bluuebunny/crossref_metadata_2025 huggingface dataset:
Tunable toroidal resonance based on hybrid graphene-metal metasurfaces
Authors: Chen Ting , Xiang Tianyu , Wang Jianwei , Xu Mingxing , Lei Tao
Published: October 2022

With the rise of artificial magnetism and metamaterials, toroidal resonance has gained much attention for its special properties. In this paper, we propose a novel hybrid graphene-metal metamolecule consisting of a square bracket-like resonator and two asymmetric U-shaped resonators. By applying various Fermi energies to graphene, the amplitude of electromagnetically induced transparency (EIT) can be efficiently manipulated, and the maximum amplitude modulation depth can attain 81% in the microwave region. Numerical simulations and theoretical analysis demonstrate that the dynamic manipulation is mainly induced by the active tuning toroidal resonance through the recombination effect of the conductive graphene. Also, the maximum group delay of 85 ps can be attained and controlled with the increasing Fermi energy. The proposed hybrid graphene-metal metamolecule and dynamically manipulating mode presents a novel modulating strategy of EIT-like analog based on the toroidal response, which has great application for the design of efficient tunable resonators, filters, and sensors.
The impact of semiconductor surface states on vacuum field emission
Authors: Kim Taeyoung , Joishi Chandan , Shih Pao-Chuan , Palacios Tomás , Rajan Siddharth
Published: October 2022

This work presents a theoretical analysis of the impact of surface states on vacuum field emission currents in semiconductors. In wide and ultra-wide bandgap semiconductors such as GaN and AlGaN, low electron affinity has been proposed as a benefit for field emission into vacuum. However, in these materials, the surface Fermi level at the surface is pinned well below the conduction band, and the surface depletion barriers due to the surface Fermi level pinning can be comparable to or higher than the electron affinity. Therefore, analysis of field emission requires consideration of not only the vacuum potential barrier set by electron affinity, but also the depletion region near the semiconductor surface. In this paper, we develop analytical models to predict field emission currents with careful consideration of the impact of surface states on the energy band alignment. The results are used to provide guidelines for design of field emitters that could benefit from the low electron affinity of semiconductors such as Al(Ga)N.
Giga-hertz ultrasonic reflectometry for fingerprint imaging using epitaxial PbTiO3 transducers
Authors: Nakamura Kae , Koike Yuna , Sato Yusuke , Yanagitani Takahiko
Published: October 2022

A fingerprint reader based on epitaxial PbTiO3 (PTO) transducer array operating thickness extensional mode in GHz range was fabricated. The device consisted of nine square transducers with 0.1 mm per side arranged 1.3 mm apart in a 3 × 3 array. Minimum conversion loss of the fabricated transducer was 2.5 dB at 0.8 GHz, and electromechanical coupling coefficient kt2 was estimated to be 28.9%. In contrast to MHz range ultrasonic fingerprint readers such as those based on piezoelectric micromachined ultrasonic transducers using a piezoelectric transducer and ScAlN, a GHz range transducer enables imaging in higher spatial resolution. Furthermore, PTO transducers have a high dielectric constant and electromechanical coupling coefficient kt2. A high dielectric constant realizes 50 Ω impedance matching with small electrode area. The small acoustic source is expected to improve the spatial resolution of a fingerprint reader. We achieved the fingerprint imaging by evaluating the acoustic reflectance of the medium/transducer interface. Furthermore, piezostage that allows mechanical movement in the 100 nm order was introduced to image a 12 × 12 μm2 area with total of 3600 data points.
The transition from thermionic to space charge limited emission for needle-like surfaces—A particle-in-cell simulation study
Authors: Singh Gaurav , Biswas Debabrata , Kumar Raghwendra
Published: October 2022

We perform particle-in-cell simulations of thermionic emission from hemi-ellipsoidal shaped needle emitters. The Schottky corrected Richardson–Dushman equation is used to compute the emitted current from the curved emitter surface. It is shown that the transmitted thermionic current increases with cathode temperature before eventually settling to the enhanced space charge limited (SCL) current. It is further shown that the critical temperature at which transition to the saturation region occurs increases with the height of the emitter, leading to a softening in the transition. This may be attributed to the non-uniformity in the cathode work function as in planar diodes. The SCL current is found to increase linearly with the electrostatic apex field enhancement factor as predicted recently [Singh et al., Phys. Plasmas 27, 104501 (2020)].
Revealing the simultaneous increase in transient transmission and reflectivity in InN
Authors: Jia Junjun , Yagi Takashi , Mizutani Mari , Yamada Naoomi , Makimoto Toshiki
Published: October 2022

The ultrafast transient behavior of InN under intensive laser irradiation remains unclear. The simultaneous measurements of pump–probe transient transmission and reflectivity are reported in this study. The irradiation-induced change in the dielectric constant of InN films due to the generation of thermalized carriers gives rise to complex transient behavior, and simultaneous increase in both transient transmission and reflectivity are observed at certain wavelengths. Herein, transient transmission is interpreted as the occupation probability of thermalized electrons at the probing level originating from a hot Fermi–Dirac distribution, and our calculation results are in good agreement with the experiments. Likewise, the Drude-like response due to the collective motion of thermalized carriers causes the increase in transient reflectivity, which depends on the change of dielectric constant caused by the collective motion of thermalized carriers. The ultrafast carrier dynamics is modeled by calculating the temporal evolution of the occupation probability of thermalized electrons in the conduction band. On the basis of the two-temperature model, the electron–phonon scattering time is extrapolated to be ∼300 fs in InN, which dominates the cooling of excited electrons.
Ballistic guided electrons against disorder in graphene nanoribbons
Authors: Robles-Raygoza E. J. , Ibarra-Sierra V. G. , Sandoval-Santana J. C. , Carrillo-Bastos R.
Published: October 2022

Graphene nanoribbons (GNRs) are natural waveguides for electrons in graphene. Nevertheless, unlike micrometer-sized samples, conductance is nearly suppressed in these narrow graphene stripes, mainly due to scattering with edge disorder generated during synthesis or cut. A possible way to circumvent this effect is to define an internal waveguide that isolates specific modes from the edge disorder and allows ballistic conductance. There are several proposals for defining waveguides in graphene; in this manuscript, we consider strain folds and scalar potentials and numerically evaluate these proposals’ performance against edge and bulk disorder. Using the Green’s function approach, we calculate conductance and the local density of states of zigzag GNRs and characterize the performance of these different physical waveguiding effects in both types of disorders. We found a general improvement in the electronic conductance of GNR due to the presence of the internal waveguiding, with the emergence of plateaus with quasi-ballistic properties and robustness against edge disorder. These findings are ready to be applied in modern nanotechnology and are being experimentally tested.
Enhanced performance on piezoelectric MEMS vibration energy harvester by dynamic magnifier under impulsive force
Authors: Aphayvong Sengsavang , Murakami Shuichi , Kanda Kensuke , Fujimura Norifumi , Yoshimura Takeshi
Published: October 2022

Vibration energy harvesters that use resonance phenomena exhibit a high output power density for constant frequency vibrations, but they suffer from a significant drop in performance for non-steady-state vibrations, which are important for practical applications. In this work, we demonstrate that the output power under an impulsive force can be increased significantly by placing a U-shaped metal component, called a dynamic magnifier (DM), under an MEMS piezoelectric vibration energy harvester (MEMS-pVEH) with a 6 mm long cantilever using a 3 μm thick Pb(Zr,Ti)O3 film. Based on the results of numerical calculations using a model of pVEH with a two-degree-of-freedom (2DOF) system, the DM was designed to have the same resonant frequency as the MEMS-pVEH and a high mechanical quality factor (Qm). The waveforms of the output voltage of the fabricated 2DOF-pVEHs were measured for impulsive forces with various duration times, and the output power was calculated by integrating the waveforms over time. The output power of the MEMS-pVEH placed on the DM with a Qm of 56 showed a gradual change according to the duration of applying an impulsive force and a maximum of 19 nJ/G2 (G: gravitational acceleration) when the duration of the impulsive force was 3.8 ms. This result was about 90 times greater than the output power of the MEMS-pVEH without a DM. While it is not easy to fabricate pVEHs with a complex 2DOF structure using only the MEMS process, we have demonstrated that the output power can be significantly improved by adding a spring structure to a simple MEMS-pVEH.
∼8.5 μm-emitting InP-based quantum cascade lasers grown on GaAs by metal-organic chemical vapor deposition
Authors: Xu S. , Zhang S. , Kirch J. D. , Suri S. , Pokharel N. , Gao H. , Kim H. , Dhingra P. , Lee M. L. , Botez D. , Mawst L. J.
Published: October 2022

Room-temperature, pulsed-operation lasing of 8.5 μm-emitting InP-based quantum cascade lasers (QCLs), with low threshold-current density and watt-level output power, is demonstrated from structures grown on (001) GaAs substrates by metal-organic chemical vapor deposition. Prior to growing the laser structure, which contains a 35-stage In0.53Ga0.47As/In0.52Al0.48As lattice-matched active-core region, a ∼2 μm-thick nearly fully relaxed InP buffer with strained 1.6 nm-thick InAs quantum-dot-like dislocation-filter layers was grown. A smooth terminal buffer-layer surface, with roughness as low as 0.4 nm on a 10 × 10 μm2 scale, was obtained, while the estimated threading-dislocation density was in the mid-range × 108 cm−2. A series of measurements, on lasers grown on InP metamorphic buffer layers (MBLs) and on native InP substrates, were performed for understanding the impact of the buffer-layer's surface roughness, residual strain, and threading-dislocation density on unipolar devices such as QCLs. As-cleaved devices, grown on InP MBLs, were fabricated as 25 μm × 3 mm deep-etched ridge guides with lateral current injection. The results are pulsed maximum output power of 1.95 W/facet and a low threshold-current density of 1.86 kA/cm2 at 293 K. These values are comparable to those obtained from devices grown on InP: 2.09 W/facet and 2.42 kA/cm2. This demonstrates the relative insensitivity of the device-performance metrics on high residual threading-dislocation density, and high-performance InP-based QCLs emitting near 8 μm can be achieved on lattice-mismatched substrates.
Onset conditions for Mach disk formation in underexpanded jet flows
Authors: Muraoka Ryota , Hiejima Toshihiko
Published: October 2022

In this study, the formation conditions of the Mach disk in an underexpanded jet flow were numerically and theoretically investigated under sonic injection conditions and the assumption of an axisymmetric flow. The numerical results demonstrated that the threshold nozzle-pressure ratio (NPR) at which the Mach disk occurred was situated between 3.03 and 3.12, which is lower than those reported in the previous studies. Since the oscillation frequency of the Mach disk was approximately constant over a wide range of NPRs and the amplitude was weak, it was regarded as a steady shock. In addition, the Mach disk was found to form when the total pressure loss reached approximately 40%. To predict the appearance of the Mach disk, we proposed a theoretical model based on a quasi-one-dimensional flow by considering the Mach disk as a normal shock wave on the axis. Based only on injection and ambient conditions, the total-pressure loss ratio derived from the model was in good agreement with that obtained from the numerical simulations, indicating that the proposed model provides useful knowledge for Mach disk occurrence prediction.
A non-intrusive reduced order model with transformer neural network and its application
Authors: Wu Pin , Qiu Feng , Feng Weibing , Fang Fangxing , Pain Christopher
Published: October 2022

In this paper, a novel method to construct non-intrusive reduced order model (ROM) is proposed. The method is based on proper orthogonal decomposition and transformer neural network. Proper orthogonal decomposition is used to generate the basis functions of the low-dimensional flow field, and the coefficients are taken as low-dimensional flow field features. Transformer network is used to extract temporal feature relationships from low-dimensional features. Compared with recurrent neural network and convolutional neural network, transformer network can better capture flow dynamics. At online stage, the input temporal flow sequences are calculated in parallel and can effectively reduce online calculation time. The model proposed in this paper has been verified in two scenarios: two-dimensional flow past a cylinder and two-dimensional flow past a building group. Experimental results show that our model can better capture the flowing change details and has higher accuracy. Compared with the ROM based on long short-term memory and temporal convolutional network, the prediction error is reduced by 35% and 60%, and the time cost is reduced by 65% and 60%. Finally, we apply the ROMs to a practical three-dimensional complicated scenario, flow past London South Bank University, and discuss future development of ROMs.
Evidence of direct charge transfer in plasmon-mediated photocatalytic water splitting: A time-dependent density functional theory study
Authors: Feng Qingying , Zhang Ying , Feng Hao , Liu Dong , Li Qiang
Published: October 2022

Photocatalytic water splitting is a promising route for hydrogen production and solar energy storage. Plasmon-mediated water splitting has the potential to harvest photons with longer wavelengths compared with semiconductor-based photocatalysis. However, the mechanism of plasmon-induced charge transfer, the determining step of photochemistry, is not well understood. Here, we studied plasmon-mediated water splitting at atomic length scale and femtosecond timescale. Linear-response time-dependent density functional theory calculations and Ehrenfest dynamics simulations were performed for a realistic H2O@Au6 model excited by the femtosecond laser. Wavelength-dependent charge transfer mechanisms were demonstrated. Especially, for the excitation of 2.25 eV that falls into the visible spectrum, evidence was presented for the dominant direct transfer of d-orbital electrons from the gold cluster to the adsorbed water molecule. In this mechanism, the charge transfer leapfrogs the processes of excitation and thermalization within gold described in the classical theory. The results can assist the design of more energy-efficient solar water splitting.
A novel algorithm for visualizing and quantifying vortices in complex 3D flows based on marching and converging vortex atoms
Authors: Wang Chengyue , Shen Yunian , Mang Shanshan , Gao Qi , Wang Zhongyi , Wang Jinjun
Published: October 2022

Numerous investigations aiming to reveal the underlying physics behind complex flows highlighted the important roles of vortices. This article proposes an integrative algorithm for visualizing and quantifying the vortices in three-dimensional flows. The algorithm not only extracts the vortex centerlines but also returns the vortex radii and circulations varying along the centerlines. The novel aspect of this algorithm is to represent the vortex field as a collection of discrete vortex atoms. By iteratively updating the positions of these vortex atoms, the algorithm manipulates them into marching toward the underlying vortex centerlines. The radii and circulations varying along the centerlines are estimated based on the vortex atoms converged on the vortex centerlines. The accuracy and robustness of the algorithm are first accessed by numerical tests based on a synthetic vortex ring. Subsequently, the algorithm is employed to investigate the complex vortices in a turbulent boundary layer, validating the scaling law of the vortices reported in the literature. At last, the algorithm is applied to the three-dimensional experimental data of the wake flow behind a wall-mounted hemisphere. It concludes that the algorithm can be used as an effective tool for analyzing vortices in complex flows.
Thermodiffusion of polymer solutions and colloidal dispersions in mixed solvents
Authors: Sommermann D. , Schraml M. , Köhler W.
Published: October 2022

Two-color optical measurements of thermodiffusion in ternary mixtures frequently suffer from ill-conditioned contrast factor matrices, whose inversion leads to very large experimental errors. In this contribution, we show how the error amplification can be avoided in situations where a priori knowledge about the directions of the eigenvectors of the diffusion matrix is available. We present optical beam deflection experiments on solutions of the polymer polystyrene of Mw = 4880 g/mol in a mixed solvent of toluene and cyclohexane. In this system, the two diffusion eigenvalues differ by almost one order of magnitude. The large eigenvalue can be attributed to the interdiffusion of the two solvents and the small one to the polymer diffusion relative to the mixed solvent. The pre-selection of the eigenvectors renders the method stable against fluctuations of the experimental parameters. Both the diffusion and the Soret coefficients attributed to the two modes agree very well with the respective values of corresponding binary mixtures.
Corrigendum to: An integrative taxonomic study of the genus Theromyzon (Hirudinea: Glossiphoniidae), with description of a new North American species
Authors: Foote Maddy , Iwama Rafael , de Carle Danielle , Kvist Sebastian
Published: October 2022

Theromyzon Philippi, 1867 is a genus of sanguivorous, freshwater leeches in the family Glossiphoniidae. The genus is broadly distributed across the globe, possibly due to the frequent feeding in the nasopharyngeal cavities of migratory waterfowl that may allow for long distance dispersal. The genus has a history of taxonomic confusion resulting from mischaracterisations of key morphological features of type specimens that have produced several re-descriptions and synonyms. Here, we bring partial order to this confusion through robust morphological investigations of newly collected North American (and a single South American) specimens, representing most of the known species diversity from this continent. We also produce the first species-level phylogeny for Theromyzon and attempt to understand species boundaries regarding both morphology and genetics. Our results demonstrate that there are at least five species of Theromyzon present in North America (T. bifarium, T. tessulatum, T. rude, T. trizonare, and a clade that needs further investigation), and a hitherto undescribed taxon that does not conform to any previously published description, and represents a unique lineage in the phylogeny; we describe this new species under the name Theromyzon tigris sp. nov. This study sheds light on the discriminatory power of select morphological characters and the distribution of phenotypes within the genus. We also provide a comprehensive classification framework for the known species within the genus designed to facilitate identification and minimise future taxonomic confusion.
Using literature and expert knowledge to determine changes in the bird community over a century in a Turkish wetland
Authors: Arslan Dilara , Ernoul Lisa , Béchet Arnaud , Döndüren Ömer , Sıkı Mehmet , Galewski Thomas
Published: October 2022

Context Bird species have been studied and documented abundantly in the past decades and are good indicators of ecosystem conditions, providing useful information of the changes in the ecological state of wetlands over time. However, monitoring data for birds in wetland sites are often disparate and not homogeneous over time and among species, which complicates the interpretation of trends. Aims We examined historical literature from 1835 to 2019, complemented by an expert knowledge survey and citizen-science databases to estimate the abundance of species, and evaluated changes in the structure and composition by average bird abundances. Key results Our results suggested that land-cover and land-use changes have shaped the local bird community, with a decline in agricultural and grassland bird species as a result of changes in agricultural practices. Coastal wetland and marine birds have increased in abundance, most probably linked to the extension of saltpans and successful conservation measures. Conclusions These trends in bird communities demonstrate the impacts of different land management strategies on biodiversity. Implications This methodology can be replicated in other Ramsar and wetland sites around the world to raise new conservation issues and improve site conservation.
A comparison of lead-based and lead-free bullets for shooting sambar deer (Cervus unicolor) in Australia
Authors: Hampton Jordan O. , Bengsen Andrew J. , Flesch Jason S. , Toop Simon D. , Davies Christopher , Forsyth David M. , Kanstrup Niels , Stokke Sigbjørn , Arnemo Jon M.
Published: October 2022

Context In response to the toxic health threats posed by lead (Pb), there is currently a focus on transitioning to lead-free bullets for shooting wild animals. Aim We aimed to quantify the killing efficiency and animal welfare outcomes of lead-based and lead-free (copper-based) bullets for ground-based shooting of sambar deer (Cervus unicolor) in Victoria, south-eastern Australia. Methods We used shooter-collected data from recreational diurnal hunting and professional nocturnal culling during 2020–2021. Shooters recorded rifle calibre, cartridge type, bullet mass, bullet type, shooting outcomes (miss, wound or kill), shooting distance, flight distance (the distance between where the animal was shot and where it died) as an assumed positive correlate of time to incapacitation, anatomical zones struck by bullets, and frequency of bullet exit wounds. We used flight distance as our response variable, assuming that it is positively correlated with time to incapacitation. To examine the role of several predictor variables (including bullet type) potentially influencing flight distance, the dataset was reduced to those deer killed with a single thoracic shot. Key results Our data captured shooting events involving 276 deer, with 124 deer shot at with lead-based bullets and 152 with copper-based bullets. Most (87%) of the deer were killed with a single shot. The frequency of non-fatal wounding was <4% for both bullet types and there was no distinct difference in the probability of a single shot kill for deer shot with either bullet type. For those deer killed with a single thoracic shot (n = 198), there was no evidence that bullet energy or shooting distance influenced flight distance. After accounting for differences in terminal kinetic energy, the mean flight distance of deer shot with lead-free bullets (35 m) was 56% greater than that of deer shot with lead-based bullets (22 m). Conclusions Lead-based and lead-free bullets produced similar animal welfare outcomes for shooting sambar deer. Implications A transition to lead-free ammunition for shooting sambar deer would have minimal impact on efficiency or animal welfare outcomes.
A Cantú syndrome mutation produces dual effects on KATP channels by disrupting ankyrin B regulation
Authors: Crespo-García Teresa , Rubio-Alarcón Marcos , Cámara-Checa Anabel , Dago María , Rapún Josu , Nieto-Marín Paloma , Marín María , Cebrián Jorge , Tamargo Juan , Delpón Eva , Caballero Ricardo
Published: October 2022

ATP-sensitive potassium (KATP) channels composed of Kir6.x and sulfonylurea receptor (SURs) subunits couple cellular metabolism to electrical activity. Cantú syndrome (CS) is a rare disease caused by mutations in the genes encoding Kir6.1 (KCNJ8) and SUR2A (ABCC9) that produce KATP channel hyperactivity due to a reduced channel block by physiological ATP concentrations. We functionally characterized the p.S1054Y SUR2A mutation identified in two CS carriers, who exhibited a mild phenotype although the mutation was predicted as highly pathogenic. We recorded macroscopic and single-channel currents in CHO and HEK-293 cells and measured the membrane expression of the channel subunits by biotinylation assays in HEK-293 cells. The mutation increased basal whole-cell current density and at the single-channel level, it augmented opening frequency, slope conductance, and open probability (Po), and promoted the appearance of multiple conductance levels. p.S1054Y also reduced Kir6.2 and SUR2A expression specifically at the membrane. Overexpression of ankyrin B (AnkB) prevented these gain- and loss-of-function effects, as well as the p.S1054Y-induced reduction of ATP inhibition of currents measured in inside-out macropatches. Yeast two-hybrid assays suggested that SUR2A WT and AnkB interact, while p.S1054Y interaction with AnkB is decreased. The p.E322K Kir6.2 mutation, which prevents AnkB binding to Kir6.2, produced similar biophysical alterations than p.S1054Y. Our results are the first demonstration of a CS mutation whose functional consequences involve the disruption of AnkB effects on KATP channels providing a novel mechanism by which CS mutations can reduce ATP block. Furthermore, they may help explain the mild phenotype associated with this mutation.
XI International Congress on Physics Engineering
Authors: Granados Samaniego J , Tavera Romero F , Hernández López R T , López Gonsález G
Published: October 2022

Lis of Introduction, Justification, Results, Remote communication, Organizing committee, Acknowledgments are available in this pdf.
Adsorption of formaldehyde on F@graphene layer
Authors: Arellano J S
Published: October 2022

This work study the interaction of a toxic substance, formaldehyde, with a F@graphene layer. Using density functional theory, three cases of adsorption of formaldehyde, CH2O, on a finite sheet of graphene with 32 carbon atoms are shown. In the first two cases, the formaldehyde is adsorbed on the graphene sheet. The third case shows that under certain conditions it is possible to dissociate the formaldehyde molecule in the HF dimer and the formyl molecule, CHO. Although there are studies that report the toxicity of formaldehyde, it remains to be seen whether the toxicity of the CHO fragment in the reaction, F + CH2O → HF + CHO, may or may not be less than that of formaldehyde.
Study of the effect of dynamic viscosity on the performance of a portable microinjector for severe dry eye treatment using a glycerol-water mixture as a test fluid.
Authors: Babakidi Narcisse Meni , Gamboa Gonzalo Viramontes , Ibarra Bracamontes Laura Alicia , Reyes Israel Luna
Published: October 2022

This article presents the experimental results of a series of performance tests performed on a microinjector designed to deliver different artificial tear solutions to patients with severe dry eye syndrome. The device is intended to aid in the treatment of this syndrome by providing a continuous injection of artificial tears as needed that overcomes many of the deficiencies inherent in dripping from the manual method. In this work, a set of experiments were carried out to quantify the temporal error that allow determining the dynamic behavior of the viscosity of the glycerol/water mixture as a suitable test solution for the device and then comparing it with the use of commercial artificial tears to define an acceptable viscosity range with a lower temporal error for the correct operation of the system. The experimental method of viscosity measurement was used by means of an Ostwald viscometer that allows determining the times that flow the volume of various percentages by volume of glycerol/water and drops. In addition, the gravimetric density method was used to determine the density and subsequently by the Poiseuille relationship with respect to the densities of percentages in volume of glycerol/water and drops, the different times that flow through a capillary tube, the dynamic viscosity. The results obtained during the operation of the tested microinjector suggest that the microinjector can function correctly without problem in a range of evaluated dynamic viscosity of 1 to 1500 mP a.s with a maximum temporal error of ∼ 5 %. The temporal error evaluated is a parameter that is necessary to know for the well-being of patients using this device and the viscosities of the products used do not significantly influence the performance of the microinjector.
Laser fragmentation of metal powders suspended in water for hydrogen generation
Authors: Escobar Alarcón L , Iturbe García J L , Solis Casados D A , Romero S , Haro Poniatowski E
Published: October 2022

The hydrogen production by laser induced fragmentation of metal powders suspended in water is investigated. Powders of metals such as Al, Mg and three Al-Mg alloys were suspended in distillated water and subjected to laser irradiation to promote a displacement chemical reaction of hydrogen from water. All the studied powders under laser irradiation produced H2 and the volume rise as a function of the laser fluence, amount of powder and irradiation time following linear behavior. This on-demand production of hydrogen could be an option to release the hydrogen contained in water (H2O) in situ. Using this configuration, a maximum hydrogen generation rate close to 1.7 mL/min is obtained.
Manufacture of porous carbon thin films for energy storage
Authors: Cabrera Rodríguez O , Trejo Valdez M D , Villar Masetto T I , Torres San Miguel C R
Published: October 2022

In the present work, a technique to generate pores in Vulcan VCX-72 and VCX-72R commercial coal through the Hummers method and the elaboration of membranes is shown. The product obtained through the process was cleaned and dried, then SEM microscopy in which the generation of pores in the coal was observed. Membranes were elaborated using the material and were placed in an electrochemical cell in a set up of three electrodes immersed in an acid solution of H2SO4. Autolab® potentiostat and the Nova® software were used to carry out electrochemical tests that showed capacitive properties in the Hummers method’s coal.
Design of a compliant mechanism for a sternum prosthesis using the pseudo-rigid-body model
Authors: Ramirez O , Hernández Cerero R , Prieto Vazquez A Y , Torres San Miguel C R
Published: October 2022

When a sternum prosthesis is implemented, it must allow the movement of the rib cage. The sternum prosthesis designs that have been developed are completely rigid, this aspect can present discomfort when breathing, as well as fixation problems between the prosthesis and the bone tissue. The aim of this work is to develop a flexible device that allows the movement of the rib cage during breathing. Compliant mechanism design was developed by using the pseudo-rigid body model (PRBM) starting from a 4-bar rigid mechanism. The flexible model was obtained by developing the methodology of replacement from rigid to flexible body. The results show the obtained parameters of the compliant mechanism and the three-dimensional model for subsequent numerical and experimental analysis.
Analysis of the stresses obtained in adobe walls without reinforcement against lateral loads obtained through modeling in SAP 2000
Authors: Ospina Henao P A , Oñate Ballesteros R D , Peñaranda Vega J S
Published: October 2022

When talking about the techniques of collection, elaboration and construction of adobe and in general of constructions with earth, there is always a great variety of construction techniques, and composition in the blocks that vary according to the region and culture [1], which generates a great uncertainty, and causes that, at present, although we have decree 2113 of 2019, we do not have clarity as to a method and characteristics universally valid and accepted in our country. It is for this reason that in this work we show the modelling of a series of type walls by means of the SAP 2000 program for which applying a static linear analysis for finite elements and an analysis of stresses the service limit states given for a series of walls of different composition are determined, which showed that the percentage of failure for adobe walls is 40% under the given methodology, under this threshold it was determined that the element can be in service and have functionality, exceeding this value it is denoted that the element will lose its functionality without entering into risk of collapse until reaching a percentage of 50%. Finally, the models are obtained with the appropriate effort analyses and design recommendations under the criteria of the results obtained, leaving the possibility of performing an experimental phase to develop the analogy with those raised in the models.
Pre-heating of an aluminum sample using a continuous laser diode in LIBS experiments
Authors: García Villarreal A , Robledo Martinez A , Sobral H
Published: October 2022

We present here the study of the pre-heating of an aluminum sample in laser-induced plasma spectroscopy (LIBS) experiments. The pre-heating of the sample was made using a continuous-wave (CW) laser diode having a wavelength of 450nm and 3.8 W power. The laser diode is focused on the aluminum sample by means of a plane-convex lens with a focal length of 10 cm. The ablation plasma is created by a pulsed Nd:YAG laser with 7ns of pulse duration. The results of using different energy values per pulse of the ablation laser on the pre-heated sample are reported. The pre-heating of the aluminum sample, using this laser diode, shows an increment of 30-50% in the ionic line intensity.
Experimental assessment of cruciate ligaments performance on a Lower Limb Impactor (LLI)
Authors: López Álvarez I , Figueroa Flores G , Rivera Hernández M A , Torres SanMiguel C R
Published: October 2022

The Lower Leg Impactor (LLI) has been used since 2005 without any modification. However, this model lacks similitude with the human knee. This work analyzes the operation of a four-bar mechanism applied in LLI, as a movable element of the knee. In addition, Runover experimental tests were carried out using the LLI made with ultra-high molecular weight polyethylene (UHMWPE), to analyze the accuracy of movable knee implemented in the LLI under the European Enhanced Vehicle-Safety Committee/Working Group 17 (EEVC/WG17) standard. The results show the possible injuries suffered in the double four-bar mechanism and the different injuries developed in pedestrians.
Evaluation of the martensitic transformation in a rapidly solidified Co – Cr alloy subjected to thermomechanical processing by XRD technique
Authors: Luna-Manuel J C , Ramirez-Ledesma A L , Juarez-Islas J A
Published: October 2022

The martensitic transformation in Co-Cr based alloys is complex and is intimately influenced by the processing, for this reason, is still investigated. X-ray diffraction technique was used to identified and quantified the phases present in a rapidly solidified Co – 20 wt. % Cr alloy in three different conditions: as-cast (AC), hot – rolled (HR), and hot – rolled plus annealing (HR + A). After HR, the diffraction pattern exhibits a peak partitioning located at a diffraction angle (2θ) of 44.7°, where the (111) plane of the face centered cubic phase (γ – CoFCC) and the (0002) plane of the hexagonal compact phase (ε – CoHCP) coexist. Additionally, for all conditions, the lattice parameters in the present phases, γ – CoFCC and ε – CoHCP, were determined using Bragg’s law. The lattice contraction in the S(111) plane was determined, and the density of the (111) plane was calculated. The stacking fault energy, (γSFE), for all conditions was calculated using the Olson-Cohen method. The hexagonal compact phase volume percentage was obtained with the Sage and Guillaud equation and for all conditions was above 90 %.
Calculation of the fuel consumption, fuel economy and carbon dioxide emissions of a heavy-duty vehicle
Authors: Pantoja Gallegos J L , Dominguez Vergara N , Dominguez Perez D N
Published: October 2022

The calculation of the fuel consumption, fuel economy and carbon dioxide emissions (CO
2) of a heavy-duty vehicle is detailed. First the forces over a vehicle in motion are calculated and then the necessary torque and the revolutions per minute (rpm) of the engine to provide the tractive force are found. The fuel consumption in kilograms per second for a pair of rpm and torque is obtained from the engine fuel map. The CO
2 emissions are obtained from the fuel consumption. The maxima of the torque and power of a 455 horse power engine are presented as a function of the rpm as well as the specific fuel consumption of the vehicle at the maxima values of the torque. Finally, the fuel economy of the vehicle moving in part of one of the cycles used by the Environmental Protection Agency of the United States of America to certify heavy-duty vehicles to fuel consumption and CO
2 emissions is calculated.
Surface Morphology and Structure in ZnO films doped with Ga and In impurities
Authors: El Filali Brahim , Torchynska Tetyana , Polupan Georgiy , Lozada Erick Velázquez , Ballardo Rodriguez Isis Chetzyl , Ramirez Garcia Jorge Luis
Published: October 2022

The ZnO:Ga:In nanocrystal (NC) films co-doped with Ga and In donor type impurities have been investigated The films were produced by spray pyrolysis ultrasonic on Si substrates kept at 400°C. The group of samples was grown with permanent In content of 1at% in the films, and with various Ga contents of 0.5 at% up to 2.5 at% Ga. All samples for better crystallization have been further annealed in a nitrogen flow (5 L/min) at 400°C during 4h.

The non-monotonous varying the surface morphology has been detected in ZnO:Ga:In NC films. With a small Ga content (≤1.0 at%) and a high Ga content (≥2.0 at%), the grains have the form of small sheets distributed randomly on the surface. The sheet like shape changes to nanorod with hexagonal cross sections of the size 50-100 nm in films with 1.5 at% Ga. With all Ga concentrations the ZnO films studied demonstrated the crystal structures of wurtzite. However, the XRD peak positions and ZnO lattice parameters change non monotonically versus Ga contents. The factors that favor the non-monotonic change of the parameters of the ZnO crystal lattice have been analysed. The Ga/In doping concentrations necessary to obtain ZnO films with low roughness and flat surface morphology have been estimated.
Microwave absorption dynamics in Fe3O4nanopowders around Verwey transition
Authors: Alvarez G , Montiel H.
Published: October 2022

In Fe3O4 nanopowders were carried out microwave absorption measurements at X-band (8.8-9.8 GHz), in the 89-300 K temperature range, by means of the ferromagnetic resonance (FMR), the magnetically modulated microwave absorption spectroscopy (MAMMAS) and the low-field microwave absorption (LFMA). The Verwey transition around Tv
∼ 137 K has been detected employed the FMR parameters: the resonant field (Hres
) and the linewidth (ΔHpp
), as temperature function. MAMMAS response shows features that can also be associated with Verwey transition. Finally, LFMA spectra are associated with a magnetic state in Fe3O4 nanopowders, where a lineal component with positive slope and a hysteresis loop around zero magnetic field are clearly observed, and behavior in temperature of the lineal component also suggests the presence of the Verwey transition.
Correlation operation in the Fresnel domain and truncation operations applied to the simultaneous encryption of two images
Authors: Vilardy Juan M , Alfaro Eder , Jimenez Carlos J
Published: October 2022

A new nonlinear encryption-decryption scheme for two images using: double random phase encoding (DRPE), random phase masks (RPMs), amplitude and phase encoding, correlation operation in Fresnel domain (FrD) and truncation operations (amplitude truncation, AT and phase truncation, PT), is proposed. AT and PT are operations that work on complex-valued functions (images) in a nonlinear way, with the purpose of selecting the information contained in a complex-valued image, respectively. The first step of the encryption scheme is encoding two original images in amplitude and phase. The encryption or decryption scheme utilizes the correlation operation in FrD, AT, PT and two RPMs in a specific way to obtain the encrypted or decrypted images. The use of the AT and PT operations allow a better security of the encryption and decryption schemes because the nonlinearities introduced by these operations and the generation of two new encryption keys. The encrypted image of this proposal is real valued and the correlation operation in FrD introduces two new keys improving the security of the encryption and decryption schemes. The keys of the proposed security schemes are six and the right values of these all keys have to be used in the decryption scheme to recover the two initial images used in the input of the encryption scheme.
Effect of quantum mechanics and relativistic frequency parameter on hot deformation behaviour of CoCrFeMnNiC0.5high entropy Alloy
Authors: Muñoz-Andrade J D
Published: October 2022

In the present investigation, a comparative study is carried out between the effect of the frequency parameter suggested by Zener-Hollomon (Z) and the effect of quantum mechanics and relativistic frequency parameter formulated by Muñoz-Andrade (M) on hot deformation behavior of CoCrFeMnNiC0.5high entropy alloy (HEA), in the temperature range between 973 K and 1273 K and in the strain rate range between 0.001 and 1 s-1. The crucial findings denote that at strain of ε=0.8, the frequency parameter M increased when the temperature and the strain rate increased. Moreover, the nature wavelength (λ) associated with the frequency parameter M is reduced as the temperature and the strain rate are increased. This natural wavelength λ of CoCrFeMnNiC0.5HEA development during the thermomechanical conditions applied in the present study are in the range between 0.346μm and 0.509μm. Such values are in a closed agreement with the width of the microbands (MBs) produced inside of grains. These MBs are considered as the dominant mechanism inside of crystals during the microstructural evolution related with the phenomenology and mechanics of discontinuous dynamic recrystallization in this HEA. These findings associated with the Muñoz-Andrade frequency parameter M, fully coincide with the Big Bang theory. Nevertheless, the findings associated with the Zener-Hollomon parameter Z, do not obey the Big-Bang theory. For example, the frequency parameter Z at the same deformation (ε=0.8) and thermomechanical conditions decreased as the temperature and the strain rate are increased. Additionally, the wavelength λ associated with the frequency parameter Z is in the range between 162μm and 1630μm, where such values does not coincide with the width of the MBs produced inside of grains during hot deformation of this CoCrFeMnNiC0.5HEA.
Simplified mechanical system for knee rehabilitation
Authors: Mendoza Martínez J , Aguilar Pérez L A , Torres San Miguel C R
Published: October 2022

Muscle atrophy refers to the thinning of muscles losing their tone and strength. Knee rehabilitators are usually based on a 4-bar system due to its simplicity, and the passive movement sought the rehabilitation of joints, seeking comfort in the patient. This research determines the critical movements and the correct selection of the 4-bar mechanism, considering the restrictions according to the rules of the flat mechanisms. In addition, a kinematic analysis based on geometric models is carried out for validation through a computer program for its subsequent selection of the actuator to obtain the desired movement according to the initial conditions of the knee rehabilitator that considers the rehabilitation of the patient in a sedentary position. The result shows a mechanism with an isokinetic movement employed for knee rehabilitation.
Oscillation of two physical pendulums held by a rod
Authors: Cid Alicia , Díaz Pedro J. , Zurita Marco A. , Mina Alberto , Granados S Jaime A. , Velázquez Joshua A. , Velázquez A Juan M. , Del valle Luisa G.
Published: October 2022

By calculating the kinetic and potential energies, applying Lagrangian mechanics, with the Euler-Lagrange equations, we obtained the equations that were used to analyze the pendulum motion of a mechanical system consisting of an arrangement of three rigid rods, two of them with equal mass m and length l, which behave like physical pendulums, which are joined by means of a third, a rigid rod of mass M and length L. In the latter, there is a square block of mass M

a
and length L

a
that can be moved freely on the horizontal rod. The block contains a granular medium that is dislodged over time, thus forcing the vertical rods to generate a peculiar vibrational motion. Finally, the system of equations of motion, by numerical methods was solved.
Dynamic study of the pendulum-n and the beginning of chaos.
Authors: Cid Alicia , Díaz Pedro J , Granados Jaime A , Velázquez A Juan M , Zurita Marco A , Mina Alberto , Velázquez Joshua A , del valle Luisa G
Published: October 2022

The purpose of this work was to analyze theoretically and numerically the system of the n pendulum, with n = 2, 3, 4, 5 pendulums. The first corresponds to the classical analysis of the double pendulum, the second case corresponds to the triple pendulum, the third case refers to the quadruple pendulum, finally, the fourth case corresponds to the fivefold pendulum, considering for all cases the same values of mass and length. We obtained the coupled equations of motion for each case using Lagrange´s formulation. Simulations were carried out and equations of motion were solved using Runge Kutta Butcher’s explicit higher-order numerical method. The results of the numerical solution are presented, which show that the movement tends to be chaotic when placing more pendulums to the system. It can also be observed that this is the beginning to study the sections of Poincaré.
Cardiac Acoustic Signal of an unborn baby. A case study.
Authors: Granados Samaniego J , Tavera Romero F , Hernández López RT , Velázquez Arcos J M , Cid Reborido A
Published: October 2022

In medical and laboratory procedures used to obtain useful information to diagnose a disease it is very important not to cause harm to the patient. In the detection of heart disease in fetuses in the mother’s womb, a safe and non-invasive procedure is fetal phonocardiography. In this procedure, an electronic stethoscope captures the sound emitted by the baby’s heart, transforms it into an image and is displayed on a computer screen and a subsequent analysis of that image is performed. This paper shows the procedure to obtain the phonocardiogram of an unborn baby and an algorithm for extracting from it the sounds from the mother’s heart and other physiological noises. The purpose is to recognize if in the acoustic image there are anomalies that allow us to identify congenital or other type lesions in the heart of the fetus.
Propagation of Type II spicules into the solar corona III. MHD simulation
Authors: Díaz-Figueroa E. E. , González-Avilés J. J. , de Parga G. Ares
Published: October 2022

We study the possible influence of a magnetic narrow region on the propagation of jets with some characteristics of Type II spicules into the solar corona using MHD approximation numerical simulations. We found that an increase of temperature occurs mainly at the top of the jet, which supports the idea of sectioning the spicule in the TM approximation of the previous works. Also, we show that the magnetic bottle does not directly affect the propagation of the jet; since the physical conditions of the ideal MHD equations imply that the magnetic field lines are frozen-in with the plasma.