Generation Of Radiation Research Articles

Employing the Akbari Ganji Method (AGM) to conduct a semi-analytical analysis of transient Eyring-Powell compressible flow in a tensile Surface under the influence of a magnetic field

This study explores the transfer of mass and heat within unstable two-dimensional flows of non-Newtonian material under conditions involving radiation generation, absorption, and thermal radiation. Additionally, it investigates the impact of magnetic hydromagnetic joule (MHD) heating on these processes. The researchers converted the partial differential equations into ordinary ones through appropriate transformations. Subsequently, a new idea was considered, involving coupling fractional differential equations using the AGM method, with an order of 0.5 < a <0.8 and the initial condition x (0) = x0. A new technique is introduced to find the exact solution of fractional differential equations by solving the correct order differential equations. The primary aim of this paper is to explore the impact of parameter variations on velocity, temperature, local skin friction coefficient, and local Nusselt and Sherwood numbers. This article investigates the effect of multi-parameter changes on local skin friction coefficient and Schmidt number. In most fluid heat transfer problems, especially in non-Newtonian fluids, fractional differential equations are widely used in liquids. The obtained results indicate that the Lorentz force, influenced by the magnetic field parameter (Ha), diminishes the velocity distribution. Additionally, it is observed that the temperature profile decreases as the radiation parameter (R) increases.

Effects of Heat Generation and Radiation on Darcy Convective Non-Newtonian Power Law Liquid with Yield Stress over a Vertical Plate

The effects of heat flux, and thermal buoyancy on mixed convective flow for a non-Newtonian power law liquid with yield stress via a vertical plate filled with a porous material under the influence of thermal radiation, and heat production are investigated in this topic. For this model, The PDE's that govern the flow are constructed and converted to a set of ODE's using appropriate transformation and the resultant ODEs are quantitatively determined using Shooting technique. The impacts of different flow regulating factors such as index parameter, yield stress, radiation, and heat generation are illustrated through graphical representation for fluid properties. This research shows that the velocity distribution, Nusselt and Sherwood numbers declines as the dimensionless rheological parameter rise, but temperature and concentration profiles exhibit the reverse tendency. Also, the velocity, temperature curves and mass flux grow as the radiation parameter rises, whereas the concentration curves and heat flux fall as the radiation parameter rises. For a specific case, a comparison with Lakshmi Narayana et al.,13 was made, and a great agreement was established.

High power single crystal KTA optical parametric amplifier for efficient 1.4–3.5 µm mid-IR radiation generation

In this paper, we present a single crystal, KTA (potassium titanyl-arsenate, KTiOAsO4) based picosecond optical parametric amplifier pumped by an in-house built 1030 nm Yb:YAG thin-disk laser, capable of tunability from 1.46 to 3.5 µm, operating at 90 kHz, with high average power in the signal and idler beams. The highest output power of 8.9 W was reached for the 1750 nm signal beam with 19% conversion efficiency and the respective 2500 nm idler beam power was 6.2 W with 13% efficiency. The highest combined signal and idler mid-infrared power was 17 W at the 2060 nm wavelength degeneracy point.

Experimental simulation of the generation of microwave radiation during the interaction of a lightning discharge with an aircraft

On a specialized testing installation — a high-voltage Marx generator, which allows the formation of a spark discharge up to 20 meters long, the process of the impact of lightning radio emission in the microwave range on an aircraft (AC) is simulated. A metal AC model made on a scale of 1:50 was placed in a 9 m long rod-plane spark gap. A positive voltage pulse was applied to the high-voltage electrode from the generator (front 100 μsec, duration 7500 μsec). The generated spark discharge passed through the AC model. It was found that when the spark channel passes through the body of the model, electromagnetic pulses of the microwave range with a duration of less than 500 psec and a rise time of less than 100 psec arise. The measurement of the resulting microwave pulses was carried out using special radio equipment in the subnanosecond range. High-speed photography of the discharge development, carried out synchronously with electromagnetic measurements, showed that microwave pulses (up to 10 GHz) arise at the stage of development of the spark discharge leader in the part of the “high-voltage electrode – insulated model” gap. Such pulses can be considered as a factor dangerous for various AC microwave radio systems, when the AC is struck by lightning, as well as for other objects, including power facilities, which contain equipment with microelectronics. Such microwave pulses can also occur during nearby lightning discharges (for example, in a lightning rod of a power substation), when a powerful streamer corona occurs on devices and wires of ultra-high voltage lines), and when a high-voltage spark discharge occurs when switching equipment (disconnectors, arresters) is triggered. In this case, disruptions are possible in the operation of control equipment (for example, relay protection devices) that contains microelectronics, as well as various communication means available at electric power facilities operating in the microwave range (above 1 GHz).

Features of Adaptive Phase Correction of Optical Wave Distortions under Conditions of Intensity Fluctuations

An analysis of the features of measurements and correction of phase distortions in optical waves propagating in the atmosphere at various levels of turbulence was performed. It is shown that with increasing intensity fluctuations, the limiting capabilities of phase correction decrease, and the phase of an optical wave that has passed through a turbulence layer consists of two components: potential and vortex. It was found that even in the region of weak fluctuations there is an overlap of spectral filtering functions for intensity and phase fluctuations. Areas of turbulence inhomogeneities have been identified that will have mutual influence and negatively affect the operation of the phase meter. It is noted that correlation functions, both phase and intensity, are less susceptible to this compared to structural functions. The results of experimental studies on the reconstruction of the wavefront of laser radiation distorted by atmospheric turbulence using a Shack–Hartmann wavefront sensor during vignetting and central screening of the entrance pupil in the optical system are presented. Studies have been carried out on the propagation of laser radiation along a horizontal atmospheric path for various levels of turbulence. The results are analyzed in terms of Zernike polynomials.

Quantum refraction effects in pulsar emission

ABSTRACT Highly magnetized neutron stars exhibit the vacuum non-linear electrodynamics effects, which can be well-described using the one-loop effective action for quantum electrodynamics. In this context, we study the propagation and polarization of pulsar radiation, based on the post-Maxwellian Lagrangian from the Heisenberg–Euler–Schwinger action. Given the refractive index obtained from this Lagrangian, we determine the leading-order corrections to both the propagation and polarization vectors due to quantum refraction via perturbation analysis. In addition, the effects on the orthogonality between the propagation and polarization vectors and the Faraday rotation angle, all due to quantum refraction are investigated. Furthermore, from the dual refractive index and the associated polarization modes, we discuss quantum birefringence, with the optical phenomenology analogous to its classical counterpart.

Compressing of experimental and simulated results of electron beam interaction with FFF-printed samples

One of the important parameters characterizing the interaction of electron beams with matter is the depth dose distribution. To develop a new approach for shaping electron beams using specially created materials suitable for the manufacture of complex 3D-printed devices, it is necessary to analyze the features of ionizing radiation propagation. In this work, numerical simulations and experimental studies of the interaction between electron beams and plastic materials weighted with metallic impurities of different concentrations, suitable for fabricating samples using the rapid prototyping method, were carried out. Sets of plates made from the investigated plastics were created using the fused filament fabrication (FFF) technique. Since the FFF sample fabrication process involves forming objects from a thermoplastic mass through layer-by-layer alignment, a distinctive feature of the printed samples is their lower actual density compared to the density of the material (filament) from which they are made. Taking this fact into account, the actual density of the polymer plates was calculated. Based on this data, numerical models of the plastic materials weighted with metallic impurities were developed, and virtual models of the experimental setup were created to calculate the electron beam depth dose distributions in the materials. In the next step of the investigation, experimental studies were performed using electron beams with energies of 6 and 10 MeV. Pre-calibrated GafChromic EBT3 dosimetry films were used as detectors to obtain the experimental data on the electron beam depth dose distributions in the materials under consideration. It was observed that with an increasing concentration of metal impurities in the plastic base, the depth dose distribution moves into smaller thicknesses. It was observed that the simulation and experimental results are in good agreement.

The law of infrared radiation generation and evolution of coal-rock fracture under load

In order to study the formation mechanism and evolution law of infrared radiation (IR) of coal-rock. A mathematical model of pressure-IR for coal-rock under loading conditions was developed based on theories such as frictional heat generation and heat conduction. The results indicate that: (1) IR and stress exhibit a one-dimensional quartic function relationship, which is consistent with the strong correlation shown by the experimental data curve. As the loading stress increases, the infrared radiation temperature of the coal-rock surface increases. (2) From the simulation results, it can be seen that the increase in surface temperature of coal-rock is essentially influenced by the heat transfer of internal heat sources. The trend of temperature fluctuations is similar for both, with both increasing with ambient temperature and loading rate. And this characteristic change is independent of external loading factors. (3) The IR temperature varies in stages under different loading conditions. In addition, the surface temperature of the coal-rock before fracturing is affected by the frictional heat generation between cracks, resulting in an overall upward trend. When it is about to break, a precursor to the fracture appears. The final IR on the surface of coal-rock increased by 0.04–0.13 °C, which is consistent with the simulation results. It is consistent with the simulation results and reveals the evolution law of IR. The results of this work provide theoretical evidence for the prediction of dynamical disasters in coal and rocks.

Pulsating magnetohydrodynamic hybrid nanofluid flow with thermal radiation, viscous dissipation, and entropy generation: Application to bio-nanomedicine

The aim of this investigation is to explore the flow phenomena in two distinct hybrid nanofluids (with micropolar fluid as the base fluid) undergoing hydromagnetic pulsation between two vertical walls, accompanied by entropy generation. This study also explores the unique heat transfer characteristics of F e 3 O 4 − Ti O 2 and A l 2 O 3 − MgO hybrid nanofluids, with the effects of Ohmic heating, thermal radiation, and viscous dissipation. The goal of using hybrid nanofluids is to improve the performance of biological systems such as nano-drug delivery in arteries, magnetic bio-separation, artificial kidneys, pressure surges, magnetofection agents, biomedical engineering, cancer treatments, and brain tumor treatment. The governing partial differential equations are transformed into a system of ordinary differential equations, which are then solved numerically by a shooting technique with a fourth-order Runge-Kutta method using a bvp4c MATLAB solver. Graphical explanations are provided for the flow variables such as the velocity, the microrotation, the temperature, the entropy generation, and the Bejan number. The heat transfer rate is an increasing function of the thermal radiation parameter; when the thermal radiation parameter increases from 1 to 3 the increases in the heat transfer rates in micropolar fluid (the base fluid), first hybrid nanofluid ( F e 3 O 4 − Ti O 2 ), and second hybrid nanofluid ( A l 2 O 3 − MgO ) are respectively 55%, 51%, and 43.86%. However, while the heat transfer rate (the Nusselt number) is a diminishing function of the Hartmann number. Further, the outcomes reveal that the hybrid nanofluids with emerging physical effects are helpful to treat cancer patients, recovering the damaged tissues and cells in arteries, and various medical-related procedures.

Controlled terahertz emission and electron localization dynamics in semiconductors

Dynamic localization has been thoroughly studied since 1986 by Dunlap in superlattice structures. However, its implications for terahertz (THz) radiation have not been fully explored. Here, we investigate the interplay between dynamic localization and THz radiation generation in semiconductor structures. Utilizing a two-color laser field, we reveal that intraband current is the primary source of THz radiation. Furthermore, we identify minima in THz radiation yield at specific laser field strengths, indicating the presence of dynamic localization. The relative phase of the two-color laser field and dephasing time can manipulate the extent and range of dynamic localization, thereby influencing the efficiency of THz radiation. Our findings provide valuable insights into simultaneous investigations on materials across different time scales.

Plasmoid Formation and Strong Radiative Cooling in a Driven Magnetic Reconnection Experiment.

We present the first experimental study of plasmoid formation in a magnetic reconnection layer undergoing rapid radiative cooling, a regime relevant to extreme astrophysical plasmas. Two exploding aluminum wire arrays, driven by the Z machine, generate a reconnection layer (S_{L}≈120) in which the cooling rate far exceeds the hydrodynamic transit rate (τ_{hydro}/τ_{cool}>100). The reconnection layer generates a transient burst of >1 keV x-ray emission, consistent with the formation and subsequent rapid cooling of the layer. Time-gated x-ray images show fast-moving (up to 50 km s^{-1}) hotspots in the layer, consistent with the presence of plasmoids in 3D resistive magnetohydrodynamic simulations. X-ray spectroscopy shows that these hotspots generate the majority of Al K-shell emission (around 1.6keV) prior to the onset of cooling, and exhibit temperatures (170eV) much greater than that of the plasma inflows and the rest of the reconnection layer, thus providing insight into the generation of high-energy radiation in radiatively cooled reconnection events.

Reevaluating Cosmic Origins: A Critical Analysis of Relic Radiation and Cosmometric Assumptions in Big Bang Cosmology

This article presents a critical examination of two key aspects of Big Bang cosmology: the nature and observability of cosmic microwave background (CMB) radiation and geometric inconsistencies or “cosmometric contradictions” within established approaches to cosmology. By dissecting the conventional interpretation of the CMB as relic radiation from a primordial fireball, we uncover that the standard model’s reliance on a spatially homogeneous fluid to represent radiation and matter underestimates the propagation of radiation and leads to the conclusion that the observability of the CMB contradicts its purported origins. Treating free radiation as if it expanded with the universe while disregarding that it escapes from its source at the speed of light is termed here as the “relic radiation blunder”. Furthermore, we delve into the cosmometric contradiction, highlighting how the calculated distances in standard cosmology imply a universe that exceeds the spatial limitations of its own foundational premise. This makes it evident that standard cosmology is not a unitary theory but involves models with conflicting spatial extensions. The analysis suggests a need for a revised understanding of redshift phenomena and cosmic expansion. It advocates for a reassessment of the underpinnings of cosmology, urging the scientific community to consider alternative frameworks that reconcile these critical inconsistencies. This work challenges the inviolable core of established cosmological theory, calling for a paradigm shift to foster foundational advances in our understanding of the universe.

Probing Zee-Babu states at muon colliders

The Zee-Babu model is a minimal realization of radiative neutrino mass generation mechanism at the two-loop level. We study the phenomenology of this model at future multi-TeV muon colliders. After imposing all theoretical and low-energy experimental constraints on the model parameters, we find that the Zee-Babu states are expected not to reside below the TeV scale, making it challenging to probe them at the LHC. We first analyze the production rates for various channels, including multi singly charged and/or doubly charged scalars at muon colliders. For concreteness, we study several benchmark points that satisfy neutrino oscillation data and other constraints and find that most channels have large production rates. We then analyze the discovery reach of the model using two specific channels: the pair production of singly and doubly charged scalars. For the phenomenologically viable scenarios considered in this study, charged scalars with masses up to O(3–4) TeV can be probed for the center-of-mass energy of 10 TeV and total luminosity of 10 ab−1. Published by the American Physical Society 2024

THz generation and spatiotemporal variation of two cross‐focused Gaussian laser pulses in plasma

AbstractThe impact of spatial and temporal evolution of nonlinear mixing of two Gaussian laser pulses propagating in plasma on generation of terahertz (THz) radiation have been investigated taking into account the ponderomotive nonlinearity. By calculating the modified electron density of plasma caused by the finite ponderomotive force of the pump lasers and using wave equation and paraxial ray approximation, two coupled governing equations for temporal and spatial pulse‐width parameters have been derived. The electric field of the THz wave as a result of nonlinear current density induced by the beat ponderomotive force of the pulses was extracted. Combined effects of initial laser and plasma parameters on the behavior of self‐compression and self‐focusing as well as THz radiation generation were investigated. The numerical results indicated a considerable spatiotemporal compression takes place within a specific range of laser intensity, exhibiting a saturation intensity point where the compression process reaches its maximum extent. It is observed that the generated THz radiation also strongly depends on the spatiotemporal dynamics of the pump pulses. The maximum THz amplitude corresponds to the strongest pump pulse compression extent.

Heat transfer in hybrid nanofluid flow between two coaxial cylinders

This study intends to investigate hybrid nanofluid flow between two permeable cylinders in the presence of thermal radiation and heat generation. The numerical solutions are obtained using the finite difference method. The influence of nanoparticle fraction, porous medium, radiation, heat generation, and angular frequency on the velocity, temperature, and Nusselt number are presented using graphs and tables. It was observed that the maximum velocity was attained by TiO2/water nanofluid, whereas the highest temperature distribution is observed in TiO2-Ag/water. Furthermore, the Nusselt number of the fluid increased by 17.5%, 19.7%, and 21.7% when TiO2, TiO2-Ag, and Ag nanoparticles were added to it, respectively.

Generation of Radiation with a Tunable Comb Spectrum in Ring Fiber Cavities Based on Active Photonic Crystal Structures

Generation of Radiation with a Tunable Comb Spectrum in Ring Fiber Cavities Based on Active Photonic Crystal Structures

Модель открытой квантовой системы для описания работы эрбиевого лазера

A quantum mechanical system consisting of an electromagnetic mode interacting with a set of erbium atoms is considered. For the density matrix of this system, the Gorini-Kossakovsky-Sudarshan-Lindblad master equation was considered in the local approach. From this master equation, equations are obtained that describe the average population of the electromagnetic mode and erbium atoms. For these equations, laser radiation generation curves were obtained and a comparative analysis with rate equations was carried out. It is shown that the presence of terms responsible for spontaneous emission in the resulting equations leads to a smoothing of the laser radiation generation threshold.

THz radiation distribution for the identification of infiltrating ductal carcinoma in human breast model: a computational study

With numerous biomedical applications of terahertz (THz) imaging, spectroscopy, and sensing, the THz regime of the spectrum is quickly emerging as an important area of research with the potential to usher in a new era in the healthcare industry. In the medical field, THz radiation has been explored to diagnose and monitor several ailments, including foot diabetes, skin dryness, wounds, and burns. Compared to X-rays, THz waves' phase sensitivity to bodily fluid levels and water results in superior contrast and stronger absorption. This feature makes THz potentially useful for the diagnosis of various malignant tumor forms because cancerous tumors have higher water molecule contents than healthy tissues. The current study presents a computational analysis of a CW-THz point-by-point scanning technique for breast cancer detection. COMSOL multiphysics platform was utilized to create a multilayer three-dimensional breast model containing an irregular-shaped infiltrating ductal carcinoma in the glandular layer. The propagation of the THz radiation in the constructed breast model was simulated based on the radio frequency module and electromagnetic waves in the frequency domain interface. Furthermore, different volumes and locations of the induced tumor were examined. The results demonstrated significant disparities in the acquired electric distribution at different tumor sizes and sites between normal and diseased breasts. The resultant electric field for healthy breast ranged from 1.1 × 10–5 to 0.61 V/m, however, the electric field ranges following tumor addition fluctuate based on its volume and location. Additionally, the position of the THz source and detector array influences the reflected THz signal.

Radiation shielding for inertial electrostatic confinement fusion system utilizing concrete and water

In this investigation, the impact of water thickness and various types of concrete materials, each characterized by different densities and elemental compositions, is examined for their role in shielding a radiation generator based on Inertial Electrostatic Confinement Fusion (IECF) device. The study focuses on assessing several vital parameters, including the effective removal cross-section (∑Rt) for fast neutrons, total mass attenuation coefficients (μmt), linear attenuation coefficients (μl), half-value layer (HVL), and mean free path (MFP) for X-rays across different concrete types. Different water thicknesses around the IECF chamber, ranging from 0.5 to 10.0 cm, are investigated, and five concrete types are evaluated: Ilmenite-magnetite Concrete (IMC), Ordinary Concrete-1 (OC1), Barite-containing Concrete (BC), Ordinary Concrete-2 (OC2), and Serpentine-containing Concrete (SC). The results indicate that, among these materials, SC requires the least thickness to attenuate 2.45 MeV generated from IECF to 1/100th of its initial intensity across varying water thicknesses (6.5 cm in case of 5 cm water thickness). The values of μmt, HVL, and MFP are also calculated for different water thicknesses and X-ray energies (ranging from 0.2 to 3.0 MeV). These calculations highlight BC as the material requiring the least thickness to attenuate X-rays to 1/100th of their initial intensity. Moreover, neutron dose rate measurements are conducted on a commercial IECF system shielded with 50 cm of water and operated at a neutron intensity of 105 ns−1, which was ∼12 nSv/h on average, approximately 0.002% of the initial intensity. This underscores the efficacy of water shielding in attenuating the outcomes of IECF.

Awareness Patterns Regarding Radiation Safety Management in Fields Related to Radiation Safety Regulations: Focusing on Companies that Must Report Radiation Sources

Background: This study aims to analyze radiation safety management and regulatory perceptions, focusing on companies that must report radiation sources. The intent is to reduce the gap between regulation measures and addressing real concerns while improving practical safety management measures and regulations for all stakeholders.Materials and Methods: Radiation safety officers at a total of 244 reporting companies using radiation generators (79.8%) and sealed radioisotopes (15.1%) were surveyed using a questionnaire.Results and Discussion: The perception that regulation is stronger than the actual risk of the radiation source used was 3.47 points (out of 5 points), indicating a score above average. The most important factors and considerations were education and training (48%) as a human factor, safety devices of the radiation source (71.3%) as a hazardous material factor, the use of radiation (50.8%) as an organizational environment, and the radiation effect of nearby facilities (67.2%) as a physical environment. Radiation safety management educational experience (&lt;i&gt;F&lt;/i&gt;=5.030, &lt;i&gt;p&lt;/i&gt;&lt;0.01), the group with high subjective knowledge (&lt;i&gt;t&lt;/i&gt;=6.017, &lt;i&gt;p&lt;/i&gt;&lt;0.001), and the group with high objective knowledge (&lt;i&gt;t&lt;/i&gt;=1.989, &lt;i&gt;p&lt;/i&gt;&lt;0.05) was found to be better at radiation safety management.Conclusion: It is necessary to standardize the educational experience regarding radiation safety management because each staff member has individual differences in educational experience. It is necessary to provide more information on how to solve radiation accidents via educational content. Applying radiation safety regulations based on the factors that significantly affect radiation safety management shown in this survey will help improve safety.