scholarly journals A COMPARATIVE STUDY OF THE RADIOLYSIS OF USED TRANSFORMER OIL AND OIL CONTAINING 1, 2, 4-TRICHLORBENZENE UNDER THE INFLUENCE OF GAMMA-RADIATION

2019 ◽  
pp. 191-195
Author(s):  
Z.I. Iskenderova
Keyword(s):  
Hydrogen Peroxide ◽  
Comparative Study ◽  
Dissolved Oxygen ◽  
Gamma Radiation ◽  
Ir Spectra ◽  
Ph Value ◽  
Absorbed Dose ◽  
Transformer Oil ◽  
Ph Indicator ◽  
Absorbed Doses

A comparative study of the radiolysis of used transformer oil and oil containing 1, 2, 4-trichlorbenzene (TCB) under the influence of gamma-radiation was carried out. Dependence of concentration of H2, H2O2, pH-indicator and IR-spectra of γ-irradiated samples from absorbed doses in the range of 4…136 kGy was studied. The pH-value dependence and concentration of hydrogen peroxide as a function of the absorbed dose is studied. Irradiation leads to increasing of acidity, related with dechlorination of TCB molecules. It is found that during the radiolysis of transformer oil containing TCB in the presence of dissolved oxygen, radiation-initiated oxidation of the oil takes place (formation of H2O2, CO2).

Radiolysis of transformer oil in presence of trichlorbenzen and nano-γ-Al2O3

2021 ◽  
Vol 2 ◽  
pp. 80-85
Author(s):  
Z. I. Iskenderova ◽  
Keyword(s):  
Absorbed Dose ◽  
Chemical Yield ◽  
Transformer Oil ◽  
Nano Particles ◽  
Electronic Excitation Energy ◽  
Hydrogen Atoms ◽  
Ph Indicator ◽  
Radiation Chemical ◽  
Initial Concentration ◽  
Main Components

In this work, a comparative study of the kinetics of changes in the pH indicator, the formation of H2O2 and CO2 depending on the absorbed dose at the radiolysis of TCB containing transformer oil in the presence and without nano-γ-Al2O3 under the action of γ radiation was carried out. During radiolysis of both systems (TСB + transformer oil and TСB + transformer oil + 0.1 g of nano-γ-Al2O3), the radiation-chemical yield of CO2 decreases with an increase in the initial concentration of TCB, although at the presence of nano-particles, the values of the radiation-chemical riels of CO2 become less. Unlike CO2, the radiation-chemical yields of H2O2 increase with an increase in the initial concentration of TCB, but their values are less in the presence of nano-γ-Al2O3. The results obtained are explained by the reactions of active particles, radiolysis of the main components of transformer oil, such as hydrogen atoms and hydrocarbon radicals with TCB and dissolved oxygen molecules. In addition, there is a transfer of electronic excitation energy from alkane and cycloalkane molecules to aromatic hydrocarbon molecules. The effect of nano-γ-Al2O3 on the radiolysis of the mixture is discussed on the basis of the reaction of electron and hole centers with the molecules of the components of the irradiated mixture.

Comparative Study Between Geant4, MCNP6 and Experimental Results Against Gamma Radiation Comes from a Cobalt-60 Source

2020 ◽  
Vol 75 (5) ◽  
pp. 507-511
Author(s):  
Y. El-Ouardi ◽  
A. Dadouch ◽  
A. Aknouch ◽  
M. Mouhib ◽  
A. Maghnouj ◽  
...  
Keyword(s):  
Comparative Study ◽  
Gamma Radiation ◽  
Experimental Results

Oxidation of hydrogen peroxide at the dropping mercury electrode

1984 ◽  
Vol 49 (10) ◽  
pp. 2320-2331 ◽  
Author(s):  
Miroslav Březina ◽  
Martin Wedell
Keyword(s):  
Hydrogen Peroxide ◽  
Superoxide Anion ◽  
Ph Value ◽  
Mercury Electrode ◽  
Electrode Process ◽  
Electrochemical Processes ◽  
Dropping Mercury Electrode ◽  
Oxidation Of Hydrogen ◽  
Decreasing Ph ◽  
Rate Controlling Step

Reduction of oxygen and oxidation of hydrogen peroxide at the dropping mercury electrode are electrochemical processes strongly influenced both by the pH value and the anions in solution. With decreasing pH, both processes become irreversible, especially in the presence of anions with a negative φ2 potential of the diffusion part of the double layer. In the case of irreversible oxygen reduction, the concept that the rate-controlling step of the electrode process is the acceptance of the first electron with the formation of the superoxide anion, O2-, was substantiated. Oxidation of hydrogen peroxide becomes irreversible at a lower pH value than the reduction of oxygen. The slowest, i.e. rate-controlling step of the electrode process in borate buffers at pH 9-10 is the transfer of the second electron, i.e. oxidation of superoxide to oxygen.

scholarly journals Regression Analysis of Orthogonal, Cylindrical and Multivariable Color Parameters for Colorimetric Surface pH Measurement of Materials

Molecules ◽  
2021 ◽  
Vol 26 (12) ◽  
pp. 3682
Author(s):  
Katarína Vizárová ◽  
Izabela Vajová ◽  
Naďa Krivoňáková ◽  
Radko Tiňo ◽  
Zdenko Takáč ◽  
...  
Keyword(s):  
Ph Value ◽  
Critical Factor ◽  
Ph Measurement ◽  
Ph Indicator ◽  
Water Quality Control ◽  
Quality Management Systems ◽  
Surface Ph ◽  
Regression Parameters ◽  
Ph Detection

The surface pH is a critical factor in the quality and longevity of materials and products. Traditional fast colorimetric pH detection-based tests such as water quality control or pregnancy tests, when results are determined by the naked eye, cannot provide quantitative values. Using standard pH papers, paper-printed comparison charts, or colorimetric microfluidic paper-based analytical devices is not suitable for such technological applications and quality management systems (QMSs) where the particular tested material should contain a suitable indicator in situ, in its structure, either before or after the process, the technology or the apparatus that are being tested. This paper describes a method based on the combination of impregnation of a tested material with a pH indicator in situ, its exposure to a process of technology whose impact on pH value is to be tested, colorimetric pH measurement, and approximation of pH value using derived pH characteristic parameters (pH-CPs) based on CIE orthogonal and cylindrical color variables. The hypotheses were experimentally verified using the methyl red pH indicator, impregnating the acid lignin-containing paper, and preparing a calibration sample set with pH in the range 4 to 12 using controlled alkalization. Based on the performed measurements and statistical evaluation, it can be concluded that the best pH-CPs with the highest regression parameters for pH are √∆E, ln (a),√∆H (ab), a/L, h/b and ln (b/a). The experimental results show that the presented method allows a good estimation of pH detection of the material surfaces.

scholarly journals α-Particle-induced DNA damage tracks in peripheral blood mononuclear cells of [223Ra]RaCl2-treated prostate cancer patients

2021 ◽  
Author(s):  
S. Schumann ◽  
U. Eberlein ◽  
C. Lapa ◽  
J. Müller ◽  
S. Serfling ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Dna Damage ◽  
Cancer Patients ◽  
Peripheral Blood Mononuclear Cells ◽  
Peripheral Blood ◽  
Mononuclear Cells ◽  
Absorbed Dose ◽  
Peripheral Blood Mononuclear ◽  
Absorbed Doses ◽  
Blood Mononuclear Cells

Abstract Purpose One therapy option for prostate cancer patients with bone metastases is the use of [223Ra]RaCl2. The α-emitter 223Ra creates DNA damage tracks along α-particle trajectories (α-tracks) in exposed cells that can be revealed by immunofluorescent staining of γ-H2AX+53BP1 DNA double-strand break markers. We investigated the time- and absorbed dose-dependency of the number of α-tracks in peripheral blood mononuclear cells (PBMCs) of patients undergoing their first therapy with [223Ra]RaCl2. Methods Multiple blood samples from nine prostate cancer patients were collected before and after administration of [223Ra]RaCl2, up to 4 weeks after treatment. γ-H2AX- and 53BP1-positive α-tracks were microscopically quantified in isolated and immuno-stained PBMCs. Results The absorbed doses to the blood were less than 6 mGy up to 4 h after administration and maximally 16 mGy in total. Up to 4 h after administration, the α-track frequency was significantly increased relative to baseline and correlated with the absorbed dose to the blood in the dose range < 3 mGy. In most of the late samples (24 h – 4 weeks after administration), the α-track frequency remained elevated. Conclusion The γ-H2AX+53BP1 assay is a potent method for detection of α-particle-induced DNA damages during treatment with or after accidental incorporation of radionuclides even at low absorbed doses. It may serve as a biomarker discriminating α- from β-emitters based on damage geometry.

scholarly journals Killing of Bacillus Spores by Aqueous Dissolved Oxygen, Ascorbic Acid, and Copper Ions

2003 ◽  
Vol 69 (4) ◽  
pp. 2245-2252 ◽  
Author(s):  
J. B. Cross ◽  
R. P. Currier ◽  
D. J. Torraco ◽  
L. A. Vanderberg ◽  
G. L. Wagner ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Ascorbic Acid ◽  
Dissolved Oxygen ◽  
Hydroxyl Radicals ◽  
Fenton Reaction ◽  
Copper Ions ◽  
Transition Metal Ions ◽  
Fenton Reagent ◽  
Bacillus Spores ◽  
Modified Fenton

ABSTRACT An approach to decontamination of biological endospores is discussed. Specifically, the performance of an aqueous modified Fenton reagent is examined. A modified Fenton reagent formulation of cupric chloride, ascorbic acid, and sodium chloride is shown to be an effective sporicide under aerobic conditions. The traditional Fenton reaction involves the conversion of hydrogen peroxide to hydroxyl radical by aqueous ionic catalysts such as the transition metal ions. Our modified Fenton reaction involves the conversion of aqueous dissolved oxygen to hydrogen peroxide by an ionic catalyst (Cu2+) and then subsequent conversion to hydroxyl radicals. Results are given for the modified Fenton reagent deactivating spores of Bacillus globigii. A biocidal mechanism is proposed that is consistent with our experimental results and independently derived information found in the literature. This mechanism requires diffusion of relatively benign species into the interior of the spore, where dissolved O2 is then converted through a series of reactions which ultimately produce hydroxyl radicals that perform the killing action.

scholarly journals Is nuclear medicine really safe?

2002 ◽  
Vol 45 (spe) ◽  
pp. 115-118
Author(s):  
Nicole Colas-Linhart
Keyword(s):  
Nuclear Medicine ◽  
Human Serum Albumin ◽  
Radiation Dose ◽  
Serum Albumin ◽  
Human Serum ◽  
Absorbed Dose ◽  
Cellular Level ◽  
Whole Body ◽  
Absorbed Doses ◽  
Standard Models

In nuclear medicine, radiation absorbed dose estimates calculated by standard models at the whole body or organ are very low. At cellular level, however, the heterogeneity of radionuclide distributions of radiation dose patterns may be significant. We present here absorbed doses at cellular level and evaluate their possible impact on the usually assumed risk/benefit relationships in nuclear medicine studies. The absorbed dose values calculated are surprisingly high, and are difficult to interpret. In the present study, we show calculated doses at the cellular level and discuss possible biological consequences, for two radiopharmaceuticals labelled with technetium-99m: human serum albumin microspheres used for pulmonary scintigrapies and HMPAO used to labelled leukocytes.

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