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Squeezing or squeeze flows have tremendous applications in applied fields, like engineering, biomedical sciences and rheological studies. This paper demonstrates the squeezing flow of kerosene-based nanoliquids between parallelly aligned plates, with a Riga-type fixed lower boundary. The effects of dispersing two types of copper-functionalized carbon nanotubes (CNTs), single-walled CNTs (SWCNTs) and multi-walled CNTs (MWCNTs) are examined. Using appropriate transformations, a self-similar ordinary differential system is derived from the governing model of partial differential equations and substantial boundary conditions. Using the homotopy analysis method (HAM) and the b v p 4 c package, analytical and numerical estimates are obtained, respectively. For higher values of the squeezing parameter, dimensionless temperature increases, while velocity patterns are upside-down. Moreover, increments in dimensionless parameters representing Riga constituent width, modified Hartmann number, nanoparticle concentration and radiation parameter improve heat transfer rates and thermal boundary layer thickness, however, adversely affect velocity. Despite enhanced friction effects, numerical results show that the Nusselt number increases as nanoparticle loads and radiation parameters increase. This suggests that convection rates are improved over conduction rates. Excellent agreement is found between analytical and numerical evaluations. Apparently, it is noticed that MWCNTs perform better than SWCNTs. [ABSTRACT FROM AUTHOR]

The flow at a time-independent separable stagnation point on a Riga plate under thermal radiation and electro-magnetohydrodynamic settings is examined in this research. Two distinct base fluids-H 2 O and C 2 H 6 O 2 and TiO 2 nanostructures develop the nanocomposites. The flow problem incorporates the equations of motion and energy along with a unique model for viscosity and thermal conductivity. Similarity components are then used to reduce these model problem calculations. The Runge Kutta (RK-4) function yields the simulation result, which is displayed in graphical and tabular form. For both involved base fluid theories, the nanofluids flow and thermal profiles relating to the relevant aspects are computed and analyzed. According to the findings of this research, the C 2 H 6 O 2 model heat exchange rate is significantly higher than the H 2 O model. As the volume percentage of nanoparticles rises, the velocity field degrades while the temperature distribution improves. Moreover, for greater acceleration parameters, TiO 2 / C 2 H 6 O 2 has the highest thermal coefficient whereas TiO 2 / H 2 O has the highest skin friction coefficient. The key observation is that C 2 H 6 O 2 base nanofluid has a little higher performance than H 2 O nanofluid., (© 2023. The Author(s).)

We report the ablation results for surface modification of polyimide Kapton HN foils using ultrashort femtosecond laser pulses. The modification threshold fluences for 75 μm thick films of polyimide were determined at different incident angles (0°, 20°, 30°, 45°, and 50°) for vertical and horizontal diameters. Ablation at oblique angles was investigated as such interactions are found during laser procedures with the eye that require scanning of the beam and are very important to know for the treatment of various eye diseases. Polyimide, in this study, was considered as a model for corneal sculpting. Use of ultrashort femtosecond laser pulses for high-precision patterning of the sample, without thermal damage to the surroundings, has been investigated. The relationship between the incidence angle with ablation threshold fluence, threshold energy, and beam radius are described. Also, threshold energies and threshold fluences for different thicknesses of polyimide were investigated.

In this study, the two-photon absorption excited fluorescence of the photosensitizer 4,4 ' -Bis(diethylamino)benzophenonin in different solvents is investigated by using mode-locked Ti:sapphire excitation having a wavelength of 800 nm with pulse duration of 150 fs at the rate of 1 kHz. The fluorescence signals excited by wavelengths of 800 and 400 nm have been compared. Contribution of these cross-section measurements for the two-photon polymerization processes is also reported.

We report two-photon absorption cross sections and two-photon excited fluorescence of the photosensitizer 4,4'-Bis(diethylamino)benzophenon and thioxanthone using a femtosecond laser delivering pulses of wavelength 800 nm and 150 fs duration at rates of 1 kHz. Values for the two-photon absorption cross section are derived by comparing the fluorescence signals excited by wavelengths of 800 and 400 nm using a second-harmonic generator. Fluorophore fluorescence intensities dependence with quadratic illumination laser power showed no significant deviation from the two-photon absorption process. Implications of these cross-section measurements for two-photon polymerization are discussed.