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In this study, the effects of drying temperature and mechanical pressure on the surface structure and dynamical properties of polyaniline (PAni) were studied. PAni was synthesized through the aniline polymerization process in the presence of ammonium persulfate in acidic medium and normal methyl-2-pyrrolidine solution. The obtained solution was dipped on a substrate of quartz glass. Atomic force microscopy (AFM) analysis based on nano-indentation tests were used to determine the values of hardness, Young’s modulus and Poisson’s ratio of the films. The results of the analysis of the scanning electron microscope demonstrated that the surface morphology of the film is changed from a fiber-to-interconnected cross-linked networkby increasing the drying temperature. The transmission electron microscope analysis showed that the diameter of the fibers on the surfaces dried at 318 K and 418 K was 18 and 30 nm, respectively. AFM results showed that the mean surface roughness of PAni film at 318 K without mechanical pressure was 63 nm, while for the film pressed at 5 MPa was less than 35 nm. Thermo-mechanical analysis showed that the glass transition temperature of the PAni film prepared without mechanical pressure and the film pressed at 5 MPa were 386 K and 378 K, respectively. Investigating the temperature dependence and applied pressure on the film surface in determining the viscoelastic properties of the PAni nanostructured film can provide readers with appropriate information about the storage and loss modulus of the film and the activation energy of the polymer layer during the thermal decomposition process.

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Dehydrogenation of alkane to alkene is a key process in petrochemical industry. Propylene has intermediate role to production many industrial polymers. In this research applying oxidative dehydrogenation method for propylene production and CO2 used as oxidant. By use of XRD, Raman, TEM, BET and EDX techniques the results have been analyzed. In XRD and Raman tests anatase phase and Titania nanotubes have been distinguished. TEM confirmed TiNTs with pure structure. Vanadium catalyst with 5% of vanadia synthesized by impregnation method. Adding silicon in support increased thermal stability of catalyst. Raman and XRD method confirmed good distribution of active phase on supports. VSiTi catalyst have 28.31% conversion and 51% selectivity in 550 oC. Improvement in yield of propylene production would be in result of higher surface area and good distribution of vanadia over modified Titania nanotubes.  

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Investigation of Microstructure andAnisotropy of MechanicalProperties of the ARB-Processed Commercial Purity Aluminium with Interpassing Heat Treatment Abstract Accumulative roll bonding (ARB) is a severe plastic deformation (SPD) process that may be defined as multistep rolling process in order to create high strength metals with ultra-fine grained (UFG) in nanometer level. In this study,ARB process with interpassing heat treatment was carried out on the commercial pure Aluminium sheet up to 13 cycles.The variation of microstructure during the cycles of ARB process to access to grains with nanometer dimensions was investigated. In addition, micro-Vickers hardness measurement was carried out throughout thickness of the ARB processed sheets. Eventually, the changes of strength and elongation and also anisotropy of mechanical properties of the sheets during the cycles of process was studied by uni-axial tensile test in 3 directions (roll direction (RD), transverse direction (TD) and direction of 45o toward RD). Keywords: ARB Process, Nanostructure, Micro-Vickers Hardness, Mechanical Properties, Anisotropy.

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Electro-induced hydrophilicity of the Ag/TiO₂ nanostructure has been reported in this study. In this work hydrogen plasma bombarded Ag/TiO₂ nanostructure was created using a sequential process including chemical vapor deposition and plasma bombardment.  X-ray diffraction and X-ray photoelectron spectroscopy were used to analyze structure and chemical states of the sample. The prepared Ag/TiO₂ heterostructure has enhanced visible-light-induced hydrophilicity comparing to pure TiO₂. The electro-induced hydrophilicity of the samples was also examined by creating the comb like electrodes on the prepared Ag/TiO₂. A super-hydrophilic surface was achieved by applying an electric bias voltage on the electrodes.

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We present a micro/nano-machining process to introduce nanostructured poly-silicon layer on the gate region of the pH-sensitive field effect transistors. Decoration of the gate of the field effect transistors by nanostructures plays an important role to improve the sensitivity of the pH-sensitive FETs. Electron beam lithography was exploited to realize the poly-Si nanopillars on the gate surface. Comparison between different micro and nanostructures demonstrates the potential of nanopillars to be utilized on the gate of this device rather than micro-conical structures (different size and shapes) and vertically carbon nanotubes. A high sensitivity of 500 mV/pH has been achieved, through the incorporation of silicon based nanopillars.

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A polypyrrole (PPy) coated polyester fiber was provided by chemically-deposition of PPy on the surface of polyester fiber in the electrolyte of FeCl₃ (as an oxidant) and pyrrole as a monomer. The Scanning Electron Microscopy (SEM) was used for characterization of morphology, size and porosity of synthesized polymer. The seed like PPy particles (50-150 nanometers) are observed according to the SEM results. The PPy fiber was employed to extraction of volatile organic compounds (VOCs) in sesame samples as an extraction agent. An experimental design was utilized to optimize operational parameters that affect the analysis of VOCs in sesame samples using headspace solid phase microextraction (HS-SPME) in the pre-concentration step. Some parameters including, extraction time and temperature were optimized. Gas chromatography-flame ionization detection (GC-FID) was used for separation, detection and quantitation of VOCs. Results show that PPy modified polyester fiber is provided fast and easy by chemical method and is suitable for the successful extraction of the VOCs from sesame samples.

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Accurate determination of the electro-elastic fields of quantum nanostructures within piezoelectric media is an important issue for realizing the electro-mechanical behavior of these nanostructures. In this paper, the governing partial differential equations corresponding to piezoelectric media containing quantum nanostructures are presented and subsequently, generalized analytical solutions based on Fourier series technique are developed for determination of the coupled electro-elastic fields in transversely isotropic piezoelectric barrier due to periodically distributed quantum nanostructures. The electro-elastic couplings of the piezoelectric barrier as well as the interactions between the quantum nanostructures are exhibited within the framework of the presented analytical solution. It is observed that no electric field and no electric potential will be induced anywhere in the medium for periodic distribution of quantum wires. The presented analytical solution is capable of treating different shapes and geometries of quantum wires/quantum dots. The electro-elastic fields of various shapes of sections of quantum wires and different geometries of quantum dots are studied and the effects of the geometry of periodically distributed quantum nanostructures are demonstrated. The results show that geometry of quantum nanostructures may highly affect the induced electro-elastic fields and therefore, accurate determination of the geometry of quantum nanostructures as well as the induced electro-elastic fields would be essential for employment of these nanostructures in different fields of research and technology.

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In this paper, a three-dimensional finite element model is proposed for estimating Young’s modulus of fullerene nanostructures. The model is based on the assumption that the fullerenes, when subjected to loading, behave like space-frame structures. The bonds between carbon atoms are considered as connecting load-carrying members like beams under axial, bending and torsion loadings, while the carbon atoms as joints of the members. To create the finite element models, nodes are placed at the locations of carbon atoms and the bonds between them are modeled using three-dimensional elastic beam elements. The elastic modulus of beam elements is determined by using a linkage between molecular mechanics and continuum mechanics. In order to evaluate the Young’s modulus, the spherical shell theory is also utilized. Compression loading on the fullerene is considered and the load – displacement variation is obtained. The effect of diameter on the elastic modulus of fullerenes nanostructures has been studied and it is observed that by increasing the radius of fullerenes, their elastic modulus decreases. After studying the properties of perfect fullerenes, the Young’s modulus of different defective fullerenes is also determined.

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The most successful ‘‘top–down’’ approach to produce bulk ultra-fine grained or nanostructured materials involves the use of severe plastic deformation (SPD) processing. The amount of higher effective plastic strain per pass plays a key role on the final microstructure of SPD processed samples. In the present study the numerical experiments of the combination of the equal channel angular pressing (ECAP) and simple shear extrusion (SSE) as a new process entitled “planar twist channel angular extrusion (PTCAE)” was performed based on the Response Surface Methodology (RSM), as a statistical design of experiment approach, in order to investigate the effect of parameters on the response variations, achieving the mathematical equations, predicting the results to impose higher effective plastic strain values. Α and ϕ angles, radius and friction coefficient was imposed as the input parameters while average, minimum and maximum effective strain and maximum load was imposed as the output parameters. Governing regression equations obtained after analysis of the simulation data by Minitab software. Optimum process parameters are: α=450, Φ =450, r=2 mm and µ=0.1. Verification of the optimum results using simulation experiment was done. Good agreement between simulation, experimental and optimization was occurred.

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Abstract: Introduction: Solidification and stabilization of heavy metal contaminants is recognized as the technology to prevent transfer of contaminants to the lower layers of soil and groundwater. A noticeable increase in distribution of heavy metal contaminants in recent years highlights the importance of effective methods for engineering disposal of industrial wastes. The most important challenge ahead of this endeavor is perhaps the determination of right framework and mechanism of action. Precise mechanism of mobility of contaminants can be grasped by gaining accurate and comprehensive understanding about system behavior and evaluating it from the nano- and micro-structure perspectives. Nano- and micro-sized clay particles can be used effectively as adsorbents of many contaminants (e.g. heavy metal ions and organic compounds) in sewage and wastewater. Moreover, as clay soils have high cation exchange capacity (CEC), they provide appropriate conditions for cation exchange and create considerable capacity to retain heavy metal contaminants. In spite of conducting extensive studies on stabilizing contaminants by the use of cement, inadequate attentions have been paid to microstructure study of interaction process of clay particles, heavy metal ions, and cement, specifically in cement hydration process in different time intervals. Based on this, the present research aims to study the interaction process of clay particles, heavy metal contaminants, and cement over time from the perspective of microstructure. This include the investigation of the effect of presence of heavy metal on cement hydration process and formation of nano-structure calcium silicate hydrate (C-S-H). Material and method: In this study, the behavioral tests were conducted on natural clay soil collected from the Qazvin Plain, Iran. The purpose of this selection was to determine geotechnical-environmental properties and contaminant adsorption-retention capability of samples of natural clay with average specific surface area and CEC and the effects of natural clay on the solidification and stabilization process. The majority of experiments of this study were conducted based on ASTM standards and geotechnical-environmental test guidelines of McGill University (Canada). Density and pH of clay samples were determined in accordance with ASTM, D854 and ASTM, D4972 standards. Soil carbon content was determined by titration. Specific surface area (SSA) of the soil was measured using EGME solution. The cation exchange capacity (CEC) of the soil was determined using 0.1 M barium chloride solution. Meanwhile, different concentrations of heavy metal contaminant (zinc) and different percentages of Portland cement were added to natural clay. The interaction process was analyzed experimentally by examining pH changes and evaluating microstructure study (XRD). Result and discussion: According to laboratory results obtained in this study, the high specific surface area of C-S-H nanostructure improves the adsorption characteristics and leads to better filling of pores. It also improves the retention capability by decreasing the mobility of heavy metal contaminants via encapsulation of their ions (solidification). The results show that formation of C-S-H nanostructure improves absorption features due to high specific surface area and decreases mobility of the heavy metal ions through their encapsulation (solidification). In addition, the presence of the heavy mental contaminant (zinc) reduces formation of C-S-H nanostructure so that the presence of 25 cmol/kg-soil of heavy metal ion (zinc) decreases peak intensity of C-S-H nanostructure about 160 CpS.

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The NLCs are potent carriers for lipophilic bioactive compounds. The NLC:maltodextrin (6:10) solution at the inlet temperatures of 110 or 180 °C, and the feed flow rate of 5 or 15 mL/min was spray-dried and the powders characteristics were evaluated. The SEM micrographs showed the particle morphologies of hollow spheroids with smooth surfaces. The powder production yields as high as 66% was achieved. The sizes of NLC particles after the redispersion of the spray-dried powders shifted to higher amounts, but were below the acceptable size of NLC systems. The measurement of flowability indices such as Carr’s compressibility index, Hausner ratio, and angle of repose showed that the samples were categorized as the powders with good flowability. The results of this study revealed that NLC systems can be successfully spray-dried by using maltodextrin as the excipient without any drastic changes in the particle size.

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Abstract Solid lipid nanoparticles and nanostructure lipid carriers were used to entrap curcumin and broaden confined knowledge of application of nanocarriers as the functional ingredients in food sectors. The effect of lipids ratio (GDS /GMS), kind of nanocarrier (SLN and NLC) and curcumin concentration (0, 0.25 and 0. 5 % (w / w) of emulsion) on the qualitative characteristics of nanocarrier were evaluated. Based on the results the massive physical structure of Curcumin and also increases the viscosity of the material dispersed phase in the presence of active, loading Curcumin in the developed nanocarrier led to significant (p<0.05) increase in nanoparticles size. DSC analyses showed that the crystalline states of produced nanocarriers were less ordered than pure materials and indicated that the curcumin was well incorporated in lipid matrices. However, our pretest showed that concentration of 5% Glycerol distearate and 0.25% Curcumin was the optimum for the production of Solid lipid nanoparticles and nanostructure lipid carriers.

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The electrical properties of nanostructured piezoelectric materials have attracted the attention of many researchers in the last decade. These features are used in piezoelectric micro-sensors. Mechanical propulsion is usually the result of contact between a piezoelectric surface and a foreign object. In this paper, the effect of mechanical propulsion using an air wave (sound) or vacuum on a silicon diaphragm is investigated. The local stresses created on the diaphragm due to the impact of an air wave have a significant effect on the peak-to-peak voltage of the piezoelectric sensor, which can be measured by measuring changes in this parameter. To investigate this, a micromachined diaphragm of silicon was examined and it was found that fabricating a piezoelectric sensor on a thin and patterned diaphragm could increase the peak-to-peak voltage by about 1.3 times. Detection of these stresses using piezoelectric material layered on the thin and formable diaphragm can act as a piezoelectric microphone or a barometer that the presence of microstructures on the diaphragm will increase their sensitivity.