bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gamma/hadron discrimination at high energies through the azimuthal fluctuations of air shower particle distributions at the ground
Authors: Conceição R. , Gibilisco L. , Pimenta M. , Tomé B. 
Published: October 2022

Abstract
Wide field-of-view gamma-ray observatories must fight the overwhelming cosmic ray background to identify very-high-energy astrophysical gamma-ray events.
This work introduces a novel gamma/hadron discriminating variable, LCm, which quantifies the azimuthal non-uniformity of the particle distributions at the ground. This non-uniformity, due to the presence of hadronic sub-showers, is higher in proton-induced showers than in gamma showers. The discrimination power of this new variable is then discussed, as a function of the air shower array fill factor, in the energy range 10TeV to 1PeV, and compared to the classical gamma/hadron discriminator based on the measurement of the number of muons at the ground. The results obtained are extremely encouraging, paving the way for the use of the proposed quantity in present and future large ground-array gamma-ray observatories.
Improvement to the Fractal Adsorption Isotherms of Porous Surfaces
Authors: Morales J , Martínez A 
Published: October 2022

Abstract
The theoretical and experimental Adsorption Isotherms (AI) are essential for the study of surface area and porous structure in solid materials. Also, the fractal dimension characterizes the roughness of a surface which means that a smooth surface has dimension two, whereas that of a highly rugged surface approaches to three. So, although there are several methods to evaluate fractal adsorption isotherms the Fripiat proposal can be considered as the generalization of the Brunauer-Emmett-Teller (BET) formulation for homogeneous surfaces because it contains, as particular case, the classical BET relationship for fractal dimension D=2. However, in the fitting of experimental Nitrogen adsorption data with the Fripiat approach is compulsory to use the BET classical formula for the calculation of the C constant and the monolayer volume. Thus, in order to overcome such constraint, in this work is presented an alternative treatment of fractal adsorption isotherms as applied to porous surfaces. The proposal is based on a relationship between the physical adsorption in homogeneous and inhomogeneous surfaces followed to the assumption that the emerging series are well correlated with polynomials. i.e. we propose an improved formulation to the fractal dimension which is solved by lineal regression avoiding the use of classical parameters. As expected, our proposition contains as particular cases the BET and Fripiat’s formulas. As an example of the usefulness of our proposal, we consider the experimental data of isothermal adsorption obtained with Al2O3 that were synthesized via sol-gel at various temperatures; the results are in good agreement with the fractal dimension evolution and with the microporous and mesoporous structure of the materials under consideration.
Thermal analysis of a solar still through CFD
Authors: Flores M , Chávez S , Terres H , Lizardi A , Lara A 
Published: October 2022

Abstract
Present work shows the results of the thermal performance of a single-slope solar still under different tilt angles of the glass cover, using numerical simulation through CFD. Simulations were carried out using Computational Fluid Dynamics for glass-cover tilt angles of 10°, 20°, 30°, and 40°. For each angle, distributions of temperature, density and velocity of the fluid were obtained. Besides, the convective heat transfer coefficient between the basin and the fluid was calculated. As a result, it was found that the water temperature and density differences between the basin and the glass cover increase as the tilt angle also increases. Furthermore, the fluid flow follows a laminar regime for the 10° and 20° angles, while for the tilt angles of 30° and 40°, flow obeys a turbulent behavior. Finally, simulation results show that heat transfer coefficient increases as a function of the tilt angle, ranging from 2.45 W/m2-K to 3.29 W/m2-K.
Remote control and monitoring of a hydraulic machine
Authors: Aragón González G , Barragán Santiago I , Bautista Godínez I , Becerra Martínez P , Delgado Román O , León Galicia A , Manrique Garay J 
Published: October 2022

Abstract
An electronic system based on an open source programmable board was designed and tested, for remote control and monitoring of a fluid power machine. To satisfy the requirements for remote two-way communication between the machine and the user interface, a connection must be established via the Internet. The Arduino Uno Wi-Fi Rev 2 board is designed to connect wirelessly to a local network. To transmit the data between the board and the graphical interface, on a device that is on an external network, a MQTT broker was generated on an AWS server. A program receives the information from the sensors, sends it to the user interface, makes logical decisions, processes the information of control orders, and establishes the protocols to govern the machine. The electronic system was tested with a mobile hydraulic crane. Four variables were selected to control and monitor the crane performance: the load position, the current demanded by the electric motor, the flow supplied by the hydraulic pump and the presence of mechanical pins to lock or release the hydraulic linear actuator. Two tests were conducted to control the machine remotely, one within the same location and the other from Berlin, Germany. It was possible to use the open source board for connecting with the user interface generated with Node-RED via MQTT protocol and control and monitor the machine performance.
On the microstructure of as-cast Zn-based ternary alloy
Authors: Domínguez Contreras L A , Ramírez Ledesma A L , Juárez Islas J A 
Published: October 2022

Abstract
There are limited investigations of the alloys that involve peritectic reactions, due to its complexity. In the present study, casting experiments in a steel mold of square section were carried out in order to show a formal characterization of a zinc-based ternary alloy that has a complex microstructure. The results obtained confirm that instead of the typical structure of primary phase surrounded by peritectic phase on Zn-Ag peritectic systems, a AgZn dendritic phase, a mixture of two solid solutions (η-Zn and AgZn3), precipitates, and a eutectic-like lamellar structures with atomic ratio of Zn/Ag/Mg ~95/3/2 were observed.
Control of a 2 DOF Elbow Prosthesis prototype
Authors: Hernández Cerero R , Leal Naranjo J A , Torres SanMiguel C R 
Published: October 2022

Abstract
This paper presents a 2 DOF elbow prosthesis design and its control, which includes developing the mechanism, adapting a torsional spring for the flexo-extension movement, and a crown pinion transmission with two torsional springs pronosupination movement. In addition, this prototype has planned an elbow joint control method. The control has been obtained using the kinematic of a pendulum with a torsional spring, where the model comes with a set of dynamic simulations to determine how feasible the proposed mechanism is, and the torque needed for daily activities performance. The results show the physical and kinematic characteristics of the designed system.
Discrete control of transfemoral prostheses for human walking with magnetorheological compensation
Authors: Zuly A Mora P , Vásquez S M , Valencia César H , Carreño Zagarra J J , Becker Marcelo , Ospina Henao P A 
Published: October 2022

Abstract
This abstract presents the modeling and control of a transfemoral prosthesis with magnetorheological compensation. Initially, leg modeling is shown by the formulation of the Euler-Lagrange motion equations and the inclusion of the modified Bouc-Wen model for the magnetorheological damper. Subsequently, the linealization of these models is presented using the Taylor series approximation. For the design of the controller is used the analysis of the geometric place of the roots. The simulation results of the control system indicate that the prosthesis is capable of accurately following established joint references and effectively rejects external disturbances.
Analytical velocity hodograph of projectile motion under polynomial drag
Authors: Hernández Saldaña H 
Published: October 2022

Abstract
Velocity hodographs are of importance in weather analysis. A historically important case is the hodograph in the Kepler problem. Here, we explore the analytical solutions for the velocity hodograph for the projectile trajectories under a polynomial, in velocity, hydrodynamic dissipation. General solutions in terms of hypergeometric functions are found for odd powers in monomial terms. The even powers have analytical hodographs but we do not find a general expression for them. For completeness we include the constant or Coulomb case, as well as its sum with the linear and quadratic cases. Both shown explicit solutions as functions of the angle. Usually the linear case is discussed in textbooks and articles, here we find that more general cases admit analytical solutions, even when the position and time cannot be obtained explicitly and they need of numerical integration. Furthermore, motion with constant and, additional linear or quadratic drag could be used to design new university lab experiments.
Study and characterization of components fabricated in a 3D printer
Authors: Bautista Hernández A , Villalobos Mendoza B , Pérez Tijerina E G , Aguirre Aguirre D 
Published: October 2022

Abstract
In this work, we present the characterization of a Form 3 Stereolithography (SLA) FormLabs 3D printer which will be used for the fabrication of optical components. The characterization consisted of the measurement of the refraction index, absorbance & transmittance values, as well as geometrical parameters like radius of curvature, thickness, roundness, and angles. This study proved that with the Form 3 SLA additive technology components with good quality that meet the design parameters can be fabricated.
In-vivo blood velocity measurement by multiple tpg encoding and maximum likelihood spectral estimation
Authors: Benitez-Read E E 
Published: October 2022

Abstract
The purpose of this paper is to show the application of the multiple velocity encoding (MVEnc) and the maximum likelihood velocity estimation (MLVEst) methods to the measurement of velocity of blood in the popliteal artery of a live human knee in presence of stationary tissue (spins). These methods were developed before by the author of this paper. Blood velocity images of the same popliteal artery were obtained in order to compare them with the ones obtained using other methods. Additionally, they can be used to obtain true angiographic images of any vessel.
Didactic model of the diode with Finite Element Method
Authors: Aya Baquero H 
Published: October 2022

Abstract
The union of two extrinsic semiconductors, one of them doped with donor impurities and the other with acceptor impurities, constitutes what is called the diode. In this paper we present a didactic model of diode, from which its electrical characteristics can be extracted, such as the structure of energy bands, the characteristic curve of current voltage, etc. To achieve this purpose the Finite Element Method (FEM) was used. In essence, the MEF is a method that allows numerically approximate the solution of partial differential equations. It is well known that, except in very particular cases, obtain analytical solutions of such equations is impossible, and the only possibility is to find approximate solutions. This model is implemented in the search for new strategies and methods of teaching concepts related to electronic devices, such as diodes, transistors, light-emitting diodes, quantum devices, etc.
Adsorption of formaldehyde on titanium decorated graphene
Authors: Arellano J S 
Published: October 2022

Abstract
This work presents results for the adsorption of the formaldehyde molecule on one Ti-graphene layer formed by 32 carbon atoms. Calculations are done under the DFT (density functional theory) scope as implemented in Quantum espresso computer code. After the equilibrium Ti position above a pristine graphene layer has been obtained, it is added the CH2O molecule to obtain the equilibrium configuration of the entire system. Previously also the equilibrium configuration of the formaldehyde molecule and the graphene layer was obtained. Ti atom makes bonds with both, carbon and oxygen atom of the formaldehyde molecule. Adsorption of CH2O molecule above graphene and Ti-graphene with one and two carbon vacancies is discussed.
Structure and diffusion of ions in layers of dielectric interfaces
Authors: González Amezcua O , Hernández Contreras M 
Published: October 2022

Abstract
The structure and self-diffusion properties of confined ions in layered dielectric media were studied with liquid theory and stochastic Langevin equation approaches. The confinement has an enormous impact on the thermodynamic properties of charged molecules and ions in an aqueous solution. The analysis of results demonstrated that reducing the dielectric constant drives the condensation of ions onto the confining surfaces. This effect is accompanied by a concomitant restraining of the diffusion of those mobile ions closer to the boundary surfaces of the pore. We show how these results are linked to understanding the ion equilibrium properties at charged surfaces.
Methodology for the structural design of a type H hidraulic press
Authors: Álvarez M G D , Rosas Q P , Beltrán C F , Damián N Z , Pérez M R 
Published: October 2022

Abstract
The present work shows the methodology for the structural design of a type H hydraulic press. The structural design consists of three parts: the beams, the columns and the fasteners. The methodology evaluates the performance of the beams under the bending stress, then it evaluates that the columns do not exceed the critical load when applying the maximum load and finally, it is evaluated that there is no failure due to shear stress in the bolts. All the aspects evaluated by the methodology were carried out with a design load equal to twice the operating load and later, the design values were positioned at nominal values to proceed with the manufacturing.
A non-homogenous model for the spring-block cellular automaton for earthquakes
Authors: Salinas Martínez A , Pérez Oregon J , Muñoz Diosdado A , Angulo Brown F 
Published: October 2022

Abstract
Many complex systems exhibit self-organizing criticality (SOC). In fact, there is a consensus that the Earth’s crust is a SOC system. The Olami, Feder and Christensen (OFC) spring-block model is a non-conservative SOC model that is used successfully to simulate the dynamics of seismic faults. In this model the system of coupled differential equations representing the spring-block model is mapped to a cellular automaton. In this work we include the idea of asperity, which is an important concept in real seismicity, by varying the distribution in the spring-block network. Considering that in real life seismicity faults are composed of different elements, it is necessary to have a model with these characteristics. We were able of reproduce the Gutenberg-Richter behavior (previously obtained in the classic OFC model) in this non-homogenous distribution.
Thermoluminescent response of LaAlO3:Pr3+ under X-ray beams effect
Authors: Vazquez-Flores N , Vázquez-Cerón E R , Osorio-Valero M , Nolasco-Altamirano D , Barrera-Angeles A A , Rivera-Montalvo T 
Published: October 2022

Abstract
Thermoluminescent (TL) dosimeters are the most used, since they can store information, due to exposure to radiation. Rare earth doped lanthanum aluminate (LaAlO3) ceramic has attracted great attention in recent years for many applications because it shows excellent properties such as thermal stability, color light emission as well as high thermoluminescent intensity. In the present work, TL glow curve under diagnostic X-ray beam was obtained. According to the literature, procedures in interventional cardiology are Thermoluminescent glow curve was analyzed using a Harshaw 3500 TL reader coupled to a personal computer for storage information and future analysis. For irradiation processes was used a diagnostic X-ray source Siemens 256-slice computed tomography (CT) Somaton drive model. TL response of trivalent praseodymium doped lanthanum aluminate as a function of dopant concentration was increasing as concentrations of Pr3+ ion in LaAlO3 was increased. The increase in TL glow peak sensitivity was increased up to 2 % concentration of Pr3+ ion. This TL glow curve exhibited a broad peak centered at 190°C and little shoulder which is consider as the second peak centered at 260°C respectively. The nature of the glow curve form in samples is attributed to at least one type of the trap with relates at least one type of the defect. After experimental results LaAlO3:Pr3+ can be used as thermoluminescent material for diagnostic X-ray beams measurements.
Structural and magnetic properties comparison between cobalt ferrite films obtained by different deposit method
Authors: López-Moreno E , Alvarez G , Montiel H 
Published: October 2022

Abstract
We presented a comparison of the structural, morphological, and magnetic properties between films of cobalt ferrite oxide (CFO), these were deposited with pulsed laser deposition (PLD) and spin-coating (SC) technique. In CFO films obtained by PLD method, a preferential orientation is clearly observed in (004) planes, with a large grain size distribution associated with the splashing effect. For the CFO films obtained by SC method have a homogeneous microstructural distribution with grain size around 50 nm. Additionally, Raman spectra deconvolution was used to estimate the cation distribution in CFO films. Magnetic measurement of CFO films obtained by SC shows a coercive field increment, and which that can be due to a reinforcement in magnetocrystalline anisotropy due to the homogeneous microstructure, whereas for CFO films obtained by PLD, it shows a coercive field decrement due to the splashing effect.
Coupled oscillators with variable mass
Authors: Pineda I , Del Valle G , Hernández G , Muciño D 
Published: October 2022

Abstract
In this work the problem of two containers with variable mass coupled and aligned by springs is studied. The containers are filled with granular mass that lose at a constant rate. Once the containers have been emptied, the classic problem of coupled oscillators with constant mass is recovered. Analytical solutions are obtained even in the damped case where it is observed that the effect of the variable mass combines with the damping factor to produce a decay in the oscillation amplitudes. Finally, also forced coupled oscillators with variable mass problem is considered.
Experimental characterization of a small wind turbine with variable blades angle
Authors: Aragón-González G , León-Galicia A , Calixto-Pérez R , Barragán-Santiago I , Arzate-Pérez M 
Published: October 2022

Abstract
Small wind turbines with fixed blades present a significant disadvantage when operating at low wind speeds. Wind speed increase proportionally with the height to the ground and such wind turbines are installed at most on rooftops, so they face low wind speeds < 10 m/s. This work shows the experimental characterization of a wind turbine prototype with three flat blades and variable orientation angle, to measure the least wind velocity that drives the turbine from the rest. Experimental tests were carried out in a wind tunnel defining two essential points of interest: first, the angle at which it is possible to start the movement of the turbine with the minimum energy; second, the angle that captures the most power from the wind, based on a constant energy input (wind velocity constant).
Multifractal features of the seismicity in Tehuantepec Isthmus, southern México
Authors: Ramírez Rojas A , Flores Márquez E L 
Published: October 2022

Abstract
On September 07, 2017 occurred an earthquake of M8.2 whose epicenter was located at Tehuantepec Isthmus, México. According with the seismicity monitored, spatial and temporal changes were observed after the earthquake in comparison with the historical seismic activity in the zone. Concerning with the temporal changes, the rate of earthquakes occurrence increased and, regarding with the spatial distribution, the epicenters displayed a clear clusterization located between the so-named Tehuantepec Transform/Ridge and the Middle America Trench off Chiapas which is recognized as a tectonic collision region. Based on the observed dynamical behavior of the seismic activity in the Tehuantepec Isthmus subduction zone, in this paper we analyze the magnitude catalogue from 2010 to 2020. The aim is to characterize by applying the multifractal detrended fluctuation analysis three periods of activity, the regular seismicity previous to the main shock, the aftershocks and the post aftershock activity. Our findings suggest that each period is characterized by their own multifractality.
On the theoretical study of the structure of a starch-based biopolymer
Authors: Díaz Pedro J , Olvera Óscar , Cid Alicia 
Published: October 2022

AbstractBiodegradable materials have lower production costs, they are easy to work with, and they are environmentally friendly too. Bioplastics can use natural organic wastes, such as nopal, sargassum, banana peel, corn, algae and a variety of natural products. There is also the synthesis and characterization of these new bioplastics, however, very little is known of their electronic structure of these materials. This study analyzes the interaction of starch, as the fundamental basis of the biopolymer, with glycerol used as a plasticizer and with polyvinyl alcohol to obtain a biopolymer, using the Density Functional Theory (DFT). The possible reaction mechanisms between starch (25% amylose and 75% amylopectin) with glycerol and polyvinyl alcohol are analyzed. The PBE/Def2-TZVP theory level is capable of reproducing the helical structures of amylose and amylopectin.
An electromagnetic pulse over a torus, a particularization of Snell´s law
Authors: Velázquez-Arcos J. M. , Granados-Samaniego J. , Cid-Reborido A. , Alcántara-Montes S. , Pérez-Ricardez A. , Vargas C. A. 
Published: October 2022

Abstract
We apply a new tool that is the Maxwell-Fredholm equations, to study the collision of an electromagnetic pulse with a flat surface of separation between the two parts of a torus-shaped artefact with a highly anisotropic refractive index that forces it to move over its surface. We find that it is possible to establish a relationship between the different angles involved depending on the parameters of the toroidal coordinates, which we call a particularization of Snell’s law.