Phenolic compounds profile and antioxidant activity of Dorystoechas hastata L. Boiss et Heldr

Phenolic compound profile and antioxidant activity of methanol, acetone, ethyl acetate, water and petroleum ether (b.p. 40–60 °C) extracts of Dorystoechas hastata, endemic to Turkey and being consumed as herbal tea by local inhabitants, have been investigated. HPLC–DAD analysis indicated the presence of chlorogenic, caffeic, p-coumaric, ferulic and rosmarinic acids as phenolic acids, quercetin, kaempferol and apigenin as flavonoids and carnosic acid and carnosol as diterpenoid antioxidants in the plant. Petroleum ether, methanol and water extracts of D. hastata were found to be very effective antioxidative extracts. Petroleum ether extract, having the highest amount of carnosic acid and carnosol contents (531.3 and 389.9 mg/g DW, respectively) among all solvent extracts, was found to have the highest antioxidative potential based on the individual antioxidant activity assays; DPPH, ABTS⁺, TBARS and total phenolic content, expressed as IC₅₀, TEAC, EC₅₀ and TPC values, respectively, and also on the principal component analysis. It exhibited significantly high TEAC (7.1 mM trolox) and low EC₅₀ (54.5 μg/mL) values, indicating the strong potential in in vitro radical scavenging and in inhibiting lipid oxidation. Water extract, with its extremely low IC₅₀ value of 4.9 μg/mL in DPPH radical scavenging and significant TEAC (4.8 mM trolox), EC₅₀ (64.4 μg/mL) and TPC (116.7 mg GAE/g DW) values, was found to be the second highest in antioxidative potential among all extracts. TPC value of methanol extract (147.3 mg GAE/g DW) was found to be significantly higher than the other extracts studied. The results showed that D. hastata can be used as a potential antioxidative edible source due to its different classes of phenolic compounds and strong antioxidative capacity.     

Elastic properties of large‐open‐mesh 2D braided composites: Model predictions and initial experimental findings

Conventional applications of two‐dimensional tubular braided composites mostly require closed‐mesh braiding; however, some stiffness‐critical applications may require use of open‐mesh braiding. Most likely candidates for the open‐mesh braided composites are in the medical field, such as braided catheters and stents. Analytical and experimental investigation of the open‐mesh braided tubular composites is very limited in the open literature; therefore, this study is an initial attempt to close this gap. The article investigates elastic properties of the open‐mesh braided composites (e.g., braided catheters) and open‐mesh composites with holes (i.e., stent‐like structures). Analytical results are also compared with that of experimental results. Findings may be used in design of braided medical tubular composites. POLYM. COMPOS., 31:2017–2024, 2010. © 2010 Society of Plastics Engineers     

Morphologies of electrospun fibers of lignin in poly(ethylene oxide)/N,N‐dimethylformamide

The effects of polyethylene oxide (PEO) molecular weight (Mv), and volume fraction ( ) on the morphology of electrospun sulfur free softwood lignin nanofibers were investigated. Small amounts of PEO were used during preparations of the solutions to aid the electrospinning process. It was found that tripling the PEO volume fraction resulted in a transition from semi‐dilute un‐entangled to semi‐dilute entangled solutions. Conversely, the solution remained in the semi‐dilute un‐entangled regime as the molecular weight was increased by five times. The effects of molecular weight and volume fraction of PEO both on entanglement density and fiber morphology were unified by scaling PEO viscosities as a function of . We investigated and discussed conditions that would produce smooth fibers and conditions that would produce fibers with beads. In the case of beads‐on‐a‐string formation, bead widths remained constant regardless of the molecular weight and concentration of PEO, but the bead length changed. Additionally, we observed a decrease in the diameter of the fibers and the dimension of beads (length and width of beads) with an increase in the electric field used for electrospinning. The aspect ratio of beads increased with increases to both the electric field and the PEO molecular weight or concentration. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44172.     

Experiments and Simulations on Bidisperse Solids Suspension in a Mixing Tank

Experiments and simulations of a solids suspension process in a lab‐scale stirred tank under turbulent conditions have been performed. Two impellers have been tested. The liquid‐solid suspension consists of water and a mixture of glass and bronze particles. The simulations are Eulerian‐Lagrangian with the liquid flow as the Eulerian part, being solved by means of a lattice‐Boltzmann method combined with a large‐eddy approach to turbulence modeling. Comparison with experimental visualizations indicates that the simulations are able to represent the start‐up of the suspension process from a zero‐velocity initial condition. Differences between experiment and simulation are observed near the bottom of the tank. The simulation data are used to highlight the collisional interaction between the two different types of solids, the role of baffles, and the effect of impeller type on the suspension process.     

Determination of chloride and nitrate in butter,margarine, cheese and meat products using ion selective electrodes

Chloride analysis was quite easy and salt contents of all butter and margarine samples were found to be less than 2 g NaCl/kg while those of cheese and meat products were above 10 g/kg. Nitrate analysis was not as easy as chloride analysis due to interferences of chloride and organic ions. These interferences were tried to be eliminated using either Al₂(SO₄)₃ and Ag₂SO₄ solutions or aluminium and silver resins. Results showed that the elimination of interferences is most effective with the use of resins in amounts of 3 g under the present experimental conditions. Nitrate contents of meat products analysed were found to be less than 20 ppm.     

The effect of the monomer feed ratio and applied potential on copolymerization: investigation of the copolymer formation of ferrocene-functionalized metallopolymer and EDOT

In this study, we reported synthesis of ferrocene functioned conducting metallopolymer to enhance the understanding of properties of polymers. One of the crucial ways in the electrochromic polymer materials research was tuning color by means of copolymerization and change of polymer backbones and side groups. For this purpose, we synthesized copolymer of 4-(2,5-di(thiophen-2-yl)-1H-pyrrol-1-yl)amido ferrocenyl dithiophosphonate with EDOT via potentiodynamic electrolysis. Spectral and electrochemical characterizations of the copolymer were investigated. In addition, the spectral properties of the copolymers prepared by different applied potentials and different monomer feed ratio were studied. For the first time, copolymer composition and the monomer reactivity ratios were approximately calculated by using the spectral data.     

In-situ plasma spraying: Alumina formation and in-flight particle diagnostic

In-situ plasma spraying (IPS) is a promising process to fabricate composite coatings with in-situ formed thermodynamically stable phases. In the present study, mechanically alloyed Al-12Si and SiO₂ powder was deposited onto an aluminum substrate by atmospheric plasma spraying (APS) to obtain a composite coating consisting of in-situ formed alumina reinforced hypereutectic Al-18Si matrix alloy. The effects of spray parameters (arc current and spray distance) and in-flight particle characteristics (temperature and velocity) on in-situ reaction intensity (alumina and silicon) have been investigated. The results show that, in-situ alumina formation and silicon intensity strongly depend on in-flight particle characteristics, spray distance and substrate temperature.     

Structural evolution of mechanically alloyed Al-12Si/TiB2/h-BN composite powder coating by atmospheric plasma spraying

In the present study, mechanically alloyed Al-12Si/TiB₂/h-BN composite powder was deposited onto an aluminum substrate by atmospheric plasma spraying. The effect of mechanical alloying (MA) and plasma spray parameters on composite powder and coating structure were investigated. It has been observed that the MA process has a significant effect on the composite powder morphology and reactivity between the selective powders. Results also demonstrate that, at relatively high milling time h-BN decomposes into B and N and forms a solid solution. Also, it has been found that, the relative amount of the in-situ formed AlN through the reaction between h-BN and Al and/or the decomposition of Al-B-N solid solution is independent from the plasma parameters (arc current and secondary gas flow rate). However, spray parameters remarkably affects the coating hardness due to coarsening of Si during the solidification of the coating.     

Kinetic analysis of the loss of some B-vitamins during the cooking of macaroni

The kinetics of the losses of thiamin, niacinamide, and riboflavin were investigated during the cooking of macaroni at 50, 75, 80, 85, and 90 °C. Simultaneous analysis of the vitamins was achieved by HPLC using a μ-Bondapak column. The activation energies for the losses of thiamin, niacinamide, and riboflavin were determined as 25 kJ/mol, 22 kJ/mol, and 11 kJ/mol, respectively. It was concluded that the leaching of these vitamins into cooking water was the main pathway for their loss during macaroni preparation.