Numerical calculation of passenger compartment cooling effect under the action of radiative cooling film based on MATLAB

Radiative cooling uses space cold source to cool the object, and the radiative cooling film made by using this principle can be applied to automobiles effectively to save the refrigeration resources of automobiles. However, due to the limitation of economy, time, space and other factors, it is difficult to carry out comprehensive research on the actual film-forming cooling effect. Based on the principle of passive radiative cooling, a set of simulation models is developed, which is applied to the selection of infrared radiation materials for automotive radiative cooling film and the study of the influence of environmental factors on the radiative cooling effect. SiO2 was finally selected as infrared radiation material. At the same time, the theoretical cooling temperature of the radiative cooling film applied to the passenger compartment of automobiles can reach 6.8°C under the conditions of 35°C ambient temperature, 0.99 atmospheric transmittance and 10 heat transfer coefficient, using SiO2 as infrared radiation material and PE as dispersion substrate. At the same time, the cooling effect of the radiative cooling film is positively correlated with the ambient temperature, atmospheric transmittance to some extent.

"Subacute" course of chronic radiation syndrome

Introduction. The use of ionizing radiation as a production factor in the late 1940s - early 1950s. began in the absence of a clear understanding of the permissible radiation doses for workers, as well as knowledge of diagnostic criteria and developed therapeutic measures for developing chronic radiation sickness (CRS). Since then, a great deal of experience has been accumulated in the diagnosis and treatment of CRS. Currently, there are no conditions at the workplace for chronic exposure of workers in doses exceeding the permissible ones. However, taking into account the constant expansion of the scope of using sources of ionizing radiation, it is necessary to remember about the possibility of CRS development due to prolonged exposure in case of violation of their storage or their loss. The study aimed to explore the formation of radiation bone marrow syndrome (RBS) due to chronic exposure in doses that exceed the maximum permissible, accumulated with different dose rates of radiation. Material and methods. We selected the medical records of 27 people (24 men and 3 women) who had RBS as a result of chronic professional gamma radiation exposure. The selection criteria were the diagnosis of grade II-III chronic radiation syndrome (CRS) in the presence of agranulocytosis or anemic syndrome in the period of the disease formation and, especially, in the development of myelodysplastic syndrome (MDS) or aplastic anemia in the period of the CRS consequences. Identified clinical and dosimetric CRS features of 27 patients exposed to chronic irradiation with a dose rate of 0.0002-0,009 Gy/h and the summary dose of 1.7 and 9.6 Gy, accumulated over a period of 6 to 96 months were compared the characteristics of 84 patients CRS exposed a lower dose rates (less than 0,0003 Gy/h) and 26 patients with acute radiation syndrome moderate (II) severity as a result of irradiation the dose rates of 0.14-3,7 Gy/h, total dose of 2 to 4 Gy. Results. The criteria of atypical subacute CRS course are identified: the rate of chronic radiation exposure - not less than 0.001-0.009 Gy/h with a summary dose of 1.7-9.6 Gy accumulated over a period of 6-96 months, the presence of agranulocytosis in the period of CRS formation and anemic syndrome in the periods of CRS formation and outcomes. These signs predict the development MDS in 60% of the patients in the period of the CRS consequences. Conclusion. Retrospective study determined that long-term human exposure to a dose rate of 0.001-0,009 Gy/h (0,005-0,05 Gy/day) and more in the accumulation of a summary dose of 1.7 and 9.6 Gy and duration of contact 6-96 months in 60% of cases can be expected development CRS with a subacute clinical course RBS. The main factor determining this feature of the course of RBS is the dose rate exceeding 0.001 Gy / h (2 Gy/year). In the subacute course of CRS, the early outcome in MDS is essentially deterministic. The development of agranulocytosis and anemic syndrome are typical signs of the subacute course of CRS.

MECHANISMS OF RADIATION DAMAGE AND DEVELOPMENT OF STRUCTURAL MATERIALS FOR OPERATING AND ADVANCED NUCLEAR REACTORS

Safety of nuclear reactor (NR) and economic of nuclear power are determined to high degree by structural materials. Study of reasons of change of physical-mechanical properties of materials and of their dimensional stability under irradiation; determination of operation life of elements of nuclear power energetic assemblies in different conditions, selection and development of prospective materials with high radiation resistance are the main objectives of radiation material science. In the presented paper, mechanisms of radiation damage of structural materials for nuclear power and problems of development of radiation-resistant materials for operating and advanced NR of new generation are examined.

LINE FOLLOWING ROBOT WITH HIGH RADIATION MATERIAL DETECTION CAPABILITY

Advancement in technology have led to a rapid development in the design and manufacturing of robots, enabling them to provide human capabilities without the inherent shortcoming associated with human capabilities; such as boredom, fear, inefficiency etc. A mobile robot that can sense and observe the line drawn on the floor is the Line Follower Robot. The direction is usually predefined and can be either visible on a white surface with a high contrast colour like a black line or invisible like a magnetic field. Hence, with its Infrared Ray (IR) sensors mounted under the robot, this sort of robot can feel the line. Then, the information is conveyed by specific transition buses to the processor. The processor will determine the right commands and then send them to the driver, and the line follower robot will then follow the direction. Therefore, this paper focuses on the design of a mobile line following robot for detecting the high radiation level of a sample farmland and display on a 7-segment display by the aid of sensors to navigate through grid. The mobile line following robot must move through the squares and detect the high radiation levels and at the end provides us with information on the number of squares and detected high radiation levels. The robot's area of operation is limited to six squares each of dimension 60cm×60 cm. Silver coloured square spots with dimensions of 5 cm by 5 cm made of foil paper are used to indicate a high radiation level

Experimental substantiation of scleral crosslinking

Purpose. To substantiate the efficacy and safety of scleral collagen cross-linking with riboflavin and ultraviolet radiation. Material and methods. The study was conducted on cadaver porcine eyes and rabbit eyes. Results. It has been experimentally proven that crosslinking with riboflavin / ultraviolet A leads to an increase in the biomechanical strength of the scleral tissue, changing its structure and leading to an increase in the packing density of collagen fibers and an increase in the diameter of collagen fibrils, which confirms the formation of additional cross-links between scleral macromolecules. The absence of any pathological changes in the fibers of the fibrous membrane of the eye was established. The permeability of scleral tissue for ultraviolet radiation of the A range was determined. Based on the data obtained, a formula was proposed for calculating the threshold value of the intensity of ultraviolet radiation during the SCXL procedure. Using the methods of light microscopy, electroretinography and optical coherence tomography, it was revealed that SCXL with riboflavin / ultraviolet A under the studied parameters is safe for the structures of the eye (cornea, retina and optic nerve). A gentle technology for photopolymerization of the sclera with the use of the “UFalink S” device has been developed, the advantage of which is the ability to carry out ultraviolet irradiation in hard-to-reach areas of the eyeball. At the same time, an effective increase in the biomechanical strength characteristics of the scleral tissue was proved and the absence of a damaging effect on the structures of the eye was demonstrated. Conclusion. A clinical study of the scleral crosslinking procedure with riboflavin / ultraviolet A with the proposed parameters: irradiance of 3 mW / cm², irradiation time 30 minutes and preliminary saturation of the sclera with 0.1% aqueous solution of riboflavin for 20 minutes, which in experiments have shown their effectiveness and safety, is recommended. During the procedure, it is recommended to use a water-based photosensitizer riboflavin, without the addition of dextran, which leads to dehydration of the sclera and an increase in its permeability to ultraviolet light, which increases the risk of damage to the inner layers of the eye. Key words: scleral crosslinking, ultraviolet A, riboflavin, experiment, myopia.

Lessons Learned: a knowledge management tool for learning about radiation accidents

According to the International Atomic Energy Agency (IAEA), the lessons learned (LL) in a radiation accident are extremely important in the building of learning about accidents, identifying best practices and preventing new accidents from occurring – making that if they do, the damage could be mitigated. Thereby, it was noted that the problems identified from the accident analysis led to the adoption of a series of measures to make facilities safer and more prepared for such accidents. Thus, is evident that the analysis of the LL about radiation accidents is a powerful learning tool in the field of radiation protection, opening space for discussions of a wider knowledge about nuclear energy. It is then observed the importance of evaluating LL to strengthen the Nuclear Knowledge Management (NKM). In this sense, the objective of this paper is to demonstrate to students of a Postgraduate course on Radiation Protection how to carry out a bibliographical review on the accidents involving radiation material, based in the main publications of the IAEA about LL. It is understood that, in relation to the dissemination of knowledge, the analysis of the LL as a tool for NKM is of extra relevance, not only for studies and learning in the area, but mainly for the prevention of accidents.

Beam Hazards and Ionising Radiation

This chapter treats hazards originating from particle beams. The interaction of charged particle beams with matter is described. Beam loss can cause material damage in structural and electronic components. Ionising radiation is introduced by a description of the different types of radiation. Then, the sources of ionising radiation at accelerators are defined: beam loss is the origin of prompt ionising radiation. Material activated by the passage of particle cascades is a long-lived source of ionising radiation. The chapter is closed with a description of radiation dosimetry and radiation protection at accelerators.

Modified I-shaped hexa-band near perfect terahertz metamaterial absorber

Purpose A novel and simple six-band metamaterial absorber is proposed in the terahertz region, which is composed of an I-shaped absorber and circular ring with four gaps and a continuous metal ground plane separated by only 0.125 mm polyimide dielectric substrate. Initially, I-shaped resonator gives three bands at 0.4, 0.468 and 0.4928 THz with the absorptivity of 99.3%, 97.9% and 99.1%, respectively. The purpose of this paper is to improve the number of bands, for which the authors added the circular ring with four gaps, so the simulated metamaterial absorber exhibited six absorption peaks at 0.3392, 0.3528, 0.3968, 0.4676, 0.4768 and 0.492 THz, with the absorption rate of 91.4%, 94.2%, 94.9%, 90.3%, 77.5% and 97.4%, respectively. The surface current distribution and angle independence are explained for all the six frequencies which are used to analyze the absorption mechanism clearly. Structure maximum uses the squares and circles, so it will make the fabrication easy. The multiband absorbers obtained here have potential applications in many engineering technology, thermal radiation, material detection and imaging and optoelectronic areas. Design/methodology/approach This paper presents the design of the six-band metamaterial absorber which is from the I-shaped resonator and circular ring with four gaps and the metallic ground plane separated by the 0.125 polyimide dielectric substrate. The absorber exhibited six absorption peaks at 0.3392, 0.3528, 0.3968, 0.4676, 0.4768 and 0.492 THz, with the absorption rate of 91.4%, 94.2%, 94.9%, 90.3%, 77.5% and 97.4%, respectively. From the fabrication point of view, the proposed six-band metamaterial absorber has a very simple geometrical structure, and it is very easy to be fabricated. Findings The authors present a new and simple design of six-band absorber based on an I-shaped absorber and circular ring with four gaps and a metallic ground plane separated by a polyimide layer having the thickness of 0.125 mm. Six different resonance absorption peaks are found at 0.3392, 0.3528, 0.3968, 0.4676 , 0.4768 and 0.492 THz. Surface current distribution and angle independence plot have been studied to understand the absorption behavior of the designed terahertz metamaterial absorber. Originality/value The multiband absorbers obtained here have potential applications in many engineering technology, thermal radiation, material detection, security, sensors, imaging and optoelectronic areas.