Cellulose nanocrystal addition in thin film nanocomposite membranes: Which monomer solution is preferred?

Cellulose nanocrystals (CNCs) are biodegradable nanoparticles with a high aspect ratio and abundant surface hydroxyl groups resulting in negatively charged hydrophilic surfaces that make them an ideal candidate to be incorporated in thin-film nanocomposite (TFN) membranes. In this study, we modified the CNCs via acetylation (ACNCs) to reduce their hydrophilicity and via reaction with L-cysteine (CysCNCs) to impart them with functionality that promoted their interaction with the trimesoyl chloride organic monomer used in the preparation of the poly(amide) layer of the TFN membranes. These modifications allowed us to question in which monomer solution the nanoparticles should be dispersed. Addition of the unmodified CNCs in either the aqueous or organic monomer solution showed little difference in membrane performance. However, the addition of either the ACNCs or the CysCNCs to the organic monomer solution led to a significant increase in membrane performance in reverse osmosis (RO) and nanofiltration (NF) systems compared to their addition to the aqueous monomer solution. In addition, the CysCNCs exhibited performance very near the upper-bound line for RO and NF.     

Simulation and multi-objective optimization of liquid hydrocarbons production by coupling Blast Furnace Gas with Coke Oven Gas of steelwork

Clean Technologies and Environmental Policy - Steelwork is one of the main CO2 emitters due to three main off-gases of blast furnace gas, coke oven gas, and basic oxygen furnace...     

Preparation of Core/Shell CaO@SiO2-SO3H as a Novel and Recyclable Nanocatalyst for One-Pot Synthesize of Dihydropyrano[2,3-c]Pyrazoles and Tetrahydrobenzo[b]Pyrans

Silicon - The core/shell CaO@SiO2-SO3H nanoparticles were prepared by stabilizing of sulfonic acid on the surface of silica-coated CaO nanoparticles. The structure of CaO@SiO2-SO3H was...     

Optimization of in vitro and in vivo antifungal effects of trehalose coating included Artemisia sieberi essential oil on mulberry (Morus alba var. nigra) fruits using the hybrid RSM-GRA method

Food Science and Biotechnology - Mulberry is prone to microbial contamination due to mechanical damage during the harvesting. This study aimed to determine, and optimize fruit microbial loads, and...     

A Model of Mechanotransduction in Polyvinyl Alcohol-Based Composite Hydrogels for Regulating Musculoskeletal Differentiation

In regenerative medicine, extracellular matrix (ECM)-inspired materials are currently being explored to imitate mechanotransduction pathways and control cell fate. In musculoskeletal tissue regeneration, enhancing mechano-biological signals require biomaterials that are both biocompatible and viscoelastic and can retain water content. Herein, based on these requirements, various polyvinyl alcohol (PVA)-based composite hydrogels, reinforced by polyhydroxy butyrate (PHB) nanofibers, are proposed to differentiate equine adipose-derived stem cells for musculoskeletal regeneration. To study the role of fiber embedding in improving scaffold properties, different nanofiber assemblies, including chopped short ones with random orientation (PVA_S), single-layer (PVA_L1), and double-layer membranes (PVA_L2) are positioned into the PVA matrix. PHB reinforcements negatively affect swelling and positively enhanced phase transition temperatures and crystallinity of PVA hydrogel. According to mechanical analysis results, compositing with PHB nanofibrous layers strengthen the PVA matrix due to some restrictions on PVA chain mobility. Gene expression investigations also reveal that higher matrix stiffness after layering with two PHB membranes (PVA_L2) promotes osteogenesis, while the random addition of short-chapped fibers (PVA_S) facilitate tenogenic differentiation. As a consequence of the findings, fiber placement is crucial to the mechanical properties of composite hydrogels that ultimately control musculoskeletal differentiation signals through mechanosensing pathways.     

Exact analytical solution of forced convection through a porous-saturated duct

In the current paper, the effect of a magnetic field on the fully developed forced convective flow and heat transfer is studied. An exact solution is extracted when the flow in the porous medium is governed by the Brinkman–Forchheimer Extended Darcy model. First, the problem formulation is explained to obtain a new system of mathematical formulation. Then, by utilizing the properties which are imposed into the problem, the exact closed-form analytical solution of the problem is explored. Finally, the main results are illustrated to show the impact of the porous media-shaped parameter, magnetic parameter, Forchheimer number, and viscosity ratio. It should be mentioned that the asymptotic results achieved in this study were compared with the exact results and it is found that they are in good agreement.     

Sintering behavior of Cr2AlC MAX phase synthesized by Spark plasma sintering

In the current study, the sintering and mechanical properties of the Cr₂AlC MAX phase synthesized by Spark plasma sintering at 1000, 1100, and 1200°C were investigated. The X-ray diffraction (XRD) patterns showed that the synthesis of the Cr₂AlC MAX phase was associated with the presence of impurities such as Cr₇C₃ and Al₂O₃. On the basis of the FESEM images equipped with energy dispersive spectrometer, the MAX phases had been formed successfully and the length of these layers increased by enhancing the sintering temperature. The results of the density showed that by increasing the temperature, the density increases from 5.10 to 5.33 g/cm³ and finally decreases to 5.25 g/cm³. Vickers hardness method applied to determine the hardness of the samples showed that the hardness decreases from 8.52 to 8.07 GPa for the prepared samples.     

Effect of Intercritical Annealing Time on the Microstructure and Mechanical Properties of Dual-Phase Steel Processed by Large-Strain Asymmetric Cold-Rolling

Herein, the effect of intercritical annealing time on the microstructure and mechanical properties of dual-phase steel processed by large-strain asymmetric cold-rolling is studied. It is observed that the martensite islands are uniformly distributed in the ferrite phase in the microstructures of dual-phase steels due to performing the asymmetric cold-rolling before intercritical annealing treatment. As the intercritical annealing time increases up to 10 min, the fraction of martensite increases. By increasing the holding time and fraction of martensite, the carbon content of the martensite phase is decreased. The short-term intercritical annealing eliminates the yield point phenomenon. However, intercritical annealing at 860 °C for 20 min leads to the reoccurrence of a yield point phenomenon. Increasing the intercritical annealing time to 10 min improves the yield strength to 505 MPa and ultimate tensile strength to 834 MPa. However, the strength decreases sharply after the holding time of 20 min. There is a perfect linear relationship between the mechanical properties and the fraction of martensite. Ductile failure is observed at the center of the fracture surfaces of dual-phase steels while shear failure occurs at the edges of the fracture surfaces.     

Propagation of Terahertz Pulses in Photonic Crystal-Based Rib Silicon Waveguides

Silicon - Propagation of terahertz (THz) waves in silicon waveguides is of special interest for THz applications such as optical integrated circuits. In this paper, a photonic crystal-based rib...     

Solution combustion synthesis of FeCr2O4:Zn,Al pigment powders

FeCr₂O₄:Zn,Al pigment powders were prepared via a solution combustion synthesis method. Effects of Zn and Al dopants and less/extra Fe content on the structure, molecular bonds, and optical properties of powders were studied. Results showed that addition of dopants as well as extra/less content of Fe led to weaker combustion and consequently lower X-ray diffraction peak intensities, lattice parameters, and differential thermal analysis peak intensities. Moreover, Fourier transform infrared analysis illustrated that the band position of Cr–O and Fe–O bonds were shifted to higher frequencies with moving away from stoichiometry. In addition, scanning electron micrographs showed that in all samples, porous spongy microstructures were formed with highly flake-like agglomerated particles. Furthermore, there was a significant difference between the powder samples and the tiles colored with in glaze powders due to the partial dissolution of pigments in contact with the molten glaze of tiles. In comparison to the tile colored with the stoichiometric FeCr₂O₄ pigments without dopants, the color difference (ΔE) in the tiles colored by the iron chromite pigments doped with Zn and Al dopants and less/extra Fe content reached the high values as large as ΔE = 36.19. The solar reflectance values (R_s) in near-infrared region were above 50% in all samples. Near 80% R_s in the tile colored by the iron chromite pigment doped with 3 mol% Zn and the yellowish brown appearance (L* = 43.44, a* = 6.77, b* = 18.38, c* = 19.59, h = 69.79) showed that the sample was a good candidate for cool building materials such as roof tiles.