Performance evaluation of silty sand reinforced with fibres

Triaxial compression tests were conducted to evaluate the response of randomly distributed fibre on the strength of reinforced silty sand. In this study, oil palm empty fruit bunch (OPEFB) fibre was mixed with silty sand soil to investigate the increase of shear strength during triaxial compression. The specimens were tested under drained and undrained conditions with 0.25% and 0.5% content of OPEFB fibres of different lengths (i.e. 15 mm, 30 mm and 45 mm). In addition, OPEFB fibres coated with acrylic butadiene styrene thermoplastic were tested to determine the effect of coating on reinforcement. Inclusion of randomly distributed discrete fibres significantly improved the shear strength of silty sand. Coated OPEFB fibres increased the shear strength of silty sand much more compared to uncoated fibres. Coating fibres increases interface friction between fibre and soil particles by increasing the surface area. Reinforced silty sand containing 0.5% coated fibres of 30 mm length exhibited approximately 25% increase in friction angle and 35% in cohesion under undrained loading conditions compared to those of unreinforced silty sand. The results indicate that the shear strength parameters of the soil-fibre mixture (i.e. Φ′ and c′) can be improved significantly.     

Patterning of porous silicon nanostructures and eliminating microcracks on silicon nitride mask using metal assisted chemical etching

A method for selective formation of reproducible, high fidelity and controllable nano and micrometer size porous Si areas over n-type Si wafers is provided. A 400 nm thick Silicon Nitride layer was used as the mask layer while Platinum and Palladium nanoparticles were deposited over the unprotected areas to obtain porous areas through metal assisted chemical etching process. Nanoparticles were deposited by electroless plating solutions containing H₂PtCl₆ and PdCl₂. Good controls over pore size and depth were obtained with well defined and sharp edges of the patterned areas. The results were compared to porous structures obtained via electrochemical etching process, indicating the superiority of metal assisted etching in terms of its simplicity as well as the ability of Silicon Nitride layer acting as the mask layer.     

Effect of Microstructural Features on Magnetic Properties of High-Carbon Steel

Metallurgical and Materials Transactions A - Industrially produced high-carbon steel has been heat treated in order to obtain various microstructures of the single phase of martensite, bainite,...     

Beta-carotene production within Dunaliella salina cells under salt stress condition in an indoor hybrid helical-tubular photobioreactor

For the cultivation of Dunaliella salina (a green unicellular eukaryote photosynthetic microalga), a 20 L indoor helical-tubular photobioreactor was designed. The inner diameter and the thickness of the PU (polyurethane) tube were 12 and 2 mm, respectively, and its length was 75 m. An open pond was located on the top of the PBR structure and a pump circulated the culture medium from the pond to the tubes. Another part of the tube was connected to an airlift column (which was connected to the bottom of the pond), and the culture medium completed its circulation by moving from the airlift column that connected the closed system (tubular) to the open system (open pond). Eight LED lamps with 10 000 lx were set around the tube and a 2000 lx LED was adjusted on the top of the pond. The culture salinity within the PBR was 1 mol L⁻¹ and four intermittent steps of 0.5 mol L⁻¹ salt stresses were injected into the culture medium. The highest beta-carotene production within this hybrid helical-tubular PBR was 4.85 µg of beta-carotene per mg of dry weight of microalgae at 2.5 mol L⁻¹ salinity.     

Isolation and Identification of Phenanthrene Degrading Bacteria from the Soil around Oil Company of Andimeshk and Investigation of Their Growth Kinetics

Polycyclic aromatic hydrocarbons are particularly important due to large distribution in the environment, high toxicity and their carcinogen and mutagen properties. The purpose of this study was isolation and identification of phenanthrene degrading bacteria from the soil around Oil Company of Andimeshk (Iran) and investigation of their growth kinetics. Sampling from three stations was done at two seasons, spring and summer. Phenanthrene degrading bacteria were isolated from soil using enrichment method. Bacterial identification was performed by biochemical tests and 16S rRNA gene sequencing. Minimum inhibitory concentrations (MIC) were determined at various concentrations of phenanthrene. Bacterial biodegradation rate was determined using HPLC analysis. Finally, the growth kinetics of resistant bacteria was determined with culturing at concentrations of 0.5–0.8 g/l of phenanthrene. According to biochemical and molecular tests Pseudomonas aeruginosa strain SBL, Bacillus cereus strain Z4B-11, Staphylococcus epidermidis, and Micrococcus luteus were identified as phenanthrene degrading bacteria. The results showed that P. aeruginosa SBL and B. cereus Z4B-11 with the greatest amount of MIC are the most phenanthrene resistant bacteria, respectively. These two strains degraded 70% and 50% of phenanthrene after one week of incubation, respectively. The most growth in different concentrations of phenanthrene belonged to P. aeruginosa SBL and B. cereus Z4B-11 while the least growth belonged to S. epidermidis and M. luteus, respectively. It could be concluded that two new strains SBL and Z4B-11 which were isolated in the soil around Oil Company of Andimeshk have relatively high potential to be used for bioremediation of phenanthrene.     

Cane molasses fermentation for continuous ethanol production in an immobilized cells reactor by Saccharomyces cerevisiae

Sodium-alginate immobilized yeast was employed to produce ethanol continuously using cane molasses as a carbon source in an immobilized cell reactor (ICR). The immobilization of Saccharomyces cerevisiae was performed by entrapment of the cell cultured media harvested at exponential growth phase (16 h) with 3% sodium alginate. During the initial stage of operation, the ICR was loaded with fresh beads of mean diameter of 5.01 mm. The ethanol production was affected by the concentration of the cane molasses (50, 100 and 150 g/l), dilution rates (0.064, 0.096, 0.144 and 0.192 h^?1) and hydraulic retention time (5.21, 6.94, 10.42 and 15.63 h) of the media. The pH of the feed medium was set at 4.5 and the fermentation was carried out at an ambient temperature. The maximum ethanol production, theoretical yield (Y_E/S), volumetric ethanol productivity (Q_P) and total sugar consumption was 19.15 g/l, 46.23%, 2.39 g l^?1 h^?1 and 96%, respectively.     

UV-LEDs assisted peroxymonosulfate/Fe<Superscript>2+</Superscript> for oxidative removal of carmoisine: The effect of chloride ion

The performance of UVA-LEDs assisted peroxymonosulfate (PMS)/Fe²⁺ system was evaluated on carmoisine (E122) decolorization. Complete color removal was obtained under the conditions of pH=3.0, PMS=1.5 mM, Fe²⁺=1 mM and 25 min reaction time. UVA-LEDs were preferable compared to conventional UVA lamp in terms of decolorization. The functions of Co²⁺, Cu²⁺, Mn²⁺ and Fe²⁺ were compared and their results showed that Co²⁺ and Fe²⁺ had the highest efficiencies. Moreover, the presence of chloride ion showed a double role in different concentrations in which promotional effect was observed in 100 mM Cl^?<, while inhibitory effect occurred in 1–10 mM Cl^?. However, the high concentration of chloride had no influence on mineralization of E122. The scavenging results demonstrated that the UV irradiation increased the contribution of HO^?. In addition, in the presence of chloride ion, HOCl along with sulfate and hydroxyl radicals were the major oxidative agents.