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کاربرد نوع شرط:
- جایگاه : پژوهشی
- مجله: Journal of Nanoanalysis
- نوع مقاله: Journal Article
- کلمات کلیدی: Nanocomposite,superabsorbent,chemical cross-linking method,Structural and surface properties,Water absorption and retention
- چکیده:
- چکیده انگلیسی: In this paper, microstructure and swelling behavior of five superabsorbent hydrogels have been investigated. These samples were prepared by dispersing watermelon shell powder (WSP) and cucumber shell powder (CSP), mixture bentonite and WSP, mixture bentonite and CSP, zeolite (Z) bentonite (B), into poly(acrylamide-co-acrylic acid) (P) backbone in an aqueous medium. The nanocomposites have been synthesized through chemical cross-linking by polymerization technique using N,N-methylenebis acrylamide as a cross-linker and potassium persulfate as an initiator in simple aqueous environmental conditions. The nanocomposite hydrogels named as P-WSP-CSP، P-WSP-B، P-CSP-B، P-Z، P-B, respectively. These superabsorbent nanocomposites were characterized by X-ray diffraction, Fourier transforms infrared and field emission-scanning electron microscope measurements. The water absorption and desorption of the superabsorbent nanocomposites have also been studied. Our findings show that very high water absorption and lower drying rate of P-CSP-B are attributed to higher porous surfaces observed in FE-SEM images. The results show the superabsorbent hydrogels based on CSP represent very high water absorbency capacity and water retention ability that make them suitable for technology applications.
- انتشار مقاله: 27-07-1397
- نویسندگان: Sasan Ganjehie,Ahmad Gholizadeh,Seyed Ahmad Ketabi
- مشاهده
- جایگاه : پژوهشی
- مجله: Journal of Nanoanalysis
- نوع مقاله: Journal Article
- کلمات کلیدی: Mechanical properties,Ferrites,IR spectroscopy,Citrate method,X-ray diffraction method
- چکیده:
- چکیده انگلیسی: In this work, the structural and elastic moduli properties of ZnFe2O4, Zn0.5Cu0.5Fe2O4, and Ni0.
3Cu0.2Zn0.5Fe2O4 ferrites prepared by the citrate method have been investigated. The structural
characterization of the samples is evidence for a cubic structure with Fd-3m space group. The
Halder-Wagner analysis was used to study crystallite sizes and lattice strain and also stress
and energy density. The cation distribution for each composition has been suggested. The
experimental and theoretical lattice constants were found to be in good agreement with each
other confirming the agreeability of the suggested cation distribution. The force constants
for tetrahedral and octahedral sites have been determined by infrared spectral analysis. The
increase in force constants of ZnFe2O4 nanoparticles compared to other samples suggests the
elastic properties of this sample is better than the other samples. The values of Young’s modulus,
rigidity modulus, bulk modulus, Debye temperature have been determined. In addition,
using the values of the compliance sij obtained from elastic stiffness constants, the values of
Young’s modulus and Poisson’s ratio along the oriented direction have been calculated for the
samples. Consequently, we can conclude the ZnFe2O4 nanoparticles could be more useful in
industrial applications because of their elastic properties compared to other samples.- انتشار مقاله: 31-04-1396
- نویسندگان: Ahmad Gholizadeh,Ahmad Gholizadeh,Ahmad Gholizadeh,Ahmad Gholizadeh
- مشاهده
- جایگاه : پژوهشی
- مجله: Journal of Nanoanalysis
- نوع مقاله: Journal Article
- کلمات کلیدی: Nanoparticles,Structural Properties,Photo-degradation,Cobaltite Perovskite,UV-Visible
- چکیده:
- چکیده انگلیسی: In this paper, La0.55Ca0.45A0.5Co0.5O3(A=Mg, Mn) nanoparticles were synthesized by citrate
method. The samples were characterized using the techniques of using X-ray diffraction
(XRD), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) and UVVis
spectroscopy. The structure was analyzed by Rietveld fitting of the XRD pattern by using
X’Pert package and Fullprof program, these shows that the samples have perovskite structure.
The calculated values of crystallite size, particle size and band gap energy of La0.55Ca0.45Mg0.
5Co0.5O3 are much less than La0.55Ca0.45Mg0.5Co0.5O3. The effects of three operational parameters
including irradiation time, pH, and the catalyst amount on the photocatalytic activity of
the product on the degradation of methyl blue (MB) under solar condition were studied. The
photocatalytic degradation efficiency of MB solution over La0.55Ca0.45Mn0.5Co0.5O3 nanoparticles
is higher than that over La0.55Ca0.45Mg0.5Co0.5O3 nanoparticles. 96 % degradation is obtained
in an aqueous solution at pH=2.33 and containing 30 mg La0.55Ca0.45Mg0.5Co0.5O3 catalyst
after 30 minutes.- انتشار مقاله: 05-03-1397
- نویسندگان: Hamid Yousefi,Ahmad Gholizadeh,Zahra Mirbeig Sabzevari,Azim Malekzadeh
- مشاهده
- جایگاه : پژوهشی
- مجله: Journal of Nanoanalysis
- نوع مقاله: Journal Article
- کلمات کلیدی: Catalytic activity,Hydrothermal Method,Structural study,CuBi2O4
- چکیده:
- چکیده انگلیسی: In the present work CuBi2O4 nano-spinel has been synthesized via mild hydrothermal method
at 180°C for 10 h. The synthesized nanomaterials were characterized by several techniques
to emphasis the structure and properties of produced materials. The crystal structure was
investigated by X-ray powder diffraction method and the values of the refined unit cell volume
and the structure properties were studied by using the Rietveld analysis is done using Fullprof
program. The results shew the formation of tetrahedral structure with space group P4/
ncc for this sample. Also, the morphologies of the synthesized materials were figured out
by field emission scanning electron microscope (FE-SEM). According to the FESEM images,
several nano cubic form of particles grew on micro spherical particles. As well, the catalytic
performance of obtained CuBi2O4 was studied in Biginelli reaction. The reaction conditions of
this study optimized by experimental design method. This experiment stablished high catalytic
performance of copper bismuth oxide in compare with some other metal oxide catalysts. Also,
the results shew this product is reusable homogenous catalyst.- انتشار مقاله: 28-01-1396
- نویسندگان: Fatemeh Soleimani,Mehdi Salehi,Ahmad Gholizadeh
- مشاهده
- جایگاه : پژوهشی
- مجله: Journal of Nanostructures
- نوع مقاله: Journal Article
- کلمات کلیدی: Nanocomposite,Flame retardant,Cubic like,Flake- Like
- چکیده:
- چکیده انگلیسی: In this study, Flake-like magnesium hydroxide (Mg(OH)2) and cubic-like aluminum hydroxide (Al(OH)3) nanostructures were synthesized via a simple co-precipitation method at relatively low temperature. Chemical properties and surface morphology of the magnesium hydroxide and aluminum hydroxide were characterized by X-ray diffraction analysis (XRD), scanning electron microscopy image (SEM), transmission electron microscopy image (TEM), differential scanning calorimetery analysis (DSC) and thermo gravimetric analysis (TGA). Magnesium hydroxide and cubic-like aluminum hydroxide were then added to PVC, Graphite and PMMA polymers. The effect of cooperation between magnesium hydroxide and cubic-like aluminum hydroxide nanostructures on the fire retardant of the polymeric matrixes has been investigated. The results show that the thermal decomposition of the nanocomposites shifts towards higher temperature in the presence of the magnesium hydroxide and cubic-like aluminum hydroxide. As well as, the enhancement of fire retardant of nanocomposites is due to endothermically decomposition of these nanostructures and releases of water and dilutes combustible gases.
- انتشار مقاله: 29-03-1396
- نویسندگان: Ahmad Gholizadeh,Saeid Jamehbozorgi,Mohammad Yousefi,Ali Niazi
- مشاهده
- جایگاه : پژوهشی
- مجله: Journal of Communication Engineering
- نوع مقاله: Journal Article
- کلمات کلیدی: Cognitive Radio,Blind estimation,convolutional code,non-catastrophic encoder,minimal-basic encoder
- چکیده:
- چکیده انگلیسی: This paper concerns to blind identification of a convolutional code with desired rate in a noiseless transmission scenario. To the best of our knowledge, blind estimation of convolutional code based on only the received bitstream doesn’t lead to a unique solution. Hence, without loss of generality, we will assume that the transmitter employs a non-catastrophic encoder. Moreover, we consider a complete synchronous scenario in which one can extract separate codewords from received sequence. This assumption is valid in many practical communication systems because, the frame preambles allow us to identify the beginning of each codewords.
In this paper, we examine the blind identification problem for rate1/n and rate k/n convolutional codes, respectively. For rate 1/n, we propose an iterative method that uses three steps in each iteration to test the validity of a possible value of n. We show that this method can identify the parameters of a rate 1/n convolutional code from only two different noiseless received codewords. Afterwards, we generalize this method for a rate k/n convolutional code in which each iteration is composed of seven successive steps. We show that this method requires at least k+1 different codewords to identify all parameters of a rate k/n code.- انتشار مقاله: 12-10-1395
- نویسندگان: Hossein Khaleghi Bizaki,Ahmad Gholizadeh Soteh
- مشاهده
- جایگاه : پژوهشی
- مجله: Iranian Journal of Chemistry and Chemical Engineering
- نوع مقاله: Journal Article
- کلمات کلیدی: Graphene Oxide,Core-shell structure,Magnetic materials,Degradation of methyl blue and methyl orange
- چکیده:
- چکیده انگلیسی: In this paper, structural, magnetic, optical, and photocatalytic properties of core-shell structure Fe3O4@GO nanoparticles have been compared with Fe3O4 nanoparticles in the degradation of methyl blue and methyl orange. For this purpose, GO nanosheets were wrapped around the APTMS-Fe3O4 nanoparticles and then characterized using X-ray Diffraction, field emission scanning electron microscopy, transmission electron microscopy, vibrating sample magnetometer, UV-visible, and Fourier transform infrared spectroscopy. The results show the core-shell nanostructured Fe3O4@GO is formed. As an application for the synthesized structure, degradation of methyl blue and methyl orange as heavy-mass organic pollutants has been measured. While the saturation magnetization of Fe3O4@GO is lower than Fe3O4, but shows better efficiency in the degradation of methyl blue and methyl orange. The obtained catalysts can be quickly separated from the solution under an external magnetic field because of their considerable Ms values, which will be beneficial for their reuse and boosting the overall water treatment efficiency in practical applications.
- انتشار مقاله: 27-05-1397
- نویسندگان: Amir Abharya,Ahmad Gholizadeh
- مشاهده
- جایگاه : پژوهشی
- مجله: Iranian Journal of Chemistry and Chemical Engineering
- نوع مقاله: Journal Article
- کلمات کلیدی: Photocatalytic activity,Malachite Green,Solid-state,Ni0.5Cu0.5Cr2O4
- چکیده:
- چکیده انگلیسی: In this research, pure-phased Ni0.5Cu0.5Cr2O4 synthesis via solid-state method successfully. In the other part, the photocatalytic activity of synthesized Ni0.5Cu0.5Cr2O4 was investigated in various aspects by using Malachite green as a pollutant and compared with the number of previous photocatalysts. The Photocatalysis process is a promising technique for solving many current environmental and energy issues. The environmental pollutant, especially water contaminates, can influence human health, animals, and the ecosystem. Dye as one of the most important pollutants has investigated in this study. In this study, purification and crystal structure of material have been determined by X-Ray powder Diffraction (XRD) method. The results showed that the synthesized Ni0.5Cu0.5Cr2O4 was crystallized in tetragonal structure with space group I 41/AMD. The morphology of obtained materials was modified by Field Emission Scanning Electron Microscope (FESEM). Also, the material was characterized by Fourier-Transform InfraRed (FT-IR) spectroscopy and Thermo Gravimetric Analysis (TGA).
- انتشار مقاله: 28-11-1396
- نویسندگان: Fatemeh Soleimani,Mehdi Salehi,Ahmad Gholizadeh
- مشاهده
- جایگاه : پژوهشی
- مجله: International Journal of Nano Dimension
- نوع مقاله: Journal Article
- کلمات کلیدی: Photocatalytic activity,Malachite Green,Hydrothermal Method,CuCr2O4,Mn0.5Cu0.5Cr2O4
- چکیده:
- چکیده انگلیسی: In this study phase- pure new spinel structure, Mn0.5Cu0.5Cr2O4 was prepared by hydrothermal method successfully and the degradation of Malachite green as an organic pollutant was investigated and compared with CuCr2O4. Purification of obtained nanoparticles was measured by using X-ray diffraction method (XRD) in which crystal structure and the structural properties were studied by using X’Pert package and Fullprof program. Also, the morphology of obtained materials was modified by field-effect scanning electron microscopy (FESEM). These materials were characterized by Fourier-transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA), respectively. UV-vis diffuse reflectance analysis was done for determination of band gape which evaluated 1.37eV.The photocatalytic application of synthesized materials was evaluated by the degradation of malachite green (MG) in the presence of H2O2 that were assessed by UV–vis spectroscopy analysis. The comparison study of photocatalytic result reviled that Mn0.5Cu0.5Cr2O4 has higheractivity than CuCr2O4.
- انتشار مقاله: 03-10-1397
- نویسندگان: Fatemeh Soleimani,Mahdi Salehi,Ahmad Gholizadeh
- مشاهده