scholarly journals Effects of Storage Time and Pre-Etching Treatment of CR-39 Detectors on Their Response to Alpha Radiation Exposure

2021 ◽  
Vol 18 (16) ◽  
pp. 8346
Author(s):  
Miroslaw Janik ◽  
Md. Mahamudul Hasan ◽  
Peter Bossew ◽  
Norbert Kavasi
Keyword(s):  
Carbon Dioxide ◽  
Storage Time ◽  
Alpha Particles ◽  
Hot Water ◽  
Evaluation Procedure ◽  
Etching Time ◽  
Nuclear Track Detectors ◽  
Carbon Dioxide Atmosphere ◽  
Track Area ◽  
Cr 39 Detectors

Radon passive monitors based on solid state nuclear track detectors (SSNTD), especially CR-39, are widely used in radon and thoron studies. They may be subjected to the influence of external factors, like changing of temperature, humidity, and pressure, both before and during the measurement. Evaluation of the exposed detectors involves chemical processing, whose conditions also influence the measurement results. The aim of this study was to check several factors, as to whether they may modify the response of CR-39 detector: concerning the phase before evaluation, storage time, and temperature during storage; and concerning the evaluation procedure, etching time, and pre-etching treatment using hot water and carbon dioxide atmosphere. Two experiments were conducted by irradiation of CR-39 detectors using alpha particles emitted from a mono-energetic 241Am source and exposed in radon atmosphere. Track density dependence of the age of production was found to be statistically not significant. On the other hand, pre-etching treatment using hot water and carbon dioxide with different etching times showed statistically significant effects on track area, track sensitivity, and roundness. It was concluded that there are simple methods to increase performance of nuclear track detectors, and that storage time is not a factor of concern.

Growth of Clostridium perfringens in Fish Fillets Packaged with a Controlled Carbon Dioxide Atmosphere at Abuse Temperatures

1996 ◽  
Vol 59 (7) ◽  
pp. 704-710 ◽  
Author(s):  
BON KIMURA ◽  
SHUSAKU KURODA ◽  
MASATADA MURAKAMI ◽  
TATEO FUJII
Keyword(s):  
Carbon Dioxide ◽  
Clostridium Perfringens ◽  
Storage Time ◽  
Health Hazard ◽  
Food Poisoning ◽  
Lag Phase ◽  
Carbon Dioxide Gas ◽  
Fish Fillets ◽  
Carbon Dioxide Atmosphere ◽  
Gas Atmosphere

The growth of Clostridium perfringens inoculated in fish fillets of jack mackerel subsequently packaged under a controlled carbon dioxide gas atmosphere (40% CO2, 60% N2) was investigated at marginal growth (15°C) and stimulative ambient (30°C) handling temperatures. The fish fillets were inoculated with C. perfringens, packaged either with air or the modified controlled carbon dioxide atmosphere and stored at 15°C and 30°C. No increase in the C. perfringens population in the fish was noted regardless of the type of packaging at 15°C in 3 days storage time, when all samples were spoiled. C. perfringens rapidly increased in the abuse temperature (30°C) after a 2- to 4-h lag phase regardless of the package type, but growth was significantly more stimulated under the controlled carbon dioxide gas atmosphere within 6 h of storage time. When fish fillets inoculated with C. perfringens were stored at 5°C for 24 h before being held at 30°C for 6 h, C. perfringens did not grow during the abuse-temperature storage. This suggests a reduction of a health hazard risk by the organism when the distribution temperature of the fish fillets is strictly controlled below 5°C. However, the combination of two temperature-abuse events during distribution and consumer handling may lead to a higher food-poisoning risk by the organism in controlled CO2 modified atmosphere-packaged fish compared to air-packaged fish. Product control of the initial contamination of organisms at low levels during raw fish processing will prevent food poisoning

scholarly journals 3-D imaging of particle tracks in solid state nuclear track detectors

2010 ◽  
Vol 10 (5) ◽  
pp. 1033-1036 ◽  
Author(s):  
D. Wertheim ◽  
G. Gillmore ◽  
L. Brown ◽  
N. Petford
Keyword(s):  
Lung Cancer ◽  
Solid State ◽  
Laser Scanning ◽  
Confocal Laser Scanning Microscope ◽  
Alpha Particles ◽  
Confocal Laser ◽  
Scanning Microscope ◽  
Nuclear Track Detectors ◽  
The Uk ◽  
Cr 39 Detectors

Abstract. It has been suggested that 3 to 5% of total lung cancer deaths in the UK may be associated with elevated radon concentration. Radon gas levels can be assessed using CR-39 plastic detectors which are often assessed by 2-D image analysis of surface images. 3-D analysis has the potential to provide information relating to the angle at which alpha particles impinge on the detector. In this study we used a "LEXT" OLS3100 confocal laser scanning microscope (Olympus Corporation, Tokyo, Japan) to image tracks on five CR-39 detectors. We were able to identify several patterns of single and coalescing tracks from 3-D visualisation. Thus this method may provide a means of detailed 3-D analysis of Solid State Nuclear Track Detectors.

Commodity Heating Medium and Mexican Fruit Fly Mortality

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 533e-533
Author(s):  
Krista C. Shellie
Keyword(s):  
Carbon Dioxide ◽  
Variable Temperature ◽  
Larval Mortality ◽  
Fruit Fly ◽  
Hot Water ◽  
Water Bath ◽  
Controlled Atmosphere ◽  
Mexican Fruit Fly ◽  
Temperature Water ◽  
Heating Medium

The objective of this research was to investigate whether the medium used to transfer heat to a commodity influenced the mortality of Mexican fruit fly larvae. A similar 2-h heat dose was delivered to grapefruit via immersion in a variable temperature water bath or via exposure to a rapidly circulating gas. The concentration of oxygen and carbon dioxide inside the grapefruit was analyzed at 30-min intervals and grapefruit center temperatures recorded every 60 s during heating. The mortality of larvae located inside grapefruit during heating in a controlled atmosphere or in hot water was significantly higher than that of larvae located inside grapefruit heated in air. The internal atmosphere of grapefruit heated in a controlled atmosphere or in hot water contained significantly higher levels of carbon dioxide and lower levels of oxygen than grapefruit heated in air. Larval mortality was compared after larvae were heated in media by rapidly circulating air or by an atmosphere containing 4 kPa of oxygen and 18 kPa of carbon dioxide to evaluate whether the altered atmosphere or a heat-induced fruit metabolite was responsible for enhanced mortality. The significantly higher mortality of larvae heated in media in the presence of an altered atmosphere suggested that the altered atmosphere enhanced larval mortality. Results from this research suggest that reducing oxygen and or increasing the level of carbon dioxide during heating can enhance mortality of the Mexican fruit fly and potentially reduce the heat dose required for quarantine security.

Thermodynamic Studies of Iron Carbonate Solubility in Aqueous Monoethylene Glycol Mixtures and CO2 Atmosphere

2016 ◽  
Vol 830 ◽  
pp. 134-138 ◽  
Author(s):  
Camila Senna Figueiredo ◽  
Jailton Ferreira do Nascimento ◽  
Rony Oliveira de Sant'ana ◽  
Deborah Cordeiro de Andrade ◽  
Zaniel Souto Dantas Procópio ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Natural Gas ◽  
High Capacity ◽  
Gas Production ◽  
Aqueous Mixtures ◽  
Iron Carbonate ◽  
Low Viscosity ◽  
Carbon Dioxide Atmosphere ◽  
Equilibrium Data ◽  
Monoethylene Glycol

Monoethylene glycol (MEG) is being widely applied as thermodynamic inhibitor to avoid formation of natural gas hydrates. High hydrophilicity, low toxicity, low viscosity, low solubility in liquid hydrocarbons and high capacity of dissolving salts are advantageous for the use of MEG in the natural gas production. In addition, MEG recovery can be easily achieved considering its low volatility in relation to water, which makes the process economical and environmentally feasible. The reuse of MEG is being theme of research and phase equilibrium data for the involved species are required. In this work, a experimental procedure to synthetize iron carbonate and, afterwards, determine its solubility in aqueous mixtures of MEG in the presence of carbon dioxide atmosphere have been developed. Furthermore, a series of solubility data has been measured. This work presents a worthy contribution to the description of iron carbonate aqueous solubilities in the presence of MEG and carbon dioxide, regarding the instability of the salt to respect of oxidation. Subsequently, the knowledge of the behavior of the iron carbonate solubilities is useful for the industrial unities of production of natural gas and recovery of MEG.

scholarly journals The expansion of TRIAC to TRIACII code for track measurements from SSNT detectors

2020 ◽  
Vol 15 ◽  
pp. 180
Author(s):  
D. L. Patiris ◽  
K. Blekas ◽  
K. G. Ioannides
Keyword(s):  
Image Analysis ◽  
Solid State ◽  
Hough Transform ◽  
Alpha Particles ◽  
Mode I ◽  
Mode Ii ◽  
Mean Intensity ◽  
Nuclear Track Detectors ◽  
Analysis Tools ◽  
Energy Discrimination

The expansion of TRIAC to TRIACII code will be described. Both codes have been developed for recognition and parameters measurements of particles’ tracks from images of Solid State Nuclear Track Detectors. While the first program considers the tracks as circles, TRIACII code, using image analysis tools, counts the number of tracks and depending on the current working mode classifies them according to their radii (Mode I- circular tracks) or their axis (Mode II- elliptical tracks), their mean intensity value (brightness) and their orientation. Hough transform techniques are used for the estimation of tracks’ number and their parameters which are able to give results even for overlapping tracks. The new program has been used for radon’s progeny behavior and alpha particles’ energy discrimination.

The Alpha Particle Doses Received by Students and Staff in Twenty Schools in the North of Hebron Region - Palestine

2021 ◽  
Vol 14 (4) ◽  
pp. 309-316
Keyword(s):  
Effective Dose ◽  
Radon Concentration ◽  
Annual Effective Dose ◽  
Indoor Radon ◽  
Alpha Particles ◽  
Indoor Radon Concentration ◽  
The North ◽  
Cr 39 Detectors ◽  
Average Effective Dose ◽  
Radon Concentrations

Abstract: The aim of the current study was to measure indoor radon concentration levels and its resulting doses received by the students and staff in schools of the directorate of education in the north of Hebron region- Palestine, during the summer months from June to September (2018), using CR-39 detectors. In this study, a total of 567 CR-39-based radon detectors were installed in the selected schools. The average radon concentrations were found to be 90.0, 66.5 and 58.0 Bqm-3 in Halhul, Beit Umar and Alarrub camp schools, respectively. Based on the measured indoor radon data, the overall average effective dose for the studied area was found to be 0.31 mSvy-1. Reported values for radon concentrations and corresponding doses are lower than ICRP recommended limits for workplaces. The results show no significant radiological risk for the pupils and staff in the schools under investigation. Consequently, the health hazards related to radiation are expected to be negligible. Keywords: Radon concentration, Alpha particles, Annual effective dose, Schools. PACs: 29.40.−n.

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