Revista Mexicana de Física

The study of the Influence of the geometry of the double legged ducts on the buildup factor and the transmitted flux

Z. Faik Ouahab — Mon, 01 Sep 2025 00:00:00 +0000

The analysis of neutron transport through ducts holds significant importance due to its applicability in numerous practical scenarios, particularly in systems involving complex duct geometries. The presence of these ducts is inevitable in several nuclear installations. In this work, we have developed a simulation program based on the Monte Carlo method that has been validated by the MCNPX calculation code. We have also introduced a new concept of buildup factor in order to study the effect of the geometry of the double legged duct on the buildup factor and the flux at the duct exit.

Cross section analysis of neutron-light nuclei systems using Modified Pöschl–Teller potential

P. Sahoo, K. C. Pradhan, D. Rout — Mon, 01 Sep 2025 00:00:00 +0000

The regular and irregular/Jost solutions of the Schrödinger equation with the Modified Pöschl–Teller potential are presented by implementing the differential equation technique to the problem. In this work the said potential is parameterized for nuclear systems by exploiting Jost formalism to estimate bound state energies and the scattering phase shifts. The results are in line with previous theoretical and experimental observations. The total elastic scattering cross sections are being calculated using the phase parameters.

Study of the phase dependency of RF cavities on gamma ray distribution

Mon, 01 Sep 2025 00:00:00 +0000

A front-to-end simulation study of a gamma irradiator was conducted, covering the entire process from the electron gun to the gamma rays going into a collimator, to investigate the impact of the RF phase on the irradiation process for continuous wave (CW) beams. Instead of considering an ideal monoenergetic beam to generate the gamma rays, we use a more complex simulation where initially, the electron gun generates a continuous beam of 50 keV ± 2.5 keV energy, which then passes through a multi-cell S-band RF cavity, accelerating the electrons to a final average energy of 6 MeV. Subsequently, the beam interacts with a tungsten plate downstream, generating gamma rays. An integrated simulation system consisting of specialized software for different study aspects has been developed. Poisson Superfish and CST Studio were used for RF cavity design, Travel for beam dynamics analysis, and Geant4 for simulating electron-gamma conversion and tracking. All beam properties were exported between codes in such a way that the particles position, energy, and RF phase dependency were preserved throughout. This work aims to define the realistic limits of the electron beam quality in RF electron linear accelerators for gamma irradiation.

Interaction between (H2, CO2) and Cu5Zn8 to study the effect of catalytic properties using DFT

Mon, 01 Sep 2025 00:00:00 +0000

The model of CuZn as a metal alloy is obtained from representative experimental data of the catalyst for the transformation of CO2 to methanol, the surface plane (111) selected from the unit cell detecting by the position of Zn and Cu exhibits interesting regions ("A","B"). From a fundamental point of view, the interaction allows us to study the participation of Zn and Cu followed by CO2 and H2 for different separation distances. The molecular interaction by the energy and optimization calculations obtained results that determine important aspects to explain bond length changes of the H H and O C O. Energy values identify potential areas for Zn or Cu where they exhibit attraction, repulsion, and the minimum, in molecules of H2 and CO2 . The interaction of the hydrogen molecule with the surface in both regions shows bond length changes with a dissociative effect that reaches 0.921 Å by the direct interaction of Zn and Cu. The CO2 interacting with Zn and Cu reaches a maximum elongation of 1,309 Å. The interaction with H2 followed by CO2 in the presence of the surface has physicochemical effects when increased to 3 hydrogen molecules showing the catalytic phenomenon. The calculations use a level of DFT theory with a GGA approximation and DNP base functions to describe the electronic and structural properties.

Impact of A-site cation substitution on the properties of pinel AY₂O₄ (A = Cd, Zn): A first-principles investigation

K. Hocine, Y. Guermit, A. Chaabane — Mon, 01 Sep 2025 00:00:00 +0000

This study presents a comprehensive first-principles investigation of the structural, electronic, magnetic, elastic, thermodynamic, and optical properties of spinel-type compounds CdY₂O₄ and ZnY₂O₄ using density functional theory (DFT) within the full-potential linearized augmented plane wave (FP-LAPW) method. Structural optimization, performed through Murnaghan equation of state fitting and internal atomic relaxation, reveals that both compounds favor a nonmagnetic normal spinel configuration as their ground state. Electronic band structure calculations using PBE-GGA and TB-mBJ functionals demonstrate that both ZnY₂O₄ and CdY₂O4 are direct band gap semiconductors, with wide band gaps ranging from 4.86 to 4.93 eV. Elastic constants confirm mechanical stability, with CdY₂O₄ exhibiting ductile behavior and ZnY₂O₄ displaying higher stiffness but slightly brittle characteristics. Thermodynamic properties, evaluated via the quasi-harmonic Debye model, indicate that both materials maintain structural integrity up to 1200 K and 20 GPa, with ZnY₂O₄ showing superior thermal stability. Optical analyses reveal strong ultraviolet absorption, high transparency in the visible range, and low reflectivity, positioning these materials as promising candidates for UV optoelectronic applications, including UV filters, transparent conductive coatings, and window layers in tandem solar cells. The results highlight that cation substitution at the A-site (Cd²⁺ versus Zn²⁺) significantly influences the mechanical, thermal, and optical properties, making CdY₂O₄ and ZnY₂O₄ attractive for next-generation photovoltaic and photonic devices.

A regularization strategy for inverse source problems with applications in optics

Mon, 01 Sep 2025 00:00:00 +0000

In this work, we provide a stable algorithm for the inverse source problem where the region corresponds with a circle centered on the origin. The algorithm is obtained using an operational equation, which is ill-posed in the Hadamard sense due to the following points: firstly, many sources produce the same measurement and, secondly, due to the presence of numerical instability. If the operational equation is restricted to the Hilbert space of harmonic functions, the inverse source problem's uniqueness is guaranteed. The algorithm considers two regularization parameters to handle the numerical instability: the Tikhonov regularization parameter and the term N, where the series expansion is truncated. To illustrate the proposed algorithm, we developed one numerical example.
Furthermore, we apply the algorithm to solve one inverse optical problem associated with the Intensity Transport Equation when the intensity distribution is considered almost uniform for the case in which the wavefront, which propagates in the direction of the optical axis, is considered within the paraxial approximation. The case where the source is not harmonic has no unique solution without a priori information. This work presents the case where the source belongs to functions that take two values. For this type, it is possible to recover the source completely. We give examples of the same application considering two cases for the source of the right side of the Intensity Transport Equation: when the source is a harmonic function and when it belongs to the above-mentioned type.

An exactly solvable tight-binding billiard in graphene

D. Condado, E. Sadurní — Mon, 01 Sep 2025 00:00:00 +0000

A triangular graphenic billiard is defined as a planar carbon polymer in the Hückeloid approximation of π−band electrons. It is shown that the equilateral triangle of arbitrary size and zig-zag edges allows for exact solutions of the associated spectral problem. This is done by a construction of wave superpositions similar to the Lamé solution of the Helmholtz equation in a triangular cavity, revisited by Pinsky. Exact wave functions, eigenvalues, degeneracies, and edge states are provided. The edge states are also obtained by a non-periodic construction of waves with vanishing energy. A comment on its connection with recent molecular models, such as triangulene, is given.

Impact of atomic initial conditions on nonclassicality of the light in the ladder-type three-level Jaynes-Cummings model

Mon, 01 Sep 2025 00:00:00 +0000

We explore the interaction between a three-level atom and a single-mode quantized cavity, known as the three-level ladder-type Jaynes-Cummings model. By employing the exact solution of the Schrödinger equation, we investigate how the initial conditions of the atom influence the occupation probabilities of the atomic energy levels, average photon number, and the nonclassicality of light, assessed through the Mandel Q(t) parameter and the Wigner function. Our findings are rigorously validated through comprehensive numerical simulations, ensuring robust and consistent outcomes.

Spatial phase filtering approach for the instantaneous measurement of the degree and angle of linear polarization employing a pixelated polarization camera

Mon, 01 Sep 2025 00:00:00 +0000

We present a novel phase-based filtering algorithm designed to retrieve the Degree of Linear Polarization (DoLP) and Angle of Linear Polarization (AoLP) by leveraging the intrinsic properties of a pixelated polarization camera. Unlike conventional intensity-based filters, our approach utilizes complex phase values to estimate polarization parameters, offering a flexible and computationally efficient alternative. Each point is treated as an independent measurement, dependent solely on the kernel size, which enables the potential for real-time processing. Experimental and simulation evaluations under Gaussian noise conditions validate the robustness of our approach, demonstrating a high degree of consistency with standard methods. The ANOVA analysis results reflect this consistency across datasets, as indicated by the sum of squares (SS), mean squares (MS), and F-statistic values. This reinforces the reliability of the proposed algorithm and highlights its practical applicability in noise-affected environments. Our findings suggest that the proposed method provides a stable and adaptable solution for polarization parameter extraction, making it well-suited for applications in fields such as biomedical imaging, remote sensing, and industrial inspection, where real-time performance and noise resilience are critical.

Classification of streaming platform images using local binary patterns and machine learning algorithms

J. Álvarez-Borrego, E. Guerra-Rosas, L. F. López-Ávila — Mon, 01 Sep 2025 00:00:00 +0000

This research has developed an effective multi-class classification model for images from streaming platforms. Texture features were extracted from the images and used with machine learning algorithms. Two datasets were employed: ’mosaics’ comprising 153,488 images across 14 classes and ’descriptors’ containing 33,471 images across 11 classes. All images had a resolution of 1280 × 720 pixels. The local binary pattern (LBP) technique encoded the local texture structure into 59-element feature vectors for each image. Ten algorithms were trained and evaluated on these vectors for each dataset, including support vector machines (SVM) with linear, polynomial, and Gaussian kernels at various scales, as well as ensemble methods like boosted trees, bagging, discriminant analysis, and k-nearest neighbors in subspaces. Training and validation were done via 30 random splits to mitigate bias. Performance metrics like accuracy, sensitivity, specificity, precision, and F1-score were computed per class. The SVM classifier achieved top mean performance: 0.998952 accuracy, 0.992528 sensitivity, 0.999438 specificity, 0.988132 precision, and 0.990280 F1-score. The results validate the proposed LBP feature extraction and machine learning methodology for effectively classifying images across streaming platforms.

Optical solitons and parameters stability of the coupled system in magneto-optical waveguides

Ning-He Yang — Mon, 01 Sep 2025 00:00:00 +0000

In this paper, optical solitons propagation in magneto-optical waveguides which is modeled by a coupled nonlinear Schrödinger equation system. A series of wave propagation patterns are given, including solitary wave solutions, periodic solutions and singular solutions. In addition, the physical realization of the optical wave modes is carried out under certain parameter values. In particular, the parameters stability of these optical wave modes is obtained.

Analysis of errors in corneal topography evaluation caused by distortion aberration in the camera lens of a cone corneal topographer

Mon, 01 Sep 2025 00:00:00 +0000

We study the effects on corneal topography when the topographer camera is affected by distortion aberration, causing a nonuniform magnification in the image recorded by the camera sensor. As a result, images present a size change which could mislead the interpretation of the vertex position of the anterior corneal surface. Images numerically generated and distorted using the Seidel's aberrations are used to carry out the analysis. According to the results presented in this paper, while the reconstruction algorithm accurately recovers the central region of the surface, there are pronounced deviations between the retrieved surface and the actual surface towards the periphery. These deviations could lead to the underestimation or overestimation of the parameters associated with the base surface for a contact lens, affecting the correction of refractive errors such as myopia, hyperopia or astigmatism. Moreover, if the corneal topography provided by a topographer affected by distortion aberration is used for corneal reshaping via laser ablation, the refractive errors might be overcorrected or undercorrected. Thus, this paper highlights the importance of performing a proper calibration procedure for the distortion aberration of the corneal topographer camera, in order to reliably recover an accurate corneal topography.

A non-Newtonian approach to electromagnetic curves in optical fiber

Aykut Has, Beyhan Yılmaz — Mon, 01 Sep 2025 00:00:00 +0000

The investigation within this article delves into the non-Newtonian geometric attributes exhibited by a linearly polarized light wave along an optical fiber within the framework of the 3D multiplicative Riemann manifold, employing multiplicative derivative and integral. While conducting this research, the unique arguments of multiplicative analysis (angle, norm, distance, etc.) are used. Within this context, the optical fiber is presumed as a one-dimensional entity embedded in the 3D Riemannian space, establishing a connection between the linearly polarized light wave's evolution and the geometric phase. Consequently, a novel form of the multiplicative geometric phase model is formulated, integrating the principles of multiplicative calculus. Additionally, the concept of multiplicative magnetic curves generated by the electric field $\e$ is introduced. Notably, this study stands out due to its unique utilization of multiplicative derivatives and integrals in the computational processes. The article culminates by presenting illustrative examples consistent with the outlined theoretical framework, accompanied by visual representations. The distinctiveness of this research lies in its departure from conventional methodologies, incorporating multiplicative calculus into the calculations. Remarkably, multiplicative computing demonstrates its applicability across diverse domains including physics, engineering, mathematical biology, fluid mechanics, and signal processing. The pervasive use of multiplicative derivatives and integrals signifies their profound significance as a novel mathematical approach, contributing substantially to problem-solving methodologies across various scientific disciplines.

Enhancing the electronic properties of graphimine through transition metal substitution: A DFT Study

S. Farqad Enais, M. L. Jabbar — Mon, 01 Sep 2025 00:00:00 +0000

This research aims to study the novel graphimine material by highlighting its physical and chemical properties. To enhance these properties, some atoms in the compound were replaced by transition metals. This replacement leads to new interactions between the bonds of the added metal atoms and the atoms of the original compound, which contributes to significantly improving the electronic properties of the compound due to the changed distribution of charges within the structure. Modeling of the graphimine structure as well as the resulting compounds after adding atoms of transition metals such as Sc, Ti, Fe, Ni, Cu, and Nb were performed. The best optimization of the compounds was achieved using density functional theory (DFT) and based on the B3LYP and 6-31G basis set. After that, the various properties of the compounds, such as charge distribution contours, energy gap, hardness, softness, and infrared spectrum, were calculated. The results indicate that the energy gap has been reduced in all compounds compared to the energy gap of the original compound, reflecting the effect of the modifications introduced on the electronic properties of the compound. Therefore, the energy gap values fall within the range of semiconductors, which gives great importance to these compounds, especially in electronic applications such as catalysts and solar cells.

Role of deuteron beam Incidence on the neutron-free fuel pellet using helium catalyzed process in enhancing energy gain

S. N. Hosseinimotlagh, A. Shakeri — Mon, 01 Sep 2025 00:00:00 +0000

Fast ignition is recognized as a potential method to achieve the high energy-gain target performance required for commercial inertial confinement fusion. In this article, the deuteron beam driven causes fast ignition, which provides not only the ignition spark of the "hot spot" but also the "bonus" fusion energy through reactions within the target. We have estimated the energy deposited contribution as a bonus resulting from the fusion reactions that occurred based on calculations using a modified energy enhancement factor. To achieve this goal in the ICF plan, the use of pure fuel is impractical due to the excessive need for energy driven. Therefore, a small amount of D-T fuel is necessary as a "igniter".Since the reaction does not produce any neutrons and fuel sources for the D-D reaction are abundant, it is expected that these reactions can be used in advanced fuel fusion reactors. The main interest in the helium-catalyzed process, in which T and produced by fusion are recycled, is mainly due to the fact that deuterium fuel has essentially unlimited resources on Earth. In the calculation method of this article, without using helium catalyzed process, the fusion gain gradually increases with increasing temperature and reaches a maximum value of about 20 at a temperature of 190 keV, while using helium catalyzed process, it gradually increases with increasing temperature and reaches a maximum value of about 110 at the same temperature

Physical principles adapted to clinical practice for a theoretical smoke evacuation device in laparoscopic surgery

V. J. Ovejero Gómez, V. Ovejero Bermúdez, C. Sainz Fernández — Mon, 01 Sep 2025 00:00:00 +0000

Suboptimal visualization of the surgical field due to smoke generated in any laparoscopic technique, along with the impact on healthcare workers exposed to its toxic particles, has prompted the marketing of various suctioning devices. A limited information on physical basis of these systems has encouraged us to develop a theoretical model that enables a basic experimental recreation of smoke evacuation in pneumoperitoneum. The cooling effect of the abdominal cavity due to the circulation of insufflated gas and variations in its composition resulting from the operative use of electrocoagulation are the primary factors that lead to the collapse of a circuit designed under laminar flow conditions when an increase in suction flow rate is required to preserve surgical vision. The pressure difference generated in the circuit by tripling its flow induces a change in flow regime, preventing collapse without the need for excessive gas renewal. An analysis of the cross-sectional radius, tube wall composition and absolute roughness of endoluminal surface are conducted to assess performance of our model. Behavior of fluids in different pathophysiological situations is studied by Science undergraduates, but instructional simulations in the laboratory often fail to transfer this knowledge into the design of practical devices that correlate the statics of an inert material with the variability of a biological system. This theoretical device has been crafted to encourage students interested in the experimental patterns for biomedical applications related to fluid behavior and turnover during minimally invasive procedures involving the peritoneal cavity.

Modeling the link between carbon emissions and ocean acidification using a Lotka-Volterra dynamical system

L. F. Mendoza-Mendoza, I. Álvarez-Ríos, F. Z. C. León-Altamirano, F. S. Guzmán — Mon, 01 Sep 2025 00:00:00 +0000

We study the possibility that the dynamics of carbon emissions and aragonite saturation in sea water can be modeled with a non-linear coupled system of two Ordinary Differential Equations. In total, there are seven parameters plus two initial conditions that we fit in order to adjust experimental data. For the fitting, we use two independent methods: Genetic Algorithms and Monte Carlo Markov Chains, both useful at fitting in high-dimensional parameter spaces. The data for the carbon emissions we deal with is obtained from several sources dedicated to monitoring the changes in these emissions over time. We calculated aragonite saturation using a combination of carbon chemistry measures from two stations. Our findings show that with this combination of ODEs and the fitting methods chosen, these two phenomena can be reproduced within an 8% error.

Properties and baroclinic instability of stratified thermal upper-ocean flow

F. J. Beron-Vera , M. J. Olascoaga — Mon, 01 Sep 2025 00:00:00 +0000

We study the properties of, and investigate the stability of a baroclinic zonal current in, a thermal rotating shallow-water model, sometimes called Ripa's model, featuring stratification for quasigeostrophic upper-ocean dynamics. The model has Lie--Poisson Hamiltonian structure. In addition to Casimirs, the model supports weak Casimirs forming the kernel of the Lie–Poisson bracket for the potential vorticity evolution independent of the details of the buoyancy as this is advected under the flow. The model sustains Rossby waves and a neutral model, whose spurious growth is prevented by a positive-definite integral, quadratic on the deviation from the motionless state. A baroclinic zonal jet with vertical curvature is found to be spectrally stable for specific configurations of the gradients of layer thickness, vertically averaged buoyancy, and buoyancy frequency. Only a subset of such states was found Lyapunov stable using the available integrals, except the weak Casimirs, whose role in constraining stratified thermal flow remains to be understood. The existence of Lyapunov-stable states enabled us to a priori bound the nonlinear growth of perturbations to spectrally unstable states. Our results do not support the generality of earlier numerical evidence on the suppression of submesoscale wave activity as a result of the inclusion of stratification in thermal shallow-water theory, which we supported with direct numerical simulations.