Materials最新文献_第6页

Advanced Dental Materials: From Design to Application 先进牙科材料：从设计到应用

Materials Pub Date : 2024-07-25 DOI: 10.3390/ma17153667

Josip Kranjčić, Tina Poklepovic Pericic

引用次数: 0

The Influence of Lanthanum Admixture on Microstructure and Electrophysical Properties of Lead-Free Barium Iron Niobate Ceramics 掺杂镧对无铅铌铁钡陶瓷微观结构和电物理特性的影响

Materials Pub Date : 2024-07-25 DOI: 10.3390/ma17153666

D. Bochenek, D. Brzezińska, P. Niemiec, L. Kozielski

{"title":"The Influence of Lanthanum Admixture on Microstructure and Electrophysical Properties of Lead-Free Barium Iron Niobate Ceramics","authors":"D. Bochenek, D. Brzezińska, P. Niemiec, L. Kozielski","doi":"10.3390/ma17153666","DOIUrl":"https://doi.org/10.3390/ma17153666","url":null,"abstract":"This article presents the research results of lead-free Ba1−3/2xLax(Fe0.5Nb0.5)O3 (BFNxLa) ceramic materials doped with La (x = 0.00–0.06) obtained via the solid-state reaction method. The tests of the BFNxLa ceramic samples included structural (X-ray), morphological (SEM, EDS, EPMA), DC electrical conductivity, and dielectric measurements. For all BFNxLa ceramic samples, the X-ray tests revealed a perovskite-type cubic structure with the space group Pm3¯m. In the case of the samples with the highest amount of lanthanum, i.e., for x = 0.04 (BFN4La) and x = 0.06 (BFN6La), the X-ray analysis also showed a small amount of pyrochlore LaNbO4 secondary phase. In the microstructure of BFNxLa ceramic samples, the average grain size decreases with increasing La content, affecting their dielectric properties. The BFN ceramics show relaxation properties, diffusion phase transition, and very high permittivity at room temperature (56,750 for 1 kHz). The admixture of lanthanum diminishes the permittivity values but effectively reduces the dielectric loss and electrical conductivity of the BFNxLa ceramic samples. All BFNxLa samples show a Debye-like relaxation behavior at lower frequencies; the frequency dispersion of the dielectric constant becomes weaker with increasing admixtures of lanthanum. Research has shown that using an appropriate amount of lanthanum introduced to BFN can obtain high permittivity values while decreasing dielectric loss and electrical conductivity, which predisposes them to energy storage applications.","PeriodicalId":503043,"journal":{"name":"Materials","volume":"21 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141802438","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Effect of Degradation of Polylactic Acid (PLA) on Dynamic Mechanical Response of 3D Printed Lattice Structures 聚乳酸（PLA）降解对 3D 打印晶格结构动态机械响应的影响

Materials Pub Date : 2024-07-25 DOI: 10.3390/ma17153674

Reza Hedayati, Melikasadat Alavi, M. Sadighi

{"title":"Effect of Degradation of Polylactic Acid (PLA) on Dynamic Mechanical Response of 3D Printed Lattice Structures","authors":"Reza Hedayati, Melikasadat Alavi, M. Sadighi","doi":"10.3390/ma17153674","DOIUrl":"https://doi.org/10.3390/ma17153674","url":null,"abstract":"Material-extrusion-based 3D printing with polylactic acid (PLA) has transformed the production of lightweight lattice structures with a high strength-to-weight ratio for various industries. While PLA offers advantages such as eco-friendliness, affordability, and printability, its mechanical properties degrade due to environmental factors. This study investigated the impact resistance of PLA lattice structures subjected to material degradation under room temperature, humidity, and natural light exposure. Four lattice core types (auxetic, negative-to-positive (NTP) gradient in terms of Poisson’s ratio, positive-to-negative (PTN) gradient in terms of Poisson’s ratio, and honeycomb) were analyzed for variations in mechanical properties due to declines in yield stress and failure strain. Mechanical testing and numerical simulations at various yield stress and failure strain levels evaluated the degradation effect, using undegraded material as a reference. The results showed that structures with a negative Poisson’s ratio exhibited superior resistance to local crushing despite material weakening. Reducing the material’s brittleness (failure strain) had a greater impact on impact response compared to reducing its yield stress. This study also revealed the potential of gradient cores, which exhibited a balance between strength (maintaining similar peak force to auxetic cores around 800 N) and energy absorption (up to 40% higher than auxetic cores) under moderate degradation (yield strength and failure strain at 60% and 80% of reference values). These findings suggest that gradient structures with varying Poisson’s ratios employing auxetic designs are valuable choices for AM parts requiring both strength and resilience in variable environmental conditions.","PeriodicalId":503043,"journal":{"name":"Materials","volume":"64 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141802510","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Differentiation between Hydrolytic and Thermo-Oxidative Degradation of Poly(lactic acid) and Poly(lactic acid)/Starch Composites in Warm and Humid Environments 聚乳酸和聚乳酸/淀粉复合材料在温暖潮湿环境中的水解降解与热氧化降解的区别

Materials Pub Date : 2024-07-25 DOI: 10.3390/ma17153683

Victoria Goetjes, Jan-Christoph Zarges, Hans-Peter Heim

{"title":"Differentiation between Hydrolytic and Thermo-Oxidative Degradation of Poly(lactic acid) and Poly(lactic acid)/Starch Composites in Warm and Humid Environments","authors":"Victoria Goetjes, Jan-Christoph Zarges, Hans-Peter Heim","doi":"10.3390/ma17153683","DOIUrl":"https://doi.org/10.3390/ma17153683","url":null,"abstract":"For the application of poly(lactic acid) (PLA) and PLA/starch composites in technical components such as toys, it is essential to know their degradation behavior under relevant application conditions in a hydrothermal environment. For this purpose, composites made from PLA and native potato starch were produced using twin-screw extruders and then processed into test specimens, which were then subjected to various one-week ageing processes with varying temperatures (23, 50, 70, 90 °C) and humidity levels (10, 50, 75, 90%). This was followed by mechanical characterization (tensile test) and identification of degradation using Gel Permeation Chromatography (GPC), Thermogravimetric Analysis (TGA), Fourier Transform Infrared Spectroscopy (FTIR), and Nuclear Magnetic Resonance spectroscopy (NMR). With increasing temperature and humidity, there was a clear degradation of the PLA, which could be reduced or slowed down by adding 50 wt.% starch, due to increased crystallinity. Hydrolysis was identified as the main degradation mechanism for PLA and PLA/starch composites, especially above the glass transition temperature, with thermo-oxidative degradation also playing a subordinate role. Both hydrolytic degradation and thermo-oxidative degradation led to a reduction in mechanical properties such as tensile strength.","PeriodicalId":503043,"journal":{"name":"Materials","volume":"15 12","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141803167","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The Identification of Leidenfrost Phenomenon Formation on TiO2-Coated Surfaces and the Modelling of Heat Transfer Processes 识别 TiO2 涂层表面形成的莱顿弗罗斯特现象并建立传热过程模型

Materials Pub Date : 2024-07-25 DOI: 10.3390/ma17153687

M. Maziukienė, N. Striūgas, L. Vorotinskienė, R. Skvorčinskienė, M. Urbonavičius

{"title":"The Identification of Leidenfrost Phenomenon Formation on TiO2-Coated Surfaces and the Modelling of Heat Transfer Processes","authors":"M. Maziukienė, N. Striūgas, L. Vorotinskienė, R. Skvorčinskienė, M. Urbonavičius","doi":"10.3390/ma17153687","DOIUrl":"https://doi.org/10.3390/ma17153687","url":null,"abstract":"Experiments on specimen cooling dynamics and possible film boiling around a body are very important in various industrial applications, such as nucleate boiling, to decrease drag reduction or achieve better surface properties in coating technologies. The objective of this study was to investigate the interaction between the heat transfer processes and cooling dynamics of a sample in different boundary conditions. This article presents new experimental data on specimens coated with Al–TiO2 film and Leidenfrost phenomenon (LP) formation on the film’s surface. Furthermore, this manuscript presents numerical heat and mass transfer parameter results. The comparative analysis of new experiments on Al–TiO2 film specimens and other coatings such as polished aluminium, Al–MgO, Al–MgH2 and Al–TiH2 provides further detail on oxide and hydride materials. In the experimental cooling dynamics experiments, specimens were heated up to 450 °C, while the sub-cooling water temperatures were 14*‒20 °C (room temperature), 40 °C and 60 °C. The specimens’ cooling dynamics were calculated by applying Newton’s cooling law, and heat transfer was estimated by calculating the heat flux q transferred from the specimens’ surface and the Bi parameter. The metadata results from the performed experiments were used to numerically model the cooling dynamics curves for different material specimens. Approximated polynomial equations are proposed for the polished aluminium, Al–TiO2, Al–MgO, Al–MgH2 and Al–TiH2 materials. The provided comparative analysis makes it possible to see the differences between oxides and hydrides and to choose materials for practical application in the industrial sector. The presented results could also be used in software packages to model heat transfer processes.","PeriodicalId":503043,"journal":{"name":"Materials","volume":"52 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141803999","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Concrete Defect Localization Based on Multilevel Convolutional Neural Networks 基于多级卷积神经网络的混凝土缺陷定位技术

Materials Pub Date : 2024-07-25 DOI: 10.3390/ma17153685

Yameng Wang, Lihua Wang, Wenjing Ye, Fengyi Zhang, Yongdong Pan, Yan Li

{"title":"Concrete Defect Localization Based on Multilevel Convolutional Neural Networks","authors":"Yameng Wang, Lihua Wang, Wenjing Ye, Fengyi Zhang, Yongdong Pan, Yan Li","doi":"10.3390/ma17153685","DOIUrl":"https://doi.org/10.3390/ma17153685","url":null,"abstract":"Concrete structures frequently manifest diverse defects throughout their manufacturing and usage processes due to factors such as design, construction, environmental conditions and distress mechanisms. In this paper, a multilevel convolutional neural network (CNN) combined with array ultrasonic testing (AUT) is proposed for identifying the locations of hole defects in concrete structures. By refining the detection area layer by layer, AUT is used to collect ultrasonic signals containing hole defect information, and the original echo signal is input to CNN for the classification of hole locations. The advantage of the proposed method is that the corresponding defect location information can be obtained directly from the input ultrasonic signal without manual discrimination. It effectively addresses the issue of traditional methods being insufficiently accurate when dealing with complex structures or hidden defects. The analysis process is as follows. First, COMSOL-Multiphysics finite element software is utilized to simulate the AUT detection process and generate a large amount of ultrasonic echo data. Next, the extracted signal data are trained and learned using the proposed multilevel CNN approach to achieve progressive localization of internal structural defects. Afterwards, a comparative analysis is conducted between the proposed multilevel CNN method and traditional CNN approaches. The results show that the defect localization accuracy of the proposed multilevel CNN approach improved from 85.38% to 95.27% compared to traditional CNN methods. Furthermore, the computation time required for this process is reduced, indicating that the method not only achieves higher recognition precision but also operates with greater efficiency. Finally, a simple experimental verification is conducted; the results show that this method has strong robustness in recognizing noisy ultrasonic signals, provides effective solutions, and can be used as a reference for future defect detection.","PeriodicalId":503043,"journal":{"name":"Materials","volume":"23 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141804182","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Effects of Using Laser Technology for Cutting Polymer Films 使用激光技术切割聚合物薄膜的效果

Materials Pub Date : 2024-07-25 DOI: 10.3390/ma17153678

Malgorzata Olender-Skóra, W. Banaś, Marian Turek, Paweł Skóra, A. Gwiazda, K. Foit, A. Sekala, Michał Stawowiak

{"title":"Effects of Using Laser Technology for Cutting Polymer Films","authors":"Malgorzata Olender-Skóra, W. Banaś, Marian Turek, Paweł Skóra, A. Gwiazda, K. Foit, A. Sekala, Michał Stawowiak","doi":"10.3390/ma17153678","DOIUrl":"https://doi.org/10.3390/ma17153678","url":null,"abstract":"In connection with the need to obtain a properly made and cut material and the appearance of the surface layer, new manufacturing technologies were used for tests, namely the laser cutting technology. This article describes the laboratory stand built for the purpose of research, as well as the possibility of using laser cutting on several sample materials (polymer films), together with an indication of the results obtained. The idea was to elaborate on the cutting technology that will be proper for manufacturing the desired type of spacers for ion-exchange membranes separating while maintaining the required level of product quality and chemical purity. The latter criterion was the basic one, due to the scope of use of the manufactured elements. This article also describes the problem encountered during the construction of the stand or during the research. The last part of this article describes the further steps of the research that will be carried out in the future along with a discussion and summary of the research performed. It is important from the point of view of the development of production technology, but also because of the characteristics of materials for the production of surface layers and coatings resistant to mechanical or thermal wear used in industry. The introduction of innovative solutions is also aimed at studying the improvement of the economics of the production of materials that are significant, in particular, for small- and medium-sized enterprises.","PeriodicalId":503043,"journal":{"name":"Materials","volume":"28 23","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141806152","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Bio-Inspired Double-Layered Hydrogel Robot with Fast Response via Thermo-Responsive Effect 受生物启发的双层水凝胶机器人通过热响应效应实现快速响应

Materials Pub Date : 2024-07-25 DOI: 10.3390/ma17153679

Yunsong Liu, Xiong Zheng

{"title":"Bio-Inspired Double-Layered Hydrogel Robot with Fast Response via Thermo-Responsive Effect","authors":"Yunsong Liu, Xiong Zheng","doi":"10.3390/ma17153679","DOIUrl":"https://doi.org/10.3390/ma17153679","url":null,"abstract":"Bio-inspired hydrogel robots have become promising due to their advantage of the interaction safety and comfort between robots and humans, while current hydrogel robots mainly focus on underwater movement due to the hydration–dehydration process of thermo-responsive hydrogels, which greatly limits their practical applications. To expand the motion of the thermo-responsive hydrogel robot to the ground, we constructed a hydrogel robot inspired by a caterpillar, which has an anisotropic double-layered structure by the interfacial diffusion polymerization method. Adding PVA and SA to PNIPAm will cause different conformation transitions. Therefore, sticking the two layers of hydrogel together will form a double-layer anisotropic structure. The ultra-high hydrophilicity of PVA and SA significantly reduces the contact angle of the hydrogel from 53.1° to about 10° and reduces its hydration time. The responsive time for bending 30° of the hydrogel robot has been greatly reduced from 1 h to half an hour through the enhancement of photo-thermal conversion and thermal conductivity via the addition of Fe3O4 nanoparticles. As a result, the fabricated hydrogel robot can achieve a high moving speed of 54.5 mm·h−1 on the ground. Additionally, the fabricated hydrogel has excellent mechanical strength and can endure significant flexibility tests. This work may pave the road for the development of soft robots and expand their applications in industry.","PeriodicalId":503043,"journal":{"name":"Materials","volume":"70 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141802703","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Summary of the Research Progress on Advanced Engineering, Processes, and Process Parameters of Rare Earth Green Metallurgy 稀土绿色冶金先进工程、工艺和工艺参数研究进展综述

Materials Pub Date : 2024-07-25 DOI: 10.3390/ma17153686

Yingqi Li, Tingan Zhang, Zhihe Dou, Wei Xie, Chuidai Lan, Guangtao Li

{"title":"Summary of the Research Progress on Advanced Engineering, Processes, and Process Parameters of Rare Earth Green Metallurgy","authors":"Yingqi Li, Tingan Zhang, Zhihe Dou, Wei Xie, Chuidai Lan, Guangtao Li","doi":"10.3390/ma17153686","DOIUrl":"https://doi.org/10.3390/ma17153686","url":null,"abstract":"The addition of rare earth metals to aluminum alloys can effectively improve their corrosion resistance and has been widely used in the aerospace and military industries. However, the current methods for the preparation of rare earth metals involve long processing steps, high energy consumption, and high carbon emissions, which severely constrains the development of aluminum alloys. Its output is further developed. To this end, this paper reviews mainstream rare earth production processes (precipitation methods, microemulsion methods, roasting-sulfuric acid leaching methods, electrochemical methods, solvent extraction methods, and ion exchange methods) to provide basic information for the green smelting of rare earth metals and help promote the development of green rare earth smelting. Based on the advantages and disadvantages of each process as well as recent research results, the optimal process parameters and production efficiency were summarized. Studies have concluded that the precipitation method is mostly used for the recovery of rare earth elements and related valuable metals from solid waste; the microemulsion method is mostly used for the preparation of nanosized rare earth alloys by doping; the roasting-sulfuric acid leaching method is mostly used for the treatment of raw rare earth ores; and the molten salt electrolysis method is a more specific method. This is a green and environmentally friendly production process. The results of this study can provide direction for the realization of green rare earth smelting and provide a reference for improving the existing rare earth smelting process.","PeriodicalId":503043,"journal":{"name":"Materials","volume":"49 11","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141803653","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Modeling of Material Removal Rate for the Fixed-Abrasive Double-Sided Planetary Grinding of a Sapphire Substrate 蓝宝石基片固定磨料双面行星磨削材料去除率建模

Materials Pub Date : 2024-07-25 DOI: 10.3390/ma17153688

Gen Chen, Zhongwei Hu, Lijuan Wang, Yue Chen

{"title":"Modeling of Material Removal Rate for the Fixed-Abrasive Double-Sided Planetary Grinding of a Sapphire Substrate","authors":"Gen Chen, Zhongwei Hu, Lijuan Wang, Yue Chen","doi":"10.3390/ma17153688","DOIUrl":"https://doi.org/10.3390/ma17153688","url":null,"abstract":"Double-sided planetary grinding (DSPG) with a fixed abrasive is widely used in sapphire substrate processing. Compared with conventional free abrasive grinding, it has the advantages of high precision, high efficiency, and environmental protection. In this study, we propose a material removal rate (MRR) model specific to the fixed-abrasive DSPG process for sapphire substrates, grounded in the trajectory length of abrasive particles. In this paper, the material removal rate model is obtained after focusing on the theoretical analysis of the effective number of abrasive grains, the indentation depth of a single abrasive grain, the length of the abrasive grain trajectory, and the groove repetition rate. To validate this model, experiments were conducted on sapphire substrates using a DSPG machine. Theoretical predictions of the material removal rate were then juxtaposed with experimental outcomes across varying grinding pressures and rotational speeds. The trends between theoretical and experimental values showed remarkable consistency, with deviations ranging between 0.2% and 39.2%, thereby substantiating the model’s validity. Moreover, leveraging the insights from this model, we optimized the disparity in the material removal rate between two surfaces of the substrate, thereby enhancing the uniformity of the machining process across both surfaces.","PeriodicalId":503043,"journal":{"name":"Materials","volume":"47 20","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141805291","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0