Time filter

Source Type

Ahmed A.-F.,National Center for Radiation Research And Technology | Zakaria K.M.,Egyptian Nuclear and Radiological Regulatory Authority
Colloid and Polymer Science | Year: 2014

The surface of poly (ethylene-co-tetrafluoroethylene) (PETFE) strip was grafted by acrylic acid (AAc) and methyl methacrylate (MMA) onto PETFE skeleton to improve the blood compatibility and reduce thrombogenicity for prosthesis. The grafting process was carried out via γ-rays technique as initiator for addition reaction. The optimal conditions were achieved by investigating the effect of different parameters during the grafting process such as exposure to irradiation dose, comonomer concentration, comonomer composition, and solvent. The surface microstructure and composition of copoly (AAc/MMA)-grafted-PETFE surface were characterized by Fourier transform infrared spectroscopy (FTIR), CHNS/O elemental analyzer, scanning electron microscopy (SEM), and electron spectroscopy for chemical analysis (ESCA). Further, heparin was introduced onto the grafted PETFE strip surface. The blood compatibility of modified strip was investigated by the determination of platelet adhesion and thrombus formation. The results indicate that the heparinized copoly (AAc/MMA)-grafted-PETFE sample is a good candidate for manufacturing the prosthetic cardiac valves. © 2014, Springer-Verlag Berlin Heidelberg.

Shaaban N.,Egyptian Nuclear and Radiological Regulatory Authority
International Journal of Signal and Imaging Systems Engineering | Year: 2015

We propose a new signal processing method to improve the energy resolution of superconducting tunnel junction X-ray detectors. An optimum FIR (Finite Impulse Response) filter design tool based on fast Fourier transform was developed using genetic algorithms. The fast Fourier transform is perhaps one of the most used algorithms today in the analysis and manipulation of digital or discrete data. The main feature of this tool is that it needs a minimum number of parameters to specify the FIR filter specifications. This tool was applied successfully on transition edge sensor detector. © Copyright 2015 Inderscience Enterprises Ltd.

Abdellah W.M.,Egyptian Nuclear and Radiological Regulatory Authority | Al-Masri M.S.,Syrian Atomic Energy Commission
Journal of Environmental Radioactivity | Year: 2014

Uncontrolled disposal of oilfield produced water in the surrounding environment could lead to soil contamination by naturally occurring radioactive materials (NORM). Large volumes of soil become highly contaminated with radium isotopes (226Ra and 228Ra). In the present work, laboratory experiments have been conducted to reduce the activity concentration of 226Ra in soil. Two techniques were used, namely mechanical separation and chemical treatment. Screening of contaminated soil using vibratory sieve shaker was performed to evaluate the feasibility of particle size separation. The fractions obtained were ranged from less than 38μm to higher than 300μm. The results show that 226Ra activity concentrations vary widely from fraction to fraction. On the other hand, leaching of 226Ra from soil by aqueous solutions (distilled water, mineral acids, alkaline medias and selective solvents) has been performed. In most cases, relatively low concentrations of radium were transferred to solutions, which indicates that only small portions of radium are present on the surface of soil particles (around 4.6%), while most radium located within soil particles; only concentrated nitric acid was most effective where 50% of 226Ra was removed to aqueous phase. However, mechanical method was found to be easy and effective, taking into account safety procedures to be followed during the implementation of the blending and homogenization. Chemical extraction methods were found to be less effective. The results obtained in this study can be utilized to approach the final option for disposal of NORM contaminated soil in the oilfields. © 2013 Elsevier Ltd.

Akl Z.F.,Egyptian Nuclear and Radiological Regulatory Authority
Journal of Radioanalytical and Nuclear Chemistry | Year: 2015

A sensitive cloud point extraction method was developed for uranium(VI) preconcentration and determination in aqueous solutions. The method is based on uranium(VI) complexation with eriochrome cyanine R and extraction of the complex into the cationic surfactant CTAB at pH 5.5. The optimal extraction and reaction conditions were evaluated and optimized. Under optimum conditions, linearity was obtained for uranium(VI) concentration range of 10–200 ng mL−1 and the limits of detection and quantification were 0.70 and 2.33 ng mL−1 respectively. The interference effect of some anions and cations was evaluated. The method was successfully applied for uranium(VI) spectrophotometric determination in water samples. © 2015 Akadémiai Kiadó, Budapest, Hungary

Gomaa R.I.,Egyptian Nuclear and Radiological Regulatory Authority | Shohdy I.A.,The British University in Egypt | Sharshar K.A.,National Center for Radiation Research And Technology | Al-Kabbani A.S.,Cairo University | Ragai H.F.,Ain Shams University
IEEE Sensors Journal | Year: 2014

Upon tightening new regulations, the demand for using smart wireless sensing for health, safety, and surveillance applications of nuclear installations is growing rapidly. To help with the developments, this paper describes the design of a practical small-scaled wireless sensor network (WSN) that allows a smart real-time monitoring of radiation levels at nuclear facilities. A wireless system compiled with a radiation sensor and associated peripherals been developed and implemented upon ZigBee technology using TI CC2530 chip. The radiation sensor uses a Geiger Muller tube as a reliable detector for the radioactive particulates in the gaseous effluent vented from nuclear facilities. The WSN allows the operators to record and control the radiation levels emitted to the environment and it is supported with a warning system, for the early detection of radiation release. However, building a reliable wireless sensing system with an effective coverage, especially for indoor applications, requires professional planning and proper investigation. In this paper, a procedure to investigate the wireless sensing coverage is reported where a ray-tracing simulator is adopted to enable the wireless node placement prior to the deployment. A real test scenario has been implemented based on the built wireless node to examine network coverage inside a 60-m hallway and results have been compared with simulations showing a 100% packet reception ratio. © 2014 IEEE.

Discover hidden collaborations