Deposition Patterns of Evaporating Sodium Alginate Sessile Droplets Cross-Linked by Calcium Chloride

Controllable patterning of bio-compatible polymers in the presence of a cross-linker in evaporating bi-dispersed colloidal drops is of critical importance in functional coatings, bioprinting, and food packaging. This study investigates the effect of calcium chloride and sodium alginate concentration on the evaporative deposition and elemental distribution of dried-out patterns. Different concentrations of alginate and salt in aqueous solutions are deposited on clean glass substrates to gain a deeper understanding of the final structures. Overall, the results indicate that changing the concentrations of sodium alginate and calcium chloride can significantly alter the elemental distribution and deposition uniformity of the final patterns. The modifications in relative concentration alter the physicochemical characteristics of the solution, resulting in significant changes in the pinning time and contact angle of the droplets that correspond to the alteration of the colloidal size and concentration, ultimately resulting in significant differences in deposition patterns. The dried-out patterns are categorized based on their structures and mechanisms (crystallization, sedimentation, and adsorption) controlling the evaporative deposition, and then justified based on the competitive effects of cross-linking, crystallization, and evaporation-driven flows. Using scanning electron microscopy and energy-dispersive X-ray spectroscopy, the elemental distribution of dried-out patterns is also mapped to substantiate the discussion made.     

Ethyl cellulose/hydroxypropyl methyl cellulose-based oleogel shortening: Effect on batter rheology and physical properties of sponge cake

This study attempts to fill the gap in ongoing research on the design, optimization, and characterization of ethyl cellulose/hydroxypropyl methyl cellulose-based (EC/HPMC-based) low-saturated oleogel-shortenings by examining their functional effects on physicochemical, and rheological properties in the cupcake and its batter. Thus, the commercial shortening was completely replaced with the oleogel-shortenings in the cake formulation and, then, characteristics of the batter (including specific gravity, emulsion stability, and rheological properties), and cake samples (specific volume, moisture content, and texture properties) were evaluated and compared with each other and the control samples (containing commercial-shortening). In short, the EC-based- and EC/HPMC-based-oleogel-shortenings-batters had more specific gravity and emulsion stability than the control-batter. Liner viscoelastic rang in EC/HPMC-based-oleogel-shortenings-batter, EC-based-oleogel-shortenings-batter, and control-batter was 0.212%, 0.159%, and 0.195%, respectively. EC/HPMC-based-oleogel-shortenings-batter had a more viscoelastic behavior than EC-based-oleogel-shortening-batter after the control-batter (p < 0.05). The results of frequency sweep and dynamic shear tests indicated a higher similarity of the rheological behavior of the EC/HPMC-based-oleogel-shortening-batter with the control-batter. The results of moisture content and texture profile analysis of the cake samples indicated a slower staling in the oleogel-shortenings containing samples, especially EC/HPMC-based-oleogel-shortening type.     

On the modeling of the annual corrosion rate in main cables of suspension bridges using combined soft computing model and a novel nature-inspired algorithm

Neural Computing and Applications - Suspension bridges are critical components of transport infrastructure around the world. Therefore, their operating conditions should be effectively monitored to...     

Green Synthesis of Chitosan-Coated Silver Nanoparticle,Characterization, Antimicrobial Activities,and Cytotoxicity Analysis in Cancerous and Normal Cell Lines

Journal of Inorganic and Organometallic Polymers and Materials - The production of silver nanoparticles (AgNPs) using chemical synthesis routes require hazardous and toxic solvents. Nowadays, there...     

1,4-Diazabicyclo [2.2.2] Octane Functionalized Mesoporous Silica SBA-15 (SBA-15@DABCO): a Novel Highly Selective Adsorbent for Selective Separation/Preconcentration of Cr(VI) from Environmental Water Samples

Silicon - In this research, the potential application of 1,4-Diazabicyclo[2.2.2]octane (DABCO) functionalized mesoporous SBA-15 (SBA-15@DABCO) was evaluated as a new and efficient adsorbent for the...     

An accurate model for prediction of gas hydrate formation conditions in mixtures of aqueous electrolyte solutions and alcohol

A new thermodynamic model for calculating the hydrate formation temperature of different hydrate formers in aqueous solutions of both electrolytes and a single alcohol has been presented. This method uses a generalization of the Aasberg‐Petersen model for water activity. For calculation of water activity in the presence of electrolytes, the effect of alcohols was taken into account without using any new fitting parameters. The results are in good agreement with published experimental data. Calculated values of the hydrate formation temperature in the presence of alcohols and electrolytes are compared with those obtained by other existing models. The average absolute error of hydrate formation temperature for 524 available experimental data points is about 0.87 K.     

Ultrasound and water-mediated synthesis of bis-thiazoles catalyzed by Fe(SD)3 as Lewis acid-surfactant-combined catalyst

Preparation of bis-aminothiazoles under different conditions including synthesis in EtOH under ultrasound irradiation and also in water in the presence of Fe(SD)₃ as Lewis acid-surfactant-combined catalyst (LASC) under ultrasound irradiation has been studied. The results were compared with the traditional reflux method. Also, the results confirmed the efficiency of the synthesis in water and under ultrasound irradiation technique. Moreover, the antibacterial activity of products was investigated using the well-diffusion method against bacterial strains including Micrococcus luteus, Escherichia coli, Pseudomonas aeruginosa and Bacillus subtilis. All of the products showed good antibacterial activity against M. luteus and E. coli. Most of the products showed antibacterial activity higher than erythromycin against M. luteus, E. coli, and B. subtilis.     

Preparation and characterisation of hydroxyl-terminated polybutadiene-based polyurethane/graphene nanocomposites

Polyurethane nanocomposites based on hydroxyl-terminated polybutadiene and graphene with different formulations were cured using toluene diisocyanates. The rheological, physical, mechanical, thermal and morphological properties of the nanocomposites were investigated. The viscosity of the samples increased rapidly with graphene content. However, the kinetic rate of the curing process was lower for the nanocomposites in comparison to the neat matrix. The mechanical properties showed a successive increase in the tensile strength and reduction in elongation at break with an increase in graphene content. The highest value of the modulus, density and degradation temperature was obtained for the nanocomposite with 1?wt-% graphene. The hardness properties of the nanocomposites enhanced with curing time. The morphological properties of the nanocomposites are also investigated with the field emission scanning electron microscopy which confirmed the agglomeration occurrence at the high graphene contents.     

Synthesis of a novel sulfonated poly(amide‐imide) and its application in preparation of ultrafiltration PES membranes as a modifier

Sulfonated poly(amide‐imide) (SPAI) copolymer was synthesized, characterized, and blended into poly(ether sulfone) (PES)/dimethylacetamide casting solutions to prepare ultrafiltration membranes. Different weight ratios of the copolymer (0–10 wt %) were mixed in the PES casting solution. The analyses of contact angle and attenuated total reflection‐Fourier transform infrared spectra were used to study hydrophilicity and physicochemical properties of the membrane surface, respectively. The membranes were further characterized by scanning electron microscopy images, ultrafiltration performance, and fouling analyses. The outcomes showed that addition of the SPAI in the PES matrix improved considerably the membranes hydrophilicity. Moreover, with increasing SPAI concentration, the porosity, flux recovery ratio, and pure water permeability of the modified membranes were improved. The pure water flux was increased from 3.6 to 12.4 kg/m² h by increasing 2 wt % SPAI. The antifouling property of the modified PES membranes against bovine serum albumin, tested by a dead‐end filtration setup revealed that bovine serum albumin rejection of the obtained membrane was also enhanced and the antifouling properties of the blending membranes were improved. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46477.     

Flame synthesis of graphene films in open environments

Few-layer graphene is grown on copper and nickel substrates at high rates using a novel flame synthesis method in open-atmosphere environments. Transmittance and resistance properties of the transferred films are similar to those grown by other methods, but the concentration of oxygen, as assessed by X-ray photoelectron spectroscopy, is actually less than that for graphene grown by chemical vapor deposition under near vacuum conditions. The method involves utilizing a multi-element inverse-diffusion-flame burner, where post-flame species and temperatures are radially-uniform upon deposition at a substrate. Advantages of the specific flame synthesis method are scalability for large-area surface coverage, increased growth rates, high purity and yield, continuous processing, and reduced costs due to efficient use of fuel as both heat source and reagent. Additionally, by adjusting local growth conditions, other carbon nanostructures (i.e. nanotubes) are readily synthesized.