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Gamma radiation shielding properties of (x)Bi2O3–(0.5 - x)ZnO–0.2B2O3–0.3SiO2 glass system

Kheswa Bonginkosi Vincent

Nukleonika

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2024

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Vol. 69, No. 1

23--29

EN

Lead (Pb)-based materials are very effective in radiation shielding due to their high density of Pb. However, they pose health risks to humans because of the toxicity of lead. As a result, the investigation of radiation shielding properties of various lead-free glass materials has drawn a lot of attention from researchers. In this work, the γ radiation competence of the Bi2O3–ZnO–B2O3–SiO2 glass network was investigated, for the first time in the 0.015–15 MeV energy range, using Phy-X/PSD and XCOM software systems. The results showed that 45Bi2O3–5ZnO–20B2O3–30SiO2 glass sample has the highest linear attenuation coefficient, mass attenuation coefficient, and effective atomic number, and it has the lowest half-value layer, tenth-value layer, and mean-free path. Therefore, 45Bi2O3–5ZnO–20B2O3–30SiO sample is more effective on γ ray shielding than 10Bi2O3–40ZnO–20B2O3–30SiO, 20Bi2O3–30ZnO–20B2O3–30SiO, 30Bi2O3–20ZnO–20B2O3–30SiO, and 40Bi2O3–10ZnO–20B2O3–30SiO samples. The comparison of the results with the literature also revealed that the 45Bi2O3–5ZnO–20B2O3–30SiO glass sample is even more effective than some of Bi2O3-based glass systems, which were recently developed in the literature, by at least a factor of 2.

2

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

Sisin Noor Nabilah Talik, Anuar Muhammad Afiq, Dollah Norhayati, Razak Khairunisak Abdul, Algethami Merfat, Geso Moshi, Rahman Wan Nordiana

Polish Journal of Medical Physics and Engineering

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2022

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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.

3

Morphology and Structure of the Erbium Stabilized Bismuth Oxide Thin Films Deposited by PLD Technique

Kąc S., Szwachta G., Cieniek Ł., Moskalewicz T.

Archives of Metallurgy and Materials

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2019

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Vol. 64, iss. 3

969--974

EN

The aim of the work was to obtain thin bismuth oxide films containing, at room temperature, the Bi1,5Er0,5O3 phase. This phase corresponds to the structure of the high-temperature δ-Bi2O3 phase, in pure bismuth oxide, characterized by the highest ionic conductivity of all known solid state ionic conductors. The high-temperature δ-Bi2O3 phase with the face centered cubic structure, in pure bismuth oxide, occurs only at temperature above 730°C. Stabilization of the δ-Bi2O3 phase at room temperature was achieved by an addition of the erbium together with the employ-ment of the Pulsed Laser Deposition (PLD) technique. The influence of an amount of Er alloying and the film thickness on surface morphology, microstructure, phase composition of thin films were investigated. The velocity of deposition of thin layers of bismuth stabilized with erbium in the PLD process using the Nd: YAG laser was about 0.5 nm/s.The investigation results of erbium doped bismuth oxide thin films deposited onto (0001) oriented Al2O3 monocrystalline substrate are presented. Thin films of uniform thickness, without cracks, and porosity were obtained. All deposited thin films (regardless of the film thickness or erbia (Er2O3) content) exhibited a columnar structure. In films stabilized with erbium, up to approx. 250 nm thickness, the columns have a diameter at the base from 25 to 75 nm. The columns densely and tightly fill the entire volume of the films. With increasing of the film thickness increases, porosity also significantly increases. In thin layers containing from 20 to 30 mole % Er2O3 the main identified phase at room temperature is Bi1,5Er0,5O3. It is similar to the defective fluorite-type structure, and belongs to the Fm-3m space group. This phase corresponds to the structure of the high-temperature δ-Bi2O3 phase in pure bismuth oxide.

4

Osłony elastomerowe redukujące dawki promieniowania X w technikach tomografii komputerowe

Kusiak E., Zaborski M., Staniszewska A., Bem H., Szajerski P., Baryń W.

Polimery

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2013

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T. 58, nr 7-8

519--523

PL

Opracowano bezołowiowe osłony redukujące dawki promieniowania w diagnostyce technikami tomografii komputerowej. Podstawę stanowiła matryca z kauczuku naturalnego napełnionego tlenkami: bizmutu, wolframu lub gadolinu. Ze względu na generowanie przez bizmut wtórnego promieniowania fluorescencyjnego rozszerzono pierwotne składy kompozytów. Stwierdzono, że otrzymane kompozyty kauczuku naturalnego zawierające kombinacje tlenków metali charakteryzowały się dużymi wartościami masowych współczynników pochłaniania, wpływały na redukcję natężenia promieniowania padającego o energii: Eg = 60 keV o ok. 50 % a o energii Eg = 122 keV o ok. 20 %. Jednocześnie prawie wszystkie próbki wulkanizatów wykazywały korzystne właściwości wytrzymałościowe.

EN

We have developed lead-free shields reducing the radiation doses in the diagnostic computed tomography techniques. They are based on natural rubber matrix with oxides of bismuth, tungsten and gadolinium as fillers. Due to the generation of secondary fluorescence radiation by bismuth, the study was extended to other compositions. The obtained natural rubber composites containing the combinations of metal oxides were characterized by high values of the mass absorption coefficient, which effected in the reduction in the intensity of incident radiation with an energy Eg = 60 keV by about 50 % and for Eg = 122 keV by about 20 %. It should be noted that virtually all vulcanizates showed good strength properties.

5

Microstructure of doped Bi2O3 thin ﬁlms deposited by PLD technique

Kąc S., Moskalewicz T.

Inżynieria Materiałowa

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2013

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Vol. 34, nr 4

295--298

EN

The paper presents the investigation results of Mo doped Bi2O3 thin ﬁlms obtained by PLD technique, using Nd:YAG laser. Bismuth oxide is the material having wide application in the electronic and optical industry. The objective of our investigation is stabilization of high temperature δ phase to lower temperature, which permits widely take advantage of interesting properties of this material (good ion conductivity, changing conductivity with temperature). The Mo concentration and process parameters inﬂuence on the coating microstructure and properties were studied. The laser energy, the substrate temperature and the oxygen pressure in the vacuum chamber during deposition by PLD process inﬂuence strongly the chemical composition and morphology of deposited ﬁlms. The SEM, TEM, EDS and XRD investigation results of the films microstructure are presented in the paper. The results of investigations carried out indicate that it is possible to transfer stoichiometric composition of Mo doped Bi2O3 from target to substrate. In deposited thin ﬁlms high temperature δ-Bi2O3 phase at room temperature was obtained.

PL

W publikacji przedstawiono wyniki badań cienkich warstw domieszkowanego molibdenem tlenku bizmutu wytwarzanych techniką ablacji laserowej (PLD) z wykorzystaniem lasera impulsowego Nd:YAG. Tlenek bizmutu to materiał szeroko stosowany w przemyśle elektronicznym i optyce. Celem przeprowadzonych badań jest stabilizacja wysokotemperaturowej fazy δ do niższej temperatury, co pozwoli lepiej wykorzystać interesujące własności tego materiału (dobre przewodnictwo jonowe, zmianę przewodności elektrycznej z temperaturą). W pracy badano wpływ koncentracji Mo i parametrów procesu PLD na mikrostrukturę i własności cienkich warstw tlenku bizmutu. Energia wiązki lasera, temperatura podłoża i ciśnienie tlenu w komorze reakcyjnej podczas procesu PLD istotnie wpływają na skład chemiczny i morfologię wytwarzanych warstw. W pracy są prezentowane wyniki badań cienkich warstw za pomocą SEM, TEM, EDS i XRD. Wyniki przeprowadzonych badań wykazują, że jest możliwe stechiometryczne przenoszenie domieszkowanego Mo tlenku bizmutu z odparowanej wiązką lasera tarczy na podłoże. W wytworzonych cienkich warstwach otrzymano wysokotemperaturową fazę δ-Bi2O3 w temperaturze otoczenia.

6

Wpływ właściwości kwasowo-zasadowych i redukowalności katalizatorów Bi-Si-O modyfikowanych wybranymi jonami metali na ich aktywność w procesie OCM-CO2

Vogt O., Ogonowski J., Litawa B.

Czasopismo Techniczne. Chemia

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2008

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R. 105, z. 1-Ch

149-154

PL

Badano wpływ właściwości kwasowo-zasadowych oraz redukowalności katalizatora Bi-Si-O modyfikowanego jonami chromu, manganu, miedzi i cynku na aktywność w procesie OCM-CO[2]. Najwyższą aktywność w badanym procesie wykazał katalizator modyfikowany jonami cynku. Kontaktowi temu odpowiadały również największa konsumpcja wodoru oraz najmniejsze stężenie centrów kwasowych i zasadowych.

EN

The influence of the acid-basic properties and the reducibility of Bi-Si-O catalysts modified with ions of chromium, manganese, copper and zinc on their activity in the OCM-CO[2] process was studied. Catalyst modified with ions of zinc showed the highest activity in the studied process. This catalysts showed also the largest consumption of hydrogen and the lowest concentration of the acidic and basic centres.

7

Structure and electrical properties of oxide-ion conductors in the Bi3NbO7-Bi3YO6 system

Kozanecka-Szmigiel A., Krok F., Abrahams I., Wrobel W., Chan S.C.M., Dygas J.R.

Materials Science Poland

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2006

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Vol. 24, No. 1

31--37

EN

A study of the structure and electrical conductivity of Bi3Nb1-xYxO7-x is presented. X-ray diffraction confirms full solid solution formation in this system, with the adoption of a fluorite-type structure. Superlattice ordering of the anion sublattice is evident in neutron diffraction data, the nature of which varies with composition. At low values of x, long-range ordering is present, whereas above x = 0.4 only local ordering is observed. Arrhenius plots of the total electrical conductivity of all samples containing yttrium show two linear regions with different activation energies, with evidence for a phase transition between 450 and 680 °C.

8

Oxide-ion conductors for fuel cells

Krok F., Abrahams I., Wrobel W., Kozanecka-Szmigiel A., Dygas J.R.

Materials Science Poland

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2006

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Vol. 24, No. 1

13--22

EN

The principal materials used in the construction of solid oxide fuel cells (SOFCs) are discussed. Some of the problems encountered with high temperature fuel cells (HT-SOFCs) might be overcome by lowering the operating temperature to 500-700 °C, through the development of suitable materials for intermediate temperature fuel cells IT-SOFCs. Candidate electrolyte materials are discussed, including cerium gallium oxide, lanthanum strontium gallium magnesium oxide, and electrolytes based on doped bismuth oxide. While high ionic conductivities can readily be achieved in these materials at intermediate temperatures, stability in reducing atmosphere is still a problem. This might be overcome by careful chemical design of electrolytes containing stabilising dopants. Two zirconia-doped bismuthate systems are discussed in this respect. In both cases, the obtained materials exhibit different structures - one is Bi3Nb1-xZrxO7-x/2 of the ?-Bi2O3 type, and the other, Bi4V2-2xZrxO11-x, has a layered structure of the Aurivillius type.