PEG composite outperformed other composites and showed the highest chromium removal efficiency of 79.22%. Polyaniline/walnut shell charcoal/PEG has a larger specific surface area of 9.291 (m2/gr) which leads to an increase in its removal efficiency. For this composite, the highest removal efficiency was obtained at the pH = 2 and 30 min contact time. The maximum calculated adsorption capacity was 500 mg/g.

Removal of chromium (VI) from aqueous environments using composites of polyaniline-cherry leaves.

Composites of Polyaniline (PANI)-prune, peach, cherry, grape, fig and walnut leaves were synthesized under various conditions and were used to remove chromium (VI) from aqueous environments in discontinuous experiments. The results showed that the highest percentage of Cr (VI) removal (40.3%) belonged to the composite consisting of cherry leaves and PANI. Synthesis conditions of this composite were then studied to increase Cr (VI) removal. The results of the experiment on the various solvents are used in the synthesis of the composite of PANI-cherry leaves indicated that the best solvent (with 40.93% Crn(VI) removal) was water. The effects of polyvinyl alcohol (PVA) and polyethylene glycol (PEG) as additives on the synthesis of the composite PANI-cherry leaves were studied and it was revealed that the best-synthesized composite (with 51.64% Cr removal) was produced in presence of PVA (2 g/L), and the optimum pH and contact time were 2 and 30 min, respectively. Moreover, the adsorption process followed Langmuir and Freundlich adsorption isotherms, and the maximum Cr adsorption capacity was 33.01 mg/g. The results of the FTIR and XRD tests and SEM images for this composite were studied. The SEM images demonstrated that the addition of PVA reduced the size of the particles and made them more uniform. The XRD test indicated that the synthesized composite was amorphous, and the FTIR test confirmed the synthesis of the composite.

Using feed-forward perceptron Artificial Neural Network (ANN) model to determine the rolling force, power and slip of the tandem cold rolling.

In this paper, an Artificial Neural Network (ANN) is used to investigate the influence of rolling parameters such as thickness reduction, inter-strand tension, rolling speed and friction on the rolling force, rolling power, and slip of tandem cold rolling. For this reason, the rolling power was derived for 195 various experiments through a series of observation tests. The network is trained and tested using real data collected from a practical tandem rolling line. The best topology of the ANN is determined by Broyden-Fletcher-Goldfarb-Shanno (BFGS) training algorithm and error, and nine neurons in the hidden layer had the best performance. The average of the training, testing, and validating correlation coefficients data sets are mentioned 0.947, 0.924, and 0.943, respectively. The obtained results show MSE value 4.2 × 10-4 for predicting slip. In addition, the effect of friction and angular velocity condition on the cold rolling critical slip phenomena are investigated. The results show that ANNs can accurately predict the cold rolling parameters considered in this study.

Fabrication and finite element simulation of antibacterial 3D printed Poly L-lactic acid scaffolds coated with alginate/magnesium oxide for bone tissue regeneration.

This study proposes 3D-printed Poly L-lactic acid (PLA) scaffolds coated with alginate/MgO, and includes three different cellular topologies. Three unique scaffold models were considered: Perovskite type 1 (P1), Perovskite type 2 (P2), and IWP. Each scaffold was coated with alginate/MgO at the concentrations of 0 wt%, 5 wt%, 10 wt%, 15 wt%, and 20 wt%. For morphological and phase study, the microstructure of fabricated scaffolds was characterized using a Field Emission Scanning Electron Microscope (FESEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD) analysis. Besides, the biological characteristics of scaffolds, such as biocompatibility, antibacterial activity, and cell survival were studied after 21 days of soaking in the simulated body fluid (SBF). The results of biological studies indicate that the apatite layer covered the majority of composite scaffold's surface and sealed the pores' surface. The material properties of Alginate/MgO RVEs were evaluated under PBC, and it described that the elastic modulus enhanced from 100 (pure Alginate) to 130 MPA by adding 20 wt% MgO nanoparticles. The presented findings were compared to the results obtained by the experimental procedure and revealed satisfactory agreement. RVE-achieved material properties were used in the additional studies on the scaffolds to find the best candidate due to the material properties and architectures. Furthermore, experiment and finite element simulation were used to evaluate the mechanical properties of scaffolds under the compressive deformation. According to the results, the compressive strength of structures follows the order σPerovskite type 1>σPerovskite type 2 >σIWP. The results indicate that increasing MgO content from 0 wt% to 20 wt% enhances each structure's compressive strength and elastic modulus. In conclusion, based on the biological findings and simulation results, PLA scaffold with Perovskite type 1 (P1) architecture coated with Alginate/ 20 wt% MgO had the best response which is the final research candidate.

Optimal viscosity modelling of 10W40 oil-based MWCNT (40%)-TiO2 (60%) nanofluid using Response Surface Methodology (RSM).

The science of nanofluids is still fairly new and due to this, the properties of many nanofluids are yet to be explored. Therefore, equations for precise calculations in this field are not available yet. For this reason, as a thermophysical property of an MWCNT (40%)/TiO2 (60%) hybrid nanofluid (HNF), in this research, the viscosity of HNF with 10W40 oil as the base fluid, in a temperature range of T = 5-55 °C and with solid volume fractions of SVF = 0.5-1% is studied and modelled. The viscosity of the nanofluid was examined in different conditions. Lab data were used to model dynamic viscosity of HNF using the Response Surface Methodology (RSM), and first, second, third, fourth and fifth-order models were created. An analysis of the statistical parameters concluded that with a correlation coefficient of 0.9999, the fifth-order model is the best performer. The trend of alterations in viscosity shows that an increase in temperature has great effects on viscosity, and its influence is also more important than that of changes in shear rate (SR) and SVF. Optimal viscosity was also calculated and was equal to 158.1 mPa.sec at SVF = 0.05 %, SR = 11,997 s- 1 and T = 14.97 °C.

Investigating the rheological behavior of a hybrid nanofluid (HNF) to present to the industry.

Hybrid nanofluids (HNFs) are potential fluids that have higher thermophysical properties than conventional nanofluids of heat transfer and viscosity. HNF is a new generation of nanofluid that is produced by dispersing two or more types of dissimilar nanoparticles (NPs) in the base fluid. In this study, the rheological behavior of MWCNT (25%)-MgO (75%)/SAE40 HNF was investigated experimentally, statistically and numerically. Temperature conditions are in the range of T = 50-25 °C, solid volume fractions (SVFs) are in the range of SVF = 0.0625-1% and shear rate (SR) is in the range of SR = 666.5-7998 s-1. This study aims to identify the rheological behavior of HNF based on the effective factors of temperature, SR, and SVF. Various methods show that HNFs exhibit non-Newtonian behavior. The numerical values of the power-law index (n) at T = 50 °C and SVF = 0.75% show the strongest non-Newtonian behavior of HNF and n = 0.9233 is reported. Using laboratory findings, the maximum and minimum viscosities of the base oil increase and decrease by 24% and -8.50%, respectively. Using the response surface methodology (RSM), the relationship between experimental data and modeled data is determined. A quadratic three-variable model with R2 = 0.9994 is used to predict the data.

Numerical investigation the hydrodynamic parameters of the flow in a wavy corrugated channel using different turbulence models.

In this research, turbulent flow numerical models in a wavy channel were investigated. The studied channel is simulated in two dimensions and symmetrically in the range of Reynolds numbers from Re=10,000 to 80,000. The significant cause of this research is to investigate and determine the appropriate method for estimating the behavior of turbulent flow in a wavy channel. In this research, the behavior of turbulent flow in a wavy channel will be simulated in 7 different ways, which are k-ω SST, k-ϵ RN, k-ϵ Realizable, k-ϵ Standard, k-ω Standard, Reynolds stress and Spalart-Allmaras. The findings of this research show that the impacts of the presence of flow viscosity (friction) and the presence of adverse pressure gradients are factors that strongly affect the velocity profiles in the upstream areas of the corrugated section. Among the studied models, due to better compatibility and guessing of flow and hydrodynamic properties, k-ω SST methods and Reynolds and Spalart-Allmaras stress are introduced as the best methods for such geometries. On the other hand, increasing the accuracy of other turbulence methods is related to the flow physics and geometric structure of each problem. In this research, the hydrodynamic parameters of the flow such as pressure drop, skin friction factor, and dynamic pressure drop coefficient and vortex contours, and pressure are plotted and described.

Fabrication of chitosan-gelatin films incorporated with thymol-loaded alginate microparticles for controlled drug delivery, antibacterial activity and wound healing: In-vitro and in-vivo studies.

Previously, studies have demonstrated the unique characteristics of chitosan-gelatin films as wound dressings applications. However, their application has been limited due to their inadequacy of antimicrobial and anti-inflammatory characteristics. To improve the intended multifunctional characteristics of chitosan-gelatin film, in this study, we designed a novel composite film with the capability of controlled and prolonged release of thymol as a natural antioxidant and antimicrobial drug. Here, thymol-loaded ALG MPs (Thymol-ALG MPs) were prepared by electrospraying method and incorporated into the chitosan-gelatin film. The composite wound dressings of Thymol-ALG MPs incorporated in chitosan-gelatin film (CS-GEL/Thymol-ALG MPs) were characterized by in vitro and in vivo evaluations. The Thymol-ALG MPs demonstrated spherical and uniform morphology, with high encapsulation efficiency (88.9 ± 1.1 %). The CS-GEL/Thymol-ALG MPs exhibited high antibacterial activity against both Gram-positive and Gram-negative bacteria and no cytotoxicity for the L929 fibroblast cells. The release trend of thymol from CS-GEL/Thymol-ALG MPs and Thymol-ALG MPs followed a pseudo-Fickian diffusion mechanism. This wound dressing effectively accelerates the wound healing process at rats' full-thickness skin excisions. Also, the histological analysis demonstrated that the CS-GEL/Thymol-ALG MPs could significantly enhance epithelialization, collagen deposition, and induce skin regeneration. The present antibacterial composite film has promising characteristics for wound dressings applications.

Statistical modeling and investigation of thermal characteristics of a new nanofluid containing cerium oxide powder.

In this paper, the thermal conductivity (knf) of cerium oxide/ethylene glycol nanofluid is extracted for different temperatures (T = 25, 30, 35, 40, 45, and 50 °C) and the volume fraction of nanoparticles ( φ = 0, 0.25, 0.5, 0.75, 1, 1.5, 2 and 2.5%) and then knf is predicted by two methods including Artificial Neural Network (ANN) and fitting method. For both methods, the results have been presented and compared. The experiments showed that with increasing φ and temperature, the thermal conductivity ratio (TCR) of nanofluid increases. It was also observed that when the experiments are performed at high temperatures, the rate of increase in knf is much higher than the change in the same amount of φ change at low temperatures. An ANN with 7 neurons has a correlation coefficient very close to 1 and this proves that the outputs are compatible with experimental results. Also, it can be seen that the ANN could predict the thermal behavior of cerium oxide/ethylene glycol nanofluid more accurately.

Molecular dynamics investigation of the thermal behaviors of magnesium oxide ceramics at different pressures and temperatures.

Today, magnesia ceramics have attracted considerable attention due to their essential properties. Therefore, this paper investigates the impact of temperature (T) and pressure (P) on the thermal manner of magnesia ceramics using molecular dynamics simulations (MDS). As the T increases, the mobility of the structures increases. Therefore, the heat flux (HF) in the structures increments slightly due to the greater movement and the larger oscillation amplitude of the atomic samples. On the other hand, with increasing P, the oscillation amplitude and displacement of atomic samples are limited. Therefore, the thermal properties of the structure are expected to decrease. Studies show that increasing T from 250 to 350 K increases the average HF from 0.73 to 0.89 W/m2. Also, the average thermal conductivity (TC) increases from 30.58 to 38.27 W/mK. So, increasing the T means a certain amount of energy is fluxed in a shorter time. On the other hand, increasing the P from 0 to 5 bar decreases the average HF from 0.82 to 0.65 W/m2. Also, this issue leads to a decrease in the average TC from 33.49 to 30.96 W/mK.

Fabrication of HKUST-1/ZnO/SA nanocomposite for Doxycycline and Naproxen adsorption from contaminated water.

Doxycycline and Naproxen are among the most widely used drugs in the therapy of CoVID 19 disease found in surface water. Water scarcity in recent years has led to research to treat polluted water. One of the easy and low-cost methods for treatment is adsorption. The utilize of Metal-Organic Frameworks (MOFs) to evacuate pharmaceutical contaminants from water sources has been considered by researchers in the last decade. In this research, HKUST-1/ZnO/SA composite with high adsorption capacity, chemical and water stability, recovery, and reuse properties has been synthesized and investigated. By adding 10 wt% of ZnO and 50 wt% of sodium alginate to HKUST-1, at 25 °C and pH = 7, the specific surface area is reduced by 60%. The parameters of drugs concentration C0 =(5,80) mg/L, time=(15,240) min, and pH= (2,12) were investigated, and the results showed that the HKUST-1/ZnO/SA is stable in water for 14 days and it can be used in 10 cycles with 80% removal efficiency. The maximum Adsorption loading of doxycycline and Naproxen upon HKUST-1/ZnO/SA is 97.58 and 80.04 mg/g, respectively. Based on the correlation coefficient (R2), the pseudo-second-order and the Langmuir isotherm models were selected for drug adsorption. The proposed mechanism of drug uptake is by MOFs, hydrogen bonding, electrostatic bonding, and acid-base interaction.

Effect of Duration of Root Canal Infection on the Ability of Dentin-Pulp Complex Regeneration of Immature Permanent Teeth: An Animal Study.

INTRODUCTION: Persistent infection is always considered the most important reason for the failure of dentin-pulp complex regeneration. The present study aimed to evaluate the effect of the duration of root canal infection (from 1-12 weeks) on the ability of dentin-pulp complex regeneration. METHODS: In this animal study, 64 roots of immature premolar teeth of 4 dogs were randomly divided into the following groups: the positive control group, 8 root canals treated with the regenerative endodontic procedure (REP); the negative control group, 12 infected root canals; the intervention groups, 36 root canals infected with supragingival plaque (1, 3, 6, and 12 weeks) and treated with REP; and an additional positive control group, 8 normal roots. After 3 months, the teeth were investigated by radiographic images and immunohistochemical staining (CD31, CD34, and S100 markers). In addition, DSPP gene expression was assessed using a real-time polymerase chain reaction technique. RESULTS: Based on radiologic evaluation among the intervention groups, the highest root canal development (length and width) occurred in the intervention group of 1 week, and the lowest radiologic results were in the intervention groups of 6 and 12 weeks (1-way analysis of variance, P-value < .05). There was a significant difference between the groups in terms of CD31, CD34, S100, and DSPP expression percentage (1-way analysis of variance, P-value < .05); the highest and lowest expression percentages belonged to the 1- and 12-week groups, respectively, among the intervention groups. CONCLUSIONS: This study demonstrated that long root canal infection decreased the ability of the body to regenerate the dentin-pulp complex.