Ternary solubility of mono- and di-tert-butyl ethers of glycerol in supercritical carbon dioxide

Using a continuous flow apparatus, the ternary solubility of mono- and di-tert-butyl ethers of glycerol (MTBG and DTBG, respectively) in supercritical carbon dioxide was measured at the temperatures of 313.15, 333.15, and 348.15 K; a pressure range of 80-200 bar; and an expanded gas flow rate of 180 ± 10 mL min⁻¹ at average laboratory temperature of 300.15 K and pressure of 0.89 bar. The ternary solubility of the ethers at the constant temperatures of 333.15 and 348.15 K increased with increasing pressure up to the crossover point (i.e., 152 bar for MTBG and 170 bar for DTBG). MTBG exhibited a higher solubility than DTBG in scCO₂. The experimental data for the ternary solubility of MTBG and DTBG were correlated using the Bartle equation.     

Palm date fibers: analysis and enzymatic hydrolysis

Waste palm dates were subjected to analysis for composition and enzymatic hydrolysis of their flesh fibers. The fruit contained 32% glucose and 30% fructose, while the water-insoluble fibers of its flesh consisted of 49.9% lignin and 20.9% polysaccharides. Water-insoluble fibers were settled to 55% of its initial volume in 12 h. The presence of skin and flesh colloidal fibers results in high viscosity and clogging problems during industrial processes. The settling velocity of the fibers was improved by enzymatic hydrolysis. Hydrolysis resulted in 84.3% conversion of the cellulosic part of the fibers as well as reducing the settling time to 10 minutes and the final settled volume to 4% of the initial volume. It implies easier separation of the fibers and facilitates fermentation processes in the corresponding industries. Two kinds of high- and low-lignin fibers were identified from the water-insoluble fibers. The high-lignin fibers (75% lignin) settled easily, while the low-lignin fibers (41.4% lignin) formed a slurry suspension which settled very slowly. The hydrophilicity of these low-lignin fibers is the major challenge of the industrial processes.     

Sintering Behavior and Machinability of Phlogopite Glass Ceramics Containing Fe2O3

Mica-based glasses in the SiO₂-Al₂O₃-MgO-K₂O-F system were prepared by a sintering method to investigate the effects of different amounts of hematite (Fe₂O₃) on thermal and sintering behaviors besides machinability of the glasses by means of differential thermal analysis (DTA), X-ray diffraction, and scanning electron microscope techniques. DTA analysis on fine and coarse glass powders indicated that the main crystallization mechanism in this system occurred in the bulk rather than the surface. Increasing Fe₂O₃ content to 5 wt.% improved machinability of the glass ceramic. Fe₂O₃ led to the disruption of the glass matrix and facilitated the nucleation of the crystalline phase. Precipitation of sellite (MgF₂) crystals as heterogeneous nucleating sites for potassium phlogopite crystals acted as a second contribution to the machinability of the 5 wt.% Fe₂O₃-containing sample. However, introducing more than 5 wt.% Fe₂O₃ to the base glass prohibited the nucleation of MgF₂, and as a result, large micas formed within the glass. This together with precipitation of cordierite aggregates in highly doped glass with Fe₂O₃ led to lower machinability in these samples.     

Characterization of the produced electrospun fish gelatin nanofiber containing fucoxanthin

Food Science and Biotechnology - This study aims to prepare fish gelatin nanofibers extracted from fish waste by using electrospinning method and its encapsulation with fucoxanthin extracted from...     

Numerical simulation of the wall shear stress distribution in a carotid artery bifurcation

Journal of Mechanical Science and Technology - The effect of stenosis for a carotid artery bifurcation with elastic and rigid walls is investigated numerically. In the present study, the blood flow...     

Energy provisioning in wireless rechargeable sensor networks with limited knowledge

Internet of Things in many applications depends on Wireless Sensor Networks where the sensors are battery powered. Recent advances in wireless energy transfer and rechargeable batteries provide a new chance for Wireless Rechargeable Sensor Networks when the mobile chargers (MCs) patrol the network field and replenish the power of sensors. We consider multiple MCs and a few charging stations (CSs) in the network. The MCs lose their power too, so they move toward CSs to replenish the energy of themselves. We propose an approach named Limited Knowledge Charging (LKC) where each CS makes a virtual area by using grid cells. Based on the cell’s information, CSs coordinate among themselves to direct MCs in the network. The main design goal of LKC is to prolong the network lifetime, by using many techniques such as balancing the energy of network areas. LKC reduces movements of MCs too as a second goal. LKC is an online approach that adapts itself with situation changes of the network. Many related studies use global knowledge, which is not always satisfied in practice. Instead, LKC is a local knowledge approach. Using exhaustive simulation, the satisfaction of the design goals of LKC is demonstrated.

     

A comparative study of Pd/rGO and Pd–Cu/rGO toward electrooxidation of low ethanol concentrations for fuel cell-based breath alcohol analyzer application

Journal of Applied Electrochemistry - The purpose of this work is activity evaluation of optimized Pd–Cu/rGO as an anode catalyst for electrooxidation of low ethanol concentrations...     

Near-field and Far-field Optical Properties of Silver Nanospheres: Theoretical and Experimental Investigations of the Size,Shape, Dielectric Environment,and Composition Effects

Protection of Metals and Physical Chemistry of Surfaces - Collective oscillation of electrons in the conduction band of noble metal nanoparticles is known as localized surface plasmon resonance...     

Physicochemical,rheological, and molecular characterization of colloidal gelatin produced from Common carp by‐products using microwave and ultrasound‐assisted extraction

The effects of ultrasound‐assisted extraction (UAE) and microwave‐assisted extraction (MAE) methods on molecular and physicochemical characteristics of the resultant gelatin were examined. Before extraction procedure, we investigated the optimum pH for swelling of Common carp by‐products, which is an important pretreatment for gelatin production. The highest swelling yield was achieved at pH 13 among pH 1–14 with unit intervals. Results indicated that the UAE gelatin has a higher gel strength, viscosity, melting point, and gelling point. The power and time of sonication showed a reverse relation with these characteristics. In addition, as the time of microwave heating was raised, the gel strength, viscosity, melting point, and gelling point were decreased. The FT‐IR spectra showed similar peaks but the Amide B in UAE gelatin slightly vanished. The electrophoretic pattern also revealed the higher gel strength and viscosity of UAE gelatin due to the higher intensity of α and β chains compared to MAE gelatin. It can be concluded from all of the results of this study that the produced gelatin using these procedures can be a good source of gelatin in food and drug industries.