Multifunctional antifogging (AF) coatings consisting of alternating layers of positively charged ZrO2 nanoparticles (NPs) and negatively charged SiO2 NPs were rapidly fabricated via spray-spin-blow layer-by-layer electrostatic assembly followed by calcination. The resultant coatings of only three bilayers exhibited excellent AF, superhydrophilic, antireflective (AR), and self-cleaning (SC) properties, as well as high mechanical stability. These were demonstrated by various methods, e.g., transmission and scanning electron microscopy, X-ray diffraction, UV-Vis spectrometry, a contact angle test, a boiling test (constant 100 °C), a low-temperature test, and mechanical stability tests. ZrO2 and SiO2 NPs were synthesized and utilized as building blocks for fabricating the coatings. The resultant coatings exhibited excellent AF and SC properties due to the superhydrophilicity of the coating, showed excellent AR properties due to the quarter-wave coating with a low refractive index, and exhibited excellent superhydrophilic properties due to a rough microtextured surface. The simplicity of the fabrication process, easy availability of the nanomaterials, and excellent adhesion to substrates for the coating preparation might make the low-cost, nontoxic, and eco-friendly multifunctional coatings potentially useful in optical and display devices.

Deformation twins have a major role in the microstructure evolution of hexagonal close packed (HCP) metals. Voids are common defects in metals and have a significant impact on their properties. In this work, using molecular dynamics, a tension simulation of single-crystal titanium (Ti) with different void sizes under uniaxial stress conditions was performed. The results showed that the evolution and dominance of the $\left\{ {10\bar{1}2} \right\}$ twin system using the Henning potential was not consistent with the Schmid criterion when the single-crystal Ti contained void defects. From a microscopic perspective, the authors analyzed the relationship between the nucleation and growth of twins and the emission of dislocation loops. The authors found that the existence of voids not only contributes to the emission of dislocation loops but also hinders the movement of these loops. With the increase in void size, the peak dislocation density of ${1 \over 3}\left\langle {\bar{1}100} \right\rangle$ partial dislocation loops decreased. This work is helpful to further investigate the nucleation and evolution of tension twins and to form an effective growth criterion for twins to study the twinning process of HCP metals during plastic deformation.

The basis of the virtual machine concept, which is commonly used in coordinate measuring machines, was implemented to determine more realistic uncertainties on the estimation of the elastic modulus obtained from nanoindentation tests. The methodology is based on a mathematical model applied to simulate the testing process and to evaluate the uncertainties through Monte Carlo simulations whose application depends on the studied system (instrument, material, scale, etc.). The methodology was applied to the study of fused silica (FQ) and steel samples tested in a nanoindentation system. The results revealed that the most relevant sources of uncertainty are related to the calibration procedure, particularly to the elastic modulus of the calibration material, and to the contact depth estimation; however, the relevance of the uncertainties is system dependent. This work represents a first insight for a deeper consideration of the uncertainties in instrumented indentation testing.

Uniform distribution of diamond grains is difficult to achieve using traditional fabrication of the micro grinding wheel. The design and performance of novel resinous diamond composites (RDCs) fabricated by hot pressing molding were studied to fabricate micro resinous diamond grinding wheels. The physical and mechanical properties of RDCs were analyzed by constructing and simulating five kinds of RDCs, including acrylonitrile butadiene styrene (ABS)/polyvinyl chloride (PVC)/dioctyl phthalate (DOP)/diamond materials with different mass ratios. Diamond grains presented good compatibility with the ABS–PVC–DOP copolymer, which resulted in improved mechanical properties of RDCs. RDC1–RDC5 samples were fabricated, and their hardness, surface roughness, and infrared spectra were analyzed. The optimal mass ratio of ABS/PVC/diamond/DOP for fabricating RDCs was 62.5/18.6/10.6/8.3. The results provide guidance in fabricating novel materials for resinous diamond grinding wheels with desirable performances for precision and ultraprecision machining.

Enthalpies of water adsorption on amorphous and crystalline oxides and peroxides of uranium are reported. Despite substantial structural and computational research on reactions between actinides and water, understanding their surface interactions from the energetic perspective remains incomplete. Direct calorimetric measurements of hydration energetics of nano-sized, bulk-sized UO2, U3O8, anhydrous γ-UO3, amorphous UO3, and U2O7 were carried out, and their integral adsorption enthalpies were determined to be −67.0, −70.2, −73.0, −84.1, −61.6, and −83.6 kJ/mol water, with corresponding water coverages of 4.6, 4.5, 4.1, 5.2, 4.4, and 4.1 H2O per nm2, respectively. These energetic constraints are important for understanding the interfacial phenomena between water and U-containing phases. Additionally, this set of data also helps predict the absorption and desorption behavior of water from nuclear waste forms or used nuclear fuels under repository conditions. There are also underlying relations for water coverage among different U compounds. These experimentally determined data can be used as benchmark values for future computational investigations.

The microstructure evolution of a typical nickel-based superalloy was studied in the strain range of 0.1–0.9 at 1110 °C/0.01 s−1 by using the electron backscattered diffraction technique. It was found that the evolution of recrystallized microstructures, grain boundary characteristics, and textures was closely related to strain level. With the increasing strain level, the fraction of equiaxed dynamic recrystallization (DRX) grains increased significantly at the expense of the large non-recrystallized grains, and there was a decrease in total low angle grain boundaries fraction and a simultaneous increase in the fraction of high angle grain boundaries. In addition, the occurrence of DRX promoted the formation of Σ3 boundaries, and the coherent Σ3 boundaries were much easier to form at the strain above 0.5. On the other hand, 〈100〉 component of the textures became stronger with the increasing strains, and the lack of 〈111〉 orientations can also be observed in the textures at high strains above 0.7.

The realization of an electrically driven organic solid-state laser is an ambitious but highly desirable goal. Many obstacles need to be solved before a working device can be realized. One of the most challenging tasks is an incorporation of intracavity metal contacts, which, on the one hand, would not substantially degrade optical properties of the whole device and, on the other hand, would ensure sufficient current density to reach lasing. In this paper, we present different contact compositions aiming to realize high-quality intracavity metal contacts. We build a top contact consisting of 0.5 nm of aluminum and 4 nm of silver which has a conductivity of 1.9 × 107 (Ω/m) and is not increasing the optical lasing threshold of an organic microcavity. To get a better understanding of charge carriers influencing the device performance, we have performed a set of measurements, where a hybrid OLED–MC device was excited both optically and electrically at the same time. These experiments suggest that the charge carriers do not degrade electrical performance, at least for current densities in the range of A/cm2. Moreover, our observations suggest that, in some cases, simultaneous optical excitation can contribute to more efficient electrical pumping of the OLED-MC device.

In this work, a multifunctional system was developed in which antibacterial and luminescent properties were inserted into the matrix of hydroxyapatite (HAp) and its efficiency as a support for an antineoplastic drug was evaluated, aiming its application in the treatment of osseous diseases. The precipitation method was used for the synthesis of HAp, EuCl3 was used for the incorporation of Eu3+ as imaging agents, silver nanoparticles (AgNPs) with antimicrobial function were used, and a model of drug, 5-fluorouracil (5FU) was used. The developed material is characterized by several techniques, where crystalline peaks attributed to HAp were identified in the X-ray diffractogram, whereas the luminescence spectrum of the material presented emissions attributed to the Eu3+ ion. The identification and the uniform distribution of AgNPs, 5FU, and Eu3+ were confirmed by mapping the sample using energy-dispersive spectroscopy. The measurements indicated that 82% (±2.8) of 5FU was incorporated into the HAp matrix, and a gradual and increasing release of it as a function of time was observed. Assays carried out for different bacteria confirmed the antimicrobial action of the samples and the efficiency of the drug inserted into the matrix. An in vitro assay showed the bioactivity of the material and its potential to bind to living osseous tissue.

The improvement of hydrogen embrittlement (HE) is a key problem for transition-metal silicides. Although C40 TMSi2 disilicides are attracted candidates for ultrahigh-temperature applications, the HE mechanism of TMSi2 is unclear. Importantly, the role of hydrogen on the structural configuration, elastic modulus, and hardness of TMSi2 is entirely unknown. To reveal the HE, we study the role of hydrogen in TMSi2 (TM = Nb, Mo, and W) based on the first-principles calculations. Four H-doped sites are considered in detail. The calculated results show that hydrogen is favorable to occupy the octahedral interstitial site because the C40 TMSi2 layered structure is favorable to absorb hydrogen. H-doping results in lattice expansion of c-axis compared with the a-axis and b-axis. H-doping obviously reduces the elastic modulus and hardness of TMSi2 due to the interaction between hydrogen and TMSi2. In addition, H-doping changes the electronic properties of MoSi2 and WSi2.

La3+-doped BaSnO3 microtubes (La3+–BaSnO3) have been synthesized by electrospinning method, and the influence of La3+ content on the sensing properties of BaSnO3 for detection of formaldehyde vapor has been investigated. The as-prepared materials have been characterized using XRD, SEM, DSC, XPS, and UV-Vis. The La3+–BaSnO3 sample doped with 4 wt% La exhibited a response as high as 220 to formaldehyde vapor (1000 ppm concentration) along with a very low detection limit of 0.1 ppm at 270 °C, whereas at 140 °C, it exhibited a response of 80 and detection limit of 1 ppm. In addition, the sensor showed excellent selectivity of 57 to formaldehyde at 140 °C when compared with other vapors. Further, the sensor also showed good repeatability and stability over a long period of time suggesting its strong potential as a commercial formaldehyde sensor.

Nanodomained heterogenous structures characterized by randomly dispersed nanograins (NGs) embedded in the coarser grains (CGs) have demonstrated an exciting potential to break the strength–ductility trade-off, providing high strength without the loss of ductility. Here, using a combination of discrete crystal plasticity finite element (discrete-CPFE) model and dislocation density-based CPFE model, we study the effects of grain size, volume fraction of nanograins on the strength and deformation in nanodomained materials. Our analysis shows that the overall flow stresses of nanodomained samples are equal or higher than the strengths predicted by rule of mixtures. Smaller NGs or higher volume fraction of NGs can make the nanodomained samples stronger, as they can be more effective to promote the dislocation accumulations inside the CGs and eventually raise the critical resolved shear stress for each slip system during the plastic flow. Areas surrounding NGs stored higher dislocation densities and less plastic strain, due to the restricted dislocation motion. Furthermore, NGs grain embedded in the CGs can effectively reduce the anisotropy of strength in the nanodomained samples.

The influence of repeated thermal cycling on mechanical properties, structural relaxation, and evolution of the potential energy in binary glasses is investigated using molecular dynamics simulations. The authors consider a binary mixture annealed with different cooling rates and then exposed to one thousand thermal cycles at constant pressure. It is found that during the first few hundred transient cycles, the potential energy minima after each cycle gradually decrease and the structural relaxation proceeds through collective, irreversible displacements of atoms. With increasing cycle number, the amplitudes of the volume and potential energy oscillations are significantly reduced, and the potential energy minima saturate to a constant value that depends on the thermal cycling amplitude and the initial cooling rate. In the steady state, the glasses thermally expand and contract but most of the atoms return to their cages after each cycle, similar to limit cycles found in periodically driven amorphous materials. The results of tensile tests demonstrate that the elastic modulus and the yielding peak, evaluated after the thermal treatment, acquire maximum values at a particular thermal cycling amplitude, which coincides with the minimum of the potential energy.

Irradiation resistance of metallic nanostructured multilayers is determined by the interactions between defects and phase boundaries. However, the dose-dependent interfacial morphology evolution can greatly change the nature of the defect–boundary interaction mechanisms over time. In the present study, we used atomistic models combined with a novel technique based on the accumulation of Frenkel pairs to simulate irradiation processes. We examined dose effects on defect evolutions near zirconium–niobium multilayer phase boundaries. Our simulations enabled us to categorize defect evolution mechanisms in bulk phases into progressing stages of dislocation accumulation, saturation, and coalescence. In the metallic multilayers, we observed a phase boundary absorption mechanism early on during irradiation, while at higher damage levels, the increased irradiation intermixing triggered a phase transformation in the Zr–Nb mixture. This physical phenomenon resulted in the emission of a large quantity of small immobile dislocation loops from the phase boundaries.

The microstructure contribution to the very low fracture toughness of freestanding metallic thin films was investigated by bulge fracture tests on 200-nm-thick {100} single-crystalline and polycrystalline silver films. The single-crystalline films exhibited a significantly lower fracture toughness value (KIC= 0.88 MPa m1/2) than their polycrystalline counterparts (KIC= 1.45 MPa m1/2), which was rationalized by the observation of an unusual crack initiation behavior—characterized by twinning in front of the notch tip—during in situ testing in the atomic force microscope. Twinning was also observed as a dominant deformation mechanism in atomistic simulations. This twinning tendency is explained by comparing the resolved shear stresses acting on the leading partial dislocation and the full dislocation, which allows to develop a size- and orientation-dependent twinning criterion. The fracture toughness of polycrystalline samples was found to be higher because of the energy dissipation associated with full dislocation plasticity and because of crack meandering along grain boundaries.

Ternary Al–15 wt% Cu–7 wt% Si and Al–22 wt% Cu–7 wt% Si alloy specimens were generated by transient directional solidification (DS) and rapid solidification (RS) techniques. The microstructures are constituted by an α-Al dendritic matrix surrounded by two eutectic, that is, a binary eutectic (Si + α-Al) and a bimodal eutectic, consisting of cellular-type binary eutectic colonies (α-Al + Al2Cu) in a ternary eutectic matrix consisting of α-Al + Al2Cu + Si. The bimodal eutectic exists at cooling rates from 0.5 to 250 K/s. The secondary dendritic spacing, λ2, of the DS samples varied from 5 to 20 μm and from 10 to 18 μm for both examined alloys. The λ2 from 2.7 to 4.0 μm characterized the RS samples. Mechanical properties have been determined for various samples related to different dendritic spacing values. Based on the evaluation of the rapidly solidified microstructures, it was possible to assess the cooling rates.

Hierarchically porous poly(L-lactic acid) (PLLA)/poly(ε-caprolactone) (PCL) monolithic composites were fabricated by nonsolvent-induced phase separation (NIPS) method without any template for the first time. A homogeneous hierarchical porous structure with relatively large specific surface area containing both mesopores and macropores was confirmed by pore size distribution plots and scanning electron microscopy images, respectively. Fourier transform infrared analysis (FTIR) revealed that PLLA and PCL were physically blended. Differential scanning calorimeter (DSC) analysis further showed that the two components were physically blended but had a slight thermal compatibility. Meanwhile, X-ray diffraction (XRD) tests indicated that the addition of PCL hindered the crystallization of PLLA. Herein, the formation of the mesopores and macropores during the phase separation process was explained from the microscopic point of view according to the results of XRD and DSC. The present monolithic composites with hierarchically porous structures had promising prospect for applications of tissue engineering.

Fe–6.5 Si–0.05 B alloy was used in the study to investigate the texture evolution and magnetic property of the ferromagnetic crystal under an axial high magnetic field during bulk solidification. Optical microscopy (OM) and X-ray diffraction (XRD) were applied to analyze the microstructures and texture evolution of the alloy solidified under different magnetic field intensities. The result shows that with an increase in the magnetic field intensity from 0 to 2 T, the texture gradually changes from random orientation to {100} 〈120〉, eventually becoming a mixture of cube and Goss texture. The alloys treated at 1 and 2 T showed magnetic anisotropic behavior, while the alloy treated at 0 T showed magnetic isotropic behavior. The change in magnetic property comes from the evolution of α-Fe crystal orientation. Furthermore, a method for controlling the crystallization process and crystallographic orientation by adjusting the magnetic field intensity was proposed.

The global market requirement of ultra-fine iron powder (UFIP), with a range size of 0.1–1 μm, is more than 20,000 tons per annum. However, no low-cost nontoxic synthesis route of UFIP is known. In this study, we used the low-cost, rapid, and scalable flame aerosol synthesis (FAS) method to synthesize iron oxide nanoparticles with different size and morphology. Combining with a postreduction heat treatment process, a feasible synthesis route of UFIP which meets the commercial production criteria has been developed. By optimizing the precursor concentration and postreduction heat treatment parameters, the final particle size of UFIP can be controlled. The evolution of the microstructure, phase formation, and magnetic properties during the postreduction heat treatment are systematically investigated, and a feasible reaction model has been established. This work provides an important starting point for the facile commercial synthesis of UFIP and can be readily expanded to other pure metals.

In the current research, the application and capability of electric discharge treatment (EDT) for enhancing the cytocompatibility and tribological properties of medical-grade Co–Cr alloy were investigated. The Co–Cr specimens were treated by copper tungsten (Cu–W) electrode in a deionized water tank (dielectric medium) at different spark energy levels. To examine the cytocompatibility of substrates, the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay was performed to evaluate the substrate cell viability. Furthermore, the wear rate and coefficient of friction of the substrates were examined on a pin-on-disc tribometer. In vitro cytocompatibility results revealed that the % viability of the MG-63 cells on EDT sample was approximately two times improved compared with that on the untreated surface. The tribological results showed that the treated samples have better friction reducing properties and four times higher wear resistance compared with unmachined Co–Cr samples. The surface modification at 10 A current and 60 µs pulse on-time and 150 µs off-time were found as significant parameters in both assessments.

Recently, double perovskite-based oxide materials have been proposed for thermoelectric (TE) applications due to their environment-friendly nature, high-temperature stability, better oxidation resistance, and lower processing cost compared to conventional chalcogenides and intermetallics. In this review article, we have comprehensively summarized our recent research studies on Sr2B′B″O6-based double perovskites for high-temperature TE power generation. We have shown that decoupling of phonon-glass and electron-crystal behavior is possible in oxides by reducing thermal conductivity due to induced dipolar glassy state as a result of relaxor ferroelectricity. We have also introduced metal-like electrical conductivity (∼105 S/m) in these ceramics that are inherently insulator in nature. Moreover, we have observed interesting behavior of temperature-driven p–n type conduction switching assisted colossal change in thermopower in some of these oxides, hitherto, obtained only in chalcogenides. The charge transport mechanism in these complex oxides has been analyzed by small polaron hopping conduction model in conjugation with defect chemistry.