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X-rays, X-ray tube and X-ray Circuit
Published in Ken Holmes, Marcus Elkington, Phil Harris, Clark's Essential Physics in Imaging for Radiographers, 2021
The intensity of the beam represents the quantity of radiation produced at a given energy and the maximum beam intensity for the full range of energies which make up the heterogeneous beam is given by the curve on the Bremsstrahlung graph. Radiation intensity is a measure of the number of photons in a beam of a given cross-sectional area. The height of the Bremsstrahlung curve will be directly proportional to the intensity of the X-ray beam. This can be referred to as the size of the curve.
Ionizing Radiation as an Essential Agent
Published in T. D. Luckey, Radiation Hormesis, 2020
Cosmic radiation intensity in the ANL subambient radiation chamber was about 3% that of the surface laboratory for energies <1 MeV and about 8% between 1 and 3 MeV (Figure 8.5). The 1-cm-thick lead box with a cadmium sheet and copper-foil-covered interior was placed in an incubator inside a room which had 21-cm, old steel walls, floor, door, and roof; this was in a building with 90 cm of specially dense concrete under 3.5 m earth.
Physics of Radiation Biology
Published in Kedar N. Prasad, Handbook of RADIOBIOLOGY, 2020
It is possible to estimate the radiation exposure for γ-rays with energy between 0.3 and 3.0 MeV by the following equation: R = 6 CiE, where R is the exposure rate (R/h at 1 ft), Ci is the number of curies, and E is the average γ energy per disintegration (MeV). If γ energies greater than one are emitted per disintegration, this should be taken into consideration. For example, 60Co has a γ energy of 1.2 and 1.3 MeV; therefore, the E value for 60Co would be 1.2 + 1.3 = 2.5 MeV. Another relationship that can be used with the γ source is the inverse square law, which states that the radiation intensity varies inversely as the square of the distance from the source.
1,25-Dihydroxvitamin D3 attenuates the damage of human immortalised keratinocytes caused by Ultraviolet-B
Published in Cutaneous and Ocular Toxicology, 2023
Pingwei Wang, Dongge Liu, Jiajing Cui, Shuqi Yan, Yujun Liang, Qianqian Chen, Yanping Liu, Shuping Ren, Peng Chen
The HaCaT cells were plated in a 96-well plate with each well of 5 × 104 cells and cultured for 24h, aspirate the old culture solution, add PBS to wash the cells two times, add 20 μl of PBS to each well, move the cells to the UV lamp, open the lid of the 96-well plate, and then the cells were irradiated with UVB at the intensity of 5, 10, 20, 25, 30, 35, 40, 45 mJ/cm2, each intensity triple wells. Each different radiation dose is separately set with a 96-well plate for radiation to prevent mutual interference between different radiation dose groups. After irradiation, the cells were washed with PBS, then the cells were cultured in DMEM, 10 μL CCK-8 was added to the cells and incubated for 1h at 37 °C. The absorbance was determined at 450 nm wavelength. The viability of cells was calculated and the intensity of UVB was selected for the irradiation of the cells. (According to the calculation formula: radiation dose = radiation intensity × irradiation time, set the irradiation intensity to 220μw/cm2, according to 1 J = 2.778 × 10−7×kw × h. The irradiation time can be calculated for different UVB irradiation dose groups.)
Evaluating the potential severity of biogas toxic release, fire and explosion: consequence modeling of biogas dispersion in a large urban treatment plant
Published in International Journal of Occupational Safety and Ergonomics, 2023
Ahmad Soltanzadeh, Mohsen Mahdinia, Hamedeh Golmohammadpour, Reza Pourbabaki, Mostafa Mohammad-Ghasemi, Mohsen Sadeghi-Yarandi
Due to the ignition and explosion properties of methane gas, which constitutes more than 70% of biogas, the study of the effects of ignition and explosion has great importance. Examination of the affected distances due to fireball radiation intensity in scenario no. 1 revealed that the occurrence of fire in winter is more dangerous so that up to 217.24 and 91.56 m from the reservoir in the wind direction are placed in the first and second radiation levels, respectively, which is very dangerous and will cause serious damage to people and equipment. Examination of the distances affected by the jet fire radiation intensity also showed that the occurrence of fire in winter is more dangerous so that up to distances of 43.29, 40.61 and 38.83 m from the reservoir in the wind direction are located in the first, second and third radiation levels, respectively, which is very dangerous and can cause the immediate death of people and severe damage to equipment (Figure 7 and Table 7). In the event of a fireball, people will be affected for longer distances. However, the occurrence of jet fire is more dangerous, so that many people can be exposed to the third level of radiation (37.5 kW m−2). The results of previous studies have also revealed that the types of fires caused by biogas leakage can be referred to as flash fire, fireball and jet fires, and that the highest amounts of radiation and death are related to jet fire and fireball [25].
A review of the impact on the ecosystem after ionizing irradiation: wildlife population
Published in International Journal of Radiation Biology, 2022
Georgetta Cannon, Juliann G. Kiang
Radiation intensity in both Chernobyl and Fukushima has decreased with time. Under these conditions, organisms may evolve ways of surviving the radiation stress, also called adapting. Bonisoli-Alquati and colleagues (Bonisoli-Alquati et al. 2018) captured grasshoppers (Chorthippus albomarginatus) in the Chernobyl exclusion zone and raised their offspring in a common garden. They found that offspring that matured quicker than average grasshoppers contained more DNA damage. Faster growth rates cause elevated oxidative stress and subsequent injury, but the grasshoppers may gain time to reach adulthood and to reproduce before the radiation released from the environment kills them. The result suggests the presence of an adaption by maintaining the population at the expense of more DNA damage to the individual.