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A unique functionality was reported for a thin-film soft magnetic strip with a certain angle of inclined magnetic anisotropy. It can switch magnetic domain by applying a surface normal field with a certain distribution on the element. The domain switches between a single domain and a multi-domain. Our previous study shows that this phenomenon appears even in the case of the adjacent configuration of multiple narrow strips. It was also reported that the magnetic permeability for the alternating current (AC) magnetic field changes drastically in the frequency range from 10 kHz to 10 MHz as a function of the strength of the distributed magnetic field. In this paper, the correspondence of AC permeability and the magnetic domain as a function of the intensity of the distributed field is investigated. It was confirmed that the extension of the area of the Landau–Lifshitz-like multi-domain on the clustered narrow strips was observed as a function of the intensity of the distributed magnetic field, and this domain extension was matched with the permeability variation. The result leads to the application of this phenomenon to a tunable inductor, electromagnetic shielding, or a sensor for detecting and memorizing the existence of a distributed magnetic field generated by a magnetic nanoparticle in the vicinity of the sensor. [ABSTRACT FROM AUTHOR]

In this paper, a new medium entropy alloy with nominal composition of Gd33Co33Al34 was designed and fabricated into microfibers by a melt-extraction method. The microstructure, thermophysical parameters, and magnetocaloric properties of the obtained fibers were systematically analyzed. The results showed that the as-cast fibers show an amorphous matrix with embedded in situ nano crystals. The fibers show a good magnetocaloric effect with the maximum magnetic entropy change of ~6 J/kg·K for a field change of 5 T. Notably, the fibers show excellent cooling efficiencies with an RCP and RC of ~611.72 and ~487.38 J/kg, respectively. Though the as-cast fibers possess an amorphous/nanocrystal bi-phase structure, they still exhibit a second-order transition near a Curie temperature of ~96 K. Our findings provide a promising pathway towards developing new magnetocaloric materials with good magnetocaloric performances. [ABSTRACT FROM AUTHOR]

This paper is dealing with the dissolution mechanism of crystalline sulindac into amorphous Polyvinylpyrrolidone (PVP) upon heating and annealing at high temperatures. Special attention is paid on the diffusion mechanism of drug molecules in the polymer which leads to a homogeneous amorphous solid dispersion of the two components. The results show that isothermal dissolution proceeds through the growth of polymer zones saturated by the drug, and not by a progressive increase in the uniform drug concentration in the whole polymer matrix. The investigations also show the exceptional ability of temperature Modulated Differential Scanning Calorimetry (MDSC) to identify the equilibrium and out of equilibrium stages of dissolution corresponding to the trajectory of the mixture into its state diagram. [ABSTRACT FROM AUTHOR]

With the widespread use of magneto-sensitive elements, magnetic shields are an important part of electronic equipment, ultra-sensitive atomic sensors, and in basic physics experiments. Particularly in Spin-exchange relaxation-free (SERF) co-magnetometers, the magnetic shield is an important component for maintaining the SERF state. However, the inherent noise of magnetic shield materials is an important factor limiting the measurement sensitivity and accuracy of SERF co-magnetometers. In this paper, both amorphous and nanocrystalline materials were designed and applied as the innermost magnetic shield of an SERF co-magnetometer. Magnetic noise characteristics of different amorphous and nanocrystalline materials used as the internal magnetic shielding layer of the magnetic shielding system were analyzed. In addition, the effects on magnetic noise due to adding aluminum to amorphous and nanocrystalline materials were studied. The experimental results show that compared with an amorphous material, a nanocrystalline material as the inner magnetic shield layer can effectively reduce the magnetic noise and improve the sensitivity and precision of the rotation measurement. Nanocrystalline material is very promising for inner shield composition in SERF co-magnetometers. Furthermore, its ultra-thin structure and low cost have significant application value in the miniaturization of SERF co-magnetometers. [ABSTRACT FROM AUTHOR]

Cr 3 AlB 4 is one of the attractive compounds for high-temperature constrictive ceramics due to its combination of properties typical for ceramics or metals. In this study, the formation mechanism of Cr 3 AlB 4 , presented in the literature, was confirmed by means of the following analyses: XRD, DSC and SEM. According to them the synthesis of Cr 3 AlB 4 occurs is multi-step process with CrB 2 being formed first, followed by Cr 3 B 4 , which is intercalated by aluminium to form Cr 3 AlB 4. Furthermore, most scientific papers do not consider the possibility of synthesising MAB phase from the powders containing amorphous phase. In presented work, possibility of synthesis of Cr 3 AlB 4 from the powders containing the amorphous phase and influence of this kind of raw powders on synthesis process is shown. [ABSTRACT FROM AUTHOR]

Aceclofenac (ACF), a non-steroidal anti-inflammatory drug, was obtained in its amorphous state by cooling from melt. The glass transition was investigated using dielectric and calorimetric techniques, namely, dielectric relaxation spectroscopy (DRS), thermally stimulated depolarization currents (TSDC), and conventional and temperature-modulated differential scanning calorimetry (DSC and TM-DSC). The dynamic behavior in both the glassy and supercooled liquid states revealed multiple relaxation processes. Well below the glass transition, DRS was able to resolve two secondary relaxations, γ and β, the latter of which was also detectable by TSDC. The kinetic parameters indicated that both processes are associated with localized motions within the molecule. The main (α) relaxation was clearly observed by DRS and TSDC, and results from both techniques confirmed a non-Arrhenian temperature dependence of the relaxation times. However, the glass transition temperature (Tg) extrapolated from DRS data significantly differed from that obtained via TSDC, which in turn showed reasonable agreement with the calorimetric Tg (Tg-DSC = 9.2 °C). The values of the fragility index calculated by the three experimental techniques converged in attributing the character of a moderately fragile glass former to ACF. Above the α relaxation, TSDC showed a well-defined peak. In DRS, after "removing" the high-conductivity contribution using ε' derivative analysis, a peak with shape parameters αHN = βHN = 1 was also detected. The origin of these peaks, found in the full supercooled liquid state, has been discussed in the context of structural and dynamic heterogeneity. This is supported by significant differences observed between the FTIR spectra of the amorphous and crystalline samples, which are likely related to aggregation differences resulting from variations in the hydrogen bonds between the two phases. Additionally, the pronounced decoupling between translational and relaxational motions, as deduced from the low value of the fractional exponent x = 0.72, derived from the fractional Debye–Stokes–Einstein (FDSE) relationship, further supports this interpretation. [ABSTRACT FROM AUTHOR]

The catalyst is the pivotal component in CO2 electroreduction systems for converting CO2 into valuable products. Carbon-based single-atom materials (CSAMs) have emerged as promising catalyst candidates due to their low cost and high atomic utilization efficiency. The rational design of the morphology and microstructure of such materials is desirable but poses a challenge. Here, we employed different Mg(OH)2 templates to guide the fabrication of two kinds of amorphous nitrogen-doped carbon nanosheet-supported Fe single atoms (FeSNC) with rough and flat surface structures. In comparison to flat FeSNC with saturated FeN4 sites, the rough FeSNC (R-FeSNC) exhibited unsaturated FeN4−x sites and contracted Fe-N bond length. The featured structure endowed R-FeSNC with superior capacity of catalyzing CO2 reduction reaction, achieving an exceptional CO selectivity with Faradaic efficiency of 93% at a potential of −0.66 V vs. RHE. This study offers valuable insights into the design of CSAMs and provides a perspective for gaining a deeper understanding of their activity origins. [ABSTRACT FROM AUTHOR]

Ceramic particle-reinforced Fe-based amorphous coatings have received extensive attention due to their excellent strength and wear resistance. In this paper, TiN x /TiO y -enhanced Fe-based amorphous coatings were prepared by reactive plasma spraying technology, and the effect of eggshell-like TiN x /TiO y on the comprehensive mechanical properties of Fe-based amorphous coatings was systematically studied. The results showed that the hardness of the composite coating was significantly higher than that of the amorphous single-phase coating. Moreover, indentation experiments showed that TiN x /TiO y effectively confined crack growth in the amorphous phase. Though the bonding strength of the composite coating was lower than that of the pure amorphous coating, but still maintained a high bonding force of 20.68 MPa. Through the wear experiment, it was found that the wear scar of the composite coatings appeared plastic deformation, the friction coefficient and wear mass loss were both greatly reduced, and the optimal wear performance appeared in the composite coating with 15% Ti addition. In addition, SEM, EDS analysis, and the first-principles simulation results demonstrated the good bonding between Ti-containing compounds and Fe-based alloys. [ABSTRACT FROM AUTHOR]

The use of natural fibres in fibre-reinforced composites comes with drawbacks. They are highly hydrophilic, leading to high moisture absorption and poor interfacial adhesion in matrix-reinforcement bonds. This affects the fibres' thermal stability as well as mechanical properties, hence limiting their wider application. This paper reviewed different ways in which natural fibres have been treated to improve hydrophobicity, reinforcement-matrix interfacial adhesion and thermal stability. It will investigate. among others, treatments like alkali, acetylation, bleaching, silane, benzoylation and plasma, which have been found to improve fibre hydrophobicity. The literature reviewed showed that these methods work to improve mechanical, chemical, and morphological properties of natural fibres by removing the amorphous surface, thus allowing for more efficient load transfer on the fibrematrix surface. Studies in the literature found alkali treatment to be the most common surface modification treatment due to its simplicity and effectiveness. However, plasma treatment has emerged due to its lower processing time and chemical consumption. A comparative analysis of other improved properties was also investigated. [ABSTRACT FROM AUTHOR]

Indomethacin (INDO) is a synthetic non-steroidal antipyretic, analgesic, and anti-inflammatory drug that commonly exists in both amorphous and crystalline states. Its amorphous state (A-INDO) is utilized by pharmaceutical companies as an active pharmaceutical ingredient (API) in the production of INDO drugs due to its higher apparent solubility and bioavailability. The crystal state also encompasses various crystal forms such as the α-crystal form (α-INDO) and γ-crystal form (γ-INDO), with the highly crystalline and insoluble γ-INDO being commercially available. A-INDO, existing in a thermodynamically high-energy state, is susceptible to several factors during the preparation, storage, and transportation of API leading to its conversion into γ-INDO, thus impacting the bioavailability and efficacy of INDO drugs. Therefore, quantitative analysis of the A-INDO/γ-INDO content in INDO API becomes essential for controlling the production quality of INDO. The primary objective of this study is to investigate the feasibility of NIR for the quantitative analysis of A-INDO in INDO API, and to further elucidate its quantitative analysis mechanism. The NIR spectral data were collected for A-INDO and γ-INDO binary mixture samples with different resolutions, and these spectra were then selected and reconstructed using the interval partial least square (iPLS) method. Different pretreatment methods were employed to enhance the reconstructed spectra by highlighting relevant eigen information while eliminating invalid information caused by environmental factors or physical characteristics of samples. The most suitable PLSR model for quantitative analysis of A-INDO within the range of 0.0000–100.0000% w/w% was established, screened, and validated. From various perspectives, including distribution of spectral effective information, impact of resolution on PLSR model performance, variance contribution/cumulative variance contribution of PLSR model principal components (PCs), PCI loadings, relationship between spectral scores, and A-INDO content, feasibility assessment was conducted for the quantitative analysis of A-INDO in INDO using NIR spectroscopy. Additionally, a detailed investigation on the quantitative analysis mechanism of the optimal PLSR model was undertaken including the correlation between the characteristic peaks of spectra and information regarding hydrogen groups or hydrogen bonds in A-INDO or γ-INDO molecules. This study aims to provide theoretical support for the quantitative analysis of A-INDO in INDO API as well as serve as a reliable reference method for API quantification and quality control in similar drugs. [ABSTRACT FROM AUTHOR]

Until now, crystalline NiCo2S4 and its composites have demonstrated improved performance in supercapacitor applications compared to their oxide analogues due to their relatively higher electrical conductivity and multifaceted redox reaction. However, amorphous phase materials have recently shown promise in electrochemical energy storage systems. This work reports on amorphous NiCo2S4 with the help of urea via the hydrothermal method. It was noted that urea not only aided the amorphous formation but also served as a nitrogen precursor. In comparison, amorphous NiCo2S4 demonstrated a higher nitrogen atom% of 5.9 compared to 4.49 for crystalline NiCo2S4. Furthermore, the amorphous NiCo2S4 electrode exhibited superior electrochemical performance, with a specific capacitance of ~3506 F g−1, which was higher than the cNCS electrode's specific capacitance of ~2185 F g−1 at 2 A g−1. Additionally, aNCS in a two-electrode asymmetric supercapacitor exhibited a specific capacitance and an energy density of ~196 F g−1 and 56 Wh kg−1, respectively. [ABSTRACT FROM AUTHOR]

A novel experimental setup dedicated to the study of liquid and amorphous materials, on the white beam station of the PSICHE' beamline at SOLEIL, is described. The Beer-Lambert absorption method has been developed using a broad-spectrum (white) incident beam for in situ density measurements at extreme conditions of pressure and temperature. This technique has been combined with other existing X-ray techniques (radiographic imaging, tomography and combined angle energy dispersive X-ray diffraction). Such a multi-technical approach offers new possibilities for the characterization of liquid and amorphous materials at high pressure and high temperature. The strength of this approach is illustrated by density measurements of liquid gallium at pressures up to 4 GPa, combining the three independent X-ray techniques (the Beer-Lambert absorption method, tomography and X-ray diffraction). [ABSTRACT FROM AUTHOR]

Metallic biomaterials have been widely used in the field of medical implants for replacement purposes and/or for regeneration of tissue. Metals such as stainless steel (316 L), cobalt-chromium alloys and titanium alloys (Ti-6Al-4 V) are widely used as metallic implants today. However, they often exhibit unsatisfactory results such as stress shielding, the release of toxic ions and are often permanent and invasive – where a second surgery is required to remove the implant once the bone is fully healed. Magnesium as a biomaterial have attracted much attention recently due to its excellent biocompatibility, similar mechanical properties to bone and biodegradability. Unlike other metals and bio ceramics, the ability for magnesium alloys to undergo biodegradation eliminates the requirement for a second surgery to remove the implant. Additionally, the degradation of magnesium releases Mg2+ ions, which stimulates metabolism as they are a cofactor in numerous numbers of enzymes. Despite the advantages of magnesium alloys, the rapid degradation of magnesium proved to be challenging as the implant is unable to retain its structural integrity sufficiently enough to act as an implant. To improve the corrosion resistance of magnesium alloys, researchers have been working on the synthesis and characterization of Mg-based bulk metallic glasses, which can significantly improve the corrosion resistance of Mg-based alloys. This paper is a comprehensive review that compiles, analyzes and critically discusses the recent literature on the latest understanding of the processing, mechanical and biological characteristics of Mg-based bulk metallic glasses. [ABSTRACT FROM AUTHOR]

This study investigates the application of honeycomb-patterned PLA as a reinforcement in concrete structures. The research focused on identifying the optimal 3D printing layout for this reinforcement and examining how the orientation of 3D-printed PLA affects the mechanical properties of the concrete. The study compares the performance of concrete reinforced with 3D-printed PLA to both unreinforced concrete and concrete reinforced with recycled amorphous aggregate from printing waste. The results demonstrate how printing orientation influences concrete strength and the potential for using recycled PLA to enhance sustainability in construction. [ABSTRACT FROM AUTHOR]

Highlights: Pt–Ni bonded Pt single-atom (SA) catalyst, rather than classic Pt–O bonded SA catalyst, was successfully constructed. The electronic states of Pt SA catalyst were deeply regulated and negatively charged Ptδ− was realized. Pt–Ni bonded Pt SA catalyst-enhanced absorbability for activated hydrogen atoms and promoted hydrogen absorption. Single-atom (SA) catalysts with nearly 100% atom utilization have been widely employed in electrolysis for decades, due to the outperforming catalytic activity and selectivity. However, most of the reported SA catalysts are fixed through the strong bonding between the dispersed single metallic atoms with nonmetallic atoms of the substrates, which greatly limits the controllable regulation of electrocatalytic activity of SA catalysts. In this work, Pt–Ni bonded Pt SA catalyst with adjustable electronic states was successfully constructed through a controllable electrochemical reduction on the coordination unsaturated amorphous Ni(OH)2 nanosheet arrays. Based on the X-ray absorption fine structure analysis and first-principles calculations, Pt SA was bonded with Ni sites of amorphous Ni(OH)2, rather than conventional O sites, resulting in negatively charged Ptδ−. In situ Raman spectroscopy revealed that the changed configuration and electronic states greatly enhanced absorbability for activated hydrogen atoms, which were the essential intermediate for alkaline hydrogen evolution reaction. The hydrogen spillover process was revealed from amorphous Ni(OH)2 that effectively cleave the H–O–H bond of H2O and produce H atom to the Pt SA sites, leading to a low overpotential of 48 mV in alkaline electrolyte at −1000 mA cm−2 mg−1Pt, evidently better than commercial Pt/C catalysts. This work provided new strategy for the controllable modulation of the local structure of SA catalysts and the systematic regulation of the electronic states. [ABSTRACT FROM AUTHOR]

Pure silicon oxide was produced in this study utilizing a sodium silicate solution made from Kankara clay as a precursor. The Kankara clay that was obtained from Nigeria was first beneficiated to produce pure dried powder clay. After that, the dried powdered clay was treated with heat activation and acid leaching, respectively. In a 500 mL Erlenmeyer flask, appropriate amounts of each clay (raw, thermally treated clay, and leached clay) were reacted with 3M NaOH solution. The flask was heated to 200°C and stirred continuously for 3 hours on a magnetic stirring hot plate connected to a reflux condenser. The solution was filtered to yield sodium silicate solution, which was then precipitated with 3M HCl while constantly stirring to produce a gelly-like white substance. The gel was aged for 18 hours, then washed with de-ionized water several times before being dried at 80°C for 12 hours to get pure white silica particles, which were subsequently described. The XRD analysis revealed that the silicon oxide synthesized is amorphous, but the microstructure evaluation revealed particles aggregation, which is usual in sol-gel synthesized powder. [ABSTRACT FROM AUTHOR]

Polymer nanomaterials are an emanating area of research incited by the wide range of applications in solar cells, catalysis, sensors, drug delivery, electronics, bioimaging, etc., due to their outstanding mechanical, optical and electronic properties. Small dimensions in the nanometre range and a high surface-to-volume ratio of polymer nanomaterials possess distinctive features compared to bulk counterparts. In this work, doped polyvinyl alcohol (PVA) nanostructures were prepared by a one-step hydrothermal synthesis method and studied the morphological, structural and optical properties. The attained nanomaterials exhibit a spherical shape, and their average size was calculated as 3.98 nm by HR-TEM analysis. The obtained nanomaterials are dissolved in N,N-dimethyl formamide (DMF) solvent and can be employed for optoelectronic devices due to their amorphous structure and direct bandgap. Green luminescence was observed under UV light, and non-biocidal activity showed against Escherichia coli, Pseudomonas fluorescens, E. coli DH5α, Bacillus subtilis and Staphylococcus aureus. [ABSTRACT FROM AUTHOR]

Amorphous silicon carbide (a-SiC) is a wide-bandgap semiconductor with high robustness and biocompatibility, making it a promising material for applications in biomedical device passivation. a-SiC thin film deposition has been a subject of research for several decades with a variety of approaches investigated to achieve optimal properties for multiple applications, with an emphasis on properties relevant to biomedical devices in the past decade. This review summarizes the results of many optimization studies, identifying strategies that have been used to achieve desirable film properties and discussing the proposed physical interpretations. In addition, divergent results from studies are contrasted, with attempts to reconcile the results, while areas of uncertainty are highlighted. [ABSTRACT FROM AUTHOR]

The Nickel tungsten (Ni-W) alloy was electrodeposited on stainless steel (SS) substrate using potentiostatic mode at room temperature. Potentiostatic electrodeposition was carried out by varying the deposition time. The physicochemical properties of Ni-W alloys were studied using X-Ray diffraction (XRD), Electron Microscopy and micro-Raman spectroscopy. Recorded XRD spectra was compared with standard JCPDS card and the presence of Ni was confirmed, no such peaks for W were observed. Further study was extended for micro-Raman analysis. From Raman spectroscopy study the appearance of Ni-O and W6+=O bonds confirms that the Ni-W present in amorphous phase. Several cracks were observed in SEM images along with nanoparticles distributed over the electrode surface. The appearance of cracks may be correlated with the in-plane tensile stresses, lattice strains and stacking faults and maybe related to the substrate confinements. [ABSTRACT FROM AUTHOR]

In this study, the structural evolution of SiBCN ceramics during crystallization and its effects on oxidation behavior involving different atomic units or formed phases in amorphous or crystalline SiBCN ceramics were analyzed. The amorphous structure has exceptionally high oxidation activity but presents much better oxidation resistance due to its synchronous oxidation of atomic units and homogeneous composition in the generated oxide layer. However, the oxidation resistance of SiBCN ceramic will degrade during the continual crystallization process, especially for the formation of the nanocapsule-like structure, due to heterogeneous oxidation caused by the phase separation. Besides, the activation energy and rate-controlling mechanism of the atomic units and phases in SiBCN ceramics were obtained. The BNCx (Ea ​= ​145 ​kJ/mol) and SiC(2-x) (Ea ​= ​364 ​kJ/mol) atomic units in amorphous SiBCN structure can be oxidized at relatively lower temperatures with much lower activation energy than the corresponding BN(C) (Ea ​= ​209 ​kJ/mol) and SiC (Ea ​= ​533 ​kJ/mol) phases in crystalline structure, and the synchronous oxidation of the SiC(2-x) and BNCx units above 750 ​°C changes the oxidation activation energy of BNCx (Ea ​= ​332 ​kJ/mol) to that similar to SiC(2-x). The heterogeneous oxide layer formed from the nanocapsule-like structure will decrease the activation energy SiC (Ea ​= ​445 ​kJ/mol) and t-BN (Ea ​= ​198 ​kJ/mol). [ABSTRACT FROM AUTHOR]

In this study, silica (SiO2) was fabricated from a sodium silicate solution derived from an openly burned rice husk using precipitation followed by calcining at 500 oC for five hours. The calcined SiO2 was well-characterized using TGA, XRD, Raman spectroscopy, Nitrogen adsorption-desorption, FTIR, XRF, and FESEM. The results showed that the calcined SiO2 has an amorphous phase, spherical particle shape with micrometer-sized, and belongs to mesoporous material. The fabricated SiO2 was evaluated as an adsorbent for methylene blue removal from an aqueous solution using the ultrasound-assisted adsorption technique. The adsorption parameters including pH of the solution, the dosage of the adsorbent, initial concentration of dye in solution, and adsorption time were evaluated. They revealed the optimum values of 10, 2.5 g/L, 20 ppm, and 10 min, respectively. Under this optimum condition, the adsorption efficiency was found to be 98.43%. The findings implied that the fabrication of SiO2 from openly burned rice husk using a precipitation method is facile and the fabricated SiO2 could be a prospective adsorbent for removing industrial dye waste effluents. [ABSTRACT FROM AUTHOR]

In this paper, a new medium entropy alloy with nominal composition of Gd33Co33Al34 was designed and fabricated into microfibers by a melt-extraction method. The microstructure, thermophysical parameters, and magnetocaloric properties of the obtained fibers were systematically analyzed. The results showed that the as-cast fibers show an amorphous matrix with embedded in situ nano crystals. The fibers show a good magnetocaloric effect with the maximum magnetic entropy change of ~6 J/kg·K for a field change of 5 T. Notably, the fibers show excellent cooling efficiencies with an RCP and RC of ~611.72 and ~487.38 J/kg, respectively. Though the as-cast fibers possess an amorphous/nanocrystal bi-phase structure, they still exhibit a second-order transition near a Curie temperature of ~96 K. Our findings provide a promising pathway towards developing new magnetocaloric materials with good magnetocaloric performances.

Forming high‐temperature α‐Al2O3 phase under soft sparking is an intriguing phenomenon in plasma electrolytic oxidation (PEO) of Al alloys, which contradicts the low energy input of the process. In this study, α‐Al2O3 doped with black CuO is formed beneath an amorphous white outer layer on Al–Cu–Li alloy by PEO in a dilute silicate electrolyte under soft sparking. In comparison, reddish coatings with dominating γ‐Al2O3 are formed under the conventional plasma discharges, although blackish inner layer with α‐Al2O3 can also be exposed by heavily polishing the samples. In order to know the underlying mechanism, temperatures at the coating surface and the underlying substrate have been monitored by a thermocouple under the conventional and soft sparking PEO regimes, respectively. Interestingly, high temperatures are detected in the case of soft sparking rather than PEO with strong discharges. The formation of CuO, quartz, and cristobalite within the soft sparking coating also supports the existence of high temperature. Hence, the formation of α‐Al2O3 under soft sparking can be resolved to the conventional thermal activation mechanism, without the need of seeking other plausible explanations. Thermal condition evaluation for soft sparking PEO suggests that values of the effective thermal conductivity during PEO process for the outer layer and the barrier layer at the coating/substrate interface might be lower than ∼0.05 and ∼0.0017 W m−1 K−1, respectively. It is believed that the amorphous structure of the outer and barrier layers effectively blocks the heat dissipation, facilitating the formation of a highly wear‐resistant inner layer with α‐Al2O3, CuO, and the other high‐temperature species under soft sparking. [ABSTRACT FROM AUTHOR]

The need for cement as a housing construction material has continued to increase due to the growing population. This high demand increases carbon dioxide emissions. Hence, it is necessary to optimize the use of natural pozzolan material. Volcanic ash is a natural pozzolan material in North Sulawesi, but its use could be more optimal. This study aimed to determine the effect of calcination on the physical properties of volcanic ash originating from the eruption of Mount Lokon. The calcination was carried out to determine the potential of Lokon ash at different temperatures to assess the structural characteristics, mineral phases, metal oxide composition, functional group bonding, morphology, and its potential as a binder for concrete mixtures. The ash material used comes from sand taken from the Pasahapen River and filtered through a 325-mesh sieve. Lokon ash was calcined at temperatures of 800, 900, and 1000oC to determine the structural and morphological characteristics. At the same time, the effects were examined using an X-ray diffractometer (XRD), Raman spectroscopy, X-ray fluorescence (XRF), Fourier Transform InfraRed (FTIR), and Scanning Electron Microscopy (SEM). The results showed that calcination triggered the formation of hematite in the ash, which will increase its reactivity as a pozzolan material. This process causes the crystallinity of ash minerals to increase, but the ash material produced is predominantly amorphous. Hence, it has excellent potential as a binder material in concrete mixtures. [ABSTRACT FROM AUTHOR]

Using repeated bundle extrusion of a Cu/NbTi composite, we have obtained a high-strength heterophase alloy having superconducting properties. X-ray diffraction characterization has shown that the material we obtained has an unstressed, relaxed structure in the form of self-consistent, locally diffusion-alloyed atomic groups ranging widely in size, which can be divided into three groups: (1) microcrystalline long-range-ordered particles about 450 Å in size, showing up as Debye peaks with sharp tops; (2) mesoscopic clusters with a nanoscale atomic order, responsible for broad diffuse lines; and (3) small low-dimensional atomic groups with short-range order (10–50 Å), responsible for incoherent diffuse X-ray scattering (very broad diffuse halos). [ABSTRACT FROM AUTHOR]

Amorphous metal oxides (AMOs) are highly efficient oxygen evolution catalysts，which have caused a research boom in several fields in recent years owing to the unique structural advantages，easy preparation and controlled composition.In this paper，the preparation method，mechanism of oxygen evolution and distribution of amorphous structure of amorphous materials were introduced，and the research progresses of AMOs in different applications were summarized.AMOs play an important role in the hydrometallurgical electrode materials.Crystalline-amorphous (C-A) containing Fe，Ni，Co，Mo，Mn and Ti and amorphous oxides have been successfully applied in high-efficiency oxygen evolution catalyst electrodes with an oxygen evolution overpotential of 200～400 mV and a high stability and corrosion resistance.AMOs have high storage capacity and cycle life when used as energy storage materials，and act as active catalysts in new energy industries such as hydrolysis of renewable technologies and lithium batteries.Finally，the challenges and shortcomings of current AMOs applications are concluded and some research directions for improvement and deepening are putted forward for providing a reference for the preparation of new stable and environmentally friendly amorphous oxide catalytic materials.

In this work, Al2O3 nanoceramics were prepared by spark plasma sintering of amorphous powders and polycrystalline powders with similar particle sizes. Effective comparisons of sintering processes and ultimate products depending on starting powder conditions were explored. To ensure near-full density higher than 98% of the Al2O3 nanoceramics, the threshold temperature in SPS is 1450 °C for polycrystalline Al2O3 powders and 1300 °C for amorphous powders. The low SPS temperature for amorphous powders is attributed to the metastable state with high free energy of amorphous powders. The Al2O3 nanoceramics prepared by amorphous powders display a mean grain size of 170 nm, and superior mechanical properties, including high bending strength of 870 MPa, Vickers hardness of 20.5 GPa and fracture toughness of 4.3 MPa∙m1/2. Furthermore, the Al2O3 nanoceramics prepared by amorphous powders showed a larger dynamic strength and dynamic strain. The toughening mechanism with predominant transgranular fracture is explained based on the separation of quasi-boundaries. [ABSTRACT FROM AUTHOR]

We study the local structural changes along the jamming transitions in asymmetric bidisperse granular packings. The local structure of the packing is assessed by the contact orientational order, Q ~ ℓ , that quantifies the contribution of each contact configuration (Large–Large, Small–Small, Large–Small, Small–Large) in the jammed structure. The partial values of Q ~ ℓ are calculated with respect to known ordered lattices that are fixed by the size ratio, δ , of the particles. We find that the packing undergoes a structural transition at ϕ J , manifested by a sudden jump in the partial Q ~ ℓ . Each contact configuration contributes to the jammed structure in a different way, changing with δ and concentration of small particles, X S . The results show not only that the packing undergoes a structural change upon jamming, but also that bidisperse packings exhibit local HCP and FCC structures also found in monodisperse packings. This suggests that the jammed structure of bidisperse systems is inherently endowed with local structural order. These results are relevant in understanding how the arrangement of particles determines the strength of bidisperse granular packings. [ABSTRACT FROM AUTHOR]

Trimethylsilyl‐substituted polysilazanes were designed and successfully synthesized. They were used to fabricate high‐purity stoichiometric Si3N4 ceramics through pyrolysis process. Trimethylsilyl groups improved the stability of polysilazanes and easily escaped during pyrolysis, which effectively reduced oxygen and carbon content in the final polymer‐derived Si3N4. The C content of Si3N4 ceramic was below 0.06 wt%, and the O content was below 1.2 wt%. The Si3N4 ceramics remained amorphous up to 1400°C, yet they were completely transformed into α‐Si3N4 at 1500°C. Synergistic effect from low oxygen and carbon content contributed to highly stable amorphous state of Si3N4 till high temperatures. This amorphous Si3N4 ceramics could be used in cutting‐edge technology where high purity is compulsory. [ABSTRACT FROM AUTHOR]

Context: By means of ab initio molecular dynamics simulations, possible boron-rich amorphous silicon borides (BnSi1−n, 0.5 ≤ n ≤ 0.95) are generated and their microstructure, electrical properties and mechanical characters are scrutinized in details. As expected, the mean coordination number of each species increases progressively and more closed packed structures form with increasing B concentration. In all amorphous models, pentagonal pyramid-like configurations are observed and some of which lead to the development of B12 and B11Si icosahedrons. It should be noted that the B11Si icosahedron does not form in any crystalline silicon borides. Due to the affinity of B atoms to form cage-like clusters, phase separations (Si:B) are perceived in the most models. All simulated amorphous configurations are a semiconducting material on the basis of GGA+U calculations. The bulk modulus of the computer-generated amorphous compounds is in the range of 90 GPa to 182 GPa. As predictable, the Vickers hardness increases with increasing B content and reaches values of 25-33 GPa at 95% B concentration. Due to their electrical and mechanical properties, these materials might offer some practical applications in semiconductor technologies. Method: The density functional theory (DFT) based ab initio molecular dynamics (AIMD) simulations were used to generate B-rich amorphous configurations. [ABSTRACT FROM AUTHOR]

Dyes are one of the major environmental pollutants throughout the world, leading to pollution and numerous diseases. Though several techniques have been applied for the remediation of dyes, most of them are ineffective. The authors developed a halloysite clay/zinc oxide nanocomposite (HC/ZnONC) via a chemical route in the present study. The nanocomposite and its constituents, i.e., raw halloysite clay (HC) and zinc oxide nanoparticles (ZnONPs) (synthesized using the same chemical method) were analyzed for their detailed properties by sophisticated instruments. The field emission scanning electron microscope (FE-SEM) and transmission electron microscope (TEM) analysis showed spherical-shaped ZnONPs with an average size of 54.9 nm and tube-like shapes of HC with a diameter ranging from 40–200 nm and a length at the micron scale, while the nanocomposite had incorporated ZnONPs in their tube-like structures. Ultraviolet-Diffuse Reflectance Spectroscopic (UV-DRS) study revealed the photocatalytic ability of the nanocomposite with a band of 3.08 eV. A high surface area of 60.25 m2/g and the microporous and mesoporous nature of the nanocomposite were confirmed by the Brunauer–Emmet–Teller (BET) surface area analyzer. Finally, the developed nanocomposite was used for the remediation of methylene blue from the aqueous solutions, and the efficiency of removal varied from 90 to 97%. [ABSTRACT FROM AUTHOR]

Four model polymers, representing (i) amorphous homopolymers (Kollidon K30, K30), (ii) amorphous heteropolymers (Kollidon VA64, KVA), (iii) semi-crystalline homopolymers (Parteck MXP, PXP), and (iv) semi-crystalline heteropolymers (Kollicoat IR, KIR), were examined for their effectiveness in creating posaconazole-based amorphous solid dispersions (ASDs). Posaconazole (POS) is a triazole antifungal drug that has activity against Candida and Aspergillus species, belonging to class II of the biopharmaceutics classification system (BCS). This means that this active pharmaceutical ingredient (API) is characterized by solubility-limited bioavailability. Thus, one of the aims of its formulation as an ASD was to improve its aqueous solubility. Investigations were performed into how polymers affected the following characteristics: melting point depression of the API, miscibility and homogeneity with POS, improvement of the amorphous API's physical stability, melt viscosity (and associated with it, drug loading), extrudability, API content in the extrudate, long term physical stability of the amorphous POS in the binary drug–polymer system (in the form of the extrudate), solubility, and dissolution rate of hot melt extrusion (HME) systems. The obtained results led us to conclude that the physical stability of the POS-based system increases with the increasing amorphousness of the employed excipient. Copolymers, compared to homopolymers, display greater homogeneity of the investigated composition. However, the enhancement in aqueous solubility was significantly higher after utilizing the homopolymeric, compared to the copolymeric, excipients. Considering all of the investigated parameters, the most effective additive in the formation of a POS-based ASD is an amorphous homopolymer—K30. [ABSTRACT FROM AUTHOR]

The paper presents an analysis of the results of a study into diamond-like carbon films synthesized by plasma-chemical deposition from hydrocarbon sources: methane (СН4) and ethane (С2Н6). Analysis of the spectra of X-ray photoelectron spectroscopy was employed to study the effect that the synthesis conditions have on the structure and composition of amorphous carbon films.

Metallic biomaterials have been widely used in the field of medical implants for replacement purposes and/or for regeneration of tissue. Metals such as stainless steel (316 L), cobalt-chromium alloys and titanium alloys (Ti-6Al-4 V) are widely used as metallic implants today. However, they often exhibit unsatisfactory results such as stress shielding, the release of toxic ions and are often permanent and invasive – where a second surgery is required to remove the implant once the bone is fully healed. Magnesium as a biomaterial have attracted much attention recently due to its excellent biocompatibility, similar mechanical properties to bone and biodegradability. Unlike other metals and bio ceramics, the ability for magnesium alloys to undergo biodegradation eliminates the requirement for a second surgery to remove the implant. Additionally, the degradation of magnesium releases Mg2+ ions, which stimulates metabolism as they are a cofactor in numerous numbers of enzymes. Despite the advantages of magnesium alloys, the rapid degradation of magnesium proved to be challenging as the implant is unable to retain its structural integrity sufficiently enough to act as an implant. To improve the corrosion resistance of magnesium alloys, researchers have been working on the synthesis and characterization of Mg-based bulk metallic glasses, which can significantly improve the corrosion resistance of Mg-based alloys. This paper is a comprehensive review that compiles, analyzes and critically discusses the recent literature on the latest understanding of the processing, mechanical and biological characteristics of Mg-based bulk metallic glasses.

The effect produced by the application of methyl jasmonate (MeJA) in vineyards is clear, but this is a product that, despite its efficiency, is expensive, volatile and difficult to dissolve. Regarding increasing the MeJA use efficiency, new forms of application are proposed in this article, such as the use of calcium phosphate nanoparticles with two different morphologies: amorphous (ACP) and crystalline (Ap). In addition, few of the studies addressed so far have assessed MeJA's effect during the ripening period of the grapes. As a result of this, in this article, we evaluated/studied for first time the effect of the different MeJA formats on the phenolic composition of the grape during the ripening period. The results showed small differences between the two morphologies of the nanoparticles, which promoted a significant a delay in the sugar accumulation and an increase in the different phenolic compounds compared to the control. Such improvements were not as significant as those induced by the conventional MeJA treatment. However, it is remarkable that when the nanoparticles were applied, we used a concentration 10 times lower than when it is used conventionally. Therefore, these findings revealed that both types of calcium phosphate nanoparticles are potential MeJA nanocarriers allowing for the increase in the quality of the grapes at the time of harvest in a more sustainable way, although future studies must be carried out in order to optimise the concentration with which these nanoparticles are doped. [ABSTRACT FROM AUTHOR]

Every year a large amount of coal fly ash (CFA) is generated and dumped in fly ash ponds. Fly ash has numerous toxic heavy metals, which leads to water pollution due to the percolation of these heavy metals. Heavy metal toxicity has become a major issue for the whole globe. Moreover, CFA has several value-added minerals, such as silica, alumina, and ferrous in large amounts. Therefore, the synthesis of silica nanoparticles from CFA and their application for the removal of toxic heavy metals from fly ash aqueous solution will prove to be an economical and efficient approach. Here, in the present research work, investigators synthesized nanosilica from CFA by alkali dissolution and sol-gel methods and applied them for heavy metal removal. Firstly, CFA was treated with high molar NaOH, along with stirring and heating. Further, the sodium silicate leachate from CFA was treated with dilute HCl till the formation of a white gel at neutral pH. Purification of the nanosilica was achieved by treating with 1M HCl along with stirring followed by calcination at 400 °C for 4 h. The synthesized nanosilica was characterized by UV-Vis, Fourier transform infrared (FTIR), particle size analyzer (PSA), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), electron diffraction spectroscopy (EDS), and high-resolution transmission electron microscope (HR-TEM). The sizes of the floral-shaped nanosilica particles were 20–70 nm, and the purity was 90–95%, as confirmed by microscopy and EDS, respectively. The XRD and FTIR revealed the amorphous nature of nanosilica. Finally, the potential of the nanosilica was assessed for the removal of heavy metals from 20% CFA aqueous solutions in batch experiments. The nanosilica showed about 40–90% removal of heavy metals (Al, Pb, Cd, Cu, Cr, Ni, Co, Zn, Mn) from the fly ash aqueous solution. [ABSTRACT FROM AUTHOR]

Amorphous silicon oxycarbides are known to be an effective anode material for lithium‐ion batteries. Despite their exceptional properties and high charge capacities, however, their practical uses are limited by their significant first‐cycle loss, considerable hysteresis, and low cyclic ability. Comparatively, SiOC/metal oxide materials have demonstrated increased rate capability and cyclic stability. This study utilized a liquid precursor‐derived ceramic method to modify SiOC with titanium (IV) butoxide precursor to synthesize SiOC/TiOxCy. X‐ray diffractograms confirmed the amorphous nature of SiOC/TiOxCy. The elemental composition and bonding properties were investigated using X‐ray photoelectron spectroscopy, and electron microscopy was used to explore morphological features. In the first cycle, the reversible capacity of pyrolyzed SiOC/TiOxCy was 520 mAh g−1, which then increased to 736 mAh g−1 for the 1200°C annealed SiOC/TiOxCy due to the increased free carbon network and TiC conductive phases. The irreversible capacity of the first cycle was 568 mAh g−1, which was lower than the annealed SiOC irreversible capacity of 695 mAh g−1. Interestingly, the rate stability of the pyrolyzed SiOC/TiOxCy performed more stability than the annealed sample. Localized carbothermal reactions between amorphous SiOC/TiOxCy and free carbon at annealing temperatures resulted in loss of structure stability. [ABSTRACT FROM AUTHOR]

Hard chromium coatings have demonstrated their performance for several decades, particularly for their wear and corrosion resistance properties. However, the traditional process using chromium trioxide (CrO3) is very toxic and is intended to disappear in the European Union by 2024, thanks to the REACH regulation. This study aimed to determine the residual stress of amorphous chromium deposits elaborated from baths containing trivalent chromium ions. However, the amorphous structure of these deposits does not allow the determination of residual stresses by conventional means. In this study, we propose adapting a recent method called "FIB-DIC", which is not limited by the material's crystalline structure compared to the classical X-ray diffraction (XRD) analysis. The method is based on the measurement of relaxation-induced displacement fields following the ablation of material on a very local scale. The results obtained by the classical (XRD) and the FIB-DIC method on crystallized heat-treated Cr(III) deposits are 296 ± 45 and 377 ± 275 MPa. Then, the FIB-DIC technique allowed us to evaluate a residual stress level of 479 ± 359 MPa for amorphous trivalent chromium coating, which has never been performed before. [ABSTRACT FROM AUTHOR]

Magnesium-zinc-calcium (Mg-Zn-Ca) alloys as a biomaterial have attracted much attention recently, owing to their excellent biocompatibility, similar mechanical properties to natural bone, and biodegradable properties. Despite the numerous advantages of MgZnCa alloys, the rapid degradation of magnesium proved challenging as the implant in unable to retain its structural integrity for a sufficient duration of time. For metallic glasses, the capability to produce a bulk sample that is sufficiently large for useful applications have been far less successful owing to challenging processing parameters that are required for rapid cooling. In this study, Mg65Zn30Ca5 melt-spun ribbons were produced using melt-spinning followed by spark plasma sintering under high pressure (60 MPa) at different temperatures (130–170 °C) to provide an insight into the consolidation, mechanical, and corrosion behavior. Microstructural interfaces were characterized using scanning electron microscopy while the thermal stability of the amorphous phase was characterized using differential scanning calorimetry and X-ray diffraction. Here, pellets with 10 mm diameter and 10 mm height with a complete amorphous structure were achieved at a sintering temperature of 150 °C with densification as high at ~98%. Sintering at higher temperatures, while achieving higher densification, resulted in the presence of nano-crystallites. The mechanical properties were characterized using microhardness and compression tests. The hardness values of the sintered products were relatively higher to those containing crystallite phases while the ultimate compressive strength increased with increasing sintering temperature. Bio-corrosion properties were characterized via electrochemical testing with PBS as the electrolyte at 37 °C. The corrosion results suggest that the sintered samples have a significantly improved corrosion resistance as compared to as-cast samples. More notably, SPS150 (samples sintered at 150 °C) exhibited the best corrosion resistance (35× compared to as-cast in the context of corrosion current density), owing to its single-phase amorphous nature. This study clearly shows the potential of spark plasma sintering in consolidating amorphous ribbons to near-full density bulk pellets with high corrosion resistance for bio-applications. [ABSTRACT FROM AUTHOR]