bluuebunny/crossref_metadata_2025 huggingface dataset:
Patterning of Surfaces for Subsequent Roll Bonding in a Low-Oxygen Environment Using Deformable Mesh Inlays
Authors: Frolov Yaroslav , Bobukh Oleksandr , Samsonenko Andrii , Nürnberger Florian
Published: September 2023

Efficient roll bonding for the manufacturing of clad strips not only requires surface activation but also is improved by a surface patterning to reduce the initial contact area. This increases contact stresses and facilitates a joining without an increasing rolling force. Experiments to pattern surfaces with deformable inlays during cold rolling for a subsequent bonding in low-oxygen atmosphere were carried out using two types of rolling mills, two types of inlays and two types of assemblies. Digital twins of selected experiments were created by means of the FE simulation software QForm UK 10.2.4. The main set of rolling parameters, which play a significant role during formation of the pattern shape considering deformation of the patterning tool, were investigated. The pilot roll bonding of patterned components under vacuum conditions, provided using vacuum sealer bags, allowed for an experimental realization of this approach. The concept technological chain of roll bonding in a low-oxygen or oxygen-free environment comprises the following stages: roll patterning; surface activation and sealing of the strips in a vacuum bag; subsequent roll bonding of the prepared strips inside the protective bag. The difference between the shape of the pattern created and the initial shape of the mesh insert can be quantitatively described by the change of its angle. This difference reaches maximum values when smaller rolls are used with increased rolling reductions. This maximum value is limited by the springback of the deformed insert; the limit is reached more easily if the inlay is not positioned on the rolling plane.
Development of a Simplified Performance Monitoring System for Small and Medium Sized Ships
Authors: Kim Seongwan , Kim Heemoon , Jeon Hyeonmin
Published: September 2023

Regulations on emissions from ships are being strengthened, and emission reduction systems and alternative technologies are being developed. In addition, the amount of emissions is closely related to the performance of the propulsion systems of the ship; however, performance measurement systems have mainly been developed for large commercial ships. For small and medium-sized ships, although the output of the propulsion system is rather low, the number of vessels sailing in the coast is very high. Therefore, a performance-monitoring system is required for small and medium-sized ships. However, for small and medium-sized ships, there are no suitable performance and emissions calculation systems. Conventional performance-measuring and analysis systems for large ships have difficulties in terms of their cost and installation when applied to small and medium-sized ships. In this study, a new system was developed that is able to calculate the speed, power, fuel consumption, carbon dioxide emission assumptions, and efficiency of a ship by receiving simple key data such as GPS, fuel flow, and rpm data rather than checking the ship’s condition using massive forms of data. The system transmits data to the shore’s remote-monitoring center in real-time through a communication network. Using these data, it is possible to estimate a ship’s aging factor, engine performance, amount of exhaust gas, etc., and the accumulated data of all coastal ships in a country can be used as basic data for governments to use to support eco-friendly ship policies.
Modal Analysis of the Hydrodynamic Force of a Capsule in a Hydraulic Capsule Pipeline
Authors: Zhao Yiming , Li Yongye , Sun Xihuan
Published: September 2023

Hydrodynamic forces influence the efficiency and safety of pipeline transport in ocean engineering. A capsule pipeline is an example of pipeline transportation. In this work, a dynamic model is proposed to explain the oscillating motion of a capsule in a hydraulic capsule pipeline (HCP). The main study was conducted using a modal analysis of hydrodynamic forces acting on a capsule, which could be divided into frictional drag and pressure drag forces. The results indicated the presence of independent modes with different contributions to the hydrodynamic forces. Ultimately, the first to fiftieth modes represented 94~97.3% of the hydrodynamic force contributions. These modes had their own frequency ranges and power spectrum density (PSD) functions, and the frictional drag and pressure drag were both found to coincide with the narrow-band characteristics of the lower-order modes. However, the PSD functions of the frictional drag were found to fulfill the wide-band characteristics corresponding to the higher-order modes. Then, coherent structures were extracted. As the mode order increased, the vortices became more fragile and the frequency became higher. This phenomenon coincided with an increase in the frequency of the time coefficient peak, which became larger. This work could provide new perspectives on the hydrodynamic forces of pipeline transport, especially its dynamic analysis of the interaction between a rigid capsule and fluid flow.
Underwater Geomagnetic Localization Based on Adaptive Fission Particle-Matching Technology
Authors: Yu Huapeng , Li Ziyuan , Yang Wentie , Shen Tongsheng , Liang Dalei , He Qinyuan
Published: September 2023

The geomagnetic field constitutes a massive fingerprint database, and its unique structure provides potential position correction information. In recent years, particle filter technology has received more attention in the context of robot navigation. However, particle degradation and impoverishment have constrained navigation systems’ performance. This paper transforms particle filtering into a particle-matching positioning problem and proposes a geomagnetic localization method based on an adaptive fission particle filter. This method employs particle-filtering technology to construct a geomagnetic matching positioning model. Through adaptive particle fission and sampling, the problem of particle degradation and impoverishment in traditional particle filtering is solved, resulting in improved geomagnetic matching positioning accuracy. Finally, the proposed method was tested in a sea trial, and the results show that the proposed method has a lower positioning error than traditional particle-filtering and intelligent particle-filtering algorithms. Under geomagnetic map conditions, an average positioning accuracy of about 546.44 m is achieved.
An Innovative Designed Velocimeter Application for Set Net Fishery
Authors: Chiu Cheng-Chang , Liao Teh-Lu , Chen Chiung-Hsing , Li Hsiang
Published: September 2023

This article is aimed at the problems encountered by the fishing ground of set nets in Taiwan when the set net operators need to work when the weather is bad at sea. We developed a velocimeter that can be placed in the ocean for a long time and change sensing directions with the flow direction. The self-designed velocimeter has advantages, such as simple operation, low cost, and easy maintenance. With wireless monitoring and an early warning system, it can monitor current velocity, flow direction, sea temperature, and displacement. The data is transmitted back to the operator through the radio transmission module as a basis for dispatching personnel to go out to sea for fishing. To prevent the set net from drifting into the open sea due to bad weather, a GPS module is used to monitor the current location of the set net. If the waves wash away the set net, the warning signal can be received the first time to prevent the floating set net from endangering the safety of ship navigation and the survival of marine life. This innovative technology aligns with SDG 14, which aims to “conserve and sustainably use the oceans, seas, and marine resources for sustainable development”.
The Dynamic Response of a Floating Wind Turbine under Collision Load Considering the Coupling of Wind-Wave-Mooring Loads
Authors: Zong Shuai , Liu Kun , Zhang Yichi , Yan Xingpeng , Wang Yukai
Published: September 2023

As the number of offshore wind turbines continues to rise and their proximity to navigational routes decreases, the risk of collisions between passing vessels and wind turbines increases, thereby presenting serious threats to the safety of personnel and equipment. Given that collisions between floating wind turbines and vessels entail a complex interplay of wind, wave, and mooring loads, this study established a bidirectional fluid-structure coupling simulation methodology based on Star-CCM+ and ABAQUS. Under the combined influences of wind, wave, and mooring loads, the study investigated the dynamic response of floating wind turbines following bow and side impacts from vessels. Analyses were conducted on the structural damage and deformation of floating wind turbines, the transformation of energy during collision processes, and the resultant motion response of the turbines. A sensitivity analysis was performed on parameters such as collision speed, collision angle, wind speed, and wave height. The findings indicate that the amplitude of pitching and heaving motions of the turbine exceed those observed under conditions devoid of collision loads, with the amplitude of motion intensifying with an increase in these parameters. The turbine’s floating body absorbed a minimal amount of internal energy, leading to minor damage, with the stress generated predominantly localized in the collision area of the floating body. The impact of a side collision from vessels exerted a larger influence on the structural dynamic response of floating wind turbines. The analysis results indicate that even though the offshore wind turbine structure is not critically damaged by ship impact, the equipment inside may still fail to work due to the high value of acceleration induced by ship impact. The research outcomes can benefit the safety design of offshore wind turbines in engineering practice.
Exploring the Relationship between Urban Park Greenery at Different Levels and Physical Activity: A Study Using the Hierarchical Linear Model
Authors: Tao Zheng , Guo Jiankang , Chen Junqi , Wu Wenrui , Chen Dan
Published: September 2023

Urban parks play a pivotal role in shaping physical activity (PA), yet our comprehension of the specific influence of park greenery remains limited. In this study, we focused on three Shanghai urban parks, conducting a comprehensive year-long on-site observation to delve into greenery’s impact on PA. By employing the hierarchical linear model analysis, we uncovered a robust correlation between internal and surrounding park greenery and PA density and diversity. Within a 400 m radius, indicators such as normalized difference vegetation index, green view ratio, Shannon’s diversity index, and color-leaf plant ratio demonstrated a negative relationship with PA density. Conversely, the green coverage ratio and green view ratio within the 400 m radius exhibited a positive link with PA density. In terms of PA diversity, factors such as green visibility rate, color-leaf plants, and green coverage ratio displayed negative associations, while the 400 m green view ratio showcased a positive impact. Notably, our study revealed a dual interplay between internal and surrounding greenery, manifesting as both collaborative and competitive dynamics that collectively shape PA. Additionally, we subjected greenery indicators to seasonal assessments, yielding insights that illuminate how urban park greenery shapes PA. These findings offer valuable guidance for future park planning and fostering environments conducive to PA.
The Influence of Aging Population in Rural Families on Farmers’ Willingness to Withdraw from Homesteads in Shenyang, Liaoning Province, China
Authors: Gu Hanlong , He Yuqing , Wang Bingyi , Qian Fengkui , Wu Yan
Published: September 2023

Population aging presents a significant global challenge. In China, the aging of the rural population coincides with inefficient rural homestead utilization. While the Chinese government has enacted policies to address this, their impact remains limited. Utilizing survey data from 403 rural families in Shenyang, Liaoning Province, China, this study applies the binary Logit and mediating effect models to analyze the impact of rural family population aging on farmers’ willingness to withdraw from homesteads with compensation and their compensation preference. Key findings include: (1) Family population aging intensifies farmers’ willingness to withdraw from homesteads, with a stronger preference for non-monetary compensation as aging increases. (2) Regarding the willingness to withdraw with compensation, farmers’ cognition of homestead security value masks the effect by 4.71%, while asset value cognition has no mediating effect. (3) With regard to promoting non-monetary compensation choices, farmers’ homestead asset value cognition fully mediates at 16.01%, but security value cognition is without mediating effect. Based on these findings, it is recommended that the government crafts tailored homestead withdrawal policies considering farmers’ family age structure. Further, efforts should aim at refining farmers’ understanding of homestead values, promoting a blend of non-monetary and monetary compensations.
Preservation of Soil Organic Carbon (SOC) through Ecosystems’ Soil Retention Services in China
Authors: Rao Enming , Xiao Yi , Lu Fei , Yang Hongbo , Ouyang Zhiyun
Published: September 2023

Soil erosion exerts a profound impact on the stocks of soil organic carbon (SOC), disrupting the carbon cycle and contributing to global warming. Through its role in mitigating soil erosion, the soil retention service of ecosystems holds the potential to stabilize and safeguard the SOC reservoir. This facet has yet to be comprehensively investigated. In this study, we quantified the preservation of SOC resulting from soil retention services in China, achieved by estimating both actual SOC erosion and potential SOC erosion using the Universal Soil Loss Equation (USLE). We find that (1) annually, SOC erosion in China amounted to 0.10 Pg C, primarily concentrated in croplands (47.8%), grasslands (21.2%), and barren lands (15.7%). Noteworthy hotspots emerged within the Soil and Water Conservation Divisions (SWCD) of key regions like the Tibetan Plateau (TP), the southwestern purple soil region (SW), and the karst region (KT). (2) The soil retention service curtailed the loss of a substantial 4.18 Pg C of SOC per year, predominantly attributed to forest ecosystems (66.1%). Hotspots of this preservation were clustered in the SWCD of the southern red soil region (SR), KT, and TP. These outcomes highlighted the critical role of soil retention services in preventing considerable carbon losses from terrestrial ecosystems. It significantly contributes to climate change mitigation and warrants recognition as an important nature-based solution in the pursuit of carbon neutrality. Forest ecosystems emerge as paramount in SOC preservation, which will be further improved with forest restoration. Beyond addressing soil erosion, future endeavors in soil and water conservation must equally address SOC erosion to comprehensively tackle carbon loss concerns.
Exploring Land Use Management Strategies through Morphological Spatial Patterns Using a Climate–Socioeconomic-Based Land Use Simulation Modeling Framework
Authors: Xie Yusong , Fukamachi Katsue , Wang Wen , Shibata Shozo
Published: September 2023

Facing future complex climate changes and global economic fluctuations, land use and land cover (LULC) simulation is recognized as an important initiative to support government decision-making. In this study, a comprehensive LULC simulation modeling framework was proposed based on the PLUS and InVEST models. The Kinki metropolis in Japan was chosen as a case to simulate future LULC changes under four SSP–RCP (126, 245, 370, and 585) scenarios, and to calculate carbon storage (CS) from 2040 to 2100. The results show that cultivated land will decrease while forests will increase, except under scenario SSP585. The artificial surface will increase except under SSP370. The CS changes are significantly correlated with forest area changes. Furthermore, this study highlights the significance of analyzing and discussing future LULCs under wide-area planning. Spatial pattern, morphological spatial pattern analysis (MSPA), and Pearson correlation analysis were used to explore the characteristics of the LULC types. The results reveal that the prefectures within the Kinki metropolitan area can be classified into three groups based on the spatial pattern indices change of the artificial surface. Most cultivated land is concentrated in important patches and corridors (area larger than 40,000 m2), accounting for over 90% of the total area, while the number is less than 25%. Forests will become more aggregated, and different MSPA classes will have varying impacts on CS changes. This study comprehensively analyzed and validated the feasibility of the simulation results from different LULC perspectives, comparing the similarities and differences in the development of prefectures. Additionally, this research provides a comprehensive framework for integrating simulated LULC types with policy discussions to better guide LULC planning and policy formulation in metropolitan Kinki.
Risk Analysis of Transport Requalification Projects in the Urban Mobility Problem Caused by a Mining Disaster
Authors: Fontana Marcele Elisa , Levino Natallya de Almeida , Leão José , Guarnieri Patrícia , Sinesio Emerson Philipe
Published: September 2023

Background: This paper proposes a risk analysis of transport requalification projects in the urban mobility problem caused by a mining disaster related to irregular rock salt extraction in the city of Maceió, Brazil. Methods: The model is composed of three main steps: problem definition, risk management, and decision analysis. For this purpose, we used the Picture Fuzzy-Delphi method for data collection and experts’ judgment elicitation and the Delphi method was used to assess the problem without interference from others. In addition, we used Picture Fuzzy Sets (PFSs) to incorporate uncertain information in the decision-making process. Results: The results of the proposed model demonstrated consistency and relevance to the discussion. The application of methods shows the risks of the project based on a general perspective. It evaluates the sustainability tripod: economic, environmental, and social points of view, assessing the occurrence risk and intensity of the risk. Conclusions: The main objective of the work was achieved; however, some limitations of this study are related to the methods used to assess risks and the options of projects of requalification available at the moment of data analysis. This paper contributes because it systematizes the risk management of projects related to requalification in urban mobility.
Lubricant-Free Thermoforming Mold Using Pulse Electrochemical Polishing
Authors: Kwak Seong Ung , Kim Uk Su , Park Jeong Woo
Published: September 2023

Thermoforming (TF) is a process used for fabricating products by applying heat and vacuum pressure to a plastic film or plate. Typically, TF molds require post-processing, resulting in additional costs and time consumption. Furthermore, continuous application of lubricant is necessary to prevent corrosion and facilitate mold release. Electrochemical polishing (ECP) is a technique used to achieve a polished surface on metal through an electrochemical reaction. In this research, a novel approach is proposed as a solution to the need for lubricants and manual post-processing in mold preparation, utilizing pulse electrochemical polishing (PECP). A comparative analysis is conducted on the reproducibility of products and the forces required for mold release among molds prepared using PECP, lubricated molds, and unpolished molds. To assess product reproducibility, the radii of curvature of all mold steps and grooves are determined and compared. Furthermore, peeling tests are conducted to estimate the forces required for mold release. Product surface evaluation is performed using atomic force microscopy, while lateral force microscopy is employed to measure the reductions in surface frictional force achieved by PECP.
Feasibility Review of Aerated Materials Application in 3D Concrete Printing
Authors: Rudziewicz Magdalena , Maroszek Marcin , Góra Mateusz , Dziura Paweł , Mróz Katarzyna , Hager Izabela , Hebda Marek
Published: September 2023

Recent years have witnessed a growing global interest in 3D concrete printing technology due to its economic and scientific advantages. The application of foamed concrete, renowned for its exceptional thermal and acoustic insulation properties, not only holds economic attractiveness but also aligns seamlessly with the principles of sustainable development. This study explores various solutions related to 3D printing technology in construction, discussing the design, production, and properties of foamed concrete mixtures. The integration of 3D printing and the potential for automating the entire process offers opportunities to boost productivity and reduce construction costs. Furthermore, the utilization of foamed concrete with its commendable insulation properties will enable a reduction in the usage of materials other than concrete (e.g., mineral wool, facade mesh, and polystyrene), significantly facilitating the recycling process during building demolition. This, in turn, will lead to the preservation of nonrenewable natural resources and a decrease in CO2 emissions. Despite the promising results, there have been limited studies focusing on 3D printing with foamed materials, whereas a survey of the existing body of literature indicates a notable absence of endeavors pertaining to the utilization of aerated concrete within the realm of 3D printing, especially geopolymer composites (GP) and hybrid geopolymer composites (HGP). The outcomes delineated in the ensuing discourse are demonstrative for conventionally used materials rather than the additive manufacturing variant. Hence, this work aims to systematically review existing practices and techniques related to producing foamed concrete with 3D printing technology. This analysis also contributes to the establishment of a foundational framework and furnishes a preliminary basis upon which future endeavors aimed at the 3D printing of aerated concrete can be embarked. The findings from the literature analysis justify the desirability of continuing research on this topic, particularly when considering the potential for large-scale industrial implementation. This article provides a comprehensive state of the knowledge on the development of 3D printing techniques for foamed concrete mixtures. By consolidating and analyzing findings from different studies, this article offers insights into the advancements, challenges, and potential applications of foamed concrete in additive manufacturing processes. This, in turn, contributes to the overall understanding and advancement of 3D printing technologies using foamed concrete as a versatile and sustainable construction material. The encouraging results obtained from the analysis further underscore the need for the continued exploration of 3D printing, especially with an eye towards its industrial-scale implementation.
Magnetic Properties of the Soft Magnetic Composites Prepared Using Mixtures of Carbonyl Iron, FeSiCr, and FeSiAl Alloy Powders
Authors: Hsiang Hsing-I , Fan Liang-Fang
Published: September 2023

The effect of carbonyl iron powder, FeSiCr alloy powder, and annealed FeSiAl alloy powder, both individually and in binary combinations, on the density, microstructure, and magnetic properties (including permeability and power loss) of inductors manufactured by molding compaction was investigated in this study. The investigation demonstrates that hysteresis loss dominates power loss in the tested frequency range. Due to higher compacted density and reduced coercivity, adding 50% carbonyl iron powder to annealed powder resulted in the lowest hysteresis loss, allowing for domain wall movement. On the other hand, adding 50% FeSiCr alloy powder to annealed powder resulted in higher hysteresis loss due to impurity components hindering domain wall motion. Due to extreme plastic deformation, the carbonyl iron powder and FeSiCr alloy powder combinations displayed the most significant hysteresis loss. Eddy current loss followed the same trends as hysteresis loss in the mixtures. This study provides important insights for refining the soft magnetic composite design to obtain higher magnetic performance, while minimizing power loss.
Electromechanical Coupling in Collagen Measured under Increasing Relative Humidity
Authors: Bazaid Arwa , Zhang Fengyuan , Zhang Qiancheng , Neumayer Sabine , Denning Denise , Habelitz Stefan , Marina Ferreira Ana , Rodriguez Brian J.
Published: September 2023

The functional role of collagen piezoelectricity has been under debate since the discovery of piezoelectricity in bone in 1957. The possibility that piezoelectricity plays a role in bone remodeling has generated interest in the investigation of this effect in relevant physiological conditions; however, there are conflicting reports as to whether collagen is piezoelectric in a humid environment. In macroscale measurements, the piezoelectricity in hydrated tendon has been shown to be insignificant compared to dehydrated tendon, whereas, at the nanoscale, the piezoelectric effect has been observed in both dry and wet bone using piezoresponse force microscopy (PFM). In this work, the electromechanical properties of type I collagen from a rat tail tendon have been investigated at the nanoscale as a function of humidity using lateral PFM (LPFM) for the first time. The relative humidity (RH) was varied from 10% to 70%, allowing the piezoelectric behavior to be studied dry, humid, as well as in the hydrated range for collagen in physiological bone (12% moisture content, corresponding to 40–50% RH). The results show that collagen piezoresponse can be measured across the humidity range studied, suggesting that piezoelectricity remains a property of collagen at a biologically relevant humidity.
Influence of Lattice Mismatch on Structural and Functional Properties of Epitaxial Ba0.7Sr0.3TiO3 Thin Films
Authors: Wawra Jonas , Nielsch Kornelius , Hühne Ruben
Published: September 2023

Substrate-induced strains can significantly influence the structural properties of epitaxial thin films. In ferroelectrics, this might lead to significant changes in the functional properties due to the strong electromechanical coupling in those materials. To study this in more detail, epitaxial Ba0.7Sr0.3TiO3 films, which have a perovskite structure and a structural phase transition close to room temperature, were grown with different thicknesses on REScO3 (RE–rare earth element) substrates having a smaller lattice mismatch compared to SrTiO3. A fully strained SrRuO3 bottom electrode and Pt top contacts were used to achieve a capacitor-like architecture. Different X-ray diffraction techniques were applied to study the microstructure of the films. Epitaxial films with a higher crystalline quality were obtained on scandates in comparison to SrTiO3, whereas the strain state of the functional layer was strongly dependent on the chosen substrate and the thickness. Differences in permittivity and a non-linear polarization behavior were observed at higher temperatures, suggesting that ferroelectricity is supressed under tensile strain conditions in contrast to compressive strain for our measurement configuration, while a similar reentrant relaxor-like behavior was found in all studied layers below 0°C.
Distribution of Electron Density in Self-Assembled One-Dimensional Chains of Si Atoms
Authors: Jałochowski Mieczysław , Kwapiński Tomasz
Published: September 2023

Scanning tunneling microscopy measurements of height profiles, along the chains of Si atoms on the terrace edges of a perfectly ordered Si(553)-Au surface, reveal an STM bias-dependent mixed periodicity with periods of one, two and one and a half lattice constants. The simple linear chain model usually observed with STM cannot explain the unexpected fractional periodicity in the height profile. It was found that the edge Si chain stands for, in fact, a zigzag structure, which is composed of two neighboring rows of Si atoms and was detected in the STM experiments. Tight-binding calculations of the local density of states and charge occupancy along the chain explain the voltage-dependent modulations of the STM profiles and show that oscillation periods are determined mainly by the surface and STM tip Fermi energies.
Efficient CsPbBr3 Quantum-Dot Light-Emitting Diodes Using Sputtered NiO Films as Hole Injection Layers
Authors: Huang Pao-Hsun , Chen Sih-An , Chao Li-Wei , Xie Jia-Xun , Liao Ching-Yu , Tseng Zong-Liang , Chen Sheng-Hui
Published: September 2023

Perovskite quantum dots (QDs) have showed excellent optoelectronic properties to extend the application range of novel solid-state lighting, such as perovskite QD based LEDs (QD-LEDs). However, the traditional device structure of perovskite QD-LEDs employed PEDOT:PSS as a hole inject layer (HIL), which impairs stability due to acidic surface characteristics. This study proposes the sputtered NiO films as an HIL to replace acidic PEDOT:PSS. The NiO films with significantly different characteristics were prepared by controlling the sputtering parameters to investigate the devices’ performance of NiO-based CsPbBr3 QD-LEDs. The optimized device showed an excellent performance with maxima luminescence of 20,118 cd/m2 and an external quantum efficiency (EQE) up to 3.63%.
Process Optimization, Morphology, Structure, and Adhesive Strength of Electrodeposited Ni–Fe–Graphene Composite Coating on the 7075 Aluminum Alloy
Authors: Li Na , Zhang Lan , Ma Huizhong , Li Qiao , Sun Xingke
Published: September 2023

The process parameters of electrodeposited Ni–Fe–graphene composite coating on the 7075 aluminum alloy were optimized by the orthogonal experiment. The optimized process parameters were determined as follows: graphene concentration of 1 g L−1, current density of 9 A dm−2, agitation speed of 250 r min−1, and temperature of 60 °C, on the basis of hardness and friction coefficient. The Ni–Fe–graphene composite coating shows an increment of 393.0% in hardness and a decrement of 55.9% in friction coefficient in comparison with 7075 aluminum alloy substrate. The Ni–Fe–graphene composite coating binds tightly to 7075 aluminum alloy with adhesion strength of higher than 6.895 MPa. These make contributions to provide effective protection for aluminum alloys. Surface morphology and corrosion morphology, as well as morphology of the side bound to the substrate, were characterized. The scattered asperities on the surface were proven to be graphene nanoplatelets being wrapped by Ni–Fe, which comprehensively reveals the formation of asperities.
Effect of Cs+ Doping on the Carrier Dynamics of MAPbI3 Perovskite
Authors: Duan Menghan , Wang Yunpeng , Zhang Pingli , Du Luchao
Published: September 2023

Organic inorganic perovskite materials have received increasing attention in the optoelectronic field because of their unique properties. The ultrafast dynamics of photogenerated carriers determine photoelectric conversion efficiency, thus, it is feasible to influence the dynamics behavior of photogenerated carriers by regulating A-site cations. This paper mainly used transient absorption spectra (TAS) technology to study the photogenerated carriers relaxation processes of organic–inorganic perovskite CsxMA1−xPbI3 materials at different x values. Three sets of time constants were obtained by global fitting at different values of x. The experimental results showed that the crystal structure of perovskite could be affected by adjusting the Cs+ doping amount, thereby regulating the carrier dynamics. The appropriate amount of A-cation doping not only maintained the organic–inorganic perovskite crystal phase, but also prolonged the photogenerated carrier’s lifetime. The 10% Cs+ doping CsxMA1−xPbI3 perovskite has potential for solar cell applications. We hope that our research can provide dynamics support for the development of organic–inorganic perovskite in solar cells.
Residual Properties of Geopolymer Concrete for Post-Fire Evaluation of Structures
Authors: Kanagaraj Balamurali , Anand Nammalvar , Andrushia Diana , Kodur Venkatesh
Published: September 2023

The research focuses on effectively utilizing industrial by-products, namely fly ash (FA) and ground granulated blast furnace slag (GGBS), to develop sustainable construction materials that can help reduce carbon emissions in the construction industry. Geopolymer mix design using these by-products is identified as a potential solution. The study investigates the impact of different water to binder ratios (W/B) ranging from 0.4 to 0.6 on the residual properties, including compressive strength (CS), of geopolymer concrete (GPC), in accordance with Indian Standard for Alkali activated concrete. Lower W/B ratios were found to result in a more compact and less porous microstructure in the GPC. Additionally, the research explores the post-fire performance of GPC with varying grades (M10, M20, M30, & M40) and different W/B ratios, following the ISO 834 standard fire curve. It was observed that concrete samples exposed to elevated temperatures displayed a more porous microstructure. The mass loss of GPC with 0.4 W/B was found to be 2.3–5.9% and for 0.6 W/B ratio, the loss was found to be 3–6.5%, after exposing to 30-, 60-, 90-, and 120-min of heating. In the case of strength loss, for 0.4 W/B ratio, the loss was 36.81–77.09%, and for 0.6 W/B ratio the loss was 38.3–100%, after exposing to 30-, 60-, 90-, and 120-min of heating. Overall, the findings suggest that optimizing the W/B ratio in geopolymer concrete can enhance its compressive strength, as well as residual properties, and contribute to its suitability as a sustainable construction material. However, the response to elevated temperatures should also be considered to ensure its performance in fire scenarios.
Effect of Coffee and Polishing Systems on the Color Change of a Conventional Resin Composite Repaired by Universal Resin Composites: An In Vitro Study
Authors: Aksoy Vaizoğlu Gözde , Ulusoy Nuran , Güleç Alagöz Laden
Published: September 2023

The purpose of this study was to evaluate the color stability of repaired aesthetic restorative resin matrix materials after immersion in coffee and the effect of polishing systems after staining. One hundred and eighty cylindrical discs (8 mm × 2 mm) were prepared using a conventional nano-fill resin composite (Clearfil Majesty Esthetic A2 shade) with round cavities (3 × 1 mm). Cavities were repaired by three resin composite materials: Clearfil Majesty Esthetic A2 shade, one-shaded nano-fill resin composite (Omnichroma) and group-shaded nano-hybrid resin composite (Optishade, medium shade). Each group was polished with three polishing systems (n = 20); aluminum oxide (Soflex Spiral Wheels, 3M ESPE), silicon carbide (Occlubrush, Kerr, CA, USA) and diamond particulate (Twist Dia Spiral Wheels, Kuraray, Okayama, Japan). Color change (ΔE00) measurements were performed with a spectrophotometer at the baseline. Half of the polished samples were either kept in distilled water or immersed in coffee for 15 days, and color measurements were repeated before and after polishing. Statistical analysis was performed using the Kruskal–Wallis test. Repaired samples showed different color correspondence values in all groups. All three restorative materials showed significant color changes (ΔE00) after immersion in coffee (p ≤ 0.05). Repolishing of stained samples showed color improvement values in all groups. The content of the polishing system played an important role in removing the stains.
Multi-Objective Optimization of the Process Parameters of a Grinding Robot Using LSTM-MLP-NSGAII
Authors: Li Ruizhi , Wang Zipeng , Yan Jihong
Published: September 2023

Grinding robots are widely used in the automotive, mechanical processing, aerospace industries, among others, due to their strong adaptability, high safety and intelligence. The grinding process parameters are the main factors that affect the quality and efficiency of grinding robots. However, it is difficult to obtain the optimal combination of the grinding process parameters only by manual experience. This study proposes an artificial intelligence-based method for optimizing the process parameters of a grinding robot using neural networks and a genetic algorithm, with the aim to reduce the workpiece surface roughness and shorten the grinding time. Specifically, this is the first study utilizing a multi-objective optimization approach to optimize the process parameters of a grinding robot. Based on the experimental data of the grinding robot ROKAE XB7, the long short-term memory (LSTM) and multilayer perceptron (MLP) neural networks were trained to fit the quantitative relationships between the process parameters of the grinding robot, such as feed rate, spindle pressure and pneumatic motor pressure, and the result of grinding surface roughness and grinding time. After that, the non-dominated sorting genetic algorithm II (NSGA-II) was used to calculate the Pareto optimal process parameter combinations using the trained LSTM and MPL model as the objective function. Compared with the method based on manual experience, the process parameters optimized with this method achieved a reduction in surface roughness of at least 13.62% and a reduction in the whole grinding process time of 28%. The excellent grinding results obtained for grinding time and surface roughness validated the feasibility and efficiency of the proposed multi-objective method for the optimization of grinding robots’ process parameters in practical manufacturing applications.
A Study of Frequency Domain Reflectometry Technique for High-Voltage Rotating Machine Winding Condition Assessment
Authors: Cheng Jialu , Zhang Yizhou , Yun Hao , Wang Liang , Taylor Nathaniel
Published: September 2023

Detecting and locating local degradations at an incipient stage is very important for mission-critical high-voltage rotating machines. One particular challenge in the existing testing techniques is that the characteristic of a local incipient defect is not prominent due to various factors such as averaging with the healthy remainder, attenuation in signal propagation, interference, and varied operating conditions. This paper proposes and investigates the frequency domain reflectometry (FDR) technique based on the scattering parameter measurement. The FDR result presents the object length, wave impedance, and reflections due to impedance discontinuity along the measured windings. Experiments were performed on two commercial coils with artificially created defects. These defects include turn-to-turn short, surface creepage, loose coils, insufficient end-winding spacing, and local overheating, which are commonly seen in practice. Two practical water pumps in the field were also selected for investigation. The study outcome shows that FDR can identify and locate structural and insulation degradation in both shielded and unshielded objects with good sensitivity. This makes FDR a complementary technique for machine fault diagnosis and aging assessment.
Adaptive Control of M3C-Based Variable Speed Drive for Multiple Permanent-Magnet-Synchronous-Motor-Driven Centrifugal Pumps
Authors: Mendoza-Becker Rodrigo , Travieso-Torres Juan Carlos , Díaz Matías
Published: September 2023

There has been growing interest in using permanent magnet synchronous motors (PMSMs) for pumping applications to improve energy efficiency. One promising approach for powering these motors in variable speed applications is using an M3C due to its inherent fault tolerance capability. However, M3C converters require a more complex control system than simpler converters. For instance, a basic M3C control system for power transmission requires seventeen PI controllers, whose fixed adjustment depends on the M3C’s dynamical model parameters’ value knowledge, needing initial extensive and time-consuming testing to obtain it. As an alternative, we propose an adaptive M3C control system for variable speed drives powering multiple PMSM-driven centrifugal pumps that reduces the number of controllers to six. Furthermore, the proposal does not require initial knowledge of the converter, motor, or load parameters, making it more practical and versatile. The proposal introduces an ad hoc hybrid passivity-based model reference adaptive controller in cascade with a passivity-based control. It was validated through theoretical stability proof and comparative simulation results with a basic control system under normal and fault operations. As a result, the proposal effectively follows the required rotor speed while enhancing performance by decreasing the current consumption and recovering from a 10% input phase imbalance, a cell short circuit, an open cell, and parameters changes of the motor–pump set.
Advancements in 3D-Printed Novel Nylon-6: A Taguchi Method for Surface Quality Sustainability and Mechanical Properties
Authors: Mushtaq Ray Tahir , Alkahtani Mohammed , Khan Aqib Mashood , Abidi Mustufa Haider
Published: September 2023

This research aims to establish the ideal settings for Nylon-6 (PA6) three-dimensional printing utilizing the fused filament production process and examine the resultant surface roughness. ANOVA, S/N ratio, and modeling are explained, along with their application in identifying the ideal values for surface roughness, sustainability, and mechanical properties. Average-surface roughness (Ra), root-mean-squared surface roughness (Rq), print time (PT), print energy (PE), and tensile testing (T) were explored as response parameters to identify the impact of PA6 parameters (layer thickness, extrusion temperature, print speed, and infill density). Tests of validity demonstrated a significant decline in Ra, Rq, PE, PT, and T for the ideal values of the developed product of 10.58 µm and 13.3 µm, 23 min, 0.13 kWh, and 42.7 Mpa, respectively. Ra, Rq, PT, PE, and T have all been optimized using Taguchi techniques as a preliminary step towards application in future research and prototypes.
Analysis of the Cutting Performance of Coated Micro-Textured Bionic Tools for Dry Cutting AISI 52100
Authors: Li Qinghua , Ma Chunlu , Wang Chunyu , Wang Baizhong , Zhang Shihong
Published: September 2023

In order to solve the problem of poor stability of hard brittle material in cutting process, a 45° groove micro-textured composite bionic tool was proposed. Under the same cutting parameters and conditions, the temperature rise and cutting force can be suppressed, and the tool stability can be reduced. Firstly, the design tool was modeled in three dimensions and the optimal bionic tool structure was optimized by finite element simulation technology. Secondly, four microstructures were constructed on the basis of biomimetic tools, and the optimum microstructures were selected based on shear force, stress distribution and chip discharge capacity. The smallest microstructure size parameters were obtained by changing the spacing of microstructures. Finally, on the basis of optimizing the micro-textured biomimetic tool, the surface of the tool was coated, and the influence of coating material on tool performance was discussed. The results showed that the cutting fracture rate of the material increased and the cutting accumulation phenomenon was alleviated obviously when the 45° chute micro-textured bionic tool with composite coating was used for machining. The cutting stability of the tool was enhanced and chip adhesion was reduced when cutting forces and cutting temperatures were reduced. At the same time, compared with conventional tools, the main cutting force and radial force decreased by 35% and 62%, and the cutting temperature decreased by 3.5%. With the decrease in cutting force and cutting temperature, the stability of cutting was enhanced and the phenomenon of chip adhesion on the tool surface was reduced.
Prediction of Stress and Deformation Caused by Magnetic Attraction Force in Modulation Elements in a Magnetically Geared Machine Using Subdomain Modeling
Authors: Nguyen Manh-Dung , Kim Su-Min , Lee Jeong-In , Shin Hyo-Seob , Lee Young-Keun , Lee Hoon-Ki , Shin Kyung-Hun , Kim Yong-Joo , Phung Anh-Tuan , Choi Jang-Young
Published: September 2023

This study presents an approach for calculating the stress and deformation increase in the modulation of magnetically geared machines using a mathematical method. An analytical method is employed to obtain the magnetic force density acting on the modulation components. Afterward, the proposed mathematical method predicts the mechanical characteristics. The 9 slots/32 poles/19 modulations model was evaluated via a comparison with the finite element method simulation.
Supply Chain 4.0: A Machine Learning-Based Bayesian-Optimized LightGBM Model for Predicting Supply Chain Risk
Authors: Sani Shehu , Xia Hanbing , Milisavljevic-Syed Jelena , Salonitis Konstantinos
Published: September 2023

In today’s intricate and dynamic world, Supply Chain Management (SCM) is encountering escalating difficulties in relation to aspects such as disruptions, globalisation and complexity, and demand volatility. Consequently, companies are turning to data-driven technologies such as machine learning to overcome these challenges. Traditional approaches to SCM lack the ability to predict risks accurately due to their computational complexity. In the present research, a hybrid Bayesian-optimized Light Gradient-Boosting Machine (LightGBM) model, which accurately forecasts backorder risk within SCM, has been developed. The methodology employed encompasses the creation of a mathematical classification model and utilises diverse machine learning algorithms to predict the risks associated with backorders in a supply chain. The proposed LightGBM model outperforms other methods and offers computational efficiency, making it a valuable tool for risk prediction in supply chain management.
Controlling COVID-19 Spreading: A Three-Level Algorithm
Authors: Dieguez Giovanni , Batistela Cristiane , Piqueira José R. C.
Published: September 2023

As the main methods of the coronavirus disease (COVID-19) transmission are air and physical contact, actions to mitigate and suppress its spread must be developed in order to change population dynamics and provide efficient control strategies. Here, these actions are described as a simple heuristic framework to establish public policies. Two control systems were studied: the first organized in the form of an algorithm stratified into three levels and the second as a minimization problem similar to optimal control strategies, applied to both social distancing and vaccination. The possible effects of these actions are modeled and applied to an extension of the Susceptible - Infected - Removed (SIR) compartmental model. The control system is developed, which is organized in the form of an algorithm stratified into three levels. These levels intend to represent social distancing strategies implemented by sanitary authorities around the globe, representing stronger or weaker grades of isolation intensity according to the ability of the healthcare system to cope with symptomatic individuals. The algorithm control is applied in a simulation, and the results give evidence of the effectiveness of the procedures adopted against the coronavirus. The model dynamics are analyzed and validated with simulations considering parameters obtained from epidemiological data from Brazil and Uruguay and in a more detailed way for three Brazilian states: São Paulo, Minas Gerais and Rio de Janeiro. The model was validated using cumulative data on cases and deaths. For cases of death, the results were satisfactory, while for case data, the response was reasonable, considering the possibility of adding delays or variations in parameters in the model. In addition, the effective reproduction number was proposed for the cities studied in Brazil, the result being relevant because it has a qualitative behavior similar to that published by official centers. This paper also discusses the implementation and optimization of social distancing and vaccination control strategies, considering different parameters and their effects on reducing the number of cases and deaths. Model simulations present promising results for developing strategies to attack COVID-19 dissemination.