Cosmic rays (CRs) data observed through four neutron monitors and one muon telescope are used to study the solar diurnal variation (DV) from 1953 to 2010. The median primary rigidity of response, ...(Rm), for these detectors encompasses the range 16 ≤ Rm ≤ 60 GV of the galactic CRs spectrum. The phase angle observed with the lower rigidity station depends strongly on the solar magnetic field polarity reversal due to drift effect. However, the higher rigidity stations show an 11 year cycle. This cycle is evident in the shape of the cross‐correlation functions (CCFs) between the phase angle and the interplanetary magnetic field (IMF) parameters due to diffusion of galactic CRs by the IMF. The amplitude of the DV, IMF magnitude, and solar activity are larger, and the phase angle is later in hours for qA < 0 than for qA > 0. In addition, the amplitude is well correlated with the IMF magnitude. The amplitudes observed by the lower rigidity station peaks 2 years after the IMF magnitude reach maximum for qA < 0. The diurnal amplitude reaches minimum 2–3 years after the solar wind speed peak due to outward convection by solar wind along the helioequator. The phase angle of the higher rigidity station shifts toward the earliest hours, 2 years after the wind speed peaks for qA > 0. This shift is due to outward convection by solar wind that increases the radial component of the DV more than the East‐West component.
Key Points
Diurnal Variation
Solar Polarity Dependence
diffusion of galactic cosmic rays
Abstract
In this work, morphological and attenuation parameters of gamma ray protection were studied. Dimethyl polysiloxane (Silicon Rubber) Mixed with micro-size and nano-size lead oxide particles ...at different weight percentage were prepared. The morphological structure of PbO/SR composites was investigated by SEM test, according to SEM images the nano PbO particles are more uniform micro PbO particles. The radiation attenuation test was carried out using 3ʺ × 3ʺ NaI (TI) detector for (Am-241), (Cs-137), (Co-60), (Ba-133), and (Eu-152). The effect on attenuation property of SR-PbO shown that the increase of PbO filler significantly increases the linear attenuation coefficient and improve the other radiation protection parameters especially at low gamma energy. It's found that a significant agreement between the experimental result and theoretical result from Xcom program. In this study it's found matrix filled with nano-PbO have higher gamma shielding ability compared to micro-PbO matrix at the same filler concentration. It can say that SR-nano PbO has a higher radiation protection than SR-micro PbO compositions.
Reinforced polymer composites are a recent type of advanced shielding material that has been studied experimentally and theoretically. This work described the protection properties of silicon rubber ...filled with nano and micro tin oxide (II). These shielding materials are evaluated by parameters such as mass attenuation coefficient, linear attenuation coefficient, mean free path, effective atomic number, and buildup factor. The morphology and mechanical properties of silicon rubber, which is reinforced with tin oxide (II) particles in terms of weight fraction and size, have been studied. The results explain that the mass attenuation coefficient increases as tin oxide (II) concentration increases at a particular photon energy. It was found that the shielding properties of nano tin oxide (II) composites are more effective than micro tin oxide (II) composites against gamma rays. The effective atomic number values increase by increasing tin oxide (II) and so on equivalent atomic number. On the other hand, increasing tin oxide (II) weight fraction led to an increase in buildup factor maximum, which proved that tin oxide (II) concentration has significant effectiveness in radiation protection.
Abstract Radioactive iodine isotopes especially 131 I are used for diagnosis and treatment of different types of cancer diseases. Due to the leak of radioactive iodine into the patient’s urine in ...turn, the wastewater would be contaminated, so it is worth preparing a novel adsorption green material to remove the radioactive iodine from wastewater efficiently. The removal of 127 I and 131 I contaminants from aqueous solution is a problem of interest. Therefore, this work presents a new study for removing the stable iodine 127 I − and radioactive iodine 131 I from aqueous solutions by using the novel nano adsorbent (Nano ZnO/MWCNTs) which is synthesized by the arc discharge method. It is an economic method for treating contaminated water from undesired dissolved iodine isotopes. The optimal conditions for maximum removal are (5 mg/100 ml) as optimum dose with shacking (200 rpm) for contact time of (60 min), at (25 °C) in an acidic medium of (pH = 5). After the adsorption process, the solution is filtrated and the residual iodide ( 127 I − ) is measured at a maximum UV wavelength absorbance of 225 nm. The maximum adsorption capacity is (15.25 mg/g); therefore the prepared nano adsorbent (Nano ZnO/MWCNTs) is suitable for treating polluted water from low iodide concentrations. The adsorption mechanism of 127 I − on to the surface of (Nano ZnO/MWCNTs) is multilayer physical adsorption according to Freundlich isotherm model and obeys the Pseudo-first order kinetic model. According to Temkin isotherm model the adsorption is exothermic. The removal efficiency of Nano ZnO/MWCNTs for stable iodine ( 127 I − ) from aqueous solutions has reached 97.23%, 89.75%, and 64.78% in case of initial concentrations; 0.1843 ppm, 0.5014 ppm and 1.0331 ppm, respectively. For the prepared radio iodine ( 131 I − ) solution of radioactivity (20 µCi), the dose of nano adsorbent was (10 mg/100 ml) and the contact time was (60 min) at (pH = 5) with shacking (200 rpm) at (25 °C). The filtration process was done by using a syringe filter of a pore size (450 nm) after 2 days to equilibrate. The removal efficiency reached (34.16%) after the first cycle of treatment and the percentage of residual radio iodine was (65.86%). The removal efficiency reached (94.76%) after five cycles of treatment and the percentage of residual radio iodine was (5.24%). This last percentage was less than (42.15%) which produces due to the natural decay during 10 days.
Biogas is a sustainable, renewable energy source generated from organic waste degradation during anaerobic digestion (AD). AD is applied for treating different types of wastewater, mostly containing ...high organic load. However, AD practice is still limited due to the low quality of the produced biogas. Upgrading biogas to natural gas quality (>90% CH
) is essential for broad applications. Here, an innovative bio-electrochemically assisted AD process was developed, combining wastewater treatment and biogas upgrading. This process was based on a microbial electrolysis cell (MEC) that produced hydrogen from wastewater at a relatively high efficiency, followed by high-rate anaerobic systems for completing biodegradation of organic matter and an in situ bio-methanation process. Results showed that CH
production yield was substantially improved upon coupling of the MEC with the AD system. Interestingly, CH
production yield increase was most notable once circulation between AD and MEC was applied, while current density was not markedly affected by the circulation rates. The microbial community analysis confirmed that the MEC enhanced hydrogen production, leading to the enrichment of hydrogenotrophic methanogens. Thus, directing soluble hydrogen from the MEC to AD is plausible, and has great potential for biogas upgrading, avoiding the need for direct hydrogen harvesting.
Spectral analysis of neutron monitors and muon telescope daily averages counts shows a significant higher harmonic (∼9 day) of the 27 day variation of galactic cosmic rays (CRs). This ...quasiperiodicity is also present in the time series of daily averages of the product of interplanetary magnetic field magnitude and the square of solar wind speed (BV2). The wavelet spectrum density of the third harmonic of the 27 day variation of CRs is weakly correlated with the quantity BV2. This result reflects the coupling between galactic CR modulation and interplanetary parameters.
Key Points
Nine day periodicity is evident in the spectra of galactic cosmic rays
Nine day periodicity is also evident in the spectra of the quantity BV2
Coupling between galactic cosmic ray modulation and interplanetary parameters
ABSTRACT The analysis of cosmic ray intensity variation seen by muon detectors at Earth's surface can help us to understand astrophysical, solar, interplanetary and geomagnetic phenomena. However, ...before comparing cosmic ray intensity variations with extraterrestrial phenomena, it is necessary to take into account atmospheric effects such as the temperature effect. In this work, we analyzed this effect on the Global Muon Detector Network (GMDN), which is composed of four ground-based detectors, two in the northern hemisphere and two in the southern hemisphere. In general, we found a higher temperature influence on detectors located in the northern hemisphere. Besides that, we noticed that the seasonal temperature variation observed at the ground and at the altitude of maximum muon production are in antiphase for all GMDN locations (low-latitude regions). In this way, contrary to what is expected in high-latitude regions, the ground muon intensity decrease occurring during summertime would be related to both parts of the temperature effect (the negative and the positive). We analyzed several methods to describe the temperature effect on cosmic ray intensity. We found that the mass weighted method is the one that best reproduces the seasonal cosmic ray variation observed by the GMDN detectors and allows the highest correlation with long-term variation of the cosmic ray intensity seen by neutron monitors.
Abstract
We analyze the cosmic-ray variations during a significant Forbush decrease observed with worldwide networks of ground-based neutron monitors and muon detectors during 2021 November 3–5. ...Utilizing the difference between primary cosmic-ray rigidities monitored by neutron monitors and muon detectors, we deduce the rigidity spectra of the cosmic-ray density (or omnidirectional intensity) and the first- and second-order anisotropies separately for each hour of data. A clear two-step decrease is seen in the cosmic-ray density with the first ∼2% decrease after the interplanetary shock arrival followed by the second ∼5% decrease inside the magnetic flux rope (MFR) at 15 GV. Most strikingly, a large bidirectional streaming along the magnetic field is observed in the MFR with a peak amplitude of ∼5% at 15 GV, which is comparable to the total density decrease inside the MFR. The bidirectional streaming could be explained by adiabatic deceleration and/or focusing in the expanding MFR, which have stronger effects for pitch angles near 90°, or by selective entry of GCRs along a leg of the MFR. The peak anisotropy and density depression in the flux rope both decrease with increasing rigidity. The spectra vary dynamically, indicating that the temporal variations of density and anisotropy appear different in neutron monitor and muon detector data.
Cosmic rays are charged particles whose flux observed at Earth shows temporal variations related to space weather phenomena and may be an important tool to study them. The cosmic ray intensity ...recorded with ground‐based detectors also shows temporal variations arising from atmospheric variations. In the case of muon detectors, the main atmospheric effects are related to pressure and temperature changes. In this work, we analyze both effects using data recorded by the Global Muon Detector Network, consisting of four multidirectional muon detectors at different locations, in the period between 2007 and 2016. For each Global Muon Detector Network directional channel, we obtain coefficients that describe the pressure and temperature effects. We then analyze how these coefficients can be related to the geomagnetic cutoff rigidity and zenith angle associated with cosmic ray particles observed by each channel. In the pressure effect analysis, we found that the observed barometric coefficients show a very clear logarithmic correlation with the cutoff rigidity divided by the zenith angle cosine. On the other hand, the temperature coefficients show a good logarithmic correlation with the product of the cutoff and zenith angle cosine after adding a term proportional to the sine of geographical latitude of the observation site. This additional term implies that the temperature effect measured in the Northern Hemisphere detectors is stronger than that observed in the Southern Hemisphere. The physical origin of this term and of the good correlations found in this analysis should be studied in detail in future works.
Key Points
Pressure and temperature effects observed by ground muon detectors was experimentally analyzed inrelation to cutoff rigidity and zenith angle
The best correlation was found when considering product between cutoff rigidity and zenith angle secant (pressure) or cosine (temperature)
The temperature effect only shows a global trend if a relationship with the sine of each detector's geographic latitude is included
•High dose per fraction regimens induce the expression of ferroptosis markers more than low dose per fraction regimen and single dose of ionizing radiation and subsequently enhances tumor cell death ...through ferroptosis.•Ionizing radiation at all doses induces pyroptotic cell death through cleavage of GSDMD protein which results in the generation of cellular membrane pores and release of GSDMD-CT, IL-1β, and IL-18 from tumor tissues to circulation.•Ferroptosis and pyroptosis as new cell death mechanisms can be induced in cancer cells by ionizing radiation especially at high dose per fraction regimens and presenting an alternative anti-cancer strategy.
Objective: Our objective was to explore the effect of different fractionation schedule on ferroptosis and pyroptosis biomarkers as new cell death mechanisms induced by IR.
Materials and Methods: This study included 40 tumor bearing mice divided into: Group I: Includes 8 untreated tumor-bearing mice. Group II: Includes 8 tumor bearing mice exposed to single dose 6 Gy of IR. Group III: Includes 8 tumor bearing mice exposed to 12 Gy in 2 fractions (2 × 6 Gy) of IR. Group IV: Includes 8 tumor bearing mice exposed to 12 Gy in 3 fractions (3 × 4 Gy) of IR. Group V: Includes 8 tumor bearing mice exposed to 8 Gy in 4 fractions (4 × 2 Gy) of IR. IL-1β, IL-18, and GSDMD-CT levels were assessed by ELISA. PTGS2 and ACSL4 expression were assessed by RT-PCR.
Results: (2 × 6 Gy) group showed the highest ACSL4 expression followed by (3 × 4 Gy), then (4 × 2 Gy) and finally 6 Gy. (2 × 6 Gy) group resulted in the highest PTGS2 expression followed by (3 × 4 Gy), then 6 Gy, and finally (4 × 2 Gy). MDA significantly increased at (2 × 6 Gy), (3 × 4 Gy), and 6 Gy groups and insignificantly increased at (4 × 2 Gy) group. Iron significantly increased at (2 × 6 Gy), (3 × 4 Gy), and (4 × 2 Gy) groups and insignificantly at 6 Gy. Glutathione was significantly decreased at (2 × 6 Gy), (3 × 4 Gy), and (4 × 2 Gy) groups and insignificantly at 6 Gy. GSDMD-CT, IL-1β, and IL-18 levels significantly reduced in tumor tissues after exposure to IR at all doses.
Conclusion: High dose per fraction regimens induce the expression of ferroptosis markers more than low dose per fraction regimen and single dose of IR. IR at all doses induces pyroptotic cell death.
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