Study, design and manufacture eddy current probes for industry applications

This study is based on the studying, designing and manufacturing of eddy current probes for industry applications. The main tasks of this study include: + Describes the overview and classification of eddy current probes (which can be classified into three categories based on the mode of operation: absolute eddy current probe, differential eddy current probe and reflect eddy current probe). + Describes the three methods of probe designing and manufacturing (including experimental, analytical and numerical designs). + Describes the designing and manufacturing of eddy current probes for industry applications, which based on experimental and analytical methods. Based on this study, we have successfully manufactured some current probes (including absolute eddy current probe, differential eddy current probe and reflect eddy current probe) for surface and tube inspections.

Study on the synthesis of antibacterial plastic by using silver nanoparticles doped in zeolite framework

Silver nanoparticles (AgNPs) doped in the zeolite framework (AgNPs/Z) were successfully synthesized by γ-irradiation in ethanol solution of silver ion-zeolite (Ag+/Z) prepared by ion exchange reaction between silver nitrate (AgNO3) and zeolite 4A. The effects of the Ag+ concentration and irradiation dose on the formation of AgNPs/Z were also investigated. AgNPs/Z with the silver content of about 10,000 ppm and the average particle size of AgNPs of about 27 nm was characterized by ultraviolet-visible spectroscopy, powder X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM). Firstly, AgNPs/Z was added into PP resins for creation of PP-AgNPs/Z masterbatch (Ag content of ~10.000 ppm) and then PP-AgNPs/Z plastics were preapared by mixing masterbatch with PP resins. The antibacterial activity of the PP-AgNPs/Z plastics was investigated against Gram-negative bacteria Escherichia coli (E. coli). The results showed that PP-AgNPs/Z plastic contained 100 ppm of Ag possessed a high antibacterial property, namely the bactericidal effect was more than 96 % on the platic surface. In conclusion, possessing many advantages such as: vigorously antibacterial effect and good dispersion in plastic matrix, AgNPs/Z is promising to be applied as bactericidal agent for plastic industry.

Immobilizing Bacillus subtilis on the carrier of poly (acrylic acid)/sodium bentonite for treating sludge from Pangasius fish ponds

Sodium bentonite (NaBent) was modified by poly(acrylic acid) (PAAc) to prepare the carriers for immobilization of Bacillus subtilis. Different mixtures of NaBent/AAc were regularly dispersed in distilled water and irradiated under gamma rays at an absorbed dose of 6.5 kGy with dose rate of 0.85 kGy/hr in air for polymerization of acrylic acid and formation of poly(acrylic acid)/sodium bentonite (PAAc–NaBent). The reaction yield was determined with the initial concentration of acrylic acid (AAc). The functional group properties of the resulting PAAc–NaBent were analyzed by Fourier Transform Infrared spectra (FTIR). Bacillus subtilis cells were immobilized on both NaBent and PAAc–NaBent as carriers by adsorption method for treating the sludge contaminated by fish feces and residual feed from the Pangasius farming ponds. The results showed that immobilization capacity of Bacillus subtilis on the PAAc–NaBent was better than that on non-modified NaBent. Analysis of BOD for the farming pond water containing Bacillus subtilis and the bacteria immobilized carriers with time revealed the lower BOD values obtained with the samples containing PAAc–NaBent, suggested that degradation of organic pollutants by Bacillus subtilis immobilized on the PAAc–NaBent was faster than that by free bacteria.

Electron-beam irradiation as a quarantine treatment against red mite on exported cut flower of Chrysanthemum

Utilization of phytosanitary irradiation as a potential treatment to disinfest agricultural commodities in trade has expanded rapidly in the recent years. In this study, red mites (Tetranychus sp) isolated from cut Chrysanthemums were treated by electron beam irradiation at doses of 100, 200, 300 and 400 Gy. After irradiation, they were kept at room temperature to determine the effects of electron beam irradiation on red mite at different developmental stages (eggs, nymphs and adults) and the reproduction of female adults. The results showed that the pattern of tolerance to irradiation in red mite was eggs < 2nd instars < adults, in which the adults were the most tolerance stage. The number of eggs laid by the irradiated female mites and the hatching rate significantly decreased when the irradiation dose increased. The hatching rate of eggs at 300 Gy was 4.25% and no larvae F1 survived during observation time. It could be concluded that 300 Gy is the effective quarantine dose for red mite infesting on cut chrysanthemums.

Equipment for measuring the characteristics of X-ray

X-ray measurement equipment is designed which utilizes a pair of photodiode detectors. The equipment is designed which utilizes a pair of photodiode detectors units which receive X-rays through filters with different attenuation coefficients for X-rays. The photodiode detector units preferably includes two pairs of photodiode detectors arranged symmetrically in four quadrants with the diodes in each detector unit in diagonally opposite quadrants. The outputs of the detector units are passed to variable gain amplifiers, gains of which are adjusted to bring the output voltages within a desired range, and the outputs of the amplifiers are integrated by integrators. After a selected period of time, the integration is stopped and the output voltages of the integrators are held and transmitted to an analog-to-digital converter. The ratio of the two output signals from a pair of photodiode detectors represents the kVp value of the X-ray machine and another pair of photodiode detectors used to measure the relative current in milliamps (mA) and exposure time of the x-ray unit.In this study, the equipment have been made for measuring the characteristics of X-Ray with an accuracy of kVp (kV), I (mA) is 5% and the 2% T.

Positron annihilation in mordenite zeolite

The theoretical study of the positron annihilation in complex material such as zeolite is greatly significant to support and increase the accuracy analysis of the material structure from the experimental data of the positron annihilation. The mordenite zeolite is a big and complicated structure consisting of channels and cavities. The analysis of the mordenite structure is studied by the PALS so depending on the selection of the positron lifetime components of the positron annihilation spectra fitting methods. Therefore, these positron life times in on TO4, Na, Ca, K, Fe, H2O and the rings which form the channels and cavities are sophisticatedly studied by the DFT calculation using Ab-initio. The mordenite and modified mordenite zeolite structures are precisely analyzed, and the physical behaviors of the positron in these are more understood by these theoretical results.

Establishment of neutron dose calibration fields based on a ²⁵²Cf source by Monte-Carlo method

This paper presents calculation results based on Monte-Carlo method to select an appropriate neutron moderator and design four configurations for a 252Cf irradiation system. These configurations provide six neutron spectra with the various average energies (1.04 MeV, 1.38 MeV, 1.69 MeV, 2.05 MeV, 2.46 MeV and 2.93 MeV) suitable for the calibration of neutron survey meters and personal dosimeters.

Status on development and verification of reactivity initiated accident analysis code for PWR (NODAL3)

A coupled neutronics thermal-hydraulics code NODAL3 has been developed based on the nodal few-group neutron diffusion theory in 3-dimensional Cartesian geometry for a typical pressurized water reactor (PWR) static and transient analyses, especially for reactivity initiated accidents (RIA).The spatial variables are treated by using a polynomial nodal method (PNM) while for the neutron dynamic solver the adiabatic and improved quasi-static methods are adopted. A simple single channel thermal-hydraulics module and its steam table is implemented into the code. Verification works on static and transient benchmarks are being conducted to assess the accuracy of the code. For the static benchmark verification, the IAEA-2D, IAEA-3D, BIBLIS and KOEBERG light water reactor (LWR) benchmark problems were selected, while for the transient benchmark verification, the OECD NEACRP 3-D LWR Core Transient Benchmark and NEA-NSC 3-D/1-D PWR Core Transient Benchmark (Uncontrolled Withdrawal of Control Rods at Zero Power). Excellent agreement of the NODAL3 results with the reference solutions and other validated nodal codes was confirmed

Synthesis of Ag nano/TiO₂ material by gamma Co-60 ray irradiation method for dye-sensitized solar cell application

Silver nano deposited on TiO2 nano (Ag nano/TiO2) materials with different initial Ag+ content (0.1-0.75%, w/w) were synthesized by Co-60 gamma irradiation and used as photoanode of dye-sensitized solar cells. The characteristics of Ag nano/TiO2 were determined by X-ray diffraction (XRD), transmission electron microscope (TEM) and UV-visible spectroscopy (UV-Vis). Bandgap energy values of Ag nano/TiO2 materials were also determined. Ag nano/TiO2 has improved efficiency of solar-to-electrical energy conversion of solar cells. The efficiency of solar cell assembled with Ag nano 0.75%/TiO2 was of 4.71% which increased about 25.6% compared with that of the cell based on TiO2 (3.75%). Preparation of Ag nano/TiO2 material by gamma irradiation is promising method that may be applied on large scale for production of dye-sensitized solar cells and for other applications as well.

Coulped neutronics/thermal-hydraulics calculation of VVER-1000 fuel assembly

This paper presents a computational scheme using MCNP5 and COBRA-EN for coupling neutronics/thermal hydraulics calculation of a VVER-1000 fuel assembly. A master program was written using the PERL script language to build the corresponding inputs for the MCNP5 and COBRA-EN calculations and to manage the coupling scheme. The hexagonal coolant channels have been used in the thermal hydraulics model using CORBRA-EN to simplify the coupling scheme. The results of two successive iterations were compared with an assigned convergence criterion and the loop calculation can be broken when the convergence criterion is satisfied. Numerical calculation has been performed based on a UO2fuel assembly of the VVER-1000 reactor.