Iranian journal of chemical engineering
Volume:20 Issue: 4, Autumn 2023

Numerous bone disorders and injuries, such as osteoporosis, are among the most  spreading types of human tissue injuries worldwide, and the available treatments for these injuries are often insufficient and inefficient. Nowadays a lot of attention has been paid to the regenerative medicine, specifically tissue engineering because of its unique features. The extracellular matrix is a key component in tissue engineering because it must have specific properties to support cell survival and proliferation. Natural and synthetic polymeric hydrogels are among the materials commonly employed in tissue engineering. Because the extracellular matrix of bone is particularly mineralized and has a high elasticity, various nanoparticles are commonly utilized to improve the mechanical properties of polymeric hydrogels. In this study, first we extracted the collagen type I from rat tail and characterized it with FTIR spectrum and self-assembly, second we synthesised the bioactive glass nanoparticles and characterized them with XRD and EDAX. Then we developed a polymeric collagen hydrogel (3 mg/ml) scaffold, including bioactive glass nanoparticles (3 %w/v) which increase the mechanical properties of the scaffold (103 pa elastic modulus) in comparison to those of the collagen scaffold (0% w/v nanoparticles), that can be used for bone tissue engineering applications.

A hydrothermal method was used to synthesize different photoanodes for their application in dye-sensitized solar cells (DSSC). These photoanodes included WO3, TiO2, Graphene-TiO2, WO3-TiO2, and a nanostructure of Graphene-WO3-TiO2. The morphology of the nanoparticles was analyzed using the scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), ultraviolet-visible spectroscopy (UV-vis), and Fourier-transform infrared spectroscopy (FTIR). The results demonstrated that the graphene-WO3-TiO2 nanostructure had a large surface area, having provided more active sites for the efficient conversion of solar energy.  Notably, the DSSC incorporating the graphene-WO3-TiO2 nanoparticle electrode outperformed cells based solely on TiO2 and WO3, achieving a higher short-circuit current density of 7.5 mA.cm-2, an open-circuit voltage of 0.68 V, a fill factor of 0.46, and a power conversion efficiency of 2.4%. In contrast, the pure TiO2 and WO3 cells only achieved efficiencies of 0.88% and 0.69% Respectively.  The excellent electron mobility of the ternary nanostructure facilitated the charge trapping and injection into the conductive substrate, reducing recombination. Additionally, the scattering effect of the WO3 nanorods and graphene enhanced the light harvesting in the photoanode, leading to an increase in the overall efficiency of the solar cell. These findings highlight the potential of the synthesized graphene-WO3-TiO2 nanostructure as a promising photoanode material to be applied in DSSC.

The increased demand of the world for energy and its reliance on fossil fuels ultimately contribute to the surge in the levels of carbon dioxide in the atmosphere. To achieve a green, efficient carbon capture, a novel multi-component amine-amino acid solvent including methyldiethanolamine (MDEA), diisopropanolamine (DIPA), and Arginine (ARG) was designated for the CO2 absorption in a T-microreactor. The potential absorption of the aqueous solutions of the desired mixed amines has been assessed through the CO2 absorption percentage (AP) and the total volumetric gas-phase mass transfer coefficient (TGMTC) over a wide range of the gas flow rates (60-240 mL/min), solvent flow rates (2-6 mL/min), under the three mixing concentrations of MDEA: DIPA: ARG (28:8:4), (28:6:6), and (28:4:8)) wt%. The research findings demonstrate an increment of 31% in the absorption percentage of CO2 by reducing DIPA to 4 wt% and raising the concentration of arginine to 8 wt% in the ternary amine solutions. Additionally, the highest mass transfer coefficient of 38.06 (kmol/m3.h.kPa) was achieved utilizing the aqueous solution of MDEA+DIPA+ARG (28+4+8) wt%.

This research presents the performance of bladeless wind turbines. It also familiarizes readers with the phenomenon of eddy current, which serves as the foundation for bladeless turbines. In this direction, these kinds of bladeless turbines have been designed, modeled, and simulated. Firstly, a two-dimensional vibrational movement of the cylinder with a natural frequency of 2 Hz was modeled at Re = 51000. Additionally, it was noted that the values of the displacement amplitude, and lift coefficient are -0.1-0.1, and -1.5-1.5  respectively. After that, using 2D simulation, the impacts of two different geometries, horizontal and vertical ellipsoids, on displacement amplitude are examined. Investigations were conducted on important factors such as lift coefficients and displacement amplitude, as well as the vortex flow pattern formed behind these shapes. It was discovered that the vertical ellipsoid shape had the maximum values for the height of the displacement amplitude, and lift coefficient. The most important factor influencing the performance of this type of geometry was examined, namely the dimensionless Reynolds number, which ranges from 15000 to 90000. It was determined that the intended geometry exhibited a larger displacement response as the Reynolds number increased.

Vacuum swing adsorption (VSA) for CO2 capture has been a focus of significant research efforts aimed at developing innovative CO2 adsorbent materials. In this study, three adsorbents (MAF-66, AC, and CMS) were utilized for capturing CO2 from flue gas through the VSA process, and their performances were compared. The adsorption equilibrium and kinetics data were gathered from recent literature. A four-step VSA cycle was employed to assess the adsorbents' performance for CO2 capture, with a molar feed composition of CO2:N2 at 15:85%. Simulations of two-colums VSA lab-scales with different adsorbents were conducted. The operating conditions such as total feed flowrate, feed composition, feed pressure, temperature, and vacuum pressure were kept constant, and the impact of the adsorbent mass on recovery and productivity was analyzed. The simulation results indicated that both recovery and productivity decreased with increasing adsorbent mass. Furthermore, the necessary amount of each adsorbent to achieve a purity of 99.5% was determined. The modeling outcomes suggested that the VSA process employing MAF-66, CMS, and AC adsorbents would require 1.25, 3.19, and 8.2 grams of the adsorbent, respectively, to achieve N2 purity of 99.5%. Taking into account parameters such as recovery, productivity, and energy consumption, MAF-66 emerged as the most effective adsorbent in this study.