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2022 ◽  
Vol 12 (2) ◽  
pp. 637
Author(s):  
Entesar Almogait ◽  
Aljawhara H. Almuqrin ◽  
Nourah Alhammad ◽  
M. I. Sayyed

A sensitization procedure is used to enhance the thermoluminescence (TL) sensitivity of phyllite to emit radiation. Phyllite is a type of foliated metamorphic rock made from slate. This study examines naturally grown phyllite rock, which had not been previously studied. Using a Thermo 3500 manual reader, the TL sensitivity of phyllite as a function of dosage was measured. The doses required to perform this study were administered using a 60Co source. The statistical regression test of the data had a significance level of p < 0.05. The study also included thermal and pre-dose effects. Using the sensitization procedure, the nonlinearity in TL dose–response was removed, and the sensitivity was increased 44 times that of its original value. The fading study showed a dependence on the test dose. According to the obtained results, the combination of linear dose–response and high sensitivity to gamma radiation makes phyllite an important rock for dating and retrospective dosimetry.


2021 ◽  
Vol 14 (12) ◽  
pp. 7497-7526
Author(s):  
Alan J. Geer ◽  
Peter Bauer ◽  
Katrin Lonitz ◽  
Vasileios Barlakas ◽  
Patrick Eriksson ◽  
...  

Abstract. Satellite observations of radiation in the microwave and sub-millimetre spectral regions (broadly from 1 to 1000 GHz) can have strong sensitivity to cloud and precipitation particles in the atmosphere. These particles (known as hydrometeors) scatter, absorb, and emit radiation according to their mass, composition, shape, internal structure, and orientation. Hence, microwave and sub-millimetre observations have applications including weather forecasting, geophysical retrievals and model validation. To simulate these observations requires a scattering-capable radiative transfer model and an estimate of the bulk optical properties of the hydrometeors. This article describes the module used to integrate single-particle optical properties over a particle size distribution (PSD) to provide bulk optical properties for the Radiative Transfer for TOVS microwave and sub-millimetre scattering code, RTTOV-SCATT, a widely used fast model. Bulk optical properties can be derived from a range of particle models including Mie spheres (liquid and frozen) and non-spherical ice habits from the Liu and Atmospheric Radiative Transfer Simulator (ARTS) databases, which include pristine crystals, aggregates, and hail. The effects of different PSD and particle options on simulated brightness temperatures are explored, based on an analytical two-stream solution for a homogeneous cloud slab. The hydrometeor scattering “spectrum” below 1000 GHz is described, along with its sensitivities to particle composition (liquid or ice), size and shape. The optical behaviour of frozen particles changes in the frequencies above 200 GHz, moving towards an optically thick and emission-dominated regime more familiar from the infrared. This region is little explored but will soon be covered by the Ice Cloud Imager (ICI).


2021 ◽  
Vol 7 (3) ◽  
pp. 99-102
Author(s):  
Kajol M Talreja

Nuclear medicine is the discipline of medicine that deals with the use of radionuclides in research, diagnosis, and treatment. It works on molecular & functional level and uses radiopharmaceuticals in its procedure helping in detection of lesions before morphologic change is evident. Radiopharmaceuticals also known as Radionuclides/ Radioisotopes are unstable atoms of a chemical element, actively emit radiation. These emitted radiations are absorbed by photomultiplier tube and reconstructed by a computer system followed by display of an image. The rationale of writing this article is to understand about Nuclear Medicine and its applications in oral diseases.


2021 ◽  
Vol 11 (5) ◽  
pp. 7720-7729
Author(s):  
D. Vatamanu ◽  
S. Miclaus

The growing evidence of increased magnetite nanoparticles (both endo- and exo-genic) in the human brain raises the importance of assessing the entire power deposition when electromagnetic waves at GHz frequencies propagate in such tissues. This frequency range corresponds to many popular portable communication devices that emit radiation close to a human's head. At these frequencies, the current dosimetric numerical codes can not accurately compute the magnetic losses part. This is due to the lack of an implemented computational algorithm based on solving the coupled Maxwell and Landau-Lifshitz-Gilbert equations, in the case of magneto-dielectrics, considering eddy currents losses and specific properties of magnetic sub-millimetric particles. This paper focuses on analyzing the limits and the inconsistencies when using commercial dosimetric numerical software to analyze the total absorbed power in brain models having ferrimagnetic content and being exposed to 3.5GHz electromagnetic waves. Magnetic losses computed using Polder’s permeability tensor as constitutive relation lead to unreliable results. However, using such software can provide a preliminary view of the electromagnetic impact of ultra- and super-high frequencies on magnetic-dielectric tissues.


Nature ◽  
2021 ◽  
Vol 597 (7874) ◽  
pp. 41-44
Author(s):  
C. C. Espaillat ◽  
C. E. Robinson ◽  
M. M. Romanova ◽  
T. Thanathibodee ◽  
J. Wendeborn ◽  
...  

AbstractMagnetospheric accretion models predict that matter from protoplanetary disks accretes onto stars via funnel flows, which follow stellar magnetic field lines and shock on the stellar surfaces1–3, leaving hot spots with density gradients4–6. Previous work has provided observational evidence of varying density in hot spots7, but these observations were not sensitive to the radial density distribution. Attempts have been made to measure this distribution using X-ray observations8–10; however, X-ray emission traces only a fraction of the hot spot11,12 and also coronal emission13,14. Here we report periodic ultraviolet and optical light curves of the accreting star GM Aurigae, which have a time lag of about one day between their peaks. The periodicity arises because the source of the ultraviolet and optical emission moves into and out of view as it rotates along with the star. The time lag indicates a difference in the spatial distribution of ultraviolet and optical brightness over the stellar surface. Within the framework of a magnetospheric accretion model, this finding indicates the presence of a radial density gradient in a hot spot on the stellar surface, because regions of the hot spot with different densities have different temperatures and therefore emit radiation at different wavelengths.


2021 ◽  
Author(s):  
Alan Jon Geer ◽  
Peter Bauer ◽  
Katrin Lonitz ◽  
Vasileios Barlakas ◽  
Patrick Eriksson ◽  
...  

Abstract. Satellite observations of radiation in the microwave and sub-mm spectral regions (broadly from 1 to 1000 GHz) can have strong sensitivity to cloud and precipitation particles in the atmosphere. These particles (known as hydrometeors) scatter, absorb and emit radiation according to their mass, composition, shape, internal structure, and orientation. Hence, microwave and sub-mm observations have applications including weather forecasting, geophysical retrievals and model validation. To simulate these observations requires a scattering-capable radiative transfer model and an estimate of the bulk optical properties of the hydrometeors. This article describes the module used to integrate single-particle optical properties over a particle size distribution (PSD) to provide bulk optical properties for the Radiative Transfer for TOVS microwave and sub-mm scattering code, RTTOV-SCATT, a widely-used fast model. Bulk optical properties can be derived from a range of particle models including Mie spheres (liquid and frozen) and non-spherical ice habits from the Liu and Atmospheric Radiative Transfer Simulator (ARTS) databases, which include pristine crystals, aggregates and hail. The effects of different PSD and particle options on simulated brightness temperatures are explored, based on an analytical two-stream solution for a homogeneous cloud slab. The hydrometeor scattering "spectrum" below 1000 GHz is described, along with its sensitivities to particle composition (liquid or ice), size and shape. The optical behaviour of frozen particles changes in the frequencies above 200 GHz, moving towards an optically thick and emission-dominated regime more familiar from the infrared. This region is previously little explored but will soon be covered by the Ice Cloud Imager (ICI).


KOMPUTEK ◽  
2021 ◽  
Vol 5 (1) ◽  
pp. 42
Author(s):  
Andy Nugroho Prio Utomo ◽  
Edy Kurniawan ◽  
Muh Muhsin

Television is an electronic device which now the majority is owned by all Indonesians. Besides the use of this electronic device, there is a negative impact or thing that is contained in this electronic device. When watching television, eyes often experience tired and dry eyes, this is caused by television monitors that emit radiation rays and cause several eye problems. The radiation beam emitted from each television differs depending on the size of the monitor. This has been proven by tests that have been carried out by related institutions that the distance to watch television for each monitor is different. "The eye has the most important role for the development of human intelligence". Therefore a tool was designed from the problems that arise which will set the ideal distance for watching television using the PIR sensor to determine the distance of the audience from the television which will be forwarded to Arduino UNO as data processing, the output of the tool is in the form of LED, Buzzer and executed by Rellay as Automatic shutdown where the television will be turned off automatically when the audience enters a distance of less than 3 meters and within 1 minute with the LCD indicator displaying text data in the form of "Danger" and the television will not be turned off automatically if the viewing distance is more than 3 meters and the LCD will display text data in the form of "SAFE".


Gels ◽  
2021 ◽  
Vol 7 (1) ◽  
pp. 19
Author(s):  
Girishma Grover ◽  
Richard G. Weiss

We present a brief review of some important conceptual and practical aspects for the design and properties of molecular luminescent gelators and their gels. Topics considered include structural and dynamic aspects of the gels, including factors important to their ability to emit radiation from electronically excited states.


2021 ◽  
pp. 246-246
Author(s):  
Andreas Raptis

We study the effects of the thermal radiation and an induced magnetic field on the flow over a black isothermal plate for an optically thin gray fluid. The flowing medium absorbs and emit radiation, but scattering is not included. Numerical solutions are obtained for different values of radiation parameter, Prandtl number, Grashof number and magnetic Prandtl number.


2020 ◽  
Vol 64 (11) ◽  
pp. 1939-1946
Author(s):  
Nam-Phong Nguyen ◽  
Stefan Behrens ◽  
Maximilian Brosda ◽  
Alexander Olowinsky ◽  
Arnold Gillner

Abstract The growing demands on the quality of plastic components and the trend towards miniaturisation are posing a great challenge on plastics processing technology. As many complex components can no longer be manufactured in a single step, joining processes such as laser transmission welding are gaining in importance. In classic laser transmission welding, the joining partners have different optical properties. The upper joining partner is transparent in the laser wavelength range, whilst the lower partner is absorbent due to the addition of absorber materials. In medical and biotechnological applications, the addition of absorber materials is often undesirable due to strict biocompatibility requirements. If, on the other hand, radiation sources are used which emit radiation in the area of the natural absorption of the plastic (λ = 1600–2000 nm), untreated transparent plastics can also be welded. In this work, a theoretical model will be presented to calculate the temperature distribution and progression during quasi-simultaneous welding using a thulium fibre laser (λ = 1940 nm). A sensitivity analysis is carried out to investigate the influence of different parameters on the heat affected zone (HAZ). The simulated HAZ is then compared with the HAZ from the experimental work.


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