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Materials, Volume 15, Issue 12 (June-2 2022) – 330 articles

Cover Story (view full-size image): Dye-doped liquid crystals (LCs), which reversibly control their molecular orientation by light, have attracted great attention in the development of all-optical devices, such as smart windows. However, the sensitivity of molecular reorientation in dye-doped LCs is still low for the application to optical devices. A. Shishido et al. reported the effect of the host LC structure on the photoinduced response in oligothiophene-doped LCs. The threshold light intensity for the molecular reorientation in trifluorinated LCs was 42% lower than that in LCs without fluorine substituents. View this paper
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17 pages, 2910 KiB  
Article
Preparation and Performance of Ternesite–Ye’elimite Cement
by Yan Shen, Xi Chen, Jiang Li, Peifang Wang and Jueshi Qian
Materials 2022, 15(12), 4369; https://doi.org/10.3390/ma15124369 - 20 Jun 2022
Cited by 3 | Viewed by 1880
Abstract
Ternesite–ye’elimite (TCSA) cement is a new type of environmentally advantageous binder prepared by introducing ternesite, a reactive phase, into belite calcium sulfoaluminate cement clinker. This paper reports the laboratory production of TCSA cement by the addition of minor elements to achieve the coexistence [...] Read more.
Ternesite–ye’elimite (TCSA) cement is a new type of environmentally advantageous binder prepared by introducing ternesite, a reactive phase, into belite calcium sulfoaluminate cement clinker. This paper reports the laboratory production of TCSA cement by the addition of minor elements to achieve the coexistence of ternesite and ye’elimite. The influence of dopants on the mineralogical composition of clinkers and the clinkering conditions for the preparation of TCSA cement clinkers were investigated by X-ray powder diffraction and scanning electron microscopy. The mechanical properties and hydration products of the cement pastes were also studied. The results indicated that the addition of CaF2, P2O5 and Na2O can promote the coexistence of ternesite and ye’elimite, and that Na2O is the most effective candidate. TCSA cement clinkers could be successfully prepared at 1150 °C for 30 min by doping 0.3% Na2O. The TCSA cement clinkers exhibited shorter setting times than the BCSA cement clinkers. The later strength of TCSA cement showed a significant increase compared with BCSA cement. The effect of Na2O was different on the strength development for TCSA and BCSA cement. The dissolution of ternesite could promote the formation of ettringite. The reactivity of belite was higher in TCSA cement due to the formation of strätlingite. Full article
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18 pages, 7020 KiB  
Article
Prediction of Abrasive Waterjet Machining Parameters of Military-Grade Armor Steel by Semi-Empirical and Regression Models
by Soundarapandian Rammohan, Sundaresan Thirumalai Kumaran, Marimuthu Uthayakumar, Kinga Korniejenko, Marek Nykiel and Arumugam Velayutham
Materials 2022, 15(12), 4368; https://doi.org/10.3390/ma15124368 - 20 Jun 2022
Cited by 4 | Viewed by 1761
Abstract
Rolled homogeneous armor steel (RHA) with a high tensile strength, toughness, and hardness is often used in military combat vehicles. RHA is a high-strength low alloy steel suitable for all battlefield usage in military vehicles. The present work examines the prediction output responses [...] Read more.
Rolled homogeneous armor steel (RHA) with a high tensile strength, toughness, and hardness is often used in military combat vehicles. RHA is a high-strength low alloy steel suitable for all battlefield usage in military vehicles. The present work examines the prediction output responses in the material removal rate (MRR), surface roughness (Ra), and kerf angle (Ka) for the AWJM of armor steel using regression and semi-empirical models. The AWJM trials were performed using an L27 factorial design with each process variable set to three levels, namely, the standoff distance (SOD), jet traversing speed (JT), and jet water pressure (P). A regression model was constructed using the response surface method (RSM) and data from the trials. Through dimensional analysis and with Buckingham’s π-theorem, a semi-empirical model was built using both the experimental data and material property data. Predictions made by the models were proportionate with the results of the experiments under the same conditions. Microscopic investigations on MRR and Ra were performed using a scanning electron microscope (SEM). The optimal values of the output responses of the machined armor steel plate were obtained with higher MRR = 298.92 mm3/min, lower Ka = 0.651°, and lower Ra = 2.23 µm. The present work established that semi-empirical models accurately predict the output responses in the AWJM of armor steel. Full article
(This article belongs to the Special Issue Materials Dedicated for Armours and Protection Systems)
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12 pages, 8639 KiB  
Article
Ultrasonic-Aided Co-Precipitation of Tannins and Chitosan Ammonium Salt on Cotton Fabric for Antimicrobial and Ultraviolet-Shielding Properties: An Efficient, Colourless, and Eco-Finishing Strategy
by Yuyang Zhou, Feiyang Zheng and Jingjing Wang
Materials 2022, 15(12), 4367; https://doi.org/10.3390/ma15124367 - 20 Jun 2022
Cited by 2 | Viewed by 1529
Abstract
Sustainable fabrication of protective cotton, using bio-extracts, is becoming increasingly attractive. However, many shortcomings—including the introduction of potentially hazardous mordants or modifiers to cotton, annoying colour changes after finishing, and low processing efficiency—require further melioration. Therefore, an efficient ultrasonic-assisted colourless finishing process was [...] Read more.
Sustainable fabrication of protective cotton, using bio-extracts, is becoming increasingly attractive. However, many shortcomings—including the introduction of potentially hazardous mordants or modifiers to cotton, annoying colour changes after finishing, and low processing efficiency—require further melioration. Therefore, an efficient ultrasonic-assisted colourless finishing process was developed in this study, to fabricate ultraviolet-proof and antimicrobial cotton. A pair of oppositely charged bio-based substances, i.e., tannin acid (TA) and hydroxypropyltrimethyl ammonium chloride chitosan (HACC) were introduced during the ultrasonic process. The results reveal that cationic HACC significantly promotes the adsorption of TA to cotton. The apparent colour of the cotton remained almost unchanged after finishing. Based on Pesudo first-/second-order kinetic models, chemisorption was verified as the dominant mechanism. Efficiency under ultrasound was enhanced by 5.3% (70 °C) and 27% (90 °C), respectively. A mathematical modelling study established the factors to be in the following order of significance: concentration > pH > temperature. Under optimal conditions, a theoretical maximum UPF of 380.8 was achieved. TA (8 g/L)-treated cotton deactivated up to 98% of Escherichia coli, and also provided excellent UV-shielding performance. In general, the ultrasonic-assisted eco-dyeing and finishing process for cotton was explored in depth from practical and theoretical perspectives, which should push forward the development of the sustainable textile industry. Full article
(This article belongs to the Special Issue Sustainable Colouration and Functional Finishing of Textiles)
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13 pages, 8421 KiB  
Article
Multiobjective Optimization of Cutting Parameters for TA10 Alloy Deep-Hole Drilling
by Yazhou Feng, Huan Zheng, Xiaolan Han and Zhanfeng Liu
Materials 2022, 15(12), 4366; https://doi.org/10.3390/ma15124366 - 20 Jun 2022
Cited by 2 | Viewed by 1628
Abstract
In order to obtain better quality TA10 pipes, the Boring and Trepanning Association (BTA) deep-hole drilling process is used. However, this type of machining leads to difficult chip removal, tool wear, and poor hole-surface quality. In this study, a deep-hole drilling experiment was [...] Read more.
In order to obtain better quality TA10 pipes, the Boring and Trepanning Association (BTA) deep-hole drilling process is used. However, this type of machining leads to difficult chip removal, tool wear, and poor hole-surface quality. In this study, a deep-hole drilling experiment was conducted on TA10 workpieces using the designed tool with different process parameters, and the process parameters were optimized by machining results with multiple objectives such as chip morphologies, tool wear, hole-axis deflection, and hole surface roughness. The results show that different process parameters have a great impact on the cutting process, with a higher feed resulting in smoother chip removal and a lower spindle speed resulting in lighter tool wear and less hole axis deflection. When the spindle speed is 145 r/min and the feed is 0.12 mm/r, the machined TA10 pipe meets both the accuracy requirement of roughness and the machining efficiency. Full article
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13 pages, 2230 KiB  
Article
Treatment of As(III)-Laden Contaminated Water Using Iron-Coated Carbon Fiber
by Dun Fu, Tonni Agustiono Kurniawan, Herong Gui, Songbao Feng, Qian Li and Mohd Hafiz Dzarfan Othman
Materials 2022, 15(12), 4365; https://doi.org/10.3390/ma15124365 - 20 Jun 2022
Cited by 28 | Viewed by 1736
Abstract
This work presents the fabrication, characterization, and application of iron-coated carbon fiber (Fe@CF), synthesized in a facile in situ iron reduction, for As(III) removal from an aqueous solution. The physico-chemical properties of the composite were characterized using Brunauer–Emmett–Teller (BET) surface area, scanning electron [...] Read more.
This work presents the fabrication, characterization, and application of iron-coated carbon fiber (Fe@CF), synthesized in a facile in situ iron reduction, for As(III) removal from an aqueous solution. The physico-chemical properties of the composite were characterized using Brunauer–Emmett–Teller (BET) surface area, scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier-transform infrared (FTIR) spectroscopy. Adsorption studies were evaluated in batch experiments with respect to reaction time, the dose of adsorbent, As(III) initial concentration, pH, and co-existing ions. The results showed that the BET surface area and pore volume of Fe@CF slightly decreased after Fe coating, while its pore size remained, while the SEM and XRD analyses demonstrated that the Fe was successfully anchored on the CF. A maximum As(III) adsorption of 95% was achieved with an initial As concentration of 1.5 mg/L at optimum conditions (30 min of reaction time, 1 g/L of dose, 1 mg/L of As(III) concentration, and pH 3.5). Since the treated effluents could not meet the strict discharge standard of ≤10 μg/L set by the World Health Organization (WHO), a longer reaction time is required to complete the removal of remaining As(III) in the wastewater effluents. As compared to the other adsorbents reported previously, the Fe@CF composite has the highest As(III) removal. Overall, the findings suggested that the use of Fe@CF as an adsorbent is promising for effective remediation in the aquatic environment. Full article
(This article belongs to the Special Issue Emerging Materials for Attaining Carbon Neutrality in Water Treatment)
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26 pages, 3746 KiB  
Article
About Inverse Laplace Transform of a Dynamic Viscosity Function
by Kamil Urbanowicz, Anton Bergant, Rafał Grzejda and Michał Stosiak
Materials 2022, 15(12), 4364; https://doi.org/10.3390/ma15124364 - 20 Jun 2022
Cited by 4 | Viewed by 1882
Abstract
A dynamic viscosity function plays an important role in water hammer modeling. It is responsible for dispersion and decay of pressure and velocity histories. In this paper, a novel method for inverse Laplace transform of this complicated function being the square root of [...] Read more.
A dynamic viscosity function plays an important role in water hammer modeling. It is responsible for dispersion and decay of pressure and velocity histories. In this paper, a novel method for inverse Laplace transform of this complicated function being the square root of the ratio of Bessel functions of zero and second order is presented. The obtained time domain solutions are dependent on infinite exponential series and Calogero–Ahmed summation formulas. Both of these functions are based on zeros of Bessel functions. An analytical inverse will help in the near future to derive a complete analytical solution of this unsolved mathematical problem concerning the water hammer phenomenon. One can next present a simplified approximate form of this solution. It will allow us to correctly simulate water hammer events in large ranges of water hammer number, e.g., in oil–hydraulic systems. A complete analytical solution is essential to prevent pipeline failures while still designing the pipe network, as well as to monitor sensitive sections of hydraulic systems on a continuous basis (e.g., against possible overpressures, cavitation, and leaks that may occur). The presented solution has a high mathematical value because the inverse Laplace transforms of square roots from the ratios of other Bessel functions can be found in a similar way. Full article
(This article belongs to the Special Issue Hydrodynamics in Materials Science: Experimental and Modeling)
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18 pages, 4392 KiB  
Article
Dielectric, AC Conductivity, and DC Conductivity Behaviours of Sr2CaTeO6 Double Perovskite
by Muhammad Zharfan Halizan and Zakiah Mohamed
Materials 2022, 15(12), 4363; https://doi.org/10.3390/ma15124363 - 20 Jun 2022
Cited by 10 | Viewed by 1717
Abstract
Relatively new double perovskite material, Sr2CaTeO6, has been prepared through conventional solid-state procedures. Structural, dielectric, and optical characteristics of this exquisite solid-state material were analysed in this study. The single-phase monoclinic P21/n structure of this prepared compound [...] Read more.
Relatively new double perovskite material, Sr2CaTeO6, has been prepared through conventional solid-state procedures. Structural, dielectric, and optical characteristics of this exquisite solid-state material were analysed in this study. The single-phase monoclinic P21/n structure of this prepared compound was well correlated with the literature review. Good distribution of grain sizes and shapes was observed in the morphological study of this compound. The discussions on its optical and dielectric properties are included in this manuscript. High dielectric real permittivity, low dielectric loss, and good capacitance over a range of temperatures possessed by this compound, as shown in dielectric and electrical modulus studies, indicated good potential values for capacitor applications. The Ro(RgQg)(RgbQgb) circuit fitted well with the impedance and electrical modulus plot of the compound. Its relatively high electrical DC conductivity in grain at high frequencies and its increasing value with the temperature are typical of a semiconductor behaviour. This behaviour might be attributed to the presence of minor oxygen vacancies within its lattice structure and provides a long-range conduction mechanism. A small difference between activation energy and Ea of DC conductivity indicates that the same charge carriers were involved in both grains and the grain boundaries’ long-range conduction. The electrical AC conductivity of this compound was found to contribute to the dielectric loss in grain structure and can be related to Jonscher’s power law. The presence of polarons in this compound was exhibited by non-overlapping small polaron tunnelling (NSPT) and overlapping large polaron tunnelling (OLPT) conduction mechanisms over a range of temperatures. Wide optical band gap and Eopt in the range of 2.6 eV to 3.6 eV were determined by using an indirect and direct allowed mechanism of electrons transitions. These values supported the efficient semiconducting behaviour of the grain in this material and are suitable for applications in the semiconductor industry. Full article
(This article belongs to the Special Issue Advanced Structures and Properties for Ceramic Materials)
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31 pages, 10504 KiB  
Review
A Comprehensive Review of Types, Properties, Treatment Methods and Application of Plant Fibers in Construction and Building Materials
by Muhammad Nasir Amin, Waqas Ahmad, Kaffayatullah Khan and Ayaz Ahmad
Materials 2022, 15(12), 4362; https://doi.org/10.3390/ma15124362 - 20 Jun 2022
Cited by 20 | Viewed by 5257
Abstract
Sustainable development involves the usage of alternative sustainable materials in order to sustain the excessive depletion of natural resources. Plant fibers, as a “green” material, are progressively gaining the attention of various researchers in the field of construction for their potential use in [...] Read more.
Sustainable development involves the usage of alternative sustainable materials in order to sustain the excessive depletion of natural resources. Plant fibers, as a “green” material, are progressively gaining the attention of various researchers in the field of construction for their potential use in composites for stepping towards sustainable development. This study aims to provide a scientometric review of the summarized background of plant fibers and their applications as construction and building materials. Studies from the past two decades are summarized. Quantitative assessment of research progress is made by using connections and maps between bibliometric data that are compiled for the analysis of plant fibers using Scopus. Data refinement techniques are also used. Plant fibers are potentially used to enhance the mechanical properties of a composite. It is revealed from the literature that plant-fiber-reinforced composites have comparable properties in comparison to composites reinforced with artificial/steel fibers for civil engineering applications, such as construction materials, bridge piers, canal linings, soil reinforcement, pavements, acoustic treatment, insulation materials, etc. However, the biodegradable nature of plant fibers is still a hindrance to their application as a structural material. For this purpose, different surface and chemical treatment methods have been proposed in past studies to improve their durability. It can be surmised from the gathered data that the compressive and flexural strengths of plant-fiber-reinforced cementitious composites are increased by up to 43% and 67%, respectively, with respect to a reference composite. In the literature, alkaline treatment has been reported as an effective and economical method for treating plant fibers. Environmental degradation due to excessive consumption of natural resources and fossil fuels for the construction industry, along with the burning of waste plant fibers, can be reduced by incorporating said fibers in cementitious composites to reduce landfill pollution and, ultimately, achieve sustainable development. Full article
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25 pages, 16274 KiB  
Article
An Experimentally Based Micromechanical Framework Exploring Effects of Void Shape on Macromechanical Properties
by Sara Eliasson, Mathilda Karlsson Hagnell, Per Wennhage and Zuheir Barsoum
Materials 2022, 15(12), 4361; https://doi.org/10.3390/ma15124361 - 20 Jun 2022
Cited by 5 | Viewed by 1819
Abstract
A micromechanical simulation approach in a Multi-Scale Modeling (MSM) framework with the ability to consider manufacturing defects is proposed. The study includes a case study where the framework is implemented exploring a cross-ply laminate. The proposed framework highlights the importance of correct input [...] Read more.
A micromechanical simulation approach in a Multi-Scale Modeling (MSM) framework with the ability to consider manufacturing defects is proposed. The study includes a case study where the framework is implemented exploring a cross-ply laminate. The proposed framework highlights the importance of correct input regarding micromechanical geometry and void characteristics. A Representative Volume Element (RVE) model is developed utilizing true micromechanical geometry extracted from micrographs. Voids, based on statistical experimental data, are implemented in the RVE model, and the effects on the fiber distribution and effective macromechanical properties are evaluated. The RVE algorithm is robust and maintains a good surrounding fiber distribution around the implemented void. The local void fraction, void size, and void shape affect the effective micromechanical properties, and it is important to consider the phenomena of the effective mechanical properties with regard to the overall void fraction of an RVE and the actual laminate. The proposed framework has a good prediction of the macromechanical properties and shows great potential to be used in an industrial implementation. For an industrial implementation, weak spots and critical areas for a laminate on a macro-level are found through combining local RVEs. Full article
(This article belongs to the Topic Composites in Aerospace and Mechanical Engineering)
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8 pages, 1854 KiB  
Article
Enhanced Energy Storage Properties of La-Doped Sr0.6Ba0.4Nb2O6 Relaxor Ferroelectric Ceramics Prepared by Spark Plasma Sintering
by Yingying Zhao, Xiao Liu, Xiaoyu Zhang and Huiling Du
Materials 2022, 15(12), 4360; https://doi.org/10.3390/ma15124360 - 20 Jun 2022
Cited by 3 | Viewed by 1386
Abstract
In this work, La-doped Sr0.6Ba0.4Nb2O6 ferroelectric ceramics were fabricated by the conventional solid state reaction method (CS) and spark plasma sintering (SPS), respectively. The microstructure, phase structure, dielectric properties, relaxor behavior, ferroelectric and energy storage properties [...] Read more.
In this work, La-doped Sr0.6Ba0.4Nb2O6 ferroelectric ceramics were fabricated by the conventional solid state reaction method (CS) and spark plasma sintering (SPS), respectively. The microstructure, phase structure, dielectric properties, relaxor behavior, ferroelectric and energy storage properties were investigated and compared to indicate the effects of spark plasma sintering on their performances. The results show that the grain shape changes from columnar to isometric crystal and the grain size decreases obviously after spark plasma sintering. The dielectric constant of the CS sample and the SPS sample both show a typical relaxor behavior with obvious frequency dispersion. The diffusion parameters (γ) of both CS sample and SPS sample are close to 2 and all the samples present slim polarization–electric (P-E) loops, which verify the relaxor behavior. Moreover, the breakdown strength, Eb, and discharge energy storage density, Wrec, of La-doped Sr0.6Ba0.4Nb2O6 ferroelectric ceramics prepared by SPS are improved significantly. This work provides guidance for improving the energy storage performance of ferroelectric ceramics with tungsten bronze structures by decreasing the grain size through adopting a different sintering method. Full article
(This article belongs to the Special Issue Preparation and Properties of Novel Energy Storage Materials)
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14 pages, 3558 KiB  
Article
Machine Learning Approaches for Monitoring of Tool Wear during Grey Cast-Iron Turning
by Maciej Tabaszewski, Paweł Twardowski, Martyna Wiciak-Pikuła, Natalia Znojkiewicz, Agata Felusiak-Czyryca and Jakub Czyżycki
Materials 2022, 15(12), 4359; https://doi.org/10.3390/ma15124359 - 20 Jun 2022
Cited by 10 | Viewed by 1965
Abstract
The dynamic development of new technologies enables the optimal computer technique choice to improve the required quality in today’s manufacturing industries. One of the methods of improving the determining process is machine learning. This paper compares different intelligent system methods to identify the [...] Read more.
The dynamic development of new technologies enables the optimal computer technique choice to improve the required quality in today’s manufacturing industries. One of the methods of improving the determining process is machine learning. This paper compares different intelligent system methods to identify the tool wear during the turning of gray cast-iron EN-GJL-250 using carbide cutting inserts. During these studies, the experimental investigation was conducted with three various cutting speeds vc (216, 314, and 433 m/min) and the exact value of depth of cut ap and federate f. Furthermore, based on the vibration acceleration signals, appropriate measures were developed that were correlated with the tool condition. In this work, machine learning methods were used to predict tool condition; therefore, two tool classes were proposed, namely usable and unsuitable, and tool corner wear VBc = 0.3 mm was assumed as a wear criterium. The diagnostic measures based on acceleration vibration signals were selected as input to the models. Additionally, the assessment of significant features in the division into usable and unsuitable class was caried out. Finally, this study evaluated chosen methods (classification and regression tree, induced fuzzy rules, and artificial neural network) and selected the most effective model. Full article
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13 pages, 7772 KiB  
Article
Investigation of Surface Micro-Mechanical Properties of Various Asphalt Binders Using AFM
by Yueqin Hou, Yun Chen, Haiwei Zou, Xiaoping Ji, Dongye Shao, Zhengming Zhang and Ye Chen
Materials 2022, 15(12), 4358; https://doi.org/10.3390/ma15124358 - 20 Jun 2022
Cited by 5 | Viewed by 1498
Abstract
The microstructure of asphalt affects the micro-mechanical properties. In this study, atomic force microscopy (AFM) was used to investigate the surface elastic modulus and nanohardness of asphalt binder. Relevant mechanical indexes were quantitatively evaluated by contact mechanical model. Five types of asphalts, including [...] Read more.
The microstructure of asphalt affects the micro-mechanical properties. In this study, atomic force microscopy (AFM) was used to investigate the surface elastic modulus and nanohardness of asphalt binder. Relevant mechanical indexes were quantitatively evaluated by contact mechanical model. Five types of asphalts, including different grades, oil sources, and before and after modification, were selected as test objects, and the effects of asphalt binder type, aging, water, and anti-stripping agent on the asphalt micromechanics were explored. The results showed that the micromechanical properties of asphalt binder are affected by grade, oil source, and modification. The aging resistance of modified asphalt binder is better than that of unmodified asphalt binder. Water immersion reduces the surface micromechanical properties of the asphalt binder. The effect of the anti-stripping agent on the modified asphalt binder is greater than that of the unmodified asphalt binder. Full article
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13 pages, 1499 KiB  
Article
Effect of Cooling Rate on Mechanical Properties, Translucency, Opalescence, and Light Transmission Properties of Monolithic 4Y-TZP during Glazing
by Ji-In Jeong, Hye-Jeong Shin, Yong Hoon Kwon and Hyo-Joung Seol
Materials 2022, 15(12), 4357; https://doi.org/10.3390/ma15124357 - 20 Jun 2022
Cited by 6 | Viewed by 1501
Abstract
A standard cooling rate has not been established for glazing; therefore, the effects of the cooling rate on the properties of zirconia need to be evaluated to predict outcomes in clinical practice. 4Y-TZP glazed at three different cooling rates was analyzed to estimate [...] Read more.
A standard cooling rate has not been established for glazing; therefore, the effects of the cooling rate on the properties of zirconia need to be evaluated to predict outcomes in clinical practice. 4Y-TZP glazed at three different cooling rates was analyzed to estimate the effect of cooling rate during glazing on the mechanical and optical properties. Hardness tests, field-emission scanning electron microscopy analysis, X-ray diffraction analysis, flexural strength measurement, and optical property evaluations were performed. When 4Y-TZP was glazed at a higher cooling rate (Cooling-1) than the normal cooling rate (Cooling-2), there was no significant difference in grain size, flexural strength, average transmittance, and translucency parameters. The hardness was slightly reduced. The opalescence parameter was reduced for the 2.03 mm thick specimens. When 4Y-TZP was glazed at a lower cooling rate (Cooling-3) than the normal cooling rate, there was no significant difference in hardness, grain size, flexural strength, and translucency parameters. In addition, the average transmittance and opalescence parameters were slightly reduced for the 0.52 and 2.03 mm specimens, respectively. The effects of the cooling rate during glazing on the mechanical and optical properties of 4Y-TZP appear to be minimal and clinically insignificant. Therefore, even if the cooling rate cannot be strictly controlled during glazing, the clinical outcomes will not be significantly affected. Full article
(This article belongs to the Special Issue Advances in Transparent Ceramics and Composites)
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20 pages, 5201 KiB  
Article
Experimental Study on Restoration Materials of Newly Earthen Ruins under Different Slaking Times
by Jianwei Yue, Wenhao Li, Xiang Zhu, Qingmei Kong, Xuanjia Huang, Xue Yang and Zhiguang Han
Materials 2022, 15(12), 4356; https://doi.org/10.3390/ma15124356 - 20 Jun 2022
Cited by 1 | Viewed by 1409
Abstract
The newly repaired Kaifeng City Wall has serious cracks, shedding and other issues on the surface, which constitute a significant problem. It is of great significance for the restoration of Kaifeng City Wall to explore the repair materials and techniques suitable for Kaifeng [...] Read more.
The newly repaired Kaifeng City Wall has serious cracks, shedding and other issues on the surface, which constitute a significant problem. It is of great significance for the restoration of Kaifeng City Wall to explore the repair materials and techniques suitable for Kaifeng City Wall. The pH, particle gradation, compressive strength and SEM were tested on soil samples with different lime and MgO contents under different slaking times. With the increase of slaking time, the pH value first increased and then decreased. The relationship between pH value and strength showed three stages. The strength of lime-containing soil samples increased first, then decreased and then increased. The MgO content of soil samples showed an opposite trend. The particle gradation was significantly improved with increasing aging time. The main reason for the reduction of soil strength is the calcium carbonate crystals and magnesite microcracks produced by lime and MgO in the later stage of slaking. Full article
(This article belongs to the Section Construction and Building Materials)
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17 pages, 8549 KiB  
Article
Optimisation on the Performance of Bubble-Bursting Atomisation for Minimum Quantity Lubrication with Vegetable Oil Using Computational Fluid Dynamics Simulation
by Pin Han Yap, Jaharah A. Ghani and Wan Mohd. Faizal Wan Mahmood
Materials 2022, 15(12), 4355; https://doi.org/10.3390/ma15124355 - 20 Jun 2022
Cited by 1 | Viewed by 1258
Abstract
Sustainable and green machining technologies have become a welcomed topic in the manufacturing industries. One of the emerging sustainable technologies is minimum quantity lubrication (MQL). In this study, the optimisation and study of the bubble-bursting atomisation system applied to MQL machining is carried [...] Read more.
Sustainable and green machining technologies have become a welcomed topic in the manufacturing industries. One of the emerging sustainable technologies is minimum quantity lubrication (MQL). In this study, the optimisation and study of the bubble-bursting atomisation system applied to MQL machining is carried out through the computational fluid dynamics (CFD) simulation approach. Vegetable oil is selected as the cooling lubricant in this study. The performance of the bubble-bursting atomisation system is improved by alternating air inlet velocity and the gap distance between the inlets of bubble production. A velocity of 0.1 ms−1 is suitable for the air at the inlets for the bubble production, whereas 10 ms−1 is suitable for the velocity of the air at the inlet, where the droplets of vegetable oil are guided to the nozzle. Besides that, a 50 mm gap distance between the air inlets for the production of bubbles is able to avoid the occurrence of bubble coalescence. Under these conditions, optimal bubble sizes of 2–3 mm can be achieved, with a higher probability of nano-sized droplets being present in these ranges. Furthermore, a higher rate and smaller size of vegetable oil droplets escaping the atomisation chamber and reaching the machining zone will be generated. Thus, the performance of the MQL machining can be improved. Full article
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17 pages, 6886 KiB  
Article
Methodology of Leakage Prediction in Gasketed Flange Joints at Pipeline Deformations
by Przemysław Jaszak, Janusz Skrzypacz, Andrzej Borawski and Rafał Grzejda
Materials 2022, 15(12), 4354; https://doi.org/10.3390/ma15124354 - 20 Jun 2022
Cited by 10 | Viewed by 1973
Abstract
The paper presents the proposal of a leakage prediction method in flange joints, after pipeline deformation, based on FEM (Finite Element Methods). The stages of developing the design are discussed, and a complex, multi-stage method of applying the loads is presented in detail. [...] Read more.
The paper presents the proposal of a leakage prediction method in flange joints, after pipeline deformation, based on FEM (Finite Element Methods). The stages of developing the design are discussed, and a complex, multi-stage method of applying the loads is presented in detail. Moreover, the gasket material data obtained in experiments were used. The paper also presents the results of calculations on a non-uniform stress distribution in the radial direction of the gasket. In addition, it has been shown that the deflection of the pipeline with a minor displacement causes an increase in the diversification of the circumferential pressure of the gasket, and also has a significant influence on the determination of the actual state of stress to which the gasket is subject. Moreover, it was found that the distribution of contact pressure on the deflection of the pipeline has a significant influence on the level of leakage. The results of tests are compared to the results of the numerical calculations of the stress in bolts. By comparing the bolt tension changes obtained by numerical and experiment analyses, it has been shown that the assumptions made in developing the numerical model are correct. Full article
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17 pages, 10980 KiB  
Article
Reinforcement Analysis of an Old Multi-Beam Box Girder Based on a New Embedded Steel Plate (ESP) Strengthening Method
by Yuliang He, Kai Wang, Zongyong Cao, Peijuan Zheng and Yiqiang Xiang
Materials 2022, 15(12), 4353; https://doi.org/10.3390/ma15124353 - 20 Jun 2022
Cited by 5 | Viewed by 1389
Abstract
Multi-beam box girder bridges have been applied widely throughout the world for many years. However, the cracking of longitudinal joints between the box girders always leads to reflective cracking of the bridge decks during the service period and thus finally affects the safety [...] Read more.
Multi-beam box girder bridges have been applied widely throughout the world for many years. However, the cracking of longitudinal joints between the box girders always leads to reflective cracking of the bridge decks during the service period and thus finally affects the safety and durability of the actual bridges. An embedded steel plate (ESP) strengthening method was presented by introducing carbon-A/-B glue to reinforce the longitudinal joints of old multi-beam box girder bridges for this problem. In order to evaluate the feasibility of the proposed method for actual bridges, an old multi-beam box girder bridge was reinforced, and structural parameters including strain, frequency, and deflection were obtained by adopting field tests before and after strengthening. In addition, the corresponding finite element (FE) model of the background bridge was also set up using ANASYS 18.0 to analyze the strengthening process. Analysis results of the actual bridge and FE model indicate that structural stiffness and load lateral transferring performance between the box girders were enhanced after ESP strengthening. Therefore, this proposed strengthening method can be used to improve the mechanical performance of multi-beam box girder bridges and provide reference for such bridge reinforcement. Full article
(This article belongs to the Special Issue Obtaining and Characterization of New Materials, Volume II)
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22 pages, 15167 KiB  
Article
The Influence of the Structure Parameters on the Mechanical Properties of Cylindrically Mapped Gyroid TPMS Fabricated by Selective Laser Melting with 316L Stainless Steel Powder
by Tomasz Szatkiewicz, Dorota Laskowska, Błażej Bałasz and Katarzyna Mitura
Materials 2022, 15(12), 4352; https://doi.org/10.3390/ma15124352 - 20 Jun 2022
Cited by 16 | Viewed by 2851
Abstract
The development of additive manufacturing techniques has made it possible to produce porous structures with complex geometry with unique properties as potential candidates for energy absorption, heat dissipation, biomedical, and vibration control application. Recently, there has been increased interest in additively manufacturing porous [...] Read more.
The development of additive manufacturing techniques has made it possible to produce porous structures with complex geometry with unique properties as potential candidates for energy absorption, heat dissipation, biomedical, and vibration control application. Recently, there has been increased interest in additively manufacturing porous structures based on triply periodic minimal surfaces (TPMS) topology. In this paper, the mechanical properties and energy absorption abilities of cylindrical mapped TPMS structures with shell gyroid unit cells fabricated by selective laser melting (SLM) with 316L stainless steel under compression loading were investigated. Based on the experimental study, it was found that tested structures exhibited two different deformation modes. There is also a relationship between the number and shapes of unit cells in the structure and the elastic modulus, yield strength, plateau stress, and energy absorption. These results can be used to design and manufacture more efficient lightweight parts lattices for energy absorbing applications, e.g., in the field of biomedical and bumpers applications. The deformation mode for each tested sample was also presented on the records obtained from the ARAMIS system. Full article
(This article belongs to the Collection Machining and Manufacturing of Alloys and Steels)
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17 pages, 8414 KiB  
Article
Microstructure and Phase Evolution of Ti-Al-C-Nb Composites Prepared by In Situ Selective Laser Forming
by Kai Zhang, Shurui Li, Zhilong Yan, Zhiwei Xiong, Desti Dorion Likoundayenda Bakoutas, Tingting Liu and Wenhe Liao
Materials 2022, 15(12), 4351; https://doi.org/10.3390/ma15124351 - 20 Jun 2022
Viewed by 1388
Abstract
In the present work, a novel Ti-Al-C-Nb composite was prepared using in situ selective laser forming (ISLF). The formation mechanism of the Ti-Al-C-Nb bulks, which were synthesized using elemental titanium, aluminum, and carbon (graphite) powders via ISLF techniques, was investigated. The results showed [...] Read more.
In the present work, a novel Ti-Al-C-Nb composite was prepared using in situ selective laser forming (ISLF). The formation mechanism of the Ti-Al-C-Nb bulks, which were synthesized using elemental titanium, aluminum, and carbon (graphite) powders via ISLF techniques, was investigated. The results showed that the Ti3Al and TiC phases were the dominant synthesis products during the chemical reactions, and these occurred during the ISLF process. The size of the fine nanoscale crystal TiC grains could reach 157 nm at an energy level of 60 J/mm3. The porous structure of the ISLF specimens was disclosed, and an open porosity of 20–44% was determined via the scanning speed and the laser power. Both the high dynamic viscosity and the reactions of the raw powders led to the generation of a considerable number of pores, whereas the specimen processed using 45 W and 100 mm/s possessed the lowest degree of open porosity. Full article
(This article belongs to the Section Manufacturing Processes and Systems)
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45 pages, 109102 KiB  
Article
Experimental Analysis of Steel Circular Hollow Section under Bending Loads: Comprehensive Study of Mechanical Performance
by Manahel Shahath Khalaf, Amer M. Ibrahim, Hadee Mohammed Najm, Mohanad Muayad Sabri Sabri, Samadhan Morkhade, Ashish Agarwal, Mohammed A. Alamir and Ibrahim M. Alarifi
Materials 2022, 15(12), 4350; https://doi.org/10.3390/ma15124350 - 20 Jun 2022
Cited by 1 | Viewed by 2322
Abstract
The present study aimed at evaluating the mechanical performance under bending loads of circular hollow sections of steel. Different bending tests have been carried out by applying two-point loads, to determine and examine the effects of the diameter, the thickness of the section, [...] Read more.
The present study aimed at evaluating the mechanical performance under bending loads of circular hollow sections of steel. Different bending tests have been carried out by applying two-point loads, to determine and examine the effects of the diameter, the thickness of the section, and the span of the beam on the performance of the steel tube. The effects of square opening and variation in the number of openings on the performance of these sections have also been examined. Ten samples of hollow circular beams of varying thickness (2 mm, 3 mm, and 6 mm), varying diameter (76.2 mm, 101.6 mm, and 219 mm), and varying span (1000 mm, 1500 mm, and 2000 mm) were fabricated and tested for pre-failure and post-failure stages. The dimensions of the reference specimen considered were 3 mm in thickness, 101.6 mm in diameter, and 1500 mm in span. The results have shown that on increasing the section thickness by 200%, ductility and bearing strength were enhanced by 58.04% and 81.75%, respectively. Meanwhile, decreasing the section thickness by 67%, ductility and bearing strength were reduced by 64.86% and 38.87%, respectively. Moreover, on increasing the specimen diameter and on decreasing span, a significant increase in bearing strength and stiffness was observed; however, ductility was reduced. Meanwhile, on increasing the span of the specimen, all the parameters observed, i.e., bearing strength, stiffness, and ductility, decreased. On observing the ultimate strength of each specimen with square opening, the ultimate strength was reduced by 17.88%, 19.71%, and 14.23% for one, two-, and three-square openings, respectively. Moreover, the ductility was significantly reduced by 72.40%, 67.71%, and 60.88% for one, two-, and three-square openings/apertures, respectively, and led to the sudden failure of these specimens. The local buckling failure dominated for specimens having a D/t ratio more than 50 and showed very negligible levels of ovalization of the cross-section. Local buckling failure was observed to be prevented after providing the circular rings in the specimen, since bearing strength increased compared with the specimen without rings. Full article
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17 pages, 2892 KiB  
Article
Development of an Oriented Co-Culture System Using 3D Scaffolds Fabricated via Non-Linear Lithography
by Antonis Kordas, Phanee Manganas, Alexandros Selimis, Georgios D. Barmparis, Maria Farsari and Anthi Ranella
Materials 2022, 15(12), 4349; https://doi.org/10.3390/ma15124349 - 20 Jun 2022
Cited by 2 | Viewed by 1554
Abstract
Damage in the Peripheral Nervous System (PNS) is related to numerous neurodegenerative diseases and has consequently drawn the attention of Tissue Engineering (TE), which is considered a promising alternative to already established methods such as surgery and autografts. TE focuses on the design, [...] Read more.
Damage in the Peripheral Nervous System (PNS) is related to numerous neurodegenerative diseases and has consequently drawn the attention of Tissue Engineering (TE), which is considered a promising alternative to already established methods such as surgery and autografts. TE focuses on the design, optimization, and use of scaffolds in vitro and in vivo. In this work, the authors used a novel scaffold geometry fabricated via Multiphoton Lithography (MPL), a commonly used fabrication method, for the mono- and co-cultures of glial Schwann (SW10) and neuronal Neuro-2a (N2a) cells. Both cell types have already been used for the study of various neurodegenerative diseases. However, their focus has been on only one of the cell types at a time, with studies regarding their co-culture only recently documented. Here, the suitability of the fabricated scaffolds has been explored and the effects of topography on SW10 and N2a behavior have been investigated. Our findings demonstrate that scaffold co-culture systems favor the presence of neurites compared to mono-cultures at 21 days (31.4 ± 5.5% and 15.4 ± 5.4%, respectively), while there is also a significant decrease in long neurites in the mono-culture over time (45.3 ± 15.9% at 7 days versus 15.4 ± 5.4% at 21 days). It has been shown that the scaffolds can successfully manipulate cell growth, elongation, and morphology, and these results can form a basis for the development of an experimental model for the study of PNS-related diseases and understanding of key cell functions such as myelination. Full article
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12 pages, 3599 KiB  
Article
Constitutive Model of the Surface Roughening Behavior of Austenitic Stainless Steel
by Abdul Aziz, Ming Yang, Tetsuhide Shimizu and Tsuyoshi Furushima
Materials 2022, 15(12), 4348; https://doi.org/10.3390/ma15124348 - 20 Jun 2022
Viewed by 1229
Abstract
The martensitic phase transformation (MPT) is one of the most important factors that enhances the surface roughening of stainless-steel thin metal foils (TMF), such as SUS 304, compared to others without MPT, even in the same plastic strain. However, the conventional roughening model [...] Read more.
The martensitic phase transformation (MPT) is one of the most important factors that enhances the surface roughening of stainless-steel thin metal foils (TMF), such as SUS 304, compared to others without MPT, even in the same plastic strain. However, the conventional roughening model does not take into account the influence of MPT. In this study, the authors proposed a new constitutive model to express the surface roughening by taking the influence of MPT into account. The volume fractions of MPT for TMF of SUS304 in various grain sizes are accounted for quantitatively after the tensile test at room temperature and an elevated temperature, and the effect of MPT on the surface roughening is evaluated in comparison to using TMF of SUS316, in which MPT does not occur during plastic deformation. Then, a constitutive model of the surface roughening based on the experimental results is successfully built. Full article
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13 pages, 1218 KiB  
Article
The Effect of Dentifrice on Micro-Hardness, Surface Gloss, and Micro-Roughness of Nano Filled Conventional and Bulk-Fill Polymer Composite—A Micro Indentation and Profilometric Study
by Mashael Binhasan, Abdulilah H. Solimanie, Khalid S. Almuammar, Ahmed R. Alnajres, Mai M. Alhamdan, Khold Al Ahdal, Yasser F. Alfaawaz, Khalid Ali, Fahim Vohra and Tariq Abduljabbar
Materials 2022, 15(12), 4347; https://doi.org/10.3390/ma15124347 - 20 Jun 2022
Cited by 3 | Viewed by 1469
Abstract
The aim of the present study was to evaluate the effect of brushing with two whitening dentifrices (Colgate Optic White (COW) and Colgate Optic White Charcoal (COC)) on surface gloss, micro-roughness, and micro-hardness of nanostructured hybrid conventional (Z350) and bulk-fill (Tetric N Ceram [...] Read more.
The aim of the present study was to evaluate the effect of brushing with two whitening dentifrices (Colgate Optic White (COW) and Colgate Optic White Charcoal (COC)) on surface gloss, micro-roughness, and micro-hardness of nanostructured hybrid conventional (Z350) and bulk-fill (Tetric N Ceram bulk-fill) polymer composite. In total, 96 disk samples using two nano-hybrid composite polymers (Z350 and Tetric N Ceram Bulk-fill) were prepared. All specimens were exposed to two different dentifrices (COW and COC), resulting in four main subgroups in the study. Specimens were assessed for surface gloss, micro-roughness (Ra), and micro-hardness using standardized methodology. Means and standard deviations of properties compared using paired t-test, one-way and two-way ANOVA, and post hoc test. The presence of dentifrices did not show any significant difference in micro-hardness values of Z350 (p > 0.05), whereas micro-hardness of bulk-fill composite significantly reduced on dentifrices exposure (p ≤ 0.05). Bulk-fill polymer composite showed significant reduction in gloss after dentifrice exposure (p < 0.05), however, Z350 showed no significant loss of gloss due to dentifrices (p > 0.05). A significant increase in Ra was observed for both resin materials after exposure to dentifrices (COC and COW). Conventional resin composite (Z350) showed comparable surface hardness and gloss before and after dentifrice exposure, however, micro-roughness increased significantly due to dentifrice exposure. Bulk-fill resin (Tetric N Ceram) showed significant loss of micro-hardness and gloss and increase in micro-roughness on dentifrice exposure. Conventional nano-hybrid composite polymer showed better durability in resisting loss of surface properties compared to bulk-fill resin polymer in the present experiment. Full article
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14 pages, 3730 KiB  
Article
Preparation of Wax-Based Warm Mixture Additives from Waste Polypropylene (PP) Plastic and Their Effects on the Properties of Modified Asphalt
by Gang Zhou, Chuanqiang Li, Haobo Wang, Wei Zeng, Tianqing Ling, Lin Jiang, Rukai Li, Qizheng Liu, Ying Cheng and Dan Zhou
Materials 2022, 15(12), 4346; https://doi.org/10.3390/ma15124346 - 20 Jun 2022
Cited by 4 | Viewed by 1915
Abstract
The production of high-performance, low-cost warm mix additives (WMa) for matrix asphalt remains a challenge. The pyrolysis method was employed to prepare wax-based WMa using waste polypropylene plastic (WPP) as the raw material in this study. Penetration, softening point, ductility, rotational viscosity, and [...] Read more.
The production of high-performance, low-cost warm mix additives (WMa) for matrix asphalt remains a challenge. The pyrolysis method was employed to prepare wax-based WMa using waste polypropylene plastic (WPP) as the raw material in this study. Penetration, softening point, ductility, rotational viscosity, and dynamic shear rheological tests were performed to determine the physical and rheological properties of the modified asphalt. The adhesion properties were characterized using the surface free energy (SFE) method. We proved that the pyrolysis temperature and pressure play a synergistic role in the production of wax-based WMa from WPPs. The product prepared at 380 °C and 1.0 MPa (380-1.0) can improve the penetration of matrix asphalt by 61% and reduce the viscosity (135 °C) of matrix asphalt by 48.6%. Furthermore, the modified asphalt shows favorable elasticity, rutting resistance, and adhesion properties; thus, it serves as a promising WMa for asphalt binders. Full article
(This article belongs to the Special Issue Performance-Related Material Properties of Asphalt Mixture Components)
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13 pages, 8051 KiB  
Article
Predictions and Experiments on the Distortion of the 20Cr2Ni4A C-ring during Carburizing and Quenching Process
by Yongming Yan, Yanjun Xue, Wenchao Yu, Ke Liu, Maoqiu Wang, Xinming Wang and Liuqing Ni
Materials 2022, 15(12), 4345; https://doi.org/10.3390/ma15124345 - 20 Jun 2022
Cited by 1 | Viewed by 1559
Abstract
This paper focuses on the effect of gear steel on distortion due to phase transformation in carburizing and quenching. The carburizing and quenching process of C-rings under suspension was studied by using the finite element method based on the thermo-mechanical theory, considering phase [...] Read more.
This paper focuses on the effect of gear steel on distortion due to phase transformation in carburizing and quenching. The carburizing and quenching process of C-rings under suspension was studied by using the finite element method based on the thermo-mechanical theory, considering phase transformation. The phase transformation kinetics parameters, depending on different carbon contents, were measured by Gleeble-3500. The distortion behavior of the carburized C-ring during the cooling stage was analyzed, as well as the carbon concentration distribution and martensite volume fractions. The accuracy of the simulation was also verified by comparing the experimental data with the simulated result of the distortion and microstructure. A reliable basis is provided for predicting the distortion mechanism of gear steels in carburizing and quenching. Full article
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15 pages, 6530 KiB  
Article
Preparation and Hydration of Brownmillerite-Belite-Sulfoaluminate Cement
by Xuemei Chen, Jun Li, Zhongyuan Lu, Yunhui Niu, Jun Jiang, Yigang Xu and Wen Zhong
Materials 2022, 15(12), 4344; https://doi.org/10.3390/ma15124344 - 20 Jun 2022
Cited by 2 | Viewed by 1493
Abstract
Brownmillerite-belite-sulfoaluminate clinker with different contents of brownmillerite were designed and successfully prepared by using limestone (LS), aluminum tailings (AT), aluminum mine (AM), and anhydrite (AH) calcined at 1330 °C for 30 min. Then, three kinds of brownmillerite-belite-sulfoaluminate cement (BBSC) were obtained by grinding [...] Read more.
Brownmillerite-belite-sulfoaluminate clinker with different contents of brownmillerite were designed and successfully prepared by using limestone (LS), aluminum tailings (AT), aluminum mine (AM), and anhydrite (AH) calcined at 1330 °C for 30 min. Then, three kinds of brownmillerite-belite-sulfoaluminate cement (BBSC) were obtained by grinding mixtures of the clinker and AH. Hydration and mechanical performances of the prepared BBSC were thus intensively studied. The increase in brownmillerite in BBSC decreased the hydration exothermic rate and delayed the renewed rapid formation of AFt at early hydration stages. However, the formation of C2AS·8H2O would be promoted, where the higher the brownmillerite content in BBSC, the earlier the C2AS·8H2O formed. The increase in brownmillerite might change the morphologies of the formed AFt, grass-shaped AFt enriched in iron would be the main hydration products in BBSC with a higher content of brownmillerite. The increase in brownmillerite content contributed to the stability improvement in flexural strength and the stable growth in the compressive strength of BBSC. The appropriate content of brownmillerite (20 wt%) can balance the whole hydration reaction process, which was conducive to the development of BBSC mechanical strength, the decrease in the hydration heat release, and the volume stability of hardened pastes. Full article
(This article belongs to the Section Construction and Building Materials)
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19 pages, 12194 KiB  
Article
The Influence of Heat Treatment on the Mechanical Properties and Corrosion Resistance of the Ultrafine-Grained AA7075 Obtained by Hydrostatic Extrusion
by Marta Orłowska, Ewa Ura-Bińczyk, Lucjan Śnieżek, Paweł Skudniewski, Mariusz Kulczyk, Bogusława Adamczyk-Cieślak and Kamil Majchrowicz
Materials 2022, 15(12), 4343; https://doi.org/10.3390/ma15124343 - 20 Jun 2022
Cited by 8 | Viewed by 1560
Abstract
In this paper, the corrosion resistance and mechanical properties of the 7075 aluminum alloy are studied. The alloy was deformed by hydrostatic extrusion and then aged both naturally and artificially. Results are compared with those of coarse-grained material subjected to T6 heat treatment. [...] Read more.
In this paper, the corrosion resistance and mechanical properties of the 7075 aluminum alloy are studied. The alloy was deformed by hydrostatic extrusion and then aged both naturally and artificially. Results are compared with those of coarse-grained material subjected to T6 heat treatment. The aim of the research is to find the optimal correlation between the mechanical properties and the corrosion resistance of the alloy. To this end, static tensile tests with subsequent fractography, open circuit potential, and potentiodynamic polarization tests in 0.05 M NaCl were conducted. Obtained results show that a combination of precipitate hardening and a deformed microstructure leads to increased mechanical strength with high anisotropy due to the presence of fibrous grains. Plastic deformation increases susceptibility to corrosion due to the increased number of grain boundaries, which act as paths along that corrosion propagates. However, further artificial aging incurs a positive effect on corrosion resistance due to changes in the chemical composition of the matrix as a result of the precipitation process. Full article
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33 pages, 12843 KiB  
Article
Design and Finite Element Analysis of Patient-Specific Total Temporomandibular Joint Implants
by Shirish M. Ingawale and Tarun Goswami
Materials 2022, 15(12), 4342; https://doi.org/10.3390/ma15124342 - 20 Jun 2022
Cited by 4 | Viewed by 2056
Abstract
In this manuscript, we discuss our approach to developing novel patient-specific total TMJ prostheses. Our unique patient-fitted designs based on medical images of the patient’s TMJ offer accurate anatomical fit, and better fixation to host bone. Special features of the prostheses have potential [...] Read more.
In this manuscript, we discuss our approach to developing novel patient-specific total TMJ prostheses. Our unique patient-fitted designs based on medical images of the patient’s TMJ offer accurate anatomical fit, and better fixation to host bone. Special features of the prostheses have potential to offer improved osseo-integration and durability of the devices. The design process is based on surgeon’s requirements, feedback, and pre-surgical planning to ensure anatomically accurate and clinically viable device design. We use the validated methodology of FE modeling and analysis to evaluate the device design by investigating stress and strain profiles under functional/normal and para-functional/worst-case TMJ loading scenarios. Full article
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10 pages, 2182 KiB  
Article
Influence of Alkaline Earth Metals on Structure Formation and Magnesium Alloy Properties
by Vadym Shalomeev, Galyna Tabunshchyk, Viktor Greshta, Marek Nykiel and Kinga Korniejenko
Materials 2022, 15(12), 4341; https://doi.org/10.3390/ma15124341 - 20 Jun 2022
Cited by 3 | Viewed by 1409
Abstract
The main aim of this work is to improve the structure and properties of the magnesium alloy ML5 by modifying it with alkaline earth metals (ALM). The separate and joint influence of calcium and barium on the macrostructure and microstructure of the alloy [...] Read more.
The main aim of this work is to improve the structure and properties of the magnesium alloy ML5 by modifying it with alkaline earth metals (ALM). The separate and joint influence of calcium and barium on the macrostructure and microstructure of the alloy of Mg-Al-Zn system was investigated. The qualitative and quantitative estimation of the structural components was carried out. Alkali earth metals were included in complex intermetallic phases and serve as additional crystallization centers. Modification of magnesium alloys with alkaline earth metals is established in an amount of 0.05 to 0.1 wt. % increased the bulk percentage of intermetallic phases by ~1.5 times, shifting them towards smaller size groups while simultaneously forming spherical intermetallic phases located in the grain centre and serving as additional crystallization centers. In this case, grain size reduction and significant refinement of the alloy structural components were provided. The dependency of the separate and joint influence of alkali earth metals on the castings complex of properties of the magnesium alloy has been established. Thus, a separate modification of the ML5 alloy provided the maximum level of its strength and ductility with the addition of 0.1% Ca or Ba. The modification of the complex (0.1% Ca + 0.1% Ba) of the magnesium alloy decreased the dimensions of its structural components 1.5 times and increased the strength of the alloy by 20%, the ductility by 2 times and the long-term heat resistance 1.5 times due to the formation of the intermetallic phases of the complex composition. Linear dependences were obtained that describe the influence of the characteristics of the structural components of the modified magnesium alloy on its mechanical properties. The developed technology for modifying cast magnesium alloys with alkaline earth elements provides an improvement in casting quality and allows the reliability and durability of responsible casting operation. Full article
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13 pages, 6182 KiB  
Article
Effect of Sulfur Content in Sulfate-Rich Copper Tailings on the Properties of MgO-Activated Slag Materials
by Peiyuan Chen, Fan Yang, Xin Qian, Yi Fang, Jin Li, Xueyan Chen and Yonghui Wang
Materials 2022, 15(12), 4340; https://doi.org/10.3390/ma15124340 - 20 Jun 2022
Cited by 2 | Viewed by 1449
Abstract
The high-value utilization of sulfate-rich tailings (SRCTs) can accelerate their mass consumption, so the many problems caused by the massive accumulation of SRCTs can be alleviated, such as environmental pollution, land occupation, security risk, etc. This study proposes using SRCTs to replace fine [...] Read more.
The high-value utilization of sulfate-rich tailings (SRCTs) can accelerate their mass consumption, so the many problems caused by the massive accumulation of SRCTs can be alleviated, such as environmental pollution, land occupation, security risk, etc. This study proposes using SRCTs to replace fine natural aggregates in MgO-activated slag materials (MASMs) and investigate the influence of the sulfur content in SRCTs on the properties of MASMs. The experimental results showed that the 28 d compressive strength of MASM mortars was increased by up to 83% using SRCT composites. Two major mechanisms were discovered: additional hydration product formation and pore structure refinement. The results of XRD suggested that incorporating SRCT composite into MASMs increased the production of expansive sulfate-containing hydration products, such as ettringite, gypsum, and hydroxyl-Afm. The results of element mapping showed that the oxidation of pyrite in SRCTs could release sulfates into the surrounding area and participate in the hydration of MASM, indicating that SRCTs can work as an auxiliary activator for MASMs. Furthermore, the addition of SRCT significantly refined the pore structure of MASMs, leading to the reduction in porosity by up to 37.77%. These findings confirm a synergistic effect on activating the slag between SRCTs and MgO, promoting the mass utilization of SRCTs. As a result, the additional expansive hydration products contribute to the enhanced compressive strength and refined pore structure. Full article
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