Chemical compositions of the marine algae Gracilaria salicornia (Rhodophyta) and Ulva lactuca (Chlorophyta) as a potential food source

BACKGROUND: The nutritional compositions of two edible red (Gracilaria salicornia) and green (Ulva lactuca) seaweeds were determined to evaluate their possible uses as potential food ingredients. RESULTS: In general, these species contained limited amounts of lipids ranging between 0.99 and 2.00 g 100 g^?1 dry weight) and considerably high amount of minerals, especially in G. salicornia (38.91 g 100 g^?1 d.w.). The crude protein values varied between 9.58 and 10.69 g 100 g^?1 d.w. Amounts for total amino acids were 889.78 ± 22.64 mg g^?1 protein d.w. in G. salicornia and 543.3 ± 15.14 mg g^?1 protein d.w. in U. lactuca. The most abundant fatty acids were C12:0, C16:0, C20:4 ω6 and C22:5 ω3, in addition to C18:1 in G. salicornia. Both seaweed species were balanced sources of ω3 and ω6 fatty acids with a ratio of ω6/ω3 that varied between 1.2 and 1.17. Between the seaweeds investigated, high levels of K (2414.02‐11 380.06 mg 100 g^?1 d.w.) were observed and the amounts of Ca, Na and Fe were higher than those reported for land plants. CONCLUSIONS: Thus, G. salicornia and U. lactuca may be utilised as value‐added products for human nutrition purposes. Copyright © 2012 Society of Chemical Industry     

Electrochemically synthesized polypyrrole/MWCNTs-Al2O3 ternary nanocomposites supported Pt nanoparticles toward methanol oxidation

As known, a good support enhances the activity and durability of any catalyst. In the current study, polypyrrole (PPY)/nanocomposite (MWCNTs and Al₂O₃) films were fabricated by electrochemical polymerization of pyrrole solution with a certain amount of nanoparticles on titanium substrates and were used as new support materials for Pt catalyst. The modified electrodes were characterized by Fourier transform infrared (FT-IR) spectroscopy, field-emission scanning electron microscopy (FE-SEM) and energy dispersive X-ray analysis (EDX) techniques. High catalytic activity and long-time stability toward methanol oxidation of Pt/PPY–MWNTs-αAl₂O₃ catalyst have also been verified by cyclic voltammetry results and chronoamperometric response measurements. This catalyst exhibits a vehemently high current density (345.03 mA cm^?2) and low peak potential (0.74 v) for methanol oxidation. Other electrochemical measurements (electrochemical impedance spectroscopy (EIS), CO stripping voltammetry and Tafel test) clearly confirmed that Pt/PPY–MWNTs-αAl₂O₃/Ti electrode has a better performance toward methanol oxidation compared to the other electrodes and that can be used as a promising electrode material for application in direct methanol fuel cells (DMFCs).     

The effect of Al2O3 nano additions on failure of GFRP plate with two parallel pin loaded holes

Journal of Mechanical Science and Technology - The aim of this study is to scrutinize the effect of nano-additions on failure modes and loads of glass-epoxy laminate subjected two parallel...     

微波辅助燃烧法制备镁铝尖晶石纳米粉体的研究

Stoichiometric MgAl2O4 spinel nanoparticles were synthesized by microwave assisted combustion reaction from aluminium nitrate nanohydrate(Al(NO3)3.9H2O) and Sol-Gel prepared magnesium hydroxide(Mg(OH)2) in the presence of urea((NH2)2CO) as a fuel,in about 20 min of irradiation.X-ray diffraction(XRD) studies reveal that mi-crowave assisted combustion synthesis route yields single-phase spinel nanoparticles with larger crystalline size(around 75 nm) than other conventional heating methods.Scanning electronic microscope(SEM) images show nanoparticles with spherical shape and homogenous morphology.The surface area measurements(SBET) show crystals with 2.11 m2/g and 0.0033 mL/g pore volume.     

A discrepancy between observed and predicted NATM tunnel behaviors and updating: a case study of the Sabzkuh tunnel

Bulletin of Engineering Geology and the Environment - The 11 km long Sabzkuh water conveyance tunnel is under construction using conventional and tunnel boring machine tunneling techniques...     

Possibility of using chemical fertilizers instead of 9K medium in bioleaching process of low-grade sulfide copper ores

The possibility of applying chemical fertilizers as a source of nutrients for bacterial growth in bioleaching process was investigated. In the first part of the experiment the nutrient content of four sulfide copper ore samples was determined. The results confirmed that the amount of calcium, magnesium and sulfur were sufficient to support bacterial growth, whereas nitrogen, phosphorous and potassium were not sufficient. Therefore, N, P, and K from a chemical fertilizer source were applied to the sulfide copper ores to make a cost-effective bioleaching process. According to shake flask experiments by using mesophilic, iron-sulfur oxidizing bacteria, bacterial activity and copper recovery in some proposed media was satisfactory compared to 9K medium. Additionally, potassium had positive effect on the copper ore bioleaching while NO₃⁻ and Cl⁻ had inhibitory effect on the bacterial activity.     

Electron beam lithography and ion implantation techniques for fabrication of high-Tc Josephson junctions

Established semiconductor process technologies are demonstrated to be suitable for the fabrication of high temperature superconductor (HTS) Josephson junctions. Single YBCO bridges were modified by local oxygen ion irradiation through a narrow slit in a PMMA mask which was formed by electron beam lithography. The influence of slit dimension and irradiation dose was investigated. The critical current and normal resistance ot the modified microbridges can be controlled by these two parameters. Proximity coupling across the modified region is observed up to a slit width of 250 nm. When exposed to microwave irradiation the microbridges exhibited Shapiro steps. In dc SQUIDs a voltage modulation as a function of an applied magnetic flux is observed.     

Fast recovery of non‐fickian moisture absorption parameters for polymers and polymer composites

Moisture absorption is known to detrimentally affect the mechanical integrity and durability of polymeric materials. Consequently, accurately characterizing the moisture diffusion into these materials is critical when predicting their service life behavior. The hindered diffusion model (HDM), that is, Langmuir‐type absorption, has been widely used to successfully describe both Fickian and anomalous absorption behavior of polymeric materials. In this article, proper use of both exact and approximate solutions of the HDM model is illustrated on two material systems: nanoclay/epoxy composites and thin epoxy laminates. A parameter recovery technique, based on a modified version of the steepest descent search, is shown to accurately recover all absorption parameters simultaneously from experimental data. The absorption behavior predicted by the recovered parameters is then validated by long‐term absorption data not used in the recovery process. The errors induced by approximate solutions are observed to be material‐dependent and could be substantially larger compared to the exact solution. In addition, a novel method to computationally accelerate the recovery of the absorption parameters is proposed. The new technique uses the approximate absorption parameters as the initial guess. It is shown that this approach substantially reduces the computational effort by decreasing the number of iterations without compromising from accuracy. POLYM. ENG. SCI., 57:921–931, 2017. © 2016 Society of Plastics Engineers     

Hybrid blind robust image watermarking technique based on DFT-DCT and Arnold transform

Multimedia Tools and Applications - In this paper, a robust blind image watermarking method is proposed for copyright protection of digital images. This hybrid method relies on combining two...     

Thermo-mechanical constitutive modeling of unsaturated clays based on the critical state concepts

A thermo-mechanical constitutive model for unsaturated clays is constructed based on the existing model for saturated clays originally proposed by the authors.The saturated clays model was formulated in the framework of critical state soil mechanics and modi fi ed Cam-clay model.The existing model has been generalized to simulate the experimentally observed behavior of unsaturated clays by introducing Bishop’s stress and suction as independent stress parameters and modifying the hardening rule and yield criterion to take into account the role of suction.Also,according to previous studies,an increase in temperature causes a reduction in speci fi c volume.A reduction in suction(wetting)for a given con fi ning stress may induce an irreversible volumetric compression(collapse).Thus an increase in suction(drying)raises a speci fi c volume i.e.the movement of normal consolidation line(NCL)to higher values of void ratio.However,some experimental data con fi rm the assumption that this reduction is dependent on the stress level of soil element.A generalized approach considering the effect of stress level on the magnitude of clays thermal dependency in compression plane is proposed in this study.The number of modeling parameters is kept to a minimum,and they all have clear physical interpretations,to facilitate the usefulness of model for practical applications.A step-by-step procedure used for parameter calibration is also described.The model is fi nally evaluated using a comprehensive set of experimental data for the thermo-mechanical behavior of unsaturated soils.