Identification of active peptides from backbones of Nemipterus japonicus and Exocoetus volitans by electrospray ionisation–mass spectrometry

In our present investigation, Nemipterus japonicus and Exocoetus volitans backbone protein were hydrolysed by proteases like trypsin and pepsin, respectively. The protein hydrolysates were purified by different chromatographic methods, and the resulted purified peptides were analysed for their amino acid sequences by electrospray ionisation–MS/MS. The analysis of peptides showed sequences as Gly‐His‐Met‐Ser (451.8 Da) and Leu‐Glu‐Val‐Lys‐Pro (596.9 Da) for N. japonicus and E. volitans muscle, respectively. The presence of hydrophobic amino acids contributes more to the antioxidant activities of peptides than other amino acids. Moreover, sequence of amino acids in peptides plays an important role in their antioxidant activities.     

Dynamic analysis of functionally graded material cylinders under an impact load by a mesh-free method

In this paper, dynamic analysis of functionally graded material cylinders is carried out under an impact load. In this analysis, MLS shape functions are used for the approximation of the displacement field in the weak form of motion equation and essential boundary conditions are imposed by the transformation method. The resulting set of differential equations is solved using central difference approximation. The mechanical properties of the cylinders are assumed to be variable in the radial direction. Effects of the geometrical dimensions of the cylinders and the exponent of material volume fraction on the natural frequencies are investigated by the proposed model and FEM. Then the response of the cylinders to an impact load is determined by the proposed model, and effects of the above-mentioned parameters on the stress wave propagation is investigated.     

Grey is the new RGB: How good is GAN-based image colorization for image compression?

Multimedia Tools and Applications - GAN-based image colorization techniques are capable of producing highly realistic color in real-time. Subjective assessment of these approaches has demonstrated...     

Synthesis, Spectral Characterization and Biocidal Activity of Thermally Stable Polymeric Schiff Base and Its Polymer Metal Complexes

The polymer metal complexes of transition metal ions Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) with a new polymeric Schiff base containing formaldehyde and piperazine moieties have been synthesized by the condensation and characterized by elemental analyses, infrared spectra, electronic spectra, magnetic susceptibility measurements and thermogravimetric analyses (TGA). The results of the electronic spectra and magnetic moments indicate that the polymer–metal complexes of Mn(II), Co(II) and Ni(II) have octahedral geometry, while the complexes of Cu(II) and Zn(II) show square planar and tetrahedral geometry, respectively. The analyses of the thermal curves of all the polymer metal complexes show better thermal stability than the polymeric Schiff base. All compounds show excellent antibacterial as well as antifungal activity against three types of bacteria and two types of fungi. The antimicrobial activities were determined by using the agar well diffusion method with 100 μg/mL concentrations of polymer metal complex.     

Effect of grain refinement on the microstructure and tensile properties of thin 319 Al castings

The structural examinations and tensile properties of thin-section Al castings (319 Al alloy) have been investigated by applying a pattern with different cross sections (2–12 mm). Al–5Ti–1B and Al–5Zr grain refiners were added to the molten Al alloy to produce different levels of Ti (0.01%, 0.05%, 0.1% and 0.15%) and Zr (0.05%, 0.1%, 0.2%, 0.3%, 0.4% and 0.5%) in the castings. From macrostructural studies, it was found that Al–5Zr is less effective in grain refining of 319 alloy in comparison with Al–5Ti–1B master alloy. The optimum levels of grain refiners were selected for determination of tensile properties. T6 heat treatment was applied for selected specimens before tensile testing. Further structural results also showed that thinner sections are less affected by grain refiners. This observation was found to be in a good agreement with tensile test results, where tensile properties of the base and grain refined alloys did not show considerable differences in thinner sections (<6 mm).     

Effects of hydrogen level and cooling rate on ultimate tensile strength of Al A319 alloy

The present study investigated the effects of initial Hydrogen level and cooling rate on ultimate tensile strength of commercial Al-A319 alloys. Three hydrogen levels (0.01, 0.2, and 0.41 mL/100 grams of melt) and five cooling rate were studied. Total of 45 tensile test bars was prepared (three hydrogen levels × five cooling rate × three repeats). The UTS of the samples was determined though uniaxial tension tests. Furthermore, the microstructures of the samples were studied by standard metallographic technique and image analysis software. Finally the relationship between UTS and microstructurai features—SDAS and fraction of porosity (Fp%)—of the alloys was investigated. Results of tensile test revealed: (i) UTS of the alloy decreased with increasing of hydrogen level or decreasing of cooling rate and (ii) Increasing of cooling rate beyond a certain value increased the UTS of the alloy significantly. Results of image analysis showed that the Fp% increased with increasing of hydrogen level and decreasing of cooling rate. Finally a Matrix Index [= ?SDAS (μm) ? 68.7 Ln (Fp%) + 275] was defined to correlate the tensile strength and microstructurai features of the alloy. It was shown that the UTS of the alloys had a linear dependence on matrix index according the below equation: $UTS(MPa) = 0.916M.I. + 265.17R^2 = 0.95$      

An investigation of different gas injection scenarios as enhanced condensate recovery method in a naturally fractured gas-condensate reservoir

In gas condensate reservoirs, when the bottom hole pressure falls below the dew point pressure condensates are formed. This causes hydrocarbon liquid saturation around the well bore region. This phenomenon is called condensate blockage or condensate banking. Condensate recovery reduction due to condensate banking near the well bore region is an important problem in gas condensate reservoirs. The common method to prevent the condensate banking is gas cycling (reinjection of produced dry gas) into the reservoir that can contribute to the condensate vaporization, thus increasing the condensate recovery factor. The objective of this study was to find a suitable replacement for gas cycling. For this purpose, an investigation on the effects of injection of different types of gases (CO₂, N₂, and C₁) on enhance condensate recovery factor and pressure maintenance were performed. This research was done on one of the Iranian gas condensate reservoirs through a compositional simulator. The two-parameter Peng-Robinson equation of state (EOS) and Lohrenz-Bray-Clark correlation were used to model reservoir fluid properties through regression on the pressure-volume-temperature (PVT) experimental data. A fracture network was distributed over the reservoir, so a dual porosity/dual permeability model was selected for better evaluation of the fracture system. Then, various scenarios of natural depletion and CO₂, N₂, C₁, and gas cycling injection were studied. The results showed that CO₂ injection scenario being associated with the highest efficiency compared to that of other gases.     

Synthesis and characterization of slow‐release nitrogen fertilizer with water absorbency: Based on poly(acrylic acid‐acrylic amide)/Na‐bentonite

A novel slow‐release nitrogen fertilizer with high‐water absorbency (SRNFWA) was prepared by cross‐linking poly (acrylic acid‐acrylic amide)/bentonite and urea. The synthesis conditions were studied systematically and optimized by using the response surface methodology (RSM). Meanwhile, the effects of the concentration of cross‐linker, initiator, bentonite, and degree of neutralization of acrylic acid on WA were investigated. The SRNFWA was characterized by Fourier transform infrared (FTIR) spectroscopy, elemental analysis, and scanning electron microscopy (SEM). The results of SEM showed the undulant and coarse surface, facilitated the permeation of nutrition into the polymeric network. We also investigated the slow release property and release mechanism of the nitrogen from the network structure, and the WA in different external solutions. The released characteristic of nitrogen was less than 15% by the third day and reached up to almost 75% after 30 days in distilled water. The WA was 700 g g^?1 and 150 g g^?1 in distilled water and 0.9 wt % NaCl solutions, respectively. These studies exhibited the excellent slow‐release property and WA capacity of this polymer in 0.9 wt % NaCl solution and could be quite effective in improving the utilization of fertilizer and its water retention capacity simultaneously. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012