bluuebunny/crossref_metadata_2025 huggingface dataset:
Observing ice structure of micron-sized vapor-deposited ice with an x-ray free-electron laser
Authors: Kim Seonmyeong , Sattorov Matlabjon , Hong Dongpyo , Kang Heon , Park Jaehun , Lee Jae Hyuk , Ma Rory , Martin Andrew V , Caleman Carl , Sellberg Jonas A , Datta Prasanta Kumar , Park Sang Yoon , Park Gun-Sik
Published: August 2023

The direct observation of the structure of micrometer-sized vapor-deposited ice is performed at Pohang Accelerator Laboratory x-ray free electron laser (PAL-XFEL). The formation of micrometer-sized ice crystals and their structure is important in various fields, including atmospheric science, cryobiology, and astrophysics, but understanding the structure of micrometer-sized ice crystals remains challenging due to the lack of direct observation. Using intense x-ray diffraction from PAL-XFEL, we could observe the structure of micrometer-sized vapor-deposited ice below 150 K with a thickness of 2–50 μm grown in an ultrahigh vacuum chamber. The structure of the ice grown comprises cubic and hexagonal sequences that are randomly arranged to produce a stacking-disordered ice. We observed that ice with a high cubicity of more than 80% was transformed to partially oriented hexagonal ice when the thickness of the ice deposition grew beyond 5 μm. This suggests that precise temperature control and clean deposition conditions allow μm-thick ice films with high cubicity to be grown on hydrophilic Si3N4 membranes. The low influence of impurities could enable in situ diffraction experiments of ice nucleation and growth from interfacial layers to bulk ice.
Inverse design of optical correlation induced effects
Authors: Luo Meilan , Ornigotti Marco , Koivurova Matias
Published: August 2023

A comprehensive theoretical framework for the inverse design of correlation induced effects with optical beams is introduced. Correlation induced effects are able to modify the intensity distribution of an optical beam drastically via effects such as correlation induced splitting, focusing, and shifting. The inverse design steps are given analytically, which allows the analysis of several related experiments. Finally, an algorithm for more complex numerical inverse design is overviewed and demonstrated.
Development of primary reference facilities and measurement comparison of standard artifacts for the bidirectional transmittance distribution function
Authors: Fu J. , Quast T. , Velke E. , Esslinger M. , Pastuschek M. , Schirmacher A. , Aschan R. , Manoocheri F. , Ikonen E.
Published: August 2023

To determine the bidirectional transmittance distribution function (BTDF) of diffusely transmitting materials, two new primary facilities have been developed at the Physikalisch-Technische Bundesanstalt (PTB) and Aalto University (Aalto). A detailed description of both facilities and the different approaches used are presented in this paper. The performance of both facilities is compared by determining the BTDF of two different diffuser types in both in-plane and out-of-plane bidirectional geometries at four different wavelengths in the visible spectral range. Due to delayed completion of PTB’s primary facility, the measured BTDF values are compared between Aalto’s primary facility and another PTB setup, whose measurement scales are successfully transferred to PTB’s primary facility by an internal comparison. A thorough analysis of the measurement uncertainty is presented, leading to a combined k = 1 standard uncertainty of 0.8%–1.2% for PTB’s primary facility and 1.3%–1.7% for Aalto’s primary facility. The BTDF results obtained agree well within their expanded k = 2 uncertainty. This indirect bilateral comparison shows that Aalto’s and PTB’s new facilities are suited as primary reference setups for the determination of the BTDF. These studies also reveal action points to improved measurement capabilities and for a reduction of the measurement uncertainty, depending on the type of diffuser under test.
High-temperature photon-type ultra-broadband detectors based on ratchet structure
Authors: Li X. H. , Huang S. H. , Yu Q. , Yuan X. , Liu Y. , Bai P. , Song W. J. , Bai H. Z. , Xu G. Y. , Shen W. Z. , Zhang Y. H.
Published: August 2023

Achieving a photodetector with high bandwidth, high sensitivity, high speed, and high operating temperature is a common goal for researchers, especially for infrared and terahertz regions due to its important application in various fields like military defense and biochemical analysis. Among photon-type terahertz (THz) detectors, heterojunction interfacial work function internal photoemission (HEIWIP) detectors demonstrate high bandwidth, high sensitivity, and high speed, but are limited by the low operating temperature. In this work, we developed an effective strategy for raising its operating temperature by introducing ratchet structures. By comparing with traditional HEIWIP, the ratchet HEIWIP exhibits a low dark current and high detectivity while retaining the ultra-broad response bandwidth. The operating temperature has been raised from 7 to 20 K in the terahertz region, which is meaningful progress in THz photon-type detection. The universality of this scheme makes it possible to be further migrated to general photon-type semiconductor detectors.
Interfacial coupling and dopant-induced electronic modulation enabling Mn–CoP/MXene heterostructures to reduce alkaline HER energy barriers
Authors: Guo Manman , Lian You , Yuan Yuxi , Yu Ting , Qu Yaohui , Yuan Cailei
Published: August 2023

Electronic structure modulation is a promising strategy to reduce energy barriers of hydrogen evolution reaction (HER). We have constructed 3D monodispersed Mn doped CoP nanoflowers supported on MXene sheets (Mn–CoP/MXene) to boost the alkaline HER kinetics, and the enhanced mechanisms were clarified by photoelectron spectroscopies tests and density functional calculations. The Mn doping and MXene coupling resulted in the modulated electronic structure and, thus, improved active sites for balancing the free energy of H2O dissociation and *H intermediates. The HER activity has been strengthened by the synergy of Mn doping and MXene coupling with an overpotential of only 95 mV to 10 mA cm−2, a ultra-small Tafel slope of 54.1 mV dec−1, and outstanding stability in 1.0 M KOH electrolyte. This work highlights the potential of the synthetic strategy of heteroatom doping and 2D materials coupling to be extended to prepare advanced and cost-effective TMPs-based electrocatalysts.
Fluorine and related complexes in α-Al2O3
Authors: Choi Minseok , Van de Walle Chris G.
Published: August 2023

Using first-principles calculations based on hybrid-density-functional theory, we examine the energetics and electronic structure of fluorine in α-Al2O3. The F atom can be incorporated as an interstitial (Fi) or substitutional impurity on the oxygen site (FO); the latter tends to be lower in energy, particularly under Al-rich conditions. Fluorine on the oxygen site acts as a donor, but for Fermi-level positions high in the bandgap, a negatively charged DX configuration is lower in energy. Fluorine substituting on the Al site is not energetically stable. We also examine complexes between F and hydrogen or carbon, which can easily be unintentionally incorporated during growth or processing. Our calculated defect levels, combined with band alignments, allow us to assess the impact on Al2O3/semiconductor heterostructures. We find that F can passivate oxygen-vacancy related traps in the Al2O3 dielectric. Complex formation with H or C is either ineffective or could even be detrimental.
Lagrangian dynamics of particle transport in oral and nasal breathing
Authors: Seyedzadeh Hossein , Oaks Wayne , Craig Jonathan , Aksen Mustafa , Sanz Mario Sánchez , Khosronejad Ali
Published: August 2023

We present a large-eddy simulation (LES) of saliva particle transport during normal human breathing through the nose and mouth. The flow of the air–saliva mixture is modeled using an Eulerian LES that is coupled with a Lagrangian particle tracking module to obtain trajectories of saliva particles in a room with stagnant air conditions. The coupled Eulerian–Lagrangian simulation yields novel insights into the intricate dynamics of Lagrangian coherent structures (LCS) and fundamental material lines that emerge from the saliva particles' trajectories during several breathing cycles. Further, we systematically compare the quantitative LCS diagnostics of mouth breathing with those of mouth and nose normal breathing. Analyzing the simulation results of human breathing from the mouth and nose, we show that, soon after the first breathing cycle, saliva particles form a series of roll-up vortex rings that propagate forward. The forward propagation of these vortex rings leads to the formation of an asymmetrical primary forefront vortex. The individual vortex rings continuously propagate forward, merging with the forefront vortex, and ascending along the limb of the leading vortex.
Reactive oxygen species are regulated by immune deficiency and Toll pathways in determining the host specificity of honeybee gut bacteria
Authors: Guo Lizhen , Tang Junbo , Tang Min , Luo Shiqi , Zhou Xin
Published: August 2023

Host specificity is observed in gut symbionts of diverse animal lineages. But how hosts maintain symbionts while rejecting their close relatives remains elusive. We use eusocial bees and their codiversified gut bacteria to understand host regulation driving symbiotic specificity. The cross-inoculation of bumblebee
Gilliamella
induced higher prostaglandin in the honeybee gut, promoting a pronounced host response through immune deficiency (IMD) and Toll pathways. Gene silencing and vitamin C treatments indicate that reactive oxygen species (ROS), not antimicrobial peptides, acts as the effector in inhibiting the non-native strain. Quantitative PCR and RNAi further reveal a regulatory function of the IMD and Toll pathways, in which
Relish
and
dorsal-1
may regulate
Dual Oxidase
(
Duox
) for ROS production. Therefore, the honeybee maintains symbiotic specificity by creating a hostile gut environment to exotic bacteria, through differential regulation of its immune system, reflecting a co-opting of existing machinery evolved to combat pathogens.
Throughput-scalable manufacturing of SARS-CoV-2 mRNA lipid nanoparticle vaccines
Authors: Shepherd Sarah J. , Han Xuexiang , Mukalel Alvin J. , El-Mayta Rakan , Thatte Ajay S. , Wu Jingyu , Padilla Marshall S. , Alameh Mohamad-Gabriel , Srikumar Neha , Lee Daeyeon , Weissman Drew , Issadore David , Mitchell Michael J.
Published: August 2023

Lipid nanoparticles (LNPs) are a potent delivery technology that have made it possible for the recent clinical breakthroughs in mRNA therapeutics and vaccines. A key challenge to the broader implementation of mRNA therapeutics and vaccines is the development of technology to produce precisely defined LNP formulations, with throughput that can scale from discovery to commercial manufacturing and meet the stringent manufacturing standards of the pharmaceutical industry. To address these challenges, we have developed a microfluidic chip that incorporates 1×, 10×, or 256× LNP-generating units that achieve scalable production rates of up to 17 L/h of precisely defined LNPs. Using these chips, we demonstrate that LNP physical properties and potency in vivo are unchanged as throughput is scaled. Our chips are fabricated out of silicon and glass substrates, which have excellent solvent compatibility, compatibility with pharmaceutical manufacturing, and can be fully reset and reused. SARS-CoV-2 mRNA-LNP vaccines formulated by our chips triggered potent antibody responses in a preclinical study. These results demonstrate the feasibility of directly translating microfluidic-generated LNPs to the scale necessary for commercial production.
The structural basis of hyperpromiscuity in a core combinatorial network of type II toxin–antitoxin and related phage defense systems
Authors: Ernits Karin , Saha Chayan Kumar , Brodiazhenko Tetiana , Chouhan Bhanu , Shenoy Aditi , Buttress Jessica A. , Duque-Pedraza Julián J. , Bojar Veda , Nakamoto Jose A. , Kurata Tatsuaki , Egorov Artyom A. , Shyrokova Lena , Johansson Marcus J. O. , Mets Toomas , Rustamova Aytan , Džigurski Jelisaveta , Tenson Tanel , Garcia-Pino Abel , Strahl Henrik , Elofsson Arne , Hauryliuk Vasili , Atkinson Gemma C.
Published: August 2023

Toxin-antitoxin (TA) systems are a large group of small genetic modules found in prokaryotes and their mobile genetic elements. Type II TAs are encoded as bicistronic (two-gene) operons that encode two proteins: a toxin and a neutralizing antitoxin. Using our tool NetFlax (standing for Network-FlaGs for toxins and antitoxins), we have performed a large-scale bioinformatic analysis of proteinaceous TAs, revealing interconnected clusters constituting a core network of TA-like gene pairs. To understand the structural basis of toxin neutralization by antitoxins, we have predicted the structures of 3,419 complexes with AlphaFold2. Together with mutagenesis and functional assays, our structural predictions provide insights into the neutralizing mechanism of the hyperpromiscuous Panacea antitoxin domain. In antitoxins composed of standalone Panacea, the domain mediates direct toxin neutralization, while in multidomain antitoxins the neutralization is mediated by other domains, such as PAD1, Phd-C, and ZFD. We hypothesize that Panacea acts as a sensor that regulates TA activation. We have experimentally validated 16 NetFlax TA systems and used domain annotations and metabolic labeling assays to predict their potential mechanisms of toxicity (such as membrane disruption, and inhibition of cell division or protein synthesis) as well as biological functions (such as antiphage defense). We have validated the antiphage activity of a RosmerTA system encoded by
Gordonia
phage Kita, and used fluorescence microscopy to confirm its predicted membrane-depolarizing activity. The interactive version of the NetFlax TA network that includes structural predictions can be accessed at
http://netflax.webflags.se/
.
Longitudinal diffusion barriers imposed by myofilaments and mitochondria in murine cardiac myocytes
Authors: Deisl Christine , Chung Jay H. , Hilgemann Donald W.
Published: August 2023

Using optical and electrical methods, we document that diffusion in the cytoplasm of BL6 murine cardiomyocytes becomes restricted >20-fold as molecular weight increases from 30 to 2,000, roughly as expected for pores with porin channel dimensions. Bodipy-FL ATP diffuses >40-fold slower than in free water at 25°C. From several fluorophores analyzed, bound fluorophore fractions range from 0.1 for a 2 kD FITC-labeled polyethylene glycol to 0.93 for sulforhodamine. Unbound fluorophores diffuse at 0.5–8 × 10−7 cm2/s (5–80 μm2/s). Analysis of Na/K pump and veratridine-modified Na channel currents suggests that Na diffusion is nearly unrestricted at 35°C (time constant for equilibration with the pipette tip, ∼20 s). Using multiple strategies, we estimate that at 35°C, ATP diffuses four to eight times slower than in free water. To address whether restrictions are caused more by protein or membrane networks, we verified first that a protein gel, 10 g% gelatin, restricts diffusion with strong dependence on molecular weight. Solute diffusion in membrane-extracted cardiac myofilaments, confined laterally by suction into large-diameter pipette tips, is less restricted than in intact myocytes. Notably, myofilaments extracted similarly from skeletal (diaphragm) myocytes are less restrictive. Solute diffusion in myocytes with sarcolemma permeabilized by β-escin (80 µM) is similar to diffusion in intact myocytes. Restrictions are strain-dependent, being twofold greater in BL6 myocytes than in CD1/J6/129svJ myocytes. Furthermore, longitudinal diffusion is 2.5-fold more restricted in CD1/J6/129svJ myocytes lacking the mitochondrial porin, VDAC1, than in WT CD1/J6/129svJ myocytes. Thus, mitochondria networks restrict long-range diffusion while presumably optimizing nucleotide transfer between myofilaments and mitochondria. We project that diffusion restrictions imposed by both myofilaments and the outer mitochondrial membrane are important determinants of total free cytoplasmic AMP and ADP (∼10 μM). However, the capacity of diffusion to deliver ATP to myofilaments remains ∼100-fold greater than ATP consumption.
Build-up dynamics of different pulse types in a dispersion-managed Yb-doped fibre laser
Authors: Wu Yunfeng , Gao Ziqi , Zhang ZeXin , Liu Haiyan , Tian Jinrong , Song Yanrong
Published: August 2023

We present a dispersion-managed mode-locked ytterbium fibre laser based on the nonlinear polarization evolution technique. Four single-pulse states could be generated by changing group delay dispersion values from anomalous (−0.0038 ps2) to normal (0.051 ps2) with a grating pair. In the normal dispersion regime, the pulse width was gradually decreased with the decrease of the net dispersion. In the anomalous dispersion region, the typical soliton was obtained, which time-bandwidth product could be calculated as 0.526. In addition, the dynamics of four states were also investigated by using the dispersive Fourier transformation technique. Different pulse evolution dynamics were observed from chaotic state to mode-locking.
Neural Network based Transmission Line Fault Classifier and Locator using Sequence Values
Authors: Idris Muhd Hafizi , Adzman Mohd Rafi
Published: August 2023

Faults can easily occur at transmission line because the line is exposed to the environment. The fast fault location after a fault occurrence will minimize the time to repair the faulty part thus reduce the stress of power system due to long outage time. This paper demonstrates the development of fault classifier and fault locator using neural network. The positive, negative and zero sequence values of three-phase voltage and current during fault time were used as the inputs to train the neural networks. Various fault conditions which have different fault types, fault resistance values and fault locations have been simulated to generate the training data for both neural network based fault classifier and fault locator. From the results, the fault classifier and locator successfully classified and located all the simulated fault conditions. One of the advantages of using sequence values as the inputs for the neural networks is only one fault type need to be simulated and used as the training data for single line-to-ground fault (RG, YG and BG), line-to-line fault (RY, YB, BR) and double line-to-ground fault (RYG, YBG, BRG).
Loss minimization in Quadratic Boost Converter Multilevel Inverter fed induction motor system by Tuning of FOPID controller using PSO
Authors: Umadevi D , Shivakumar E G
Published: August 2023

Particle swarm optimization algorithm (PSO) is suggested to discover fractional order PID (FOPID) controller optimal variables for a better performance of induction motor. This PSO algorithm is designed to handle multiple optimization issues, due to its ease of application. A Closed Loop Quadratic Boost Converter Multilevel Inverter Fed Induction Motor (QBCMLIIM) system is simulated to earn reduced switching losses and reduced THD by incorporating particle swarm optimization(PSO) tuned Fractional Order PID controller. PSO stands to be one of the popular Artificial Intelligence (AI) method. The PSO algorithm starts its process from the initial particles by allotting initial velocities to the particles. At each location the objective function and the corresponding best values are evaluated. The double loop feedback system enhances the performance and robustness by suppressing the oscillations and overshoots.
PCB Rogowski Coil sensor by using Saw blade pattern for arcing fault detection
Authors: Khalid K.A. , Fahmi M.I. , Nanyan A.N. , Bohari Z.H.
Published: August 2023

Rogowski is a special current transformer and has been categorised as a low-power stand-alone current sensor. This sensor is designed by using a Saw blade pattern with 50 turns and 100 turns. This number of turns will impact the increment of the sensitivity of the sensor. Rogowski coil is used for measuring the alternating current (AC) and high-speed current pulses. The PCB Rogowski Coil will detect the arcing fault that design with AutoCAD software after that import to CST software. An arc is created when the electrical current jumps the gap between two conductive materials. The most common causes of arcs include worn contacts in electrical equipment, damage to insulation, break in a cable and loose connections. In order to reduce the arc fault risk, the arc fault interrupter (AFI) technology and arc fault detectors (AFD) have been developed. However, these devices are most suitable for domestic application or low voltage (LV). This paper proposed a simulation using AutoCAD and CST software to design a Rogowski coil and the Rogowski Coil sensor will be tested by using CST software in terms of radiation pattern. The biggest radiation pattern in red colour is the saw blade pattern in 100 turns at 2 KHz frequency, the radiation pattern covering entire sensor area compared with other radiation patterns with other frequency. The main lobe magnitude for 2 KHz frequency is 46.8 dB, main lobe direction is 180 deg, angular width is 153.4 deg and the side lobe level is zero. This is the best number of turn and frequency compared to 50 turn saw blade sensor.
Explicit Solution of Parameter Estimate using Multiparametric Programming for Boost Converter
Authors: Mid E C , Mukhtar N M , Syed Yunus S H , Hadi D A , Ruslan E
Published: August 2023

This work proposes an approach to estimate the parameters of capacitance and inductance in a boost converter using an explicit solution. A multiparametric programming (MPP) algorithm is fundamental to the suggested methodology, which aims to develop parameters as explicit functions of measurements. In this method, the generalised mathematical model of the boost converter is discretised into an algebraic equation. The parameter estimation problem is then formulated and solved using Karush-Kuhn-Tucker. Finally, an explicit solution of estimate parameters such as capacitor and inductor is formulated as an explicit function of the inductor currents and capacitor voltage. Finally, the state variables of the boost converter are numerically obtained and used to test the capability of the proposed work. The results presented in this work prove the MPP algorithm can estimate the boost converter’s parameters, which can be extended to other power converters and filters.
Supercapacitor’s Parameter Calculation based on Three Branch Equivalent Circuit Model under Different Constant Charging Current
Authors: Jabbar M. Abdul , Fahmi M. I. , Yaakob SB , Liew H F , Khan MDSA
Published: August 2023

Supercapacitor is a type of energy storage with higher capacitance value compared to the normal capacitor. But it has lower voltage level compared to normal capacitor. However, it can be charged with high current and provide higher current to the load when needed when compared to the same size energy storage such as battery. The Three Branch Equivalent Circuit is one of the simple yet accurate model that has been proposed. The parameter of the Three Branch model included the capacitance, resistance and a unit of voltage dependent capacitance. The Parameter needed to be calculated accurately as it depends heavily on the terminal voltage of the supercapacitor at respective time which obtained through a charging and self-discharging experiment under constant current charging. The different constant charging current give effect toward the parameter calculation as it manipulates the rate of charging and self-discharging. This paper will calculate the parameter of supercapacitor based on the Three Branch model under different constant charging current and compared the result using the simulation to show the accuracy of the model. The parameter obtained throughout the study shows a high accuracy especially the parameters obtained using higher charging current.
Drone Detection using Ultrasonic Sensors for Passive Forward Scattering Radar System
Authors: Abdul Aziz N H , Mahadi M A A , Mohd Noh Z , Othman K A
Published: August 2023

Passive Forward Scattering Radar (PFSR) is a great system that can be used to identify ground moving targets, especially in unsafe areas for reason such as protection and security. Although PFSR can detect any moving target, there are some limitations as PFSR cannot measure height and detect small target such as a drone flying in the sky. A drone is a good device based on the latest technologies, therefore it can also be very dangerous as it can fly in the sky entering prohibited areas that can, for example, breach a border protection system. By developing a system using ultrasonic range sensor interfacing with Raspberry Pi (RPi) and also implementing Internet of Things (IoT) using mobile phone application, which is Telegram, as a security alarm system, this system can integrate with PFSR to be a better system. This project aims to improve the PFSR system with an ultrasonic range sensor remote measuring device. When set up next to the PFSR system, the ultrasonic range sensor has large distance measurement capabilities and use low power to operate. Since ultrasonic range sensors cannot work by themselves, the RPi was used as an operating host that helped to operate and collect data. Then, the data collected was saved into Comma Separated Values (CSV) files to be sent to Telegram mobile application later to the user as notification. The data collected from both systems were compared in order to relate that the ultrasonic range sensor system can indeed support the PFSR system. Since the result was obtained and analysis was done successfully, it can be concluded that the system can support the PFSR system, whereby as the drone height (cm) increased, the signal captured in time (sec) decreased. In addition, this system can contribute in many areas such as borders or streets, to detect speed of vehicles or as a traffic surveillance system and for some other reasons such as protection, security and research.
Cooling Pipe Network System in the Quenching Green Equipment Design Method Based on the “Solid Contact-Fluid Heat Transfer” Mode
Authors: Zhang Hongchen , Chen Peng , Bai Shuowei , Wang Qing , Ju Junwei , Wang Yuqi
Published: August 2023

As a typical thin plate part, a circular saw blade matrix is prone to deformation and cracking due to uneven surface cooling rate during heat treatment. Simultaneously, the traditional quenching method is easy to produce a low product qualification rate and serious environmental severe when processing thin plate parts. The quenching device designed in this paper is to achieve the non-contact quenching between the processed parts and the quenching medium through the heat transfer of the fluid in the cooling pipe. The structure design of the internal cooling channel will directly affect the temperature field distribution of the quenching device, thus determining the microstructure and final performance of the product. Therefore, based on the microstructure transformation mechanism and pipe network flow control theory, combined with the heat transfer theory and other relevant theoretical bases, this paper established the mathematical model of internal cooling system parameters. Finally, MATLAB is applied to solve the fluid network topology model. It provides a reliable and general research method for cooling pipe networks in quenching devices based on the “Solid Contact-Fluid Heat Transfer” Mode.
Influence of nozzle structure and process parameters for 3D printing HTPB-based propellant
Authors: Song Shixiong , Ren Quanbin , Shi Jiawei , Shi Hongbin
Published: August 2023

This paper studies the influence of nozzle structure and process parameters on the solid propellant 3D printing process, so as to better guide nozzle structure optimization and process improvement, and realize continuous extrusion and molding of solid propellant. Four characteristic parameters such as nozzle diameter, nozzle shrinkage angle, process temperature, and wall slip coefficient are selected, and the influence of these four parameters on the extrusion speed and pressure of solid propellant slurry in the nozzle is discussed by using the orthogonal test principle and ANSYS/POLYFLOW. The results show that the most significant factor affecting the outlet velocity uniformity index and outlet pressure is the wall slip coefficient, followed by the nozzle diameter, and the influence of temperature and contraction angle is small.
Mechanical Friction Simulation and Optimization Design of Floating Bearing of Mechanical Tricone Bit
Authors: Lei Ming , Peng Fang , Zhang Shiqiang , Zheng Junyuan , Wang Weihua , Ying Wu , Kong Xiangrui
Published: August 2023

This paper aims to find out the most vulnerable position and the suitable clearance ratio of the floating sleeve between the inside and outside floating sleeve of the tricone bit. In this paper, the mechanical analysis model of the drill bit is established to get the simulated working condition of the tri-cone bit, and then the stress condition of the floating bearing is simulated. Finally, the multi-factor variable orthogonal test method is used to optimize the clearance ratio of the floating sleeve. The results show that the simulation results are consistent with the wear position of the floating sleeve: during the operation of the floating sleeve, the most vulnerable position is the edge position, the largest deformation is the opening position, the recommended internal clearance of the floating sleeve is 0.06–0.07 mm, the recommended external clearance is 0.02–0.04 mm, and the recommended internal clearance ratio is 2.0–2.4.
Interference Assembly Stress of Wheel-Axle in B-type Subway
Authors: Tong Yao , Tian Chun
Published: August 2023

This paper aims to improve the reliability of train operation as well as to guarantee the safety of wheelset interference assembly. A finite element model of the wheel-axle interference fit is established with a metro B-type car as the research object. The finite element calculation software is used to simulate the static strength of the wheel-axle model under different working conditions, contact spots, and maximum/minimum interference. The effect of different interference and different working conditions on contact stress is studied. The study shows that the wheel meets the static strength requirements under all working conditions. The maximum equivalent stresses are located at the wheel hub bore under the maximum or minimum interference assembly. The full curved condition with maximum interference is the most dangerous condition among the working conditions.
The Model Reduction Method of Grouped Blades
Authors: Zheng Zhaoli , Zhao Zhenxing , Yang Xiaohu , Cao Guangming , Wu Jun
Published: August 2023

As an important structure in turbine machinery, grouped blades are easy to damage due to large thermal loads and centrifugal loads. Once the characteristic frequency of grouped blades is equal to or close to the frequency of the exciting forces, the vibration of the grouped blades will become very severe. Therefore, it is very important to analyze the characteristic frequency of grouped blades accurately and quickly. This article aims to investigate the model reduction method of grouped blades, which can reduce the unknowns in the dynamic equations of grouped blades. And the efficiency of the modal analysis of grouped blades can be improved. Finally, the effects of the modal truncation number on the error of the natural frequency, the modal shape confidence factor, and the calculation time are discussed. Although the structure discussed in this paper is the disk with three blades, the derived algorithm can be applied to large-scale grouped blades. The study of this paper can serve as a reference for the design and validation of the widely used blade groups in the industry.
Mining Machines for Comprehensive Mechanized Mining of Bauxite
Authors: Wang Zhenqian , Zhang Liqiang
Published: August 2023

The mining machine for bauxite is the key equipment for the mechanized mining of underground bauxite ore. The mining machines for shearing and loading bauxite ore have been studied in this paper from three aspects: the determination of key technical parameters, the in-situ tests, optimization, and improvement. Mechanical and physical parameters of bauxite ore, such as high tensile strength, no-cleavage, and abrasion properties, have a great impact on the determination of key technical parameters of the mining machine. The conventional conical picks which are widely used in mining equipment drums for soft rock, such as coal mines, are not suitable for bauxite and other high-abrasion ore rocks. The chisel pick is theoretically a better choice. The main faults of the mining machine for bauxite during the in-situ tests are closely related to the high abrasion of bauxite rock, especially for the abrasion of conical picks and the walking actuator of the traction part. So the second-generation mining machine should be optimized from the selection of types, linear speed, and cutting depth of picks, from selecting wear-resistance material for the walking actuator of the traction part and designing a more suitable structure for the walking actuator of the traction part. The research results have important theoretical significance for the design of mining machines for bauxite.
Electrostatic layer jamming variable stiffness based on AC waveform regulation
Authors: Wu Xiongxiong , Lu Ben , Liao Ningbin , Jia Wenchuan , Sun Yi
Published: August 2023

As a method to achieve variable stiffness of soft robots, electrostatic layer jamming (ELJ) has the disadvantages of low breakdown strength and a single stiffness control method. In this paper, we propose to replace the air of the traditional ELJ device with giant electrorheological fluid (GERF) and introduce the method of adjusting the stiffness by AC waveform to solve these problems. We perform friction experiments on ELJ devices (ELJ-GERF, ELJ-Air, ELJ-Oil) under three different dielectrics of GERF, air, and silicone oil. The results show that the breakdown probability of ELJ-Air increased significantly when the applied voltage is greater than 3000 V, while ELJ-GERF and ELJ-Oil can withstand voltage exceeding 5000 V. ELJ-GERF has higher breakdown strength than ELJ-Air. At the same time, the AC waveform can regulate the stiffness of the three devices. By applying voltages with three different AC waveforms (sine wave, square wave, and triangle wave), all three devices exhibit different stiffness properties. The stiffness of ELJ-GERF is increased by 2.6 times, 4.5 times, and 2.7 times under the sine wave, square wave, and triangular wave respectively compared with DC voltage. The other two devices also have a certain increase in stiffness.
The study of ionic conductivity of the Li10GeP2S12 type Solid State Electrolyte by an extrapolation method and a deep-learning method
Authors: Peng Jie , Du Jianwen , Wang Liping
Published: August 2023

An extrapolation method is usually applied when Ab initio molecular dynamics (AIMD) is applied to studying ionic conductivity in solid-state electrolytes in lithium-ion batteries. As the ions move slowly in solid-state electrolytes, the first-principles method typically involves computationally intensive calculations, and it can take significant time to obtain accurate results. First-principles method is too expensive for the time scale required at room temperature. The classical molecular dynamics method is typically applied to systems containing thousands of atoms and can simulate the system’s behavior over nanoseconds. During the simulation, the positions and velocities of the atoms are updated at discrete time intervals, allowing the system’s behavior to be studied over time. However, its accuracy depends on the empirical force-field libraries. Limited by the computational resource, the previous studies applied the extrapolation method to obtain the room temperature ionic conductivity, which was not accurate because the linear relationship in the Arrhenius equation was not valid in a wide range of temperatures. Deepmd-Kit is a tool that integrates these two different computational approaches. The extrapolation and Deepmd methods were applied to the materials Li10GeP2S12, Li10SiP2S12, Li10GePS12Cl, and Li10SiPS12Cl, respectively. Both methods showed that the lithium ions favor the c direction when diffusing in the LGPS-type solid-state electrolytes. The ionic conductivity is more accurate with the dependent method compared with experiments.
Optimised Design for High-speed Solenoid Valves with Dual Coils
Authors: Zhang Zichen
Published: August 2023

Aiming at the dynamic performance of the solenoid valve for the injection molding machine and the mutual constraint of coil heat generation in the process of energization, a control method of the solenoid valve for the injection molding machine with series start and parallel hold is proposed. A two-coil solenoid valve is designed, and a basic simulation model of the solenoid valve is built using COMSOL finite element simulation software, and numerical calculations are performed for the conventional solenoid valve for the injection molding machine and the two-coil solenoid valve, respectively. The results show that in the process of opening, holding, and closing the valve, the response speed of opening the valve is increased by 87.9%, the response speed of closing the valve is increased by 75%, and the coil heat generation is reduced by 14.3% during holding by reducing the height of the moving iron core during holding.
Experimental study on anti-loosening technology of transmission line bolts
Authors: Li Qinghua , Li Maohua , Wu Jing , Liu Yaduo , An Ping
Published: August 2023

Bolts are widely used in transmission lines and are key connecting parts of transmission lines. Transmission lines have been affected by the natural environment for a long time, and bolts are prone to frequent vibration leading to loosening or falling off. Bolt loosening endangers the safe and stable operation of transmission lines. This paper analyses the loosening mechanism of the transmission line screw connection, carries out the transverse vibration contrast test of the common bolt anti-loosening measures, and develops the integrated self-locking double nut for the hidden danger of the transmission line bolt loosening, which has good anti-loosening performance, convenient installation, and the conditions for engineering popularization and application.
Application of electrical resistivity tomography (ERT) for vertical high-density polyethylene (HDPE) membrane detection
Authors: Chang Jingrun , Nai Changxin , Qiu Panpan , Zhang Luyu
Published: August 2023

At landfill sites, uncontrolled leachate is a serious cause of groundwater and soil contamination at landfills and can occur extensively when there are looploopholesin the vertical HDPE (High-density polyethylene) membrane. For this reason, detecting HDPE membranes is necessary. The conventional electrode running poles approach is limited, it reflects the distribution of resistivity in 2D subsurface profiles, which is difficult to deploy electrodes above vertical HDPE membrane. According to the structural characteristics and field conditions of vertical HDPE membranes, the two-row current and potential (CP) electrode array is proposed to be applied to the testing of vertical HDPE membranes. The forward geoelectric model of the vulnerability was built using pyGimli, and data on 1519 apparent resistivity were acquired. The previous knowledge without the vulnerability was taken into consideration as the constraint condition, and the regional control was added to conduct the inversion, all using the least square approach. The model was used to analyze data on the detection of vertical HDPE membranes in a landfill In Yancheng, and potential flaws were discovered. Results show that the CP electrical measuring device can be efficient, quick, and accurate in the positioning of vertical HDPE membrane hole detection, and it is a cost-effective method. To verify the results, in the vertical HDPE membrane, through the Wenner device, the inversion of the 2D profile, and low resistivity anomalies are detected. This is thought to be through the leachate of leakage of HDPE membrane resistance rate is about 1.8 ohm. The findings demonstrate that the vertical HDPE membrane susceptibility may be located and detected using a CP electrical measuring instrument, which is a practical and efficient approach.
Constitutive Equation and Processing Map of CoCrFeNiMo0.3 High Entropy Alloy Based on The Thermoplastic Deformation
Authors: Wei Menghan , Zhao Hui , Zhang Yu , Lu Yang , Li Mei
Published: August 2023

The unique characteristics of high entropy alloys are challenging the field of traditional materials science and are expected to apply innovations in fields such as aerospace and defense, making them one of the strong candidates. The thermoplastic deformation mechanisms and processing maps of CoCrFNiMo0.3 alloy were studied at a temperature (T) ranging from 950 - 1250 °C and a strain rate (

ε
˙

) ranging from 0.001 - 0.1 s−1. A sharp rise is observed in the flow curve in the early stage, as the strain increases, slowly increasing flow stress due to the presence of dynamic softening, then turns to decrease, finally reaches a steady state. The optimal processing area was at 1050 - 1250 °C and 0.001 - 0.1 s−1, and there is an unstable area appearing at 950 - 1050 °C and 0.01 - 0.1 s−1. The η in the hot processing region are high, and they are not in the instability region.
Finite Element Strength Analysis and Optimization of Cutting Tools Based on Fluid-Structure Interaction
Authors: Cui Yanhao , Peng Liang , Liu Chang , Hu Yi , Chen Zhenlei
Published: August 2023

In this paper, taking a cutting tool as an example and aiming at the problem of cutting tool stress and fatigue evaluation and optimization, a finite element model including the tool, shaft, and washer was established by using the methods of simulation and testing, and the stress and strain analysis of the tool in the working process was completed. A single fluid-structure coupling method was applied to calculate the dynamic load of the cutting tool in the process of high-speed food cutting, and ABAQUS was used to analyze the stress and strain under this load. Practical engineering applications showed that the method was practical and feasible, and the calculation results were consistent with the actual measurements. The established analytical model can accurately reflect the real working conditions of the tool, and the stress and fatigue of the key parts of the tool can be quantitatively assessed, providing a reference for the optimal design of the tool.
Restitution coefficient of various particles based on acoustic technology
Authors: Chai Yinfu , Zhong Wenzhen , Yang Chao , Shi Xinlin , Zhao Qingxin
Published: August 2023

The restitution coefficient is used to characterize the energy loss in particle impact, which is an important parameter for discrete element simulation and mechanical system motion analysis. However, the restitution coefficient of many materials needs to be determined, and the key material properties affecting the restitution coefficient are still unclear. In this paper, the acoustic frequency sampling method was used to study the restitution coefficients of 10 representative particles. The effects of material density and specific strength on the restitution coefficient and the relationship between the restitution coefficient and the damping coefficient were investigated. The results show that the particle restitution coefficient is inversely proportional to the density except for aluminium. The relationship between particle restitution coefficient and specific strength is not significant.
Design of foot-wheel cooperation walking assistance robot and control method for human-robot coordination movement
Authors: Li Junqiang , Liu Huanhuan , Yan Yanlai , Yang Dong
Published: August 2023

To meet the walking demand of people who is less able to exercise, a foot-wheel cooperation walking assistance robot is designed, a control method of human-robot coordination movement is proposed, and then the walking on-the-wheel system is realized. Firstly, the structure of the foot-wheel cooperation walking assistance robot is designed, the kinematics of human lower limbs is analyzed, and the movement relationship between the foot system and wheel system is established. Secondly, the control methods of the foot system and wheel system are studied respectively, composite control method is used to realize the function that the motion of the human foot is followed by the pedal. Based on the user’s walking information and the motion relationship between the foot system and the wheel system, the coordinated motion control of the foot system and the wheel system is realized. Finally, an experimental prototype of foot-wheel cooperation walking assistance robot is developed, then the foot-wheel cooperation walking assistance experiment is completed. Experimental results show that the function of walking on the wheeled system can be realized by the proposed human-robot coordination movement method.
The Seismic Response of Ultra-High Voltage Gas-Insulated Transmission Lines
Authors: Lv Wei , Zhang Lihong
Published: August 2023

As an important part of the substation, the seismic capacity of ultra-high voltage (UHV) electrical equipment is related to the safe and stable operation of the substation and the whole power grid. The UHV gas-insulated transmission lines (GIL) have many structural characteristics, such as long pipeline distance, the large span between supports and the obvious amplification effect of supports. Its natural frequency is close to the predominant frequency of the seismic wave, resulting in its susceptibility to resonance or resonance-like and high seismic susceptibility. In order to analyze the seismic performance of UHV GIL better, the vibration mode decomposition response spectrum method and the dynamic time-history analysis method are used to analyze the seismic response of UHV GIL in this paper. The search for seismic weak positions of GIL is a reference for effectively improving the seismic performance of UHV GIL.
Solidification process of the triple-tube latent heat storage system with novel tree-like fin
Authors: Liu Fei , Zhang Guanmin
Published: August 2023

Traditional rectangular fins will cause the area between the two fins to be difficult to heat and become a “dead zone”. In this paper, inspired by the shape of branches, a novel tree-shaped fin is put forward to promote the heat release property TTLHSS. The exotherm process of TTLHSS with rectangular fins and tree fins is numerically calculated by using Ansys Fluent software. In addition, the TTLHSS liquid fraction diagram, liquid fraction change curve, average temperature, heat release time, and total heat release were analyzed. The novel fin can significantly improve the heat release property of TTLHSS and accelerate the exotherm rate. Compared with the TTLHSS with straight fins, the PCM absolute solidification time in the TTLHSS with new tree-like fins is decreased by 43.1%, and the full heat release is slightly increased. This study provides the direction for the fin design of TTLHSS.
Working fluids for low-temperature waste heat from coal-fired unit for the Organic Rankine Cycle (ORC)
Authors: Cai Jianming , Liu Xin , Chen Linfeng , Ren Jianxing
Published: August 2023

With the process of industrialization, a lot of energy is consumed, and a lot of low-grade energy is produced in the process. To recover low grade heat energy from flue gas of coal-fired power plants, the organic Rankine cycle is built and improves energy utilization efficiency. Taking six working fluids, R245ca, R245fa, R123, R600, R601, and R600a, as an example, referring to the exhaust gas condition of a 300MW subcritical coal-fired unit, analysed the evaporation temperature on the net work and thermal efficiency and exergy efficiency, the influence of electricity production cost (EPC) and payback period (PBP). The results show that the net work of R123 is the largest with the same conditions, which improves the system performance. At an evaporation temperature of 400K with the objective of reaping the economic benefit, R245ca and R601 as equivalent values are able to be used in engineering.