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Crystals, Volume 12, Issue 6 (June 2022) – 127 articles

Cover Story (view full-size image): In the 1960s, a worldwide change in electronic devices was about to occur with the invention of integrated circuits. The chip was upon us, which instantly created the need for a revolution in visual communication displays. In the UK, a curious combination of government research facilities, electronic companies, and one small university came together in 1970 to form a consortium, and within two years, the basis for new technologies had been founded. View this paper
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21 pages, 3897 KiB  
Article
Thermodynamic Properties of 1,5-Pentanediamine Adipate Dihydrate in Three Binary Solvent Systems from 278.15 K to 313.15 K
by Liang Li, Yihan Zhao, Baohong Hou, Han Feng, Na Wang, Dong Liu, Yingjie Ma, Ting Wang and Hongxun Hao
Crystals 2022, 12(6), 877; https://doi.org/10.3390/cryst12060877 - 20 Jun 2022
Cited by 1 | Viewed by 1337
Abstract
In this work, solubility data of 1,5-pentanediamine adipate dihydrate in binary solvent systems of water + methanol, water + ethanol and water + N,N-dimethylformamide were experimentally measured via a static gravimetric method in the temperature range from 278.15 K to 313.15 K under [...] Read more.
In this work, solubility data of 1,5-pentanediamine adipate dihydrate in binary solvent systems of water + methanol, water + ethanol and water + N,N-dimethylformamide were experimentally measured via a static gravimetric method in the temperature range from 278.15 K to 313.15 K under atmospheric pressure. The results indicated that the solubility of 1,5-pentanediamine adipate dihydrate increased with the rising of temperature in all the selected binary solvent systems. For water + N,N-dimethylformamide, solubility increased as the mole fraction of water increased. However, the rising tendency changed when the temperature was higher than 303.15 K for water + methanol, and it would show a cosolvency phenomenon for water + ethanol. Furthermore, the solubility data were fitted with modified an Apelblat equation, NRTL model, combined nearly ideal binary solvent/Redlich Kister (CNIBS/R-K) model and Jouban–Acree model. The calculation results agreed well with the experimental data. Finally, the mixing thermodynamic properties of 1,5-pentanediamine adipate dihydrate in all tested solvents were calculated based on the experimental data and NRTL model. Full article
(This article belongs to the Special Issue Polymorphism in Crystals)
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10 pages, 1444 KiB  
Communication
Theoretical Investigation of Magneto-Electro-Elastic Piezoelectric Phononic Crystal
by Wen-Chao Bai, Yan Cao, Ben-Hu Zhou, Jian-Lin Liu, Gui-Xiang Liu, Han Zhang, Han-Zhuang Zhang and Hui Hu
Crystals 2022, 12(6), 876; https://doi.org/10.3390/cryst12060876 - 20 Jun 2022
Viewed by 1520
Abstract
We design a magneto-electro-elastic piezoelectric phononic crystal (MPPC) using a one-dimensional piezoelectric superlattice (with a 3m point group) and split-ring resonators. The effect of the split-ring resonators is to enhance the piezoelectric effect of the piezoelectric superlattices. This effect will create elastic anomalies [...] Read more.
We design a magneto-electro-elastic piezoelectric phononic crystal (MPPC) using a one-dimensional piezoelectric superlattice (with a 3m point group) and split-ring resonators. The effect of the split-ring resonators is to enhance the piezoelectric effect of the piezoelectric superlattices. This effect will create elastic anomalies and generate the phononic band gaps. These are first proposed theoretically. We calculate the transmission function of the MPPC through Transfer Matrix Method of the phononic crystal. By using the transmission function, we theoretically study the propagation properties of the acoustic waves in the MPPC. The mechanism for multifield coupling is analyzed. A type of phononic band gap is created, called the multifield coupling phononic band gap. We analyze the possibility of crystals as left-handed metamaterials. We also discuss some potential applications. Full article
(This article belongs to the Special Issue Active, Tunable and Reconfigurable Elastic Metamaterials)
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12 pages, 6324 KiB  
Article
Powder Extrusion Printing and Sintering Densification Behaviors of Ultrafine 98W-1Ni-1Fe Alloy Powder
by Yong Han, Xiao Wu, Xue Jiang and Yihan Yang
Crystals 2022, 12(6), 875; https://doi.org/10.3390/cryst12060875 - 20 Jun 2022
Cited by 1 | Viewed by 1198
Abstract
Powder extrusion printing (PEP) is an attractive fabrication technique for the automated mass production of engineering components with complicated shape and high-dimensional accuracy. This paper is concerned with PEP and sintering densification of ultrafine 98W-1Ni-1Fe powder. Three kinds of binder systems were designed. [...] Read more.
Powder extrusion printing (PEP) is an attractive fabrication technique for the automated mass production of engineering components with complicated shape and high-dimensional accuracy. This paper is concerned with PEP and sintering densification of ultrafine 98W-1Ni-1Fe powder. Three kinds of binder systems were designed. The influence of binder composition on the rheological behavior of the PEP feedstocks has been investigated. Results showed that all the feedstocks present pseudoplastic flow behavior. Compared with the FS-55 and FS-70 feedstocks, the FS-65 feedstock is more suitable for the PEP of ultrafine 98W-1Ni-1Fe powder due to its better comprehensive rheology and more homogeneous microstructure. The PEPed ultrafine 98W-1Ni-1Fe can be sintered to near full density at 1420 °C, which is much lower than traditional micro-scaled powder. The sintered 98W-1Ni-1Fe shows good mechanical performance due to its fine and uniform microstructure, its tensile strength can reach ~800 MPa, and its grain size is about 15 μm. Full article
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19 pages, 8220 KiB  
Article
Trimetallic Oxides/GO Composites Optimized with Carbon Ions Radiations for Supercapacitive Electrodes
by Adil Alshoaibi, Chawki Awada, Faheem Ahmed, Raphael M. Obodo, Malik Maaza and Fabian I. Ezema
Crystals 2022, 12(6), 874; https://doi.org/10.3390/cryst12060874 - 20 Jun 2022
Cited by 3 | Viewed by 1600
Abstract
Hydrothermally synthesized electrodes of Co3O4@MnO2@NiO/GO were produced for use in supercapacitors. Graphene oxide (GO) was incorporated into the nanocomposites used for electrode synthesis due to its great surface area and electrical conductivity. The synergistic alliance among these [...] Read more.
Hydrothermally synthesized electrodes of Co3O4@MnO2@NiO/GO were produced for use in supercapacitors. Graphene oxide (GO) was incorporated into the nanocomposites used for electrode synthesis due to its great surface area and electrical conductivity. The synergistic alliance among these composites and GO enhances electrode performance, life span, and stability. The structural properties obtained from the X-ray diffraction (XRD) results suggest that nanocomposites are crystalline in nature. The synergistic alliance among these composites and GO enhances electrode performance, life span, and stability. Performance assessment of these electrodes indicates that their characteristic performance was enhanced by C2+ radiation, with the uttermost performance witnessed for electrodes radiated with 5.0 × 1015 ions/cm2. Full article
(This article belongs to the Special Issue New Trends in Crystals at Saudi Arabia (Volume II))
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18 pages, 10956 KiB  
Article
Numerical Simulation of Molten Pool Dynamics in Laser Deep Penetration Welding of Aluminum Alloys
by Jin Peng, Hongqiao Xu, Xiaohong Yang, Xingxing Wang, Shuai Li, Weimin Long and Jian Zhang
Crystals 2022, 12(6), 873; https://doi.org/10.3390/cryst12060873 - 20 Jun 2022
Cited by 2 | Viewed by 1780
Abstract
In this paper, the numerical simulation of molten pool dynamics in laser deep penetration welding of aluminum alloys was established based on the FLUENT 19.0 software. The three-dimensional transient behavior of the keyhole and the flow field of molten pool at different welding [...] Read more.
In this paper, the numerical simulation of molten pool dynamics in laser deep penetration welding of aluminum alloys was established based on the FLUENT 19.0 software. The three-dimensional transient behavior of the keyhole and the flow field of molten pool at different welding speeds were analyzed, and the influence of the welding speed on the molten pool of aluminum alloys in laser welding was obtained. The results indicated that the generation of welding spatters was directly related to the fluctuation of the diameter size in the middle of the keyhole. When the diameter in the middle of the keyhole increased by a certain extent, welding spatters occurred. When welding spatters occurred, the diameter in the middle of the keyhole became smaller. In addition, the size of the spatters at the welding speed of 9 m/min was larger than that of the spatters at the welding speeds of 3 m/min and 6 m/min. The welding spatter formed in laser deep penetration welding included: spatter created by an inclined liquid column behind the keyhole; splash created by a vertical liquid column behind the keyhole; small particles splashed in front of the keyhole. With the increase of the welding speed, the tendency of the welding spatter to form in front of the keyhole and to form a vertical liquid column behind the keyhole became weaker. When the welding speed was 9 min, only an obliquely upward liquid column appeared on the molten pool surface behind the keyhole. Compared with the welding speeds of 6 m/min and 9 m/min, the maximum flow velocity fluctuation of the molten pool at the welding speed of 3 m/min was obviously higher. Full article
(This article belongs to the Special Issue Laser Melting of Metals and Metal Matrix Composites)
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16 pages, 6589 KiB  
Article
Multi-Component Diffusion in the Vicinity of a Growing Crystal
by Christoph Helfenritter and Matthias Kind
Crystals 2022, 12(6), 872; https://doi.org/10.3390/cryst12060872 - 20 Jun 2022
Cited by 2 | Viewed by 1344
Abstract
Co-crystallization from multi-component solutions occurs in many solids formation processes. The measurement or simulative description of concentration courses in the fluid vicinity of a growing crystalline substrate is difficult for such systems. These are relevant with respect to developing concentrations of crystallizing components [...] Read more.
Co-crystallization from multi-component solutions occurs in many solids formation processes. The measurement or simulative description of concentration courses in the fluid vicinity of a growing crystalline substrate is difficult for such systems. These are relevant with respect to developing concentrations of crystallizing components at the solid-liquid interface due to diffusion fluxes in the solution. Concentrations may change such that unintended crystalline states can develop. With Fickian multi-component diffusion modeling we are able to simulate the timely evolution of the concentrations in the diffusion boundary layer during crystallization of various solid entities. Not only single solvate crystallization is modeled but also co-crystallization from multi-component solutions with different solvate states. The simulations are run with the assumption that diffusion limitation dominates. However, the model can be easily adapted to integration limitation. The interdependence of two diffusing components is taken into account in Fick’s multicomponent diffusion with a diffusion coefficient between these two components. We show that the consideration of so called cross-diffusion effects between dissolved materials can be neglected during crystallization of single decahydrates and during co-crystallization of anhydrous electrolytes. The presented model is also capable of fitting crystal growth kinetics with single point desupersaturation measurements in a thin film. In addition to the study of the kinetic parameters, the simulation allows the determination of the spatial concentration evolution from the single point concentration measurements. Full article
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15 pages, 3152 KiB  
Article
Behavior of B- and Z-DNA Crystals under High Hydrostatic Pressure
by Thierry Prangé, Nathalie Colloc’h, Anne-Claire Dhaussy, Marc Lecouvey, Evelyne Migianu-Griffoni and Eric Girard
Crystals 2022, 12(6), 871; https://doi.org/10.3390/cryst12060871 - 20 Jun 2022
Cited by 2 | Viewed by 1806
Abstract
Single crystals of B-DNA and Z-DNA oligomers were analyzed under high hydrostatic pressure and their behavior was compared to the A-DNA crystals already known. The amplitude of the base compression, when compared to the A-form of DNA (0.13 Å/GPa), was higher for the [...] Read more.
Single crystals of B-DNA and Z-DNA oligomers were analyzed under high hydrostatic pressure and their behavior was compared to the A-DNA crystals already known. The amplitude of the base compression, when compared to the A-form of DNA (0.13 Å/GPa), was higher for the Z-DNA (0.32 Å/GPa) and was the highest for the B-DNA (0.42 Å/GPa). The B-DNA crystal degraded rapidly around 400–500 MPa, while the Z-structure was more resistant, up to 1.2 GPa. Full article
(This article belongs to the Special Issue Crystalline Phases under Extreme Conditions)
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12 pages, 1392 KiB  
Article
Computational Studies of the Excitonic and Optical Properties of Armchair SWCNT and SWBNNT for Optoelectronics Applications
by Yahaya Saadu Itas, Abdussalam Balarabe Suleiman, Chifu E. Ndikilar, Abdullahi Lawal, Razif Razali, Ismail Ibrahim Idowu, Mayeen Uddin Khandaker, Pervaiz Ahmad, Nissren Tamam, Abdelmoneim Sulieman and Mohammad Rashed Iqbal Faruque
Crystals 2022, 12(6), 870; https://doi.org/10.3390/cryst12060870 - 20 Jun 2022
Cited by 15 | Viewed by 1497
Abstract
In this study, the optical refractive constants of the (5, 5) SWBNNT and (5, 5) SWCNT systems were calculated in both parallel and perpendicular directions of the tube axis by using Quantum ESPRESSO and YAMBO code. It also extended the optical behaviors of [...] Read more.
In this study, the optical refractive constants of the (5, 5) SWBNNT and (5, 5) SWCNT systems were calculated in both parallel and perpendicular directions of the tube axis by using Quantum ESPRESSO and YAMBO code. It also extended the optical behaviors of (5, 5) SWCNT and (5, 5) SWBNNT to both perpendicular and parallel directions instead of the parallel directions reported in the literature. It also looked at the effects of the diameter of the nanotube on the optical properties instead of chiral angles. From our results, the best optical reflection was found for (5, 5) SWBNNT, while the best optical refraction was found with (5, 5) SWCNT. It was observed that the SWCNT demonstrates refraction in both parallel and perpendicular directions, while (5, 5) SWBNNT shows perfect absorption in perpendicular direction. These new features that appeared for both nanotubes in perpendicular directions were due to new optical band gaps, which appear in the perpendicular directions to both nanotubes’ axis. The electron energy loss (EEL) spectrum of SWBNNT revealed the prominent π- and π + δ- Plasmon peaks, which demonstrates themselves in the reflectivity spectrum. Furthermore, little effect of diameter was observed for the perpendicular direction to both nanotubes’ axis; as such, the combined properties of (5, 5) SWBNNT and (5, 5) SWCNT materials/systems for transmitting light offer great potential for applications in mobile phone touch screens and mobile network antennas. In addition, the studies of optical properties in the perpendicular axis will help bring ultra-small nanotubes such as SWCNT and SWBNNT to the applications of next-generation nanotechnology. Full article
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18 pages, 6518 KiB  
Article
Growth and Characterization of Second and Third Order Acentric Studies of l-Phenylalanine l-Phenylalaninium Malonate Single Crystal
by P. Sangeetha, M. Nageshwari, C. Rathika Thaya Kumari, S. Srividhya, G. Vinitha, G. Mathubala, A. Manikandan, M. Lydia Caroline, Anish Khan, Hajer S. Alorfi, Mahmoud Ali Hussein and Madhu Puttegowda
Crystals 2022, 12(6), 869; https://doi.org/10.3390/cryst12060869 - 20 Jun 2022
Cited by 4 | Viewed by 1640
Abstract
A single crystal of l-phenylalanine l-phenylalanininum malonate (LPPMA) was synthesized by slow evaporation and was subjected to nonlinear optical examination and physio-chemical characterization. Studies on single X-ray diffraction confirm the arrangement of monoclinic space group P21 which is a vital criterion [...] Read more.
A single crystal of l-phenylalanine l-phenylalanininum malonate (LPPMA) was synthesized by slow evaporation and was subjected to nonlinear optical examination and physio-chemical characterization. Studies on single X-ray diffraction confirm the arrangement of monoclinic space group P21 which is a vital criterion for the NLO phenomenon. The assessment of functional groups and diverse vibration modes responsible for the characteristics of the material was performed with an FTIR analysis. The UV-visible spectral examination found the wavelength of UV-cutoff at 233 nm and various optical parameters were evaluated. The mechanical strength and different criteria associated with it were assessed. The electric field response of the material was examined in terms of the dielectric constant, dielectric loss, ac conductivity and activation energy. The spectra of emission were detailed. The efficacy of second harmonic generation was studied. The parameters of nonlinearity were investigated to analyse the third-order acentric optical response in the LPPMA by Z-scan procedure. Full article
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19 pages, 7156 KiB  
Article
Experimental Studies on Mechanical Properties and Microscopic Mechanism of Marble Waste Powder Cement Cementitious Materials
by Tongkuai Wang, Wenwei Yang and Jintuan Zhang
Crystals 2022, 12(6), 868; https://doi.org/10.3390/cryst12060868 - 19 Jun 2022
Cited by 6 | Viewed by 1545
Abstract
The resource utilization of waste stone powder is a meaningful way to realize sustainable development. This paper aims to study the influence of marble waste powder particle size and replacement cement dosage on the mechanical properties of cementitious materials and evaluate its microstructure [...] Read more.
The resource utilization of waste stone powder is a meaningful way to realize sustainable development. This paper aims to study the influence of marble waste powder particle size and replacement cement dosage on the mechanical properties of cementitious materials and evaluate its microstructure and mineral characterization by SEM and XRD. The results show that the early strength of cementitious materials is obviously improved when the dosage of marble waste powder is in the range of 0–15%, and the lifting effect of marble waste powder with a particle size of 600 mesh instead of cement on the strength and microstructure of cementitious materials is the most obvious. The replacement of cement with different particle sizes of marble waste powder found that it had low chemical activity and participated in the hydration reaction of cement, but the reaction degree was low. The smaller the particle size of marble waste powder instead of cement, the denser the early microstructure, the more obvious the nucleation phenomenon, and the more serious the agglomeration between particles. In addition, the mechanism model of marble waste powder replacing cement cementitious materials was proposed. The strength prediction function model between the material dosage and compressive strength was constructed, and the accuracy of the model was verified. Full article
(This article belongs to the Special Issue Geopolymer Composites)
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15 pages, 6618 KiB  
Article
A Numerical Simulation and Experimental Study on the Ultrafast Double-Laser Precision Cutting of Sapphire Materials
by Haibing Xiao, Wei Zhang, Yongquan Zhou, Mingjun Liu and Guiyao Zhou
Crystals 2022, 12(6), 867; https://doi.org/10.3390/cryst12060867 - 19 Jun 2022
Cited by 3 | Viewed by 1943
Abstract
To effectively improve the cutting quality of sapphire and optimize ultrafast picosecond laser cutting technology, this paper presents a new numerical simulation method and an experimental study of the ultrafast double-laser cutting of sapphire materials. The optimal cutting technology and the numerical simulation [...] Read more.
To effectively improve the cutting quality of sapphire and optimize ultrafast picosecond laser cutting technology, this paper presents a new numerical simulation method and an experimental study of the ultrafast double-laser cutting of sapphire materials. The optimal cutting technology and the numerical simulation of the temperature field of the ultrafast picosecond laser cutting of sapphire were designed independently. The principle is based on double-laser-beam cutting using an ultrashort pulse and a CO2 beam; the ultrashort pulse is focused on the material through a laser filamentous cutting head and perforated, and it moves at a speed of up to 200 mm/s to form the desired cutting line. Then, a CO2 beam is used for heating, and the principle of heat bilges and cold shrink causes the rapid separation of products. Furthermore, an SEM tester was used to characterize and analyze the microstructure and properties of sapphire materials. A microscope was used to analyze the composition of the cutting micro-area and explore the general mechanism of laser cutting sapphire. The results showed that the proposed method greatly improves efficiency and precision; in addition, the chipping size of sapphire is less than 4 μm. Full article
(This article belongs to the Special Issue Advanced Laser Technology and Applications)
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15 pages, 2556 KiB  
Article
Study on Fluorescence Properties of Green-Blue Apatite
by Qicheng Yan, Ziyuan Liu and Ying Guo
Crystals 2022, 12(6), 866; https://doi.org/10.3390/cryst12060866 - 19 Jun 2022
Cited by 1 | Viewed by 2743
Abstract
The fluorescence phenomenon of apatite is an important feature. In this paper, three apatites with uniform transition from green to blue were selected, and the fluorescence color characteristics of the samples were observed under UV fluorescent lamp and DiamondView. With 3D fluorescence technology, [...] Read more.
The fluorescence phenomenon of apatite is an important feature. In this paper, three apatites with uniform transition from green to blue were selected, and the fluorescence color characteristics of the samples were observed under UV fluorescent lamp and DiamondView. With 3D fluorescence technology, combined with LA-ICP-MS, this paper aims to comprehensively test the fluorescence phenomenon of apatite to explore the relationship between apatite fluorescence and elements and analyze the fluorescence color characteristics. With the experiments mentioned above, this paper explores the fluorescent color characteristics of gemstones and their influencing factors to improve the color system of apatite. UV and DiamondView experiments show that with the change from green to blue, apatites show weak purple–red to strong pink–purple fluorescence. The 3D fluorescence test shows that the samples have two notable fluorescence emission peaks: (1) The fluorescence peak group composed of the double fluorescence peaks around 600 nm is generated by the excitation light source at 450 and 470 nm and a weaker fluorescence peak generated by the excitation at 400 nm; (2) The fluorescence emission peak of the sample gradually becomes prominent and the intensity increases significantly near the areas where the excitation wavelength is 280–330 nm and where the emission wavelength is 380 nm. According to the LA-ICP-MS test combined with the element properties, the fluorescence peak group (1) is mainly affected by Mn2+, Sm3+, and Pr3+, which emit orange fluorescence. The fluorescence emission peak (2) is caused by Ce3+, Eu3+, Dy3+, and Tb3+, which emit purple fluorescence. The mixing of the two fluorescent colors results in violet–pink fluorescence. Full article
(This article belongs to the Topic Optoelectronic Materials)
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14 pages, 5485 KiB  
Article
Charge State Effects in Swift-Heavy-Ion-Irradiated Nanomaterials
by Kristina Tomić Luketić, Juraj Hanžek, Catalina G. Mihalcea, Pavo Dubček, Andreja Gajović, Zdravko Siketić, Milko Jakšić, Corneliu Ghica and Marko Karlušić
Crystals 2022, 12(6), 865; https://doi.org/10.3390/cryst12060865 - 19 Jun 2022
Cited by 6 | Viewed by 1914
Abstract
The aim of this experimental work was to investigate the influence of the ion beam charge state on damage production in nanomaterials. To achieve this, we employed Raman spectroscopy, atomic force microscopy, and transmission electron microscopy to investigate nanomaterials irradiated by a 23 [...] Read more.
The aim of this experimental work was to investigate the influence of the ion beam charge state on damage production in nanomaterials. To achieve this, we employed Raman spectroscopy, atomic force microscopy, and transmission electron microscopy to investigate nanomaterials irradiated by a 23 MeV I beam. We found a significant influence of the ion charge state on damage production in monolayer graphene, but found no evidence of this effect in bilayer and trilayer graphene, nor in graphite. Furthermore, we found no evidence of this effect in CaF2 and SiO2 nanocrystals irradiated with the same ion beam. Full article
(This article belongs to the Special Issue 2D Crystalline Nanomaterials)
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10 pages, 4172 KiB  
Article
Properties of Self-Compacting Concrete Using Multi-Component Blend Binders for CO2 Reduction
by Yong Jic Kim
Crystals 2022, 12(6), 864; https://doi.org/10.3390/cryst12060864 - 19 Jun 2022
Viewed by 1195
Abstract
This paper aims to reduce the quantity of cement used by up to 80% by utilizing industrial by-products. By reducing the amount of cement used, there is an effect of reducing CO2 emissions during cement manufacturing. To reduce the amount of cement [...] Read more.
This paper aims to reduce the quantity of cement used by up to 80% by utilizing industrial by-products. By reducing the amount of cement used, there is an effect of reducing CO2 emissions during cement manufacturing. To reduce the amount of cement used, ground granulated blast-furnace slag (GGBF), fly-ash (FA), and calcium carbonate (CC) were used as substitute materials for cement. CC is a by-product, discharged by collecting CO2 emitted from a coal-fired power plant and reacting with additives. The specific surface area and the average particle size of CC used are 12,239 cm2/g and 5.9 μm (D50), respectively. The viscosity of pastes that contained GGFF and FA decreased by up to 51 and 49% respectively compared to the use of only cement (OPC) paste. However, paste using with CC increased up to 23% in relation to plain. As a result of measuring slump flow, segregation resistance ability, and filling ability to evaluate construction performance, slump flow was reduced by up to 3% (G40F10C30) in relation to plain concrete. Segregation resistance ability of fresh concrete using, GGBF (15, 30, and 45%), FA (10, 20, and 30%), CC (10, 20, and 30%), the time it takes for the slump flow to reach 500 mm, time it takes to through the V-funnel showed a decreasing tendency as the usage of FA increased. However, CC increased with increasing mixing ratio. This trend is, the viscosity increase when CC was mixed in terms of rheology. Filling ability of fresh concrete using GGBF (15, 30, and 45%), FA (10, 20, and 30%) and CC (10, 20, and 30%), the criteria were met, and the average increase was 16% and the maximum was 20% in relation to plain concrete. In the case of compressive strength, the compressive strength at 1 day was found to be an average of 5 MPa when 80% of the cementitious was substituted. At 3 days, at least 8 MPa was measured. The compressive strength at 28 days showed a tendency to decrease as the mixing rate of CC increased, but was measured to be at least 34 MPa. The relationship between compressive strength and splitting tensile strength or elastic modulus at 28 days satisfies the standard range. Full article
(This article belongs to the Special Issue Crystalizations in Cementitous Composites)
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12 pages, 8561 KiB  
Article
Stable CsPbBr3 Nanocrystals—Decorated Nanoporous Gold for Optoelectronic Applications
by Jessica Satta, Andrea Pinna, Giorgio Pia, Luca Pilia, Carlo Maria Carbonaro, Daniele Chiriu, Luigi Stagi, Qader Abdulqader Abdullah and Pier Carlo Ricci
Crystals 2022, 12(6), 863; https://doi.org/10.3390/cryst12060863 - 18 Jun 2022
Cited by 1 | Viewed by 1916
Abstract
Halide perovskite colloidal nanocrystals have recently gained much attention thanks to their superior stability compared with their bulk counterpart and to their unique optical properties. In this paper, two systems combining nanocrystals and nanoporous gold are studied to create an optimal metal semiconductor [...] Read more.
Halide perovskite colloidal nanocrystals have recently gained much attention thanks to their superior stability compared with their bulk counterpart and to their unique optical properties. In this paper, two systems combining nanocrystals and nanoporous gold are studied to create an optimal metal semiconductor heterojunction that can be used in photocatalysis and photovoltaic devices. The perovskite degradation phenomenon is observed when the nanoporous gold powder is mixed into the hexane suspension of nanocrystals, while the charge separation efficiency is increased by synthesizing the nanocrystals directly onto the gold porous structure. The analysis of the structural and optical properties evidences an energy transfer efficiency of 47%, along with the high structural stability of the hybrid system. Full article
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18 pages, 5181 KiB  
Article
Fabrication of Copper(II)-Coated Magnetic Core-Shell Nanoparticles Fe3O4@SiO2: An Effective and Recoverable Catalyst for Reduction/Degradation of Environmental Pollutants
by Jaber Dadashi, Mohammad Khaleghian, Babak Mirtamizdoust, Younes Hanifehpour and Sang Woo Joo
Crystals 2022, 12(6), 862; https://doi.org/10.3390/cryst12060862 - 18 Jun 2022
Cited by 7 | Viewed by 2336
Abstract
In this work, we report the synthesis of a magnetically recoverable catalyst through immobilizing copper (II) over the Fe3O4@SiO2 nanoparticles (NPs) surface [Fe3O4@SiO2-L–Cu(II)] (L = pyridine-4-carbaldehyde thiosemicarbazide). Accordingly, synthesized catalysts were determined [...] Read more.
In this work, we report the synthesis of a magnetically recoverable catalyst through immobilizing copper (II) over the Fe3O4@SiO2 nanoparticles (NPs) surface [Fe3O4@SiO2-L–Cu(II)] (L = pyridine-4-carbaldehyde thiosemicarbazide). Accordingly, synthesized catalysts were determined and characterized by energy dispersive X-ray spectrometry (EDS), X-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FT-IR), vibrating sample magnetometer (VSM), field emission scanning electron microscopy (FESEM), and thermogravimetric-differential thermal analysis (TG-DTA) procedures. The [Fe3O4@SiO2-L–Cu(II)] was used for the reduction of Cr(VI), 4-nitrophenol (4-NP) and organic dyes such as Congo Red (CR) and methylene blue (MB) in aqueous media. Catalytic performance studies showed that the [Fe3O4@SiO2–L–Cu(II)] has excellent activity toward reduction reactions under mild conditions. Remarkable attributes of this method are high efficiency, removal of a homogeneous catalyst, easy recovery from the reaction mixture, and uncomplicated route. The amount of activity in this catalytic system was almost constant after several stages of recovery and reuse. The results show that the catalyst was easily separated and retained 83% of its efficiency after five cycles without considerable loss of activity and stability. Full article
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11 pages, 7157 KiB  
Article
X-ray Structure Analyses and Biological Evaluations of a New Cd(II) Complex with S-Triazine Based Ligand
by Kholood A. Dahlous, Atallh A. M. Alotaibi, Necmi Dege, Ayman El-Faham, Saied M. Soliman and Heba M. Refaat
Crystals 2022, 12(6), 861; https://doi.org/10.3390/cryst12060861 - 18 Jun 2022
Cited by 6 | Viewed by 1588
Abstract
The crystal structure of a new penta-coordinated Cd(II) complex of the formula [Cd(BPMT)Br2] was presented. This Cd(II) complex was synthesized by mixing Cd(NO3)2·4H2O and 2,4-bis(3,5-dimethyl-1H-pyrazol-1-yl)-6-methoxy-1,3,5-triazine (BPMT) in the presence [...] Read more.
The crystal structure of a new penta-coordinated Cd(II) complex of the formula [Cd(BPMT)Br2] was presented. This Cd(II) complex was synthesized by mixing Cd(NO3)2·4H2O and 2,4-bis(3,5-dimethyl-1H-pyrazol-1-yl)-6-methoxy-1,3,5-triazine (BPMT) in the presence of KBr. It crystallized in the monoclinic crystal system and P21/n space group. The crystal parameters are a = 11.3680(8) Å, b = 11.1648(8) Å, c = 15.8593(11) Å, and β = 103.563(2)°, while the unit cell volume is 2190.6(12) Å3 and it comprised four molecules. The supramolecular structure of the [Cd(BPMT)Br2] complex is mainly controlled by the intermolecular Br∙∙∙H interactions. Hirshfeld calculations predicted the H∙∙∙H (38.1%), Br∙∙∙H (24.3%), C∙∙∙H (11.1%), and N∙∙∙H (9.5%) interactions are the most dominant. Biological evaluations for the antimicrobial and anticancer properties of the studied complex are presented. The Cd(II) complex has better anticancer and antibacterial activities than the free BPMT ligand. The anticancer activity against lung carcinoma (A-549) is higher for the former (18.64 ± 1.09 µg/mL) compared to the latter (372.79 ± 13.64 µg/mL). Additionally, the best antibacterial activity for the Cd(II) complex was found against B. subtilis. Full article
(This article belongs to the Special Issue New Trends in Crystals at Saudi Arabia (Volume II))
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14 pages, 4945 KiB  
Article
Structural, Thermal and Functional Properties of a Hybrid Dicyanamide-Perovskite Solid Solution
by Javier García-Ben, Jorge Salgado-Beceiro, Ignacio Delgado-Ferreiro, Pedro Dafonte-Rodríguez, Jorge López-Beceiro, Ramón Artiaga, Socorro Castro-García, Manuel Sánchez-Andújar, Juan Manuel Bermúdez-García and María Antonia Señarís-Rodríguez
Crystals 2022, 12(6), 860; https://doi.org/10.3390/cryst12060860 - 18 Jun 2022
Viewed by 1469
Abstract
In Solid-State Chemistry, a well-known route to obtain new compounds and modulate their properties is the formation of solid solutions, a strategy widely exploited in the case of classical inorganic perovskites but relatively unexplored among emergent hybrid organic–inorganic perovskites (HOIPs). In this work, [...] Read more.
In Solid-State Chemistry, a well-known route to obtain new compounds and modulate their properties is the formation of solid solutions, a strategy widely exploited in the case of classical inorganic perovskites but relatively unexplored among emergent hybrid organic–inorganic perovskites (HOIPs). In this work, to the best of our knowledge, we present the first dicyanamide-perovskite solid solution of [TPrA][Co0.5Ni0.5(dca)3] and study its thermal, dielectric and optical properties, comparing them with those of the parent undoped compounds [TPrA][Co(dca)3] and [TPrA][Ni(dca)3]. In addition, we show that the prepared doped compound can be used as a precursor that, by calcination, allows CNTs with embedded magnetic Ni:Co alloy nanoparticles to be obtained through a fast and much simpler synthetic route than other complex CVD or arc-discharge methods used to obtain this type of material. Full article
(This article belongs to the Special Issue Solid State Chemistry: Memorial Issue for Professor Emilio Morán)
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13 pages, 4515 KiB  
Article
Factors Influencing Recognition Capability of Inverse Opal Structured Photonic Crystal Sensors
by Chaokun Yang, Mengyao Pan and Xin Zhao
Crystals 2022, 12(6), 859; https://doi.org/10.3390/cryst12060859 - 17 Jun 2022
Viewed by 1161
Abstract
Nowadays, many kinds of colloidal photonic crystal (PC) sensors with inverse opal (IO) structures have been developed. However, there are few systematic studies on the factors influencing their recognition capability and responsiveness capability. In this paper, the relationships between recognition capability of IO [...] Read more.
Nowadays, many kinds of colloidal photonic crystal (PC) sensors with inverse opal (IO) structures have been developed. However, there are few systematic studies on the factors influencing their recognition capability and responsiveness capability. In this paper, the relationships between recognition capability of IO structured PC sensors and all the parameters in Bragg–Snell’s law have been explored. In addition, research on the recognition ability of PC sensors typically focuses only on the refractive index difference between the identified substances. Herein, we define two concepts, namely the absolute refractive index difference and the relative refractive index difference, and prove that the recognition ability not only relies on the absolute refractive index between the identified substances, but also on the relative refractive index. Bragg–Snell’s law analysis confirms that the responsiveness capability is directly proportional to the void size of the IO structure, which is also confirmed by the finite difference time domain (FDTD) method. It is believed that these systematic studies have important guiding significance for creating advanced IO structured PC sensors. Full article
(This article belongs to the Section Inorganic Crystalline Materials)
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23 pages, 22661 KiB  
Review
Review of Additive Manufacturing Techniques for Large-Scale Metal Functionally Graded Materials
by Ruiying Zhang, Fan Jiang, Long Xue and Junyu Yu
Crystals 2022, 12(6), 858; https://doi.org/10.3390/cryst12060858 - 17 Jun 2022
Cited by 6 | Viewed by 3232
Abstract
Functionally graded materials (FGMs), which constitute a new type of composite material, have received considerable attention in industry because of the spatial gradient of their composition and the microstructure-induced gradient in their material performance, which make them better suited for high-performance multifunctional applications. [...] Read more.
Functionally graded materials (FGMs), which constitute a new type of composite material, have received considerable attention in industry because of the spatial gradient of their composition and the microstructure-induced gradient in their material performance, which make them better suited for high-performance multifunctional applications. Additive manufacturing (AM) has become one of the most promising techniques for the manufacture of materials and structures because of its high flexibility. The combination of advanced materials (FGMs) and advanced manufacturing methods (AM) is expected to facilitate the further development of such engineering materials. In this paper, the definition, historical development and material gradient types of FGMs are introduced. The classification, process principle and typical research results of the AM of metal FGMs are summarized and discussed. In particular, the research status of wire and arc additive manufacture (WAAM), which is more suitable for the preparation of large-scale metal FGMs, is reviewed in detail according to the types of FGMs, and a double-wire bypass plasma arc additive manufacturing technique, which is suitable for inducing a gradient along the direction of single-pass cladding, is proposed. On the basis of this summary of the important achievements made to date, future research is proposed. Full article
(This article belongs to the Special Issue Physical Mechanism of Welding of Metallic Materials)
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12 pages, 9527 KiB  
Article
The Effect of Doping High Volume Magnesium Sulfate on Properties of Magnesium Oxychloride Cement
by Qing Huang, Weixin Zheng, Ying Li, Chenggong Chang, Jing Wen, Jinmei Dong and Xueying Xiao
Crystals 2022, 12(6), 857; https://doi.org/10.3390/cryst12060857 - 17 Jun 2022
Cited by 3 | Viewed by 1411
Abstract
The composite gelling system of chlorine and magnesium thioxide was prepared by mixing different mass fractions of magnesium sulfate solution into MOC. Detailed studies regarding the influences of magnesium sulfate replacing magnesium chloride on the setting time, compressive strength, and water resistance of [...] Read more.
The composite gelling system of chlorine and magnesium thioxide was prepared by mixing different mass fractions of magnesium sulfate solution into MOC. Detailed studies regarding the influences of magnesium sulfate replacing magnesium chloride on the setting time, compressive strength, and water resistance of magnesium oxychloride cement (MOC) have been carried out in this paper. The phase composition and micro morphology of the hydration products in the mixed system were analyzed by XRD and SEM. The results show that the addition of magnesium sulfate prolongs the setting time and reduces the compressive strength of the mixed MOC. Compared with the primordial MOC system, the water resistance of the mixed system improved, with the mixed system exhibiting optimal water resistance when the mass fraction of magnesium sulfate was 30%. The phases of the mixed system were composed of 5Mg(OH)2·MgCl2·8H2O and 5Mg(OH)2·MgSO4·7H2O phases. The microscopic morphology shows that the interior of air-cured MOC was composed of a large number of needle-like crystals, and continuous crystal structures have close contact and a strong bonding force. Cracks and pores appear on the surface after submerging in water, and the crystallization state of the internal crystals becomes worse. The compressive strength and water stability of MOC were closely related to the crystal morphology. Full article
(This article belongs to the Special Issue Advances in Cement-Based and Construction Materials)
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12 pages, 3489 KiB  
Article
Thermodynamic Characterization of a Highly Transparent Microfluidic Chip with Multiple On-Chip Temperature Control Units
by Tianhang Yang, Jinxian Wang, Sining Lv, Songjing Li and Gangyin Luo
Crystals 2022, 12(6), 856; https://doi.org/10.3390/cryst12060856 - 17 Jun 2022
Cited by 17 | Viewed by 1588
Abstract
Indium tin oxide (ITO) is a functional material with great transparency, machinability, electrical conductivity and thermo–sensitivity. Based on its excellent thermoelectric performance, we designed and fabricated a multilayer transparent microfluidic chip with multiple sets of on–chip heating, local temperature measurement and positive on–chip [...] Read more.
Indium tin oxide (ITO) is a functional material with great transparency, machinability, electrical conductivity and thermo–sensitivity. Based on its excellent thermoelectric performance, we designed and fabricated a multilayer transparent microfluidic chip with multiple sets of on–chip heating, local temperature measurement and positive on–chip cooling function units. Temperature control plays a significant role in microfluidic approaches, especially in the devices that are designed for bioengineering, chemical synthesis and disease detection. The transparency of the chip contributes to achieve the real–time observation of fluid flow and optical detection. The chip consists of a temperature control layer made with an etched ITO deposited glass, a PDMS (polydimethylsiloxane) fluid layer, a PDMS cooling and flow control layer. The performances of the ITO on–chip microheaters, ITO on–chip temperature sensors and two coolants were tested and analyzed in different working conditions. The positive on–chip heating and cooling were proved to be area-specific under a large temperature–regulating range. This PDMS–ITO–glass based chip could be applied to both temporal and spatial stable temperature–regulating principles for various purposes. Full article
(This article belongs to the Special Issue Functional Materials and Metamaterials)
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11 pages, 18128 KiB  
Article
Achievement of Unidirectional Aluminum Tin Oxide/UV-Curable Polymer Hybrid Film via UV Nanoimprinting Lithography for Uniform Liquid Crystal Alignment
by Dong-Wook Lee, Dong-Hyun Kim, Jonghoon Won, Jin-Young Oh and Dae-Shik Seo
Crystals 2022, 12(6), 855; https://doi.org/10.3390/cryst12060855 - 17 Jun 2022
Viewed by 1531
Abstract
A uniform unidirectional nanostructure composed of aluminum tin oxide and ultraviolet (UV)-curable polymer is introduced herein. The nanostructure was produced by UV-nanoimprint lithography (UV-NIL), and the fabricated hybrid film was used as a uniform liquid crystal (LC) alignment layer. Atomic force microscopy and [...] Read more.
A uniform unidirectional nanostructure composed of aluminum tin oxide and ultraviolet (UV)-curable polymer is introduced herein. The nanostructure was produced by UV-nanoimprint lithography (UV-NIL), and the fabricated hybrid film was used as a uniform liquid crystal (LC) alignment layer. Atomic force microscopy and line profile analysis were performed to confirm a well-ordered nanostructure with 760 nm periodicity and 30 nm height. X-ray photoelectron spectroscopy analysis was also conducted to examine the chemical modifications to the hybrid film surface during UV exposure. Optical transmittance investigation of the nanopatterned hybrid film revealed its compatibility for LC device application. Stable, uniform, and homogeneous LC alignment on the hybrid film was confirmed by polarized optical microscopy observance and analysis of LC pretilt angle. The unidirectional structure on the film surface enabled uniform LC orientation along with surface anisotropy property. Hence, we expect that the proposed UV-NIL process can be applied to fabricate high-resolution unidirectional nanostructures with various inorganic/organic hybrid materials and that these nanostructures have high potential for next-generation LC systems. Full article
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17 pages, 3275 KiB  
Article
Luminescence and Structural Characterization of Gd2O2S Scintillators Doped with Tb3+, Ce3+, Pr3+ and F for Imaging Applications
by Alessia De Martinis, Luigi Montalto, Lorenzo Scalise, Daniele Rinaldi, Paolo Mengucci, Christos Michail, George Fountos, Nicki Martini, Vaia Koukou, Ioannis Valais, Athanasios Bakas, Christine Fountzoula, Ioannis Kandarakis and Stratos David
Crystals 2022, 12(6), 854; https://doi.org/10.3390/cryst12060854 - 17 Jun 2022
Cited by 3 | Viewed by 2229
Abstract
Radiodiagnostic technologies are powerful tools for preventing diseases and monitoring the condition of patients. Medicine and sectors such as industry and research all use this inspection methodology. This field demands innovative and more sophisticated systems and materials for improving resolution and sensitivity, leading [...] Read more.
Radiodiagnostic technologies are powerful tools for preventing diseases and monitoring the condition of patients. Medicine and sectors such as industry and research all use this inspection methodology. This field demands innovative and more sophisticated systems and materials for improving resolution and sensitivity, leading to a faster, reliable, and safe diagnosis. In this study, a large characterization of gadolinium oxysulfide (Gd2O2S) scintillator screens for imaging applications has been carried out. Seven scintillator samples were doped with praseodymium (Pr3+), terbium (Tb3+) activators and co-doped with praseodymium, cerium, and fluorine (Gd2O2S:Pr,Ce,F). The sample screens were prepared in the laboratory in the form of high packing density screens, following the methodology used in screen sample preparation in infrared spectroscopy and luminescence. Parameters such as quantum detection efficiency (QDE), energy absorption efficiency (EAE), and absolute luminescence efficiency (ALE) were evaluated. In parallel, a structural characterization was performed, via XRD and SEM analysis, for quality control purposes as well as for correlation with optical properties. Spatial resolution properties were experimentally evaluated via the Modulation Transfer Function. Results were compared with published data about Gd2O2S:Pr,Ce,F screens produced with a standard method of a sedimentation technique. In particular, the ALE rose with the X-ray tube voltage up to 100 kVp, while among the different dopants, Gd2O2S:Pr exhibited the highest ALE value. When comparing screens with different thicknesses, a linear trend for the ALE value was not observed; the highest ALE value was measured for the 0.57 mm thick Gd2O2S:Pr,Ce,F sample, while the best MTF values were found in the thinner Gd2O2S:Pr,Ce,F screen with 0.38 mm thickness. Full article
(This article belongs to the Section Inorganic Crystalline Materials)
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8 pages, 1735 KiB  
Article
Stoichiometric Growth of Monolayer FeSe Superconducting Films Using a Selenium Cracking Source
by Kejing Zhu, Heng Wang, Yuying Zhu, Yunyi Zang, Yang Feng, Bingbing Tong, Dapeng Zhao, Xiangnan Xie, Kai Chang, Ke He and Chong Liu
Crystals 2022, 12(6), 853; https://doi.org/10.3390/cryst12060853 - 17 Jun 2022
Cited by 1 | Viewed by 1699
Abstract
As a novel interfacial high-temperature superconductor, monolayer FeSe on SrTiO3 has been intensely studied in the past decade. The high selenium flux involved in the traditional growth method complicates the film’s composition and entails more sample processing to realize the superconductivity. Here [...] Read more.
As a novel interfacial high-temperature superconductor, monolayer FeSe on SrTiO3 has been intensely studied in the past decade. The high selenium flux involved in the traditional growth method complicates the film’s composition and entails more sample processing to realize the superconductivity. Here we use a Se cracking source for the molecular beam epitaxy growth of FeSe films to boost the reactivity of the Se flux. Reflection high-energy electron diffraction shows that the growth rate of FeSe increases with the increasing Se flux when the Fe flux is fixed, indicating that the Se over-flux induces Fe vacancies. Through careful tuning, we find that the proper Se/Fe flux ratio with Se cracked that is required for growing stoichiometric FeSe is close to 1, much lower than that with the uncracked Se flux. Furthermore, the FeSe film produced by the optimized conditions shows high-temperature superconductivity in the transport measurements without any post-growth treatment. Our work reinforces the importance of stoichiometry for superconductivity and establishes a simpler and more efficient approach to fabricating monolayer FeSe superconducting films. Full article
(This article belongs to the Special Issue Superconductors: Materials, Microstructures and Applications)
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10 pages, 2971 KiB  
Article
Crystallization Kinetics of the Fe68Nb6B23Mo3 Glassy Ribbons Studied by Differential Scanning Calorimetry
by Yongqin Liu, Man Zhu, Yuanyuan Du, Lijuan Yao and Zengyun Jian
Crystals 2022, 12(6), 852; https://doi.org/10.3390/cryst12060852 - 17 Jun 2022
Cited by 3 | Viewed by 1480
Abstract
Fe-based metallic glass has wide industrial application due to its unique mechanical behavior and magnetic properties. In the present work, the non-isothermal crystallization kinetics in Fe68Nb6B23Mo3 glassy alloys were investigated by differential scanning calorimeter (DSC). The [...] Read more.
Fe-based metallic glass has wide industrial application due to its unique mechanical behavior and magnetic properties. In the present work, the non-isothermal crystallization kinetics in Fe68Nb6B23Mo3 glassy alloys were investigated by differential scanning calorimeter (DSC). The results indicate that both the glass transformation and crystallization process display an obvious kinetic effect. The activation energy is calculated using Kissinger’s method and Ozawar’s method. The activation energy for Tg (glass transition temperatures), Tx (crystallization initiation temperatures) and Tp (crystallization peak temperatures) calculated from Kissinger equation, is 308 ± 4, 342 ± 5 and 310 ± 7 kJ mol−1, respectively. The activation energy for Tg, Tx and Tp calculated from Ozawa equation is 322 ± 3, 356 ± 5 and 325 ± 7 kJ mol−1, respectively. With the increase of the crystallization volume fraction x, the Avrami exponent n(x) first decreases and then increases. At the preliminary step, 0 < x < 0.25, 2.5 < n(x) < 4.0 stands for the growth from a small size with an increasing nucleation rate. When 0.25 < x < 0.71, n(x) decreases from 2.5 to 1.5, indicating that this stage is controlled by the growth of small particles with a decreasing nucleation rate. Full article
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14 pages, 4762 KiB  
Article
Effects of Basicity and Al2O3 Content on Viscosity and Crystallization Behavior of Super-High-Alumina Slag
by Shuai Wang, Ying Jiang, Yufeng Guo, Zhuang Yang, Feng Chen, Lingzhi Yang and Guang Li
Crystals 2022, 12(6), 851; https://doi.org/10.3390/cryst12060851 - 16 Jun 2022
Cited by 4 | Viewed by 1672
Abstract
The CaO-SiO2-MgO-Al2O3 slags with high alumina content are widely applied in various pyrometallurgical processes. However, for super-high-alumina slags, especially for those with alumina content of more than 25 wt%, there is a lack of relevant studies about the [...] Read more.
The CaO-SiO2-MgO-Al2O3 slags with high alumina content are widely applied in various pyrometallurgical processes. However, for super-high-alumina slags, especially for those with alumina content of more than 25 wt%, there is a lack of relevant studies about the properties of slag. The melting behavior, viscosity, structural property, and crystallization behavior of high-alumina slag with the fixed MgO content of 11.13 wt% and Al2O3 content from 27.61 wt% to 40 wt% were investigated. The results revealed that the liquidus temperatures and complete solidification temperatures of slag increased with the increasing binary basicity and Al2O3 content. The melting temperature and viscosity of the CaO-SiO2-11.13wt%MgO-Al2O3 slag system increased with the increasing basicity from 0.8 to 1 and Al2O3 content from 27.61 wt% to 40 wt%. The increase in Al2O3 caused the formation of high-crystallinity and high melting point materials in the slag, such as spinel and Åkermanite. A large number of non-uniform phases could quickly crystallize out of the solids present in the slag melt, thereby increasing the slag viscosity and deteriorating the fluidity of the slag. Full article
(This article belongs to the Topic Iron Concentrate Particles)
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24 pages, 11106 KiB  
Article
Mechanical Response and Fracture of Pultruded Carbon Fiber/Epoxy in Various Modes of Loading
by Arie Bussiba, Ilan Gilad, Snir Lugassi, Sigal David, Jacob Bortman and Zohar Yosibash
Crystals 2022, 12(6), 850; https://doi.org/10.3390/cryst12060850 - 16 Jun 2022
Cited by 3 | Viewed by 1687
Abstract
Pultrusion is a continuous process of forming constant cross-sections of unidirectional composites with a significant long length. This unique process is implemented widely in the composites industry due to its continuous, automated, and highly productive nature. The current research focused on mechanical response [...] Read more.
Pultrusion is a continuous process of forming constant cross-sections of unidirectional composites with a significant long length. This unique process is implemented widely in the composites industry due to its continuous, automated, and highly productive nature. The current research focused on mechanical response characterization at three modes of loading: tensile, compression, and shear loading of coupons made from a graphite/epoxy 1 mm sheet. In addition, the effects of holes and notches were examined in terms of mechanical properties. The mechanical behavior was assessed through stress–strain curves with careful attention on the curve profile, macroscopic fracture modes observations, and optical microscopic tracking with continuous video records. The mechanical tests follow standards with some critiques on the shear test. Finite element analysis (FEA) was used to accurately determine the shear modulus, and for other mechanical investigations. By nature, under tension, the unidirectional fiber composite at 0° orientation exhibits high strength (2800 MPa), with very low strength at 90° orientation (40 MPa). Both orientations display linear mechanical behavior. Under compression, 0° orientation exhibits low strength (1175 MPa), as compared to tension due to the kinking phenomena, which is the origin in the deviation from linear behavior. Under shear, both orientations exhibit approximately the same shear strength (45 MPa for 0° and 47 MPa for 90°), which is mainly related to the mechanical properties of the epoxy resin. In general, in the presence of holes, the remote fracture stress in the various modes of loading did not change significantly, as compared to uniform coupons; however, some localized delamination crack growth occurred at the vicinity of the holes, manifested by load drops up to the final fracture. This behavior is also attributed to the tension of notched coupons. FEA shows that the shear values were unaffected by manufacturing imperfections, coupon thickness, and by asymmetrical gripping up to 3 mm, with minor effect in the case of a small deviation from the load line. Selected experimental tests support the FEA tendencies. Full article
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10 pages, 3716 KiB  
Article
TiN–Fe Vertically Aligned Nanocomposites Integrated on Silicon as a Multifunctional Platform toward Device Applications
by Matias Kalaswad, Di Zhang, Bethany X. Rutherford, Juanjuan Lu, James P. Barnard, Zihao He, Juncheng Liu, Haohan Wang, Xiaoshan Xu and Haiyan Wang
Crystals 2022, 12(6), 849; https://doi.org/10.3390/cryst12060849 - 16 Jun 2022
Cited by 3 | Viewed by 1807
Abstract
Transition metal nitrides such as titanium nitride (TiN) possess exceptional mechanical-, chemical-, and thermal-stability and have been utilized in a wide variety of applications ranging from super-hard, corrosion-resistive, and decorative coatings to nanoscale diffusion barriers in semiconductor devices. Despite the ongoing interest in [...] Read more.
Transition metal nitrides such as titanium nitride (TiN) possess exceptional mechanical-, chemical-, and thermal-stability and have been utilized in a wide variety of applications ranging from super-hard, corrosion-resistive, and decorative coatings to nanoscale diffusion barriers in semiconductor devices. Despite the ongoing interest in these robust materials, there have been limited reports focused on engineering high-aspect ratio TiN-based nanocomposites with anisotropic magnetic and optical properties. To this end, we explored TiN–Fe thin films with self-assembled vertical structures integrated on Si substrates. We showed that the key physical properties of the individual components (e.g., ferromagnetism from Fe) are preserved, that vertical nanostructures promote anisotropic behavior, and interactions between TiN and Fe enable a special magneto-optical response. This TiN–Fe nanocomposite system presents a new group of complex multifunctional hybrid materials that can be integrated on Si for future Si-based memory, optical, and biocompatible devices. Full article
(This article belongs to the Special Issue Strain-Engineered Nanocomposites towards Multifunctionalities)
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12 pages, 3318 KiB  
Article
Evolution of Structure and Properties of Micro-Nano Structure 2507 Duplex Stainless Steel Prepared by Aluminothermic Reduction
by Faqi Zhan, Xiao Liu, Hua Zhang, Keliang Wang, Shipeng Xu, Min Zhu, Yuehong Zheng and Peiqing La
Crystals 2022, 12(6), 848; https://doi.org/10.3390/cryst12060848 - 16 Jun 2022
Cited by 2 | Viewed by 1481
Abstract
In this work, a large ingot of micro-nano structure 2507 duplex stainless steel was prepared in a single step using the aluminothermic reaction method. Chromium having different excess fractions were added to reaction powders to make up for evaporation loss, and the results [...] Read more.
In this work, a large ingot of micro-nano structure 2507 duplex stainless steel was prepared in a single step using the aluminothermic reaction method. Chromium having different excess fractions were added to reaction powders to make up for evaporation loss, and the results show that the composition and structure of 2507 duplex stainless steel with a chromium excess ratio of 70% are satisfactory. The volume fraction of nanocrystalline in as-cast alloy was 41% and the average grain size was 34 nm. Additionally, the anticipated steels were rolled roughly with deformation of 40% at 1000 °C and followed by fine rolling with deformation of 30, 50 and 70%, separately, at 800 °C. Then, the effects of rolling deformation and precipitation on mechanical properties were studied in detail. Compared with the as-cast alloy, there was no phase transformation in the alloys with deformation of 30 and 50%, and they were still composed of γ and α phases, whereas the σ phase appeared in the alloy with deformation of 70%. When the deformation was 50%, the rolled alloy achieved the best performance, and the tensile strength, yield strength, and elongation were 912 MPa, 523 MPa, and 24.3%, respectively. Full article
(This article belongs to the Special Issue Structural Changes during Steel Processing)
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