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  • 2025

    Abstract

    This study implements the comparative study of Casson and Williamson nanofluids by considering the impacts of linear thermal radiation and inclined magnetohydrodynamics. Here, we employ graphs to compare the variables affecting the behavior of non‐Newtonian and Newtonian fluids for a range of physical and dimensionless parameter values. The flow's coupled equations, which contain multiple independent variables, these equations can then be changed into a single independent variable by adding similarity variables and can be solved by applying the shooting method. The effects of thermomigration and Brownian motion on nonlinear flow equations are graphically examined. For an array of radiation parameter values, we have observed that the Newtonian fluid's concentration is lesser than that of both the non‐Newtonian fluids and also noticed that Newtonian fluids converge a little sooner than Casson and Williamson fluids. The primary innovation is shown in Table 1, where the mass transfer and heat transfer values are contrasted with the limiting circumstances of previous research findings that are documented in the literature.


    • Book : 54(1)
    • Pub. Date : 2025
    • Page : pp.145-166
    • Keyword :
  • 2025


    • Book : 1071()
    • Pub. Date : 2025
    • Page : pp.170079
    • Keyword :
  • 2025

    Abstract

    This paper investigates the magnetohydrodynamic hybrid nanofluid flow between two non-parallel walls, consisting of Cu − Ag nanoparticles suspended in H2O as the base fluid, which stretch or shrink under the influence of heat transfer with a heat source/sink. This analysis considers the impact of thermal radiation and porous media on the velocity and temperature profiles. The analysis is relevant in engineering applications such as cooling systems, lubrication, and advanced material manufacturing where precise heat and flow control are crucial. The nanoparticle volume fraction is modeled as an uncertain parameter, using Gaussian and triangular fuzzy numbers, specifically GFN(0.025, 0.01, 0.01) and TFN(0, 0.025, 0.05). A double parametric approach for fuzzy numbers, along with the homotopy method, is employed to investigate the uncertain effects of key physical parameters such as the stretching/shrinking parameter, Reynolds number, magnetic parameter, Darcy number, Eckert number, radiation parameter, and the volume fraction of nanoparticles on the fuzzy velocity and temperature profiles of the hybrid nanofluid flow in convergent and divergent channels. The numerical results are validated through experimentation, demonstrating strong agreement in both the crisp and uncertain scenarios using triangular and Gaussian fuzzy senses, and showing consistency with previously established findings.


    • Book : 100(1)
    • Pub. Date : 2025
    • Page : pp.015233
    • Keyword :
  • 2025

    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.


    • Book : 100(1)
    • Pub. Date : 2025
    • Page : pp.015018
    • Keyword :
  • 2025


    • Book : 242(1)
    • Pub. Date : 2025
    • Page : pp.115890
    • Keyword :
  • 2025


    • Book : 266()
    • Pub. Date : 2025
    • Page : pp.120470
    • Keyword :
  • 2025

    Abstract

    OBJECTIVE

    To evaluate the radiation dose to personnel locations during simulated head and limb scans with a novel equine standing CT (sCT) system.

    METHODS

    Measurements were made with the use of a helical fan beam sCT system (Equina; Asto CT Inc). Scatter radiation was measured in different positions in the sCT room to mimic the location of the control operator, horse handler, and lead rope handler during simulated equine head and limb imaging. Operator/handler dose was quantified at each location using entrance air kerma measured with a spherical ionization chamber and electrometer.

    RESULTS

    Radiation dose to the control operator, horse handler, and lead rope handler locations wearing a lead apron during simulated head imaging was 13.3, 3.5, and 6.8 µGy, respectively. Radiation dose to the control operator location wearing a lead apron was 1.3 µGy, and dose to the lead rope handler location wearing a lead apron was 0.2 and 5.4 µGy during simulated pelvic limb and thoracic limb imaging, respectively.

    CONCLUSIONS

    With the more widespread clinical use of equine sCT units in clinical practice, there is concern for increased risk of radiation exposure to personnel who stay in the sCT room during scanning. The control operator location had the highest dose during simulated head imaging, and the lead rope handler location in thoracic limb sCT had the highest dose during simulated limb imaging. Limiting the number of personnel in the sCT room, rotating personnel between handler positions, increasing operator distance from the scanner, and using lead shields and eyeglasses are recommended.

    CLINICAL RELEVANCE

    Our findings suggest that scanning large numbers of horses per year with the Asto CT Equina would not lead to occupational radiation exposure above the recommended safe threshold for handlers using lead shields and eyeglasses.


    • Book : 263(1)
    • Pub. Date : 2025
    • Page : pp.63-70
    • Keyword :
  • 2025


    • Book : 81(1)
    • Pub. Date : 2025
    • Page : pp.n/a
    • Keyword :
  • 2025


    • Book : 266()
    • Pub. Date : 2025
    • Page : pp.120504
    • Keyword :
  • 2025


    • Book : 242(pd)
    • Pub. Date : 2025
    • Page : pp.116086
    • Keyword :