Spinodal decomposition of the γ-phase upon quenching in the Ti–Al–Nb ternary alloy system

The γ-TiAl with L1₀ crystal structure shows extensive solubility for Nb at elevated temperatures. Recently (Rios et al., Acta materialia 2009; 57:6243), we have demonstrated that the high-Nb γ-TiAl phase becomes unstable upon rapid cooling into a nano-scale two-phase microstructure. In this paper, using detailed compositional and microstructural analyses, we have demonstrated that this phase goes through a spinodal decomposition that results in the compositionally distinct phases identified as a lower-Nb γ-phase and the h-phase, which is rich in Nb and forms by the ordering of this element in the γ-phase.     

Design of a reversible structure for memory in quantum-dot cellular automata

Complementary metal oxide semiconductor (CMOS) technology has limitations in reducing the area and size of circuits. The disadvantages of this technology include high power consumption and temperature problems. Quantum-dot cellular automata (QCA) is a new technology that can overcome these shortcomings. Reversible logic is technology used to reduce the power loss in QCA. QCA can be used to design memories that require high operating speed. In this paper, we propose a structure for the reversible memory in QCA. The proposed structure utilizes three-layer technology, which has a significant impact on circuit size reduction. The proposed structure for the reversible memory has 63% improvement in cell number, a 75% improvement in area occupancy, and a 60% reduction in delay compared to the previous best structure.     

Preparation,morphological and thermal characterization of novel nanocomposites based on poly (amide-ester-imide) containing amino acid and nano-Mg-doped fluorapatite surface modified with biodegradable diacid N-trimellitylimido-L-leucine

In this investigation, we prepared novel nanocomposites (NC) s based on poly (amide-ester-imide) (PAEI) containing L-leucine moiety and surface modified nano-Mg-doped fluorapatite (Mod-MgFA) with biodegradable diacid, via ultrasound irradiation. First, surface of nanocystalline Mg-doped fluorapatite was functionalized with biodegradable optically active diacid N-trimellitylimido-L-leucine (TML) by ultrasonic irradiation, so as to increase the compatibility and dispersity in the PAEI matrix. After modification via diacid TML, the Mg-doped fluorapatite was altered from a hydrophilic state to an organophilic one. At that time, the obtained functionalized Mod-MgFA was investigated as reinforcing agent for the synthesis of the PAEI NCs. The resulting NCs were characterized by Fourier transform infrared (FT-IR), transmission electron microscopy, field emission-scanning electron microscopy (FE-SEM), X-ray diffraction, and thermogravimetric analysis (TGA) techniques. TGA data showed an increasing in thermal stability of the aforementioned NCs when compared to the neat PAEI. FE-SEM results presented a rather good amount of dispersion of Mod-MgFA in the polymer matrix.     

Extraction of pomegranate (Punica granatum L.) seed oil using superheated hexane

Superheated hexane extraction (SHHE), Soxhlet extraction and cold pressing method were compared for the extraction of pomegranate seed oil. The extraction efficiencies of different temperatures (80, 100, 120 °C), mean particle sizes (0.25, 0.50 and 1.00 mm), and n-hexane flow rates (0.5, 1.0 and 2.0 mL/min) were investigated. The fatty acids profile of the seed oils were quantitatively determined by GC-FID. The optimum extraction temperature, mean particle size, and flow rate were selected as 80 °C, 0.25 mm, and 1 mL/min, respectively. The SHHE showed a higher extraction efficiency (22.18 wt%) within 2 h than Soxhlet extraction (17.94 wt%) for 24 h and cold pressing (4.29 wt%) for 72 h. The fatty acids profile for SHHE was more similar to that obtained by cold pressing method than Soxhlet extraction.     

Diagnostic pre-treatment procedure for simultaneous cyanide leaching of gold and silver from a refractory gold/silver ore

This study investigates the optimization of simultaneous dissolution of gold and silver from a refractory gold ore through determination of pre-treatment stages. Based on the mineralogical studies (thin layer and polished section) and chemical analysis on the ore sample, a “diagnostic leaching” procedure was designed. Results from diagnostic leaching suggest that the most effective pre-treatment agents for gold and silver are ferric chloride and sulfuric acid media, respectively. Optimum conditions for the simultaneous dissolution of gold and silver were determined using a two factorial design technique. Pre-treatments with sulfuric acid and ferric chloride reagents increased the efficiency of the dissolution of gold from 54.7% to 82% and silver from 37.4% to 81.6%.     

Composition and antioxidant and antimicrobial activity of the essential oil and extracts of Stachys inflata Benth from Iran

Composition and antioxidant and antimicrobial activities of essential oil and methanol extract polar and nonpolar subfractions of Stachys inflata were determined. GC and GC/MS analyse of the essential oil showed 45 constituents representing 95.46% of the oil, the major components linalool (28.55%), α-terpineol (9.45%), spathulenol (8.37%) and (2E)-hexenal (4.62%) constituted 50.99% of it. Essential oil and extracts were also tested for their antioxidant activities using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and β-carotene/linoleic acid assays. In the DPPH test, IC₅₀ value for the polar subfraction was 89.50 μg/ml, indicating an antioxidant potency of about 22% of that of butylated hydroxytoluene (IC₅₀ = 19.72 μg/ml) for this extract. In β-carotene/linoleic acid assay, the best inhibition belonged to the nonpolar subfraction (77.08%). Total phenolic content of the polar and nonpolar extract subfractions was 5.4 and 2.8% (w/w), respectively. The plant also showed a week antimicrobial activity against three strains of tested microorganisms. Linalool and α-terpineol were also tested as major components of the oil and showed no antioxidant but considerable antimicrobial activities.