Showing papers by "Sirus Javadpour published in 2013"
TL;DR: In this paper, polyethylene glycol decorated, citric acid capped magnetite nanoparticles (MNPs) with proper physicochemical characteristics including particle size distribution, morphology, magnetic property and stability in a biologic medium were synthesized by a biocompatible chemical co-precipitation of Fe2+ and Fe3+ in an ammonia solution.
76 citations
TL;DR: In this paper, the effect of different quench environments, including water, oil, air, −30 −C ethanol and −195 −C liquid nitrogen, on the final microstructure and wear behavior of the 1.2080 tool steel was investigated.
41 citations
TL;DR: In this article, the evolution of the microstructure and magnetic properties during the milling process were studied by the X-ray diffraction technique, the scanning electron microscope, the transmission electron microscope and the vibrating sample magnetometer.
32 citations
TL;DR: In this article, Al 2 O 3 as a ceramic coating was deposited on the surface of the MCrAly as a ground coat layer on Ni-based super alloy, by cathodic plasma electrolytic deposition (CPED).
Abstract: Inconel alloys (IN738) have found a wide range of applications in industries such as high-temperature resistance materials. Furthermore, different surface treatments and coatings have been developed for improving the properties of Inconel alloys. In this study, Al 2 O 3 as a ceramic coating was deposited on the surface of the MCrAly as a ground coat layer on Ni-based super alloy, by cathodic plasma electrolytic deposition (CPED). The CPED process was carried out in Ethanol solution of Al (NO 3 ) 3 .9H 2 O (18 g/l). Several samples were obtained in different deposition conditions and analyzed using XRD, SEM and EDS. The XRD analysis shows the presence of Al 2 O 3 and Ni 3 Al phases. Based on thermal expansion, this is in agreement with the composition of the MCrAlY used as bond coat. SEM micrograph showed changes in microstructure of specimen by varying the pH of the solution in different PH of solutions.
28 citations
TL;DR: In this article, high energy ball milling of ZnO, NiO and Fe2O3 powder mixtures was used to obtain nanocrystalline Ni0.64Zn0.36Fe2O4 powders.
27 citations
TL;DR: In this article, the effect of the as-quenched vacancies on the formation of nano-and micron-sized carbides during the deep cryogenic heat treatment of 1.2080 tool steel was investigated.
25 citations
TL;DR: A novel hyperthermia material for cancer therapy, cationic albumin-conjugated magnetite nanoparticles (MNPs), which absorb the energy of an alternating magnetic field and convert it into heat by carbodiimide chemistry is developed.
Abstract: We developed a novel hyperthermia material for cancer therapy, cationic albumin-conjugated magnetite nanoparticles (MNPs), which absorb the energy of an alternating magnetic field and convert it into heat. MNPs of about 10 nm were synthesised through co-precipitation, and citric acid was used to stabilise the MNP suspension. Then albumin was cationised by replacing anionic side chain groups with cationic groups. The surface modification of the MNPs was provided by cationic albumin, which was covalently conjugated to carboxylic acid functions located at the distal end of the MNPs’ surface by carbodiimide chemistry. Finally, we obtained stable superparamagnetic suspensions with particle sizes of 140 nm and saturation magnetisation of 67 emu/g, which do not have the disadvantage of eventual desorption of physical attachment. We also analysed the potential of these particles for magnetic fluid hyperthermia by determination of the specific absorption rate at a constant frequency of 215 kHz; the tempera...
23 citations
TL;DR: In this article, the effect of the electric current flow through the deep cryogenically treated samples was investigated via the X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive spectroscope (EDX), hardness test, and pin-on-disk wear testing machine.
22 citations
TL;DR: In this article, the structure and magnetic properties of Ni0.64Zn0.36Fe2O4 powders were characterized and their properties were compared by the glycine-nitrate autocombustion process and the solid state reaction method (SSRM).
Abstract: Ni–Zn ferrite compositions (Ni1−x
Zn
x
Fe2O4) are well known due to their remarkable soft magnetic properties, which potentially have a broad range of applications in many areas. In this study, Ni–Zn ferrite with the chemical formula of Ni0.64Zn0.36Fe2O4 was prepared by the glycine-nitrate autocombustion process (GNP) and solid state reaction method (SSRM). In order to achieve a desirable particle size, the SSRM powders were milled for 3 h at a milling rate of 200 rpm. The structure and magnetic properties of the ferrite powders, which were synthesized by both methods, were characterized and their properties were compared. The results indicate that a significant amount (∼ 90 wt.%) of nanocrystalline Ni0.64Zn0.36Fe2O4 ferrite with the average crystallite size of 47 nm, particle size of 200 nm, saturation magnetization of 73 emu/g and coercivity of 54 Oe has been formed by means of the glycine-nitrate process. The results also show that not only the saturation magnetization of the GNP ferrite powder is relatively similar to that of the milled SSRM powders, but also it is synthesized at a much shorter duration than that of the solid state reaction method.
18 citations
TL;DR: In this article, the effect of attrition milling on the structure and hardness of 1.2080 tool steel during the deep cryogenic heat treatment was investigated via the scanning electron microscope (SEM), X-ray diffraction (XRD), and microhardness and hardness evaluation.
15 citations
TL;DR: In this article, the thermal shock behavior and microstructural investigation of CoNiCrAlYSi coatings applied by Low Vacuum Plasma Spray (LVPS) and High-Velocity Oxy Fuel (HVOF) techniques on the Ni-base superalloy IN738LC were examined.
TL;DR: In this article, the effect of adding stearic acid as a process control agent (PCA) on the particle size, structure and magnetic properties of Fe-45-wt% Ni alloy powders have been studied by X-ray diffraction, scanning electron microscope and vibrating sample magnetometer measurements.
TL;DR: In this article, an efficient carbon monoxide (CO) sensor was developed based on poly(3,4-ethylenedioxy)thiophenepoly(styrenesulfonate) (PEDOT:PSS) modified with a new pyrimidine-fused heterocyclic compound, bis(2hydroxyphenyl)dihydropyrido[2,3-d:6,5-d]dipyrimidine -tetraone (B2HDDT).
Abstract: An efficient carbon monoxide (CO) sensor was developed based on poly(3,4-ethylenedioxy)thiophenepoly(styrenesulfonate) (PEDOT:PSS) modified with a new pyrimidine-fused heterocyclic compound, bis(2hydroxyphenyl)dihydropyrido[2,3-d:6,5-d]dipyrimidine-tetraone (B2HDDT). B2HDDT remains stable in the polymer matrix through interactions with functional groups of the polymer. It created prominent sites that captured CO gas, and the experimental parameters, including the amount of doped B2HDDT in the PEDOT:PSS film, were optimized. The sensor probe was also examined to verify its reliability for detecting CO in the presence of atmospheric gases in a discriminating manner. NMR, AFM, and FT-IR spectra were obtained to evaluate the structure and morphology of the B2HDDT-doped PEDOT:PSS (PEDOT:PSS/ B2HDDT) film. The content of 35 vol % B2HDDT (7.0 mM) in PEDOT:PSS provided the largest response factor (ΔR/Ro) for the CO gas. The sensor response was reproducible, with a relative standard deviation < 5% (n = 5). The detection limit was determined to be 0.44 ± 0.05 vol %.
TL;DR: In this article, the synthesis of aluminum, silicon nitride and carbon powders was investigated by X-ray diffraction and scanning electron microscopy, and it was concluded that the procedure used in this work successfully leads to the product with no need to apply an electric field or utilize a nitrogen atmosphere.
TL;DR: In this article, the evolution of the microstructure and magnetic properties during the milling were studied by X-ray diffraction technique, scanning electron microscopy, transmission electron microscope and vibrating sample magnetometre.
Abstract: In this study, nanocrystalline Ni0·64Zn0·36Fe2O4 powders were prepared using a planetary ball mill. The evolution of the microstructure and magnetic properties during the milling were studied by X-ray diffraction technique, scanning electron microscopy, transmission electron microscopy and vibrating sample magnetometre. It is revealed from the results of the phase analysis that nanocrystalline Ni0·64Zn0·36Fe2O4 ferrite with average crystallite size of 6·18 nm and non-uniform lattice strain of 0·33% has been formed after 60 h of milling time. A progressive increase of saturation magnetisation and a dramatic decrease in coercivity were also observed with increasing milling time.