Papers by Author: Nazanin Farhadyar

Abstract: In the emphasis on knowledge as a key competitive factor in the global economy, corporations may be overlooking a major element customer knowledge. Customer knowledge management (CKM) creates new knowledge sharing platforms and processes between companies and their customers. Customer education is one of the best ways of Customer knowledge management. Despite companies growing interest for customer education and the recent awareness in marketing literature of this concept, research on customer education remains relatively scarce. In this research a model which details the relationships between customer education and customer satisfaction was proposed and validated for nanofood product. The existence of two mediating variables was unveiled: product usage and product-usage related knowledge and skills. The experimental fieldwork was conducted in partnership with nanofood companies and their customers. In this research, clear evidence has been provided that customer education positively impacts on customer satisfaction and that specific mechanisms explain such effects.

Abstract: Magnetic oxide nanoparticles with proper surface coatings are increasingly being evaluated for clinical applications such as hyperthermia, drug delivery, magnetic resonance imaging, transfection and cell/protein separations. In this work, we investigated synthesis, magnetic properties of silica coated metal ferrite, (CoFe₂O₄)/SiO₂ and manganese doped cobalt ferrite nanoparticles (Mn_x-Co_1-xFe₂O₄ with x = 0.02, 0.04 and 0.06)/SiO₂ for possible biomedical application. All the ferrites nanoparticles were prepared by co-precipitation method using FeCl₃.6H₂O, CoCl₂.6H₂O and MnCl₂.2H₂O as precursors, and were silica coated by the Stober process in directly ethanol. The composition, phase structure and morphology of the prepared core/shell cobalt ferrites nanostructures were characterized by powder X-ray diffraction (XRD), Fourier Transform infra-red spectra (FTIR), Field Emission Scanning Electron Microscopy and energy dispersive X-ray analysis (FESEM-EDAX). The results revealed that all the samples maintain the ferrite spinel structure. While, the cell parameters decrease monotonically by increase of Mn content indicating that the Mn ions are substituted into the lattice of CoFe₂O₄. The magnetic properties of the prepared samples were investigated at room temperature using Vibrating Sample Magnetometer (VSM). The results revealed a strong dependence of room temperature magnetic properties on (1) doping content, x; (2) particle size and ion distributions.

Abstract: In the past decade, preparation of low-dimensional semiconductor nanostructures has become a hotspot of materials research because of their attractive optical and electrical properties. Semiconductor nanoparticles have found wide spread application in varied fields of engineering. Since, p-type semiconductors, copper sulfides (Cu_1.96S) were used in solar cells, optical filters and supersonic materials. In this work, we report on the synthesis of Cu_1.96S semiconductor nanocomposites in the presence of PVP via a wet chemistry process and then covered by a layer of gold nanoparticles. Formation of a pure CuS phase, in the presence of a PVP nanostructure was confirmed by X-ray diffraction (XRD) analysis. Size and morphology of as-prepared nanostructure were studied using Transmission Electron Microscopic (TEM) images. The results revealed the formation of a dense Cu_1.96S and roughly spherical nanoparticles with an average diameter of about 25-35 nm coated homogeneously with gold nanoparticle. Room temperature photoluminescence (PL) measurements of the prepared samples showed enhanced blue-green emission (350 to 600) nm and red emission from 600 to 800nm.

Abstract: In this paper, we report enhanced blue green emission of hexagonal shaped ZnO nanorods (NRS) grown via a simple hydrothermal method and silica coated then by using tetraethoxysilane (TEOS). The composition and structural characteristic of the prepared samples were studied by X-ray diffraction (XRD), Field Emission Scanning Electron Microscopy and Energy Dispersive X-ray analysis (FESEM-EDAX). The results revealed well crystallized hexagonal structure possessing a perfect and ideal growth habits of wurtzite zinc oxide grown along the [00 direction in preference in both the cases. Optical properties and quality of the prepared ZnO and silica coated ZnO nanorods were examined by UV-visible and FTIR spectroscopy. Photoluminescence (PL) spectra were used to study ZnO and silica coated ZnO nanorod electronic structure, which resulted in an obvious enhanced blue-green emission for ZnO nanorod and an intense red emission with a very low UV intensity for the silica coated nanorods. Appearance of intense red emission seems to be very promising since and it could favor more reliable fluorescence sensing in drug delivery fluorescent detection with a minor UV emission.

Abstract: In this work, we report on the synthesis of superparamagnetic iron oxide nanoparticles at room temperature using microemulsion template phase consisting of cyclohexane, water, CTAB as cationic surfactant and butanol as a cosurfactant. Silica surface modification of the as-prepared nanoparticles was performed by adding TEOS directly to the alkaline medium. The structure, morphology, and magnetic properties of the products were characterized by X-ray powder diffraction (XRD), Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), and vibrating sample magnetometer (VSM) at room temperature. The results revealed formation of iron oxide nanoparticles, with an average size of 8.8-12 nm, a superparamagnetism behavior with fast response to applied magnetic fields and zero remanence and coercivity.

Abstract: Semiconductors have been suggested as ideal candidates for many electrical and optical applications and several groups have reported their successful synthesis in recent years. In particular, ZnS that is a direct wide band gap (3.91 eV) semiconductor and an important phosphor host lattice material, can be used in electroluminescent devices (ELD), due to its large band gap, which enables emission of visible light without absorption and efficient electron transport. In this work, we report synthesis and structural characteristics of gold covered core-shell nanometer size of ZnS/SiO₂ thin films as a patterning materials for use as a protective layer in optical phase change discs prepared through a simple sol-gel process. The results obtained by transmission electron microscopy (TEM) images showed that, as prepared core-shell materials were well-aligned nanoprticles grew in the same direction and through X-ray diffraction (XRD) analysis, we found that ZnS/SiO₂ core shell material was composed of crystalline ZnS core covered by an amorphous SiO₂ shell. Photoluminescence (PL) measurements performed on core-shell samples before and after gold coverig samples have provided information regarding stoichiometric vacancies or interstitial impurities and enhenced intensity of the green emission of ZnS nanowires at room temperature due to sheelding with SiO₂.

Abstract: Immobilized enzymes enhance process robustness, allow longer duration of activity of enzymes, and re-use of the same enzymes in multiple cycles. Enzymes can be operated in the liquid form or immobilized on various supports. In this work, we prepared gold nanoparticle core-shell structure by assembling of the gold nanoparticles on the surface of amine-functionalized x-type zeolite and then used them for immobilization of the alkaline protease. Characterization of these assembled systems were carried out by UVvisible, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and energy dispersive analysis of X-ray (EDAX). Biocatalytic activity of the alkaline protease in this bioconjugate system was examined and showed an increase in comparing with the free enzyme in solution.

Abstract: Magnetic iron oxide nanoparticles with proper surface coatings are increasingly being evaluated for clinical applications such as hyperthermia, drug delivery, magnetic resonance imaging, transfection and cell/protein separations. In this work, silica coated iron oxide magnetic nanoparticles, which are very useful for delivering chemotherapeutic drugs, has been prepared by precipitation in an aqueous solution of iron (II) and iron (III) chlorides under basic condition. In this process, polyvinylpyrrolidone (PVP) has been used as a stablizer. Surface modifications of the as-prepared Fe3O4 Nps have been carried out by using tetraethoxysilane (TEOS). Silica coated nanoparticles have been characterized by Fourier transform infrared (FTIR) spectroscopy, Powder X- ray diffraction (XRD), Transmission electron microscopy (TEM) and Infrared (IR) spectroscopy

Abstract: In this paper, we report preparation of hydrophilic hybrid nanocomposite coatings on glass substrates using Zinc acetate solutions based on 3-glycidoxypropyltrimethoxysilane (GPTMS), epoxy resin, aromatic amine (HY850), polyethylene glycol (PEG) and surfactant (polyoxyethylene(4)laurylether) by the sol-gel process. Furthermore, the effects of PEG addition to the precursor solutions on the hydrophilic property and microstructure of the resultant coating film were studied. The hydrophilic behavior study of the synthesized hybrid was performed by adding different amounts of polyethylene glycol precursor to the hybrid solution. Experimental results show that, among different amounts of PEGs, the best results are obtained by addition of PEGs (400) to the hybrid solution which can decrease the water contact angles down to 16 and using surfactant down to 0, and increase the free surface energy. Coated glass exhibits a higher strength than uncoated glass. Attenuated total reflectance infrared spectroscopic (ATR-IR) technique was used to characterize the structure of the hybrid films. The chemical structure of obtained network affects morphology of the coating. The morphology of the hybrid coatings was examined by transmission electron microscopy (TEM). The hybrid systems have a unit form structure and the inorganic phases were in the nanosize scale,