Radiation Reaction Research Articles

Unsteady MHD Free Convective Flow of a Micro‐Polar Fluids Over a Vertical Porous Plate in the Presence of Radiation and Chemical Reaction

ABSTRACTObjective of the paper is to investigate the motion of an unsteady free convective MHD flow of a micro‐polar fluid over semi‐infinite vertically moving porous plate in the presence of chemical reaction and thermal radiation. A transverse magnetic field is applied, assuming a low magnetic Reynolds number. We have discussed the effects of heat radiation due to a heat source and first order chemical reaction within the medium. The perturbation method is applied to solve the nonlinear coupled partial differential equations in their dimensionless form, converting them into a system of ordinary differential equations, which are then solved analytically. The effects of magnetic field, medium permeability, buoyancy force, heat source, concentration gradient, Prandtl number, thermal diffusion, heat radiation, and first order chemical reaction on velocity, temperature and concentration are discussed graphically. The graphical representations are generated using MATLAB software. For engineering interest, their effects on skin friction, heat and mass transfer in terms of Nusselt number and Sherwood number are discussed; numerical values are shown in tabular form. The results show that magnetic fields reduce fluid velocity, while thermal radiation decreases temperature, and chemical reactions lower concentration. Radiation increases skin friction and heat transfer, while chemical reactions reduce mass transfer. Findings have relevance in various problems and situations arising with micro‐polar fluidic devices, industrial like petroleum and lubrication, mixing etc.

Effects of hall current and thermal diffusion on unsteady MHD rotating flow of water based Cu, and TiO2 nanofluid in the presence of thermal radiation and chemical reaction

Effects of hall current and thermal diffusion on unsteady MHD rotating flow of water based Cu, and TiO2 nanofluid in the presence of thermal radiation and chemical reaction

Gravitational radiation reaction for compact binary systems at the fourth-and-a-half post-Newtonian order

Abstract We compute the gravitational radiation-reaction force on a compact binary source at the fourth-and-a-half post-Newtonian (4.5PN) order of general relativity, i.e., 2PN order beyond the leading 2.5PN radiation reaction. The calculation is valid for general orbits in a general frame, but in a particular coordinate system which is an extension of the Burke-Thorne coordinate system at the lowest order. With the radiation-reaction acceleration, we derive (from first principles) the flux-balance laws associated with the energy, the angular and linear momenta, and the center-of-mass position, in a general frame and up to 4.5PN order. Restricting our attention to the frame of the center of mass, we point out that the equations of motion acquire a non-local-in-time contribution at the 4.5PN order, made of the integrated flux of linear momentum (responsible for the recoil of the source) together with the instantaneous flux of center-of-mass position. The non-local contribution was overlooked in the past literature, which assumed locality of the radiation-reaction force in the center of mass frame at 4.5PN order. We discuss the consequences of this non-local effect and obtain consistent non-local equations of motion and flux balance laws at 4.5PN order in the center-of-mass frame.

Exploring slip-enhanced MHD Williamson nanofluid dynamics: interplay of a permeable stretching sheet with thermal radiation and chemical reaction

Exploring slip-enhanced MHD Williamson nanofluid dynamics: interplay of a permeable stretching sheet with thermal radiation and chemical reaction

ELECTROOSMOTIC FLOW OF MICROPOLAR NANOFLUID THROUGH A NON-DARCY POROUS MEDIA WITH VON NEUMANN STABILITY CONDITION

This study investigates the action of time-periodic temperature and nanoparticle concentration divergence on electroosmotic micropolar Eyring-Powell nanofluid flow through a non-Darcy porous medium and over an infinite vertical plate. The effects of viscous and Ohmic dissipation, heat source, thermal radiation, Dufour trait, and chemical reaction are considered. The complicated system of differential equations which governs the problem is transformed into a system of nonlinear algebraic equations by using the finite difference method. Numerical results for the velocity, microrotation velocity, temperature, and nanoparticle concentration distributions, as well as the skin friction, reduced Nusselt number, and Sherwood number, are obtained. It is noted that the velocity becomes greater with an escalating Helmholtz-Smoluchowski velocity. Meanwhile, it elevates when rising in chemical reaction order. The enriching in thermophoresis parameter causes a dwindling influence on the nanoparticle concentration while also causing an increase in temperature. This study is significant in many diverse medical implementations as nanoparticles are utilized in the treatment of cancerous tumors.

MHD flow in free convection over an exponentially stretched sheet submerged in a double-stratified medium

The inquiry presents magnetohydrodynamics (MHD) heat mixed with mass transfer free convective flow across an inclined sheet lodged in a doubly stratified medium with the impact of radiation, suction, heat source, chemical reaction, thermophoresis and soret. A variable magnetic field is also applied to the stretching sheet. The similarity transformation is used to turn the nonlinear controlling boundary layer PDEs (partial differential equations) of momentum, temperature and concentration into a set of nonlinear ODEs (ordinary differential equations). The ODEs are then numerically solved with the MATLAB bvp4c technique. The variation in flow, heat and concentration profiles caused by the various parameters associated with the problem, such as Hartmann number, suction parameter, Prandtl number, heat source parameter, Eckert number, radiation, thermal stratification, chemical stratification, thermophoretic and chemical reaction parameter are shown via graphs. Impacts on skin friction coefficient, heat and mass transfer rate are also depicted using tables for different parameters. The fluid velocity decreases with the rise in magnetic parameters in the presence or absence of suction. The fluid’s temperature escalates with the rise in heat source parameter and Eckert number in the presence of suction. The concentration profile escalates with the rise in solutal stratification parameter in the absence of suction.

Numerical Solutions for Radiative MHD Casson Nanofluid Flow with Slip, Heat Source, and Chemical Reactions over a Stretching Surface

MHD Casson nanofluid flow in the presence of viscous dissipation, thermal radiation and chemical reaction past a linear stretching surface is investigated. The problem is subjected to slip boundary conditions. The analysis of heat and mass transfer in the presence of Brownian motion and the thermophoretic diffusion effects are incorporated into heat and mass transfer. Nonlinear partial differential equations model governing the problems are transformed into the dimensionless nonlinear ordinary differential equations via similarity variables, then shooting method with sixth-order Runge- Kutta numerical scheme is used to solve the reduce system of Ordinary Differential Equations (ODE). Maple software is used to perform the simulation. The results are presented graphically and in tabular form and the conclusion is drawn that the flow field and other quantities of physical interest are significantly influenced by these parameters. Comparison between the obtained results and previous works are well in agreement. Numerical values of the local skin-friction, Nusselt number and nanoparticle Sherwood number are computed and analyzed. It is noted that the skin-friction coefficient decreases for the larger values of velocity ratio parameter, slip parameter, and increases with an increasing value of Casson parameter. It is also found that enhancing the chemical reaction parameter leads to decrease in concentration profile

Steady mathematical modeling and numerical analysis of Cross magneto‐nanofluid flow over a wavy surface with heat and mass transfer features

AbstractMixed convectively driven wavy flow of Cross‐generalized fluid is modeled on a wavy surface with the importance of wavy surface amplitude. The periodic nature of the flow is effectively configured and is declared the main theme of this study. However, some physical features are considered together with the flow of heat and mass. The effect of external magnetic field, heat generation/absorption, thermal radiation, and linear chemical reaction are comprehensively deliberated during the typical wavy flow. The low Reynolds approximation theory is utilized for the boundary layer governing equations. Specifically, the wavy surface amplitude is played an integral part in modeling the GNF. The mathematical equations are formed in terms of partial differential equations (PDEs) with the physical and chemical impacts. The nonlinear PDEs are then transformed into ordinary differential equations (ODEs) by utilizing the dimensionless local similar. The whole investigation is further extended with the features of heat and mass flows in the presence of Brownian motion and thermophoretic forces. To demonstrate the importance of the leading dimensionless physical factors, a modified version of the collocation methods, namely modified bvp4c is applied. The significant results are displayed via drag forces, heat and mass transmission rates, and velocity of the fluid. Significant uplifted behavior of skin friction is noticed by considering the higher values of wavy surface amplitude. The higher values of the newly introduced Weissenberg number are predicted an increasing velocity of the fluid. The higher Richardson number boosted the material's velocity. The rates of heat and mass flows are noticed higher for escalated values of chemical reaction and radiation parameters, respectively. The Brownian motion and thermophoretic forces enhanced the concentration of the materials. A strong comparison with the previous works is provided to ensure the validity of the entire numerical method.

Formulation and Evaluation of Aloe Vera-Based Herbal Lotion for Skin Moisturization and Healing

Background: An alternate treatment for radiodermatitis seems to be the use of herbal extracts, which are a source of antioxidant compounds that can protect against ionizing radiation and neutralize free radicals. Many recommendations about the management and prevention of side effects are predicated on the appropriate experience of radiation centers. We provide an overview of current studies that attempt to lessen radiation-induced skin damage through the application of topical treatments including herbal extracts, such as onco-cosmetics. Techniques: The scope of this paper is restricted to a critical evaluation of professional and scientific literature. It deals with preparations in various physicochemical forms, such as ointments, gels, and emulsions. We emphasize the relationship between the characteristics of the herbal extract, the type of skin care product used (preparation type, composition, dosage), and the assessment of the extract's effectiveness in avoiding and treating radiation reactions on the skin. Conclusions: Since herbal extracts belong to a class of cosmeceutical supplements, they can be used in recipes and added to preparations without a prescription. Since there are no specific rules, evaluating the efficiency of plant extracts in radiation is a challenging undertaking. Analysis of herbal extracts and recipes in terms of their physicochemical, dermatological, and performance properties should come before any studies. Keywords: plant extracts for skin care, onco-cosmetics, herbal medicine, radiodermatitis, and radiation treatment.

Photobiomodulation therapy for the management of acute radiation dermatitis in head and neck cancer: A case report

To assess the effectiveness of photobiomodulation therapy (PBMT) for the management of acute radiation dermatitis (ARD) in a head and neck cancer (HNC) patient. This case study examines a patient who developed a severe radiation reaction during radiotherapy for squamous cell carcinoma of the alveolus, which was successfully managed with supportive care, including PBMT. PBMT significantly reduced grade IV ARD and grade III oral mucositis to grade zero within one week after the completion of radiotherapy. The patient completed treatment without interruption or hospitalization. PBMT appears to be a safe and effective method for managing severe ARD. The incidence of radiation dermatitis may be influenced by factors such as the type of radiation equipment used and whether concomitant chemotherapy was administered as an adjunct. More studies are needed to establish standardized PBMT protocols. This case study supports the implementation of PBMT in clinical oncology practice.

Possibility of local radiation therapy of the prostate during radium223 therapy

Introduction. Patients with metastatic castration-resistant prostate cancer (mCRPC) are a complex and heterogeneous group whose primary treatment goals are to both prolong life and preserve quality of life. Among patients with mCRPC, there is a group with a progressive tumor process in the prostate gland, in which local irradiation along with systemic Ra 223 (Ra223) therapy would lead to improved oncological outcomes.Purpose of the study. To evaluate the efficacy and safety of Ra223 in patients with mCRPC in routine clinical practice and to assess the feasibility of local radiation therapy of the prostate in patients with mCRPC receiving Ra223 therapy.Materials and methods. This study included 189 patients with mCRPC who received 1 to 6 injections of Ra223 as part of routine clinical practice. The patients were divided into two groups. Group 1 included patients who received systemic therapy only – 153 (81%), while group 2 consisted of patients who received local irradiation of the prostate gland along with Ra223 therapy – 36 (19%) patients.Conclusions. The use of radium223 in combination with localized radiotherapy for the treatment of the prostate has shown promising results in increasing disease control rate (DCR) in patients with mCRPC. Concurrent localized irradiation of the prostate against the radium223 therapy background did not show the result in increased hematological toxicity, which favorably affecting the tolerability of the radionuclide treatment. At the same time, localized radiation reactions occurring during localized prostate irradiation did not prevent patients from completing the full course (six injections) of the radionuclide radium223 treatment.

Alena Tensor in unification applications

Abstract Alena Tensor is a recently discovered class of energy-momentum tensors that provides mathematical framework in which, as demonstrated in previous publications, the description of a physical system in curved spacetime and its description in flat spacetime with fields are equivalent. The description of a system with electromagnetic field based on Alena Tensor can be used to reconcile physical descriptions. (1) In curvilinear description, Einstein Field equations were obtained with Cosmological Constant related to the invariant of the electromagnetic field tensor, which can be interpreted as negative pressure of vacuum, filled with electromagnetic field. (2) In classical description for flat spacetime, three densities of four-forces were obtained: electromagnetic, against gravity (counteraction to gravitational free-fall), and the force responsible for the Abraham-Lorentz effect (radiation reaction force). Obtained connection of Einstein tensor with gravity and radiation reaction force, after transition to curvilinear description, excludes black hole singularities. There was obtained Lagrangian density and generalized canonical four-momentum, containing electromagnetic four-potential and a term responsible for the other two forces. In this description charged particles cannot remain at complete rest and should have spin, their energy results from the existence of energy of magnetic moment and the density of this energy is part of the Poynting four-vector. The distribution of charged matter was expressed as polarization-magnetization stress-energy tensor, what may explain why gravity is invisible in QED. 3) In quantum picture, QED Lagrangian density simplification was obtained, and the Dirac, Schrödinger and Klein–Gordon equations may be considered as approximations of the obtained quantum solution. Farther use of Alena Tensor in unification applications was also discussed.

Heat and Mass Transfer Performance of Dufour and Heat Source on Casson Fluid Flow Past an Inclined Oscillating Rotating Porous Plate with Chemical Reactions and Thermal Radiation

The current research presents an analytical interpretation of unsteady-free convective hydromagnetic boundary layers, focusing on how the Dufour effect, thermal radiation, and chemical reactions influence Casson fluid flow through a rotating porous medium, around an inclined oscillating platewithin a uniformfield. The governing equations are solved using the Laplace transform method, with the results presented visually through numerical values of Casson fluid velocity, temperature, and concentration at the plate, based on various key parameter values. The study examines how the Casson fluid behaves compared to Newtonian fluid, with the Casson fluid demonstrating a higher velocity. The findings also show that, as temperature decreases, parameters such as the Grashof number, Dufour effect, thermal radiation parameter (R), and chemical reaction parameter (K) increase. Additionally, increasing the chemical reaction parameter (K) causes a reduction in concentration. In analyzing the fluid flow, the study also measured the influence of Prandtl, Schmidt, thermal, and Grashof numbers. The results indicate that the velocity of the fluid decreases with higher radiation levels, but increases when the heat source and Grashof number are elevated. Similarly, rising radiation levels reduce temperature, while a stronger heat source increases it.

Efficacy of low-temperature argon plasma in the rehabilitation of patients undergoing radiation therapy for breast cancer

Background: During radiation therapy for breast cancer, healthy tissues are damaged, leading to both systemic and local reactions, including radiation dermatitis with such symptoms as erythema, dryness, peeling, and pain. Disturbances of the microcirculation lead to hypoxia and fibrosis. The use of low-temperature argon plasma is a promising method for preventing acute radiation-induced skin damage, which is crucial for maintaining quality of life, preventing complications, and minimizing long-term effects. Aim: To evaluate the effectiveness of low-temperature argon plasma used in the complex medical rehabilitation of patients undergoing external radiation therapy for breast cancer. Materials and methods: A prospective, randomized interventional study was conducted involving 60 breast cancer patients undergoing radiation therapy. All patients received a course of medical rehabilitation, including general magnetic therapy, exercise therapy, balance response training on a biofeedback simulator, nutritional support, and sessions with a medical psychologist. In the main group (n = 30), rehabilitation included low-temperature argon plasma treatment. Outcomes were assessed using the RTOG scale for acute complications of radiation therapy and laser Doppler flowmetry. Results: After completing radiation therapy and complex medical rehabilitation, statistically significant differences were observed between the main group and the comparison group (which did not receive low-temperature argon plasma treatment) in the severity of radiation reactions on the RTOG scale (p = 0.016) and in peripheral blood flow parameters. Conclusion: Low-temperature argon plasma supports nutritional blood flow and active mechanisms for microcirculatory regulation, preserving skin blood supply and preventing severe acute radiation dermatitis.

Evaluating the Upper and Lower Lip as Critical Organs in Radiotherapy for Head and Neck Cancer Patients

Squamous cell carcinoma of the head and neck is condition associated with a poor prognosis. Current treatment methods are a combination of various techniques. Reactions after radiotherapy, particularly those affecting mucous tissues such as the lips, are a major issue after radiotherapy. This study aimed to assess the doses deposited on the lip area, considering its proximity to target areas during radiotherapy. Study was conducted on 100 patients with diagnosed head and neck cancers. These patients were treated with radiotherapy, sometimes combined with chemotherapy, and for some, it was postoperative treatment. The minimum, average, and maximum doses deposited on the lip area were assessed, divided into group I (neck) and group II (head). The lowest doses were observed in the larynx area, and the highest in the oral cavity (67.7% of the dose from 70 Gy and 76.46% from the minimum dose). Patients were further divided based on treatment methods, with the highest maximum lip dose found in those undergoing postoperative radiochemotherapy (Dmax 42.34Gy). Post-radiation reactions were then analyzed, showing higher reactions (lowest, average, and maximum) in group II (head area). Tumor location analysis showed the lowest maximum reaction according to the Dische classification in the larynx and other locations, and the highest in the pharynx. Postoperative patients with adjuvant radiochemotherapy had the highest minimal and maximum reactions. Despite the lack of statistical significance, the results suggest the importance of contouring the lips as a critical organ to reduce radiation reactions, potentially improving patients' quality of life.

Numerical simulation of rotating flow of CNT nanofluids with thermal radiation, ohmic heating, and autocatalytic chemical reactions

The dispersion of carbon nanotubes in conventional fluids provides a variety of applications, using their unique features to develop efficiency, performance, and functionality in many industrial and scientific processes. Some of the applications are energy conversion, fluid stirring, aligned nanocomposites, heat exchangers, electronics cooling, etc. Considering the aforementioned applications, this communication presents a comparative examination of the rotating flow of CNTs past a stretchable sheet with suction and velocity slip. This study is unique because it looks at the non-linear radiative, Darcy–Forchheimer, and rotational flow of CNTs past a stretchable sheet with considering ohmic heating and homogeneous/heterogeneous reactions. These type of issues have not been previously discussed. Suitable conversions are adopted to alter the governing nonlinear PDEs into nonlinear ODEs. The reduced ODEs are numerically reckoned by adopting the bvp4c scheme in MATLAB. The repercussions of flow factors on velocity, temperature, nanoparticle concentration, skin friction coefficients, and local Nusselt number are provided via tables and graphs. It is revealed that the primary velocity profile dwindles when augmenting the values of suction/injection, porosity, rotational, and magnetic field parameters. The temperature ratio and radiation parameters contribute to the thermal profile’s development. The magnetic field parameter and the Forchheimer number play a dual role in both directional skin friction coefficients. The larger values of radiation and temperature ratio parameters improve the heat transfer rate.

Thermophoretic particle deposition effect on a squeezed flow of radiative Jeffrey fluid past a sensor surface with uniform heat source/sink and chemical reaction

Abstract This anticipated model investigates the time-dependent, and incompressible 2D magnetized Jeffrey liquid flowing on a sensor surface placed between two infinite parallel plates with the existence of a uniform heat source/sink. The lower plate remains fixed while the upper plate is subject to squeezing. For the heat and mass transmission processes, the consequences of radiative heat flux, chemical reaction, and thermophoretic particle deposition are applied and analyzed. The envisioned model is supported by prescribed heat and mass flux conditions. The uniqueness of the proposed model is the analysis of the unsteady squeezed flow of Jeffrey liquid over a sensor surface, accounting for radiative heat flux, thermophoretic particle deposition, and variable thermal conductivity. The model possesses applications in microfluidic sensors, biomedical devices, thermal management systems, and inkjet printing. The equations comprising the model are subject to similarity transformations. The bvp4c package is utilized to analyze the dynamic flow system. The connotation of arising parameters with the associated profiles is depicted through graphs and tables. It is examined that fluid velocity, temperature, and concentration profiles are dwindling functions of squeezed parameter. It is also witnessed that the concentration of liquid drops with an enhancement of thermophoretic and chemical reaction parameters. The validation of the truthfulness of the envisioned model is an added feature of this study.

Sensitivity study of heat transfer in a Jeffrey ferro-hybrid nanofluid bioconvective squeezing flow with inclined MHD and higher-order chemical reaction: entropy analysis

Abstract The present investigation concentrates on analyzing heat transfer and entropy formation in a time-reliant bioconvective flow of a blood-based Jeffrey hybrid nanofluid via a squeezing channel that is suctioned or injected at the lower plate. Cu nanoparticles and Fe3O4 ferro-nanoparticles are suspended in base-fluid blood. Adding ferro-nanoparticles to a flow process allows for better control of the external magnetic field and improved heat transmission. Noble integration of an aligned magnetic field, Joule's heating, thermal radiation, and higher-order chemical reactions is taken into account in the flow in a porous media. An appropriate choice of similarity variables leads to the non-dimensionalization of the governing equations, that are subsequently solved by the homotopy analysis method (HAM), yielding a semi-analytical solution. An innovative feature of this research is the optimization of heat transfer by the application of the response surface methodology (RSM) technique. Additionally, sensitivity analysis was carried out to identify the most influential parameter. The study's findings indicate that increased suction reduces both velocity and temperature distributions in both the nanofluid and hybrid nanofluid models. In terms of thermal performance, the Blood/Fe3O4 - Cu hybrid nanofluid surpasses the Blood/Fe3O4 nanofluid. The rate of thermal energy transfer is highly sensitive to variations in the Eckert number, while thermal radiation has a relatively lesser impact. Moreover, elevated levels of the magnetic parameter, Eckert number, and nanoparticle concentration lead to augmented entropy formation. This mathematical model is effective for analyzing drug transport mechanisms throughout the human body and presents extensive potential applications in the fields of biology and healthcare.

MHD casson fluid flow over a stretching surface with suction, double stratification, and heat and mass transfer effects

Abstract In this article, we investigated the flow of a magnetohydrodynamic Casson fluid across an extending surface with exponential permeability in a double-stratified medium. Thermal radiation, suction, heat sources, viscous dissipation, and chemical reactions drive the stream field. We converted the flow describing partial differential equations into terms of ordinary differential equations by applying appropriate transformations. Next, we utilised the bvp4c package in Matlab to obtain numerical solutions for these equations. We explored and graphically showed the implications of different non-dimensional governing parameters for temperature, concentration, and velocity profiles. After analysis, we provide a tabular presentation of the friction factor, Nusselt, and Sherwood numbers. The Casson fluid temperature shows a rising trend for the solutal stratification parameter and a decreasing trend for the thermal stratification parameter, while the Casson fluid velocity shows a declining trend towards both of these parameters. The Casson fluid concentration also behaves differently depending on the stratification parameter; for example, it increases for thermal stratification and decreases for solutal stratification. We notice that an increase in the Casson parameter's value suppresses the velocity field. However, as the Casson parameter increases, both the temperature and the concentration improve. Furthermore, comparisons with previously published findings also support the current results. \sethlcolor{yellow}\hl{The study of MHD Casson fluid flow that includes suction, dual stratification, and the effects of heat and mass transfer is very useful in many areas, such as polymer processing, metallurgical engineering, biomedical applications, environmental sciences, and advanced cooling technologies.

Impact of Thermal Energy on Water and Ethylene Glycol (50:50)-Based Rotating Hybrid Nanofluid Past A Riga Surface with Radiation, Homogeneous and Heterogeneous Reactions

Hybrid nanofluid is crucial in improving the efficiency of heat transmission in thermal engineering applications, particularly the cooling of electrical equipment, heat exchangers, fuel cells, printing machines, etc. This study sought to investigate the augmentation of heat and mass transmission by the use of a rotating hybrid nanofluid consisting of a mixture of gold and silver nanoparticles suspended in water and ethylene glycol (50:50) past a heated Riga surface with velocity slip and suction. The energy equation is constructed using nonlinear radiation and heat consumption. The impact of both homogeneous and heterogeneous processes on the hybrid nanofluid is also explored. The governing mathematical model begins with partial differential equations that are converted into ordinary differential equations using a suitable conversion technique. The results of numerical computations are recorded as graphs and tables using the bvp4c scheme in MATLAB. It is noticed that both directional velocities undergo significant negative changes as a result of enhanced values of the rotational parameter. The higher levels of the radiation parameter resulted in significant enhancements in the thermal profile. The falling behavior of the nanoparticle concentration profile is recorded against a greater quantity of both chemical reaction parameters. Based on our analysis, when the Biot number changes from 0.4 to 0.8, the most significant heat transmission gradient occurs.