Effect of apple cider vinegar agent on the microstructure,phase evolution,and magnetic properties of CoFe2O4 magnetic nanoparticles

In the present study, spinel structure CoFe₂O₄ nanoparticles were successfully synthesized by the sol-gel auto-combustion technique. The effect of apple cider vinegar (ACV) addition as an organic biocompatible agent on the size, morphology, and magnetic properties of CoFe₂O₄ nanoparticles was investigated in detail. The phase evolution, particle size, and lattice parameter changes of the synthesized phase have been estimated by using Rietveld structure refinement analysis of X-ray powder diffraction data. Also, Fourier transform infrared spectra (FT-IR) of the samples verified the presence of two expected bands correspond to tetrahedral and octahedral metal-oxygen complexes within the spinel structure. Furthermore, microstructural observations revealed that ultrafine particles have a semi-spherical morphology. It was shown that the particles size decreased from ~45 to ~17 nm with an increase in the amount of ACV. Magnetic properties were carried out by vibrating sample magnetometer (VSM) at room temperature. Both the saturation magnetization (M_s) and coercivity (H_c) were found to be significantly dependent on the crystallite size and the amount of ACV.     

Modified Mechanical Coating Technique for the Preparation of Nanohydroxyapatite Coated Ti–6Al–4V Dental Implants

Protection of Metals and Physical Chemistry of Surfaces - To improve the mechanical and biological properties and also to increase the lifetime and performance of Ti–6Al–4V dental...     

Magnetic behavior of nickel–bismuth ferrite synthesized by a combined sol–gel/thermal method

The bulk NiFe_2?xBi_xO₄ ferrites with various Bi³⁺ concentration (x=0, 0.1, 0.15) were synthesized via sol–gel procedure, starting from nickel, bismuth and iron nitrate powders, followed by the conventional thermal treatment. The structural and magnetic properties of the as-prepared ferrites were studied by means of X-ray diffraction, alternating gradient force magnetometry and Faraday balance. The anisotropy constant was determined by the law of approach to saturation (LAS) model. An increasing Bi³⁺ concentration in NiFe_2?xBi_xO₄ leads to a decrease in the saturation magnetization, Néel temperature and the anisotropy constant of the material.     

A novel modified lattice Boltzmann method for simulation of gas flows in wide range of Knudsen number

To cover a wide range of the flow regimes, a new relaxation time formulation by considering the rarefaction effect and the effective dynamic viscosity has been obtained. By using the modified lattice Boltzmann method (LBM), pressure driven flow through micro and nano channels has been modeled for wide range of Knudsen number, Kn, covering the slip, transition and to some extent the free molecular regimes. The results agree very well with existing empirical and numerical data. The velocity profile was predicted as well as the volumetric flow rate and for the first time, the well known Knudsen minimum effect has been captured about Kn = 1.     

Effect of Polyvinyl Alcohol Modified Silica Particles on the Physical and Gas Separation Properties of the Polyurethane Mixed Matrix Membranes

Silicon - Silicon based particles were prepared using tetraethoxysilane (TEOS) as a silica monomer, and low concentration of polyethylene oxide-polypropylene oxide block copolymer (pluronic) with...     

Effects of Fe2O3 and Al2O3 nanoparticle-diesel fuel blends on the combustion,performance and emission characteristics of a diesel engine

Clean Technologies and Environmental Policy - This research investigates the effects of the addition of Fe2O3 and Al2O3 nanoparticles (30, 60 and 90 ppm) and Fe2O3–Al2O3 hybrid...     

Investigating the effect of basalt fiber additive on the performance of clay barriers for radioactive waste disposals

Bulletin of Engineering Geology and the Environment - Radioactive materials are widely used in mining, manufacturing, medicine, and agricultural processes. The waste products from these materials...     

Numerical study and sensitivity analysis on convective heat transfer enhancement in a heat pipe partially filled with porous material using LTE and LTNE methods

An improved design for convective heat transfer in a heat pipe partially filled with porous medium is presented. In the present study, porous media is used to increase heat transfer in laminar flow inside the tube with a constant heat flux boundary condition. The porous segments are set in different positions in the tube, while the ratio of porous volume to total volume of tube is considered to be constant. A performance evaluation criteria (PEC), which takes account of both heat transfer and pumping power, is defined to find the enhanced mode of porous media arrangement. According to the current results, PEC increases with the number of porous segments. Moreover, the sequence of unequal segments arrangement within the tube is from the largest to the smallest part for a higher PEC. Effects of parameters including porosity, Darcy number, and ratio of effective coefficient of thermal conductivity to coefficient of thermal conductivity of fluid (TKR) are investigated for sensitivity analysis. Simulations are conducted using the local thermal equilibrium method. In addition, the local thermal nonequilibrium is also used for comparison. For TKR numbers less than 10, these models show the same results with negligible differences except for TKR more than 10.     

Effect of electroosmotic flow of aqueous suspension of nanosilica on the properties of carbonated concrete

The paper investigates the possibility to use electroosmosis to transport nanosilica (NS) particles inside carbonated concrete, in order to exert a filler effect and enhance its durability performance. This method aims to extending possible beneficial effects of NS to existing reinforced concrete structures, where the presence of a carbonated layer of concrete is very likely. Injection tests were performed with electrochemical cells on carbonated concrete discs with water/cement (w/c) ratios of 0.50, 0.55 and 0.65, using a NS aqueous suspension at the anode. The results indicated that a flow did occur through the concrete disc and it was directed from the anode towards the cathode. A linear relationship between flux and applied voltage gradient was obtained, which is typical of electroosmotic phenomena. The bulk properties of concrete, such as density, water absorption and sorptivity, were not affected by the injection tests, whilst electrical resistivity increased indicating a mild ‘sealing’ effect on the surface. Also microstructural analyses highlighted the local presence of NS that decreased the local porosity close to the surface.