bluuebunny/crossref_metadata_2025 huggingface dataset:
Amphipod assemblages associated with native habitat-forming seaweeds of the Alboran Sea: influence by environmental protection and biogeographical patterns
Authors: Navarro-Barranco Carlos , Lanza-Arroyo Pablo , Gutiérrez-Serrano Jorge , Moreira Juan
Published: October 2022

Context Despite the key ecological role played by epifaunal communities associated with macroalgae in temperate coastal rocky shores worldwide, biodiversity and ecological patterns of their associated invertebrate communities are still poorly known. Aims The present study aims to compare the amphipod assemblages associated with the dominant canopy-forming macroalgae in shallow subtidal habitats of the Alboran Sea, as well as to explore its biogeographical patterns and the influence of protection measures. Methods Replicate samples of both Ericaria selaginoides (=Cystoseira tamariscifolia) and Halopteris scoparia were collected at two different bioregions within the Alboran Sea and both inside and outside marine protected areas. Key results Amphipoda was the dominant taxon within the mobile epifaunal community, both in terms of number of species (47 different species were recorded) and individuals (>70% of the total abundance). Assemblages associated with E. selaginoides and H. scoparia differed and showed a marked response to the Mediterranean–Atlantic gradient in this region; species related to warmer waters become increasingly dominant towards the east. However, there were no significant differences in amphipod assemblage composition, abundance or species richness between protected and non-protected areas. Conclusions Obtained results highlighted the relevance of these native macroalgae as habitat for epifauna, as well as the influence of macroalgal identity and regional biogeographical patterns on amphipod distribution. Implications This study provides valuable baseline information to monitor human-induced changes such as coastal pollution, invasive species, and climate change. It also draws attention about the uncertain response of epifaunal communities to management strategies (such as marine protected areas) and ecological processes (e.g. increasing predation pressure).
Epigenetic analysis of cell-free DNA by fragmentomic profiling
Authors: Zhou Qing , Kang Guannan , Jiang Peiyong , Qiao Rong , Lam W. K. Jacky , Yu Stephanie C. Y. , Ma Mary-Jane L. , Ji Lu , Cheng Suk Hang , Gai Wanxia , Peng Wenlei , Shang Huimin , Chan Rebecca W. Y. , Chan Stephen L. , Wong Grace L. H. , Hiraki Linda T. , Volpi Stefano , Wong Vincent W. S. , Wong John , Chiu Rossa W. K. , Chan K. C. Allen , Lo Y. M. Dennis
Published: October 2022

Cell-free DNA (cfDNA) fragmentation patterns contain important molecular information linked to tissues of origin. We explored the possibility of using fragmentation patterns to predict cytosine-phosphate-guanine (CpG) methylation of cfDNA, obviating the use of bisulfite treatment and associated risks of DNA degradation. This study investigated the cfDNA cleavage profile surrounding a CpG (i.e., within an 11-nucleotide [nt] window) to analyze cfDNA methylation. The cfDNA cleavage proportion across positions within the window appeared nonrandom and exhibited correlation with methylation status. The mean cleavage proportion was ∼twofold higher at the cytosine of methylated CpGs than unmethylated ones in healthy controls. In contrast, the mean cleavage proportion rapidly decreased at the 1-nt position immediately preceding methylated CpGs. Such differential cleavages resulted in a characteristic change in relative presentations of CGN and NCG motifs at 5′ ends, where N represented any nucleotide. CGN/NCG motif ratios were correlated with methylation levels at tissue-specific methylated CpGs (e.g., placenta or liver) (Pearson’s absolute
r
> 0.86). cfDNA cleavage profiles were thus informative for cfDNA methylation and tissue-of-origin analyses. Using CG-containing end motifs, we achieved an area under a receiver operating characteristic curve (AUC) of 0.98 in differentiating patients with and without hepatocellular carcinoma and enhanced the positive predictive value of nasopharyngeal carcinoma screening (from 19.6 to 26.8%). Furthermore, we elucidated the feasibility of using cfDNA cleavage patterns to deduce CpG methylation at single CpG resolution using a deep learning algorithm and achieved an AUC of 0.93. FRAGmentomics-based Methylation Analysis (FRAGMA) presents many possibilities for noninvasive prenatal, cancer, and organ transplantation assessment.
The cosmological vector modes from a monochromatic primordial power spectrum
Authors: Chang Zhe , Zhang Xukun , Zhou Jing-Zhi
Published: October 2022

The cosmological background of higher order vector modes can be generated by the first order scalar perturbations. We investigate the second order and the third order vector modes in a radiation-dominated era systematically. The explicit expressions of two point functions 〈V
(n),λ

V
(n),λ'
〉(n = 2,3) and corresponding power spectra are presented. In the case of a monochromatic primordial power spectrum, the second order vector modes do not exist. However, the third order vector modes can be generated by a monochromatic primordial power spectrum. And it is found that the third order vector modes sourced by the second order scalar perturbations dominate the two point function 〈V
(3),λ

V
(3),λ'
〉 and corresponding power spectra.
Effects of reheating on moduli stabilization
Authors: Alam Khursid , Dutta Koushik
Published: October 2022

Moduli potential loses its minima due to external energy sources of inflaton energy density or radiation produced at the end of inflation. But, the non-existence of minima does not necessarily mean destabilization of moduli. In fact, the destabilization of moduli is always dependent on the initial field values of the fields. In this work, we study carefully how the effects of reheating ease the problem of moduli destabilization. The associated time scale to produce the thermal bath allows a larger initial field range to stabilize the field. Contrary to the usual notion, the allowed initial field range is larger for higher temperatures when the effective potential is of a run-away nature. This eases the moduli destabilization problem for heavy mass moduli. For low mass moduli (≲ 30 TeV), the allowed field range still causes the cosmological moduli problem by violating the BBN constraints unless its initial abundance is suppressed.
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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Biodegradable 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

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.
Effect of Lubricant Viscosity on Wetting Behaviors and Durability of Anti-icing Slippery Liquid-Infused Porous Surfaces
Authors: Xiang Huiying , Yuan Yuan , Zhang Cheng , Zhu Tao , Dai Xu , Liu Guoyong , Song Linbo
Published: October 2022

Icing accretion posed a safety hazard to power lines. Slippery liquid-infused porous surfaces (SLIPSs) are widely used in anti-icing applications. High-viscosity silicone oil has been reported to improve the durability of SLIPS. However, high viscosity can cause problems such as slow self-healing and weak mobility of water droplets on the surface. Herein, the effect of lubricant viscosity on the wetting behavior and durability of anti-icing SLIPS was investigated. The droplet shedding test was conducted to study the durability of SLIPS. The results show that low-viscosity silicone oil can make the prepared SLIPS have good lubricity and low ice adhesion strength, while high-viscosity silicone oil can improve the durability of SLIPS. Under the condition that SA does not exceed 5° and ice adhesion strength does not exceed 10 kPa, 200 cSt silicone oil can make SLIPS simultaneously exhibit excellent slipperiness and durability.
Enhancing conductivity of apatite-type lanthanum silicate by Li and Cu co-doping
Authors: Wang Qichang , Huang Zhiliang , Chen Shi
Published: October 2022

Solid oxide fuel cells (SOFC) are all-solid power generation devices that directly convert chemical energy stored in fuel gases and oxidizers to electrical energy efficiently and without pollution at medium to high temperatures. Recognized as the green energy technology of the 21st century, it is of great significance to alleviating the energy crisis, meeting electricity demand, and reducing environmental pollution. Using the urea-nitrate combustion method, the solid electrolyte powder (LLSCO) of lanthanum silicate of apatite type La9.33LixSi5.5Cu0.5O25.5 + 0.5x (x = 0.1, 0.2, 0.3, 0.4) was successfully prepared by igniting 6-8 mins at 600 °C. According to XRD analysis, LLSCO has a typical P63/m apatite structure and high purity. The volume of LLSCO lattice increases further than that of LSO and LSCO and increases with the increase of Li+ doping. This is because when Li and Cu are doped simultaneously, Li+ enters the empty space in the LSO lattice that occupies the LaII position, which causes the lattice to expand. At the same time, Cu2+ enters the LSO lattice to replace the partial Si4+, which will also cause lattice expansion. The IR analysis shows that Cu2+ replaces Si4+ and enters the [SiO4] tetrahedron to form the [Si(Cu)O4] tetrahedron, while Li+ occupies the vacancy of the LaII position. The optimal sintering temperature of Li and Cu co-doped LLSCO was determined to be 1575 °C based on shrinkage rate, relative density with temperature, and microscopic morphology analysis. The conductivity of La9.33LixSi5.5Cu0.5O25.5+0.5x (x=0.1, 0.2, 0.3, 0.4) was significantly higher than that of LSO and LSCO. With the increase of Li doping, the impedance of the doping sample was lowest when x = 0.3, and the conductivity reached the highest of 9.27 × 10−4 S · cm ·−1 at 600°C.
Preparation of Al and Sm Co-doped Apatite-Type Lanthanum Silicate Electrolyte and analysis of the conductivity mechanism
Authors: Shang Haixin , Chen Changlian , Jiang Yuan , Chen Shi
Published: October 2022

The contradiction between the increasing demand for energy and the scarcity of traditional fossil energy sources is becoming increasingly acute, and it is urgent to accelerate the development and use of new, more efficient, and environmentally friendly energy sources. Apatite-type lanthanum silicate solid oxide electrolyte materials (La9.33Si6O26, LSO) are widely used in the field of fuel cell electrolytes due to their high ionic conductivity and high density. In this paper, Al and Sm co-doped LSO solid electrolytes were successfully prepared by the urea-nitrate combustion method. SEM images, relative density, and linear shrinkage of Al and Sm co-doped lanthanum silicate electrolytes sintered at different temperatures were compared. The results show that the best sintering temperature is 1500°C. The electrical conductivity of La9.33SmxSi5.5Al0.5O25.75+1.5x was analyzed by EIS. The conductivity of La9.33Sm0.2Si5.5Al0.5O26.05 is 2.56 × 10−4 S·cm−1 when measured at 600°C. The reason Al and Sm co-doping enhances the conductance is that Al doping generates oxygen vacancies and increases the interstitial oxygen (Oi) concentration. Doping of Sm not only increases the concentration of Oi but also reduces the concentration of cation vacancies, thus improving the conductivity of the electrolyte.
Ternary Co-Cu Sulfides Deposited on Co-Ni phosphide Decorated Carbon Cloth as Electrode for Supercapacitor
Authors: Dong Xin , Shang Chaoqun
Published: October 2022

With the increasing demand for portable electronic devices, high-capacity supercapacitors have been widely concerned as excellent energy storage devices. Herein, ternary cobalt and copper sulfides (Co-Cu-S) are electrodeposited on the carbon cloth (CC@Ni-Co-P@Co-Cu-S), which is modified by honeycomb-like cobalt and nickel phosphates (Co-Ni-P). The modification of honeycomb-like Ni-Co-P can provide a sufficient active site for the deposition of Co-Cu-S and realize high utilization of Co-Cu-S. Thus, the specific capacity of the supercapacitor is greatly improved. The specific capacity of CC@Co-Ni-P @Co-Cu-S is 0.85 F cm−2, quintupling that of CC@Co-Cu-S, and the capacity remains 94.3% after 100 cycles. In addition, CC@Co-Ni-P@Co-Cu-S has the best electrochemical performance when Co-Cu-S was deposited for eight cycles. This study fully demonstrates that Co-Ni-P modification greatly improves the specific capacity of the CC@Co-Cu-S electrode.
Electric Energy Storage System Modelling for Power System Dynamic Analysis in Multi-time Scale
Authors: Huang Xiaofan , Cheng Sibo , Ge Chenchen , Jing Xuye , Wang Guangpei , Shao Wenchuan , Zheng Hua
Published: October 2022

Battery energy storage systems (BESSs) have been widely promoted for implementation as a solution to the frequency stability challenges in the modern power system. To analyze the dynamic response of a power system accurately and efficiently, an appropriate BESS model should be developed. In this paper, based on the BESS full-order model, the BESS reduced-order model is proposed according to the time scale of interest. And the proposed simplified model is classified according to its complexity and usage of the proposed simplified model. Finally, the accuracy of the proposed simplified model in different scenarios was verified by comparing it with the BESS full-order model in the MATLAB-based Simulink.
A novel test technology for a standardized stability control system and its test platform
Authors: Xu Biao , Xu Liqiang , Xu Yuxin , Li Bo , Ouyang Fan , Huang Yong , Ao Fei
Published: October 2022

The stability control system is the second defense line of the power system, and the test before applying the stability control system is a key link to ensure the performance of the system. Since the configuration and strategy of the standardized stability control system are related through the setting of fixed value items, it is necessary to comprehensively consider the coupling between different application scenarios, different operation modes, and different stability control strategies to verify the functions of each device. Starting from the design concept and function of the standardized stability control system, this paper introduces the test scheme of the standardized stability control system from three aspects: monomer test, static test, and strategy verification test. Besides, the test platform of the stability control system based on RTDS is built, which lays the foundation for the stability control test and ensures that the standardized stability control system meets the requirements of regulations and specifications.
Grounding fault location of large turbo generator based on stator winding distribution
Authors: Xu Yuxin , Xu Biao , Huang Yong , Ouyang Fan , Ao Fei
Published: October 2022

Stator grounding is the most common fault of a large generator. If the accurate coil of the fault can be located quickly and effectively, the maintenance progress of the generator can be greatly sped up, and the fault generator can be put back into use as soon as possible. For this purpose, a stator grounding fault location method for a large steam generator is proposed, which takes the distribution of winding potential into account. Firstly, the fault characteristics and the influence of winding potential distribution are analyzed when a single-phase ground fault occurs in a large generator, and the amplitude equation and phase equation of zero sequence voltage are constructed. On this basis, the potential distribution of stator winding can be analytically expressed, so the fault location can be directly calculated by the numerical solution method. Simulation analysis verifies the effectiveness of the proposed method.
Short-term Forecast of EV Ownership in Shanghai Based on Metabolic GM(1,1)-Markov Model
Authors: Dong Ran , Sun Lijiang
Published: October 2022

The reasonable forecast of Electric Vehicle (EV) ownership is conducive to grasping the market development and determining the development goals of EVs. In addition, predicting the scale of EVs is conducive to analyzing the impact of EV charging on power grid load and guiding the construction of EV charging stations and other infrastructure. In view of the low amount of EV ownership data over the years in Shanghai, an improved grey model(GM)-Markov prediction method is proposed to predict the ownership of EVs. Firstly, several sets of data at recent time points are selected and the metabolic GM(1,1) replaces the original GM model for data fitting. After obtaining the fitting results, a group of data with the highest fitting accuracy was selected to establish the Markov correction model. Secondly, the Markov correction model is established for the highest fitting accuracy data. The sample mean-standard deviation method is used to divide the state matrix, and the interval partition criterion is dynamically adjusted to fit the relative error distribution probability, which avoids certain subjectivity. Compared with the original model, the relative error of fitting results decreases from 4.780% to 0.764%, and the prediction accuracy of the modified model is further improved. Finally, the ownership of EVs in Shanghai by the Metabolic GM(1,1) -Markov model in the next three years is forecasted, and the ownership of EVs in Shanghai is expected to exceed 1 million in 2023.
PV hosting capacity evaluation method in distribution network considering overvoltage risk
Authors: Yao Di , Lu Yu , Zhang Dachi , Shi Shengyao , Zhu Meng , Zhang Bo
Published: October 2022

To address the problems of limited analysis scenarios in mathematical optimization methods and conservative assessment in random scenario simulation methods, this paper first introduces the concept of overvoltage risk and proposes an overvoltage risk-based PV capacity assessment method for distribution networks. Based on this method, the severity of overvoltage is further considered, and the overvoltage risk index is improved by introducing correction coefficients. The assessment results obtained from this method can better reflect the real overvoltage risk level of the distribution network, which is more adaptable and meaningful for actual PV capacity planning. Finally, a practical 55-bus distribution system in a region of China is used as an example to verify the adaptability and effectiveness of the proposed method.
Review on mechano-electronic device fault diagnosis based on Hilbert-Huang Transformation
Authors: Lu Zhiqi
Published: October 2022

This paper reviews the new Hilbert-Huang Transformation (HHT for short) signal processing method, briefly discusses the significance of time-frequency analysis methods in electromechanical system fault diagnosis, points out the superiority of HHT for fault diagnosis with respect to the characteristics of nonstationary and nonlinear dynamic fault signals, and introduces the basic principles of HHT. The research applications of HHT in the field of fault diagnosis at home and abroad are discussed, showing that HHT is becoming an important signal processing method for mechanical fault diagnosis.
Design and Simulation Analysis of High Power Density Superboost Circuit
Authors: Fu Beinan , Lu Zhiqi , Xu Mochen , Dong Baolei , Liu Tao
Published: October 2022

A battery discharge regulator system based on the Superboost converter is presented, and the working principle of the Superboost converter is analyzed. In order to meet the developing requirements of high efficiency and high power density converters, GaN devices are applied to the Superboost circuit to increase the switching frequency of the circuit. Thanks to this, the weight and volume of the passive devices can be reduced, and the power density of the circuit can be increased. In high-frequency conditions, the device parameters of the circuit are designed, and the theoretical derivation of the circuit transfer function is carried out. Finally, simulation software is used to verify the rationality and feasibility of the design.
Research on High-Frequency Current Partial Discharge Monitoring Technology of Transmission Lines
Authors: Liu Lanlan , He Zhiqiang , Niu Jie , Li Bocheng , Li Sijin , Dong Guiling , Wang Zhenyu
Published: October 2022

Partial discharge (PD) in transmission lines is one of the main causes of line breakdown. At present, PD monitoring is at the technical level and cannot be real-time and accurate monitoring. In this paper, a novel PD monitoring technology is designed by combining a high-frequency current sensor (HFCT) with traditional methods, which can not only accurately and quickly determine the leakage position, but also control the loss of inline transmission. In addition, based on the realization of partial discharge monitoring, this paper proposes a local signal denoising method, to distinguish between partial discharge monitoring of pure noise signal and local signal pulse discharge signal, and improve the efficiency and reliability of the monitoring equipment, the test results show that the sensor was carried out on the common discharge disfigurement detection, location, and recognition, and can be measured through the signal to assess the degree of danger.
A Device for Test and Evaluation of Consistency of Power Battery Pack for Automotive applications
Authors: Wang Hongwei , Zheng Chun , Liu Jun , Fu Yanling , Xi Guangchen , Yang Wanshan
Published: October 2022

In this paper, the thermal consistency and electrochemical performance of batteries were comprehensively considered to improve the test and ensure the consistency of the power battery pack for automotive applications. At the same time, a safer and more efficient device IS established for testing and evaluation of battery consistency for automotive applications to achieve the real-time monitoring, assessment, prediction, and control of its consistency.
A Virtual Power Plant Operating Approach for Steelworks
Authors: Gao Yanghe , Ji Jie , Liang Mingliang , Tan Xiandong , Zheng Haifeng , Yao Li , Xue Wanlei
Published: October 2022

The production process of steel can be divided into two processes: from ironstone to steel (long process) or from steel scrap to steel (short process). As for short process, through the automatic control system, the electric arc furnace (EAF) can be temporarily shut down to realize the load regulation, which helps to maintain power balance during the peak load period. In this paper, Virtual Power Plant (VPP) is considered to aggregate steelworks to participate in demand response project. By studying the production process of steelworks, we build an optimization model which maximizes the net revenue of VPP with satisfying the operating constraints. The performance of the proposed model is validated using a VPP which is composed of four steelworks with 10 EAFs.
Analysis of Electric Field Distribution of Insulators YD-JZ 10 kV Oil-Immersed Transformers
Authors: Feng Qi , Shao Zhenhua
Published: October 2022

The electric field distribution of the YD-JZ 10 kV oil-immersed transformer insulator is analyzed by COMSOL simulation, calculation, and actual measurement methods. The result shows that the first shed of the insulator accounts for 18% of the voltage drop. After that, the voltage of each umbrella skirt decreased gradually, and the proportion of voltage drop of the last two umbrella skirts increased again. The electric field of the insulator tip burr is 1.16 × 106 V/m; spherical burr is 2.84 × 105 V/m. The simulation result shows that the maximum electric field of spherical air gap defect in an insulator is 1.38 × 105 V/m; conical air gap defect is 1.61 × 105 V/m ; metal particle defect is 1.49 × 105 V/m. The simulated insulator umbrella skirt is covered with water. When the whole insulator umbrella skirt is short-circuited, there may be ground discharge. The measured results and simulation results show that the insulator can work normally if the umbrella skirt is not completely short-circuited.
Optimizing energy conservation of central heating systems based on temperature stratified water tank
Authors: Li Min , Bu Bing , Wang Yifei , Zhang Huan
Published: October 2022

In this paper, the central heating system is taken as the main research object. The finite volume method was used to optimize the number of internal partitions, the height of the partitions, and the position of the partitions in the hot water storage water tank. The influence of temperature stratified water tank with optimized structure and fully mixed water tank on the central heating system is also analyzed. The results show that the temperature stratified water tank is more energy efficient in heating than the fully mixed water tank. The study enriches the relevant part of energy storage in central heating systems and is of guidance for heating engineering projects.
Evaluation method considering rural new energy utilization
Authors: Luo Fan , Liang Chen , Ma Xiping , Li Yaxin , Dong Xiaoyang
Published: October 2022

Nowadays, it is indispensable for the establishment of a rural new energy utilization rating system, but the current evaluation system has shortcomings that it does not consider the subjective and objective impact, and cannot further select the best when the evaluation grades are the same. In this regard, we establish a new evaluation system for the utilization of new energy in rural areas considering the shortcomings listed above. A control item evaluation is established first according to the actual situation in rural areas and the relevant national standards. Once the item meets the standards, a general item evaluation will be conducted. In the general item evaluation, the subjective and objective weights are calculated using analytic hierarchy processes and entropy weighting methods, and the combined weight is determined through calculation. Then, each evaluation scheme is classified according to the matter-element extension analysis method. To obtain a better scheme, a fuzzy comprehensive evaluation is used when the evaluation level is the same. This paper provides a method that accounts for the subjectivity and objectivity of the evaluation object, classifies evaluation indicators, and resolves the issue of the same evaluation grade that can no longer be evaluated.