Sharif Digital Repository

In this study, the effect of nanoclay on the rheological and morphological properties of polyamide 6 (PA6)/acrylonitrile-butadiene-styrene (ABS) blends was investigated. The scanning electron microscopy micrographs showed that with increment in the nanoclay content, the dispersed phase droplets size and their polydispersity index decreased, and the finer and more uniform dispersed phase was obtained. The transmission electron microscopy micrographs of nanocomposites indicated well-dispersed nanoclay tactoids in the polymer matrix produced by exfoliation of the nanoclay in the polymeric blends. Dynamic strain sweep experiments showed that the extent of the linear viscoelastic region is... 

Nano bioactive hydroxyapatite (Ca 10(PO 4) 6(OH) 2, HAp) ceramic powders have been synthesized by a microwave-assisted combustion method. The powders were synthesized using calcium nitrate tetrahydrate (as the source of calcium) and sodium phosphate dibasic anhydrous (as the source of phosphate ions). Glycine, citric acid and urea were used as fuesl. The influence of the fuel type on the structure and morphology of the samples was studied. Results by X-ray diffraction and Fourier-transform infrared spectroscopy showed the formation of hydroxyapatite as a major phase for all the samples. Using the Scherrer formula, the average crystallite size was found to be in the range of 10 to 28 nm.... 

Epoxy-clay nanocomposites were prepared using silane modified montmorillonite. The clay was first purified using a 1-inch hydrocyclon apparatus. The purified clay was modified with various amounts of (γ)-3-aminopropyltrimethoxysilane as a modifier. The synthesized organoclay was mixed and swollen by a mixture of epoxy resin and stoichiometric amount of curing agent at different temperature, mixing time and agitation. Finally, the compounds were cured in an oven at 90 °C for 2 h. The nanostructure materials were characterized using X-ray diffraction and transmission electron microscopy. The X-ray diffraction patterns showed that the impurities and large particles (greater than 5 microns) are... 

The basic goal of this article is to present an abstract system-theoretic approach to morphological filtering and the theory of translation invariant systems which is mainly based on residuated semigroups. Some new results as well as a number of basic questions are also introduced  

Cubic MgO micro-particles with approximately 5-10 μm dimensions were synthesized indirectly from magnesium salt solutions through three consecutive steps, namely: wet chemical precipitation, hydrothermal and thermal dissociation. In wet chemical precipitation step Mg(OH)2 uniform lamellar hexagonal nano-structure with about 30 nm in thickness were synthesized from 0.2 M Mg(NO3)2 • 6H2O solution, subsequent hydrothermal processing of synthesized Mg(OH)2 lamellar hexagonal nano-structure in 10, 20, 30, 60, 120 and 180 min produced 5-10 μm MgCO3 micro-cubes which calcinations of these particles leads to production of the same size MgO micro-cubes. Most pure MgCO3 micro-cubes were synthesized... 

This mini review article, intends to provide the essential information about microemulsion technique as a reliable approach toward the synthesis of zeolitic nano crystallites. The strategy discussed here provides a unique, effective, and potentially general methodology to the preparation of uniform and high purity nano crystallites of template-free zeolitic materials including LTA, faujasite type and other zeolitic-like materials (i.e. zeotype materials). Microemulsion is a reliable approach for controlled synthesis of uniform nano sized zeolitic particulates. On the other hand, the microwave assisted microemulsion technique has the advantages of short reaction time, producing smaller and... 

The physical properties including glass transition temperature and permeability behavior of clay-filled epoxies are reviewed in this chapter. There is no consensus in the literature on how nanoclay affects the α-relaxation temperature in epoxy systems. This perhaps rises from the complexity of nanoclay morphology in polymeric resins and the interphase properties since morphology of nanoclay and interphase characteristics are two key parameters to control the glass transition process in epoxy nanocomposites. In addition, the possible existence of several α-transitions in montmorillonite-filled epoxies due to the existence of several relaxation domains may account for the controversial... 

Cu2O nanocubes, octahedra, spheres and truncated rhombic dodecahedral were prepared and their structural, morphological, and electronic properties were investigated by X-ray diffraction analysis, X-ray absorption near edge structure, scanning electron microscope and transmission electron microscope and X-ray absorption near edge structure. Cu2O nanocrystals were successfully employed to catalyze the 1,3-dipolar cycloaddition reaction for the synthesis of 1,4-disubstituted triazoles. Cu2O nanocubes and octahedral showed the superior catalytic performance in the cycloaddition reaction. These results reveal that crystal-plane engineering of oxide catalysts is a useful strategy for developing... 

Cu2O nanocubes, octahedra, spheres and truncated rhombic dodecahedral were prepared and their structural, morphological, and electronic properties were investigated by X-ray diffraction analysis, X-ray absorption near edge structure, scanning electron microscope and transmission electron microscope and X-ray absorption near edge structure. Cu2O nanocrystals were successfully employed to catalyze the 1,3-dipolar cycloaddition reaction for the synthesis of 1,4-disubstituted triazoles. Cu2O nanocubes and octahedral showed the superior catalytic performance in the cycloaddition reaction. These results reveal that crystal-plane engineering of oxide catalysts is a useful strategy for developing... 

The best usual way in order to diagnosis, control and therapy different kind of Epilepsy is to refer to patient's EEG signals. Usually, in normal conditions of a patient, Epilepsy shows itself through EEG signals in the shape of transient waves. Identification of this waves using human eyes is so difficult that automatic detection methods based on mathematics and signal processing, should have been applied as an auxiliary tool to help physician identify this waves. The most significant transient epileptic waves in EEG are spikes. Up to now, various methods are presented for detection of spikes, but a quantitative and comparative evaluation hasn't been performed. In this work, we suggested a... 

Stoichiometric hydroxyapatite (HA) powder was synthesized by wet method using orthophosphoric acid and calcium hydroxide, as raw materials. In this regard, the time-depending changes of the precipitated particles and effects of heating on them were investigated. The as-precipitated and heated powder samples were examined using field emission electron microscopy (FESEM), XRD and Raman spectroscopy methods. The results revealed that the morphology and size of the precipitated particles change in each stage of the process. After drying, these nanoparticles tend to form small agglomerates. © 2003 Elsevier Science B.V. All rights reserved  

Phase morphology, state of compatibility and various properties of blends of polycarbonate (PC) with bottle-grade and fibre-grade polyethylene terephthalate (BPET and FPET, respectively) were investigated. It was found that these blends have two-phase separated morphology with partial miscibility. Scanning electron micrographs revealed separated domains of PC-rich and PET-rich zones. PC domains appear spherical increasing in size from 2 μm for PC20/FPET80 up to about 5 μm for PC60/FPET40 blend. Further increase in PC content up to 80% caused phase inversion in which FPET appears as finely dispersed domains in continuous PC matrix. Tg of PC-rich phase decreased from 153 deg;C for pure PC down... 

Due to the important role of surface-related properties of NPs in their biological behavior, simple and fast methods that could precisely demonstrate accurate information about NPs' surface, structure and morphology are highly desirable. In this study a set of surface morphological nano-descriptors (size, shape, surface area, agglomeration state, curvature, corner count and aspect ratio) have been defined and extracted from Transmission Electron Microscopy (TEM) images of nanoparticles (NPs) by Digital Image Processing methods. The extracted data represent a thorough description of the surface and morphologies of NPs lying beyond their TEM images and can supply the data required for a... 

Microstructural evolution of the spray atomized and powder thixoformed hyper-eutectic A390 aluminum alloy was investigated. The spray atomized powder revealed homogeneous and very fine silicon particles distribution, due to the rapid solidification of the alloy. The semi-solid powders were extruded into a closed die cavity through a hole for the plastic deformation of the powder particles. A drop forge of 45kg weight at different heights was used in this investigation. Remarkable rearrangement and growth of the silicon rich phase was revealed in the final stage  

We consider translation invariant (TI) operators on Φ, the set of maps from an abelian group G to Ω ∪ {−∞} , called LG-fuzzy sets, where 0 is a complete lattice ordered group. By defining Minkowski and morphological operations on Φ and considering order preserving operators, we prove a reconstruction theorem. This theorem, which is called the Strong Reconstruction Theorem (SRT), is similar to the Convolution Theorem in the theory of linear and shift invariant systems and states that for an order preserving TI operator Y one can explicitly compute Y ( A ), for any A , from a specific subset of Φ called the base of Y . The introduced framework is a general model for the theory of translation... 

In a previous paper we introduced a generalized model for translation invariant (TI) operators. In this model we considered the space, φ of all maps from an abelian group G to ω U {-∞}, called LG-fuzzy sets, where ω is a complete lattice-ordered group; and we defined TI operators on this space. Also, in that paper, we proved strong reconstruction theorem to show the consistency of this model. This theorem states that for an order-preserving TI operator Y one can explicitly compute Y(A), for any A, from a specific subset of φ called the base of Y. In this paper duality is considered in the same general framework, and in this regard, continuous TI operators are studied. This kind of operators... 

Potential applications of the molecularly imprinted polymers (MIPs) demand physical configurations in different size ranges. Nowadays, research on MIPs is focused on the development of new or improved morphologies, which involves control and modification of the different parameters during the synthesis. In this study, the effect of different synthesis conditions on the particle size and morphology is investigated. Carbamazepine-imprinted polymers were prepared using precipitation polymerization under various conditions such as: the amounts of cross-linker and functional monomers, initiator, porogen, temperature and time of polymerization. We studied the polymerization conditions to obtain... 

The effect of substrate temperature on epitaxial growth of Y1Ba2Cu3O7−x film deposited on (100) crystalline lanthanum aluminate (LAO) substrates by RF Sputtering method has been investigated. The crystal mismatch between film and substrate is about 1.6%. The sputtering was carried out in vacuum with base pressure better than 10−5 Torr and 10/20 Pa oxygen/argon partial pressures. Substrate temperature at this condition is about 730 °C based on Bormann–Hammond diagram. As well known, because of the small lattice mismatch between YBCO and LAO, fabricated thin films are not perfectly c-axis and there is tendency to form a/b-axis regions in the film. Due to substantial effects of the density and... 

The morphology of a quaternary blend containing a diglycidyl ether of bisphenol-A (DGEBA), a thermoplastic modifier (PMMA), a phase-separating curing agent (diaminodiphenylmethane, DDM), and a non-phase-separating curing agent (methylenebis(3-chloro-2,6-diethylaniline, MCDEA) was studied as a function of volume fraction of the thermoplastic modifier and fractional concentration of the curing agents in their mixture. It was found that using mixtures of curing agents a co-continuous morphology could be obtained at PMMA concentrations as low as 2.5 volume percent. Using FTIR spectroscopy it was proved that specific interactions are present between PMMA and individual amine curing agents. On the...