International Journal of Nanoparticles (9 papers in press)
- Use of Carbon Nanotubes in Concrete for Structural Health Monitoring- A Review
by Mohamed Elkashef
Abstract: Carbon nanotubes (CNTs) are on the frontline of materials research and innovations worldwide. There is a growing interest in CNTs due to their superior mechanical, electrical and thermal properties. The electrical conductivity of individual CNTs is in the order of 104 107 S/m. The incorporation of CNTs in concrete leads to an increase in the electrical conductivity of the CNT/concrete composite. Recently, the use of CNTs in concrete in structural health monitoring has attracted a lot of attention. CNTs/cement composite have shown piezoresistivity property where the electrical resistance of the composite varies with load. This property offers a practical way to sense load variations by monitoring the electrical resistivity of the structure. This paper will give an overview of the current research efforts in this regard. The review will cover the use of both functionalized and pristine CNTs. An overview of the Chemical vapor deposition (CVD) method which is most commonly used to synthesize CNTs will also be presented.
Keywords: Carbon nanotubes; Nanotechnology; CNT/concrete composites; Pressure-sensitivity; Piezoresistivity; Nanocomposites
- Magnetic iron oxide nanoparticles: preparation and hyperthermia applications
by thanaa Shalaby, Yousef Yousef, Mostafa Mohamed, Hisham Badwy
Abstract: The magnetic hyperthermia is based on localized heating of tumor keeping the healthy cells out of harm. In the process, magnetic hyperthermia involves dispersing magnetic nanoparticles (MNPs) throughout the target tissue and then exposed to ultrasound and/or microwave energy to cause the particles to be heated up to the required temperature of about 45oC. Superparamagnetic nanoparticles were prepared through the co-precipitation method and characterized using TEM, SEM, X-ray diffractometer and Fourier-transform Infrared (FTIR). Magnetic behavior of nanoparticles was studied using Vibrating-Sample Magnetometer (VSM). Through the treatment period, tumor volume was determined every other day. After treatment period, the dielectric properties of the treated tissues were determined. Tumor apoptosis was studied using transmission electron microscope. The results indicate that the magnetic fluid is a suitable mediator for cancer treatment using hyperthermia application with appropriate controlling the heating temperature ranges from 45 to 50oC using microwave and/or ultrasound energy.
Keywords: Superparamagnetic nanoparticles; Magnetic properties; Co-precipitation; Magnetic fluid hyperthermia; Microwave; Ultrasound; Dielectric properties; Apoptosis.
- Copper hexacyanoferrate-graphene nanocomposite: Synthesis, characterization and application for the electrocatalytic oxidation and determination of thiosulfate
by Hossein Heli, R Dehdari Vais, N Sattarahmady
Abstract: Copper hexacyanoferrate-graphene nanocomposite was synthesized by a facile precipitation route. The morphology and structure of the nanocomposite were evaluated by scanning electron microscopy, X-ray diffraction and infrared spectroscopy. A nanocomposite-modified carbon paste electrode was fabricated and its redox behavior was characterized by means of different electrochemical techniques. The diffusion of the counter cation into the nanocomposite and the charge transfer kinetics across the electrode/electrolyte interface were studied by chronocoulometry and cyclic voltammetry. In the Nyquist diagrams, different time constants related to different physical and electrochemical processes appeared. In these diagrams, percolation of electron in the copper hexacyanoferrate nanoparticles appeared at very high frequencies, and exhibited the feature of a diffusion process with a transmissive boundary condition at the interface of nanocomposite/graphite particles. At medium frequencies, the redox reaction of copper hexacyanoferrate was performed. At very low frequencies, the diffusion of counter cation into the copper hexacyanoferrate nanoparticles dominated. The diffusion coefficients of electron and the counter cation and also the charge transfer rate constant within the nanocomposite were obtained using impedance spectroscopy. The modified electrode showed an efficient electrocatalytic activity toward the electrooxidation of thiosulfate.
Keywords: Copper hexacyanoferrate; Graphene; Nanocomposite; Thiosulfate; Electrocatalysis
- Au/Ag Composite Nanorings Based on Galvanic Reaction of the Ag Nanoparticles Induced by Laser Ablation in Water
by Liu guangqiang
Abstract: A simple route is presented to fabricate Au/Ag composite nanorings based on the galvanic reaction of the silver colloidal solution by addition of chloroaurate solution. The silver colloidal solution with near monodispersion in size is firstly prepared by laser ablation of Ag target in pure water and subsequent additional irradiation. It has been found that addition of chloroaurate solution to the Ag colloidal solution can produce the Au/Ag composite nanoparticles, which are the ring-like Ag single crystals embedded with ultrafine Au nanoparticles. Further experiments have revealed that appropriate molar ratio of Au to Ag in the solution and round original Ag nanoparticles are crucial to formation of such composite nanorings. This study provides a simple way to fabricate noble metal nanorings with different sizes. Such composite nanorings have exhibited the surface plasmon resonance properties in near-infrared (NIR) bands, and could thus be used as the NIR-excited surface enhanced Raman scattering (SERS) substrates for detection of trace amount molecules and some other nanophotonic devcies.
Keywords: Au/Ag composite nanorings; galvanic reaction; Ag nanoparticles; laser ablation in water
- Synthesis, Characterization and Photo-Catalytic activity of CeO2/Fe2O3 Nano-composite
by Ahmed Farghali, Shimaa Sayed
Abstract: Preparation of nano-composite mixed oxides has a great current interest because it can improve the behavior of the two metal oxides and enhance formation of new stable compounds which have different chemical and physical properties. Nano-composite CeO2-Fe2O3 samples with different molar ratios of the two oxides have been synthesized by co-precipitation method to study the effect of Fe2O3 doping on the magnetic properties and catalytic activity of CeO2. The prepared nano-sized catalysts are characterized by XRD, TEM and SEM. Magnetic properties are measured to evaluate the proposed nano-composite samples. From magnetic measurements it was established that the saturation magnetization in all doped samples is higher than in pure ceria. A great application of the prepared nano-composites, with a vital role in our daily life, is the purification of the polluted waters from some toxic dyes. Complete photo-catalytic degradation of toxic Bromopyrogallol red dye (BPR) is achieved revealing that all doped samples have higher catalytic activities than those of pure catalysts (CeO2 and Fe2O3).
Keywords: CeO2-Fe2O3; nano-composite; magnetic properties; photo degradation; Bromopyrogallol red.
- Physical, Antimicrobial and Cytotoxic Characterization of LaF3:Eu3+ ion doped Nanocrystals
by Aakriti Tyagi, Shweta Agarwal, Kamla Rawat, Anita Verma Kamra, H B Bohidar, Sarla Puram
Abstract: We report synthesis of surfactant free LaF3: Eu3+ (0%, 5%, 10%, 15%, 20%, 25% and 30% (w/w)) ion doped nanocrystals using a facile hydrothermal method. TEM and SEM pictures revealed formation of spherical nanoparticles in 5% and 10% (w/w) doped samples. Nanocrystals with hexagonal structures having lattice parameters (a=7.126
Keywords: lanthanide nanoparticles, europium doping, cytotoxicity, anti-microbial
- Role of amoxicillin functionalized Fe3O4 on the settling velocity of starch
by Shanmugam Palanikumar, Rajeshwaran Palanichamy, Balakrishnan Meenarathi, Hunghsia Chen, Pinghei Chen, R. Anbarasan
Abstract: Amoxicillin functionalized Ferrite nanoparticle was synthesized by co-precipitation method under nitrogen atmosphere. Thus obtained black colored product was characterized by fourier transform infrared (FTIR) spectroscopy, UV-visible spectroscopy, X-ray diffraction (XRD), particle size analysis (PSA), scanning electron microscopy (SEM), field emission scanning electron microscopy (FESEM) and vibrating sample measurement (VSM) techniques. The sedimentation velocity of starch in the presence of Amoxicillin functionalized Ferrite was carried out at three different pH values 2.5, 7.1 and 12.0. The influence of Amoxicillin functionalized Ferrite on the sedimentation velocity of starch was evaluated with the help of FTIR, SEM, VSM, UV-visible, Fluorescence spectroscopy. We noted an important observation that Starch-Fe3O4-Amoxicillin system exhibited the lowest VSM value than the Fe3O4-Amoxicillin system.
Keywords: functionalization; ferrite; starch; amoxicillin; sedimentation.
- Non-Darcy Double Diffusive Mixed Convection for Nanofluid with Soret and Dufour Effects in a Lid-Driven cavity
by Rajarathinam Muthu
Abstract: Unsteady laminar double diffusive mixed convection in a two sided lid driven cavity filled by Cu-water nanofluid with Soret and Dufour effects have been investigated
numerically using the Darcy Brinkman Forchheimer model. Constant temperature and
concentrations are imposed at the vertical walls while the horizontal walls are perfectly insulated. The finite volume method over SIMPLE algorithm is used to solve the non-dimensional governing equations. The results are presented interms of streamlines, isotherms, isoconcentrations and heatline trajectories as well as the mid-height velocity profiles, average Nusselt number and Sherwood number graphs.
Keywords: double diffusive convection; porous medium; nanofluid; lid-driven cavity; Soret and Dufour effects.
- Electrothermo convection in a horizontal layer of rotating nanofluid
by Ramesh Chand
Abstract: Thermal instability in a horizontal layer of nanofluid with vertical AC electric field in the presence of rotation is investigated. The flux of volume fraction of a nanoparticle is taken to be zero on the isothermal boundaries and the eigenvalue problem is solved using the Galerkin method. The model used for nanofluid incorporates the effect of Brownian diffusion, thermophoresis and electrophoresis. Linear stability theory based upon the normal mode technique is employed to find expressions for Rayleigh number for stationary and oscillatory convection. The influence of rotation (Taylor number), Lewis number, modified diffusivity ratio, concentration Rayleigh number, AC electric Rayleigh number on the stationary convection have been investigated both analytically and graphically. The necessary condition for the occurrence oscillatory convection has also been obtained.
Keywords: Taylor number; Lewis number; AC electric field; Brownian motion; Prandtl number