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Microorganisms and plants have high potential for reducing the metal (biosynthesis of nanoparticles) through their metabolic pathways. Apart from the environmental benefits of biosynthesis of nanoparticles, there is the opportunity for production of nanomaterial with new properties in this method. In this study, the fruit aqueous extract of Capparis spinosa L. was used for synthesis of nanoparticles. To evaluate the reducing potential of plant, total phenolic content and antioxidant activities of both aqueous and ethanolic extracts were measured by DPPH and FRAP methods. The aqueous extract showed a lower antioxidant activity than the ethanolic extract; however, it had high potential to reduce the free radicals and metal ions. After preparing the extract, for phytosynthesis of silver nanoparticles, 2 ml of extract was added to 4 ml of 1 mM silver nitrate. The extract was used as a reducing and stabilizing agents of the nanoparticles. The effect of determining parameters for optimizing synthesis of nanoparticles such as: pH of reaction, the amount of extract, concentration of metal ion and time of reaction were evaluated using Ultraviolent-Visible (UV-Vis) spectroscopy and Transmission Electron Microscopy (TEM) .The spectrum of Surface Plasmon Resonance (SPR) of silver nanoparticles showed the maximum absorbance at 415 nm. Fourier Transform Infrared (FT-IR) spectroscopy was used to identify the possible functional groups involved in the synthesis of silver nanoparticles. The Results showed that the nanoparticles were spherical shape and the size of them were about 8-12 nm.

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Enzymes of marine organisms are ideal candidates for biomonitoring of pollution in marine environments. For the widespread use of enzymes in industrial processes, carried out under certain physico-chemical conditions, their stability must be improved. In this study, for the first time, chitosan nanoparticles were used as matrices for augmenting the stability of Penaeus vannamei (Whiteleg shrimp)-derived purified proteases against metallic ions. For the electrostatic binding of the enzyme to the chitosan nanoparticles, the protein solution at a concentration of 7mg/ml was added to the nanoparticles, and incubated for 4 hours at 10°C. After 3 times rinsing with phosphate buffer of pH=7.5, the nano-enzyme was dissolved in 1ml phosphate buffer, and used for further studies. The results of this study showed that Fe²⁺ and Mn²⁺ significantly increased the enzyme activity, whereas a strong inhibitory effect was observed in the presence of Cd²⁺, Hg²⁺, Co²⁺, Ni²⁺, Cu²⁺ and Zn²⁺, and a weak inhibitory effect in the presence of Na⁺ and K⁺. The immobilized enzyme exhibited greater resistance to metal ions than its free counterpart. The free enzyme was susceptible to the presence of metal ions, and with the increment of their concentrations, enzyme activity declines. From this nexus, it could be inferred that the high stability of immobilized enzyme is due to the presence of chitosan nanoparticles. Stability retention of the immobilized enzyme at high concentrations of metal ions indicates the efficacy and utility of the immobilization method in industrial enzyme technology.

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Gobiidae family fishes play a significant role in coastal ecosystems with mud beds and mangrove ecosystems and also play a key role in the food chain in these areas. They are known as a heavy metal biomarkers. The aim of this study was to investigate the metals cadmium, lead and nickel in the muscle of two species including Cryptocentrus cyanotaenia in Hormoz Island and Boleophthalmus dussumieri in the Bandar Kamir. A total number of 30 fishes, samples for each species were collected from selected area and after biometrics and preparation and digestion steps to determine the concentration of nickel, cadmium and lead metals were analyzed by atomic absorption spectrometry. In this study, comparisons were made between the concentration of metals with a maximum of 13.10±1.88 and a minimum of 2.85±1.20 µg/g, respectively for  lead and cadmium in the muscle of B. dussumieri. The highest and lowest values ​​of 12.13±1.96 and 2.86±0.83 respectively were recorded for lead and cadmium in C. cyanotaenia muscle. By examining the correlation between the concentrations of metals in the muscle of the species, it was found that there is a positive and significant relationship between the concentration of metals in the muscle and their biometry (total length and total weight). The results showed that the studied Gobiidae family fish are suitable biomarkers for nickel, cadmium and lead metals.
 

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Tube spinning or flow forming process is used for manufacturing of seamless tubes widely put into service in advanced industries. The ideal flow for materials entering the deformation zone in this process is extrusion-type flow in axial direction. Very localized deformation zone which is confined by outer materials and forming tools is very important aspect of this process. Therefore, development of defects during the deformation process with undesirable flow of materials can be easily occurred. The main reason of undesirable flow of materials is choosing inappropriate process parameters which results in arising various geometrical and dimensional defects. In this paper, the effects of process parameters on formation and growth of different defects and their correlations with material flow and forming forces in tube spinning of AA6061 was investigated by using design of experiment (DOE) method. The results of experiments show that by applying the optimized values of reduction and feed rate per revolution, these defects can be controlled. Also, by comparing the experimentally measured and theoretically calculated forming forces it can be shown that the larger the deviation of measured forces from calculated ones gets the more severe formation of defects and undesirable materials flow becomes.

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In this research, three-layered composite of brass-IF steel-brass was fabricated by cold roll bonding process (CRB) and formability of composite were investigated. Due to high work hardening of composite during rolling process, specimens were heat treated at annealing temperatures at 500°Ϲ through 700 °Ϲ for 10 min. Formability properties of composite were investigated by using tensile, anisotropy and Erichsen tests. The results showed that, heat treatment after rolling resulted in occurrence of recrystallization phenomenon in composite, consequently a reduction tensile strength and rising strain hardening rate. Dome height created by Erichsen test prior to heat treatment was 10/53 mm, by annealing composite at 500℃, Dome height reached at 14.62 mm. By increasing annealing temperature to 600℃ and owing to relatively high stacking fault energies of IF steel, recrystallization solitary occurred in brass layer. Nevertheless, as a result of upward trend of annealing temperature up to 650℃ as well as resultant driving force, recrystallization occurred in all layers and gradient of formability properties increased. As at 700℃, recrystallization phenomenon was completed in the composite and dome height was peaked at 17/29 mm. Moreover, by increasing annealing temperature, normal anisotropy and planer anisotropy respectively increased and decreased. Anisotropy properties of composite in comparison with brass and IF steel during complete recrystallization, it was clear that production of brass-IF steel-brass composite caused to improve normal anisotropy in brass and reduce negative effects of planer anisotropy in IF steel.