S.K. Sadrnezhaad
دانشگاه صنعتی شریف
[ 1 ] - سینتیک تشویه پنتا اکسید وانادیم با کربنات سدیم
وانادیم به طور گسترده، ولی به میزان اندک (150 پی پی ام) در پوسته زمین پراکنده است. این فلز در فولاد سازی، صنایع رنگ و تولید کاتالیزور کاربرد دارد. تمایل به بازیافت وانادیم از مواد ثانویه مانند کاتالیزورهای مستعمل با توجه به کاهش منابع طبیعی و افزایش قیمت فلز، در حال افزایش است. در فرایند بازیابی وانادیم، واکنش‌های بسیاری انجام می‌شوند. واکنش تشویه اکسیدوانادیم به دلیل کندی سرعت و بزرگی زمان تکم...
[ 2 ] - خواص ساختاری و فیزیکی پوشش‌های نازک نانوکامپوزیتی دی‌اکسید تیتانیم: نانولوله کربنی سنتز شده به‌روش سل- ژل غوطه‌وری به منظور استفاده در سلول خورشیدی رنگ‌دانه‌ای
TiO2/MWCNT nanocomposite thin films containing different percentages of multi-walled carbon nanotubes were coated on fluorinated tin oxide substrates by sol-gel dip coating method. Results of X-ray diffraction analysis indicated that the crystal structure of the coatings was anatase TiO2. It was also understood that the size of crystallites reduced with CNT but structural properties and equilib...
[ 3 ] - رفتار مکانیکی آلیاژ نیکل - تیتانیم متخلخل ساخته شده به روش سنتز احتراقی حجمی برای استفاده در جراحی استخوان
Mechanical property of porous nickel-titanium alloy produced by volumetric combustion synthesis (VCS) for bone surgery applications is reported in this paper. Stress-strain behavior of the alloy is determined by uniaxial tension test. Superelastic diagram of the porous alloy is compared with that of the solid material cooled from austenite stability temperature. Due to movements of the dislocat...
[ 4 ] - نانومیله‌های نانوبرگ‌دار شده دی‌اکسید تیتانیم دوفازی به‌منظور استفاده در کاربردهای فتوالکتروشیمیایی
Rutile-phase titanium dioxide nanorod arrays were prepared by the hydrothermal method. Then, anatase-phase nanoleaves were successfully synthesized on the nanorod arrays via mild aqueous chemistry. Nanorod arrays scanning electron microscopy revealed that the thin film is uniform and crack free and the average diameter and height of the nanorods are 90 nm and 2 µm, respectively. Furthermo...
[ 5 ] - Nitinol Spinal Vertebrae: A Favorable New Substitute
Scoliosis, kyphosis, and bone fracture are health problems, especially of the elderly throughout the world. The vertebra protects the spinal cord. Any impairment to the vertebra can lead to pain and nervousness. Ni-Ti alloy (Nitinol) helps to resolve the problem by fulfilling such requirements as for strength, durability, resistance to wear, and shockwave damping which is due to the shape memor...
[ 6 ] - Fluoride Precipitation of Cu Over Fe in a Selected pH Window
Fe is an impurity in most leach liquors. Its coexistence with copper in leaching solution of chalcopyrite (CuFeS2) which is the most important mineral of copper creates major extraction problems. Hydrochloric acid dissolves both copper and iron during chloride leaching of this mineral. Separation of Fe from Cu is thus necessary to obtain pure copper. This paper presents a novel metho...
[ 7 ] - Fabrication of Spiral Stent with Superelastic/ Shape Memory Nitinol Alloy for Femoral Vessel
Stent is a metal mesh tube for opening the obstructed vessels of the body. Ni-Ti alloy is a suitable metal for fabrication of stent due to its potential for applying the appropriate stress and strain to the vessel walls. In this study, super-elastic Nitinol wire was used to build stent samples usable to open femoral vessel. Ageing was performed at 500°C for different periods of time to determin...
[ 8 ] - Synthesis and Characterization of Anatase-coated Multiwall Carbon Nanotube for Improvement of Photocatalytic Activity
Sol-gel technique was used to coat multiwall carbon nanotubes (MWCNTs) with anatase titania to increasing the surface area and improve the photocatalytic activity of TiO2. Room temperature ballistic conduct of MWCNT combined with semiconducting behavior of anatase brought about a photocatalytic improvement of ~37 % with respect to the highest methyl orange decolorization flair. For characteriza...
[ 9 ] - EFFECT OF Si ANTIOXIDANT ON THE RATE OF OXIDATION OF CARBON IN MgO- C REFRACTORY
Progressive conversion/shrinking core (PC-SC) models of constant-size cylinders were exploited to interpret the decarburization reactions of MgO-C-Si bricks heated up under blown air. Chemical adsorption/solid (or pore) diffusion mechanisms governed the reaction rate. With 5% silicon, chemical adsorption vanished at 1000 and 1100°C. The oxidation rate lowered then with temperature. This was due...
[ 10 ] - Characterization of Constrained Aged Niti Strips for Using In Artificial Muscle Actuators (Technical Note)
Marvelous bending/straightening effects of two-way shape memory alloy (TWSMA) help their employment in design and manufacturing of new medical appliances. Constrained ageing with bending load scheme can induce two-way shape memory effect (TWSME). Scanning electron microscope (SEM) analysis, electrical resistivity measurement (ERM) and differential scanning calorimetry (DSC) are employed to dete...
[ 11 ] - Extraction of Zn, Mn and Co from Zn-Mn-Co-Cd-Ni containing solution using D2EHPA, CYANEX® 272 and CYANEX® 302
Effects of pH, D2EHPA, Cyanex® 302 and Cyanex® 272 on extractions of zinc, manganese and cobalt from a Zn-Mn-Co-Cd-Ni containing solution was comprehensively investigated at the room temperature. The addition of Cyanex® 302 indicated a left-shifting-effect on the extraction curve of zinc, a right-shifting-effect on the extraction curve of manganese and no effect on the extraction of cobalt. The...
[ 12 ] - Pulse Reverse Electrodeposition of Spherical Ni-MWCNT Composite Skein
Watt’s bath and pulse reverse (PR) electrodeposition is used to produce spherical nickelmultiwall carbon nanotubes (Ni-MWCNT) of 2.00, 0.93, 1.63 and 6.71 μm diameter and a variety ofsize distributions. For 60 cycles, an absolute electrodeposition current of 18 A/dm2 is applied atcurrent ratios of ii = idissolution/ideposition = 0, 0.077, 0.200 and 0.368. A simple exponential equation isfitted ...
[ 13 ] - Thermodynamic Evaluation of Adsorption of Zinc Complex and ZnO Nano-Layer Prepared by TSCD Method Based on Langmuir Adsorption Model
Zinc oxide thin films were deposited on soda-lime glass substrates from an aqueous zinccontaining complex by two-stage chemical deposition (TSCD) method. Longmuir adsorption model showed that the adsorption of atoms on the surface of the substrate was typically physical. The relation between the fractional coverage, θ, with the equilibrium constant of the adsorption reaction was nonlinear indic...
[ 14 ] - Hydrothermal Synthesis of Aligned Hydroxyapatite Nanorods with Ultra-High Crystallinity
Hydroxyapatite nanorods aligned with ultrahigh crystallinity and high-yield were successfully synthesized through a hydrothermal approach. In this experiment, a new composition of cetyltrimethylammonium bromide ((CH3(CH2)15N+(CH3)3Br-) was designated as CTAP)/Ca(NO3)2/(NH4)2HPO4/NaOH and distilled water under hydrothermal condition, to synthesize single crystalHAp nanorods with diameter of 20 ±...
[ 15 ] - Electrochemical Deposition of Flower-Like Nickel Nanostructures on Well-Defined n-Si (111):H
In this paper the electrodeposition of nickel on n-Si(111):H substrate, in the presence of sulphuric acid, was studied. Cyclic voltammetry has been used to characterize the electrochemical behavior of the system. The nickel deposits had a flower-like morphology with the sphericalnanostructure nucleus, distributed uniformly on the surfaces of the prepared n-Si(111) substrate.
[ 16 ] - Formation of Lanthanum Hydroxide Nanostructures: Effect of NaOH and KOH Solvents
Lanthanum hydroxide (La(OH)3) nanostructures, including elliptical nanoparticles, octahedral rods and irregular nanoparticles were prepared chemically in NaOH and KOH solutions with 10 M concentration. The obtained powders were characterized with XRD, SEM, TEM and DTA. Crystallinities, morphologies and thermal behavior of the obtained nanostructure powders were investigated under the influence ...
[ 17 ] - Two-Stage Chemical Deposition of Oxide Films
Two-stage chemical deposition (TSCD) technique is used to produce ZnO, Mn2O3 and NiO films on soda-lime glass (SL-G) from an aqueous solution of zinc, manganese and nickel complex, respectively. The TSCD method enables the deposition of metal oxide thin films with a thickness which can be controlled during the preparation procedure. The ZnO, Mn2O3 and NiO thin films were polycrystalline films w...
[ 18 ] - Particles Size Distribution Effect on 3d Packing of Nanoparticles Into a Bounded Region
In this paper, the effects of two different Particle Size Distributions (PSD) on packingbehavior of ideal rigid spherical nanoparticles using a novel packing model based on parallelalgorithms have been reported. A mersenne twister algorithm was used to generate pseudorandomnumbers for the particles initial coordinates. Also, for this purpose a nanosized tetragonal confinedcontainer with a squar...
[ 19 ] - Leaching Recovery of Zinc, Cobalt and Manganese from Zinc Purification Residue
This paper reports on the recovery of zinc, cobalt and manganese by two-step leaching of zinc-plants purification residue with sulfuric acid. The residue, hot filter press cake (HFC), contains 14 % ZnO, 4.8 % Co3O4 and 22.9 % MnO. Effects of different parameters are determined and used to optimize the process. With acid to hot filter press cake (HFC) stoichiometry of 0.85, acid concentration of...
[ 20 ] - Thermodynamics of Extraction of Zn2+ from Sulfuric Acid Media with a Mixture of Dehpa and Mehpa
Thermodynamics of extraction of Zn2+ from sulfuric acid media contacting to a mixture of DEHPA and MEHPA diluted with 80 wt% aromatic-aliphatic kerosene with a constant DEHPA to MEHPA ratio is investigated at different acidities, concentrations and temperatures. As a result, the extraction reaction is found to be endothermic with a zinc distribution factor that increases with increasing of the ...
[ 21 ] - Software for Kinetic Process Simulation (RESEARCH NOTE)
The relationship between velocity of chemical reactions with activities or concentrations of their reactants, temperature and pressure and the mechanisms through which the reactions proceed are of interest to many scientists and engineers. The purpose of this article is to introduce a computer software that is developed for calculation, classification and collection of such data. The applicatio...
[ 22 ] - Thermodynamics and Kinetics of Vaporization of Pbs From Complex Cu-Fe Mattes
Thermodynamics and kinetics of vaporization of lead sulfide from typical copper-smelting mattes of commercial interest are investigated in the temperature range 1388 K to 1573 K by vapor transport technique and plasma arc spectroscopy. The total mass of the dominant vaporizing species PbS that leaves the matte is described by the Newman's numerical solution to the second Fick's law combined wit...
[ 23 ] - Effect or Inoculation on Microstructure and Properties of Low C-Mn and Low Alloy Steels
Effect of the addition of various inoculants on the morphology and mechanical properties of low C-Mn and low alloy steel samples is studied by thermal and mechanical processing of the samples after solidification. According to the results obtained from metallographic studies with the electron microscope and microanalysis with x-rays, the distribution of inoculating agents in the steel matrix is...
[ 24 ] - Direct Reduced Iron an Advantageous Charge Material for Induction Furnaces
Industrial and experimental induction furnaces are used for melting various types of iron ingots, returned scraps and DRI sponge pellets to produce high purity cast - iron and steel heats. The lowest consumption of electrical energy determined for continuous feeding operation is 0.3 KWH/Kg for the production of cast - iron in a 1.5 - ton industrial furnace and 0.45 KWH/Kg for the production of ...
[ 25 ] - Sulfur Species in Particulates Emitted from Reducing Coal Combustion and Pyrometallurgical Furnaces
The method of X-Ray Photo-electron Spectroscopy is used to determine the chemical state of the sulfur species present in fly-ash samples produced by burning a number of pulverized coal samples under reducing conditions in a continuous combustion furnace. The influence of submicron metallic constituents present in the flue-gases of the pyrometallurical systems on the state of the sulfur species ...
[ 26 ] - مقایسه نانوورقه های کربن نیترید سنتز شده به دو روش حرارتی و اولتراسونیکی-حرارتی (ترکیبی)
در این پژوهش به منظور بررسی تاثیر اولتراسونیک کردن در سنتز کربن نیترید نانوورقه‌ای از پیش‌ماده ملامینی، از دو روش حرارتی و ترکیبی با شرایط و سیکل حرارت‌دهی یکسان استفاده شده است. ابتدا ملامین در مدت 75 دقیقه به 550 درجه سانتی‌گراد رسید و برای مدت 4 ساعت در همین دما باقی ماند تا g-C3N4 بدست آید. در روش حرارتی، g-C3N4 بدست آمده در مدت 100 دقیقه به 500 درجه سانتی‌گراد رسید و برای مدت 3 ساعت در این...
[ 27 ] - Synthesis of the Graphitic Carbon Nitride-hematite Nanocomposite for Using in Cancer Treatment
This article has no abstract.
[ 28 ] - Synthesis of Zinc/Zinc Oxide Nanoparticles by Electric Discharge Method in Distilled-Water and Argon-Gas Environments
Zinc/zinc oxide nanoparticles are used in an increasing number of medical and industrial applications due to their attractive physical, chemical and antibacterial properties. Therefore, achieving a simple and beneficial way to produce them is an important aspect. In this study, zinc/zinc oxide nanopowders were synthesized by fast electric discharges between two electrodes of (a) a spark device ...
نویسندگان همکار
H. Arami 1