bluuebunny/crossref_metadata_2025 huggingface dataset:
The Relationship between a Rotational Molding Processing Procedure and the Structure and Properties of Biobased Polyethylene Composites Filled with Expanded Vermiculite
Authors: Aniśko Joanna , Barczewski Mateusz , Piasecki Adam , Skórczewska Katarzyna , Szulc Joanna , Szostak Marek
Published: August 2022

Rotational molding is a technology in which polymeric thin-walled products can be made. The newest descriptions of this technology concern the possibility of obtaining polymer composite materials. There are two main methods of incorporating fillers into a polymer matrix. Dry blending is based on mixing fillers with polymer powders before rotational molding by hand or using automatic mixers. In the melt compounding method, fillers are mixed with the polymer in the preliminary step by melt processing and then grinding or pulverization to obtain polymer powders for rotational molding. This work aimed to investigate the impact of the processing procedure on the structure and properties of biobased composites with expanded vermiculite. Produced rotomolded parts were examined using mechanical tests to assess changes in tensile, flexural, and impact properties. The most significant difference in mechanical properties was noted for samples with 10 wt% expanded vermiculite (EV). The elasticity modulus increases by almost 2 fold when the sample is prepared in a two-step process, the tensile strength is 4-fold higher, the flexural modulus is 3-fold higher, and the flexural strength is 5-fold higher. We also investigated thermomechanical properties in DMA measurement. The void volume content was also measured to control the quality of obtained parts. The porosity of dry blended samples containing more than 2 wt% EV is almost 2-fold higher. Other methods to control quality and structure were optical and scanning electron microscopy used for rotomolded parts and polymer powders. The investigations of rotomolded parts were supplemented with a complete description of used materials, including the particle size distributions of polymer powders and filler. Analysis of the thermal properties and chemical structure was also performed despite all the mechanical tests. The emerging conclusions from the research clearly show that the two-step process allows for achieving a more beneficial mechanical performance of the composites made of the biobased polymer in rotational molding technology.
The Mechanical Properties of Gangue Paste Material for Deep Mines: An Experimental and Model Study
Authors: Leng Qiang , Chang Qingliang , Sun Yuantian , Zhang Biao , Qin Jianzhuang
Published: August 2022

Gangue paste material is mainly composed of coal gangue with particle size, which is mixed with cement. Fly ash and additives can be added to change its performance. In this paper, the influence of each component on the mechanical properties of gangue paste material was studied by an orthogonal experiment. The conversion relationship among various indexes of mechanical properties of gangue paste material and the response surface prediction model were discussed. The results show that the mechanical properties of gangue paste materials are positively correlated with the content of cement, the content of fly ash and the mass concentration, which increase with the increase of the three factors, and show the primary and secondary relationship of the content of cement > the content of fly ash > the mass concentration. A response surface prediction model of mechanical property parameters is established, which includes the first order term of the influencing factors of gangue paste material and the first order interaction term between any two factors. In the response surface prediction model of uniaxial compressive strength, splitting tensile strength, cohesion and elastic modulus, the goodness of fit test coefficients are 0.998, 0.957, 0.970 and 0.997, respectively, which proves that the model has good goodness of fit. The research results provide basic parameters for paste filling mining practice, and also provide the basis for numerical simulation of filling body value.
Synthesis and Property Examination of Er2FeSbO7/BiTiSbO6 Heterojunction Composite Catalyst and Light-Catalyzed Retrogradation of Enrofloxacin in Pharmaceutical Waste Water under Visible Light Irradiation
Authors: Luan Jingfei , Liu Wenlu , Yao Ye , Ma Bingbing , Niu Bowen , Yang Guangmin , Wei Zhijie
Published: August 2022

A new photocatalyst, Er2FeSbO7, was prepared by solid phase sintering using the high-temperature synthesis method for the first time in this paper. Er2FeSbO7/BiTiSbO6 heterojunction (EBH) catalyst was prepared by the solvent thermal method for the first time. Er2FeSbO7 compound crystallized in the pyrochlore-type architecture and cubelike crystal system; the interspace group of Er2FeSbO7 was Fd3m and the crystal cellular parameter a of Er2FeSbO7 was 10.179902 Å. The band gap (BDG) width of Er2FeSbO7 was 1.88 eV. After visible light irradiation of 150 minutes (VLGI-150min) with EBH as a photocatalyst, the removal rate (RR) of enrofloxacin (ENR) concentration was 99.16%, and the total organic carbon (TOC) concentration RR was 94.96%. The power mechanics invariable k toward ENR consistency and visible light irradiation (VLGI) time with EBH as a photocatalyzer attained 0.02296 min−1. The power mechanics invariable k which was involved with TOC attained 0.01535 min−1. The experimental results showed that the photocatalytic degradation (PCD) of ENR within pharmaceutical waste water with EBH as a photocatalyzer under VLGI was in keeping with the single-order reactivity power mechanics. The RR of ENR with EBH as a photocatalyzer was 1.151 times, 1.269 times or 2.524 times that with Er2FeSbO7 as a photocatalyst, BiTiSbO6 as a photocatalyst, or N-doping TiO2 (N-TO) as a photocatalyst after VLGI-150min. The photocatalytic activity, which ranged from high to low among above four photocatalysts, was as follows: EBHP > Er2FeSbO7 > BiTiSbO6 > N-TO. After VLGI-150min toward three periods of the project with EBH as a photocatalyst, the RR of ENR attained 98.00%, 96.76% and 95.60%. The results showed that the stability of EBH was very high. With appending trapping agent, it could be proved that the oxidative capability for degrading ENR, which ranged from strong to weak among three oxidic radicals, was as follows: superoxide anion > hydroxyl radicals (HRS) > holes. This work provides a scientific basis for the research and oriented leader development of efficient heterojunction catalysts.
Characterization Studies on Graphene-Aluminium Nano Composites for Aerospace Launch Vehicle External Fuel Tank Structural Application
Authors: Jayaseelan Joel , Pazhani Ashwath , Michael Anthony Xavior , Paulchamy Jeyapandiarajan , Batako Andre , Hosamane Guruswamy Prashantha Kumar
Published: August 2022

From the aspect of exploring the alternative lightweight composite material for the aerospace launch vehicle external fuel tank structural components, the current research work studies three different grades of Aluminium alloy reinforced with varying graphene weight percentages that are processed through powder metallurgy (P/M) route. The prepared green compacts composite ingots are subjected to microwave processing (Sintering), hot extruded, and solution treated (T6). The developed Nano-graphene reinforced composite is studied further for the strength–microstructural integrity. The nature of the graphene reinforcement and its chemical existence within the composite is further studied, and it is found that hot extruded solution treated (HEST) composite exhibited low levels of carbide (Al4C3) formations, as composites processed by microwaves. Further, the samples of different grades reinforced with varying graphene percentages are subjected to mechanical characterisation tests such as the tensile test and hardness. It is found that 2 wt% graphene reinforced composites exhibited enhanced yield strength and ultimate tensile strength. Microstructural studies and fracture morphology are studied, and it is proven that composite processed via the microwave method has exhibited good ductile behaviour and promising failure mechanisms at higher load levels.
Mechanical Properties of Lightweight Foamed Concrete Modified with Magnetite (Fe3O4) Nanoparticles
Authors: Othuman Mydin Md Azree , Mohd Nawi Mohd Nasrun , Mohamed Othman , Sari Marti Widya
Published: August 2022

The advancement in sustainable construction has stimulated wide-ranging investigation of construction materials and practices globally. With exceptional thermal properties, fire resistance performance, excellent strength, and outstanding durability, concrete is the utmost extensively utilized construction material around the world. Taking into consideration the quantity of concrete necessary for numerous constructions works, improving concrete sustainability would be an extremely attractive potential. Lightweight foamed concrete (LFC) is tremendously permeable, and its mechanical properties weaken with a growth in the volume of voids. Air-void segregation from solid cement phases by means of aging, drainage, and merging of voids can trigger and reduce the stability and consistency of the emitted pores, making the LFC less reliable for main utilization in load-bearing components and structural elements. In turn, to augment LFC mechanical properties, the LFC cementitious matrix can be adjusted by adding various nanoparticles. The influence of magnetite nanoparticles (MNP) in LFC was not examined in the past; hence, there is some vagueness considering the mechanism to which level the MNP can affect the LFC mechanical properties. Thus, the aim of this study is to investigate the influences of MNP on the compressive, splitting tensile, and flexural LFC of 1000 kg/m3 density. Six MNP weight fractions of 0.10%, 0.15%, 0.20%, 0.25%, 0.30%, and 0.35% were considered. The parameters accessed were compressive, splitting tensile and flexural strengths. The correlation between strength parameters was established as well. The results indicated that a 0.25% weight fraction of MNP gave the best performance in terms of compressive, flexural, and splitting tensile strengths. The presence of MNP in the LFC matrix enhances the viscosity and yield stress of the mixture as well as an augmented utilization of LFC cementitious binder content, which can sustain the integrity of the wet networks hence preventing further amalgamation and aging of the voids.
A Composite Fabric with Dual Functions for High-Performance Water Purification
Authors: Tian Yankuan , Yang Xin , Xu Long , Wang Xueli , Yu Jianyong , Wu Dequn , Li Faxue , Gao Tingting
Published: August 2022

The dilemma of diminishing freshwater resources caused by water pollution has always impacted human life. Solar-driven interfacial evaporation technology has the potential for freshwater production via solar-driven distillation. However, in solar-driven interfacial evaporation technology, it is difficult to overcome the problem of wastewater containing various contaminants. In this work, we propose a bifunctional fabric created by depositing titanium dioxide@carbon black nanoparticles onto cotton fabric (TiO2@CB/CF). The TiO2@CB/CF has a coupling effect that includes the photothermal effect of CB and photocatalysis of TiO2, and it can not only generate clean water but can also purify contaminated water. The resulting bifunctional fabric can achieve an outstanding water evaporation rate of 1.42 kg m−2 h−1 and a conversion efficiency of 90.4% in methylene blue (MB) solution under one-sun irradiation. Simultaneously, the TiO2@CB/CF demonstrates a high photocatalytic degradation of 57% for MB solution after 2 h with light irradiation. It still shows a good photocatalysis effect, even when reused in an MB solution for eight cycles. Furthermore, the TiO2@CB/CF delivers excellent performance for actual industrial textile dyeing wastewater. This bifunctional fabric has a good application prospect and will provide a novel way to resolve the issue of freshwater scarcity.
Fractal Characteristic-Induced Optimization of the Fixed Abrasive Lapping Plate in Fabricating Bipolar Plate of Proton-Exchange Membrane Fuel Cells
Authors: Pan Guoqing , Wang Zhengwei , Wen Donghui
Published: August 2022

Purpose: A bipolar plate with fractal-characterized microstructures can realize intelligent energy transmission and obtain a high efficiency of proton-exchange membrane fuel cells. In this paper, fixed abrasive lapping technology is proposed to fabricate a surface microstructure on a bipolar plate with fractal characteristics. Methodology: The kinematics of the fixed abrasive lapping process was developed and employed to numerically investigate the particle trajectories moving on the target surface by considering the different arraying forms of diamonds on the lapping plate. Findings: It was found from an analysis of both the uniformity and the fractal characteristics that the arraying form of diamonds on the lapping plate, with the distribution of latitude and longitude with an angle of 30° and a gap of concentric circles of 40 mm with a minimum radius of 70 mm and maximum radius of 190 mm, can be used to obtain the best uniformity and fractal characteristics in the fixed abrasive lapping of a bipolar plate. Conclusions: The distribution of the latitude and longitude of 40° and 30° considered in this study is expected to realize the best machining performance in the bipolar plate and present good cell performance.
Micro Non-Destructive Testing and Evaluation
Authors: Bruno Giovanni
Published: August 2022

What is meant by ‘Micro Non-Destructive Testing and Evaluation’ [...]
Irradiation-Induced Amorphous-to-Crystalline Phase Transformations in Ceramic Materials
Authors: Koroni Cyrus , Olsen Tristan , Wharry Janelle P. , Xiong Hui
Published: August 2022

Amorphous ceramics are a unique class of materials with unusual properties and functionalities. While these materials are known to crystallize when subjected to thermal annealing, they have sometimes been observed to crystallize athermally when exposed to extreme irradiation environments. Because irradiation is almost universally understood to introduce disorder into materials, these observations of irradiation-induced ordering or crystallization are unusual and may partially explain the limited research into this phenomenon. However, the archival literature presents a growing body of evidence of these irradiation-induced amorphous-to-crystalline (a-to-c) phase transformations in ceramics. In this perspective, the summary and review of examples from the literature of irradiation-induced a-to-c transformations for various classifications of ceramics are provided. This work will highlight irradiation conditions and material parameters that appear most influential for activating a-to-c transformations, identify trends, examine possible mechanisms, and discuss the impact of a-to-c transformations on material properties. Finally, future research directions that will enable researchers to harness a-to-c transformations to tailor materials behaviors will be provided.
An Environmentally Friendly Inverse Microemulsion Method to Synthesize Polyacrylamide
Authors: Guo Qing , Yin Longlong , Wang Xiao , Yuan Jing , Zhang Qianfeng
Published: August 2022

Polyacrylamide (PAM) was prepared by a new method of inverse microemulsion polymerization, with (NH4)2S2O8-Na2SO3 as initiator and liquid paraffin/Span80-Op10/AM-H2O-NaAc as polymerization system in this paper. The effects of initiator dosage, emulsifier dosage, monomer concentration, oil–water ratio, and temperature on molecular weight, electrical conductivity, particle size distribution, and monomer conversion were studied as well. The results indicate that that the more stable Polyacrylamide (PAM) polymer was prepared under the conditions of initiator dosage of 0.4~0.5%, emulsifier dosage of 55~60%, temperature of 40~45 °C, hydrophile–lipophile balance (HLB) value of 8.0~8.2, and NaAc concentration of 3%.
One-Stage Hydrothermal Growth and Characterization of Epitaxial LaMnO3 Films on SrTiO3 Substrate
Authors: Guo Keyu , Tao Yaqiu , Liu Yunfei , Lyu Yinong , Pan Zhigang
Published: August 2022

Epitaxial LaMnO3 thin films were grown on SrTiO3 substrate using a one-stage hydrothermal route from La(NO3)3, MnCl2 and KMnO4 in an aqueous solution of 10 M KOH at 340 °C. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) indicate full coverage of LaMnO3 on the substrate. X-ray diffraction in the symmetric ω/2θ mode suggests the film has an out-of-plane preferred orientation along the [001] direction of the substrate. The LaMnO3 epitaxial thin film growth mechanism is proposed based on the analysis of the atomic sharp interface formed between LaMnO3 and the SrTiO3 substrate, as seen by aberration−corrected scanning transmission electron microscopy (AC−STEM) imaging in combination with electronic energy loss spectroscopy (EELS). Compared with the conventional vapor deposition methods, the one-stage hydrothermal route opens up a new way to fabricate complex oxide epitaxial heterostructures.
Separate Calibration of Johnson–Cook Model for Static and Dynamic Compression of a DNAN-Based Melt-Cast Explosive
Authors: Xie Hanfei , Zhang Xiangrong , Miao Feichao , Jiang Tao , Zhu Yingzhong , Wu Xinxin , Zhou Lin
Published: August 2022

When describing the relation between the flow stress and plastic strain of a material under a wide range of strain rates and temperatures, the original Johnson–Cook model generally requires a complicated modification, resulting in a loss of simplicity and clear physical interpretation. In this paper, without modification, the original Johnson–Cook model was calibrated separately for the static and dynamic compression of a DNAN-based melt-cast explosive. The stress–strain curves for static and dynamic compression of this explosive were experimentally measured with a universal testing machine and a split-Hopkinson pressure bar, respectively. Based on the stress–strain curves, the flow stress vs. plastic strain data were extracted and used to calibrate the Johnson–Cook model. The calibration process is described. The parameters for the strain term, strain rate term, and temperature term were fitted sequentially. One set of model parameters was not able to fully describe the relationship between flow stress and plastic strain for both the static and dynamic compression of the DNAN-based melt-cast explosive. Two sets of model parameters were separately calibrated and compared for the static and dynamic compression of this explosive. The effects of the adiabatic temperature rise and the definition of the yield point on this calibration were also investigated.
Magnetic Interactions in Wiegand Wires Evaluated by First-Order Reversal Curves
Authors: Sha Guorong , Yang Chao , Song Zenglu , Takemura Yasushi
Published: August 2022

Wiegand wires exhibit a unique fast magnetization reversal feature in the soft layer that is accompanied by a large Barkhausen jump, which is also known as the Wiegand effect. However, the magnetic structure and interaction in Wiegand wires cannot be evaluated by conventional magnetization hysteresis curves. We analyzed the magnetic properties of Wiegand wires at various lengths by measuring the first-order reversal curves (FORCs) and by evaluating the FORC diagram from a series of FORCs. In particular, we used a FeCoV Wiegand wire with a magnetic soft outer layer, an intermediate layer, and a hard core. The magnetization of the various layers in the wire could be identified from the FORC diagrams. Furthermore, based on the interaction between multiple layers, the positive and negative polarity of the FORC distribution was clarified.
Preparation of Copper-Decorated Activated Carbon Derived from Platamus occidentalis Tree Fiber for Antimicrobial Applications
Authors: Mahlangu Thembisile , Arunachellan Iviwe , Sinha Ray Suprakas , Onyango Maurice , Maity Arjun
Published: August 2022

This study focuses on a greener approach to synthesizing activated carbon by carbonizing Platamus occidentalis tree fibers (TFSA) with 98% H2SO4 at 100 °C. The resulted TFSA was employed as an effective adsorbent for copper ions in aqueous media, yielding copper decorated TFSA (Cu@TFSA). The successful adsorption of copper onto the TFSA was proven through extensive characterization techniques. Herein, the TEM and XPS showed that copper nanoparticles were formed in situ on the TFSA surface, without the use of additional reducing and stabilizing agents nor thermal treatment. The surface areas of TFSA and Cu@TFSA were 0.0150 m2/g and 0.3109 m2/g, respectively. Applying the Cu@TFSA as an antimicrobial agent against Escherica coli ( E. coli) and Salmonella resulted in the potential mitigation of complex secondary pollutants from water and wastewater. The Cu@TFSA exhibited outstanding antimicrobial activity against E. coli and Salmonella in both synthetic and raw water samples. This demonstrated a complete growth inhibition observed within 120 min of exposure. The bacteria inactivation took place through the destruction of the bacteria cell wall and was confirmed by the AFM analysis technique. Cu@TFSA has the potential to be used in the water and wastewater treatment sector as antimicrobial agents.
Development of a High Strength Geopolymer Incorporating Quarry Waste Diabase Mud (DM) and Ground Granulated Blast-Furnace Slag (GGBS)
Authors: Polydorou Thomaida , Spanou Maria , Savva Pericles , Sakkas Konstantinos , Oikonomopoulou Konstantina , Petrou Michael F. , Nicolaides Demetris
Published: August 2022

This study presents the development and experimental assessment of novel, high strength, cementless binders that incorporate alkali-activated local waste. A silica-rich diabase mud (DM), currently considered as waste, was previously investigated for geopolymerization, signifying that the DM lacked the necessary reactivity to provide a stable geopolymer binder alone. Moreover, even after incorporation of small amounts of cement and metakaolin, the DM mixtures still did not yield adequate mechanical properties. In this study, the local DM was instead combined with another industrial byproduct known as Ground Granulated Blast-furnace Slag (GGBS) in varying mixtures. The mixture design trials enabled the development of three high strength cementless geopolymer mixtures with 28-day compressive strengths ranging between 60 and 100 MPa, comparable to conventional concrete compressive strengths. The results indicate that the innovative geopolymer material is very promising for the manufacturing of pavement tiles and other precast construction products. Most importantly, this study presents the first successful development of a construction material of adequate compressive strength that can absorb large quantities of the abundant quarry waste, following a course of 10 years of unsuccessful attempts to valorize the local DM. Although difficulties were encountered due to a high reactivity rate, especially for the mix that included the highest GGBS content, prototype pavement tiles were manufactured and assessed experimentally. The results reveal a promising potential of valorizing the local DM in the development of precast geopolymer products, despite the effects of shrinkage cracking on the experimental evaluation of the material mechanical properties.
Milling of Three Types of Thin-Walled Elements Made of Polymer Composite and Titanium and Aluminum Alloys Used in the Aviation Industry
Authors: Ciecieląg Krzysztof , Zaleski Kazimierz
Published: August 2022

The machining of thin-walled elements used in the aviation industry causes may problems, which create a need for studying ways in which undesirable phenomena can be prevented. This paper presents the results of a study investigating face milling thin-walled elements made of titanium alloy, aluminum alloy and polymer composite. These materials were milled with folding double-edge cutters with diamond inserts. The results of maximum vertical forces and surface roughness obtained after machining elements of different thicknesses and unsupported element lengths are presented. The results of deformation of milled elements are also presented. The results are then analyzed by ANOVA. It is shown that the maximum vertical forces decrease (in range 42–60%) while the ratio of vertical force amplitude to its average value increases (in range 55–65%) with decreasing element thickness and increasing unsupported element length. It is also demonstrated that surface roughness deteriorates (in range 100% for aluminum, 30% titanium alloy, 15% for CFRP) with small element thicknesses and long unsupported element lengths. Long unsupported element lengths also negatively (increasing deformation several times) affect the accuracy of machined elements.
Evaluation of the Performance of Atomic Diffusion Additive Manufacturing Electrodes in Electrical Discharge Machining
Authors: Bordón Pablo , Paz Rubén , Monzón Mario D.
Published: August 2022

Atomic Diffusion Additive Manufacturing (ADAM) is an innovative Additive Manufacturing process that allows the manufacture of complex parts in metallic material, such as copper among others, which provides new opportunities in Rapid Tooling. This work presents the development of a copper electrode manufactured with ADAM technology for Electrical Discharge Machining (EDM) and its performance compared to a conventional electrolytic copper. Density, electrical conductivity and energy-dispersive X-ray spectroscopy were performed for an initial analysis of both ADAM and electrolytic electrodes. Previously designed EDM experiments and optimizations using genetic algorithms were carried out to establish a comparative framework for both electrodes. Subsequently, the final EDM tests were carried out to evaluate the electrode wear rate, the roughness of the workpiece and the rate of material removal for both electrodes. The EDM results show that ADAM technology enables the manufacturing of functional EDM electrodes with similar material removal rates and rough workpiece finishes to conventional electrodes, but with greater electrode wear, mainly due to internal porosity, voids and other defects observed with field emission scanning electron microscopy.
Experimental Research of the Hydrodynamic Processes of an Axial Piston Water Hydraulic Pump
Authors: Todić Nenad , Savić Slobodan , Gordić Dušan , Petrović Radovan
Published: August 2022

Water hydraulic components and systems play pivotal roles in the development of modern hydraulics. Sustainable development and environmental protection cannot be imagined without the use of water as a working medium in modern hydraulic systems. An axial piston pump is the main component of these systems. This paper presents analytical and experimental methods for the development of an axial piston pump. The presented mathematical model is rooted in numerous research results in the literature and in our own experience. It is based on mathematical modelling of hydrodynamic processes of a water hydraulic axial piston pump which, combined with experimental research, provides a great tool to analyse the influence of different factors on the operating process and to optimise the pump parameters. The experimental equipment used in our tests simulates a real hydraulic installation, and the obtained results are very close to the actual operating parameters. This research included a modification of the swash plate in order to achieve ideal operating parameters and, thus, extend the service life of the pump. Water has a number of advantages over conventional hydraulic oils. It is a sustainable, environmentally friendly resource, more readily available than oil (lower transportation costs), cheaper to dispose of, non-flammable and non-toxic, and its high thermal conductivity aids in cooling.
Auto-Encoder-Enabled Anomaly Detection in Acceleration Data: Use Case Study in Container Handling Operations
Authors: Jakovlev Sergej , Voznak Miroslav
Published: August 2022

The sudden increase in containerization volumes around the globe has increased the overall number of cargo losses, infrastructure damage, and human errors. Most critical losses occur during handling procedures performed by port cranes while sliding the containers to the inner bays of the ship along the vertical cell guides, damaging the main metal frames and causing the structure to deform and lose its integrity and stability. Strong physical impacts may occur at any given moment, thus in-time information is critical to ensure the clarity of the processes without halting operations. This problem has not been addressed fully in the recent literature, either by researchers of the engineering community or by the logistics companies’ representatives. In this paper, we have analyzed the conventional means used to detect these critical impacts and found that they are outdated, having no real-time assessment capability, only post-factum visual evaluation results. More reliable and in-time information could benefit many actors in the transportation chain, making transportation processes more efficient, safer, and reliable. The proposed solution incorporates the monitoring hardware unit and the analytics mechanism, namely the auto-encoder technology, that uses the acceleration parameter to identify sensor data anomalies and informs the end-user if these critical impacts occurred during handling procedures. The proposed auto-encoder analytical method is compared with the impacts detection methodology (IDM), and the result indicates that the proposed solution is well capable of detecting critical events by analyzing the curves of reshaped signals, detecting the same impacts as the IDM, while improving the speed of the short-term detection periods. We managed to detect–predict between 9 and 18 impacts, depending on the axis of container sway. An experimental study suggests that if programmed correctly, the auto-encoder (AE) can be used to detect deviations in time-series events in different container handling scenarios.
Research on Fault Diagnosis of Six-Phase Propulsion Motor Drive Inverter for Marine Electric Propulsion System Based on Res-BiLSTM
Authors: Xie Jialing , Shi Weifeng , Shi Yuqi
Published: August 2022

To ensure the implementation of the marine electric propulsion self-healing strategy after faults, it is necessary to diagnose and accurately classify the faults. Considering the characteristics of the residual network (ResNet) and bidirectional long short-term memory (BiLSTM), the Res-BiLSTM deep learning algorithm is used to establish a fault diagnosis model to distinguish the types of electric drive faults. First, the powerful fault feature extraction ability of the residual network is used to deeply mine the fault features in the signals. Then, perform time-series learning through a bidirectional long short-term memory network, and further excavate the transient time-series features in the fault features so as to achieve the accurate classification of drive inverter faults. The effectiveness of the method is verified using noise-free fault data, and the robustness of the method is verified using data with varying degrees of noise. The results show that compared with conventional deep learning algorithms, Res-BiLSTM has the fastest and most stable training process, the diagnostic performance is improved, and the accuracy can be maintained over 95% under 25–19 dB. It has certain robustness and can be applied to marine electric propulsion systems drive inverter fault diagnosis, and its results can provide data support for the implementation of self-healing control strategies.
Power Loss Analysis of a Five-Phase Drive System Using a Synchronous Reluctance Motor and an Indirect Matrix Converter with Reduced Switching Losses
Authors: Tawfiq Kotb B. , Ibrahim Mohamed N. , Sergeant Peter
Published: August 2022

This paper introduces and analyzes the power losses of a five-phase drive system based on an indirect matrix converter (IMC) and a five-phase synchronous reluctance motor (SynRM). The different loss components in the power converter and the motor have been discussed and analyzed. Moreover, a control strategy is applied to decrease the power converter losses and make the system superior to the conventional one. The carrier-based pulse-width-modulation (CBPWM) method is used for this. Through the CBPWM, switching losses are kept as low as possible in this technique by ensuring that the rectifier stage experiences zero current commutation. To achieve this, the rectifier and inverter stages are synchronized so that the commutation in the rectifier stage occurs at the zero vectors of the inverter, which corresponds to a zero DC-link current. The converter will therefore have less switching losses thanks to the rectifier’s null value. Experimental validation has shown the usefulness of the proposed CBPWM in providing lower switching losses in the IMC. Additionally, a comparison of the proposed drive system’s performance with a traditional three-phase SynRM-based inverter will be carried out in the speed and torque control modes.
Dynamic Modeling of a Hydraulic Excavator Stick by Introducing Multi-Case Synthesized Load Spectrum for Bench Fatigue Test
Authors: Wang Penghui , Xiang Qingyi , Królczyk Grzegorz , Lu Pengmin , Wang Binhua , Li Zhixiong
Published: August 2022

A multi-case load spectrum compiling method is proposed in this study for dynamic modeling of a hydraulic excavator stick to simplify and accelerate the fatigue bench test. This new method includes a simplified criterion of small-load-omitting threshold based on the principle of invariable fatigue damage, an extreme value inference criterion based on the overflow characteristics of the hydraulic system, and a synthetic extrapolation method under various working conditions. Firstly, a one-dimensional spectrum of a medium-sized excavator stick was compiled. Then, the program load spectrum for the bench fatigue test was obtained by modifying the one-dimensional spectrum based on the damage consistency criterion and the damage equivalent principle. Lastly, the fatigue tests were conducted using the program load spectrum, as well as using the random spectrum. The comparison results demonstrate that the damage location and fatigue life distribution of the stick using these two spectra are generally consistent, with a relative error smaller than 8.8%; however, the proposed program load spectrum can accelerate the test process with less time consuming than that of the random spectrum. As a result, the multi-case load spectrum is feasible and reliable for dynamic modeling of the hydraulic excavator stick in practice.
Full Duplex Relaying with Intelligent Reflecting Surface: Joint Beamforming and Phase Adjustment
Authors: Hwang Duckdong , Yang Janghoon , Nam Sung-Sik , Song Hyoung-Kyu
Published: August 2022

In this paper, an optimization algorithm is proposed for the system, where a decode-and-forward (DaF) protocol based full duplex relay (FDR) and an intelligent reflecting surface (IRS) work together to deliver message signals from a source to a destination. The transmission is carried out in a single time frame due to the full duplex nature of the FDR and IRS. The joint optimization of the beamformers for the multiple antenna sets at the source along with the FDR antenna sets and the phase adjustment of the reflecting elements at the IRS is proposed. Though separate optimizations of the beamformers and the phase adjustment were available previously, the joint one is more challenging due to the increased number of signal paths and the impacts from these new paths. To accommodate conflicting requirements from different paths, the reflecting elements of the IRS are cleverly grouped into the corresponding number of sets, where the requirements are met separately through the optimizations of the phase values of the corresponding group. For the beamformer optimization, we parameterize the beamforming vectors, which results in two concave optimization problems for the source and for the FDR relay. These optimization sets are implemented in an alternating manner to reach a reasonable solution. Simulation results are provided to illustrate the impacts of the proposed algorithm in various implementation scenarios and parameter sets. These results identify the gains the proposed algorithm provides and the scenarios where these gains are expected.
Remarks on Sugeno Integrals on Bounded Lattices
Authors: Halaš Radomír , Pócs Jozef , Pócsová Jana
Published: August 2022

A discrete Sugeno integral on a bounded distributive lattice L is defined as an idempotent weighted lattice polynomial. Another possibility for axiomatization of Sugeno integrals is to consider compatible aggregation functions, uniquely extending the L-valued fuzzy measures. This paper aims to study the mentioned unique extension property concerning the possible extension of a Sugeno integral to non-distributive lattices. We show that this property is equivalent to the distributivity of the underlying bounded lattice. As a byproduct, an alternative proof of Iseki’s result, stating that a lattice having prime ideal separation property for every pair of distinct elements is distributive, is provided.
Lateral Dynamic Simulation of a Bus under Variable Conditions of Camber and Curvature Radius
Authors: Olmeda Ester , Carrillo Li Enrique Roberto , Rodríguez Hernández Jorge , Díaz Vicente
Published: August 2022

The objective of this paper is to describe a model for the simulation of the lateral dynamics of a vehicle, specifically buses, under variable trajectory conditions, such as camber and radius of curvature; in addition, a variable speed is added as a simulation parameter. The objective of this study is the prevention of vehicle rollover and sideslip. An 8 degrees of freedom model was developed, considering a front and a rear section of the bus with its respective suspension system, and both sections have been connected by a torsion spring that emulates the torsional stiffness of the vehicle chassis. A Panhard bar is also added at the rear as an additional element to the suspension and the behavior of the bus when it is added is analyzed. This model also allows the evaluation of the force on each suspension component, which allows for future controllability of the active suspension components. The results show the dynamic behavior of the vehicle, and some indicators are introduced to show the possible sideslip or rollover. As a conclusion, the influence of the road parameters on the dynamic behavior of the bus and the effect of the Panhard bar on the dynamic behavior of the bus can be pointed out.
Mathematical Modeling and Stability Analysis of a Delayed Carbon Absorption-Emission Model Associated with China’s Adjustment of Industrial Structure
Authors: Han Leilei , Sui Haokun , Ding Yuting
Published: August 2022

Global warming has brought about enormous damage, therefore, some scholars have begun to conduct in-depth research on peak carbon dioxide emissions and carbon neutrality. In this paper, based on the background of China’s upgrading industrial structure and energy structure, we establish a delayed two-dimensional differential equation model associated with China’s adjustment of industrial structure. Firstly, we analyze the existence of the equilibrium for the model. We also analyze the characteristic roots of the characteristic equation at each equilibrium point for the model, then, we analyze the stability of the equilibrium point for the model according to the characteristic root, and discuss the existence of Hopf bifurcation of the system by using bifurcation theory. Secondly, we derive the normal form of Hopf bifurcation by using the multiple time scales method. Then, through the official real data, we present the range of some parameters in the model, and determine a set of parameters by reasonable analysis. The validity of the theoretical results is verified by numerical simulations. Finally, we use the real data to forecast the time of peak carbon dioxide emissions and carbon neutralization. Eventually, we put forward some suggestions based on the current situation of carbon emission and absorption in China, such as planting trees to increase the growth rate of carbon absorption, deepening industrial reform and optimizing energy structure to reduce carbon emissions.
Fixed-Time Convergent Gradient Neural Network for Solving Online Sylvester Equation
Authors: Tan Zhiguo
Published: August 2022

This paper aims at finding a fixed-time solution to the Sylvester equation by using a gradient neural network (GNN). To reach this goal, a modified sign-bi-power (msbp) function is presented and applied on a linear GNN as an activation function. Accordingly, a fixed-time convergent GNN (FTC-GNN) model is developed for solving the Sylvester equation. The upper bound of the convergence time of such an FTC-GNN model can be predetermined if parameters are given regardless of the initial conditions. This point is corroborated by a detailed theoretical analysis. In addition, the convergence time is also estimated utilizing the Lyapunov stability theory. Two examples are then simulated to demonstrate the validation of the theoretical analysis, as well as the superior convergence performance of the presented FTC-GNN model as compared to the existing GNN models.
Deep Learning-Based Plant-Image Classification Using a Small Training Dataset
Authors: Batchuluun Ganbayar , Nam Se Hyun , Park Kang Ryoung
Published: August 2022

Extensive research has been conducted on image augmentation, segmentation, detection, and classification based on plant images. Specifically, previous studies on plant image classification have used various plant datasets (fruits, vegetables, flowers, trees, etc., and their leaves). However, existing plant-based image datasets are generally small. Furthermore, there are limitations in the construction of large-scale datasets. Consequently, previous research on plant classification using small training datasets encountered difficulties in achieving high accuracy. However, research on plant image classification based on small training datasets is insufficient. Accordingly, this study performed classification by reducing the number of training images of plant-image datasets by 70%, 50%, 30%, and 10%, respectively. Then, the number of images was increased back through augmentation methods for training. This ultimately improved the plant-image classification performance. Based on the respective preliminary experimental results, this study proposed a plant-image classification convolutional neural network (PI-CNN) based on plant image augmentation using a plant-image generative adversarial network (PI-GAN). Our proposed method showed the higher classification accuracies compared to the state-of-the-art methods when the experiments were conducted using four open datasets of PlantVillage, PlantDoc, Fruits-360, and Plants.
Variable Selection for Spatial Logistic Autoregressive Models
Authors: Liang Jiaxuan , Cheng Yi , Su Yuqi , Xiao Shuyue , Song Yunquan
Published: August 2022

When the spatial response variables are discrete, the spatial logistic autoregressive model adds an additional network structure to the ordinary logistic regression model to improve the classification accuracy. With the emergence of high-dimensional data in various fields, sparse spatial logistic regression models have attracted a great deal of interest from researchers. For the high-dimensional spatial logistic autoregressive model, in this paper, we propose a variable selection method with for the spatial logistic model. To identify important variables and make predictions, one efficient algorithm is employed to solve the penalized likelihood function. Simulations and a real example show that our methods perform well in a limited sample.
Polymer Electrolytes Based on Na-Nafion Plasticized by Binary Mixture of Ethylene Carbonate and Sulfolane
Authors: Krupina Anna A. , Kayumov Ruslan R. , Nechaev Grigory V. , Lapshin Alexander N. , Shmygleva Lyubov V.
Published: August 2022

The development of post-lithium current sources, such as sodium-ion batteries with improved energy characteristics and an increased level of safety, is one of the key issues of modern energy. It requires the search and study of materials (including electrolytes) for these devices. Polyelectrolytes with unipolar cationic conductivity based on Nafion® membranes are promising. In this work, the effect of swelling conditions of the Nafion® 115 membrane in Na+-form with mixtures of aprotic solvents such as ethylene carbonate and sulfolane on its physicochemical and electrotransport properties was studied. Nafion-Na+ membranes were swollen in a mixture of solvents at temperatures of 40, 60, and 80 °C. The results were obtained using methods of impedance spectroscopy, simultaneous thermal analysis, and IR spectroscopy. The best conductivity was observed for a membrane swelling at 80 °C in a mixture with a mass fraction of ethylene carbonate of 0.5, which reaches 10−4 S cm−1 at 30 °C and retains rather high values down to −60 °C (10−6 S cm−1). Thus, it is possible to expand the operating temperature range of a sodium battery by varying the composition of the polymer electrolyte and the conditions for its preparation.
Ignition and Combustion Characteristics of B/NC/CuO Thermite Microparticles
Authors: Wang Jie , Yang Hongtao , Cheng Long , Gao Pin , Li Yanchun , Song Dongming
Published: August 2022

To improve the combustion stability and ignition performance of thermite, B/NC/CuO micro particles were prepared from boron (B), nano copper oxide (CuO), and nitrocellulose (NC) as an energetic binder through the electrospray technique. The burning rate dependency on boron content, ambient temperature, and pressure was estimated by compressing B/NC/CuO micro particles into columns. Scanning electron microscopy results show that the sizes of these particles mostly lie in the range of 3–4 μm. The particles are ignitable and burn consistently with minor variations in the conditions: B content (8.3–17%), ambient temperature (−50–55 °C), and ambient pressure (0.02–0.1 MPa). The optimum formula was observed for micro particles with 11 wt% B content. Compared with the ball milling sample, the standard deviation of the burning rate of the electrosprayed sample was reduced by 32%. Combustion is barely affected by ambient pressure. Between −50 °C to 55 °C, the burning rate of B/NC/CuO increases by 14.16% from an initial rate of 13.35 mm⋅s−1. In addition, the laser ignition energy required for B/NC/CuO microparticles was also reduced from 70 to 45 mJ.
Metabolite Changes in Orange Dead Leaf Butterfly Kallima inachus during Ontogeny and Diapause
Authors: Li Ming-Jie , Jiang Guo-Fang , Wang Wei
Published: August 2022

Holometabolism is a form of insect development which includes four life stages: egg, larva, pupa, and imago (or adult). The developmental change of whole body in metabolite levels of holometabolous insects are usually ignored and lack study. Diapause is an alternative life-history strategy that can occur during the egg, larval, pupal, and adult stages in holometabolous insects. Kallima inachus (Lepidoptera: Nymphalidae) is a holometabolous and adult diapausing butterfly. This study was intended to analyze metabolic changes in K. inachus during ontogeny and diapause through a non-targeted UPLC-MS/MS (ultra-performance liquid chromatograph coupled with tandem mass spectrometry) based metabolomics analysis. A variety of glycerophospholipids (11), amino acid and its derivatives (16), and fatty acyls (nine) are crucial to the stage development of K. inachus. 2-Keto-6-acetamidocaproate, N-phenylacetylglycine, Cinnabarinic acid, 2-(Formylamino) benzoic acid, L-histidine, L-glutamate, and L-glutamine play a potentially important role in transition of successive stages (larva to pupa and pupa to adult). We observed adjustments associated with active metabolism, including an accumulation of glycerophospholipids and carbohydrates and a degradation of lipids, as well as amino acid and its derivatives shifts, suggesting significantly changed in energy utilization and management when entering into adult diapause. Alpha-linolenic acid metabolism and ferroptosis were first found to be associated with diapause in adults through pathway analyses. Our study lays the foundation for a systematic study of the developmental mechanism of holometabolous insects and metabolic basis of adult diapause in butterflies.