Polytechnic University of Queretaro

Objective. This paper describes a new method for measuring human bone density based on the measurement of bone electrical conductivity (BEC) using the well-known technique: electrical impedance tomography (EIT).Approach. The hypothesis is that BEC is directly related to bone mineral density. The proposed method consists of measuring the EIT, and then obtaining the conductivity values of the bones, and take this value to associate this one to a level of porosity. A model of skin, muscle, and bone was developed using computer simulation to vary the porosity in bones and obtain an inverse model in the form of an equation to measure three levels of porosity.Main results. The behavior of different porosity levels was simulated, and impedance tomography was applied; it is shown that electrical conductivity varies according to bone porosity. A relationship was subsequently obtained between the measurement of conductivity and bone density, creating a new non-invasive method for possible application to early detection of osteoporosis.Significance. This is a novel, non-invasive method for possible application on the early detection of osteoporosis at three different levels of bone porosity.

This study presents a numerical and experimental analysis of vertical-axis Cycloidal rotors (RC) versus Savonius rotors (RS), with and without coupling to a Gorlov rotor (RG), designed to operate under low wind speed conditions of 2.5 m/s. Using transient Computational Fluid Dynamics (CFD), numerical mesh stability was evaluated as a function of rotor power, achieving convergence with 8,199,923 nodes and a stable angular momentum after 10 s. In the experimental phase, electrical characterization was conducted by coupling the rotors to a direct current generator, allowing for the determination of the optimal electrical load as a function of rotational speed (RPM). The results show that electrical power output and power coefficient (Cp) increased with rotational speed, reaching a maximum of 39.22 mW and Cp = 0.126 for the Cycloidal rotor (RCθR45), which exhibited the best overall performance. When coupling a Gorlov rotor with a torsion angle of 90° (RGθG90), maximum power of 52.45 mW and Cp = 0.168 were obtained for the hybrid configuration RC,θR0-RGθG90, confirming the aerodynamic and electrical performance improvement due to geometric coupling compared to a standalone Savonius rotor. The comparison between the numerical and experimental results showed consistent trends in Cp values, with slight deviations attributed to friction and alignment effects during physical testing. This study proposes an integrated methodology in renewable energy technologies that combines 3D transient CFD simulation with experimental characterization under variable electrical load conditions to determine the optimal operating power of novel Cycloidal rotors for low-wind-speed applications.

En este estudio se desarrolló en una investigación documental, descriptiva y de campo, aplicando encuestas diseñadas a partir de los factores críticos identificados en la literatura para la implementación de Lean Manufacturing y Economía Circular. La muestra incluyó 40 empresas localizadas en cuatro parques industriales del estado de Querétaro, parte de los 49 existentes en municipios como El Marqués, Querétaro, Colón, Corregidora, San Juan del Río y Pedro Escobedo, pertenecientes a sectores clave como automotriz, plástico, alimentario, agrícola, entre otros. Los hallazgos evidencian un marcado interés empresarial en incorporar estas metodologías y transitar hacia modelos operativos sostenibles. Sin embargo, persisten barreras relevantes asociadas con la cultura organizacional, la resistencia al cambio y las limitaciones en programas de formación. La integración de Lean Manufacturing y Economía Circular se perfila como una estrategia esencial para fortalecer la competitividad, optimizar procesos y reducir los impactos ambientales en la región, aportando un marco de referencia sólido para la gestión industrial con más de dos décadas de experiencia aplicada.

ABSTRACT Molybdenum chalcogenides are one of the most studied layered materials. They have hexagonal symmetry in the single layer case as many other van der Waals materials. Thus, they can serve as a model for the analysis of many physical properties, in particular the phonon modes, the appearance of new low wave number modes when going from the single layer to the bulk, the existence of a flexural acoustic mode and the grouping of the optical modes into pairs whose difference comes from the interlayer coupling. In this work, to address some of these points, we have calculated the phonon dispersion of MoS , MoSe , and MoTe in bulk and in a single layer using Density Functional Perturbation Theory and discuss the evolution of the energy branches along the different directions of the Brillouin zone. The calculated values are in very good agreement with Raman data reported in the literature. We have also calculated the static and optical dielectric constants, as well as the reflectance, which has been compared with available infrared reflectance data available in the literature. Finally, we discuss the activity of the optical modes in the bulk and single layer case.

The purpose of this study was to identify the perception that micro and small enterprises (MSEs) have regarding the use of marketing and market analysis tools, as well as their functionality. Therefore, it is hypothesized that less than 50% of the MSEs in Mexico use various marketing and market analysis tools. The method used was deductive and the research design was carried out with a quantitative and descriptive approach, due to the fact that the purpose of the study was to identify the perception that these companies have regarding the use of market analysis and marketing tools. Among the results obtained, it is observed that approximately more than 50% agree and strongly disagree that they perform market analysis activities focused on identifying the strengths and weaknesses of the competition, as well as knowing the needs and preferences of customers. It is concluded that they carry out market analysis activities focused on identifying the strengths and weaknesses of the competition, as well as knowing the needs and preferences of the clients; as well as, using pricing according to the client, creating and developing the brand, selling their products or services to the end user and carrying out advertising and promotion activities, as well as customer loyalty. However, it is observed that they consider that it is easy for new companies and substitute products to emerge.

The electromagnetically driven magnetised spherical Couette flow is studied experimentally, theoretically and numerically in the laminar regime. The working fluid, Galinstan, is contained in the spherical gap between two concentric spheres at rest. The electromagnetic stirring is primarily generated due to the interaction of a direct current, which is injected through two ring-shaped electrodes located at the equatorial zone of each sphere, and a dipolar magnetic field produced by a permanent magnet located inside the inner sphere. The flows were explored experimentally for a Reynolds number ranging from 450 to 2230 and a Hartmann number of 240. Ultrasound Doppler velocimetry and particle image velocimetry were used to characterise the flow. For low Reynolds numbers, given the symmetry of the problem, a one-dimensional analytic solution is obtained in the equatorial plane from the magnetohydrodynamic equations. The analytical solution reproduces the main characteristics of the flow. In addition, a full three-dimensional numerical model is able to reproduce both the analytical solution and the experimental measurements. To the best knowledge of the authors, this is the first time experimental results of the magnetised spherical Couette flow have been reported with electromagnetic forcing using a liquid metal as the working media.

Under current conditions of economic transformation, creative industries are gaining strategic importance for the development of the state. The business reputation of economic entities in this field is becoming not only a tool of competitive struggle but also a crucial factor in building trust among consumers, partners and investors. The specific nature of forming the reputation in creative business is associated with brand personalisation, public visibility, rapid reputational dynamics and the necessity of innovation. The article analyses key directions of forming the business reputation of representatives of creative business and identifies the factors that ensure its sustainability. The conclusions presented may be useful for both scholars and practitioners in the field of cultural entrepreneurship. The objective of this study was to substantiate the peculiarities of forming the business reputation of economic entities in creative industries as a key factor of their competitiveness, sustainable development and economic growth. Representatives of the business environment in creative industries of the country are the object of research. The aim of the research is to identify and systematise key features of forming the business reputation of economic entities in creative industries, taking into account their specific characteristics and their impact on business success. The methodological basis of the study includes: the works of Ukrainian and international scholars on various aspects of forming the business reputation of economic entities for both classical and creative enterprises; statistical data from the official website of the State Statistics Service of Ukraine; and a set of general scientific and specific research methods (analysis and synthesis, comparative method and system approach). Based on the research results, the paper identifies the features of forming the business reputation in creative enterprises within the directions typical of classical business (product quality; corporate social responsibility; financial stability; employer branding) and substantiates specific factors influencing the formation of the business reputation of creative business entities (individuality of the brand and personality; public presence and visibility of the brand; reputational sensitivity; innovativeness and flexibility of thinking of the artist or creative team). The scope of application of the research results encompasses educational activities (for the training of specialists in the sectors of creative entrepreneurship, marketing and cultural studies); practical implementation in creative business (as a methodological guideline for developing reputation management strategy); government and regional policies (for the development of programmes to support creative entrepreneurship); and scientific research (as a basis for further studies on business reputation formation in the creative economy). The findings of the study will enable Ukrainian creative businesses to identify effective areas of activity that contribute to build a positive image and consumer trust, and to develop a reputation strategy adapted to the specific characteristics of the creative sector, including the public positioning of a personal brand

Visible-light-active photocatalytic heterojunctions based on nanostructured β-Bi2O3/Cu2O semiconductors were successfully coupled by high-energy ball milling, exhibiting enhanced charge carrier separation, transfer, and reaction properties. The optical, structural, and photoelectrochemical properties of the catalysts and their heterojunctions were analyzed to evaluate the coupling efficiency. The optimal stoichiometric ratio of (1 – x)β-Bi2O3/xCu2O (x = 25, 50, and 75 wt %) and the milling time significantly influenced the optical properties, including photoluminescence (PL). A notable decrease in PL intensity was observed for the heterojunction with x = 25%, compared to that of the single semiconductors. This effect was further enhanced with increasing milling time, which is attributed to the mechanical energy input. The formation of nanosized mixed-phase transition heterojunctions was confirmed by scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), and energy-dispersive spectroscopy (EDS). Structural characterization revealed increased lattice parameters and reduced crystallite size due to mechanical milling. Milling-induced structural deformations led to decreased PL intensity and band gap energy. Photocatalytic efficiency was the highest for heterojunctions prepared with shorter milling times; longer milling times introduced structural defects that reduced photocatalytic performance. Flat band potential (EFB) analysis identified a p–n junction with staggered band edge alignment. The heterojunction, which was milled for 60 min, exhibited an absorption range extending up to 1.84 eV. Notably, the 75β-Bi2O3/25Cu2O sample milled for 5 min achieved 98% photocatalytic efficiency under visible light irradiation. Mechanical milling is a simple, inexpensive, one-step process for fabricating nano-sized heterojunctions with well-mixed interfaces that enhance charge carrier separation. While structural defects are detrimental in excess, they can enhance photocatalytic activity at optimal concentrations.

Every time the proper functioning of the vehicles must be guaranteed, as well as safety and efficiency. To achieve this, some expensive solutions are used, with few connectivity options and that fail to meet consumer demand. This paper presents a low-cost hardware system for the design of a real-time communication protocol between the electronic control unit (ECU) of a vehicle and a remote server based in a embedded system. A dual tone multi-frequency (DTMF) approach is implemented, so error codes (DTCs) are always available on a unit equipped with this system. The vehicle-to-infrastructure (V2I) communication protocol through voice channels is provided by cellular technology infrastructure, in which primary information is shared to monitor vehicles. With real-time data transmission, communication is established through a voice phone call between the vehicle’s ECU and the destination server, communicating the DTC codes. The system shows that the communication protocol has an effectiveness of 78.23%, which means that with the use of 2G technology, which is active and operating in many regions, it allows the information with the data to be received by the receiving user. Through this implemented system, it is ensured that if a vehicle suffers an accident or stops due to a mechanical failure in a region where there is no cellular technology coverage, information or a message can be sent so that through communication the rescue can be carried out using an cellular technology coverage.

The automotive industry has recently adopted multicore processors and microcontrollers to meet the requirements of new features, such as autonomous driving, and comply with the latest safety standards. However, inter-core communication poses a challenge in ensuring real-time requirements such as time determinism and low latencies. Concurrent access to shared buffers makes predicting the flow of data difficult, leading to decreased algorithm performance. This study explores the integration of Logical Execution Time (LET) and Time-Division Multiple Access (TDMA) models in multicore embedded systems to address the challenges in inter-core communication by synchronizing read/write operations across different cores, significantly reducing latency variability and improving system predictability and consistency. Experimental results demonstrate that this integrated approach eliminates data loss and maintains fixed operation rates, achieving a consistent latency of 11 ms. The LET-TDMA method reduces latency variability to approximately 1 ms, maintaining a maximum delay of 1.002 ms and a minimum delay of 1.001 ms, compared to the variability in the LET-only method, which ranged from 3.2846 ms to 8.9257 ms for different configurations.