Wyniki wyszukiwania - Biblioteka Nauki

1

Radiation-induced sulfur dioxide removal

100%

Chmielewski A.

Nukleonika

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2000

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tom Vol. 45, nr 1

31-38

EN

The biggest source of air pollution is the combustion of fossil fuels, where pollutants such as particulate, sulfur dioxide (SO2), nitrogen oxides (NOx), and volatile organic compounds (VOC) are emitted. Among these pollutants, sulfur dioxide plays the main role in acidification of the environment. The mechanism of sulfur dioxide transformation in the environment is partly photochemical. This is not direct photooxidation, however, but oxidation through formed radicals. Heterogenic reactions play an important role in this transformation as well; therefore, observations from environmental chemistry can be used in air pollution control engineering. One of the most promising technologies for desulfurization of the flue gases (and simultaneous denitrification) is radiation technology with an electron accelerator application. Contrary to the nitrogen oxides (NOx) removal process, which is based on pure radiation-induced reactions, sulfur dioxide removal depends on two pathways: a thermochemical reaction in the presence of ammonia/water vapor and a radiation set of radiochemical reactions. The mechanisms of these reactions and the consequent technological parameters of the process are discussed in this paper. The industrial application of this radiation technology is being implemented in an industrial pilot plant operated by INCT at EPS Kawęczyn. A full-scale industrial plant is currently in operation in China, and two others are under development in Japan and Poland.

2

Combination of methods of thermal and radiation treatment of sediments associated with PCBs : the Delor type

80%

Fülöp M. , Šagátová A. , Benkovský I. , Prokes K. , Foltinova L.

Nukleonika

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2021

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tom Vol. 66, No. 4

207--211

EN

An efficient method of burning polychlorinated biphenyls (PCBs) is often used to remove the environmental burden of PCBs. However, combustion produces toxic dioxins and furans (PCDD/F), so residents are increasingly rejecting this method. The heat treatment (HT) method does not burn PCBs but evaporates it from sediments. Even in this process, PCDD/Fs are formed to a lesser extent, which are destroyed by radiation processing (RP) following the HT. At the same time, the RP method degrades PCB congeners down to biphenyls, which decompose easily in the environment. A block assembly of a complex synergistic combination of equipment for methods of thermal (HT) and radiation (RP) destruction of PCBs in sediments is proposed. The efficacy of this complex was preliminarily determined at a level of 70-fold reduction in PCB concentration in sediments. To achieve a higher reduction factor in the concentration of PCBs, possible procedures for optimizing the settings of individual devices of this complex are presented.

3

Effect of electron radiation on sugar content in inverted liquid sugar

80%

Podadera P. , Sabato S. F.

Nukleonika

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2009

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tom Vol. 54, No. 2

85-87

EN

Inverted liquid sugar is a mixture of sucrose, glucose and fructose, which shows its relevant characteristic on high sweetness power. Ionizing radiation has been applied to different kind of food and ingredients for different reasons, such as pathogens reduction, disinfestations, quarantine purposes, ripening delay among others. Radiation from an electron beam can be utilized as a technique to treat this ingredient because it can process a great volume of material per unit of time. The main goal of this paper was to verify the effect of radiation on the properties of inverted liquid sugar. This ingredient was irradiated in an electron accelerator (Radiation Dynamics) at a dose ranging from 5 to 50 kGy. Sucrose content measurements were reduced by 23% at 30 kGy when compared to control and the reduced sugar content increased around 11%. Density and moisture values were not affected by radiation. The total soluble solids (Brix degrees) rose in function of the absorbed dose.

4

Decomposition of toluene in air mixtures under electron beam irradiation

80%

Sun Y. , Chmielewski A. G. , Bułka S. , Zimek Z.

Nukleonika

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2009

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tom Vol. 54, No. 2

65-70

EN

The model gases of toluene-air mixtures were prepared by blowing technical air into liquid toluene and then irradiated with an ILU-6 accelerator located at the Institute of Nuclear Chemistry and Technology (INCT), Poland. It was found that the decomposition efficiency of toluene increases with absorbed dose and decreases with initial concentration of toluene. At 14.5 kGy dose, the decomposition efficiencies of toluene were 50, 37 and 34.5% for the initial concentrations of toluene 32.0, 63.4 and 78.0 ppm, respectively. At 58.0 kGy dose, the decomposition efficiencies of toluene were 93.8 and 78.1%, the initial concentrations of toluene being 32.0 and 63.4 ppm, respectively. Benzaldehyde was identified as one of the by-products of toluene decomposition in an air mixture. The decomposition efficiency and by-product formation under EB irradiation were compared between toluene and 4-chlorotoluene.

5

A comparison of the basic photon and electron dosimetry data for Neptun 10PC linear accelerators

80%

Shokrani P. , Monadi S.

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tom Vol. 53, No. 4

181-185

EN

. In recent years the similarity of dosimetric characteristics of modern linear accelerators with the same make, model and nominal energy, has become more common. The goal of this study was to quantitatively investigate the reproducibility of the basic photon and electron dosimetry data from Neptun 10PC accelerators across the institutions. In the current study, the photon and electron dosimetry data collected during acceptance and initial commissioning of six Neptun 10PC linear accelerators are analyzed. The dates of original installations of these six machines were evenly spread out over a 5 year period and the series of measurements were conducted during an average of 1-2 months after original installations. All units had identical energies and beam modifiers. For photon beams, the collected data include depth dose data, output factors and beam profile data in water. For electron beams, in addition to depth dose data and output factors, the effective source skin distance for 10 × 10 cm field size is also presented. For most beam parameters the variation (one standard deviation), was less than 1.0% (less than 2% for 2 parameters). A variation of this magnitude is expected to be observed during annual calibration of well-maintained accelerators. In conclusion, this study is presenting a consistent set of data for Neptun 10PC linear accelerators. This consistency implies that for this model, a standard data set of basic photon and electron dosimetry could be established, as a guide for future commissioning, beam modeling and quality assurance purposes.

6

Trochoidalny monochromator energii elektronów

80%

Pelc A.

Elektronika : konstrukcje, technologie, zastosowania

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2009

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tom Vol. 50, nr 1

112-114

PL

Trochoidalny monochromator energii elektronów (TEM) jest szczególnie efektywnym monochromatorem w przypadku wytwarzania wiązek elektronów o niskiej energii. W pracy tej została opisana zasada działania TEM. Przy użyciu skonstruowanego TEM otrzymano wiązkę elektronów o energiach z przedziału od około 0 do 10 eV. Najmniejszy rozrzut energetyczny otrzymanej wiązki elektronowej wynosił 52 meV przy natężeniu prądu elektronowego 3 nA. Przy większym rozrzucie energetycznym - 150 meV, natężenie prądu elektronowego wynosiło 70 nA.

EN

Electron monochromator being operated with an axial (parallel to electron beam) magnetic field is very suitable for the very low energy electron beams. This type of monochromator is called Trochoidal Electron Monochromator (TEM). The principle of operation and tests of the TEM are described in this contribution. Using newly constructed TEM the electron beam with energy range from about 0 to 10 eV was achieved. We achieved maximum electron energy resolution (at FWHM) of 52 meV, with rather small electron current intensity of 3 nA. At lower resolution of 150 meV the electron current intensity was 70 nA, respectively.

7

Position of effective electron source for shielded electron beams from a therapeutic linear accelerator

80%

Al Asmary M. , Ravikumar M.

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tom 16

|

nr 1

11-21

EN

The effective electron source positions for the standard electron cones and for the shielded field sizes with cerrobend inserts were measured based on Inverse Square Law (ISL) and the Inverse Slope (IS) method for various electron energies.The charge measurements were carried out using a 0.6 cc ion chamber (PTW, Type 30001) connected to a PTW Unidos E digital electrometer in a polystyrene phantom for electron beam energies of 6-18 MeV. The resultant charge for 100 MU setting was measured at nominal source to surface distances (SSDs) of 100-120 cm for cone and cerrobend defined field sizes.The effective SSD (SSDeff) was found to be different for the same field size defined by electron applicator and the cerrobend shield placed in 25×25 cm standard cone. Strong dependency of SSDeff with field size and electron beam energy was noticed.The results from the ISL and IS method are consistent, hence either of the two methods can be used to determine the effective source position. Whenever treatment is to be given with shielded electron portal, the SSDeff for that field needs to be determined. Same SSDeff as that of the standard cone can be used for minimum shielded electron portals.

8

Computer-simulated degradation of CF3Cl, CF2Cl2, and CFCl3 under electron beam irradiation

80%

Kabasa S. , Sun Y. , Chmielewski A. G. , Nichipor H.

Nukleonika

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2023

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tom Vol. 68, No. 3

67--76

EN

Electron beam treatment technologies should be versatile in the removal of chlorofl uorocarbons (CFCs) owing to their exceptional cross sections for the thermal electrons generated in the radiolysis of air. Humidity, dose rates, O2 concentration, and CFC concentration infl uence the effi ciency of the destruction process under electron beam treatment. Computer simulations have been used to theoretically demonstrate the destruction of chlorotrifl uoromethane (CF3Cl), dichlorodifl uoromethane (CF2Cl2), and trichlorofl uoromethane (CFCl3) in the air (N2 + O2: 80% + 20%) in room temperature up to a dose of 13 kGy. Under these conditions, it is predicted that the removal effi ciency is in the order CF3Cl (0.1%) < CF2Cl2 (7%) < CFCl3 (34%), which shows the dependence of the process on the number of substituted Cl atoms. Dissociative electron attachment with the release of Cl– is the primary process initiating the destruction of CFCs from the air stream. Reactions with the first excited state of oxygen, namely, O(1 D), and charge-transfer reactions further promote the degradation process. The degradation products can be further degraded to CO2, Cl2, and F2 by prolonged radiation treatment. Other predicted products can also be removed through chemical processes.

9

Zastosowanie wiązki elektronowej w addytywnych metodach wytwarzania

80%

Zawada A. , Ażgin J. , Siedlecki M. , Kapelski D. , Czopik A.

|

tom Vol. 60, nr 12

53--55

PL

W artykule opisano zasadę działania drukarek 3D do wytwarzania elementów metalowych, wykorzystujących wiązkę elektronów jako źródło energii. Porównano właściwości tych urządzeń z urządzeniami, w których źródło energii stanowi laser. Opisano także warunki, jakie musi spełniać wiązka elektronowa w drukarkach 3D oraz opisano prace eksperymentalne, prowadzone w Sieci Badawczej Łukasiewicz - ITR.

EN

The article describes the principle of operation of 3D printers for manufacturing of metal components using an electron beam as an energy source. The properties of these devices were compared to those in which the laser is source of energy. Properties of electron beam in 3D printers were described, and experimental work carried out in the Łukasiewicz Research Network - ITR was also described.

10

Iron oxide(III) nanoparticles fabricated by electron beam irradiation method

80%

Zhao B. , Wang Y. , Guo H. , Wang J. , He Y. , Jiao Z. , Wu M.

Materials Science Poland

|

2007

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tom Vol. 25, No. 4

1143--1148

EN

Iron oxide(III) nanoparticles were fabricated by the electron beam irradiation method. The structure and morphology of the iron oxide nanoparticles were analyzed by XRD, TEM, AFM and FTIR. Phase transformation temperatures were determined by DSC-TGA. Results showed that the phase transition point and melting point decreased greatly. The size effects were discussed to explain the reason.

11

Influence of temperature on breakdown voltage of 10 MeV electron beam irradiated LDPE and HDPE

70%

Borhani M. , Ziaie F. , Bolorizadeh M. , Mirjalili G.

Nukleonika

|

2006

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tom 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.

12

Investigation of high-dose irradiation effects on polystyrene calorimeter response

70%

Ziaie F. , Noori A.

Nukleonika

|

2006

|

tom 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.

13

Electron beam-based fast prototyping - state of theart

70%

Węglowski M. S.

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tom Vol. 62, No. 1

29--35

PL

Szybkie prototypowanie przy użyciu wiązki elektronów i materiału deponowanego w postaci drutu jest wydajną metodą wytwarzania elementów o skomplikowanych kształtach z kosztownych stopów technicznych metali, takich jak stale stopowe, stopy niklu lub tytanu. Zapotrzebowanie na metody szybkiego prototypowania związane jest z rozwojem nowych technologii w przemyśle motoryzacyjnym, lotniczym i budowie maszyn. W pracy omówiono zalety metod szybkiego prototypowania w porównaniu do tradycyjnych technologii przetwarzania. Przedstawiono idee samej metody oraz podstawowe parametry procesu. Technologia szybkiego prototypowania przy użyciu drutu i wykorzystująca jako źródło energii wiązkę elektronów powinna zyskać uznanie wśród polskich przedsiębiorców, którzy są nastawieni na wprowadzanie innowacyjnych rozwiązań w swoich przedsiębiorstwach.

EN

Fast prototyping involving the use of an electron beam and a deposited material in the form of a wire is an efficient method enabling the making of elements having complicated shapes and made of expensive technical alloys, e.g. alloy steels, nickel or titanium alloys. The demand for fast prototyping results from the development of new technologies in the automotive, aviation and machine-building industries. The article discusses the advantages of fast prototyping methods confronted with conventional prototyping methods as well as presents ideas behind the fast prototyping and primary process parameters. The fast prototyping technology involving the use of a wire and an electron beam as the source of energy should gain recognition among Polish entrepreneurs intended to implement innovative solutions in their companies.

14

Bone powder as EPR dosimetry system for electron and gamma radiation

70%

Ziaie F. , Hajiloo N. , Fathollahi H. , Mehtieva S. I.

Nukleonika

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2009

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tom 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.

15

Stability study of free radicals in 10 MeV electron beam irradiated quartz as an EPR dosimetry method

70%

Ziaie F. , Mohammadzadeh A. , Modarresi M.

Nukleonika

|

2009

|

tom 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.

16

10 MeV electron beam cross-linking of plasticized PVC in presence of EHPTM and TAC additives

70%

Behjat A. , Gheysari D.

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tom Vol. 53, No. 2

57-62

EN

Irradiation of plasticized PVC (PPVC) compound containing a cross-linking monomer was carried out by a 10 MeV electron beam. This compound mainly is used as insulation in the wire and cable industry. The cross-linking monomers EHPTM and TAC at different ratio of 3, 6, and 9 phr were used. The dose range was varied from 50 to 150 kGy. The effects of monomers and radiation dose on radiation cross-linking were studied by hot-set testing and gel content measurements. In the absence of EHPTM and TAC, cross-linking did not take place by high energy electron beam at any dose and samples had very large elongation in a hot-set apparatus. But in the presence of these monomers, gel content augmented with an increase in radiation dose and EHPTM level. The highest value of approximately 76% gel content was obtained. In this case the lowest hot-set value was about 12%. Also, tensile strength, elongation at break, modulus, volume resistivity, dielectric strength, and limiting oxygen index of samples were examined. It was found that the mechanical properties of samples containing EHPTM and TAC improved significantly with increasing radiation dose. But for PPVC samples loaded with EHPTM, tensile strength values were higher than those of the loaded ones with TAC at all radiation doses. From the hot-set data it is concluded that the samples loaded with EHPTM had a low thermal expansion compared with samples loaded with TAC. The results indicated that EHPTM is a more effective cross-linking agent for PPVC compound compared with TAC.

17

Influence of PEG-coated Bismuth Oxide Nanoparticles on ROS Generation by Electron Beam Radiotherapy

70%

Sisin N. N. T. , Anuar M. A. , Dollah N. , Razak K. A. , Algethami M. , Geso M. , Rahman W. N.

Polish Journal of Medical Physics and Engineering

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2022

|

tom Vol. 28, Iss. 2

69--76

EN

Introduction: Nanoparticles (NPs) have been proven to enhance radiotherapy doses as radiosensitizers. The introduction of coating materials such as polyethylene glycol (PEG) to NPs could impact the NPs’ biocompatibility and their effectiveness as radiosensitizers. Optimization of surface coating is a crucial element to ensure the successful application of NPs as a radiosensitizer in radiotherapy. This study aims to investigate the influence of bismuth oxide NPs (BiONPs) coated with PEG on reactive oxygen species (ROS) generation on HeLa cervical cancer cell line. Material and methods: Different PEG concentrations (0.05, 0.10, 0.15 and 0.20 mM) were used in the synthesis of the NPs. The treated cells were irradiated with 6 and 12 MeV electron beams with a delivered dose of 3 Gy. The reactive oxygen species (ROS) generation was measured immediately after and 3 hours after irradiation. Results: The intracellular ROS generation was found to be slightly influenced by electron beam energy and independent of the PEG concentrations. Linear increments of ROS percentages over the 3 hours of incubation time were observed. Conclusions: Finally, the PEG coating might not substantially affect the ROS generated and thus emphasizing the functionalized BiONPs application as the radiosensitizer for electron beam therapy.

18

Physical characteristics of photon beam from a CLINAC-DBX single energy accelerator

70%

Umbarkar R. , Supe S. , Pandey M. , Ashok J.

Polish Journal of Medical Physics And Engineering

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2011

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tom 17

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nr 3

143-151

EN

Commissioning beam data are treated as a reference and ultimately used by treatment planning systems, therefore, it is vitally important that the collected data are of the highest quality, in order to avoid dosimetric and patient treatment errors that may subsequently lead to a poor radiation outcome. High-energy photon and electron beams from different accelerators of the same nominal energy may have different dosimetric characteristics due to differences in target and flattening filter materials, accelerator guide and collimator designs. In the present study, clinically pertinent data for the available photon energy were investigated. For making measurements in water, first time in India, a three dimensional radiation field analyzer RFA (CRS- Scan -O-Plan) was used. For absolute dosimetry and other measurements like relative output factors, wedge factors etc., a DOSE1 electrometer (Scanditronix Wellhofer) in a white polystyrene was employed. All the measured data were utilized as an input to the ECLIPSE treatment planning system for further clinical use.

19

Dose rate effect on LDPE cross-linking induced by electron beam irradiation

70%

Ziaie F. , Anvari F. , Ghaffari M. , Borhani M.

Nukleonika

|

2005

|

tom 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.

20

Decomposition of diclofenac in sewage from municipal wastewater treatment plant using ionizing radiation

70%

Bojanowska-Czajka A.

Nukleonika

|

2021

|

tom Vol. 66, No. 4

201--206

EN

The decomposition of diclofenac (DCF) in sewage sludge from municipal wastewater treatment plant was investigated. It was found that adsorption of DCF on sludge is about 40%. Compared to previous studies, where the degradation yield in aqueous solution was 100%, in those experiments at the dose up to 5 kGy, only 50% of initial DCF concentration of 50 mg L−1 was decomposed in sediment and in solution over the sediment. The experiments were carried out using both gamma radiation and electron beam. It has been observed that DCF in the aqueous phase, above the sediment, was decomposed with the same efficiency using both gamma radiation and electron beam. Whereas for DCF in the sediment, a higher degradation efficiency was found when gamma radiation was applied. This is most likely due to the limited penetration depth of the electron beam into the sludge layer. It was shown that the applied peroxide addition (in a stoichiometric amount needed for complete mineralization of 50 mg L−1 DCF) did not cause increase in yield of DCF decomposition.