bluuebunny/crossref_metadata_2025_split huggingface dataset:
Time-dependent expansion of a weakly-collisional plasma beam in a paraxial magnetic nozzle
Authors: Zhou J , Sánchez-Arriaga G , Ahedo E 
Published: March 2021

Abstract
The transient and steady-state expansion of a weakly-collisional plasma beam in a paraxial magnetic nozzle is studied with a kinetic Boltzmann–Poisson model. Only intraspecies collisions involving electrons are considered and these are modeled with a Bhatnagar–Gross–Krook operator. Simulations show that occasional collisions progressively populate the phase-space region of isolated trapped electrons until a steady state is reached, which is independent of transient history. The steady state is characterized by a partial occupancy of that region increasing with the collisionality rate but far away from the full occupancy postulated by an alternative steady-state kinetic model. The changes on the amount of trapped electrons with the collisionality rate explain, in turn, the changes on the spatial profiles of main plasma magnitudes. Conclusions on the momentum and energy balances of ions and electrons agree, in terms of general trends, with those of the steady-state kinetic model. In the downstream region of the expansion, ions and electrons lose all their perpendicular energy but they still keep part of their parallel thermal energy. Electron heat fluxes of parallel energy are not negligible and are approximately proportional to enthalpy fluxes.
An improved conversion of the microwave energy into plasma in an optimized microwave plasma sheet source at 2.45 GHz designed for surface treatment
Authors: Miotk Robert , Jasiński Mariusz , Mizeraczyk Jerzy 
Published: March 2021

Abstract
Efficient conversion of the microwave energy into an atmospheric-pressure argon plasma in a microwave plasma sheet source (MPSS) operating at 2.45 GHz in ambient air is the subject of this work. The MPSSs, capable of providing an atmospheric pressure plasma in the shape of a narrow sheet are an innovative technology for variety of surface treatments with no impact on the environment. The existing designs of the MPSS exhibit unsatisfactory efficiency of the conversion of microwave energy produced by the microwave source into the microwave plasma (about 80%), which hinders implementation of the MPSSs in the industry. In this paper, after an analytical approach based on the equivalent electrical circuit method we proposed an optimization of the design of MPSS in terms of the microwave energy conversion efficiency. The MPSS design improvement consisted in reducing the electrical impedance in the input plane of the MPSS by introducing a capacitive diaphragm into the MPSS transmission line, which compensated the inductive character of the plasma sheet. The experimental measurement of the electrodynamic characteristics of the MPSS with diaphragm showed that using the diaphragm significantly decreased the microwave power losses due to the microwave reflection from about (20–30)% to a level of several percent. This substantially increased the MPSS energy conversion efficiency up to about 97%, 93% and 87% for incident powers P
I of 500 W, 750 W and 1000 W, respectively. The electrodynamic characteristics of the MPSS appeared a very convenient tool for determining the conditions of maximum efficiency of conversion of the microwave energy into the microwave plasma. The electrodynamic characteristics were measured at argon flow rate of 20 Nl min−1. The analysis of the calculated input impedances of the MPSSs with and without diaphragm, based on the equivalent electrical circuits of both MPSSs confirmed that the change of the character of the input reactance of the MPSS from inductive to capacitive after introducing the diaphragm is the cause of the increase in the MPSS energy conversion efficiency. The MPSSs having the energy conversion efficiency such high as presented in this paper appears to be attractive innovative technology for economic use in industrial applications.
Optimal system, symmetry reductions and group-invariant solutions of (2+1)-dimensional ZK-BBM equation
Authors: Tanwar Dig Vijay 
Published: March 2021

Abstract
The present article intends to generate optimal system of one dimensional subalgebra and group–invariant solutions of ZK–BBM equation with the aid of Lie group theory. The ZK–BBM equation is long wave equation with large wavelength, which describes the water wave phenomena in nonlinear dispersive system. The infinitesimal vectors, commutative relations and invariant functions for optimal system of ZK–BBM equation are derived under invariance of Lie groups. The invariance property leads to the reduction of independent variable and leaves the system invariant. Based on the optimal system, ZK–BBM equation is transformed into ordinary differential equations by twice reductions. These ODEs are solved under parametric constraints and result into invariant solutions. The obtained solutions are analyzed physically based on their numerical simulation. Consequently, elastic multisoliton, dark and bright lumps, compacton and annihilation profiles of the solutions are well presented graphically.
The Lyman Alpha Spectral Database (LASD)
Authors: Runnholm Axel , Gronke Max , Hayes Matthew 
Published: March 2021

Abstract
Lymanα (Lyα) emission from star-forming galaxies is an important tool to study a large range of astrophysical questions: it has the potential to carry information about the source galaxy, its nearby circumgalactic medium, and also the surrounding intergalactic medium. Substantial observational and theoretical work has therefore focused on understanding the details of this emission line. These efforts have been hampered, however, by an absence of spectroscopic reference samples that can be used both as comparisons for observational studies and as critical tests for theoretical work. For this reason, we have compiled a large sample of Lyα spectra, at both low and high redshift, and created a publicly available online database, at lasd.lyman-alpha.com. The Lyman Alpha Spectral Database (LASD) hosts these spectra, as well as a large set of spectral and kinematic quantities that have been homogeneously measured for the entire sample. As part of this we have developed an automated redshift determination algorithm which we show is accurate to within less than ±180 kms−1 on average, across many different Lyα profiles. The measurements can conveniently be viewed online and downloaded in tabular form. The LASD has the capacity for users to easily upload their own Lyα spectra, and all the same spectral measurements will be made, reported, and ingested into the database. We actively invite the community to do so, and the LASD is intended to be a long-term community resource. In this paper we present the design of the database as well as descriptions of the underlying algorithms and the initial Lyα emitter samples that are in the database.
Controllable Goos–Hänchen shift and optical switching in an Er3 + -doped yttrium aluminum garnet crystal
Authors: Chen Xiu-Mei , Shui Tao , Meng Chun , Zhang Tong , Deng Xu , Yang Wen-Xing 
Published: March 2021

Abstract
We propose an efficient scheme to control Goos–Hänchen (GH) shifts of the reflected and transmitted beams in a cavity containing Er3 + -doped yttrium-aluminum-garnet (YAG) crystal with a four-level Er3 +  ionic system. It is found that both the values and signs of the reflected and transmitted GH shifts can be coherently controlled by tuning the relevant optical parameters, such as the incoherent pumping rate, and the intensity and detuning of the driving field. Furthermore, we propose a scheme for such a configuration of the reflected GH shift as a family of reflection-type optical switchings. It is shown that the average port spacing and reflectivity of the optical switching can reach approximately 1.03 mm and 16.88, respectively, which indicate the high performance of switching function. Our proposal may provide a possibility to implement optically tuned optical switching.
ASH: an Automatic pipeline to generate realistic and individualized chronic Stroke volume conduction Head models
Authors: Carla Piastra Maria , van der Cruijsen Joris , Piai Vitória , Jeukens Floor E M , Manoochehri Mana , Schouten Alfred C , Selles Ruud W , Oostendorp Thom 
Published: March 2021

Abstract

Objective. Large structural brain changes, such as chronic stroke lesions, alter the current pathways throughout the patients’ head and therefore have to be taken into account when performing transcranial direct current stimulation simulations. Approach. We implement, test and distribute the first MATLAB pipeline that automatically generates realistic and individualized volume conduction head models of chronic stroke patients, by combining the already existing software SimNIBS, for the mesh generation, and lesion identification with neighborhood data analysis, for the lesion identification. To highlight the impact of our pipeline, we investigated the sensitivity of the electric field distribution to the lesion location and lesion conductivity in 16 stroke patients’ datasets. Main results. Our pipeline automatically generates 1 mm-resolution tetrahedral meshes including the lesion compartment in less than three hours. Moreover, for large lesions, we found a high sensitivity of the electric field distribution to the lesion conductivity value and location. Significance. This work facilitates optimizing electrode configurations with the goal to obtain more focal brain stimulations of the target volumes in rehabilitation for chronic stroke patients.
Hybrid asynchronous brain–computer interface for yes/no communication in patients with disorders of consciousness
Authors: Huang Jianyong , Qiu Lina , Lin Qianmin , Xiao Jun , Huang Yuanqiu , Huang Haiyun , Zhou Xinjie , Shi Xiangyu , Wang Fei , He Yanbin , Pan Jiahui 
Published: March 2021

Abstract

Objective. For patients with disorders of consciousness (DOC), such as vegetative state (VS) and minimally conscious state (MCS), communication is challenging. Currently, the communication methods of DOC patients are limited to behavioral responses. However, patients with DOC cannot provide sufficient behavioral responses due to motor impairments and limited attention. In this study, we proposed a hybrid asynchronous brain–computer interface (BCI) system that provides a new communication channel for patients with DOC. Approach. Seven patients with DOC (3 VS and 4 MCS) and eleven healthy subjects participated in our experiment. Each subject was instructed to focus on the square with the Chinese words ‘Yes’ and ‘No’. Then, the BCI system determined the target square with both P300 and steady-state visual evoked potential (SSVEP) detections. For the healthy group, we tested the performance of the hybrid system and the single-modality BCI system. Main results. All healthy subjects achieved significant accuracy (ranging from 72% to 100%) in both the hybrid system and the single modality system. The hybrid asynchronous BCI system outperformed the P300-only and SSVEP-only systems. Furthermore, we employed the asynchronous approach to dynamically collect the electroencephalography signal. Compared with the synchronous system, there was a 21% reduction in the average required rounds and a reduction of 105 s in the online experiment time. This asynchronous system was applied to detect the ‘yes/no’ communication function of seven patients with DOC, and the results showed that three of the patients (3 MCS) not only showed significant accuracies (67 ± 3%) in the online experiment, and their Coma Recovery Scale-Revised scores were also improved compared with the scores before the experiment. This result demonstrated that 3 of 7 patients were able to communicate using our hybrid asynchronous BCI system. Significance. This hybrid asynchronous BCI system can be used as a useful auxiliary bedside tool for simple communication with DOC patients.
Optimizing thermal block length during infrared neural inhibition to minimize temperature thresholds
Authors: Ford Jeremy B , Ganguly Mohit , Zhuo Junqi , McPheeters Matthew T , Jenkins Michael W , Chiel Hillel J , Jansen E Duco 
Published: March 2021

Abstract

Objective. Infrared neural inhibition (INI) is a method of blocking the generation or propagation of neural action potentials through laser heating with wavelengths strongly absorbed by water. Recent work has identified that the distance heated along axons, the block length (BL), modulates the temperature needed for inhibition; however, this relationship has not been characterized. This study explores how BL during INI can be optimized towards minimizing its temperature threshold. Approach. To understand the relationship between BL and the temperature required for INI, excised nerves from Aplysia californica were laser-heated over different lengths of axon during electrical stimulation of compound action potentials. INI was provided by irradiation (λ = 1470 nm) from a custom probe (n = 6 nerves), and subsequent validation was performed by providing heat block using perfused hot media over nerves (n = 5 nerves). Main Results. Two BL regimes were identified. Short BLs (thermal full width at half maximum (tFWHM) = 0.81–1.13 mm) demonstrated that increasing the tFWHM resulted in lower temperature thresholds for INI (p < 0.0125), while longer BLs (tFWHM = 1.13–3.03 mm) showed no significant change between the temperature threshold and tFWHM (p > 0.0125). Validation of this longer regime was performed using perfused hot media over different lengths of nerves. This secondary heating method similarly showed no significant change (p > 0.025) in the temperature threshold (tFWHM = 1.25–4.42 mm). Significance. This work characterized how the temperature threshold for neural heat block varies with BL and identified an optimal BL around tFWHM = 1.13 mm which minimizes both the maximum temperature applied to tissue and the volume of tissue heated during INI. Understanding how to optimally target lengths of nerve to minimize temperature during INI can help inform the design of devices for longitudinal animal studies and human implementation.
Critical points in the RP

N−1 model
Authors: Diouane Youness , Lamsen Noel , Delfino Gesualdo 
Published: March 2021

Abstract
The space of solutions of the exact renormalization group fixed point equations of the two-dimensional RP

N−1 model, which we recently obtained within the scale invariant scattering framework, is explored for continuous values of N ⩾ 0. Quasi-long-range order occurs only for N = 2, and allows for several lines of fixed points meeting at the Berezinskii–Kosterlitz–Thouless transition point. A rich pattern of fixed points is present below N* = 2.244 21‥, while only zero temperature criticality in the O(N(N + 1)/2 − 1) universality class can occur above this value. The interpretation of an extra solution at N = 3 requires the identification of a path to criticality specific to this value of N.
Probability density of fractional Brownian motion and the fractional Langevin equation with absorbing walls
Authors: Vojta Thomas , Warhover Alex 
Published: March 2021

Abstract
Fractional Brownian motion and the fractional Langevin equation are models of anomalous diffusion processes characterized by long-range power-law correlations in time. We employ large-scale computer simulations to study these models in two geometries, (i) the spreading of particles on a semi-infinite domain with an absorbing wall at one end and (ii) the stationary state on a finite interval with absorbing boundaries at both ends and a source in the center. We demonstrate that the probability density and other properties of the fractional Langevin equation can be mapped onto the corresponding quantities of fractional Brownian motion driven by the same noise if the anomalous diffusion exponent α is replaced by 2 − α. In contrast, the properties of fractional Brownian motion and the fractional Langevin equation with reflecting boundaries were recently shown to differ from each other qualitatively. Specifically, we find that the probability density close to an absorbing wall behaves as P(x) ∼ x

κ
with the distance x from the wall in the long-time limit. In the case of fractional Brownian motion, κ varies with the anomalous diffusion exponent α as κ = 2/α − 1, as was conjectured previously. We also compare our simulation results to a perturbative analytical approach to fractional Brownian motion.
Mechanical properties improvement in an advanced automotive steel
Authors: Duran-Núñez A , Aburto-Perdomo E , Hernandez-Garcia P , Ramírez-Ledesma A L , Juárez-Islas J A 
Published: March 2021

Abstract
Due to the increase in environmental and safety regulations that have been applied worldwide, the automotive industry has seen the need to develop steel alloys whose mechanical properties perform, not only reliably, but at a low cost. This is why the study of the third – generation steel has taken a defining position in the industry; due to the high mechanical properties, it offers and the advantages that will be reflected in the production of vehicles. In this sense, this study proposes an alternative to traditional materials, which not only reduces costs but also meets the characteristics required by the market based on two different processing routes: 1) hot – rolling + water quenching (HR + WQ), and 2)hot – rolling + water quenching + sub-zero treatment (HR + WQ + ST).
Irreversibility and First and Second Law Efficiencies Analysis in three different Solar Cookers Box-Type
Authors: Terres H , Chávez S , Lizardi A , López R , Vaca M , Lara A , Morales J 
Published: March 2021

Abstract
This work shows the results and evaluation of three box-type solar cookers. The cooker designs are octagonal, rectangular and square. Irreversibility, first and second law results are obtained considering the water heating process. These values indicate that the rectangular design has the highest efficiency values, although it does not have the highest temperature values. It is shown how the area of the glass cover of the cookers influences its efficiency since the increase in this value is not reflected in an improvement in efficiency. The effect of irreversibility and its impact over the second-law efficiency when the water heating process increases in the solar cookers are explained. The results are very useful because they allow us to assess the potential ranges of exergy when it is applied to energy devices such as solar cookers, which can contribute to the design and improvement of solar devices with the same characteristics.
Mechano-optical analysis of piezoelectric hydroxyapatite composites
Authors: Islas-García E , Torres-San Miguel C , García-Merino J 
Published: March 2021

Abstract
The piezoelectric behavior of Hydroxyapatite (HAp) composites by the mechanical action of high optical irradiances was studied. The piezoelectric and optical properties of HAp composites were considered based on previous researches. Using a finite method element and computational software, is obtained a numerical approximation of mechanical deformation by using a direct current voltage as input. It was considered a mechano-optical model to reproduce a normal force acting on the surface of the HAp composites provided by a nanosecond pulsed laser irradiation. The generated voltage was estimated under high optical irradiance using a proposed mathematical approach. This study can assist in the characterization of piezoelectric crystals by noninvasive disturbances. These results exposed the possibility of developing novel measurement procedures that involve nonlinear optical processes.
Energetic, Exergetic and Entropy Evaluation in the Solar Distillation
Authors: Chávez S , Terres H , Lizardi A , López R , Lara A , Vaca M 
Published: March 2021

Abstract
This work shows the evaluation of energy, exergy and entropy for the process of solar distillation of river water. The solar still is of the slope with fins and is tested for 3 initial volumes: 2, 4 and 6 L, for which data of temperature and solar radiation are recorded. Subsequently, the Dunkle’s thermal model is applied and the energy, exergy and entropy balance are established to determine the efficiencies. The results show that the maximum energy efficiency in the solar still for 2, 4 and 6 L is 45%, 36% and 30% respectively, in exergy efficiency its maximum values are 4.7%, 3.8% and 2.9% for 2, 4 and 6 L of river water and finally the analysis of the entropy change, reached the maximum value of 1 kJ/Kg K in the 3 experimental tests.
A device inspired by the mantis shrimp’s strike to produce cavitation bubbles on solid surfaces
Authors: Godínez F A , Guzmán J E V , Valdés R , Chávez O , De La Rosa K G , Cruz S 
Published: March 2021

Abstract
We discuss a low-cost mechanical device designed to generate cavitation bubbles through the impact of rigid surfaces. The process is triggered by a pivoting limb, which develops speeds as high as 180 rad/s (9 m/s) while submerged in water. A mathematical model is proposed to describe the limb’s dynamics whose results are in good agreement with the experimental data. The model shows that more than 65 % of the elastic-potential energy to power the limb is dissipated by drag/friction effects. This key aspect must be considered when developing efficient devices for applications such as lithotripsy.
Multiwavelength confocal fiber optic microscopy
Authors: Sosa-Acosta J A , Sánchez-Pérez C A 
Published: March 2021

Abstract
We present a multiwavelength fiber optic confocal microscope (MCFOM) based on the use of a wide spectral emission light source and some commercially available fiber optic components to make a reliable and compact system. We use single mode fiber optics SMF-28 to illuminate and collect the reflected light from the sample avoiding the use of a pinhole as a filter for the unfocused planes; as well as two lenses to collimate the light. The chromatic aberration produced by the lenses is used to interrogate several planes simultaneously, eliminating the confocal scanning movement obtaining an average confocal resolution of 4 μm and a surface scanning resolution of 1 μm. We demonstrated enough sensitivity to scan biological samples with a depth of penetration of 26 μm showing the potential use of this proposal in research laboratories as an alternative low cost confocal microscopy.
Neural network within a Bayesian inference framework
Authors: Gómez-Vargas Isidro , Esquivel Ricardo Medel , García-Salcedo Ricardo , Vázquez J Alberto 
Published: March 2021

Abstract
In Bayesian inference, the likelihood functions are evaluated thousands of times. In this paper we explore the use of an Artificial Neural Network to learn how to calculate the likelihood function and thus speed up the Bayesian inference process. We test the performance of the neural network on a parameter estimation of the standard cosmological model and show that this method can reduce the computational time.
Comparative study of the optical response in thin films of CdS:In
Authors: Molina J , Horta S D , Espejo-Bayona L , Castillo S J , Avila D A 
Published: March 2021

Abstract
In this investigation, thin films of indium-doped CdS and CdS were synthesized using the chemical bath deposition technique. These thin films were characterized by optical transmission, optical reflection, diffraction index and optical band gap. The optical spectra reveal that the optical transmission response increases with the concentrations of indium and the refractive index decreases. The CdS:In samples with 1cM, 2cM and 3cM the optical band gap is 2.50 eV, 2.74 eV, and 2.90 eV respectively.