PL
 |
EN
Preferencje help
Polish version English version Język
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 11

Liczba wyników na stronie
first rewind previous Strona / 1 next fast forward last
Wyniki wyszukiwania
help Sortuj według:

help Ogranicz wyniki do:
first rewind previous Strona / 1 next fast forward last
1
Content available Stability study of free radicals in 10 MeV electron beam irradiated quartz as an EPR dosimetry method
Ziaie F., Mohammadzadeh A., Modarresi M.
Nukleonika
|
2009
|
Vol. 54, No. 4
251-254
EN
In this work the stability of free radicals induced by a 10 MeV electron beam in quartz samples was studied. The investigations have been done for different doses and different dose rates. For this reason, quartz samples in powder form were irradiated at different dose rates, i.e. 100, 260 and 630 kGy/min for absorbed dose range of similar to 5–80 kGy using the 10 MeV electron beam radiation. The dose values were validated using a polystyrene calorimeter system as a reference standard dosimetry system. The EPR optimum system parameters were defined and EPR responses at room temperature in air were measured and compared. The EPR signal, which is due to the free radicals induced by electron beam, was also investigated at different time intervals to check its stability. The main objective of this work was to study the feasibility of using quartz as a dosimeter. Thus, the variation of EPR signal intensities with the absorbed dose values were evaluated and plotted in a graph. The results show that the variation of dose rate, do not affect considerably the EPR response.
2
Content available Investigation on polycarbonate nanomembrane production based on alpha particles irradiation
Ziaie F., Shadman M., Yeganegi S., Mollaie A., Majdabadi A.
Nukleonika
|
2009
|
Vol. 54, No. 3
157-161
EN
Track-etched membranes were prepared in the Dosimetry Laboratory of Agricultural, Medical and Industrial Research School by exposing polycarbonate (PC) films with a thickness of about 20 μm to alpha particles emitted from 241Am followed by chemical etching in sodium hydroxide (NaOH) at different temperatures and solution concentrations. The PC films were prepared using the method of chemical solving, forming and drying in a vacuum oven. The etching rate of PC was related to the concentration of etching solution, etching temperature and time. Therefore, a series of track-etched membranes were produced using different etching parameters. The relation between the etching rate and the etching parameters were established from experimental data and can be used to control the average pore sizes of the PC track-etched membrane. The pore sizes and their structures were studied by an optical microscope (OM) and a scanning electron microscope (SEM) and the obtained results indicated that the pores across the PC films are cylindrically shaped.
3
Content available Bone powder as EPR dosimetry system for electron and gamma radiation
Ziaie F., Hajiloo N., Fathollahi H., Mehtieva S. I.
Nukleonika
|
2009
|
Vol. 54, No. 4
267-270
EN
In this work bovine bone powder samples were irradiated at three different dose rates of 100, 260 and 630 kGy/min for the absorbed dose range of 3 to 110 kGy, using 10 MeV electron beam radiation. The samples were subjected to EPR measurement at room temperature in air. The variation of EPR signal intensities were constructed and evaluated base on quantitative data related to the absorbed doses. Moreover, they were compared with the obtained results from the samples irradiated by a 60Co gamma-ray source with a dose rate of 2.65 kGy/h. The time and temperature effects on the EPR response of this dosimeter were also studied. The results indicated that the bone sample was a suitable dosimeter especially for electron beam at high doses.
4
Content available Electrical properties of EVA/LDPE blends irradiated by high energy electron beam
Borhani M., Mirjalili G., Ziaie F., Bolorizadeh M.
Nukleonika
|
2007
|
Vol. 52, nr 2
77-81
EN
A series of low-density polyethylene (LDPE) blends with different amounts of poly(ethylene-vinyl acetate) (EVA) was prepared and irradiated with 10 MeV electron beam in the range of 50-380 kGy at room temperature in air. Some electrical properties of the blends such as surface and volume resistance, breakdown voltage, permittivity and loss factor were studied as a function of the EVA content and the radiation dose. It was revealed that the surface resistance and volume resistivity of the blends reach a maximum at a 170 kGy dose of radiation and 30 wt% of EVA. There is no considerable change at breakdown voltage permittivity and loss factor of the irradiated samples; however, the permittivity and the loss factor of the blends increase significantly with increasing amount of EVA contents.
5
Content available Effect of additives on thermal properties of electron beam irradiated LDPE foam
Ghaffari E., Ziaie F.
Nukleonika
|
2007
|
Vol. 52, nr 1
35-38
EN
In this work, the effects of some additives such as TMPTMA, a multifunctional monomer, and ZnO as the activator on thermal properties of electron beam irradiated LDPE foam were investigated. LDPE foams were made via adding 5 phr of azodicarbonamide as the blowing agent (ACA), 1-5 phr of ZnO and 1-5 phr of TMPTMA to the low-density polyethylene (LDPE) and then cross-linked using the 10 MeV electron beam at the dose range of 20 to 100 kGy. Effects of activator, multifunctional monomer and irradiation on thermal properties such as melting and degradation temperatures in cross-linked polyethylene foam were investigated. The thermal properties were measured by differential scanning calorimetry system (DSC).
6
Content available Investigation of high-dose irradiation effects on polystyrene calorimeter response
Ziaie F., Noori A.
Nukleonika
|
2006
|
Vol. 51, nr 3
175-178
EN
In this work attempts have been made to investigate the variation of polystyrene calorimeter response after frequent irradiations with an electron beam. Polystyrene calorimeters are routinely used in every radiation processing center as a traceable to NPL primary standard dosimeter. Thus, self designed high impact polystyrene as the calorimeter core was irradiated several times up to many thousands of kGy doses. After each irradiation, the specific heat capacity of the polystyrene as the main changeable parameter was measured using the differential scanning calorimeter system (DSC) in the practical temperature range of polystyrene calorimeter. Therefore, correction factors to calculate the precise absorbed dose were obtained. At the final stage, several these calorimeters were irradiated simultaneously along with two Risoe standard calorimeters and another correction factor for each tested calorimeter was calculated.
7
Content available Influence of temperature on breakdown voltage of 10 MeV electron beam irradiated LDPE and HDPE
Borhani M., Ziaie F., Bolorizadeh M., Mirjalili G.
Nukleonika
|
2006
|
Vol. 51, nr 3
179-182
EN
The paper presents measurements of the breakdown (dielectric strength) and dielectric constant of the low density polyethylene (LDPE) and high density polyethylene (HDPE) thin sheets, which were irradiated with a 10 MeV electron beam in the range of 0-470 kGy using a Rhodotron accelerator system. The tests were performed at temperatures ranging from 20°C to 110°C. Variation of the measured parameters vs. radiation absorbed dose and temperature were discussed.
8
Content available Mass throughput rate calculation for X-ray facilities
Ziaie F., Tahami S.
Nukleonika
|
2005
|
Vol. 50, nr 3
121-124
EN
Abstract In this work, the mass throughput rate in a radiation processing center, equipped with an X-ray facility, is calculated by means of a curve against the thickness of the material, along with the variation of dose uniformity. Therefore, depending on the desired dose value, the best thickness and the mass throughput rate can be calculated. The calculation results for the 5 and 10 MeV X-ray bremsstrahlung for polyethylene and wood as the irradiation products, have been obtained by using a Monte-Carlo computer code. In addition, the experimental results at the same geometry and materials were compared with those calculated.
9
Content available Dose rate effect on LDPE cross-linking induced by electron beam irradiation
Ziaie F., Anvari F., Ghaffari M., Borhani M.
Nukleonika
|
2005
|
Vol. 50, nr 3
125-127
EN
In this project, the radiation induced cross-linking in low-density polyethylene (LDPE) samples irradiated with the different dose rates of 5 MeV electron beam in the dose range of 20 up to 200 kGy were investigated and compared. The dose rate values were ranged from 13 to 300 kGy/min. The cross-linking of the samples were studied on the basis of gel content measurement and a hot set test. The yield of gel content showed slight increases with decreasing dose rate values. The same results were more clearly observed using the hot set test. It was concluded that, to irradiate the product based on LDPE, any variation in electron beam current causes different dose rates which, in turn, affect the absorbed dose value in materials.
10
Content available Manufacturing of a graphite calorimeter at Yazd Radiation Processing Center
Ziaie F.
Nukleonika
|
2004
|
Vol. 49, nr 4
159-162
EN
In this work, a few quasi-adiabatic graphite calorimeters of different dimensions are described. These calorimeters have been manufactured by ourselves and studied for accurate absorbed dose measurements in 10 MeV electron beam. In order to prove the accuracy and reliability of dose measurements with the use of the self designed graphite calorimeters (SDC), an inter comparison study was performed on these calorimeters and RisŘ's graphite calorimeters (SC, standard calorimeter) at different doses by using a Rhodotron accelerator. The comparison shows conclusively SDC of the optimal size, the results agreeing with those obtained with the SC within 1%.
11
Content available remote Using bone powder for dosimetric system EPR response under the action of γ irradiation
Ziaie F., Stachowicz W., Strzelczak G., Al-Osaimi S.
Nukleonika
|
1999
|
Vol. 44, nr 4
603-608
EN
Two sets of samples of the bovine bone powder and α-l-alanine crystalline powder were irradiated in a 60Co source using the doses from 5 kGy up to 120 kGy while recorded signals were subsequently measured with the EPR spectrometer at room temperature in the air. Quantitative data related to the absorbed dose of radiation were collected. Dose versus EPR signal intensity curves for both kinds of samples were constructed and evaluated.
PL
W pracy poddano napromieniowaniu w źródle Co-60 dawkami od 5 kGy do 120 kGy dwa zestawy próbek, sproszkowaną kość wołową oraz sproszkowaną krystaliczną α-Ianinę, a następnie przeprowadzono na spektrometrze EPR pomiary ilościowe zarejestrowanych sygnałów w temperaturze pokojowej, przy dostępie powietrza. Zgromadzono ilościowe dane odnoszące się do absorbowanej dawki promieniowania. Wykreślono krzywe zależności dawka - intensywność sygnału dla obu rodzajów próbek oraz dokonano oceny uzyskanych wyników.
first rewind previous Strona / 1 next fast forward last
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.